sirolimus and Neoplasms

Cancer is the most serious problem for public health. Traditional treatments often come with unavoidable side effects. Therefore, the therapeutic effects of natural products with wide sources and low toxicity are attracting more and more attention. Polysaccharides have been shown to have cancer-fighting potential, but the molecular mechanisms remain unclear. The mammalian target of rapamycin (mTOR) pathway has become an attractive target of antitumor therapy research in recent years. The regulation of mTOR pathway not only affects cell proliferation and growth but also has an important effect in tumor metabolism. Recent studies indicate that dietary polysaccharides play a vital role in cancer prevention and treatment by regulating mTOR pathway. Here, the progress in targeting mTOR signaling by dietary polysaccharides in cancer prevention and their molecular mechanisms are systemically summarized. It will promote the understanding of the anticancer effects of polysaccharides and provide reference to investigators of this cutting edge field.

Topics: Humans; Neoplasms; Polysaccharides; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The signalling system known as mammalian target of rapamycin (mTOR) is believed to be required for several biological activities involving cell proliferation. The serine-threonine kinase identified as mTOR recognises PI3K-AKT stress signals. It is well established in the scientific literature that the deregulation of the mTOR pathway plays a crucial role in cancer growth and advancement. This review focuses on the normal functions of mTOR as well as its abnormal roles in cancer development.

Topics: Carcinogenesis; Cell Proliferation; Cell Transformation, Neoplastic; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Sirolimus; TOR Serine-Threonine Kinases

The phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway regulates proliferation, survival and metabolism, and its dysregulation is one of the most frequent oncogenic events across human malignancies. Over the last two decades, there has been significant focus on the clinical development of PI3K pathway inhibitors. More than 40 different inhibitors of this axis have reached various stages of clinical trials, but only a few of them have been approved by the Food and Drug Administration (FDA) for cancer treatment. These clinical results, however, could be improved given the importance of PI3K signaling in cancer and its role in linking cancer growth with metabolism. In this systematic review, after a glance at PI3K/AKT/mTOR pathway and its different inhibitors, we retrieved registered clinical trials evaluating the efficacy and safety of PI3K/AKT/mTOR inhibitors on Clinicaltrials.gov. Following the extraction of the data, finally we analyzed 2250 included studies in multiple steps, beginning with an overview and moving on to the details about type of malignancies, inhibitors, and treatment strategies. We also took a closer look at more than 100 phase III-IV clinical trials to pinpoint promising therapies, hoping that presenting a comprehensive picture of current clinical trials casts a flash of light on what remains to be done in future clinical trials of PI3K/AKT/mTOR inhibitors in human malignancies.

Topics: Humans; MTOR Inhibitors; Neoplasms; Phosphatidylinositol 3-Kinase; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is a protein kinase that controls cellular metabolism, catabolism, immune responses, autophagy, survival, proliferation, and migration, to maintain cellular homeostasis. The mTOR signaling cascade consists of two distinct multi-subunit complexes named mTOR complex 1/2 (mTORC1/2). mTOR catalyzes the phosphorylation of several critical proteins like AKT, protein kinase C, insulin growth factor receptor (IGF-1R), 4E binding protein 1 (4E-BP1), ribosomal protein S6 kinase (S6K), transcription factor EB (TFEB), sterol-responsive element-binding proteins (SREBPs), Lipin-1, and Unc-51-like autophagy-activating kinases. mTOR signaling plays a central role in regulating translation, lipid synthesis, nucleotide synthesis, biogenesis of lysosomes, nutrient sensing, and growth factor signaling. The emerging pieces of evidence have revealed that the constitutive activation of the mTOR pathway due to mutations/amplification/deletion in either mTOR and its complexes (mTORC1 and mTORC2) or upstream targets is responsible for aging, neurological diseases, and human malignancies. Here, we provide the detailed structure of mTOR, its complexes, and the comprehensive role of upstream regulators, as well as downstream effectors of mTOR signaling cascades in the metabolism, biogenesis of biomolecules, immune responses, and autophagy. Additionally, we summarize the potential of long noncoding RNAs (lncRNAs) as an important modulator of mTOR signaling. Importantly, we have highlighted the potential of mTOR signaling in aging, neurological disorders, human cancers, cancer stem cells, and drug resistance. Here, we discuss the developments for the therapeutic targeting of mTOR signaling with improved anticancer efficacy for the benefit of cancer patients in clinics.

Topics: Humans; Mechanistic Target of Rapamycin Complex 1; Neoplasms; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mechanistic/mammalian target of rapamycin (mTOR) is the crucial hub of signalling pathways that regulate essential steps in the cell life cycle. Once incorporated in the mTORC1 complex, mTOR phosphorylates the eukaryotic initiation factor 4E (eIF4E)- binding protein 1 (4E-BP1), which then releases eIF4E. When not bound to 4EBPs, eIF4E recognizes the mRNA 5'-cap structure and, together with eIF4A and eIF4G, it forms the eIF4F complex that recruits the ribosome on the mRNA. Under normal conditions, the cellular concentration of eIF4E is very low, making eIF4E the limiting factor in the initiation of protein synthesis. The vast majority of cancer types are characterized by the simultaneous deregulation of the mTOR/4E-BP1 signalling pathway and upregulation of eIF4E, which lead to an increased expression of cancer-promoting genes and deregulated cellular growth. Over the last decades, a growing number of selective inhibitors of the mTOR/4E-BP1/eIF4E pathway have been discovered or designed. Several inhibitors with encouraging preclinical results have been tested in clinical trials. This review summarizes the most recent research on drug development against mTOR, 4E-BP1, and eIF4E, describing the design rationale and the available structural and functional data on the most promising compounds.

Topics: Antineoplastic Agents; Cell Cycle Proteins; Eukaryotic Initiation Factor-4E; Humans; Neoplasms; Phosphoproteins; Phosphorylation; RNA, Messenger; Sirolimus; TOR Serine-Threonine Kinases

Rapamycin inhibits the mechanistic (formally mammalian) target of rapamycin (mTOR), an evolutionarily conserved intracellular kinase that influences activation of growth signaling pathways and immune responses to malignancy. Rapamycin has been found to have both immunosuppressant and immunostimulatory effects throughout the innate and adaptive responses based on the inhibition of mTOR signaling. While the immunosuppressant properties of rapamycin and mTOR inhibition explain rapamycin's success in the prevention of transplant rejection, the immunostimulatory characteristics are likely partially responsible for rapamycin's anti-neoplastic effects. The immunologic response to rapamycin is at least partially dependent on the dose and administration schedule, with lower doses inducing immunostimulation and intermittent dosing promoting immune function while limiting metabolic and immunosuppressant toxicities. In addition to its FDA-approved application in advanced malignancies, rapamycin may be effective as a chemopreventive agent, suspending progression of low-grade cancers, preventing invasive conversion of in situ malignancy, or delaying malignant transformation of established pre-malignant conditions.

Topics: Chemoprevention; Humans; Immunosuppressive Agents; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

The serine/threonine kinase Akt is a major player in the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway, and its modulation impacts multiple cellular processes such as growth, proliferation, and survival. Several abnormalities in this pathway have been documented over the years, and these alterations were shown to have great implications in tumorigenesis and resistance to chemotherapy. Thus, multiple Akt inhibitors have been developed and tested in adult tumors, and some of them are currently undergoing phase I, II, and III clinical trials for distinct cancers that arise during adulthood. Despite that, the impact of these inhibitors is still not fully understood in pediatric tumors, and Akt-specific targeting seems to be a promising approach to treat children affected by cancers. This review summarizes recent available evidence of Akt inhibitors in pediatric cancers, from both preclinical and clinical studies. In short, we demonstrate the impact that Akt inhibition provides in tumorigenesis, and we suggest targeting the PI3K/Akt/mTOR signaling pathway, alone or in combination with other inhibitors, is a feasible tool to achieve better outcomes in pediatric tumors.

Topics: Adult; Carcinogenesis; Child; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Sirolimus; TOR Serine-Threonine Kinases

The drug rapamycin is a potent inhibitor of the mTOR complex, acting directly in the signaling cascade of this protein complex; interrupting cell proliferation, in addition to being an extremely efficient immunosuppressant. Currently this drug is being used in several types of cancer. Rapamycin has been a target of great interest within nanomedicine involving nanostructured systems for drug delivery aiming to increase the bioactivity and bioavailability of this drug. In addition, there is a constant search for analytical methods to identify and quantify this drug. Numerous high-performance liquid chromatography analytical techniques, mass spectrometry and immunoassay techniques have been employed efficiently in an attempt to develop increasingly sensitive analytical methods. Thus, this review sought to bring together current and relevant scientific works involving rapamycin and; besides analytical methods more used for quantification of this molecule.

Topics: Humans; Mass Spectrometry; Neoplasms; Pharmaceutical Preparations; Signal Transduction; Sirolimus

Phosphoinositide-3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway inhibitors are a novel class of antineoplastic agent available for the treatment of various cancers. With improved cancer outcomes and survival, individuals are exposed to these antineoplastic therapies for longer periods of time and therefore, the consideration of adverse effects is of increasing importance. The PI3K/Akt/mTOR signaling pathway plays a critical role in regulating cellular processes such as growth and proliferation, but also regulates the metabolic effects of insulin such as glucose uptake and glycogen synthesis. Therefore, hyperglycemia and insulin resistance are frequently reported adverse effects. There are no recent consensus guidelines on the management of hyperglycemia secondary to PI3K/Akt/mTOR inhibitors, with the latest guidelines produced in 2012 - when many of these agents were still undergoing development. As we now have a greater understanding of the underlying mechanisms and patterns in which hyperglycemia is induced and access to an increasing array of glucose-lowering agents, an update of the previous guidelines accommodating these understandings and developments is timely. This review will provide a comprehensive summary of the current literature with regards to the incidence of hyperglycemia associated with each agent, as well as the different pathways and mechanisms in which hyperglycemia is induced. Our proposed up-to-date strategy for the specific management of PI3K/Akt/mTOR inhibitor-induced hyperglycemia will also aim to facilitate management of this complex oncological population.

Topics: Antineoplastic Agents; Humans; Hyperglycemia; Neoplasms; Phosphatidylinositol 3-Kinase; Phosphatidylinositol 3-Kinases; Phosphatidylinositols; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Sirolimus; TOR Serine-Threonine Kinases

Overexpression of HECT-type E3 ubiquitin ligase SMURF1 is correlated with poor prognosis in patients with various cancers, such as glioblastoma, colon cancer, and clear cell renal cell carcinoma. SMURF1 acts as a tumor promoter by ubiquitination modification and/or degradation of tumor-suppressing proteins. Combined treatment of Smurf1 knockdown with rapamycin showed collaborative antitumor effects in mice. This review described the role of HECT, WW, and C2 domains in regulating SMURF1 substrate selection. We summarized up to date SMURF1 substrates regulating different type cell signaling, thus, accelerating tumor progression, invasion, and metastasis. Furthermore, the downregulation of SMURF1 expression, inhibition of its E3 activity and regulation of its specificity to substrates prevent tumor progression. The potential application of SMURF1 regulators, specifically, wisely choose certain drugs by blocking SMURF1 selectivity in tumor suppressors, to develop novel anticancer treatments.

Topics: Animals; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Humans; Mice; Neoplasms; Promoter Regions, Genetic; Sirolimus; Ubiquitin-Protein Ligases; Ubiquitination

Plant-based diets are becoming more popular for many reasons, and epidemiological as well as clinical data also suggest that a well-balanced vegan diet can be adopted for the prevention, and in some cases, in the treatment of many diseases. In this narrative review, we provide an overview of the relationships between these diets and various conditions and their potential biochemical background. As whole plant foods are very rich in food-derived antioxidants and other phytochemicals, they have many positive physiological effects on different aspects of health. In the background of the beneficial health effects, several biochemical processes could stand, including the reduced formation of trimethylamine oxide (TMAO) or decreased serum insulin-like growth factor 1 (IGF-1) levels and altered signaling pathways such as mechanistic target of rapamycin (mTOR). In addition, the composition of plant-based diets may play a role in preventing lipotoxicity, avoiding N-glycolylneuraminic acid (Neu5Gc), and reducing foodborne endotoxin intake. In this article, we attempt to draw attention to the growing knowledge about these diets and provide starting points for further research.

Topics: Animals; Antioxidants; Biochemical Phenomena; Diet; Diet, Vegan; Endotoxemia; Humans; Insulin-Like Growth Factor I; Methylamines; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Vegans

Topics: Animals; Antineoplastic Agents; Enzyme Inhibitors; Gene Regulatory Networks; Humans; Neoplasms; Protein Structure, Secondary; Sarcoplasmic Reticulum Calcium-Transporting ATPases

FK506 binding (FKBP) proteins are part of the highly conserved immunophilin family and its members have fundamental roles in the regulation of signalling pathways involved in inflammation, adaptive immune responses, cancer and developmental biology. The original member of this family, FKBP12, is a well-known binding partner for the immunosuppressive drugs tacrolimus (FK506) and sirolimus (rapamycin). FKBP12 and its analog, FKBP12.6, function as cis/trans peptidyl prolyl isomerases (PPIase) and they catalyse the interconversion of cis/trans prolyl conformations. Members of this family uniquely contain a PPIase domain, which may not be functional. The larger FKBPs, such as FKBP51, FKBP52 and FKBPL, contain extra regions, including tetratricopeptide repeat (TPR) domains, which are important for their versatile protein-protein interactions with inflammation-related signalling pathways. In this review we focus on the pivotal role of FKBP proteins in regulating glucocorticoid signalling, canonical and non-canonical NF-κB signalling, mTOR/AKT signalling and TGF-β signalling. We examine the mechanism of action of FKBP based immunosuppressive drugs on these cell signalling pathways and how off target interactions lead to the development of side effects often seen in the clinic. Finally, we discuss the latest advances in the role of FKBPs as therapeutic targets and the development of novel agents for a range of indications of unmet clinical need, including glucocorticoid resistance, obesity, stress-induced inflammation and novel cancer immunotherapy.

Topics: Animals; Drug Development; Humans; Immunosuppressive Agents; Inflammation; Neoplasms; Signal Transduction; Sirolimus; Tacrolimus; Tacrolimus Binding Proteins

Anticancer agents are critical for the cancer treatment, but side effects and the drug resistance associated with the currently used anticancer agents create an urgent need to explore novel drugs with low side effects and high efficacy. 1,2,3-Triazole is privileged building block in the discovery of new anticancer agents, and some of its derivatives have already been applied in clinics or under clinical trials for fighting against cancers. Hybrid molecules occupy an important position in cancer control, and hybridization of 1,2,3-triazole framework with other anticancer pharmacophores may provide valuable therapeutic intervention for the treatment of cancer, especially drug-resistant cancer. This review emphasizes the recent advances in 1,2,3-triazole-containing hybrids with anticancer potential, covering articles published between 2015 and 2019, and the structure-activity relationships, together with mechanisms of action are also discussed.

Topics: Antineoplastic Agents; Humans; Molecular Structure; Neoplasms; Structure-Activity Relationship; Triazoles

The review describes the experimental and clinical data of the last decades on the use of geroprotective preparations of mTOR inhibitors group for the main and accompanying treatment of cancer patients. mTOR protein kinase is an perspective therapeutic target for the treatment of multiple cancers, both with the mTOR inhibitors themselves (rapamycin and its derivatives) and in combination with inhibitors of other pathways (for example, metformin). The mTOR inhibitors, not being classical cytostatics and not having carcinogenic activity, have great prospects for use both as independent antitumor agents and for use in combination with conventional chemotherapy.. В обзоре рассмотрены экспериментальные и клинические данные последних десятилетий о применении геропротекторных препаратов группы ингибиторов mTOR для основного и сопроводительного лечения онкологических пациентов. Протеинкиназа mTOR представляет собой интересную терапевтическую мишень для лечения множественных видов рака как с помощью самих ингибиторов mTOR (рапамицина и его производных), так и в комбинации с ингибиторами других путей (например, метформина). Ингибиторы mTOR, не являясь классическими цитостатиками и не обладая канцерогенной активностью, имеют большие перспективы использования как в качестве самостоятельных противоопухолевых агентов, так и для применения в сочетании с конвенциональной химиотерапией.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Humans; Metformin; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Mechanistic target of rapamycin (mTOR) is the kinase subunit of two structurally and functionally distinct large multiprotein complexes, referred to as mTOR complex 1 (mTORC1) and mTORC2. mTORC1 and mTORC2 play key physiological roles as they control anabolic and catabolic processes in response to external cues in a variety of tissues and organs. However, mTORC1 and mTORC2 activities are deregulated in widespread human diseases, including cancer. Cancer cells take advantage of mTOR oncogenic signaling to drive their proliferation, survival, metabolic transformation, and metastatic potential. Therefore, mTOR lends itself very well as a therapeutic target for innovative cancer treatment. mTOR was initially identified as the target of the antibiotic rapamycin that displayed remarkable antitumor activity

Topics: Antibiotics, Antineoplastic; Cell Proliferation; Drug Discovery; Humans; Molecular Targeted Therapy; Neoplasms; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

mTOR-4E-BP1 axis is regarded as the best oncogenic circuitry impinging on translational control whereby mTORC1 dictates post-translational regulation of 4E-BP1. This review provides new insights into the molecular network of signalling pathways highlighting the recent explosion of studies in respect to the deviant behaviour of 4E-BP1 towards mTORC1. Despite the striking conservation of mTOR nexus, the eccentric phosphorylation dynamics of 4E-BP1 negate the apparent linear architecture of mTORC1 attesting the importance of other kinases that may evoke cross-talks with the conventional frame, most of which are enlisted in the manuscript. We also throw light on the tenuous role of rapamycin in 4E-BP1 regulation, which further necessitates the evaluation of 4E-BP1 to envisage the underlying molecular mechanisms in the discovery of novel drugs of 4E-BP1 for new treatment strategies. Finally, the review brings forward comprehensive studies delineating the redundancy of 4E-BP isoforms in regulating translational control.

Topics: Adaptor Proteins, Signal Transducing; Animals; Antibiotics, Antineoplastic; Cell Cycle Proteins; Cell Transformation, Neoplastic; Gene Expression Regulation, Neoplastic; Humans; Mechanistic Target of Rapamycin Complex 1; Neoplasms; Phosphoproteins; Phosphorylation; Protein Biosynthesis; Protein Isoforms; Protein Processing, Post-Translational; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is a central controller of cell growth, proliferation, metabolism, and angiogenesis. This protein is an attractive target for new anticancer drug development. Significant progress has been made in hit discovery, lead optimization, drug candidate development and determination of the three-dimensional (3D) structure of mTOR. Computational methods have been applied to accelerate the discovery and development of mTOR inhibitors helping to model the structure of mTOR, screen compound databases, uncover structure-activity relationship (SAR) and optimize the hits, mine the privileged fragments and design focused libraries. Besides, computational approaches were also applied to study protein-ligand interactions mechanisms and in natural product-driven drug discovery. Herein, we survey the most recent progress on the application of computational approaches to advance the discovery and development of compounds targeting mTOR. Future directions in the discovery of new mTOR inhibitors using computational methods are also discussed.

Topics: Adenosine Triphosphate; Antineoplastic Agents; Drug Discovery; Humans; Molecular Docking Simulation; Neoplasms; Quantitative Structure-Activity Relationship; Sirolimus; TOR Serine-Threonine Kinases

The phosphoinositide 3-kinase (PI3K) pathway is an intracellular signaling pathway that has regulatory roles in cell survival, proliferation, and differentiation, and a critical role in tumorigenesis. In cancer, multiple studies have investigated the therapeutic targeting of the PI3K pathway, and multiple inhibitors targeting PI3K and its isoforms, protein kinase B/AKT, mammalian target of rapamycin (mTOR), and other pathway proteins have been developed. For the treatment of solid tumors, only allosteric mTOR inhibitors, such as everolimus and temsirolimus, are currently approved for clinical use. This review describes the PI3K inhibitors that have progressed from the laboratory to late-stage clinical trials, and discusses the challenges that have prevented other compounds from doing the same. Challenges to the therapeutic effectiveness of some PI3K inhibitors include the absence of reliable and effective biomarkers, their limited efficacy as single agents, insufficient development of rational therapeutic combinations, the use of schedules with a variety of off-target effects, and suboptimal therapeutic exposures. Therefore, with regard to PI3K inhibitors currently in late-stage clinical trials, the identification of appropriate biomarkers of efficacy and the development of optimal combination regimens and dosing schedules are likely to be important for graduation into clinical practice.

Topics: Animals; Clinical Trials, Phase II as Topic; Drug Approval; Everolimus; Female; Follow-Up Studies; Humans; Male; Molecular Targeted Therapy; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; Survival Analysis; Treatment Outcome; United States; United States Food and Drug Administration

Autophagy is an essential catabolic program that forms part of the stress response and enables cells to break down their own intracellular components within lysosomes for recycling. Accumulating evidence suggests that autophagy plays vital roles in determining pathological outcomes of immune responses and tumorigenesis. Autophagy regulates innate and adaptive immunity affecting the pathologies of infectious, inflammatory, and autoimmune diseases. In cancer, autophagy appears to play distinct roles depending on the context of the malignancy by either promoting or suppressing key determinants of cancer cell survival. This review covers recent developments in the understanding of autophagy and discusses potential therapeutic interventions that may alter the outcomes of certain diseases.

Topics: Adaptive Immunity; Animals; Autoimmune Diseases; Autophagy; Benzylisoquinolines; Cholecalciferol; Humans; Immune System Diseases; Immunity, Innate; Indoles; Infections; Isoquinolines; Lysosomes; Maprotiline; Metformin; Neoplasms; Phenols; Pyrroles; Resveratrol; Sirolimus; Spermidine; Stilbenes; Tetrahydroisoquinolines; Trehalose

The prevalence of obesity, of type 2 diabetes mellitus (T2DM), and of cancer are all increasing globally. The relationships between these diseases are complex, and thus difficult to elucidate; nevertheless, evidence supports the hypothesis that obesity increases the risks of both T2DM and certain cancers. Further complexity arises from controversial evidence that specific drugs used in the treatment of T2DM increase or decrease cancer risk or influence cancer prognosis. Herein, we review the current evidence from studies that have addressed these relationships, and summarize the methodological challenges that are frequently encountered in such research. We also outline the physiology that links obesity, T2DM, and neoplasia. Finally, we outline the practical principles relevant to the increasingly common challenge of managing patients who have been diagnosed with both diabetes and cancer.

Topics: Androgen Antagonists; Antineoplastic Agents; Diabetes Mellitus, Type 2; Global Health; Glucocorticoids; Humans; Hypoglycemic Agents; Incidence; Insulin; Neoplasms; Obesity; Prevalence; Prognosis; Risk Factors; Signal Transduction; Sirolimus; Survivors

Macroautophagy (hereafter called autophagy) is a vacuolar, lysosomal pathway for catabolism of intracellular material that is conserved among eukaryotic cells. Autophagy plays a crucial role in tissue homeostasis, adaptation to stress situations, immune responses, and the regulation of the inflammatory response. Blockade or uncontrolled activation of autophagy is associated with cancer, diabetes, obesity, cardiovascular disease, neurodegenerative disease, autoimmune disease, infection, and chronic inflammatory disease. During the past decade, researchers have made major progress in understanding the three levels of regulation of autophagy in mammalian cells: signaling, autophagosome formation, and autophagosome maturation and lysosomal degradation. As we discuss in this review, each of these levels is potentially druggable, and, depending on the indication, may be able to stimulate or inhibit autophagy. We also summarize the different modulators of autophagy and their potential and limitations in the treatment of life-threatening diseases.

Topics: Animals; Autophagy; Clinical Trials as Topic; Humans; Lysosomes; Neoplasms; Neurodegenerative Diseases; Signal Transduction; Sirolimus

Middle East Respiratory Syndrome (MERS) is a novel respiratory illness firstly reported in Saudi Arabia in 2012. It is caused by a new corona virus, called MERS corona virus (MERS-CoV). Most people who have MERS-CoV infection developed severe acute respiratory illness.. This work is done to determine the clinical characteristics and the outcome of intensive care unit (ICU) admitted patients with confirmed MERS-CoV infection.. This study included 32 laboratory confirmed MERS corona virus infected patients who were admitted into ICU. It included 20 (62.50%) males and 12 (37.50%) females. The mean age was 43.99 ± 13.03 years. Diagnosis was done by real-time reverse transcription polymerase chain reaction (rRT-PCR) test for corona virus on throat swab, sputum, tracheal aspirate, or bronchoalveolar lavage specimens. Clinical characteristics, co-morbidities and outcome were reported for all subjects.. Most MERS corona patients present with fever, cough, dyspnea, sore throat, runny nose and sputum. The presence of abdominal symptoms may indicate bad prognosis. Prolonged duration of symptoms before patients' hospitalization, prolonged duration of mechanical ventilation and hospital stay, bilateral radiological pulmonary infiltrates, and hypoxemic respiratory failure were found to be strong predictors of mortality in such patients. Also, old age, current smoking, smoking severity, presence of associated co-morbidities like obesity, diabetes mellitus, chronic heart diseases, COPD, malignancy, renal failure, renal transplantation and liver cirrhosis are associated with a poor outcome of ICU admitted MERS corona virus infected patients.. Plasma HO-1, ferritin, p21, and NQO1 were all elevated at baseline in CKD participants. Plasma HO-1 and urine NQO1 levels each inversely correlated with eGFR (. SnPP can be safely administered and, after its injection, the resulting changes in plasma HO-1, NQO1, ferritin, and p21 concentrations can provide information as to antioxidant gene responsiveness/reserves in subjects with and without kidney disease.. A Study with RBT-1, in Healthy Volunteers and Subjects with Stage 3-4 Chronic Kidney Disease, NCT0363002 and NCT03893799.. HFNC did not significantly modify work of breathing in healthy subjects. However, a significant reduction in the minute volume was achieved, capillary [Formula: see text] remaining constant, which suggests a reduction in dead-space ventilation with flows > 20 L/min. (ClinicalTrials.gov registration NCT02495675).. 3 组患者手术时间、术中显性失血量及术后 1 周血红蛋白下降量比较差异均无统计学意义（. 对于肥胖和超重的膝关节单间室骨关节炎患者，采用 UKA 术后可获满意短中期疗效，远期疗效尚需进一步随访观察。.. Decreased muscle strength was identified at both time points in patients with hEDS/HSD. The evolution of most muscle strength parameters over time did not significantly differ between groups. Future studies should focus on the effectiveness of different types of muscle training strategies in hEDS/HSD patients.. These findings support previous adverse findings of e-cigarette exposure on neurodevelopment in a mouse model and provide substantial evidence of persistent adverse behavioral and neuroimmunological consequences to adult offspring following maternal e-cigarette exposure during pregnancy. https://doi.org/10.1289/EHP6067.. This RCT directly compares a neoadjuvant chemotherapy regimen with a standard CROSS regimen in terms of overall survival for patients with locally advanced ESCC. The results of this RCT will provide an answer for the controversy regarding the survival benefits between the two treatment strategies.. NCT04138212, date of registration: October 24, 2019.. Results of current investigation indicated that milk type and post fermentation cooling patterns had a pronounced effect on antioxidant characteristics, fatty acid profile, lipid oxidation and textural characteristics of yoghurt. Buffalo milk based yoghurt had more fat, protein, higher antioxidant capacity and vitamin content. Antioxidant and sensory characteristics of T. If milk is exposed to excessive amounts of light, Vitamins B. The two concentration of ZnO nanoparticles in the ambient air produced two different outcomes. The lower concentration resulted in significant increases in Zn content of the liver while the higher concentration significantly increased Zn in the lungs (p < 0.05). Additionally, at the lower concentration, Zn content was found to be lower in brain tissue (p < 0.05). Using TEM/EDX we detected ZnO nanoparticles inside the cells in the lungs, kidney and liver. Inhaling ZnO NP at the higher concentration increased the levels of mRNA of the following genes in the lungs: Mt2 (2.56 fold), Slc30a1 (1.52 fold) and Slc30a5 (2.34 fold). At the lower ZnO nanoparticle concentration, only Slc30a7 mRNA levels in the lungs were up (1.74 fold). Thus the two air concentrations of ZnO nanoparticles produced distinct effects on the expression of the Zn-homeostasis related genes.. Until adverse health effects of ZnO nanoparticles deposited in organs such as lungs are further investigated and/or ruled out, the exposure to ZnO nanoparticles in aerosols should be avoided or minimised.

Topics: A549 Cells; Acetylmuramyl-Alanyl-Isoglutamine; Acinetobacter baumannii; Acute Lung Injury; Adaptor Proteins, Signal Transducing; Adenine; Adenocarcinoma; Adipogenesis; Administration, Cutaneous; Administration, Ophthalmic; Adolescent; Adsorption; Adult; Aeromonas hydrophila; Aerosols; Aged; Aged, 80 and over; Aging; Agriculture; Air Pollutants; Air Pollution; Airway Remodeling; Alanine Transaminase; Albuminuria; Aldehyde Dehydrogenase 1 Family; Algorithms; AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase; Alzheimer Disease; Amino Acid Sequence; Ammonia; Ammonium Compounds; Anaerobiosis; Anesthetics, Dissociative; Anesthetics, Inhalation; Animals; Anti-Bacterial Agents; Anti-HIV Agents; Anti-Infective Agents; Anti-Inflammatory Agents; Antibiotics, Antineoplastic; Antibodies, Antineutrophil Cytoplasmic; Antibodies, Monoclonal, Humanized; Antifungal Agents; Antigens, Bacterial; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Antimetabolites, Antineoplastic; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Antioxidants; Antitubercular Agents; Antiviral Agents; Apolipoproteins E; Apoptosis; Arabidopsis; Arabidopsis Proteins; Arsenic; Arthritis, Rheumatoid; Asthma; Atherosclerosis; ATP-Dependent Proteases; Attitude of Health Personnel; Australia; Austria; Autophagy; Axitinib; Bacteria; Bacterial Outer Membrane Proteins; Bacterial Proteins; Bacterial Toxins; Bacterial Typing Techniques; Bariatric Surgery; Base Composition; Bayes Theorem; Benzoxazoles; Benzylamines; beta Catenin; Betacoronavirus; Betula; Binding Sites; Biological Availability; Biological Oxygen Demand Analysis; Biomarkers; Biomarkers, Tumor; Biopsy; Bioreactors; Biosensing Techniques; Birth Weight; Blindness; Blood Chemical Analysis; Blood Gas Analysis; Blood Glucose; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Blood-Brain Barrier; Blotting, Western; Body Mass Index; Body Weight; Bone and Bones; Bone Density; Bone Resorption; Borates; Brain; Brain Infarction; Brain Injuries, Traumatic; 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The evolutionarily conserved mechanistic target of rapamycin (mTOR) forms two functionally distinct complexes, mTORC1 and mTORC2. mTORC1, consisting of mTOR, raptor, and mLST8 (GβL), is sensitive to rapamycin and thought to control autonomous cell growth in response to nutrient availability and growth factors. mTORC2, containing the core components mTOR, mLST8, Rictor, mSIN1, and Protor1/2 is largely insensitive to rapamycin. mTORC2 specifically senses growth factors and regulates cell proliferation, metabolism, actin rearrangement, and survival. Dysregulation of mTOR signaling often occurs in a variety of human malignant diseases, rendering it a crucial and validated target in cancer treatment. However, the effectiveness of rapamycin as single-agent therapy is suppressed, in part, by the numerous strong mTORC1-dependent negative feedback loops. Although preclinical and clinical studies of ATP-competitive mTOR inhibitors that target both mTORC1 and mTORC2 have shown greater effectiveness than rapalogs for cancer treatment, the mTORC1 inhibition-induced negative feedback activation of PI3- K/PDK1 and Akt (Thr308) may be sufficient to promote cell survival. Recent cancer biology studies indicated that mTORC2 is a promising target, since its activity is essential for the development of a number of cancers. These studies provide a rationale for developing inhibitors specifically targeting mTORC2, which do not perturb the mTORC1- dependent negative feedback loops and have a more acceptable therapeutic window. This review summarizes the present understanding of mTORC2 signaling and functions, especially tumorigenic functions, highlighting the current status and future perspectives for targeting mTORC2 in cancer treatment.

Topics: Animals; Antineoplastic Agents; Carrier Proteins; Humans; Mechanistic Target of Rapamycin Complex 2; Multiprotein Complexes; Neoplasms; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The translation initiation factor eIF4E mediates a rate-limiting process that drives selective translation of many oncongenic proteins such as cyclin D1, survivin and VEGF, thereby contributing to tumour growth, metastasis and therapy resistance. As an essential regulatory hub in cancer signalling network, many oncogenic signalling pathways appear to converge on eIF4E. Therefore, targeting eIF4E-mediated cap-dependent translation is considered a promising anticancer strategy. This paper reviews the strategies that can be used to target eIF4E, highlighting agents that target eIF4E activity at each distinct level.

Topics: Animals; Antineoplastic Agents; Cyclin D1; Epoxy Compounds; Eukaryotic Initiation Factor-4E; Gene Expression Regulation, Neoplastic; Humans; Inhibitor of Apoptosis Proteins; Macrolides; Neoplasms; Oligonucleotides, Antisense; Protein Biosynthesis; Ribavirin; RNA, Small Interfering; Signal Transduction; Sirolimus; Survivin; Thiazoles; Triterpenes; Vascular Endothelial Growth Factor A

The mTOR pathway is a critical regulator of cell growth, proliferation, metabolism, and survival. Dysregulation of mTOR signaling has been observed in most cancers and, thus, the mTOR pathway has been extensively studied for therapeutic intervention. Rapamycin is a natural product that inhibits mTOR with high specificity. However, its efficacy varies by dose in several contexts. First, different doses of rapamycin are needed to suppress mTOR in different cell lines; second, different doses of rapamycin are needed to suppress the phosphorylation of different mTOR substrates; and third, there is a differential sensitivity of the two mTOR complexes mTORC1 and mTORC2 to rapamycin. Intriguingly, the enigmatic properties of rapamycin dosage can be explained in large part by the competition between rapamycin and phosphatidic acid (PA) for mTOR. Rapamycin and PA have opposite effects on mTOR whereby rapamycin destabilizes and PA stabilizes both mTOR complexes. In this review, we discuss the properties of rapamycin dosage in the context of anticancer therapeutics.

Topics: Animals; Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Drug Resistance, Neoplasm; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Multiprotein Complexes; Neoplasms; Protein Binding; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The risk of infection attributable to mTOR inhibitors has not been determined. Databases from PubMed and abstracts presented at the American Society of Clinical Oncology meetings were searched. Eligible studies included randomized controlled trials, in which everolimus or temsirolimus was compared with placebo. A total of 12 trials were included. The attributable incidences of all-grade and high-grade infections to mTOR inhibitors were 9.3% (95% confidence interval (CI): 5.8-14.6%) and 2.3% (95% CI: 1.2-4.4%) respectively. The risk varied widely with tumor types (p <.001). There was substantial risk of infection attributable to mTOR inhibitors everolimus and temsirolimus.

Topics: Antineoplastic Combined Chemotherapy Protocols; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Everolimus; Humans; Incidence; Infections; Neoplasms; Odds Ratio; Protein Kinase Inhibitors; Randomized Controlled Trials as Topic; Risk; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR) inhibitors, everolimus and temsirolimus, are approved for the treatment of a variety of malignancies. Fatigue has been described with these agents as a common side effect, although the overall incidence and risk remain unclear. We performed a meta-analysis to calculate the overall incidence of fatigue in cancer patients treated with everolimus and temsirolimus and to compare the differences in incidence with placebo. The electronic databases PubMed, Embase, Web of Science, and Cochrane databases were searched for studies to include in the meta-analysis. Eligible studies were phase II and III prospective clinical trials of cancer patients treated with single drug everolimus or temsirolimus with toxicity data on fatigue. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated employing fixed or random effects models depending on the heterogeneity of the included studies. A total of 9,760 patients with a variety of malignancies from 56 prospective clinical trials were included for the meta-analysis. The overall incidences of all-grade and high-grade fatigue in cancer patients treated with mTOR inhibitor (everolimus or temsirolimus) were 45.4% (95% CI 36.9-55.8%) and 8.7% (95% CI 7.2-10.4%), respectively. The relative risks of fatigue of mTOR inhibitor compared to placebo were increased for all-grade (RR = 1.22, 95% CI 1.08-1.38, P = 0.002) and high-grade (RR = 1.82, 95% CI 1.24-2.69, P = 0.002) fatigue. The incidence of all-grade fatigue of patients treated with everolimus was higher than those with temsirolimus (RR = 1.85, 95% CI 1.71-2.01, P < 0.001). No significant difference was detected with between everolimus and temsirolimus in terms of high-grade fatigue (RR = 1.15, 95% CI 0.94-1.41, P = 0.18). Treatment with mTOR inhibitor, everolimus and temsirolimus, is associated with an increased incidence of fatigue in patients with cancer. Early detection and management of fatigue is needed.

Topics: Clinical Trials as Topic; Everolimus; Fatigue; Humans; Neoplasms; Prospective Studies; Protein Kinase Inhibitors; Risk; Sirolimus; TOR Serine-Threonine Kinases

We performed a systematic review and meta-analysis of fatigue, hepatic and metabolic toxicities associated with everolimus intake in patients with solid tumors.. Eligible studies included randomized trials of patients with solid tumors on everolimus describing events of fatigue, hyperlipidemia, hyperglycemia and elevated alanine aminotransferase (ALT).. After the exclusion of ineligible studies, a total of ten clinical trials were considered eligible for the meta-analysis. The relative risks of all-grade fatigue, hyperglycemia, hyperlipidemia and elevated ALT were 1.31 (p < 0.002), 3.06 (p < 0.0001), 2.54 (p = 0.0001) and 2.96 (p < 0.003), respectively.. Our meta-analysis demonstrates that everolimus is associated with a significantly increased risk of all-grade fatigue, hyperglycemia, hyperlipidemia and elevated ALT.

Topics: Chemical and Drug Induced Liver Injury; Everolimus; Fatigue; Humans; Neoplasms; Protein Kinase Inhibitors; Risk Factors; Sirolimus

Inhibitors of the mammalian target of rapamycin (mTOR) pathway including everolimus and temsirolimus have been used extensively in cancer patients. Their use is associated with stomatitis, an adverse event resulting in morbidity and treatment interruptions or discontinuation. This study was conducted to determine the overall incidence and risk of stomatitis in cancer patients treated with the mTOR inhibitors by a meta-analysis of randomized controlled clinical trials (RCTs).. Databases from PubMed and abstracts presented at the American Society of Clinical Oncology annual meetings up to October 2013 were searched for relevant studies. Eligible studies included RCTs using everolimus and temsirolimus at approved doses in cancer patients. Summary incidences, relative risks (RR), and 95% confidence intervals (CI) were calculated using a random- or fixed-effects model depending on the heterogeneity of the included trials.. A total of 11 RCTs with 4,752 patients (mTORs: 2,725, controls: 2,027) with a variety of solid tumors were included in the analysis. The incidences of all-grade (grade 1-4) and high-grade stomatitis (grade 3-4) were 33.5% (95% CI: 21.9-47.6%) and 4.1% (95% CI: 2.6-6.3%), respectively. The incidence of high-grade stomatitis significantly varied with tumor types (p=.004), and mTOR inhibitors (temsirolimus vs. everolimus, p<.001). In comparison with controls, mTOR inhibitors significantly increased the risk for developing all-grade stomatitis (RR: 4.04, 95% CI: 3.13-5.22, p<.001) and high-grade stomatitis (RR: 8.84, 95% CI: 4.07-19.22, p<.001).. The mTOR inhibitors everolimus and temsirolimus significantly increased the risk of high-grade stomatitis in cancer patients. Efforts towards the prevention, treatment, and identification of individuals at risk may allow for improved quality of life and consistent dosing.

Topics: Everolimus; Humans; Incidence; Neoplasms; Randomized Controlled Trials as Topic; Risk Factors; Sirolimus; Stomatitis; TOR Serine-Threonine Kinases

We performed a meta-analysis of fatigue associated with the use of everolimus, temsirolimus or ridaforolimus in patients with solid tumors. Eligible studies included randomized trials of patients with solid tumors on everolimus, temsirolimus or ridaforolimus describing events of fatigue. A total of 18 clinical trials including 8143 patients were considered eligible for the meta-analysis. On the basis of random-effects model, we found that the relative risk of all-grade and high-grade fatigue were 1.26 [95% CI: 1.09-1.46; p < 0.0001], 1.49 [95% CI: 0.99, 2.24; p = 0.05], respectively. On subgroup analysis, we cannot identify any difference between everolimus and temsirolimus in the risk of fatigue. Thus, our meta-analysis has demonstrated that regimens containing everolimus, temsirolimus or ridaforolimus for the treatment of solid tumors are associated with an increased risk of all-grade fatigue, whereas the risk of high-grade fatigue did not reach the threshold of statistical significance. Close clinical monitoring and pre-emptive treatment for fatigue are recommended.

Topics: Antineoplastic Agents; Everolimus; Fatigue; Humans; Neoplasms; Protein Kinase Inhibitors; Randomized Controlled Trials as Topic; Risk; Sirolimus

Diabetes mellitus is a metabolic homeostasis disease that contributes to additional comorbidities such as cardiovascular disease (CVD) and cancer. It has a long undiagnosed latent period during which there can be irreparable damage to the pancreas and cardiovascular tissues. Recent studies have highlighted the roles of several microRNAs in CVD. Determining the microRNAs that link diabetes mellitus and CVD is an important topic to be explored. In the present review, we discuss the microRNAs that contribute to the progression of diabetes mellitus and CVD and focus on the miR-29 family microRNAs whose expression is upregulated by hyperglycemia and proinflammatory cytokines, the hallmarks of diabetes mellitus. Upregulation of miR-29 expression is a key factor in the loss of pancreatic β cells and development of the first stage of type 1 diabetes mellitus (T1DM). Additionally, miR-29-mediated suppression of myeloid cell leukemia 1 (MCL-1), an important prosurvival protein, underlies Marfan's syndrome, abdominal aortic aneurysm, and diabetes mellitus-associated cardiomyocyte disorganization. Suppression of miR-29 expression and subsequent increase in the prosurvival MCL-1, however, promotes tumor development. Therefore, miR-29 mimics that suppress MCL-1 are hailed as tumor suppressors. The critical question is whether an increase in miR-29 levels is well tolerated in conditions of comorbidities in which insulin resistance is an underlying disease. In light of increasing awareness of the interconnection of diabetes mellitus, CVD, and cancer, it is of utmost importance to understand the mechanism of action of current treatment options on all of the comorbidities and careful evaluation of cardiovascular toxicity must accompany any treatment paradigm that increases miR-29 levels.

Topics: Animals; Cardiovascular Diseases; Diabetes Complications; Diabetes Mellitus; Diabetic Angiopathies; Gene Expression Regulation; Genetic Predisposition to Disease; Humans; Immunosuppressive Agents; MicroRNAs; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasms; Sirolimus

Everolimus, an inhibitor of mammalian target of rapamycin (mTOR) used for the treatment of various solid tumors, is associated with anemia, which can lead to morbidity and treatment interruption or discontinuation. Because the underlying causes of anemia can be multifactorial, we performed a meta-analysis of randomized controlled trials (RCTs) to determine the overall risk of anemia specifically attributable to everolimus in cancer patients.. We searched the PubMed database and abstracts presented at the American Society of Clinical Oncology annual meetings up to May 2014 for relevant studies. Eligible studies included RCTs in which everolimus alone or in combination with other agents was compared to placebo alone or with other agents in patients with cancer. Summary incidences, relative risks (RR), and 95% confidence intervals (CI) were calculated using a random- or fixed-effects model depending on the heterogeneity of the included trials. The attributable risk was determined by the incidence with everolimus minus that without everolimus in controls.. A total of nine RCTs with 3,678 patients (everolimus, n=2,162; controls, n=1,516) were included in our analysis. In comparison with controls, everolimus significantly increased the risk of all-grade (RR=2.18, 95% CI=1.56-3.04, p<0.001) and high-grade anemia (RR=2.63, 95% CI=1.35-5.15, p<0.001). The summary incidences of all-grade (grades 1-4) and high-grade (grades 3-4) anemia in patients treated with everolimus were 32.1% (95% CI=17.5-51.3%) and 6.9% (95% CI=4.1-11.3%) respectively, with 13.3% (95% CI=10.0-17.5%) and 4.7% (95% CI=2.8-7.7%) specifically attributable to everolimus. Risk factors of high-grade anemia attributable to everolimus included tumor type (p=0.012), with the highest seen in renal cell carcinoma (8.0%, 95% CI=5.3-11.9%), and chemotherapy (p<0.001).. There is a substantial risk of all-grade and high-grade anemia attributable to everolimus therapy for cancer.

Topics: Anemia; Antineoplastic Agents; Everolimus; Humans; Neoplasms; PubMed; Randomized Controlled Trials as Topic; Risk Factors; Sirolimus; TOR Serine-Threonine Kinases

The mechanistic target of rapamycin (mTOR) is a ubiquitous serine/threonine kinase, which plays pivotal roles in integrating growth signals on a cellular level. To support proliferation and survival under stress, two interacting complexes that harbor mTOR, mTORC1 and mTORC2, promote the transcription of genes involved in carbohydrate metabolism and lipogenesis, enhance protein translation, and inhibit autophagy. Although rapamycin was originally developed as an inhibitor of T cell proliferation for preventing organ transplant rejection, its molecular target, mTOR, has been subsequently identified as a central regulator of metabolic cues that drive lineage specification in the immune system. Owing to oxidative stress, the activation of mTORC1 has emerged as a central pathway for the pathogenesis of systemic lupus erythematosus and other autoimmune diseases. Paradoxically, mTORC1 has also been identified as a mediator of the Warburg effect that allows cell survival under hypoxia. Rapamycin and new classes of mTOR inhibitors are being developed to block not only transplant rejection and autoimmunity but also to treat obesity and various forms of cancer. Through preventing these diseases, personalized mTOR blockade holds promise to extend life span.

Topics: Aging; Animals; Autoimmune Diseases; Biomarkers; Humans; Neoplasms; Obesity; Precision Medicine; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Protein-protein interactions (PPI) are at the center of molecular mechanisms of life. The protein ligands convene for regulation of biological function: adding, enhancing or inhibiting activity, for assistance in structural integrity or to enable subsequent PPI. All these general roles of PPI are represented in the proteasome, the giant proteolytic factory universally present in human cells. The proteasome is a renowned target for anti-cancer drugs and a considered target for drugs curbing inflammation. The essential function of the proteasome, the degradation of a majority of intracellular proteins via the ubiquitin-proteasome pathway, relies on proper interactions between multiple subunits of the enzyme and between multiple modules forming distinct super-assemblies covered by the "proteasome" name. The interface regions between constitutive, alternative or transient protein components of the proteasome provide a rich platform for design of drugs with potentially very diverse actions. Still, the resource remains largely untapped since all proteasome-targeting drugs used so far in humans are classical competitive inhibitors blocking catalytic centers. In this review, we will discuss the opportunities and challenges of targeting PPI in the hub enzyme for intracellular protein catabolism, the proteasome.

Topics: Allosteric Regulation; Antineoplastic Agents; Bortezomib; Catalytic Domain; Drug Design; Humans; Ligands; Neoplasms; Oligopeptides; Peptides; Proteasome Endopeptidase Complex; Protein Binding; Protein Interaction Domains and Motifs; Protein Interaction Mapping; Sirolimus; Structure-Activity Relationship

The authors performed a systematic review and meta-analysis of diarrhea and stomatitis associated with the use of everolimus, temsirolimus or ridaforolimus in patients with solid tumors.. Eligible studies included randomized trials of patients with solid tumors on everolimus, temsirolimus or ridaforolimus, describing the events of diarrhea and stomatitis.. After exclusion of ineligible studies, a total of 18 clinical trials including 8143 patients were considered eligible for the meta-analysis. The relative risk ratios of all-grade diarrhea and stomatitis were 1.94 (95% CI: 1.6-2.36; p < 0.00001) and 3.54 (95% CI: 2.59-4.84; p < 0.00001), respectively, while the relative risk ratios of high-grade diarrhea and stomatitis were 3.49 (95% CI: 2.39-5.09; p < 0.00001) and 6.98 (95% CI: 4.76-10.26; p < 0.00001), respectively. On subgroup analysis, there was no statistically significant difference between everolimus and temsirolimus in the risk of relevant adverse events.. This meta-analysis demonstrated that regimens containing everolimus, temsirolimus or ridaforolimus for the treatment of solid tumors are associated with a significantly increased risk of all-grade and high-grade diarrhea and stomatitis. Close clinical monitoring is required when administering these drugs.

Topics: Antineoplastic Agents; Diarrhea; Everolimus; Humans; Intestinal Mucosa; Mouth Mucosa; Neoplasms; Sirolimus; Stomatitis

The common dysregulation of the mTOR signaling pathway in tumor cells makes it a key target in oncotherapy. To better understand the effects of mTOR inhibitors, we analyzed 32 published clinical trials on solid tumors other than renal cell cancer, neuroendocrine tumors and metastatic breast cancer, for mTOR inhibitors are already approved by the US FDA to treat the three cancers. A lack of therapeutic effects was observed when mTOR inhibitors were used as a single agent. When combined with other agents, mTOR inhibitors still lacked sufficient clinical activity or just had minimal activity. More studies are required to better understand the clinically effects of mTOR inhibitors and the development of novel mTOR inhibitors is absolutely necessary.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Clinical Trials as Topic; Docetaxel; Erlotinib Hydrochloride; Everolimus; Gefitinib; Humans; Imatinib Mesylate; Neoplasms; Protein Kinase Inhibitors; Quinazolines; Signal Transduction; Sirolimus; Taxoids; TOR Serine-Threonine Kinases

Sirolimus, an immunosuppressant option for kidney transplant recipients, may reduce cancer risk by interrupting the mammalian target of rapamycin pathway. However, studies of sirolimus and cancer incidence in kidney recipients have not been definitive, and have had limited ability to examine specific cancer types. The literature was systematically reviewed to identify randomized controlled trials (RCTs) and observational studies of kidney recipients that compared sirolimus users to sirolimus nonusers. Meta-analytic methods were used to obtain pooled estimates of the association between sirolimus use and incidence of total cancer and specific cancer types. Estimates were stratified by study type (RCT vs. observational) and use of cyclosporine (an immunosuppressant that affects DNA repair). Twenty RCTs and two observational studies were eligible for meta-analysis, including 39,039 kidney recipients overall. Sirolimus use was associated with lower overall cancer incidence (incidence rate ratio [IRR] = 0.71, 95% CI = 0.56-0.90), driven by a reduction in incidence of nonmelanoma skin cancer (NMSC, IRR = 0.49, 95% CI = 0.32-0.76). The protective effect of sirolimus on NMSC risk was most notable in studies comparing sirolimus against cyclosporine (IRR = 0.19, 95% CI = 0.04-0.84). After excluding NMSCs, there was no overall association between sirolimus and incidence of other cancers (IRR = 1.06, 95% CI = 0.69-1.63). However, sirolimus use had associations with lower kidney cancer incidence (IRR = 0.40, 95% CI = 0.20-0.81), and higher prostate cancer incidence (IRR = 1.85, 95% CI = 1.17-2.91). Among kidney recipients, sirolimus users have lower NMSC risk, which may be partly due to removal of cyclosporine. Sirolimus may also reduce kidney cancer risk but did not appear protective for other cancers, and it may actually increase prostate cancer risk.

Topics: Female; Humans; Immunosuppressive Agents; Incidence; Kidney Transplantation; Male; Neoplasms; Odds Ratio; Risk; Sirolimus; Transplant Recipients

Rapamycin has gained significant attention for its potential activity in reducing the size of TSC-associated tumors, thus providing alternative to surgery. This study aimed at determining the efficacy of rapamycin and rapalogs for reducing the size of TSC-associated solid tumors in patients with Tuberous Sclerosis Complex (TSC).. Our data sources included electronic searches of the PubMed. We included into our meta-analysis any type of non-randomized study that reported the use of rapamycin and rapalogs for reducing the size of TSC-associated solid tumors in patients with TSC. Data was entered into Cochrane Review Manager Version 5.3 and analyzed.. Four case reports and 4 clinical trials were included. Five patients from the case reports (all with SEGA) and 91 patients from the clinical trials (41 with SEGA, 63 with kidney angiomyolipoma and 5 with liver angiomyolipoma) were included into the analysis. Volume and diameter of SEGAs were significantly reduced by mean difference of 1.23 cc (95 % CI -2.32 to -0.13; p = 0.03) and 7.91 mm (95 % CI -11.82 to -4.01; p < 0.0001), respectively. Volume and mean of sum of longest diameter of kidney angiomyolipomas were significantly reduced by mean difference of 39.5 cc (95 % CI -48.85 to -30.15; p <0.00001) and 69.03 mm (95 % CI -158.05 to 12.65; p = 0.008), respectively. In liver angiomyolipomas, however, reduction in tumor size was not evident. Sum of longest diameter of liver angiomyolipomas in 4 patients were enlarged by 2.7 mm (95 % CI 28.42 to -23.02) by the end of treatment, though not significant (p = 0.84).. Rapamycin and rapalogs showed efficacy towards reducing the size of SEGA and kidney angiomyolipoma but not liver angiomyolipomas. This finding is strengthening the conclusion of our Cochrane systematic review on the randomized trials.

Topics: Adolescent; Adult; Female; Humans; Male; Neoplasms; Sirolimus; Tuberous Sclerosis; Young Adult

Rapamycin and its analogs (rapalogs) are the first generation of mTOR inhibitors, which have the same molecular scaffold, but different physiochemical properties. Rapalogs are being tested in a wide spectrum of human tumors as both monotherapy and a component of combination therapy. Among them, temsirolimus and everolimus have been approved for the treatment of breast and renal cancer. However, objective response rates with rapalogs in clinical trials are modest and variable. Identification of biomarkers predicting response to rapalogs, and discovery of drug combinations with improved efficacy and tolerated toxicity are critical to moving this class of targeted therapeutics forward. This review focuses on the aberrations in the PI3K/mTOR pathway in human tumor cells or tissues as predictive biomarkers for rapalog efficacy. Recent results of combinational therapy using rapalogs and other anticancer drugs are documented. With the rapid development of next-generation genomic sequencing and precision medicine, rapalogs will provide greater benefits to cancer patients.

Topics: Animals; Antibiotics, Antineoplastic; Computational Biology; Humans; Molecular Targeted Therapy; Neoplasms; Phosphatidylinositol 3-Kinases; Precision Medicine; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Macrophage is a key cell of immune system, it participates in antiviral, antimicrobial and antitumor defense of the organism, also in regeneration and reparation of tissues. Macrophage coordinates functioning of immune system, participates in tumor growth progression. The process of inflammation consists of two stages. Cytotoxical potential of immunocompetent cells will be realized in the first stage, to avoid a bacterial infection. The second stage of inflammatory process is associated with reparation and regeneration. During inflammation, according it stages, macrophages change functional state, switching from cytotoxical M1 to M2, that associated with reparation. We suppose, that rapamysin, a suppressor of mTOR, causes completely different effects on tumor associated macrophages and cells of microglia. Rapamycin transforms tissue macrophages into M1 phenotype, promoting the tumor regression. While in microglial cells of the central nervous system it induces transformation into M2 phenotype, facilitating the course of the neurodegenerative disease and slowing down the aging.

Topics: Animals; Bacterial Infections; Humans; Macrophages; Neoplasms; Neurodegenerative Diseases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Virus Diseases

mTOR inhibitors are now approved by regulatory agencies for the treatment of a variety of malignancies. The risk of metabolic complications with these agents is not well characterized.. PubMed was searched for articles published from 2001 until 2011. Eligible studies included prospective randomized trials evaluating temsirolimus, everolimus, and ridaforolimus in patients with all solid tumor malignancies. Sixteen eligible phase II clinical trials and 8 randomized controlled clinical trials were included in a systematic review and meta-analysis and the number of metabolic related AEs (hyperglycemia, hypercholesterolemia, and hypertriglyceridemia) was extracted. Incidence rates and incident rate ratios were calculated.. Twenty-four trials, including 4261 patients, were included in the calculation of the incidence rate. The average incidence rate of all grade metabolic related events was 0.70 (95% CI, 0.47, 0.93). The average incidence rate of serious (grade 3 and 4) metabolic related adverse events was 0.11 (95% CI, 0.08, 0.15). The incidence rate ratio (IRR) of a metabolic adverse event with mTOR inhibitor therapy compared with control was 2.93 (95% CI, 2.33, 3.70) and of serious grade 3 and 4 metabolic adverse events was 4.58 (95% CI, 2.86, 7.34). The IRR of all grade hyperglycemia was 2.95 (95% CI, 2.14, 4.05) and of grade 3-4 hyperglycemia was 5.25 (95% CI, 3.07, 9.00). The IRR of all grade hypertriglyceridemia was 2.49 (95% CI, 1.76, 3.52) and of grade 3-4 hypertriglyceridemia was 2.01 (95% CI, 0.65, 6.27). The IRR of all grade hypercholesterolemia was 3.35 (95% CI, 2.17, 5.18) and of grade 3-4 hypercholesterolemia was 6.51 (95% CI, 1.48, 28.59). These findings suggest a statistically significant increase in the risk of hyperglycemia, hypercholesterolemia (all grades and grade 3 and 4), and all grade hypertriglyceridemia associated with mTOR therapy when compared with control.. The risk of all grade and grade 3-4, hyperglycemia, hypercholesterolemia, and hypertriglyceridemia, are increase in patients treated with mTOR inhibitors compared with control.

Topics: Antibiotics, Antineoplastic; Dyslipidemias; Everolimus; Humans; Hyperglycemia; Incidence; Neoplasms; Randomized Controlled Trials as Topic; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR) inhibitors, temsirolimus and everolimus, are currently approved for the treatment of several malignancies. Hematological toxicities have been reported with these drugs, but overall incidence and relative risk remains undefined. We perform an up-to-date meta-analysis to determine the incidence and risk of hematologic toxicities associated with mTOR inhibitors.. Several databases were searched, including PubMed, Embase and Cochrane databases. Eligible studies included prospective phase II and III trials of temsirolimus and everolimus with adequate safety data profile reporting anemia, leucopenia, neutropenia or thrombocytopenia. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated by using either random effects or fixed effects models according to the heterogeneity of included studies.. A total of 5436 patients with a variety of solid tumors from 26 clinical trials were included for the meta-analysis. The overall incidences of mTOR inhibitor associated all-grade and high-grade hematologic toxicities were, respectively: anemia--38.8% and 7.5%; leucopenia--19.6% and 1.8%; neutropenia--14.9% and 5.6%; thrombocytopenia--33.1% and 3.6%. Compared to placebo/control arms, mTOR inhibitors were associated with a significantly increased risk of all-grade (RR 2.05, 95% CI: 1.52-2.77; p < 0.001) and high-grade anemia (RR 1.57, 95% CI: 1.20-2.05; p = 0.001), all-grade (RR 6.03, 95% CI: 2.76-13.14; p < 0.001) and high-grade thrombocytopenia (RR 2.73, 95% CI: 1.87-3.99; p < 0.001). Additionally, a non-significantly increased risk of all-grade leucopenia (RR 1.46, 95% CI: 0.66-3.23; p = 0.34) and neutropenia (RR 1.77, 95% CI: 0.80-3.93; p = 0.16) was observed in the mTOR inhibitor group, while the risk of high-grade leucopenia (RR 0.53, 95% CI: 0.31-0.90, p = 0.019) and neutropenia (RR 0.96, 95% CI: 0.62-1.51; p = 0.87) did not increase. Similar results were also observed in sub-group analysis according to mTOR inhibitor based regimens.. The use of mTOR inhibitors is associated with a significant increase in the risk of developing all-grade and high-grade anemia and thrombocytopenia compared with placebo/control arms.

Topics: Anemia; Antineoplastic Agents; Everolimus; Humans; Immunosuppressive Agents; Incidence; Neoplasms; Neutropenia; Protein Kinase Inhibitors; Risk; Sirolimus; Thrombocytopenia; TOR Serine-Threonine Kinases

Pharmacologic inhibition of the mechanistic target of rapamycin (mTOR) represents a stress test for tumor cells and T cells. Mechanisms exist that allow cells to survive this stress, including suboptimal target block, alternative signaling pathways, and autophagy. Rapamycin-resistant effector T (T-Rapa) cells have an altered phenotype that associates with increased function. Ex vivo rapamycin, when used in combination with polarizing cytokines and antigen-presenting-cell free costimulation, is a flexible therapeutic approach as polarization to T-helper 1 (Th1)- or Th2-type effectors is possible. Murine T-Rapa cells skewed toward a Th2-type prevented graft rejection and graft-versus-host disease (GVHD) more potently than control Th2 cells and effectively balanced GVHD and graft-versus-tumor (GVT) effects. A phase II clinical trial using low-intensity allogeneic hematopoietic cell transplantation demonstrated that interleukin-4 polarized human T-Rapa cells had a mixed Th2/Th1 phenotype; T-Rapa cell recipients had a balanced Th2/Th1 cytokine profile, conversion of mixed chimerism toward full donor chimerism, and a potentially favorable balance between GVHD and GVT effects. In addition, a phase I clinical trial evaluating autologous T-Rapa cells skewed toward a Th1- and Tc1-type is underway. Use of ex vivo rapamycin to modulate effector T-cell function represents a promising new approach to transplantation therapy.

Topics: Animals; Cell- and Tissue-Based Therapy; Clinical Trials as Topic; Drug Resistance; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Neoplasms; Sirolimus; T-Lymphocyte Subsets; Th1 Cells; Th2 Cells; TOR Serine-Threonine Kinases; Transplantation, Homologous

In patients with solid tumours, daily everolimus dosing demonstrated dose proportionality and linear pharmacokinetics. A meta-analysis was conducted to characterise the relationship between everolimus Cmin and efficacy and safety and the effect of CYP3A4 and P-glycoprotein (PgP) substrate/inhibitor/inducer coadministration on everolimus trough concentration (Cmin).. Individual patient data from five phase 2/3 studies, in which steady state, predose pharmacokinetic samples were taken from patients with solid tumours administered everolimus 10mg/day, were pooled.. Efficacy and safety were evaluable for 945 and 938 patients, respectively. A 2-fold increase in everolimus Cmin increased the likelihood of tumour size reduction (odds ratio 1.40, 95% confidence interval (CI) 1.23-1.60), was associated with a trend for reduced risk of progression-free survival events (risk ratio [RR] 0.90, 95% CI 0.69-1.18) and increased the risk of grade ⩾3 pulmonary (RR 1.93, 95% CI 1.12-3.34), stomatitis (RR 1.49, 95% CI 1.05-2.10) and metabolic (RR 1.30, 95% CI 1.02-1.65) events. Coadministering everolimus with strong CYP3A4 and PgP inhibitors increased everolimus Cmin by 10% and 20%, respectively; coadministration with CYP3A4 inducers reduced Cmin by 7%.. A 2-fold increase in everolimus Cmin was associated with improved tumour size reduction and increased risk of high-grade pulmonary, metabolic and stomatitis events.. Novartis Pharmaceuticals Corporation.

Topics: Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Clinical Trials as Topic; Cytochrome P-450 CYP3A; Cytochrome P-450 CYP3A Inhibitors; Disease-Free Survival; Everolimus; Humans; Neoplasms; Randomized Controlled Trials as Topic; Sirolimus

The mammalian target of rapamycin (mTOR) signaling pathway is a master regulator of cell growth and metabolism. Deregulation of the mTOR pathway has been implicated in a number of human diseases such as cancer, diabetes, obesity, neurological diseases, and genetic disorders. Rapamycin, a specific inhibitor of mTOR, has been shown to be useful in the treatment of certain diseases. Here we discuss its mechanism of action and highlight recent findings regarding the effects and limitations of rapamycin monotherapy and the potential utility of combination therapy with rapamycin.

Topics: Aging; Drug Therapy, Combination; Humans; Longevity; Lung Diseases; Metabolic Diseases; Neoplasms; Nervous System Diseases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Everolimus (RAD001, Afinitor®) is an oral protein kinase inhibitor of the mammalian target of rapamycin (mTOR) serine/threonine kinase signal transduction pathway. The mTOR pathway regulates cell growth, proliferation, and survival and is frequently deregulated in cancer. Everolimus has been approved by the FDA and the EMA for the treatment of advanced renal cell carcinoma (RCC), subependymal giant cell astrocytoma (SEGA) associated with tuberous sclerosis (TSC), pancreatic neuroendocrine tumors (PNET), in combination with exemestane in advanced hormone-receptor (HR)-positive, HER2-negative breast cancer. Everolimus shows promising clinical activity in additional indications. Multiple phase 2 and phase 3 trials of everolimus alone or in combination are ongoing and will help to further elucidate the role of mTOR in oncology. For a review on everolimus as immunosuppressant, please consult other sources.

Topics: Animals; Antineoplastic Agents; Everolimus; Humans; Neoplasms; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Temsirolimus, an ester of sirolimus (rapamycin), selectively inhibits the kinase mammalian target of rapamycin (mTOR) and consequently blocks the translation of cell cycle regulatory proteins and prevents overexpression of angiogenic growth factors. It has been found to have antitumour activity in patients with relapsed or refractory mantle cell lymphoma (MCL). In addition, patients with advanced renal cell carcinoma (RCC) and a poor prognosis who received a once-weekly intravenous (IV) infusion of temsirolimus 25 mg experienced significant survival benefits compared with patients receiving standard interferon-α (IFN-α) therapy in a large phase III clinical study. In this study, median overall survival was 10.9 versus 7.3 months and objective response rates were 8.6% in temsirolimus recipients versus 4.8% IFN-α recipient group. Temsirolimus monotherapy recipients experienced significantly fewer grade 3 or 4 adverse events and had fewer withdrawals for adverse events than patients receiving IFN-α. The role of temsirolimus in sequential and combination therapy is yet to be found.

Topics: Animals; Antineoplastic Agents; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

The overall incidence and odds of fatal adverse events (FAEs) after exposure to everolimus are not well defined. We performed a comprehensive meta-analysis of published randomized controlled trials (RCTs) to determine the role of everolimus in treatment-related mortality in patients with cancer.. PubMed databases and abstracts from the proceedings of the American Society of Clinical Oncology and the San Antonio Breast Cancer Symposium were searched for RCTs of everolimus either alone or in combination with another agent compared with the control arm without everolimus and that reported deaths from an adverse event from January 1966 to July 2013. The primary objective was to determine the difference of FAEs between everolimus-treated patients and control group patients.. In total, 2,997 patients with multiple solid tumors from nine RCTs were included. The overall incidence of FAEs in cancer patients treated with everolimus was 0.7% (95% CI 0.3%-1.1%) compared with 0.4% (95% CI 0.0%-0.7%) in cancer patients who did not receive everolimus. The odds ratio of FAEs was greater in everolimus-treated patients (Peto odds ratio = 3.80, 95% CI 1.59-9.07, p = .003). In subgroup analyses, no significant difference was found in the incidence or odds of FAEs by everolimus administration (alone or in combination) or tumor type (breast cancer vs. nonbreast cancer; p = .63).. In patients with cancer, everolimus is associated with a small but significant increase in the odds of a treatment-related fatal events.

Topics: Drug-Related Side Effects and Adverse Reactions; Everolimus; Humans; Neoplasms; Patients; Protein Kinase Inhibitors; Randomized Controlled Trials as Topic; Sirolimus

We performed a systematic review and meta-analysis of mucocutaneous toxicities associated with the use of everolimus in solid tumors.. Eligible studies included randomized Phase II and III trials of patients with solid tumors on everolimus; describing events of stomatitis, skin rash, pruritus and mouth ulceration.. Our search strategy yielded 380 potentially relevant citations on everolimus from Pubmed/Medline, CENTRAL Cochrane registry and American Society of Clinical Oncology meeting library. After exclusion of ineligible studies, a total of 10 clinical trials were considered eligible for the meta-analysis, including eight Phase III trials and two Phase II trials. The relative risk of all-grade stomatitis, skin rash, pruritus and mouth ulceration were 3.86(95% CI: 2.23-6.68; p < 0.001); 3.49(95% CI: 2.39-5.08; p < 0.0001); 2.85(95% CI: 2.04-3.97; p = 0.0001); 3.31 (95% CI: 1.46-7.50; p = 0.004); respectively. Exploratory subgroup analysis showed no effect of tumor types or treatment regimen on the relative risk of the relevant adverse events.. Our meta-analysis has demonstrated that everolimus is associated with a significantly increased risk of all-grade stomatitis, skin rash, and pruritus and mouth ulceration. Clinicians should be aware of these risks and perform early clinical assessment and intervene accordingly.

Topics: Everolimus; Humans; Mucous Membrane; Neoplasms; Randomized Controlled Trials as Topic; Sirolimus; Skin

Rapamycin, an inhibitor of mechanistic target of rapamycin (mTOR), has the strongest experimental support to date as a potential anti-aging therapeutic in mammals. Unlike many other compounds that have been claimed to influence longevity, rapamycin has been repeatedly tested in long-lived, genetically heterogeneous mice, in which it extends both mean and maximum life spans. However, the mechanism that accounts for these effects is far from clear, and a growing list of side effects make it doubtful that rapamycin would ultimately be beneficial in humans. This Review discusses the prospects for developing newer, safer anti-aging therapies based on analogs of rapamycin (termed rapalogs) or other approaches targeting mTOR signaling.

Topics: Aging; Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Autophagy; Humans; Metformin; Molecular Targeted Therapy; Neoplasms; Sirolimus; Stem Cells; TOR Serine-Threonine Kinases

Rapamycin and its derivatives (rapalogs), a group of allosteric inhibitors of mammalian target of rapamycin (mTOR), have been actively tested in a variety of cancer clinical trials, and some have been approved by the Food and Drug Administration for the treatment of certain types of cancers. However, the single agent activity of these compounds in many tumor types remains modest. The mTOR axis is regulated by multiple upstream signaling pathways. Because the genes (e.g., PIK3CA, KRAS, PTEN, and LKB1) that encode key components in these signaling pathways are frequently mutated in human cancers, a subset of cancer types may be addicted to a given mutation, leading to hyperactivation of the mTOR axis. Thus, efforts have been made to demonstrate the potential impact of genetic alterations on rapalog-based or mTOR-targeted cancer therapy. This review will primarily summarize research advances in this direction.

Topics: AMP-Activated Protein Kinase Kinases; Antibiotics, Antineoplastic; Cell Line, Tumor; Class I Phosphatidylinositol 3-Kinases; Humans; Mutation; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins p21(ras); PTEN Phosphohydrolase; ras Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Cancer and aging appear to be inexorably linked, yet approaches to ameliorate them in concert are lacking. Although not (easily) feasible in humans, years of preclinical research show that diet and growth factor restriction each successfully address cancer and aging together. Chronic treatment of genetically heterogeneous mice with an enteric formulation of rapamycin (eRapa) extended maximum lifespan of both genders when started in mid or late life. In part, cancer amelioration in treated mice suggested that long-term eRapa, like diet restriction, could be a pharmacological approach feasible for use in the clinic. We review the current understanding of the role of the mechanistic target of rapamycin (mTOR) in cancer and aging. We also discuss the tumor immune surveillance system, and the need for a better understanding of its responses to mTOR inhibitors. We also address the issue of the misperception that rapamycin is a potent immunosuppressant. Finally, we review the current state of mTOR inhibitors in the cancer clinic. Because of the burgeoning elderly population most at risk for cancer, there is a great need for our eRapa findings to be a proof of concept for the development of new and more comprehensive approaches to cancer prevention that are safe and also mitigate other deleterious effects of aging.

Topics: Aging; Animals; Antibiotics, Antineoplastic; Caenorhabditis elegans; Caloric Restriction; Drosophila melanogaster; Drug Evaluation, Preclinical; Humans; Immunosuppression Therapy; Intercellular Signaling Peptides and Proteins; Life Expectancy; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Neoplasms; Signal Transduction; Sirolimus; Systems Biology; Time; TOR Serine-Threonine Kinases

The phosphoinositide 3-kinase-AKT-mammalian target of rapamycin (PI3K-AKT-mTOR) pathway is a frequently hyperactivated pathway in cancer and is important for tumor cell growth and survival. The development of targeted therapies against mTOR, a vital substrate along this pathway, led to the approval of allosteric inhibitors, including everolimus and temsirolimus, for the treatment of breast, renal, and pancreatic cancers. However, the suboptimal duration of response in unselected patients remains an unresolved issue. Numerous novel therapies against critical nodes of this pathway are therefore being actively investigated in the clinic in multiple tumor types. In this review, we focus on the progress of these agents in clinical development along with their biological rationale, the need of predictive biomarkers and various combination strategies, which will be useful in counteracting the mechanisms of resistance to this class of drugs.

Topics: Antineoplastic Agents; Drug Resistance, Neoplasm; Humans; Molecular Targeted Therapy; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-ret; PTEN Phosphohydrolase; Sirolimus; TOR Serine-Threonine Kinases

Everolimus is a potent, oral inhibitor of the mammalian target of rapamycin (mTOR) that has been investigated in multiple clinical development programs since 1996. A unique collaboration between academic and pharmaceutical experts fostered research that progressed rapidly, with simultaneous indication findings across numerous tumor types. Initially developed for the prophylaxis of organ transplant rejection, everolimus has demonstrated efficacy and safety for the treatment of patients with various types of cancer (renal cell carcinoma, neuroendocrine tumors of pancreatic origin, and breast cancer) and for adult and pediatric patients with tuberous sclerosis complex. The FDA approval of everolimus for these diseases has addressed several unmet medical needs and is widely accepted by the medical community where treatment options may be limited. An extensive clinical development program is ongoing to establish the role of everolimus as monotherapy, or in combination with other agents, in the treatment of a broad spectrum of malignancies.

Topics: Administration, Oral; Animals; Antineoplastic Agents; Clinical Trials as Topic; Everolimus; Humans; Immunosuppressive Agents; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis

The mammalian target of rapamycin (mTOR) is a serine/threonine kinase, which is the key component of two distinct signaling complexes in cells; these complexes are the mTOR complex 1 (mTORC1) and the mTOR complex 2 (mTORC2). Given the importance of these complexes in cellular growth, survival, motility, proliferation, protein synthesis and transcription, it is not surprising that they are impacted in multiple types of cancer. Studies on a number of ATP-competitive mTOR inhibitors have suggested that these inhibitors have a therapeutic superiority to rapalogs (rapamycin analogs) in a number of cancers.. This review provides insight into the binding of mTOR inhibitors with the ATP-binding site, for the benefit of future mTOR inhibitor design and discovery. The authors, furthermore, deduce that a hypothetical binding mode is from docking studies, co-crystal structures and the structure-activity relationships (SARs). The authors also highlight the preclinical and clinical development of hit/lead compounds, and the selectivity for representative mTOR inhibitors.. The structural analysis of mTOR is hampered by its large size and complexity. Further exploration of mTOR inhibitors may therefore require the combination of structure-based drug design (SBDD, based on the mTOR homology models), fragment-based drug design (FBDD) and analog synthesis. Recent studies suggested that the global inhibition of PI3Ks may be harmful to organisms. Therefore, the future discovery of dual mTOR/PI3K inhibitors needs to ensure that inhibitors are both efficacious and have reduced adverse effects.

Topics: Adenosine Triphosphate; Animals; Antineoplastic Agents; Drug Discovery; Humans; Neoplasms; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases

Deregulation of the phosphatidylinositide 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signaling pathway occurs frequently in a wide range of human cancers and is a major driving force in tumorigenesis. Thus, small molecules targeting this pathway are under active development as anticancer therapeutics. Although small-molecule inhibitors of the PI3K-mTOR pathway have shown promising clinical efficacy against human cancers, the emergence of drug resistance may limit their success in the clinic. To date, several resistance mechanisms, including both PI3K-dependent and -independent mechanisms, have been described. Here, we summarize the current understanding of resistance mechanisms to PI3K-mTOR inhibitors and discuss potential strategies for overcoming resistance for potential clinical application.

Topics: Antineoplastic Agents; Drug Resistance, Neoplasm; Genes, myc; Humans; Molecular Targeted Therapy; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proto-Oncogene Proteins c-myc; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Everolimus is an orally administered inhibitor of the mammalian target of rapamycin (mTOR), an intracellular protein kinase downstream of the phosphatidylinositol 3-kinase/AKT pathway involved in key components of tumorigenesis, including cell growth, proliferation, and angiogenesis. In the advanced cancer setting, based on favorable results from phase III trials, everolimus is indicated for the treatment of advanced renal cell carcinoma, advanced neuroendocrine tumors of pancreatic origin, and advanced hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer. Additional oncology indications for everolimus include renal angiomyolipoma with tuberous sclerosis complex and subependymal giant-cell astrocytoma. Although it is generally well tolerated, with most adverse events of mild to moderate severity and manageable, everolimus exhibits a distinct adverse event profile that warrants guidance for proper diagnostic and medical management. This guidance is particularly important given the potential for widespread long-term use of everolimus. This review will focus on the most relevant toxicities associated with mTOR inhibitors and on their management. Practical treatment recommendations are presented for stomatitis, noninfectious pneumonitis, rash, selected metabolic abnormalities, and infections. Provided these events are rapidly identified and treated, the vast majority should resolve with minimal effect on treatment outcomes and patients' quality of life.

Topics: Antineoplastic Agents; Everolimus; Humans; Infection Control; Infections; Inflammation; Neoplasms; Sirolimus

The mechanistic Target of Rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase which is a member of the PI3K related kinase (PIKK) family. mTOR emerged as a central node in cellular metabolism, cell growth, and differentiation, as well as cancer metabolism. mTOR senses the nutrients, energy, insulin, growth factors, and environmental cues and transmits signals to downstream targets to effectuate the cellular and metabolic response. Recently, mTOR was also implicated in the regulation of both the innate and adaptive immune responses. This paper will summarize the current knowledge of mTOR, as related to the immune microenvironment and immune responses.

Topics: Adaptive Immunity; Carbohydrate Metabolism; Cell Differentiation; Cell Proliferation; Humans; Immunity, Innate; Immunosuppressive Agents; Lipid Metabolism; Neoplasms; Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Two novel mammalian targets of rapamycin (mTOR) inhibitors everolimus and temsirolimus are now approved by regulatory agencies and have been widely investigated among various types of solid tumors, but the risk of fatal adverse events (FAEs) with these drugs is not well defined.. We searched PubMed, EMBASE, and Cochrane library databases for relevant trials. Eligible studies included prospective phase II and III trials evaluating everolimus and temsirolimus in patients with all malignancies and data on FAEs were available. Statistical analyses were conducted to calculate the summary incidence, RRs and 95% confidence intervals (CIs) by using either random effects or fixed effect models according to the heterogeneity of the included studies.. A total of 3322 patients with various advanced solid tumors from 12 trials were included. The overall incidence of mTOR inhibitors associated FAEs was 1.8% (95%CI: 1.3-2.5%), and the incidences of everolimus related FAEs were comparable to that of temsirolimus (1.7% versus 1.8%). Compared with the controls, the use of mTOR inhibitors was associated with an increased risk of FAEs, with a RR of 3.24 (95%CI: 1.21-8.67, p = 0.019). On subgroup analysis, a non-statistically significant increase in the risk of FAEs was found according to different mTOR inhibitors, tumor types or controlled therapy. No evidence of publication bias was observed.. With the present evidence, the use of mTOR inhibitors seems to increase the risk of FAEs in patients with advanced solid tumors. More high quality trials are still needed to investigate this association.

Topics: Antineoplastic Agents; Cause of Death; Everolimus; Humans; Incidence; Neoplasms; Protein Kinase Inhibitors; Risk; Sirolimus; TOR Serine-Threonine Kinases

We performed a systematic review and meta-analysis of hematologic toxicities associated with everolimus, an oral mammalian target of rapamycin (mTOR) inhibitor. Eligible studies included phase II and III trials of patients with solid tumors on 10mg of everolimus daily describing events of neutropenia, thrombocytopenia, anemia or lymphopenia. The incidence of everolimus-associated all-grade and high-grade (Grade 3-4) hematologic toxicities were, respectively: neutropenia: 21.7% and 3.6%; thrombocytopenia: 36.0% and 4.7%; anemia: 61.2% and 8.4% and lymphopenia: 40.9% and 14.9%. Everolimus was associated with an increased risk of all-grade neutropenia (RR=2.24, [95% CI 1.51-3.32]), all-grade (RR=9.19, [95% CI 4.51-18.70]) and high-grade (RR=7.46, [95% CI 2.58-21.61]) thrombocytopenia, all-grade (RR=1.58, [95% CI 1.25-1.99]) and high-grade (RR=3.92, [95% CI 1.46-10.52]) anemia and all-grade (RR=1.72, [95% CI 1.50-1.97]) and high-grade (RR=2.70, [95% CI 1.86-3.93]) lymphopenia.

Topics: Antineoplastic Agents; Everolimus; Hematologic Diseases; Humans; Incidence; Neoplasms; Odds Ratio; Publication Bias; Risk; Sirolimus

The PI3K/AKT/mammalian target of rapamycin (mTOR) pathway plays a critical role in controlling cellular metabolism, proliferation and cell cycle regulation. Constitutive activation of this pathway has been demonstrated in many tumor types. Targeting the PI3K/AKT/mTOR pathway is of increasing therapeutic interest.. Ridaforolimus belongs to a class of agents known as the rapalogs, first-generation mTOR inhibitors, which inhibit mTORC1, a part of the mTOR complex. Both oral and intravenous formulations of this agent have been tested in Phase II clinical trials for the treatment of solid tumors and hematologic malignancies. Promising results have been seen in endometrial cancer and soft tissue and bone sarcomas.. This article summarizes the current clinical and biological data on the use of ridaforolimus emerging from these Phase II studies, and provides potential advantages and drawbacks of the mTOR inhibitors in the current clinical practice.

Topics: Antineoplastic Agents; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Autophagy, an evolutionarily conserved lysosomal degradation process, has drawn an increasing amount of attention in recent years for its role in a variety of human diseases, such as cancer. Notably, autophagy plays an important role in regulating several survival and death signaling pathways that determine cell fate in cancer. To date, substantial evidence has demonstrated that some key autophagic mediators, such as autophagy-related genes (ATGs), PI3K, mTOR, p53, and Beclin-1, may play crucial roles in modulating autophagic activity in cancer initiation and progression. Because autophagy-modulating agents such as rapamycin and chloroquine have already been used clinically to treat cancer, it is conceivable that targeting autophagic pathways may provide a new opportunity for discovery and development of more novel cancer therapeutics. With a deeper understanding of the regulatory mechanisms governing autophagy, we will have a better opportunity to facilitate the exploitation of autophagy as a target for therapeutic intervention in cancer. This review discusses the current status of targeting autophagic pathways as a potential cancer therapy.

Topics: Antibiotics, Antineoplastic; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Chloroquine; Drug Discovery; Humans; Membrane Proteins; Molecular Targeted Therapy; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Suppressor Protein p53

Atypical serine-threonine kinase, mTOR (mechanistic target of Rapamycin; originally coined "mammalian TOR"), exists in two distinct multi-protein complexes termed mTOR complex 1 (mTORC1) and 2 (mTORC2), that senses and integrates a variety of environmental signals to control organism growth and homeostasis via non-overlapping signaling pathways. mTOR belongs to the phosphoinositide 3-kinase (PI3-K)-related kinase family, and an aberrant activation of mTORC1 is a potential contributing factor in uncontrolled cell growth, proliferation, and survival of tumor cells via specific effects on cap-dependent translation initiation, as well as in a more sustained manner via advancing ribosome biogenesis. It is thereby shown to be deregulated in numerous pathological conditions including cancer, obesity, type 2 diabetes, and neurodegeneration. Notably, mTOR itself, or through its substrates, regulates stem cell differentiation and maintenance of plueropotency. mTORC2 has been linked to cytoskeletal reorganization and cell survival through Akt, and is crucial to many divergent physiological functions, which may include stem cell regulation.

Topics: Cell Differentiation; Glioblastoma; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Multiprotein Complexes; Neoplasms; Proto-Oncogene Proteins c-akt; Sirolimus; Stem Cells; TOR Serine-Threonine Kinases

The serine/threonine kinase LKB1 is a master kinase involved in cellular responses such as energy metabolism, cell polarity and cell growth. LKB1 regulates these crucial cellular responses mainly via AMPK/mTOR signaling. Germ-line mutations in LKB1 are associated with the predisposition of the Peutz-Jeghers syndrome in which patients develop gastrointestinal hamartomas and have an enormously increased risk for developing gastrointestinal, breast and gynecological cancers. In addition, somatic inactivation of LKB1 has been associated with sporadic cancers such as lung cancer. The exact mechanisms of LKB1-mediated tumor suppression remain so far unidentified; however, the inability to activate AMPK and the resulting mTOR hyperactivation has been detected in PJS-associated lesions. Therefore, targeting LKB1 in cancer is now mainly focusing on the activation of AMPK and inactivation of mTOR. Preclinical in vitro and in vivo studies show encouraging results regarding these approaches, which have even progressed to the initiation of a few clinical trials. In this review, we describe the functions, regulation and downstream signaling of LKB1, and its role in hereditary and sporadic cancers. In addition, we provide an overview of several AMPK activators, mTOR inhibitors and additional mechanisms to target LKB1 signaling, and describe the effect of these compounds on cancer cells. Overall, we will explain the current strategies attempting to find a way of treating LKB1-associated cancer.

Topics: AMP-Activated Protein Kinase Kinases; Animals; Cell Polarity; Humans; Metformin; Neoplasms; Protein Serine-Threonine Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The target of rapamycin (TOR) is a highly conserved serine/threonine kinase that is part of two structurally and functionally distinct complexes, TORC1 and TORC2. In multicellular organisms, TOR regulates cell growth and metabolism in response to nutrients, growth factors and cellular energy. Deregulation of TOR signaling alters whole body metabolism and causes age-related disease. This review describes the most recent advances in TOR signaling with a particular focus on mammalian TOR (mTOR) in metabolic tissues vis-a-vis aging, obesity, type 2 diabetes, and cancer.

Topics: Aging; Animals; Cell Proliferation; Diabetes Mellitus, Type 2; Gene Deletion; Gene Expression Regulation; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Multiprotein Complexes; Neoplasms; Obesity; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The phosphatidylinositol 3-kinase (PI3K) pathway has an important role in cell metabolism, growth, migration, survival and angiogenesis. Drug development aimed at targetable genetic aberrations in the PI3K/AKT/mTOR pathway has been fomented by observations that alterations in this pathway induce tumour formation and that inappropriate PI3K signalling is a frequent occurrence in human cancer. Many of the agents developed have been evaluated in early stage clinical trials. This Review focuses on early clinical and translational data related to inhibitors of the PI3K/AKT/mTOR pathway, as these data will likely guide the further clinical development of such agents. We review data from those trials, delineating the safety profile of the agents--whether observed sequelae could be mechanism-based or off-target effects--and drug efficacy. We describe predictive biomarkers explored in clinical trials and preclinical mechanisms of resistance. We also discuss key unresolved translational questions related to the clinical development of inhibitors of the PI3K/AKT/mTOR pathway and propose designs for biomarker-driven trials to address those issues.

Topics: Animals; Antineoplastic Agents; Biomarkers; Clinical Trials as Topic; Humans; Isoenzymes; Mice; Mice, Transgenic; Molecular Targeted Therapy; Neoplasm Proteins; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase Inhibitors; Protein Processing, Post-Translational; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; Substrate Specificity; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR), a serine/threonine protein kinase, acts as a "master switch" for cellular anabolic and catabolic processes, regulating the rate of cell growth and proliferation. Dysregulation of the mTOR signaling pathway occurs frequently in a variety of human tumors, and thus, mTOR has emerged as an important target for the design of anticancer agents. mTOR is found in two distinct multiprotein complexes within cells, mTORC1 and mTORC2. These two complexes consist of unique mTOR-interacting proteins and are regulated by different mechanisms. Enormous advances have been made in the development of drugs known as mTOR inhibitors. Rapamycin, the first defined inhibitor of mTOR, showed effectiveness as an anticancer agent in various preclinical models. Rapamycin analogues (rapalogs) with better pharmacologic properties have been developed. However, the clinical success of rapalogs has been limited to a few types of cancer. The discovery that mTORC2 directly phosphorylates Akt, an important survival kinase, adds new insight into the role of mTORC2 in cancer. This novel finding prompted efforts to develop the second generation of mTOR inhibitors that are able to target both mTORC1 and mTORC2. Here, we review the recent advances in the mTOR field and focus specifically on the current development of the second generation of mTOR inhibitors as anticancer agents.

Topics: Antineoplastic Agents; Cell Proliferation; Furans; Humans; Imidazoles; Indoles; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Morpholines; Multiprotein Complexes; Naphthyridines; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Purines; Pyridines; Pyrimidines; Quinolines; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is a protein kinase involved in the phosphatidylinositol 3-Kinase (PI3K)/AKT signalling pathway with a central role in the control of cell growth, survival and angiogenesis. Multiple and frequent dysregulations of this pathway in human tumors make it a central target in the development of new anticancer treatments.. To review the most significant data on mTOR pathway, role of mTOR inhibitors in cancer treatment, preclinical and clinical data of the three first generation mTOR inhibitors (temsirolimus, everolimus and deferolimus), rationales, preclinical and clinical data of second generation mTOR inhibitors.. Review of published literature on mTOR and related pathways, rapalogs and novel mTOR inhibitors.. Temsirolimus and everolimus have been approved for the treatment of metastatic Renal Cell Carcinoma (RCC), temsirolimus also for Mantle Cell Lymphoma (MCL) and everolimus will be approved for pancreatic neuroendocrine tumors; all three rapalogs are currently evaluated in phase III studies in several tumors. Only limited published data are available on new mTOR inhibitors; however, in vitro and in vivo in preclinical studies they have shown a significant antiproliferative activity against a broad panel of tumors and a favourable safety profile, with disease stabilization or even tumor regression, either as single agent or in combination.

Topics: Everolimus; Humans; Neoplasms; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Although prognosis of children with solid tumors is steadily improving, long-term survival is not achievable in all patients, especially in patients with recurrent or refractory disease. Despite the increasing number of targeted therapeutics (TT), only very few TT have been introduced into clinical protocols. Accordingly, clinical experience concerning the efficacy and safety of these drugs is limited. This may possibly discourage oncologists from administering TT to children.We performed a comprehensive review of the literature to identify TT that may be considered for treatment of children and young adults with solid tumors. Moreover, we interviewed an expert panel of the Society for Pediatric Oncology and Hematology (GPOH) using questionnaires in a modified Delphi process in order to describe the experts' experiences in the use of these TT.Among 30 TT identified to be possibly useful in children and young adults, imatinib, bevacizumab and rapamycin were most widely used. These drugs were reported as having mostly little to no severe adverse events and seem to induce at least partial responses in a subset of patients. In addition, our study confirms and expands the present knowledge about adverse events and the potential efficacy of 5 other commonly used TT in this population.This information may be useful for oncologists when administering these TT to children and young adults with solid tumors. Controlled clinical trials are urgently needed to test their safety and efficacy.

Topics: Adolescent; Antibodies, Monoclonal, Humanized; Benzamides; Bevacizumab; Child; Delphi Technique; Humans; Imatinib Mesylate; Molecular Targeted Therapy; Neoplasms; Piperazines; Pyrimidines; Sirolimus; Young Adult

Radiotherapy (RT) allows for tumor control through the cytotoxic action of ionizing radiation (IR). Although modern technologies permit precise IR delivery to the tumor mass while minimizing exposure of surrounding healthy tissues, the efficacy of RT remains limited by the intrinsic or acquired radioresistance of many tumors. There is thus an ongoing search for agents that augment the sensitivity of tumor cells to IR cytotoxicity, with recent interest in targeting components of signaling pathways involved in tumor growth and radioresistance. Here, we review the evidence suggesting that disabling one of these components, the mechanistic target of rapamycin (mTOR) kinase, may enhance RT efficacy. This molecule constitutes the catalytic subunit of the mTORC1 and mTORC2 protein complexes, which regulate cell growth and other processes implicated in tumorigenesis. Much work has focused on mTORC1 because it is selectively blocked by the microbial product rapamycin and its analogs (collectively designated rapamycins) that are approved for cancer treatment, and is frequently hyperactivated in malignant cells. In several, but not all human cancer cell lines, rapamycins increased IR cytotoxicity in vitro, apparently through multiple mechanisms, including the promotion of autophagic cell death. Rapamycins also potentiated fractionated RT in tumor xenograft models, in part by suppressing tumor angiogenesis. Synthetic kinase inhibitors that simultaneously target PI3K and both mTOR complexes also enhanced RT in vitro and in vivo, but with greater efficiency than rapamycins. These encouraging data have led to early clinical trials of rapamycins and catalytic mTOR inhibitors combined with RT in various cancers.

Topics: Animals; Autophagy; Cell Line, Tumor; DNA Repair; Humans; Mice; Neoplasms; Phosphatidylinositol 3-Kinases; Radiation-Sensitizing Agents; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

mTOR inhibitors are currently used in the treatment of solid malignancies. Since their approval, several cases of pulmonary toxicity (PT) have been described. This analysis aims to report the incidence and the risk of PT in published randomized controlled trials.. PubMed and Scopus were reviewed for phase II-III randomized controlled trials with temsirolimus and everolimus. The characteristic of each study and incidence of all- and high-grades PT were collected.. A total of 2233 patients were available for meta-analysis: 989 had breast cancer, 833 had neuroendocrine tumor and 411 had metastatic renal cell carcinoma. In patients taking mTOR inhibitors, the incidence of all- and high-grades PT was 10.4% and 2.4%, respectively. Compared to controls, the relative risk for all- and high-grades PT was 31- and 8.8-folds, respectively. No significant heterogeneity was observed between the studies. Not any relationship was found between the incidence of lung metastases, treatment exposure and the incidence of PT.. The high grade PT is a rare event and 10% of patients may experience mild grade toxicity with a worsening of quality of life and interruption of therapy in some cases. We recommend monitoring of PT in patients treated with mTOR inhibitors.

Topics: Antineoplastic Agents; Breast Neoplasms; Carcinoma, Renal Cell; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Everolimus; Humans; Incidence; Kidney Neoplasms; Lung; Neoplasms; Neuroendocrine Tumors; Pneumonia; Randomized Controlled Trials as Topic; Respiratory Function Tests; Risk; Sirolimus; TOR Serine-Threonine Kinases

Therapeutic drug monitoring (TDM) provides valuable guidance for dose adjustment of antibiotics, immunosuppressives, antiepileptics, and other drugs, but its use for traditional anticancer therapies has been limited. Perhaps the most important obstacle is the impractical requirement of multiple blood samples to adequately define systemic exposure of drugs that have a short elimination half-life and are given by intermittent intravenous injections. However, the newer targeted anticancer therapies have different pharmacokinetic (PK) and dosing characteristics compared with traditional cytotoxic drugs, making it possible to estimate the steady-state drug exposure with a single trough-level measurement. Recent evidence indicates that certain PK parameters, including trough levels, are correlated with clinical outcomes for many of these agents, including imatinib, sunitinib, rituximab, and cetuximab. Although the current evidence is insufficient to mandate TDM in routine practice, a concerted investigation should be encouraged to determine whether the steady-state trough measurements of targeted agents will have a practical place in the clinical care of patients with cancer.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal, Murine-Derived; Antineoplastic Agents; Area Under Curve; Benzamides; Benzenesulfonates; Cetuximab; Dasatinib; Drug Monitoring; Everolimus; Evidence-Based Medicine; Half-Life; Humans; Imatinib Mesylate; Indoles; Injections, Intravenous; Molecular Targeted Therapy; Neoplasms; Niacinamide; Phenylurea Compounds; Piperazines; Pyridines; Pyrimidines; Pyrroles; Rituximab; Sirolimus; Sorafenib; Sunitinib; Thiazoles

Common cancer is an age-related disease. Slow aging is associated with reduced and delayed carcinogenesis. Calorie restriction (CR), the most studied anti-aging intervention, prevents cancer by slowing down the aging process. Evidence is emerging that CR decelerates aging by deactivating MTOR (Target of Rapamycin). Rapamycin and other rapalogs suppress cellular senescence, slow down aging and postpone age-related diseases including cancer. At the same time, rapalogs are approved for certain cancer treatments. Can cancer prevention be explained by direct targeting of cancer cells? Or does rapamycin prevent cancer indirectly through slowing down the aging process? Increasing evidence points to the latter scenario.

Topics: Aging; Caloric Restriction; Cellular Senescence; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is a central component within a complex intracellular signaling network that regulates various processes including cell growth, proliferation, metabolism, and angiogenesis. A hyperactive PI3k/Akt/mTOR signaling pathway is found in many human cancers and alterations in this pathway is associated with the development and progression of cancer. Drugs that target and inhibit mTOR activity are therefore expected to provide therapeutic value in a number of cancer types. Several classes of mTOR-targeted therapeutics are currently being evaluated in cancer clinical trials, including the rapamycins, dual PI3K-mTOR inhibitors, and ATP-competitive mTORC1/2 inhibitors. This review summarizes important findings from recently completed trials of mTOR inhibitors and also discusses preliminary data from ongoing trials.

Topics: Antibiotics, Antineoplastic; Clinical Trials as Topic; Humans; Neoplasms; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

The reductions in mortality and morbidity being achieved among cancer patients with current therapies represent a major achievement. However, given their mechanisms of action, many anti-cancer agents may have significant potential for cardiovascular side effects, including the induction of heart failure. The magnitude of this problem remains unclear and is not readily apparent from current clinical trials of emerging targeted agents, which generally under-represent older patients and those with significant co-morbidities. The risk of adverse events may also increase when novel agents, which frequently modulate survival pathways, are used in combination with each other or with other conventional cytotoxic chemotherapeutics. The extent to which survival and growth pathways in the tumour cell (which we seek to inhibit) coincide with those in cardiovascular cells (which we seek to preserve) is an open question but one that will become ever more important with the development of new cancer therapies that target intracellular signalling pathways. It remains unclear whether potential cardiovascular problems can be predicted from analyses of such basic signalling mechanisms and what pre-clinical evaluation should be undertaken. The screening of patients, optimization of therapeutic schemes, monitoring of cardiovascular function during treatment, and the management of cardiovascular side effects are likely to become increasingly important in cancer patients. This paper summarizes the deliberations of a cross-disciplinary workshop organized by the Heart Failure Association of the European Society of Cardiology (held in Brussels in May 2009), which brought together clinicians working in cardiology and oncology and those involved in basic, translational, and pharmaceutical science.

Topics: Anthracyclines; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Cardiology; Cardiotoxins; Cardiovascular System; Education; ErbB Receptors; Europe; Heart Failure; Humans; Neoplasms; Practice Guidelines as Topic; Risk Factors; Sirolimus; Trastuzumab

The liver kinase B1 (LKB1)/adenosine mono-phosphate-activated protein kinase (AMPK)/tuberous sclerosis complex (TSC)/mammalian target of rapamycin (mTOR) complex (mTORC1) cassette constitutes a canonical signaling pathway that integrates information on the metabolic and nutrient status and translates this into regulation of cell growth. Alterations in this pathway are associated with a wide variety of cancers and hereditary hamartoma syndromes, diseases in which hyperactivation of mTORC1 has been described. Specific mTORC1 inhibitors have been developed for clinical use, and these drugs have been anticipated to provide efficient treatment for these diseases. In the present review, we provide an overview of the metabolic LKB1/AMPK/TSC/mTORC1 pathway, describe how its aberrant signaling associates with cancer development, and indicate the difficulties encountered when biochemical data are extrapolated to provide avenues for rational treatment of disease when targeting this signaling pathway. A careful examination of preclinical and clinical studies performed with rapamycin or derivatives thereof shows that although results are encouraging, we are only half way in the long and winding road to design rationale treatment targeted at the LKB1/AMPK/TSC/mTORC1 pathway. Inherited cancer syndromes associated with this pathway such as the Peutz-Jeghers syndrome and TSC, provide perfect models to study the relationship between genetics and disease phenotype, and to delineate the complexities that underlie translation of biochemical and genetical information to clinical management, and thus provide important clues for devising novel rational medicine for cancerous diseases in general.

Topics: AMP-Activated Protein Kinase Kinases; Antibiotics, Antineoplastic; Humans; Molecular Targeted Therapy; Neoplasms; Protein Kinases; Protein Serine-Threonine Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis

Calcineurin inhibitor drugs (CNI) are the mainstay of modern immunosuppression in renal transplantation. However, they contribute significantly to the chronic loss of renal grafts and the high morbidity and mortality in this population due to their deleterious effects on the renal graft, cardiovascular profile and tumour pathology. Anti-mTOR drugs, sirolimus (SRL) and everolimus (EVE) are potent immunosuppressants with antiproliferative and anti-migratory capacities. These properties mean that they have a potential protective role in graft dysfunction, in renal function optimisation and the appearance of malignant tumours. Indeed, clinical trials and observational studies have demonstrated that conversion from CNI to anti-mTOR-based maintenance therapy has beneficial effects on transplant outcomes in terms of renal function, without significant increase in acute rejection rates. This review article examines the evidence of the use of anti-mTOR in the following clinical situations following renal transplantation: 1) prevention of immune dysfunction and renal function preservation in de novo renal transplantation and after early or late CNI withdrawal; 2) chronic dysfunction of the renal graft; 3) cardiovascular effects; 4) de novo post-transplant diabetes, and 5) de novo tumour pathology.

Topics: Animals; Calcineurin Inhibitors; Diabetes Mellitus, Type 2; Dyslipidemias; Everolimus; Evidence-Based Medicine; Graft Rejection; Graft vs Host Disease; Humans; Hypertrophy, Left Ventricular; Immunosuppressive Agents; Kidney; Kidney Transplantation; Models, Animal; Multicenter Studies as Topic; Neoplasms; Postoperative Complications; Randomized Controlled Trials as Topic; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of the rapamycin (mTOR) signalling pathway has a central role in the regulation of cell growth, survival and angiogenesis and the frequent dysregulation of this pathway in tumor cells makes it a crucial target in the treatment of cancer. Temsirolimus and everolimus are approved for use in metastatic renal cell carcinoma and temsirolimus is also approved for mantle cell lymphoma. All three rapalogs, temsirolimus, everolimus and deforolimus, are currently being evaluated in Phase III studies in several tumors.. This paper provides a review of the published literature on the mTOR pathway and related pathway signaling, analogs and novel mTOR inhibitors. The most recent and important data on the mTOR pathway, the role of mTOR inhibitors in cancer treatment and the current status of development of second-generation highly potent and selective mTOR inhibitors are overviewed.. The published data on new mTOR inhibitors are still limited, but the available preclinical results indicate that they have a potent antiproliferative activity against a broad panel of tumor cell lines, have a favorable safety profile, can obtain disease stabilization or even tumor regression and, in some cases, enhance the efficacy of other targeted or standard-of-care anticancer drugs when used in vivo in preclinical studies.

Topics: Animals; Antineoplastic Agents; Clinical Trials, Phase III as Topic; Humans; Neoplasms; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

It is becoming increasingly clear that dysregulation of protein synthesis contributes to a range of diseases characterized by tissue overgrowth. These include arterial stenosis, cardiac hypertrophy, hamartomas, and cancer. The central hub for the regulation of protein synthesis is the ribosome, where the key signaling pathways downstream of RAS, MYC, and phosphatidylinositol-3-kinase (PI3K) converge to confer exquisite, coordinated control of ribosome synthesis and function. Such cooperation ensures strict regulation of protein synthesis rates and cell growth. This review will focus on the role the PI3K/AKT/mammalian target of rapamycin complex 1 (mTORC1) pathway plays in regulating ribosome function during both health and disease, its interaction with the other key growth regulatory pathways activated by RAS and MYC, and the therapeutic potential for targeting this network.

Topics: Animals; Cell Proliferation; Humans; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Biosynthesis; Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-myc; ras Proteins; Ribosomes; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

AZD8055 is a small-molecule inhibitor of mTOR (mammalian target of rapamycin) kinase activity. The present review highlights molecular and phenotypic differences between AZD8055 and allosteric inhibitors of mTOR such as rapamycin. Biomarkers, some of which are applicable to clinical studies, as well as biological effects such as autophagy, growth inhibition and cell death are compared between AZD8055 and rapamycin. Potential ways to develop rational combinations with mTOR kinase inhibitors are also discussed. Overall, AZD8055 may provide a better therapeutic strategy than rapamycin and analogues.

Topics: Animals; Antineoplastic Agents; Drug Evaluation, Preclinical; Humans; Medical Oncology; Molecular Targeted Therapy; Morpholines; Neoplasms; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases

FK506-binding proteins (FKBPs) are intracellular receptors for FK506 and rapamycin, immunosuppressants that have recently been utilized as anticancer drugs. In the cytoplasm, FKBPs and these drugs modulate signal transduction pathways. However, recent reports reveal novel functions of FKBPs in the nucleus, which include regulation of transcription factors, histone chaperone activity, and modifications of chromatin structure. These activities are known to affect gene expression, DNA repair, and DNA replication. Therefore, elucidation of the nuclear functions of FKBPs will help researchers and clinicians better understand how immunosuppressants work as anticancer drugs, which might in turn lead to novel designs of cancer therapy.

Topics: Animals; Antineoplastic Agents; Chromatin; Drug Design; Humans; Immunosuppressive Agents; Neoplasms; Signal Transduction; Sirolimus; Tacrolimus; Tacrolimus Binding Proteins

Mammalian target of rapamycin (mTOR) is a PI3K-related kinase that regulates cell growth, proliferation, and survival via mTOR complex 1 (mTORC1) and mTORC2. The mTOR pathway is often aberrantly activated in cancers. While hypoxia, nutrient deprivation, and DNA damage restrain mTORC1 activity, multiple genetic events constitutively activate mTOR in cancers. Here we provide a brief overview of the signaling pathways up- and downstream of mTORC1 and -2, and discuss the insights into therapeutic anticancer targets - both those that have been tried in the clinic with limited success and those currently under clinical development - that knowledge of these pathways gives us.

Topics: Antineoplastic Agents; Clinical Trials as Topic; Female; Humans; Male; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

mTOR-inhibitors are part of targeted agents and are already in use in the clinic, especially for treatment of metastatic renal cell carcinoma. Distinct from conventional chemotherapeutics, targeted agents imply chronic treatment, which has changed our perspective on the commerce of adverse events (AE). In principle, mTOR-inhibitors are associated with a broad number of AEs. The occurrence of stomatitis, infection, pneumonitis, hyperlipidemia and hyperglycemia are considered major class effects of mTOR-inhibitors. However, severe adverse events remain scarce among mTOR-inhibitors and support chronic use of these agents. Based on their good clinical tolerability mTOR-inhibitors are prone to be developed in combinational therapies. However, the hepatic metabolism of these agents may limit their use to partners with a distinct metabolism in order to avoid drug interaction. Meanwhile about 40 different trials use mTOR-inhibitors in different tumor entities. The use of mTOR-inhibitors in neuroendocine tumors of the intestine, mantle cell lymphoma and sarcomas has hereby shown to be very promising. The mainstay of therapy already incorporates the use of everolimus in second line and temsirolimus in first line treatment in patients with metastatic renal cell carcinoma.

Topics: Animals; Antineoplastic Agents; Carcinoma, Renal Cell; Drug Interactions; Drug Therapy, Combination; Humans; Immunosuppressive Agents; Kidney Neoplasms; Neoplasm Metastasis; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

In the quest for personalized medicine, only a few biological parameters are routinely used to select patients prior to the initiation of anticancer targeted therapies, including mTOR inhibitors. Identifying biological factors that may predict efficacy or resistance to mTOR inhibitors represents an important challenge since rapalogs may exert antitumor effects through multiple mechanisms of action. Despite the fact that no such a factor is currently available, several molecular patterns are emerging, correlating with sensitivity and/or resistance to rapalogs. While activation of the phosphatidylinositol 3 kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, overexpression of cyclin D1, and functional apoptosis seem to sensitize tumor cells to rapalogs, Bcl2 overexpression or KRAS mutations are reported to be associated with resistance to mTOR inhibitors in several preclinical models. Translational research aimed at validating those parameters in clinical trials is ongoing.

Topics: Animals; Biomarkers, Tumor; Humans; Neoplasms; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases

The phosphatidylinositol 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway is vital for cell metabolism, growth, and proliferation. mTOR is frequently upregulated in many tumor types and hence has become an important target in cancer treatment. Sirolimus and its derivatives (rapalogs) interact with the intracellular receptor FK506 binding protein 12 (FKBP12), forming a complex with high affinity for mTOR and thus disrupting its activity. Rapalogs are being evaluated extensively in cancer patients with different formulations and schedules. Significant clinical activity has led to their approval for the treatment of kidney cancer, mantle cell lymphoma, and subependymal giant cell astrocytoma; however, despite increasing knowledge about cancer cell biology, their activity in other malignancies is unclear. Further research is needed to identify optimal dosage, administration and targeted combination as well as the subset of patients likely to respond to mTOR/PI3K inhibition. This review focuses on a discussion of the pathway, its implications in cancer biology and results of clinical trials of rapalogs alone or in combination, organizing them by common malignancy type.

Topics: Animals; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The activation of the phosphatidylinositol 3 kinase (PI3K)-Akt pathway is a known causal mechanism of oncogenesis and resistance to cancer treatments. The process of PI3K-Akt pathway activation is complex and includes receptor tyrosine kinase(RTK) activation, PIK3CA mutations, loss of phosphatase and tensin homolog (PTEN), Akt mutations, tuberous sclerosis complex (TSC) mutations, and Ras homologue enriched in brain (RHEB) gene amplifications. The blockage of mammalian target of rapamycin (mTOR), the key downstream pathway protein, has been successful in selected cancer types, with mTOR-targeting agents available for clinical use. Other novel drugs blocking this pathway such as PI3K inhibitors, Akt inhibitors and PDK-1 inhibitors are currently only available for investigational use, but have shown promise as cancer therapies in both preclinical and early phase clinical studies. The newer generations of these inhibitors are more specific and have improved potency and safety. The combinations of targeted treatments against this pathway, blocking multiple different steps, are under preliminary investigation. Further research is needed to identify the biomarkers that predict treatment response and resistance in order to optimize personalized medicine.

Topics: Animals; Humans; Molecular Targeted Therapy; Neoplasms; Oncogene Protein v-akt; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Signal Transduction; Sirolimus

Mammalian target of rapamycin (mTOR) is a conserved serine/threonine kinase that regulates cell cycle progression, protein translation, metabolism, and cellular proliferation. The mTOR pathway promotes cell proliferation under energy or nutrient-rich conditions by increasing ribosomal biogenesis and protein synthesis. Since enhanced activity of the mTOR pathway is frequently observed in malignant cells, inhibition of this kinase has become an attractive strategy to treat cancer. Rapamycin and its analogs temsirolimus, everolimus, and ridaforolimus referred to as "rapalogs" have demonstrated promising efficacy against renal cell carcinoma and are under investigation for the treatment of other malignancies. However, the emergence of drug resistance may ultimately limit the utility of rapalog therapy. Here we summarize the known mechanisms of resistance to mTOR-inhibitor therapy and describe potential strategies to overcome these for the current agents that target this pathway.

Topics: Antibiotics, Antineoplastic; Drug Resistance, Neoplasm; Humans; Molecular Targeted Therapy; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

mTOR exists in two distinct complexes. mTOR complex 1 (mTORC1) is potently inhibited by the immunosupressive macrolide rapamycin; whereas, mTORC2 is insensitive to this durg. These mTOR complexes play an integral role in the regulation of many cellular processes including protein synthesis, autophagy, lipid synthesis, mitochondrial metabolism/biogenesis, and cell cycle. Both mTOR complexes are important for maintaining cellular homeostasis and the growth of many types of cancer. Rapamycin and rapalogs have been effective in treating only a small number of these cancers, and other methods are being developed in order to address the short-comings of these drugs. The most direct of these approaches include ATP-competitive inhibitors of the mTOR kinase or dual inhibitors of both mTOR and PI3 kinase. However, other methods of inhibiting mTORC1 may prove clinically useful as well. These include amino acid depletion using asparaginase and inhibition of the Rheb GTPases with farnesyl transferase inhibitors or statins. Most excitingly, mTORC1 activation has been shown to cause and sensitize cells to DNA damage and ER stress. Many of the drugs currently used in the clinic for the treatment of cancer cause these types of stress, and existing drugs may be tailored to treat tumors with high mTORC1 activity.

Topics: Antibiotics, Antineoplastic; Drug Discovery; Gene Expression Regulation, Neoplastic; Humans; Molecular Targeted Therapy; Monomeric GTP-Binding Proteins; Neoplasms; Neuropeptides; Protein Kinases; Ras Homolog Enriched in Brain Protein; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Ridaforolimus (deforolimus; AP23573; MK-8669) is a novel sirolimus derivative manufactured by ARIAD Pharmaceuticals and acquired by Merck. It is a small-molecule kinase inhibitor of the mTOR in clinical development for the treatment of cancer. Both intravenous and oral formulations of the agent are being tested in cancer clinical trials. In preclinical and clinical studies, ridaforolimus exhibited significant antitumor activity with acceptable safety and tolerability. With single-agent ridaforolimus, mucositis and myelosuppression were dose-limiting toxicities. In advanced soft-tissue sarcoma, single-agent ridaforolimus was associated with a 29% clinical benefit rate and 2% partial response rate. A Phase III trial has recently been reported to have met its primary end point.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Drug Approval; Drug Evaluation, Preclinical; Humans; Neoplasms; Sarcoma; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates cell growth and metabolism in response to diverse external stimuli. In the presence of mitogenic stimuli, mTOR transduces signals that activate the translational machinery and promote cell growth. mTOR functions as a central node in a complex net of signaling pathways that are involved both in normal physiological, as well as pathogenic events. mTOR signaling occurs in concert with upstream Akt and tuberous sclerosis complex (TSC) and several downstream effectors. During the past few decades, the mTOR-mediated pathway has been shown to promote tumorigenesis through the coordinated phosphorylation of proteins that directly regulate cell-cycle progression and metabolism, as well as transcription factors that regulate the expression of genes involved in the oncogenic processes. The importance of mTOR signaling in oncology is now widely accepted, and agents that selectively target mTOR have been developed as anti-cancer drugs. In this review, we highlight the past research on mTOR, including clinical and pathological analyses, and describe its molecular mechanisms of signaling, and its roles in the physiology and pathology of human diseases, particularly, lung carcinomas. We also discuss strategies that might lead to more effective clinical treatments of several diseases by targeting mTOR.

Topics: Animals; Antibiotics, Antineoplastic; Cell Proliferation; Humans; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Phosphorylation; Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is a key regulator of cell growth and survival in mammalian cells. mTOR pathways are frequently dysregulated in various malignancies, providing targets for new anticancer drugs and therapeutic strategies. Here, we summarize the clinical experience of trials using the first generation of mTOR inhibitors, the rapalogs, and highlight the development of the next generation of catalytic inhibitors of the pathway.. mTOR inhibitors have shown major clinical activity in the treatment of renal cell carcinoma and two rapalogs have been approved for treatment of this malignancy. Recently, clinically significant trials with these agents were conducted in mantle cell lymphoma, pancreatic neuroendocrine tumors and astrocytomas. There are also promising results emerging in sarcomas, breast cancer and lung carcinoma. Multiple agents targeting mTOR, belonging to the new class of catalytic inhibitors with activity against both mTORC1 and mTORC2, are currently in various stages of preclinical and clinical development.. The rapalogs are the first mTOR inhibitors to show promising, yet modest, antitumor effects. To fully exploit the potential of targeting this pathway, it will be important to better understand the mechanisms of action and precise targets of the various inhibitors. Moreover, definition of biomarkers of susceptibility and identification of predictors and/or correlates to drug resistance will substantially advance this area.

Topics: Antineoplastic Agents; Hematologic Neoplasms; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR) is an atypical protein kinase that controls growth and metabolism in response to nutrients, growth factors and cellular energy levels, and it is frequently dysregulated in cancer and metabolic disorders. Rapamycin is an allosteric inhibitor of mTOR, and was approved as an immuno-suppressant in 1999. In recent years, interest has focused on its potential as an anticancer drug. However, the performance of rapamycin and its analogues (rapalogues) has been undistinguished despite isolated successes in subsets of cancer, suggesting that the full therapeutic potential of targeting mTOR has yet to be exploited. A new generation of ATP-competitive inhibitors that directly target the mTOR catalytic site display potent and comprehensive mTOR inhibition and are in early clinical trials.

Topics: Animals; Humans; Immunosuppressive Agents; Neoplasms; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases

Temsirolimus, an ester of sirolimus (rapamycin), selectively inhibits the kinase mammalian target of rapamycin and consequently blocks the translation of cell cycle regulatory proteins and prevents overexpression of angiogenic growth factors. Patients with advanced renal cell carcinoma (RCC) and a poor prognosis who received a once-weekly intravenous (IV) infusion of temsirolimus 25 mg, experienced significant survival benefits when compared with patients receiving standard interferon-alpha (IFNalpha) therapy in a large phase III clinical study. In this study, median overall survival was 10.9 vs. 7.3 months and objective response rates were 8.6% in temsirolimus recipients vs. 4.8% IFNalpha recipient group.Temsirolimus monotherapy recipients experienced significantly fewer grade 3 or 4 adverse events and had fewer withdrawals for adverse events than patients receiving IFNalpha.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Humans; Intracellular Signaling Peptides and Proteins; Neoplasms; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR) is a protein kinase of the PI3K/Akt signaling pathway. Activation of mTOR in response to growth, nutrient and energy signals leads to an increase in protein synthesis, which is required for tumor development. This feature makes mTOR an attractive target for cancer therapy. First-generation mTOR inhibitors are sirolimus derivatives (rapalogs), which have been evaluated extensively in cancer patients. Everolimus and temsirolimus are already approved for the treatment of renal-cell carcinoma. Temsirolimus is also approved for the treatment of mantle-cell lymphoma. These drugs, in addition to ridaforolimus (formerly deforolimus) and sirolimus, are currently being evaluated in clinical trials of various cancers. Second-generation mTOR inhibitors are small molecules that target the kinase domain, and have also entered clinical development. Clinical trials are underway to identify additional malignancies that respond to mTOR inhibitors, either alone or in combination with other therapies. Future research should evaluate the optimal drug regimens, schedules, patient populations, and combination strategies for this novel class of agents.

Topics: Antineoplastic Agents; Biomarkers, Tumor; Drug Design; Humans; Neoplasms; Phosphorylation; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Tumor cell migration is a key step in the formation of cancer metastasis. The mammalian target of rapamycin (mTOR), a highly conserved and ubiquitously expressed serinethreonine kinase, has been intensely studied for over a decade as a central regulator of cell growth, proliferation, differentiation, and survival. Recent data have shown that mTOR also plays a critical role in the regulation of tumor cell motility and cancer metastasis. Here, we briefly review recent advances regarding mTOR signaling in tumor cell motility. We also discuss recent findings about the mechanism by which rapamycin, a specific inhibitor of mTOR, inhibits cell motility in vitro and metastasis in vivo.

Topics: Animals; Cause of Death; Cell Line; Cell Movement; Humans; Insulin-Like Growth Factor I; Intracellular Signaling Peptides and Proteins; Ligands; Neoplasm Metastasis; Neoplasms; Protein Serine-Threonine Kinases; Receptor, IGF Type 1; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

mTOR (mammalian Target of Rapamycin) is the hub of the phosphoinositide 3-Kinase (PI3-K)→Akt→mTOR pathway, which is one of the most commonly mutated pathways in cancer. PI3-Ks and mTOR are related kinases which share an evolutionarily related kinase domain, although the former is a lipid kinase and the latter is a protein kinase. As a result of their similar ATP sites, the prototypical PI3-K inhibitors LY294002 and wortmannin inhibit both kinases, although the compounds have been primarily thought of as inhibitors of PI3-Ks. The widespread use of these reagents to understand PI3-K signaling and the likelihood that many of their effects are confounded by dual inhibition of PI3-K and mTOR make it essential to develop selective mTOR inhibitors in part to understand the unique cellular effects of inhibition of this key downstream component in the growth factor pathway. Rapamycin has historically provided a means for selective mTOR inhibition, yet it is not a typical ATP competitive inhibitor, making its effects difficult to reconcile with LY294002 and wortmannin. Several groups have recently reported pharmacological agents which inhibit mTOR but not PI3-K, providing a new pharmacological approach to selective mTOR inhibition. The TOR kinase domain inhibitors of mTOR have been termed TORKinibs to distinguish their mode of action from rapamycin and its analogs (rapalogs). These inhibitors bind to the ATP binding site of the kinase domain of mTOR and as a result inhibit both mTOR complexes, TORC1 (rapamycin sensitive) and TORC2 (rapamycin resistant). These molecules have allowed a reinvestigation of mTOR and in particular a reinvestigation of the mechanistic basis for incomplete proliferative arrest of cells by Rapamycin. A consensus has quickly emerged from the study of various TORKinibs that Rapamycin is ineffective at blocking cell proliferation because it only partially inhibits the activity of mTORC1. The profound anti-proliferative effect of TORKinibs suggests that as the molecules enter the clinic they may be successful in the treatment of cancers where rapamycin has failed.

Topics: Animals; Cell Proliferation; Enzyme Activation; Humans; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase Inhibitors; Proteins; Proto-Oncogene Proteins c-akt; Sirolimus; TOR Serine-Threonine Kinases

Contrasting with the broad activation of the PI3K/AKT/mammalian target of rapamycin (mTOR) survival pathway in most cancer, activity of rapalogues appears to be restricted to a few tumor types.. The analysis of molecular activity of the PI3K/AKT/mTOR pathway and resistance mechanisms of rapamycin and rapalogues led to the development of several inhibitory molecules.. New anticancer agents including PI3K inhibitors, dual PI3K/mTOR inhibitors, specific mTOR inhibitors, and AKT inhibitors may have direct inhibitory effects on targets by competing with ATP or may be non-ATP-competitive allosteric modulators of protein functions. In addition, another way of blocking the abnormal activation of the PI3K/AKT/mTOR pathway may be achieved by using HSP90 inhibitors. In this paper we review novel drugs inhibiting the mTOR signaling pathway.. Several trials are ongoing with novel drugs targeting key kinases involved in the mTOR pathway. Benchmarking those agents with rapalogues in rationally designed preclinical models and conceiving clinical trials in everolimus/temsirolimus-sensitive tumor types may help to identify drugs with a real clinical potential. Understanding mechanisms associated with primary and acquired resistance to rapalogues may help to enlarge indications and provide a rationale for designing combinations that will minimize the risk of developing resistance to rapalogues.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Clinical Trials as Topic; Drug Discovery; Humans; Intracellular Signaling Peptides and Proteins; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Protein Kinases; Protein Serine-Threonine Kinases; Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Prognosis after cardiac transplantation continues to improve with long-term outcomes limited by malignancy and coronary allograft vasculopathy (CAV). Everolimus may potentially reduce these late term complications, while maintaining the low cellular rejection rates seen with standard therapy.. Multiple studies have demonstrated the efficacy of everolimus in reducing acute rejection in heart transplant patients, progression and development of CAV, and the prevention and treatment of common malignancies, including skin cancer and Kaposi sarcoma. This review re-examines these studies with a focus on patient tolerability and safety.. Tolerability and safety of everolimus remain a concern with pneumonitis, effusions, mouth ulcers, edema and impaired wound healing associated with morbidity and mortality. Studies have repeatedly demonstrated renal function deterioration with concomitant everolimus and a standard dose calcineurin inhibitor (CNI). This impact can be partly reduced with CNI dose reduction without an increase in the rate of rejection.. If future studies confirm reduced CAV and malignancy rates, everolimus will become an important agent in de novo and maintenance immunotherapy in cardiac transplantation. Patient centered immunotherapy is preferred to protocol-based immunotherapy as it allows tailoring of immune therapy to each individual patient's rejection risk and side profile.

Topics: Animals; Disease Susceptibility; Dyslipidemias; Everolimus; Graft Rejection; Heart Transplantation; Humans; Immunocompromised Host; Immunosuppressive Agents; Kidney Diseases; Lung Diseases; Mice; Multicenter Studies as Topic; Neoplasms; Postoperative Complications; Randomized Controlled Trials as Topic; Sirolimus; TOR Serine-Threonine Kinases; Vascular Diseases; Wound Healing

Mammalian target of rapamycin (mTOR) is a central controller of cell growth, proliferation, metabolism and angiogenesis. mTOR signaling is often dysregulated in various human diseases and thus attracts great interest in developing drugs that target mTOR. Currently it is known that mTOR functions as two complexes, mTOR complex 1/2 (mTORC1/2). Rapamycin and its analogs (all termed rapalogs) first form a complex with the intracellular receptor FK506 binding protein 12 (FKBP12) and then bind a domain separated from the catalytic site of mTOR, blocking mTOR function. Rapalogs are selective for mTORC1 and effective as anticancer agents in various preclinical models. In clinical trials, rapalogs have demonstrated efficacy against certain types of cancer. Recently, a new generation of mTOR inhibitors, which compete with ATP in the catalytic site of mTOR and inhibit both mTORC1 and mTORC2 with a high degree of selectivity, have been developed. Besides, some natural products, such as epigallocatechin gallate (EGCG), caffeine, curcumin and resveratrol, have been found to inhibit mTOR as well. Here, we summarize the current findings regarding mTOR signaling pathway and review the updated data about mTOR inhibitors as anticancer agents.

Topics: Animals; Antineoplastic Agents; Biological Products; Cell Cycle; Cell Proliferation; Clinical Trials as Topic; Humans; Neoplasms; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Use of the mammalian target of rapamycin (mTOR) inhibitor rapamycin in organ transplantation has evolved through different phases over the past two decades. After its discovery in the mid 1970s, antifungal and cytotoxic effects were the first of its properties to be explored, but the most significant advancement was found in its use as an immunosuppressive agent to reduce transplant rejection. This was viewed as an important step forward for immunosuppression, as early studies suggested that rapamycin was less nephrotoxic than calcineurin inhibitors (CNIs). Later, detrimental effects of rapamycin on kidney function were found in some patients. Nonetheless, a fascination with the mTOR pathway and its central role in multiple cellular processes has ensued. Among the potential positive clinically relevant effects is rapamycin's capacity to interfere with fibrotic processes that often accompany transplant rejection, and to influence the preferential development of immunological tolerance. A feature of increasing importance is that the mTOR pathway is central for vital aspects of tumor development, including angiogenesis and cell growth; rapamycin, therefore, has anticancer activities, which may prove critical in the fight against high cancer rates in transplant recipients. The final chapters defining the value of rapamycin have not been written yet, and indeed remain a work in progress. Only further research will reveal the full potential of rapamycin in organ transplantation.

Topics: Animals; Fibrosis; Graft Rejection; Graft Survival; Humans; Immunosuppressive Agents; Kidney; Neoplasms; Organ Transplantation; Sirolimus; TOR Serine-Threonine Kinases; Transplantation Tolerance

Everolimus, a proliferation signal inhibitor in the mammalian target of rapamycin (mTOR) drug class, has many clinical applications, including in organ transplantation, oncology, and cardiology. It currently has United States Food and Drug Administration (FDA) approval for prophylaxis against rejection in de novo renal transplant recipients, treatment of renal cell carcinoma, and use as a drug-eluting stent. To review the pharmacology, pharmacokinetics, efficacy, and safety of everolimus, we performed a search of the MEDLINE database (January 1997-April 2010) for all English-language articles of in vitro and in vivo studies that evaluated everolimus, as well as abstracts from recent scientific meetings and the manufacturer. In transplantation, everolimus demonstrates immunosuppressive properties and has been used to prevent acute rejection in cardiac, liver, lung, and renal transplant recipients. It appears that this agent may be potent enough to allow for the minimization or removal of calcineurin inhibitors in the long-term management of renal transplant recipients. In oncology, everolimus has been proven effective for the management of treatment-resistant renal cell carcinoma. In cardiology, everolimus is available as a drug-coated stent and is used in percutaneous coronary interventions for prevention of restenosis. In transplant recipients and patients with renal cell carcinoma, everolimus appears to have an extensive adverse-event profile. The pharmacologic properties of everolimus differentiate this agent from other drugs used in these clinical areas, and its pharmacokinetic properties differentiate it from sirolimus.

Topics: Drug Interactions; Drug Monitoring; Drug-Eluting Stents; Everolimus; Graft Rejection; Humans; Immunosuppressive Agents; Neoplasms; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Ridaforolimus (AP23573; MK 8669) is an analog of sirolimus and a small molecule inhibitor of the mammalian target of rapamycin for the treatment of cancer. Both intravenous and oral formulations of the compound are being tested in clinical trials for the treatment of soft-tissue and bone sarcomas. It is in phase III development for sarcoma in the EU and US, and phase II for breast cancer, endometrial cancer, non-small cell lung cancer, and prostate cancer in the US and other markets in the world. This review discusses the key development milestones and therapeutic trials of this drug.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Drug Screening Assays, Antitumor; Drugs, Investigational; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

The risk of renal transplant recipients developing a malignancy is increasingly recognized as a major issue impacting long-term overall survival. As immunosuppression is thought to contribute to the development of cancer but is therapeutically required to protect against kidney rejection, reducing cancer in this setting is a challenging objective. An important question is whether there is a selective difference between pharmacological immunosuppressants regarding effects on malignancy. Both experimental and clinical studies thus far suggest that calcineurin inhibitors tend to promote tumor development; mycophenolic acid prodrugs such as mycophenolate mofetil have exhibited some capacity to inhibit tumors, but the concentrations needed for this effect are well above levels sustainable in transplant recipients. In contrast to these immunosuppressive substances, despite its potent immunosuppressive effects, rapamycin has demonstrated an impressive ability to inhibit de novo tumor development, as well as reduce tumor growth once cancer is already established. The antitumor effects of rapamycin are being studied extensively and appear to stem from the central role that the mammalian target of rapamycin molecule plays in basic cellular processes such as cell growth and proliferation, which are also essential for neoplasm development. Pilot trials and retrospective analyses of clinical data, especially using sirolimus, are highly suggestive that rapamycin can inhibit tumors in the clinical transplant setting. Prospective clinical trials are currently underway that will bring definitive answers as to whether rapamycin treatment can act simultaneously as an immunosuppressive and anticancer agent, with the aim of reducing the long-term problem of posttransplant malignancy.

Topics: Animals; Drug Therapy, Combination; Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Risk Assessment; Risk Factors; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

The long-term fate of renal transplant recipients has remained relatively unchanged over the last 15 years. The cumulative, chronic effects of immunosuppression contribute, to a great extent, to the higher, premature mortality rates linked to cardiovascular disease and malignancy observed in this patient population. Immunosuppression disrupts both antitumor surveillance and antiviral activities, and oncogenic viruses predispose to specific malignancies. Further, some drugs promote carcinogenesis by mechanisms independent of their immunosuppressive effects. In vitro studies have shown that calcineurin inhibitors (CNIs) promote tumor progression by a transforming growth factor-β-dependent mechanism. In contrast, in vivo mouse models have demonstrated that mammalian target of rapamycin (mTOR) inhibitors inhibit metastatic tumor growth and angiogenesis. The association between mTOR-inhibitor and reduced malignancy has been demonstrated in several studies. United Network for Organ Sharing registry data demonstrate that an mTOR-inhibitor either with or without a CNI, is associated with a reduced incidence of tumors compared to regimens that do not utilize mTOR-inhibitor Five years after renal transplantation, patients in the Rapamune Maintenance Regimen study who received sirolimus (SRL)-based CNI-free therapy after cyclosporine (CsA) withdrawal at 3 months showed a reduced incidence of malignancy compared with those who continued a regimen including (CsA) In the CONVERT study, patients who converted to SRL displayed a significantly lower malignancy rate (3.8%) at 24 months compared with those who continued CNI based therapy (11%; P < .001). A randomized, prospective study to evaluate the effect of conversion to SRL from a CNI, compared with continued CNI, showed that SRL was associated with a lower rate of nonmelanoma skin cancer (NMSC) and a longer time to first biopsy-confirmed new NMSC. An mTOR-inhibitor CNI-free regimen should be considered for transplant recipients at high risk for cancer development and for those who develop malignancies over the posttransplant course.

Topics: Animals; Calcineurin Inhibitors; Cyclosporine; Drug Therapy, Combination; Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Risk Assessment; Risk Factors; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Treatment Outcome

The biological function of the mammalian target of rapamycin (mTOR) and mechanisms of action of mTOR inhibitors currently available for clinical use are described.. mTOR is a target for anticancer agents due to its role in cancer development, progression, and resistance to other antineoplastic agents. Currently, two mTOR inhibitors, temsirolimus and everolimus, are approved for the treatment of patients with advanced renal cell carcinoma (RCC). Clinical trials comparing single-agent temsirolimus with interferon alfa-2a demonstrated an improvement in overall survival and progression-free survival (PFS) in patients with metastatic RCC. Clinical studies comparing everolimus with placebo indicated improved PFS in advanced RCC patients whose disease had progressed on or after vascular endothelial growth factor (VEGF) inhibitor therapy. Due to its role in the phosphatidylinositol 3-kinase (PI3K) signaling pathway, mTOR is a rational target for inhibition in combination with other agents, including traditional chemotherapy and agents that are affected by or target the PI3K pathway. Data from these studies review the use of mTOR inhibitors in non-Hodgkin's lymphoma and endometrial, breast, and neuroendocrine tumors. Common toxicities of mTOR inhibitors include mucositis, stomatitis, rash, asthenia, fatigue, and myelosuppression. Additional toxicities requiring monitoring include hyperglycemia, hyperlipidemia, and pneumonitis.. The mTOR signaling pathway is upregulated in a variety of solid and hematologic tumors. Two inhibitors of this pathway, temsirolimus and everolimus, have been approved for use in metastatic RCC. Although relatively safe, these drugs are associated with some unique adverse effects, such as hyperlipidemia, hyperglycemia, and pneumonitis, that require monitoring and may require clinical intervention.

Topics: Animals; Antineoplastic Agents; Drug Delivery Systems; Drug Design; Drug Monitoring; Drug Resistance, Neoplasm; Everolimus; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR) complex 1 (mTORC1) is a multicomponent, nutrient-sensitive protein that is implicated in a wide range of major human diseases. mTORC1 responds to both growth factors and changes in local amino acid levels. Until recently, the intracellular amino acid-sensing mechanism that regulates mTORC1 had remained unexplored. However, studies in human cells in culture have demonstrated that in response to amino acid stimulation, mTOR (a conserved member of the PI3K superfamily) is shuttled to late endosomal and lysosomal compartments, where it binds the Ragulator-Rag complex and is assembled into active mTORC1. Members of the proton-assisted amino acid transporter (PAT/SLC36) family have been identified as critical components of the amino acid-sensing system that regulates mTORC1 present in endosomal and lysosomal membranes. These discoveries not only highlight several new potential drug targets that could impact selectively on mTORC1 activity in cancer cells, but also provide novel insights into the strategies used by such cells to outcompete their neighbors in growth factor- and nutrient-depleted conditions. In this review, recent mechanistic insights into how mTORC1 activity is controlled by amino acids and the potential for the selective targeting this regulatory input are discussed.

Topics: Amino Acid Transport Systems; Amino Acids; Animals; Cytoplasm; Diptera; Humans; Intracellular Membranes; Lysosomes; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Nutritional Physiological Phenomena; Protein Binding; Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is a central regulator of cell growth and proliferation. mTOR signaling is frequently dysregulated in oncogenic cells, and thus an attractive target for anticancer therapy. Using CellDesigner, a modeling support software for graphical notation, we present herein a comprehensive map of the mTOR signaling network, which includes 964 species connected by 777 reactions. The map complies with both the systems biology markup language (SBML) and graphical notation (SBGN) for computational analysis and graphical representation, respectively. As captured in the mTOR map, we review and discuss our current understanding of the mTOR signaling network and highlight the impact of mTOR feedback and crosstalk regulations on drug-based cancer therapy. This map is available on the Payao platform, a Web 2.0 based community-wide interactive process for creating more accurate and information-rich databases. Thus, this comprehensive map of the mTOR network will serve as a tool to facilitate systems-level study of up-to-date mTOR network components and signaling events toward the discovery of novel regulatory processes and therapeutic strategies for cancer.

Topics: Antineoplastic Agents; Gene Regulatory Networks; Humans; Models, Biological; Neoplasms; Protein Interaction Mapping; Signal Transduction; Sirolimus; Systems Biology; TOR Serine-Threonine Kinases

FK506 binding proteins (FKBPs) are the intracellular ligands of FK506 and rapamycin, two natural compounds with powerful and clinically efficient immunosuppressive activity. In recent decades, a relevant role for immunosuppressants as anticancer agents has emerged. Especially, rapamycin and its derivatives are used, with successful results, across a variety of tumors. Of note, rapamycin and FK506 bind to FKBP12, and the resulting complexes interfere with distinct intracellular signaling pathways driven, respectively, by the mammalian target of rapamycin and calcineurin phosphatase. These pathways are related to T-cell activation and growth. Hyperactivation of the mammalian target of rapamycin (mTOR), particularly in cancers that have lost the tumor suppressor gene PTEN, plays an important pathogenetic role in tumor transformation and growth. The signaling pathway involving calcineurin and nuclear factors of activated T-lymphocytes is also involved in the pathogenesis of different cancer types and in tumor metastasis, providing a rationale for use of FK506 in anticancer therapy. Recent studies have focused on FKBPs in apoptosis regulation: Targeting of FKBP12 promotes apoptosis in chronic lymphocytic leukemia, FKBP38 knockdown sensitizes hepatoma cells to apoptosis, and FKBP51 silencing overcomes resistance to apoptosis in acute lymphoblastic leukemia, prostate cancer, melanoma, and glioma. Interestingly, derivatives of FK506 that have the same FKBP12-binding properties as FK506 but lack functional immunosuppressant activity, exert the same apoptotic effect as FK506 in chronic lymphocytic leukemia.These findings suggest that a direct FKBP inhibition represents a further mechanism of immunosuppressants.' anticancer activity. In this review, we focus on the role of FKBP members in apoptosis control and summarize the data on the antitumor effect of selective targeting of FKBP.

Topics: Antineoplastic Agents; Apoptosis; Humans; Immunosuppressive Agents; Neoplasms; Signal Transduction; Sirolimus; Tacrolimus; Tacrolimus Binding Proteins

Mammalian target of rapamycin (mTOR) is a key protein kinase controlling signal transduction from various growth factors and upstream proteins to the level of mRNA and ribosome with a regulatory effect on cell cycle progression, cellular proliferation and growth. TOR genes were discovered rather serendipitously while investigating the cause of resistance to immunosuppressant rapamycin in yeast. In normal cells, mTOR controls brilliantly the load of signals from its effectors resulting in a normal cell function. On the contrary, in various diseases and mainly in cancer this balance is lost due to mutations or overactivation of upstream pathways leading to a persistent proliferation and tumor growth. What makes mTOR attractive to researchers seems to be its key position which is on the crossroad of various signal pathways (Ras, PI3K/Akt, TSC, NF-kappaB) towards mRNA, ribosome, protein synthesis and translation of significant molecules, the uncontrolled production of which may lead to tumor proliferation and growth. Inhibition of mTOR by rapamycin (a natural product) or its analogs aims to prevent the deleterious effects of the abnormal signaling, regardless at which point of the signal pathway has the abnormality launched. Here, we will review the physiological functions of mTOR, its association to carcinogenesis and the latest evidence regarding the use of mTOR inhibitors in cancer treatment as well as future trends and aims of research.

Topics: Animals; Antineoplastic Agents; Humans; Neoplasms; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mTORC1 signaling pathway is a critical regulator of cell growth and is hyper activated in many different cancers. Rapamycin, an allosteric inhibitor of mTORC1, has been approved for treatment against renal cell carcinomas and is being evaluated for other cancers. Mechanistically, mTORC1 controls cell growth in part through its two well-characterized substrates S6K1 and 4E-BP1. In this review, we discuss the implications of a recent finding that showed differential inhibition of S6K1 and 4E-BP1 by rapamycin, leading to cell-type-specific repression of cap-dependent translation. We discuss potential mechanisms for this effect, and propose that mTOR-specific kinase inhibitors, instead of rapamycin, should be considered for mTOR-targeted cancer therapy.

Topics: Adaptor Proteins, Signal Transducing; Animals; Cell Cycle Proteins; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Humans; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Phosphoproteins; Protein Kinases; Proteins; Ribosomal Protein S6 Kinases; Signal Transduction; Sirolimus; Substrate Specificity; TOR Serine-Threonine Kinases; Transcription Factors

Epidemiological and experimental studies support an important role of the phosphoinosite 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway in the biology of human cancers. Over the past few years a number of components of this signaling cascade have been the subject of intense drug discovery activities. This article summarizes progress made in the identification of kinase inhibitors of PI3K and mTOR, with an emphasis placed on drugs currently undergoing clinical trials. Potential combination strategies, safety concerns, and resistance mechanisms for this new generation of anticancer agents are also discussed.

Topics: Antineoplastic Agents; Clinical Trials as Topic; Drug Discovery; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Rapamycin and its derivatives represent a unique set of pharmaceutical agents being employed across a broad range of therapeutic indications including organ transplantation, cardiovascular disease, the treatment of harmartomas, and cancer. In cancer this family of drugs is unique as it exploits tumor-associated changes in cell metabolism. mTOR complex 1 (mTORC1), a protein kinase complex, is the major target of rapamycin, and is a key element of evolutionarily conserved pathways that regulate cellular metabolism in response to environmental nutrients and intracellular energy status. Upstream mTOR regulatory proteins -- the TSC tumor suppressor, the Rheb proto-oncogene, the hVps34 phophatidylinositol kinase, and the Rag GTPases -- determine tumor growth, metabolism, and apoptosis susceptibility. Novel compounds that target mTOR and PI3K enzymes may further enhance the efficacy in inhibiting this pathway in a number of human pathologies, particularly cancer.

Topics: Amino Acids; Antibiotics, Antineoplastic; Cardiovascular Diseases; Clinical Trials as Topic; Humans; Immunosuppressive Agents; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Neurocutaneous Syndromes; Phosphatidylinositol 3-Kinases; Proteins; Proto-Oncogene Mas; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

The AMP-activated serine/threonine protein kinase (AMPK) is a sensor of cellular energy status found in all eukaryotes that is activated under conditions of low intracellular ATP following stresses such as nutrient deprivation or hypoxia. In the past 5 years, work from a large number of laboratories has revealed that one of the major downstream signalling pathways regulated by AMPK is the mammalian target-of-rapamycin [mammalian target of rapamycin (mTOR) pathway]. Interestingly, like AMPK, the mTOR serine/threonine kinase plays key roles not only in growth control and cell proliferation but also in metabolism. Recent work has revealed that across eukaryotes mTOR orthologues are found in two biochemically distinct complexes and only one of those complexes (mTORC1 in mammals) is acutely sensitive to rapamycin and regulated by nutrients and AMPK. Many details of the molecular mechanism by which AMPK inhibits mTORC1 signalling have also been decoded in the past 5 years. AMPK directly phosphorylates at least two proteins to induce rapid suppression of mTORC1 activity, the TSC2 tumour suppressor and the critical mTORC1 binding subunit raptor. Here we explore the molecular connections between AMPK and mTOR signalling pathways and examine the physiological processes in which AMPK regulation of mTOR is critical for growth or metabolic control. The functional conservation of AMPK and TOR in all eukaryotes, and the sequence conservation around the AMPK phosphorylation sites in raptor across all eukaryotes examined suggest that this represents a fundamental cell growth module connecting nutrient status to the cell growth machinery. These findings have broad implications for the control of cell growth by nutrients in a number of cellular and organismal contexts.

Topics: Adaptor Proteins, Signal Transducing; Aging; AMP-Activated Protein Kinase Kinases; AMP-Activated Protein Kinases; Animals; Antibiotics, Antineoplastic; Autophagy; Clinical Trials as Topic; Energy Metabolism; Humans; Intracellular Signaling Peptides and Proteins; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Protein Serine-Threonine Kinases; Proteins; Regulatory-Associated Protein of mTOR; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

A puzzling aspect of rapamycin-based therapeutic strategies is the wide disparity in the doses needed to suppress mTOR under different circumstances. A recent study revealing mechanistically how rapamycin suppresses mTOR provides two explanations for the differential sensitivities to rapamycin. First, mTOR exists as two functionally distinct complexes (mTORC1 and mTORC2), and while rapamycin suppresses both, it does so at very different concentrations. Whereas mTORC1 is suppressed by concentrations of rapamycin in the low nM range, mTORC2 generally requires low muM concentrations. Second, the efficacy of rapamycin is dependent on the level of phosphatidic acid (PA), which is required for the assembly of both mTORC1 and mTORC2 complexes. Rapamycin interacts with mTOR in a manner that is competitive with PA. Therefore, elevated levels of PA, which is common in cancer cells, increases the level of rapamycin needed to suppress both mTORC1 and mTORC2. A practical outcome of the recent study is that if PA levels are suppressed, mTORC2 becomes sensitive to concentrations of rapamycin that can be achieved clinically. Since mTORC2 is likely more critical for survival signals in cancer cells, the recent findings suggest new strategies for enhancing the efficacy of rapamycin-based therapeutic approaches in cancer cells.

Topics: Antibiotics, Antineoplastic; Clinical Trials as Topic; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Phospholipase D; Sirolimus; Transcription Factors

Targeted therapies are widely used in cancer because of their effectiveness, even in tumours that are resistant to conventional chemotherapy such as kidney or hepatocellular carcinomas. There are different families classified according to their mode of action. The antiangiogenics block tumor angiogenesis by acting on VEGF or its receptor. The main molecules are bevacizumab, sunitinib, and sorafinib. HER inhibitors work by blocking these receptors, which control different signaling intracellular pathways, and include an inhibitor of HER2, trastuzumab, and various inhibitors of HER1, or EGFR, including cetuximab, erlotinib, and gefitinib. Inhibitors of KIT, a membrane receptor, are mainly represented by imatinib, an inhibitor of tyrosine kinase. Finally, mTOR inhibitors act on the signaling pathway PI3K/AKT/mTOR, and key molecules are temsirolimus, everolimus, and deforolimus.

Topics: Angiogenesis Inhibitors; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Benzenesulfonates; Bevacizumab; ErbB Receptors; Erlotinib Hydrochloride; Everolimus; Gefitinib; Humans; Indoles; Kidney Neoplasms; Liver Neoplasms; Neoplasms; Niacinamide; Phenylurea Compounds; Pyridines; Pyrroles; Quinazolines; Receptor, ErbB-2; Receptors, Vascular Endothelial Growth Factor; Sirolimus; Sorafenib; Sunitinib; Vascular Endothelial Growth Factor A

The serine-threonine kinase mammalian target of rapamycin (mTOR) plays a major role in the regulation of protein translation, cell growth, and metabolism. Alterations of the mTOR signaling pathway are common in cancer, and thus mTOR is being actively pursued as a therapeutic target. Rapamycin and its analogs (rapalogs) have proven effective as anticancer agents in a broad range of preclinical models. Clinical trials using rapalogs have demonstrated important clinical benefits in several cancer types; however, objective response rates achieved with single-agent therapy have been modest. Rapalogs may be more effective in combination with other anticancer agents, including chemotherapy and targeted therapies. It is increasingly apparent that the mTOR signaling network is quite complex, and rapamycin treatment leads to different signaling responses in different cell types. A better understanding of mTOR signaling, the mechanism of action of rapamycin, and the identification of biomarkers of response will lead to more optimal targeting of this pathway for cancer therapy.

Topics: Biomarkers; Clinical Trials as Topic; Humans; Neoplasms; Patient Selection; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is an intracellular protein with a key role in cellular protein synthesis and energy balance that influences many aspects of cell growth and proliferation, including differentiation, cell-cycle progression, angiogenesis, protein degradation and apoptosis. mTOR can be activated by numerous oncogenic signals, such as growth factor activation through the EGF, IGF and VEGF receptors, mutation and silencing of the PTEN tumor suppressor gene, activating mutations in the PI3K catalytic subunit, Akt amplification and the Ras-Raf-MEK pathway. Once activated, the cellular functions of mTOR are achieved through its downstream targets, 4E-BP1 and p70S6K1. The mTOR pathway can be further regulated through a negative feedback loop, which may lead to resistance to specific inhibitors of mTOR. This review will outline the mTOR signaling pathway, which is often activated in cancers and account for tumor proliferation and growth, highlight the rationale in targeting mTOR with a focus on the preclinical and clinical development of one of these inhibitors, deforolimus (AP23573, MK-8669), and discuss potential benefit and barriers to these agents being introduced in the clinic.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Humans; Neoplasms; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR) has emerged as an important target for cancer therapy. Rapamycin has a distinct, well-documented toxicity profile and most of the toxicity data has been reported in patients with organ transplantation. Newer mTOR inhibitors have slightly different pharmacokinetic properties, yet they present toxicity profiles similar to rapamycin. Most of these toxicities are mild to moderate in severity and can be managed clinically by dose modification and supportive measures. Mucositis and pneumonitis are the most commonly reported toxicities, but they rarely lead to treatment discontinuation. Pathogenesis of pneumonitis is uncertain, but various hypotheses have been suggested, including cell-mediated immune response to the drug.

Topics: Animals; Antineoplastic Agents; Drug Hypersensitivity; Graft Rejection; Humans; Mucositis; Neoplasms; Organ Transplantation; Pneumonia; Prognosis; Protein Kinases; Sirolimus; Th1 Cells; Th2 Cells; TOR Serine-Threonine Kinases; Treatment Outcome

The phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin-pathway (PI3K/AKT/mTOR-pathway) plays a role in the regulation of cell proliferation, cell survival, angiogenesis and resistance to anti-tumor treatments. In many tumor types the PI3K/AKT/mTOR-pathway is found activated through several different underlying mechanisms. Since this pathway is believed to largely drive the malignant behavior of several of these tumors, mTOR-inhibition is considered an attractive means to apply as anti-tumor treatment. Currently, four mTOR-inhibitors are explored for clinical use: rapamycin, temsirolimus (CCI-779), everolimus (RAD001) and deforolimus (AP23573). As monotherapy, mTOR-inhibitors yield interesting anti-tumor activity against various tumor types at the expense of relatively mild toxicities. This recently resulted in the registration of two mTOR-inhibitors for patients with metastatic renal cell carcinoma (RCC) while randomized studies in other tumors are currently in progress. Furthermore, mTOR-inhibitors are well-suited drugs to combine with other anti-tumor drugs as in preclinical models mTOR-inhibition overcomes chemoresistance. Consequently, mTOR-inhibitor-containing multidrug regimens are subject to clinical studies. As holds true for all anti-tumor therapies, identification of patients who are likely to respond to mTOR-inhibitor-containing therapies is of utmost importance to avoid over- or undertreatment. Preliminary results suggest that several factors reflecting activation of mTOR in tumors may be used for this purpose. This review addresses the mechanism of action and current clinical experience with mTOR-inhibitors as well as their role in overcoming resistance to conventional therapies. Additionally, potential predictors of outcome to mTOR-inhibition are discussed.

Topics: Cell Division; Cell Survival; Clinical Trials as Topic; Drug Resistance, Neoplasm; Everolimus; Gene Amplification; Humans; Neoplasms; Neovascularization, Pathologic; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

The phosphatidylinositol-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway plays a critical role in the regulation of cellular growth, survival, and proliferation. Inappropriate activation of PI3K/Akt/mTOR signaling can promote a cellular environment that is favorable for transformation. In fact, dysregulation of this pathway, as a result of genetic mutations and amplifications, is implicated in a variety of human cancers. Therefore, mTOR has emerged as a key target for the treatment of cancer, particularly in the treatment of tumors that exhibit increased mTOR signaling as a result of genetic lesions. The immunosuppressant sirolimus (rapamycin) directly inhibits mTOR activity and suppresses the growth of cancer cells in vitro and in vivo. As a result, a number of sirolimus derivatives have been developed as anti-cancer therapies, and these compounds are currently under investigation in phase I-III clinical trials. In this review, we summarize the use of sirolimus derivatives in clinical trials and address some of the challenges associated with targeting mTOR for the treatment of human cancer.

Topics: Animals; Antibiotics, Antineoplastic; Antineoplastic Agents; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The importance of angiogenesis in tumour growth and development is well known. Overexpression of vascular endothelial growth factor (VEGF), the key mediator of angiogenesis, is associated with poor prognosis in cancer. As a result, several therapeutic agents that inhibit the actions of VEGF or its receptors are currently in development for use in advanced solid tumours, such breast, colorectal, lung and renal cancer. Clinical data from trials of anti-VEGF agents in this group of tumours are discussed, with a particular focus on the efficacy and safety of bevacizumab, the anti-VEGF agent at the most advanced stage of development in those tumour types. Future potential uses of bevacizumab in cancer therapy will be discussed.

Topics: Angiogenesis Inhibitors; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzenesulfonates; Bevacizumab; Clinical Trials as Topic; Combined Modality Therapy; Drug Delivery Systems; Forecasting; Humans; Indoles; Neoadjuvant Therapy; Neoplasm Proteins; Neoplasms; Neovascularization, Pathologic; Niacinamide; Phenylurea Compounds; Protein Kinase Inhibitors; Pyridines; Pyrroles; Receptors, Vascular Endothelial Growth Factor; Sirolimus; Sorafenib; Sunitinib; Vascular Endothelial Growth Factor A

Temsirolimus, a highly specific inhibitor of mammalian target of rapamycin (mTOR), is a novel anticancer targeted therapy with a new mechanism of action. The prototype mTOR inhibitor, oral rapamycin, is poorly soluble and undergoes extensive first-pass metabolism, leading to low and potentially variable absorption and exposure. For some tumors, maximizing the bioavailability and dose intensity via intravenous (IV) administration may provide optimal clinical benefit. Temsirolimus is an ester analog of rapamycin that retains its potent intrinsic mTOR inhibitory activity while exhibiting better solubility for IV formulation. In the treatment of advanced renal cell carcinoma, temsirolimus is administered as a 30- to 60-minute IV infusion once weekly at a flat dose of 25 mg. This dosage results in high peak temsirolimus concentrations and limited immunosuppressive activity. Because temsirolimus is active and well tolerated, different dosages and schedules are being explored for other solid and hematologic malignancies, including mantle cell lymphoma. Temsirolimus exhibits a high volume of distribution that, together with IV administration, leads to extensive distribution into peripheral tissues. In addition, significant and protracted exposures are attained with sirolimus (rapamycin), the major equipotent metabolite of temsirolimus. Whereas temsirolimus and sirolimus are both metabolized by cytochrome P450 (CYP) 3A4, drug interaction studies with agents that induce or inhibit CYP3A4 activity indicate that exposure to the sirolimus metabolite is somewhat sensitive to pharmacokinetic (PK) drug interaction. Therefore, temsirolimus dose adjustments are warranted if coadministration cannot be avoided. Despite its complexity, the PK profile of IV temsirolimus is well characterized in cancer patients and provides a strong basis for its future study as a monotherapy or in combination with other anticancer agents.

Topics: Antineoplastic Agents; Carcinoma, Renal Cell; Clinical Trials, Phase I as Topic; Dose-Response Relationship, Drug; Drug Dosage Calculations; Drug Interactions; Humans; Kidney Neoplasms; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Since the discovery of rapamycin, considerable progress has been made in unraveling the details of the mammalian target of rapamycin (mTOR) signaling network, including the upstream mechanisms that modulate mTOR signaling functions, and the roles of mTOR in the regulation of mRNA translation and other cell growth-related responses. mTOR is found in two different complexes within the cell, mTORC1 and mTORC2, but only mTORC1 is sensitive to inhibition by rapamycin. mTORC1 is a master controller of protein synthesis, integrating signals from growth factors within the context of the energy and nutritional conditions of the cell. Activated mTORC1 regulates protein synthesis by directly phosphorylating 4E-binding protein 1 (4E-BP1) and p70S6K (S6K), translation initiation factors that are important to cap-dependent mRNA translation, which increases the level of many proteins that are needed for cell cycle progression, proliferation, angiogenesis, and survival pathways. In normal physiology, the roles of mTOR in both glucose and lipid catabolism underscore the importance of the mTOR pathway in the production of metabolic energy in quantities sufficient to fuel cell growth and mitotic cell division. Several oncogenes and tumor-suppressor genes that activate mTORC1, often through the phosphatidylinositol 3-kinase (PI3K)/AKT pathway, are frequently dysregulated in cancer. Novel analogs of rapamycin (temsirolimus, everolimus, and deforolimus), which have improved pharmaceutical properties, were designed for oncology indications. Clinical trials of these analogs have already validated the importance of mTOR inhibition as a novel treatment strategy for several malignancies. Inhibition of mTOR now represents an attractive anti-tumor target, either alone or in combination with strategies to target other pathways that may overcome resistance. The far-reaching downstream consequences of mTOR inhibition make defining the critical molecular effector mechanisms that mediate the anti-tumor response and associated biomarkers that predict responsiveness to mTOR inhibitors a challenge and priority for the field.

Topics: Animals; Antibiotics, Antineoplastic; Cell Proliferation; Drug Discovery; Humans; Models, Biological; Neoplasms; Protein Biosynthesis; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Activation of mammalian target of rapamycin (mTOR) signaling occurs in a wide variety of human tumors and can lead to increased susceptibility to mTOR inhibitors. Temsirolimus, a novel analog of rapamycin, has shown promising preclinical and early clinical anti-tumor activity in various solid and hematologic tumor types, either alone or in combination with chemotherapy or other targeted agents. Randomized phase III trials have already demonstrated significant clinical benefits of treatment with single-agent temsirolimus in advanced renal cell carcinoma and relapsed and/or refractory mantle cell lymphoma. Other malignancies studied in the phase I and II trial settings include glioblastoma, breast cancer, endometrial cancer, non-Hodgkin lymphomas, and multiple myeloma. This article reviews a comprehensive collection of the clinical trial results reported to date for temsirolimus in various solid and hematologic malignancies, as well as current strategies being tested in ongoing trials. The findings with temsirolimus in multiple tumors provide a valuable framework for future development of temsirolimus and other mTOR inhibitors.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Disease Models, Animal; Drug Evaluation, Preclinical; Hematologic Neoplasms; Humans; Neoplasms; Sirolimus

Topics: Angiogenesis Inhibitors; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antimetabolites, Antineoplastic; Antineoplastic Agents; Benzamides; Benzenesulfonates; Bevacizumab; Carcinoma, Hepatocellular; Carcinoma, Renal Cell; Deoxycytidine; Drug Delivery Systems; Gastrointestinal Stromal Tumors; Gemcitabine; Humans; Imatinib Mesylate; Indoles; Neoplasms; Niacinamide; Pancreatic Neoplasms; Phenylurea Compounds; Piperazines; Pyridines; Pyrimidines; Pyrroles; Sirolimus; Sorafenib; Sunitinib

A growing body of evidence suggests that everolimus might offer effective immunosuppressive activity together with antiproliferative effects that may address some of the unmet needs in the long-term therapeutic management of the post-transplant patient.. To summarize the emerging evidence for employing everolimus-based immunosuppression.. A systematic review was conducted of the Medline, Embase and Renal Health Library (Cochrane Collaboration) databases, and of the summary publications from international transplant meetings and congresses during 2000-2008.. This article summarizes this analysis, with special focus on the pharmacokinetic characteristics of everolimus and on the results of its use in renal transplantation. Some data has also been included about the efficacy of the drug in other solid organ transplantation and in tumours.. Everolimus is an immunosuppressant drug with proven efficacy in transplantation. When used in combination with cyclosporin, better results are obtained in renal function with low cyclosporin doses. Adverse events related to this drug are frequent and lead to moderate dropout rates.

Topics: Antineoplastic Agents; Clinical Trials as Topic; Cytomegalovirus Infections; Drug Monitoring; Everolimus; Graft Rejection; Graft Survival; Heart Transplantation; Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Organ Transplantation; Sirolimus; Treatment Outcome

Aging is associated with cancer, in particular with breast, prostate, colon, lung, stomach, bladder and skin cancer. This article discusses how aging predisposes one to cancer. In principle, inhibition of aging should delay cancer. But is it possible to slow aging? As recently proposed, the nutrient-sensing TOR (target of rapamycin) pathway is involved in cellular and organismal aging. In rodents, certain conditions that interfere with the TOR pathway slow aging and prevent cancer. Retrospective analysis of clinical data reveals that inhibitors of TOR prevent cancer in humans. This article envisions a potential clinical use of TOR inhibitors in order to slow aging and delay cancer.

Topics: Adult; Aged; Aging; Cell Cycle; Female; Humans; Incidence; Middle Aged; Models, Biological; Neoplasms; Protein Kinases; Retrospective Studies; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) protein complex functions as an integration center for various intracellular signaling pathways involving cell cycle progression, proliferation, and angiogenesis. These pathways are frequently dysregulated in cancer, and therefore mTOR inhibition is a potentially important antitumor target. Commercially available mTOR inhibitors include rapamycin (i.e., sirolimus) and temsirolimus. Other agents under investigation include everolimus and deforolimus. mTOR inhibition has been studied in various solid tumors, including breast, gynecologic, gastrointestinal, prostate, lung, and head and neck cancers. Studies have focused on mTOR inhibition as a monotherapy or in combination with other drugs based on the principle that inhibiting as many targets as possible reduces the emergence of drug resistance. Temsirolimus is currently the only mTOR inhibitor that is specifically labeled for treatment of solid tumors. However, preclinical studies and early-phase trials are rapidly evolving. Additionally, research is further defining the complicated mTOR pathways and how they may be disordered in specific malignancies. To address these issues, NCCN convened a task force to review the underlying physiology of mTOR and related cellular pathways, and to review the current status of research of mTOR inhibition in solid tumors.

Topics: Clinical Trials as Topic; Everolimus; Humans; Neoplasms; Practice Guidelines as Topic; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

mTOR was determined to be a promising anticancer target and several drug inhibitors of mTOR are currently in clinical development. Rapamycin (RAP) was the first mTOR inhibitor discovered. However, RAP has poor aqueous solubility and chemical stability and therefore its utilization at doses susceptible to produce an effect as an anticancer agent is limited. This represented the main rationale for developing new RAP analogs. The RAP analogs currently in clinical development as anticancer agents include temsirolimus (CCI-779), everolimus (RAD-001), and deforolimus (AP23573). These agents have demonstrated antiproliferative activity against a diverse range of malignancies in preclinical studies, and clinical evaluations have been very encouraging thus far. Deforolimus (AP23573), a non-RAP prodrug, has been tested in Phase I and II clinical trials and shows promising results in several tumor types including sarcoma. A Phase III study in patients with sarcoma is currently ongoing. The preclinical and clinical studies with deforolimus will be presented.

Topics: Animals; Clinical Trials as Topic; Everolimus; Humans; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR), a serine/threonine kinase, is a mediator in the downstream signalling pathway phosphatidylinositol 3-kinase/Akt, playing a key role in regulation of basic cellular functions including growth and cell proliferation. The inhibitor of mTOR RAD001, or everolimus (Novartis Pharma AG), is a hydroxyethyl ether rapamycin derivative administered orally. Everolimus showed an important anti-angiogenic and antiproliferative activity on cell lines derived from human tumours and on xenograft models of human tumours. This molecule appears well tolerated, with skin reactions, stomatitis, myelosupression and metabolic abnormalities transient and reversible with interruption of treatment. Clear data suggest antitumor activity, including tumour regression and prolonged stable disease, which has been reported in patients with a variety of malignancies, especially those with metastatic renal cell cancer. Here, we review the preclinical data of this compound with current clinical results and future developments.

Topics: Antineoplastic Agents; Clinical Trials as Topic; Everolimus; Humans; Neoplasm Proteins; Neoplasms; Protein Kinases; Radiation-Sensitizing Agents; Sirolimus; TOR Serine-Threonine Kinases

Targeting mTOR complex 1 (mTORC1), which regulates general protein translation, represents one of the most attractive approaches to treating cancer, since upregulation of this pathway is a common hallmark in many tumors. Nevertheless, the use of rapamycin and its analogs in the clinic has revealed that mTORC1 pathway is embedded in a network of signaling cross-talks and feedbacks which might reduce its effectiveness in cancer. We have recently described a novel signaling feedback stemming from mTORC1 inhibition, which leads to the activation of ERK-MAPK (MAPK) pathway. The observation that MAPK is activated by rapamycin and its analogs in vitro, in mouse models, and cancer patient biopsies sets the rationale for the combined use of MAPK and mTORC1 inhibitors in cancer therapy. In this extra-view, we integrate our findings into the mTORC1 signaling network and discuss its relevance for the design of combinatorial therapies with mTORC1 inhibitors.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Enzyme Inhibitors; Feedback, Physiological; Humans; MAP Kinase Signaling System; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Neoplasms; Phosphatidylinositol 3-Kinases; Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

The mammalian target of rapamycin (mTOR) is responsive to numerous extracellular and intracellular cues and, through the formation of two physically and functionally distinct complexes, has a central role in the homeostatic control of cell growth, proliferation and survival. Through the aberrant activation of mTOR signaling, the perception of cellular growth signals becomes disconnected from the processes promoting cell growth, and this underlies the pathophysiology of a number of genetic tumor syndromes and cancers. Here, we review the oncogenes and tumor suppressors comprising the regulatory network upstream of mTOR, highlight the human cancers in which mTOR is activated and discuss how dysregulated mTOR signaling provides tumors a selective growth advantage. In addition, we discuss why activation of mTOR, as a consequence of distinct oncogenic events, results in diverse clinical outcomes, and how the complexity of the mTOR signaling network might dictate therapeutic approaches.

Topics: Animals; Antibiotics, Antineoplastic; Humans; Intracellular Signaling Peptides and Proteins; Models, Biological; Neoplasms; Protein Serine-Threonine Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Suppressor Proteins

Poxviruses demonstrate strict species specificity in vivo that range from narrow to broad, however the fundamental factors that mediate the basis of poxvirus tropism remain poorly understood. It is generally believed that most, if not all, poxviruses can efficiently bind and enter a wide range of mammalian cells and all of the known host anti-viral pathways that block viral replication in nonpremissive cells operate downstream of virus entry. A productive poxvirus infection is heavily dependent upon the production of a vast array of host modulatory products that specifically target and manipulate both extracellular immune response pathways of the host, as well as intracellular signal transduction pathways of the individually infected cells. The unique pathogenesis and host tropism of specific poxviruses can be attributed to the broad diversity of host modulatory proteins they express. Myxoma virus (MV) is a rabbit-specific poxviruses that encodes multiple host range factors, including an ankyrin-repeat protein M-T5, which functions to regulate tropism of MV for rabbit lymphocytes and some human cancer cells. At the molecular level, M-T5 binds and alters at least two distinct cellular proteins: Akt and cullin-1. The direct interaction between M-T5 and Akt was shown to be a key restriction determinant for MV tropism in a spectrum of human cancer cells making MV an excellent oncolytic candidate. Thus, the intricate relationship between viral encoded proteins and components of the host cell signaling networks can have profound impact on poxvirus tropism. The lessons we continue to learn from poxvirus host range factors like M-T5 will provide further insights into the factors that regulate poxvirus tropism and the mechanisms by which poxviruses micromanipulate the signaling pathways of the infected cell.

Topics: Animals; Ankyrin Repeat; Antibiotics, Antineoplastic; Cell Cycle Proteins; Cullin Proteins; F-Box Motifs; GTP-Binding Proteins; GTPase-Activating Proteins; Humans; Myxoma virus; Neoplasms; Oncolytic Virotherapy; Phosphorylation; Proto-Oncogene Proteins c-akt; Rabbits; Signal Transduction; Sirolimus; Viral Proteins

Cancer morbidity and mortality are increasingly apparent risks in transplant recipients, thus reducing life quality and overall survival. These risks have largely been attributed to long-term immunosuppressive drug therapy, which remains necessary to prevent organ allograft rejection. Interestingly, however, recent studies challenge the premise that all immunosuppressive drugs necessarily promote cancer. A particular class of immunosuppressants, referred to as mammalian target of rapamycin (mTOR) inhibitors, has been shown to have potent anti-cancer effects that are presently being tested in clinical studies. The focus of this review is to present current evidence that allows us to understand better the dual immunosuppressive and anti-cancer functions of this class of drugs used to prevent allograft rejection. We will concentrate on the different functions of mTOR that allow it to simultaneously control the immune system and tumor development. We will also discuss results from current clinical studies that either support or refute this potential dualistic role.

Topics: Animals; Antibiotics, Antineoplastic; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Neoplasms; Postoperative Complications; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases; Transplantation Immunology

Antineoplastic agent-induced pulmonary toxicity is an important cause of respiratory failure. Although the incidence of antineoplastic agent-induced pulmonary toxicity seems to be low, more cases can be expected, with increasing numbers of patients receiving the new generations of antineoplastic agents. Antineoplastic agents have previously been associated with bronchospasm, hypersensitivity reactions, venous thromboembolism, and pulmonary hemorrhage. Physicians should be aware of the clinical and radiographic presentations of the pulmonary toxicities associated with the newer antineoplastic agents. The approach to diagnosis, risk factors, and possible mechanisms of antineoplastic agent-induced pulmonary toxicity are discussed in this article.

Topics: Antibiotics, Antineoplastic; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antimetabolites, Antineoplastic; Antineoplastic Agents; Bevacizumab; Deoxycytidine; Doxorubicin; Epirubicin; Etoposide; Everolimus; Gemcitabine; Humans; Lung; Lung Diseases; Mitoxantrone; Neoplasms; Pneumonia; Pyrimidines; Risk Factors; Sirolimus; Teniposide; Trastuzumab

Topics: Animals; Antineoplastic Agents; Humans; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Post-transplant malignancy morbidity and mortality are important limitations in kidney transplantation. The incidence of malignancy has been estimated at 20% after 10 years of chronic immunosuppression. The aetiology of post-transplant malignancy is multifactorial, with the increased risk for malignancy in transplant recipients correlating with overall exposure to immunosuppression. Strategies to understand and minimize the risk of developing malignancy in the transplant population are needed. Calcineurin inhibitors (CNIs) have been linked with post-transplant malignancies, while mammalian target of rapamycin (mTOR) inhibitors have shown antineoplastic activities. The dual efficacy of sirolimus as an immunosuppressive and antitumour agent has been demonstrated experimentally and clinically. Clinical studies have demonstrated a lower incidence of new malignancies after renal transplantation in recipients receiving immunosuppression with mTOR inhibitors compared with CNIs. Therapeutic protocols involving mTOR inhibitors may protect an allograft from immunological rejection, while at the same time addressing the problem of cancer in this high-risk population. Newer sirolimus analogues, such as temsirolimus, have become a focus in pure oncological research and are being evaluated for antineoplastic effects on a variety of malignancies in clinical trials.

Topics: Antineoplastic Agents; Calcineurin Inhibitors; Clinical Trials as Topic; Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Sirolimus

Recent work has shown that the mTOR (mammalian target of rapamycin) pathway is an integral cell growth regulator. The mTOR pathway involves two functional complexes, TORC1 and TORC2, which have been defined by both their association with raptor or rictor, respectively, and their sensitivity to short-term rapamycin inhibition. Loss of tumor suppressors TSC1 or TSC2 leads to aberrant activation of TORC1, which has been implicated in the control of cell size. As a result, both physiologic and pathologic tissue hypertrophy are associated with TORC1 activation. Some clinical examples include skeletal and cardiac muscle hypertrophy, vascular restenosis, and compensatory nephrotic hypertrophy. Clarification of the mTOR pathway may lead to increased understanding of both the etiology and consequences of aberrant cell size regulation. This review covers some of the biochemical regulation of the mTOR pathway that may be important to the regulation of cell size, and it will present several potential clinical applications where the control of cell size may be biologically significant.

Topics: Antibiotics, Antineoplastic; Cell Size; Humans; Hypertrophy; Muscles; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

The proliferation signal inhibitors [PSIs; mammalian target of rapamycin (mTOR) inhibitors] are widely used for immunosuppression in transplant recipients. Alongside their immunosuppressive properties, PSIs also have substantial anti-neoplastic activity, as a result of their inhibition of cellular signalling pathways involved in critical functions such as cell division, T-cell activation, invasion and growth factor production. In vitro and in vivo studies have shown that PSIs can prevent the growth of experimentally transformed cells and tumour-derived cell lines, and can also increase the sensitivity of cells to apoptosis-inducing agents. The mechanisms of anti-tumour activities of PSIs identified in pre-clinical studies include up-regulation of adhesion molecules with reversion to less invasive phenotypes, and inhibition of angiogenesis resulting from both decreased vascular endothelial growth factor production and decreased endothelial sensitivity to such growth factors. In clinical trials of PSIs in transplant recipients, results show that the incidence of malignancies is substantially lower in patients receiving PSIs than in those receiving calcineurin inhibitor (CNI)-based immunosuppression, with significantly longer times to the development of malignancy. This protective effect of the PSIs is also present in patients receiving combination therapy with a CNI and a PSI. There is also evidence to suggest a role for PSIs in the management of post-transplantation malignancy, with reports of complete resolution of primary and metastatic tumours after conversion from a CNI to a PSI. These beneficial effects have led to the investigation of everolimus and an analogue of sirolimus as a treatment for patients with advanced solid tumours.

Topics: Animals; Calcineurin Inhibitors; Cyclosporine; Humans; Immunosuppressive Agents; Kidney Transplantation; Lymphoproliferative Disorders; Neoplasms; Protein Kinases; PTEN Phosphohydrolase; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Autophagy is a dynamic process of subcellular degradation, which has recently sparked great interest as it is now recognized to be involved in various developmental processes and various diseases including cancer and neurodegeneration. Autophagy can function as a cytoprotective mechanism; however, it also has the capacity to cause cell death. A better understanding of autophagy is needed to allow its manipulation for therapeutic purposes, and new insights into the molecular mechanisms of autophagy are now leading to the discovery of exciting new potential drug targets.

Topics: Animals; Antibiotics, Antineoplastic; Autophagy; Humans; Neoplasms; Neurodegenerative Diseases; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Since the introduction of cyclosporin A (CsA) in the early 1980s, the use of immunosuppressants has markedly increased. Already established drugs have proved effective in the treatment of a wide range of diseases outside transplantation medicine and new immunosuppressants have been developed for more specific indications such as psoriasis and atopic dermatitis. Patients in transplantation medicine as well as in dermatology have benefited significantly from systemic and topical application of both new and established drugs. But are these drugs without risks? Cancer-protecting effects have been reported for some of the available immunosuppressants. Conversely, other publications and the issue of a black box warning by the US Food and Drug Administration have increased concerns about cancer-promoting effects. Knowledge of the specific effects as well as adverse effects is paramount to ensure an application that is safe and beneficial for the patient. Here we review the mechanisms of action and therapeutic potential, and critically review recent literature with respect to possible carcinogenic side effects of systemic and topical CsA, tacrolimus, pimecrolimus and rapamycin.

Topics: Calcineurin Inhibitors; Carcinogens; Cyclosporine; DNA Repair; Humans; Immunosuppressive Agents; Models, Biological; Neoplasms; Protein Kinases; Sirolimus; Tacrolimus; TOR Serine-Threonine Kinases; Ultraviolet Rays

Increasing success in renal transplantation and longer patient survival has meant that post-transplant malignancies are having an increasing impact on long-term graft and patient survival. Choice of the immunosuppressive agents provides one of the controllable risk factors for the development of malignancies in this population. Calcineurin inhibitors (CNIs) are associated with an increased incidence of cancers, whereas the proliferation signal inhibitors (PSIs), everolimus and sirolimus have demonstrated anti-oncogenic effects in pre-clinical models and are currently being investigated as anti-cancer agents in clinical trials. There is increasing evidence demonstrating a lower incidence of post-transplant malignancies in renal transplant recipients receiving PSI-based immunosuppression compared with those receiving CNIs. Conversion from CNIs to PSIs has been shown to lead to the regression of Kaposi's sarcoma in renal transplant recipients and is now part of accepted standard care for this tumour in this setting. The anti-cancer properties of PSI-based regimens have the potential to combine the dual benefits of immunosuppression without the use of CNIs and the direct anti-oncogenic effects through their inhibition of the mammalian target of rapamycin (mTOR) signalling pathway. In the absence of formal clinical trial evidence on the best way to use PSIs in this setting, a workshop was held to provide practical guidance on immunosuppressive strategies in the context of malignancy, given the current state of knowledge.

Topics: Calcineurin Inhibitors; Everolimus; Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Radiation affects both tumor and normal tissues, limiting the total delivered radiation dose. Therefore, novel ways to exploit molecular targets and improve the therapeutic ratio are continually being investigated. Autophagy plays an important role in cancer cell death decisions, particularly in solid tumors. This is counterbalanced by its function in cellular energy preservation. Recent studies have attempted to exploit autophagy in order to improve therapeutic ratio. However, direct inhibition of autophagy has been demonstrated to promote cancer cell death or survival dependent on cell type and condition. The mammalian target of rapamycin (mTOR) also regulates autophagy, as well as cell survival and proliferation pathways. Therefore, inhibition at this level of signaling would represent an excellent therapeutic target as it would limit cell growth, decrease cell proliferation, and boost autophagocytosis. Current investigations of mTOR inhibitors in combination with radiation appear to potentiate radiation's ability to induce autophagy. Further studies are necessary to fully elucidate which tumors have the most robust induction of autophagy in response to mTOR inhibition and radiation.

Topics: Animals; Apoptosis; Autophagy; Cell Death; Humans; Neoplasms; Protein Kinases; Radiation-Sensitizing Agents; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Temsirolimus (CCI-779), a small molecule inhibitor of mTOR protein, is a water-soluble synthetic rapamycin ester that has been developed in both oral and intravenous (i.v.) formulations. PI3k/Akt/mTOR pathway activation is implicated in the pathogenesis of many cancers. Inhibition of mTOR protein abrogates pathway-mediated cellular transcription and translation, leading to cell cycle arrest, antiangiogenesis and apoptosis. The drug has significant in vitro antitumor effect against a number of cancer cell lines and has demonstrated in vivo cytostatic activity in xenograft models. Flat dosing of 25 mg, 75 mg and 250 mg i.v. weekly were selected for tumor-specific phase I trials. Biological activity was observed at all these doses. However, the frequency and intensity of the toxicities increased at higher doses and more high-dose patients had to reduce the dose or discontinue the drug. Notable temsirolimus-related toxicities include rash, mucostomatitis, diarrhea, hyperlipidemia, hyperglycemia and thrombocytopenia. Temsirolimus is farther along in clinical development than any other mTOR inhibitor in its class and has demonstrated significant activity in patients with poor-risk clear-cell renal cell carcinoma. Patients receiving temsirolimus alone achieved longer survival than those receiving interferon alone or temsirolimus plus interferon in a randomized phase III trial. Predictive biomarkers for clinical efficacy are undetermined and remain under investigation.

Topics: Antineoplastic Agents; Carcinoma, Renal Cell; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Drug Delivery Systems; Humans; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR) is a key downstream molecule of PI3K/Akt pathway. It integrates input signals from growth factors, nutrients and energy to regulate cell growth and proliferation via different cellular processes. Gene mutations of mTOR pathway-related proteins are very common in many carcinomas. Abnormal expression of these related proteins can result in aberrant hyperactivity of mTOR pathway. Therefore, mTOR-targeted therapy has shown promising role in the management of various cancers. This article reviewed the current status of researches on mTOR and its inhibitors in antitumor therapy.

Topics: Animals; Antineoplastic Agents; Everolimus; Humans; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Prolonged waiting times for renal transplantation, an increase in the average age of recipients, decreased acute rejection rates due to use of newer potent immunosuppressives and improving long-term transplant survival have raised concerns in the transplant community regarding posttransplant cancer. In view of the fact that transplant recipients are living longer, it is of paramount importance that we continue to translate discoveries at the bench to the bedside and document cancers in the posttransplant recipient registries. Analysis of data will help in optimizing patient management.. Recent evidence indicates that sirolimus is associated with a decreased incidence of posttransplant de-novo cancer and remission of Kaposi's sarcoma and nonmelanoma skin cancer. Mycophenolate mofetil has been shown to have an antiproliferative activity against leukemia and lymphoma and an anti-tumor effect against colon and prostate cancer. Clinically it has been shown to be associated with a reduced incidence of cancers like posttransplant lymphoproliferative disorder.. Appropriate selection of transplant candidates, pretransplant and posttransplant cancer surveillance and judicious evidence-based use of newer immunosuppressants may help reduce the incidence and improve the outcome of posttransplant cancer.

Topics: Humans; Immunosuppressive Agents; Kidney Transplantation; Mycophenolic Acid; Neoplasms; Population Surveillance; Sirolimus

Topics: Acute Disease; Animals; Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Humans; Kidney Transplantation; Leukemia; Neoplasms; Postoperative Complications; Sarcoma, Kaposi; Sirolimus

Recent successes using Gleevec for the treatment of chronic myelogenous leukemia and gastrointestinal stromal tumors have provided proof that strategies to target signal transduction pathways mutated in human cancers can work. However, the application of this strategy to other cancers has been slow. Central to alleviating this impedance is the molecular characterization of the tumors. There is an urgent need to translate basic scientific findings into relevant, clinically applicable molecular diagnostic assays.

Topics: Animals; Biomarkers, Tumor; Clinical Trials as Topic; Humans; Kidney Neoplasms; Models, Biological; Neoplasms; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

One of the most prominent pathways explored in the area of targeted therapy is the PI3K/Akt/mTOR pathway, which plays a central role in cell survival and proliferation. Deregulation of this pathway has been implicated in the promotion of cancer cell growth and survival. Inhibition of several steps of this pathway has been shown to confer favorable antitumor activity in a variety of cancer types. This article provides a brief analysis of the PI3K/Akt/mTOR pathway, its importance in tumor pathogenesis and the current status of preclinical and clinical studies targeting signaling components of this pathway.

Topics: Antibiotics, Antineoplastic; Cell Proliferation; Cell Survival; Cell Transformation, Neoplastic; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Mounting evidence links deregulated protein synthesis to tumorigenesis via the translation initiation factor complex eIF4F. Components of this complex are often overexpressed in a large number of cancers and promote malignant transformation in experimental systems. mTOR affects the activity of the eIF4F complex by phosphorylating repressors of the eIF4F complex, the eIF4E binding proteins. The immunosuppressant rapamycin specifically inhibits mTOR activity and retards cancer growth. Importantly, mutations in upstream negative regulators of mTOR cause hamartomas, haemangiomas, and cancers that are sensitive to rapamycin treatment. Such mutations lead to increased eIF4F formation and consequently to enhanced translation initiation and cell growth. Thus, inhibition of translation initiation through targeting the mTOR-signalling pathway is emerging as a promising therapeutic option.

Topics: Animals; Antibiotics, Antineoplastic; Cell Transformation, Neoplastic; Eukaryotic Initiation Factor-4E; Eukaryotic Initiation Factor-4F; Humans; Neoplasms; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Topics: Antibiotics, Antineoplastic; Clinical Trials, Phase II as Topic; Drug Design; Enzyme Inhibitors; Female; Humans; Male; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

In search of new strategies for the therapy of advanced tumors stroma-targeted approaches have been discussed recently, especially antiangiogenic therapies. It has turned out that some biomodulating drugs exhibit also effects against tumors beyond their original non-oncologic indication. Among these drugs are for example thalidomide,COX-2 inhibitors, PPARgamma agonists (thiazolidindiones) and mTOR antagonists (rapamycin). The antitumor efficacy of these therapeutics is fundamentally based on indirect effects on the stroma of the tumors. Combination therapies of these therapeutics seem to be superior to the use of single agents. These new biomodulating therapy approaches represent an interesting option for the palliative treatment of advanced tumors, especially as a supplement or extension of established chemo- and immunotherapeutic therapies, since they can be performed in an outpatient setting, the observed side effects are usually mild, and the therapies are therefore well accepted by the patients.

Topics: Animals; Antineoplastic Agents; Cyclooxygenase 2 Inhibitors; Drug Delivery Systems; Drug Design; Humans; Immunologic Factors; Neoplasms; Palliative Care; PPAR gamma; Practice Guidelines as Topic; Practice Patterns, Physicians'; Protein Kinases; Sirolimus; Stromal Cells; Thiazolidinediones; TOR Serine-Threonine Kinases; Treatment Outcome

The mammalian target of rapamycin (mTOR) is a threonine kinase involved in intracellular pro-survival signaling. Its activation leads to progression from the G1 to S phase of the cell cycle. Constitutive activation of the mTOR-related messengers, including phosphatidylinositol 3-kinase, Akt kinase, ribosomal p70S6 kinase and eukaryotic translation initiation factor 4E-binding protein kinase, was found in numerous malignancies. Recent data indicate that the mTOR kinase pathway can be an attractive target for anti-cancer drug development. A well-known mTOR inhibitor is rapamycin (RAPA), previously applied as an immunosuppressive agent in transplant studies. Recently, analogs of RAPA, such as CCI-779, RAD001 and AP23573, have been developed. All of those agents are currently being tested in patients with solid or hematological tumors in several clinical trials. This review presents recent developments in targeting the mTOR kinase pathway.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Drug Design; Enzyme Activation; Everolimus; Humans; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is involved in the control of cellular growth and proliferation. Abnormal activation of signaling pathways both proximal and distal to this kinase occurs frequently in human cancer, suggesting that mTOR is an attractive target for antineoplastic therapies. Rapamycin and its analogs inhibit mTOR and have demonstrated potent antitumor activity in vitro and in xenograft models. Several phase I and phase II clinical studies with rapamycin-like drugs have been conducted and have demonstrated antitumor activity in various types of refractory neoplasms. To date, mTOR inhibitors have been well tolerated at a wide range of doses, making the selection of phase II trial doses-based solely on toxicity criteria difficult. Assessment of the pharmacodynamic effects in surrogate tumor tissues has been used to determine the pharmacodynamically active doses. The lack of a parallel assessment of tumor tissue effects coupled with the intrinsically high interpatient variability has limited the value of these studies. A better understanding of markers that are predictive of response to mTOR inhibitors could be used for improved patient selection in clinical trials. mTOR inhibitors are promising anticancer agents; however, further studies are required to advance these drugs into the clinic. This review will describe the mTOR pathway and highlight its role as a potential drug target. Several mTOR inhibitors that are currently undergoing clinical development, and the challenges facing the development of inhibitors of this type, will also be discussed.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Everolimus; Humans; Neoplasms; Prodrugs; Protein Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

Everolimus is a novel immunosuppressive agent related to sirolimus. It is a proliferation signal inhibitor with an improved pharmacokinetic profile and bioavailability compared with sirolimus. Everolimus has been shown to be as effective as mycophenolate mofetil in reducing acute rejection in renal transplantation. In cardiac transplant recipients, it is superior to azathioprine in reducing acute rejection and cardiac allograft vasculopathy. Its use is also associated with a decrease in cytomegalovirus infection. However, coadministration with calcineurin inhibitors requires careful dose adjustment to prevent renal toxicity. Antiproliferative effects of everolimus may abrogate the increased risk of malignancy seen in solid organ transplantation.

Topics: Animals; Antineoplastic Agents; Cell Proliferation; Drug Administration Schedule; Everolimus; Graft Rejection; Heart Transplantation; Humans; Immunosuppressive Agents; Kidney Transplantation; Lung Transplantation; Neoplasms; Product Surveillance, Postmarketing; Randomized Controlled Trials as Topic; Sirolimus; Xenograft Model Antitumor Assays

Post-transplant de novo malignancies are reviewed in three time periods: (i) the azathioprine (AZA) era from 1962 to 1980-1981, (ii) the cyclosporine (CYA) era (1980 to present) in which the calcineurin inhibitors, CYA and tacrolimus (TAC), were the mainstay of recipient immunosuppression, and (iii) the TOR inhibitor era starting in the year 2000. Both transplant registry and transplant center reports on malignancies occurring in the AZA era are reviewed. Reports from transplant centers and from the Cincinnati Transplant Tumor Registry (CTTR) in both the early CYA era (1980s) and the 1900-2000 CYA era are reported. Cancer incidence associated with AZA versus CYA, CYA versus TAC, and AZA versus mycophenolate mofetil (MMF) is compared in both transplant center and registry reports including new, unreported Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) data from 1998 to 2003. The malignancy incidence associated with lymphocyte-depleting antibody and corticosteroid immunosuppression is discussed. Reduced malignancy incidence recently reported with TOR inhibitors is compared with that of conventional immunosuppression. Important nondrug factors influencing the incidence of post-transplant malignancies from seven single and three registry reports are detailed. The substantial role that de novo malignancies play in post-transplant mortality is discussed. Finally, management recommendations for recipients who develop de novo post-transplant malignancies are briefly presented.

Topics: Antilymphocyte Serum; Azathioprine; Cyclosporine; Europe; Female; History, 20th Century; History, 21st Century; Humans; Immunosuppressive Agents; Kidney Transplantation; Male; Neoplasms; Ohio; Registries; Sirolimus; Tacrolimus; United States

In this issue of Cancer Cell, Phung and coworkers demonstrate that sustained endothelial activation of Akt by expression of constitutively activated Akt1 (myrAkt1) leads to blood vessels that essentially recapitulate the complex structural and functional abnormalities of tumor vessels. The authors provide evidence that rapamycin inhibition of PI3K/Akt/mTOR signaling in endothelial cells (ECs), by either reducing Akt activity or blocking mTOR, reverses the pathologic effects associated with excess VEGF signaling in the tumor vasculature. However, unexpected findings following mTOR inhibition in vivo highlight the seemingly paradoxical and complex effects of rapamycin on various cell types within the tumor microenvironment.

Topics: Antibiotics, Antineoplastic; Endothelial Cells; Endothelium, Vascular; Enzyme Activation; Humans; Neoplasms; Neovascularization, Pathologic; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Cells, Cultured; Vascular Endothelial Growth Factor A

The serine/threonine kinase, mTOR (mammalian Target of Rapamycin) has become a focus for cancer drug development. Rapamycins are highly specific inhibitors of mTOR and potently suppress tumour cell growth by retarding cells in G1 phase or potentially inducing apoptosis. Currently, both rapamycin and several analogues are being evaluated as anticancer agents in clinical trials. Results indicate that many human cancers have intrinsic resistance and tumours initially sensitive to rapamycins become refractory, demonstrating acquired resistance. Here, we consider mechanisms of resistance to inhibitors of mTOR.

Topics: Cell Cycle; Drug Resistance, Neoplasm; Humans; Models, Biological; Molecular Structure; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR), a protein kinase of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, has a central role in controlling malignant cellular growth. As a result, mTOR is viewed as an important target for anticancer drug development. Inhibitors of mTOR currently under evaluation in cancer clinical trials are rapamycin (also known as sirolimus, Wyeth) and derivatives temsirolimus (CCI-779, Wyeth), everolimus, (RAD001, Novartis Pharma AG), and AP23573 (Ariad Pharmaceuticals). Preclinical studies suggest that sensitivity to mTOR inhibitors may correlate with activation of the PI3K pathway and/or with aberrant expression of cell cycle regulatory or anti-apoptotic proteins. Clinical trial results show that mTOR inhibitors are well tolerated and may induce prolonged stable disease and tumor regressions in cancer patients. Future research should evaluate optimal, schedule, patient selection, and combination strategies for this novel class of agents.

Topics: Antibiotics, Antineoplastic; Clinical Trials as Topic; Everolimus; Humans; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) is a key element of the PI3KAkt (protein kinase B) signalling pathway, responsible for the regulation of cell growth and proliferation. There are two main downstream messengers of the mTOR kinase, eukaryotic initiation factor 4E-binding protein-1 and the 40S ribosomal protein S6 kinase 1, that control translation and cell-cycle progression. Abnormal activation of the mTOR pathway occurs frequently in numerous human malignancies; therefore, mTOR represents an attractive target for anticancer drug development. Rapamycin and its analogues CCI-779, RAD-001 and AP-23573 are known specific inhibitors of the mTOR kinase. Several clinical Phase I/II trials showed their activity in solid tumours and haematological malignancies. Moreover, inhibitors of mTOR were found to synergise with some cytostatics or other biological agents, which seems to be a promising direction for future strategies of antitumour treatment.

Topics: Animals; Antineoplastic Agents; Drug Delivery Systems; Drugs, Investigational; Humans; Neoplasms; Sirolimus

Autophagy has been recognized as an important cellular process for at least 50 years; however, it is only with the recent identification of key regulators of autophagy (Atg genes) that we have begun a mechanistic exploration of its importance in cancer. Recent studies suggest that autophagy may be important in the regulation of cancer development and progression and in determining the response of tumor cells to anticancer therapy. However, the role of autophagy in these processes is complicated and may, depending on the circumstances, have diametrically opposite consequences for the tumor. In this article, we discuss recent discoveries regarding autophagy in cancer.

Topics: Animals; Antineoplastic Agents; Autophagy; Energy Metabolism; Humans; Lysosomes; Mice; Neoplasm Proteins; Neoplasms; Sirolimus; Tumor Suppressor Proteins

Proteins regulating the mammalian target of rapamycin (mTOR), as well as some of the targets of the mTOR kinase, are overexpressed or mutated in cancer. Rapamycin, the naturally occurring inhibitor of mTOR, along with a number of recently developed rapamycin analogs (rapalogs) consisting of synthetically derived compounds containing minor chemical modifications to the parent structure, inhibit the growth of cell lines derived from multiple tumor types in vitro, and tumor models in vivo. Results from clinical trials indicate that the rapalogs may be useful for the treatment of subsets of certain types of cancer. The sporadic responses from the initial clinical trials, based on the hypothesis of general translation inhibition of cancer cells are now beginning to be understood owing to a more complete understanding of the dynamics of mTOR regulation and the function of mTOR in the tumor microenvironment. This review will summarize the preclinical and clinical data and recent discoveries of the function of mTOR in cancer and growth regulation.

Topics: Animals; Antibiotics, Antineoplastic; Autophagy; Cell Hypoxia; Enzyme Activation; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Kinases; Sirolimus; Stem Cells; TOR Serine-Threonine Kinases

Identification of the key roles of protein kinases in signaling pathways leading to development of cancer has caused pharmacological interest to concentrate extensively on targeted therapies as a more specific and effective way for blockade of cancer progression. This review will mainly focus on inhibitors targeting these key components of cellular signaling by employing a technology-based point of view with respect to ATP- and non-ATP-competitive small molecule inhibitors and monoclonal antibodies of selected protein kinases, particularly, mammalian target of rapamycin (mTOR), BCR-ABL, MEK, p38 MAPK, EGFR PDGFR, VEGFR, HER2 and Raf. Inhibitors of the heat shock protein Hsp90 are also included in a separate section, as this protein plays an essential role for the maturation/proper activation of cancer-related protein kinases. In the following review, the molecular details of the mode of action of these inhibitors as well as the emergence of drug resistance encountered in several cases are discussed in light of the structural, molecular and clinical studies conducted so far.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Benzamides; Benzenesulfonates; Gefitinib; HSP90 Heat-Shock Proteins; Humans; Imatinib Mesylate; Neoplasms; Niacinamide; p38 Mitogen-Activated Protein Kinases; Phenylurea Compounds; Piperazines; Protein Kinase Inhibitors; Pyridines; Pyrimidines; Quinazolines; Signal Transduction; Sirolimus; Sorafenib; Trastuzumab

The mammalian target of rapamycin (mTOR) is involved in the control of cellular growth and proliferation. Abnormal activation of signaling pathways both proximal and distal to this kinase occurs frequently in human cancer suggesting that mTOR is an attractive target for antineoplasm therapies. Rapamycin and its analogs inhibit mTOR, and have showed potent antitumor activity in vitro and in xenograft models. Several phase I and phase II studies with rapamycin-like drug have been performed demonstrating antitumor activity in different types of refractory neoplasms. The clinical development of mTOR inhibitors exemplifies the challenges in developing targeted agents. mTOR inhibitors have been well tolerated at a wide range of doses, making the selection of phase II doses based solely on toxicity criteria difficult. Assessment of pharmacodynamic effects in surrogate tumor tissues has been used to determine pharmacodynamically active doses. Lack of parallel assessment of tumor tissue effects as well as the intrinsically high interpatient variability has limited the value of these studies. A better understanding of determinants of response to mTOR inhibitors could be used for patient selection in clinical trials. In conclusion, mTOR inhibitors are promising anticancer agents. Future studies are needed to properly develop these drugs as current cancer treatment.

Topics: Animals; Antineoplastic Agents; Humans; Neoplasms; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Topics: Adult; Aged; Angiogenesis Inhibitors; Donor Selection; Female; Humans; Immunocompromised Host; Immunosuppressive Agents; Incidence; Lymphoproliferative Disorders; Male; Middle Aged; Neoplasms; Organ Transplantation; Randomized Controlled Trials as Topic; Reoperation; Risk Factors; Sarcoma, Kaposi; Sirolimus; Skin Neoplasms; Tissue Donors; TOR Serine-Threonine Kinases; Tumor Escape

Topics: Angiogenesis Inhibitors; Animals; Apoptosis; Atherosclerosis; Bone Marrow Diseases; Cell Division; Clinical Trials as Topic; Cyclosporine; Graft Rejection; Graft vs Host Disease; Humans; Immunosuppressive Agents; Kidney Diseases; Kidney Transplantation; Lymphocyte Subsets; Mice; Multicenter Studies as Topic; Muscle, Smooth, Vascular; Neoplasms; Postoperative Complications; Sirolimus; TOR Serine-Threonine Kinases; Wound Healing

Topics: Adrenal Cortex Hormones; Calcineurin Inhibitors; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Disease Susceptibility; Drug Administration Schedule; Hemolytic-Uremic Syndrome; Humans; Hypertension; Immunocompromised Host; Immunosuppressive Agents; Incidence; Kidney Diseases; Kidney Transplantation; Mycophenolic Acid; Neoplasms; Postoperative Complications; Sirolimus

Rapamycin and its derivatives (CCI-779, RAD001 and AP23576) are immunosuppressor macrolides that block mTOR (mammalian target of rapamycin) functions and yield antiproliferative activity in a variety of malignancies. Molecular characterization of upstream and downstream mTOR signaling pathways is thought to allow a better selection of rapamycin-sensitive tumours. For instance, a loss of PTEN functions results in Akt phosphorylation, cell growth and proliferation; circumstances that can be blocked using rapamycin derivatives. From recent studies, rapamycin derivatives appear to display a safe toxicity profile with skin rashes and mucositis being prominent and dose-limiting. Sporadic activity with no evidence of dose-effect relationship has been reported. Evidence suggests that rapamycin derivatives could induce G1-S cell cycle delay and eventually apoptosis depending on inner cellular characteristics of tumour cells. Surrogate molecular markers that could be used to monitor biological effects of rapamycin derivatives and narrow down biologically active doses in patients, such as the phosphorylation of P70S6K or expression of cyclin D1 and caspase 3, are currently evaluated. Since apoptosis induced by rapamycin is blocked by BCL-2, strategies aimed at detecting human tumours that express BCL-2 and other anti-apoptotic proteins might allow identification of rapamycin-resistant tumours. Finally, we discuss current and future placements of rapamycin derivatives and related translational research into novel therapeutic strategies against cancer.

Topics: Animals; Drug Delivery Systems; Humans; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Rapamycin, a valuable drug with diverse clinical applications, inhibits mTOR (mammalian target of rapamycin), which is a protein kinase that controls cell growth by regulating many cellular processes, including protein synthesis and autophagy. The sensitivity of select tumor cells to rapamycin has ignited considerable excitement over its potential as an anti-cancer therapeutic. Recent findings identified a rapamycin-insensitive function of mTOR in regulating a cell-survival pathway that is hyperactive in many cancers, particularly those with elevated PtdIns3K signaling or harboring mutations in the tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10). These new findings suggest that targeting this function of mTOR might have broader applications in cancer therapy. In this article, we re-evaluate mTOR signaling, suggesting a more central role for mTOR in cancers with defective PtdIns3K-PTEN signaling and conceptually discuss these implications in the context of drug discovery.

Topics: Animals; Antibiotics, Antineoplastic; Drosophila; Genes, Tumor Suppressor; Humans; Mutation; Neoplasms; Protein Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Up-Regulation

Rapamycin and its derivatives are promising therapeutic agents with both immunosuppressant and anti-tumor properties. These rapamycin actions are mediated through the specific inhibition of the mTOR protein kinase. mTOR serves as part of an evolutionarily conserved signaling pathway that controls the cell cycle in response to changing nutrient levels. The mTOR signaling network contains a number of tumor suppressor genes including PTEN, LKB1, TSC1, and TSC2, and a number of proto-oncogenes including PI3K, Akt, and eIF4E, and mTOR signaling is constitutively activated in many tumor types. These observations point to mTOR as an ideal target for anti-cancer agents and suggest that rapamycin is such an agent. In fact, early preclinical and clinical studies indicate that rapamycin derivatives have efficacy as anti-tumor agents both alone, and when combined with other modes of therapy. Rapamycin appears to inhibit tumor growth by halting tumor cell proliferation, inducing tumor cell apoptosis, and suppressing tumor angiogenesis. Rapamycin immunosuppressant actions result from the inhibition of T and B cell proliferation through the same mechanisms that rapamycin blocks cancer cell proliferation. Therefore, one might think that rapamycin-induced immunosuppression would be detrimental to the use of rapamycin as an anti-cancer agent. To the contrary, rapamycin decreases the frequency of tumor formation that occurs in organ transplant experiments when combined with the widely used immunosuppressant cyclosporine compared with the tumor incidence observed when cyclosporine is used alone. The available evidence indicates that with respect to tumor growth, rapamycin anti-cancer activities are dominant over rapamycin immunosuppressant effects.

Topics: Animals; Antineoplastic Agents; Cell Cycle; Drug Design; Drug Synergism; Humans; Immunosuppressive Agents; Molecular Chaperones; Neoplasms; Neovascularization, Pathologic; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Protein turnover represents the balance between protein synthesis and degradation. It can be controlled quantitatively, for instance by an activation of protein synthesis during cardiac hypertrophy or by activating protein degradation during ventricular unloading. It can also be regulated qualitatively by changing the steady state concentration of specific proteins and enzymes. The recent literature points to an emerging role for the mammalian target of rapamycin (mTOR) and for the ubiquitin-proteasome system (UPS) in this process, and both pathways interact in the regulation of cell growth and survival. We highlight the critical role played by such interaction in different cellular functions, including insulin signaling, stress response to hypoxia, adaptation to variations in workload, regulation of protein phosphatase activity, apoptosis and post-ischemic recovery. A deregulation of these pathways participates in the mechanisms of cardiac ischemia, hypertrophy and failure, and controlling their activity represents an opportunity for novel therapeutic avenues.

Topics: Animals; Cardiomyopathies; Cell Proliferation; Cell Survival; Humans; Myocytes, Cardiac; Neoplasms; Phosphorylation; Proteasome Endopeptidase Complex; Protein Biosynthesis; Proteins; Signal Transduction; Sirolimus; Ubiquitin

Hypoxia develops in the majority of solid tumors due to the inability of the existing vascular system to supply the growing tumor mass with adequate amounts of oxygen. A large body of clinical evidence suggests that intratumoral hypoxia correlates with the elevated aggressive behavior of cancer cells and their resistance to therapy, leading to poor patient prognoses. A heterodimeric transcription factor, hypoxia inducible factor-1 (HIF-1), has been shown to orchestrate a large number of molecular events required for the adaptation of tumor cells to hypoxia. Therefore, HIF-1 has become an attractive target for the development of anti-cancer drugs. Here, we highlight some of the recently developed small-molecule inhibitors of HIF-1 function. These drugs disrupt the HIF-1 signaling pathway through a variety of mechanisms, including the inhibition of HIF-1alpha protein synthesis, stabilization, nuclear translocation and HIF-1 transactivation of target genes.

Topics: Benzopyrans; Cell Hypoxia; Heterocyclic Compounds, 4 or More Rings; Humans; Hypoxia-Inducible Factor 1; Microtubules; Models, Biological; Mustard Compounds; Neoplasms; Phenylpropionates; Phosphoinositide-3 Kinase Inhibitors; Signal Transduction; Sirolimus; Topotecan; Tubulin Modulators

The mammalian target of rapamycin (mTOR) is a kinase responsible for mitogen-induced cell proliferation/survival signaling. Its activation in response to mitogens leads to a cell-cycle progression from G1 to S phase. mTOR controls the activation of ribosomal protein translation and the initiation of cap-dependent translation. A role of mTOR signaling pathway dysregulation in tumourigenesis is postulated. mTOR and pathways upstream of this kinase were found to be frequently upregulated in neoplastic diseases. Therefore, it is also an attractive target for antitumour therapy. Several mTOR inhibitors were developed, including rapamycin and its analogues: CCI-779, RAD001 and AP23573. After promising phase I studies, their potential clinical significance is currently under evaluation in several phase II-III trials on patients with solid tumours and some hematological malignancies.

Topics: Antibiotics, Antineoplastic; Humans; Models, Biological; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Immunosuppressive drug therapy has been identified as one etiological factor in the increased incidence of and deaths from malignancies in renal transplant recipients. In animal models, calcineurin inhibitors have a positive growth effect, whereas target-of-rapamycin (TOR) inhibitors have a negative growth effect on malignant cells.. A multivariate analysis of posttransplant malignancies in 33,249 deceased donor primary solitary renal recipients reported by 264 kidney transplant programs to the Organ Procurement and Transplantation Network database from July 1, 1996 to December 31, 2001 was performed. Data were censored at 963 days to allow comparable follow-up time among drug treatment groups. The incidence and relative risks of any de novo malignancy (skin and solid) and for non-skin solid malignancies in patients receiving TOR inhibitors compared to patients receiving calcineurin inhibitors were the primary endpoints.. The incidence rates of patients with any de novo posttransplant malignancy were 0.60% with sirolimus/everolimus alone, 0.60% with sirolimus/everolimus + cyclosporine/tacrolimus, and 1.81% with cyclosporine/tacrolimus (P<0.0001); the rates with a de novo solid tumor were 0%, 0.47%, and 1.00%, respectively. In the Cox regression model the relative risk associated with sirolimus/everolimus immunosuppression for any de novo cancer was 0.39 (95% CI: 0.24-0.64; P=0.0002) and for de novo solid cancer was 0.44 (0.24-0.82; P=0.0092). Other significant risk factors were male sex, adult age group, white race, and history of a malignancy.. Maintenance immunosuppression with the TOR inhibitor drugs, sirolimus and everolimus, is associated with a significantly reduced risk of developing any posttransplant de novo malignancy and non-skin solid malignancy.

Topics: Everolimus; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Incidence; Kidney Transplantation; Neoplasms; Protein Kinases; Risk Assessment; Sirolimus; TOR Serine-Threonine Kinases

As newer immunosuppressive regimens have steadily reduced the incidence of acute rejection and have extended the life expectancy of allograft recipients, posttransplant malignancy has become an important cause of mortality. In fact, it is expected that cancer will surpass cardiovascular complications as the leading cause of death in transplant patients within the next 2 decades. An understanding of the underlying pathobiology and how to minimize cancer risks in transplant recipients are essential. The etiology of posttransplant malignancy is believed to be multifactorial and likely involves impaired immunosurveillance of neoplastic cells as well as depressed antiviral immune activity with a number of common posttransplant malignancies being viral-related. Although calcineurin inhibitors and azathioprine have been linked with posttransplant malignancies, newer agents such as mycophenolate mofetil and sirolimus have not and indeed may have antitumor properties. Long-term data are needed to determine if the use of these agents will ultimately lower the mortality due to malignancy for transplant recipients.

Topics: Azathioprine; Calcineurin Inhibitors; Carcinoma, Hepatocellular; Cyclosporine; Hepatitis, Viral, Human; Humans; Immunosuppressive Agents; Incidence; Kidney Transplantation; Lymphoproliferative Disorders; Mycophenolic Acid; Neoplasms; Sirolimus; Skin Neoplasms; Tacrolimus; Transplantation Immunology; Transplantation, Homologous

A considerable amount of data indicates that transplanted patients are at increased risk for de novo and recurrent cancer. Treatment of this population is difficult. It remains unclear if the immunosuppressive therapy should be continued, tapered or even stopped or if immunosuppressive drugs with antiproliferative properties have beneficial effects in this situation. In various models, mTOR-inhibitors were shown to have immunosuppressive and anti-tumor effects. Here, we have reviewed the current literature trying to clarify if mTOR-inhibition brings advantages for the transplanted patients suffering from tumors.

Topics: Humans; Immunosuppressive Agents; Neoplasms; Organ Transplantation; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases; Transplantation Immunology

Topics: Antibiotics, Antineoplastic; Apoptosis; Cell Cycle; Humans; Neoplasms; Neovascularization, Pathologic; Phosphatidylinositol 3-Kinases; Protein Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Rapamycin is a clinically approved immunosuppressive agent that has recently shown promising antitumor activities in human patients. In contrast to many conventional chemotherapeutic agents, rapamycin displays a remarkably high level of selectivity for certain types of tumors. The pharmacological activities of rapamycin are attributable to the functional inhibition of a single target protein, termed the mammalian target of rapamycin (mTOR). Because mTOR is widely expressed in both normal and transformed cells, variations in mTOR expression levels are likely not a primary determinant of tumor sensitivity to rapamycin. However, recent studies highlighted an intriguing link between cancer cell sensitivity to rapamycin and deregulated signaling through the phosphoinositide (PI) 3-kinase pathway. These findings have prompted a search for cancer-related responses that are jointly regulated by the PI 3-kinase signaling cascade and mTOR. The oxygen-regulated transcription factor, hypoxia-induced factor (HIF)-1, has emerged as a candidate target for both of these two highly interactive signaling proteins. Here we review evidence that mTOR functions as a positive regulator of HIF-1-dependent responses to hypoxic stress in human cancer cells.

Topics: Animals; Antibiotics, Antineoplastic; Cell Hypoxia; DNA-Binding Proteins; Humans; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Neoplasms; Nuclear Proteins; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Transcription, Genetic; Tumor Cells, Cultured

The target of rapamycin, mTOR, acts as a sensor for mitogenic stimuli, such as insulin-like growth factors and cellular nutritional status, regulating cellular growth and division. As many tumors are driven by autocrine or paracrine growth through the type-I insulin-like growth factor receptor, mTOR is potentially an attractive target for molecular-targeted treatment. Further, a rationale for anticipating tumor-selective activity based on transforming events frequently identified in malignant disease is becoming established.

Topics: Animals; Antibiotics, Antineoplastic; Apoptosis; Child; Clinical Trials as Topic; Humans; Insulin-Like Growth Factor I; Neoplasms; Protein Kinases; Receptor, Insulin; Rhabdomyosarcoma, Alveolar; Sirolimus; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

Current efforts in anticancer drug development are targeting key factors in cell-cycle regulation. Mammalian target of rapamycin (mTOR) is one such protein kinase that facilitates cell growth by stimulating the cell to traverse the G1 to S phase of the cell cycle. Rapamycin is the first defined inhibitor of mTOR, and the demonstration of its antitumor activity has led to great interest in this pathway as an antitumor mechanism. Analogues with better pharmacologic properties have been developed and have entered clinical trials. Human cell lines of renal cell cancer, among several other tumors, are sensitive to growth inhibition via this pathway. Ongoing clinical trials are evaluating renal cell cancer and other malignancies using therapy with mTOR inhibitors. These agents are more likely to induce growth inhibition rather than tumor regression.

Topics: Antibiotics, Antineoplastic; Cell Division; Cell Line, Tumor; Clinical Trials as Topic; Drug Evaluation, Preclinical; Humans; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Apoptotic defects occur in oncogenesis and contribute to drug resistance. We have shown that Bcl-2, Akt, and the translational regulator eIF4E cooperate with Myc during lymphomagenesis and are potent inducers of drug resistance. Interestingly, lymphomas expressing Akt, but not those expressing Bcl-2 are sensitized to chemotherapy-induced apoptosis by the mTOR inhibitor rapamycin, an effect that is countered by eIF4E. These results provide in vivo validation for a strategy to reverse drug resistance in human cancers and highlight the potential role of translational deregulation in oncogenesis and resistance. They also illustrate the importance of tailoring cancer therapy based on tumor genotype.

Topics: Animals; Antibiotics, Antineoplastic; Apoptosis; Cell Transformation, Neoplastic; Drug Resistance, Neoplasm; Eukaryotic Initiation Factor-4E; Gene Expression Regulation, Neoplastic; Humans; Neoplasms; Protein Kinases; Proto-Oncogene Proteins c-akt; Sirolimus; TOR Serine-Threonine Kinases

mTOR is a downstream mediator in the PI3K/Akt signalling pathway, which plays a critical role in regulating basic cellular functions. These include cell proliferation, survival, mobility and angiogenesis. Rapamycin and its analogues (CCI-779, RAD001 and AP23573) have specific antagonistic action on the function of mTOR. This leads to inhibition of the downstream signalling elements and results in the cell cycle arrest in the G1 phase. This group of drugs may have a place in Oncology for the treatment of cancers, which occur as a result of increased activity of the PI3 kinase/Akt/m-TOR pathway. The basic structure of the pathway was reviewed in this article, together with results of the clinical studies targeting mTOR for cancer therapy. This is an exciting area for development and poses many challenges to researchers.

Topics: Animals; Antibiotics, Antineoplastic; Cell Cycle; Clinical Trials as Topic; Humans; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Topics: 3-Phosphoinositide-Dependent Protein Kinases; Antibiotics, Antineoplastic; Apoptosis; Cell Proliferation; Cell Survival; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus

The protein kinase Akt is activated in a wide variety of cancers, and this activation results in enhanced resistance to apoptosis through multiple mechanisms. This article reviews the control of Akt activation by the opposing actions of the oncogene phosphoinositide 3-kinase (PI3-K) and the tumor suppressor phosphatase and tensin homolog deleted on chromosome 10. The activation of Akt by transforming mutations, such as the amplification of HER-2/neu in breast cancer and the formation of the BCR/ABL fusion gene in chronic myelogenous leukemia, seems to be essential for the transforming activity of these oncogenes. We discuss several of the proposed mechanisms for the antiapoptotic effect of activated Akt, including the inhibition of the proapoptotic protein Bad, downregulation of death receptors, and enhancement of the glycolytic rate. Increased glycolysis is seen in many malignancies and forms the basis for the increasing use of positron emission tomography imaging for diagnosis and staging. Finally, we discuss rapamycin and its analogs, which are now in trials as antineoplastic therapy; these agents show particular promise in tumors in which Akt has been activated.

Topics: Apoptosis; Gene Expression Regulation, Enzymologic; Glycolysis; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoric Monoester Hydrolases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Signal Transduction; Sirolimus; Tumor Suppressor Proteins

Wyeth (formerly American Home Products) is developing temsirolimus [Cell cycle inhibitor-779, CCI 779], an ester analogue of sirolimus, for the treatment of cancer, multiple sclerosis and rheumatoid arthritis. Temsirolimus binds to the cytosolic protein, FKBP, which subsequently inhibits mTOR (mammalian target of rapamycin). Inhibition of mTOR blocks a number of signal transduction pathways that suppress translation of several key proteins regulating the cell cycle. These effects lead to a cell cycle block at the G1 phase. In animal models of human cancers, temsirolimus inhibited the growth of a diverse range of cancer types even when an intermittent dosing schedule was used. The compound also appears to have potential for the blockade of inflammatory responses associated with autoimmune and rheumatic diseases by inhibiting T-cell proliferation. On 11 March 2002, American Home Products changed its name and the name of its subsidiary Wyeth-Ayerst to Wyeth. During the first half of 2004, Wyeth initiated ongoing recruitment into a US phase III trial comparing orally administered temsirolimus plus letrozole versus letrozole alone as first-line treatment among approximately 1200 postmenopausal women with advanced breast cancer. The multicentre, randomised, double-blind, placebo-controlled trial is estimated to last 34 months. All subjects will have the option of participating in the long-term follow-up phase of the trial that involves follow-up every 3 months until disease progression; the primary endpoint is overall progression-free survival. In August 2004, the US FDA granted temsirolimus fast-track status for the first-line treatment of poor-prognosis patients with advanced renal cell carcinoma. Previously in March 2002, temsirolimus received fast-track status from the FDA for the treatment of renal cell carcinoma in patients who failed to respond to interleukin-2 treatment. Wyeth intends to file a NDA for temsirolimus for this indication by 2006. Researchers from Wyeth presented the findings from a preclinical study of temsirolimus at the 67th Annual Scientific Meeting of the American College of Rheumatology and the 38th Annual Meeting Association of Rheumatology Health Professionals (ACR/ARHP-2003) [Orlando, FL, USA; October 2003]. The aim of this study was to determine the effect of temsirolimus on lymphocyte proliferation and cytokine production. Since lymphocytes and cytokines are significantly involved in the pathogenesis of rheumatoid arthritis, tems

Topics: Animals; Antibiotics, Antineoplastic; Breast Neoplasms; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Female; Humans; Immunosuppressive Agents; Neoplasms; Rheumatic Diseases; Sirolimus

Highly specific signal transduction inhibitors are being developed as anti-cancer agents against an array of molecular targets, with the promise of increased selectivity and lower toxicity than classic cytotoxic chemotherapy agents. Rapamycin and its analogues are a promising class of novel therapeutics that specifically inhibit signaling from the serine-threonine kinase, mammalian target of rapamycin (mTOR). mTOR is a key intermediary in multiple mitogenic signaling pathways and plays a central role in modulating proliferation and angiogenesis in normal tissues and neoplastic processes. Rapamycin potently inhibits T-cell proliferation, and is approved for clinical use as an immuno-suppressant following kidney transplantation. Hyperactivation of mTOR signaling has been implicated in tumorigenesis, and promising pre-clinical studies in several tumor types suggest that the anti-proliferative and anti-angiogenic properties of rapamycin may be useful in cancer therapy. These studies have led to several clinical trials evaluating the safety and efficacy of rapamycin analogs in cancer therapy. The goal of this article is to review the mechanism of action of rapamycin as an anti-cancer agent, and to review the clinical experience with rapamycin and rapamycin analogs as immunosuppressive and anti-neoplastic therapeutic agents.

Topics: Animals; Antineoplastic Agents; Humans; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Target of rapamycin (TOR) functions within the cell as a transducer of information from various sources, including growth factors, energy sensors, and hypoxia sensors, as well as components of the cell regulating growth and division. Blocking TOR function mimics amino acid, and to some extent, growth factor deprivation and has a cytostatic effect on proliferating cells in vivo. Inhibition of TOR in vivo, utilising its namesake rapamycin, leads to immunosuppression. This property has been exploited successfully with the use of rapamycin and its derivatives as a therapeutic agent in the prevention of organ rejection after transplantation with relatively mild side effects when compared to other immunosuppressive agents. The cytostatic effect of TOR on vascular smooth muscle cell proliferation has also recently been exploited in the therapeutic application of rapamycin to drug eluting stents for angioplasty. These stents significantly reduce the amount of arterial reblockage that results from proliferating vascular smooth muscle cells. In cancer, the effect of blocking TOR function on tumour growth and disease progression is currently of major interest and is the basis for a number of ongoing clinical trials. However, different cell types and tumours respond differently to TOR inhibition, and TOR is clearly not cytostatic for all types of cancer cells in vitro or in vivo. As the molecular details of how TOR functions and the targets of TOR activity are further elucidated, tumour and tissue specific functions are being identified that implicate TOR in angiogenesis, apoptosis, and the reversal of some forms of cellular transformation. This review will describe our current understanding of TOR function, describe the current strategies for employing TOR inhibitors in clinical and preclinical development, and outline future strategies for appropriate targets of TOR inhibitors in the treatment of disease.

Topics: Antineoplastic Agents; Apoptosis; Arterial Occlusive Diseases; Cell Division; Clinical Trials as Topic; Energy Metabolism; Gene Expression Regulation; Growth Substances; Heart Transplantation; Humans; Immunosuppressive Agents; Models, Biological; Muscle, Smooth, Vascular; Neoplasm Proteins; Neoplasms; Neovascularization, Pathologic; Postoperative Complications; Protein Kinase Inhibitors; Protein Kinases; Protein Structure, Tertiary; Signal Transduction; Sirolimus; Stents; TOR Serine-Threonine Kinases; Wound Healing

Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a phosphatase that removes phosphates primarily from lipids. It has also been called mutated in multiple advanced cancers 1 and transforming growth factor-beta regulated epithelial cell-enriched phosphatase 1. The best described substrate of PTEN is phosphatidyliniositol (3,4,5)-tris-phosphate [PtdIns(3,4,5)P3]. PTEN removes the phosphate in PtdIns(3,4,5)P(3) to generate PtdIns(4,5)P(2). PTEN serves to counter-balance the effects of phosphoinositide 3' kinase, which normally adds a phosphate to PtdIns(4,5)P(2) to generate PtdIns(3,4,5)P(3). PtdIns(3,4,5)P(3) recruits kinases such as phosphoinositide-dependent kinase 1, which in turn phosphorylate Akt, which phosphorylates other downstream proteins involved in regulation of apoptosis and cell-cycle progression. PTEN removal of the phosphate from PtdIns(3,4,5)P(3) inhibits this pathway by preventing localisation of proteins with pleckstrin homology domains to the cell membrane. Alterations of the PTEN gene are associated with cancer and other diseases. Novel therapeutic approaches have been developed to counteract the deletion/mutation of PTEN in human cancer. This review will discuss the role of PTEN in signal transduction and cancer as well as pharmacological approaches to combat PTEN loss in human cancer.

Topics: Animals; Apoptosis; Biomarkers, Tumor; Cell Cycle; Cell Nucleus; Female; Genes, Tumor Suppressor; Hamartoma Syndrome, Multiple; Humans; Lung Diseases; Male; Mice; Models, Biological; Neoplasm Proteins; Neoplasms; Phosphatidylinositol Phosphates; Phospholipids; Phosphoproteins; Phosphoric Monoester Hydrolases; Phosphorylation; Protein Processing, Post-Translational; Protein Structure, Tertiary; Protein-Tyrosine Kinases; PTEN Phosphohydrolase; Receptor, Insulin; Signal Transduction; Sirolimus; Tumor Suppressor Proteins

The molecular target of rapamycin, which is a member of the phosphoinositide 3-kinase related kinase family and a central modulator of cell growth, is a unique and prime strategic target for anticancer therapeutic development.. The molecular target of rapamycin plays a critical role in transducing proliferative signals mediated through the phosphatidylinositol 3 kinase and protein kinase B signaling pathways, principally by activating downstream protein kinases that are required for both ribosomal biosynthesis and translation of mRNAs of proteins that are essential for G1 to S phase traverse. By targeting the molecular target of rapamycin with high potency and specificity, the immunosuppressant and antiproliferative agent rapamycin inhibits signals required for cell cycle progression, cell growth, and proliferation. Both rapamycin and several rapamycin analogs with more favorable pharmaceutical properties have demonstrated impressive growth inhibitory effects against a broad range of human cancers in both preclinical and early clinical evaluations.. This review discusses recent findings regarding the principal mechanisms of action of the rapamycins, the potential utility of these agents as anticancer therapeutics, clinical results to date, and developmental challenges that lie ahead.

Topics: Antibiotics, Antineoplastic; Clinical Trials, Phase I as Topic; Humans; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Targeted molecular therapeutics are tailored toward the genetic abnormalities that cause tumor progression. Modulation of certain signaling pathways that are aberrant in cancer cells has the potential to provide an effective, nontoxic approach to therapy in a broad range of cancers. Agents targeting BCR-ABL (imatinib mesylate [formerly known as STI-571], Gleevec; Novartis Pharmaceuticals Corp, East Hanover, NJ), retinoid receptor fusion proteins (all-trans retinoic acid), ErbB-2 or HER2/neu (trastuzumab, Herceptin; Genentech, Inc, South San Francisco, CA), epidermal growth factor receptor (IMC-C225 and ZD1839), and the phosphatidylinositol 3-kinase pathway (CCI-779) have all induced remarkable, nontoxic responses in a subset of patients with cancer and abnormalities in the corresponding signal transduction cascades. To achieve successful individualized therapy, the specific components within the aberrant signaling pathways that are driving the pathophysiology of the tumors must be identified in each patient. Molecular diagnostics can identify patients in whom the target is aberrant; linking molecular diagnostics with effective molecular therapeutics will be necessary to translate these concepts into approaches that will alter the outcome for patients with cancer. In addition, intermediary markers and/or molecular imaging techniques must be used to identify the biologically relevant dose that is sufficient to inhibit the target of interest. This review focuses on the P13K pathway, and novel molecules targeting this pathway, to illustrate the questions and challenges underlying the implementation of molecular therapeutics in breast and ovarian cancer.

Topics: Animals; Antineoplastic Agents; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphoric Monoester Hydrolases; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; PTEN Phosphohydrolase; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Suppressor Proteins

Signaling networks that promote cell growth are frequently dysregulated in cancer. One regulatory network, which converges on effectors such as 4EBP1 and S6K1, leads to growth by promoting protein synthesis. Here, we discuss how this network is regulated by both extracellular signals, such as growth factors, and intracellular signals, such as nutrients. We discuss how mutations amplifying either type of signal can lead to tumor formation. In particular, we focus on the recent discovery that a tumor suppressor complex whose function is lost in tuberous sclerosis patients regulates the nutrient signal carried by the critical signaling protein TOR to the effectors 4EBP1 and S6K1. Finally, we describe how the small molecule rapamycin, which inhibits TOR and thereby the activation of these effectors, could be useful to treat tumors that have become dependent upon this pathway for growth.

Topics: Adaptor Proteins, Signal Transducing; Animals; Carrier Proteins; Cell Cycle Proteins; Cell Division; Enzyme Inhibitors; Growth Substances; Humans; Models, Biological; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus

Wyeth Research (formerly Wyeth-Ayerst Research) is developing the sirolimus (rapamycin) analog CCI-779 as a potential treatment for various cancers [320924]. By November 2001, phase III trials had been initiated [428972], [429576]. In October 2001, Raymond James predicted filing in 2003, with a potential launch in 2005 [426718]. In March 2002, CCI-779, was designated for fast-track development by the FDA for the treatment of renal cell carcinoma after failure of initial therapy [442535]; at this time phase III trials for renal cell carcinoma and phase II trials for various solid tumors were ongoing [444030]. In March 2002, Wyeth revealed that filing was anticipated for 2004/2005 [443491]. In June and August 2001, Lehman Brothers predicted sales of US $40 million ($20 million in the US) in 2003, rising to US $75 million ($38 million in the US) in 2004 [418901], [420809]. In October 2001, analysts at Raymond James expected potential sales of the product at US $250 million [426718]. In May 2002, a patent (WO-00240000) was published claiming CCI-779 to be useful for the treatment of cancers of various origins, including renal, breast, cervical, uterine, head and neck, lung, prostate, pancreatic, ovarian, colon, lymphoma and melanoma.

Topics: Animals; Antibiotics, Antineoplastic; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Contraindications; Humans; Neoplasms; Protein Synthesis Inhibitors; Sirolimus

Rapamycin and CCI-779 have significant in vitro and in vivo anti-proliferative activity against a broad range of human tumor cell lines, justifying the clinical evaluation of this class of agent in cancer patients. Preliminary results from phase I studies of CCI-779 suggest that the agent is well tolerated and has anti-tumor activity. The challenge to investigators is to efficiently determine what role this class of agent will play in the treatment of cancer patients.

Topics: Adaptor Proteins, Signal Transducing; Animals; Antineoplastic Agents; Carrier Proteins; Cell Cycle Proteins; Cell Division; Clinical Trials as Topic; Cyclic AMP-Dependent Protein Kinases; Drug Design; Enzyme Inhibitors; Eukaryotic Initiation Factors; Everolimus; Humans; Immunosuppressive Agents; Mice; Neoplasm Proteins; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; Protein Processing, Post-Translational; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

Rapamycin and its derivatives, CCI-779 and RAD-001, inhibit the mammalian target of rapamycin (mTOR), downregulating translation of specific mRNAs required for cell cycle progression from G1 to S phase. Preclinically, mTOR inhibitors potently suppress growth and proliferation of numerous tumor cell lines in culture or when grown in mice as xenografts. CCI-779 and RAD-001 are being developed as antitumor drugs and are undergoing clinical trials. Clinically, CCI-779 has shown evidence of antitumor activity but induced relatively mild side effects in patients. Here we discuss potential antitumor mechanisms and resistance mechanisms of mTOR inhibitors, and summarize the current status of these compounds as novel antitumor agents.

Topics: Antineoplastic Agents; Cell Division; Clinical Trials, Phase I as Topic; Drug Resistance, Neoplasm; Everolimus; Humans; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Tumor Cells, Cultured

The macrocyclic lactone rapamycin has an established place as an immune suppressive agent in organ transplantation. However, more recently it has been recognized as an inhibitor of pathways that may be activated during malignant transformation and tumor progression. Thus, increasing interest is being directed to this class of antibiotic as potential antitumor agents. Here we summarize the history, mechanism of action, and mechanisms of resistance to rapamycin.

Topics: Animals; Antibiotics, Antineoplastic; Drug Resistance, Neoplasm; Neoplasms; Sirolimus

Resistance to treatment with inhibitors of mammalian target of rapamycin (mTOR) is partially mediated by activation of epidermal growth factor receptor (EGFR). We conducted a phase I study to determine the recommended phase II dose (RP2D) and dose-limiting toxicities (DLT) of temsirolimus (mTOR inhibitor) combined with erlotinib (EGFR inhibitor) in patients with refractory solid tumors.. Standard "3 + 3" design was used for dose escalation. An expansion cohort at RP2D included only patients with squamous histology or mutations relevant to PI3K or EGFR pathway activation. Patients started daily erlotinib 7 days prior to starting temsirolimus on cycle 1. Intravenous temsirolimus was then administered weekly. Starting dose levels were 15 mg for temsirolimus and 100 mg for erlotinib.. Forty-four patients received treatment on this study (28 in dose escalation and 16 in the expansion cohort). The RP2D was temsirolimus 25 mg IV weekly and erlotinib 100 mg orally daily. Two patients experienced DLTs (G3 dehydration and G4 renal failure). The most common drug-related adverse events (all grades) were rash, mucositis/stomatitis, diarrhea, nausea and fatigue. No complete or partial responses were observed. The median duration on this study was 69 days (range 3-770) for escalation and 88 days (range 25-243) for expansion cohorts. Among 11 response-evaluable patients in the expansion cohort, 9 (82%) had stable disease and 2 (18%) had progressive disease.. The combination of temsirolimus and erlotinib at the RP2D was well tolerated, and the regimen resulted in prolonged disease stabilization in selected patients (NCT00770263).

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Cohort Studies; Disease Progression; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; ErbB Receptors; Erlotinib Hydrochloride; Female; Humans; Male; Middle Aged; Mutation; Neoplasms; Phosphatidylinositol 3-Kinase; Sirolimus; Treatment Outcome

To determine the maximum tolerated dose, toxicities, and response of sirolimus combined with oral metronomic therapy in pediatric patients with recurrent and refractory solid and brain tumors.. Patients younger than 30 years of age with recurrent, refractory, or high-risk solid and brain tumors were eligible. Patients received six-week cycles of sirolimus with twice daily celecoxib, and alternating etoposide and cyclophosphamide every three weeks, with Bayesian dose escalation over four dose levels (NCT01331135).. Eighteen patients were enrolled: four on dose level (DL) 1, four on DL2, eight on DL3, and two on DL4. Diagnoses included solid tumors (Ewing sarcoma, osteosarcoma, malignant peripheral nerve sheath tumor, rhabdoid tumor, retinoblastoma) and brain tumors (glioblastoma multiforme [GBM], diffuse intrinsic pontine glioma, high-grade glioma [HGG], medulloblastoma, ependymoma, anaplastic astrocytoma, low-grade infiltrative astrocytoma, primitive neuroectodermal tumor, nongerminomatous germ cell tumor]. One dose-limiting toxicity (DLT; grade 4 neutropenia) was observed on DL2, two DLTs (grade 3 abdominal pain and grade 3 mucositis) on DL3, and two DLTs (grade 3 dehydration and grade 3 mucositis) on DL4. The recommended phase II dose of sirolimus was 2 mg/m. The combination of sirolimus with metronomic chemotherapy is well tolerated in children. A phase II trial of this combination is ongoing.

Topics: Administration, Metronomic; Adolescent; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Celecoxib; Child; Child, Preschool; Cyclophosphamide; Dose-Response Relationship, Drug; Etoposide; Female; Humans; Male; Maximum Tolerated Dose; Neoplasms; Sirolimus; Young Adult

Purpose SM-88 (D,L-alpha-metyrosine; racemetyrosine) is a novel anti-cancer agent, used with melanin, phenytoin, and sirolimus (SMK Therapy). This pilot first-in-human study characterized the safety, tolerability, and efficacy of SMK Therapy in subjects with advanced metastatic cancer. Methods All subjects (n = 30) received SMK Therapy for an initial 6 week Cycle (5 days on, 2 off per week) and continued if well tolerated. Safety signals, clinical response, overall survival, progression free survival (PFS), and quality of life changes were assessed. Results The most common drug related adverse events were hyperpigmentation and rash. All drug related adverse events were mild to moderate in intensity. Following treatment with SMK Therapy, 4 subjects achieved complete response, 6 partial response, and 17 stable disease according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 (total clinical benefit 90%). Responses were observed within 6 weeks, and continued to improve, with 3 complete and 3 partial responders achieving best response after at least 3.2 months. Durable stable disease was observed, lasting a median duration of 11 months (range 1-31 months). Median overall survival for all subjects was 29.8 months, and median PFS was 13 months. Following 6 weeks of treatment, most (83.3%) subjects showed an improvement in Eastern Cooperative Oncology Group (ECOG) score and an improvement in the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ 30) global health status (baseline 61.2 ± 25.0; end of Cycle 1 80.7 ± 14.7; n = 29; p < 0.001). Conclusions The results of this study support continued development of SM-88.

Topics: Aged; alpha-Methyltyrosine; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Exanthema; Female; Humans; Hyperpigmentation; Male; Melanins; Middle Aged; Neoplasms; Phenytoin; Pilot Projects; Quality of Life; Sirolimus; Survival Analysis

Sirolimus is a mammalian target of rapamycin (mTOR) inhibitor. Metformin may potentiate mTOR inhibition by sirolimus while mitigating its adverse effects. We conducted a pilot study to test this hypothesis.. Patients with advanced solid tumor were treated with sirolimus for 7 days followed by randomization to either sirolimus with metformin (Arm A) or sirolimus (Arm B) until day 21. From day 22 onwards, all patients received sirolimus and metformin. The primary aim was to compare the change in phospho-p70S6K (pp70S6K) in peripheral blood mononuclear cells (PBMC) from day 8 to day 22 using a two-sample t test. Secondary aims were objective response rate, toxicity, and other serum pharmacodynamic biomarkers (e.g., fasting glucose, triglycerides, insulin, C-peptide, IGF-1, IGF-1R, IGF-BP, and leptin).. 24 patients were enrolled, with 18 evaluable for the primary endpoint. There was no significant difference in mean change in pp70S6K in arm A vs. arm B (- 0.12 vs. - 0.16; P = 0.64). Similarly, there were no significant differences in other serum pharmacodynamic biomarkers. There were no partial responses. There were no dose-limiting or unexpected toxicities.. Adding metformin to sirolimus, although well tolerated, was not associated with significant changes in pp70S6K in PBMC or other serum pharmacodynamic biomarkers.. Combining metformin with sirolimus did not improve mTOR inhibition.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Drug Synergism; Female; Humans; Leukocytes, Mononuclear; Male; Metformin; Middle Aged; Neoplasms; Phosphorylation; Pilot Projects; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; TOR Serine-Threonine Kinases; Young Adult

Background Combinations of molecularly targeted agents may provide optimal anti-tumor activity and improve clinical outcomes for patients with advanced cancers. Selumetinib (AZD6244, ARRY-142886) is an oral, potent and highly selective, allosteric inhibitor of MEK1/2, a component of the RAS/RAF/MEK/ERK pathway which is constitutively activated in many cancers. We investigated the safety, tolerability, and pharmacokinetics (PK) of selumetinib in combination with molecularly targeted drugs erlotinib or temsirolimus in patients with advanced solid tumors. Methods Two-part study: dose escalation, to determine the maximum tolerated dose (MTD) of selumetinib in combination with erlotinib 100 mg once daily (QD) or temsirolimus 25 mg once weekly, followed by dose expansion at the respective combination MTDs to further investigate safety and anti-tumor effects. Results 48 patients received selumetinib plus erlotinib and 32 patients received selumetinib plus temsirolimus. The MTD with erlotinib 100 mg QD was selumetinib 100 mg QD, with diarrhea being dose limiting. The most common all grade adverse events (AEs): diarrhea, rash, nausea, and fatigue. Four (8.3%) patients had ≥12 weeks stable disease. The MTD with temsirolimus 25 mg once weekly was selumetinib 50 mg twice daily (BID), with mucositis and neutropenia being dose limiting. The most commonly reported AEs: nausea, fatigue, diarrhea, and mucositis. Ten (31.3%) patients had ≥12 weeks stable disease. The combination PK profiles were comparable to previously observed monotherapy profiles. Conclusions MTDs were established for selumetinib in combination with erlotinib or temsirolimus. Overlapping toxicities prevented the escalation of selumetinib to its recommended phase II monotherapy dose of 75 mg BID.. ClinicalTrials.gov NCT00600496; registered 8 July 2009.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzimidazoles; Dose-Response Relationship, Drug; Erlotinib Hydrochloride; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Sirolimus

Ridaforolimus is a mammalian target of rapamycin inhibitor that has activity in solid tumors. Paclitaxel and carboplatin have broad antineoplastic activity in many cancers. This phase I trial was conducted to determine the safety profile, maximal tolerated dose, and recommended phase II dose and schedule of oral ridaforolimus combined with paclitaxel and carboplatin in patients with solid tumor cancers.. Thirty-one patients were consented, 28 patients were screened, and 24 patients met eligibility requirements and received treatment. Two patients were replaced for events unrelated to drug-related toxicity, resulting in 22 DLT-evaluable patients. Two grade 4 DLTs due to neutropenia were observed at dose level 1. The next cohort was changed to a predefined alternate dosing schedule (days 1-5 and 8-12). DLTs were neutropenia, sepsis, mucositis, and thrombocytopenia. The most common adverse events were neutropenia, anemia, thrombocytopenia, fatigue, alopecia, nausea, pain, and leukopenia. Twenty-four patients received a median of 4 cycles (range, 1-12). Evaluable patients for response (n = 18) demonstrated a median tumor measurement decrease of 25%. The best response in these 18 patients included 9 patients with partial response (50%), 6 with stable disease (33%), and 3 with progressive disease (17%). Thirteen of these patients received treatment for 4 or more cycles.. ClinicalTrials.gov Identifier: NCT01256268 (trial registration date: December 1, 2010).

Topics: Administration, Oral; Adult; Aged; Anemia; Antineoplastic Combined Chemotherapy Protocols; Carboplatin; Dose-Response Relationship, Drug; Drug Administration Schedule; Fatigue; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Neutropenia; Paclitaxel; Research Design; Sirolimus; Thrombocytopenia

Preclinical studies suggest synergistic antitumour effects of mammalian target of rapamycin (mTOR) inhibitor such as temsirolimus combined with anti-EGFR monoclonal antibody such as cetuximab.. Combination of T + C showed significant but manageable toxicities. Due to modest clinical activity, further evaluation is not recommended. Molecular selection could potentially increase the objective response rate and should be implemented during drug development.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Cetuximab; Disease-Free Survival; Dose-Response Relationship, Drug; Female; Humans; Male; Middle Aged; Neoplasms; Sirolimus; Survival Analysis

To determine the maximum tolerated dose (MTD), toxicities, and pharmacodynamics effects of sirolimus combined with oral metronomic topotecan and cyclophosphamide in a pediatric population.. Patients who were 1 to 30 years of age with relapsed/refractory solid tumors (including CNS) were eligible. Patients received daily oral sirolimus and cyclophosphamide (25-50 mg/m2/dose) on days 1-21 and oral topotecan (0.8 mg/m2/dose) on days 1-14 in 28-day cycles. Sirolimus steady-state plasma trough concentrations of 3-7.9 ng/mL and 8-12.0 ng/mL were evaluated, with dose escalation based on a 3+3 phase 1 design. Biomarkers of angiogenesis were also evaluated.. Twenty-one patients were treated (median age 18 years; range 9-30). Dose-limiting toxicities included myelosuppression, ALT elevation, stomatitis, and hypertriglyceridemia. The MTD was sirolimus with trough goal of 8-12.0 ng/mL; cyclophosphamide 25 mg/m2/dose; and topotecan 0.8 mg/m2/dose. No objective responses were observed. Four patients had prolonged stable disease > 4 cycles (range 4-12). Correlative biomarker analyses demonstrated reductions in thrombospondin-1 (p=0.043) and soluble vascular endothelial growth factor receptor-2 plasma concentrations at 21 days compared to baseline.. The combination of oral sirolimus, topotecan, and cyclophosphamide was well tolerated and biomarker studies demonstrated modulation of angiogenic pathways with this regimen.

Topics: Adolescent; Adult; Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Child; Cyclophosphamide; Female; Humans; Male; Neoplasm Recurrence, Local; Neoplasms; Sirolimus; Topotecan; Young Adult

Temsirolimus is an inhibitor of the mammalian target of rapamycin (mTOR). Pharmacokinetic (PK) characterization of temsirolimus in children is limited and there is no paediatric temsirolimus population PK model available. The objective of this study was to simultaneously characterize the PK of temsirolimus and its metabolite sirolimus in paediatric patients with recurrent solid or central nervous system tumours and to develop a population PK model.. The PK data for temsirolimus and sirolimus were collected as a part of a Children's Oncology Group phase I clinical trial in paediatric patients with recurrent solid tumours. Serial blood concentrations obtained from 19 patients participating in the PK portion of the study were used for the analysis. Population PK analysis was performed by nonlinear mixed effect modelling using NONMEM.. A three-compartment model with zero-order infusion was found to best describe temsirolimus PK. Allometrically scaled body weight was included in the model to account for body size differences. Temsirolimus dose was identified as a significant covariate on clearance. A sirolimus metabolite formation model was developed and integrated with the temsirolimus model. A two-compartment structure model adequately described the sirolimus data.. This study is the first to describe a population PK model of temsirolimus combined with sirolimus formation and disposition in paediatric patients. The developed model will facilitate PK model-based dose individualization of temsirolimus and the design of future clinical studies in children.

Topics: Adolescent; Antineoplastic Agents; Child; Child, Preschool; Dose-Response Relationship, Drug; Female; Humans; Infant; Male; Models, Biological; Neoplasm Recurrence, Local; Neoplasms; Nonlinear Dynamics; Sirolimus; TOR Serine-Threonine Kinases; Young Adult

Background A wide variety of human cancers exhibit dysregulated c-Met activity that has implications in oncogenesis. Phosphorylation of c-Met results in activation of the PI3K/AKT/mTOR pathway. Combined blockade of c-Met and mTOR pathways has shown efficacy in preclinical studies. Tivantinib is a c-Met inhibitor and temsirolimus is a selective mTOR inhibitor. We aimed to determine the maximum tolerated dose (MTD) and the recommended phase II dose (RP2D), dose-limiting toxicities (DLT), adverse events (AEs), clinical activity and pharmacokinetic (PK) parameters of the combination. Methods This open-label phase I study used a 3 + 3 dose escalation design. Patients (pts) were treated with escalating doses of tivantinib (120-360 mg tablets orally twice daily) and temsirolimus (20 mg IV weekly) followed by dose expansion at the MTD. Separate cohorts were planned for extensive (normal) and poor tivantinib metabolizers based on CYP2C19 genotypes. Cycles were 28 days besides cycle 1 that was 35 days to allow for PK analysis. Results Twenty-nine pts. [median age 58 (range 28-77)] were enrolled (21 in dose escalation and 8 in dose expansion). All were extensive CYP2C19 metabolizers. The most common types of cancer were colorectal, ovarian and non-small cell lung. Sixteen out of 21 and 6 out of 8 pts. were evaluable for DLT evaluation per protocol in the dose escalation and dose expansion phases, respectively. Pts remained on study for a median of 71 days (range 18-296). The MTD and RP2D was tivantinib 240 mg twice daily and temsirolimus 20 mg weekly. DLTs included grade (gr) 4 neutropenia (2 pts.; 1 with gr 3 febrile neutropenia), gr 3 abdominal pain (1 pt) and gr 2 mucositis resulting in inadequate drug delivery. The most common treatment related AEs grade ≥ 2 included: anemia (gr 2 in 9 pts., gr 3 in 3 pts), fatigue (gr 2 in 10 pts), anorexia (gr 2 in 9 pts), hypoalbuminemia (gr 2 in 6 pts., gr 3 in 2 pts), hypophosphatemia (gr 2 in 2 pts., gr 3 in 5 pts) and nausea (gr 2 in 6 pts., gr 3 in 1 pt). One pt. with ovarian cancer had a confirmed partial response and remained on study for 10 months, a second patient with ovarian cancer had stable disease and remained on study for 6 months and a third pt. with squamous cell carcinoma of the tongue had stable disease and remained on study for 7 months. Pharmacokinetic analysis showed that there is no interaction in the plasma concentrations between tivantinib and temsirolimus. Conclusions The combination of tivantinib wi

Topics: Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cytochrome P-450 CYP2C19; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-met; Pyrrolidinones; Quinolines; Sirolimus

Background Dual inhibition of activated MAPK and mTOR signaling pathways may enhance the antitumor efficacy of the MEK 1/2 inhibitor pimasertib and the mTOR inhibitor temsirolimus given in combination. Methods In this phase I study, patients with refractory advanced solid tumors (NCT01378377) received once-weekly temsirolimus plus once-daily oral pimasertib in 21-day cycles in a modified 3 + 3 dose-escalation design. The maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of pimasertib in combination with temsirolimus, safety and pharmacokinetics (PK) were investigated. Results Of 33 patients evaluated, all experienced ≥1 treatment-emergent adverse event (TEAE) and 31 had treatment-related TEAEs, most frequently stomatitis and thrombocytopenia. TEAEs were reversible. No deaths were attributed to treatment. Nine patients had dose-limiting toxicities (stomatitis, thrombocytopenia, serum creatinine phosphokinase increase, visual impairment) and the MTD was determined as 45 mg/day pimasertib plus 25 mg/week temsirolimus. However, due to overlapping toxicities no further investigations were performed and the RP2D was not defined. PK profiles of both agents were not adversely affected. Seventeen patients (17/26 patients) had a best response of stable disease; five had stable disease lasting >12 weeks. Conclusions The RP2D was not defined and the pimasertib plus temsirolimus combination investigated did not warrant further study.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Female; Humans; Male; MAP Kinase Kinase Kinase 1; MAP Kinase Kinase Kinase 2; Maximum Tolerated Dose; Middle Aged; Neoplasms; Niacinamide; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases; Young Adult

Middle East Respiratory Syndrome (MERS) is a novel respiratory illness firstly reported in Saudi Arabia in 2012. It is caused by a new corona virus, called MERS corona virus (MERS-CoV). Most people who have MERS-CoV infection developed severe acute respiratory illness.. This work is done to determine the clinical characteristics and the outcome of intensive care unit (ICU) admitted patients with confirmed MERS-CoV infection.. This study included 32 laboratory confirmed MERS corona virus infected patients who were admitted into ICU. It included 20 (62.50%) males and 12 (37.50%) females. The mean age was 43.99 ± 13.03 years. Diagnosis was done by real-time reverse transcription polymerase chain reaction (rRT-PCR) test for corona virus on throat swab, sputum, tracheal aspirate, or bronchoalveolar lavage specimens. Clinical characteristics, co-morbidities and outcome were reported for all subjects.. Most MERS corona patients present with fever, cough, dyspnea, sore throat, runny nose and sputum. The presence of abdominal symptoms may indicate bad prognosis. Prolonged duration of symptoms before patients' hospitalization, prolonged duration of mechanical ventilation and hospital stay, bilateral radiological pulmonary infiltrates, and hypoxemic respiratory failure were found to be strong predictors of mortality in such patients. Also, old age, current smoking, smoking severity, presence of associated co-morbidities like obesity, diabetes mellitus, chronic heart diseases, COPD, malignancy, renal failure, renal transplantation and liver cirrhosis are associated with a poor outcome of ICU admitted MERS corona virus infected patients.. Plasma HO-1, ferritin, p21, and NQO1 were all elevated at baseline in CKD participants. Plasma HO-1 and urine NQO1 levels each inversely correlated with eGFR (. SnPP can be safely administered and, after its injection, the resulting changes in plasma HO-1, NQO1, ferritin, and p21 concentrations can provide information as to antioxidant gene responsiveness/reserves in subjects with and without kidney disease.. A Study with RBT-1, in Healthy Volunteers and Subjects with Stage 3-4 Chronic Kidney Disease, NCT0363002 and NCT03893799.. HFNC did not significantly modify work of breathing in healthy subjects. However, a significant reduction in the minute volume was achieved, capillary [Formula: see text] remaining constant, which suggests a reduction in dead-space ventilation with flows > 20 L/min. (ClinicalTrials.gov registration NCT02495675).. 3 组患者手术时间、术中显性失血量及术后 1 周血红蛋白下降量比较差异均无统计学意义（. 对于肥胖和超重的膝关节单间室骨关节炎患者，采用 UKA 术后可获满意短中期疗效，远期疗效尚需进一步随访观察。.. Decreased muscle strength was identified at both time points in patients with hEDS/HSD. The evolution of most muscle strength parameters over time did not significantly differ between groups. Future studies should focus on the effectiveness of different types of muscle training strategies in hEDS/HSD patients.. These findings support previous adverse findings of e-cigarette exposure on neurodevelopment in a mouse model and provide substantial evidence of persistent adverse behavioral and neuroimmunological consequences to adult offspring following maternal e-cigarette exposure during pregnancy. https://doi.org/10.1289/EHP6067.. This RCT directly compares a neoadjuvant chemotherapy regimen with a standard CROSS regimen in terms of overall survival for patients with locally advanced ESCC. The results of this RCT will provide an answer for the controversy regarding the survival benefits between the two treatment strategies.. NCT04138212, date of registration: October 24, 2019.. Results of current investigation indicated that milk type and post fermentation cooling patterns had a pronounced effect on antioxidant characteristics, fatty acid profile, lipid oxidation and textural characteristics of yoghurt. Buffalo milk based yoghurt had more fat, protein, higher antioxidant capacity and vitamin content. Antioxidant and sensory characteristics of T. If milk is exposed to excessive amounts of light, Vitamins B. The two concentration of ZnO nanoparticles in the ambient air produced two different outcomes. The lower concentration resulted in significant increases in Zn content of the liver while the higher concentration significantly increased Zn in the lungs (p < 0.05). Additionally, at the lower concentration, Zn content was found to be lower in brain tissue (p < 0.05). Using TEM/EDX we detected ZnO nanoparticles inside the cells in the lungs, kidney and liver. Inhaling ZnO NP at the higher concentration increased the levels of mRNA of the following genes in the lungs: Mt2 (2.56 fold), Slc30a1 (1.52 fold) and Slc30a5 (2.34 fold). At the lower ZnO nanoparticle concentration, only Slc30a7 mRNA levels in the lungs were up (1.74 fold). Thus the two air concentrations of ZnO nanoparticles produced distinct effects on the expression of the Zn-homeostasis related genes.. Until adverse health effects of ZnO nanoparticles deposited in organs such as lungs are further investigated and/or ruled out, the exposure to ZnO nanoparticles in aerosols should be avoided or minimised.

Topics: A549 Cells; Acetylmuramyl-Alanyl-Isoglutamine; Acinetobacter baumannii; Acute Lung Injury; Adaptor Proteins, Signal Transducing; Adenine; Adenocarcinoma; Adipogenesis; Administration, Cutaneous; Administration, Ophthalmic; Adolescent; Adsorption; Adult; Aeromonas hydrophila; Aerosols; Aged; Aged, 80 and over; Aging; Agriculture; Air Pollutants; Air Pollution; Airway Remodeling; Alanine Transaminase; Albuminuria; Aldehyde Dehydrogenase 1 Family; Algorithms; AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase; Alzheimer Disease; Amino Acid Sequence; Ammonia; Ammonium Compounds; Anaerobiosis; Anesthetics, Dissociative; Anesthetics, Inhalation; Animals; Anti-Bacterial Agents; Anti-HIV Agents; Anti-Infective Agents; Anti-Inflammatory Agents; Antibiotics, Antineoplastic; Antibodies, Antineutrophil Cytoplasmic; Antibodies, Monoclonal, Humanized; Antifungal Agents; Antigens, Bacterial; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Antimetabolites, Antineoplastic; Antineoplastic Agents; 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There is crosstalk between the ANG-Tie2 and the PI3K/Akt/mTOR pathways. Combined ANG1/2 and mTOR blockade may have additive anti-cancer activity. The combination of trebananib, an inhibitor of ANG1/2-Tie2 interaction, with temsirolimus was evaluated in patients with advanced solid tumors to determine tolerability, maximum tolerated dose (MTD), and preliminary antitumor activity.. Patients were enrolled using 3 + 3 design, and were given intravenous trebananib and temsirolimus on Day 1, 8, 15 and 22 of a 28-day cycle. Dose limiting toxicities (DLTs) were evaluated during cycle 1. Peripheral blood was collected for evaluation of Tie2-expressing monocytes (TEMs) and thymidine phosphorylase (TP). Sparse pharmacokinetic (PK) sampling for trebananib drug levels was performed on Day 1 and 8 of cycle 2.. Twenty-one patients were enrolled, 6 at dose level (DL) 1, 7 at DL -1, and 8 at DL -2. No effect of temsirolimus on trebananib PK was observed. The most common treatment-related adverse events (AEs) were: fatigue (81 %), edema (62 %), anorexia (57 %), nausea (52 %), rash (43 %) and mucositis (43 %). The most common grade ≥ 3 AEs included lymphopenia (28 %) and fatigue (28 %). The MTD was exceeded at DL-2. Of 18 response evaluable patients, 1 partial response was observed (ER+/HER2-/PIK3CA mutant breast cancer) and 4 patients had prolonged SD ≥ 24 weeks. No correlation with clinical benefit was observed with change in number TEMs or TP expression in TEMs with treatment.. The MTD was exceeded at trebananib 10 mg/kg weekly and temsirolimus 20 mg weekly, with frequent overlapping toxicities including fatigue, edema, and anorexia.

Topics: Adult; Aged; Anorexia; Antineoplastic Combined Chemotherapy Protocols; Edema; Fatigue; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Recombinant Fusion Proteins; Sirolimus; Treatment Outcome

Bevacizumab and temsirolimus are active agents in advanced solid tumors. Temsirolimus inhibits mTOR in the PI3 kinase/AKT/mTOR pathway as well as CYP2A, which may be a resistance mechanism for cetuximab. In addition, temsirolimus attenuates upregulation of HIF-1α levels, which may be a resistance mechanism for bevacizumab.. We analyzed safety and responses in 21 patients with advanced solid tumors treated with bevacizumab, cetuximab, and temsirolimus.. The median age of patients was 60 years (range, 23-80 years). The median number of prior systemic therapies was 3 (range, 1-6). The maximum tolerated dose (MTD) was determined to be bevacizumab 10 mg/kg biweekly, temsirolimus 5 mg weekly and cetuximab 100/75 mg/m2 weekly. Grade 3 or 4 toxicities were seen in 52% of patients with the highest prevalence being hyperglycemia (14%) and hypophosphatemia (14%). Eighteen of the 21 patients were evaluable for response. Three patients were taken off the study before restaging for toxicities. Partial response (PR) was observed in 2/18 patients (11%) and stable disease (SD) lasting ≥ 6 months was observed in 4/18 patients (22%) (total = 6/18 (33%)). In 8 evaluable patients with squamous cell carcinoma of the head and neck (HNSCC) there were partial responses in 2/8 (25%) patients and SD ≥ 6 months in 1/8 (13%) patients (total = 3/8, (38%)).. The combination of bevacizumab, cetuximab, and temsirolimus showed activity in HNSCC; however, there were numerous toxicities reported, which will require careful management for future clinical development.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Cetuximab; Female; Follow-Up Studies; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Prognosis; Sirolimus; Survival Rate

Mammalian target of rapamycin (mTOR) inhibitors like temsirolimus may result in undesirable AKT upregulation. Metformin inhibits mTOR through different mechanisms and may enhance temsirolimus's antitumor activity. We conducted an open-label phase I dose escalation trial of this drug combination in patients with advanced/refractory cancers.. Temsirolimus, 25 mg weekly, was combined with an escalating daily dose of metformin (level 1: 500; level 2: 1000; level 3: 1500; level 4: 2000 mg) by utilizing a standard 3 + 3 trial design. Treatment was administered in 28-day cycles following initial 2-week metformin titration during the first cycle.. Twenty-one patients (median age, 56 years) with sarcoma (n = 8), colorectal (n = 3), endometrial (n = 4), uterine carcinosarcoma (n = 2), ovarian (n = 2), and other (n = 2) cancers were enrolled. Patients had received median of four prior systemic treatments. Two dose-limiting toxicities were observed (grade 3 mucositis, grade 3 renal failure); both patients continued treatment after dose modification. Fifty-six percent patients had stable disease as best response; clinical benefit rate was 22 %. Patients continued treatment for median of 11 weeks.. Combination temsirolimus/metformin was well tolerated with modestly promising effectiveness among this heavily pretreated patient cohort. We recommend a dose of temsirolimus 25 mg weekly and metformin 2000 mg daily for phase II study.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Male; Maximum Tolerated Dose; Metformin; Middle Aged; Neoplasms; Response Evaluation Criteria in Solid Tumors; Sirolimus; TOR Serine-Threonine Kinases; Young Adult

Sirolimus, an oral mTOR inhibitor, may complement the anti-angiogenic and anti-tumor activity of sunitinib, an oral small molecule inhibitor of multiple receptor tyrosine kinases, by vertical disruption of vascular epithelial growth factor receptor (VEGFR) signaling, by reducing the compensatory production of VEGF in sunitinib-treated patients and also by directly inhibiting tumor cell proliferation. We conducted this phase 1 study to investigate the maximum tolerated dose (MTD) for this combination of sunitinib and sirolimus in humans.. Sunitinib was given at 50 mg daily × 28 every 6 weeks. The first cohort received sunitinib alone for cycle 1 (50 mg daily for 2 weeks followed by 2 weeks off) and received sunitinib at standard dose 50 mg daily for 4 weeks followed by 2 weeks off in combination with sirolimus 4 mg weekly; this dose and schedule were further investigated in second cohort. The third cohort received decreased dose of sunitinib at 37.5 mg daily for 4 weeks followed by 2 weeks off in combination with sirolimus at 4 mg weekly. Sirolimus dose was escalated to 8 mg weekly in fourth cohort.. Eighteen patients with ECOG PS of 0 or 1 were enrolled, median age 57 years (range 24-76), M:F ratio: 11:7. Median number of prior treatments is 2 (range 0-5); six patients had no prior systemic therapy. Half of patients from the first two cohorts required dose reduction or early discontinuation of treatment; therefore, sunitinib dose was decreased to 37.5 mg daily in third and fourth cohort. In third and fourth cohort, one-third of patients required dose modification during cycle 1 or cycle 2. Multiple patients had significant toxicities including fatigue and hand-foot syndrome. One patient developed interstitial pneumonitis, and one patient died suddenly on day 8 due to progressive disease. There were six patients who tolerated four or more cycles. Among these six patients, two patients with renal cell carcinoma (RCC) achieved partial response; one subsequently underwent surgical resection of residual renal mass and lymph node dissection and achieved complete response afterward. One with metastatic melanoma also achieved complete response after metastatectomy. There was no apparent pharmacokinetic interaction between sunitinib and sirolimus. 4 mg weekly sirolimus did not reduce the sunitinib-induced circulating VEGF production but stimulated more VEGF production through some unknown compensatory mechanism.. Toxicity precluded dose escalation of weekly sirolimus in combination with a standard sunitinib dose/schedule. These results suggest caution when combining targeted agents lacking specificity for tumor signaling or vasculature.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Indoles; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Pyrroles; Sirolimus; Sunitinib; TOR Serine-Threonine Kinases; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2; Young Adult

Dalotuzumab is a highly specific, humanised immunoglobulin G1 monoclonal antibody against insulin-like growth factor receptor 1. This multicenter phase 1 study (NCT01431547) explored the safety and pharmacokinetics of dalotuzumab monotherapy (part 1) and the combination of dalotuzumab with the mammalian target of rapamycin inhibitor ridaforolimus (part 2) in paediatric patients with advanced solid tumours.. Dalotuzumab was administered intravenously every 3 weeks starting at 900 mg/m(2) and escalating to 1200 and 1500 mg/m(2). Combination therapy included intravenous dalotuzumab at the defined single-agent recommended phase 2 dose (RP2D) and oral ridaforolimus 28 mg/m(2) daily (days 1-5), repeated weekly. Pharmacokinetic studies were performed to evaluate the mean serum trough dalotuzumab concentration, which guided the RP2D.. Twenty-four patients were enrolled (part 1, n = 20; part 2, n = 4). No dose-limiting toxicities were observed in patients receiving dalotuzumab alone. One patient experienced dose-limiting stomatitis in the combination arm. Pharmacokinetic data showed dose-dependent increases in exposure (area under the curve from zero to infinity [AUC0-∞]) (87,900, 164,000, and 186,000 h*mg/ml for the 900, 1200, and 1500 mg/m(2) dose levels, respectively), maximum serum concentration (Cmax) (392, 643, and 870 mg/ml), and serum trough concentration (Ctrough) (67.1, 71.6, and 101 mg/ml). The mean half-life was 265, 394, and 310 h, respectively. Dalotuzumab pharmacokinetics were not affected by coadministration with ridaforolimus. One of six patients with Ewing sarcoma had confirmed partial response to dalotuzumab monotherapy at 900 mg/m(2). Time to response was 41 d, and progression occurred at 126 d.. Dalotuzumab was well tolerated in paediatric patients with advanced solid malignancies. The RP2D of dalotuzumab is 900 mg/m(2) (ClinicalTrials.gov identifier: NCT01431547, Protocol PN062).

Topics: Adolescent; Antibiotics, Antineoplastic; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Child; Child, Preschool; Female; Humans; Male; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Preclinical models suggest that histone deacetylase (HDAC) and mammalian target of rapamycin (mTOR) inhibitors have synergistic anticancer activity. We designed a phase I study to determine the safety, maximum tolerated dose (MTD), recommended phase II dose (RP2D), and dose-limiting toxicities (DLTs) of combined mTOR inhibitor sirolimus (1 mg-5 mg PO daily) and HDAC inhibitor vorinostat (100 mg-400 mg PO daily) in patients with advanced cancer. Seventy patients were enrolled and 46 (66%) were evaluable for DLT assessment since they completed cycle 1 without dose modification unless they had DLT. DLTs comprised grade 4 thrombocytopenia (n = 6) and grade 3 mucositis (n = 1). Sirolimus 4 mg and vorinostat 300 mg was declared RP2D because MTD with sirolimus 5 mg caused significant thrombocytopenia. The grade 3 and 4 drug-related toxic effects (including DLTs) were thrombocytopenia (31%), neutropenia (8%), anemia (7%), fatigue (3%), mucositis (1%), diarrhea (1%), and hyperglycemia (1%). Of the 70 patients, 35 (50%) required dose interruption or modification and 61 were evaluable for response. Partial responses were observed in refractory Hodgkin lymphoma (-78%) and perivascular epithelioid tumor (-54%), and stable disease in hepatocellular carcinoma and fibromyxoid sarcoma. In conclusion, the combination of sirolimus and vorinostat was feasible, with thrombocytopenia as the main DLT. Preliminary anticancer activity was observed in patients with refractory Hodgkin lymphoma, perivascular epithelioid tumor, and hepatocellular carcinoma.

Topics: Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Female; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Vorinostat; Young Adult

Ridaforolimus is an investigational, potent, selective mTOR inhibitor. This study was conducted to determine the recommended phase 2 dose (RP2D), maximum tolerated dose, safety, pharmacokinetics, and antitumor activity of oral ridaforolimus in children with advanced solid tumors.. In this phase 1, multicenter, open-label study in children aged 6 to <18 years with advanced solid tumors, ridaforolimus was administered orally for 5 consecutive days/week in 28-day cycles until progression, unacceptable toxicity, or consent withdrawal. Dose started at 22 mg/m2 and increased to 28 mg/m2 and 33 mg/m2, followed by expansion at the RP2D.. Twenty patients were treated; 18 were evaluable for dose-limiting toxicities. One dose-limiting toxicity (grade 3 increased alanine aminotransferase) occurred in 1 patient at 33 mg/m2. Dose escalation concluded at 33 mg/m2; the maximum tolerated dose was not determined. The most common treatment-related adverse events (frequency ≥40%) were manageable grade 1-2 stomatitis, thrombocytopenia, hypertriglyceridemia, increased alanine aminotransferase, fatigue, hypercholesterolemia, anemia, and increased aspartate aminotransferase. Ridaforolimus exposure at 28 mg/m2 and 33 mg/m2 exceeded adult target levels. The RP2D for oral ridaforolimus in children was defined as 33 mg/m2. Four patients received at least 4 cycles; 2 with pineoblastoma and diffuse intrinsic pontine glioma had stable disease for 12 and 46 cycles, respectively.. Ridaforolimus is orally bioavailable and well tolerated in children with advanced solid tumors. The RP2D (33 mg/m2, 5 days/week) exceeds the adult RP2D. The favorable toxicity and pharmacokinetic profiles may allow for combination therapy, a promising therapeutic option in pediatric malignancies.

Topics: Administration, Oral; Adolescent; Adult; Antineoplastic Agents; Child; Combined Modality Therapy; Drug Dosage Calculations; Female; Humans; Male; Neoplasm Staging; Neoplasms; Sirolimus; Stomatitis; TOR Serine-Threonine Kinases

This phase Ib trial investigated the safety, tolerability, and recommended phase II dose and schedule of the MEK inhibitor trametinib in combination with the mammalian target of rapamycin (mTOR) inhibitor everolimus. Secondary objectives included pharmacokinetic (PK) characterization and evaluation of clinical activity.. A total of 67 patients with advanced solid tumors were enrolled in this open-label, single-arm, dose-escalation study. Dose escalation followed a 3 + 3 design. Patients were assigned to one of 10 different cohorts, involving either daily dosing with both agents or daily dosing with trametinib and intermittent everolimus dosing. This included an expansion cohort comprising patients with pancreatic tumors. PKs samples were collected predose, as well as 1, 2, 4, and 6 h post-dose on day 15 of the first treatment cycle.. Concurrent treatment with trametinib and everolimus resulted in frequent treatment-related adverse events, including mucosal inflammation (40%), stomatitis (25%), fatigue (54%), and diarrhea (42%). PK assessment did not suggest drug-drug interactions between these two agents. Of the 67 enrolled patients, 5 (7%) achieved partial response (PR) to treatment and 21 (31%) displayed stable disease (SD). Among the 21 patients with pancreatic cancer, PR was observed in 1 patient (5%) and SD in 6 patients (29%).. This study was unable to identify a recommended phase II dose and schedule of trametinib in combination with everolimus that provided an acceptable tolerability and adequate drug exposure.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Drug Administration Schedule; Everolimus; Female; Humans; Male; MAP Kinase Kinase 1; MAP Kinase Kinase 2; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Pyridones; Pyrimidinones; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Young Adult

To determine the MTD, dose-limiting toxicities (DLT), pharmacokinetics, and biologic effects of cixutumumab administered in combination with temsirolimus to children with refractory solid tumors.. Cixutumumab and temsirolimus were administered intravenously once every 7 days in 28-day cycles. Pharmacokinetic and biology studies, including assessment of mTOR downstream targets in peripheral blood mononuclear cells, were performed during the first cycle.. Thirty-nine patients, median age 11.8 years (range, 1-21.5), with recurrent solid or central nervous system tumors were enrolled, of whom 33 were fully assessable for toxicity. There were four dose levels, which included two dose reductions and a subsequent intermediated dose escalation: (i) IMC-A12 6 mg/kg, temsirolimus 15 mg/m(2); (ii) IMC-A12 6 mg/kg, temsirolimus 10 mg/m(2); (iii) IMC-A12 4 mg/kg, temsirolimus 8 mg/m(2); and (iv) IMC-A12 6 mg/kg, temsirolimus 8 mg/m(2). Mucositis was the predominant DLT. Other DLTs included hypercholesterolemia, fatigue, thrombocytopenia, and increased alanine aminotransferase. Target inhibition (decreased S6K1 and PAkt) in peripheral blood mononuclear cells was noted at all dose levels. Marked interpatient variability in temsirolimus pharmacokinetic parameters was noted. At 8 mg/m(2), the median temsirolimus AUC was 2,946 ng • h/mL (range, 937-5,536) with a median sirolimus AUC of 767 ng • h/mL (range, 245-3,675).. The recommended pediatric phase II doses for the combination of cixutumumab and temsirolimus are 6 mg/kg and 8 mg/m(2), respectively.

Topics: Adolescent; Adult; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Child; Child, Preschool; Dose-Response Relationship, Drug; Female; Humans; Infant; Male; Maximum Tolerated Dose; Neoplasms; Sirolimus; Young Adult

The optimal weekly oral dose of sirolimus and intravenous nanoparticle albumin-bound paclitaxel (nab-paclitaxel) were evaluated.. A phase 1b study was performed to evaluate escalating doses of oral sirolimus (5-60 mg) on days 2, 9, and 16 with intravenous nab-paclitaxel (100 mg/m(2) ) on days 1, 8, and 15 in a 28-day cycle. A run-in treatment of nab-paclitaxel (day -14) and sirolimus (day -7) was administered for pharmacokinetic and pharmacodynamic assessments. Clinical trial endpoints included dose-limiting toxicities (DLTs), maximum tolerated doses, and response rates. Pharmacodynamics included immunohistochemistry for phosphatase and tensin homolog, mammalian target of rapamycin (mTOR), AKT, phosphorylated AKT, S6K1, and phosphorylated S6K1; exploratory gene expression analysis; and [(18) F]fludeoxyglucose (FDG) positron emission tomography.. Twenty-three patients with advanced solid tumors were treated. Fifteen patients had prior taxane therapy. Twenty-two patients were evaluable for responses. One patient had a complete response, and 5 patients had a partial response (3 confirmed). DLTs were seen in 1 patient each at 10 (grade 3 dyspnea/hypoxia) and 40 mg (grade 4 leukopenia/neutropenia) and in 2 patients at 60 mg (grade 3 fatigue and grade 4 pericardial effusion). Patients with higher expression of posttreatment AKT and a greater decline in FDG activity were more likely to have a treatment response or stable disease.. Sirolimus showed an acceptable safety profile at a weekly dose of 40 mg with weekly intravenous nab-paclitaxel at 100 mg/m(2) on days 1, 8, and 15 every 28 days. The posttreatment AKT score and changes in FDG activity may have roles as early predictors of responses to mTOR inhibitors.

Topics: Adult; Aged; Albumin-Bound Paclitaxel; Albumins; Antineoplastic Combined Chemotherapy Protocols; Cohort Studies; Female; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Nanoparticles; Neoplasms; Paclitaxel; Positron-Emission Tomography; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Cixutumumab (a humanized monoclonal antibody against insulin-like growth factor-1 receptor [IGF-1R]) and the mammalian target of rapamycin (mTOR) inhibitor temsirolimus were combined in a phase I study of patients with advanced cancer. We investigated the prevalence of metabolic toxicities, their management, and impact on outcome.. The temsirolimus dose was 25 mg or 37.5 mg i.v. weekly with escalating doses of cixutumumab (3, 5, or 6 mg/kg i.v. weekly). No patients with diabetes or hyperlipidemia at baseline were eligible until the expansion cohort. We assessed metabolic derangements in our patient cohort, their management, and their association with tumor shrinkage, time to progression (TTP) and overall survival (OS).. Of the 57 patients analyzed, hyperglycemia was seen in 36 (63%) (grade 1-2: 33 [58%]; grade 3-4: 3 [5%]). The median blood sugar level (fasting and nonfasting) across cohorts was 149 mg/dL (upper limit of normal: 110 mg/dL). No patient developed diabetic ketoacidosis or nonketotic hyperosmolar coma or pancreatitis during treatment. Median maximum triglyceride, cholesterol, and low-density lipoprotein levels achieved were 247 mg/dL (range: 65-702 mg/dL), 243 mg/dL (range: 103-424 mg/dL), and 153 mg/dL (range 50-375 mg/dL), respectively. Higher glucose levels were associated with more RECIST tumor shrinkage (r = -.30 [95% confidence interval: -.52, -.03; p = .03]). There was no association between metabolic toxicities of the mTOR and IGF-1R combination and TTP or OS.. The combination of temsirolimus and cixutumumab was safe and resulted in manageable metabolic toxicities. More tumor shrinkage was seen in patients who developed these adverse events. Although perhaps limited by the small number of patients, no significant association was discerned between hyperglycemia, hypertriglyceridemia, or hypercholesterolemia and TTP or OS.. Results of this study show that the combination of temsirolimus and cixutumumab is safe. The most common side effects, hyperglycemia and hyperlipidemia, are tolerable and manageable. This combination of therapies should not be withheld from diabetic patients and patients with high cholesterol levels. Collaboration between oncologist and endocrinologist allows for individualized treatment and better control of these adverse events, with few dose interruptions and reductions. Supportive care and close monitoring is needed. Those patients who develop hyperglycemia or hypercholesterolemia may benefit more from the drug.

Topics: Adolescent; Adult; Aged; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Female; Humans; Hypercholesterolemia; Hyperglycemia; Hyperlipidemias; Male; Middle Aged; Neoplasms; Receptor, IGF Type 1; Sirolimus; Survival Analysis; TOR Serine-Threonine Kinases; Treatment Outcome; Young Adult

The PI3K/Akt/mTOR signaling pathway is aberrantly activated in many cancers. Combining ridaforolimus, an mTOR inhibitor, with MK-2206, an Akt inhibitor, may more completely block the PI3K pathway and inhibit tumor growth.. This phase I study assessed dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) for the combination of oral ridaforolimus plus oral MK-2206 in patients with advanced solid tumors. Efficacy was evaluated in patients with biomarker-identified estrogen receptor-positive breast cancer (low RAS gene signature and high Ki67 index) or castration-resistant prostate cancer (PTEN deficiency) with PI3K pathway addiction.. Thirty-five patients were enrolled: 11 patients in part A (three breast cancer) and 24 biomarker-eligible patients in part B (16 breast cancer, eight prostate cancer). One patient with breast cancer from part A was also found to be biomarker-eligible when tested after she had clinical response. The MTD was 10 mg/d ridaforolimus 5 d/wk + 90 mg/wk MK-2206; 1 of 17 patients experienced DLT (grade 3 rash) at this dose. The most common adverse events at MTD were rash (44.4%), stomatitis (38.9%), diarrhea (27.8%), and decreased appetite (27.8%). By investigator assessment, 2 of 16 (12.5%) evaluable patients with breast cancer had partial response; by central assessment, 2 of 14 (14.3%) evaluable patients had complete response. Two patients had durable stable disease (SD) for 416 and 285 days, respectively. No patients with prostate cancer responded; one patient had SD for ≥ 6 months.. Combination ridaforolimus and MK-2206 showed promising activity and good tolerability in heavily pretreated patients with hormone-positive and -negative breast cancer exhibiting PI3K pathway dependence.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Biomarkers; Female; Heterocyclic Compounds, 3-Ring; Humans; Male; Middle Aged; Neoplasm Staging; Neoplasms; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Retreatment; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Young Adult

Cancer is a manifestation of aberrant cellular proliferation, and the cell cycle is one of the most successfully drugged targets in oncology. No prior study has been reported that simultaneously targets the 3 principal cell cycle phases populated by proliferating cells--G1, S, and G2/M.. Temsirolimus (G1 inhibitor), topotecan (S inhibitor), and bortezomib (G2/M inhibitor) were administered in combination to patients with advanced malignancies using a 3+3 dose escalation schedule to assess the safety and establish the maximum tolerated dose (primary endpoints) of this cell cycle targeting approach. An in silico pharmacodynamic model using established effects of each of these agents on the cell cycle was used to validate the regimen and to guide the dosing regimen.. Sixty-two subjects were enrolled. The most common adverse events and dose-limiting toxicities were cytopenias, consistent with the cell cycle targeting approach employed. All cytopenias resolved to baseline values upon holding study drug administration. The maximum tolerated dose was temsirolimus 15 mg/kg IV D1, 8, 15; topotecan 2.8 mg/m(2) IV D1, 8; and bortezomib 0.6 mg/m2 IV D1, 4, 8, 11 [DOSAGE ERROR CORRECTED] of a 21-day cycle. In silico modeling suggests the regimen induces cell population shifts from G2/M and S phases to G1 phase and the quiescent G0 phase. Eighteen percent of subjects (11/62) achieved partial response (n = 2, serous ovarian and papillary thyroid) or stable disease for > 6 months (n = 9).. Combining drugs with inhibitory activity of G1 phase, S phase, and G2/M phase is safe and warrants further evaluation.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Bortezomib; Computer Simulation; Disease Progression; Disease-Free Survival; Drug Administration Schedule; Female; G1 Phase Cell Cycle Checkpoints; G2 Phase Cell Cycle Checkpoints; Humans; Kaplan-Meier Estimate; Male; Maximum Tolerated Dose; Middle Aged; Models, Biological; Molecular Targeted Therapy; Neoplasms; S Phase Cell Cycle Checkpoints; Sirolimus; Texas; Time Factors; Topotecan; Treatment Outcome; Young Adult

The combination of vinblastine and mammalian target of rapamycin (mTOR) inhibitor sirolimus inhibits the growth of neuroblastoma xenografts through pro-apoptotic and anti-angiogenic mechanisms. This phase I study aimed to explore the safety and toxicity of this combination in pediatric patients with advanced solid tumors.. Patients ≤21 years of age with recurrent/refractory solid tumors (including CNS) were eligible. Sirolimus was administered daily by mouth or nasogastric (NG) tube, with doses adjusted to achieve a target trough concentration of 10-15 ng/ml, with weekly intravenous vinblastine (dose escalated 4-6 mg/m(2)/dose according to 3 + 3 phase I design).. Fourteen patients were enrolled (median age 8.7 years; range 2.3-19) of whom 12 were evaluable for toxicity and 11 for response. One patient experienced a dose-limiting toxicity (grade 3 mucositis) at the highest vinblastine dose level. Myelosuppression was the most common toxicity. Dose-adjusted sirolimus trough concentrations were significantly lower in patients receiving drug via NG tube (1.50 ± 0.75 ng/ml/mg vs. 2.25 ± 1.07 ng/ml/mg for oral administration). Correlative biomarker analysis demonstrated a significant reduction in serum concentration of soluble vascular endothelial growth factor receptor (sVEGFR2) at 28 days compared to baseline consistent with inhibition of angiogenesis. One patient had a partial response and three had stable disease for more than 3 months.. The combination of mTOR inhibitor and vinblastine given over an extended continuous schedule is safe, associated with a reduction in circulating angiogenic factor (CAF) VEGFR2 and resulted in clinical responses. Future studies using the intravenously administered mTOR inhibitor temsirolimus are planned.

Topics: Adolescent; Antineoplastic Combined Chemotherapy Protocols; Child; Child, Preschool; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Female; Humans; Male; Maximum Tolerated Dose; Neoplasm Recurrence, Local; Neoplasms; Receptors, Vascular Endothelial Growth Factor; Sirolimus; Vascular Endothelial Growth Factor A; Vinblastine; Young Adult

Preclinical and clinical studies suggest mTOR (mammalian target of rapamycin) inhibitors may have metabolic and antiangiogenic effects, and synergize with epidermal growth factor pathway inhibitors. Therefore, a phase 1/pharmacodynamic trial of everolimus with cetuximab was performed.. A total of 29 patients were randomized to a run-in of oral everolimus (30, 50, or 70 mg) or cetuximab (400 mg/m(2) loading, 250 mg/m(2) maintenance) weekly, followed by the combination in this dose-escalation study. Primary endpoints were phase 2 dose and toxicity characterization. [(18)F]Fluorodeoxyglucose positron emission tomography (FDG-PET) was performed as a pharmacodynamic marker of mTOR inhibition, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed as an indicator of tumor perfusion changes, at 3 time points.. Everolimus and cetuximab were tolerable at full doses, with an expected toxicity profile. Dose-limiting toxicities in the everolimus 70 mg group included grade 3 skin toxicity in 2 patients, and mucositis in 1 patient. Of 16 patients evaluable for response, 5 had stable disease lasting 4 to 19 months. Mean change in maximum standardized uptake value (SUV(max)) for those treated initially with everolimus was -24% (2% to -54%), and with cetuximab was -5% (-23 to 36%). The K(trans) measured by DCE-MRI did not decrease, regardless of run-in drug.. Everolimus and cetuximab can be safely administered at standard doses, and are associated with prolonged disease control. The recommended phase 2 dose of oral weekly everolimus is 70 mg in combination with standard cetuximab. Imaging studies reveal that metabolic inhibition by everolimus alone and in combination with cetuximab predominates over changes in tumor perfusion in this patient population.

Topics: Adult; Aged; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Cetuximab; Dose-Response Relationship, Drug; Everolimus; Female; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Neoplasms; Radionuclide Imaging; Radiopharmaceuticals; Sirolimus; TOR Serine-Threonine Kinases

mTOR inhibitors have activity in pediatric tumor models. A phase I trial of the mTOR inhibitor temsirolimus (TEM) with irinotecan (IRN) and temozolomide (TMZ) was conducted in children with recurrent/refractory solid tumors, including central nervous system (CNS) tumors.. Escalating doses of intravenous (IV) TEM were administered on days 1 and 8 of 21-day cycles. IRN (50 mg/m(2)/dose escalated to a maximum of 90 mg/m(2)/dose) and TMZ (100 mg/m(2)/dose escalated to a maximum of 150 mg/m(2)/dose) were administered orally (PO) on days 1-5. When maximum tolerated doses (MTD) were identified, TEM frequency was increased to weekly.. Seventy-one eligible pts (median age 10.9 years, range 1.0-21.5) with neuroblastoma (16), osteosarcoma (7), Ewing sarcoma (7), rhabdomyosarcoma (4), CNS (22) or other (15) tumors were enrolled. Dose-limiting hyperlipidemia occurred in two patients receiving oral corticosteroids. The protocol was subsequently amended to preclude chronic steroid use. The MTD was identified as TEM 35 mg/m(2) IV weekly, with IRN 90 mg/m(2) and TMZ 125 mg/m(2) PO on days 1-5. At higher dose levels, elevated serum alanine aminotransferase and triglycerides, anorexia, and thrombocytopenia were dose limiting. Additional ≥ grade 3 regimen-related toxicities included leukopenia, neutropenia, lymphopenia, anemia, and nausea/vomiting. Six patients had objective responses confirmed by central review; three of these had sustained responses through ≥ 14 cycles of therapy.. The combination of TEM (35 mg/m(2)/dose IV weekly), IRN (90 mg/m(2)/dose days 1-5) and TMZ (125 mg/m(2)/dose days 1-5) administered PO every 21 days is well tolerated in children. Phase 2 trials of this combination are ongoing.

Topics: Adolescent; Adult; Antineoplastic Combined Chemotherapy Protocols; Camptothecin; Child; Child, Preschool; Dacarbazine; Female; Follow-Up Studies; Humans; Infant; Irinotecan; Male; Maximum Tolerated Dose; Neoplasm Recurrence, Local; Neoplasms; Prognosis; Remission Induction; Sirolimus; Temozolomide; Young Adult

Human epidermal growth factor (HER) -mediated signaling is critical in many cancers, including subsets of breast and lung cancer. HER family members signal via the phosphatidylinositide 3-kinase (PI3K) -AKT/protein kinase B-mammalian target of rapamycin (mTOR) cascade; mTOR activation is critical for the expression of multiple contributors to tumor growth and invasion. On the basis of preclinical data suggesting synergy of HER2 inhibition and mTOR inhibition in breast and lung cancer models, we conducted a phase I combination study of neratinib, a small-molecule irreversible pan-HER tyrosine kinase inhibitor, and temsirolimus, an mTOR inhibitor, in patients with advanced solid tumors.. This study enrolled patients to dosing combinations of neratinib and temsirolimus. The primary objective was to estimate the toxicity contour of the combination and establish recommended phase II doses.. Sixty patients were treated on 12 of 16 possible dosing combinations. Diarrhea was the most common drug-related (93%) and dose-limiting toxicity (DLT), constituting four of 10 DLTs. Dose-limiting grade 3 metabolic abnormalities were also observed. Other frequent drug-related toxicities included nausea, stomatitis (both 53%), and anemia (48%). Two maximum-tolerated dose combinations were identified: 200 mg of neratinib/25 mg of temsirolimus and 160 mg of neratinib/50 mg of temsirolimus. Responses were noted in patients with HER2-amplified breast cancer resistant to trastuzumab, HER2-mutant non-small-cell lung cancer, and tumor types without identified mutations in the HER-PI3K-mTOR pathway.. The combination of neratinib and temsirolimus was tolerable and demonstrated antitumor activity in multiple tumor types, warranting further evaluation.

Topics: Aged; Anemia; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; Breast Neoplasms; Diarrhea; Dose-Response Relationship, Drug; Female; Gene Amplification; Humans; Lung Neoplasms; Male; Middle Aged; Mutation; Nausea; Neoplasms; Phosphatidylinositol 3-Kinases; Quinolines; Receptor, ErbB-2; Signal Transduction; Sirolimus; Stomatitis; TOR Serine-Threonine Kinases; Treatment Outcome

LY2584702 tosylate (hereafter referred to as LY2584702) is an oral, selective ATP competitive inhibitor of p70 S6 kinase. Preclinical studies with LY2584702 demonstrated significant synergistic activity with erlotinib and everolimus. The primary objective was to determine a phase II dose and schedule. Secondary objectives included evaluation of safety, toxicity and pharmacokinetics of LY2584702 in combination with erlotinib or everolimus.. Patients with advanced solid tumours were treated with a total daily dose of 50-200mg of LY2584702 in combination with erlotinib 150 mg once daily (Arm A) or everolimus 10mg once daily (Arm B). Dose escalation was based on 3+3 design and used the Common Terminology Criteria for Adverse Events Version 4.0.. Twenty-nine patients were enrolled, 17 in Arm A and 12 in Arm B. Dose limiting toxicities (DLTs) in cycle 1 were observed in Arm A in four patients and consisted of Grade 3 vomiting, hypophosphataemia, pulmonary embolism and decreased clotting factor V. No DLTs were observed in Arm B at cycle 1, and the most frequent treatment-emergent adverse events related to study drug were: fatigue, anorexia, diarrhoea, nausea and vomiting. Seven patients received ≥4 cycles (3 in A, 4 in B). Best overall response was stable disease. Exposure accumulation of LY2584702 occurred with BID (twice daily) dosing. Exposure of erlotinib increased when administered in combination with LY2584702.. LY2584702 was not well tolerated when administered with erlotinib, therefore this combination is not feasible. The combination with everolimus was better tolerated but yielded very limited clinical benefit.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Anorexia; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; Diarrhea; Dose-Response Relationship, Drug; Drug Administration Schedule; Erlotinib Hydrochloride; Everolimus; Fatigue; Female; Humans; Male; Metabolic Clearance Rate; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyrazoles; Pyrimidines; Quinazolines; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; Time Factors; Treatment Outcome; Vomiting

Molecular alterations of the PI3K and Ras pathways often occur in human cancer. In this trial, the pharmacokinetics, toxicity, and activity of two drugs inhibiting these pathways-everolimus and sorafenib-were investigated.. Thirteen patients with progressing solid tumors were treated with everolimus and sorafenib, according to a 3+3 scheme. Patients were selected on the basis of immunohistochemical expression of tumor molecular targets, including phospho-AKT, -p70S6K, and -ERK1/2.. The daily recommended dose identified was 2.5 mg of everolimus and 600 mg of sorafenib. Dose-limiting toxicities included grade 3 asthenia and hand-foot skin reaction. No grade 4 adverse events were observed. The most frequent grade 3 toxicities were hypophosphatemia (30.8%), alanine aminotransferase level increase, asthenia, and anorexia (14%). No pharmacokinetic interactions were identified between everolimus and sorafenib. Of 12 evaluable patients, we observed 2 partial responses, with greater than 10% shrinkage in an additional 5 patients. Objective responses were observed in one patient with a thymoma and in one patient with a lung adenocarcinoma. Tumor shrinkage that did not qualify as a partial response was seen in an abdominal leiomyosarcoma and in adenoid cystic carcinomas.. The combination of everolimus and sorafenib is safe. The tumor activity observed in different tumor types could be the result of the combined action of these drugs as well as the molecular selection of the treated population. Further research is warranted to better investigate drugs simultaneously blocking the PI3K and the Ras pathways and to refine patient selection.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Everolimus; Extracellular Signal-Regulated MAP Kinases; Humans; Neoplasms; Niacinamide; Phenylurea Compounds; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; ras Proteins; Sirolimus; Sorafenib

To define maximum tolerated dose (MTD), toxicities, and pharmacodynamics of capecitabine, oxaliplatin, bevacizumab, and everolimus in advanced solid tumor patients.. This was a standard "3 + 3" dose-escalation trial. All subjects received bevacizumab 7.5 mg/kg on day 1 of each cycle. Doses for capecitabine, oxaliplatin and everolimus were modified per dose limiting toxicity (DLT). Baseline and on-treatment plasma biomarkers were analyzed. Archived tumor mRNA levels were evaluated for NRP1, NRP2 and VEGF-A isoforms.. Twenty-nine patients were evaluable for toxicity and 30 for efficacy. Two DLTs were observed in cohort 1 and one DLT each was observed in cohort -1 and -1b. Grade ≥3 toxicities included neutropenia, hypertension, perforation/fistula/hemorrhage, hypertriglyceridemia, diarrhea, and thromboembolism. Twelve subjects experienced partial response (PR); 12 had stable disease as best response. Three of seven chemorefractory metastatic colorectal cancer (mCRC) subjects experienced PR; 8 of 15 chemonaive mCRC subjects experienced PR. Plasma TβRIII and IL-6 increased on treatment but without correlation to outcome. Increased VEGF165 levels significantly correlated with longer progression free survival.. Everolimus with full dose capecitabine, oxaliplatin, and bevacizumab had unacceptable toxicity. MTD was: everolimus 5 mg daily; capecitabine 680 mg/m(2) BID days 1-14; oxaliplatin 100 mg/m(2) and bevacizumab 7.5 mg/kg, day 1. Activity was noted in mCRC.

Topics: Angiogenesis Inhibitors; Antibodies, Monoclonal, Humanized; Antimetabolites, Antineoplastic; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Biomarkers, Tumor; Capecitabine; Deoxycytidine; Everolimus; Female; Fluorouracil; Humans; Immunosuppressive Agents; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Neuropilin-1; Neuropilin-2; Organoplatinum Compounds; Oxaliplatin; RNA, Messenger; Sirolimus; Vascular Endothelial Growth Factor A

A Phase I trial of the 2-drug regimen of everolimus plus gemcitabine (Cohort I) and the 3-drug regimen of everolimus plus gemcitabine and cisplatin (Cohort II) was performed to determine the maximally tolerated dose (MTD) of both combinations. An expansion cohort (Cohort III) of patients with cholangiocarcinoma or gallbladder carcinoma was treated at the MTD.. A standard 3 + 3 design dose escalation was used. Everolimus was given on Monday/Wednesday/Friday or daily depending upon the dose level. Gemcitabine and cisplatin were administered on days 1 and 8 of each 21 day cycle.. Twelve patients were entered in Cohort I and 15 in Cohort II. The MTD for Cohort I was everolimus 5 mg on Monday/Wednesday/Friday and gemcitabine 800 mg/m(2). For Cohort II, it was everolimus 5 mg on Monday/Wednesday/Friday, gemcitabine 600 mg/m(2), and cisplatin 12.5 mg/m(2). All DLTs in this study were hematologic. Complete responses (CR) were seen in a patient with primary peritoneal carcinoma and another with recurrent pancreatic cancer. Partial responses (PR) were seen in 3 patients: breast, ampullary carcinoma and pheochromocytoma. Of 10 patients enrolled in Cohort III, six patients had stable disease and 4 had progressive disease.. This Phase I clinical trial has demonstrated that these 2-drug and 3-drug combinations are generally well tolerated and safely administered. The main DLTs in both regimens were hematologic, specifically thrombocytopenia. The 3-drug combination can be considered as a platform for future studies in specific tumor types.

Topics: Adult; Aged; Aged, 80 and over; Antimetabolites, Antineoplastic; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; Deoxycytidine; Drug Administration Schedule; Everolimus; Female; Gemcitabine; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Recurrence, Local; Neoplasms; Sirolimus

This phase I study investigated the safety, dose-limiting toxicity, and efficacy in three cohorts all treated with the mTOR inhibitor everolimus that was delivered (1) in combination with 5-fluorouracil with leucovorin (5-FU/LV), (2) with mFOLFOX6 (5-FU/LV + oxaliplatin), and (3) with mFOLFOX6 + panitumumab in patients with refractory solid tumors.. Patients were accrued using a 3-patient cohort design consisting of two sub-trials in which the maximum tolerated combination (MTC) and dose-limiting toxicity (DLT) of everolimus and 5-FU/LV was established in Sub-trial A and of everolimus in combination with mFOLFOX6 and mFOLFOX6 plus panitumumab in Sub-trial B.. Thirty-six patients were evaluable for toxicity, 21 on Sub-trial A and 15 on Sub-trial B. In Sub-trial A, DLT was observed in 1/6 patients enrolled on dose level 1A and 2/3 patients in level 6A. In Sub-trial B, 2/3 patients experienced DLT on level 1B and subsequent patients were enrolled on level 1B-1 without DLT. Three of six patients in cohort 2B-1 experienced grade 3 mucositis, and further study of the combination of everolimus, mFOLFOX6 and panitumumab was aborted. Among the 24 patients enrolled with refractory metastatic colorectal cancer, the median time on treatment was 2.7 months with 45 % of patients remaining on treatment with stable disease for at least 3 months.. While a regimen of everolimus in addition to 5-FU/LV and mFOLFOX6 appears safe and tolerable, the further addition of panitumumab resulted in an unacceptable level of toxicity that cannot be recommended for further study. Further investigation is warranted to better elucidate the role which mTOR inhibitors play in patients with refractory solid tumors, with a specific focus on mCRC as a potential for the combination of this targeted and cytotoxic therapy in future studies.

Topics: Antibodies, Monoclonal; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cohort Studies; Colorectal Neoplasms; Dose-Response Relationship, Drug; Drug Monitoring; Early Termination of Clinical Trials; Everolimus; Female; Fluorouracil; Humans; Leucovorin; Male; Middle Aged; Mucositis; Neoplasm Metastasis; Neoplasms; Organoplatinum Compounds; Oxaliplatin; Panitumumab; Protein Kinase Inhibitors; Severity of Illness Index; Sirolimus; TOR Serine-Threonine Kinases

This study aimed to determine the maximum-tolerated dose and dose-limiting toxicities of pegylated liposomal doxorubicin (PLD) in combination with temsirolimus (T) in patients with refractory solid tumors. Using a standard "3+3" dose escalation design, 23 patients were enrolled in three dosing cohorts in this phase I study. The starting dose level was PLD at 30 mg/m(2) every 4 weeks and T at 20 mg weekly. Pharmacokinetics (PK) of doxorubicin were evaluated for patients in the expansion cohort. The most common treatment-related adverse events of all grades were mucositis/stomatitis (69.6%), anorexia (52.2%), thrombocytopenia (52.2%), and fatigue (47.8%). The recommended doses of this combination for phase II studies are 25 mg/m(2) PLD and 25 mg T. PK analyses suggested increased exposure of doxorubicin in this combination regimen compared to doxorubicin administered as a single agent, possibly due to PK drug interactions. Out of 18 patients evaluable for a treatment response, two had partial responses (PR) (breast cancer and hepatocellular carcinoma) and six had stable disease (SD). Two patients remained on treatment for more than 1 year. The combination of PLD and T is tolerable, and the treatment resulted in clinical benefit. The combination regimen should be further explored in appropriate tumor types.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Cohort Studies; Doxorubicin; Drug Resistance, Neoplasm; Female; Follow-Up Studies; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Polyethylene Glycols; Prognosis; Safety; Sirolimus; Tissue Distribution

The combination of temsirolimus (TEM), an MTOR inhibitor, and hydroxychloroquine (HCQ), an autophagy inhibitor, augments cell death in preclinical models. This phase 1 dose-escalation study evaluated the maximum tolerated dose (MTD), safety, preliminary activity, pharmacokinetics, and pharmacodynamics of HCQ in combination with TEM in cancer patients. In the dose escalation portion, 27 patients with advanced solid malignancies were enrolled, followed by a cohort expansion at the top dose level in 12 patients with metastatic melanoma. The combination of HCQ and TEM was well tolerated, and grade 3 or 4 toxicity was limited to anorexia (7%), fatigue (7%), and nausea (7%). An MTD was not reached for HCQ, and the recommended phase II dose was HCQ 600 mg twice daily in combination with TEM 25 mg weekly. Other common grade 1 or 2 toxicities included fatigue, anorexia, nausea, stomatitis, rash, and weight loss. No responses were observed; however, 14/21 (67%) patients in the dose escalation and 14/19 (74%) patients with melanoma achieved stable disease. The median progression-free survival in 13 melanoma patients treated with HCQ 1200mg/d in combination with TEM was 3.5 mo. Novel 18-fluorodeoxyglucose positron emission tomography (FDG-PET) measurements predicted clinical outcome and provided further evidence that the addition of HCQ to TEM produced metabolic stress on tumors in patients that experienced clinical benefit. Pharmacodynamic evidence of autophagy inhibition was evident in serial PBMC and tumor biopsies only in patients treated with 1200 mg daily HCQ. This study indicates that TEM and HCQ is safe and tolerable, modulates autophagy in patients, and has significant antitumor activity. Further studies combining MTOR and autophagy inhibitors in cancer patients are warranted.

Topics: Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Autophagy; Dose-Response Relationship, Drug; Female; Fluorodeoxyglucose F18; Humans; Hydroxychloroquine; Male; Melanoma; Middle Aged; Neoplasm Staging; Neoplasms; Positron-Emission Tomography; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Vacuoles

We conducted a phase I study in patients with advanced solid tumours to identify the recommended dose, assess pharmacokinetics (PK), pharmacodynamic activity and preclinical antitumour efficacy of the combination of sirolimus and gemcitabine.. Nineteen patients were treated with sirolimus 2 or 5 mg daily and gemcitabine 800 or 1000 mg m(-2) on days 1 and 8. Dose escalation depended on dose-limiting toxicity (DLT) rate during the first 3-week period. Paired skin biopsies were evaluated for phosphorylated S6 (pS6) as marker of mTOR (mammalian target of rapamycin) inhibition. Pharmacokinetics and preclinical evaluation of efficacy using two different sarcoma cell lines and leiomyosarcoma xenografts were also conducted.. Three DLTs were observed: grade 3 transaminitis, grade 3 thrombocytopenia and grade 4 thrombocytopenia. Common treatment-related adverse events included anaemia, neutropenia, thrombocytopenia and transaminitis. Pharmacodynamic analyses demonstrated mTOR inhibition with sirolimus 5 mg and PK showed no influence of sirolimus concentrations on gemcitabine clearance. In vitro and in vivo studies suggested mTOR pathway hyperactivation by gemcitabine that was reversed by sirolimus. Tumour growth in leiomyosarcoma xenografts was dramatically inhibited by the treatment.. Recommended dose was sirolimus 5 mg per 24 h plus gemcitabine 800 mg m(-2). Antitumour activity in preclinical sarcoma models and mTOR signalling inhibition were observed. A phase II study is currently ongoing.

Topics: Adult; Aged; Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Deoxycytidine; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Female; Gemcitabine; Humans; Male; Mice, Inbred BALB C; Mice, Nude; Middle Aged; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

De novo malignancies are a main cause for late death after liver transplantation (LT). Everolimus (ERL) is an immunosuppressive agent with antitumoral properties. The aim of the present retrospective study was to identify prognostic factors, including conversion to ERL, for patients presenting non-cutaneous de novo solid organ malignancy after LT for alcoholic cirrhosis. The study population consisted of 83 patients (presenting 100 tumors, including 75% of upper aerodigestive tract cancers), among the 398 patients who underwent LT for alcoholic cirrhosis in our center. After diagnosis, ERL was introduced in 38 patients and calcineurin-inhibitor was discontinued in 64.1% of them. Tumor stage was a significant prognostic factor with a one-yr survival at 82.6% for early stages, 63.4% for intermediate stages (N+) and 27.4% for disseminated diseases (p < 0.001). Associated relative risk factor was 2.202 (95% CI 1.044-4.644) for intermediate stages and 5.743 (95% CI 2.436-13.541) for metastatic stages. One- and five-yr survival was 77.4% and 35.2% in ERL group vs. 47.2% and 19.4% in the non-ERL group, respectively (p = 0.003). The relative risk factor for ERL was 0.447 (95%CI 0.257-0.778). Our results strongly suggest that conversion to ERL improves the prognosis of de novo malignancies after LT for alcoholic cirrhosis. Prospective studies are needed to confirm this benefit.

Topics: Adult; Aged; Everolimus; Female; Follow-Up Studies; Humans; Immunosuppressive Agents; Liver Cirrhosis, Alcoholic; Liver Transplantation; Male; Middle Aged; Neoplasms; Postoperative Complications; Prognosis; Retrospective Studies; Risk Factors; Sirolimus; Survival Rate

Two strategies to interrogate the insulin growth factor 1 receptor (IGF-1R) pathway were investigated: vertical inhibition with dalotuzumab and MK-2206 or ridaforolimus to potentiate PI3K pathway targeting and horizontal cross-talk inhibition with dalotuzumab and MK-0752 to exert effects against cellular proliferation, angiogenesis, and stem cell propagation.. A phase I, multi-cohort dose escalation study was conducted in patients with advanced solid tumours. Patients received dalotuzumab (10 mg kg(-1)) and escalating doses of MK-2206 (90-200 mg) or escalating doses of dalotuzumab (7.5-10 mg kg(-1)) and MK-0752 (1800 mg) weekly. Upon maximum tolerated dose determination, patients with low-RAS signature, high-IGF1 expression ovarian cancer were randomised to dalotuzumab/MK-2206 versus dalotuzumab/ridaforolimus, whereas patients with high IGF1/low IGF2 expression colorectal cancer received dalotuzumab/MK-0752.. A total of 47 patients were enrolled: 29 in part A (18 in the dalotuzumab/MK-2206 arm and 11 in the dalotuzumab/MK-0752 arm) and 18 in part B (6 in each arm). Dose-limiting toxicities (DLTs) for dalotuzumab/MK-2206 included grade 4 neutropenia and grade 3 serum sickness-like reaction, maculopapular rash, and gastrointestinal inflammation. For dalotuzumab/MK-0752, DLTs included grade 3 dehydration, rash, and diarrhoea. Seven patients remained on study for >4 cycles.. Dalotuzumab/MK-2206 and dalotuzumab/MK-0752 combinations were tolerable. Further developments of prospectively validated predictive biomarkers to aid in patient selection for anti-IGF-1R therapies are needed.

Topics: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Benzene Derivatives; Biomarkers, Tumor; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Cohort Studies; Female; Follow-Up Studies; Heterocyclic Compounds, 3-Ring; Humans; Male; Middle Aged; Neoplasm Staging; Neoplasms; Prognosis; Propionates; Proto-Oncogene Proteins c-akt; Randomized Controlled Trials as Topic; Receptor, IGF Type 1; Receptors, Notch; Sirolimus; Sulfones; Tissue Distribution; TOR Serine-Threonine Kinases

To determine the maximal tolerated dose (MTD) of the combination of weekly temsirolimus and every other week vinorelbine in patients with advanced or refractory solid tumors.. Patients were treated with intravenous temsirolimus on days 1, 8, 15, and 22 and intravenous vinorelbine on days 1 and 15. Cycles were repeated every 28 days.. Nineteen patients were enrolled in the study. Tumor types included lung (5), prostate (2), neuroendocrine of pancreas (1), bladder (2), uterus (3), cervix (4), and vagina (2). All patients had received prior chemotherapy. Four patients were enrolled to dose level I, nine to dose level II, and six to dose level III. Six patients were inevaluable and replaced. Fifty-seven total cycles were administered. There was 1 dose-limiting toxicity at level II (grade 3 anorexia/dehydration) and 2 at level III (grade 3 hypokalemia; grade 4 neutropenia). Two patients died at dose level III; one was study-related with grade 4 neutropenia. Grade 3/4 toxicities observed during the first cycle included neutropenia (2), anemia (1), anorexia (1), dehydration (1), hyperglycemia (1), hypertriglyceridemia (1), and hypokalemia (1). Best response included two patients (prostate and non-small cell lung cancer) with partial response and eight patients with stable disease with median duration of best response of 3.2 months.. Temsirolimus 25 mg given days 1, 8, 15, and 22 in combination with vinorelbine 20 mg/m(2) given days 1 and 15 every 4 weeks was found to be the MTD. This dose combination is considered feasible in phase II trials.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Dose-Response Relationship, Drug; Feasibility Studies; Female; Humans; Infusions, Intravenous; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Sirolimus; Treatment Outcome; Vinblastine; Vinorelbine

This phase I dose-escalation study was designed to evaluate the combination of the mammalian target of rapamycin inhibitor ridaforolimus with the vascular endothelial growth factor inhibitor bevacizumab.. Seventeen adult patients with refractory advanced solid tumours received oral ridaforolimus (30 or 40 mg) once daily for 5 days per week (QDx5/wk) combined with intravenous bevacizumab (10 mg/kg every 2 weeks [Q2wk] or 15 mg/kg every 3 weeks [Q3wk]). Patients were evaluated for dose-limiting toxicities, safety and anti-tumour activity.. A 40 mg dose of ridaforolimus with either bevacizumab dosing schedule was the recommended phase II dose. No dose-limiting toxicities were reported; the most common drug-related adverse events were mucosal inflammation and anorexia. Seven patients, with clinical features that included primary tumour of the abdominal origin (colorectal, pancreatic or gynaecological cancers) and previous abdominal radiotherapy, reported serious adverse events related to bowel perforations. There were no objective responses, but 65% of patients had a best response of stable disease.. Oral ridaforolimus (40 mg QDx5/wk) is feasible to combine with standard doses of bevacizumab, although careful patient selection would be needed to mitigate the risk of bowel perforation-related adverse events. Combination therapy produced prolonged stable disease in several heavily pretreated patients.

Topics: Adult; Aged; Angiogenesis Inhibitors; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Cohort Studies; Dose-Response Relationship, Drug; Female; Humans; Male; Middle Aged; Neoplasms; Sirolimus; Treatment Outcome; Young Adult

Ridaforolimus (MK-8669, AP23573) is a potent and selective mammalian target of rapamycin (mTOR) inhibitor. Preclinically, ridaforolimus displays antiproliferative activity against a variety of human tumors in vitro and tumor xenograft models in vivo, with additive or synergistic activity when combined with other anticancer agents. Antitumor activity has been confirmed in adults. This phase I study determined the safety, pharmacological, biologic, and toxicity profiles of ridaforolimus in pediatric patients with refractory malignancies.. Eligible children ages 1 to 18 years with advanced solid tumors were enrolled in a 3 + 3 dose escalation design, to determine the safety, tolerability, and maximum tolerated dose (MTD)/dose-limiting toxicity (DLT) of ridaforolimus. Toxicities, pharmacokinetics, and pharmacodynamics were characterized.. Fifteen patients were treated. No DLT was observed at any dose level tested; therefore, an MTD was not identified. Most adverse events were mild to moderate; the most common grades 3 and 4 adverse events were hematologic, including thrombocytopenia and anemia. Nonhematologic adverse events were mostly electrolyte disturbances. The observed pharmacokinetic profile of ridaforolimus in children was consistent with that previously showed in adults. Pharmacodynamic confirms that the dose range tested has pharmacological/pharmacodynamic activity. Forty percent of patients achieved stable disease including four of six with central nervous system tumors and two of eight with sarcomas.. This first-in-pediatrics study shows that the second-generation mTOR inhibitor ridaforolimus is well tolerated in heavily pretreated children with refractory solid tumors. No DLTs were observed over the dose range tested. Ridaforolimus may represent a therapeutic option for use in pediatric malignancies.

Topics: Adolescent; Antineoplastic Agents; Child; Child, Preschool; Female; Humans; Male; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Inhibition of either vascular endothelial growth factor receptor or mammalian target of rapamycin (mTOR) signaling improves outcomes in patients with several advanced solid tumors. We conducted a phase I trial of temsirolimus with pazopanib to investigate the feasibility of simultaneous 'vertical inhibition' of vascular endothelial growth factor receptor and mTOR pathways. Patients with advanced solid tumors, no previous pazopanib or mTOR inhibitor, good performance status, and acceptable end-organ function were eligible. In a typical 3+3 escalation design starting at temsirolimus 15 mg by an intravenous infusion weekly and pazopanib 400 mg orally daily, we defined dose-limiting toxicity (DLT) as attributable grade 3 or higher nonhematologic adverse events in the first 28-day cycle and the maximum tolerable dose as the maximum dose level at which less than two patients experienced DLT. At the initial dose level, two patients had four DLTs (anorexia, fatigue, hyponatremia, and hypophosphatemia). After reduction to temsirolimus 10 mg intravenous infusion weekly and pazopanib 200 mg orally daily, one of three patients had DLT (fatigue) and the first patient in the subsequent expansion had dose-limiting hypophosphatemia. Attributable grade 3 or higher adverse events in more than one patient included leukopenia, neutropenia, fatigue, and hypophosphatemia. Tumor reduction not fulfilling the RECIST criteria for partial response was the best response in four of seven evaluable patients. The combination of temsirolimus and pazopanib was not feasible at clinically meaningful doses in this population because of constitutional and electrolyte disturbances.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Dose-Response Relationship, Drug; Female; Humans; Indazoles; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Staging; Neoplasms; Pyrimidines; Receptors, Vascular Endothelial Growth Factor; Sirolimus; Sulfonamides; TOR Serine-Threonine Kinases

Ridaforolimus (AP23573, MK-8669 or deforolimus) is an inhibitor of mammalian target of rapamycin (mTOR), an important regulator in the cell survival pathway. This open-label, single center phase I study aimed to investigate the pharmacokinetic (PK) and safety profiles of ridaforolimus in Chinese patients with treatment-refractory advanced or relapsed solid tumors. The PK data generated from these Chinese patients were further compared with those previously reported in Caucasian and Japanese patient populations.. The patients were given an oral dose of 40 mg of ridaforolimus on Day 1 of the study. On Day 8, patients were initiated on a treatment regimen that comprised a once daily dose of 40 mg of ridaforolimus for five consecutive days, followed by a 2-day off-drug interval. Patients repeated this regimen until disease progression or intolerance. Blood samples were collected at specific times pre- and post-treatment to establish the PK profile of ridaforolimus in all patients.. Fifteen patients were given at least one dose of 40 mg of ridaforolimus. The median absorption lag-time was 2 hours, the median Tmax was 4 hours and the mean elimination half-life was 53 hours. The accumulation ratio for AUC(0-24hr) was 1.3 on day 19 (steady state)/day 1 (after a single dose). The most common drug-related adverse events (AEs) that occurred in ≥40% of patients were stomatitis, proteinuria, leukopenia, hyperglycemia, and pyrexia. Grade 3/4 drug-related AEs were anemia, stomatitis, fatigue, thrombocytopenia, constipation, gamma glutamyltransferase increase, and proteinuria. All 11 evaluable patients achieved stable disease.. Oral ridaforolimus at a daily dose of 40 mg were generally well tolerated in Chinese patients with advanced or refractory solid tumors. Adverse events and PK profiles of ridaforolimus in this study were similar to those from Caucasian and Japanese patients reported previously.

Topics: Adult; Aged; Drug Administration Schedule; Female; Humans; Male; Middle Aged; Neoplasms; Sirolimus

To determine the recommended phase II dose (RP2D) and assess the safety, pharmacokinetics (PKs) and pharmacodynamics of RO4929097in combination with temsirolimus.. Escalating doses of RO4929097 and temsirolimus were administered at three dose levels. Patients received once daily oral RO4929097 on a 3 days on/4 days off schedule every week, and weekly intravenous temsirolimus. Blood samples were collected for PK analysis. Archival tissue specimens were collected for Notch pathway biomarker analysis and genotyping of frequent oncogenic mutations.. Seventeen patients with refractory advanced solid tumors were enrolled in three dose levels (DLs): DL1 (RO4929097 10 mg; Temsirolimus 25 mg), DL2 (RO4929097 20 mg; Temsirolimus 25 mg), and DL3 (RO4929097 20 mg; Temsirolimus 37.5 mg). The most common toxicities related to the study drug combination included: fatigue (82 %; grade 3 6 %), mucositis, (71 %; grade 3 6 %), neutropenia (59 %; grade 3 12 %), anemia (59 %; grade 3 0 %), and hypertriglyceridemia (59 %; grade 3 0 %). Two dose-limiting toxicities, grade 3 rash and grade 3 mucositis, were observed in the same patient in the first dose level prompting dose expansion. Eleven patients (73 %) had stable disease as their best response. Co-administration of RO4929097 was associated with increased clearance and reduced exposure to temsirolimus, suggestive of drug-drug interaction via CYP3A4 induction. No correlation between the expression of Notch pathway biomarkers or genotype and time to progression was noted.. RO4929097 can be safely combined with temsirolimus in patients with advanced solid tumors. The RP2D was established at 20 mg of RO4929097 combined with 37.5 mg of temsirolimus.

Topics: Adult; Aged; Aged, 80 and over; Amyloid Precursor Protein Secretases; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzazepines; Calcium-Binding Proteins; Fatigue; Female; Humans; Intercellular Signaling Peptides and Proteins; Male; Membrane Proteins; Middle Aged; Mucositis; Neoplasms; Protein Kinase Inhibitors; Receptor, Notch3; Receptors, Notch; Serrate-Jagged Proteins; Sirolimus

Lenalidomide, an immunomodulatory and anti-angiogenic drug, and temsirolimus, an mTOR inhibitor, have synergistic anti-cancer effects in preclinical models. We conducted a phase I study of the combination in patients with advanced cancers.. A "3 + 3" study design was used. During the escalation phase, lenalidomide (orally, days 1-21) and temsirolimus (intravenously, once a week) were given at the following respective doses: level 1 (10 mg, 15 mg); level 2 (10 mg, 20 mg); level 3 (20 mg, 20 mg); and level 4 (20 mg, 25 mg) (1 cycle = 28 days). The maximum tolerated dose, dose-limiting toxicity, and response were assessed.. Forty-three patients were treated (median age: 58 years (range, 21-80); male/female: 26/17). The most common diagnoses were colorectal cancer (N = 5), sarcoma (N = 5), neuroendocrine carcinoma (N = 4) and adenoid cystic carcinoma (N = 4). Overall, 121 cycles (median: 2) were administered. No dose-limiting toxicities were observed. The maximum tested dose (dose level 4) was used in the expansion phase. Grade 3-4 treatment-related hematologic toxicities (all reversible) were seen in 19 (72%) patients and included neutropenia (N = 12), thrombocytopenia (N = 6), and infection (N = 1). Grade 3 hyperglycemia and Grade 3 hypertriglyceridemia were noted in 21% and 20% of patients, respectively. Of 43 patients, 30 (70%) received prophylactic anticoagulation. There were no thrombotic events. Response was evaluable in 40 patients: one (2.5%) patient had a partial response and 19 (48%) had stable disease (SD), with SD ≥ 6 months in 6 (15%) patients. Tumor types with SD ≥ 6 months were soft tissue sarcoma (2/5; 40%), adenoid cystic carcinoma (1/4; 25%), parotid adenocarcinoma (1/2; 50%), adrenocortical carcinoma (1/3; 33%), and neuroendocrine carcinoma (1/4; 25%). The median progression-free survival duration was 2.2 months (95% CI, 1.5-2.9), and the median overall survival duration was 7.8 months (95% CI, 5.1-10.6).. Lenalidomide and temsirolimus combination therapy was well tolerated and associated with clinical benefit in patients with soft tissue sarcoma, adenoid cystic carcinoma, neuroendocrine carcinoma, parotid carcinoma, and adrenocortical carcinoma.

Topics: Adult; Aged; Aged, 80 and over; Angiogenesis Inhibitors; Antineoplastic Combined Chemotherapy Protocols; Drug Administration Schedule; Female; Humans; Lenalidomide; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Sirolimus; Thalidomide; TOR Serine-Threonine Kinases; Young Adult

Everolimus, an oral inhibitor of mammalian target of rapamycin, can augment the efficacy of HER inhibitors in preclinical studies. This study was conducted to determine the safety and pharmacokinetics (PK) of the combination of lapatinib, a Her1 and 2 inhibitor, and everolimus and to describe its anti-tumor activity in the Phase I setting.. In Part I, dose escalation to define the maximum tolerated dose (MTD) was performed. In Part II, PK of both drugs were analyzed to assess drug-drug interaction.. Twenty-three evaluable patients with advanced cancers were treated on six different dose levels in Part I of the study. The dose-limiting toxicities were diarrhea, rash, mucositis, and fatigue. The MTD of the combination was 1,250 mg of lapatinib and 5 mg of everolimus once daily. In Part II of the study, 54 patients were treated with the combination at the MTD. The mean everolimus time to maximum concentration was increased by 44 %, and mean clearance was decreased by 25 % when co-administered with lapatinib, though these differences were not statistically significant. There was no significant influence on the PK of lapatinib by everolimus. Two patients achieved a partial response [thymic cancer (45+ months) and breast cancer (unconfirmed PR; 7 months)]; 11 patients attained stable disease of at least 4 months.. Lapatinib and everolimus are well tolerated at doses of 1,250 and 5 mg po daily, respectively. Stable disease ≥4 months/PR was achieved in 13 of 78 patients (17 %).

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cohort Studies; Dose-Response Relationship, Drug; Drug Interactions; ErbB Receptors; Everolimus; Female; Humans; Incidence; Lapatinib; Male; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Quinazolines; Receptor, ErbB-2; Sirolimus; TOR Serine-Threonine Kinases; United States; Young Adult

This dose-finding phase I study investigated the maximum-tolerated dose (MTD) and safety of weekly nanoparticle albumin-bound rapamycin (nab-rapamycin) in patients with untreatable advanced nonhematologic malignancies.. nab-Rapamycin was administered weekly for 3 weeks followed by 1 week of rest, with a starting dose of 45 mg/m(2). Additional doses were 56.25, 100, 150, and 125 mg/m(2).. Of 27 enrolled patients, 26 were treated. Two dose-limiting toxicities (DLT) occurred at 150 mg/m(2) [grade 3 aspartate aminotransferase (AST) elevation and grade 4 thrombocytopenia], and two DLTs occurred at 125 mg/m(2) (grade 3 suicidal ideation and grade 3 hypophosphatemia). Thus, the MTD was declared at 100 mg/m(2). Most treatment-related adverse events (TRAE) were grade 1/2, including thrombocytopenia (58%), hypokalemia (23%), mucositis (38%), fatigue (27%), rash (23%), diarrhea (23%), nausea (19%), anemia (19%), hypophosphatemia (19%), neutropenia (15%), and hypertriglyceridemia (15%). Only one grade 3 nonhematologic TRAE (dyspnea) and one grade 3 hematologic event (anemia) occurred at the MTD. One patient with kidney cancer had a partial response and 2 patients remained on study for 365 days (patient with mesothelioma) and 238 days (patient with neuroendocrine tumor). The peak concentration (Cmax) and area under the concentration-time curve (AUC) of rapamycin increased with dose between 45 and 150 mg/m(2), except for a relatively low AUC at 125 mg/m(2). nab-Rapamycin significantly inhibited mTOR targets S6K and 4EBP1.. The clinical dose of single-agent nab-rapamycin was established at 100 mg/m(2) weekly (3 of 4 weeks) given intravenously, which was well tolerated with preliminary evidence of response and stable disease, and produced a fairly dose-proportional pharmacokinetic profile in patients with unresectable advanced nonhematologic malignancies.

Topics: Adolescent; Adult; Aged; Antibiotics, Antineoplastic; Drug Administration Schedule; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Staging; Neoplasms; Sirolimus; Treatment Outcome; Young Adult

Ridaforolimus is an inhibitor of mTOR with evidence of antitumor activity in an I.V. formulation. This multicenter, open-label, 3 + 3 design nonrandomized, dose-escalation, phase I/IIa trial was conducted to determine the safety, pharmacokinetic (PK) and pharmacodynamic parameters, maximum tolerated dose, and antitumor activity of oral ridaforolimus.. Patients with metastatic or unresectable solid tumors refractory to therapy were eligible. Seven different continuous and intermittent dosing regimens were examined.. One hundred and forty-seven patients were enrolled in this study among which 85 were patients with sarcoma. Stomatitis was the most common DLT observed. The dosing regimen, 40 mg QD × 5 days/week, provided the best combination of cumulative dose, dose density, and cumulative exposure, and was the recommended dosing regimen for subsequent clinical development. PK was nonlinear, with less than proportional increases in day-1 blood AUC0-∞ and Cmax, particularly with doses >40 mg. The terminal half-life estimate of ridaforolimus (QD × 5 40 mg) was 42.0 h, and the mean half-life ∼30-60 h. The clinical benefit rate, (complete response, partial response, or stable disease for ≥4 months was 24.5% for all patients and 27.1% for patients with sarcoma.. Oral ridaforolimus had an acceptable safety profile and exhibited antitumor activity in patients with sarcoma and other malignancies. ClinicalTrials.gov Identifier NCT00112372.

Topics: Adult; Aged; Aged, 80 and over; Animals; Drug Administration Schedule; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Staging; Neoplasms; Sarcoma; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

A pediatric study has established a maximum tolerated dose (MTD) for temsirolimus (Tem) of more than 150 mg/m intravenously/week. A phase I trial was conducted to establish the MTD for Tem in combination with valproic acid (VPA) in children and adolescents with refractory solid tumors. The secondary aims included expression of mammalian target of rapamycin (mTOR) markers on archival tumor tissue; Tem pharmacokinetics; assessment of histone acetylation (HA); and tumor response. Patients were treated with VPA (5 mg/kg orally three times daily) with a target serum level of 75-100 mcg/ml. Tem was started at an initial dose of 60 mg/m/week. Pharmacokinetics and HA measurements were performed during weeks 1 and 5. Two of the first three patients experienced dose-limiting toxicity (grade 3 mucositis). Tem at 35 mg/m/week was found to be tolerable. Peak Tem concentrations were higher in all patients compared with those in previously published reports of single agent Tem. Increases in HA are correlated with VPA levels. All tumor samples expressed mTORC1 and mTORC2. An objective response was observed in one patient (melanoma), whereas transient stable disease was observed in four other patients (spinal cord ependymoma, alveolar soft part sarcoma, medullary thyroid carcinoma, and hepatocellular carcinoma). The MTD of Tem when administered with VPA is considerably lower than when used as a single agent, with mucositis the major dose-limiting toxicity. The combination merits further study and may have activity in melanoma. Attention to drug-drug interactions will be important in future multiagent trials including Tem.

Topics: Adolescent; Antineoplastic Combined Chemotherapy Protocols; Child; Child, Preschool; Diphenhydramine; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Eruptions; Early Termination of Clinical Trials; Fatigue; Female; Hematologic Diseases; Histone Deacetylase Inhibitors; Humans; Infusions, Intravenous; Male; Mucositis; Neoplasms; Pain; Sirolimus; Valproic Acid

The purpose of this phase I trial was to establish the maximum tolerated dose and define the dose-limiting toxicities of a combination of temsirolimus and metformin. Patients with advanced solid tumours who had exhausted standard treatment options were eligible. Treatment included weekly intravenous temsirolimus and daily oral metformin. Eleven patients were enrolled. Dose-limiting toxicities were observed in all patients at the initial dose level of 25 mg weekly of temsirolimus and metformin 500 mg po BID. At dose level -1, 2 of 8 patients experienced dose-limiting toxicities. Toxicities included grade 4 pneumonitis, persistent grade 3 fatigue, and thrombocytopenia requiring dose delays. The maximum tolerated dose (level -1) was 20 mg temsirolimus weekly and 500 mg po daily of metformin. One patient with head and neck cancer experienced a partial response. Five patients had stable disease including a patient with melanoma who had stable disease for 22 months.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Drug Administration Schedule; Female; Humans; Infusions, Intravenous; Male; Maximum Tolerated Dose; Metformin; Middle Aged; Neoplasms; Ontario; Pilot Projects; Protein Kinase Inhibitors; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Treatment Outcome; Young Adult

The purpose of the study was to assess the safety, tolerability, recommended phase II dose (RPTD), and preliminary antitumor activity of the combination of carboplatin-paclitaxel (Taxol)-temsirolimus.. Patients with solid malignancies suitable for carboplatin-paclitaxel (CP) chemotherapy and two or less prior lines of chemotherapy received 15, 20, or 25 mg of temsirolimus per week with CP given every 21 days. Thirty-eight eligible patients were entered into six dose levels with the first two levels administering temsirolimus on days 8 and 15 and the subsequent four dose levels switching to days 1 and 8 temsirolimus administration.. Days 8 and 15 administration of temsirolimus was not feasible due to myelosuppression on day 15. CP on day 1 with temsirolimus on days 1 and 8 was well tolerated. Dose-limiting toxicity (DLT) was grade 4 thrombocytopenia (n=2) and grade 3 fatigue (n=1). Relative dose intensities for carboplatin, paclitaxel, and temsirolimus at the RPTD were 92%, 82%, and 56%, respectively. Non-DLT treatment-related adverse events occurring in >20% of patients included fatigue, mucositis, alopecia, neuropathy, nausea, neutropenia, thrombocytopenia, and infection. Grade 3/4 non-hematological toxicity was rare. Partial responses (PRs) and disease stabilization were seen in 46% and 49% of patients, respectively. Nine of 11 (82%) endometrial cancer patients had objective PRs.. Carboplatin-paclitaxel-temsirolimus is well tolerated and the RPTD is carboplatin area under the curve 5 mg/ml/min, paclitaxel 175 mg/m2, both given on day 1 with temsirolimus 25 mg on days 1 and 8.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Carboplatin; Dose-Response Relationship, Drug; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Paclitaxel; Sirolimus

Everolimus is an oral mTOR-inhibitor. Preclinical data show synergistic effects of mTOR inhibition in combination with 5-fluorouracil-based anticancer therapy. The combination of everolimus with capecitabine seems therefore an attractive new, orally available, treatment regimen.. Safety, preliminary efficacy and pharmacokinetics of everolimus in combination with capecitabine were investigated in patients with advanced solid malignancies. Patients were treated with fixed dose everolimus 10 mg/day continuously, plus capecitabine bid for 14 days in three-weekly cycles. Dose escalation of capecitabine proceeded according to the standard 3 × 3 phase I design in four predefined dose levels (500-1,000 mg/m(2) bid).. In total, 18 patients were enrolled. Median (range) treatment duration with everolimus was 70 days (21-414). Capecitabine 1,000 mg/m(2) bid combined with 10 mg/day everolimus was declared the maximum tolerated dose, at which level one patient developed dose-limiting toxicity (stomatitis grade 3). Drug-related adverse events were mostly grade ≤ 2 and included mainly fatigue (56%), stomatitis (50%), and hand-foot syndrome (33%). Partial response was documented in three patients, and four had stable disease. There was no pharmacokinetic interaction between everolimus and capecitabine.. Everolimus 10 mg/day continuously combined with capecitabine 1,000 mg/m(2) bid for 14 days every 3 weeks is a patient-convenient, safe and tolerable oral treatment regimen. This is the first study to demonstrate feasibility of this combination at doses with proven single agent efficacy in a number of tumors. Prolonged clinical benefit was observed in an encouraging 39% of patients with advanced solid malignancies.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; Capecitabine; Deoxycytidine; Dose-Response Relationship, Drug; Everolimus; Female; Fluorouracil; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Staging; Neoplasms; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases; Young Adult

Purpose Activation of EGFR can stimulate proliferative and survival signaling through mTOR. Preclinical data demonstrates synergistic activity of combined EGFR and mTOR inhibition. We undertook a phase I trial of temsirolimus (T, an mTOR inhibitor) and EKB-569 (E, an EGFR inhibitor) to determine the safety and tolerability. Methods The primary aim was to determine the maximally tolerated dose (MTD) of this combination in adults with solid tumors. Following the dose-escalation phase, (Cohort A), two subsequent cohorts were used to assess any pharmacokinetic (PK) interaction between the agents. Results Forty eight patients were enrolled. The MTD of this combination was E, 35 mg daily and T, 30 mg on days 1-3 and 15-17 using a 28-day cycle. The most common toxicities were nausea, diarrhea, fatigue, anorexia, stomatitis, rash, anemia, neutropenia, thrombocytopenia, and hypertriglyceridemia. Sixteen patients (36%) had at least one grade 3 toxicity. The most frequent grade 3/4 toxicities were diarrhea, dehydration, and nausea and vomiting (19% each). No grade 5 events were seen. Four patients had a partial response and 15 had stable disease. Clinical benefit was seen across a range of tumor types and in all cohorts. PK analysis revealed no significant interaction between E and T. Conclusions This combination of agents is associated with tolerable toxicities at doses that induced responses. PK studies revealed no interaction between the drugs. Further investigations of this targeting strategy may be attractive in renal cell carcinoma, non-small cell lung cancer, alveolar sarcoma, and carcinoid tumor.

Topics: Adult; Aged; Aged, 80 and over; Aminoquinolines; Aniline Compounds; Antineoplastic Combined Chemotherapy Protocols; Cohort Studies; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Synergism; ErbB Receptors; Female; Follow-Up Studies; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Young Adult

Preclinical studies demonstrate synergistic anti-tumor activity with the combination of everolimus and cisplatin. We conducted a phase I study to establish the recommended phase II of oral everolimus to be given with low-dose weekly intravenous cisplatin.. Part A used a standard 3 + 3 dose escalation scheme. There were 4 planned dose levels of everolimus: 2.5, 5, 7.5, and 10 mg/day. Subjects received oral everolimus during days 1-21 and cisplatin 20 mg/m(2) intravenously (fixed dose) on days 1, 8, and 15 of a 28-day cycle. Pharmacokinetic (PK) blood samples were collected on day 1 and day 8 of cycle 1 in Part A. After the phase II recommended dose was established (Part A), 6 additional subjects were enrolled in an expansion cohort (Part B). Response was assessed by RECIST q 2 cycles for all subjects.. Thirty patients were enrolled (18 male, 12 female) and 29 were treated. Median age was 61 years (31-79) and the median number of prior cytotoxic chemotherapy regimens was 2 (0-3). Eighty-three percent of subjects had received prior RT. DLTs occurred at dose level 1 (sudden death of unclear cause in a patient with melanoma metastatic to liver) and dose level 2 (bowel obstruction). No DLTs occurred at dose levels 3 and 4. The most common adverse events (≥grade 3) among 28 patients evaluable for toxicity were lymphopenia (36%), hyperglycemia (11%), fatigue (11%), and venous thrombosis (11%). PK analysis of everolimus demonstrated dose-proportional increases in C (max) (mean 91.9 ng/ml) and AUC(0-INF) (mean 680.5 h*ng/ml) at dose level 4. Three partial responses were seen (metastatic pulmonary carcinoid, n = 2; metastatic sinus carcinoma, n = 1). Prolonged stable disease ≥6 cycles occurred in subjects with pulmonary carcinoid, oropharyngeal squamous cell carcinoma, basal cell carcinoma, papillary thyroid carcinoma, and esthesioneuroblastoma (n = 1 each).. The phase II recommended dose is everolimus 10 mg/day (days 1-21) + cisplatin 20 mg/m(2) (days 1, 8, and 15) of a 28-day cycle. PK data demonstrate dose-proportional increases in exposure, as previously described for everolimus monotherapy. Anti-tumor activity was observed in several tumor types.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; Dose-Response Relationship, Drug; Drug Administration Schedule; Everolimus; Female; Humans; Injections, Intravenous; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Invasiveness; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Ridaforolimus is a non-prodrug mTOR inhibitor. The safety, pharmacokinetics (PK), and antitumor activity of oral ridaforolimus were assessed in Japanese patients with refractory solid tumors.. Ridaforolimus (20 or 40 mg) was administered as a single dose on Day 1, followed by once daily dosing five times a week for a 3-week cycle beginning on Day 8. Full PK sampling was performed on Days 1 and 26.. Thirteen patients (7 at 20 mg and 6 at 40 mg) were enrolled. The median treatment duration was 82 days. The most common drug-related adverse events were stomatitis, hypertriglyceridemia, and proteinuria. Two patients had dose-limiting toxicities (grade 3 stomatitis at 20 mg, and grade 3 anorexia and vomiting at 40 mg). Four patients had grade 1 interstitial pneumonitis. Ridaforolimus in the whole blood was rapidly absorbed and slowly eliminated with a half-life of approximately 56-58 h after a single dose. Two patients (with non-small cell lung cancer and angiosarcoma, respectively) achieved a partial response, and five patients (one with thymic cancer and four with soft tissue sarcomas) had a stable disease for ≥ 16 weeks.. Ridaforolimus was well tolerated up to a dose of 40 mg in Japanese patients. Preliminary evidence of antitumor activity was observed for patients with solid tumors. Further investigation at this dose is warranted.

Topics: Adult; Aged; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Japan; Male; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases

As part of a phase 1 dose-escalation trial, the pharmacodynamic activity of the mammalian target of rapamycin (mTOR) inhibitor ridaforolimus was assessed in multiple tissues by measuring levels of phosphorylated 4E binding protein-1 (p-4E-BP1) or S6, two downstream markers of mTOR activity.. 32 patients (pts) were dosed intravenously with ridaforolimus once daily for 5 consecutive days (QD × 5) every 2 weeks. The pharmacodynamic activity of ridaforolimus was assessed in peripheral blood mononuclear cells (PBMCs; 32 pts), skin (28 pts), and tumor specimens (3 pts) collected before and after dosing by measuring levels of p-4E-BP1 by immunoblot analysis or pS6 by immunohistochemistry. Levels of these markers were assessed in up to 19, 5, and 2 pre- and post-dose time points in PBMC, skin, and tumor specimens, respectively.. In preclinical models, ridaforolimus induced a dose-dependent inhibition of p-4E-BP1 in PBMCs that was associated with antitumor activity. Rapid and potent inhibition of mTOR was observed in PBMCs from all 32 pts dosed, with a median level of inhibition of 96% observed within 1 h after the first dose. Inhibition of mTOR (>90%) was sustained during the entire QD × 5 dosing period, and substantial inhibition was still observed after the 9-day holiday between dosing courses. Evidence of mTOR inhibition was also obtained in skin in pts from all dose cohorts, although it did not persist through the break between courses. After two to three doses of ridaforolimus, inhibition of mTOR was detected in the tumor from one of three pts analyzed.. Ridaforolimus was shown to inhibit its intended target, mTOR, in PBMCs, skin, and tumors. In PBMCs and skin, inhibition was observed at all dose levels tested, thus supporting but not driving the selection of a recommended phase 2 dose.

Topics: Adaptor Proteins, Signal Transducing; Animals; Antineoplastic Agents; Cell Cycle Proteins; Cell Line, Tumor; Dose-Response Relationship, Drug; Female; Humans; Leukocytes, Mononuclear; Mice; Mice, SCID; Neoplasms; Phosphoproteins; Phosphorylation; Ribosomal Protein S6; Sirolimus; Skin; Time Factors; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

Preclinical data suggest concurrent inhibition of VEGF, mTOR and EGFR pathways may augment antitumor and antiangiogenic effects compared to inhibition of each pathway alone. This study evaluated the maximum tolerated dose/recommended phase II dose and safety and tolerability of bevacizumab, everolimus and panitumumab drug combination.. Subjects with advanced solid tumors received escalating doses of everolimus and flat dosing of panitumumab at 4.8 mg/kg and bevacizumab at 10 mg/kg every 2 weeks. Dose-limiting toxicities (DLTs) were assessed in cycle 1; toxicity evaluation was closely monitored throughout treatment. Treatment continued until disease progression or undesirable toxicity.. Thirty-two subjects were evaluable for toxicity; 31 subjects were evaluable for tumor response. DLTs were observed in cohorts with everolimus at 10 and 5 mg daily and included grade 3 mucositis, skin rash and thrombocytopenia. Therefore, everolimus was dose-reduced to 5 mg three times weekly, which improved the tolerability of the treatment regimen. Common adverse events were skin rash/pruritus (91 %), mucositis/stomatitis (75 %), hypomagnesemia (72 %), hypocalcemia (56 %) and hypokalemia (50 %). There were 3 partial responses; an additional 10 subjects had stable disease ≥6 months. Three subjects with ovarian cancer and one with endometrial cancer achieved prolonged disease control ranging from 11 to >40 months.. The recommended phase II dose is everolimus at 5 mg three times weekly plus panitumumab at 4.8 mg/kg and bevacizumab at 10 mg/kg every 2 weeks. This dosing regimen has an acceptable safety and tolerability profile and appears to have moderate the clinical activity in refractory tumors.

Topics: Adult; Aged; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Dose-Response Relationship, Drug; Drug Administration Schedule; Everolimus; Exanthema; Female; Humans; Hypocalcemia; Hypokalemia; Male; Middle Aged; Mucositis; Neoplasms; Panitumumab; Sirolimus; Treatment Outcome; Young Adult

To define the maximum tolerated dose, clinical toxicities, and pharmacodynamics of bevacizumab, everolimus, and panobinostat (LBH-589) when administered in combination to patients with advanced solid tumor malignancies.. Subjects received 10 mg of panobinostat three times weekly, 5 or 10 mg everolimus daily, and bevacizumab at 10 mg/kg every 2 weeks. Dose-limiting toxicities (DLTs) were assessed in cycle 1; toxicity evaluation was closely monitored throughout treatment. Treatment continued until disease progression or undesirable toxicity. Protein acetylation was assessed in peripheral blood mononuclear cells (PBMC) both at baseline and on treatment.. Twelve subjects were evaluable for toxicity and nine subjects for response. DLTs in cohort 1 included grade 2 esophagitis and grade 3 oral mucositis; DLTs in cohort -1 were grade 2 ventricular arrhythmia and grade 2 intolerable skin rash. Common adverse events were diarrhea (50 %), headache (33 %), mucositis/stomatitis (25 %), hyperlipidemia (25 %), and thrombocytopenia (25 %). There was 1 partial response; an additional 2 subjects had stable disease as best response. No consistent changes in protein acetylation in PBMC were observed in samples available from eight patients on treatment compared with baseline.. Bevacizumab, everolimus, and panobinostat in combination at the lowest proposed doses did not have an acceptable safety and tolerability profile and did not consistently inhibit HDAC activity; therefore, we do not recommend further evaluation.

Topics: Administration, Oral; Adult; Aged; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Dose-Response Relationship, Drug; Drug Administration Schedule; Everolimus; Female; Humans; Hydroxamic Acids; Indoles; Injections, Intravenous; Leukocytes, Mononuclear; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Panobinostat; Sirolimus; Treatment Outcome

Sirolimus is the eponymous inhibitor of the mTOR; however, only its analogs have been approved as cancer therapies. Nevertheless, sirolimus is readily available, has been well studied in organ transplant patients, and shows efficacy in several preclinical cancer models.. Three simultaneously conducted phase I studies in advanced cancer patients used an adaptive escalation design to find the dose of oral, weekly sirolimus alone or in combination with either ketoconazole or grapefruit juice that achieves similar blood concentrations as its intravenously administered and approved prodrug, temsirolimus. In addition, the effect of sirolimus on inhibition of p70S6 kinase phosphorylation in peripheral T cells was determined.. Collectively, the three studies enrolled 138 subjects. The most commonly observed toxicities were hyperglycemia, hyperlipidemia, and lymphopenia in 52%, 43%, and 41% of subjects, respectively. The target sirolimus area under the concentration curve (AUC) of 3,810 ng-h/mL was achieved at sirolimus doses of 90, 16, and 25 mg in the sirolimus alone, sirolimus plus ketoconazole, and sirolimus plus grapefruit juice studies, respectively. Ketoconazole and grapefruit juice increased sirolimus AUC approximately 500% and 350%, respectively. Inhibition of p70 S6 kinase phosphorylation was observed at all doses of sirolimus and correlated with blood concentrations. One partial response was observed in a patient with epithelioid hemangioendothelioma.. Sirolimus can be feasibly administered orally, once weekly with a similar toxicity and pharmacokinetic profile compared with other mTOR inhibitors and warrants further evaluation in studies of its comparative effectiveness relative to recently approved sirolimus analogs.

Topics: Adult; Aged; Aged, 80 and over; Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Citrus paradisi; Female; Humans; Hyperglycemia; Hyperlipidemias; Ketoconazole; Lymphopenia; Male; Middle Aged; Neoplasm Staging; Neoplasms; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; TOR Serine-Threonine Kinases

This dedicated QTc study was designed to evaluate the effect of the mammalian target of rapamycin inhibitor, ridaforolimus, on the QTc interval in patients with advanced malignancies.. We conducted a fixed-sequence, single-blind, placebo-controlled study. Patients (n = 23) received placebo on day 1 and a single 100-mg oral dose of ridaforolimus on day 2 in the fasted state. Holter electrocardiogram (ECG) monitoring was performed for 24 h after each treatment, and blood ridaforolimus concentrations were measured for 24 h after dosing. The ECGs were interpreted in a blinded fashion, and the QT interval was corrected using Fridericia's formula (QTcF). After a washout of at least 5 days, 22 patients went on to receive a therapeutic regimen of ridaforolimus (40 mg orally once daily for 5 days per week).. The upper limit of the two-sided 90 % confidence interval for the placebo-adjusted mean change from baseline in QTcF was <10 ms at each time point. No patient had a QTcF change from baseline >30 ms or QTcF interval >480 ms. Geometric mean exposure to ridaforolimus after the single 100-mg dose was comparable to previous experience with the therapeutic regimen. There appeared to be no clear relationship between individual QTcF change from baseline and ridaforolimus blood concentrations. Ridaforolimus was generally well tolerated, with adverse events consistent with prior studies.. Administration of the single 100-mg dose of ridaforolimus did not cause a clinically meaningful prolongation of QTcF, suggesting that patients treated with ridaforolimus have a low likelihood of delayed ventricular repolarization.

Topics: Adult; Aged; Electrocardiography; Female; Humans; Male; Middle Aged; Neoplasms; Single-Blind Method; Sirolimus; TOR Serine-Threonine Kinases

VEGF, mTOR, and EGFR inhibitors have demonstrated anti-tumor and anti-angiogenic effects alone and in combination with each other. This study evaluated the safety, tolerability, and pharmacokinetics of bevacizumab, everolimus, and erlotinib combination.. Doublet therapy consisted of bevacizumab at 10 mg/kg every 14 days and everolimus 5 mg daily which escalated to 10 mg daily. Erlotinib 75 mg daily was added to the phase II dose recommended phase II dose (RPTD) of bevacizumab and everolimus. Dose-limiting toxicity (DLT) was assessed in cycle 1.. Forty-eight patients with advanced solid malignancies were evaluable for DLT and efficacy. No DLTs were observed in the doublet dose escalation. Two DLTs (grade 3 mucositis and grade 3 rash) were observed with the addition of erlotinib 75 mg daily. Consequently, triplet doses were adjusted and were better tolerated. Four patients had a partial response. Median progression-free survival (PFS) for the doublet therapy was 6.0 months (0.5 to 32+ months) and 5.5 months (0.8 to 27+ months) for the triplet therapy. Systemic exposure of everolimus was significantly higher in combination with erlotinib (476 ± 161 ng h/mL) compared to when given alone (393 ± 156 ng h/mL; P = 0.020).. The RPTD for the doublet therapy is bevacizumab 10 mg/kg every 14 days and everolimus 10 mg daily, and the RPTD for the triplet therapy is bevacizumab 5 mg/kg every 14 days, everolimus 5 mg and erlotinib 75 mg daily. Prolonged disease stability was demonstrated in tumors known to respond to mTOR inhibition and potentially resistant to VEGF blockade.

Topics: Adult; Aged; Angiogenesis Inhibitors; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Disease-Free Survival; Erlotinib Hydrochloride; Everolimus; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Quinazolines; Sirolimus; Treatment Outcome

Preclinical models demonstrate synergistic antitumor activity with combination blockade of mTOR and IGF-1R signaling. We aimed to determine the safety, tolerability, and recommended phase II dose (RP2D) of the combination of figitumumab, a fully human IgG(2) anti-insulin-like growth factor-1 receptor (IGF-1R) monoclonal antibody (Pfizer) and the mTOR inhibitor, everolimus (Novartis). Pharmacokinetics and preliminary antitumor effects of the combination were evaluated.. Phase I trial in patients with advanced sarcomas and other solid tumors. Initial cohort combined full phase 2 dose figitumumab (20 mg/kg IV every 21 days) with full dose everolimus (10 mg orally once daily). Intercohort dose de-escalation was planned for unacceptable toxicities. Dose modifications were allowed beyond cycle 1.. No DLTs were observed in the initial cohort during cycle one, therefore full dose figitumumab and everolimus was declared the RP2D. In total, 21 patients were enrolled on study. Most toxicities were grade 1 or 2, and were similar to reported toxicities of the single agents. Mucositis was the most frequently observed grade 3 toxicity. Median time on study was 104 days (range 17-300). Of 18 patients evaluable for response, best response was partial response in 1 patient with malignant solitary fibrous tumor and, stable disease in 15 patients. There were no apparent pharmacokinetic interactions between everolimus and figitumumab.. Combination figitumumab plus everolimus at full doses appears safe and well tolerated with no unexpected toxicities. Dose reductions in everolimus may be required after prolonged drug administration. This regimen exhibits interesting antitumor activity warranting further investigation.

Topics: Adult; Aged; Antibodies, Monoclonal; Antineoplastic Combined Chemotherapy Protocols; Everolimus; Female; Humans; Immunoglobulins, Intravenous; Male; Middle Aged; Neoplasms; Receptor, IGF Type 1; Sarcoma; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; Tumor Burden; Young Adult

This phase I, randomized, multicenter, open-label study investigated the pharmacokinetics, safety, and efficacy of the oral mammalian target of rapamycin inhibitor everolimus in Chinese patients with advanced solid tumors.. A total of 24 patients with advanced breast cancer (n = 6), gastric cancer (n = 6), non-small cell lung cancer (n = 6), or renal cell carcinoma (n = 6) who were refractory to/unsuitable for standard therapy were randomized 1:1 to oral everolimus 5 or 10 mg/day. Primary end points were pharmacokinetic parameters and safety and tolerability. Pharmacokinetic 24-h profiles were measured on day 15; trough level was measured on days 2, 8, 15, 16, and 22. Tolerability was assessed continuously. This final analysis was performed after all patients had received 6 months of study drug or had discontinued.. Everolimus was absorbed rapidly; median Tmax was 3 h (range, 1-4) and 2 h (range, 0.9-6) in the 5 and 10 mg/day groups, respectively. Pharmacokinetic parameters increased dose proportionally from the 5 and 10 mg/day doses. Steady-state levels were achieved by day 8 or earlier. The most common adverse events suspected to be related to everolimus therapy were increased blood glucose (16.7% and 41.7%) and fatigue (16.7% and 33.3%) in the everolimus 5 and 10 mg/day dose cohorts, respectively. Best tumor response was stable disease in 10 (83%) and 6 (50%) patients in the 5 and 10 mg/day groups, respectively.. Everolimus 5 or 10 mg/day was well tolerated in Chinese patients with advanced solid tumors. The observed safety and pharmacokinetic profile of everolimus from this study were consistent with previous studies.. Chinese Health Authorities 2008L09346.

Topics: Adult; Aged; Antineoplastic Agents; Dose-Response Relationship, Drug; Everolimus; Female; Humans; Male; Middle Aged; Neoplasms; Sirolimus; Treatment Outcome

We performed a single institution, phase I study of sirolimus and bevacizumab, in order to determine the dose limiting toxicity (DLT) and recommended phase II doses.. Eligible patients had previously treated advanced malignancies and were enrolled in three cohorts. Sirolimus 90 mg PO weekly (45 mg on days 1 and 2) was combined with bevacizumab 7.5mg/kg (cohort #1) or bevacizumab 15 mg/kg (cohort #2) IV q3weeks. Sirolimus 4 mg PO daily was combined with bevacizumab 15 mg/kg IV q3weeks (cohort #3).. Twenty-eight patients enrolled. The most common tumour types were colorectal (21%), head/neck (14%), and renal cell (11%). No DLTs were observed in cohorts #1 (4 patients) and #2 (12 patients), while two DLTs (grade 3 confusion and grade 3 fatigue) were observed in the first six patients in cohort #3 (12 patients). The most common grade 3 toxicities were fatigue (18%), hypertension (14%) and anorexia (11%). There were no responses, but one patient has had stable disease for 78 weeks.. The combination of sirolimus and bevacizumab at full doses is tolerable in the majority of patients. The availability and cost of sirolimus compared with other mTOR inhibitors make this an attractive agent to combine with bevacizumab.

Topics: Adult; Aged; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bevacizumab; Carcinoma, Renal Cell; Cohort Studies; Colorectal Neoplasms; Female; Humans; Kidney Neoplasms; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Sirolimus is the prototypical mTOR inhibitor. Sorafenib and sunitinib are small molecule inhibitors of multiple kinases including VEGF receptor (VEGFR) kinases. These agents have different mechanisms of action, providing a strong rationale for combination.. Patients with advanced cancer were assigned to receive either sirolimus or the VEGFR inhibitor alone for a 2-week lead-in period, followed by combination therapy. The primary end point of each trial was to determine whether a drug interaction exists between sirolimus and either sorafenib or sunitinib, as defined by a difference in C(max) for each drug alone compared with its C(max) during combination therapy.. The sorafenib and sunitinib trials enrolled 34 and 23 patients, respectively. There were no clinically significant differences in C(max) for any of the drugs alone compared with the C(max) during combination therapy. Toxicity profiles were similar to those expected for each drug alone. One patient with adrenal cortical cancer had a partial response to sirolimus and sunitnib.. Sirolimus can be safely combined with sorafenib or sunitinib. Our trial design is feasible and informative in screening for potential drug-drug interactions, using a relatively small number of patients and limited pharmacokinetic sampling.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; Benzenesulfonates; Drug Interactions; Female; Humans; Indoles; Male; Middle Aged; Neoplasms; Niacinamide; Phenylurea Compounds; Pyridines; Pyrroles; Sirolimus; Sorafenib; Sunitinib; Treatment Outcome; Young Adult

To determine dose-limiting toxicities, maximum-tolerated dose (MTD), pharmacokinetics, and pharmacodynamics of weekly intravenous temsirolimus, a mammalian target of rapamycin (mTOR) signaling pathway inhibitor, in pediatric patients with recurrent or refractory solid tumors.. Cohorts of three to six patients 1 to 21 years of age with recurrent or refractory solid tumors were treated with a 1-hour intravenous infusion of temsirolimus weekly for 3 weeks per course at one of four dose levels: 10, 25, 75, or 150 mg/m(2). During the first two courses, pharmacokinetic and pharmacodynamic evaluations (phosphorylation of S6, AKT, and 4EBP1 in peripheral-blood mononuclear cells) were performed.. Dose-limiting toxicity (grade 3 anorexia) occurred in one of 18 evaluable patients at the 150 mg/m(2) level, which was determined to be tolerable, and an MTD was not identified. In 13 patients evaluable for response after two courses of therapy, one had complete response (CR; neuroblastoma) and five had stable disease (SD). Four patients (three SDs + one CR) remained on treatment for more than 4 months. The sum of temsirolimus and sirolimus areas under the concentration-time curve was comparable to values in adults. AKT and 4EBP1 phosphorylation were inhibited at all dose levels, particularly after two courses.. Weekly intravenous temsirolimus is well tolerated in children with recurrent solid tumors, demonstrates antitumor activity, has pharmacokinetics similar to those in adults, and inhibits the mTOR signaling pathway in peripheral-blood mononuclear cells. Further studies are needed to define the optimal dose for use in combination with other antineoplastic agents in pediatric patients.

Topics: Adaptor Proteins, Signal Transducing; Adolescent; Antineoplastic Agents; Cell Cycle Proteins; Child; Child, Preschool; Drug Administration Schedule; Female; Humans; Infant; Infusions, Intravenous; Male; Maximum Tolerated Dose; Neoplasms; Phosphoproteins; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome; United States; Young Adult

Mammalian target of rapamycin (mTOR) inhibitors mediate AKT activation through a type 1 insulin-like growth factor receptor (IGF-1R)-dependent mechanism. Combining the mTOR inhibitor temsirolimus with cixutumumab, a fully human immunoglobulin G1 monoclonal antibody directed against IGF-1R, was expected to enhance mTOR-targeted anticancer activity by modulating resistance to mTOR inhibition. The objectives of this phase I study were to evaluate the tolerability and activity of temsirolimus and cixutumumab.. Patients in sequential cohorts ("3 + 3" design) received escalating doses of temsirolimus with cixutumumab weekly for 28 days. At the maximum tolerated dose (MTD), 21 patients were randomized into three separate drug sequence treatment groups for serial blood draws and 2[18F]fluoro-2-deoxy-d-glucose positron emission tomography combined with X-ray computed tomography (FDG-PET/CT) scans for pharmacodynamic analyses (PD).. Forty-two patients with advanced cancer (19 male/23 female, median age = 53, median number of prior therapies = 4) were enrolled. MTD was reached at cixutumumab, 6 mg/kg IV and temsirolimus, 25 mg IV. Dose-limiting toxicities included grade 3 mucositis, febrile neutropenia, and grade 4 thrombocytopenia. The most frequent toxicities were hypercholesterolemia, hypertriglyceridemia, hyperglycemia, thrombocytopenia, and mucositis. Tumor reduction was observed in 2 of 3 patients with Ewing's sarcoma and in 4 of 10 patients with adrenocortical carcinoma. PD data suggest that cixutumumab alone or combined with temsirolimus increased plasma IGF-1 and IGF binding protein 3. FDG-PET/CT showed the odds of achieving stable disease decreased by 58% (P = 0.1213) with a one-unit increase in absolute change of standard uptake value from baseline to day 3.. Temsirolimus combined with cixutumumab was well tolerated. We are currently enrolling expansion cohorts at the MTD for Ewing's sarcoma and adrenocortical carcinoma.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Female; Humans; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Male; Middle Aged; Multimodal Imaging; Neoplasm Staging; Neoplasms; Positron-Emission Tomography; Protein Kinase Inhibitors; Sirolimus; Tomography, X-Ray Computed; Treatment Outcome; Young Adult

An oral formulation of temsirolimus (Torisel), an inhibitor of the mammalian target of rapamycin, was evaluated on an intermittent schedule (once daily for 5 days every 2 weeks) in patients with advanced cancer. The maximum tolerated dose was determined to be 75 mg after dose-limiting toxicities of grade 3 elevated aminotransferases (1 patient) and grade 3 rash (1 patient) occurred with a 100-mg dose. The most common temsirolimus-related adverse events were mucositis, rash/maculopapular rash, and asthenia. Six of 12 patients who received the 75-mg dose required dose reductions due to temsirolimus-related adverse events. Two patients who received 75-mg temsirolimus and did not have dose reductions had minor tumor responses. Relative exposure from contributions of both temsirolimus and sirolimus, the principal metabolite, was 17.9% of the 75-mg dose. Thus, oral temsirolimus, 75 mg administered once daily for 5 days every 2 weeks, was further evaluated in patients with metastatic breast cancer.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Intracellular Signaling Peptides and Proteins; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Protein Serine-Threonine Kinases; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

To determine the pharmacokinetics and safety of RAD001 (everolimus) in Japanese patients with advanced solid tumors.. An open-label, non-randomized, dose-escalation Phase I study of RAD001 administered continuously once daily in a 28-day cycle was performed. The study had a '3 + 3' design, with three patients recruited to each of three successive cohorts treated with RAD001 at 2.5, 5.0 or 10.0 mg/day.. The pharmacokinetics of RAD001 in Japanese patients were similar to those previously determined in Caucasians. The drug safety profile was consistent with that of a mammalian target of rapamycin inhibitor. No dose-limiting toxicities were observed. One patient with esophageal cancer and one with gastric cancer treated with RAD001 at 10 mg/day showed marked tumor responses.. Treatment of Japanese cancer patients with RAD001 may be undertaken with the expectation that previously determined pharmacokinetic and safety profiles apply. The drug may hold promise for treatment of esophageal and gastric cancer.

Topics: Aged; Asian People; Colorectal Neoplasms; Dose-Response Relationship, Drug; Drug Administration Schedule; Esophageal Neoplasms; Everolimus; Female; Humans; Immunosuppressive Agents; Liver Neoplasms; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Neoplasms; Sirolimus; Stomach Neoplasms; Survival Analysis; Thyroid Neoplasms; Treatment Outcome

The additive cytotoxicity in vitro prompted a clinical study evaluating the non-prodrug rapamycin analogue ridaforolimus (AP23573; MK-8669; formerly deforolimus) administered i.v. combined with paclitaxel (PTX; Taxol).. Patients with taxane-sensitive solid tumors were eligible. The main dose escalation foresaw 50% ridaforolimus increments from 25 mg with a fixed PTX dose of 80 mg/m(2), both given weekly 3 weeks in a 4-week cycle. Collateral levels with a lower dose of either drug were planned upon achievement of the maximum tolerated dose in the main escalation. Pharmacodynamic studies in plasma, peripheral blood mononuclear cells (PBMCs) and skin biopsies and pharmacokinetic (PK) interaction studies at cycles 1 and 2 were carried out.. Two recommended doses were determined: 37.5 mg ridaforolimus/60 mg/m(2) PTX and 12.5 mg/80 mg/m(2). Most frequent toxic effects were mouth sores (79%), anemia (79%), fatigue (59%), neutropenia (55%) and dermatitis (48%). Two partial responses were observed in pharyngeal squamous cell and pancreatic carcinoma. Eight patients achieved stable disease > or =4 months. No drug interaction emerged from PK studies. Decrease of eukaryotic initiation factor 4E-binding protein1 (4E-BP1) phosphorylation was shown in PBMCs. Similar inhibition of phosphorylation of 4E-BP1 and mitogen-activated protein kinase was present in reparative epidermis and vascular tissues, respectively.. Potential antiangiogenic effects and encouraging antitumor activity justify further development of the combination.

Topics: Adult; Aged; Algorithms; Antineoplastic Combined Chemotherapy Protocols; Disease-Free Survival; Drug Administration Schedule; Drug Interactions; Female; Humans; Injections, Intravenous; Intracellular Signaling Peptides and Proteins; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Paclitaxel; Protein Serine-Threonine Kinases; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Temsirolimus (CCI-779) is a novel inhibitor of the mammalian target of rapamycin. This Phase 1 study was aimed at investigating the maximum-tolerated dose, toxicity, pharmacokinetics and antitumor activity in Japanese patients with advanced solid tumors.. Temsirolimus was given as a 30 min intravenous infusion once a week. Patients with solid tumors not amenable to standard forms of treatment were eligible. Dose escalation of temsirolimus was planned from 15, 45, 80 to 165 mg/m(2). The pharmacokinetics of temsirolimus and sirolimus in whole blood were examined for cycles 1, 2, 4 and 5 of treatment.. Ten patients (median age 60.5 years; range 41-69 years) with advanced solid tumors were enrolled. Their primary cancers were renal cell carcinoma (five patients), lung cancer (three patients) and colorectal cancer (two patients). The major toxicities were hypophosphatemia diarrhea, hyperglycemia, stomatitis, pyrexia, elevated aspartate aminotransferase, rash, reduced neutrophil count, elevated alanine aminotransferase, anorexia, hypertriglyceridemia and somnolence. Two of three patients who received temsirolimus 45 mg/m(2) developed dose-limiting toxicities of Grade 3 stomatitis (one patient) and Grade 3 diarrhea (two patients). The maximum-tolerated dose was 15 mg/m(2). The peak blood concentrations of temsirolimus and sirolimus, a major active metabolite, increased in a dose-dependent manner. The area under the concentration-versus-time curve of sirolimus, but not temsirolimus, increased in a dose-dependent manner.. The recommended dose for Phase 2 clinical studies of temsirolimus in Japanese patients with advanced solid tumors is 15 mg/m(2) intravenously once a week.

Topics: Adult; Aged; Anti-Allergic Agents; Antineoplastic Agents; Area Under Curve; Carcinoma, Renal Cell; Colorectal Neoplasms; Diarrhea; Diphenhydramine; Disorders of Excessive Somnolence; Drug Administration Schedule; Drug Eruptions; Fever; Humans; Hyperglycemia; Hypertriglyceridemia; Hypophosphatemia; Infusions, Intravenous; Intestinal Perforation; Kidney Neoplasms; Lung Neoplasms; Maximum Tolerated Dose; Middle Aged; Neoplasms; Neutropenia; Premedication; Sirolimus; Stomatitis; Treatment Outcome

Synergistic/additive cytotoxicity in tumor models and widespread applicability of fluoropyrimidines in solid tumors prompted the study of the combination of the mammalian target of rapamycin (mTOR) inhibitor, non-prodrug rapamycin analog ridaforolimus, with capecitabine.. Thirty-two adult patients were treated. Intravenous ridaforolimus was given once weekly for 3 weeks and capecitabine was given from days 1 to 14 every 4 weeks. Ridaforolimus was given at 25, 37.5, 50, or 75 mg with capecitabine at 1,650 mg/m(2) or 1,800 mg/m(2) divided into two daily doses. Pharmacokinetics of both drugs were determined during cycles 1 and 2. Pharmacodynamic studies in peripheral blood mononuclear cells (PBMCs) and wound tissue of the skin characterized pathways associated with the metabolism or disposition of fluoropyrimidines and mTOR and ERK signaling.. Two recommended doses (RDs) were defined: 75 mg ridaforolimus/1,650 mg/m(2) capecitabine and 50 mg ridaforolimus/1,800 mg/m(2) capecitabine. Dose-limiting toxicities were stomatitis and skin rash. One patient achieved a partial response lasting 10 months and 10 of 29 evaluable patients had stable disease for ≥ 6 months. The only pharmacokinetic interaction was a ridaforolimus-induced increase in plasma exposure to fluorouracil. PBMC data suggested that prolonged exposure to capecitabine reduced the ridaforolimus inhibition of mTOR. Ridaforolimus influenced the metabolism of fluoropyrimidines and inhibited dihydropyrimidine dehydrogenase, behavior similar to that of rapamycin. Inhibition of the target thymidylate synthase by capecitabine was unaffected. mTOR and ERK signaling was inhibited in proliferating endothelial cells and was more pronounced at the RD with the larger amount of ridaforolimus.. Good tolerability, feasibility of prolonged treatment, antitumor activity, and favorable pharmacologic profile support further investigation of this combination.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Angiogenesis Inhibitors; Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Biopsy; Capecitabine; Cell Cycle Proteins; Deoxycytidine; Dihydrouracil Dehydrogenase (NADP); Drug Administration Schedule; Europe; Female; Fluorouracil; Granulation Tissue; Humans; Intracellular Signaling Peptides and Proteins; Leukocytes, Mononuclear; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Phosphoproteins; Phosphorylation; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Sirolimus; Skin; Thymidine Phosphorylase; Thymidylate Synthase; TOR Serine-Threonine Kinases; Treatment Outcome

The combination of sorafenib (vascular endothelial growth factor receptor 2 inhibitor) and sirolimus (mammalian target of rapamycin inhibitor) might work synergistically.. A phase I dose-escalation study with sorafenib twice a day (b.i.d.) and sirolimus once daily (q.d.) was performed to determine the recommended dose of the combination in patients with solid tumours. Secondary objectives were to determine the safety profile and maximum tolerated dose (MTD), and to evaluate the pharmacokinetics (PK) of the combination.. Dose-limiting toxicities were transaminitis and cutaneous toxicity. The most frequently reported adverse events were elevated transaminases, hypophosphatemia, fatigue, anorexia, diarrhoea, nausea, rash and palmar-plantar erythrodysaesthesia. Sirolimus did not change the PK of sorafenib; in contrast, sorafenib reduced the AUC(0-96) and C(max) of sirolimus. No objective responses were observed; eight patients showed stable disease for a median of 16.3 weeks (range 8-24). The MTD of the combination was sorafenib 200  mg b.i.d. with sirolimus 1 mg q.d.. The combination of sorafenib and sirolimus showed enhanced toxicity, which could not be explained by the PK of both drugs. The relative low doses at the MTD, in combination with the PK results, do not warrant further development of this combination.

Topics: Adult; Antineoplastic Combined Chemotherapy Protocols; Benzenesulfonates; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Niacinamide; Phenylurea Compounds; Pyridines; Sirolimus; Sorafenib; TOR Serine-Threonine Kinases; Vascular Endothelial Growth Factor Receptor-2

The efficacy and safety of converting maintenance renal transplant recipients from calcineurin inhibitors (CNIs) to sirolimus (SRL) was evaluated.. Eight hundred thirty renal allograft recipients, 6 to 120 months posttransplant and receiving cyclosporine or tacrolimus, were randomly assigned to continue CNI (n=275) or convert from CNI to SRL (n=555). Primary endpoints were calculated Nankivell glomerular filtration rate (GFR; stratified at baseline: 20-40 vs. >40 mL/min) and the cumulative rates of biopsy-confirmed acute rejection (BCAR), graft loss, or death at 12 months. Enrollment in the 20 to 40 mL/min stratum was halted prematurely because of a higher incidence of safety endpoints in the SRL conversion arm.. Intent-to-treat analyses at 12 and 24 months showed no significant treatment difference in GFR in the baseline GFR more than 40 mL/min stratum. On-therapy analysis of this cohort showed significantly higher GFR at 12 and 24 months after SRL conversion. Rates of BCAR, graft survival, and patient survival were similar between groups. Median urinary protein-to-creatinine ratios (UPr/Cr) were similar at baseline but increased significantly after SRL conversion. Malignancy rates were significantly lower at 12 and 24 months after SRL conversion. Post hoc analyses identified a subgroup with baseline GFR more than 40 mL/min and UPr/Cr less than or equal to 0.11, whose risk-benefit profile was more favorable after conversion than that for the overall SRL conversion cohort.. At 2 years, SRL conversion among patients with baseline GFR more than 40 mL/min was associated with excellent patient and graft survival, no difference in BCAR, increased urinary protein excretion, and a lower incidence of malignancy compared with CNI continuation. Superior renal function was observed among patients who remained on SRL through 12 to 24 months, particularly in the subgroup of patients with baseline GFR more than 40 mL/min and UPr/Cr less than or equal to 0.11.

Topics: Adolescent; Adult; Aged; Biopsy; Calcineurin Inhibitors; Cyclosporine; Drug Therapy, Combination; Female; Glomerular Filtration Rate; Graft Rejection; Graft Survival; Humans; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Neoplasms; Prospective Studies; Sirolimus; Tacrolimus; Time Factors; Transplantation, Homologous; Treatment Outcome; Young Adult

This was a phase I trial to determine the maximum tolerated dose and toxicity of deforolimus (AP23573, MK-8669), an inhibitor of mammalian target of rapamycin (mTOR). The pharmacokinetics, pharmacodynamics, and antineoplastic effects were also studied.. Deforolimus was administered intravenously over 30 min every 7 days according to a flat dosing schedule. Dose was escalated according to an accelerated titration design. Patients remained on study until disease progression as long as they tolerated the drug without significant toxicities.. Forty-six patients were enrolled on the study. Common side effects included fatigue, anorexia, and mucositis. The maximum tolerated dose was 75 mg and mucositis was the dose-limiting toxicity. Similar to other mTOR inhibitors, deforolimus exhibited nonlinear pharmacokinetics and a prolonged half-life. Among 34 patients evaluable for response, 1 patient had a partial response, 21 patients had stable disease, and 12 had progressed. Percent change in tumor size was significantly associated with AUC (P=0.015). A significant association was also detected for maximum change in cholesterol within the first two cycles of therapy and change in tumor size (r=-0.38; P=0.029).. Deforolimus was well tolerated on the schedule tested in this trial with toxicity and pharmacokinetic profiles that were similar to that of other mTOR inhibitors. Additional phase II studies are needed to determine if deforolimus is superior to other mTOR inhibitors in terms of efficacy. The change in serum cholesterol as a potential biomarker of activity should be studied further.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Cell Cycle Proteins; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Mucositis; Neoplasms; Phosphoproteins; Phosphorylation; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG-PET) has increasingly been used to evaluate the efficacy of anticancer agents. We investigated the role of FDG-PET as a predictive marker for response to mammalian target of rapamycin (mTOR) inhibition in advanced solid tumor patients and in murine xenograft models.. Thirty-four rapamycin-treated patients with assessable baseline and treatment FDG-PET and computed tomography scans were analyzed from two clinical trials. Clinical response was evaluated according to Response Evaluation Criteria in Solid Tumors, and FDG-PET response was evaluated by quantitative changes and European Organisation for Research and Treatment of Cancer (EORTC) criteria. Six murine xenograft tumor models were treated with temsirolimus. Small animal FDG-PET scans were performed at baseline and during treatment. The tumors were analyzed for the expression of pAkt and GLUT1.. Fifty percent of patients with increased FDG-PET uptake and 46% with decreased uptake had progressive disease (PD). No objective response was observed. By EORTC criteria, the sensitivity of progressive metabolic disease on FDG-PET in predicting PD was 19%. Preclinical studies demonstrated similar findings, and FDG-PET response correlated with pAkt activation and plasma membrane GLUT1 expression.. FDG-PET is not predictive of proliferative response to mTOR inhibitor therapy in both clinical and preclinical studies. Our findings suggest that mTOR inhibitors suppress the formation of mTORC2 complex, resulting in the inhibition of Akt and glycolysis independent of proliferation in a subset of tumors. Changes in FDG-PET may be a pharmacodynamic marker for Akt activation during mTOR inhibitor therapy. FDG-PET may be used to identify patients with persistent Akt activation following mTOR inhibitor therapy.

Topics: Animals; Antibiotics, Antineoplastic; Cell Line, Tumor; Cell Proliferation; Disease Progression; Female; Fluorodeoxyglucose F18; Glucose Transporter Type 1; Humans; Mice; Mice, Nude; Neoplasms; Patient Selection; Phosphorylation; Positron-Emission Tomography; Predictive Value of Tests; Protein Kinases; Proto-Oncogene Proteins c-akt; Radiopharmaceuticals; Sirolimus; Tomography, X-Ray Computed; TOR Serine-Threonine Kinases; Treatment Outcome; Xenograft Model Antitumor Assays

We sought to investigate the long-term efficacy of oral sirolimus therapy and its impact on the incidence of de novo malignancies in the OSIRIS (Oral Sirolimus to Inhibit Recurrent In-Stent Stenosis) trial population.. The OSIRIS trial showed a significant reduction of angiographic restenosis with an oral adjunctive sirolimus treatment for in-stent restenosis. The long-term efficacy of oral sirolimus therapy is unknown.. Three hundred patients with in-stent restenosis were randomly assigned to receive placebo, a cumulative loading dose of 8 mg (usual-dose), or 24 mg (high-dose) of sirolimus over 3 days (2 days before and the day of intervention) followed by maintenance therapy of 2 mg/day for 7 days. The primary outcome of this analysis was the incidence of composite of death, myocardial infarction, and target vessel revascularization at 4-year follow-up. Secondary outcome was the incidence of newly diagnosed malignancies.. No significant differences were observed between placebo, usual-, and high-dose sirolimus treatment groups regarding primary outcome (33.3%, 39.4%, and 31.3%, respectively; p = 0.46), death (5.9%, 9.1%, and 11.1%, respectively; p = 0.41), target vessel revascularization (30.4%, 30.3%, and 22.2%, respectively; p = 0.33), and rate of newly diagnosed malignancies (7.8%, 3.0%, and 11.1%, respectively; p = 0.09).. The benefit in the reduced need for repeat intervention observed at 1 year with high-dose oral sirolimus therapy was attenuated over 4 years. Moreover, this regimen was associated with numerical yet not a significant increase in newly diagnosed malignancies without augmenting the malignancy-induced risk of death. (Oral Sirolimus for In-Stent Restenosis [OSIRUS] trial; NCT00859183).

Topics: Administration, Oral; Aged; Aged, 80 and over; Angioplasty, Balloon, Coronary; Cardiovascular Agents; Coronary Angiography; Coronary Restenosis; Double-Blind Method; Humans; Immunosuppressive Agents; Kaplan-Meier Estimate; Middle Aged; Myocardial Infarction; Neoplasms; Risk Assessment; Sirolimus; Time Factors

Pharmacodynamic studies are frequently incorporated into phase I trials, but it is uncommon that they guide dose selection. We conducted a dose selection study with daily rapamycin (sirolimus) in patients with solid tumors employing a modified continuous reassessment method (mCRM) using real-time pharmacodynamic data as primary dose-estimation parameter.. We adapted the mCRM logit function from its classic toxicity-based input data to a pharmacodynamic-based input. The pharmacodynamic end point was skin phospho-P70 change after 28 days. Pharmacodynamic effect was defined as at least 80% inhibition from baseline. The first two dose levels (2 and 3 mg) were evaluated before implementing the mCRM, and the data used to estimate the next dose level based on statistical modeling. Toxicity-based boundaries limited the escalation steps. Other correlates analyzed were positron emission tomography (PET) and computed tomography, pharmacokinetics, phospho-P70 in peripheral-blood mononuclear cells, and tumor biopsies in patients at the maximum-tolerated dose (MTD).. Twenty-one patients were enrolled at doses between 2 and 9 mg. Pharmacodynamic effect occurred across dose levels, and toxicity boundaries ultimately drove dose selection. The MTD of daily oral rapamycin was 6 mg. Toxicities in at least 20% were hyperglycemia, hyperlipidemia, elevated transaminases, anemia, leucopenia, neutropenia, and mucositis. Pharmacokinetics were consistent with prior data, and exposure increased with dose. No objective responses occurred, but five previously progressing patients received at least 12 cycles. PET showed generalized stable or decreased glucose uptake unrelated to antitumor effect.. mCRM-based dose escalation using real-time pharmacodynamic assessment was feasible. However, the selected pharmacodynamic end point did not correlate with dose. Toxicity ultimately drove dose selection. Rapamycin is a well-tolerated and active oral anticancer agent.

Topics: Adult; Aged; Aged, 80 and over; Antibiotics, Antineoplastic; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Leukocytes, Mononuclear; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Positron-Emission Tomography; Sirolimus

This phase I trial was conducted to determine the safety, tolerability, pharmacokinetics, and pharmacodynamics of deforolimus (previously known as AP23573; MK-8669), a nonprodrug rapamycin analog, in patients with advanced solid malignancies.. Patients were treated using an accelerated titration design with sequential escalating flat doses of deforolimus administered as a 30-minute intravenous infusion once daily for 5 consecutive days every 2 weeks (QDx5) in a 28-day cycle. Safety, pharmacokinetic, pharmacodynamic, and tumor response assessments were performed.. Thirty-two patients received at least one dose of deforolimus (3 to 28 mg/d). Three dose-limiting toxicity events of grade 3 mouth sores were reported. The maximum-tolerated dose (MTD) was 18.75 mg/d. Common treatment-related adverse events included reversible mouth sores and rash. Whole-blood clearance increased with dose. Pharmacodynamic analyses demonstrated mammalian target of rapamycin inhibition at all dose levels. Four patients (one each with non-small-cell lung cancer, mixed müllerian tumor [carcinosarcoma], renal cell carcinoma, and Ewing sarcoma) experienced confirmed partial responses, and three additional patients had minor tumor regressions.. The MTD of this phase I trial using an accelerated titration design was determined to be 18.75 mg/d. Deforolimus was well tolerated and showed encouraging antitumor activity across a broad range of malignancies when administered intravenously on the QDx5 schedule. On the basis of these overall results, a dose of 12.5 mg/d is being evaluated in phase II trials.

Topics: Adult; Aged; Antineoplastic Agents; Area Under Curve; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Injections, Intravenous; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Prognosis; Protein Kinases; Sirolimus; Survival Rate; TOR Serine-Threonine Kinases

To use preclinical and clinical pharmacokinetic (PK)/pharmacodynamic (PD) modeling to predict optimal clinical regimens of everolimus, a novel oral mammalian target of rapamycin (mTOR) inhibitor, to carry forward to expanded phase I with tumor biopsy studies in cancer patients.. Inhibition of S6 kinase 1 (S6K1), a molecular marker of mTOR signaling, was selected for PD analysis in peripheral blood mononuclear cells (PBMCs) in a phase I clinical trial. PK and PD were measured up to 11 days after the fourth weekly dose. A PK/PD model was used to describe the relationship between everolimus concentrations and S6K1 inhibition in PBMCs of cancer patients and in PBMCs and tumors of everolimus-treated CA20948 pancreatic tumor-bearing rats.. Time- and dose-dependent S6K1 inhibition was demonstrated in human PBMCs. In the rat model, a relationship was shown between S6K1 inhibition in tumors or PBMCs and antitumor effect. This allowed development of a direct-link PK/PD model that predicted PBMC S6K1 inhibition-time profiles in patients. Comparison of rat and human profiles simulated by the model suggested that a weekly 20- to 30-mg dose of everolimus would be associated with an antitumor effect in an everolimus-sensitive tumor and that daily administration would exert a greater effect than weekly administration at higher doses.. A direct-link PK/PD model predicting the time course of S6K1 inhibition during weekly and daily everolimus administration allowed extrapolation from preclinical studies and first clinical results to select optimal doses and regimens of everolimus to explore in future clinical trials.

Topics: Animals; Dose-Response Relationship, Drug; Drug Administration Schedule; Everolimus; Humans; Immunosuppressive Agents; Models, Biological; Neoplasms; Pancreatic Neoplasms; Rats; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus

Everolimus is a selective mammalian target of rapamycin (mTOR) inhibitor with promising anticancer activity. In order to identify a rationally based dose and schedule for cancer treatment, we have conducted a tumor pharmacodynamic phase I study in patients with advanced solid tumors.. Fifty-five patients were treated with everolimus in cohorts of 20, 50, and 70 mg weekly or 5 and 10 mg daily. Dose escalation depended on dose limiting toxicity (DLT) rate during the first 4-week period. Pre- and on-treatment steady-state tumor and skin biopsies were evaluated for total and phosphorylated (p) protein S6 kinase 1, eukaryotic initiation factor 4E (elF-4E) binding protein 1 (4E-BP1), eukaryotic initiation factor 4G (eIF-4G), AKT, and Ki-67 expression. Plasma trough levels of everolimus were determined on a weekly basis before dosing during the first 4 weeks.. We observed a dose- and schedule-dependent inhibition of the mTOR pathway with a near complete inhibition of pS6 and peIF-4G at 10 mg/d and >or= 50 mg/wk. In addition, pAKT was upregulated in 50% of the treated tumors. In the daily schedule, there was a correlation between everolimus plasma trough concentrations and inhibition of peIF4G and p4E-BP1. There was good concordance of mTOR pathway inhibition between skin and tumor. Clinical benefit was observed in four patients including one patient with advanced colorectal cancer achieving a partial response. DLTs occurred in five patients: one patient at 10 mg/d (grade 3 stomatitis) and four patients at 70 mg/wk (two with grade 3 stomatitis, one with grade 3 neutropenia, and one with grade 3 hyperglycemia).. Everolimus achieved mTOR signaling inhibition at doses below the DLT. A dosage of 10 mg/d or 50 mg/wk is recommended for further development.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Dose-Response Relationship, Drug; Everolimus; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

To identify the optimal regimen and dosage of the oral mammalian target of rapamycin inhibitor everolimus (RAD001).. We performed a dose-escalation study in advanced cancer patients administering oral everolimus 5 to 30 mg/wk, with pharmacokinetic (PK) and pharmacodynamic (PD) studies. PD data prompted investigation of 50 and 70 mg weekly and daily dosing at 5 and 10 mg.. Ninety-two patients were treated. Dose-limiting toxicity was seen in one patient each at 50 mg/wk (stomatitis and fatigue) and 10 mg/d (hyperglycemia); hence, the maximum-tolerated dose was not reached. S6 kinase 1 activity in peripheral-blood mononuclear cells was inhibited for at least 7 days at doses >or= 20 mg/wk. Area under the curve increased proportional to dose, but maximum serum concentration increased less than proportionally at doses >or= 20 mg/wk. Terminal half-life was 30 hours (range, 26 to 38 hours). Partial responses were observed in four patients, and 12 patients remained progression free for >or= 6 months, including five of 10 patients with renal cell carcinoma.. Everolimus was satisfactorily tolerated at dosages up to 70 mg/wk and 10 mg/d with predictable PK. Antitumor activity and PD in tumors require further clinical investigation. Doses of 20 mg/wk and 5 mg/d are recommended as appropriate starting doses for these studies.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Dose-Response Relationship, Drug; Everolimus; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Protein Kinases; Ribosomal Protein S6 Kinases; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Calcineurin inhibitors (CNIs) have been associated with the development of posttransplant malignancies, especially lymphoma and solid organ tumors. Sirolimus (SRL) has been shown to inhibit the growth of tumor cell lines in vitro and in vivo and has proven effective in clinical practice for the treatment of Kaposi's sarcoma. Organ transplant patients treated with CNIs who develop a tumor may thus benefit from conversion to SRL.. From December 2001 to May 2006, 25 patients who developed a tumor were converted from a CNI-based immunosuppressive regimen to SRL. We analyzed the evolution of the tumor, renal function, and the adverse effects resulting from the change of immunosuppression.. The mean follow-up was 19 months. Creatinine clearance (Cockcroft-Gault) increased from 59.5 +/- 21.7 to 66.0 +/- 24.2 mL/min at 12 months (P = .4) and serum cholesterol from 176.7 +/- 46.8 to 216.4 +/- 40.3 mg/dL (P = .01). Proteinuria rose from 0.3 +/- 0.1 to 1.3 +/- 0.9 g/24 hours (P = .004). Adverse events included anemia, thrombocytopenia, and oral ulcers in 20% of cases, cutaneous eruption and gastrointestinal alterations in 12%, and edema in 24%. Four (16%) patients had improved blood pressure readings. Six (24%) patients died and one experienced an acute rejection episode after conversion to SRL. Nineteen (76%) patients displayed a favorable evolution with no evidence of tumor progression.. Conversion to SRL stabilized tumor progression in 76% of long-term renal transplant patients who developed a neoplasm over a mean follow-up of 19 months. Moreover, renal function improved. The most important adverse effects were increased cholesterol and proteinuria.

Topics: Antineoplastic Agents; Calcineurin Inhibitors; Female; Follow-Up Studies; Humans; Immunosuppressive Agents; Incidence; Kidney Transplantation; Male; Neoplasms; Postoperative Complications; Sirolimus; Time Factors

To determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetic and pharmacodynamic properties of the mammalian target of rapamycin (mTOR) inhibitor, everolimus, in children with refractory or recurrent solid tumors.. Everolimus was administered orally at a daily dose of 2.1, 3, 5, or 6.5 mg/m2 in cohorts of three to six patients per dosage level. Pharmacokinetic and pharmacodynamic studies were performed during the first course. The phosphorylation status of various components of the mTOR signal pathway was assessed in peripheral-blood mononuclear cells (PBMCs) isolated from treated patients.. There were 26 patients enrolled; 18 were assessable. DLTs included diarrhea (n = 1), mucositis (n = 1), and elevation of ALT (n = 1) at 6.5 mg/m2. At the MTD of 5 mg/m2, the median everolimus clearance was 15.2 L/h/m2, with a plasma everolimus concentration-time area under the curve (AUC) from 0 to infinity of 239.6 ng/mL x h. Significant inhibition of mTOR pathway signaling was observed in PBMCs from patients achieving AUCs 200 ng/mL x h, equivalent to dosages of 3 to 5 mg/m2 of everolimus. No objective tumor responses were observed.. Continuous, orally administered everolimus is well tolerated in children with recurrent or refractory solid tumors and demonstrates similar pharmacokinetic properties to those observed in adults. Everolimus significantly inhibits the mTOR signaling pathway in children at the MTD. The recommended phase II dose in children with solid tumors is 5 mg/m2.

Topics: Administration, Oral; Adolescent; Adult; Antineoplastic Agents; Child; Child, Preschool; Dose-Response Relationship, Drug; Drug Administration Schedule; Everolimus; Female; Humans; Male; Maximum Tolerated Dose; Neoplasms; Salvage Therapy; Sirolimus; Survival Rate; Treatment Outcome

Sirolimus (SRL) is a mammalian target of rapamycin inhibitor that, in contrast to cyclosporine (CsA), has been shown to inhibit rather than promote cancers in experimental models. At 3 mo +/- 2 wk after renal transplantation, 430 of 525 enrolled patients were randomly assigned to remain on SRL-CsA-steroids (ST) or to have CsA withdrawn and SRL troughs increased two-fold (SRL-ST). Median times to first skin and nonskin malignancies were compared between treatments using a survival analysis. Mean annualized rates of skin malignancy were calculated, and the relative risk was determined using a Poisson model. Malignancy-free survival rates for nonskin malignancies were compared using Kaplan-Meier estimates and the log-rank test. At 5 yr, the median time to a first skin carcinoma was delayed (491 versus 1126 d; log-rank test, P = 0.007), and the risk for an event was significantly lower with SRL-ST therapy (relative risk SRL-ST to SRL-CsA-ST 0.346; 95% confidence interval 0.227 to 0.526; P < 0.001, intention-to-treat analysis). The relative risks for both basal and squamous cell carcinomas were significantly reduced. Kaplan-Meier estimates of nonskin cancer were 9.6 versus 4.0% (SRL-CsA-ST versus SRL-ST; P = 0.032, intention-to-treat analysis). Nonskin cancers included those of the lung, larynx, oropharynx, kidney, gastrointestinal tract, prostate, breast, thyroid, and cervix as well as glioma, liposarcoma, astrocytoma, leukemia, lymphoma, and Kaposi's sarcoma. Patients who received SRL-based, calcineurin inhibitor-free therapy after CsA withdrawal at month 3 had a reduced incidence of both skin and nonskin malignancies at 5 yr after renal transplantation compared with those who received SRL therapy combined with CsA. Longer follow-up and additional trials are needed to confirm these promising results.

Topics: Adult; Cyclosporine; Disease-Free Survival; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Follow-Up Studies; Humans; Immunosuppressive Agents; Incidence; Kidney Transplantation; Neoplasms; Risk Assessment; Sirolimus

The most advantageous combination of immunosuppressive agents for cardiac transplant recipients has not yet been established. Between November 2001 and June 2003, 343 de novo cardiac transplant recipients were randomized to receive steroids and either tacrolimus (TAC) + sirolimus (SRL), TAC + mycophenolate mofetil (MMF) or cyclosporine (CYA) + MMF. Antilymphocyte induction therapy was allowed for up to 5 days. The primary endpoint of >/=3A rejection or hemodynamic compromise rejection requiring treatment showed no significant difference at 6 months (TAC/MMF 22.4%, TAC/SRL 24.3%, CYA/MMF 31.6%, p = 0.271) and 1 year (p = 0.056), but it was significantly lower in the TAC/MMF group when compared only to the CYA/MMF group at 1 year (23.4% vs. 36.8%; p = 0.029). Differences in the incidence of any treated rejection were significant (TAC/SRL = 35%, TAC/MMF = 42%, CYA/MMF = 59%; p < 0.001), as were median levels of serum creatinine (TAC/SRL = 1.5 mg/dL, TAC/MMF = 1.3 mg/dL, CYA/MMF = 1.5 mg/dL; p = 0.032) and triglycerides (TAC/SRL = 162 mg/dL, TAC/MMF = 126 mg/dL, CYA/MMF = 154 mg/dL; p = 0.028). The TAC/SRL group encountered fewer viral infections but more fungal infections and impaired wound healing. These secondary endpoints suggest that the TAC/MMF combination appears to offer more advantages than TAC/SRL or CYA/MMF in cardiac transplant patients, including fewer >/=3A rejections or hemodynamic compromise rejections and an improved side-effect profile.

Topics: Adult; Antiviral Agents; Cyclosporine; Cytomegalovirus Infections; Drug Therapy, Combination; Female; Graft Rejection; Heart Transplantation; Heart-Lung Transplantation; Humans; Hypolipidemic Agents; Immunosuppressive Agents; Male; Middle Aged; Mycophenolic Acid; Neoplasms; Patient Selection; Postoperative Complications; Sirolimus; Treatment Outcome; United States

ARIAD Pharmaceuticals Inc is developing intravenous and oral formulations of AP-23573, a rapamycin analog and inhibitor of mTOR (mammalian target of rapamycin) that blocks the proliferation and migration of vascular smooth muscle cells, for the potential treatment of cancer, including solid and hematological forms.

Topics: Animals; Antineoplastic Agents; Humans; Neoplasms; Protein Kinases; Sirolimus; Structure-Activity Relationship; TOR Serine-Threonine Kinases

Patients with advanced cancer received temsirolimus (Torisel, CCI-779), a novel inhibitor of mammalian target of rapamycin, i.v. once daily for 5 days every 2 weeks to determine the maximum tolerated dose, toxicity profile, pharmacokinetics, and preliminary antitumor efficacy.. Doses were escalated in successive cohorts of patients using a conventional phase I clinical trial design. Samples of whole blood and plasma were collected to determine the pharmacokinetics of temsirolimus and sirolimus, its principal metabolite.. Sixty-three patients were treated with temsirolimus (0.75-24 mg/m(2)/d). The most common drug-related toxicities were asthenia, mucositis, nausea, and cutaneous toxicity. The maximum tolerated dose was 15 mg/m(2)/d for patients with extensive prior treatment because, in the 19 mg/m(2)/d cohort, two patients had dose-limiting toxicities (one with grade 3 vomiting, diarrhea, and asthenia and one with elevated transaminases) and three patients required dose reductions. For minimally pretreated patients, in the 24 mg/m(2)/d cohort, one patient developed a dose-limiting toxicity of grade 3 stomatitis and two patients required dose reductions, establishing 19 mg/m(2)/d as the maximum acceptable dose. Immunologic studies did not show any consistent trend toward immunosuppression. Temsirolimus exposure increased with dose in a less than proportional manner. Terminal half-life was 13 to 25 hours. Sirolimus-to-temsirolimus exposure ratios were 0.6 to 1.8. A patient with non-small cell lung cancer achieved a confirmed partial response, which lasted for 12.7 months. Three patients had unconfirmed partial responses; two patients had stable disease for >/=24 weeks.. Temsirolimus was generally well tolerated on this intermittent schedule. Encouraging preliminary antitumor activity was observed.

Topics: Adult; Aged; Antineoplastic Agents; Area Under Curve; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Injections, Intravenous; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Sirolimus

To establish the safety, tolerability, and pharmacokinetic parameters of CCI-779, a selective inhibitor of the mammalian target of rapamycin, in patients with advanced cancer.. Using a modified continuous reassessment method, we performed a phase I with pharmacokinetic study of CCI-779 given as a weekly 30 minutes intravenous (I.V.) infusion.. Twenty-four patients received CCI-779 at doses ranging 7.5 to 220 mg/m(2). No immunosuppressive effect was reported. Dose-limiting thrombocytopenia occurred in two patients at 34 or 45 mg/m(2). At 220 mg/m(2), dose-limiting toxicities consisted of manic-depressive syndrome, stomatitis, and asthenia in two of nine patients, preventing further dose escalation. The most frequent drug-related toxicities were acne-like, maculopapular rashes and mucositis or stomatitis. All toxicities were reversible on treatment discontinuation. Maximum concentration and area under the concentration-time curve increase sub-proportionally with dose. Mean steady-state volume of distribution ranged from 127 to 385L. Sirolimus was a major metabolite (metabolite-to-parent ratio range, 2.5 to 3.5). Whole blood clearance was nonlinear, ranging from 19 to 51 L/h (34 to 220 mg/m(2)). Variability predicted with flat doses appears comparable with data based on body-surface area-normalized treatment. Partial responses were observed in one patient with renal clear-cell carcinoma and in one patient with breast adenocarcinoma.. CCI-779 displayed no immunosuppressive effects with manageable and reversible adverse events at doses up to 220 mg/m(2), the highest dose tested. Based on our results, weekly doses of 25, 75, and 250 mg CCI-779 not based on classical definitions of maximum-tolerated dose are being tested in phase II trials in patients with breast and renal cancer.

Topics: Adult; Antineoplastic Agents; Drug Administration Schedule; Enzyme Inhibitors; Female; Humans; Immunity; Infusions, Intravenous; Male; Middle Aged; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; Skin; TOR Serine-Threonine Kinases

Cardiac transplantation vasculopathy is the leading cause of late death in heart transplantation recipients. Rapamycin is an immunosuppressant drug with potent antiproliferative and antimigratory effects. We investigated whether rapamycin could prevent progression of graft vasculopathy in 46 patients (age, 54+/-10 years; 4.3+/-2.3 years after transplantation) with severe disease.. At annual cardiac catheterization, patients were randomly assigned to treatment with rapamycin (n=22) versus continued current immunosuppression (n=24). Clinical characteristics including recipient age and sex, underlying cause of congestive heart failure, donor age and sex, and ischemic time were recorded. Cardiac catheterization was graded with the use of a semiquantitative scale and repeated annually. Clinically significant adverse events were defined as death, need for angioplasty or bypass surgery, myocardial infarction, and a >25% worsening of the catheterization score. These events were monitored as primary study end points. Anti-HLA class I and II antibody production and lymphocyte growth assays were measured with each biopsy. Patients selected for rapamycin had azathioprine or mycophenolate mofetil discontinued and were given rapamycin. Outcomes were compared by means of log-rank analysis. There were no significant differences in baseline characteristics. Duration of follow-up was comparable (rapamycin, 689+/-261; control, 630+/-207 days; NS). In the rapamycin group, 3 patients reached primary end points versus 14 patients in the control group (P<0.001). There was no difference in baseline or subsequent anti-HLA class I or II antibody production.. In this patient cohort with cardiac vasculopathy, treatment with rapamycin slowed disease progression probably by its antiproliferative and antimigratory effects.

Topics: Arterial Occlusive Diseases; Autoantibodies; Cardiac Catheterization; Cohort Studies; Coronary Artery Disease; Cyclosporine; Disease Progression; Female; Graft Rejection; Heart Transplantation; Humans; Immunosuppressive Agents; Infections; Male; Middle Aged; Neoplasms; Prospective Studies; Renal Insufficiency; Sirolimus; Survival Analysis; Treatment Outcome

CCI-779 is a novel ester of the immunosuppressive agent sirolimus that exerts cytostatic effects by the inhibition of the translation of cell-cycle regulatory proteins. We investigated the maximum tolerated dose (MTD) and pharmacokinetics (PK) of CCI-779 in combination with leucovorin (LV) and 5-fluorouracil (5-FU) in patients with advanced solid tumors.. Patients were treated with LV at 200 mg/m(2) as a 1-h i.v. infusion directly followed by continuous 24-h i.v. infusion of 5-FU, in the first patient at 2000 mg/m(2) and in subsequent patients at 2600 mg/m(2). CCI-779 was administered directly prior to LV as a 30-min i.v. infusion at a starting dose of 15 mg/m(2) beginning at day 8 and escalated in subsequent cohorts of patients. One cycle consisted of six weekly administrations followed by 1 week of rest. Blood samples were drawn to assess PK of CCI-779 as well as its effect on steady-state 5-FU exposures.. Twenty-eight patients entered the study, the majority having tumor types for which 5-FU is used as a treatment. CCI-779 doses of 15, 25, 45 and 75 mg/m(2) were investigated. Skin toxicity (rash) was prominent at all dose levels examined. Stomatitis was the dose-limiting toxicity (DLT) for 75 mg/m(2) doses of CCI-779. Subsequently the cohort at 45 mg/m(2) was expanded to a total of 15 patients, and at this dose level two treatment-related deaths occurred due to mucositis with bowel perforation. Based on the toxicities observed, it was decided to discontinue the study. Partial responses were observed in three patients with gastrointestinal tumors. No pharmacokinetic interaction between CCI-779 and 5-FU was observed.. The safety profiles of CCI-779 and 5-FU/LV suggest an overlap of drug-related toxicities, and the administration of these drugs at these doses and schedule resulted in unacceptable toxicity and therefore cannot be recommended. If CCI-779 is to be used in combination with 5-FU/LV, other doses or schedules of administration will need to be explored.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Cell Cycle; Female; Fluorouracil; Humans; Infusions, Intravenous; Leucovorin; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Staging; Neoplasms; Sirolimus

Belatacept is employed alongside calcineurin inhibitor (CNI) therapy to prevent graft rejection in kidney transplant patients who are Epstein-Barr virus (EBV) seropositive. Preliminary data suggested that rates of post-transplant lymphoproliferative disorder (PTLD) were higher in individuals treated with belatacept compared to CNI therapy alone.. The records of 354 adults who underwent kidney only transplantation from January 2015 through September 2021 at one medical center were evaluated. Patients underwent treatment with either low-doses of mycophenolate, tacrolimus and sirolimus (B. Non-belatacept (MMF, tacrolimus and sirolimus) and belatacept-based (MMF, tacrolimus and belatacept) regimens do not appear to pose any increased risk of early onset PTLD. Both cohorts benefited from low rates of rejection, malignancy, mortality and graft failure. Recipients will continue to be monitored as PTLD can manifest as a long-term complication.

Topics: Abatacept; Adult; Calcineurin Inhibitors; Epstein-Barr Virus Infections; Graft Rejection; Graft Survival; Herpesvirus 4, Human; Humans; Immunosuppressive Agents; Kidney Transplantation; Lymphoproliferative Disorders; Neoplasms; Sirolimus; Tacrolimus

Upregulation of mechanistic target of rapamycin (mTOR) signaling drives various types of cancers and neurological diseases. Rapamycin and its analogues (rapalogs) are first generation mTOR inhibitors, and selectively block mTOR complex 1 (TORC1) by an allosteric mechanism. In contrast, second generation ATP-binding site inhibitors of mTOR kinase (TORKi) target both TORC1 and TORC2. Here, we explore 3,6-dihydro-2H-pyran (DHP) and tetrahydro-2H-pyran (THP) as isosteres of the morpholine moiety to unlock a novel chemical space for TORKi generation. A library of DHP- and THP-substituted triazines was prepared, and molecular modelling provided a rational for a structure activity relationship study. Finally, compound 11b [5-(4-(3-oxa-8-azabicyclo[3.2.1]octan-8-yl)-6-(tetrahydro-2H-pyran-4-yl)-1,3,5-triazin-2-yl)-4-(difluoromethyl)pyridin-2-amine] was selected due its potency and selectivity for mTOR kinase over the structurally related class I phosphoinositide 3-kinases (PI3Ks) isoforms. 11b displayed high metabolic stability towards CYP1A1 degradation, which is of advantage in drug development. After oral administration to male Sprague Dawley rats, 11b reached high concentrations both in plasma and brain, revealing an excellent oral bioavailability. In a metabolic stability assay using human hepatocytes, 11b was more stable than PQR620, the first-in-class brain penetrant TORKi. Compound 11b also displayed dose-dependent anti-proliferative activity in splenic marginal zone lymphoma (SMZL) cell lines as single agent and when combined with BCL2 inhibition (venetoclax). Our results identify the THP-substituted triazine core as a novel scaffold for the development of metabolically stable TORKi for the treatment of chronic diseases and cancers driven by mTOR deregulation and requiring drug distribution also to the central nervous system.

Topics: Animals; Humans; Male; Mechanistic Target of Rapamycin Complex 1; Morpholines; Neoplasms; Protein Kinase Inhibitors; Pyrans; Rats; Rats, Sprague-Dawley; Sirolimus; TOR Serine-Threonine Kinases

Rapamycin has great potential in the antitumor application, but its therapeutic effect is seriously affected by poor water solubility, targeting ability, and low bioavailability. Here, we constructed a novel composite nanomaterial with PCN-224 as a drug carrier and loaded rapamycin, named R@BP@HA. The nanoplate not only improves targeting, but also synergizes rapamycin with PCN-224 to effectively promote tumor cell apoptosis, which subsequently causes immunogenic cell death (ICD), and shows strong therapeutic effect in 4T1 breast cancer model. The treatment effect depends on three main points:(i)Proapoptotic effect of rapamycin on tumor cells;(ii)ROS production by PCN-224-mediated photodynamic therapy;(iii)ICD induced DC maturation, increased immune response and promoted T cell proliferation and differentiation. This nanoplate offers potential antitumor efficacy in combination with chemotherapy, photodynamic therapy, and immunotherapy.

Topics: Cell Line, Tumor; Humans; Immunogenic Cell Death; Immunotherapy; Metal-Organic Frameworks; Neoplasms; Sirolimus

Topics: Animals; Antineoplastic Agents; Apoptosis; Autophagy; Glycyrrhetinic Acid; Humans; Mice; Mice, Nude; Neoplasms; Sirolimus

The mechanistic target of rapamycin (mTOR) kinase is one of the top drug targets for promoting health and lifespan extension. Besides rapamycin, only a few other mTOR inhibitors have been developed and shown to be capable of slowing aging. We used machine learning to predict novel small molecules targeting mTOR. We selected one small molecule, TKA001, based on in silico predictions of a high on-target probability, low toxicity, favorable physicochemical properties, and preferable ADMET profile. We modeled TKA001 binding in silico by molecular docking and molecular dynamics. TKA001 potently inhibits both TOR complex 1 and 2 signaling in vitro. Furthermore, TKA001 inhibits human cancer cell proliferation in vitro and extends the lifespan of

Topics: Animals; Artificial Intelligence; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Proliferation; Humans; Longevity; Molecular Docking Simulation; MTOR Inhibitors; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Autophagy inducers increase the sensitivity of tumor cells to chemotherapeutic drugs and enhance anti-tumor efficacy. An autophagy-induced intracellular signaling fractional nano-drug system was constructed for the co-delivery of the autophagy inducer rapamycin (RAPA) and the anti-tumor drug 9-nitro-20(S)-camptothecin (9-NC). Link peptides, including cathepsin B-sensitive peptides (Ala-Leu-Ala-Leu, ALAL), nucleus-targeting peptides (TAT, sequence: YGRKKRRQRRR), and chrysin (CHR)-modified hydrophobic biodegradable polymers (poly(-caprolactone)) (PCL), were grafted onto hyaluronic acid (HA) to yield two amphiphiles, HA-ALAL-PCL-CHR (CPAH) and HA-ALAL-TAT-PCL-CHR (CPTAH). Spherical RAPA- and 9-NC-loaded micelles were obtained by the self-assembly of amphiphiles comprising CPAH and RAPA and CPTAH and 9-NC. In this fractional nano-drug system, RAPA was released earlier than 9-NC, as CPAH as a RAPA carrier lacked a nucleus-targeting TAT (unlike CPTAH as an 9-NC carrier). RAPA induced autophagy in tumor cells and improved their sensitivity, whereas the secondary nucleus-targeting micelles directly delivered 9-NC to the nucleus, considerably improving anti-tumor efficacy. Immunofluorescence staining, acridine orange (AO) staining, and western blotting results demonstrated that the system induced a high level of autophagy in combination chemotherapy. The proposed system possesses a high level of cytotoxicity in vitro and in vivo and provides a potential method for enhancing anti-tumor efficacy in clinical settings.

Topics: Antineoplastic Agents; Autophagy; Cell Line, Tumor; Drug Carriers; Humans; Micelles; Nanoparticles; Neoplasms; Peptides; Sirolimus

Mammalian target of rapamycin (mTOR) controls cellular anabolism, and mTOR signaling is hyperactive in most cancer cells. As a result, inhibition of mTOR signaling benefits cancer patients. Rapamycin is a US Food and Drug Administration (FDA)-approved drug, a specific mTOR complex 1 (mTORC1) inhibitor, for the treatment of several different types of cancer. However, rapamycin is reported to inhibit cancer growth rather than induce apoptosis. Pyruvate dehydrogenase complex (PDHc) is the gatekeeper for mitochondrial pyruvate oxidation. PDHc inactivation has been observed in a number of cancer cells, and this alteration protects cancer cells from senescence and nicotinamide adenine dinucleotide (NAD. 哺乳动物雷帕霉素靶蛋白（mTOR）控制细胞的合成代谢，并且在大多数的肿瘤细胞中mTOR信号通路高度活化，因此抑制mTOR信号通路对癌症患者有益。雷帕霉素是一种美国食品药品监督管理局（FDA）批准的临床一线药物，是mTORC1的特异性抑制剂，用于治疗多种不同类型的癌症。然而，研究发现雷帕霉素仅抑制肿瘤细胞的增殖并不引起细胞的凋亡。丙酮酸脱氢酶复合体（PDHc）在线粒体丙酮酸氧化过程起着决定作用。许多肿瘤细胞中的PDHc处于失活状态，这一变化可以使肿瘤细胞免于衰老和NAD

Topics: Dichloroacetic Acid; Humans; Mechanistic Target of Rapamycin Complex 1; Neoplasms; Pyruvate Dehydrogenase Complex; Sirolimus; TOR Serine-Threonine Kinases

Topics: Hemangioendothelioma; Humans; Kasabach-Merritt Syndrome; Neoplasms; Sarcoma, Kaposi; Sirolimus

mTORC1 is hyperactive in multiple cancer types

Topics: Endothelial Cells; Humans; Mechanistic Target of Rapamycin Complex 1; Midkine; Neoplasms; Neoplastic Stem Cells; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 2 Protein; Tumor Microenvironment; Tumor Suppressor Proteins

The mechanistic target of rapamycin (mTOR) plays a key role in normal and malignant cell growth. However, pharmacologic targeting of mTOR in cancer has shown little clinical benefit, in spite of aberrant hyperactivation of mTOR in most solid tumors. Here, we discuss possible reasons for the reduced clinical efficacy of mTOR inhibition and highlight lessons learned from recent combination clinical trials and approved indications of mTOR inhibitors in cancer. We also discuss how the emerging systems level understanding of mTOR signaling in cancer can be exploited for the clinical development of novel multimodal precision targeted therapies and immunotherapies aimed at achieving tumor remission.

Topics: Humans; Neoplasms; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

To utilize in silico-based approach for investigating the ability of PEGylated rapamycin as a competitive inhibitor to Galectin-3 for curing various diseases or that may provide an attractive strategy for treatment of a wide variety of tumors.. Galectin-3 (Gal-3) signaling protein is a unique member of lectin family present at the cell surface, intracellularly in both the nucleus and cytoplasm and extracellularly in the general circulation. Circulating Gal-3 is present in both normal and cancer cells. High levels of circulating Gal-3 have been proven to be associated with inflammation and fibrosis in several acute and chronic conditions, which include neurological degeneration, inflammatory and immune responses, autoimmune diseases, diabetes, heart failure, atherosclerosis, response to infection, wound healing, liver, lung, and kidney disease. Gal-3 is known to regulate many biological activities including cell adhesion, angiogenesis, growth, apoptosis, migration, and metastasis. Rapamycin has been examined alone or in combination with other drugs for treatment of various cancers in clinical studies. Although it has shown promising therapeutic effects, its clinical development was interrupted by poor aqueous solubility and limited preferential distribution. To overcome these limitations, RA has been chemically modified to hydrophilic analogues, such as everolimus (EV). However, all these approaches can only partially increase the solubility, but has little effect on the blood distribution and pharmacokinetics. Therefore, it is necessary to explore other RA conjugates to improve aqueous solubility and tissue distribution profile. Recently we reported that RP-MPEG inhibits the growth of various cancer cell lines by acting on mammalian target of RP (mTOR) receptor site and it can be used for gastric cancer.. To construct various molecular weight RP-MPEG by replacing MPEG chain in 40-O-(2- hydroxyethyl) position of the EV and analyze their binding affinity to Gal-3.. The chemical structures of various molecular weight RP-MPEG were built using ChemSketch software. The molecular docking study was performed to find the best probable structure of RP-MPEG for competitive inhibition of the CRD, based on the interaction score. For that purpose, the 3D structures of RP and EV were obtained from NCBI PubChem compound database, where the structural protein-co-crystallized ligand complex of Gal-3 (TD2, as a native ligand) was retrieved from RCSB Protein Data Bank. All structures of the selected compounds, served as molecules for molecular modeling, were optimized through MOE.2014 software before docking. Hydrogen atoms and partial charges were added to the protein. Protein minimization was performed in gas solvation with the side chains, keeping it rigid and the ligand flexible. The selected site was isolated and minimized, followed by protonating the protein. The 3D ligands were minimized using MMFF94x with cutoffs of 10 to 12 Å. The hydrogens and charges were fixed, and the RMS gradient was set to 0.001 kcal/mol. The docking results were analyzed to identify and assess the binding affinity of these compounds to CRD using drug discovery software.. Our results indicated that RP-MPEG with MW 1178.51 g/mol has a logP value of 3.79 and has possessed the strongest binding affinity toward CRD of Gal-3 with a docking score of -6.87. Compared with TD2, there were additional close contacts for RP-MPEG (MW 1178.51 g/mol), coming from three hydrogen bonds with Asp148, Arg162, and Arg144 which suggest that this ligand is a strong competitive inhibitor among the other molecules for Gal-3.. RP-MPEG with the MW 1178.51 g/mol could be a promising blocker for various biological action of Gal-3 includes profibrotic activity, modulation of immune responses and inflammatory responses to cancer that contributes to neoplastic transformation, angiogenesis and metastasis. Other: The 95% confidence intervals (CIs) of the binding affinity (according to their mean and standard errors) were estimated with 2.5 and 97.5 percentile as the lower and upper bounds.

Topics: Antibiotics, Antineoplastic; Blood Proteins; Galectins; Humans; Molecular Docking Simulation; Molecular Weight; Neoplasms; Polyethylene Glycols; Protein Binding; Sirolimus

Topics: Combined Modality Therapy; Hidradenitis Suppurativa; Humans; Necrosis; Neoplasms; Sirolimus; Tumor Necrosis Factor-alpha

Topics: Hidradenitis Suppurativa; Humans; Necrosis; Neoplasms; Sirolimus; Tumor Necrosis Factor-alpha

Immunosuppressive-drugs are needed after solid organ transplantation to prevent allograft rejection but induce severe side effects. Understanding the alloimmune response is critical to modulate it and to achieve graft operational tolerance. The role of regulatory T cells and tolerogenic dendritic cells (Tol-DCs) is undoubtedly essential in tolerance induction. Tacrolimus is considered as the cornerstone of immunosuppression in solid organ transplantation. mTOR inhibitor such as rapamycin are thought to induce tolerance and are used as anticancer drugs in several cancers. The aim of this study was to better understand the effect of these immunosuppressive drugs on the differentiation, maturation and function of human monocyte derived dendritic cells (DCs).. DCs were differentiated from monocytes of healthy donors with either rapamycin (Rapa-DCs) or tacrolimus (Tac-DCs). The phenotype was evaluated by flow cytometry analysis. The production of pro- and anti-inflammatory cytokines was assessed by ELISA. The mRNA expression level of IDO and PD-L1 was assessed by RTqPCR. Mixed leukocytes reactions were performed to analyse suppressive activity of DCs.. Rapa-DC were characterised by a lower expression of the co-stimulatory molecules and CD83 than control-DCs (CTR-DC) (p < 0.05). In contrast, tacrolimus had no effect on the expression of surface markers compared to CTR-DCs. Rapamycin reduced both IL-12 and IL-10 secretions (p < 0.05). Rapa-DCs had a suppressive effect on CD4. Rapa-DCs exhibit an incomplete phenotypic tolerogenic profile. To our knowledge this is the first paper showing a reduction of expression of pro-tolerogenic enzyme IDO in DCs. Tacrolimus does not change the phenotypical or functional characteristics of moDCs.

Topics: B7-H1 Antigen; Cell Differentiation; Cells, Cultured; Cytokines; Dendritic Cells; Forkhead Transcription Factors; Healthy Volunteers; Humans; Immune Tolerance; Immunomodulation; Immunosuppressive Agents; Indoleamine-Pyrrole 2,3,-Dioxygenase; Inflammation Mediators; Monocytes; Neoplasms; Organ Transplantation; Phenotype; Sirolimus; T-Lymphocytes, Regulatory; Tacrolimus

Here, we showed that the acetylation-defective

Topics: Acetylation; Animals; Carcinogenesis; Cell Cycle Checkpoints; Embryo, Mammalian; Lysine; Mice; Mutation; Neoplasms; Proto-Oncogene Proteins c-mdm2; Sirolimus; Survival Analysis; TOR Serine-Threonine Kinases; Tumor Suppressor Protein p53

The introduction of mammalian target of rapamycin inhibitors (mTORi) as immunosuppressive agents has changed the landscape of calcineurin inhibitor-based immunosuppressive regimens. However, the timing of mTORi conversion and its associated outcomes in kidney transplantation have conflicting results. This study investigated the effect of early or late mTORi post-transplant initiation on major transplant outcomes, including post-transplant malignancy, in kidney transplant recipients in our center. We enrolled 201 kidney transplant recipients with surviving function grafts of >3 months between 1983 and 2016. Patients were divided into three groups: early mTORi (initiated within 6 months of kidney transplantation), late mTORi, (mTORi initiation >6 months after kidney transplantation) and no mTORi. The mean creatinine at conversion was 1.46 ± 0.48 mg/dL and 1.30 ± 0.53 mg/dL for the early and late mTORi groups, respectively. During the study period, 10.5% of mTORi users and 19.2% of mTORi nonusers developed malignancy, mainly urothelial carcinoma. After adjustment for confounding factors, mTORi users were found to have a lower incidence of post-transplant malignancy than did nonusers (adjusted OR: 0.28,

Topics: Adult; Antineoplastic Agents; Calcineurin Inhibitors; Everolimus; Female; Graft Rejection; Humans; Immunocompromised Host; Immunosuppressive Agents; Incidence; Kidney Transplantation; Male; Middle Aged; Neoplasms; Retrospective Studies; Risk Factors; Sirolimus; Time-to-Treatment; TOR Serine-Threonine Kinases; Treatment Outcome

Vascular malformations are thought to be monogenic disorders that result in dysregulated growth of blood vessels. In the brain, cerebral cavernous malformations (CCMs) arise owing to inactivation of the endothelial CCM protein complex, which is required to dampen the activity of the kinase MEKK3

Topics: Animals; Animals, Newborn; Class I Phosphatidylinositol 3-Kinases; Disease Models, Animal; Endothelial Cells; Gain of Function Mutation; Hemangioma, Cavernous, Central Nervous System; Humans; Kruppel-Like Factor 4; Kruppel-Like Transcription Factors; Loss of Function Mutation; Male; MAP Kinase Kinase Kinase 3; Mechanistic Target of Rapamycin Complex 1; Mice; Mutation; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

The Warburg effect has been considered a potential therapeutic target to fight against cancer progression. In KRAS mutant cells, PKM2 (pyruvate kinase isozyme M2) is hyper-activated, and it induces GLUT1 expression; therefore, KRAS has been closely involved in the initiation of Warburg metabolism. Although mTOR (mammalian target of rapamycin), a well-known inhibitor of autophagy-dependent survival in physiological conditions, is also activated in KRAS mutants, many recent studies have revealed that autophagy becomes hyper-active in KRAS mutant cancer cells. In the present study, a mathematical model was built containing the main elements of the regulatory network in KRAS mutant cancer cells to explore the further possible therapeutic strategies. Our dynamical analysis suggests that the downregulation of KRAS, mTOR and autophagy are crucial in anti-cancer therapy. PKM2 has been assumed to be the key switch in the stress response mechanism. We predicted that the addition of both pharmacologic ascorbate and chloroquine is able to block both KRAS and mTOR pathways: in this case, no GLUT1 expression is observed, meanwhile autophagy, essential for KRAS mutant cancer cells, is blocked. Corresponding to our system biological analysis, this combined pharmacologic ascorbate and chloroquine treatment in KRAS mutant cancers might be a therapeutic approach in anti-cancer therapies.

Topics: Antineoplastic Agents; Autophagy; Chloroquine; Models, Theoretical; Neoplasms; Proto-Oncogene Proteins p21(ras); Pyruvate Kinase; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Warburg Effect, Oncologic

Although the polymeric vascular disrupting agent (poly(l-glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4) nanoparticles (CA4-NPs) has great potential to inhibit cancer growth, it is still a challenge to avert tumor recurrence and metastasis after treatment. It is mainly tightly associated with hypoxia induced by CA4-NPs, which can activate many downstream genes regulating tumor growth and metastasis. Herein, to relieve a tumor hypoxia microenvironment, the mTOR inhibitor temsirolimus was employed to modulate the tumor microenvironment when treated with CA4-NPs. In vitro MTT experiments strongly verified that the combination of temsirolimus with polymeric CA4-NPs exhibited an additive toxicity to 4T1 cells. An in vivo study with the 4T1 mammary adenocarcinoma model revealed that consistent with the proposed scenario, combination therapy with CA4-NPs plus temsirolimus suppressed tumor growth significantly more strongly compared to either CA4-NPs or temsirolimus monotherapy, and the inhibition rate to 4T1 tumor with a volume of 300 mm

Topics: Animals; Cell Hypoxia; Cell Line, Tumor; Cell Survival; Down-Regulation; Drug Synergism; Female; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Mice, Inbred BALB C; Nanoparticles; Neoplasm Metastasis; Neoplasms; Polyethylene Glycols; Polyglutamic Acid; Polymers; Sirolimus; Stilbenes; Tumor Microenvironment

A number of mammalian target of rapamycin (mTOR) inhibitors have been approved for the treatment of certain types of cancer or are currently undergoing clinical trials. However, mTOR targeted therapy exerts selective pressure on tumour cells, which leads to the preferential growth of resistant subpopulations. There are two classes of mTOR inhibitors: i) The rapalogs, such as rapamycin, which bind to the 12‑kDa FK506‑binding protein/rapamycin‑binding domain of mTOR; and ii) the ATP‑competitive inhibitors, such as AZD8055, which block the mTOR kinase domain. Cardamonin inhibits mTOR by decreasing the expression of regulatory‑associated protein of mTOR (Raptor), a mechanism of action which differs from the currently available mTOR inhibitors. The present study investigated the inhibitory effects of cardamonin on mTOR inhibitor‑resistant cancer cells. HeLa cervical cancer cells and MCF‑7 breast cancer cells were exposed to high concentrations of mTOR inhibitors, until resistant clones emerged. Cytotoxicity was measured using the MTT and colony forming assays. The inhibitory effect of cardamonin on mTOR signalling was assessed by western blotting. The resistant cells were less sensitive to mTOR inhibitors compared with the parental cells. Consistent with the anti‑proliferation effect, rapamycin and AZD8055 had no effect on the phosphorylation of rapamycin‑sensitive sites on ribosomal protein S6 kinase B1 (S6K1) and AZD8055‑sensitive sites on protein kinase B and eukaryotic translation initiation factor 4E binding protein 1 (Thr 37/46), respectively, in rapamycin‑ and AZD8055‑resistant cells. Cardamonin inhibited cell proliferation and decreased the phosphorylation of mTOR and S6K1, as well as the protein level of raptor, in the mTOR inhibitor‑resistant cells. Therefore, cardamonin may serve as a therapeutic agent for patients with cervical and breast cancer resistant to mTOR inhibitors.

Topics: Cell Proliferation; Chalcones; Drug Resistance, Neoplasm; HeLa Cells; Humans; MCF-7 Cells; Morpholines; Neoplasm Proteins; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Telomerase deficiency leads to age-related diseases and shorter lifespans. Inhibition of the mechanistic target of rapamycin (mTOR) delays aging and age-related pathologies. Here, we show that telomerase deficient mice with short telomeres (G2-Terc

Topics: Aging; Animals; DNA Damage; Female; Longevity; Male; Mice, Inbred C57BL; Mice, Knockout; Neoplasms; Phosphorylation; Ribosomal Protein S6 Kinases, 90-kDa; RNA; Sirolimus; Survival Rate; Telomerase; Telomere; TOR Serine-Threonine Kinases

Rapalogs have become standard-of-care in patients with metastatic breast, kidney, and neuroendocrine cancers. Nevertheless, tumor escape occurs after several months in most patients, highlighting the need to understand mechanisms of resistance. Using a panel of cancer cell lines, we show that rapalogs downregulate the putative protein kinase TRIB3 (tribbles pseudokinase 3). Blood samples of a small cohort of patients with cancer treated with rapalogs confirmed downregulation of TRIB3. Downregulation of TRIB3 was mediated by LRRFIP1 independently of mTOR and disrupted its interaction with the spliceosome, where it participated in rapalog-induced deregulation of RNA splicing. Conversely, overexpression of TRIB3 in a panel of cancer cell lines abolished the cytotoxic effects of rapalogs. These findings identify TRIB3 as a key component of the spliceosome, whose repression contributes significantly to the mechanism of resistance to rapalog therapy. SIGNIFICANCE: Independent of mTOR signaling, rapalogs induce cytoxicity by dysregulating spliceosome function via repression of TRIB3, the loss of which may, in the long term, contribute to therapeutic resistance.

Topics: Antineoplastic Agents; Cell Cycle Proteins; Cell Line, Tumor; Down-Regulation; Everolimus; Gene Expression; Humans; MCF-7 Cells; Neoplasms; Promoter Regions, Genetic; Protein Serine-Threonine Kinases; Repressor Proteins; RNA Splicing; RNA-Binding Proteins; Sirolimus; TOR Serine-Threonine Kinases

As a rapid proliferating tissue, tumor cells have to optimize nutrient utilization to withstand harsh conditions. Several approaches have been explored to inhibit the growth and metastasis of tumor by disrupting the reprogrammed tumor metabolism. However, nutrient limitations within solid tumors may induce the metabolic flexibility of malignant cells to sustain growth and survival using one nutrient to fill metabolite pools normally supplied by the other. To overcome this predicament, a promising click-nucleic-acid-containing platform for codelivery of rapamycin, anti-PFKFB4 siRNA, and targeting ligand aptamer AS1411 was applied. PFKFB4 could act as a promising target for tumor therapy for being a molecular fulcrum that could couple glycolysis to autophagy by promoting aggressive metastatic tumors. The downregulation of PFKFB4 can help inhibit the SRC3/Akt/mTOR pathway, leading autophagy to the direction of promoting apoptosis of tumor cells, which is induced by the collapse of tumor cellular homeostasis, while low dosages of rapamycin could decrease surgery-induced immune dysfunction. Enhanced tumor autophagy, favorable in vivo antitumor efficacy, and effective systematic immune activation are observed after treatment, suggesting that autophagy and glycolysis can serve as an integrated target for tumor treatment.

Topics: Animals; Aptamers, Nucleotide; Autophagy; Base Sequence; Drug Carriers; Glycolysis; HEK293 Cells; Homeostasis; Humans; Hydrophobic and Hydrophilic Interactions; Mice; Nanoparticles; Neoplasms; Phosphofructokinase-2; Poly T; Polyethylene Glycols; Polylactic Acid-Polyglycolic Acid Copolymer; RNA, Small Interfering; Sirolimus

Signal integration has a crucial role in the cell fate decision and dysregulation of the cellular signaling pathways is a primary characteristic of cancer. As a signal integrator, mTOR shows a complex dynamical behavior which determines the cell fate at different cellular processes levels, including cell cycle progression, cell survival, cell death, metabolic reprogramming, and aging. The dynamics of the complex responses to rapamycin in cancer cells have been attributed to its differential time-dependent inhibitory effects on mTORC1 and mTORC2, the two main complexes of mTOR. Two explanations were previously provided for this phenomenon: 1-Rapamycin does not inhibit mTORC2 directly, whereas it prevents mTORC2 formation by sequestering free mTOR protein (Le Chatelier's principle). 2-Components like Phosphatidic Acid (PA) further stabilize mTORC2 compared with mTORC1. To understand the mechanism by which rapamycin differentially inhibits the mTOR complexes in the cancer cells, we present a mathematical model of rapamycin mode of action based on the first explanation, i.e., Le Chatelier's principle. Translating the interactions among components of mTORC1 and mTORC2 into a mathematical model revealed the dynamics of rapamycin action in different doses and time-intervals of rapamycin treatment. This model shows that rapamycin has stronger effects on mTORC1 compared with mTORC2, simply due to its direct interaction with free mTOR and mTORC1, but not mTORC2, without the need to consider other components that might further stabilize mTORC2. Based on our results, even when mTORC2 is less stable compared with mTORC1, it can be less inhibited by rapamycin.

Topics: Humans; Kinetics; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Models, Biological; Neoplasms; Signal Transduction; Sirolimus; Time Factors; TOR Serine-Threonine Kinases

Topics: Antineoplastic Agents; Autophagy; Everolimus; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Chimeric antigen receptor (CAR) T cell therapies have achieved promising outcomes in several cancers, however more challenging oncology indications may necessitate advanced antigen receptor designs and functions. Here we describe a bipartite receptor system comprised of separate antigen targeting and signal transduction polypeptides, each containing an extracellular dimerization domain. We demonstrate that T cell activation remains antigen dependent but can only be achieved in the presence of a dimerizing drug, rapamycin. Studies performed in vitro and in xenograft mouse models illustrate equivalent to superior anti-tumor potency compared to currently used CAR designs, and at rapamycin concentrations well below immunosuppressive levels. We further show that the extracellular positioning of the dimerization domains enables the administration of recombinant re-targeting modules, potentially extending antigen targeting. Overall, this novel regulatable CAR design has exquisite drug sensitivity, provides robust anti-tumor responses, and is uniquely flexible for multiplex antigen targeting or retargeting, which may further assist the development of safe, potent and durable T cell therapeutics.

Topics: Animals; Antigens, CD19; Cell Line, Tumor; Female; Humans; Immunotherapy, Adoptive; Lymphocyte Activation; Mice; Neoplasms; Promoter Regions, Genetic; Protein Domains; Protein Multimerization; Receptors, Chimeric Antigen; Recombinant Fusion Proteins; Single-Chain Antibodies; Sirolimus; T-Lymphocytes; Xenograft Model Antitumor Assays

Malignancy is a major cause of late post-heart transplantation (HT) mortality. Sirolimus (SRL) exerts antiproliferative properties and its long-term use in HT as primary immunosuppression (IS) is associated with decreased mortality risk that is not fully explained by attenuation of cardiac allograft vasculopathy progression.. This study sought to examine whether conversion from calcineurin inhibitor (CNI)-based to SRL-based IS was associated with decreased risk of malignancy post-HT.. Overall, 523 patients underwent HT between 1994 and 2016 at a single institution. The main outcomes included incidence of overall de novo malignancies (excluding non-melanoma skin cancers [NMSCs]), post-transplantation lymphoproliferative disorders (PTLD), and first and subsequent primary occurrences of NMSC post-HT.. The study identified 307 patients on SRL-based and 216 on CNI-based maintenance IS. Over a median follow-up of 10 years after HT, overall de novo malignancies (non-NMSC) occurred in 31% of CNI patients and in 13% of SRL patients (adjusted hazard ratio [HR]: 0.34; 95% confidence interval [CI]: 0.18 to 0.62; p < 0.001). The incidence of the first NMSC was similar in the SRL and CNI groups (HR: 0.92; 95% CI: 0.66 to 1.28; p = 0.62). However, conversion to SRL was significantly associated with a decreased risk of subsequent primary occurrences of NMSC compared with that of CNI (adjusted HR: 0.44; 95% CI: 0.28 to 0.69; p < 0.001). The adjusted PTLD risk was significantly decreased in the SRL group (HR: 0.13; 95% CI: 0.03 to 0.59; p = 0.009). Late survival post-HT was markedly decreased in patients who developed non-NMSC, PTLD, or non-PTLD compared with patients who did not develop these malignancies, whereas NMSC had no significant effect on survival.. Conversion to SRL was associated with a decreased risk of all de novo malignancies, PTLD, and subsequent primary occurrences of NMSC after HT. These findings provided further explanation of the late survival benefit with long-term SRL use.

Topics: Adult; Aged; Calcineurin Inhibitors; Female; Heart Transplantation; Humans; Immunosuppressive Agents; Incidence; Male; Middle Aged; Minnesota; Neoplasms; Retrospective Studies; Sirolimus; Skin Neoplasms

Topics: Heart Transplantation; Humans; Immunosuppression Therapy; Incidence; Neoplasms; Sirolimus

The involvement of mammalian target of rapamycin (mTOR) in the positive regulation of oncogenesis has been well documented and thus mTOR has emerged as an attractive cancer therapeutic target. Although rapamycin and its analogues (rapalogs) are FDA-approved for the treatment of certain cancers, major success in targeting mTOR, particularly with new generation mTOR kinase inhibitors, for the effective treatment of cancers has not been achieved. Hence, a thorough understanding of the biology of the mTOR axis in cancer is still needed. It is now recognized that programmed death-ligand 1 (PD-L1) expression on cancer cells is a critical mechanism contributing to immunosuppression and immune escape via interacting with program death-1 (PD-1) on immune cells. This study has revealed a previously undiscovered role of the mTOR complex 1 (mTORC1)/p70 S6 kinase (p70S6K) in the negative regulation of PD-L1 on cancer cells and tissues. We demonstrate that disruption of this signaling pathway with mTOR inhibitors, raptor knockdown or p70S6K inhibitors elevated PD-L1 levels in some lung and other cancer cell lines. Elevation of PD-L1 by inhibition of mTORC1/p70S6K signaling is likely due to suppression of β-TrCP-mediated proteasomal degradation of PD-L1, because inhibition of either mTORC1 or p70S6K facilitated β-TrCP degradation accompanied with enhanced PD-L1 protein stabilization. Our current findings indicate the complexity of the mTOR axis in cancer, which should be considered when targeting this axis for effective cancer treatment. Our findings also suggest a strong scientific rationale for enhancing PD-1/PD-L1-targeted cancer immunotherapy through co-targeting mTORC1/p70S6K signaling.

Topics: A549 Cells; B7-H1 Antigen; Benzoxazoles; beta-Transducin Repeat-Containing Proteins; Cycloheximide; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; HCT116 Cells; HEK293 Cells; Humans; Leupeptins; MCF-7 Cells; Mechanistic Target of Rapamycin Complex 1; Morpholines; Naphthyridines; Neoplasms; Protein Stability; Pyrimidines; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; Tumor Cells, Cultured

Topics: Antineoplastic Agents; Apoptosis; Cell Cycle; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Drug Design; Drug Screening Assays, Antitumor; Humans; Neoplasms; Pyrimidinones; TOR Serine-Threonine Kinases

Resistance to a drug and the suppression of inflammatory disorders with immunosuppressive drugs might have happened upon exposure to natural compounds during evolution. Streptomycetes are soil bacteria, but they produce therapeutic drugs. They have been reported to be the low-abundant members of mucosal microbiomes with a higher prevalence in nonhumans ingesting soil compared with humans. Their lower abundance in the human microbiome might be the representations of our current hygienic lifestyle. We suggest that the Streptomyces bacteria producing antiproliferative/immunosuppressive compounds (e.g., rapamycin and tacrolimus) contribute to the rapalog resistance of certain mucosal tumours (e.g., colon cancer) and the 'hygiene hypothesis'. If so, the shortage of exposure to these compounds in the current lifestyle might be an underlying reason for the increase of inflammatory diseases, such as inflammatory bowel diseases (IBD). An investigation on adding certain Streptomycetes (e.g., S. hygroscopicus and S. tubercidicus) to the list of probiotics against inflammatory diseases would be an interesting research area in the future.

Topics: Biological Evolution; Drug Resistance; Humans; Hygiene Hypothesis; Immunosuppressive Agents; Neoplasms; Sirolimus; Streptomyces; Tacrolimus

NK cell-based immunotherapies have been gaining traction in the clinic for treatment of cancer. IL-15 is currently being used in number of clinical trials to improve NK cell expansion and function. The objective of this study is to evaluate the effect of repetitive IL-15 exposure on NK cells. An in vitro model in which human NK cells are continuously (on on on) or intermittently (on off on) treated with IL-15 was used to explore this question. After treatment, cells were evaluated for proliferation, survival, cell cycle gene expression, function, and metabolic processes. Our data indicate that continuous treatment of NK cells with IL-15 resulted in decreased viability and a cell cycle arrest gene expression pattern. This was associated with diminished signaling, decreased function both in vitro and in vivo, and reduced tumor control. NK cells continuously treated with IL-15 also displayed a reduced mitochondrial respiration profile when compared with NK cells treated intermittently with IL-15. This profile was characterized by a decrease in the spare respiratory capacity that was dependent on fatty acid oxidation (FAO). Limiting the strength of IL-15 signaling via utilization of an mTOR inhibitor rescued NK cell functionality in the group continuously treated with IL-15. The findings presented here show that human NK cells continuously treated with IL-15 undergo a process consistent with exhaustion that is accompanied by a reduction in FAO. These findings should inform IL-15-dosing strategies in NK cell cancer immunotherapeutic settings.

Topics: Animals; Blood Buffy Coat; Cell Line, Tumor; Clinical Trials as Topic; Fatty Acids; Humans; Immunotherapy; Interleukin-15; Killer Cells, Natural; Mice; Neoplasms; Oxidation-Reduction; Recombinant Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Whole-Body Irradiation; Xenograft Model Antitumor Assays

Cancer Tissue Heterogeneity is an important consideration in cancer research as it can give insights into the causes and progression of cancer. It is known to play a significant role in cancer cell survival, growth and metastasis. Determining the compositional breakup of a heterogeneous cancer tissue can also help address the therapeutic challenges posed by heterogeneity. This necessitates a low cost, scalable algorithm to address the challenge of accurate estimation of the composition of a heterogeneous cancer tissue.. In this paper, we propose an algorithm to tackle this problem by utilizing the data of accurate, but high cost, single cell line cell-by-cell observation methods in low cost aggregate observation method for heterogeneous cancer cell mixtures to obtain their composition in a Bayesian framework.. The algorithm is analyzed and validated using synthetic data and experimental data. The experimental data is obtained from mixtures of three separate human cancer cell lines, HCT116 (Colorectal carcinoma), A2058 (Melanoma) and SW480 (Colorectal carcinoma).. The algorithm provides a low cost framework to determine the composition of heterogeneous cancer tissue which is a crucial aspect in cancer research.

Topics: Algorithms; Antineoplastic Agents; Bayes Theorem; Cell Count; Cell Line, Tumor; Computer Simulation; Humans; Lapatinib; Neoplasms; Probability; Sirolimus

The urea cycle (UC) is the main pathway by which mammals dispose of waste nitrogen. We find that specific alterations in the expression of most UC enzymes occur in many tumors, leading to a general metabolic hallmark termed "UC dysregulation" (UCD). UCD elicits nitrogen diversion toward carbamoyl-phosphate synthetase2, aspartate transcarbamylase, and dihydrooratase (CAD) activation and enhances pyrimidine synthesis, resulting in detectable changes in nitrogen metabolites in both patient tumors and their bio-fluids. The accompanying excess of pyrimidine versus purine nucleotides results in a genomic signature consisting of transversion mutations at the DNA, RNA, and protein levels. This mutational bias is associated with increased numbers of hydrophobic tumor antigens and a better response to immune checkpoint inhibitors independent of mutational load. Taken together, our findings demonstrate that UCD is a common feature of tumors that profoundly affects carcinogenesis, mutagenesis, and immunotherapy response.

Topics: Amino Acid Transport Systems, Basic; Animals; Aspartate Carbamoyltransferase; Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing); Cell Line, Tumor; Dihydroorotase; Female; Genomics; Humans; Metabolomics; Mice; Mice, Inbred C57BL; Mice, SCID; Mitochondrial Membrane Transport Proteins; Neoplasms; Ornithine Carbamoyltransferase; Phosphorylation; Pyrimidines; RNA Interference; RNA, Small Interfering; Sirolimus; TOR Serine-Threonine Kinases; Urea

The mechanistic target of rapamycin (mTOR) serine/threonine kinase, a critical regulator of cell proliferation, is frequently deregulated in human cancer. Although rapamycin inhibits the two canonical mTOR complexes, mTORC1 and mTORC2, it often shows minimal benefit as an anticancer drug. This is caused by rapamycin resistance of many different tumors, and we show that a third mTOR complex, mTORC3, contributes to this resistance. The ETS (E26 transformation-specific) transcription factor ETV7 interacts with mTOR in the cytoplasm and assembles mTORC3, which is independent of ETV7's transcriptional activity. This complex exhibits bimodal mTORC1/2 activity but is devoid of crucial mTORC1/2 components. Many human cancers activate mTORC3 at considerable frequency, and tumor cell lines that lose mTORC3 expression become rapamycin-sensitive. We show mTORC3's tumorigenicity in a rhabdomyosarcoma mouse model in which transgenic ETV7 expression accelerates tumor onset and promotes tumor penetrance. Discovery of mTORC3 represents an mTOR paradigm shift and identifies a novel target for anticancer drug development.

Topics: Animals; B-Lymphocytes; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Mechanistic Target of Rapamycin Complex 1; Mice, Inbred C57BL; Mice, Knockout; Neoplasms; Proto-Oncogene Proteins c-ets; Rapamycin-Insensitive Companion of mTOR Protein; Regulatory-Associated Protein of mTOR; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

Mammalian target of rapamycin (mTOR) is a PI3K-related serine/threonine protein kinase that functions as a master regulator of cellular growth and metabolism, in response to nutrient and hormonal stimuli. mTOR functions in two distinct complexes-mTORC1 is sensitive to rapamycin, while, mTORC2 is insensitive to this drug. Deregulation of mTOR's enzymatic activity has roles in cancer, obesity, and aging. Rapamycin and its chemical derivatives are the only drugs that inhibit the hyperactivity of mTOR, but numerous side effects have been described due to its therapeutic use. The purpose of this study was to identify new compounds of natural origin that can lead to drugs with fewer side effects. We have used computational techniques (molecular docking and calculated ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) parameters) that have enabled the selection of candidate compounds, derived from marine natural products, SuperNatural II, and ZINC natural products, for inhibitors targeting, both, the ATP and the rapamycin binding sites of mTOR. We have shown experimental evidence of the inhibitory activity of eleven selected compounds against mTOR. We have also discovered the inhibitory activity of a new marine extract against this enzyme. The results have been discussed concerning the necessity to identify new molecules for therapeutic use, especially against aging, and with fewer side effects.

Topics: Aquatic Organisms; Biological Products; Cell Line, Tumor; HCT116 Cells; Humans; Molecular Docking Simulation; Neoplasms; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases

DDIT4 gene encodes a protein whose main action is to inhibit mTOR under stress conditions whilst several in vitro studies indicate that its expression favors cancer progression. We have previously described that DDIT4 expression is an independent prognostic factor for tripe negative breast cancer resistant to neoadjuvant chemotherapy. We herein report that high DDIT4 expression is related to the outcome (recurrence-free survival, time to progression and overall survival) in several cancer types. We performed in silico analysis in online platforms, in pooled datasets from KM Plotter and meta-analysis of individual datasets from SurvExpress. High levels of DDIT4 were significantly associated with a worse prognosis in acute myeloid leukemia, breast cancer, glioblastoma multiforme, colon, skin and lung cancer. Conversely, a high DDIT4 expression was associated with an improved prognostic in gastric cancer. DDIT4 was not associated with the outcome of ovarian cancers. Analysis with data from the Cell Miner Tool in 60 cancer cell lines indicated that although rapamycin activity was correlated with levels of MTOR, it is not influenced by DDIT4 expression. In summary, DDIT4 might serve as a novel prognostic biomarker in several malignancies. DDIT4 activity could be responsible for resistance to mTOR inhibitors and is a potential candidate for the development of targeted therapy.

Topics: Biomarkers, Tumor; Computer Simulation; Databases as Topic; DNA Damage; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Prognosis; Signal Transduction; Sirolimus; Survival Analysis; TOR Serine-Threonine Kinases; Transcription Factors; Treatment Outcome

Balanced deoxyribonucleotides pools are essential for cell survival and genome stability. Ribonucleotide reductase is the rate-limiting enzyme for the production of deoxyribonucleotides. We report here that p53 suppresses ribonucleotide reductase subunit 1 (RRM1) and 2 (RRM2) via inhibiting mammalian target of rapamycin complex 1 (mTORC1). In vitro, cancer cell lines and mouse embryonic fibroblast cells were treated with different concentrations of pharmacological inhibitors for different times. In vivo, rhabdomyosarcoma Rh30 cell tumor-bearing mice were treated with rapamycin or AZD8055. Protein levels and phosphorylation status were assessed by immunoblotting and mRNA levels were determined by real time RT-PCR. Pharmacological inhibition of mTORC1 with rapamycin, mTOR kinase with AZD8055 or protein kinase B with MK2206 resulted in decrease of RRM1 and RRM2 in Rh30 cells both in vitro and in mouse tumor xenografts. Moreover, eukaryotic translational initiation factor 4E-binding proteins 1 and 2 double knockout mouse embryonic fibroblast cells demonstrated an elevation of RRM1 and RRM2. Furthermore, down-regulation of mTOR-protein kinase B signaling or cyclin dependent kinase 4 led to decrease of RRM1 and RRM2 mRNAs. In addition, TP53 mutant cancer cells had elevation of RRM1 and RRM2, which was reduced by rapamycin. Importantly, human double minute 2 inhibitor nutlin-3 decreased RRM1 and RRM2 in TP53 wild type rhabdomyosarcoma Rh18 but not in TP53 mutated Rh30 cells. Our data demonstrated that mTOR enhances the cap-dependent protein translation and gene transcription of RRM1 and RRM2. Our findings might provide an additional mechanism by which p53 maintains genome stability.

Topics: A549 Cells; Animals; Cell Line, Tumor; Cells, Cultured; Gene Expression Regulation, Neoplastic; Heterocyclic Compounds, 3-Ring; Humans; Mechanistic Target of Rapamycin Complex 1; Mice, Knockout; Mice, SCID; Morpholines; Mutation; Neoplasms; Ribonucleoside Diphosphate Reductase; RNA Interference; Sirolimus; Tumor Suppressor Protein p53; Tumor Suppressor Proteins; Xenograft Model Antitumor Assays

Nano-graphene oxide (nGO) is a carbon allotrope studied for its potential as carrier for chemotherapeutic delivery and its photoablation effects. However, interaction of nGO with blood components and the subsequent toxicities warrant a hybrid system for effective cancer drug delivery. Combination chemotherapy aids in effective cancer treatment and prevention of drug resistance. Therefore, in this study, we attempted to prepare polyethylene glycosylated (PEGylated) lipid bilayer-wrapped nGO co-loaded with doxorubicin (DOX) and rapamycin (RAPA), GOLDR, for the prevention and treatment of resistant cancers. Our results revealed a stable GOLDR formulation with appropriate particle size (∼170 nm), polydispersity (∼0.19) and drug loading. Free drug combination (DOX and RAPA) presented synergistic anticancer effects in MDA-MB-231, MCF-7, and BT474 cells. Treatment with GOLDR formulation maintained this synergism in treated cancer cells, which was further enhanced by the near infrared (NIR) laser irradiation-induced photothermal effects of nGO. Higher chromatin condensation and apoptotic body formation, and enhanced protein expression of apoptosis-related markers (Bax, p53, p21, and c-caspase 3) following GOLDR treatment in the presence of NIR laser treatment clearly suggests its superiority in effective chemo-photothermal therapy of resistant cancers. The hybrid nanosystem that we developed provides a basis for the effective use of GOLDR treatment in the prevention and treatment of resistant cancer types.

Topics: Doxorubicin; Drug Delivery Systems; Drug Resistance, Neoplasm; Graphite; Humans; Lipid Bilayers; MCF-7 Cells; Neoplasms; Polyethylene Glycols; Sirolimus

Michael N. Hall is this year's recipient of the Lasker Basic Medical Research Award for the identification of the target of rapamycin, TOR. TOR is a master regulator of the cell's growth and metabolic state, and its dysregulation contributes to a variety of diseases, including diabetes, obesity, neurodegenerative disorders, aging, and cancer, making the TOR pathway an attractive therapeutic target.

Topics: Animals; Antifungal Agents; Awards and Prizes; Cells; History, 20th Century; Humans; Neoplasms; Physiology; Signal Transduction; Sirolimus; Switzerland; TOR Serine-Threonine Kinases

Leucyl-tRNA synthetase (LRS) is known to function as leucine sensor in the mammalian target of rapamycin complex 1 (mTORC1) pathway. However, the pathophysiological significance of its activity is not well understood. Here, we demonstrate that the leucine sensor function for mTORC1 activation of LRS can be decoupled from its catalytic activity. We identified compounds that inhibit the leucine-dependent mTORC1 pathway by specifically inhibiting the GTPase activating function of LRS, while not affecting the catalytic activity. For further analysis, we selected one compound, BC-LI-0186, which binds to the RagD interacting site of LRS, thereby inhibiting lysosomal localization of LRS and mTORC1 activity. It also effectively suppressed the activity of cancer-associated MTOR mutants and the growth of rapamycin-resistant cancer cells. These findings suggest new strategies for controlling tumor growth that avoid the resistance to existing mTOR inhibitors resulting from cancer-associated MTOR mutations.Leucyl-tRNA synthetase (LRS) is a leucine sensor of the mTORC1 pathway. Here, the authors identify inhibitors of the GTPase activating function of LRS, not affecting its catalytic activity, and demonstrate that the leucine sensor function of LRS can be a new target for mTORC1 inhibition.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Drug Screening Assays, Antitumor; Female; Humans; Leucine; Leucine-tRNA Ligase; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred BALB C; Mice, Nude; Monomeric GTP-Binding Proteins; Neoplasms; Protein Binding; Signal Transduction; Sirolimus

CD4

Topics: AMP-Activated Protein Kinase Kinases; Antigens, CD; Cell Differentiation; CTLA-4 Antigen; Forkhead Transcription Factors; Gene Expression Regulation; Glucose Transporter Type 1; Humans; Integrin alpha Chains; Interleukin-10; Lectins, C-Type; Mechanistic Target of Rapamycin Complex 1; Metformin; Neoplasms; Protein Kinases; Receptors, Immunologic; Sirolimus; T-Lymphocytes, Regulatory; Trans-Activators; Tumor Microenvironment

The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and metabolism in response to nutrients, energy levels, and growth factors. It contains the atypical kinase mTOR and the RAPTOR subunit that binds to the Tor signalling sequence (TOS) motif of substrates and regulators. mTORC1 is activated by the small GTPase RHEB (Ras homologue enriched in brain) and inhibited by PRAS40. Here we present the 3.0 ångström cryo-electron microscopy structure of mTORC1 and the 3.4 ångström structure of activated RHEB-mTORC1. RHEB binds to mTOR distally from the kinase active site, yet causes a global conformational change that allosterically realigns active-site residues, accelerating catalysis. Cancer-associated hyperactivating mutations map to structural elements that maintain the inactive state, and we provide biochemical evidence that they mimic RHEB relieving auto-inhibition. We also present crystal structures of RAPTOR-TOS motif complexes that define the determinants of TOS recognition, of an mTOR FKBP12-rapamycin-binding (FRB) domain-substrate complex that establishes a second substrate-recruitment mechanism, and of a truncated mTOR-PRAS40 complex that reveals PRAS40 inhibits both substrate-recruitment sites. These findings help explain how mTORC1 selects its substrates, how its kinase activity is controlled, and how it is activated by cancer-associated mutations.

Topics: Adaptor Proteins, Signal Transducing; Amino Acid Motifs; Binding Sites; Biocatalysis; Catalytic Domain; Cryoelectron Microscopy; Crystallography, X-Ray; Enzyme Activation; Humans; Mechanistic Target of Rapamycin Complex 1; Models, Molecular; Mutation; Neoplasms; Protein Binding; Protein Domains; Ras Homolog Enriched in Brain Protein; Regulatory-Associated Protein of mTOR; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; Substrate Specificity; Tacrolimus Binding Protein 1A

New poly(L-lysine)-b-poly(ethylene glycol) copolypeptides have been prepared, where the side-chain amine groups of lysine residues are modified to contain ortho-amine substituted phenylboronic acid, i.e., Wulff-type phenylboronic acid (WBA), groups to improve their pH responsive, carbohydrate binding properties. These block copolymers form nanoscale complexes with glycosylated proteins that are stable at physiological pH, yet dissociate and release the glycoproteins under acidic conditions, similar to those found in endosomal and lysosomal compartments within cells. These results suggest that WBA modified polypeptide copolymers are promising for further development as degradable carriers for intracellular protein delivery.

Topics: A549 Cells; Animals; Antineoplastic Agents; Benzoquinones; Boronic Acids; Cell Proliferation; Cell Survival; Clone Cells; Drug Combinations; Female; Hydrogen-Ion Concentration; Immunohistochemistry; Ki-67 Antigen; Lactams, Macrocyclic; Mice, Nude; Micelles; Necrosis; Neoplasms; Paclitaxel; Peptides; Polyesters; Polyethylene Glycols; Polymers; Proteins; Proto-Oncogene Proteins c-akt; Sirolimus

Epothilones are microtubule inhibitors that are promising alternatives to paclitaxel due to enhanced anticancer efficacy. While epothilones are slightly more water soluble than paclitaxel and more active against paclitaxel-resistant cells, they still require formulation with Cremophor EL and/or cosolvents and drug resistance still limits therapeutic efficacy. In this report, we showed that the combinational treatment of epothilone B (EpoB), 17-N-allylamino-17-demethoxygeldanamycin (17-AAG, Hsp90 inhibitor), and rapamycin (mTOR inhibitor) displays strong anticancer activity in vitro and in vivo. To address the poor water solubility of this 3 drug-combination, they were co-loaded into poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) micelles, and the 3-in-1 loaded PEG-b-PLA micelle (m-EAR) was characterized in terms of drug loading efficiency, particle size, release kinetics. The m-EAR achieved high levels of all three drugs in water; formed micelles with hydrodynamic diameters at ca. 30nm and released the drugs in a sustained manner in vitro at rates slower than individually loaded PEG-b-PLA micelles. In A549-derived xenograft mice, m-EAR (2.0, 15.0, and 7.5mg/kg) caused tumor regression after four weekly injections, whereas EpoB alone (2.0mg/kg) was the same as control. No severe changes in body weight relative to PBS control were observed, attesting to the safety of m-EAR. Collectively, these results suggest that m-EAR provides a simple, but effective and safe EpoB-based combination nanomedicine for cancer therapy.

Topics: A549 Cells; Animals; Antineoplastic Agents; Benzoquinones; Cell Survival; Drug Combinations; Drug Liberation; Epothilones; Female; HSP90 Heat-Shock Proteins; Humans; Lactams, Macrocyclic; Mice, Nude; Micelles; Neoplasms; Polyethylene Glycols; Sirolimus; TOR Serine-Threonine Kinases; Tumor Burden

The risks for transplant outcomes associated with baseline viral serostatus in kidney transplant recipients (KTR) on sirolimus have not been widely studied.. We performed a cohort-study of 61 590 adult KTR in 2000 to 2013. We used Cox regression models to determine the adjusted hazard ratio (aHR) of patient death, death-censored graft loss and posttransplant malignancy associated with the baseline serostatus (+ or -: hepatitis B core [HBc], hepatitis C virus [HCV], Epstein-Barr virus [EBV], or cytomegalovirus [CMV]) in KTR on sirolimus (SRL) + mycophenolate (MPA) or SRL + tacrolimus (Tac), relative to the control-regimen: Tac + MPA.. Compared with Tac + MPA, SRL + MPA, and SRL + Tac were associated with higher risks of 5-year mortality (aHR, 1.41; 95% CI, 1.23-1.60 and aHR, 1.59; 95% CI, 1.38-1.83, respectively) and death-censored graft loss (aHR, 1.41; 95% CI, 1.24-1.60 and aHR, 1.38; 95% CI, 1.21-1.57, respectively). In KTR with negative pretransplant EBV, CMV, HBc, or HCV serostatus, SRL + MPA not SRL + Tac was associated with a lower risk of posttransplant malignancy compared with control (aHR, 0.27; 95% CI, 0.10-0.72; aHR, 0.61; 95% CI, 0.43-0.88; aHR, 0.79; 95% CI, 0.64-0.97; and aHR, 0.80; 95% CI, 0.65-0.98, respectively, for SRL + MPA and aHR, 0.98: 95% CI, 0.52-1.80; aHR, 0.69; 95% CI, 0.46-1.06; aHR, 0.83; 95% CI, 0.66-1.06 and aHR, 0.85; 95% CI, 0.67-1.07, respectively, for SRL + Tac). In KTR with positive serostatus to any of the above viruses, SRL + MPA or SRL + Tac was not associated with a different malignancy risk compared with control.. Compared with Tac + MPA, SRL regimens were associated with higher risks for patient death and graft loss, although SRL + MPA was associated with a lower risk for posttransplant malignancy in kidney allograft recipients with negative pretransplant HBc, HCV, EBV, or CMV serology.

Topics: Adult; Allografts; Antibodies, Viral; Biomarkers; Chi-Square Distribution; Cytomegalovirus Infections; Drug Therapy, Combination; Epstein-Barr Virus Infections; Female; Graft Survival; Hepatitis B; Hepatitis C; Humans; Immunocompromised Host; Immunosuppressive Agents; Kidney Transplantation; Logistic Models; Male; Middle Aged; Multivariate Analysis; Neoplasms; Odds Ratio; Predictive Value of Tests; Proportional Hazards Models; Registries; Retrospective Studies; Risk Factors; Serologic Tests; Sirolimus; Time Factors; Treatment Outcome; United States

Paraptosis is nonapoptotic cell death characterized by massive endoplasmic reticulum (ER)- or mitochondria-derived vacuoles. Induction of paraptosis offers significant advantages for the treatment of chemotherapy-resistant tumors compared with anticancer drugs that rely on apoptosis. Because some natural alkaloids induce paraptotic cell death, a novel series of benzo[a]quinolizidine derivatives were synthesized, and their antiproliferative activity and ability to induce cytoplasmic vacuolation were analyzed. Structural optimization led to the identification of the potent compound 22b, which inhibited cancer cell proliferation in vitro and in vivo and profoundly facilitated paraptosis-like cell death and induced caspase-dependent apoptosis. Further investigation revealed that 22b-mediated vacuolation originated from persistent ER stress and upregulation of LC3B. Paraptosis induced by benzo[a]quinolizidine derivatives thus represents an alternative strategy for cancer chemotherapy.

Topics: Animals; Apoptosis; Cell Proliferation; Dose-Response Relationship, Drug; Drug Design; Drug Screening Assays, Antitumor; Humans; Mice; Molecular Structure; Neoplasms; Quinolizidines; Structure-Activity Relationship; Tumor Cells, Cultured

Solid-organ transplant recipients (OTRs) are at an increased risk for skin cancer. Prior studies have demonstrated a reduced incidence of skin cancer in renal OTRs treated with sirolimus. However, little information exists on the use of sirolimus for the prevention of skin cancer in nonrenal OTRs or those already diagnosed as having a posttransplant cancer.. To compare subsequent skin cancer formation in a mixed-organ cohort of OTRs who were or were not treated with sirolimus after developing a posttransplant index cancer of any type.. A 9-year retrospective cohort study at 2 academic tertiary care centers. Electronic medical records were reviewed for OTRs diagnosed as having a posttransplant cancer of any type to determine the type of organ transplanted, pretransplant and posttransplant cancer, and immunosuppressive medications. Patients underwent transplant from January 1, 2000, to December 31, 2008. Data were collected from July 30, 2011, to December 31, 2012, when follow-up was completed, and analyzed from April 28, 2013, to October 4, 2014.. Factors associated with subsequent skin cancer development were evaluated via multivariate Cox regression analysis.. Of 329 OTRs with an index posttransplant cancer (100 women and 229 men; mean [SD] age, 56 [19] years), 177 (53.8%) underwent renal transplant; 58 (17.6%), heart transplant; 54 (16.4%), lung transplant; 34 (10.3%), liver transplant; and 6 (1.8%), mixed-organ transplant. Ninety-seven OTRs (29.5%) underwent conversion to sirolimus therapy after diagnosis. One hundred thirty OTRs (39.5%) developed second posttransplant cancers, of which 115 cases (88.5%) were skin cancers. An 11.6% reduction in skin cancer risk was observed in the sirolimus-treated vs non-sirolimus-treated groups overall (26 of 97 [26.8%] vs 89 of 232 [38.4%]; P = .045) and among nonrenal OTRs only (8 of 34 [23.5%] vs 44 of 112 [39.3%], respectively), although the latter difference was not significant (P = .09). Independent predictors of skin cancer formation after the index posttransplant cancer were history of pretransplant skin cancer (subhazard ratio, 2.1; 95% CI, 1.2-3.7), skin cancer as the index posttransplant cancer (subhazard ratio, 5.5; 95% CI, 2.5-6.4), and sirolimus treatment (subhazard ratio, 0.6; 95% CI, 0.4-0.9). These same risk factors were associated with skin cancer formation when the analysis was limited to nonrenal OTRs. No difference was found in allograft rejection or death between sirolimus-treated and non-sirolimus-treated groups.. In this mixed-organ cohort of OTRs, patients taking sirolimus after developing posttransplant cancer had a lower risk of developing subsequent skin cancer, with no increased risk for overall mortality. Thus, conversion to sirolimus therapy may be considered in OTRs who develop cancer if the risk for skin cancer is of concern. Larger studies are needed to quantify sirolimus-associated risk reduction for other cancer types.

Topics: Adult; Aged; Cohort Studies; Female; Follow-Up Studies; Humans; Immunosuppressive Agents; Male; Middle Aged; Neoplasms; Organ Transplantation; Proportional Hazards Models; Retrospective Studies; Risk Factors; Sirolimus; Skin Neoplasms; Tertiary Care Centers; Transplant Recipients

Imaging guided techniques have been increasingly employed to investigate the pharmacokinetics (PK) and biodistribution of nanoparticle based drug delivery systems. In most cases, however, the PK profiles of drugs could vary significantly from those of drug delivery carriers upon administration in the blood circulation, which complicates the interpretation of image findings. Herein we applied a genetically encoded luciferase reporter in conjunction with near infrared (NIR) fluorophores to investigate the respective PK profiles of a drug and its carrier in a biodegradable drug delivery system. In this system, a prototype hydrophobic agent, rapamycin (Rapa), was encapsulated into human serum albumin (HSA) to form HSA Rapa nanoparticles, which were then labeled with Cy5 fluorophore to facilitate the fluorescence imaging of HSA carrier. Meanwhile, we employed transgenetic HN12 cells that were modified with a split luciferase reporter, whose bioluminescence function is regulated by Rapa, to reflect the PK profile of the encapsulated agent. It was interesting to discover that there existed an obvious inconsistency of PK behaviors between HSA carrier and rapamycin in vitro and in vivo through near infrared fluorescence imaging (NIFRI) and bioluminescence imaging (BLI) after treatment with Cy5 labeled HSA Rapa. Nevertheless, HSA Rapa nanoparticles manifested favorable in vivo PK and tumor suppression efficacy in a follow-up therapeutic study. The developed strategy of combining a molecular reporter and a fluorophore in this study could be extended to other drug delivery systems to provide profound insights for non-invasive real-time evaluation of PK profiles of drug-loaded nanoparticles in pre-clinical studies.

Topics: Animals; Antineoplastic Agents; Blotting, Western; Carbocyanines; Cell Line, Tumor; Drug Carriers; Fluorescent Dyes; Humans; Luciferases; Mice; Mice, Nude; Microscopy, Confocal; Nanoparticles; Neoplasms; Plasmids; Serum Albumin; Sirolimus; Spectroscopy, Near-Infrared; Tandem Mass Spectrometry; Tissue Distribution

CD11b(+) Gr1(+) myeloid-derived suppressor cells (MDSCs) play critical roles in controlling the processes of tumors, infections, autoimmunity and graft rejection. Immunosuppressive drug rapamycin (RPM), targeting on the key cellular metabolism molecule mTOR, is currently used in clinics to treat patients with allo-grafts, autoimmune diseases and tumors. However, the effect of RPM on MDSCs has not been studied. RPM significantly decreases the cell number and the immunosuppressive ability on T cells of CD11b(+) Ly6C(high) monocytic MDSCs (M-MDSCs) in both allo-grafts-transplanted and tumor-bearing mice respectively. Mice with a myeloid-specific deletion of mTOR have poor M-MDSCs after grafting with allo-skin tissue or a tumor. Grafting of allo-skin or tumors significantly activates glycolysis pathways in myeloid precursor cells in bone marrow, which is inhibited by RPM or mTOR deletion. 2-deoxyglucose (2-DG), an inhibitor of the glycolytic pathway, inhibits M-MDSC differentiation from precursors, while enhancing glycolysis by metformin significantly rescues the RPM-caused deficiency of M-MDSCs. Therefore, we offer evidence supporting that mTOR is an intrinsic factor essential for the differentiation and immunosuppressive function of M-MDSCs and that these metabolism-relevant medicines may impact MDSCs-mediated immunosuppression or immune tolerance induction, which is of considerable clinical importance in treating graft rejection, autoimmune diseases and cancers.

Topics: Allografts; Animals; Cell Count; Cell Differentiation; Disease Models, Animal; Energy Metabolism; Graft Rejection; Immunosuppression Therapy; Mice; Mice, Knockout; Myeloid-Derived Suppressor Cells; Neoplasms; Nitric Oxide Synthase Type II; Signal Transduction; Sirolimus; Skin Transplantation; T-Lymphocyte Subsets; TOR Serine-Threonine Kinases

The ability of Tetra-O-methyl nordihydroguaiaretic acid (M4N) to induce rapid cell death in combination with Etoposide, Rapamycin, or UCN-01 was examined in LNCaP cells, both in cell culture and animal experiments. Mice treated with M4N drug combinations with either Etoposide or Rapamycin showed no evidence of tumor and had a 100% survival rate 100 days after tumor implantation. By comparison all other vehicles or single drug treated mice failed to survive longer than 30 days after implantation. This synergistic improvement of anticancer effect was also confirmed in more than 20 cancer cell lines. In LNCaP cells, M4N was found to reduce cellular ATP content, and suppress NDUFS1 expression while inducing hyperpolarization of mitochondrial membrane potential. M4N-treated cells lacked autophagy with reduced expression of BNIP3 and ATG5. To understand the mechanisms of this anticancer activity of M4N, the effect of this drug on three cancer cell lines (LNCaP, AsPC-1, and L428 cells) was further examined via transcriptome and metabolomics analyses. Metabolomic results showed that there were reductions of 26 metabolites essential for energy generation and/or production of cellular components in common with these three cell lines following 8 hours of M4N treatment. Deep RNA sequencing analysis demonstrated that there were sixteen genes whose expressions were found to be modulated following 6 hours of M4N treatment similarly in these three cell lines. Six out of these 16 genes were functionally related to the 26 metabolites described above. One of these up-regulated genes encodes for CHAC1, a key enzyme affecting the stress pathways through its degradation of glutathione. In fact M4N was found to suppress glutathione content and induce reactive oxygen species production. The data overall indicate that M4N has profound specific negative impacts on a wide range of cancer metabolisms supporting the use of M4N combination for cancer treatments.

Topics: Antineoplastic Agents; Autophagy; Carbohydrate Metabolism; Caspase 7; Cell Line, Tumor; Down-Regulation; Drug Synergism; Energy Metabolism; Etoposide; Glutathione; Humans; Lipid Metabolism; Male; Masoprocol; Metabolic Networks and Pathways; Metabolome; Neoplasms; Oxidative Stress; Reactive Oxygen Species; Sirolimus; Staurosporine

Tuberous sclerosis complex (TSC), caused by loss-of-function mutations in the TSC1 or TSC2 gene, is characterized by benign tumor formation in multiple organs. Hyperactivation of mammalian target of rapamycin complex 1 (mTORC1) is the primary alteration underlying TSC tumors. By analyzing Tsc2-null mouse embryonic fibroblasts (MEFs) and rat uterine leiomyoma-derived Tsc2-null ELT3 cells, we detected evidence for the involvement of cyclooxygenase 2 (COX2) as a downstream target of mTORC1 in the development of TSC tumors. We showed that loss of TSC2 led to decreased COX2 expression through activation of an mTORC1/signal transducer and activator of transcription 3 (STAT3) signaling pathway. Overexpression of COX2 promoted proliferation and tumoral growth of Tsc2-null cells. COX2 knockdown inhibited the proliferation of the control cells. COX2 enhanced Tsc2-null cell growth through upregulation of interleukin-6 (IL-6). In addition, rapamycin in combination with celecoxib, a COX2 inhibitor, strongly inhibited Tsc2-deficient cell growth. We conclude that downregulation of COX2 exerts a protective effect against hyperactivated mTORC1-mediated tumorigenesis caused by the loss of TSC2, and the combination of rapamycin and celecoxib may be an effective new approach to treating TSC.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Carcinogenesis; Celecoxib; Cell Proliferation; Cyclooxygenase 2; Down-Regulation; Mechanistic Target of Rapamycin Complex 1; Mice; Neoplasms; Rats; Sirolimus; Tuberous Sclerosis; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

Evidence is limited regarding the effect of de novo therapy with mammalian target of rapamycin (mTOR) inhibitors on cancer risk after kidney transplantation.. Collaborative Transplant Study data from 78 146 adult recipients of first deceased-donor kidney transplants (1999-2013) were analysed (4279 mTOR inhibitor, 73 867 no mTOR inhibitor) using standard methods. Propensity score matching was performed for analysis of basal cell and squamous cell skin cancer.. Standardized incidence ratios (SIR) versus a matched non-transplant population showed reduced tumour incidence in recipients with de novo mTOR inhibitor therapy compared with no mTOR inhibitor for non-melanoma skin cancer (NMSC) (SIR 5.1 versus 6.1; P =0.019) but not non-NMSC cancers (SIR 1.6 versus 1.7; P =0.35). Within propensity score-matched groups (n = 4265), multivariable Cox regression analysis showed a trend to reduced NMSC with mTOR inhibition [hazard ratio (HR) 0.77; P =0.063] but not for all non-NMSC tumours (HR 0.94; P= 0.59). A significant effect for mTOR inhibition was observed for basal cell carcinoma of the skin (HR 0.56; P= 0.004) but not squamous cell carcinoma (HR 0.87; P= 0.54).. De novo mTOR inhibition was associated with a substantially and significantly reduced risk of basal cell carcinoma of the skin after kidney transplantation. A significant reduction of the incidence of other cancers was not found.

Topics: Adult; Female; Germany; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Incidence; Kidney Transplantation; Middle Aged; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Transplant Recipients

Imaging-guided photothermal therapy (PTT) has promising application for treating tumors. Nevertheless, so far imaging-guided photothermal drug-delivery systems have been developed with limited success for tumor chemo-photothermal therapy. In this study, as the proof-of-concept, a stimuli-responsive tumor-targeting rapamycin/DiR loaded lipid-polyaniline nanoparticle (RDLPNP) for dual-modal imaging-guided enhanced PTT efficacy is reported for the first time. In this system, polyaniline (PANI) with π-π electronic conjugated system and effective photothermal efficiency is chosen as the appropriate model receptor of fluorescence resonance energy transfer (FRET), and loaded cyanine probe (e.g., 1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide, DiR) acts as the donor of near-infrared fluorescence (NIRF). In addition, rapamycin (RAPA), which is used as the antiangiogenesis chemotherapeutic drug, can cutdown the tumor vessels and delay tumor growth obviously. After intravenous treatment of RDLPNPs into Hela tumor bearing mice, fluorescent (from DiR) and enhanced photoacoustic (from DLPNPs) signals were found in tumor site over time, which reached to peak at the 6h time point. After irradiating with an NIR laser, a good anti-tumor effect was observed owing to the enhanced photothermal and antiangiogenic effect of RDLPNPs. These results show that the multifunctional nanoparticle can be used as a promising imaging-guided photothermal drug delivery nanoplatform for cancer therapy.

Topics: Angiogenesis Inhibitors; Aniline Compounds; Animals; Antibiotics, Antineoplastic; Drug Carriers; Drug Delivery Systems; Female; HeLa Cells; Human Umbilical Vein Endothelial Cells; Humans; Hyperthermia, Induced; Mice; Mice, Inbred BALB C; Nanoparticles; Neoplasms; Optical Imaging; Photoacoustic Techniques; Phototherapy; Sirolimus

Emerging evidence from recently published observational studies and an individual patient data meta-analysis shows that mammalian target of rapamycin inhibitor use in kidney transplantation is associated with increased mortality. Therefore, all-cause mortality and allograft loss were compared between use and nonuse of mammalian target of rapamycin inhibitors in patients from Australia and New Zealand, where mammalian target of rapamycin inhibitor use has been greater because of heightened skin cancer risk.. Our longitudinal cohort study included 9353 adult patients who underwent 9558 kidney transplants between January 1, 1996 and December 31, 2012 and had allograft survival ≥1 year. Risk factors for all-cause death and all-cause and death-censored allograft loss were analyzed by multivariable Cox regression using mammalian target of rapamycin inhibitor as a time-varying covariate. Additional analyses evaluated mammalian target of rapamycin inhibitor use at fixed time points of baseline and 1 year.. Patients using mammalian target of rapamycin inhibitors were more likely to be white and have a history of pretransplant cancer. Over a median follow-up of 7 years, 1416 (15%) patients died, and 2268 (24%) allografts were lost. There was a higher risk of all-cause mortality with time-varying mammalian target of rapamycin inhibitor use (hazard ratio, 1.47; 95% confidence interval, 1.23 to 1.76) as well as in the fixed time model analyses comparing mammalian target of rapamycin inhibitor use at baseline (hazard ratio, 1.54; 95% confidence interval, 1.22 to 1.93) and 1 year (hazard ratio, 1.63; 95% confidence interval, 1.32 to 2.01). Time-varying mammalian target of rapamycin inhibitor use was associated with higher risk of death because of malignancy (hazard ratio, 1.37; 95% confidence interval, 1.09 to 1.71). There were no statistically significant differences in the risk of all-cause (hazard ratio, 0.98; 95% confidence interval, 0.85 to 1.12) and death-censored (hazard ratio, 0.85; 95% confidence interval, 0.69 to 1.03) allograft loss between the mammalian target of rapamycin inhibitor use and nonuse groups in the time-varying model as well as the fixed time models.. Mammalian target of rapamycin inhibitor use was associated with a higher risk of all-cause mortality but not allograft loss.

Topics: Adult; Australia; Cause of Death; Everolimus; Female; Graft Rejection; Graft Survival; Humans; Immunosuppressive Agents; Infections; Kidney Failure, Chronic; Kidney Transplantation; Longitudinal Studies; Male; Middle Aged; Neoplasms; New Zealand; Preoperative Period; Proportional Hazards Models; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Transplant Recipients; Treatment Outcome

While combined chemotherapy (CT) with an autophagy inducer and an autophagy inhibitor appears paradoxical, it may provide a more effective perturbation of autophagy pathways. We used two dissimilar cell lines to test the hypothesis that autophagy is the common denominator of cell fate after CT. HA22T cells are characterized by CT-induced apoptosis and use autophagy to prevent cell death, while Huh7.5.1 cells exhibit sustained autophagic morphology after CT. Combined CT and rapamycin treatment resulted in a better combination index (CI) in Huh7.5.1 cells than combined CT and chloroquine, while the reverse was true in HA22T cells. The combination of 3 drugs (triplet drug treatment) had the best CI. After triplet drug treatment, HA22T cells switched from protective autophagy to mitochondrial membrane permeabilization and endoplasmic reticulum stress response-induced apoptosis, while Huh7.5.1 cells intensified autophagic lethality. Most importantly, both cell lines showed activation of Akt after CT, while the triplet combination blocked Akt activation through inhibition of phospholipid lipase D activity. This novel finding warrants further investigation as a broad chemosensitization strategy.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Cell Line, Tumor; Cell Proliferation; Chloroquine; Drug Resistance, Neoplasm; Drug Synergism; Endoplasmic Reticulum Stress; Humans; Male; Mice; Mice, Inbred NOD; Mice, SCID; Mitochondrial Membranes; Neoplasms; Phospholipase D; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Vinca Alkaloids; Xenograft Model Antitumor Assays

The FDA approved drug rapamycin increases lifespan in rodents and delays age-related dysfunction in rodents and humans. Nevertheless, important questions remain regarding the optimal dose, duration, and mechanisms of action in the context of healthy aging. Here we show that 3 months of rapamycin treatment is sufficient to increase life expectancy by up to 60% and improve measures of healthspan in middle-aged mice. This transient treatment is also associated with a remodeling of the microbiome, including dramatically increased prevalence of segmented filamentous bacteria in the small intestine. We also define a dose in female mice that does not extend lifespan, but is associated with a striking shift in cancer prevalence toward aggressive hematopoietic cancers and away from non-hematopoietic malignancies. These data suggest that a short-term rapamycin treatment late in life has persistent effects that can robustly delay aging, influence cancer prevalence, and modulate the microbiome.

Topics: Animals; Anti-Bacterial Agents; Antibiotics, Antineoplastic; Gastrointestinal Microbiome; Longevity; Mice; Neoplasms; Sirolimus

Topics: Animals; Antibiotics, Antineoplastic; Depressive Disorder, Major; Drug Delivery Systems; Humans; Neoplasms; Neurodegenerative Diseases; Sirolimus; TOR Serine-Threonine Kinases

This work spotlights on fabrication of CD44-tropic, layer-by-layer (LbL) coated, liquid crystalline nanoparticles of rapamycin (Rap-LbL-LCNPs) to enhance its water solubility and enable its anticancer use.. Rap-LCNPs were fabricated using hydrotrope method and then coated using LbL self-assembly technique.. LbL coating strategy successfully reduced monoolein-induced hemolysis and increased LCNPs serum stability. Lyophilized Rap-LbL-LCNPs were successfully sterilized using γ-radiations. In CD44-overexpressed MDA-MB-231 cells, Rap-LbL-LCNPs demonstrated superior cytotoxicity compared with the nontargeted formulation. Rap-LbL-LCNPs showed 3.35-fold increase in bioavailability compared with free drug. Rap-LbL-LCNPs significantly inhibited tumor growth, enhanced animal survival and reduced nephrotoxic and hyperglycemic effects of Rap.. LbL coating strategy of Rap-LCNPs could serve as a promising approach that facilitates Rap use in cancer therapy.

Topics: Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Hyaluronan Receptors; Liquid Crystals; Nanoparticles; Neoplasms; Sirolimus; Solubility; Tropism; Water

A series of quinoline derivatives featuring the novelty of introducing intra-molecular hydrogen bonding scaffold (iMHBS) were designed, synthesized and biologically evaluated for their mTOR inhibitory activity, as well as anti-proliferative efficacies against HCT-116, PC-3 and MCF-7 cell lines. As a result, six compounds exhibited significant inhibition against mTOR with IC50 values below 35nM. Compound 15a, the most potent mTOR inhibitor reported herein (IC50=14nM), also displayed the most favorable cellular activities, with the IC50 values of 0.46, 0.61 and 0.24μM against HCT-116, PC-3 and MCF-7, respectively. Besides, several compounds in this series were identified to be selective over class I PI3Ks. Further western blot analysis of 16b, a representative compound in this series, highlighted their advantage in surmounting the S6K/IRS1/PI3K negative feedback loop upon dual inhibition of mTORC1 and mTORC2. In addition to the remarkable activity, 15a demonstrated acceptable stability in simulated gastric fluid (SGF), simulated intestinal fluid (SIF) and liver microsome, thereby being valuable for extensive in vivo investigation.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Drug Design; HCT116 Cells; Humans; Hydrogen Bonding; MCF-7 Cells; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Molecular Docking Simulation; Multiprotein Complexes; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Kinase Inhibitors; Quinolines; Signal Transduction; TOR Serine-Threonine Kinases

Topics: Antineoplastic Combined Chemotherapy Protocols; Female; Humans; Male; Neoplasms; Protein Kinase Inhibitors; Pyridones; Pyrimidinones; Sirolimus

Sirolimus has anti-carcinogenic properties and can be included in maintenance immunosuppressive therapy following kidney transplantation. We investigated sirolimus effects on cancer incidence among kidney recipients. The US transplant registry was linked with 15 population-based cancer registries and national pharmacy claims. Recipients contributed sirolimus-exposed time when sirolimus claims were filled, and unexposed time when other immunosuppressant claims were filled without sirolimus. Cox regression was used to estimate associations with overall and specific cancer incidence, excluding nonmelanoma skin cancers (not captured in cancer registries). We included 32,604 kidney transplants (5687 sirolimus-exposed). Overall, cancer incidence was suggestively lower during sirolimus use (hazard ratio [HR] = 0.88, 95% confidence interval [CI] = 0.70-1.11). Prostate cancer incidence was higher during sirolimus use (HR = 1.86, 95% CI = 1.15-3.02). Incidence of other cancers was similar or lower with sirolimus use, with a 26% decrease overall (HR = 0.74, 95% CI = 0.57-0.96, excluding prostate cancer). Results were similar after adjustment for demographic and clinical characteristics. This modest association does not provide strong evidence that sirolimus prevents posttransplant cancer, but it may be advantageous among kidney recipients with high cancer risk. Increased prostate cancer diagnoses may result from sirolimus effects on screen detection.

Topics: Adult; Female; Follow-Up Studies; Glomerular Filtration Rate; Graft Rejection; Humans; Immunosuppressive Agents; Incidence; Kidney Failure, Chronic; Kidney Function Tests; Kidney Transplantation; Male; Middle Aged; Neoplasms; Prognosis; Registries; Risk Assessment; Sirolimus; United States

Accumulating evidence indicates that mammalian target of rapamycin (mTOR) exerts a crucial role in aerobic glycolysis and tumorigenesis, but the underlying mechanisms remain largely obscure. Results from Tsc1- or Tsc2-null mouse embryonic fibroblasts (MEFs) and human cancer cell lines consistently indicate that the expression of glucose transporter 3 (Glut3) is dramatically up-regulated by mTOR. The rapamycin-sensitive mTOR complex 1 (mTORC1), but not the rapamycin-insensitive mTOR complex 2 (mTORC2), was involved in the regulation of Glut3 expression. Moreover, mTORC1 enhances Glut3 expression through the activation of the IKK/NFκB pathway. Depletion of Glut3 led to the suppression of aerobic glycolysis, the inhibition of cell proliferation and colony formation, and the attenuation of the tumorigenic potential of the cells with aberrantly hyper-activated mTORC1 signaling in nude mice. We conclude that Glut3 is a downstream target of mTORC1, and it is critical for oncogenic mTORC1-mediated aerobic glycolysis and tumorigenesis. Hence Glut3 may be a potential target for therapy against cancers caused by the aberrantly activated mTORC1 signaling.

Topics: Animals; Binding Sites; Cell Line, Tumor; Cell Proliferation; Glucose Transporter Type 3; Glycolysis; HEK293 Cells; Humans; Male; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice; Mice, Inbred BALB C; Mice, Nude; Multiprotein Complexes; Neoplasms; NF-kappa B; Promoter Regions, Genetic; Rats; RNA Interference; Signal Transduction; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Transfection; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Burden; Tumor Suppressor Proteins; Up-Regulation

Full-dose sirolimus (SRL) therapy without a calcineurin inhibitor (CNI) reduces the incidence of malignancy after renal transplantation, but with significant side effects. We hypothesized that de novo therapy with low-dose SRL combined with a CNI could still prevent cancer in renal transplant recipients.. A retrospective case-control study was performed to assess the cancer incidence among renal transplant patients who had undergone surgery in our transplant centers between January 2000 and June 2012. Patients who received low-dose SRL and a CNI (SRL group, n = 189) were compared with patients receiving conventional CNI-based therapy in the same hospitals (Conventional group, n = 271).. The 5-year graft and patient survival rates were comparable between the two groups. Seven patients in the SRL group and 24 patients in the Conventional group developed malignancies during mean follow-up periods of 68.2 ± 37.5 months and 81.7 ± 51.4 months, respectively. The cancer incidence at 5 years was significantly lower in the SRL group (1.9%), than that in the Conventional group (6.7%; p = 0.04). By multivariate analyses, SRL therapy (p = 0.04), male sex (p = 0.04), and younger age (p = 0.01) were significantly associated with a lower risk of malignancy after kidney transplantation.. De novo therapy with low-dose SRL combined with a CNI was associated with reduced risk of post-transplant cancer in renal transplant recipients. De novo cancer prevention using a low-dose proliferation signal inhibitor such as SRL could be effective for renal transplant recipients.

Topics: Adult; Calcineurin Inhibitors; Case-Control Studies; Cyclosporine; Drug Therapy, Combination; Female; Glomerular Filtration Rate; Humans; Immunosuppressive Agents; Kaplan-Meier Estimate; Kidney Transplantation; Male; Middle Aged; Multivariate Analysis; Neoplasms; Postoperative Complications; Proportional Hazards Models; Retrospective Studies; Risk Factors; Sirolimus; Survival Rate; Tacrolimus; Taiwan; Treatment Outcome

Autophagy is an important oncotarget that can be modulated during anti-cancer therapy. Enhancing autophagy using chemotherapy and rapamycin (Rapa) treatment and then inhibiting it using hydroxychloroquine (HCQ) could synergistically improve therapy outcome in cancer patients. It is still unclear whether addition of Rapa and HCQ to chemotherapy could be used for reversing drug resistance.. Twenty-five stage IV cancer patients were identified. They had no clinical response to first-line metronomic chemotherapy; the patients were salvaged by adding an autophagy inducer (Rapa, 2 mg/day) and an autophagosome inhibitor (HCQ, 400 mg/day) to their current metronomic chemotherapy for at least 3 months. Patients included 4 prostate, 4 bladder, 4 lung, 4 breast, 2 colon, and 3 head and neck cancer patients as well as 4 sarcoma patients.. Chemotherapy was administered for a total of 137 months. The median duration of chemotherapy cycles per patient was 4 months (95% confidence interval, 3-7 months). The overall response rate to this treatment was of 40%, with an 84% disease control rate. The most frequent and clinically significant toxicities were myelotoxicities. Grade ≥3 leucopenia occurred in 6 patients (24%), grade ≥3 thrombocytopenia in 8 (32%), and anemia in 3 (12%). None of them developed febrile neutropenia. Non-hematologic toxicities were fatigue (total 32%, with 1 patient developing grade 3 fatigue), diarrhea (total 20%, 1 patient developed grade 3 fatigue), reversible grade 3 cardiotoxicity (1 patient), and grade V liver toxicity from hepatitis B reactivation (1 patient).. Our results of Rapa, HCQ and chemotherapy triplet combination suggest autophagy is a promising oncotarget and warrants further investigation in phase II studies.

Topics: Administration, Metronomic; Aged; Antineoplastic Combined Chemotherapy Protocols; Autophagy; Dose-Response Relationship, Drug; Female; Humans; Hydroxychloroquine; Male; Middle Aged; Neoplasm Metastasis; Neoplasms; Pilot Projects; Salvage Therapy; Sirolimus; Treatment Outcome

We hypothesized that lymphoid-selective host conditioning and subsequent adoptive transfer of sirolimus-resistant allogeneic T cells (T-Rapa), when combined with high-dose sirolimus drug therapy in vivo, would safely achieve antitumor effects while avoiding GVHD.. Patients (n = 10) with metastatic renal cell carcinoma (RCC) were accrued because this disease is relatively refractory to high-dose conditioning yet may respond to high-dose sirolimus. A 21-day outpatient regimen of weekly pentostatin (P; 4 mg/m(2)/dose) combined with daily, dose-adjusted cyclophosphamide (C; ≤200 mg/d) was designed to deplete and suppress host T cells. After PC conditioning, patients received matched sibling, T-cell-replete peripheral blood stem cell allografts, and high-dose sirolimus (serum trough target, 20-30 ng/mL). To augment graft-versus-tumor (GVT) effects, multiple T-Rapa donor lymphocyte infusions (DLI) were administered (days 0, 14, and 45 posttransplant), and sirolimus was discontinued early (day 60 posttransplant).. PC conditioning depleted host T cells without neutropenia or infection and facilitated donor engraftment (10 of 10 cases). High-dose sirolimus therapy inhibited multiple T-Rapa DLI, as evidenced by stable mixed donor/host chimerism. No antitumor responses were detected by RECIST criteria and no significant classical acute GVHD was observed.. Immune-selective PC conditioning represents a new approach to safely achieve alloengraftment without neutropenia. However, allogeneic T cells generated ex vivo in sirolimus are not resistant to the tolerance-inducing effects of in vivo sirolimus drug therapy, thereby cautioning against use of this intervention in patients with refractory cancer.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Carcinoma, Renal Cell; Cyclophosphamide; Female; Graft vs Tumor Effect; Humans; Immunophenotyping; Immunotherapy, Adoptive; Lymphocyte Depletion; Male; Middle Aged; Neoplasm Metastasis; Neoplasms; Pentostatin; Peripheral Blood Stem Cell Transplantation; Phenotype; Sirolimus; T-Lymphocyte Subsets; Transplantation Chimera; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome

With this study we aimed to research the effects of immunosuppressive drugs, their cumulative doses, and viral infections on development of malign tumors in patients who have undergone treatment for 5 years.. We examined 100 patients who underwent renal transplantation from 2004 to 2009. Patients had mycophenolate mofetil and steroid in addition to cyclosporine, sirolimus, or tacrolimus as immunosuppressive treatment. For malignancy screening, physical examination, radiologic and endoscopic screening were done, and immunosuppressive drugs and their cumulative doses, age, sex, body mass index (BMI), dialysis history, and viral infection history were investigated.. The mean age of patients was 42.03 ± 11.30 years. There were 1 colon cancer patient, 1 retroperitoneal liposarcoma, 1 renal oncocytoma, 3 Kaposi sarcoma patients treated with cyclosporine; in those treated with Tac there were 1 basal cell carcinoma, 1 Kaposi sarcoma, 2 thyroid carcinoma, 1 breast carcinoma, 1 bladder carcinoma, 1 renal cell carcinoma, and 1 colon carcinoma patients. The mean age of patients having carcinoma was statistically significant compared with those without cancer (P < .01). The prednisolone cumulative dose was significantly higher in carcinoma patients than in patients without carcinoma (P < .01).. The use of long-term chronic immunosuppressive therapy may increase the development of cancer. The risk of carcinoma increases with increasing drug dose and time period of the immunosuppressive drug. There was not a negative effect on cancer prevalence in patients with cyclosporine or tacrolimus. But the cumulative dose of steroids significantly increased malignancy occurence.

Topics: Adult; Breast Neoplasms; Carcinoma; Colonic Neoplasms; Cyclosporine; Early Detection of Cancer; Female; Humans; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Mycophenolic Acid; Neoplasms; Retroperitoneal Neoplasms; Sarcoma, Kaposi; Sirolimus; Steroids; Tacrolimus; Thyroid Neoplasms; Time Factors; Urologic Neoplasms

The metabolic sensor mTOR broadly regulates cell growth and division in cancer cells, leading to a significant focus on studies of rapamycin and its analogues as candidate anticancer drugs. However, mTOR inhibitors have failed to produce useful clinical efficacy, potentially because mTOR is also critical in T cells implicated in immunosurveillance. Indeed, recent studies using rapamycin have demonstrated the important role of mTOR in differentiation and induction of the CD8+ memory in T-cell responses associated with antitumor properties. In this study, we demonstrate that rapamycin harms antitumor immune responses mediated by T cells in the setting of cancer vaccine therapy. Specifically, we analyzed how rapamycin affects the antitumor efficacy of a human papilloma virus E7 peptide vaccine (CyaA-E7) capable of eradicating tumors in the TC-1 mouse model of cervical cancer. In animals vaccinated with CyaA-E7, rapamycin administration completely abolished recruitment of CD8+ T cells into TC-1 tumors along with the ability of the vaccine to reduce infiltration of T regulatory cells and myeloid-derived suppressor cells. Moreover, rapamycin completely abolished vaccine-induced cytotoxic T-cell responses and therapeutic activity. Taken together, our results demonstrate the powerful effects of mTOR inhibition in abolishing T-cell-mediated antitumor immune responses essential for the therapeutic efficacy of cancer vaccines.

Topics: Animals; Antibiotics, Antineoplastic; Cancer Vaccines; CD8-Positive T-Lymphocytes; Cell Line, Tumor; Disease Models, Animal; Female; Flow Cytometry; Humans; Mice, Inbred C57BL; Myeloid Cells; Neoplasms; Papillomavirus E7 Proteins; Sirolimus; T-Lymphocytes, Cytotoxic; T-Lymphocytes, Regulatory; TOR Serine-Threonine Kinases; Tumor Burden

Topics: Clinical Trials as Topic; Humans; Models, Biological; Mutation; Neoplasms; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Effective choice of anticancer drugs is important problem of modern medicine. We developed a method termed OncoFinder for the analysis of new type of biomarkers reflecting activation of intracellular signaling and metabolic molecular pathways. These biomarkers may be linked with the sensitivity to anticancer drugs. In this study, we compared the experimental data obtained in our laboratory and in the Genomics of Drug Sensitivity in Cancer (GDS) project for testing response to anticancer drugs and transcriptomes of various human cell lines. The microarray-based profiling of transcriptomes was performed for the cell lines before the addition of drugs to the medium, and experimental growth inhibition curves were built for each drug, featuring characteristic IC50 values. We assayed here four target drugs - Pazopanib, Sorafenib, Sunitinib and Temsirolimus, and 238 different cell lines, of which 11 were profiled in our laboratory and 227 - in GDS project. Using the OncoFinder-processed transcriptomic data on ~600 molecular pathways, we identified pathways showing significant correlation between pathway activation strength (PAS) and IC50 values for these drugs. Correlations reflect relationships between response to drug and pathway activation features. We intersected the results and found molecular pathways significantly correlated in both our assay and GDS project. For most of these pathways, we generated molecular models of their interaction with known molecular target(s) of the respective drugs. For the first time, our study uncovered mechanisms underlying cancer cell response to drugs at the high-throughput molecular interactomic level.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Computational Biology; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genomics; HeLa Cells; Hep G2 Cells; Humans; Indazoles; Indoles; Inhibitory Concentration 50; Jurkat Cells; MCF-7 Cells; Neoplasms; Niacinamide; Oligonucleotide Array Sequence Analysis; Phenylurea Compounds; Pyrimidines; Pyrroles; Sirolimus; Sorafenib; Sulfonamides; Sunitinib; Transcriptome

mTOR - the mammalian/mechanistic target of rapamycin - has been implicated as a key signaling node for promoting survival of cancer cells. However, clinical trials that have targeted mTOR with rapamycin or rapamycin analogs have had minimal impact. In spite of the high specificity of rapamycin for mTOR, the doses needed to suppress key mTOR substrates have proved toxic. We report here that rapamycin when combined with AICAR - a compound that activates AMP-activated protein kinase makes rapamycin cytotoxic rather than cytostatic at doses that are tolerated clinically. AICAR by itself is able to suppress mTOR complex 1 (mTORC1), but also stimulates a feedback activation of mTORC2, which activates the survival kinase Akt. However, AICAR also suppresses production of phosphatidic acid (PA), which interacts with mTOR in a manner that is competitive with rapamycin. The reduced level of PA sensitizes mTORC2 to rapamycin at tolerable nano-molar doses leading reduced Akt phosphorylation and apoptosis. This study reveals how the use of AICAR enhances the efficacy of rapamycin such that rapamycin at low nano-molar doses can suppress mTORC2 and induce apoptosis in human cancer cells at doses that are clinically tolerable.

Topics: Aminoimidazole Carboxamide; Antibiotics, Antineoplastic; Cell Cycle Checkpoints; Cell Proliferation; Dose-Response Relationship, Drug; Drug Therapy, Combination; Humans; MCF-7 Cells; Neoplasms; Ribonucleotides; Sirolimus; Treatment Outcome

Suppression of tumor metastasis is a key strategy for successful cancer interventions. Previous studies indicated that rapamycin (sirolimus) may promote tumor regression activity or enhance immune response against tumor targets. However, rapamycin also exhibits immunosuppressant effects and is hence used clinically as an organ transplantation drug. We hypothesized that the immunosuppressive activities of rapamycin might also negatively mediate host immunity, resulting in promotion of tumor metastasis. In this study, the effects of rapamycin and phytochemical shikonin were investigated in vitro and in vivo in a 4T1 mouse mammary tumor model through quantitative assessment of immunogenic cell death (ICD), autophagy, tumor growth and metastasis. Tumor-bearing mice were immunized with test vaccines to monitor their effect on tumor metastasis. We found that intraperitoneal (ip) administration of rapamycin after a tumor-resection surgery drastically increased the metastatic activity of 4T1 tumors. Possible correlation of this finding to human cancers was suggested by epidemiological analysis of data from Taiwan's National Health Insurance Research Database (NHIRD). Since our previous studies showed that modified tumor cell lysate (TCL)-pulsed, dendritic cell (DC)-based cancer vaccines can effectively suppress metastasis in mouse tumor models, we assessed whether such vaccines may help offset this rapamycin-promoted metastasis. We observed that shikonin efficiently induced ICD of 4T1 cells in culture, and DC vaccines pulsed with shikonin-treated TCL (SK-TCL-DC) significantly suppressed rapamycin-enhanced metastasis and Treg cell expansion in test mice. In conclusion, rapamycin treatment in mice (and perhaps in humans) promotes metastasis and the effect may be offset by treatment with a DC-based cancer vaccine.

Topics: Adult; Animals; Autophagy; Cancer Vaccines; Cell Differentiation; Cell Line, Tumor; Dendritic Cells; Female; Humans; Male; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Middle Aged; Naphthoquinones; Neoplasm Metastasis; Neoplasms; Sirolimus; T-Lymphocytes, Regulatory; Th1 Cells; Th17 Cells; Young Adult

Rapamycin has demonstrated potent anti-tumor activity in preclinical and clinical studies. However, the clinical development of its formulations was hampered due to its poor solubility and undesirable distribution in vivo. Chemical modification of rapamycin presents an opportunity for overcoming the obstacles and improving its therapeutic index. The objective of this study is to develop a drug-polymer conjugate to increase the solubility and cellular uptake of rapamycin.. We developed the rapamycin-polymer conjugate using a novel, linear, poly(ethylene glycol) (PEG) based multiblock copolymer. Cytotoxicity and cellular uptake of the rapamycin-polymer conjugate were evaluated in various cancer cells.. The rapamycin-polymer conjugate provides enhanced solubility in water compared with free rapamycin and shows profound activity against a panel of human cancer cell lines. The rapamycin-polymer conjugate also presents high drug loading capacity (wt% ~ 26%) when GlyGlyGly is used as a linker. Cellular uptake of the conjugate was confirmed by confocal microscopic examination of PC-3 cells that were cultured in the presence of FITC-labled polymer (FITC-polymer).. This study suggests that the rapamycin-polymer conjugate is a novel anti-cancer agent that may provide an attractive strategy for treatment of a wide variety of tumors.

Topics: Antibiotics, Antineoplastic; Cell Line, Tumor; Drug Carriers; Humans; Neoplasms; Polyethylene Glycols; Polymers; Sirolimus; Solubility

Hypoxia-inducible factor 1 (HIF-1) plays a key role in the cellular adaptation to hypoxia. Although HIF-1 is usually strongly suppressed by posttranslational mechanisms during normoxia, HIF-1 is active and enhances tumorigenicity in malignant tumor cells that express the membrane protease MT1-MMP. The cytoplasmic tail of MT1-MMP, which can bind a HIF-1 suppressor protein called factor inhibiting HIF-1 (FIH-1), promotes inhibition of FIH-1 by Mint3 during normoxia. To explore possible links between HIF-1 activation by MT1-MMP/Mint3 and tumor growth signals, we surveyed a panel of 252 signaling inhibitors. The mTOR inhibitor rapamycin was identified as a possible modulator, and it inhibited the mTOR-dependent phosphorylation of Mint3 that is required for FIH-1 inhibition. A mutant Mint3 protein that cannot be phosphorylated exhibited a reduced ability to inhibit FIH-1 and promoted tumor formation in mice. These data suggest a novel molecular link between the important hub proteins MT1-MMP and mTOR that contributes to tumor malignancy.

Topics: Adaptor Proteins, Signal Transducing; Animals; Antibiotics, Antineoplastic; Carbazoles; Carrier Proteins; Cell Line, Tumor; Female; HEK293 Cells; Humans; Hypoxia-Inducible Factor 1; Immunoblotting; Matrix Metalloproteinase 14; Mice; Mice, Inbred BALB C; Mice, Nude; Mixed Function Oxygenases; Mutation; Neoplasms; Phosphorylation; Protein Binding; Protein Kinase Inhibitors; Repressor Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Sirolimus; TOR Serine-Threonine Kinases; Transplantation, Heterologous

Although inhibition of the insulin-like growth factor (IGF) signaling pathway was expected to eliminate a key resistance mechanism for EGF receptor (EGFR)-driven cancers, the effectiveness of IGF-I receptor (IGF-IR) inhibitors in clinical trials has been limited. A multiplicity of survival mechanisms are available to cancer cells. Both IGF-IR and the ErbB3 receptor activate the PI3K/AKT/mTOR axis, but ErbB3 has only recently been pursued as a therapeutic target. We show that coactivation of the ErbB3 pathway is prevalent in a majority of cell lines responsive to IGF ligands and antagonizes IGF-IR-mediated growth inhibition. Blockade of the redundant IGF-IR and ErbB3 survival pathways and downstream resistance mechanisms was achieved with MM-141, a tetravalent bispecific antibody antagonist of IGF-IR and ErbB3. MM-141 potency was superior to monospecific and combination antibody therapies and was insensitive to variation in the ratio of IGF-IR and ErbB3 receptors. MM-141 enhanced the biologic impact of receptor inhibition in vivo as a monotherapy and in combination with the mTOR inhibitor everolimus, gemcitabine, or docetaxel, through blockade of IGF-IR and ErbB3 signaling and prevention of PI3K/AKT/mTOR network adaptation.

Topics: Animals; Antibodies, Bispecific; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Deoxycytidine; Docetaxel; Everolimus; Female; Gemcitabine; Humans; Mice, Inbred NOD; Mice, Nude; Mice, SCID; Neoplasms; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Receptor, ErbB-3; Receptor, IGF Type 1; Signal Transduction; Sirolimus; Taxoids; TOR Serine-Threonine Kinases; Tumor Burden; Xenograft Model Antitumor Assays

Insulin-like growth factor (IGF) signaling is thought to play a role in the development and progression of multiple cancer types. To date, therapeutic strategies aimed at disrupting IGF signaling have largely focused on antibodies that target the IGF-I receptor (IGF-IR). Here, we describe the pharmacologic profile of BI 836845, a fully human monoclonal antibody that utilizes an alternative approach to IGF signaling inhibition by selectively neutralizing the bioactivity of IGF ligands. Biochemical analyses of BI 836845 demonstrated high affinity to human IGF-I and IGF-II, resulting in effective inhibition of IGF-induced activation of both IGF-IR and IR-A in vitro. Cross-reactivity to rodent IGFs has enabled rigorous assessment of the pharmacologic activity of BI 836845 in preclinical models. Pharmacodynamic studies in rats showed potent reduction of serum IGF bioactivity in the absence of metabolic adverse effects, leading to growth inhibition as evidenced by reduced body weight gain and tail length. Moreover, BI 836845 reduced the proliferation of human cell lines derived from different cancer types and enhanced the antitumor efficacy of rapamycin by blocking a rapamycin-induced increase in upstream signaling in vitro as well as in human tumor xenograft models in nude mice. Our data suggest that BI 836845 represents a potentially more effective and tolerable approach to the inhibition of IGF signaling compared with agents that target the IGF-I receptor directly, with potential for rational combinations with other targeted agents in clinical studies.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antibodies, Neutralizing; Antineoplastic Combined Chemotherapy Protocols; Blotting, Western; Cell Line; Cell Line, Tumor; Cell Proliferation; Female; Humans; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Male; Mice, Inbred Strains; Mice, Nude; Neoplasms; Phosphorylation; Proto-Oncogene Proteins c-akt; Receptor, IGF Type 1; Signal Transduction; Sirolimus; Treatment Outcome; Xenograft Model Antitumor Assays

Genes encoding components of the PI3K-AKT-mTOR signaling axis are frequently mutated in cancer, but few mutations have been characterized in MTOR, the gene encoding the mTOR kinase. Using publicly available tumor genome sequencing data, we generated a comprehensive catalog of mTOR pathway mutations in cancer, identifying 33 MTOR mutations that confer pathway hyperactivation. The mutations cluster in six distinct regions in the C-terminal half of mTOR and occur in multiple cancer types, with one cluster particularly prominent in kidney cancer. The activating mutations do not affect mTOR complex assembly, but a subset reduces binding to the mTOR inhibitor DEPTOR. mTOR complex 1 (mTORC1) signaling in cells expressing various activating mutations remains sensitive to pharmacologic mTOR inhibition, but is partially resistant to nutrient deprivation. Finally, cancer cell lines with hyperactivating MTOR mutations display heightened sensitivity to rapamycin both in culture and in vivo xenografts, suggesting that such mutations confer mTOR pathway dependency.

Topics: Animals; Antibiotics, Antineoplastic; Cell Line, Tumor; Databases, Factual; HEK293 Cells; HeLa Cells; Humans; MAP Kinase Signaling System; MCF-7 Cells; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice; Mice, Nude; Multiprotein Complexes; Mutation; Neoplasms; Neoplasms, Experimental; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

The tumor microenvironment plays an important role in the tumor's progression and metastasis. Therefore, successful alteration of this delicate setting against the tumor's favor can open a window for therapeutic efficacy. We have developed a modality to bring about treatment-induced alterations in the tumor microenvironment by employing the synergistic effects between two drugs. Co-delivery of rapamycin (RAPA), an mTOR inhibitor that may offer notable therapy through antiangiogenic activity, alongside cisplatin can foster significant potency as RAPA sensitizes A375 melanoma cells to cisplatin therapy through microenvironment modulation. However, encapsulation of these drugs into poly(lactic-co-glycolic acid) (PLGA) NPs was inefficient due to the incompatibility between the two free drugs and the polymer matrix. Here, we show cisplatin can be made hydrophobic by coating a nanoprecipitate (cores) of the drug with dioleoylphosphatidic acid (DOPA). These DOPA coated cisplatin cores are compatible with PLGA and can be coencapsulated in PLGA NPs alongside RAPA at a molar ratio to promote synergistic antitumor activity. The presence of the cisplatin cores significantly improved the encapsulation of RAPA into PLGA NPs. Furthermore, PLGA NPs containing both cisplatin cores and RAPA induced significant apoptosis on A375-luc human melanoma cells in vitro. Additionally, they inhibited the growth of A375-luc melanoma in a xenograft tumor model through modulation of the tumor vasculature and permitted enhanced penetration of NPs into the tumor.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Chromatography, High Pressure Liquid; Cisplatin; Dihydroxyphenylalanine; Disease Progression; Drug Carriers; Humans; In Situ Nick-End Labeling; Lactic Acid; Melanoma; Mice; Nanoparticles; Nanotechnology; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms; Platelet Endothelial Cell Adhesion Molecule-1; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Sirolimus; Skin Neoplasms; Solvents; Tumor Microenvironment

Ribonucleotide reductase (RNR) plays a critical role in catalyzing the biosynthesis and maintaining the intracellular concentration of 4 deoxyribonucleoside triphosphates (dNTPs). Unbalanced or deficient dNTP pools cause serious genotoxic consequences. Autophagy is the process by which cytoplasmic constituents are degraded in lysosomes to maintain cellular homeostasis and bioenergetics. However, the role of autophagy in regulating dNTP pools is not well understood. Herein, we reported that starvation- or rapamycin-induced autophagy was accompanied by a decrease in RNR activity and dNTP pools in human cancer cells. Furthermore, downregulation of the small subunit of RNR (RRM2) by siRNA or treatment with the RNR inhibitor hydroxyurea substantially induced autophagy. Conversely, cancer cells with abundant endogenous intracellular dNTPs or treated with dNTP precursors were less responsive to autophagy induction by rapamycin, suggesting that autophagy and dNTP pool levels are regulated through a negative feedback loop. Lastly, treatment with si-RRM2 caused an increase in MAP1LC3B, ATG5, BECN1, and ATG12 transcript abundance in xenografted Tu212 tumors in vivo. Together, our results revealed a previously unrecognized reciprocal regulation between dNTP pools and autophagy in cancer cells.

Topics: Animals; Autophagy; Gene Knockdown Techniques; Humans; Hydroxyurea; Intracellular Space; Mice, Inbred NOD; Mice, SCID; Neoplasms; Nucleotides; Ribonucleoside Diphosphate Reductase; RNA, Small Interfering; Signal Transduction; Sirolimus; Xenograft Model Antitumor Assays

Mammalian target rapamycin inhibitors (m-TORi) are increasingly used in patients undergoing liver transplantation (LT). Yet, there is rising concern that they also could impair wound healing and favor the development of several surgical complications. This report was designed to evaluate both feasibility and safety of major surgery in liver transplant recipients receiving m-TORi-based immunosuppression without therapeutic discontinuation.. From 2007 to 2012, six liver transplant recipients underwent nine major abdominal or thoracic surgical procedures without m-TORi discontinuation or specific dosage adjustment. Their characteristics and postoperative outcomes were retrospectively analyzed.. Indications for m-TORi were de novo or recurrent malignant disease in five patients and calcineurin inhibitors related neurologic toxicity in one patient. Abdominal procedures, thoracic procedures, and combined thoracic and abdominal procedures were performed in six, two, and one cases respectively. Emergency surgery was performed in one case and elective procedures were performed in eight cases, including five for malignant disease and three for late surgical complications following LT. No patient died postoperatively. One major complication was observed, but no patient required reoperation. No evisceration, incisional surgical site infection, or lymphocele occurred.. Major surgery in liver transplant recipients receiving m-TOR inhibitors appears both feasible and safe without therapeutic discontinuation or specific dosage adjustment.

Topics: Anastomosis, Surgical; Everolimus; Female; Hepatectomy; Hepatic Duct, Common; Herniorrhaphy; Humans; Immunosuppressive Agents; Jejunum; Liver Transplantation; Male; Middle Aged; Neoplasms; Pancreaticoduodenectomy; Pneumonectomy; Reoperation; Retrospective Studies; Sirolimus; Thoracotomy; TOR Serine-Threonine Kinases; Transplant Recipients

We tested the antitumor efficacy of mTOR catalytic site inhibitor MLN0128 in models with intrinsic or acquired rapamycin-resistance. Cell lines that were intrinsically rapamycin-resistant as well as those that were intrinsically rapamycin-sensitive were sensitive to MLN0128 in vitro. MLN0128 inhibited both mTORC1 and mTORC2 signaling, with more robust inhibition of downstream 4E-BP1 phosphorylation and cap-dependent translation compared to rapamycin in vitro. Rapamycin-sensitive BT474 cell line acquired rapamycin resistance (BT474 RR) with prolonged rapamycin treatment in vitro. This cell line acquired an mTOR mutation (S2035F) in the FKBP12-rapamycin binding domain; mTORC1 signaling was not inhibited by rapalogs but was inhibited by MLN0128. In BT474 RR cells, MLN0128 had significantly higher growth inhibition compared to rapamycin in vitro and in vivo. Our results demonstrate that MLN0128 may be effective in tumors with intrinsic as well as acquired rapalog resistance. mTOR mutations are a mechanism of acquired resistance in vitro; the clinical relevance of this observation needs to be further evaluated.

Topics: Allosteric Regulation; Animals; Antineoplastic Agents; Benzoxazoles; Catalytic Domain; Cell Line, Tumor; Cell Proliferation; Drug Design; Drug Resistance, Neoplasm; Female; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice, Nude; Molecular Targeted Therapy; Multiprotein Complexes; Mutation; Neoplasms; Protein Kinase Inhibitors; Pyrimidines; Signal Transduction; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Tumor Burden; Xenograft Model Antitumor Assays

Mechanistic target of rapamycin (mTOR) is a central component of the essential signaling pathway that regulates cell growth and proliferation by controlling anabolic processes in cells. mTOR exists in two distinct mTOR complexes known as mTORC1 and mTORC2 that reside mostly in cytoplasm. In our study, the biochemical characterization of mTOR led to discovery of its novel localization on nuclear envelope where it associates with a critical regulator of nuclear import Ran Binding Protein 2 (RanBP2). We show that association of mTOR with RanBP2 is dependent on the mTOR kinase activity that regulates the nuclear import of ribosomal proteins. The mTOR kinase inhibitors within thirty minutes caused a substantial decrease of ribosomal proteins in the nuclear but not cytoplasmic fraction. Detection of a nuclear accumulation of the GFP-tagged ribosomal protein rpL7a also indicated its dependence on the mTOR kinase activity. The nuclear abundance of ribosomal proteins was not affected by inhibition of mTOR Complex 1 (mTORC1) by rapamycin or deficiency of mTORC2, suggesting a distinctive role of the nuclear envelope mTOR complex in the nuclear import. Thus, we identified that mTOR in association with RanBP2 mediates the active nuclear import of ribosomal proteins.

Topics: Active Transport, Cell Nucleus; Cell Line, Tumor; Cell Nucleus; HEK293 Cells; HeLa Cells; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Molecular Chaperones; Multiprotein Complexes; Neoplasms; Nuclear Pore Complex Proteins; Ribosomal Proteins; Sirolimus; TOR Serine-Threonine Kinases

Curcumin, a specific secondary metabolite of Curcuma species, has potentials for a variety of beneficial health effects. It is nowadays used as a dietary supplement. Everolimus (EVL) is an immunosuppressant indicated for allograft rejection and cancer therapy, but with narrow therapeutic window. EVL is a substrate of P-glycoprotein (P-gp) and cytochrome P450 3A4 (CYP3A4). This study investigated the effect of coadministration of curcumin on the pharmacokinetics of EVL in rats and the underlying mechanisms. EVL (0.5 mg/kg) was orally administered without and with 50 and 100 mg/kg of curcumin, respectively, in rats. Blood samples were collected at specific time points and EVL concentrations in blood were determined by QMS immunoassay. The underlying mechanisms were evaluated using cell model and recombinant CYP 3A4 isozyme. The results indicated that 50 and 100 mg/kg of curcumin significantly decreased the AUC0-540 of EVL by 70.6% and 71.5%, respectively, and both dosages reduced the Cmax of EVL by 76.7%. Mechanism studies revealed that CYP3A4 was markedly activated by curcumin metabolites, which apparently overrode the inhibition effects of curcumin on P-gp. In conclusion, oral intake of curcumin significantly decreased the bioavailability of EVL, a probe substrate of P-gp/CYP 3A4, mainly through marked activation on CYP 3A4.

Topics: Administration, Oral; Animals; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Availability; Cell Line, Tumor; Curcumin; Cytochrome P-450 CYP3A; Drug Interactions; Everolimus; Humans; Neoplasms; Rats; Sirolimus

Oral tyrosine kinase inhibitors and mammalian target of rapamycin (mTOR) inhibitors are indicated in several types of cancer. They are usually administered at a fixed dose. In recent years, observational studies have reported on the wide variability in exposure to these new drugs, and the relationship between clinical response (efficacy and toxicity) and target plasma concentrations. Additionally, we are gaining insight into different food and drug interactions with these new drugs. On the basis of current drug monitoring, advice can be given on individual dosing of pazopanib in metastatic renal cell cancer (mRCC), sunitinib in mRCC and gastrointestinal stromal tumor (GIST), and imatinib in GIST.

Topics: Administration, Oral; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Dose-Response Relationship, Drug; Drug Interactions; Humans; Neoplasms; Protein Kinase Inhibitors; Sirolimus; Treatment Outcome

Topics: Animals; Antibiotics, Antineoplastic; Cell Line, Tumor; Gene Expression Regulation; Humans; Mice; MicroRNAs; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

As progression-free survival (PFS) has become increasingly used as the primary endpoint in oncology phase III trials, the U.S. Food and Drug Administration (FDA) has generally required a complete-case blinded independent central review (BICR) of PFS to assess and reduce potential bias in the investigator or local site evaluation. However, recent publications and FDA analyses have shown a high correlation between local site evaluation and BICR assessments of the PFS treatment effect, which questions whether complete-case BICR is necessary. One potential alternative is to use BICR as an audit tool to detect evaluation bias in the local site evaluation. In this article, the performance characteristics of two audit methods proposed in the literature are evaluated on 26 prospective, randomized phase III registration trials in nonhematologic malignancies. The results support that a BICR audit to assess potential bias in the local site evaluation is a feasible approach. However, implementation and logistical challenges need further consideration and discussion.

Topics: Algorithms; Bias; Carcinoid Tumor; Clinical Audit; Clinical Trials, Phase III as Topic; Disease Progression; Disease-Free Survival; Endpoint Determination; Everolimus; Humans; Immunosuppressive Agents; Neoplasms; Outcome Assessment, Health Care; Randomized Controlled Trials as Topic; Reproducibility of Results; Sarcoma; Sirolimus

The Murine Double Minute 2 (MDM2) protein is a key regulator of cell proliferation and apoptosis that acts primarily by inhibiting the p53 tumor suppressor. Similarly, the PI3-Kinase (PI3K)/AKT pathway is critical for growth factor-mediated cell survival. Additionally, it has been reported that AKT can directly phosphorylate and activate MDM2. In this study, we show that IGF-1 up-regulates MDM2 protein levels in a PI3K/AKT-dependent manner. Inhibition of mTOR by rapamycin or expression of a dominant negative eukaryotic initiation factor 4E binding protein 1 (4EBP1) mutant protein, as well as ablation of eukaryotic initiation factor 4E (eIF4E), efficiently abolishes IGF-1-mediated up-regulation of MDM2. In addition, we show that rapamycin effectively inhibits MDM2 expression and sensitizes cancer cells to chemotherapy. Taken together, this study reveals a novel mechanism by which IGF-1 activates MDM2 via the mTOR pathway, and that pharmacologic inhibition of mTOR combined with chemotherapy may be more effective in treatment of a subset of cancers harboring increased MDM2 activation.

Topics: Antibiotics, Antineoplastic; Apoptosis; Cell Line, Tumor; Doxorubicin; Humans; Insulin-Like Growth Factor I; Neoplasms; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-mdm2; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Up-Regulation

If life were created by intelligent design, we would indeed age from accumulation of molecular damage. Repair is costly and limited by energetic resources, and we would allocate resources rationally. But, albeit elegant, this design is fictional. Instead, nature blindly selects for short-term benefits of robust developmental growth. "Quasi-programmed" by the blind watchmaker, aging is a wasteful and aimless continuation of developmental growth, driven by nutrient-sensing, growth-promoting signaling pathways such as MTOR (mechanistic target of rapamycin). A continuous post-developmental activity of such gerogenic pathways leads to hyperfunctions (aging), loss of homeostasis, age-related diseases, non-random organ damage and death. This model is consistent with a view that (1) soma is disposable, (2) aging and menopause are not programmed and (3) accumulation of random molecular damage is not a cause of aging as we know it.

Topics: Aging; Female; Humans; Male; Menopause; Neoplasms; Religious Philosophies; Selection, Genetic; Sirolimus; TOR Serine-Threonine Kinases

Topics: Aging; Animals; Cellular Senescence; Gene Expression Regulation; Humans; Hypoglycemic Agents; Immunosuppressive Agents; Metformin; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Autophagy is frequently activated in radioresistant cancer cells where it provides a cell survival strategy. The mTOR inhibitor rapamycin activates autophagy but paradoxically it also enhances radiosensitivity. In this study, we investigated the mechanisms of these opposing actions in radiation-resistant glioma or parotid carcinoma cells. Radiation treatment transiently enhanced autophagic flux for a period of 72 hours in these cells and treatment with rapamycin or the mTOR inhibitor PP242 potentiated this effect. However, these treatments also increased heterochromatin formation, irreversible growth arrest, and premature senescence, as defined by expression of senescence-associated β-galactosidase activity. This augmentation in radiosensitivity seemed to result from a restoration in the activity of the tumor suppressor RB and a suppression of RB-mediated E2F target genes. In tumor xenografts, we showed that administering rapamycin delayed tumor regrowth after irradiation and increased senescence-associated β-galactosidase staining in the tumor. Our findings suggest that a potent and persistent activation of autophagy by mTOR inhibitors, even in cancer cells where autophagy is occurring, can trigger premature senescence as a method to restore radiosensitivity.

Topics: Aging; Animals; Autophagy; beta-Galactosidase; Cell Line, Tumor; Cell Survival; Down-Regulation; Heterochromatin; HT29 Cells; Humans; Indoles; Male; Mice; Mice, Nude; Neoplasms; Parotid Neoplasms; Purines; Radiation Tolerance; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

Autophagy is a catabolic process activated by stress conditions and nutrient deprivation, to which it reacts by promoting the degradation of damaged organelles and misfolded/aggregated proteins, as well as generating new energetic pools. Paradoxically, in cancer cells, which signal the dangerous microenvironment occurring during clinical therapies, autophagy could promote their proliferation and sustain drug resistance. Special attention is given to autophagy manipulation in order to counteract drug resistance of cancer cells. This article describes the basic properties of autophagy and focuses on the strategies of manipulating it.

Topics: Antineoplastic Agents; Apoptosis; Autophagy; Drug Resistance, Neoplasm; Humans; Neoplasms; Protease Inhibitors; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Sirolimus; TOR Serine-Threonine Kinases

In multicellular organisms, cell division is regulated by growth factors (GFs). In the absence of GFs, cells exit the cell cycle at a site in G1 referred to as the restriction point (R) and enter a state of quiescence known as G0. Additionally, nutrient availability impacts on G1 cell cycle progression. While there is a vast literature on G1 cell cycle progression, confusion remains - especially with regard to the temporal location of R relative to nutrient-mediated checkpoints. In this report, we have investigated the relationship between R and a series of metabolic cell cycle checkpoints that regulate passage into S-phase.. We used double-block experiments to order G1 checkpoints that monitor the presence of GFs, essential amino acids (EEAs), the conditionally essential amino acid glutamine, and inhibition of mTOR. Cell cycle progression was monitored by uptake of [(3)H]-thymidine and flow cytometry, and analysis of cell cycle regulatory proteins was by Western-blot.. We report here that the GF-mediated R can be temporally distinguished from a series of late G1 metabolic checkpoints mediated by EAAs, glutamine, and mTOR - the mammalian/mechanistic target of rapamycin. R is clearly upstream from an EAA checkpoint, which is upstream from a glutamine checkpoint. mTOR is downstream from both the amino acid checkpoints, close to S-phase. Significantly, in addition to GF autonomy, we find human cancer cells also have dysregulated metabolic checkpoints.. The data provided here are consistent with a GF-dependent mid-G1 R where cells determine whether it is appropriate to divide, followed by a series of late-G1 metabolic checkpoints mediated by amino acids and mTOR where cells determine whether they have sufficient nutrients to accomplish the task. Since mTOR inhibition arrests cells the latest in G1, it is likely the final arbiter for nutrient sufficiency prior to committing to replicating the genome.

Topics: Amino Acids; Animals; Cell Line, Tumor; G1 Phase Cell Cycle Checkpoints; Humans; Intercellular Signaling Peptides and Proteins; Mammals; Neoplasms; Phosphorylation; Resting Phase, Cell Cycle; Sirolimus; Time Factors; TOR Serine-Threonine Kinases

Restenosis (renarrowing of the blood vessel wall) and cancer are two different pathologies that have drawn extensive research attention over the years. Antiproliferative drugs such as paclitaxel inhibit cell proliferation and are therefore effective in the treatment of cancer as well as neointimal hyperplasia, which is known to be the main cause of restenosis. Antiproliferative drugs are highly hydrophobic and their release from porous biodegradable structures is therefore advantageous. The release profiles of four antiproliferative drugs from highly porous polymeric structures were studied in this study in light of the physical properties of both the host polymers and the drug molecules, and a qualitative model was developed. The chemical structure of the polymer chain directly affects the drug release profile through water uptake in the early stages or degradation and erosion in later stages. It also affects the release profile indirectly, through the polymer's 3D porous structure. However, this effect is minor. The drug volume and molecular area dominantly affect its diffusion rate from the 3D porous structure and the drug's solubility parameter compared with that of the host polymer has some effect on the drug release profile. This model can also be used to describe release mechanisms of other hydrophobic drugs from porous structures.

Topics: Antineoplastic Agents; Biocompatible Materials; Drug-Eluting Stents; Farnesol; Humans; Models, Molecular; Neoplasms; Paclitaxel; Polyglactin 910; Porosity; Salicylates; Sirolimus; Solubility

Mammalian target of rapamycin (mTOR) inhibitors possess anticancer properties potentially useful in reducing posttransplantation malignancy. Besides controlling tumor-sensitive proliferative and angiogenic effects, mTOR influences transcription factors T-bet and Eomesodermin (Eomes) in CD8 cytotoxic T cells (Tc), which are key in rejecting tumors, and allografts.. To study the role of mTOR in tumor and transplant immunity in an antigen-specific way, we used T-cell receptor transgenic B6.OTI recipients, B6.OVA.TG donors, and OVA-B16F10 melanoma cells. For tracking color-coded OTI-Tc cells associated with antitumor and alloimmunity in vivo, CD8-OTI transgenic reporter mice were created by crossbreeding DsRed-expressing B6.Nagy mice with B6.OTI mice.. The role of mTOR in regulating the differentiation and function of alloreactive Tc cells in vitro was explored by stimulating OTI-Tc cells with ovalbumin-transgenic antigen-presenting cells in the presence of rapamycin or tacrolimus. Rapamycin, but not tacrolimus, induced a pro-antitumor phenotypic shift from CD62LCD44 effector memory Tc cells to CD62LCD44 central memory Tc cells, which featured up-regulated levels of T-bet and Eomes and preserved levels of interferon-γ and perforin. For future investigations, an in vivo model was established whereby DsRedOTI-Tc cells adoptively transferred into B6 mice bearing either a ovalbumin-transgenic mouse skin transplant or OVA-B16F10 tumor could be traced by fluorescence-activated cell sorting analysis as effector or memory Tc cells in transplant and tumor tissues.. mTOR, but not calcineurin, inhibition spares antitumoral memory Tc cells by distinctively regulating T-bet and Eomes. This finding is now testable in a new tumor transplant model, which incorporates DsRedOTI-Tc cell tracing, opening the way to study the differential effects of immunosuppressants in posttransplantation malignancy.

Topics: Animals; Calcineurin Inhibitors; CD8-Positive T-Lymphocytes; Immunologic Memory; Immunosuppressive Agents; Interleukin-12; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Neoplasms; Sirolimus; T-Box Domain Proteins; TOR Serine-Threonine Kinases; Transplantation, Homologous

Topics: Antibiotics, Antineoplastic; Antineoplastic Agents; Clinical Trials as Topic; Humans; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

At present, 150 clinical trials are registered with the National Cancer Institute, which investigate the efficacy of inhibitors of the PI3K/Akt/mTOR pathway against multiple cancers. Efficacy varies not so much with drug action, but with tumor type, as different cancer types (and different pre-clinical models) exhibit widely differing susceptibilities to mTOR inhibitors, such as rapamycin. Viral cancers appear to be among the most mTOR-addicted and most rapamycin-sensitive cancers. We discuss the different mTOR inhibitors that are currently available and in clinical trials. We also speculate how the molecular makeup of viral cancers could guide the selection and use of known and novel mTOR inhibitors to treat virus-associated malignancies.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Virus Diseases

Topics: Adaptor Proteins, Signal Transducing; Antineoplastic Agents; Cell Cycle Proteins; Drug Resistance, Neoplasm; Everolimus; Humans; Neoplasms; Phosphoproteins; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6 Kinases; Sirolimus; Tacrolimus Binding Protein 1A; TOR Serine-Threonine Kinases

This retrospective single-center study evaluated long-term renal function after conversion from calcineurin inhibitors to sirolimus-based immunosuppression in kidney transplant recipients.. From 2001 to 2009, one hundred fifty kidney transplant recipients were converted from calcineurin inhibitors to sirolimus at least 3 months after transplant.. After a mean follow-up of 171 weeks, 56.7% of converted patients remained on sirolimus. The 5-year survival rate of the patients (including intent-to-treat) and grafts was 85.5% and 83.6%. Patients on sirolimus showed significant improvement in renal function with a creatinine clearance of 50.9 ± 20.7 and 52.9 ± 20.8 mL/minute at month 0 and month 24. Independent predictive factors associated with a stable estimated glomerular filtration rate at the last follow-up of sirolimus patients were (1) having a living donor, (2) absence of anti-HLA alloantibodies at month 0, and (3) cyclosporine versus tacrolimus used before conversion. Adverse effects were reported in 134 patients (89.3%). They included (1) hospitalization for infection (n=52), (2) de novo proteinuria (n=40), and (3) eight patients with biopsy-proven acute rejection. Sirolimus was stopped and replaced by calcineurin inhibitors in 37 patients after a mean of 16 months treatment. After stopping sirolimus, renal-allograft function remained stable at 2 years.. Conversion of calcineurin inhibitors to sirolimus in kidney transplant recipients was associated with improved renal function. The reintroduction of calcineurin inhibitors was safe in patients who were withdrawn from sirolimus owing to adverse effects.

Topics: Adult; Aged; Calcineurin Inhibitors; Cyclosporine; Enzyme Inhibitors; Female; Follow-Up Studies; Glomerular Filtration Rate; Graft Rejection; Graft Survival; Humans; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Neoplasms; Opportunistic Infections; Postoperative Complications; Proteinuria; Retrospective Studies; Sirolimus; Tacrolimus

Metformin has been reported to lower cancer incidence among type II diabetics. Metformin exhibits antiproliferative and antineoplastic effects associated with inhibition of mammalian target of rapamycin complex 1 (mTORC1), but the mechanisms are poorly understood. We provide a unique genome-wide analysis of translational targets of canonical mTOR inhibitors (rapamycin and PP242) compared with metformin, revealing that metformin controls gene expression at the level of mRNA translation to an extent comparable to that of canonical mTOR inhibitors. Importantly, metformin's antiproliferative activity can be explained by selective translational suppression of mRNAs encoding cell-cycle regulators via the mTORC1/eukaryotic translation initiation factor 4E-binding protein pathway. Thus, metformin selectively inhibits translation of mRNAs encoding proteins that promote neoplastic proliferation, which should facilitate studies on metformin and related biguanides in cancer prevention and treatment.

Topics: Analysis of Variance; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Humans; Indoles; Metformin; Microarray Analysis; Neoplasms; Protein Biosynthesis; Purines; Sirolimus; TOR Serine-Threonine Kinases

Using novel small-molecular inhibitors, we explored the feasibility of the class I PI3K/Akt/mTORC1 signaling pathway as a therapeutic target in canine oncology either by using pathway inhibitors alone, in combination or combined with conventional chemotherapeutic drugs in vitro.. We demonstrate that growth and survival of the cell lines tested are predominantly dependent on class I PI3K/Akt signaling rather than mTORC1 signaling. In addition, the newly developed inhibitors ZSTK474 and KP372-1 which selectively target pan-class I PI3K and Akt, respectively, and Rapamycin which has been well-established as highly specific mTOR inhibitor, decrease viability of canine cancer cell lines. All inhibitors demonstrated inhibition of phosphorylation of pathway members. Annexin V staining demonstrated that KP372-1 is a potent inducer of apoptosis whereas ZSTK474 and Rapamycin are weaker inducers of apoptosis. Simultaneous inhibition of class I PI3K and mTORC1 by ZSTK474 combined with Rapamycin additively or synergistically reduced cell viability whereas responses to the PI3K pathway inhibitors in combination with conventional drug Doxorubicin were cell line-dependent.. This study highlighted the importance of class I PI3K/Akt axis signaling in canine tumour cells and identifies it as a promising therapeutic target.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Survival; Dog Diseases; Dogs; Drug Synergism; Gene Expression Regulation, Neoplastic; Heterocyclic Compounds, 4 or More Rings; Humans; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; Tetrazoles; TOR Serine-Threonine Kinases; Triazines

Monitoring autophagic flux is important for the analysis of autophagy. Tandem fluorescent-tagged LC3 (mRFP-EGFP-LC3) is a convenient assay for monitoring autophagic flux based on different pH stability of EGFP and mRFP fluorescent proteins. However, it has been reported that there is still weak fluorescence of EGFP in acidic environments (pH between 4 and 5) or acidic lysosomes. So it is possible that autolysosomes are labeled with yellow signals (GFP(+)RFP(+) puncta), which results in misinterpreting autophagic flux results. Therefore, it is desirable to choose a monomeric green fluorescent protein that is more acid sensitive than EGFP in the assay of autophagic flux. Here, we report on an mTagRFP-mWasabi-LC3 reporter, in which mWasabi is more acid sensitive than EGFP and has no fluorescence in acidic lysosomes. Meanwhile, mTagRFP-mWasabi-LC3ΔG was constructed as the negative control for this assay. Compared with mRFP-EGFP-LC3, our results showed that this reporter is more sensitive and accurate in detecting the accumulation of autophagosomes and autolysosomes. Using this reporter, we find that high-dose rapamycin (30 μM) will impair autophagic flux, inducing many more autophagosomes than autolysosomes in HeLa cells, while low-dose rapamycin (500 nM) has an opposite effect. In addition, other chemical autophagy inducers (cisplatin, staurosporine and Z18) also elicit much more autophagosomes at high doses than those at low doses. Our results suggest that the dosage of chemical autophagy inducers would obviously influence autophagic flux in cells.

Topics: Animals; Autophagy; Cisplatin; Dose-Response Relationship, Drug; Embryo, Mammalian; Fibroblasts; Fluorescence; Green Fluorescent Proteins; HeLa Cells; Humans; Luminescent Proteins; Lysosomes; Mice; Microscopy, Confocal; Microtubule-Associated Proteins; Neoplasms; Recombinant Fusion Proteins; Red Fluorescent Protein; Sirolimus; Staurosporine

Zwitterionic oligopeptide liposomes (HHG2C(18)-L) containing a smart lipid (1,5-dioctadecyl-L-glutamyl 2-histidyl-hexahydrobenzoic acid, HHG2C(18)) are developed to overcome the barriers faced by anticancer drugs on the route from the site of injection into the body to the final antitumor target within transport steps with multiple physiological and biological barriers. HHG2C(18)-L show the multistage pH-responsive to the tumor cell (the mitochondria in this case). Their multistage pH response leads to more effective entry of the tumor cell, improved escape from the endolysosomes, and accumulation at the mitochondria (see picture).

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Humans; Hydrogen-Ion Concentration; Liposomes; Mice; Mitochondria; Neoplasms; Oligopeptides; Sirolimus; Tissue Distribution; Transplantation, Heterologous

Therapies directed against VEGF-A and its receptors are effective in treating many mouse tumors but have been less so in treating human cancer patients. To elucidate the reasons that might be responsible for this difference in response, we investigated the nature of the blood vessels that appear in human and mouse cancers and the tumor "surrogate" blood vessels that develop in immunodeficient mice in response to an adenovirus expressing VEGF-A(164). Both tumor and tumor surrogate blood vessels are heterogeneous and form by two distinct processes, angiogenesis and arterio-venogenesis. The first new angiogenic blood vessels to form are mother vessels (MV); MV arise from preexisting venules and capillaries and evolve over time into glomeruloid microvascular proliferations (GMP) and subsequently into capillaries and vascular malformations (VM). Arterio-venogenesis results from the remodeling and enlargement of preexisting arteries and veins, leading to the formation of feeder arteries (FA) and draining veins (DV) that supply and drain angiogenic vessels. Of these different blood vessel types, only the two that form first, MV and GMP, were highly responsive to anti-VEGF therapy, whereas "late"-formed capillaries, VM, FA and DV were relatively unresponsive. This finding may explain, at least in part, the relatively poor response of human cancers to anti-VEGF/VEGFR therapies, because human cancers, present for months or years prior to discovery, are expected to contain a large proportion of late-formed blood vessels. The future of anti-vascular cancer therapy may depend on finding new targets on "late" vessels, apart from those associated with the VEGF/VEGFR axis.

Topics: Angiogenesis Inhibitors; Animals; Antibiotics, Antineoplastic; Antibodies, Monoclonal, Humanized; Bevacizumab; Humans; Mice; Molecular Targeted Therapy; Neoplasms; Neovascularization, Pathologic; Receptors, Vascular Endothelial Growth Factor; Recombinant Fusion Proteins; Sirolimus; Vascular Endothelial Growth Factor A

Pancreatic cancer is a relatively rare malignancy with a very aggressive natural course, not restrained by the existing current treatments. At the 2012 American Society of Clinical Oncology (ASCO) Annual Meeting, the results of few phase I clinical studies on solid tumors and pancreatic cancer were presented. In particular, in the field of immunotherapy, a pilot phase I study tested for first time a carcinoembryonic antigen (CEA)-based vaccine (Abstract #2561) on patients with pancreatic adenocarcinoma and another one the optimal dose and efficacy of trabedersen, an inhibitor of tissue growth factor-beta 2 (TGF-β2) aiming to enhance antitumor immune responses (Abstract #4034). Other phase I studies explored the pharmacokinetic and pharmacodynamic properties of an oral gemcitabine pro-drug (LY2334737; Abstract #2554), or of the combination of gemcitabine with sirolimus (Abstract #3096) or the combination of gemcitabine with an inhibitor of mitogen-activated protein kinase (MAPK), extracellular signal-regulated protein kinase (ERK) (MEK 1/2; Abstract #4034).

Topics: Antineoplastic Combined Chemotherapy Protocols; Clinical Trials, Phase I as Topic; Deoxycytidine; Gemcitabine; Humans; Immunotherapy; Neoplasms; Pancreatic Neoplasms; Sirolimus

The nutrient-sensing mTOR (mammalian Target of Rapamycin) pathway regulates cellular metabolism, growth functions, and proliferation and is involved in age-related diseases including cancer, type 2 diabetes, neurodegeneration and cardiovascular disease. The inhibition of mTOR by rapamycin, or calorie restriction, has been shown to extend lifespan and delays tumorigenesis in several experimental models suggesting that rapamycin may be used for cancer prevention. This requires continuous long-term treatment making oral formulations the preferred choice of administration route. However, rapamycin by itself has very poor water solubility and low absorption rate. Here we describe pharmacokinetic and biological properties of novel nanoformulated micelles of rapamycin, Rapatar. Micelles of Rapatar were rationally designed to increase water solubility of rapamycin to facilitate oral administration and to enhance its absorption. As a result, bioavailability of Rapatar was significantly increased (up to 12%) compared to unformulated rapamycin, which concentration in the blood following oral administration remained below level of detection. We also demonstrated that the new formulation does not induce toxicity during lifetime administration. Most importantly, Rapatar extended the mean lifespan by 30% and delayed tumor development in highly tumor-prone p53-/- mice. Our data demonstrate that water soluble Rapatar micelles represent safe, convenient and efficient form of rapamycin suitable for a long-term treatment and that Rapatar may be considered for tumor prevention.

Topics: Animals; Antibiotics, Antineoplastic; Biological Availability; Female; Genes, p53; Homozygote; Longevity; Male; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; Nanostructures; Neoplasms; Sirolimus

Topics: Animals; Antineoplastic Agents; Disease Progression; Longevity; Mice; Mice, Knockout; Neoplasms; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Suppressor Protein p53

Topics: Age of Onset; Aging; Animal Diseases; Animals; Biomedical Research; Caloric Restriction; Cardiovascular Diseases; Female; Gene Expression Profiling; Geriatrics; Humans; Longevity; Macaca mulatta; Male; Mice; Models, Animal; Neoplasms; Oligonucleotide Array Sequence Analysis; Reproducibility of Results; Resveratrol; Sirolimus; Sirtuins; Somatomedins; Stilbenes; TOR Serine-Threonine Kinases

Epidermal growth factor receptor (EGFR) and mammalian target of rapamycin (mTOR) play important roles in tumor growth, which has stimulated efforts toward the design of targeted cancer therapeutics that inhibit their function. A growing body of literature indicates that EGFR and mTOR are also essential to support a functional innate immune response. Hence, although combination therapies that block both EGFR and mTOR may have improved activity against tumors, they may also place patients at risk of fulminant infections. We discuss data supporting this hypothesis.

Topics: Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Cetuximab; ErbB Receptors; Everolimus; Humans; Immunity, Innate; Neoplasms; Signal Transduction; Sirolimus; Toll-Like Receptor 3

Nimotuzumab, an anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody, has been used extensively in many solid tumors and confers significant survival advantage. The antibody has limited skin toxicity and is generally well tolerated. Similar to other anti-EGFR therapies, patients may relapse a few months after treatment. In this study we show for the first time, the use of Nimotuzumab along with Sirolimus has synergistic effect on tumor inhibition as compared with the drugs used individually, in Nimotuzumab responsive and nonresponsive cell lines. In vitro studies prove that while Sirolimus (25 nmol/L) affects the signal downstream to mammalian target of rapamycin (mTOR), Nimotuzumab (83 nmol/L) downregulates pTYR, pMAPK and pSTAT3 by 40%, 20% and 30%, respectively. The combination, targeting these two different signaling hubs, may be associated with the synergistic inhibition observed. In vivo, the use of half human therapeutic equivalent doses for both the drugs substantially reduces tumors established in nude as well as severe combined immunodeficiency (SCID) mice by EGFR overexpressing A-431 cells. The drug combination reduces cell proliferation and the expression of signal transduction molecules. Treated tumors are better differentiated as compared with those established in the control mice. Tumor microarray demonstrates that Nimotuzumab and the combination groups segregate independently to the Sirolimus and the control treatment. The combination uniquely downregulated 55% of the altered tumor genes, extending beyond the typical pathways associated with Nimotuzumab and Sirolimus downstream pathways inhibition. These results would suggest that this nontoxic drug combination improves therapeutic benefit even in patients with low-EGFR expression and severely immunocompromised because of their current medication.

Topics: Animals; Antibiotics, Antineoplastic; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Cell Proliferation; Drug Synergism; ErbB Receptors; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Mitogen-Activated Protein Kinases; Molecular Targeted Therapy; Neoplasm Transplantation; Neoplasms; Signal Transduction; Sirolimus; STAT3 Transcription Factor; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

We report here the discovery of a novel series of selective mTOR kinase inhibitors. A series of imidazo[4,5-b]pyrazin-2-ones, represented by screening hit 1, was developed into lead compounds with excellent mTOR potency and exquisite kinase selectivity. Potent compounds from this series show >1000-fold selectivity over the related PI3Kα lipid kinase. Further, compounds such as 2 achieve mTOR pathway inhibition, blocking both mTORC1 and mTORC2 signaling, in PC3 cancer cells as measured by inhibition of pS6 and pAkt (S473).

Topics: Antineoplastic Agents; Cell Line, Tumor; Drug Discovery; Humans; Models, Molecular; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyrazines; Signal Transduction; Structure-Activity Relationship; TOR Serine-Threonine Kinases

Unlike other immunosuppressive drugs including everolimus, cyclosporin A causes a dramatic increase of UV-induced skin cancer, a feature that is reminiscent of xeroderma pigmentosum (XP), where defective nucleotide excision repair (NER) of UV-induced DNA damage results in cutaneous carcinogenesis. The molecular basis of the clinically important differential activities of cyclosporin A and everolimus is still unclear. We measured post-UV cell survival of cyclosporin A- and everolimus-treated human fibroblasts and lymphoblasts using a cell proliferation assay (MTT). The cellular NER capacity was assessed by host cell reactivation. Using an ELISA and specific antibodies, cyclobutane pyrimidine and pyrimidine-6,4-pyrimidone photoproduct removal from the cellular genome was measured. The effect of calcineurin on NER was investigated using a calcineurin A expression vector and specific RNAi. Cyclosporin A led to a dose dependent decrease in post-UV cell survival, inhibited NER and blocked photoproduct removal. In contrast, none of these effects where seen in everolimus-treated cells. Overexpression of calcineurin A resulted in increased NER and complemented the Cyclosporin A-induced reduction of NER. Downregulation of calcineurin using RNAi inhibited NER comparable to cyclosporin A-treatment. We conclude that cyclosporin A, but not everolimus, leads to an increased skin cancer risk via a calcineurin signalling-dependent impairment of NER.

Topics: Calcineurin; Cell Line, Transformed; Cell Survival; Cyclosporine; DNA Repair; Everolimus; Fibroblasts; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Lymphocytes; Neoplasms; Phosphorylation; Pyrimidine Dimers; Ribosomal Protein S6 Kinases, 70-kDa; RNA, Small Interfering; Sirolimus; Transfection; Ultraviolet Rays

The mammalian target of rapamycin (mTOR) which is part of two functionally distinct complexes, mTORC1 and mTORC2, plays an important role in vascular endothelial cells. Indeed, the inhibition of mTOR with an allosteric inhibitor such as rapamycin reduces the growth of endothelial cell in vitro and inhibits angiogenesis in vivo. Recent studies have shown that blocking mTOR results in the activation of other prosurvival signals such as Akt or MAPK which counteract the growth inhibitory properties of mTOR inhibitors. However, little is known about the interactions between mTOR and MAPK in endothelial cells and their relevance to angiogenesis. Here we found that blocking mTOR with ATP-competitive inhibitors of mTOR or with rapamycin induced the activation of the mitogen-activated protein kinase (MAPK) in endothelial cells. Downregulation of mTORC1 but not mTORC2 had similar effects showing that the inhibition of mTORC1 is responsible for the activation of MAPK. Treatment of endothelial cells with mTOR inhibitors in combination with MAPK inhibitors reduced endothelial cell survival, proliferation, migration and tube formation more significantly than either inhibition alone. Similarly, in a tumor xenograft model, the anti-angiogenic efficacy of mTOR inhibitors was enhanced by the pharmacological blockade of MAPK. Taken together these results show that blocking mTORC1 in endothelial cells activates MAPK and that a combined inhibition of MAPK and mTOR has additive anti-angiogenic effects. They also provide a rationale to target both mTOR and MAPK simultaneously in anti-angiogenic treatment.

Topics: Angiogenesis Inhibitors; Animals; Butadienes; Cell Movement; Cell Proliferation; Cell Survival; Cells, Cultured; Endothelium, Vascular; Enzyme Inhibitors; Humans; Imidazoles; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Nude; Mitogen-Activated Protein Kinase Kinases; Morpholines; Multiprotein Complexes; Neoplasms; Neovascularization, Pathologic; Nitriles; Proteins; Pyrimidines; Quinolines; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

mTOR is a central mediator of cancer cell growth, but it also directs immune cell differentiation and function. On this basis, we had explored the hypothesis that mTOR inhibition can enhance cancer immunotherapy. Here, we report that a combination of αCD40 agonistic antibody and the ATP-competitive mTOR kinase inhibitory drug AZD8055 elicited synergistic antitumor responses in a model of metastatic renal cell carcinoma. In contrast to the well-established mTOR inhibitor rapamycin, AZD8055 increased the infiltration, activation, and proliferation of CD8(+) T cells and natural killer cells in liver metastatic foci when combined with the CD40 agonist. AZD8055/αCD40-treated mice also display an increased incidence of matured macrophages and dendritic cells compared with that achieved in mice by αCD40 or AZD8055 treatment alone. We found that the combination treatment also increased macrophage production of TNFα, which played an indispensable role in activation of the observed antitumor immune response. Levels of Th1 cytokines, including interleukin 12, IFN-γ, TNFα, and the Th1-associated chemokines RANTES, MIG, and IP-10 were each elevated significantly in the livers of mice treated with the combinatorial therapy versus individual treatments. Notably, the AZD8055/αCD40-induced antitumor response was abolished in IFN-γ(-/-) and CD40(-/-) mice, establishing the reliance of the combination therapy on host IFN-γ and CD40 expression. Our findings offer a preclinical proof of concept that, unlike rapamycin, the ATP-competitive mTOR kinase inhibitor AZD8055 can contribute with αCD40 treatment to trigger a restructuring of the tumor immune microenvironment to trigger regressions of an established metastatic cancer.

Topics: Animals; Antibodies; Antineoplastic Agents; CD40 Antigens; CD8-Positive T-Lymphocytes; Dendritic Cells; Humans; Immunotherapy; Interferon-gamma; Interleukin-12; Killer Cells, Natural; Lymphocyte Activation; Macrophage Activation; Mice; Mice, Inbred BALB C; Morpholines; Neoplasms; Neoplasms, Experimental; Sirolimus; TOR Serine-Threonine Kinases

Aberrant forms of the anaplastic lymphoma kinase (ALK) have been implicated in the pathogenesis of multiple human cancers, where ALK represents a rational therapeutic target in these settings. In this study, we report the identification and biological characterization of X-376 and X-396, two potent and highly specific ALK small molecule tyrosine kinase inhibitors (TKIs). In Ambit kinome screens, cell growth inhibition studies, and surrogate kinase assays, X-376 and X-396 were more potent inhibitors of ALK but less potent inhibitors of MET compared to PF-02341066 (PF-1066), an ALK/MET dual TKI currently in clinical trials. Both X-376 and X-396 displayed potent antitumor activity in vivo with favorable pharmacokinetic and toxicity profiles. Similar levels of drug sensitivity were displayed by the three most common ALK fusion proteins in lung cancer (EML4-ALK variants E13;A20, E20;A20, and E6b;A20) as well as a KIF5B-ALK fusion protein. Moreover, X-396 could potently inhibit ALK kinases engineered with two point mutations associated with acquired resistance to PF-1066, L1196M, and C1156Y, when engineered into an E13;A20 fusion variant. Finally, X-396 displayed synergistic growth inhibitory activity when combined with the mTOR inhibitor rapamycin. Our findings offer preclinical proof-of-concept for use of these novel agents to improve therapeutic outcomes of patients with mutant ALK-driven malignancies.

Topics: Anaplastic Lymphoma Kinase; Animals; Brain; Cell Line, Tumor; Drug Synergism; Female; Humans; Isoenzymes; Male; Mice; Mice, Inbred C57BL; Mice, Nude; Models, Molecular; Neoplasms; Point Mutation; Protein Kinase Inhibitors; Pyridazines; Receptor Protein-Tyrosine Kinases; Sirolimus; TOR Serine-Threonine Kinases

Topics: Animals; Antibiotics, Antineoplastic; Humans; Neoplasms; Protein Kinase Inhibitors; Sirolimus; TOR Serine-Threonine Kinases

To date cancer is considered as one of the most devastating diseases due to its high rate of mortality. Preclinical studies have demonstrated that the Akt/mTOR (mammalian target of rapamycin) pathway is activated in cancers and inhibition of this pathway has great potential in anti-cancer therapy. Rapamycin, one of the most potent anti-cancer drugs, blocks Akt/mTOR function and has anti-proliferative activity in several cancers. To circumvent problems associated with rapamycin due to its poor water solubility, poor oral bioavailability, low accessibility to cancer tissues and systemic toxicity, rapamycin-loaded cubic nanoparticles (NP) were formulated with vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) as an emulsifier for oral delivery. Cubic NP were characterised and these particles demonstrated better cytotoxicity and apoptosis compared with native rapamycin under in vitro conditions due to their enhanced cellular uptake. The molecular impact of particulate systems on the Akt/mTOR pathway were elucidated by immunoblotting. Down-regulation of different anti-apoptotic genes of this pathway indicates activation of apoptotic signals leading to MIA PaCa cell death. An in vivo study demonstrated enhanced bioavailability of rapamycin in cubic NP in comparison with native rapamycin in a mouse model with no toxicity and good biocompatibility of void cubic NP at a higher dose of oral administration. Thus, rapamycin-loaded cubic NP can be used as an effective drug delivery system to produce better rapamycin therapeutics for the treatment of cancers.

Topics: Animals; Apoptosis; Biocompatible Materials; Blotting, Western; Cell Line, Tumor; Chemical Phenomena; Coloring Agents; Coumarins; Flow Cytometry; Humans; Inhibitory Concentration 50; Membrane Potential, Mitochondrial; Mice; Microscopy, Confocal; Mitogens; Nanoparticles; Neoplasms; Particle Size; Proto-Oncogene Proteins c-akt; Sirolimus; Spectroscopy, Fourier Transform Infrared; Subcellular Fractions; Time Factors; TOR Serine-Threonine Kinases

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Benzenesulfonates; Bevacizumab; Cetuximab; Colonic Neoplasms; Diagnosis, Differential; Dose-Response Relationship, Drug; Drug Delivery Systems; Drug Eruptions; ErbB Receptors; Erlotinib Hydrochloride; Everolimus; Facial Dermatoses; Humans; Indoles; Liver Neoplasms; Male; Middle Aged; Neoplasms; Niacinamide; Phenylurea Compounds; Pyridines; Pyrroles; Quinazolines; Sirolimus; Sorafenib; Sunitinib; Trastuzumab

Increased plasma levels of adiponectin, metformin therapy of diabetes, rapamycin administration in transplant patients, and lifelong consumption of low-protein plant-based diets have all been linked to decreased risk for various cancers. These benefits may be mediated, at least in part, by down-regulated activity of the mTORC1 complex, a key regulator of protein translation. By boosting the effective availability of the translation initiator eIF4E, mTORC1 activity promotes the translation of a number of "weak" mRNAs that code for proteins, often up-regulated in cancer, that promote cellular proliferation, invasiveness, and angiogenesis, and that abet cancer promotion and chemoresistance by opposing apoptosis. Measures which inhibit eIF4E activity, either directly or indirectly, may have utility not only for cancer prevention, but also for the treatment of many cancers in which eIF4E drives malignancy. Since eIF4E is overexpressed in many cancers, strategies which target eIF4E directly--some of which are now being assessed clinically--may have the broadest efficacy in this regard. Many of the "weak" mRNAs coding for proteins that promote malignant behavior or chemoresistance are regulated transcriptionally by NF-kappaB and/or Stat3, which are active in a high proportion of cancers; thus, regimens concurrently targeting eIF4E, NF-kappaB, and Stat3 may suppress these proteins at both the transcriptional and translational levels, potentially achieving a very marked reduction in their expression.

Topics: Adiponectin; Diet, Vegetarian; Dietary Proteins; Down-Regulation; Humans; Mechanistic Target of Rapamycin Complex 1; Metformin; Multiprotein Complexes; Neoplasms; Proteins; Sirolimus; TOR Serine-Threonine Kinases

Anti-cancer agents that inhibit the mTOR pathway are associated with a number of unique toxicities, with one of the most significant and potentially dose-limiting being stomatitis. The objective of this study was to report the clinical features and management outcomes of a series of cancer patients who developed painful mTOR inhibitor-associated stomatitis (mIAS). Seventeen cancer patients developed mIAS while being treated with everolimus- or ridaforolimus-containing protocols at the Dana-Farber Cancer Institute and were referred to the oral medicine clinic for evaluation and management. Clinical characteristics, toxicity management, and outcomes were summarized. In addition, the frequency and rationale for dose reductions and therapy discontinuation were assessed. The median duration of mTOR inhibitor therapy was 80 days (range 9-187 days). The median time to development of mouth ulcers was 10 days (range 4-25 days). Five patients required protocol-directed dose reductions due to grades 2 and 3 stomatitis and one patient discontinued cancer treatment due to mouth ulcers. Clinical improvement and pain relief was reported in 86.6% of patients following topical, intralesional, or systemic corticosteroid therapy, with side effects limited to secondary candidiasis (n=2). Mouth ulcers are a common and potentially dose limiting toxicity associated with the use of mTOR inhibitors in cancer treatment. This case series demonstrates that local and systemic corticosteroid therapy is an effective approach to managing patients with symptomatic mIAS. Prospective studies are necessary to evaluate the effectiveness of treatment and prevention strategies with the ultimate goal of improving overall cancer treatment outcomes.

Topics: Adrenal Cortex Hormones; Adult; Aged; Everolimus; Female; Humans; Male; Middle Aged; Neoplasms; Retrospective Studies; Sirolimus; Stomatitis; TOR Serine-Threonine Kinases; Treatment Outcome

Topics: Antibiotics, Antineoplastic; Calcineurin Inhibitors; Contraindications; Dose-Response Relationship, Drug; Drug Interactions; Drug Substitution; Graft Rejection; Humans; Immunosuppressive Agents; Kidney Function Tests; Kidney Transplantation; Neoplasms; Prognosis; Randomized Controlled Trials as Topic; Sirolimus

Telomeres are specialized DNA-protein structures at the ends of eukaryotic chromosomes. Telomeric DNA is synthesized by telomerase, which is expressed only at the early stages of development [1, 2]. To become malignant, any cell has to be able to replenish telomeres [3]. Thus, understanding how telomere length is monitored has significant medical implications, especially in the fields of aging and cancer. In yeast, telomerase is constitutively active. A large network of genes participates in controlling telomere length [4-8]. Tor1 and Tor2 (targets of rapamycin [9]) are two similar kinases that regulate cell growth [10]. Both can be found as part of the TOR complex 1 (TORC1 [11]), which coordinates the response to nutrient starvation and is sensitive to rapamycin [12]. The rapamycin-insensitive TOR complex 2 (TORC2) contains only Tor2 and regulates actin cytoskeleton polarization [13]. Here we provide evidence for a role of TORC1 in telomere shortening upon starvation in yeast cells. The TORC1 signal is transduced by the Gln3/Gat1/Ure2 pathway, which controls the levels of the Ku heterodimer, a telomere regulator. We discuss the potential implications for the usage of rapamycin as a therapeutic agent against cancer and the effect that calorie restriction may have on telomere length.

Topics: Caloric Restriction; DNA-Binding Proteins; GATA Transcription Factors; Glutathione Peroxidase; Neoplasms; Prions; RNA-Binding Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Signal Transduction; Sirolimus; Species Specificity; Telomere; Telomere Shortening; Transcription Factors

Topics: AMP-Activated Protein Kinases; Antibiotics, Antineoplastic; DNA Glycosylases; Humans; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases

Neoangiogenesis plays an important role in tumor growth and metastasis. Evaluation of new anti-angiogenic targets may broaden the armament for future therapeutic concepts. Focal adhesion kinase (FAK), expressed in endothelial and tumor cells, is essential for adhesion and mobility of adherent cells. In the current study we analyzed the anti-angiogenic properties of the FAK inhibitor TAE226 on the proliferation of blood outgrowth endothelial cell (OEC) and differentiation of endothelial progenitor cells (EPC), derived from peripheral blood CD133(+) cells, tube formation and on neovascularization in a HT29 xenotransplant model. The effects of TAE226 were compared to those of the rapamycin analogue RAD001. The combination of both drugs was also studied. We showed that HT29 tumor cells and OEC were most sensitive to the action of TAE226 compared to EPC in vitro. In contrast, RAD001 affected the proliferation of both types of endothelial cells stronger than that of HT29 cells. Furthermore we could show that TAE226 inhibited tube formation in a dose dependent manner. In a HT29 subcutaneous tumor model TAE226 and RAD001 diminished MVD at commonly employed doses to a similar degree. Combination of both compounds did not show synergy in vitro or in vivo. Since TAE226 has been shown to inhibit the PI3 kinase, Akt kinase, mTor pathway, addition of RAD001 may not increase this effect. In conclusion, we have shown that treatment with TAE leads to a reduction of neoangiogenesis in vitro and in a mouse model. The effects are mediated by inhibition of angiogenesis and vasculogenic OEC and EPC.

Topics: Animals; Blood Vessels; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Endothelial Cells; Everolimus; Focal Adhesion Protein-Tyrosine Kinases; Humans; Mice; Mice, SCID; Morpholines; Neoplasms; Neovascularization, Pathologic; Organogenesis; Protein Kinase Inhibitors; Sirolimus

Mammalian target of rapamycin (mTOR) inhibitors may have efficacy as an intervention for advanced malignancies. Oral ulceration (OU), reported as mucositis, has been a dose-limiting toxicity for this new class of agents. An analysis of the appearance, course, and toxicity associations of mTOR inhibitor-associated stomatitis (mIAS) demonstrated that the condition is distinct from conventional mucositis (CM) and more closely resembles aphthous stomatitis.. Safety data from 78 solid tumor patients enrolled in 2 Phase 1, multicenter trials of the mTOR inhibitor deforolimus (AP23573, MK-8669) were evaluated. Adverse events (AEs) based on National Cancer Institute Common Toxicity Criteria for National Cancer Institute Common Terminology Criteria for Adverse Events (version 3.0) criteria were coded, consolidated, and stratified according to the presence or absence and duration of concordant OU. The relation between OU and other AEs was analyzed.. Treatment-emergent AEs were reported in 91% of 78 study participants. OUs were reported in 66%, appeared within 5 days of deforolimus administration, and were discrete, ovoid, superficial, well demarcated, and surrounded by an erythematous halo. Their clinical appearance and distribution were similar to that of aphthous stomatitis but inconsistent with CM. Patients with OU were more likely to have nonspecific rashes and acneiform dermatitis but not gastrointestinal AEs.. OU associated with mTOR inhibitor therapy differed from CM. Lesions more closely resembled those of aphthous stomatitis. The lack of other gastrointestinal involvement but the presence of a higher incidence of concomitant cutaneous AEs provided additional evidence to suggest a distinction between mIAS and CM. Treatment strategies for aphthous stomatitis may be a rational approach for the prevention and control of mIAS.

Topics: Adult; Aged; Antineoplastic Agents; Clinical Trials, Phase I as Topic; Female; Humans; Intracellular Signaling Peptides and Proteins; Male; Middle Aged; Mucositis; Neoplasms; Protein Serine-Threonine Kinases; Sirolimus; Stomatitis; TOR Serine-Threonine Kinases

Aberrant activation of Akt plays a pivotal role in cancer development. ATM, a protein deficient in patients with ataxia-telangiectasia disease, is traditionally considered as a nuclear protein kinase that functions as a signal transducer in response to DNA damage. It has recently been shown that ATM is also a cytoplasmic protein that mediates the full activation of Akt in response to insulin. Our study shows that a specific ATM inhibitor, KU-55933, blocks the phosphorylation of Akt induced by insulin and insulin-like growth factor I in cancer cells that exhibit abnormal Akt activity. Moreover, KU-55933 inhibits cancer cell proliferation by inducing G(1) cell cycle arrest. It does so through the downregulation of the synthesis of cyclin D1, a protein known to be elevated in a variety of tumors. In addition, KU-55933 treatment during serum starvation triggers apoptosis in these cancer cells. Our results suggest that KU-55933 may be a novel chemotherapeutic agent targeting cancer resistant to traditional chemotherapy or immunotherapy due to aberrant activation of Akt. Furthermore, KU-55933 completely abrogates rapamycin-induced feedback activation of Akt. Combination of KU-55933 and rapamycin not only induces apoptosis, which is not seen in cancer cells treated only with rapamycin, but also shows better efficacy in inhibiting cancer cell proliferation than each drug alone. Therefore, combining KU-55933 with rapamycin may provide a highly effective approach for improving mammalian target of rapamycin-targeted anticancer therapy that is currently hindered by rapamycin-induced feedback activation of Akt.

Topics: Adaptor Proteins, Signal Transducing; Animals; Apoptosis; Ataxia Telangiectasia Mutated Proteins; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Cyclin D1; DNA-Binding Proteins; Down-Regulation; Drug Screening Assays, Antitumor; Drug Synergism; Enzyme Activation; Fibroblasts; G1 Phase; Humans; Insulin; Intercellular Signaling Peptides and Proteins; Mice; Morpholines; Neoplasms; Peptide Chain Initiation, Translational; Phosphoproteins; Phosphorylation; Protein Kinase Inhibitors; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Pyrones; Sirolimus; Transcription, Genetic; Tumor Suppressor Proteins

The mammalian target of rapamycin (mTOR) is a major component of the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway that is dysregulated in 50% of all human malignancies. Rapamycin and its analogues (rapalogs) partially inhibit mTOR through allosteric binding to mTOR complex 1 (mTORC1) but not mTOR complex 2 (mTORC2), an emerging player in cancer. Here, we report WYE-125132 (WYE-132), a highly potent, ATP-competitive, and specific mTOR kinase inhibitor (IC(50): 0.19 +/- 0.07 nmol/L; >5,000-fold selective versus PI3Ks). WYE-132 inhibited mTORC1 and mTORC2 in diverse cancer models in vitro and in vivo. Importantly, consistent with genetic ablation of mTORC2, WYE-132 targeted P-AKT(S473) and AKT function without significantly reducing the steady-state level of the PI3K/PDK1 activity biomarker P-AKT(T308), highlighting a prominent and direct regulation of AKT by mTORC2 in cancer cells. Compared with the rapalog temsirolimus/CCI-779, WYE-132 elicited a substantially stronger inhibition of cancer cell growth and survival, protein synthesis, cell size, bioenergetic metabolism, and adaptation to hypoxia. Oral administration of WYE-132 to tumor-bearing mice showed potent single-agent antitumor activity against MDA361 breast, U87MG glioma, A549 and H1975 lung, as well as A498 and 786-O renal tumors. An optimal dose of WYE-132 achieved a substantial regression of MDA361 and A549 large tumors and caused complete regression of A498 large tumors when coadministered with bevacizumab. Our results further validate mTOR as a critical driver for tumor growth, establish WYE-132 as a potent and profound anticancer agent, and provide a strong rationale for clinical development of specific mTOR kinase inhibitors as new cancer therapy.

Topics: Animals; Apoptosis; Cell Cycle; Cell Growth Processes; Cell Hypoxia; Female; Humans; Intracellular Signaling Peptides and Proteins; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Neoplasms; Phenylurea Compounds; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Proteins; Proto-Oncogene Proteins c-akt; Pyrazoles; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Topics: Aging; Animals; Antifungal Agents; Cell Proliferation; Disease; Drug Administration Schedule; Geriatrics; Humans; Immunosuppressive Agents; Intracellular Signaling Peptides and Proteins; Longevity; Metabolic Diseases; Neoplasms; Primary Prevention; Protein Serine-Threonine Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Cancer progression is often associated with the formation of malignant effusions. Vascular endothelial growth factor (VEGF) is a major regulator of vascular permeability and has been implicated as mediator of tumor progression. We examined the production and secretion of VEGF(165) in various primary cancer cells derived from malignant effusions, and the role of exogenous VEGF(165) as a mediator of effusion formation. VEGF(165) was constantly secreted by all cultured tumor cells in an mTOR-dependent manner, as it was inhibited by the mTOR inhibitor rapamycin. Secreted VEGF(165) showed functional activity by inducing endothelial leakiness and tumor cell-transendothelial migration in vitro, effects which could be reverted by the anti-VEGF antibody bevacizumab. Thus, mTOR inhibitors as well as bevacizumab should be considered as potential agents in cancer patients suffering from malignant effusions.

Topics: Angiogenesis Inhibitors; Antibiotics, Antineoplastic; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Apoptosis; Bevacizumab; Cell Culture Techniques; Cell Line, Tumor; Cell Movement; Endothelium; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; Neoplasms; Protein Serine-Threonine Kinases; Recombinant Proteins; Sirolimus; TOR Serine-Threonine Kinases; Vascular Endothelial Growth Factor A

Viruses have evolved an assortment of mechanisms for regulating the Akt signaling pathway to establish a cellular environment more favorable for viral replication. Myxoma virus (MYXV) is a rabbit-specific poxvirus that encodes many immunomodulatory factors, including an ankyrin repeat-containing host range protein termed M-T5 that functions to regulate tropism of MYXV for rabbit lymphocytes and certain human cancer cells. MYXV permissiveness in these human cancer cells is dependent upon the direct interaction between M-T5 and Akt, which has been shown to induce the kinase activity of Akt. In this study, an array of compounds that selectively manipulate Akt signaling was screened and we show that only a subset of Akt inhibitors significantly decreased the ability of MYXV to replicate in previously permissive human cancer cells. Furthermore, reduced viral replication efficiency was correlated with lower levels of phosphorylated Akt. In contrast, the PP2A-specific phosphatase inhibitor okadaic acid promoted increased Akt kinase activation and rescued MYXV replication in human cancer cells that did not previously support viral replication. Finally, phosphorylation of Akt at residue Thr308 was shown to dictate the physical interaction between Akt and M-T5, which then leads to phosphorylation of Ser473 and permits productive MYXV replication in these human cancer cells. The results of this study further characterize the mechanism by which M-T5 exploits the Akt signaling cascade and affirms this interaction as a major tropism determinant that regulates the replication efficiency of MYXV in human cancer cells.

Topics: Cell Line, Tumor; Fingolimod Hydrochloride; Humans; Intracellular Signaling Peptides and Proteins; Myxoma virus; Neoplasms; Okadaic Acid; Phosphoric Monoester Hydrolases; Phosphorylation; Propylene Glycols; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; Sphingosine; TOR Serine-Threonine Kinases; Viral Proteins; Viral Tropism; Virus Replication

Numerous mechanism-based anticancer drugs that target the phosphatidylinositol 3-kinase (PI3K) pathway are in clinical trials. However, it remains challenging to assess responses by traditional imaging methods. Here, we show for the first time the efficacy of hyperpolarized (13)C magnetic resonance spectroscopy (MRS) in detecting the effect of PI3K inhibition by monitoring hyperpolarized [1-(13)C]lactate levels produced from hyperpolarized [1-(13)C]pyruvate through lactate dehydrogenase (LDH) activity. In GS-2 glioblastoma cells, PI3K inhibition by LY294002 or everolimus caused hyperpolarized lactate to drop to 42 +/- 12% and to 76 +/- 5%, respectively. In MDA-MB-231 breast cancer cells, hyperpolarized lactate dropped to 71 +/- 15% after treatment with LY294002. These reductions were correlated with reductions in LDH activity to 48 +/- 4%, 63 +/- 4%, and 69 +/- 12%, respectively, and were associated with a drop in levels of LDHA mRNA and LDHA and hypoxia-inducible factor-1alpha proteins. Supporting these findings, tumor growth inhibition achieved by everolimus in murine GS-2 xenografts was associated with a drop in the hyperpolarized lactate-to-pyruvate ratio detected by in vivo MRS imaging, whereas an increase in this ratio occurred with tumor growth in control animals. Taken together, our findings illustrate the application of hyperpolarized (13)C MRS of pyruvate to monitor alterations in LDHA activity and expression caused by PI3K pathway inhibition, showing the potential of this method for noninvasive imaging of drug target modulation.

Topics: Animals; Carbon Isotopes; Chromones; Drug Delivery Systems; Enzyme Inhibitors; Everolimus; Glioblastoma; Humans; Lactic Acid; Magnetic Resonance Spectroscopy; Mice; Mice, Nude; Monitoring, Physiologic; Morpholines; Neoplasms; Phosphoinositide-3 Kinase Inhibitors; Sirolimus; Treatment Outcome; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Topics: Antibiotics, Antineoplastic; Disease Progression; Disease-Free Survival; Fluorine Radioisotopes; Fluorodeoxyglucose F18; Humans; Intracellular Signaling Peptides and Proteins; Neoplasms; Positron-Emission Tomography; Protein Serine-Threonine Kinases; Radiopharmaceuticals; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Mammalian target of rapamycin (mTOR) is a serine/threonine kinase that regulates a variety of cellular functions such as growth, proliferation and autophagy. In a variety of cancer cells, overactivation of mTOR has been reported. In addition, mTOR inhibitors, such as rapamycin and its derivatives, are being evaluated in clinical trials as anticancer drugs. However, no active mutants of mTOR have been identified in human cancer. Here, we report that two different point mutations, S2215Y and R2505P, identified in human cancer genome database confer constitutive activation of mTOR signaling even under nutrient starvation conditions. S2215Y was identified in large intestine adenocarcinoma whereas R2505P was identified in renal cell carcinoma. mTOR complex 1 prepared from cells expressing the mutant mTOR after nutrient starvation still retains the activity to phosphorylate 4E-BP1 in vitro. The cells expressing the mTOR mutant show increased percentage of S-phase cells and exhibit resistance to cell size decrease by amino-acid starvation. The activated mutants are still sensitive to rapamycin. However, they show increased resistance to 1-butanol. Our study points to the idea that mTOR activating mutations can be identified in a wide range of human cancer.

Topics: 1-Butanol; cdc25 Phosphatases; Humans; Intracellular Signaling Peptides and Proteins; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Phosphorylation; Point Mutation; Protein Serine-Threonine Kinases; Proteins; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; Structure-Activity Relationship; TOR Serine-Threonine Kinases; Transcription Factors

PI3K activation is commonly observed in many human cancer cells. Survivin expression is elevated in cancer cells, and induced by some growth factors through PI3K activation. However, it is not clear whether PI3K activation is sufficient to induce survivin expression. To investigate the role of PI3K pathway in the regulation of survivin, we expressed an active form of PI3K, v-P3k in chicken embryonic fibroblast cells (CEF), and found that overexpression of PI3K-induced survivin mRNA expression. Forced expression of wild-type but not mutant tumor suppressor PTEN in CEF decreased survivin mRNA levels. PI3K regulates survivin expression through Akt activation. To further investigate downstream target of PI3K and Akt in regulating the expression of survivin mRNA, we found that PI3K and Akt-induced p70S6K1 activation and that overexpression of p70S6K1 alone was sufficient to induce survivin expression. The treatment of CEF cells by rapamycin decreased the survivin mRNA expression. This result demonstrated that p70S6K1 is an important target downstream of PI3K and Akt in regulating suvivin mRNA expression. The knockdown of survivin mRNA expression by its specific siRNA induced apoptosis of cancer cells when the cells were treated with LY294002 or taxol. Taken together, these results demonstrated that PI3K/Akt/p70S6K1 pathway is essential for regulating survivin mRNA expression.

Topics: Animals; Apoptosis; Cell Line, Tumor; Chick Embryo; Chromones; Enzyme Inhibitors; Gene Knockdown Techniques; Humans; Inhibitor of Apoptosis Proteins; Microtubule-Associated Proteins; Morpholines; Neoplasms; Paclitaxel; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6 Kinases, 70-kDa; RNA, Messenger; RNA, Small Interfering; Sirolimus; Survivin

Aging is associated with obesity and cancer. Calorie restriction both slows down aging and delays cancer. Evidence has emerged that the nutrient-sensing mammalian target of rapamycin (mTOR) pathway is involved in cellular and organismal aging. Here we show that the mTOR inhibitor rapamycin prevents age-related weight gain, decreases rate of aging, increases lifespan, and suppresses carcinogenesis in transgenic HER-2/neu cancer-prone mice. Rapamycin dramatically delayed tumor onset as well as decreased the number of tumors per animal and tumor size. We suggest that, by slowing down organismal aging, rapamycin delays cancer.

Topics: Adenocarcinoma; Animals; Female; Gene Expression Regulation, Neoplastic; Genetic Predisposition to Disease; Homozygote; Longevity; Mammary Neoplasms, Animal; Mice; Mice, Transgenic; Models, Theoretical; Neoplasms; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Insulin-like growth factor binding protein 2 (IGFBP-2) has been implicated in the pathophysiology of neoplasia. The PI3K/AKT/mTOR pathway has recently been shown to be a predominant regulator of IGFBP-2 at the protein level in MCF-7 breast cancer cells. However, there are gaps in knowledge with respect to the molecular mechanisms that underlie this regulation. Here, we show that the PI3K/AKT/mTOR pathway regulates IGFBP-2 protein levels by modulating IGFBP-2 mRNA abundance in MCF-7 cells. This change is achieved by regulating transcription through a critical region present in the first 200 bp upstream of the transcription initiation site where Sp1 transcription factor binds and drives transcription. IGF-1 treatment leads to increased nuclear abundance of Sp1 and increased IGFBP-2 mRNA and protein levels. Rapamycin and LY294002 induce a decline in Sp1 nuclear abundance and IGFBP-2 mRNA and protein levels. This work provides a mechanistic explanation for the observed effects of the PI3K/AKT/mTOR pathway on IGFBP-2 levels in MCF-7 cells.

Topics: Blotting, Western; Cell Line, Tumor; Chromones; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Gene Expression; Gene Expression Regulation; Humans; Insulin-Like Growth Factor Binding Protein 2; Intracellular Signaling Peptides and Proteins; Morpholines; Neoplasms; Phosphatidylinositol 3-Kinases; Polymerase Chain Reaction; Promoter Regions, Genetic; Protein Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; RNA, Messenger; Signal Transduction; Sirolimus; Somatomedins; Sp1 Transcription Factor; TOR Serine-Threonine Kinases; Transcription, Genetic

Numerous studies have shown that mammalian target of rapamycin (mTOR) inhibitor activates Akt signaling pathway via a negative feedback loop while inhibiting mTORC1 signaling. In this report, we focused on studying the role of mTORC1 and mTORC2 in rapamycin-mediated Akt and ERK phosphorylation, and the antitumor effect of rapamycin in cancer cells in combination with Akt and ERK inhibitors. Moreover, we analyzed the effect of mTORC1 and mTORC2 on regulating cell cycle progression. We found that low concentrations rapamycin increased Akt and ERK phosphorylation through a mTORC1-dependent mechanism because knockdowned raptor induced the activation of Akt and ERK, but higher doses of rapamycin inhibited Akt and ERK phosphorylation mainly via the mTORC2 signaling pathway because that the silencing of rictor led to the inhibition of Akt and ERK phosphorylation. We further showed that mTORC2 was tightly associated with the development of cell cycle through an Akt-dependent mechanism. Therefore, we combined PI3K and ERK inhibitors prevent rapamycin-induced Akt activation and enhanced antitumor effects of rapamycin. Collectively, we conclude that mTORC2 plays a much more important role than mTORC1 in rapamycin-mediated phosphorylation of Akt and ERK, and cotargeting AKT and ERK signaling may be a new strategy for enhancing the efficacy of rapamycin-based therapeutic approaches in cancer cells.

Topics: Antibiotics, Antineoplastic; Cell Line, Tumor; Extracellular Signal-Regulated MAP Kinases; Humans; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Phosphorylation; Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Malignancies are a well-known complication of immunosuppressive therapy among renal transplant recipients, representing an important cause of long-term morbidity and mortality. Rapamycin has been shown to limit the proliferation of a number of malignant cell lines in vivo and in vitro.. Fifteen patients developed the following malignancies at a mean of 90.3 months (range = 10-252) after kidney transplantation: metastatic gastric cancer (n = 1), metastatic colon cancer (n = 1), bilateral nephrourothelioma (n = 1), skin cancer (n = 2), Kaposi's sarcoma (n = 2), posttransplant lymphoproliferative disorder (PTLD; n = 4), renal cell carcinoma T1 (n = 1), MALT lymphoma (n = 1), intramucous colon carcinoma (n = 1), liposarcoma of the spermatic cord (n = 1). After the diagnosis of malignancy, the patients were switched from calcineurin inhibitor-based immunosuppression to rapamycin (monotherapy, n = 3), or associated with steroids (n = 6) or with mycophenolate mofetil (n = 6).. Both patients with metastatic cancer underwent chemotherapy but succumbed after 6 and 13 months. Two patients with PTLD who underwent chemotherapy died after 12 and 36 months. At a mean follow-up of 32.7 months (range = 7-56), the remaining 11 patients are cancer-free. Two patients lost their grafts after 24 and 36 months after the switch due to chronic rejection. Renal graft function remained stable in all other patients from diagnosis throughout follow-up.. Our observations suggested that rapamycin-based immunosuppression offers the possibility for regression of nonmetastatic tumors. Nevertheless, it is difficult to assess whether tumor regression was due to rapamycin treatment or to the reduced immunosuppression.

Topics: Cell Division; Cell Line, Tumor; Colonic Neoplasms; Genital Neoplasms, Male; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Kidney Transplantation; Liposarcoma; Male; Neoplasm Metastasis; Neoplasms; Sirolimus; Skin Neoplasms; Stomach Neoplasms

Lymphangiogenesis induced during tumor growth contributes to metastasis. Genetic and chemical screens using the zebrafish model have the potential to enhance our understanding of lymphangiogenesis, and lead to the discovery of pharmacological agents with activity in the lymphatic system. Large-scale screening of lymphatic development in the whole zebrafish embryo requires a specific lymphatic endothelial cell marker. We isolated the zebrafish ortholog of Lyve1, and analyzed its expression pattern during embryogenesis, and under conditions where key regulators of lymphangiogenesis such as Prox1 and VegfC were depleted. Like humans, zebrafish embryos form lymph sacs, lymphangioblasts arise from venous endothelia, and they form asymmetric left and right collecting ducts. By monitoring the earliest lymphatic sprouting in the head, a pilot drug assay was performed showing rapamycin, an inhibitor of mammalian lymphangiogenesis, can also suppress zebrafish lymphangiogenesis. This work opens up a novel opportunity to further the understanding of, and potentially manipulate, human lymphangiogenesis.

Topics: Animals; In Situ Hybridization; Lymphangiogenesis; Mice; Neoplasms; Sirolimus; Zebrafish; Zebrafish Proteins

Personalized cancer medicine is based on the concept that targeted therapies are effective on subsets of patients whose tumors carry specific molecular alterations. Several mammalian target of rapamycin (mTOR) inhibitors are in preclinical or clinical trials for cancers, but the molecular basis of sensitivity or resistance to these inhibitors among patients is largely unknown. Here we have identified oncogenic variants of phosphoinositide-3-kinase, catalytic, alpha polypeptide (PIK3CA) and KRAS as determinants of response to the mTOR inhibitor everolimus. Human cancer cells carrying alterations in the PI3K pathway were responsive to everolimus, both in vitro and in vivo, except when KRAS mutations occurred concomitantly or were exogenously introduced. In human cancer cells with mutations in both PIK3CA and KRAS, genetic ablation of mutant KRAS reinstated response to the drug. Consistent with these data, PIK3CA mutant cells, but not KRAS mutant cells, displayed everolimus-sensitive translation. Importantly, in a cohort of metastatic cancer patients, the presence of oncogenic KRAS mutations was associated with lack of benefit after everolimus therapy. Thus, our results demonstrate that alterations in the KRAS and PIK3CA genes may represent biomarkers to optimize treatment of patients with mTOR inhibitors.

Topics: Cell Line, Tumor; Class I Phosphatidylinositol 3-Kinases; Everolimus; Humans; Intracellular Signaling Peptides and Proteins; Mutation; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins p21(ras); ras Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Targeted cancer therapeutics can be effective when patients are preselected to maximize the chance of response. Increasingly, molecular markers such as oncogenic DNA mutations are being exploited to help guide patient preselection. These DNA lesions can predict for either a positive or negative response to a given drug. Finding such predictive biomarkers is an ongoing challenge. New work by Di Nicolantonio and colleagues in this issue of the JCI demonstrates that PI3K catalytic alpha subunit (PIK3CA) mutations can sensitize cancer cells to the mammalian target of rapamycin (mTOR) inhibitor everolimus. In addition, they show that the concurrent presence of PIK3CA mutations and mutations in either KRAS or BRAF predict for resistance to this drug. These data suggest that mTOR inhibitors currently in use will be ineffective against cancers that have a mutation in either KRAS or BRAF despite having PI3K/AKT/mTOR pathway activation.

Topics: Class I Phosphatidylinositol 3-Kinases; Everolimus; Humans; Intracellular Signaling Peptides and Proteins; Mutation; Neoplasms; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins B-raf; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins p21(ras); ras Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Topics: Angiogenesis Inhibitors; Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Capecitabine; Clinical Trials, Phase I as Topic; Deoxycytidine; Drug Administration Schedule; Drug Interactions; Evidence-Based Medicine; Fluorouracil; Humans; Intracellular Signaling Peptides and Proteins; Maximum Tolerated Dose; Neoplasms; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Humans; Mammals; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; Proteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Cetuximab is an epidermal growth factor receptor (EGFR)-blocking antibody that is approved to treat several types of solid cancers in patients. We recently showed that cetuximab can induce autophagy in cancer cells by both inhibiting the class I phosphatidylinositol 3-kinase (PtdIns3K)/Akt/mammalian target of rapamycin (mTOR) pathway and activating the class III PtdIns3K (hVps34)/beclin 1 pathway. In the current study, we investigated the relationship between cetuximab-induced autophagy and apoptosis and the biological roles of autophagy in cetuximab-mediated cancer therapy. We found that cetuximab induced autophagy in cancer cells that show strong or weak induction of apoptosis after cetuximab treatment but not in those that show only cytostatic growth inhibition. Inhibition of cetuximab-induced apoptosis by a caspase inhibitor prevented the induction of autophagy. Conversely, inhibition of cetuximab-induced autophagy by silencing the expression of autophagy-related genes (Atg) or treating the cancer cells with lysosomal inhibitors enhanced the cetuximab-induced apoptosis, suggesting that autophagy was a protective cellular response to cetuximab treatment. On the other hand, cotreatment of cancer cells with cetuximab and the mTOR inhibitor rapamycin resulted in an Atg-dependent and lysosomal inhibition-sensitive death of cancer cells that show only growth inhibition or weak apoptosis after cetuximab treatment, indicating that cell death may be achieved by activating the autophagy pathway in these cells. Together, our findings may guide the development of novel clinical strategies for sensitizing cancer cells to EGFR-targeted therapy.

Topics: Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Apoptosis; Autophagy; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cetuximab; Chloroquine; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; ErbB Receptors; Humans; Neoplasms; Phagosomes; Sirolimus

Autophagy is one of the survival processes of cancer cells, especially in stressful conditions such as starvation, hypoxia and chemotherapeutic agents. However, its roles in tumor survival have not yet been fully elucidated. Here, we found for the first time that JAK2/STAT3 was activated in HeLa cells when they were starved or treated with rapamycin. STAT3 activation was associated with autophagic processes, because it was completely inhibited by 3-methyladenine, partially inhibited by knockdown of molecules associated with autophagic processes and blocked by antioxidants, DPI, a Nox inhibitor and knockdown of p22 phox, indicating that ROS generated by Nox that was activated during autophagic processes activated JAK2/STAT3 pathway. Activated STAT3 directly bound to IL6 promoter and increased IL6 mRNA and protein secretion. Finally, the conditioned media, which included IL6, from starved HeLa cells promoted cancer cell survival in both normal and starved conditions, confirmed by clonogenic, proliferation and cell death assays. These data together indicate that the autophagic process in cancer cells can contribute to their survival by JAk2/STAT3 activation and subsequent secretion of growth factors.

Topics: Amino Acids; Autophagy; Base Sequence; Cell Proliferation; Cell Survival; Culture Media, Conditioned; Enzyme Activation; Gene Expression Regulation, Neoplastic; Glucose; HeLa Cells; Humans; Interleukin-6; Molecular Sequence Data; NADPH Oxidases; Neoplasms; Promoter Regions, Genetic; Protein Binding; Reactive Oxygen Species; Sirolimus; STAT3 Transcription Factor; Transcription, Genetic

Topics: Animals; Antineoplastic Agents; Apoptosis; bcl-X Protein; Drug Screening Assays, Antitumor; High-Throughput Screening Assays; Mice; Neoplasms; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Sirolimus

Autophagy, an evolutionally conserved intracellular process degrading cytoplasmic proteins and organelles for recycling, has become one of the most remarkable strategies applied in cancer research. The fullerene C60 nanoparticle (nC60) has been shown to induce autophagy and sensitize chemotherapeutic killing of cancer cells, but the details still remain unknown. Here we show that a water-dispersed nanoparticle solution of derivatized fullerene C60, C60(Nd) nanoparticles (nC60(Nd)), has greater potential in inducing autophagy and sensitizing chemotherapeutic killing of both normal and drug-resistant cancer cells than nC60 does in an autophagy-dependent fashion. Additionally we further demonstrated that autophagy induced by nC60/C60(Nd) and Rapamycin had completely different roles in cancer chemotherapy. Our results, for the first time, revealed a novel and more potent derivative of the C60 nanoparticle in enhancing the cytotoxicity of chemotherapeutic agents and reducing drug resistance through autophagy modulation, which may ultimately lead to novel therapeutic strategies in cancer therapy.

Topics: Animals; Autophagy; Cell Death; Cell Line, Transformed; Cisplatin; Doxorubicin; Drug Resistance, Neoplasm; Fullerenes; Green Fluorescent Proteins; HeLa Cells; Humans; Mice; Microtubule-Associated Proteins; Nanomedicine; Nanoparticles; Neoplasms; Reactive Oxygen Species; Sirolimus

The objectives of the present study were to evaluate the incidence of malignancies and to describe the effects of immunosuppression on survival and recurrence of malignancies after heart transplantation (HTX). Data were analyzed in 211 cardiac allograft recipients, in whom HTX was performed between 1989 and 2005. All of these patients survived for more than 2 years after HTX and received induction therapy with antithymocyte globulin (RATG) guided by T-cell monitoring since 1994. An immunosuppressive regimen consisting of cyclosporine A (CsA) combined with azathioprine was followed by CsA and mycophenolate mofetil (MMF) in 2001; mammalian target of rapamycin (mTOR) inhibitors (everolimus/sirolimus) were used since 2003. Mean patient age at HTX was 51.4 ± 10.5 years; mean follow-up time after HTX 9.2 ± 4.7 years. Overall incidence of neoplasias was 30.8%. Individual risk factors associated with a higher risk of malignancy after HTX were higher age at transplantation (P = .003), male gender (P = .005) and ischemic cardiomyopathy before HTX (P = .04). Administration of azathioprine (P < .0001) or a calcineurin inhibitor (CNI) (P = .02) for more than 1 year was associated with development of malignancy, whereas significantly fewer malignancies were noticed in patients receiving an mTOR-inhibitor (P < .0001). Kaplan-Meier analysis demonstrated a strong statistical trend toward an improved survival in patients with a noncutaneous neoplasia switched to a CNI-free protocol (P = .05). This study demonstrated the impact of a variety of individual risk factors and immunosuppressive drugs on development of malignancy after HTX. Markedly fewer patients with noncutaneous malignancies died after switch to a CNI-free regimen, not quite reaching statistical significance by Kaplan-Meier analysis, however.

Topics: Adolescent; Adult; Azathioprine; Calcineurin Inhibitors; Cyclosporine; Drug Therapy, Combination; Everolimus; Female; Germany; Heart Transplantation; Humans; Immunosuppressive Agents; Incidence; Kaplan-Meier Estimate; Male; Middle Aged; Mycophenolic Acid; Neoplasms; Proportional Hazards Models; Retrospective Studies; Risk Assessment; Risk Factors; Sirolimus; Skin Neoplasms; Survival Rate; Time Factors; TOR Serine-Threonine Kinases; Transplantation, Homologous; Treatment Outcome; Young Adult

When the cell cycle is arrested, growth-promoting pathways such as mTOR (Target of Rapamycin) drive cellular senescence, characterized by cellular hyper-activation, hypertrophy and permanent loss of the proliferative potential. While arresting cell cycle, p53 (under certain conditions) can inhibit the mTOR pathway. Senescence occurs when p53 fails to inhibit mTOR. Low concentrations of DNA-damaging drugs induce p53 at levels that do not inhibit mTOR, thus causing senescence. In quiescence caused by serum starvation, mTOR is deactivated. This predicts that induction of p53 will not cause senescence in such quiescent cells. Here we tested this prediction. In proliferating normal cells, etoposide caused senescence (cells could not resume proliferation after removal of etoposide). Serum starvation prevented induction of senescence, but not of p53, by etoposide. When etoposide was removed, such cells resumed proliferation upon addition of serum. Also, doxorubicin did not cause senescent morphology in the absence of serum. Re-addition of serum caused mTOR-dependent senescence in the presence of etoposide or doxorubicin. Also, serum-starvation prevented senescent morphology caused by nutlin-3a in MCF-7 and Mel-10 cells. We conclude that induction of p53 does not activate the senescence program in quiescent cells. In cells with induced p53, re-activation of mTOR by serum stimulation causes senescence, as an equivalent of cellular growth.

Topics: Cell Cycle; Cell Line; Cell Proliferation; Cell Shape; Cellular Senescence; DNA Damage; Doxorubicin; Enzyme Activation; Etoposide; Humans; Imidazoles; Neoplasms; Piperazines; Protein Kinase Inhibitors; Retinal Pigment Epithelium; Serum; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Tumor Suppressor Protein p53; Up-Regulation

Everolimus displays antiproliferative effects on cancer cells, yields antiangiogenic activity in established tumours, and shows synergistic activity with paclitaxel in preclinical models. This study assessed the safety and the pharmacokinetic interactions of everolimus and paclitaxel in patients with advanced malignancies. Everolimus was dose escalated from 15 to 30 mg and administered with paclitaxel 80 mg m(-2) on days 1, 8, and 15 every 28 days. Safety was assessed weekly, and dose-limiting toxicity (DLT) was evaluated in cycle 1. A total of 16 patients (median age 54.5 years, range 33-69) were entered; 11 had prior taxane therapy for breast (n=5), ovarian (n=3), and vaginal cancer (n=1) or angiosarcoma (n=2). Grade 3 neutropenia in six patients met the criteria for DLT in two patients receiving everolimus 30 mg weekly. Other drug-related grade 3 toxicities were leucopenia, anaemia, thrombocytopenia, stomatitis, asthenia, and increased liver enzymes. Tumour stabilisation reported in 11 patients exceeded 6 months in 2 patients with breast cancer. Everolimus showed an acceptable safety profile at the dose of 30 mg when combined with weekly paclitaxel 80 mg m(-2), warranting further clinical investigation.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Dose-Response Relationship, Drug; Drug Monitoring; Everolimus; Female; Humans; Middle Aged; Neoplasm Staging; Neoplasms; Paclitaxel; Prognosis; Protein Kinases; Sirolimus; Survival Rate; Tissue Distribution; TOR Serine-Threonine Kinases; Treatment Outcome

Since the late 1990s and the rapid expansion of monoclonal antibodies and synthetic protein kinase inhibitors in oncology, anticancer natural products fell out of fashion with the pharmaceutical industry. But in 2007 with the approval of three new drugs derived from natural products, the emergence of promising antitumor compounds from microorganisms (e.g. alvespimycin, salinosporamide) and the growing importance of new formulations of known natural product-derived drugs (nanoparticle formulations, oral forms), we are witnessing a new wave for natural products in oncology. The recent approval of the microtubule-targeted epothilone derivative ixabepilone (Ixempra), the DNA-alkylating marine alkaloid trabectedin (Yondelis) and the inhibitor of mTOR protein kinase temsirolimus (Torisel) is emblematic of the evolution of the field which combines the long established finding of conventional cytotoxic agents and the emergence of molecularly targeted therapeutics. These three examples also illustrate the increasing importance of microbial sources for the discovery of medically useful natural products. The contribution of innovative biological targets is also highlighted here, with references to proteasome inhibitors and novel approaches such as manipulation of mRNA splicing. Altogether, these observations plead for the return of natural products in oncology.

Topics: Antineoplastic Agents; Biological Products; Dioxoles; Epothilones; Humans; Neoplasms; Sirolimus; Tetrahydroisoquinolines; Trabectedin

Enhanced lysosomal trafficking is associated with metastatic cancer. In an attempt to discover cancer relevant lysosomal motor proteins, we compared the lysosomal proteomes from parental MCF-7 breast cancer cells with those from highly invasive MCF-7 cells that express an active form of the ErbB2 (DeltaN-ErbB2).. Mass spectrometry analysis identified kinesin heavy chain protein KIF5B as the only microtubule motor associated with the lysosomes in MCF-7 cells, and ectopic DeltaN-ErbB2 enhanced its lysosomal association. KIF5B associated with lysosomes also in HeLa cervix carcinoma cells as analyzed by subcellular fractionation. The depletion of KIF5B triggered peripheral aggregations of lysosomes followed by lysosomal destabilization, and cell death in HeLa cells. Lysosomal exocytosis in response to plasma membrane damage as well as fluid phase endocytosis functioned, however, normally in these cells. Both HeLa and MCF-7 cells appeared to express similar levels of the KIF5B isoform but the death phenotype was weaker in KIF5B-depleted MCF-7 cells. Surprisingly, KIF5B depletion inhibited the rapamycin-induced accumulation of autophagosomes in MCF-7 cells. In KIF5B-depleted cells the autophagosomes formed and accumulated in the close proximity to the Golgi apparatus, whereas in the control cells they appeared uniformly distributed in the cytoplasm.. Our data identify KIF5B as a cancer relevant lysosomal motor protein with additional functions in autophagosome formation.

Topics: Autophagy; Cell Death; Cell Line, Tumor; Humans; Kinesins; Lysosomes; Mass Spectrometry; Neoplasms; Organelles; Phagosomes; Protein Transport; Proteomics; Receptor, ErbB-2; Sirolimus

Mammalian target of rapamycin (mTOR) regulates cellular processes important for progression of human cancer. RAD001 (everolimus), an mTORC1 (mTOR/raptor) inhibitor, has broad antitumor activity in preclinical models and cancer patients. Although most tumor lines are RAD001 sensitive, some are not. Selective mTORC1 inhibition can elicit increased AKT S473 phosphorylation, involving insulin receptor substrate 1, which is suggested to potentially attenuate effects on tumor cell proliferation and viability. Rictor may also play a role because rictor kinase complexes (including mTOR/rictor) regulate AKT S473 phosphorylation. The role of raptor and rictor in the in vitro response of human cancer cells to RAD001 was investigated. Using a large panel of cell lines representing different tumor histotypes, the basal phosphorylation of AKT S473 and some AKT substrates was found to correlate with the antiproliferative response to RAD001. In contrast, increased AKT S473 phosphorylation induced by RAD001 did not correlate. Similar increases in AKT phosphorylation occurred following raptor depletion using siRNA. Strikingly, rictor down-regulation attenuated AKT S473 phosphorylation induced by mTORC1 inhibition. Further analyses showed no relationship between modulation of AKT phosphorylation on S473 and T308 and AKT substrate phosphorylation patterns. Using a dual pan-class I phosphatidylinositol 3-kinase/mTOR catalytic inhibitor (NVP-BEZ235), currently in phase I trials, concomitant targeting of these kinases inhibited AKT S473 phosphorylation, eliciting more profound cellular responses than mTORC1 inhibition alone. However, reduced cell viability could not be predicted from biochemical or cellular responses to mTORC1 inhibitors. These data could have implications for the clinical application of phosphatidylinositol 3-kinase/mTOR inhibitors.

Topics: Carrier Proteins; Cell Proliferation; Cell Survival; Everolimus; Humans; Imidazoles; Immunoblotting; Immunosuppressive Agents; Insulin Receptor Substrate Proteins; Mechanistic Target of Rapamycin Complex 1; Multiprotein Complexes; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinases; Proteins; Proto-Oncogene Proteins c-akt; Quinolines; Rapamycin-Insensitive Companion of mTOR Protein; RNA, Small Interfering; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tumor Cells, Cultured

Nowadays cancer represents the second main cause of death in renal transplant patients with normal function of the graft. The incidence is 10 to 20 times higher than normal population. Calcineurin inhibitor therapy contributes to the increase in the development of neoplasia. Important evidence could bring a preventive effect of mammalian target of rapamycin in skin cancer, Kaposi's sarcoma, and renal cell carcinoma.

Topics: Aged; Calcineurin Inhibitors; Carcinoma, Renal Cell; Cause of Death; Female; Humans; Immunosuppressive Agents; Kidney Neoplasms; Kidney Transplantation; Male; Middle Aged; Neoplasms; Postoperative Complications; Protein Kinases; Risk Factors; Sarcoma, Kaposi; Sirolimus; Skin Neoplasms; TOR Serine-Threonine Kinases

Small late-conversion studies found an impressive glomerular filtration rate (GFR) increase 1 year after conversion from calcineurin inhibitor (CNI) to sirolimus (SRL). This effect could not be detected in the considerably larger CONVERT study, which found a lower rate of malignancies in the SRL group. In the spare the nephron trial patients converted to SRL exhibited a mean measured GFR of 68 mL/min at 1 year compared with 60 mL/min from CNI patients (P<0.05). Accordingly, the CONCEPT study which randomized patients to SRL conversion 3 months after transplantation reported a significant higher GFR in the SRL patients at 1 year. These trials showed that conversion of stable renal transplant recipients from CNI to SRL is safe.

Topics: Biopsy; Calcineurin Inhibitors; Cyclosporine; Follow-Up Studies; Glomerular Filtration Rate; Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Randomized Controlled Trials as Topic; Safety; Sirolimus; Treatment Failure; Treatment Outcome

This study aimed to test whether [(18)F]fluoro-D-glucose (FDG) uptake of tumours measured by positron emission tomography (PET) can be used as surrogate marker to define the optimal biological dose (OBD) of mTOR inhibitors in vivo. Everolimus at 0.05, 0.5, 5 and 15 mg kg(-1) per day was administered to gastric cancer xenograft-bearing mice for 23 days and FDG uptake of tumours was measured using PET from day 1 to day 8. To provide standard comparators for FDG uptake, tumour volume, S6 protein phosphorylation, Ki-67 staining and everolimus blood levels were evaluated. Everolimus blood levels increased in a dose-dependent manner but antitumour activity of everolimus reached a plateau at doses >or=5 mg kg(-1) per day (tumour volume treated vs control (T/C): 51% for 5 mg kg(-1) per day and 57% for 15 mg kg(-1) per day). Correspondingly, doses >or=5 mg kg(-1) per day led to a significant reduction in FDG uptake of tumours. Dose escalation above 5 mg kg(-1) per day did not reduce FDG uptake any further (FDG uptake T/C: 49% for 5 mg kg(-1) per day and 52% for 15 mg kg(-1) per day). Differences in S6 protein phosphorylation and Ki-67 index reflected tumour volume and changes in FDG uptake but did not reach statistical significance. In conclusion, FDG uptake might serve as a surrogate marker for dose finding studies for mTOR inhibitors in (pre)clinical trials.

Topics: Animals; Antineoplastic Agents; Biomarkers; Carrier Proteins; Cell Line, Tumor; Enzyme Inhibitors; Everolimus; Female; Fluorodeoxyglucose F18; Humans; Mice; Mice, Nude; Neoplasms; Phosphotransferases (Alcohol Group Acceptor); Positron-Emission Tomography; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays

beclin 1, the mammalian homologue of the yeast Atg6, is a key autophagy-promoting gene that plays a critical role in the regulation of cell death and survival of various types of cells. However, recent studies have observed that the expression of beclin 1 is altered in certain diseases including cancers. The causes underlying the aberrant expression of beclin 1 remain largely unknown. We report here that microRNAs (miRNAs), a class of endogenous, 22-24 nucleotide noncoding RNA molecules able to affect stability and translation of mRNA, may represent a previously unrecognized mechanism for regulating beclin 1 expression and autophagy. We demonstrated that beclin 1 is a potential target for miRNA miR-30a, and this miRNA could negatively regulate beclin 1 expression resulting in decreased autophagic activity. Treatment of tumor cells with the miR-30a mimic decreased, and with the antagomir increased, the expression of beclin 1 mRNA and protein. Dual luciferase reporter assay confirmed that the miR-30a binding sequences in the 3'-UTR of beclin 1 contribute to the modulation of beclin 1 expression by miR-30a. Furthermore, inhibition of beclin 1 expression by the miR-30a mimic blunted activation of autophagy induced by rapamycin. Our study of the role of miR-30a in regulating beclin 1 expression and autophagy reveals a novel function for miRNA in a critical cellular event with significant impacts in cancer development, progression and treatment, and in other diseases.

Topics: Apoptosis Regulatory Proteins; Autophagy; Base Sequence; Beclin-1; Cell Line, Tumor; Consensus Sequence; Gene Expression Regulation, Neoplastic; Humans; Membrane Proteins; MicroRNAs; Molecular Sequence Data; Neoplasms; Oligonucleotide Array Sequence Analysis; Resveratrol; Sirolimus; Stilbenes; Vacuoles

Genome-wide copy number analyses of human cancers identified a frequent 5p13 amplification in several solid tumour types, including lung (56%), ovarian (38%), breast (32%), prostate (37%) and melanoma (32%). Here, using integrative analysis of a genomic profile of the region, we identify a Golgi protein, GOLPH3, as a candidate targeted for amplification. Gain- and loss-of-function studies in vitro and in vivo validated GOLPH3 as a potent oncogene. Physically, GOLPH3 localizes to the trans-Golgi network and interacts with components of the retromer complex, which in yeast has been linked to target of rapamycin (TOR) signalling. Mechanistically, GOLPH3 regulates cell size, enhances growth-factor-induced mTOR (also known as FRAP1) signalling in human cancer cells, and alters the response to an mTOR inhibitor in vivo. Thus, genomic and genetic, biological, functional and biochemical data in yeast and humans establishes GOLPH3 as a new oncogene that is commonly targeted for amplification in human cancer, and is capable of modulating the response to rapamycin, a cancer drug in clinical use.

Topics: Animals; Antibiotics, Antineoplastic; Cell Line, Tumor; DNA-Binding Proteins; Female; Gene Knockdown Techniques; Humans; Membrane Proteins; Mice; Mice, Nude; Neoplasms; Protein Kinases; Saccharomyces cerevisiae; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Topics: Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; CHO Cells; Cricetinae; Cricetulus; Drug Resistance, Neoplasm; Humans; Macrolides; Neoplasms; Sirolimus; Verapamil

Rapamycin, a potential anti-cancer agent, modulates activity of various factors functioning in translation, including eIF4E, an initiation factor selectively regulating expression of a subset of cellular transcripts. We show here that rapamycin suppresses levels of the p53-regulator MDM2 by translational inhibition without affecting mdm2 mRNA expression or protein stability. Rapamycin inhibits translation of mdm2 mRNA from the constitutive P1 promoter, which contains two upstream ORFs (uORFs) in the 5'UTR. Suppression is accompanied by increased hypo-phosphorylation of 4EBP-1, an inhibitory eIF4E binding protein. Ectopic expression of eIF4E abrogates rapamycin-mediated MDM2 inhibition, suggesting that eIF4E is crucial in modulating MDM2 expression in rapamycin-treated cells. Rapamycin administration also results in elevated PUMA expression and PARP cleavage, which is reproduced by siRNA knockdown of eIF4E or MDM2, suggesting that MDM2 suppression by rapamycin stimulates p53-mediated apoptosis. Together, our results define translational regulation of MDM2 expression by eIF4E and provide a molecular mechanism underlying rapamycin-induced p53-dependent apoptosis.

Topics: 5' Untranslated Regions; Antibiotics, Antineoplastic; Apoptosis; Blotting, Western; Cell Line, Tumor; Eukaryotic Initiation Factor-4E; Gene Expression Regulation, Neoplastic; HCT116 Cells; Humans; Neoplasms; Protein Biosynthesis; Proto-Oncogene Proteins c-mdm2; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Sirolimus; Tumor Suppressor Protein p53

Topics: Amino Acid Substitution; Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Membrane; Enzyme Activation; Humans; Mice; Mice, Nude; Mutation; Neoplasms; Protein Transport; Proto-Oncogene Proteins c-akt; RNA Interference; Signal Transduction; Sirolimus; TNF Receptor-Associated Factor 6; Ubiquitin-Protein Ligases; Ubiquitination

The underlying mechanism regulating the expression of the cancer stem cell/tumor-initiating cell marker CD133/prominin-1 in cancer cells remains largely unclear, although knowledge of this mechanism would likely provide important biological information regarding cancer stem cells. Here, we found that the inhibition of mTOR signaling up-regulated CD133 expression at both the mRNA and protein levels in a CD133-overexpressing cancer cell line. This effect was canceled by a rapamycin-competitor, tacrolimus, and was not modified by conventional cytotoxic drugs. We hypothesized that hypoxia-inducible factor-1 alpha (HIF-1 alpha), a downstream molecule in the mTOR signaling pathway, might regulate CD133 expression; we therefore investigated the relation between CD133 and HIF-1 alpha. Hypoxic conditions up-regulated HIF-1 alpha expression and inversely down-regulated CD133 expression at both the mRNA and protein levels. Similarly, the HIF-1 alpha activator deferoxamine mesylate dose-dependently down-regulated CD133 expression, consistent with the effects of hypoxic conditions. Finally, the correlations between CD133 and the expressions of HIF-1 alpha and HIF-1 beta were examined using clinical gastric cancer samples. A strong inverse correlation (r = -0.68) was observed between CD133 and HIF-1 alpha, but not between CD133 and HIF-1 beta. In conclusion, these results indicate that HIF-1 alpha down-regulates CD133 expression and suggest that mTOR signaling is involved in the expression of CD133 in cancer cells. Our findings provide a novel insight into the regulatory mechanisms of CD133 expression via mTOR signaling and HIF-1 alpha in cancer cells and might lead to insights into the involvement of the mTOR signal and oxygen-sensitive intracellular pathways in the maintenance of stemness in cancer stem cells.

Topics: AC133 Antigen; Antigens, CD; Cell Line, Tumor; Chromones; Colorectal Neoplasms; Down-Regulation; Glycoproteins; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Lung Neoplasms; Morpholines; Neoplasms; Peptides; Protein Kinases; RNA, Messenger; Signal Transduction; Sirolimus; Stomach Neoplasms; Tacrolimus; TOR Serine-Threonine Kinases; Transcription, Genetic; Up-Regulation

Malignancy is a dreaded complication following organ transplantation. Immunosuppressive therapy-induced impairment of the host immune system is the prevailing hypothesis for the high incidence and aggressive progression of post-transplant neoplasm. We summarize our observations supporting an autonomous cellular mechanism for cyclosporine and tacrolimus associated metastases. Cyclosporine conferred tumor invasiveness by a direct effect on the tumor cells and promoted metastases in T-, B-, and NK cell deficient SCID- beige mice, and anti-TGF-beta antibodies reduced metastases. Tacrolimus, another calcineurin inhibitor widely used in transplantation, induced TGF-beta secretion by tumor cells and promoted metastases in the SCID- beige mice. The immunosuppressive macrolide rapamycin reversed an invasive phenotype to a non-invasive one, reduced circulating levels of TGF-beta1 and prevented tumor growth and metastases in the immocompetant BALB/c mice and in the SCID-beige mice. Our studies, in addition to demonstrating a cell autonomous mechanism for tumor progression, advance TGF-beta blockade as an anti-tumor strategy.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Cell Line, Tumor; Cyclosporine; Humans; Immunosuppressive Agents; Kidney Neoplasms; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Inbred DBA; Mice, SCID; Neoplasm Invasiveness; Neoplasms; Organ Transplantation; Phenotype; Sirolimus; Tacrolimus

Sirolimus, a macrolide with immunosuppressive properties, was introduced into clinical practice a decade ago. The optimal use of this drug remains controversial: It displays a wide range of organ and tissue toxicities owing to the critical role of its therapeutic site- the kinase mammalian target of rapamycin-in the signal transduction pathways of numerous cytokines, growth factors, hormones, and nutrients. However, it displays unique, recognized benefits for renal transplant recipients: synergistic interactions with cyclosporine and possibly tacrolimus, allowing marked reduction in exposure to the calcineurin inhibitor; reduction in the frequency of posttransplant malignancies, particularly lymphomas, Kaposi sarcomas, and hypernephromas; and modest nephrotoxicity in comparison with calcineurin inhibitors. Because of its inhibitory effects on endothelial and smooth muscle cell proliferation, sirolimus may be a useful tool to dampen chronic vasculo-obliterative processes that attenuate graft survival. With increasing experience with the drug, the true potential of sirolimus will be realized to be a critical element in the immunosuppressive matrix.

Topics: Calcineurin Inhibitors; Drug Therapy, Combination; Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Postoperative Complications; Sirolimus; Tacrolimus

Topics: Antineoplastic Agents; Clinical Trials as Topic; Disease Progression; Humans; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

SIMCA classification can be applied to 2D-PAGE maps to identify changes occurring in cellular protein contents as a consequence of illnesses or therapies. These data sets are complex to treat due to the large number of proteins detected. A method for identifying relevant proteins from SIMCA discriminating powers is proposed, based on the Box-Cox transformation coupled to probability papers. The method successfully allowed the identification of the relevant spots from 2D maps.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Electrophoresis, Gel, Two-Dimensional; Endothelium; Humans; Hydroxamic Acids; Mice; Neoplasms; Neuroblastoma; Pancreas; Pancreatic Neoplasms; Probability; Proteins; Proteomics; Sirolimus; Statistical Distributions; Vinblastine

Gain-of-function alterations to the sonic hedgehog (SHH) signaling cascade have been found in a wide range of tumors. Three SHH effectors, GLI1, GLI2, and GLI3, regulate transcription of diverse genes involved in cell growth and cell proliferation. Here, we show that protein phosphatase 2A (PP2A), its regulatory subunit, alpha4, and rapamycin, an inhibitor of the mammalian target of rapamycin kinase complex 1 (mTORC1), regulate the nuclear localization and transcriptional activity of GLI3. An increase in PP2A activity or treatment with rapamycin leads to cytosolic retention of GLI3 and, consequently, reduced transcription of the GLI3 target gene and cell cycle regulator, cyclin D1. Conversely, inhibition of PP2A results in increased expression of cyclin D1. In summary, our findings reveal the existence of a hitherto unrecognized molecular cross-talk between the oncogenic SHH pathway and the tumor suppressor PP2A and suggest a novel mechanism underlying the anticancerogenic effects of rapamycin.

Topics: Adaptor Proteins, Signal Transducing; Cell Nucleus; Cyclin D; Cyclins; Cytosol; Fluorescent Antibody Technique; Green Fluorescent Proteins; Hedgehog Proteins; Humans; Immunosuppressive Agents; Intracellular Signaling Peptides and Proteins; Kruppel-Like Transcription Factors; Mechanistic Target of Rapamycin Complex 1; Molecular Chaperones; Multiprotein Complexes; Neoplasms; Nerve Tissue Proteins; Nuclear Proteins; Protein Phosphatase 2; Protein Transport; Proteins; Receptors, G-Protein-Coupled; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Sirolimus; Subcellular Fractions; TOR Serine-Threonine Kinases; Transcription Factors; Transcription, Genetic; Tumor Cells, Cultured; Zinc Finger Protein GLI1; Zinc Finger Protein Gli2; Zinc Finger Protein Gli3

Numerous studies have established a causal link between aberrant mammalian target of rapamycin (mTOR) activation and tumorigenesis, indicating that mTOR inhibition may have therapeutic potential. In this study, we show that rapamycin and its analogs activate the MAPK pathway in human cancer, in what represents a novel mTORC1-MAPK feedback loop. We found that tumor samples from patients with biopsy-accessible solid tumors of advanced disease treated with RAD001, a rapamycin derivative, showed an administration schedule-dependent increase in activation of the MAPK pathway. RAD001 treatment also led to MAPK activation in a mouse model of prostate cancer. We further show that rapamycin-induced MAPK activation occurs in both normal cells and cancer cells lines and that this feedback loop depends on an S6K-PI3K-Ras pathway. Significantly, pharmacological inhibition of the MAPK pathway enhanced the antitumoral effect of mTORC1 inhibition by rapamycin in cancer cells in vitro and in a xenograft mouse model. Taken together, our findings identify MAPK activation as a consequence of mTORC1 inhibition and underscore the potential of a combined therapeutic approach with mTORC1 and MAPK inhibitors, currently employed as single agents in the clinic, for the treatment of human cancers.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Enzyme Activation; Enzyme Inhibitors; Everolimus; Feedback, Physiological; Gene Expression Regulation, Neoplastic; Humans; Immunosuppressive Agents; MAP Kinase Signaling System; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Neoplasms; Proteins; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

The mammalian target of rapamycin (mTOR) has emerged as an important cancer therapeutic target. Several mTOR inhibitors are currently being tested in cancer clinical trials. Both PI3K/Akt and MEK/ERK signaling regulate mTOR axis. However, inhibition of mTOR activates Akt survival signaling, which in turn attenuates mTOR inhibitors' anticancer efficacy. We are interested in developing strategies for enhancing mTOR-targeted cancer therapy. In this study, we report that mTOR inhibition also induced activations of the MEK/ERK signaling pathway in some cancer cell lines after a prolonged treatment. The combination of rapamycin with the MEK inhibitor U0126 significantly enhanced growth inhibitory effects of cancer cells, suggesting that MEK/ERK activation may counteract mTOR inhibitors' anticancer efficacy. Similarly, the combination of an mTOR inhibitor with the EGF receptor inhibitor erlotinib synergistically inhibited the growth of both human cancer cells in cell cultures and xenografts in nude mice. Moreover, the presence of erlotinib suppressed rapamycin-induced phosphorylation of Akt, ERK and eIF4E as well, implying that erlotinib can suppress mTOR inhibition-induced feedback activation of several survival signaling pathways including Akt, ERK and eIF4E. Thus, we suggest a therapeutic strategy for enhancing mTOR-targeted cancer therapy by preventing mTOR inhibition-induced feedback activation of several survival mechanisms.

Topics: Antibiotics, Antineoplastic; Antineoplastic Agents; Carcinoma, Renal Cell; Cell Line, Tumor; Cell Survival; Enzyme Inhibitors; Erlotinib Hydrochloride; Extracellular Signal-Regulated MAP Kinases; Humans; Kidney Neoplasms; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Quinazolines; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

We have examined CD40-dependent signals in endothelial cells (EC) mediating the expression of vascular endothelial growth factor (VEGF) and VEGF-induced angiogenesis. We treated confluent cultures of EC with soluble CD40L (sCD40L), and by Western blot found a marked increase in the phosphorylation of Akt, 4EBP-1, and S6K1, compared with untreated cells. EC were transfected with a full-length VEGF promoter-luciferase construct and cultured in the absence or presence of rapamycin and sCD40L. We found that rapamycin, which blocks mTORC1 and mTORC2 signaling, inhibited sCD40L-mediated transactivation of VEGF. In addition, by Western blot, we found that the transfection of EC with small interfering RNA (siRNA) to rictor (to inhibit mTORC2), and not raptor (to inhibit mTORC1), inhibited sCD40L-dependent protein expression of VEGF. In additions, we found that basal levels of phosphorylated Akt as well as VEGF were increased in EC transfected with the raptor siRNA. Also, rapamycin failed to inhibit VEGF promoter activation, as well as VEGF protein expression in EC transfected with a constitutively active construct of Akt, further demonstrating that mTORC1 is not necessary for CD40- and Akt-induced expression of VEGF. Finally, we injected human CD40L-transfected fibroblasts or mock transfectants into human skin on SCID mice. We found that the injection of CD40L transfectants, but not mock cells, resulted in VEGF expression and mediated a marked angiogenesis reaction, and this response was reduced in mice treated with rapamycin. Together, these observations indicate that mTORC2 and Akt facilitate CD40-inducible expression of VEGF in EC, which is of clinical importance in tumor growth and the progression of chronic inflammatory diseases.

Topics: Adaptor Proteins, Signal Transducing; Animals; Anti-Bacterial Agents; Carrier Proteins; CD40 Antigens; CD40 Ligand; Cell Cycle Proteins; Endothelial Cells; Fibroblasts; Humans; Inflammation; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, SCID; Multiprotein Complexes; Neoplasms; Phosphoproteins; Phosphorylation; Promoter Regions, Genetic; Protein Biosynthesis; Proteins; Proto-Oncogene Proteins c-akt; Rapamycin-Insensitive Companion of mTOR Protein; Regulatory-Associated Protein of mTOR; Ribosomal Protein S6 Kinases; RNA, Small Interfering; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Transcriptional Activation; Vascular Endothelial Growth Factor A

Akt deficiency causes resistance to replicative senescence, to oxidative stress- and oncogenic Ras-induced premature senescence, and to reactive oxygen species (ROS)-mediated apoptosis. Akt activation induces premature senescence and sensitizes cells to ROS-mediated apoptosis by increasing intracellular ROS through increased oxygen consumption and by inhibiting the expression of ROS scavengers downstream of FoxO, particularly sestrin 3. This uncovers an Achilles' heel of Akt, since in contrast to its ability to inhibit apoptosis induced by multiple apoptotic stimuli, Akt could not inhibit ROS-mediated apoptosis. Furthermore, treatment with rapamycin that led to further Akt activation and resistance to etoposide hypersensitized cancer cells to ROS-mediated apoptosis. Given that rapamycin alone is mainly cytostatic, this constitutes a strategy for cancer therapy that selectively eradicates cancer cells via Akt activation.

Topics: Animals; Apoptosis; Cellular Senescence; Forkhead Box Protein O1; Forkhead Transcription Factors; Gene Expression Regulation, Neoplastic; Male; Mice; Mice, Knockout; Neoplasms; Oxidative Stress; Oxygen Consumption; Reactive Oxygen Species; RNA, Messenger; Signal Transduction; Sirolimus

Recent improvements in immunosuppressive therapies have reduced the incidence of acute rejection and increased patient survival. These agents may however contribute to higher rates of mortality due to an increased risk of cardiovascular disease or malignancy. Transplant patients are immunocompromised with a reduced ability to combat the development of malignancy. The higher risk for the activity of oncoviruses may also contribute to the higher incidence and determine specific tumor types. Some immunosuppressants seem to have direct oncogenic effects. In vitro data have demonstrated that calcineurin inhibitors (CNIs) may show direct effects on tumor growth and the development of metastases. In contrast, mTOR inhibitors have demonstrated anti-tumoral properties in vitro and perhaps potent anti-angiogenic effects thereby. Recent studies and registry analyses have confirmed that mTOR inhibitors are associated with a reduced incidence of malignancies. UNOS data demonstrated that an mTOR inhibitor, with or without a CNI, is associated with a reduced incidence of tumors compared to regimens without mTOR inhibitors. The Rapamune Maintenance Regimen study demonstrated that patients receiving sirolimus-based, CNI-free therapy after CsA withdrawal at 3 months showed a reduced incidence of malignancy at 5 years posttransplant, compared with those who continued on a regimen that included CsA. In the CONVERT study, patients converted to sirolimus revealed a significantly lower malignancy rate at 24 months (3.1%) compared with those who continued CNI-based therapy (9.8%, P < .001). The elimination of CNIs and the introduction of sirolimus may, therefore, have a role to reduce the risk of cancer among posttransplant patients.

Topics: Calcineurin Inhibitors; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Incidence; Neoplasms; Retroviridae; Sirolimus; Skin Neoplasms; Transplantation Immunology

Inactivating mutations in NF1 underlie the prevalent familial cancer syndrome neurofibromatosis type 1 [1]. The NF1-encoded protein is a Ras GTPase-activating protein (RasGAP) [2]. Accordingly, Ras is aberrantly activated in NF1-deficient tumors; however, it is unknown which effector pathways critically function in tumor development. Here we provide in vivo evidence that TORC1/mTOR activity is essential for tumorigenesis. Specifically, we show that the mTOR inhibitor rapamycin potently suppresses the growth of aggressive NF1-associated malignancies in a genetically engineered murine model. However, in these tumors rapamycin does not function via mechanisms generally assumed to mediate tumor suppression, including inhibition of HIF-1alpha and indirect suppression of AKT, but does suppress the mTOR target Cyclin D1 [3]. These results demonstrate that mTOR inhibitors may be an effective targeted therapy for this commonly untreatable malignancy. Moreover, they indicate that mTOR inhibitors do not suppress all tumor types via the same mechanism, suggesting that current biomarkers that rely on HIF-1alpha suppression may not be informative for all cancers. Finally, our results reveal important differences between the effects of mTOR inhibition on the microvasculature in genetically engineered versus xenograft models and indicate that the former may be required for effective preclinical screening with this class of inhibitors.

Topics: Animals; Cell Line; Cyclin D; Cyclins; Disease Models, Animal; Gene Expression Regulation; Genes, Neurofibromatosis 1; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neoplasms; Protein Kinase Inhibitors; Protein Kinases; Proto-Oncogene Proteins c-akt; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Topics: Antineoplastic Agents; Humans; Neoplasms; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Inhibition of a single transduction pathway is often inefficient due to activation of alternative signalling. The mammalian target of rapamycin (mTOR) is a key intracellular kinase integrating proliferation, survival and angiogenic pathways and has been implicated in the resistance to EGFR inhibitors. Thus, mTOR blockade is pursued to interfere at multiple levels with tumour growth. We used everolimus (RAD001) to inhibit mTOR, alone or in combination with anti-EGFR drugs gefitinib or cetuximab, on human cancer cell lines sensitive and resistant to EGFR inhibitors, both in vitro and in vivo. We demonstrated that everolimus is active against EGFR-resistant cancer cell lines and partially restores the ability of EGFR inhibitors to inhibit growth and survival. Everolimus reduces the expression of EGFR-related signalling effectors and VEGF production, inhibiting proliferation and capillary tube formation of endothelial cells, both alone and in combination with gefitinib. Finally, combination of everolimus and gefitinib inhibits growth of GEO and GEO-GR (gefitinib resistant) colon cancer xenografts, activation of signalling proteins and VEGF secretion. Targeting mTOR pathway with everolimus overcomes resistance to EGFR inhibitors and produces a cooperative effect with EGFR inhibitors, providing a valid therapeutic strategy to be tested in a clinical setting.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Cell Line, Tumor; Cetuximab; Drug Resistance, Neoplasm; Endothelial Cells; ErbB Receptors; Everolimus; Gefitinib; Humans; Mice; Mice, Inbred BALB C; Neoplasm Transplantation; Neoplasms; Neovascularization, Physiologic; Protein Kinases; Quinazolines; Sirolimus; TOR Serine-Threonine Kinases; Transplantation, Heterologous

Mammalian target of rapamycin, mTOR, is a major sensor of nutrient and energy availability in the cell and regulates a variety of cellular processes, including growth, proliferation, and metabolism. Loss of the tuberous sclerosis complex genes (TSC1 or TSC2) leads to constitutive activation of mTOR and downstream signaling elements, resulting in the development of tumors, neurological disorders, and at the cellular level, severe insulin/IGF-1 resistance. Here, we show that loss of TSC1 or TSC2 in cell lines and mouse or human tumors causes endoplasmic reticulum (ER) stress and activates the unfolded protein response (UPR). The resulting ER stress plays a significant role in the mTOR-mediated negative-feedback inhibition of insulin action and increases the vulnerability to apoptosis. These results demonstrate ER stress as a critical component of the pathologies associated with dysregulated mTOR activity and offer the possibility to exploit this mechanism for new therapeutic opportunities.

Topics: Adaptor Proteins, Signal Transducing; Animals; Antineoplastic Agents; Apoptosis; Cell Line; Child, Preschool; eIF-2 Kinase; Endoplasmic Reticulum; Genes, Tumor Suppressor; Humans; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred C57BL; Mice, Knockout; Multiprotein Complexes; Neoplasms; Neurons; Oxidative Stress; Phenylbutyrates; Proteins; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

Little is known about the signals downstream of PI3K which regulate mast cell homeostasis and function following FcepsilonRI aggregation and Kit ligation. In this study, we investigated the role of the mammalian target of rapamycin complex 1 (mTORC1) pathway in these responses. In human and mouse mast cells, stimulation via FcepsilonRI or Kit resulted in a marked PI3K-dependent activation of the mTORC1 pathway, as revealed by the wortmannin-sensitive sequential phosphorylation of tuberin, mTOR, p70S6 kinase (p70S6K), and 4E-BP1. In contrast, in human tumor mast cells, the mTORC1 pathway was constitutively activated and this was associated with markedly elevated levels of mTORC1 pathway components. Rapamycin, a specific inhibitor of mTORC1, selectively and completely blocked the FcepsilonRI- and Kit-induced mTORC1-dependent p70S6K phosphorylation and partially blocked the 4E-BP1 phosphorylation. In parallel, although rapamycin had no effect on FcepsilonRI-mediated degranulation or Kit-mediated cell adhesion, it inhibited cytokine production, and kit-mediated chemotaxis and cell survival. Furthermore, Rapamycin also blocked the constitutive activation of the mTORC1 pathway and inhibited cell survival of tumor mast cells. These data provide evidence that mTORC1 is a point of divergency for the PI3K-regulated downstream events of FcepsilonRI and Kit for the selective regulation of mast cell functions. Specifically, the mTORC1 pathway may play a critical role in normal and dysregulated control of mast cell homeostasis.

Topics: Animals; Cell Survival; Cells, Cultured; Humans; Kinetics; Mast Cells; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Neoplasms; Phosphatidylinositol 3-Kinases; Proteins; Proto-Oncogene Proteins c-kit; Receptors, IgE; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors

Myxoma virus is a rabbit-specific poxvirus pathogen that also exhibits a unique tropism for human tumor cells and is dramatically oncolytic for human cancer xenografts. Most tumor cell lines tested are permissive for myxoma infection in a fashion intimately tied to the activation state of Akt kinase. A host range factor of myxoma virus, M-T5, directly interacts with Akt and mediates myxoma virus tumor cell tropism. mTOR is a regulator of cell growth and metabolism downstream of Akt and is specifically inhibited by rapamycin. We report that treatment of nonpermissive human tumor cell lines, which normally restrict myxoma virus replication, with rapamycin dramatically increased virus tropism and spread in vitro. This increased myxoma replication is concomitant with global effects on mTOR signaling, specifically, an increase in Akt kinase. In contrast to the effects on human cancer cells, rapamycin does not increase myxoma virus replication in rabbit cell lines or permissive human tumor cell lines with constitutively active Akt. This indicates that rapamycin increases the oncolytic capacity of myxoma virus for human cancer cells by reconfiguring the internal cell signaling environment to one that is optimal for productive virus replication and suggests the possibility of a potentially therapeutic synergism between kinase signaling inhibitors and oncolytic poxviruses for cancer treatment.

Topics: Cell Line, Tumor; Humans; Myxoma virus; Neoplasms; Oncolytic Virotherapy; Oncolytic Viruses; Sirolimus; Viral Proteins

Regulated gene expression may be required for the clinical development of certain gene therapies. Several approaches have been developed that allow pharmacologic control of transgene expression, including the dimerizer-regulated transcriptional system in which rapamycin or its analogs function as transcriptional inducers. These compounds can also act as direct antitumor agents via inhibition of mammalian target of rapamycin (mTOR). We describe the development of an optimized recombinant adeno-associated virus (AAV) expression cassette that allows dimerizer-regulated gene expression from a single vector in vitro and in vivo. After demonstrating multiple cycles of rapamycin-dependent transgene induction following a single administration of an AAV vector in vivo, application of this regulated AAV gene expression system to the pharmacologic control of antiangiogenic therapy was evaluated in preclinical tumor models. Dimerizer-regulated vectors were constructed encoding a soluble inhibitor of the vascular endothelial growth factor (VEGF) pathway. In two subcutaneous models of glioblastoma, regulated expression of the VEGF inhibitor via recombinant AAV-mediated gene transfer, in combination with rapamycin, was shown to decrease tumor growth rate significantly. The dual properties of rapamycin--as a transcriptional inducer and mTOR inhibitor--are exploited in combination with an AAV-encoded antiangiogenic agent to provide a novel approach for the treatment of malignant diseases.

Topics: Angiostatins; Animals; Blotting, Western; Cell Line; Cell Line, Tumor; Dependovirus; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Gene Expression Regulation; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Glioblastoma; Humans; Immunosuppressive Agents; Mice; Mice, Nude; Neoplasms; Prealbumin; Promoter Regions, Genetic; Receptors, Vascular Endothelial Growth Factor; Sirolimus; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

Topics: Angiogenesis Inhibitors; Cyclosporine; Humans; Immunosuppressive Agents; Neoplasms; Organ Transplantation; Sarcoma, Kaposi; Sirolimus; Tacrolimus; United States

Although bystin has been identified as a protein potentially involved in embryo implantation (a process unique to mammals) in humans, the bystin gene is evolutionarily conserved from yeast to humans. DNA microarray data indicates that bystin is overexpressed in human cancers, suggesting that it promotes cell growth. We undertook RT (reverse transcription)-PCR and immunoblotting, and confirmed that bystin mRNA and protein respectively are expressed in human cancer cell lines, including HeLa. Subcellular fractionation identified bystin protein as nuclear and cytoplasmic, and immunofluorescence showed that nuclear bystin localizes mainly in the nucleolus. Sucrose gradient ultracentrifugation of total cytoplasmic ribosomes revealed preferential association of bystin with the 40S subunit fractions. To analyse its function, bystin expression in cells was suppressed by RNAi (RNA interference). Pulse-chase analysis of ribosomal RNA processing suggested that bystin knockdown delays processing of 18S ribosomal RNA, a component of the 40S subunit. Furthermore, this knockdown significantly inhibited cell proliferation. Our findings suggest that bystin may promote cell proliferation by facilitating ribosome biogenesis, specifically in the production of the 40S subunit. Localization of bystin to the nucleolus, the site of ribosome biogenesis, was blocked by low concentrations of actinomycin D, a reagent that causes nucleolar stress. When bystin was transiently overexpressed in HeLa cells subjected to nucleolar stress, nuclear bystin was included in particles different from the nuclear stress granules induced by heat shock. In contrast, cytoplasmic bystin was barely affected by nucleolar stress. These results suggest that, while bystin may play multiple roles in mammalian cells, a conserved function is to facilitate ribosome biogenesis required for cell growth.

Topics: Animals; Antibiotics, Antineoplastic; Cell Adhesion Molecules; Cell Line, Tumor; Cell Nucleolus; Cell Proliferation; Cytoplasm; DNA Damage; Humans; Neoplasms; Polyribosomes; Protein Kinases; Protein Subunits; Ribosomes; RNA Interference; RNA, Ribosomal, 18S; Sirolimus; Subcellular Fractions; TOR Serine-Threonine Kinases

The central role of phosphatidylinositol 3-kinase (PI3K, p110alpha) signaling in allowing cancer cells to bypass normal growth-limiting controls has led to the development of PI3K(p110alpha) inhibitors. A challenge in targeting PI3K(p110alpha) relates to the diverse actions of the PI3K pathway in numerous cell types. Recent findings in mice deficient in PI3K(p110alpha) activity in the heart, demonstrate the critical role of this pathway in protecting the heart against pathological insults. Mice deficient in PI3K(p110alpha) displayed accelerated heart failure in response to dilated or hypertrophic cardiomyopathy. These results help explain the association of cardiomyopathy in cancer patients given tyrosine kinase inhibitors and raise concerns for the use of PI3K(p110alpha) inhibitors in cancer patients with cardiovascular risk factors. Interestingly, an inhibitor of the mammalian target of rapamycin (a downstream effector of PI3K), did not have adverse effects on the heart. A more complete understanding of the complex arms and interactions of the PI3K pathway will hopefully lead to the development of anti-cancer agents without cardiac complications.

Topics: Animals; Antineoplastic Agents; Class I Phosphatidylinositol 3-Kinases; Enzyme Inhibitors; Heart; Heart Diseases; Humans; Mice; Mice, Transgenic; Models, Biological; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Sirolimus (SRL) has been proposed to replace calcineurin inhibitors (CNI) in case of CNI-induced toxicity. The aim of this study was to evaluate the efficacy and safety of conversion from CNI to SRL in maintenance liver transplantation (LT) patients. Between 2002 and 2006, conversion was performed in 48 patients (17 female, 31 male; mean age 57 +/- 10 yr) after a median delay of 19.4 months (range 0.2-173 months) after LT. Indication for conversion was renal impairment (RI) (78%), CNI neurotoxicity (13%), or post-LT cancer (9%). Median follow-up was 22.6 +/- 11 months. Median SRL dosage and trough levels were 2.4 +/- 1.3 mg and 8.1 +/- 2.7 microg/L. Immunosuppression consisted of SRL alone (33%), or SRL + mycophenolate mofetil (MMF) (39%), SRL + prednisone (15%), SRL + CNI (4%), or SRL + MMF + prednisone (8%). Mean glomerular filtration rate (GFR) improved from 33 to 48 mL/minute in patients with severe RI (P = 0.022) and from 56 to 74 mL/minute in patients with moderate RI (P = 0.0001). After conversion, main complications were albuminuria (36%), hyperlipidemia (49%), dermatitis (14%), edema (14%), oral ulcers (12%), joint pain (4%), infection (2%), and pneumonia (2%). Acute rejection (AR) occurred in 17% of the patients. SRL was withdrawn in 17% of the patients. In conclusion, conversion from CNI to SRL is safe and is associated with significant renal function improvement.

Topics: Aged; Calcineurin Inhibitors; Feasibility Studies; Female; Follow-Up Studies; Glomerular Filtration Rate; Humans; Immunosuppressive Agents; Kidney; Liver Transplantation; Male; Middle Aged; Neoplasms; Nervous System Diseases; Postoperative Care; Retreatment; Sirolimus; Treatment Outcome

Rapamycin, part of the immunosuppressive regimen of the Edmonton protocol, has been shown to inhibit vascular endothelial growth factor (VEGF) production and VEGF-mediated survival signalling in tumour cell lines. This study investigates the survival-promoting activities of VEGF in human islets and the effects of rapamycin on islet viability.. Levels of VEGF and its receptors in isolated human islets and whole pancreas was determined by western blotting and immunostaining. Islet viability following VEGF or immunosuppressive drug treatment was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Islet VEGF release was measured by ELISA. Mouse islets infected with an adenovirus expressing the gene for VEGF were transplanted syngeneically into streptozotocin-induced diabetic mice, with blood glucose levels measured three times per week.. Isolated human islets produced multiple isoforms of VEGF and VEGF receptors 1, 2 and 3 and the coreceptor neuropilin 1. Exogenous VEGF (10 ng/ml) prevented human islet death induced by serum starvation, which suggests that VEGF can act as a survival factor for human islets. Transplantation of mouse islets infected with a VEGF-expressing adenovirus in a syngeneic model, improved glycaemic control at day 1 post-transplantation (p < 0.05). Rapamycin at 10 and 100 ng/ml significantly reduced islet VEGF release (by 37 +/- 4% and 43 +/- 6%, respectively; p < 0.05) and at 100 ng/ml reduced islet viability (by 36 +/- 9%) and insulin release (by 47 +/- 7%, all vs vehicle-treated controls; p < 0.05). Tacrolimus had no effect on islet VEGF release or viability.. Our data suggest that rapamycin may have deleterious effects on islet survival post-transplantation, both through a direct effect on islet viability and indirectly through blockade of VEGF-mediated revascularisation.

Topics: Animals; Cell Survival; Cells, Cultured; Humans; Immunosuppressive Agents; Islets of Langerhans; Islets of Langerhans Transplantation; Mice; Mice, Inbred C57BL; Neoplasms; Neovascularization, Pathologic; Receptors, Vascular Endothelial Growth Factor; Signal Transduction; Sirolimus; Vascular Endothelial Growth Factor A

Tumors that form as a result of heightened mammalian target of rapamycin (mTOR) signaling are highly vascularized. This process of angiogenesis is regulated through hypoxia-inducible factor (HIF)-mediated transcription of angiogenic factors. It is recognized that inhibition of mTOR with rapamycin can diminish the process of angiogenesis. Our work shows that activation of mTOR by Ras homologue enriched in brain (Rheb) overexpression potently enhances the activity of HIF1alpha and vascular endothelial growth factor (VEGF)-A secretion during hypoxia, which is reversed with rapamycin. Mutants of Rheb, which do not bind guanine nucleotide (D60K, D60V, N119I, and D122N) and are unable to activate mTOR, inhibit the activity of HIF when overexpressed. We show that regulatory associated protein of mTOR (Raptor) interacts with HIF1alpha and requires an mTOR signaling (TOS) motif located in the N terminus of HIF1alpha. Furthermore, a mutant of HIF1alpha lacking this TOS motif dominantly impaired HIF activity during hypoxia and was unable to bind to the co-activator CBP/p300. Rapamycin treatments do not affect the stability of HIF1alpha and modulate HIF activity via a Von Hippel-Lindau (VHL)-independent mechanism. We demonstrate that the high levels of HIF activity in cells devoid of TSC2 can be reversed by treatments with rapamycin or the readdition of TSC2. Our work explains why human cancers with aberrant mTOR signaling are prone to angiogenesis and suggests that inhibition of mTOR with rapamycin might be a suitable therapeutic strategy.

Topics: Amino Acid Motifs; Animals; Antibiotics, Antineoplastic; Cell Hypoxia; Cell Line, Tumor; Guanine Nucleotides; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Monomeric GTP-Binding Proteins; Mutation, Missense; Neoplasms; Neovascularization, Pathologic; Neuropeptides; p300-CBP Transcription Factors; Protein Binding; Protein Kinases; Protein Structure, Tertiary; Ras Homolog Enriched in Brain Protein; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins; Vascular Endothelial Growth Factor A; Von Hippel-Lindau Tumor Suppressor Protein

Although D-glucosamine has been reported as an inhibitor of tumor growth both in vivo and in vitro, the mechanism for the anticancer effect of D-glucosamine is still unclear. Since there are several reports suggesting D-glucosamine inhibits protein synthesis, we examined whether D-glucosamine affects p70S6K activity, an important signaling molecule involved in protein translation. In the present study, we found D-glucosamine inhibited the activity of p70S6K and the proliferation of DU145 prostate cancer cells and MDA-MB-231 breast cancer cells. D-glucosamine decreased phosphorylation of p70S6K, and its downstream substrates RPS6, and eIF-4B, but not mTOR and 4EBP1 in DU145 cells, suggesting that D-glucosamine induced inhibition of p70S6K is not through the inhibition of mTOR. In addition, D-glucosamine enhanced the growth inhibitory effects of rapamycin, a specific inhibitor of mTOR. These findings suggest that D-glucosamine can inhibit growth of cancer cells through dephosphorylation of p70S6K.

Topics: Cell Proliferation; Glucosamine; Humans; Neoplasms; Phosphorylation; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Benzenesulfonates; Bevacizumab; Carcinoma, Renal Cell; Clinical Trials as Topic; Drug Evaluation, Preclinical; Humans; Indoles; Neoplasms; Niacinamide; Phenylurea Compounds; Pyridines; Pyrroles; Sirolimus; Sorafenib; Sunitinib; Technology Transfer; Treatment Outcome

The initiation factor eukaryotic translation initiation factor 4E (eIF4E) plays a critical role in initiating translation of mRNAs, including those encoding oncogenic proteins. Therefore, eIF4E is considered a survival protein involved in cell cycle progression, cell transformation, and apoptotic resistance. Phosphorylation of eIF4E (usually at Ser209) increases its binding affinity for the cap of mRNA and may also favor its entry into initiation complexes. Mammalian target of rapamycin (mTOR) inhibitors suppress cap-dependent translation through inhibition of the phosphorylation of eIF4E-binding protein 1. Paradoxically, we have shown that inhibition of mTOR signaling increases eIF4E phosphorylation in human cancer cells. In this study, we focused on revealing the mechanism by which mTOR inhibition increases eIF4E phosphorylation. Silencing of either mTOR or raptor could mimic mTOR inhibitors' effects to increase eIF4E phosphorylation. Moreover, knockdown of mTOR, but not rictor or p70S6K, abrogated rapamycin's ability to increase eIF4E phosphorylation. These results indicate that mTOR inhibitor-induced eIF4E phosphorylation is secondary to mTOR/raptor inhibition and independent of p70S6K. Importantly, mTOR inhibitors lost their ability to increase eIF4E phosphorylation only in cells where both Mnk1 and Mnk2 were knocked out, indicating that mTOR inhibitors increase eIF4E phosphorylation through a Mnk-dependent mechanism. Given that mTOR inhibitors failed to increase Mnk and eIF4E phosphorylation in phosphatidylinositol 3-kinase (PI3K)-deficient cells, we conclude that mTOR inhibition increases eIF4E phosphorylation through a PI3K-dependent and Mnk-mediated mechanism. In addition, we also suggest an effective therapeutic strategy for enhancing mTOR-targeted cancer therapy by cotargeting mTOR signaling and Mnk/eIF4E phosphorylation.

Topics: Adaptor Proteins, Signal Transducing; Animals; Cell Line, Tumor; Enzyme Activation; Enzyme Induction; Eukaryotic Initiation Factor-4E; Humans; Insulin Receptor Substrate Proteins; Insulin-Like Growth Factor I; Intracellular Signaling Peptides and Proteins; Mice; Models, Biological; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Protein Kinases; Protein Serine-Threonine Kinases; Proteins; Proto-Oncogene Proteins c-akt; Receptor, IGF Type 1; Regulatory-Associated Protein of mTOR; Sirolimus; TOR Serine-Threonine Kinases

Everolimus (Eve) has shown good efficacy and safety profiles in clinical trials in combination with low doses of cyclosporine but there is limited experience in other modes, especially with calcineurin inhibitor elimination. We developed a retrospective study to analyze its clinical use after approval in Europe in 2005. Herein we have presented the results of a series of 272 patients followed for the first 6 months after Eve introduction. In 93.8% of cases Eve was introduced after the first month posttransplantation (conversion use), and 6 months after introduction, the CNI had been eliminated in 75% of cases. The main indication for Eve introduction was the diagnosis of a malignant neoplasm (42%), whereas the combined indication of prevention and/or treatment of toxicity, especially nephrotoxicity, accounted for 46.3% of cases. Initial doses were low (1.37 mg/d), but were progressively increased up to 2 mg/d at 6 months. Renal function remained unchanged during the follow-up period, whereas proteinuria moderately increased. Only 5 cases (2%) of acute rejection episodes were observed with excellent patient and graft survivals at 6 months after conversion. Further analysis of this extensive series of patients with a longer follow-up is needed.

Topics: Adult; Aged; Calcineurin Inhibitors; Cell Division; Everolimus; Female; Humans; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Neoplasms; Registries; Retrospective Studies; Sirolimus; Spain

Topics: Animals; Humans; Immunosuppressive Agents; Neoplasms; Organ Transplantation; Protein Kinases; Sirolimus; TOR Serine-Threonine Kinases

Everolimus is a new immunosuppressant with antitumoral properties and few side effects, but limited use in liver transplantation. The aim of the present study was to evaluate the effect on survival and safety of everolimus in post liver transplantation neoplasms in a single center. Ten liver transplant recipients with a posttransplant diagnosis of neoplasm received everolimus during a median of 12.7 (5.5-27.5) months; median survival was 21.3 (7.5-40.5) months. The probability of survival of everolimus group was significantly greater than the observed in a historical cohort of 14 liver recipients with comparable tumors who did not receive everolimus (100%, 90%, 72% vs. 50%, 29%, 14%) at 6, 12, and 24 months, respectively (HR=4.6, 95% confidence interval: 1.3-16.4; P=0.008). During everolimus therapy no patients showed rejection. Renal function improved in three patients. Furthermore, severe adverse effects and infections were infrequent. In summary, everolimus seems safe for liver transplant recipients with cancer and may improve short-term survival, but further studies are needed to determine long-term benefits and safety.

Topics: Adult; Aged; Everolimus; Female; Graft Rejection; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Liver Diseases; Liver Transplantation; Male; Middle Aged; Neoplasms; Sirolimus; Survival Analysis

We have previously shown that PTEN loss confers trastuzumab resistance in ErbB2-overexpressing breast cancer using cell culture, xenograft models, and patient samples. This is a critical clinical problem because trastuzumab is used in a variety of therapeutic regimens, and at the current time, there are no established clinical strategies to overcome trastuzumab resistance. Here, we did preclinical studies on the efficacy of clinically applicable inhibitors of the Akt/mammalian target of rapamycin (mTOR) pathway to restore trastuzumab sensitivity to PTEN-deficient cells.. Cell culture and xenograft models were used to test a panel of clinically applicable, small-molecule inhibitors of the Akt/mTOR signal transduction pathway, a critical pathway downstream of ErbB2, and identify compounds with the ability to restore trastuzumab sensitivity to PTEN-deficient cells.. When trastuzumab was combined with the Akt inhibitor triciribine, breast cancer cell growth was inhibited and apoptosis was induced. In a xenograft model, combination therapy with trastuzumab and triciribine dramatically inhibited tumor growth. The combination of trastuzumab and the mTOR inhibitor RAD001 also slowed breast cancer cell growth in vitro and in vivo.. Combining trastuzumab with inhibitors of the Akt/mTOR pathway is a clinically applicable strategy and combinations of trastuzumab with triciribine or RAD001 are promising regimens for rescue of trastuzumab resistance caused by PTEN loss.

Topics: Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bromodeoxyuridine; Cell Line, Tumor; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Everolimus; Female; Humans; Mice; Mice, SCID; Neoplasm Transplantation; Neoplasms; PTEN Phosphohydrolase; Ribonucleosides; Sirolimus; Trastuzumab

Autophagy is a degradation process of cytoplasmic cellular constituents, which serves as a survival mechanism in starving cells, and it is characterized by sequestration of bulk cytoplasm and organelles in double-membrane vesicles called autophagosomes. Autophagy has been linked to a variety of pathological processes such as neurodegenerative diseases and tumorigenesis, which highlights its biological and medical importance. We have previously characterized the vacuole membrane protein 1 (VMP1) gene, which is highly activated in acute pancreatitis, a disease associated with morphological changes resembling autophagy. Here we show that VMP1 expression triggers autophagy in mammalian cells. VMP1 expression induces the formation of ultrastructural features of autophagy and recruitment of the microtubule-associated protein 1 light-chain 3 (LC3), which is inhibited after treatment with the autophagy inhibitor 3-methiladenine. VMP1 is induced by starvation and rapamycin treatments. Its expression is necessary for autophagy, because VMP1 small interfering RNA inhibits autophagosome formation under both autophagic stimuli. VMP1 is a transmembrane protein that co-localizes with LC3, a marker of the autophagosomes. It interacts with Beclin 1, a mammalian autophagy initiator, through the VMP1-Atg domain, which is essential for autophagosome formation. VMP1 endogenous expression co-localizes with LC3 in pancreas tissue undergoing pancreatitis-induced autophagy. Finally, VMP1 stable expression targeted to pancreas acinar cell in transgenic mice induces autophagosome formation. Our results identify VMP1 as a novel autophagy-related membrane protein involved in the initial steps of the mammalian cell autophagic process.

Topics: Adenine; Animals; Antibiotics, Antineoplastic; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; HeLa Cells; Humans; Membrane Proteins; Mice; Microtubule-Associated Proteins; Neoplasms; Neurodegenerative Diseases; NIH 3T3 Cells; Pancreatitis, Acute Necrotizing; Phagosomes; Protein Binding; Proteins; RNA, Small Interfering; Sirolimus

The inhibition of mTOR is a target for anticancer drugs in posttransplant malignancies. The influence of conversion to sirolimus after malignancy diagnosis was investigated on patient and renal allograft survivals. The 20 renal allograft recipients (4 women, 16 men) of ages 26 to 73 years (mean, 59 years) developed malignancies within 6 to 172 months (mean, 53 months) after transplantation. Three patients developed posttransplant lymphoproliferative disease (PTLD); four, Kaposi sarcoma, three, lung cancer; two, malignant melanoma; two, breast cancer; two, renal cell carcinoma; one, Merkel cell carcinoma; one, cutaneous T-cell lymphoma; one, larynx cancer; and one, gingival cancer. After tumor diagnosis, calcineurin inhibitors, azathioprine, or mycophenolate mofetil (MMF) were discontinued abruptly and sirolimus introduced (2 mg/d; target trough level, 4.0 to 8.0 ng/mL). Prednisone was maintained. The observation time of sirolimus therapy was 4 to 48 months (mean, 14 months). Two patients with PTLD (large B-cell lymphoma) and four with Kaposi sarcoma had full regressions. Eleven patients (larynx cancer, melanoma, breast cancer, T-cell lymphoma, renal cell carcinoma, Merkel cell carcinoma, and skin lymphoma) in addition to sirolimus therapy, underwent oncologic treatment, namely, surgery and/or chemotherapy. Six patients died from disseminated malignancy 4 to 9 months after conversion. One patient with T-cell lymphoma lost his graft; in the remaining patients, serum creatinine level was stable. In conclusion, Conversion to sirolimus resulted in regression of large B-cell lymphoma and Kaposi sarcoma. In patients with advanced or disseminated malignancy, the tumors progressed. Graft function was preserved after conversion to sirolimus.

Topics: Adult; Aged; Antibiotics, Antineoplastic; Female; Humans; Immunosuppressive Agents; Kidney Transplantation; Lymphoma, B-Cell; Lymphoproliferative Disorders; Male; Middle Aged; Neoplasms; Postoperative Complications; Retrospective Studies; Sarcoma, Kaposi; Sirolimus; Transplantation, Homologous

The p70 S6 ribosomal protein kinase 1 (S6K) is a substrate and effector of the mammalian target of rapamycin (mTOR). The mTOR/S6K pathway is implicated in cancer and metabolic disorders. To study the molecular regulation of S6K and identify specific inhibitors, availability of active recombinant S6K and robust enzyme assays are critically needed. To date, however, expression of active recombinant S6K has not been feasible as S6K activation requires a cascade of phosphorylation events. We have compared several engineered S6K enzymes. Expression of the Flag-S6KDeltaCT(T389E) in HEK293 cells resulted in a highly active S6K that was constitutively phosphorylated on T229 in the activation-loop (T-loop). The active enzyme was readily purified in large scale by anti-Flag affinity chromatography achieving a high purity. We developed a high capacity homogeneous time-resolved fluorescence resonance energy transfer. Lance assay for measurement of substrate phosphorylation and analysis of kinetic parameters. The Michaelis constant (Km) values of S6K for ATP and the Biotin-S6 substrate peptide were determined to be 21.4+/-0.29 and 0.9+/-0.48 microM, respectively. The Lance assay was further validated with a diverse panel of literature inhibitors, in which the PKC inhibitors staurosporine, Ro-318220, and the PKA inhibitor Balanol potently inhibited S6K. Dose-response and inhibition mechanism by these inhibitors were also studied. Our data provide a new simplified strategy to achieve rapid production of active S6K and demonstrate utility of the Lance assay for S6K enzyme screen in searching for specific inhibitors.

Topics: Antibiotics, Antineoplastic; Cell Line; Dose-Response Relationship, Drug; Enzyme Inhibitors; Fluorescence Resonance Energy Transfer; Humans; Metabolic Diseases; Neoplasms; Phosphorylation; Protein Kinases; Protein Processing, Post-Translational; Recombinant Proteins; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The PIK3CA gene, coding for the catalytic subunit p110alpha of class IA phosphatidylinositol 3-kinases (PI3Ks), is frequently mutated in human cancer. Mutated p110alpha proteins show a gain of enzymatic function in vitro and are oncogenic in cell culture. Here, we show that three prevalent mutants of p110alpha, E542K, E545K, and H1047R, are oncogenic in vivo. They induce tumors in the chorioallantoic membrane of the chicken embryo and cause hemangiosarcomas in the animal. These tumors are marked by increased angiogenesis and an activation of the Akt pathway. The target of rapamycin inhibitor RAD001 blocks tumor growth induced by the H1047R p110alpha mutant. The in vivo oncogenicity of PIK3CA mutants in an avian species strongly suggests a critical role for these mutated proteins in human malignancies.

Topics: Animals; Antineoplastic Agents; Blotting, Western; Cell Membrane; Cells, Cultured; Chick Embryo; Chickens; Chorioallantoic Membrane; Class I Phosphatidylinositol 3-Kinases; Disease Models, Animal; Hemangiosarcoma; Humans; Microglia; Mutation; Neoplasms; Phosphatidylinositol 3-Kinases; Placebos; Signal Transduction; Sirolimus; Time Factors; Transfection

The PI3K-Akt-mTOR growth-regulating pathway is conserved from mammals to flies and hyperactivated in many cancers. Accordingly, rapamycin analogs, which are inhibitors of mTOR-Raptor signaling, have recently garnered much interest as potential therapeutic agents against cancer. However, due to the heterogeneity of tumors, prior knowledge of the genetic and biochemical background of cancer cells will be required for effective targeted therapy. Thus, the identification of biological markers against activated oncogenic pathways is needed. In the January issue of Nature Medicine, Thomas et al. identify the loss of VHL tumor suppressor gene as a potential determining factor in tumor sensitivity to rapamycin.

Topics: Animals; Class I Phosphatidylinositol 3-Kinases; Humans; Neoplasms; Oncogenes; Phosphatidylinositol 3-Kinases; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Von Hippel-Lindau Tumor Suppressor Protein

We examined the occurrence of neoplasms among 1008 renal transplant recipients treated with a sirolimus-cyclosporine (CsA) +/- prednisone (Pred) regimen.. A comprehensive database of demographic, laboratory, clinical, and histopathologic features of these patients all followed in our transplant center was analyzed using Student t test and Mann-Whitney U test for continuous and chi-square test for categorical variables. Comparisons were performed with information in the Israel Penn International Transplant Tumor Registry (IPITTR).. During the mean patient follow-up of 62.3 +/- 26.1 months (range 27.1 to 131), 36 tumors occurred in 35 patients (3.6%) at 32.5 +/- 29.8 months. The most common neoplasms were skin tumors (2.4%), a value that was significantly lower than the 6% rate observed with CsA-azathioprine-Pred treatment. Also, the 0.4% incidence of posttransplant lymphoproliferative disorders and 0.2% incidence of renal cell carcinomas were less than half of those previously reported with a combination of tacrolimus and mycophenolate mofetil. The distribution of tumor types was similar to that reported to the IPITTR. The mean trough drug concentrations in affected recipients at the time of diagnosis were within the putative target ranges.. Renal transplant recipients treated with the sirolimus-CsA +/- Pred combination showed a low incidence of tumors of similar types as those encountered with other regimens.

Topics: Databases, Factual; Follow-Up Studies; Humans; Immunosuppressive Agents; Incidence; Kidney Transplantation; Neoplasms; Prednisone; Registries; Sirolimus; Treatment Outcome

Topics: Animals; Antineoplastic Agents; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Cell Survival; Chloroquine; Dacarbazine; Genes, Tumor Suppressor; Humans; Membrane Proteins; Mice; Neoplasms; Oncogenes; Proteins; Sirolimus; Temozolomide

Overactivation of the mammalian target of rapamycin (mTOR) branch downstream of the phosphatidylinositol 3-kinase-AKT pathway critically modulates insulin and growth factor signaling by insulin receptor substrates (IRS). On the basis of in vitro studies, the mTOR inhibitor rapamycin has been reported to lead to enhanced activation of AKT by relieving this feedback inhibition on IRS function. In view of the critical role of AKT in insulin signaling and tumorigenesis, the in vivo expression and activation of this kinase and of IRS-1 and IRS-2 were explored in PBMC of 30 patients who were treated long term with rapamycin. A marked decrease of basal and insulin-stimulated AKT phosphorylation, which correlated with the increase of patients' insulin resistance, and a significant increase of IRS total protein expression, together with a lower (IRS-2) or absent (IRS-1) increase of insulin-induced tyrosine phosphorylation, were found. Therefore, contrary to the expectations, long-term exposure to rapamycin caused the impairment of IRS signaling and AKT activation, and this would help to explain the antiproliferative effect and the possible deterioration of glucose metabolism that are observed in rapamycin-treated patients. These findings may form a novel basis for improved understanding of the role of mTOR inhibition in human diseases, such as diabetes and cancer.

Topics: Adult; Cohort Studies; Diabetes Mellitus; Down-Regulation; Enzyme Activation; Female; Humans; Insulin Receptor Substrate Proteins; Intracellular Signaling Peptides and Proteins; Kidney Transplantation; Male; Middle Aged; Models, Biological; Neoplasms; Phosphoproteins; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus

Endothelial cells in growing tumors express activated Akt, which when modeled by transgenic endothelial expression of myrAkt1 was sufficient to recapitulate the abnormal structural and functional features of tumor blood vessels in nontumor tissues. Sustained endothelial Akt activation caused increased blood vessel size and generalized edema from chronic vascular permeability, while acute permeability in response to VEGF-A was unaffected. These changes were reversible, demonstrating an ongoing requirement for Akt signaling for the maintenance of these phenotypes. Furthermore, rapamycin inhibited endothelial Akt signaling, vascular changes from myrAkt1, tumor growth, and tumor vascular permeability. Akt signaling in the tumor vascular stroma was sensitive to rapamycin, suggesting that rapamycin may affect tumor growth in part by acting as a vascular Akt inhibitor.

Topics: Animals; Capillary Permeability; Cells, Cultured; Edema; Endothelial Cells; Endothelium, Vascular; Humans; Mice; Mice, Transgenic; Neoplasms; Neovascularization, Pathologic; Proto-Oncogene Proteins c-akt; Rats; Signal Transduction; Sirolimus; Vascular Endothelial Growth Factor A

Loss of the promyelocytic leukaemia (PML) tumour suppressor has been observed in several human cancers. The tumour-suppressive function of PML has been attributed to its ability to induce growth arrest, cellular senescence and apoptosis. Here we identify PML as a critical inhibitor of neoangiogenesis (the formation of new blood vessels) in vivo, in both ischaemic and neoplastic conditions, through the control of protein translation. We demonstrate that in hypoxic conditions PML acts as a negative regulator of the synthesis rate of hypoxia-inducible factor 1alpha (HIF-1alpha) by repressing mammalian target of rapamycin (mTOR). PML physically interacts with mTOR and negatively regulates its association with the small GTPase Rheb by favouring mTOR nuclear accumulation. Notably, Pml-/- cells and tumours display higher sensitivity both in vitro and in vivo to growth inhibition by rapamycin, and lack of PML inversely correlates with phosphorylation of ribosomal protein S6 and tumour angiogenesis in mouse and human tumours. Thus, our findings identify PML as a novel suppressor of mTOR and neoangiogenesis.

Topics: Animals; Cell Hypoxia; Cell Line, Tumor; Cell Nucleus; Fibroblasts; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Ischemia; Mice; Monomeric GTP-Binding Proteins; Neoplasm Proteins; Neoplasms; Neovascularization, Pathologic; Neuropeptides; Nuclear Proteins; Phosphorylation; Promyelocytic Leukemia Protein; Protein Binding; Protein Biosynthesis; Protein Kinases; Ras Homolog Enriched in Brain Protein; Repressor Proteins; Ribosomal Protein S6; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tumor Suppressor Proteins

Autophagy is an alternative cell death pathway that is induced by mammalian target of rapamycin (mTOR) inhibitors and up-regulated when apoptosis is defective. We investigated radiation-induced autophagy in the presence or absence of Bax/Bak with or without an mTOR inhibitor, Rad001. Two isogenic cell lines, wild type (WT) and Bak/Bak(-/-) mouse embryonic fibroblasts and tumor cell lines were used for this study. Irradiated Bak/Bak(-/-) cells had a decrease of Akt/mTOR signaling and a significant increase of pro-autophagic proteins ATG5-ATG12 COMPLEX and Beclin-1. These molecular events resulted in an up-regulation of autophagy. Bax/Bak(-/-) cells were defective in undergoing apoptosis but were more radiosensitive than the WT cells in autophagy. Both autophagy and sensitization of Bak/Bax(-/-) cells were further enhanced in the presence of Rad001. In contrast, inhibitors of autophagy rendered the Bak/Bax(-/-) cells radioresistant, whereas overexpression of ATG5 and Beclin-1 made the WT cells radiosensitive. When this novel concept of radiosensitization was tested in cancer models, small interfering RNAs against Bak/Bax also led to increased autophagy and sensitization of human breast and lung cancer cells to gamma radiation, which was further enhanced by Rad001. This is the first report to demonstrate that inhibition of pro-apoptotic proteins and induction of autophagy sensitizes cancer cells to therapy. Therapeutically targeting this novel pathway may yield significant benefits for cancer patients.

Topics: Animals; Apoptosis; Autophagy; bcl-2 Homologous Antagonist-Killer Protein; bcl-2-Associated X Protein; Cell Line, Tumor; Dose-Response Relationship, Radiation; Everolimus; Humans; Immunosuppressive Agents; Mice; Mice, Knockout; Neoplasms; Protein Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Conversion from calcineurin inhibitors (CNI) to sirolimus (SRL) is an option for renal transplant patients who develop a tumor. This strategy, however, may be associated with an increased risk of rejection.. We sought to evaluate a series of renal transplant patients who underwent conversion from CNI to SRL because they developed a tumor during the posttransplant period.. This prospective study of 29 patients included 2 patients with skin cancer (1 melanoma and 1 squamous cell carcinoma) and 27 patients who developed other tumors: lung (n = 6), prostate (n = 4), lymphoma (n = 2), colon adenocarcinoma (n = 2), kidney (n = 2), Kaposi sarcoma (n = 2), urothelium (n = 1), parotid (n = 1), larynx (n = 1), gastric (n = 1), breast (n = 1), tongue (n = 1), liver (n = 1), xanthoastrocytoma (n = 1), and aggressive angiomyxoma of the perineum (n = 1).. CNI were withdrawn in 28 patients and reduced in the remaining patient. Renal function was better when CNI were rapidly or abruptly suspended, with maintenance of cyclosporine (CsA) + SRL for more than 3 months being especially detrimental. Proteinuria worsened in patients whose preconversion levels were >0.5 g/d, particularly those treated with CsA. There was no episode of rejection.. SRL is a promising option for the management of posttransplant tumors. The switch in immunosuppression should be undertaken quickly, especially in patients under treatment with CsA.

Topics: Creatinine; Follow-Up Studies; Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Postoperative Complications; Sirolimus

Cancer has been reported to be more common among kidney transplant recipients than waiting-list patients or the general population. Use of anticalcineurin agents and azathioprine are relevant risk factors. Nine renal allograft recipients (seven men and two women) of mean age 67.6 (55-77) years and mean time after transplantation of 30.7 (58-216) months were switched to everolimus-based immunosuppression because of the presence of biopsy-proven malignancies (eight patients) or neurological tacrolimus toxicity (one patient). One patient with posttransplant lymphoproliferative disease also received chemotherapy with a good evolution at 6 months. He showed an initial increase in the protein to creatinine ratio (peak 3.3 mg/mg at 3 months) that was controlled by increasing the enalapril dose. One patient with skin cancer and severe atheromatosis (baseline SCr 2.5 mg/dL, creatinine clearance 17 mL/min, and protein to creatinine ratio 3.2 mg/mg), had cyclosporine and everolimus overlapped for 25 days, showing a continued poor evolution requiring dialysis initiation at 3 months after switch. The other six patients with recurrent skin cancers had good cancer evolution, with no new skin tumors and regression of skin lesions in three, including not biopsied actinic keratosis. Sudden switching from calcineurin inhibitors to everolimus is safe and may be used in long-term transplant recipients with malignancies. In patients with advanced chronic nephropathy this approach appeared to be less beneficial.

Topics: Aged; Antineoplastic Agents; Cadaver; Calcineurin Inhibitors; Everolimus; Female; Humans; Immunosuppressive Agents; Kidney Transplantation; Middle Aged; Neoplasms; Recurrence; Sirolimus; Skin Neoplasms; Tissue Donors; Treatment Outcome

Sirolimus (SRL) is a new, potent immunosuppressive agent. More recently, proteinuria has been reported as a consequence of sirolimus therapy, although the mechanism has remained unclear. We retrospectively examined the records of 25 renal transplant patients, who developed or displayed increased proteinuria after SRL conversion. The patient cohort (14 men, 11 women) was treated with SRL as conversion therapy, due to chronic allograft nephropathy (CAN) (n = 15) neoplasia (n = 8); Kaposi's sarcoma, Four skin cancers, One intestinal tumors, One renal cell carsinom) or BK virus nephropathy (n = 2). SRL was started at a mean of 78 +/- 42 (15 to 163) months after transplantation. Mean follow-up on SRL therapy was 20 +/- 12 (6 to 43) months. Proteinuria increased from 0.445 (0 to 1.5) g/d before conversion to 3.2 g/dL (0.2 to 12) after conversion (P = 0.001). Before conversion 8 (32%) patients had no proteinuria, whereas afterwards all patients had proteinuria. In 28% of patients proteinuria remained unchanged, whereas it increased in 68% of patients. In 40% it increased by more than 100%. Twenty-eight percent of patients showed increased proteinuria to the nephrotic range. Biopsies performed in five patients revealed new pathological changes: One membranoproliferative glomerulopathy and interstitial nephritis. These patients showed persistently good graft function. Serum creatinine values did not change significantly: 1.98 +/- 0.8 mg/dL before SRL therapy and 2.53 +/- 1.9 mg/dL at last follow-up (P = .14). Five grafts were lost and the patients returned to dialysis. Five patients displayed CAN and Kaposi's sarcoma. Mean urinary protein of patients who returned to dialysis was 1.26 (0.5 to 3.5) g/d before and 4.7 (3 to 12) g/d after conversion (P = .01). Mean serum creatinine level before conversion was 2.21 mg/dL and thereafter, 4.93 mg/dL (P = .02). Heavy proteinuria was common after the use of SRL as rescue therapy for renal transplantation. Therefore, conversion should be considered for patients who have not developed advanced CAN and proteinuria. The possibility of de novo glomerular pathology under SRL treatment requires further investigation by renal biopsy.

Topics: Adult; Cadaver; Creatinine; Female; Humans; Immunosuppressive Agents; Kidney Function Tests; Kidney Transplantation; Living Donors; Male; Middle Aged; Neoplasms; Postoperative Complications; Proteinuria; Retrospective Studies; Sirolimus; Tissue Donors

Kidney transplantation (KTx) recipients are at a higher risk of oncogenesis when compared to the general population. Sirolimus (SRL), a potent immunosuppressant, has shown promising antineoplastic effects in vitro and in vivo. This study retrospectively analyzed the neoplasm occurrence and the efficiency of SRL on unresectable malignancies in South Chinese KTx recipients. Thirty-three (1.64%) of 2017 patients who received KTx from January 1984 to December 2004 developed neoplasms at 4 to 117 months posttransplant, mostly in digestive organs (33.3%), the hematologic system (15.2%), or the skin (12.1%). The most common type was liver cancer (24.2%), followed by skin cancer, lymphoma, and thyroid cancer (9.1%). The median survival times were 41.5 and 6.0 months for those who did (n = 10) receive radical surgery or did not (n = 23), respectively. The 20-month survival rates were 70.0% versus 13.0% (P < .01). For unresectable patients, the median survival time of those treated with SRL (n = 8) was 14.5 months compared to 3.0 months for those who did not (n = 15). The survival rates at 12(th) and 20(th) months were 75.0% and 37.5% in the SRL group and 6.7% and 0% in the non-SRL group (P < .05). In conclusion, when compared with Western studies, a lower incidence and unique location pattern (liver cancer-dominant) are characteristics of de novo posttransplant neoplasms in South Chinese KTx recipients. Early diagnosis and feasible radical surgery are favorable for prognosis, and SRL is a treatment of choice for KTx recipients with neoplasms.

Topics: China; Follow-Up Studies; Humans; Immunosuppressive Agents; Kidney Transplantation; Liver Neoplasms; Neoplasms; Postoperative Complications; Retrospective Studies; Sirolimus; Survival Analysis; Time Factors

Rapamycin has antiangiogenic activity against tumors. This has been discussed while addressing the problem of cancer in organ transplantation. Here we investigated effective dosing schedules against tumors and angiogenesis. Growth of established CT-26 colon adenocarcinoma tumors was measured in Balb/c mice treated with total equivalent rapamycin doses (1.5 mg/kg/day) given once a day, once every 3 days, or by continuous infusion. Tumors were most inhibited with continuous rapamycin infusion, and less by bolus dosing. Interestingly, however, continuous dosing produced the lowest rapamycin blood levels (15 ng/ml). As rapamycin-sensitive p70S6-kinase intracellular signaling is critical for angiogenesis, p70S6-kinase activation was measured in endothelial cells by Western blotting. Maximal p70S6-kinase inhibition occurred from 1-5 ng/ml rapamycin. These same rapamycin concentrations optimally blocked vessel-sprouting from cultured aortic rings. Therefore, low-level rapamycin dosing most effectively controls tumors in mice. Importantly, antiangiogenic rapamycin levels are compatible with immunosuppressive doses, supporting its potential use in transplant patients with cancer.

Topics: Adenocarcinoma; Angiogenesis Inhibitors; Animals; Aorta, Thoracic; Cell Line, Tumor; Cells, Cultured; Colonic Neoplasms; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelium, Vascular; Humans; Male; Mice; Mice, Inbred BALB C; Neoplasms; Rats; Rats, Inbred Lew; Sirolimus

Therapeutic strategies that target and disrupt the already-formed vessel networks of growing tumors are actively pursued. The goal of these approaches is to induce a rapid shutdown of the vascular function of the tumor so that blood flow is arrested and tumor cell death occurs. Here we show that the mammalian target of rapamycin (mTOR) inhibitor rapamycin, when administered to tumor-bearing mice, selectively induced extensive local microthrombosis of the tumor microvasculature. Importantly, rapamycin administration had no detectable effect on the peritumoral or normal tissue. Intravital microscopy analysis of tumors implanted into skinfold chambers revealed that rapamycin led to a specific shutdown of initially patent tumor vessels. In human umbilical vein endothelial cells vascular endothelial growth factor (VEGF)-induced tissue factor expression was strongly enhanced by rapamycin. We further show by Western blot analysis that rapamycin interferes with a negative feedback mechanism controlling this pathologic VEGF-mediated tissue factor expression. This thrombogenic alteration of the endothelial cells was confirmed in a one-step coagulation assay. The circumstance that VEGF is up-regulated in most tumors may explain the remarkable selectivity of tumor vessel thrombosis under rapamycin therapy. Taken together, these data suggest that rapamycin, besides its known antiangiogenic properties, has a strong tumor-specific, antivascular effect in tumors.

Topics: Angiogenesis Inhibitors; Animals; Endothelium, Vascular; Feedback, Physiological; Humans; Mice; Microcirculation; Microscopy, Video; Neoplasm Transplantation; Neoplasms; Sirolimus; Thromboplastin; Thrombosis; Vascular Endothelial Growth Factor A

The Akt kinases promote hematopoietic cell growth and accumulation through phosphorylation of apoptotic effectors and stimulation of mTOR-dependent translation. In Akt-transformed leukemic cells, tumor growth can be inhibited by the mTOR inhibitor rapamycin, and clinical trials of rapamycin analogs for the treatment of leukemia are under way. Surprisingly, nontransformed hematopoietic cells can grow and proliferate in the presence of rapamycin. Here, we show that Pim-2 is required to confer rapamycin resistance. Primary hematopoietic cells from Pim-2- and Pim-1/Pim-2-deficient animals failed to accumulate and underwent apoptosis in the presence of rapamycin. Although animals deficient in Akt-1 or Pim-1/Pim-2 are viable, few animals with a compound deletion survived development, and those that were born had severe anemia. Primary hematopoietic cells from Akt-1/Pim-1/Pim-2-deficient animals displayed marked impairments in cell growth and survival. Conversely, ectopic expression of either Pim-2 or Akt-1 induced increased cell size and apoptotic resistance. However, though the effects of ectopic Akt-1 were reversed by rapamycin or a nonphosphorylatable form of 4EBP-1, those of Pim-2 were not. Coexpression of the transgenes in mice led to additive increases in cell size and survival and predisposed animals to rapid tumor formation. Together, these data indicate that Pim-2 and Akt-1 are critical components of overlapping but independent pathways, either of which is sufficient to promote the growth and survival of nontransformed hematopoietic cells.

Topics: Animals; Apoptosis; Bone Marrow Cells; Cell Proliferation; Cell Survival; Cells, Cultured; Hematopoiesis; Hematopoietic Stem Cells; Mice; Mice, Transgenic; Neoplasms; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-pim-1; Sirolimus; Transduction, Genetic

Recent studies indicate that dysregulation of the Akt/PKB family of serine/threonine kinases is a prominent feature of many human cancers. The Akt/PKB family is composed of three members termed Akt1/PKBalpha, Akt2/PKBbeta, and Akt3/PKBgamma. It is currently not known to what extent there is functional overlap between these family members. We have recently identified small molecule inhibitors of Akt. These compounds have pleckstrin homology domain-dependent, isozyme-specific activity. In this report, we present data showing the relative contribution that inhibition of the different isozymes has on the apoptotic response of tumor cells to a variety of chemotherapies. In multiple cell backgrounds, maximal induction of caspase-3 activity is achieved when both Akt1 and Akt2 are inhibited. This induction is not reversed by overexpression of functionally active Akt3. The level of caspase-3 activation achieved under these conditions is equivalent to that observed with the phosphatidylinositol-3-kinase inhibitor LY294002. We also show that in different tumor cell backgrounds inhibition of mammalian target of rapamycin, a downstream substrate of Akt, is less effective in inducing caspase-3 activity than inhibition of Akt1 and Akt2. This shows that the survival phenotype conferred by Akt can be mediated by signaling pathways independent of mammalian target of rapamycin in some tumor cell backgrounds. Finally, we show that inhibition of both Akt1 and Akt2 selectively sensitizes tumor cells, but not normal cells, to apoptotic stimuli.

Topics: 3-Phosphoinositide-Dependent Protein Kinases; Antibiotics, Antineoplastic; Apoptosis; Caspase 3; Caspases; Chromones; Drug Resistance, Neoplasm; Enzyme Activation; Humans; Morpholines; Neoplasms; Protein Isoforms; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Sirolimus; Tumor Cells, Cultured

Deregulated phosphatidylinositol 3-kinase (PI3K) signaling pathway is widely implicated in tumor growth and resistance to chemotherapy. While a strong rationale exists for pharmacological targeting of PI3K, only a few proof-of-principle in vivo efficacy studies are currently available. PWT-458, pegylated-17-hydroxywortmannin, is a novel and highly potent inhibitor of PI3K in animal models. Upon in vivo cleavage of its poly(ethyleneglycol) (PEG), PWT-458 releases its active moiety 17-hydroxywortmannin (17-HWT), the most potent inhibitor in its class. Here we show that a single intravenous injection of PWT-458 rapidly inhibited PI3K signaling, as measured by a complete loss of AKT (Ser-473) phosphorylation in xenograft tumors grown in nude mice. Following a daily X5 dosing regimen, PWT-458 demonstrated single-agent antitumor activity in nude mouse xenograft models of U87MG glioma, nonsmall cell lung cancer (NSCLC) A549, and renal cell carcinoma (RCC) A498. Efficacious doses ranged from 0.5 mg/kg to 10 mg/kg, achieving a superior therapeutic index over 17-HWT. PWT-458 augmented anticancer efficacy of a suboptimal dose of paclitaxel against A549 and U87MG tumors. Combination treatment of PWT-458 and an mTOR inhibitor, Pegylated-Rapamycin (Peg-Rapa), resulted in an enhanced antitumor efficacy in U87MG. Finally, PWT-458 in combination with interferon-alpha (Intron-A) caused a dramatic regression of RCC A498, which was not achieved by either agent alone. These studies identify PWT-458 as an effective anticancer agent and provide strong proof-of-principle for targeting the PI3K pathway as novel anticancer therapy.

Topics: Androstadienes; Animals; Antibiotics, Antineoplastic; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Carcinoma, Non-Small-Cell Lung; Carcinoma, Renal Cell; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Synergism; Drug Therapy, Combination; Female; Glioma; Humans; Interferon-alpha; Kidney Neoplasms; Lung Neoplasms; Mice; Mice, Nude; Molecular Structure; Molecular Weight; Neoplasm Transplantation; Neoplasms; Paclitaxel; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; Transplantation, Heterologous; Xenograft Model Antitumor Assays

Gap junctions are composed of connexins and are critical for the maintenance of the differentiated state. Consistently, connexin expression is impaired in most cancer cells, and forced expression of connexins following cDNA transfection reverses the tumor phenotype. We have found that the restoration of density inhibition of human pancreatic cancer cells by the antiproliferative somatostatin receptor 2 (sst2) is due to overexpression of endogenous connexins Cx26 and Cx43 and consequent formation of functional gap junctions. Immunoblotting along with protein metabolic labeling and mRNA monitoring revealed that connexin expression is enhanced at the level of translation but is not sensitive to the inhibition of cap-dependent translation initiation. Furthermore, we identified a new internal ribosome entry site (IRES) in the Cx26 mRNA. The activity of Cx26 IRES and that of the previously described Cx43 IRES are enhanced in density-inhibited cells. These data indicate that the restoration of functional gap junctions is likely a critical event in the antiproliferative action of the sst2 receptor. We further suggest that the existence of IRESes in connexin mRNAs permits connexin expression in density-inhibited or differentiated cells, where cap-dependent translation is generally reduced.

Topics: 5' Untranslated Regions; Cell Communication; Cell Count; Cell Line, Tumor; Cell Proliferation; Connexin 26; Connexin 43; Connexins; Gap Junctions; Humans; Neoplasms; Protein Biosynthesis; Receptors, Somatostatin; Regulatory Sequences, Nucleic Acid; Ribosomes; Sirolimus; Up-Regulation

Topics: Humans; Immunosuppressive Agents; Kidney Transplantation; Neoplasms; Sarcoma, Kaposi; Sirolimus

Malignancies, a well-known complication of immunosuppressive therapy in renal transplant recipients, represent an important cause of long-term morbidity and mortality. One approach to addressing this problem is identifying agents that display antineoplastic properties concomitant with their immunosuppressive effects.. We examined the neoplasms among 1008 renal transplant recipients treated at a single center with sirolimus-cyclosporine +/- prednisone.. Clinical and laboratory data, including 62.3+/-26.1 months follow-up (range 27.1-131), revealed 36 tumors in 35 patients (3.6%) presenting at 32.5+/-29.8 months. The 2.4% incidence of skin tumors, the most common neoplasms, was 1.58-fold greater than the general U.S. population. In addition to a 0.4% incidence of posttransplant lymphoproliferative disorders (PTLD) and a 0.2% incidence of renal cell carcinomas, we observed single cases of breast, bladder, endometrial, lung, and brain neoplasms as well as leukemia. The mean trough drug concentrations at the time of diagnosis in affected recipients were within our putative target ranges. In addition to eleven graft losses due to death with a functioning kidney, two were related to chronic rejection following reduced immunosuppression, and one, therapeutic nephrectomy for PTLD. Five of twelve deaths were caused by malignancies; four others among 1008 patients over the entire follow-up were attributed to cardiovascular events; one, to respiratory failure; and two, at distant locations to unknown causes.. The sirolimus-cyclosporine +/- prednisone combination appears likely to be associated with a reduced incidence of tumors.

Topics: Adolescent; Adult; Aged; Cyclosporine; Female; Humans; Immunosuppressive Agents; Incidence; Kidney Transplantation; Male; Middle Aged; Neoplasms; Risk Factors; Sirolimus; Treatment Outcome

Topics: Animals; Antineoplastic Agents; Disease Models, Animal; Everolimus; Humans; Immunosuppressive Agents; Mice; Mice, Transgenic; Neoplasms; Protein Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Sirolimus; TOR Serine-Threonine Kinases

We examined the rates of malignancy at 2 yr after transplantation in renal allograft patients receiving sirolimus (SRL) in continuous combination with cyclosporine (CsA), SRL as base therapy or SRL maintenance therapy after early withdrawal of CsA. A total of 1295 patients were enrolled in two double-blind studies comparing SRL with azathioprine (AZA) or placebo administered in continuous regimens with CsA. In two other trials (n = 161), SRL given as base therapy was compared with CsA. In the fifth trial, patients were randomly assigned at 3 months to either remain on CsA + SRL therapy (n = 215) or to have CsA eliminated with SRL being continued in concentration-controlled doses (n = 215). At 2 yr after transplantation, patients receiving SRL in continuous combination with CsA had a significantly lower incidence of skin cancer compared with patients receiving placebo. Patients receiving SRL as base therapy had no malignancies compared with a 5% incidence in those receiving CsA. The incidence of malignancy was significantly lower in patients receiving concentration-controlled SRL with elimination of CsA compared with those who remained on CsA + SRL. Based on the currently available data, patients receiving SRL-based therapy without CsA or SRL maintenance therapy after early CsA withdrawal have lower rates of malignancy in the first 2 yr after renal transplantation. SRL immunotherapy may be beneficial in protecting renal transplant patients from skin cancer even when given in combination with CsA.

Topics: Chemoprevention; Cyclosporine; Drug Therapy, Combination; Humans; Immunosuppressive Agents; Incidence; Kidney Transplantation; Multicenter Studies as Topic; Neoplasms; Neoplasms, Second Primary; Retrospective Studies; Sirolimus; Skin Neoplasms

Topics: Acetyltransferases; Apoptosis; Cell Hypoxia; Everolimus; Histone Acetyltransferases; Neoplasms; Neovascularization, Pathologic; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Sirolimus

Topics: Adenine Nucleotides; Antineoplastic Agents; Arabinonucleosides; Cancer Vaccines; Clofarabine; Cytokines; Epidermal Growth Factor; Glucocorticoids; Humans; Interleukin-2; Metalloporphyrins; Neoplasms; Proto-Oncogene Proteins c-bcl-2; Sirolimus

CCI-779 is an ester of rapamycin and inhibitor of mammalian target of rapamycin (mTOR) currently in Phase II clinical development for the treatment of patients with cancer. CCI-779 interacts with mTOR and inhibits its kinase activity, resulting in inhibition of the mTOR-regulated translational controllers p70(s6) kinase and 4E-BP1. Ultimately, CCI-779 decreases the translation of mRNAs involved in the control of the cell cycle, resulting in cell cycle arrest. The objective of this study was to develop a method to determine the pharmacodynamic effects of CCI-779 suitable for use in clinical trials. Exposure of Raji lymphoblastoid cells to increasing concentrations of rapamycin resulted in a linear concentration-dependent inhibition of p70(s6) kinase activity, suggesting that p70(s6) kinase activity could be an appropriate marker for mTOR-interacting agents. In subsequent experiments, treatment of nude mice bearing the CCI-779 susceptible breast cancer cell line MDA-468 with a single dose of 10 mg/kg CCI-779 resulted in a >80% inhibition of p70(s6) kinase activity in peripheral blood mononuclear cells (PBMCs) 72 h after treatment. Importantly, the degree of p70(s6) kinase inhibition was identical in PBMCs and simultaneously collected tumor tissue, suggesting that the PBMCs are an adequate surrogate tissue for p70(s6) kinase activity in vivo. The intrasubject coefficient of variation of p70(s6) kinase activity measured in PBMCs collected from five healthy volunteers on days 1, 4, and 8 was 14%, indicating that p70(s6) kinase activity in PBMCs remains relatively stable over time. Finally, p70(s6) kinase activity was measured in PBMCs from nine patients with renal cell cancer treated with a single dose of 25, 75, or 250 mg of CCI-779 i.v. (three patients each). PBMCs were collected on days 2, 4, and 8 after CCI-779 treatment. In this small data set, eight of the nine patients had evidence of p70(s6) kinase activity inhibition after treatment that was independent of the administered dose. There was a significant linear association between time to disease progression and inhibition of p70(s6) kinase activity 24 h after treatment. In conclusion, these results indicate that the pharmacodynamic effects of CCI-779 can be determined using a p70(s6) kinase assay in PBMCs. This assay is currently being incorporated in Phase I and II studies with CCI-779 to determine its relationship with dose and plasma concentration of the agent and its value as a predictor of treatme

Topics: Animals; Antibiotics, Antineoplastic; Carcinoma, Renal Cell; Cell Cycle; Cell Line, Tumor; Clinical Trials as Topic; Disease Progression; Dose-Response Relationship, Drug; Female; Humans; Immunoblotting; Kidney Neoplasms; Leukocytes, Mononuclear; Mice; Mice, Nude; Neoplasm Transplantation; Neoplasms; Neoplasms, Experimental; Protein Kinase Inhibitors; Protein Kinases; Sirolimus; Time Factors; TOR Serine-Threonine Kinases

Kidney transplant recipients require careful follow-up in both the early (< 6 months) and late posttransplant periods. Monitoring should focus on graft function and the most common complications of immunosuppression therapy. Infections, especially CMV infection, require particular attention in the first few months after transplantation, when immunosuppression is most intense. In both the early and the late posttransplant periods, an emphasis should be placed on intensive management of CVD risk factors (e.g., hypertension, hyperlipidemia, cigarette smoking). Screening for malignancies known to occur with a high incidence after transplantation is also important. With the improved short-term survival rates brought about by new, potent immunosuppressive agents, emphasis has now shifted to the prevention and treatment of posttransplant complications in kidney transplant recipients. A heightened awareness of these complications, along with a cooperative effort between primary care physicians and transplant programs, offers the best hope for further improvement in outcomes after kidney transplantation.

Topics: Cardiovascular Diseases; Cyclosporine; Cytomegalovirus Infections; Glucocorticoids; Humans; Immunosuppressive Agents; Kidney Transplantation; Metabolic Diseases; Monitoring, Physiologic; Neoplasms; Risk Assessment; Sirolimus; Tacrolimus; Transplantation, Homologous

The mitogen-stimulated serine/threonine kinase p70S6k plays an important role in the progression of cells from G0/G1 to S phase of the cell cycle by translational up-regulation of a family of mRNA transcripts family of mRNA transcripts which contain polypyrimidine tract at their 5 transcriptional start site. Here, we report that p70S6k was constitutively phosphorylated and activated to various degrees in serum-deprived AGS, A2058, HT-1376, MG63, MCF7, MDA-MB-435S, MDA-MB-231 and MB-157. Rapamycin treatment induced a significant dephosphorylation and inactivation of p70S6k in all cancer cell lines, while wortmannin, a specific inhibitor of PI3-K, caused a mild dephosphorylation of p70S6k in AGS, MDA-MB-435S and MB-157. In addition, SQ20006, methylxanthine phosphodiesterase inhibitor, reduced the phosphorylation of p70S6k in all cancer cells tested. Consistent with inhibitory effect of rapamycin on p70S6k activity, rapamycin inhibited [3H]-thymidine incorporation and increased the number of cells at G0/G1 phase. Furthermore, these inhibitory effects were accompanied by the decrease in growth of cancer cells. Taken together, the results indicate that the antiproliferative activity of rapamycin might be attributed to cell cycle arrest at G0/G1 phase in human cancer cells through the inhibition of constitutively activated p70S6k of cancer cells and suggest p70S6k as a potential target for therapeutic strategies aimed at preventing or inhibiting tumor growth.

Topics: Cell Cycle; Enzyme Activation; Enzyme Inhibitors; Humans; Neoplasms; Ribosomal Protein S6 Kinases, 70-kDa; Sirolimus; Tumor Cells, Cultured

Topics: Animals; Antineoplastic Agents; Benzamides; Benzoquinones; Cell Cycle Proteins; DNA-Binding Proteins; E2F Transcription Factors; Gefitinib; Genes, Tumor Suppressor; HSP90 Heat-Shock Proteins; Humans; Imatinib Mesylate; Indoles; Lactams, Macrocyclic; Mutation; Neoplasms; Phosphoric Monoester Hydrolases; Piperazines; PTEN Phosphohydrolase; Pyrimidines; Pyrroles; Quinazolines; Rifabutin; Signal Transduction; Sirolimus; Transcription Factors; Tumor Suppressor Proteins

Topics: Cell Cycle Proteins; Clinical Trials, Phase I as Topic; Fungal Proteins; Graft Rejection; Humans; Molecular Weight; Neoplasms; Phosphatidylinositol 3-Kinases; Phosphotransferases (Alcohol Group Acceptor); Protein Isoforms; Protein Kinases; Saccharomyces cerevisiae Proteins; Sirolimus; TOR Serine-Threonine Kinases

The rapamycin ester, CCI-779, potently inhibits cell growth in vitro, inhibits tumor growth in vivo, and is currently in Phase I clinical trials. To further understand the relationship between plasma systemic exposure and inhibition of the target Ser/Thr kinase, mTOR/FRAP, two assays have been developed. The first assay involves determination of the 4E suppressor protein (4E-BP1) bound to eukaryotic initiation factor 4E (eIF4E), and the second is direct Western analysis of phosphorylation of residue Thr(70) of 4E-BP1. Under normal growth conditions in vitro, rapamycin caused rapid association of 4E-BP1 with eIF4E within 1 h in Rh30 and GC(3) human tumor cells. Association was persistent up to 16 h. In mice, administration of rapamycin (5 or 20 mg/kg) caused rapid association of 4E-BP1 with eIF4E within 4 h in both human colon adenocarcinoma GC(3) and rhabdomyosarcoma Rh30 xenografts. Using phospho-specific antibody against Thr(70) of 4E-BP1, rapid and persistent dephosphorylation within 30 min of exposure to rapamycin was detected in Rh18 rhabdomyosarcoma cells. Evaluation of CCI-779 against Rh18 xenografts showed this tumor to be growth inhibited at daily dose levels of > or =8.7 mg/kg. Because immunoblotting may be more suitable for assaying tumor biopsy tissue, a "blinded" comparison between the effect of CCI-779 on Thr(70) phosphorylation and growth inhibition of human tumor xenografts was undertaken. Mice were treated daily for 5 days with CCI-779 (20 mg/kg/day) or with drug vehicle, and tumor diameters were measured. Tumors were excised 1 h after the final administration and frozen, and phospho Thr(70) was determined by Western blot analysis. The correlation coefficient for decreases in Thr(70) phosphorylation and growth inhibition was high (r(2), 0.99). The results indicate that an assay of decreases in phosphorylation of Thr(70) of 4E-BP1 may be a useful surrogate for determining the inhibition of mTOR activity in tumor specimens.

Topics: Adaptor Proteins, Signal Transducing; Adenocarcinoma; Animals; Antibiotics, Antineoplastic; Blotting, Western; Carrier Proteins; Cell Cycle Proteins; Cell Division; Eukaryotic Initiation Factor-4E; Eukaryotic Initiation Factors; Humans; Immunoblotting; Mice; Mice, Inbred CBA; Neoplasm Transplantation; Neoplasms; Peptide Initiation Factors; Phosphoproteins; Phosphorylation; Protein Binding; Rhabdomyosarcoma; Sirolimus; Time Factors; Tumor Cells, Cultured

SIROLIMUS: The leading member of the mTOR inhibitor family, sirolimus or rapamycin, has dose-dependent side effects that can generally be well controlled. Sirolimus can be combined with tacrolimus at therapeutic doses; likewise for the sirolimus-cyclosporine combination at moderate dosage. Effective plasma concentrations of sirolimus vary from 5 to 20 ng/ml depending on the combination of immunosuppressant agents used. Sirolimus has been shown to inhibit metastatic diffusion of renal adenocarcinoma in the mouse. Its complex side effects on angiogenesis, fibrosis processes and chronic rejection are still being investigated. EVEROLIMUS: Everolimus, or RAD, has a very short half-life, but induces fewer hematologic effects. The therapeutic dose must reach at least 3 ng/ml to prevent rejection. Doses above 15 ng/ml increase the risk of thrombocytopenia. FTY 720: A new immunosuppressant agent, FTY 720, does not belong to any known family. It has a totally different mechanism of action compared with currently available immunosuppressants. FTY 720 increases the expression of chemokine receptors on the surface of T cells making them unavailable for the rejection reaction. FTY 720 has a very long half-life (108 hours). Due to its particular liver metabolism, there is a very low risk of drug interactions.

Topics: Cyclosporine; Drug Interactions; Drug Therapy, Combination; Everolimus; Fingolimod Hydrochloride; Hyperlipidemias; Immunosuppressive Agents; Kidney; Neoplasms; Propylene Glycols; Sirolimus; Sphingosine

Topics: Animals; Antineoplastic Agents; Cell Cycle; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Drug Evaluation, Preclinical; Drug Industry; Genes, Tumor Suppressor; Humans; Immunosuppressive Agents; Neoplasm Proteins; Neoplasms; Neoplasms, Experimental; Phosphoric Monoester Hydrolases; Phosphorylation; Protein Kinase Inhibitors; Protein Kinases; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Suppressor Proteins