sirolimus has been researched along with Glioma* in 68 studies
3 review(s) available for sirolimus and Glioma
Article | Year |
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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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Pneumonia; Pneumonia, Viral; Point-of-Care Testing; Polyethylene Glycols; Polymers; Polysorbates; Pore Forming Cytotoxic Proteins; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Postprandial Period; Poverty; Pre-Exposure Prophylaxis; Prediabetic State; Predictive Value of Tests; Pregnancy; Pregnancy Trimester, First; Pregnancy, High-Risk; Prenatal Exposure Delayed Effects; Pressure; Prevalence; Primary Graft Dysfunction; Primary Health Care; Professional Role; Professionalism; Prognosis; Progression-Free Survival; Prolactin; Promoter Regions, Genetic; Proof of Concept Study; Proportional Hazards Models; Propylene Glycol; Prospective Studies; Prostate; Protein Binding; Protein Biosynthesis; Protein Isoforms; Protein Kinase Inhibitors; Protein Phosphatase 2; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases; Protein Structure, Tertiary; Protein Transport; Proteoglycans; Proteome; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-myc; Proto-Oncogene Proteins c-ret; Proto-Oncogene Proteins p21(ras); Proton Pumps; Protons; Protoporphyrins; Pseudomonas aeruginosa; Pseudomonas fluorescens; Pulmonary Artery; Pulmonary Disease, Chronic Obstructive; Pulmonary Gas Exchange; Pulmonary Veins; Pyrazoles; Pyridines; Pyrimidines; Qualitative Research; Quinoxalines; Rabbits; Random Allocation; Rats; Rats, Sprague-Dawley; Rats, Wistar; Receptors, Histamine H3; Receptors, Immunologic; Receptors, Transferrin; Recombinant Proteins; Recurrence; Reference Values; Referral and Consultation; Regional Blood Flow; Registries; Regulon; Renal Insufficiency, Chronic; Reperfusion Injury; Repressor Proteins; Reproducibility of Results; Republic of Korea; Research Design; Resistance Training; Respiration, Artificial; Respiratory Distress Syndrome; Respiratory Insufficiency; Resuscitation; Retinal Dehydrogenase; Retreatment; Retrospective Studies; Reverse Transcriptase Inhibitors; Rhinitis, Allergic; Ribosomal Proteins; Ribosomes; Risk Assessment; 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STAT3 Transcription Factor; Streptomyces coelicolor; Stress, Psychological; Stroke; Stroke Volume; Structure-Activity Relationship; Students, Medical; Students, Pharmacy; Substance Abuse Treatment Centers; Sulfur Dioxide; Surface Properties; Surface-Active Agents; Surveys and Questionnaires; Survival Analysis; Survival Rate; Survivin; Sweden; Swine; Swine, Miniature; Sympathetic Nervous System; T-Lymphocytes, Regulatory; Talaromyces; Tandem Mass Spectrometry; tau Proteins; Telemedicine; Telomerase; Telomere; Telomere Homeostasis; Temperature; Terminally Ill; Th1 Cells; Thiamethoxam; Thiazoles; Thiophenes; Thioredoxin Reductase 1; Thrombosis; Thulium; Thyroid Cancer, Papillary; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Time Factors; Titanium; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; TOR Serine-Threonine Kinases; Transcription Factor AP-1; Transcription Factors; Transcription, Genetic; Transcriptional Activation; Transcriptome; Transforming Growth Factor beta1; Transistors, Electronic; Translational Research, Biomedical; Transplantation Tolerance; Transplantation, Homologous; Transportation; Treatment Outcome; Tretinoin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Tubulin Modulators; Tumor Microenvironment; Tumor Necrosis Factor Inhibitors; Tumor Necrosis Factor-alpha; Twins; Ultrasonic Therapy; Ultrasonography; Ultraviolet Rays; United States; Up-Regulation; Uranium; Urethra; Urinary Bladder; Urodynamics; Uromodulin; Uveitis; Vasoconstrictor Agents; Ventricular Function, Left; Vero Cells; Vesicular Transport Proteins; Viral Nonstructural Proteins; Visual Acuity; Vital Capacity; Vitamin D; Vitamin D Deficiency; Vitamin K 2; Vitamins; Volatilization; Voriconazole; Waiting Lists; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical; Whole Genome Sequencing; Wine; Wnt Signaling Pathway; Wound Healing; Wounds and Injuries; WW Domains; X-linked Nuclear Protein; X-Ray Diffraction; Xanthines; Xenograft Model Antitumor Assays; YAP-Signaling Proteins; Yogurt; Young Adult; Zebrafish; Zebrafish Proteins; Ziziphus | 2016 |
Overcoming resistance to rapalogs in gliomas by combinatory therapies.
Glioblastoma is the most common and aggressive brain tumor type, with a mean patient survival of approximately 1year. Many previous analyses of the glioma kinome have identified key deregulated pathways that converge and activate mammalian target of rapamycin (mTOR). Following the identification and characterization of mTOR-promoting activity in gliomagenesis, data from preclinical studies suggested the targeting of mTOR by rapamycin or its analogs (rapalogs) as a promising therapeutic approach. However, clinical trials with rapalogs have shown very limited efficacy on glioma due to the development of resistance mechanisms. Analysis of rapalog-insensitive glioma cells has revealed increased activity of growth and survival pathways compensating for mTOR inhibition by rapalogs that are suitable for therapeutic intervention. In addition, recently developed mTOR inhibitors show high anti-glioma activity. In this review, we recapitulate the regulation of mTOR signaling and its involvement in gliomagenesis, discuss mechanisms resulting in resistance to rapalogs, and speculate on strategies to overcome resistance. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases (2012). Topics: Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Clinical Trials as Topic; Drug Resistance, Neoplasm; Glioma; Humans; Protein Kinase Inhibitors; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases | 2013 |
[Molecular targeted therapy for malignant brain tumors].
Topics: Antineoplastic Agents; Benzamides; Brain Neoplasms; Drug Delivery Systems; Drug Design; Drug Resistance, Neoplasm; Drug Therapy, Combination; ErbB Receptors; Erlotinib Hydrochloride; Gefitinib; Glioma; Humans; Imatinib Mesylate; Intracellular Signaling Peptides and Proteins; Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Piperazines; Piperidines; Protein Kinases; Protein-Tyrosine Kinases; Pyridines; Pyrimidines; Quinazolines; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases | 2005 |
11 trial(s) available for sirolimus and Glioma
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A phase II study of continuous oral mTOR inhibitor everolimus for recurrent, radiographic-progressive neurofibromatosis type 1-associated pediatric low-grade glioma: a Neurofibromatosis Clinical Trials Consortium study.
Activation of the mammalian target of rapamycin (mTOR) pathway is observed in neurofibromatosis type 1 (NF1) associated low-grade gliomas (LGGs), but agents that inhibit this pathway, including mTOR inhibitors, have not been studied in this population. We evaluate the efficacy of the orally administered mTOR inhibitor everolimus for radiographically progressive NF1-associated pediatric LGGs.. Children with radiologic-progressive, NF1-associated LGG and prior treatment with a carboplatin-containing chemotherapy were prospectively enrolled on this phase II clinical trial to receive daily everolimus. Whole blood was analyzed for everolimus and markers of phosphatidylinositol-3 kinase (PI3K)/mTOR pathway inhibition. Serial MRIs were obtained during treatment. The primary endpoint was progression-free survival at 48 weeks.. Twenty-three participants (median age, 9.4 y; range, 3.2-21.6 y) were enrolled. All participants were initially evaluable for response; 1 patient was removed from study after development of a malignant peripheral nerve sheath tumor. Fifteen of 22 participants (68%) demonstrated a response, defined as either shrinkage (1 complete response, 2 partial response) or arrest of tumor growth (12 stable disease). Of these, 10/15 remained free of progression (median follow-up, 33 mo). All remaining 22 participants were alive at completion of therapy. Treatment was well tolerated; no patient discontinued therapy due to toxicity. Pharmacokinetic parameters and pre-dose concentrations showed substantial between-subject variability. PI3K/mTOR pathway inhibition markers demonstrating blood mononuclear cell mTOR pathway inactivation was achieved in most participants.. Individuals with recurrent/progressive NF1-associated LGG demonstrate significant disease stability/shrinkage during treatment with oral everolimus with a well-tolerated toxicity profile. Everolimus is well suited for future consideration as upfront or combination therapy in this patient population. Topics: Antineoplastic Agents; Child; Everolimus; Glioma; Humans; Neurofibromatosis 1; Sirolimus; TOR Serine-Threonine Kinases | 2020 |
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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Pneumonia; Pneumonia, Viral; Point-of-Care Testing; Polyethylene Glycols; Polymers; Polysorbates; Pore Forming Cytotoxic Proteins; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Postprandial Period; Poverty; Pre-Exposure Prophylaxis; Prediabetic State; Predictive Value of Tests; Pregnancy; Pregnancy Trimester, First; Pregnancy, High-Risk; Prenatal Exposure Delayed Effects; Pressure; Prevalence; Primary Graft Dysfunction; Primary Health Care; Professional Role; Professionalism; Prognosis; Progression-Free Survival; Prolactin; Promoter Regions, Genetic; Proof of Concept Study; Proportional Hazards Models; Propylene Glycol; Prospective Studies; Prostate; Protein Binding; Protein Biosynthesis; Protein Isoforms; Protein Kinase Inhibitors; Protein Phosphatase 2; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases; Protein Structure, Tertiary; Protein Transport; Proteoglycans; Proteome; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-myc; 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STAT3 Transcription Factor; Streptomyces coelicolor; Stress, Psychological; Stroke; Stroke Volume; Structure-Activity Relationship; Students, Medical; Students, Pharmacy; Substance Abuse Treatment Centers; Sulfur Dioxide; Surface Properties; Surface-Active Agents; Surveys and Questionnaires; Survival Analysis; Survival Rate; Survivin; Sweden; Swine; Swine, Miniature; Sympathetic Nervous System; T-Lymphocytes, Regulatory; Talaromyces; Tandem Mass Spectrometry; tau Proteins; Telemedicine; Telomerase; Telomere; Telomere Homeostasis; Temperature; Terminally Ill; Th1 Cells; Thiamethoxam; Thiazoles; Thiophenes; Thioredoxin Reductase 1; Thrombosis; Thulium; Thyroid Cancer, Papillary; Thyroid Carcinoma, Anaplastic; Thyroid Neoplasms; Time Factors; Titanium; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; TOR Serine-Threonine Kinases; Transcription Factor AP-1; Transcription Factors; Transcription, Genetic; Transcriptional Activation; Transcriptome; Transforming Growth Factor beta1; Transistors, Electronic; Translational Research, Biomedical; Transplantation Tolerance; Transplantation, Homologous; Transportation; Treatment Outcome; Tretinoin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Tubulin Modulators; Tumor Microenvironment; Tumor Necrosis Factor Inhibitors; Tumor Necrosis Factor-alpha; Twins; Ultrasonic Therapy; Ultrasonography; Ultraviolet Rays; United States; Up-Regulation; Uranium; Urethra; Urinary Bladder; Urodynamics; Uromodulin; Uveitis; Vasoconstrictor Agents; Ventricular Function, Left; Vero Cells; Vesicular Transport Proteins; Viral Nonstructural Proteins; Visual Acuity; Vital Capacity; Vitamin D; Vitamin D Deficiency; Vitamin K 2; Vitamins; Volatilization; Voriconazole; Waiting Lists; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical; Whole Genome Sequencing; Wine; Wnt Signaling Pathway; Wound Healing; Wounds and Injuries; WW Domains; X-linked Nuclear Protein; X-Ray Diffraction; Xanthines; Xenograft Model Antitumor Assays; YAP-Signaling Proteins; Yogurt; Young Adult; Zebrafish; Zebrafish Proteins; Ziziphus | 2016 |
Phase I/II study of erlotinib and temsirolimus for patients with recurrent malignant gliomas: North American Brain Tumor Consortium trial 04-02.
Inhibition of epidermal growth factor receptor (EGFR) and the mechanistic target of rapamycin (mTOR) may have synergistic antitumor effects in high-grade glioma patients.. We conducted a phase I/II study of the EGFR inhibitor erlotinib (150 mg/day) and the mTOR inhibitor temsirolimus. Patients initially received temsirolimus 50 mg weekly, and the dose adjusted based on toxicities. In the phase II component, the primary endpoint was 6-month progression-free survival (PFS6) among glioblastoma patients.. Twenty-two patients enrolled in phase I, 47 in phase II. Twelve phase I patients treated at the maximum tolerated dosage were included in the phase II cohort for analysis. The maximum tolerated dosage was 15 mg temsirolimus weekly with erlotinib 150 mg daily. Dose-limiting toxicities were rash and mucositis. Among 42 evaluable glioblastoma patients, 12 (29%) achieved stable disease, but there were no responses, and PFS6 was 13%. Among 16 anaplastic glioma patients, 1 (6%) achieved complete response, 1 (6%) partial response, and 2 (12.5%) stable disease, with PFS6 of 8%. Tumor levels of both drugs were low, and posttreatment tissue in 3 patients showed no reduction in the mTOR target phosphorylated (phospho-)S6(S235/236) but possible compensatory increase in phospho-Akt(S473). Presence of EGFR variant III, phospho-EGFR, and EGFR amplification did not correlate with survival, but patients with elevated phospho-extracellular signal-regulated kinase or reduced phosphatase and tensin homolog protein expression had decreased progression-free survival at 4 months.. Because of increased toxicity, the maximum tolerated dosage of temsirolimus in combination with erlotinib proved lower than expected. Insufficient tumor drug levels and redundant signaling pathways may partly explain the minimal antitumor activity noted. Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Erlotinib Hydrochloride; Female; Follow-Up Studies; Glioma; Humans; Male; Middle Aged; Neoplasm Recurrence, Local; Neoplasm Staging; Prognosis; Quinazolines; Sirolimus; Survival Rate; Tissue Distribution; Young Adult | 2014 |
A feasibility and efficacy study of rapamycin and erlotinib for recurrent pediatric low-grade glioma (LGG).
To determine the toxicity and efficacy of rapamycin and erlotinib for the treatment of recurrent pediatric low-grade gliomas (LGGs).. Patients <21 years of age with recurrent LGGs who had failed conventional treatment were eligible, including those with NF1. The treatment consisted of two phases, a feasibility portion which assessed the toxicity of erlotinib at 65 mg/m(2) /day once daily and rapamycin at 0.8 mg/m(2) /dose twice daily for 28 consecutive days.. Nineteen (19) patients, median age of 8 years, with recurrent LGGs received the two-drug regimen. Eight (8) of the patients had NF1. The combination of erlotinib and rapamycin was well tolerated and no patient was removed from study due to toxicity. All 19 patients were evaluable for response and one child, with NF1, had a partial response to treatment. Six (6) patients received the planned 12 courses of treatment. The reasons for stoppage of therapy before 1 year of treatment were poor compliance (1), parental desire for withdrawal (1), persistent vomiting which pre-dated initiation of therapy (1), and radiographic progression (10). In those patients with stabilization of disease for 12 months or greater, 3 stayed on therapy and ultimately developed progressive disease, and one patient stopped therapy at 12 months and progressed. Two (2) patients, both with NF1, have had >1 year disease control.. The combination of rapamycin and erlotinib is well tolerated in children with LGGs. Objective responses were infrequent, although there was prolonged disease stabilization in some patients with LGGs, especially in two children with NF1. Topics: Adolescent; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Child; Child, Preschool; ErbB Receptors; Erlotinib Hydrochloride; Feasibility Studies; Female; Glioma; Humans; Male; Neoplasm Recurrence, Local; Quinazolines; Sirolimus; TOR Serine-Threonine Kinases | 2013 |
Phase II trial of temsirolimus in children with high-grade glioma, neuroblastoma and rhabdomyosarcoma.
A phase II study of temsirolimus was conducted in children and adolescents with high-grade glioma, neuroblastoma or rhabdomyosarcoma.. Temsirolimus 75 mg/m(2) was administered once weekly until disease progression or intolerance. Using the Simon 2-stage design, further enrolment in each disease cohort required ≥ 2 objective responses within the first 12 weeks for the first 12 evaluable patients (those who received ≥ 3 temsirolimus doses).. Fifty-two heavily pretreated patients with relapsed (12%) or refractory (88%) disease, median age 8 years (range 1-21 years), were enroled and treated. One patient with neuroblastoma achieved confirmed partial response within the first 12 weeks; thus, none of the 3 cohorts met the criterion for continued enrolment. Disease stabilisation at week 12 was observed in 7 of 17 patients (41%) with high-grade glioma (5 diffuse pontine gliomas, 1 glioblastoma multiforme and 1 anaplastic astrocytoma), 6 of 19 (32%) with neuroblastoma and 1 of 16 (6%) with rhabdomyosarcoma (partial response confirmed at week 18). In the three cohorts, median duration of stable disease or better was 128, 663 and 75 d, respectively. The most common treatment-related adverse events were thrombocytopaenia, hyperlipidaemia and aesthenia. Pharmacokinetic findings were similar to those observed in adults.. Temsirolimus administered weekly at the dose of 75 mg/m(2) did not meet the primary objective efficacy threshold in children with high-grade glioma, neuroblastoma or rhabdomyosarcoma; however, meaningful prolonged stable disease merits further evaluation in combination therapy. Topics: Adolescent; Adult; Antineoplastic Agents; Brain Neoplasms; Child; Child, Preschool; Cohort Studies; Disease Progression; Female; Glioma; Humans; Infusions, Intravenous; Male; Neuroblastoma; Rhabdomyosarcoma; Sirolimus | 2012 |
Ridaforolimus for patients with progressive or recurrent malignant glioma: a perisurgical, sequential, ascending-dose trial.
This perisurgical phase 1 study evaluated the pharmacokinetics, pharmacodynamics, and safety of the mammalian target of rapamycin (mTOR) inhibitor ridaforolimus in patients (N = 10) with progressive or recurrent primary grade IV malignant glioma, who failed standard therapy. The primary objective of the study was to determine the maximum tolerated dose (MTD) of ridaforolimus.. Treatment was administered intravenously at doses of 12.5 mg (N = 7) or 15 mg (N = 3) once daily for 4 days prior to surgical resection, then resumed for 5 consecutive days every 2 weeks until disease progression or unacceptable toxicity, following a postsurgical recovery period.. The MTD was not determined because the trial was suspended early due to slower than expected patient accrual and postsurgical drug administration challenges. Pharmacokinetic and pharmacodynamic analyses showed that ridaforolimus concentrations declined slowly during the 24-h dosing interval and remained detectable for 10 days after the last infusion in whole blood samples. In peripheral blood mononuclear cells, median levels of the mTOR downstream effector p4E-BP1 were reduced by >80% compared with baseline by 4 h after dosing. Resected brain specimens showed reduced levels of pS6, another mTOR downstream effector, while nuclear staining for p27(kip1), a protein that functions as a cell cycle inhibitor, increased after treatment. No dose-limiting toxicities were observed, and the reported adverse events were consistent with the previously established safety profile for ridaforolimus. One of 3 patients evaluable for efficacy had stable disease as best response.. Results suggest that ridaforolimus can cross the blood-brain barrier in areas of tumor involvement, and may inhibit mTOR activity in advanced gliomas based on decreased pS6 levels. This perisurgical trial design should serve as a template for evaluating intratumoral pharmacokinetics and pharmacodynamics of other targeted agents in this patient population. Topics: Adult; Aged; Antibiotics, Antineoplastic; Cohort Studies; Combined Modality Therapy; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Glioma; Humans; Immunohistochemistry; Male; Maximum Tolerated Dose; Middle Aged; Sirolimus | 2012 |
A dose escalation trial for the combination of erlotinib and sirolimus for recurrent malignant gliomas.
In order to achieve higher dosages than previously used in clinical trials, we conducted a phase I trial to determine the maximum tolerated dose (MTD) for the combination of erlotinib and sirolimus for the treatments of recurrent malignant gliomas. Patients with pathologically proven World Health Organization (WHO) grade III glioma and grade IV glioblastoma and radiographically proven tumor recurrence were eligible for this study. Treatments included once daily erlotinib, which was given alone for the first 7 days of treatments, then in combination with once daily sirolimus. Sirolimus was given with a loading dose on day 8 followed by a maintenance dose starting on day 9. Dose-limiting toxicity (DLT) was determined over the first 28 days of treatments, and the MTD was determined in a 3 + 3 classic study design. 19 patients were enrolled, and 13 patients were eligible for MTD determination. The MTD was determined to be 150 mg daily for erlotinib and 5 mg daily (after a 15 mg loading dose) for sirolimus. The DLTs included rash and mucositis (despite maximal medical managements), hypophosphatemia, altered mental status, and neutropenia. The combination of erlotinib and sirolimus is difficult to tolerate at dosages higher than previously reported in phase II trials. Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Dose-Response Relationship, Drug; Erlotinib Hydrochloride; Feasibility Studies; Female; Glioma; Humans; Male; Middle Aged; Neoplasm Recurrence, Local; Prognosis; Quinazolines; Retrospective Studies; Sirolimus; Survival Rate; Tissue Distribution | 2012 |
Pharmacokinetic profile of temsirolimus with concomitant administration of cytochrome p450-inducing medications.
Temsirolimus is a novel inhibitor of the mammalian target of rapamycin, with antitumor activity in advanced tumors. Because temsirolimus and its metabolite, sirolimus, are cytochrome P450 (CYP) 3A4/5 substrates, the potential exists for interaction with drugs that induce CYP3A activity, including enzyme inducers and rifampin. Cancer patients received once-weekly intravenous (IV) 220 mg/m(2) temsirolimus with or without enzyme inducers. Coadministration with enzyme inducers decreased temsirolimus maximum plasma concentration (C(max)) by 36% and increased volume of distribution by 99%. Sirolimus C(max) and area under the concentration-time curve (AUC) were decreased by 67% and 43%, respectively. In healthy adult subjects, coadministration of 25-mg intravenous temsirolimus with rifampin had no significant effect on temsirolimus C(max) and AUC but decreased sirolimus C(max) and AUC by 65% and 56%, respectively. Rifampin decreased AUC(sum) by 41%. Temsirolimus was well tolerated in both studies. If concomitant agents with CYP3A induction potential are used, higher temsirolimus doses may be needed to achieve adequate tumor tissue drug levels. Topics: Adolescent; Adult; Aged; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Enzyme Induction; Female; Glioma; Humans; Male; Middle Aged; Protein Kinase Inhibitors; Protein Kinases; Rifampin; Sirolimus; TOR Serine-Threonine Kinases | 2007 |
Pharmacokinetic and tumor distribution characteristics of temsirolimus in patients with recurrent malignant glioma.
To characterize the pharmacokinetics of temsirolimus and its major metabolite, sirolimus, in patients receiving enzyme-inducing antiepileptic drugs (EIAED) compared with patients receiving non-EIAEDs. An additional objective was to determine whether concentrations of temsirolimus or sirolimus were achieved in brain tumor tissue.. Patients with recurrent malignant gliomas not receiving EIAEDs initially received temsirolimus weekly at a dose of 250 mg i.v. The dose was subsequently reduced to 170 mg due to intolerable side effects. For patients taking EIAEDs, the starting dose of temsirolimus was 250 mg with standard dose escalation until the maximal tolerated dose was established. Ten whole blood samples were obtained over a period of 24 h after administration of temsirolimus for pharmacokinetic assessments. Patients eligible for cytoreductive surgery received temsirolimus before tumor resection. Whole blood and tumor tissue were obtained for analysis.. Significant differences in the pharmacokinetic variables for temsirolimus and sirolimus were observed between the two patient groups at a comparable dose level of 250 mg. For patients receiving EIAEDs, the systemic exposure to temsirolimus was lower by 1.5-fold. Likewise, peak concentrations and exposure to sirolimus were lower by 2-fold. Measurable concentrations of temsirolimus and sirolimus were observed in brain tumor specimens. The average tissue to whole blood ratio for temsirolimus was 1.43 and 0.84 for sirolimus.. Drugs that induce cytochrome P450 3A4, such as EIAEDs, significantly affect the pharmacokinetics of temsirolimus and its active metabolite, sirolimus. Total exposure to temsirolimus and sirolimus was lower in the EIAED group at the maximum tolerated dose of 250 mg compared with the non-EIAED group at the maximum tolerated dose of 170 mg. However, brain tumor tissue concentrations of temsirolimus and sirolimus were relatively comparable in both groups of patients at their respective dose levels. Correlative analyses of the tissue for the inhibition of the key regulators (p70S6 kinase and 4E-binding protein 1) of mammalian target of rapamycin are necessary to define the therapeutic significance of the altered exposure to temsirolimus. Topics: Anticonvulsants; Antineoplastic Agents; Area Under Curve; Brain Neoplasms; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Drug Interactions; Glioma; Humans; Maximum Tolerated Dose; Metabolic Clearance Rate; Neoplasm Recurrence, Local; Sirolimus | 2007 |
Phase 1 trial of gefitinib plus sirolimus in adults with recurrent malignant glioma.
To determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of gefitinib, a receptor tyrosine kinase inhibitor of the epidermal growth factor receptor, plus sirolimus, an inhibitor of the mammalian target of rapamycin, among patients with recurrent malignant glioma.. Gefitinib and sirolimus were administered on a continuous daily dosing schedule at dose levels that were escalated in successive cohorts of malignant glioma patients at any recurrence who were stratified based on concurrent use of CYP3A-inducing anticonvulsants [enzyme-inducing antiepileptic drugs, (EIAED)]. Pharmacokinetic and archival tumor biomarker data were also assessed.. Thirty-four patients with progressive disease after prior radiation therapy and chemotherapy were enrolled, including 29 (85%) with glioblastoma multiforme and 5 (15%) with anaplastic glioma. The MTD was 500 mg of gefitinib plus 5 mg of sirolimus for patients not on EIAEDs and 1,000 mg of gefitinib plus 10 mg of sirolimus for patients on EIAEDs. DLTs included mucositis, diarrhea, rash, thrombocytopenia, and hypertriglyceridemia. Gefitinib exposure was not affected by sirolimus administration but was significantly lowered by concurrent EIAED use. Two patients (6%) achieved a partial radiographic response, and 13 patients (38%) achieved stable disease.. We show that gefitinib plus sirolimus can be safely coadministered on a continuous, daily dosing schedule, and established the recommended dose level of these agents in combination for future phase 2 clinical trials. Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Gefitinib; Glioma; Humans; Male; Middle Aged; Quinazolines; Recurrence; Sirolimus; Treatment Outcome | 2006 |
Phase I/pharmacokinetic study of CCI-779 in patients with recurrent malignant glioma on enzyme-inducing antiepileptic drugs.
CCI-779 is an ester of the immunosuppressive agent sirolimus (rapamycin) that causes cell-cycle arrest at G1 via inhibition of key signaling pathways resulting in inhibition of RNA translation. Antitumor activity has been demonstrated using cell lines and animal models of malignant glioma. Patients receiving enzyme-inducing anti-epileptic drugs (EIAEDs) can have altered metabolism of drugs like CCI-779 that are metabolized through the hepatic cytochrome P450 enzyme system. The objectives of this study were to determine the pharmacokinetic profile and the maximum tolerated dose of CCI-779 in patients with recurrent malignant gliioma taking EIAEDs.. The starting dose of CCI-779 was 250 mg intravenously (IV) administered weekly on a continuous basis. Standard dose escalation was performed until the maximum tolerated dose was established. Toxicity was assessed using the National Cancer Institute common toxicity criteria.. Two of 6 patients treated at the second dose level of 330 mg sustained a dose-limiting toxicity: grade III stomatitis, grade 3 hypercholesterolemia, or grade 4 hypertriglyceridemia. The maximum tolerated dose was reached at 250 mg IV. Pharmacokinetic profiles were similar to those previously described, but the area under the whole blood concentration-time curve of rapamycin was 1.6 fold lower for patients on EIAEDs.. The recommended phase II dose of CCI 779 for patients on enzyme-inducing antiepileptic drugs is 250 mg IV weekly. A phase II study is ongoing to determine the efficacy of this agent. Topics: Adult; Anticonvulsants; Antineoplastic Agents; Brain Neoplasms; Cohort Studies; Cytochrome P-450 Enzyme System; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Interactions; Enzyme Induction; Female; Glioma; Humans; Infusions, Intravenous; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Recurrence, Local; Sirolimus; Treatment Outcome | 2004 |
55 other study(ies) available for sirolimus and Glioma
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mTOR Inhibition Is Effective against Growth, Survival and Migration, but Not against Microglia Activation in Preclinical Glioma Models.
Initially introduced in therapy as immunosuppressants, the selective inhibitors of mTORC1 have been approved for the treatment of solid tumors. Novel non-selective inhibitors of mTOR are currently under preclinical and clinical developments in oncology, attempting to overcome some limitations associated with selective inhibitors, such as the development of tumor resistance. Looking at the possible clinical exploitation in the treatment of glioblastoma multiforme, in this study we used the human glioblastoma cell lines U87MG, T98G and microglia (CHME-5) to compare the effects of a non-selective mTOR inhibitor, sapanisertib, with those of rapamycin in a large array of experimental paradigms, including (i) the expression of factors involved in the mTOR signaling cascade, (ii) cell viability and mortality, (iii) cell migration and autophagy, and (iv) the profile of activation in tumor-associated microglia. We could distinguish between effects of the two compounds that were overlapping or similar, although with differences in potency and or/time-course, and effects that were diverging or even opposite. Among the latter, especially relevant is the difference in the profile of microglia activation, with rapamycin being an overall inhibitor of microglia activation, whereas sapanisertib was found to induce an M2-profile, which is usually associated with poor clinical outcomes. Topics: Cell Line, Tumor; Cell Proliferation; Glioblastoma; Glioma; Humans; Mechanistic Target of Rapamycin Complex 1; Microglia; Sirolimus; TOR Serine-Threonine Kinases | 2023 |
Inhibition of autophagy and induction of glioblastoma cell death by NEO214, a perillyl alcohol-rolipram conjugate.
Topics: Autophagy; Cell Death; Chloroquine; Glioblastoma; Glioma; Humans; Lysosomes; Monoterpenes; Rolipram; Sirolimus; Temozolomide; TOR Serine-Threonine Kinases | 2023 |
Regulation of TORC1 by MAPK Signaling Determines Sensitivity and Acquired Resistance to Trametinib in Pediatric BRAFV600E Brain Tumor Models.
We investigated why three patient-derived xenograft (PDX) childhood BRAFV600E-mutant brain tumor models are highly sensitive to trametinib. Mechanisms of acquired resistance selected in situ, and approaches to prevent resistance were also examined, which may translate to both low-grade glioma (LGG) molecular subtypes.. Sensitivity to trametinib [MEK inhibitor (MEKi)] alone or in combination with rapamycin (TORC1 inhibitor), was evaluated in pediatric PDX models. The effect of combined treatment of trametinib with rapamycin on development of trametinib resistance in vivo was examined. PDX tissue and tumor cells from trametinib-resistant xenografts were characterized.. In pediatric models TORC1 is activated through ERK-mediated inactivation of the tuberous sclerosis complex (TSC): consequently inhibition of MEK also suppressed TORC1 signaling. Trametinib-induced tumor regression correlated with dual inhibition of MAPK/TORC1 signaling, and decoupling TORC1 regulation from BRAF/MAPK control conferred trametinib resistance. In mice, acquired resistance to trametinib developed within three cycles of therapy in all three PDX models. Resistance to trametinib developed in situ is tumor-cell-intrinsic and the mechanism was tumor line specific. Rapamycin retarded or blocked development of resistance.. In these three pediatric BRAF-mutant brain tumors, TORC1 signaling is controlled by the MAPK cascade. Trametinib suppressed both MAPK/TORC1 pathways leading to tumor regression. While low-dose intermittent rapamycin to enhance inhibition of TORC1 only modestly enhanced the antitumor activity of trametinib, it prevented or retarded development of trametinib resistance, suggesting future therapeutic approaches using rapamycin analogs in combination with MEKis that may be therapeutically beneficial in both KIAA1549::BRAF- and BRAFV600E-driven gliomas. Topics: Animals; Brain Neoplasms; Cell Line, Tumor; Disease Models, Animal; Glioma; Humans; Mechanistic Target of Rapamycin Complex 1; Mice; Mitogen-Activated Protein Kinase Kinases; Mutation; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Pyridones; Pyrimidinones; Sirolimus | 2022 |
Case Report: Reversible Hyperglycemia Following Rapamycin Treatment for Atypical Choroid Plexus Papilloma in an Infant.
In this study, atypical choroid plexus papilloma was treated with high-dose rapamycin for 17 days preoperatively in an infant. Rapamycin significantly reduced the blood supply to the tumor while reducing the tumor volume, and most of the tumor was resected successfully. However, the infant developed hyperglycemia related to the rapamycin dose, which was effectively controlled by adjusting the dose and applying insulin. Topics: Choroid Plexus Neoplasms; Glioma; Humans; Hyperglycemia; Infant; Papilloma, Choroid Plexus; Sirolimus | 2022 |
Gambogic Acid Affects Ribosomal Occurrence in Glioma Cells by Downregulating the Phosphoinositide Kinase-3/Protein Kinase B/Mammalian Target of Rapamycin Signaling Pathway.
Gambogic acid (GA) is a natural compound with a polyprenylated xanthone structure that has antiinflammatory, antioxidant, and neuroprotective properties and acts as a chemopreventive agent. GA exhibits anti-tumor, antimicrobial, and anti-proliferative effects on cancer cells. In the current study, the effect of GA on phosphoinositide kinase-3 (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway was examined in human U251 glioma cells. Cell viability and apoptosis were evaluated by MTT and Annexin V/PI Double Staining. The expressions of P38, AKT, and mTOR were evaluated by western blot and qRT-PCR, respectively. MagBeads Total RNA Extraction Kit was used to isolate cell tissue RNA. GA decreased the phosphorylation of P38, AKT, and mTOR. Inhibitors of PI3K (LY294002) enhanced the phosphorylation of P38, AKT, and mTOR. GA reduced the phosphorylation of ribosomal protein precursors (Pre) and upstream binding factor (UBF), and insulin-like growth factor I (IGF-1) further enhanced the cell proliferation and expression of Pre and UBF. These results suggested that downregulation of PI3K/AKT/mTOR signaling pathway may be an important mediator in GA-affected ribosomal occurrence in glioma cells. Topics: 1-Phosphatidylinositol 4-Kinase; Apoptosis; Cell Proliferation; Glioma; Humans; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Xanthones | 2020 |
Synergistic Combination of Oncolytic Virotherapy and Immunotherapy for Glioma.
We hypothesized that the combination of a local stimulus for activating tumor-specific T cells and an anti-immunosuppressant would improve treatment of gliomas. Virally encoded IL15Rα-IL15 as the T-cell activating stimulus and a prostaglandin synthesis inhibitor as the anti-immunosuppressant were combined with adoptive transfer of tumor-specific T cells.. vvDD-IL15Rα-YFP and vMyx-IL15Rα-tdTr each infected and killed GL261 cells. IL15Rα-IL15-armed oncolytic poxviruses provide potent antitumor effects against brain tumors when combined with adoptive T-cell therapy, rapamycin, and celecoxib. Topics: Animals; Brain Neoplasms; Celecoxib; Cell Line, Tumor; Combined Modality Therapy; Cyclooxygenase 2 Inhibitors; Disease Models, Animal; Drug Synergism; Female; Glioma; Immunosuppressive Agents; Immunotherapy; Immunotherapy, Adoptive; Interleukin-15; Male; Mice, Inbred C57BL; Myxoma virus; Oncolytic Virotherapy; Receptors, Interleukin-15; Sirolimus; Vaccinia virus | 2020 |
Second Generation mTOR Inhibitors as a Double-Edged Sword in Malignant Glioma Treatment.
Glioblastomas (GBs) frequently display activation of the epidermal growth factor receptor (EGFR) and mammalian target of rapamycin (mTOR). mTOR exists as part of two multiprotein complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2). In GBs, mTORC1 inhibitors such as rapamycin have performed poorly in clinical trials, and in vitro protect GB cells from nutrient and oxygen deprivation. Next generation ATP-competitive mTOR inhibitors with affinity for both mTOR complexes have been developed, but data exploring their effects on GB metabolism are scarce. In this study, we compared the ATP-competitive mTORC1/2 inhibitors torin2, INK-128 and NVP-Bez235 to the allosteric mTORC1 inhibitor rapamycin under conditions that mimic the glioma microenvironment. In addition to inhibiting mTORC2 signaling, INK-128 and NVP-Bez235 more effectively blocked mTORC1 signaling and prompted a stronger cell growth inhibition, partly by inducing cell cycle arrest. However, under hypoxic and nutrient-poor conditions mTORC1/2 inhibitors displayed even stronger cytoprotective effects than rapamycin by reducing oxygen and glucose consumption. Thus, therapies that arrest proliferation and inhibit anabolic metabolism must be expected to improve energy homeostasis of tumor cells. These results mandate caution when treating physiologically or therapeutically induced hypoxic GBs with mTOR inhibitors. Topics: Apoptosis; Benzoxazoles; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Glioma; Humans; Imidazoles; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Naphthyridines; Protein Kinase Inhibitors; Pyrimidines; Quinolines; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases | 2019 |
Malignant gliomas can be converted to non‑proliferating glial cells by treatment with a combination of small molecules.
Gliomas, the most highly malignant central nervous system tumors, are associated with an extremely poor patient survival rate. Given that gliomas are derived from mutations in glial precursor cells, a considerable number of them strongly react with glial precursor cell‑specific markers. Thus, we investigated whether malignant gliomas can be converted to glial cells through the regulation of endogenous gene expression implicated in glial precursor cells. In the present study, we used three small‑molecule compounds, [cyclic adenosine monophosphate (cAMP) enhancer, a mammalian target of rapamycin (mTOR) inhibitor, and a bromodomain and extra‑terminal motif (BET) inhibitor] for glial reprogramming. Small‑molecule‑induced gliomas (SMiGs) were not only transformed into exhibiting a glial‑specific morphology, but also showed positive reactions with glial‑specific markers such as glial fibrillary acidic protein (GFAP), 2',3'‑cyclic nucleotide 3'‑phosphohydrolase (CNP) and anti‑oligodendrocyte (RIP). A microarray analysis indicated that SMiGs exhibited a marked increase in specific gene levels, whereas that of a malignant cancer‑specific gene was greatly decreased. Moreover, proliferation of the cells was markedly suppressed after the conversion of malignant glioma cells into glial cells. Our findings confirmed that malignant gliomas can be reprogrammed to non‑proliferating glial cells, using a combination of small molecules, and their proliferation can be regulated by their differentiation. We suggest that our small‑molecule combination (with forskolin, rapamycin and I‑BET151) may be the next generation of anticancer agents that act by reprogramming malignant gliomas to differentiate into glial cells. Topics: 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase; Animals; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cellular Reprogramming; Colforsin; Drug Therapy, Combination; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Glial Fibrillary Acidic Protein; Glioma; Heterocyclic Compounds, 4 or More Rings; Humans; Neuroglia; Oligonucleotide Array Sequence Analysis; Rats; Sirolimus; Small Molecule Libraries | 2019 |
MIR93 (microRNA -93) regulates tumorigenicity and therapy response of glioblastoma by targeting autophagy.
Macroautophagy/autophagy is a natural intracellular process that maintains cellular homeostasis and protects cells from death under stress conditions. Autophagy sustains tumor survival and growth when induced by common cancer treatments, including IR and cytotoxic chemotherapy, thereby contributing to therapeutic resistance of tumors. In this study, we report that the expression of MIR93, noted in two clinically relevant tumor subtypes of GBM, influenced GSC phenotype as well as tumor response to therapy through its effects on autophagy. Our mechanistic studies revealed that MIR93 regulated autophagic activities in GSCs through simultaneous inhibition of multiple autophagy regulators, including BECN1/Beclin 1, ATG5, ATG4B, and SQSTM1/p62. Moreover, two first-line treatments for GBM, IR and temozolomide (TMZ), as well as rapamycin (Rap), the prototypic MTOR inhibitor, decreased MIR93 expression that, in turn, stimulated autophagic processes in GSCs. Inhibition of autophagy by ectopic MIR93 expression, or via autophagy inhibitors NSC (an ATG4B inhibitor) and CQ, enhanced the activity of IR and TMZ against GSCs. Collectively, our findings reveal a key role for MIR93 in the regulation of autophagy and suggest a combination treatment strategy involving the inhibition of autophagy while administering cytotoxic therapy. Abbreviations: ACTB: actin beta; ATG4B: autophagy related 4B cysteine peptidase; ATG5: autophagy related 5; BECN1: beclin 1; CL: classical; CQ: chloroquine diphosphate; CSCs: cancer stem cells; GBM: glioblastoma; GSCs: glioma stem-like cells; HEK: human embryonic kidney; IB: immunoblotting; IF: immunofluorescent staining; IR: irradiation; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MES: mesenchymal; MIR93: microRNA 93; MIRC: a control miRNA; miRNA/miR: microRNA; MTOR: mechanistic target of rapamycin kinase; NSC: NSC185085; PN: proneural; qRT-PCR: quantitative reverse transcription-polymerase chain reaction; Rap: rapamycin; SQSTM1/p62: sequestosome 1; TCGA: the cancer genome atlas; TMZ: temozolomide; WT: wild type; ZIP93: lentiviral miRZIP targeting MIR93; ZIPC: lentiviral miRZip targeting control miRNA. Topics: Animals; Autophagy; Autophagy-Related Proteins; Glioma; HEK293 Cells; Humans; Mice, Nude; MicroRNAs; Neoplastic Stem Cells; Sirolimus; Temozolomide; Transplantation, Heterologous | 2019 |
Extracellular aggregated alpha synuclein primarily triggers lysosomal dysfunction in neural cells prevented by trehalose.
Cell-to-cell propagation of aggregated alpha synuclein (aSyn) has been suggested to play an important role in the progression of alpha synucleinopathies. A critical step for the propagation process is the accumulation of extracellular aSyn within recipient cells. Here, we investigated the trafficking of distinct exogenous aSyn forms and addressed the mechanisms influencing their accumulation in recipient cells. The aggregated aSyn species (oligomers and fibrils) exhibited more pronounced accumulation within recipient cells than aSyn monomers. In particular, internalized extracellular aSyn in the aggregated forms was able to seed the aggregation of endogenous aSyn. Following uptake, aSyn was detected along endosome-to-lysosome and autophagosome-to-lysosome routes. Intriguingly, aggregated aSyn resulted in lysosomal activity impairment, accompanied by the accumulation of dilated lysosomes. Moreover, analysis of autophagy-related protein markers suggested decreased autophagosome clearance. In contrast, the endocytic pathway, proteasome activity, and mitochondrial homeostasis were not substantially affected in recipient cells. Our data suggests that extracellularly added aggregated aSyn primarily impairs lysosomal activity, consequently leading to aSyn accumulation within recipient cells. Importantly, the autophagy inducer trehalose prevented lysosomal alterations and attenuated aSyn accumulation within aSyn-exposed cells. Our study underscores the importance of lysosomes for the propagation of aSyn pathology, thereby proposing these organelles as interventional targets. Topics: alpha-Synuclein; Animals; Autophagy; Cell Line, Tumor; Escherichia coli; Glioma; Humans; Lysosomes; Neurons; Parkinson Disease; Protein Aggregation, Pathological; Rats; Rats, Wistar; Recombinant Proteins; Sirolimus; Trehalose | 2019 |
Autophagy-induced KDR/VEGFR-2 activation promotes the formation of vasculogenic mimicry by glioma stem cells.
Antiangiogenesis with bevacizumab, an antibody against vascular endothelial growth factor (VEGF), has been used for devascularization to limit the growth of malignant glioma. However, the benefits are transient due to elusive mechanisms underlying resistance to the antiangiogenic therapy. Glioma stem cells (GSCs) are capable of forming vasculogenic mimicry (VM), an alternative microvascular circulation independent of VEGF-driven angiogenesis. Herein, we report that the formation of VM was promoted by bevacizumab-induced macroautophagy/autophagy in GSCs, which was associated with tumor resistance to antiangiogenic therapy. We established a 3-dimensional collagen scaffold to examine the formation of VM and autophagy by GSCs, and found that rapamycin increased the number of VM and enhanced KDR/VEGFR-2 phosphorylation. Treatment with chloroquine, or knockdown of the autophagy gene ATG5, inhibited the formation of VM and KDR phosphorylation in GSCs. Notably, neutralization of GSCs-produced VEGF with bevacizumab failed to recapitulate the effect of chloroquine treatment and ATG5 knockdown, suggesting that autophagy-promoted formation of VM was independent of tumor cell-derived VEGF. ROS was elevated when autophagy was induced in GSCs and activated KDR phosphorylation through the phosphoinositide 3-kinase (PI3K)-AKT pathway. A ROS inhibitor, N-acetylcysteine, abolished KDR phosphorylation and the formation of VM by GSCs. By examination of the specimens from 95 patients with glioblastoma, we found that ATG5 and p-KDR expression was strongly associated with the density of VM in tumors and poor clinical outcome. Our results thus demonstrate a crucial role of autophagy in the formation of VM by GSCs, which may serve as a therapeutic target in drug-resistant glioma. Topics: Animals; Autophagy; Autophagy-Related Protein 5; Bevacizumab; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Chloroquine; Female; Gene Knockdown Techniques; Glioma; Humans; Mice; Mice, SCID; Models, Biological; Neoplastic Stem Cells; Neovascularization, Pathologic; Phosphorylation; Reactive Oxygen Species; Sirolimus; Survival Analysis; Tissue Scaffolds; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2 | 2017 |
Multimodal Magnetic Resonance Imaging of Treatment-Induced Changes to Diffuse Infiltrating Pontine Gliomas in Children and Correlation to Patient Progression-Free Survival.
To use multimodal magnetic resonance imaging (MRI) to quantify treatment-induced changes in the whole volume of diffuse infiltrating pontine gliomas and correlate them with progression-free survival (PFS).. This prospective study included 22 children aged 3.3 to 14.7 years (median, 5.9 years). Multimodal MRI was performed at 3 distinct time points: before treatment, the first week following radiation therapy (RT), and 2 months after RT. The imaging protocol included morphologic, multi b-value diffusion; arterial spin labeling; and dynamic susceptibility contrast-enhanced perfusion. Morphologic and multimodal data-lesion volume, diffusion coefficients, relative cerebral blood flow, and relative cerebral blood volume (rCBV)-were recorded at the 3 aforementioned time points. The Wilcoxon test was used to compare each individual parameter variation between time points, and its correlation with PFS was assessed by the Spearman test.. Following RT, the tumors' solid component volume decreased by 40% (P<.001). Their median diffusion coefficients decreased by 20% to 40% (P<.001), while median relative cerebral blood flow increased by 60% to 80% (P<.001) and median rCBV increased by 70% (P<.001). PFS was positively correlated with rCBV measured immediately after RT (P=.003), and in patients whose rCBV was above the cutoff value of 2.46, the median PFS was 4.6 months longer (P=.001). These indexes tended to return to baseline 2 months after RT. Lesion volume before or after RT was not correlated with survival.. Multimodal MRI provides useful information about diffuse infiltrating pontine gliomas' response to treatment; rCBV increases following RT, and higher values are correlated with better PFS. High rCBV values following RT should not be mistaken for progression and could be an indicator of response to therapy. Topics: Adolescent; Antineoplastic Agents; Brain; Brain Stem Neoplasms; Chemotherapy, Adjuvant; Child; Child, Preschool; Contrast Media; Disease Progression; Disease-Free Survival; Erlotinib Hydrochloride; Female; Glioma; Humans; Magnetic Resonance Imaging; Male; Prospective Studies; Sirolimus; Statistics, Nonparametric; Survival Analysis; Time Factors; Tumor Burden | 2017 |
Cobalt chloride treatment induces autophagic apoptosis in human glioma cells via a p53-dependent pathway.
Malignant glioma is the most aggressive brain tumor. Hypoxic condition has been explored for killing cancer stem cells or drug-resistant tumor cells. This study investigated the effects of hypoxia on autophagic death and the possible mechanisms. Exposure of human malignant glioma U87-MG cells to cobalt chloride (CoCl2) increased cellular hypoxia-inducible factor-1α levels and concurrently decreased cell viability concentration- and time-dependently. In parallel, treatment with CoCl2 suppressed proliferation of human U87-MG cells. Autophagic cells and levels of LC3-II were concentration- and time-dependently induced in human U87-MG cells after exposure to CoCl2. However, pretreatment with 3-mehyladenine (3-MA) and chloroquine, inhibitors of cell autophagy, caused significant alleviations in CoCl2-induced cell autophagy. In contrast, exposure to rapamycin, an inducer of cell autophagy, synergistically induced hypoxia-induced autophagy of U87-MG cells. Administration of human U87-MG cells with CoCl2 triggered caspase-3 activation and cell apoptosis. Interestingly, pretreatment with 3-MA and chloroquine remarkably suppressed CoCl2-induced caspase-3 activation and cell apoptosis. Application of p53 small interference (si)RNA into human U87-MG cells downregulated levels of this protein and simultaneously lowered hypoxia- and 3-MA-induced alterations in cell autophagy, apoptosis, and death. The hypoxia-induced autophagy and apoptosis of DBTRG-05MG cells were significantly lowered by 3-MA pretreatment and p53 knockdown. Therefore, the present study shows that CoCl2 treatment can induce autophagy of human glioma cells and subsequent autophagic apoptosis via a p53-dependent pathway. Hypoxia-induced autophagic apoptosis may be applied as a therapeutic strategy for treatment of glioma patients. Topics: Adenine; Antimutagenic Agents; Apoptosis; Autophagy; Brain Neoplasms; Caspase 3; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chloroquine; Cobalt; Glioma; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Microtubule-Associated Proteins; Reactive Oxygen Species; RNA Interference; RNA, Small Interfering; Sirolimus; Tumor Suppressor Protein p53 | 2017 |
mTOR inhibition decreases SOX2-SOX9 mediated glioma stem cell activity and temozolomide resistance.
SOX2 and SOX9 are commonly overexpressed in glioblastoma, and regulate the activity of glioma stem cells (GSCs). Their specific and overlapping roles in GSCs and glioma treatment remain unclear.. SOX2 and SOX9 levels were examined in human biopsies. Gain and loss of function determined the impact of altering SOX2 and SOX9 on cell proliferation, senescence, stem cell activity, tumorigenesis and chemoresistance.. SOX2 and SOX9 expression correlates positively in glioma cells and glioblastoma biopsies. High levels of SOX2 bypass cellular senescence and promote resistance to temozolomide. Mechanistic investigations revealed that SOX2 acts upstream of SOX9. mTOR genetic and pharmacologic (rapamycin) inhibition decreased SOX2 and SOX9 expression, and reversed chemoresistance.. Our findings reveal SOX2-SOX9 as an oncogenic axis that regulates stem cell properties and chemoresistance. We identify that rapamycin abrogate SOX protein expression and provide evidence that a combination of rapamycin and temozolomide inhibits tumor growth in cells with high SOX2/SOX9. Topics: Adult; Animals; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Cell Line, Tumor; Dacarbazine; Drug Resistance, Neoplasm; Gene Expression Regulation, Neoplastic; Glioblastoma; Glioma; Humans; Mice; Mice, Inbred NOD; Mice, Nude; Mice, SCID; Sirolimus; SOX9 Transcription Factor; SOXB1 Transcription Factors; Temozolomide; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays | 2016 |
Honokiol induces autophagic cell death in malignant glioma through reactive oxygen species-mediated regulation of the p53/PI3K/Akt/mTOR signaling pathway.
Honokiol, an active constituent extracted from the bark of Magnolia officinalis, possesses anticancer effects. Apoptosis is classified as type I programmed cell death, while autophagy is type II programmed cell death. We previously proved that honokiol induces cell cycle arrest and apoptosis of U87 MG glioma cells. Subsequently in this study, we evaluated the effect of honokiol on autophagy of glioma cells and examined the molecular mechanisms. Administration of honokiol to mice with an intracranial glioma increased expressions of cleaved caspase 3 and light chain 3 (LC3)-II. Exposure of U87 MG cells to honokiol also induced autophagy in concentration- and time-dependent manners. Results from the addition of 3-methyladenine, an autophagy inhibitor, and rapamycin, an autophagy inducer confirmed that honokiol-induced autophagy contributed to cell death. Honokiol decreased protein levels of PI3K, phosphorylated (p)-Akt, and p-mammalian target of rapamycin (mTOR) in vitro and in vivo. Pretreatment with a p53 inhibitor or transfection with p53 small interfering (si)RNA suppressed honokiol-induced autophagy by reversing downregulation of p-Akt and p-mTOR expressions. In addition, honokiol caused generation of reactive oxygen species (ROS), which was suppressed by the antioxidant, vitamin C. Vitamin C also inhibited honokiol-induced autophagic and apoptotic cell death. Concurrently, honokiol-induced alterations in levels of p-p53, p53, p-Akt, and p-mTOR were attenuated following vitamin C administration. Taken together, our data indicated that honokiol induced ROS-mediated autophagic cell death through regulating the p53/PI3K/Akt/mTOR signaling pathway. Topics: Adenine; Animals; Apoptosis; Ascorbic Acid; Autophagy; Biphenyl Compounds; Caspase 3; Cell Line, Tumor; Dose-Response Relationship, Drug; Down-Regulation; Glioma; Lignans; Mice; Microtubule-Associated Proteins; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; RNA, Small Interfering; Signal Transduction; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Tumor Suppressor Protein p53 | 2016 |
Post-transcriptional regulation of 5'-untranslated regions of human Transient Receptor Potential Vanilloid type-1 (TRPV-1) channels: role in the survival of glioma patients.
The Transient Receptor Potential Vanilloid type-1 (TRPV1) channel is a non-selective cation channel belonging to the Transient Receptor Potential family; variation of its expression has been correlated to glioma progression. In human, TRPV1 transcripts display a remarkable homogeneity differing only for the 5'-untranslated region (5'UTR) sequence that generates four variants encoding the same protein. Herein, we investigated the role of the 5'UTR sequences in TRPV1 transcripts stability, regulation of translation, expression in glioma cells and tissues. In addition, the expression of 5'UTR TRPV1 variants as prognostic factor in the survival of glioblastoma patients was evaluated. The expression level for each 5'UTR and their stability was evaluated by RT-PCR analysis. The effect of rapamycin and interferon-gamma in 5'UTR-regulating TRPV1 translation was determined by western blot analysis in glioma cell lines. We demonstrated that the 5'UTR influences the stability and translation efficacy of TRPV1 transcripts, and that TRPV1 variant three (TRPV1v3) was the most stable and the only variant expressed in GBM samples and in glioma stem-like cells. Furthermore, we found that TRPV1v3 expression levels correlate with patient's survival, suggesting that it may represent a potential prognostic marker for patients with glioma. Topics: 5' Untranslated Regions; Brain Neoplasms; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Glioma; Half-Life; Humans; Interferon-gamma; Kaplan-Meier Estimate; Neoplastic Stem Cells; Nucleic Acid Conformation; Proportional Hazards Models; RNA Processing, Post-Transcriptional; RNA Stability; RNA, Messenger; Sirolimus; Time Factors; Transfection; TRPV Cation Channels | 2016 |
Inhibition of the NOTCH pathway using γ-secretase inhibitor RO4929097 has limited antitumor activity in established glial tumors.
Notch signaling is altered in many cancers. Our previous findings in primary pediatric ependymoma support a role for NOTCH in glial oncogenesis. The present study evaluates the γ-secretase inhibitor RO4929097 in glial tumor models. The expression of Notch pathway genes was evaluated using real-time RT-PCR in 21 ependymoma and glioma models. NOTCH1 mutations were analyzed by DNA sequencing. RO4929097 activity was evaluated in vitro and in vivo, as a single agent and in combination, in glioma and ependymoma models. Notch pathway genes are overexpressed in ependymomas and gliomas along with FBXW7 downregulation. NOTCH1 mutations in the TAD domain were observed in 20% (2/10) of ependymoma primary cultures. Blocking the Notch pathway with the γ-secretase inhibitor RO4929097 reduced cell density and viability in ependymoma short-term cultures. When combined with chemotherapeutic agents, RO4929097 enhanced temozolomide effects in ependymoma short-term cultures and potentiated the cytotoxicity of etoposide, cisplatinum, and temozolomide in glioma cells. RO4929097, in combined treatment with mTOR inhibition, potentiated cytotoxicity in vitro, but did not enhance antitumor effects in vivo. In contrast, RO4929097 enhanced irradiation effects in glioma and ependymoma xenografts and showed tumor growth inhibition in advanced-stage IGRG121 glioblastoma xenografts. RO4929097-mediated effects were independent of NOTCH1 mutation status or expression levels, but associated with low IL-6 levels. In established glial tumor models, NOTCH inhibition had limited effects as a single agent, but enhanced efficacy when combined with DNA-interfering agents. These preclinical data need to be considered for further clinical development of NOTCH inhibitors in glial tumors. Topics: Amyloid Precursor Protein Secretases; Animals; Antineoplastic Combined Chemotherapy Protocols; Benzazepines; Cell Line, Tumor; Cell Survival; Ependymoma; Gene Expression Regulation, Neoplastic; Glioma; Humans; Interleukin-6; Mice, Nude; Molecular Targeted Therapy; Protein Kinase Inhibitors; Receptor, Notch1; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays | 2015 |
Single-cell analysis challenges the connection between autophagy and senescence induced by DNA damage.
Autophagy and senescence have been described as central features of cell biology, but the interplay between these mechanisms remains obscure. Using a therapeutically relevant model of DNA damage-induced senescence in human glioma cells, we demonstrated that acute treatment with temozolomide induces DNA damage, a transitory activation of PRKAA/AMPK-ULK1 and MAPK14/p38 and the sustained inhibition of AKT-MTOR. This produced a transient induction of autophagy, which was followed by senescence. However, at the single cell level, this coordinated transition was not observed, and autophagy and senescence were triggered in a very heterogeneous manner. Indeed, at a population level, autophagy was highly negatively correlated with senescence markers, while in single cells this correlation did not exist. The inhibition of autophagy triggered apoptosis and decreased senescence, while its activation increased temozolomide-induced senescence, showing that DNA damage-induced autophagy acts by suppressing apoptosis. Topics: AMP-Activated Protein Kinases; Apoptosis; Autophagy; Autophagy-Related Protein-1 Homolog; Cell Cycle Checkpoints; Cell Line, Tumor; Cellular Senescence; Dacarbazine; DNA Damage; Enzyme Activation; Glioma; Green Fluorescent Proteins; Humans; Intracellular Signaling Peptides and Proteins; Models, Biological; p38 Mitogen-Activated Protein Kinases; Phenotype; Protein Serine-Threonine Kinases; Single-Cell Analysis; Sirolimus; Temozolomide; Time Factors; TOR Serine-Threonine Kinases | 2015 |
Loss of Tsc1 accelerates malignant gliomagenesis when combined with oncogenic signals.
Glioblastomas frequently harbour genetic lesions that stimulate the activity of mammalian target of rapamycin complex 1 (mTORC1). Loss of heterozygosity of tuberous sclerosis complex 1 (TSC1) or TSC2, which together form a critical negative regulator of mTORC1, is also seen in glioblastoma; however, it is not known how loss of the TSC complex affects the development of malignant gliomas. Here we investigated the role of Tsc1 in gliomagenesis in mice. Tsc1 deficiency up-regulated mTORC1 activity and suppressed the proliferation of neural stem/progenitor cells (NSPCs) in a serial neurosphere-forming assay, suggesting that Tsc1-deficient NSPCs have defective self-renewal activity. The neurosphere-forming capacity of Tsc1-deficient NSPCs was restored by p16(Ink4a)p19(Arf) deficiency. Combined Tsc1 and p16(Ink4a)p19(Arf) deficiency in NSPCs did not cause gliomagenesis in vivo. However, in a glioma model driven by an active mutant of epidermal growth factor receptor (EGFR), EGFRvIII, loss of Tsc1 resulted in an earlier onset of glioma development. The mTORC1 hyperactivation by Tsc1 deletion accelerated malignant phenotypes, including increased tumour mass and enhanced microvascular formation, leading to intracranial haemorrhage. These data demonstrate that, although mTORC1 hyperactivation itself may not be sufficient for gliomagenesis, it is a potent modifier of glioma development when combined with oncogenic signals. Topics: Animals; Carcinogenesis; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p19; ErbB Receptors; Glioma; Hemorrhage; Humans; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Neural Stem Cells; Phenotype; Signal Transduction; Sirolimus; Spheroids, Cellular; TOR Serine-Threonine Kinases; Tuberous Sclerosis Complex 1 Protein; Tumor Suppressor Proteins | 2014 |
MNK1 pathway activity maintains protein synthesis in rapalog-treated gliomas.
High levels of mammalian target of rapamycin complex 1 (mTORC1) activity in malignant gliomas promote tumor progression, suggesting that targeting mTORC1 has potential as a therapeutic strategy. Remarkably, clinical trials in patients with glioma revealed that rapamycin analogs (rapalogs) have limited efficacy, indicating activation of resistance mechanisms. Targeted depletion of MAPK-interacting Ser/Thr kinase 1 (MNK1) sensitizes glioma cells to the mTORC1 inhibitor rapamycin through an indistinct mechanism. Here, we analyzed how MNK1 and mTORC1 signaling pathways regulate the assembly of translation initiation complexes, using the cap analog m7GTP to enrich for initiation complexes in glioma cells followed by mass spectrometry-based quantitative proteomics. Association of eukaryotic translation initiation factor 4E (eIF4E) with eIF4E-binding protein 1 (4EBP1) was regulated by the mTORC1 pathway, whereas pharmacological blocking of MNK activity by CGP57380 or MNK1 knockdown, along with mTORC1 inhibition by RAD001, increased 4EBP1 binding to eIF4E. Furthermore, combined MNK1 and mTORC1 inhibition profoundly inhibited 4EBP1 phosphorylation at Ser65, protein synthesis and proliferation in glioma cells, and reduced tumor growth in an orthotopic glioblastoma (GBM) mouse model. Immunohistochemical analysis of GBM samples revealed increased 4EBP1 phosphorylation. Taken together, our data indicate that rapalog-activated MNK1 signaling promotes glioma growth through regulation of 4EBP1 and indicate a molecular cross-talk between the mTORC1 and MNK1 pathways that has potential to be exploited therapeutically. Topics: Aniline Compounds; Animals; Brain Neoplasms; Cell Line, Tumor; Eukaryotic Initiation Factor-4E; Female; Gene Expression Regulation, Neoplastic; Glioma; Humans; Immunohistochemistry; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Knockout; Mice, Nude; Multiprotein Complexes; Neoplasm Transplantation; Phosphorylation; Protein Binding; Protein Biosynthesis; Protein Serine-Threonine Kinases; Purines; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases | 2014 |
Mammalian target of rapamycin signaling is involved in the vasculogenic mimicry of glioma via hypoxia-inducible factor-1α.
The mammalian target of rapamycin (mTOR) is a crucial regulator in malignant gliomas. Vasculogenic mimicry (VM) describes functional channels established by highly malignant tumor cells that is different from endothelium-lined blood vessels. Our previous studies confirmed the existence and clinical significance of VM in medulloblastoma and glioblastoma. In the present study, by immunohistochemical and CD34/PAS histochemical double-staining, 34 cases (26.8%) with VM structures were identified among a total of 127 glioma cases, and these VM structures were associated with mTOR expression in the glioma specimens. In vitro, U87 malignant glioblastoma cells formed tube structures similar to HUVECs on Matrigel in 3D culture, and mTOR-specific inhibitor rapamycin inhibited VM formation in the U87 malignant glioblastoma cells under both normoxia and hypoxia. In addition, rapamycin and mTOR siRNA inhibited molecules in the signaling cascade of VM formation, particularly HIF-1α. Taken together, our results demonstrated that mTOR signaling is involved in VM formation, and may be a potential therapeutic target for gliomas. Topics: Adult; Aged; Aged, 80 and over; Cell Hypoxia; Cell Line, Tumor; Female; Glioma; Human Umbilical Vein Endothelial Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; In Vitro Techniques; Male; Middle Aged; Neovascularization, Pathologic; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases | 2014 |
Transformation of quiescent adult oligodendrocyte precursor cells into malignant glioma through a multistep reactivation process.
How malignant gliomas arise in a mature brain remains a mystery, hindering the development of preventive and therapeutic interventions. We previously showed that oligodendrocyte precursor cells (OPCs) can be transformed into glioma when mutations are introduced perinatally. However, adult OPCs rarely proliferate compared with their perinatal counterparts. Whether these relatively quiescent cells have the potential to transform is unknown, which is a critical question considering the late onset of human glioma. Additionally, the premalignant events taking place between initial mutation and a fully developed tumor mass are particularly poorly understood in glioma. Here we used a temporally controllable Cre transgene to delete p53 and NF1 specifically in adult OPCs and demonstrated that these cells consistently give rise to malignant gliomas. To investigate the transforming process of quiescent adult OPCs, we then tracked these cells throughout the premalignant phase, which revealed a dynamic multistep transformation, starting with rapid but transient hyperproliferative reactivation, followed by a long period of dormancy, and then final malignant transformation. Using pharmacological approaches, we discovered that mammalian target of rapamycin signaling is critical for both the initial OPC reactivation step and late-stage tumor cell proliferation and thus might be a potential target for both glioma prevention and treatment. In summary, our results firmly establish the transforming potential of adult OPCs and reveal an actionable multiphasic reactivation process that turns slowly dividing OPCs into malignant gliomas. Topics: Animals; Antineoplastic Agents; Blotting, Western; Brain Neoplasms; Cell Cycle; Cell Differentiation; Cell Proliferation; Cell Transformation, Neoplastic; Gene Expression Profiling; Glioma; Immunohistochemistry; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Mice, Transgenic; Neural Stem Cells; Neurofibromin 1; Oligodendroglia; Oligonucleotide Array Sequence Analysis; Sirolimus; Tamoxifen; Tumor Cells, Cultured; Tumor Suppressor Protein p53 | 2014 |
Blockade of mTOR signaling via rapamycin combined with immunotherapy augments antiglioma cytotoxic and memory T-cell functions.
The success of immunotherapeutic approaches targeting glioblastoma multiforme (GBM) demands a robust antiglioma T-cell cytotoxic and memory response. Recent evidence suggests that rapamycin regulates T-cell differentiation. Herein, we tested whether administration of rapamycin could enhance the efficacy of immunotherapy utilizing Fms-like tyrosine kinase 3 ligand (Ad-Flt3L) and thymidine kinase/ganciclovir (Ad-TK/GCV). Using the refractory rat RG2 glioma model, we demonstrate that administration of rapamycin with Ad-Flt3L + Ad-TK/GCV immunotherapy enhanced the cytotoxic activity of antitumor CD8(+) T cells. Rats treated with rapamycin + Ad-Flt3L + Ad-TK/GCV exhibited massive reduction in the tumor volume and extended survival. Rapamycin administration also prolonged the survival of Ad-Flt3L + Ad-TK/GCV-treated GL26 tumor-bearing mice, associated with an increase in the frequency of tumor-specific and IFNγ(+) CD8(+) T cells. More importantly, rapamycin administration, even for a short interval, elicited a potent long-lasting central memory CD8(+) T-cell response. The enhanced memory response translated to an increased frequency of tumor-specific CD8(+) T cells within the tumor and IFNγ release, providing the mice with long-term survival advantage in response to tumor rechallenge. Our data, therefore, point to rapamycin as an attractive adjuvant to be used in combination with immunotherapy in a phase I clinical trial for GBM. Topics: Adenoviridae; Animals; Antigens; Antigens, Surface; Cell Line, Tumor; Cytokines; Dendritic Cells; Disease Models, Animal; Ganciclovir; Genetic Therapy; Genetic Vectors; Glioblastoma; Glioma; Immunologic Memory; Immunophenotyping; Immunotherapy; Membrane Proteins; Mice; Rats; Signal Transduction; Sirolimus; T-Lymphocyte Subsets; T-Lymphocytes, Cytotoxic; Thymidine Kinase; TOR Serine-Threonine Kinases | 2014 |
Cellular factors promoting resistance to effective treatment of glioma with oncolytic myxoma virus.
Oncolytic virus therapy is being evaluated in clinical trials for human glioma. While it is widely assumed that the immune response of the patient to the virus infection limits the utility of the therapy, investigations into the specific cell type(s) involved in this response have been performed using nonspecific pharmacologic inhibitors or allogeneic models with compromised immunity. To identify the immune cells that participate in clearing an oncolytic infection in glioma, we used flow cytometry and immunohistochemistry to immunophenotype an orthotopic glioma model in immunocompetent mice after Myxoma virus (MYXV) administration. These studies revealed a large resident microglia and macrophage population in untreated tumors, and robust monocyte, T-, and NK cell infiltration 3 days after MYXV infection. To determine the role on the clinical utility of MYXV therapy for glioma, we used a combination of knockout mouse strains and specific immunocyte ablation techniques. Collectively, our experiments identify an important role for tumor-resident myeloid cells and overlapping roles for recruited NK and T cells in the clearance and efficacy of oncolytic MYXV from gliomas. Using a cyclophosphamide regimen to achieve lymphoablation prior and during MYXV treatment, we prevented treatment-induced peripheral immunocyte recruitment and, surprisingly, largely ablated the tumor-resident macrophage population. Virotherapy of cyclophosphamide-treated animals resulted in sustained viral infection within the glioma as well as a substantial survival advantage. This study demonstrates that resistance to MYXV virotherapy in syngeneic glioma models involves a multifaceted cellular immune response that can be overcome with cyclophosphamide-mediated lymphoablation. Topics: Animals; Brain Neoplasms; Cell Line, Tumor; Cyclophosphamide; Flow Cytometry; Glioma; Humans; Immunity, Cellular; Killer Cells, Natural; Mice; Myxoma virus; Oncolytic Virotherapy; Oncolytic Viruses; Sirolimus; Xenograft Model Antitumor Assays | 2014 |
Systemic rapamycin alone may not be a treatment option for malignant glioma: evidence from an in vivo study.
The mammalian target of rapamycin (mTOR) plays a central role in regulating the proliferation of cancer cells, and mTOR-specific inhibitors such as rapamycin analogs are considered as a promising therapy for malignant glioma. In this study, we investigated the possibility of using mTOR inhibitors to treat gliomas. We used a molecular marker, phosphorylation of S6 protein, to monitor biological effects of mTOR inhibitors within xenografts. Phosphorylation was decreased more in U87MG glioma after treatment with high doses of rapamycin or its analog, torisel (10 mg/kg or 25 mg/kg), but only slightly after a low dose of rapamycin (3 mg/kg). This effect correlated with enhanced survival of rats after weekly peritoneal injections of both drugs at the highest two doses but not at the low dose. High doses of both drugs caused weight loss in rats. Clinical trial data indicates that low doses of Torisel (<3 mg/kg) were not efficacious in recurrent GBM. It is concluded that systemic administration of rapamycin analogues may not be a treatment option for patients with malignant glioma due to the intolerability of high doses that might otherwise be effective. The present study underscores the need for better pre-clinical evaluation of drugs with respect to therapeutic window. Topics: Animals; Brain Neoplasms; Cell Line, Tumor; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Glioma; Humans; Immunosuppressive Agents; Male; Neoplasm Transplantation; Phosphorylation; Protein Kinases; Rats; Rats, Nude; Sirolimus; Time Factors; Xenograft Model Antitumor Assays | 2012 |
Local delivery of rapamycin: a toxicity and efficacy study in an experimental malignant glioma model in rats.
Rapamycin, an anti-proliferative agent, is effective in the treatment of renal cell carcinoma and recurrent breast cancers. We proposed that this potent mammalian target of rapamycin inhibitor may be useful for the treatment of gliomas as well. We examined the cytotoxicity of rapamycin against a rodent glioma cell line, determined the toxicity of rapamycin when delivered intracranially, and investigated the efficacy of local delivery of rapamycin for the treatment of experimental malignant glioma in vivo. We also examined the dose-dependent efficacy of rapamycin and the effect when locally delivered rapamycin was combined with radiation therapy. Rapamycin was cytotoxic to 9L cells, causing 34% growth inhibition at a concentration of 0.01 µg/mL. No in vivo toxicity was observed when rapamycin was incorporated into biodegradable caprolactone-glycolide (35:65) polymer beads at 0.3%, 3%, and 30% loading doses and implanted intracranially. Three separate efficacy studies were performed to test the reproducibility of the effect of the rapamycin beads as well as the validity of this treatment approach. Animals treated with the highest dose of rapamycin beads tested (30%) consistently demonstrated significantly longer survival durations than the control and placebo groups. All dose-escalating rapamycin bead treatment groups (0.3%, 3% and 30%), treated both concurrently with tumor and in a delayed manner after tumor placement, experienced a significant increase in survival, compared with controls. Radiation therapy in addition to the simultaneous treatment with 30% rapamycin beads led to significantly longer survival duration than either therapy alone. These results suggest that the local delivery of rapamycin for the treatment of gliomas should be further investigated. Topics: Animals; Antibiotics, Antineoplastic; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Combined Modality Therapy; Glioma; Humans; Neoplasms, Experimental; Polymers; Radiotherapy; Rats; Rats, Inbred F344; Sirolimus; Survival Rate | 2011 |
Rapamycin induces differentiation of glioma stem/progenitor cells by activating autophagy.
Glioma stem/progenitor cells (GSPCs) are considered to be responsible for the initiation, propagation, and recurrence of gliomas. The factors determining their differentiation remain poorly defined. Accumulating evidences indicate that alterations in autophagy may influence cell fate during mammalian development and differentiation. Here, we investigated the role of autophagy in GSPC differentiation. SU-2 cells were treated with rapamycin, 3-methyladenine (3-MA) plus rapamycin, E64d plus rapamycin, or untreated as control. SU-2 cell xenografts in nude mice were treated with rapamycin or 3-MA plus rapamycin, or untreated as control. Western blotting and immunocytochemistry showed up-regulation of microtubule-associated protein light chain-3 (LC3)-II in rapamycin-treated cells. The neurosphere formation rate and the number of cells in each neurosphere were significantly lower in the rapamycin treatment group than in other groups. Real-time PCR and immunocytochemistry showed down-regulation of stem/progenitor cell markers and up-regulation of differentiation markers in rapamycin-treated cells. Transmission electron microscopy revealed autophagy activation in rapamycin-treated tumor cells in mice. Immunohistochemistry revealed decreased Nestin-positive cells and increased GFAP-positive cells in rapamycin-treated tumor sections. These results indicate that rapamycin induces differentiation of GSPCs by activating autophagy. Topics: Adenine; Animals; Antibiotics, Antineoplastic; Autophagy; Brain Neoplasms; Cell Differentiation; Cell Line, Tumor; Female; Glial Fibrillary Acidic Protein; Glioma; Humans; Leucine; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Microtubule-Associated Proteins; Neoplastic Stem Cells; RNA, Messenger; Sirolimus; Xenograft Model Antitumor Assays | 2011 |
Autophagy impairment inhibits differentiation of glioma stem/progenitor cells.
Despite of similarities between glioma stem/progenitor cells (GSPCs) and neural stem/progenitor cells (NSPCs), inhibition of differentiation is a distinct characteristic of GSPCs. In this study, we investigated the effects of autophagy impairment on inhibition of differentiation of GSPC, and its molecular mechanism. GSPCs were kept by our laboratory; NSPCs were isolated from human fetal brain tissue. We found that the autophagic activity in GSPCs was significantly lower than that in NSPCs. However, the autophagic activity markedly increased after GSPCs were induced to differentiate by fetal calf serum (FCS). The autophagy inhibitors 3-methyladenine and Bafilomycin A1 (BFA) inhibited the FSC-induced differentiation of GSPCs. And autophagy activator Rapamycin could promote differentiation of GSPCs. In order to disclose whether the loss of PTEN in GSPC is related to the deficiency of autophagic activity in GSPCs (for PTEN being lost in the GSPCs studied by us), we introduced the wild type gene of PTEN into GSPCs, and found that the autophagic activity was restored significantly after the gene transduction. The low autophagic activity in GSPCs leads to the inhibition of differentiation of GSPCs, and the loss of PTEN in GSPCs probably is an underlying mechanism for the low autophagic activity in GSPCs. These results suggest that bust autophagic activity target at PTEN might be a potential therapy target for glioma therapy. Topics: Adenine; Autophagy; Blotting, Western; Cadaverine; Cell Differentiation; Cells, Cultured; Central Nervous System Agents; Glioma; Humans; Immunohistochemistry; Macrolides; Microscopy, Electron, Transmission; Neurons; PTEN Phosphohydrolase; Reverse Transcriptase Polymerase Chain Reaction; Sirolimus; Stem Cells; Transduction, Genetic | 2010 |
Myxoma virus virotherapy for glioma in immunocompetent animal models: optimizing administration routes and synergy with rapamycin.
Oncolytic myxoma virus (MYXV) is being developed as a novel virotherapeutic against human brain cancer and has promising activity against human brain tumor models in immunocompromised hosts. Because an intact immune system could reduce its efficacy, the purpose of this study was to evaluate the oncolytic potential of MYXV in immunocompetent racine glioma models. Here, we report that MYXV infects and kills all racine cell glioma lines and that its effects are enhanced by rapamycin. Intratumoral administration of MYXV with rapamycin improved viral replication in the tumor and significantly prolonged host survival. Similarly, coadministration via a method of convection-enhanced delivery (CED) enhanced viral replication and efficacy in vivo. Mechanisms by which rapamycin improved MYXV oncolysis included an inhibition of type I IFN production in vitro and a reduction of intratumoral infiltration of CD68(+) microglia/macrophages and CD163(+) macrophages in vivo. Our findings define a method to improve MYXV efficacy against gliomas by rapamycin coadministration, which acts to promote immune responses engaged by viral delivery. Topics: Animals; Antibiotics, Antineoplastic; Brain Neoplasms; Cell Line, Tumor; Drug Synergism; Glioma; Immunocompetence; Mice; Myxoma virus; NIH 3T3 Cells; Oncolytic Virotherapy; Rats; Rats, Inbred F344; Sirolimus; Virus Replication | 2010 |
Vesicular stomatitis virus oncolysis is potentiated by impairing mTORC1-dependent type I IFN production.
Oncolytic viruses constitute a promising therapy against malignant gliomas (MGs). However, virus-induced type I IFN greatly limits its clinical application. The kinase mammalian target of rapamycin (mTOR) stimulates type I IFN production via phosphorylation of its effector proteins, 4E-BPs and S6Ks. Here we show that mouse embryonic fibroblasts and mice lacking S6K1 and S6K2 are more susceptible to vesicular stomatitis virus (VSV) infection than their WT counterparts as a result of an impaired type I IFN response. We used this knowledge to employ a pharmacoviral approach to treat MGs. The highly specific inhibitor of mTOR rapamycin, in combination with an IFN-sensitive VSV-mutant strain (VSV(DeltaM51)), dramatically increased the survival of immunocompetent rats bearing MGs. More importantly, VSV(DeltaM51) selectively killed tumor, but not normal cells, in MG-bearing rats treated with rapamycin. These results demonstrate that reducing type I IFNs through inhibition of mTORC1 is an effective strategy to augment the therapeutic activity of VSV(DeltaM51). Topics: Animals; Cell Line; Cell Line, Tumor; Female; Glioma; Interferon Type I; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Knockout; Multiprotein Complexes; Neoplasm Transplantation; Oncolytic Virotherapy; Proteins; Rats; Rats, Inbred F344; Ribosomal Protein S6 Kinases; Ribosomal Protein S6 Kinases, 90-kDa; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Vesicular Stomatitis; Vesiculovirus | 2010 |
Efficacy and safety/toxicity study of recombinant vaccinia virus JX-594 in two immunocompetent animal models of glioma.
The purpose of this study was to investigate the oncolytic potential of the recombinant, granulocyte macrophage colony-stimulating factor (GM-CSF)-expressing vaccinia virus (VV) JX-594 in experimental malignant glioma (MGs) in vitro and in immunocompetent rodent models. We have found that JX-594 killed all MG cell lines tested in vitro. Intratumoral (i.t.) administration of JX-594 significantly inhibited tumor growth and prolonged survival in rats-bearing RG2 intracranial (i.c.) tumors and mice-bearing GL261 brain tumors. Combination therapy with JX-594 and rapamycin significantly increased viral replication and further prolonged survival in both immunocompetent i.c. MG models with several animals considered "cured" (three out of seven rats >120 days, terminated experiment). JX-594 infected and killed brain tumor-initiating cells (BTICs) from patient samples grown ex vivo, and did so more efficiently than other oncolytic viruses MYXV, Reovirus type-3, and VSV(ΔM51). Additional safety/toxicity studies in nontumor-bearing rodents treated with a supratherapeutic dose of JX-594 demonstrated GM-CSF-dependent inflammation and necrosis. These results suggest that i.c. administered JX-594 triggers a predictable GM-CSF-mediated inflammation in murine models. Before proceeding to clinical trials, JX-594 should be evaluated in the brains of nonhuman primates and optimized for the viral doses, delivery routes as well as the combination agents (e.g., mTOR inhibitors). Topics: Animals; Antibiotics, Antineoplastic; Brain Neoplasms; Combined Modality Therapy; Disease Models, Animal; Female; Genetic Vectors; Glioma; Granulocyte-Macrophage Colony-Stimulating Factor; Immunoenzyme Techniques; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oncolytic Virotherapy; Rats; Rats, Inbred F344; Sirolimus; Survival Rate; Transgenes; Tumor Cells, Cultured; Vaccines, Synthetic; Vaccinia virus; Virus Replication | 2010 |
Akt and autophagy cooperate to promote survival of drug-resistant glioma.
Although the phosphatidylinositol 3-kinase to Akt to mammalian target of rapamycin (PI3K-Akt-mTOR) pathway promotes survival signaling, inhibitors of PI3K and mTOR induce minimal cell death in PTEN (phosphatase and tensin homolog deleted from chromosome 10) mutant glioma. Here, we show that the dual PI3K-mTOR inhibitor PI-103 induces autophagy in a form of glioma that is resistant to therapy. Inhibitors of autophagosome maturation cooperated with PI-103 to induce apoptosis through the mitochondrial pathway, indicating that the cellular self-digestion process of autophagy acted as a survival signal in this setting. Not all inhibitors of mTOR synergized with inhibitors of autophagy. Rapamycin delivered alone induced autophagy, yet cells survived inhibition of autophagosome maturation because of rapamycin-mediated activation of Akt. In contrast, adenosine 5'-triphosphate-competitive inhibitors of mTOR stimulated autophagy more potently than did rapamycin, with inhibition of mTOR complexes 1 and 2 contributing independently to induction of autophagy. We show that combined inhibition of PI3K and mTOR, which activates autophagy without activating Akt, cooperated with inhibition of autophagy to cause glioma cells to undergo apoptosis. Moreover, the PI3K-mTOR inhibitor NVP-BEZ235, which is in clinical use, synergized with the lysosomotropic inhibitor of autophagy, chloroquine, another agent in clinical use, to induce apoptosis in glioma xenografts in vivo, providing a therapeutic approach potentially translatable to humans. Topics: Animals; Autophagy; Cell Line, Tumor; Chloroquine; Drug Synergism; Flow Cytometry; Furans; Glioma; Histological Techniques; Humans; Imidazoles; Immunoblotting; Immunohistochemistry; Mice; Mice, Inbred BALB C; Microscopy, Confocal; Mitochondria; Mutation; Oncogene Protein v-akt; Phosphoinositide-3 Kinase Inhibitors; PTEN Phosphohydrolase; Pyridines; Pyrimidines; Quinolines; Sirolimus; TOR Serine-Threonine Kinases; Transplantation, Heterologous | 2010 |
Efficacy of systemically administered oncolytic vaccinia virotherapy for malignant gliomas is enhanced by combination therapy with rapamycin or cyclophosphamide.
The oncolytic effects of a systemically delivered, replicating, double-deleted vaccinia virus has been previously shown for the treatment of many cancers, including colon, ovarian, and others. The purpose of this study was to investigate the oncolytic potential of double-deleted vaccinia virus alone or in combination with rapamycin or cyclophosphamide to treat malignant gliomas in vitro and in vivo.. Rat (RG2, F98, C6) and human (A172, U87MG, U118) glioma cell lines were cultured in vitro and treated with live or UV-inactivated vaccinia virus. Viral gene [enhanced green fluorescent protein (EGFP)] expression by fluorescence-activated cell sorting, relative cell viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and assays for cytopathic effects were examined. S.c. murine tumor xenografts (U87MG, U118, C6) and i.c. (RG2, F98) tumor models in immunocompetent rats were treated with systemic administration of EGFP-expressing vaccinia virus (vvDD-EGFP), alone or in combination with rapamycin or cyclophosphamide, or controls. Tumor size, viral biodistribution, and animal survival were assessed. Lastly, the oncolytic effects of vvDD-EGFP on human malignant glioma explants were evaluated.. vvDD-EGFP was able to infect and kill glioma cells in vitro. A single systemic dose of vvDD-EGFP significantly inhibited the growth of xenografts in athymic mice. Systemic delivery of vvDD-EGFP alone was able to target solitary and multifocal i.c. tumors and prolong survival of immunocompetent rats, whereas combination therapy with rapamycin or cyclophosphamide enhanced viral replication and further prolonged survival. Finally, vvDD-EGFP was able to infect and kill ex vivo primary human malignant gliomas.. These results suggest that vvDD-EGFP is a promising novel agent for human malignant glioma therapy, and in combination with immunosuppressive agents, may lead to prolonged survival from this disease. Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Combined Modality Therapy; Cyclophosphamide; Female; Glioma; Humans; Immunosuppressive Agents; Mice; Mice, Nude; Oncolytic Virotherapy; Rats; Sirolimus; Vaccinia virus; Virus Replication | 2009 |
Antagonism of the mammalian target of rapamycin selectively mediates metabolic effects of epidermal growth factor receptor inhibition and protects human malignant glioma cells from hypoxia-induced cell death.
Although inhibition of the epidermal growth factor receptor is a plausible therapy for malignant gliomas that, in vitro, enhances apoptosis, the results of clinical trials have been disappointing. The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that integrates starvation signals and generates adaptive responses that aim at the maintenance of energy homeostasis. Antagonism of mTOR has been suggested as a strategy to augment the efficacy of epidermal growth factor receptor inhibition by interfering with deregulated signalling cascades downstream of Akt. Here we compared effects of antagonism of mTOR utilizing rapamycin or a small hairpin RNA-mediated gene silencing to those of epidermal growth factor receptor inhibition or combined inhibition of epidermal growth factor receptor and mTOR in human malignant glioma cells. In contrast to epidermal growth factor receptor inhibition, mTOR antagonism neither induced cell death nor enhanced apoptosis induced by CD95 ligand or chemotherapeutic drugs. However, mTOR inhibition mimicked the hypoxia-protective effects of epidermal growth factor receptor inhibition by maintaining adenosine triphosphate levels. These in vitro experiments thus challenge the current view of mTOR as a downstream target of Akt that mediates antiapoptotic stimuli. Under the conditions of the tumour microenvironment, metabolic effects of inhibition of epidermal growth factor receptor, Akt and mTOR may adversely affect outcome by protecting the hypoxic tumour cell fraction. Topics: Adenosine Triphosphate; Antibiotics, Antineoplastic; Cell Death; Cell Hypoxia; Enzyme Inhibitors; ErbB Receptors; Fas Ligand Protein; Gene Silencing; Glioma; Humans; Membrane Potential, Mitochondrial; Protein Kinases; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Tumor Cells, Cultured | 2009 |
S6K1 plays a key role in glial transformation.
The mammalian target of rapamycin (mTOR) is a nutrient and ATP sensor suggested to play an important role in tumorigenesis, particularly in the setting of PTEN loss or activated Akt/PKB. Of mTOR's two known effectors, eIF4E has been implicated in tumorigenesis, whereas the role of S6 kinase (S6K1) in transformation is less understood. To assess the contribution of S6K1 to the transformed phenotype, we pharmacologically and genetically manipulated the mTOR-S6K pathway in glioma cells and monitored its effects on growth in soft agar, a hallmark of cellular transformation, and also assessed in vivo intracranial growth. Anchorage-independent growth by HRas(V12)-transformed human astrocytes as well as by U251 and U373 human glioma cells was inhibited by pharmacologic mTOR inhibition. Similarly, short hairpin RNA-mediated suppression of mTOR also reduced anchorage-independent growth of glioma cell lines. Expression of wild-type eIF4E in rapamycin-treated E6/E7/hTert/HRas(V12) and U373 cells failed to rescue colony formation, although expression of wild-type S6K1 or rapamycin-resistant S6K1 in rapamycin-treated U373 and U251 provided partial rescue. Consistent with the latter observation, small interfering RNA-mediated suppression of S6K1 in HRas(V12)-transformed human astrocytes, U251, and U373 cells resulted in a significant loss of anchorage-independent growth. Furthermore, we found that in vivo short hairpin RNA-mediated suppression of S6K1 in HRas(V12)-transformed human astrocytes reduced intracranial tumor size, in association with reduced tumor levels of phosphorylated ribosomal protein S6. These findings implicate the mTOR-S6K pathway as a critical mediator of glial cell transformation. Topics: Animals; Astrocytes; Cell Adhesion; Cell Proliferation; Cell Transformation, Neoplastic; Colony-Forming Units Assay; Eukaryotic Initiation Factor-4E; Genes, ras; Glioma; Humans; Immunoblotting; Immunoenzyme Techniques; Immunosuppressive Agents; Lentivirus; Phosphatidylinositol 3-Kinases; Phosphorylation; Plasmids; Protein Kinases; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Rats; Rats, Nude; Ribosomal Protein S6 Kinases, 70-kDa; RNA, Small Interfering; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transfection; Tumor Cells, Cultured | 2008 |
Delta-24-RGD in combination with RAD001 induces enhanced anti-glioma effect via autophagic cell death.
Novel therapies are clearly needed for the treatment of gliomas, and strategies that involve combining oncolytic vectors with chemotherapy hold out significant hope for a more effective treatment of this malignancy. Whether chemotherapy acts directly on tumor cells by inducing cell arrest or cell death, or indirectly by blocking tumor angiogenesis, the resulting delay in tumor growth may provide the oncolytic virus with a wider window of opportunity to overcome the challenge imposed by the growth kinetics of the tumor. In this study we sought to determine whether the oncolytic adenovirus Delta-24-RGD, in combination with everolimus (RAD001), would result in an enhanced anti-glioma effect in vivo. Viability assays showed that Delta-24-RGD antitumoral activity is synergistically enhanced by combination with RAD001. Interestingly, combination treatment of Delta-24-RGD with RAD001 induced autophagy in vitro. We showed that Delta-24-RGD improved survival of tumor-bearing animals in a dose-dependent manner. A significant finding was that RAD001 enhanced the anti-glioma effect of Delta-24-RGD and resulted in the long-term survival of 80% of the experimental animals. Immunostaining of the treated tumors showed upregulation of Atg5, thereby indicating the therapeutic induction of autophagy. This is the first report showing that Delta-24-RGD plus RAD001 causes autophagic cell death, and dramatically increases long-term survival rates of glioma-bearing animals. Topics: Adenoviridae; Animals; Autophagy; Autophagy-Related Protein 5; Blotting, Western; Cell Cycle; Cell Line, Tumor; Cell Survival; Combined Modality Therapy; Everolimus; Fluorescent Antibody Technique; Glioma; Humans; Immunoblotting; Magnetic Resonance Imaging; Mice; Microtubule-Associated Proteins; Oncolytic Virotherapy; Sirolimus | 2008 |
FK506 binding protein mediates glioma cell growth and sensitivity to rapamycin treatment by regulating NF-kappaB signaling pathway.
FK506 binding protein 5 (FKBP5) belongs to a family of immunophilins named for their ability to bind immunosuppressive drugs, also known as peptidyl-prolyl cis-trans isomerases, and also with chaperones to help protein folding. Using glioma cDNA microarray analysis, we found that FKBP5 was overexpressed in glioma tumors. This finding was further validated by real-time reverse transcription-polymerase chain reaction and Western blot analysis. The roles of FKBP5 in glioma cells were then examined. We found that cell growth was suppressed after FKBP5 expression was inhibited by short interfering RNA transfection and enhanced by FKBP5 overexpression. Electrophoretic mobility shift assay showed that nuclear factor-kappa B (NF-kappaB) and DNA binding was enhanced by FKBP5 overexpression. The expression level of I-kappa B alpha and phosphorylated NF-kappaB was regulated by the expression of FKBP5. These data suggest that FKBP5 is involved in NF-kappaB pathway activation in glioma cells. In addition, FKBP5 overexpression in rapamycin-sensitive U87 cells blocked the cells' response to rapamycin treatment, whereas rapamycin-resistant glioma cells, both PTEN-positive and -negative, were synergistically sensitive to rapamycin after FKBP5 was knocked down, suggesting that the FKBP5 regulates glioma cell response to rapamycin treatment. In conclusion, our study demonstrates that FKBP5 plays an important role in glioma growth and chemoresistance through regulating signal transduction of the NF-kappaB pathway. Topics: Antibiotics, Antineoplastic; Apoptosis; Brain Neoplasms; Cell Line, Tumor; Drug Resistance, Neoplasm; Glioma; Humans; NF-kappa B; Oligonucleotide Array Sequence Analysis; Signal Transduction; Sirolimus; Tacrolimus Binding Proteins | 2008 |
Silencing mammalian target of rapamycin signaling by small interfering RNA enhances rapamycin-induced autophagy in malignant glioma cells.
The mammalian target of rapamycin (mTOR) plays a central role in regulating the proliferation of malignant glioma cells, and mTOR-specific inhibitors such as rapamycin analogs are considered as promising therapy for malignant gliomas. However, the efficacy of mTOR inhibitors alone in the treatment of patients with malignant gliomas is only modest, potentially because these agents rather than acting as mTOR kinase inhibitors instead interfere with the function of only mTOR/raptor (regulatory-associated protein of mTOR) complex and thus do not perturb all mTOR functions. The purpose of this study was to determine whether global inhibition of the mTOR molecule enhances the antitumor effect of rapamycin on malignant glioma cells. We showed that rapamycin induced autophagy and that inhibition of autophagy by small interfering RNA (siRNA) directed against autophagy-related gene Beclin 1 attenuated the cytotoxicity of rapamycin in rapamycin-sensitive tumor cells, indicating that the autophagy was a primary mediator of rapamycin's antitumor effect rather than a protective response. Exogenous expression of an mTOR mutant interfering with its kinase activity markedly enhanced the incidence of rapamycin-induced autophagy. Moreover, silencing of mTOR with siRNA augmented the inhibitory effect of rapamycin on tumor cell viability by stimulating autophagy. Importantly, not only rapamycin-sensitive malignant glioma cells with PTEN mutations but also rapamycin-resistant malignant glioma cells with wild-type PTEN were sensitized to rapamycin by mTOR siRNA. These results indicate that rapamycin-induced autophagy is one of the agent's antitumor effects and that silencing or inhibiting mTOR kinase activity could enhance the effectiveness of rapamycin. Topics: Autophagy; Base Sequence; Brain Neoplasms; Catalysis; Cell Line, Tumor; Gene Silencing; Glioma; Humans; Microscopy, Electron; Protein Kinases; PTEN Phosphohydrolase; RNA, Small Interfering; Sirolimus; TOR Serine-Threonine Kinases | 2007 |
Specific mTOR inhibitor rapamycin enhances cytotoxicity induced by alkylating agent 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) in human U251 malignant glioma cells.
Loss of the PTEN tumor suppressor gene and amplification of the epidermal growth factor receptor (EGFR), which is common in malignant gliomas, result in activation of the mammalian target of rapamycin (mTOR). Rapamycin is a highly specific inhibitor of mTOR and induces a cytostatic effect in various glioma cell lines. DNA-damaging agents such as nitrosourea are widely used in malignant glioma treatment; therefore, we investigated the effect of rapamycin on cell growth and death in combination with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU, nimustine hydrochloride) in human glioma cells. In U251 malignant glioma (U251MG) cells, we confirmed that rapamycin enhanced ACNU-induced apoptosis. We found that rapamysin inhibited ACNU-induced p21 induction, and knocking down of p21 protein by siRNA enhanced ACNU-induced apoptosis in U251MG cells. Furthermore, adenovirus-mediated over-expression of p21 protein rescued U251MG cells from apoptosis induced by ACNU and rapamycin. Finally, treatment of intracerebral U251MG xenografts with a combination of rapamycin and ACNU in vivo resulted in statistically prolonged median survival (P<0.05). These results suggest that rapamycin in combination with DNA-damaging agents may be efficacious in the treatment of malignant gliomas. Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; Drug Synergism; Glioma; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Male; Neoplasms, Experimental; Nimustine; Protein Kinases; Rats; Rats, Nude; RNA, Small Interfering; Sirolimus; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays | 2007 |
Telomere 3' overhang-specific DNA oligonucleotides induce autophagy in malignant glioma cells.
Telomere 3' overhang-specific DNA oligonucleotides (T-oligos) induce cell death in cancer cells, presumably by mimicking telomere loop disruption. Therefore, T-oligos are considered an exciting new therapeutic strategy. The purpose of this study was to elucidate how T-oligos exert antitumor effects on human malignant glioma cells in vitro and in vivo. We demonstrated that T-oligos inhibited the proliferation of malignant glioma cells through induction of nonapoptotic cell death and mitochondria hyperpolarization, whereas normal astrocytes were resistant to T-oligos. Tumor cells treated with T-oligos developed features compatible with autophagy, with development of autophagic vacuoles and conversion of an autophagy-related protein, microtubule-associated protein 1 light chain 3 from type I (cytoplasmic form) to type II (membrane form of autophagic vacuoles). A reverse-phase protein microarray analysis and Western blotting revealed that treatment with T-oligos inhibited the mammalian target of the rapamycin (mTOR) and the signal transducer and activator of transcription 3 (STAT3). Moreover, pretreatment with T-oligos significantly prolonged the survival time of mice inoculated intracranially with malignant glioma cells compared with that of untreated mice and those treated with control oligonucleotides (P=0.0065 and P=0.043, respectively). These results indicate that T-oligos stimulate the induction of nonapoptotic autophagic also known as type II programmed cell death and are thus promising in the treatment of malignant glioma. Topics: Animals; Apoptosis; Astrocytes; Autophagy; Blotting, Western; Brain Neoplasms; Cell Survival; Cells, Cultured; DNA; Female; Flow Cytometry; Glioma; Humans; Membrane Potential, Mitochondrial; Mice; Mice, Nude; Microtubule-Associated Proteins; Mitochondria; Oligonucleotides; Protein Array Analysis; Protein Kinases; Sirolimus; STAT3 Transcription Factor; Survival Rate; Telomerase; Telomere; TOR Serine-Threonine Kinases | 2007 |
Combination of the oncolytic adenovirus ICOVIR-5 with chemotherapy provides enhanced anti-glioma effect in vivo.
Novel therapies are clearly needed for gliomas, and the combination of oncolytic vectors with chemotherapy possesses a significant hope for the treatment of this malignancy. In addition, combination with chemotherapy allows for lower virus doses to achieve anticancer effect, thus resulting in lower undesirable toxicities due to viral proteins. In this work, we sought to determine whether combination of an oncolytic adenovirus ICOVIR-5, with RAD001 or temozolomide (TMZ) could result in enhanced anti-glioma effect in vivo. We assessed the in vitro cytotoxic effect and replication properties of ICOVIR-5 in combination with RAD001 or TMZ in U87 MG glioma cell line by MTT and TCID(50), respectively. Our data showed that in vitro treatment with RAD001 or TMZ not only interfered with adenovirus replication but, in addition, enhanced its oncolytic properties. To evaluate the in vivo anticancer effect, athymic mice bearing glioma xenografts (5 x 10(5) U87 MG cells/animal) received a single intratumoral injection of ICOVIR-5 (10(7) PFU/animal). RAD001 was given as a regimen of 5 mg/kg 5 days per week until the end of the experiment and TMZ was administered for 5 days at 7.5 mg/kg/mice. Of significance, combination of ICOVIR-5 with RAD001 or TMZ showed a potent anti-glioma effect in vivo, resulting in a dramatic extension of the median animal survival and in 20-40% animals becoming free of disease beyond 90 days. Topics: Adenoviridae; Animals; Antineoplastic Agents, Alkylating; Cell Line, Tumor; Dacarbazine; Everolimus; Glioma; Humans; Mice; Mice, Nude; Neoplasms, Experimental; Oncolytic Virotherapy; Sirolimus; Temozolomide | 2007 |
The combination of novel low molecular weight inhibitors of RAF (LBT613) and target of rapamycin (RAD001) decreases glioma proliferation and invasion.
Monotherapies have proven largely ineffective for the treatment of glioblastomas, suggesting that increased patient benefit may be achieved by combining therapies. Two protumorigenic pathways known to be active in glioblastoma include RAS/RAF/mitogen-activated protein kinase and phosphatidylinositol 3-kinase/AKT/target of rapamycin (TOR). We investigated the efficacy of a combination of novel low molecular weight inhibitors LBT613 and RAD001 (everolimus), which were designed to target RAF and TOR, respectively. LBT613 decreased phosphorylation of extracellular signal-regulated kinase 1 and 2, downstream effectors of RAF, in a human glioma cell line. RAD001 resulted in decreased phosphorylation of the TOR effector S6. To determine if targeting RAF and TOR activities could result in decreased protumorigenic glioma cellular behaviors, we evaluated the abilities of LBT613 and RAD001 to affect the proliferation, migration, and invasion of human glioma cells. Treatment with either LBT613 or RAD001 alone significantly decreased the proliferation of multiple human glioma cell lines. Furthermore, LBT613 and RAD001 in combination synergized to decrease glioma cell proliferation in association with G(1) cell cycle arrest. Glioma invasion is a critical contributor to tumor malignancy. The combination of LBT613 and RAD001 inhibited the invasion of human glioma cells through Matrigel to a greater degree than treatment with either drug alone. These data suggest that the combination of LBT613 and RAD001 reduces glioma cell proliferation and invasion and support examination of the combination of RAF and TOR inhibitors for the treatment of human glioblastoma patients. Topics: Annexin A5; Blotting, Western; Cell Line, Tumor; Cell Movement; Cell Proliferation; Collagen; DNA Replication; Drug Combinations; Drug Therapy, Combination; Everolimus; Flow Cytometry; Glioma; Humans; Immunosuppressive Agents; Isoquinolines; Laminin; Mitogen-Activated Protein Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinases; Proteoglycans; raf Kinases; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases | 2007 |
Perspectives in central nervous system malignancies.
Topics: Antineoplastic Agents; Central Nervous System Neoplasms; Combined Modality Therapy; Drug Therapy, Combination; ErbB Receptors; Gefitinib; Glioma; Humans; Indoles; Protein Kinase C; Protein Kinase Inhibitors; Protein Kinases; Quinazolines; Randomized Controlled Trials as Topic; Sirolimus; TOR Serine-Threonine Kinases | 2006 |
Mechanisms of action of rapamycin in gliomas.
Rapamycin has previously been shown to be efficacious against intracerebral glioma xenografts and to act in a cytostatic manner against gliomas. However, very little is known about the mechanism of action of rapamycin. The purpose of our study was to further investigate the in vitro and in vivo mechanisms of action of rapamycin, to elucidate molecular end points that may be applicable for investigation in a clinical trial, and to examine potential mechanisms of treatment failure. In the phosphatase and tensin homolog deleted from chromosome 10 (PTEN)-null glioma cell lines U-87 and D-54, but not the oligodendroglioma cell line HOG (PTEN null), doses of rapamycin at the IC50 resulted in accumulation of cells in G1, with a corresponding decrease in the fraction of cells traversing the S phase as early as 24 h after dosing. All glioma cell lines tested had markedly diminished production of vascular endothelial growth factor (VEGF) when cultured with rapamycin, even at doses below the IC50. After 48 h of exposure to rapamycin, the glioma cell lines (but not HOG cells) showed downregulation of the membrane type-1 matrix metalloproteinase (MMP) invasion molecule. In U-87 cells, MMP-2 was downregulated, and in D-54 cells, both MMP-2 and MMP-9 were downregulated after treatment with rapamycin. Treatment of established subcutaneous U-87 xenografts in vivo resulted in marked tumor regression (P < 0.05). Immunohistochemical studies of subcutaneous U-87 tumors demonstrated diminished production of VEGF in mice treated with rapamycin. Gelatin zymography showed marked reduction of MMP-2 in the mice with subcutaneous U-87 xenografts that were treated with rapamycin as compared with controls treated with phosphatebuffered saline. In contrast, treatment of established intracerebral U-87 xenografts did not result in increased median survival despite inhibition of the Akt pathway within the tumors. Also, in contrast with our findings for subcutaneous tumors, immunohistochemistry and quantitative Western blot analysis results for intracerebral U-87 xenografts indicated that there is not significant VEGF production, which suggests possible deferential regulation of the hypoxia-inducible factor 1alpha in the intracerebral compartment. These findings demonstrate that the complex operational mechanisms of rapamycin against gliomas include cytostasis, anti-VEGF, and anti-invasion activity, but these are dependent on the in vivo location of the tumor and have implications for the Topics: Animals; Antibiotics, Antineoplastic; Blotting, Western; Cell Line, Tumor; Cell Proliferation; Enzyme-Linked Immunosorbent Assay; Glioma; Humans; Immunohistochemistry; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Neoplasm Invasiveness; Neovascularization, Pathologic; Phosphoric Monoester Hydrolases; PTEN Phosphohydrolase; Sirolimus; Tumor Suppressor Proteins; Vascular Endothelial Growth Factor A | 2005 |
Proteomic analysis reveals hyperactivation of the mammalian target of rapamycin pathway in neurofibromatosis 1-associated human and mouse brain tumors.
Individuals with the tumor predisposition syndrome, neurofibromatosis 1 (NF1), are prone to development of nervous system tumors, including neurofibromas and pilocytic astrocytomas. Based on the ability of the NF1 gene product (neurofibromin) to function as a GTPase activating protein for RAS, initial biologically based therapies for NF1-associated tumors focused on the use of RAS inhibitors, but with limited clinical success. In an effort to identify additional targets for therapeutic drug design in NF1, we used an unbiased proteomic approach to uncover unanticipated intracellular signaling pathways dysregulated in Nf1-deficient astrocytes. We found that the expression of proteins involved in promoting ribosome biogenesis was increased in the absence of neurofibromin. In addition, Nf1-deficient astrocytes exhibit high levels of mammalian target of rapamycin (mTOR) pathway activation, which was inhibited by blocking K-RAS or phosphatidylinositol 3-kinase activation. This mTOR pathway hyperactivation was reflected by high levels of ribosomal S6 activation in both Nf1 mutant mouse optic nerve gliomas and in human NF1-associated pilocytic astrocytoma tumors. Moreover, inhibition of mTOR signaling in Nf1-/- astrocytes abrogated their growth advantage in culture, restoring normal proliferative rates. These results suggest that mTOR pathway inhibition may represent a logical and tractable biologically based therapy for brain tumors in NF1. Topics: Animals; Astrocytes; Brain Neoplasms; Genes, Neurofibromatosis 1; Glioma; Humans; Mice; Mice, Transgenic; Neurofibromatosis 1; Neurofibromin 1; Phosphatidylinositol 3-Kinases; Protein Kinases; Proteomics; Ribosomal Protein S6 Kinases, 90-kDa; RNA, Messenger; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases | 2005 |
Synergistic augmentation of rapamycin-induced autophagy in malignant glioma cells by phosphatidylinositol 3-kinase/protein kinase B inhibitors.
The mammalian target of rapamycin (mTOR) is a downstream effector of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway and a central modulator of cell proliferation in malignant gliomas. Therefore, the targeting of mTOR signaling is considered a promising therapy for malignant gliomas. However, the mechanisms underlying the cytotoxic effects of a selective mTOR inhibitor, rapamycin, on malignant glioma cells are poorly understood. The purpose of this study was thus to elucidate how rapamycin exerts its cytotoxic effects on malignant glioma cells. We showed that rapamycin induced autophagy but not apoptosis in rapamycin-sensitive malignant glioma U87-MG and T98G cells by inhibiting the function of mTOR. In contrast, in rapamycin-resistant U373-MG cells, the inhibitory effect of rapamycin was minor, although the phosphorylation of p70S6 kinase, a molecule downstream of mTOR, was remarkably inhibited. Interestingly, a PI3K inhibitor, LY294002, and an Akt inhibitor, UCN-01 (7-hydroxystaurosporine), both synergistically sensitized U87-MG and T98G cells as well as U373-MG cells to rapamycin by stimulating the induction of autophagy. Enforced expression of active Akt in tumor cells suppressed the combined effects of LY294002 or UCN-01, whereas dominant-negative Akt expression was sufficient to increase the sensitivity of tumor cells to rapamycin. These results indicate that rapamycin exerts its antitumor effect on malignant glioma cells by inducing autophagy and suggest that in malignant glioma cells a disruption of the PI3K/Akt signaling pathway could greatly enhance the effectiveness of mTOR inhibitors. Topics: Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Cell Line, Tumor; Chromones; Drug Synergism; Enzyme Inhibitors; Glioma; Humans; Morpholines; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Protein Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Sirolimus; Staurosporine; TOR Serine-Threonine Kinases | 2005 |
PWT-458, a novel pegylated-17-hydroxywortmannin, inhibits phosphatidylinositol 3-kinase signaling and suppresses growth of solid tumors.
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 | 2005 |
Inhibiting phosphoinositide 3-kinases.
Topics: Androstadienes; Animals; Antibiotics, Antineoplastic; Antineoplastic Agents; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Synergism; Drug Therapy, Combination; Glioma; Humans; Interferon alpha-2; Interferon-alpha; Mice; Mice, Nude; Neoplasm Transplantation; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Proto-Oncogene Proteins c-akt; Recombinant Proteins; Signal Transduction; Sirolimus; Transplantation, Heterologous; Xenograft Model Antitumor Assays | 2005 |
Enhanced radiation damage of tumor vasculature by mTOR inhibitors.
It is known that radiation activates the phosphoinositol-3 kinase (PI3K)/Akt pathway and that inhibition of PI3K or Akt sensitizes tumor vasculature to radiotherapy. Mammalian target of rapamycin (mTOR) is a downstream target of Akt, and we hypothesized that irradiation activates mTOR signaling in both glioma and endothelial cells (ECs) and that radiosensitization results from inhibiting mTOR signaling. mTOR inhibitors, rapamycin and RAD001 (everolimus) were found to radiosensitize vascular ECs, but failed to sensitize glioma cells as determined by clonogenic assay. Therefore, we investigated the anti-angiogenic effects of mTOR inhibitors. Increased phospho-mTOR protein was detected in irradiated human umbilical vein endothelial cells (HUVEC), but not in GL261 glioma cells. Phospho-S6, a biomarker for mTOR signaling, was also found to be induced following irradiation in HUVEC and this effect was inhibited by PI3K or mTOR inhibitors. Significant increase in cleaved caspase 3 was detected when Rad001 was combined with radiation. Endothelial tube formation was significantly diminished following treatment with rapamycin and 3 Gy of radiation. Histological sections of GL261 tumors from mice showed a greatly reduced vascular density when treated with RAD001 and radiation. Power Weighted Doppler of glioma xenografts in mice showed a significant reduction in vasculature and blood flow compared with mice treated with 3 Gy or RAD001 alone. We conclude that irradiation activates mTOR signaling in vascular endothelium and that rapamycin and RAD001 increased apoptosis of ECs in response to radiation. To the authors' best knowledge this is the first study which demonstrates that mTOR inhibitors may be a way to target the vasculature by radiosensitizing the vascular endothelium resulting in better tumor control as seen in experiments demonstrating increased tumor growth delay in mice treated with rapamycin with radiation compared with mice treat with either treatment alone. We conclude that mTOR inhibitors have increased efficacy as antiangiogenics when combined with radiation. Topics: Angiogenesis Inhibitors; Animals; Apoptosis; Blotting, Western; Cell Line, Tumor; Endothelial Cells; Everolimus; Glioma; Humans; Mice; Phosphatidylinositol 3-Kinases; Protein Kinases; Radiation Effects; Radiation-Sensitizing Agents; Sirolimus; TOR Serine-Threonine Kinases; Ultrasonography, Doppler; von Willebrand Factor | 2005 |
PTEN-induction in U251 glioma cells decreases the expression of insulin-like growth factor binding protein-2.
PTEN is a tumor suppressor gene whose loss of function is observed in approximately 40-50% of human cancers. Although insulin-like growth factor binding protein-2 (IGFBP-2) was classically described as a growth inhibitor, multiple recent reports have shown an association of overexpression and/or high serum levels of IGFBP-2 with poor prognosis of several malignancies, including gliomas. Using an inducible PTEN expression system in the PTEN-null glioma cell line U251, we demonstrate that PTEN-induction is associated with reduced proliferation, increased apoptosis, and a substantial reduction of the high levels of IGFBP-2 expression. The PTEN-induced decrease in IGFBP-2 expression could be mimicked with the PI3-kinase inhibitor LY294002, indicating that the lipid phosphatase activity of PTEN is responsible for the observed effect. However, the rapamycin analog CCI-779 did not affect IGFBP-2 expression, suggesting that the PTEN-induced decrease in IGFBP-2 expression is not attributable to decreased mTOR signalling. Recombinant human IGFBP-2 was unable to rescue U251-PTEN cells from the antiproliferative effects of PTEN, and IGFBP-2 siRNA did not affect the IGF-dependent or -independent growth of this cell line. These results suggest that the clinical data linking IGFBP-2 expression to poor prognosis may arise, at least in part, because high levels of IGFBP-2 expression correlate with loss of function of PTEN, which is well known to lead to aggressive behavior of gliomas. Our results motivate translational research regarding the relationship between IGFBP-2 expression and loss of function of PTEN. Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Chromones; Enzyme Induction; Gene Expression Regulation, Neoplastic; Glioma; Humans; Insulin-Like Growth Factor Binding Protein 2; Morpholines; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinases; PTEN Phosphohydrolase; RNA, Small Interfering; Sirolimus; TOR Serine-Threonine Kinases | 2005 |
Antitumor activity of the rapamycin analog CCI-779 in human primitive neuroectodermal tumor/medulloblastoma models as single agent and in combination chemotherapy.
We examined the cytotoxicity of the immunosuppressant agent rapamycin and its analogue CCI-779 in human brain tumor cell lines in vitro and in vivo as single agents and in combination with standard chemotherapeutic drugs. In the rapamycin-sensitive PNET/MB cell line DAOY, rapamycin exhibited additive cytotoxicity with cisplatin and with camptothecin. In vivo, CCI-779 delayed DAOY xenograft growth by 160% after 1 week and 240% after 2 weeks of systemic treatment, compared with controls. Single high-dose treatment induced 37% regression of tumor solume. Growth inhibition of DAOY xenografts was 1.3 times greater after simultaneous treatment with CCI-779 and cisplatin than after cisplatin alone. Interestingly, CCI-779 also produced growth inhibition of xenografts derived from U251 malignant glioma cells, a human cell line resistant to rapamycin in vitro. These studies suggest that the rapamycin analogue CCI-779 is an important new agent to investigate in the treatment of human brain tumors, particularly PNET/MB. Topics: Animals; Antibiotics, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Camptothecin; Cell Division; Cisplatin; Drug Synergism; Female; Glioma; Growth Inhibitors; Humans; Medulloblastoma; Mice; Mice, Nude; Neuroectodermal Tumors, Primitive; Sirolimus; Tumor Cells, Cultured; Xenograft Model Antitumor Assays | 2001 |
Protein tyrosine kinase-dependent regulation of adenylate cyclase and phosphatidylinositol 3-kinase activates the expression of glial fibrillary acidic protein upon induction of differentiation in rat c6 glioma.
Glial fibrillary acidic protein (GFAP) is expressed upon cAMP-mediated induction of differentiation of glial progenitor cells into type II astrocytes. The protein is regulated by hormones, growth factors and cytokines but the signal transduction pathways involved in the regulation of GFAP expression are largely unknown. Specific protein kinase inhibitors were used to study their effect on the expression of GFAP in rat C6 glioma cells. Herbimycin A, a selective protein tyrosine kinase inhibitor, reduced GFAP mRNA and protein expression upon cAMP analog or beta-adrenergic receptor-mediated induction of differentiation. The latter inhibitor attenuated the elevation of cAMP by adenylate cyclase and abolished the activity of phosphatidylinositol 3-kinase (PI 3-K). These data indicate that GFAP expression is regulated by protein tyrosine phosphorylations, modulating the cAMP concentration and PI 3-K activity in C6 glioma cells. Topics: Adenylyl Cyclases; Adrenergic beta-Agonists; Androstadienes; Animals; Anti-Bacterial Agents; Benzoquinones; Cell Differentiation; Chromones; Cyclic AMP; Enzyme Inhibitors; Flavonoids; Gene Expression; Glial Fibrillary Acidic Protein; Glioma; Indoles; Isoproterenol; Isoquinolines; Lactams, Macrocyclic; Maleimides; Morpholines; Phosphatidylinositol 3-Kinases; Protein-Tyrosine Kinases; Quinones; Rats; Rifabutin; Sirolimus; Sulfonamides; Tumor Cells, Cultured; Wortmannin | 2001 |
Ganglioside GM1 activates the mitogen-activated protein kinase Erk2 and p70 S6 kinase in U-1242 MG human glioma cells.
Gangliosides are implicated in the regulation of cellular proliferation as evidenced by differences in ganglioside composition associated with malignant transformation and density of cells in culture, as well as their inhibitory effects when added to cells growing in culture. Exogenously added gangliosides have a bimodal effect on proliferation in U-1242 MG glioma cells, inhibiting DNA synthesis in growing cells and stimulating it in quiescent cells. We investigated the mechanisms involved in stimulation of DNA synthesis using [3H]thymidine incorporation and immune complex kinase assays to identify responsible signal transduction pathways. Treatment of quiescent U-1242 MG cells with GM1 caused activation of the mitogen-activated protein (MAP) kinase isoform Erk2. Pretreatment with the specific MAP kinase kinase inhibitor PD98059 prevented the GM1-stimulated Erk2 activation and GM1-stimulated DNA synthesis. GM1 treatment stimulated another distinct signaling pathway leading to activation of p70 S6 kinase (p70s6k), and this was prevented by pretreatment with rapamycin. Rapamycin also inhibited GM1-stimulated DNA synthesis. Activation of both pathways and stimulation of DNA synthesis were inhibited by forskolin treatment; however, GM1 had no effect on cyclic AMP levels. Platelet-derived growth factor also activated both Erk2 and p70s6k but did not cause DNA synthesis, suggesting that GM1 may stimulate additional cascades, which also contribute to GM1-mediated DNA synthesis. Topics: Calcium-Calmodulin-Dependent Protein Kinases; Colforsin; Cyclic AMP; DNA; Enzyme Activation; Enzyme Inhibitors; Flavonoids; G(M1) Ganglioside; Glioma; Humans; Immunosuppressive Agents; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase Kinases; Mitogens; Platelet-Derived Growth Factor; Polyenes; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Ribosomal Protein S6 Kinases; Signal Transduction; Sirolimus; Tumor Cells, Cultured | 1997 |
Ro31-8220 inhibits protein kinase C to block the phorbol ester-stimulated release of choline- and ethanolamine-metabolites from C6 glioma cells: p70 S6 kinase and MAPKAP kinase-1beta do not function downstream of PKC in activating PLD.
The use of bisindolylmaleimide derivatives of staurosporine as selective inhibitors of protein kinase C (PKC) is in doubt following the report by Alessi [FEBS Lett. 402 (1997) 121-123] that Ro31-8220 and GF109203X are potent in vitro inhibitors of p70 S6 kinase and mitogen-activated protein kinase-activated protein kinase-1beta, as well as of PKC. Here we show that the phorbol ester-stimulated release of choline- and ethanolamine-metabolites from C6 glioma cells due to phospholipid hydrolysis by phospholipase D (PLD) is not inhibited by rapamycin or PD98059, specific inhibitors respectively of p70 S6 kinase and MAPKK (MEK) and thus of MAPKAP kinase-1beta but is still completely blocked by Ro31-8220. We conclude therefore that p70S6k and MAPKAP kinase-1beta as well as MAPK are not involved in signalling pathways downstream of PKC that regulate phorbol ester-stimulated phospholipid turnover and that the inhibitory action of Ro31-8220 occurs by blocking PKC which regulates at least one pathway to PLD activation. The PI-3 kinase inhibitor, wortmannin, inhibits the phorbol ester-stimulated release of ethanolamine- but not choline-metabolites from C6 cells suggesting that different PLD isoforms regulate the turnover of PtdEth and PtdCho in C6 cells. Both PLD isoforms are activated via PKC but the PtdEth-PLD is also regulated via a wortmannin-sensitive pathway. Topics: Androstadienes; Animals; Choline; Enzyme Inhibitors; Ethanolamine; Flavonoids; Glioma; Indoles; Phosphoinositide-3 Kinase Inhibitors; Phospholipase D; Polyenes; Protein Kinase C; Protein Serine-Threonine Kinases; Rats; Ribosomal Protein S6 Kinases; Ribosomal Protein S6 Kinases, 90-kDa; Sirolimus; Staurosporine; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured; Wortmannin | 1997 |
Human brain tumor xenografts in nude mice as a chemotherapy model.
Two human brain tumors which were previously established in nude mice were used to determine antitumor efficacy of various therapeutic agents. These tumors were a medulloblastoma (TE-671) and a glioma (U-251) with mass doubling times of 3.5 and 5.5 days respectively as subcutaneous implants in nude mice. Intracranial (i.c.) tumor challenge was accomplished by inoculating tissue culture-grown cells of either tumor into the right cerebral hemisphere to a depth of 3 mm. Median survival time (MST) in untreated mice with 10(5) i.c. injected TE-671 cells was approximately 30 days and 53 days in the U-251 tumor. With 2 X 10(5) U-251 tumor cells the MST was 27-31 days. Groups of mice which had been inoculated with tumor were treated with various doses and schedules of antineoplastic compounds by the i.p. route. The TE-671 tumor responded to AZQ treatment with an increase in life span (ILS) of 37% compared to untreated controls and an ILS of 30% with CCNU treatment. BCNU and PCNU were ineffective. With the U-251 tumor BCNU produced an ILS of greater than 60%, with 75% cures, greater than 112% ILS with PCNU and 49% ILS with CCNU. Neither tumor responded to procarbazine, PALA, dianhydrogalactitol, D-O-norleucine or dibromodulcitol. The U-251 tumor was treated on various schedules and doses with BCNU and found to respond well on late as well as early treatment. A new drug (rapamycin) being investigated by the NCI was found to be very effective against the U-251 tumor. This model system should prove valuable in assessing the effects of various chemotherapeutic modalities against brain tumors. Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Carmustine; Disease Models, Animal; Glioma; Humans; Medulloblastoma; Mice; Mice, Nude; Neoplasm Transplantation; Neoplasms, Experimental; Polyenes; Sirolimus; Transplantation, Heterologous | 1983 |