piperidines and lonafarnib

Topics: Antiviral Agents; Drug Therapy, Combination; Europe; Hepatitis B; Hepatitis B Surface Antigens; Hepatitis B virus; Hepatitis D; Humans; Interferon-alpha; Lipopeptides; Piperidines; Pyridines; Treatment Outcome; Viral Load; Virus Replication

Lonafarnib (Zokinvy™) is an orally active farnesyltransferase inhibitor developed by Eiger BioPharmaceuticals under license from Merck & Co. for the treatment of hepatitis D virus (HDV) infections, and progeria and progeroid laminopathies. The drug was originally discovered by Merck & Co as an investigational drug in oncology. In progeria, lonafarnib inhibits farnesyltransferase to prevent farnesylation and subsequent accumulation of progerin and progerin-like proteins in the nucleus and cellular cytoskeleton. In November 2020, lonafarnib received its first approval in the USA to reduce the risk of mortality in Hutchinson-Gilford Progeria Syndrome (HGPS) and for the treatment of processing-deficient progeroid laminopathies (with either heterozygous LMNA mutation with progerin-like protein accumulation, or homozygous or compound heterozygous ZMPSTE24 mutations) in patients ≥ 12 months of age with a body surface area (BSA) of ≥ 0.39 m

Topics: Antiviral Agents; Enzyme Inhibitors; Farnesyltranstransferase; Hepatitis D; Humans; Piperidines; Progeria; Pyridines

Hutchinson-Gilford progeria syndrome (HGPS), or progeria, is an extremely rare disorder that belongs to the class of laminopathies, diseases characterized by alterations in the genes that encode for the lamin proteins or for their associated interacting proteins. In particular, progeria is caused by a point mutation in the gene that codifies for the lamin A gene. This mutation ultimately leads to the biosynthesis of a mutated version of lamin A called progerin, which accumulates abnormally in the nuclear lamina. This accumulation elicits several alterations at the nuclear, cellular, and tissue levels that are phenotypically reflected in a systemic disorder with important alterations, mainly in the cardiovascular system, bones, skin, and overall growth, which results in premature death at an average age of 14.5 years. In 2020, lonafarnib became the first (and only) FDA approved drug for treating progeria. In this context, the present review focuses on the different therapeutic strategies currently under development, with special attention to the new small molecules described in recent years, which may represent the upcoming first-in-class drugs with new mechanisms of action endowed with effectiveness not only to treat but also to cure progeria.

Topics: Aging; Aging, Premature; Cell Nucleus; Cellular Senescence; Fibroblasts; Humans; Lamin Type A; Laminopathies; Mutation; Nuclear Lamina; Phenotype; Piperidines; Progeria; Pyridines; Skin; Small Molecule Libraries

Therapy of chronic hepatitis D (CHD) is still based on interferon alpha (IFNα), introduced in clinical practice 30 years ago: results are modest and better therapies are an urgent medical need.. This article provides a critical overview of the new therapies under investigation for CHD.. Review of the recently published medical literature.. New therapeutic efforts aim to deprive the hepatitis D virus (HDV) of functions provided to its life cycle by the hepatitis B Virus (HBV) or by the host. Three therapeutic strategies are in evaluation: a) Myrcludex B, a myristolated lipopeptide of the pre-S1 domain of the HBsAg that blocks the entry of the HDV into hepatocyes and controls infection by preventing the spreading of the virus to liver cells not infected by the HBV; b) Lonafarnib, an inhibitor of a host farnesyl-transferase that hinders morphogenesis of the HDV by preventing the farnesylation of the large HD-antigen, necessary for virion assembly; c) REP 2139, a nucleic acid polymer that prevents export of the mature HDV by the presumed inhibition of the synthesis of subviral HBsAg particles with which the virion is coated. Myrcludex B and Lonafarnib increase therapeutic efficacy in combination with Peg-IFNα. In a pilot study, REP 2139 in combination with Peg-IFNα induced the clearance of serum HDV RNA and of the HBsAg in about half of 12 treated patients.. Long-term therapies with either Myrcludex B or Lonafarnib in combination with Peg-IFNα are required to achieve clinical control of CHD. However, with prolonged therapies tolerance becomes a problem; studies are on the way to determine whether Peg-IFN lambda may be better tolerated that Peg-IFNα. The promising preliminary data of REP 2139 in combination with Peg-IFNα await confirmation of the original pilot study.

Topics: Antiviral Agents; Drug Development; Drug Synergism; Hepatitis D, Chronic; Hepatitis Delta Virus; Humans; Interferon-alpha; Lipopeptides; Nucleic Acids; Piperidines; Polymers; Pyridines

The tyrosine kinase inhibitors (TKIs) have revolutionized the management of chronic myeloid leukemia (CML) and BCR-ABL1 inhibitors form the mainstay of CML treatment. Although patients with CML generally do well under TKI therapy, there is a subgroup of patients who are resistant and/or intolerant to TKIs. In these group of patients, there is the need of additional treatment strategies. In this review, we provide an update on the current knowledge of these novel treatment approaches that can be used alone and/or in combination with TKIs.

Topics: Antineoplastic Agents; Clinical Trials as Topic; Drug Resistance, Neoplasm; Everolimus; Fusion Proteins, bcr-abl; Gene Expression; Histone Deacetylase Inhibitors; Homoharringtonine; Humans; Immunotherapy; Interferon-alpha; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Molecular Targeted Therapy; Niacinamide; Piperidines; Polyethylene Glycols; Protein Kinase Inhibitors; Pyrazoles; Pyridines; Quinolones; Recombinant Proteins

Chronic delta hepatitis is the most severe form of viral hepatitis affecting nearly 65 million people worldwide. Individuals with this devastating illness are at higher risk for developing cirrhosis and hepatocellular carcinoma. Delta virus is a defective RNA virus that requires hepatitis B surface antigen for propagation in humans. Infection can occur in the form of a co-infection with hepatitis B, which can be self-limiting,

Topics: Antiviral Agents; Coinfection; Drug Therapy, Combination; Global Burden of Disease; Hepatitis B Surface Antigens; Hepatitis B virus; Hepatitis B, Chronic; Hepatitis D, Chronic; Hepatitis Delta Virus; Humans; Interferon-alpha; Lipopeptides; Organic Anion Transporters, Sodium-Dependent; Piperidines; Pyridines; Randomized Controlled Trials as Topic; Review Literature as Topic; Superinfection; Symporters; Therapies, Investigational; Treatment Outcome; Virus Assembly; Virus Internalization

Persistent coinfection with the hepatitis B/D viruses (HDV) represents the most severe form of viral hepatitis. Hepatitis D often leads to liver cirrhosis, hepatic decompensation, and hepatocellular carcinoma. The current treatment options are limited as only pegylated interferon-alpha (PEG-IFNa) has efficacy against HDV. However, treatment response is still unsatisfactory with 25-40% HDV RNA suppression after 1-2 years. In addition, late HDV RNA relapses have been described during long-term follow-up. Fortunately, new treatment options for patients with chronic hepatitis delta are now on the horizon. The hepatocyte entry inhibitor bulevirtide (formerly myrcludex B) and the farnesyl transferase inhibitor lonafarnib are currently explored in patients with chronic hepatitis delta in Phase 3 clinical studies. The nucleic acid inhibitor REP-2139-Ca and PEG-IFN-lambda are studied in Phase 2 trials. We here summarize data on the efficacy of these new antiviral drugs and the existing safety data on the treatment of HDV infection.

Topics: Antiviral Agents; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Coinfection; Drug-Related Side Effects and Adverse Reactions; Hepatitis B, Chronic; Hepatitis D; Hepatitis Delta Virus; Humans; Interferon-alpha; Lipopeptides; Nucleic Acids; Piperidines; Polymers; Pyridines; Recurrence; Treatment Outcome

Current treatment of chronic hepatitis D viral infection with interferons is poorly tolerated and effective only in a minority of patients. Despite delta virus causing the most severe form of chronic viral hepatitis, no other treatments are available. After many years of inactivity, there is now hope for new treatment approaches for delta virus and some are likely to enter clinical practice in the near future. Four new treatment approaches are currently being evaluated in phase 2 studies. These involve the hepatocyte entry inhibitor myrcludex B, the farnesyl transferase inhibitor lonafarnib, the nucleic acid inhibitor REP 2139 Ca and pegylated interferon lambda. Results obtained so far are promising, and phase 3 studies are expected shortly. This review summarizes the available data on the efficacy and safety of these new drugs.

Topics: Antiviral Agents; Clinical Trials as Topic; Hepatitis D; Hepatitis Delta Virus; Humans; Interferon-alpha; Interleukins; Lipopeptides; Nucleic Acids; Piperidines; Polyethylene Glycols; Polymers; Pyridines

Chronic hepatitis delta represents the most severe form of chronic viral hepatitis. The current treatment of hepatitis delta virus (HDV) infection consists of the use of interferons and is largely unsatisfactory. Several new compounds are currently in development for the treatment of HDV infection. However, surrogate markers that can be used to develop clinical endpoints in HDV infection are not well defined. In the current manuscript, we aimed to evaluate the existing data on treatment of HDV infection and to suggest treatment goals (possible "trial endpoints") that could be used across different clinical trials.

Topics: Biomarkers; Clinical Trials as Topic; Hepatitis B Surface Antigens; Hepatitis D, Chronic; Humans; Lipopeptides; Liver; Nucleic Acids; Piperidines; Polymers; Pyridines; RNA, Viral; Treatment Outcome

Hutchinson-Gilford progeria syndrome (HGPS) is an ultrarare and fatal disease with features of premature aging and cardiovascular diseases (atherosclerosis, myocardial infarction, and stroke). Several landmark studies in 2018-2019 have revealed novel mechanisms underlying cardiovascular pathologies in HGPS, and implicate future potential therapies for HGPS, and possibly physiological aging.

Topics: Cardiovascular Diseases; Humans; Piperidines; Progeria; Pyridines

Chronic hepatitis D (CHD) results from an infection with the hepatitis B virus and hepatitis D virus (HDV). CHD is the most severe form of human viral hepatitis. Current treatment options consist of interferon alfa, which is effective only in a minority of patients. Study of HDV molecular virology has resulted in new approaches entering clinical trials, with phase-3 studies the most advanced. These include the entry inhibitor bulevirtide, the nucleic acid polymer REP 2139-Ca, the farnesyltransferase inhibitor lonafarnib, and pegylated interferon lambda. This article summarizes the available data on these emerging therapeutics.

Topics: Antiviral Agents; Clinical Trials, Phase III as Topic; Coinfection; Drugs, Investigational; Female; Hepatitis B virus; Hepatitis B, Chronic; Hepatitis D, Chronic; Hepatitis Delta Virus; Humans; Interferon-alpha; Male; Piperidines; Polyethylene Glycols; Prognosis; Pyridines; Recombinant Proteins; Risk Assessment; Treatment Outcome

Hepatitis delta virus (HDV) causes the most severe form of human viral hepatitis and is associated with a higher risk of cirrhosis, liver decompensation and liver cancer. Interferon alpha is the only agent that has demonstrated efficacy to date, although response rates are low and it is associated with significant side effects. A better understanding of the relevant molecular virology has resulted in the identification of new candidate targets. Future therapeutic options are rapidly evolving as several new agents have entered clinical development, including the entry inhibitor myrcludex-B, the nucleic acid polymer REP2139-Ca inhibiting HBV surface antigen secretion, the farnesyltransferase inhibitor lonafarnib that targets virus assembly, and a better tolerated interferon-interferon lambda.

Topics: Animals; Antiviral Agents; Hepatitis B; Hepatitis B virus; Hepatitis D; Hepatitis D, Chronic; Hepatitis Delta Virus; Humans; Interferon-alpha; Lipopeptides; Liver Cirrhosis; Liver Neoplasms; Mice; Piperidines; Pyridines

Treatment of chronic hepatitis D still relies on Interferon. To improve efficacy, new therapeutic strategies are in development which aim to deprive the Hepatitis D Virus (HDV) of functions of the Hepatitis B Virus and of the host required for its life-cycle. Areas covered: The therapeutic options are; 1) The inhibition of the farnesylation of the large HD-protein permissive of virion assembly with Lonafarnib, 2) The blocking of HBsAg entry into cells with Myrcludex B via the inhibition of the Sodium Taurocholate Cotransporting Receptor, to prevent the spreading of HDV to uninfected hepatocytes, 3) The reduction of subviral HBsAg particles by REP 2139, leading to diminished virion morphogenesis . Expert opinion: Lonafarnib and Myrcludex reduced serum HVD-RNA; neither diminished serum HBsAg. NAP REP-2139 diminished both HDV-RNA and HBsAg in serum; a full report is awaited. In combination with Peg-Interferon, these new drugs may provide additional efficacy.

Topics: Animals; Antiviral Agents; Drug Design; Drug Therapy, Combination; Drugs, Investigational; Hepatitis B virus; Hepatitis D, Chronic; Hepatitis Delta Virus; Humans; Interferons; Lipopeptides; Piperidines; Pyridines

Viral liver diseases are frequent comorbidities and major contributors to death in HIV-positive individuals on antiretroviral therapy. Although cure of hepatitis C and control of hepatitis B with antivirals avert liver disease progression in most HIV-coinfected patients, the lack of satisfactory treatment for hepatitis delta virus (HDV) infection remains a major threat for developing cirrhosis and liver cancer in this population. In the European Union (EU) and North America, sexual contact has replaced injection drug use that has been the major transmission route for HDV in HIV-positive persons. PegIFNα is the only approved HDV therapy; however, sustained HDV-RNA clearance is achieved by less than 25%. The recent discovery of sodium taurocholate cotransporting polypeptide as the key hepatitis B virus (HBV) and HDV cell entry receptor has opened the door to a new therapeutic era. Indeed, promising results have been released using Myrcludex-B, a sodium taurocholate cotransporting polypeptide inhibitor. More encouraging are data with new classes of HDV blockers, such as prenylation inhibitors (i.e. lonafarnib) and nucleic acid polymers. At this time, sustained suppression of HDV replication is the primary goal of HDV therapy, as it is associated with normalization of liver enzymes and histological improvement. Of note, the use of specific antivirals for HDV must be given along with anti-HBV agents to prevent HBV rebounds following removal of viral interference. The lack of persistent forms of HDV-RNA could provide a unique opportunity for curing hepatitis delta, even without eliminating HBV circular covalently closed DNA. Ultimately, suppression of HDV replication along with hepatitis B surface antigen clearance once drugs are off would be the best reflect of hepatitis delta cure.

Topics: Antiviral Agents; Disease Transmission, Infectious; Hepatitis D, Chronic; HIV Infections; Humans; Interferon-alpha; Lipopeptides; Liver Cirrhosis; Liver Neoplasms; Piperidines; Pyridines; Sustained Virologic Response

Chronic hepatitis D is the most severe form of viral hepatitis, affecting ∼20 million HBV-infected people worldwide. The causative agent, hepatitis delta virus (HDV), is a unique human pathogen: it is the smallest known virus; it depends on HBV to disseminate its viroid-like RNA; it encodes only one protein (HDAg), which has both structural and regulatory functions; and it replicates using predominantly host proteins. The failure of HBV-specific nucleoside analogues to suppress the HBV helper function, and the limitations of experimental systems to study the HDV life cycle, have impeded the development of HDV-specific drugs. Thus, the only clinical regimen for HDV is IFNα, which shows some efficacy but long-term virological responses are rare. Insights into the receptor-mediated entry of HDV, and the observation that HDV assembly requires farnesyltransferase, have enabled novel therapeutic strategies to be developed. Interference with entry, for example through blockade of the HBV-HDV-specific receptor sodium/taurocholate cotransporting polypeptide NTCP by Myrcludex B, and inhibition of assembly by blockade of farnesyltransferase using lonafarnib or nucleic acid polymers such as REP 2139-Ca, have shown promising results in phase II studies. In this Review, we summarize our knowledge of HDV epidemiology, pathogenesis and molecular biology, with a particular emphasis on possible future developments.

Topics: Animals; Antiviral Agents; Cells, Cultured; Disease Models, Animal; Hepatitis D, Chronic; Hepatitis Delta Virus; Host-Pathogen Interactions; Humans; Interferon-alpha; Lipopeptides; Nucleic Acids; Piperidines; Pyridines; Virus Replication

Progeria is characterized by clinical features that mimic premature ageing. Although the mutation responsible for this syndrome has been deciphered, the mechanism of its action remains elusive. Progeria research has gained momentum particularly in the last two decades because of the possibility of revealing evidences about the ageing process in normal and other pathophysiological conditions. Various experimental models, both in vivo and in vitro, have been developed in an effort to understand the cellular and molecular basis of a number of clinically heterogeneous rare genetic disorders that come under the umbrella of progeroid syndromes (PSs). As per the latest clinical trial reports, Lonafarnib, a farnesyltranferase inhibitor, is a potent 'drug of hope' for Hutchinson-Gilford progeria syndrome (HGPS) and has been successful in facilitating weight gain and improving cardiovascular and skeletal pathologies in progeroid children. This can be considered as the dawn of a new era in progeria research and thus, an apt time to review the research developments in this area highlighting the molecular aspects, experimental models, promising drugs in trial and their implications to gain a better understanding of PSs.

Topics: Aging; Child; Clinical Trials as Topic; Humans; Lamin Type A; Longevity; Mutation; Piperidines; Prenylation; Progeria; Pyridines; Rare Diseases

Farnesyltransferase inhibitors (FTIs) have mainly been used in cancer therapy. However, more recently, investigations on these inhibitors revealed that FTIs can be used for the treatment of other diseases such as Progeria, P. falciparum resistant malaria, Trypnosomatid, etc. Hence the development of novel FTIs is an important task for the drug discovery program. Initially, numerous peptidomimetic FTIs were developed from the template of CAAX (CVIM was the first pharmacophore model used as a peptidomimetic). Later, many non-peptidomimetic FTIs have been discovered with the structural modification of the peptidomimetics. The structural analysis of those developed FTIs by various researchers suggested that the presence of a heterocycle or a polar group in place of the thiol group is required for interaction with the Zn(2+) ion. The bulky naphthyl, quinolinyl, phenyl, phenothazine, etc in this position provide better hydrophobicity to the molecules which interact with the aromatic amino acid moieties in the hydrophobic pocket. A hydrophilic region with polar groups is necessary for the polar or hydrogen bonding interactions with the amino acids or water molecules in the active site. Many FTIs have been isolated from natural products, which possessed inhibitory activity against farnesyltransferase (FTase). Among them, pepticinnamin E (9R), fusidienol (9T), gliotoxin (9V), cylindrol A (9X), etc possessed potential FTase inhibitory activities and their structural features are comparable to those of the synthetic molecules. The clinical studies progressing on FTIs showed that tipifarnib in combination with bortezomib is used for the treatment of patients with advanced acute leukemias. Successful phase I and II studies are undergoing for tipifarnib alone or in combination with other drugs/radiation for the treatment of multiple myeloma, AML, breast cancer, mantle cell lymphoma, solid tumors, non-small cell lung cancer (NSCLC), pancreatic cancer, glioblastoma, etc. Phase I pharmacokinetic (maximum tolerated dose, toxicity) and pharmacodynamic studies of AZD3409 (an orally active double prodrug) is progressing on patients with solid malignancies taking 500 mg once a day. A phase II study is undergoing on lonafarnib alone and in combination with zoledronic acid and pravastatin for the treatment of Hutchinson-Gilford Progeria syndrome (HGPS) and progeroid laminopathies. Lonafarnib therapy improved cardiovascular status of children with HGPS, by improved peripheral art

Topics: Antineoplastic Agents; Biological Products; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Neoplasms; Piperidines; Pyridines; Quantitative Structure-Activity Relationship; Quinolones

Lonafarnib is a non-peptidomimetic inhibitor of farnesyl transferase, an enzyme responsible for the post-translational lipid modification of a wide variety of cellular proteins that are involved in the pathogenic pathways of various diseases including cancer and progeria. Although extensive clinical research indicates limited activity of lonafarnib in solid tumors, there is recent interest in combinations of farnesyl transferase inhibitors with imatinib or bortezomib in hematological malignancies and to investigate the role of lonafarnib in progeria.. This review examines the in vitro and in vivo pharmacology of lonafarnib and the available clinical data for lonafarnib monotherapy and combination therapy in the treatment of solid and hematological malignancies as well as progeria, using studies identified from the PubMed database supplemented by computerized search of relevant abstracts from major cancer and hematology conferences.. There is no evidence to support the use of lonafarnib in solid tumors. There is ongoing interest to explore lonafarnib for progeria and to investigate other farnesyl transferase inhibitors for chronic and acute leukemias.

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Neoplasms; Piperidines; Progeria; Protein Prenylation; Pyridines; Treatment Outcome; Xenograft Model Antitumor Assays

Cancer is a complex disease characterized by a multitude of molecular and genetic abnormalities affecting cell proliferation and differentiation, apoptosis, and mobility (invasion). Each of these alterations represents a potential target for the development of targeted therapy. These new therapies inhibit cell growth and are said to be "cytostatic" in contrast with conventional "cytotoxic" chemotherapy. As a result of a better understanding of the molecular biology of bladder cancers, various signalling pathways involved in both carcinogenesis and tumour progression have been defined, and some of the key molecules in these pathways have been isolated and can be used as prognostic markers and as potential therapeutic targets. Locally advanced, and/or metastatic bladder cancer, is characterized by mutations of the p53 and retinoblastoma (Rb) genes, regulators of the cell cycle, which interact with the Ras-mitogen activated protein kinase (MPAK) transduction pathway. Overexpression of tyrosine kinase receptors, including EGFR, VEFGR and HER2/neu, is correlated with tumour progression and activation of the phosphatidyl-inositol-3 kinase (PI-3K) pathway is involved in tumour invasion and inhibition of apoptosis. Due to their molecular heterogeneity, optimal targeted therapy of bladder cancers will require the combined use of several molecules. Modulation of signalling pathways by these new molecules can restore chemosensitivity to cytotoxic drugs, which can then be associated with targeted therapy.

Topics: Angiogenesis Inhibitors; Antibiotics, Antineoplastic; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Bevacizumab; Disease Progression; Erlotinib Hydrochloride; Gefitinib; Genetic Therapy; Humans; Immunosuppressive Agents; Mutation; Piperidines; Protein Kinase Inhibitors; Pyridines; Quinazolines; Randomized Controlled Trials as Topic; Signal Transduction; Sirolimus; Targeted Gene Repair; Trastuzumab; Urinary Bladder Neoplasms

Farnesyltransferase inhibitors (FTIs) inhibit certain cellular signal transduction pathways, and are being evaluated for activity in hematologic malignancies. Tipifarnib and lonafarnib are orally available FTIs that are active against a variety of targets and inhibit several pathways involved in the pathogenesis of hematologic malignancies. FTIs have demonstrated activity in a variety of hematologic diseases, including acute myeloid leukemia, myelodysplastic syndrome, chronic myeloid leukemia, and multiple myeloma. This article reviews the clinical experience with tipifarnib and lonafarnib in the treatment of hematologic malignancies.

Topics: Antineoplastic Agents; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Hematologic Neoplasms; Humans; Piperidines; Pyridines; Quinolones; Signal Transduction

The farnesyltransferase inhibitors (FTIs) are in active clinical development in a variety of human malignancies. The most promising activity to date has been demonstrated in patients with hematologic malignancies, in particular acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In patients with MDS, two nonpeptidomimetic agents, tipifarnib (Zarnestra, Johnson & Johnson, New Brunswick, NJ) and lonafarnib (Sarasar, Schering-Plough, Kenilworth, NJ) have been the most extensively studied. In both phase I and phase II trials, tipifarnib has demonstrated significant efficacy, with overall response rates of 30% and complete remissions in about 15%. Dose-limiting adverse effects have been primarily myelosuppression, although fatigue, neurotoxicity, and occasional renal dysfunction have required dose reductions. Lonafarnib in patients with MDS has also resulted in clinical responses in approximately 30%, including significant improvements in platelet counts. Lonafarnib has been associated primarily with diarrhea and other gastrointestinal toxicity, anorexia, and nausea, which has limited its efficacy. Clinical response correlation with documentation of inhibition of farnesyltransferase and/or evidence of decreased farnesylation of downstream protein targets has not been demonstrated with either agent. In addition, the presence of an activating Ras mutation has not predicted response to therapy with FTIs in MDS and AML. Despite this lack of evidence, significant clinical efficacy of the FTIs has been observed in MDS, on a par with the efficacy of currently available chemotherapeutic agents, leading to further development of this new class of drugs in MDS and AML.

Topics: Adult; Aged; Antineoplastic Agents; Bone Marrow Diseases; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Disease Progression; Farnesyltranstransferase; Gastrointestinal Diseases; Genes, ras; Hematologic Neoplasms; Humans; Middle Aged; Myelodysplastic Syndromes; Piperidines; Prenylation; Protein Processing, Post-Translational; Pyridines; Quinolones; Treatment Outcome

The ras family of proto-oncogenes are upstream mediators of several essential cellular signal transduction pathways involved in cell proliferation and survival. Point mutations of ras oncogenes result in constitutive activation of oncogenic Ras. The key step in post-translational processing of Ras protein is farnesylation by farnesyl transferase. Inhibitors of this enzyme were developed initially as a therapeutic strategy for Ras-mutated tumors. Moreover, it is now clear that farnesyl transferase inhibitors (FTIs) have activity independent of Ras, and show some effects on tumors without oncogenic ras mutations. Preclinical data show that FTIs can inhibit proliferation of breast cancer cells in vitro and in vivo, and phase II studies of FTI-R115777 in advanced breast cancer show encouraging results. Therefore, FTIs, used alone or with other agents, may be a novel therapeutic approach for breast cancer.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Proliferation; Enzyme Inhibitors; Farnesyltranstransferase; Female; Genes, ras; Humans; Piperidines; Protein Prenylation; Pyridines; Quinolones; ras Proteins

Farnesyl transferase inhibitors (FTIs) are anticancer agents that were designed to block the post-translational attachment of the prenyl moiety to C-terminal cysteine residue of Ras and thus inactivate it. Because Ras plays an important role in tumour progression and the ras mutation is one of the most frequent aberrations in cancer, FTIs have been expected to exert excellent therapeutic activities. Phase I and II clinical trials confirmed relevant antitumour activity and low toxicity; however, no improvement in overall survival has been reported in Phase III trials. The exact mechanism of action of this class of agents is currently unknown. Increasing lines of evidence indicate that the cytotoxic actions of FTIs are not due to the inhibition of Ras proteins exclusively, but to the modulation of other targets, including RhoB, the centromere-binding proteins and other proteins that have not yet been identified. This review describes the pharmacological and clinical data as well as mechanisms of action of FTIs, especially lonafarnib (SCH-66336), a non-peptidomimetic inhibitor that has shown anticancer activity.

Topics: Animals; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; Colorectal Neoplasms; Drug Administration Schedule; Drug Evaluation, Preclinical; Drug Therapy, Combination; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Leukemia; Lung Neoplasms; Piperidines; Pyridines; Randomized Controlled Trials as Topic

Farnesyltransferase inhibitors (FTIs) are small-molecule inhibitors that selectivly inhibit farnesylation of a number of intracellular substrate proteins such as Ras. Preclinical work has revealed their ability to effectively inhibit tumor growth in vitro and in vivo in animal models across a wide range of malignant phenotypes. Acute myeloid leukemias (AMLs) are appropriate disease targets in that they express relevant biologic targets such as Ras, MEK, AKT, and others that may depend upon farnesyl protein transferase activity to promote cell proliferation and survival. Indeed, different intracellular proteins are substrates for prenylation. Interruption of prenylation may prevent substrates from undergoing maturation which may result in the inhibition of cellular events that depend on the function of those substrates. Phase I trials in AML and myelodysplasia have demonstrated biologic and clinical activities as determined by target enzyme inhibition, low toxicity, and both complete and partial responses. As a result, phase II trials have been initiated in order to further validate clinical activity and to identify downstream signal transduction targets that may be modified by these agents. It is anticipated that these studies will serve to define the optimal roles of FTIs in patients with these hematologic malignancies and provide insight into effective methods by which to combine FTIs with other agents.

Topics: Alkyl and Aryl Transferases; Benzodiazepines; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Drug Resistance, Neoplasm; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Imidazoles; Leukemia, Myeloid, Acute; Mitogen-Activated Protein Kinase 1; Myeloproliferative Disorders; Piperidines; Protein Prenylation; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Pyridines; Quinolones; ras Proteins; rho GTP-Binding Proteins

Cell proliferation, differentiation, and survival are regulated by a number of extracellular hormones, growth factors, and cytokines in complex organisms. The transduction of the signals by these factors from the outside to the nucleus often requires the presence of small intracellular proteins (i.e. ras and other small G proteins) that are linked to the plasma membrane through a isoprenyl residue that functions as hydrophobic anchor. Isoprenylation is a complex process regulated by different enzymatic steps that could represent potential molecular targets for anti-cancer strategies. In the present paper the different transduction pathways regulated by some isoprenylated proteins such as ras and other small G proteins are described. Moreover, the molecular mechanisms of the isoprenylation process and the mode of action of the different isoprenylation inhibitors are discussed with attention to statins, farnesyltransferase inhibitors (FTI) and aminobisphosphonates. The role of different candidate targets in the determination of anti-tumour effects by FTIs is also described in order to define potential molecular markers predictor of clinical response. On the basis of several preclinical data, new strategies based on multi-step enzyme inhibition or on target prioritization are proposed in order to enhance the anti-tumour activity of agents inhibiting isoprenylation. Finally, a summary of the principal data on clinical trials based on the use of FTIs and statins is given. In conclusion, the inhibition of isoprenylation is an attractive, but still not completely investigated therapeutic alternative that requires optimization for the translation in the current treatment of neoplasms.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Benzodiazepines; Farnesyltranstransferase; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Imidazoles; Mevalonic Acid; Neoplasms; Phosphatidylinositol 3-Kinases; Piperidines; Protein Prenylation; Protein Processing, Post-Translational; Pyridines; Quinolones; ras Proteins

The farnesyltransferase inhibitors (FTIs) are in active clinical development in a variety of human malignancies. The most promising activity to date has been demonstrated in patients with hematological malignancies, in particular acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In patients with MDS, two non-peptidomimetic agents, tipifarnib (Zarnestra, Johnson & Johnson, New Brunswick, NJ) and lonafarnib (Sarasar, Schering-Plough, Kenilworth, NJ) have been the most extensively studied. In both phase I and phase II trials, tipifarnib has demonstrated significant efficacy with overall response rates of 30%, with complete remissions in about 15%. Dose-limiting side effects have been primarily myelosuppression, although fatigue, neurotoxicity, and occasional renal dysfunction have required dose reductions. Lonafarnib in patients with MDS has also resulted in clinical responses in approximately 30%, including significant improvements in platelet counts. Lonafarnib has been associated with primarily diarrhea and other gastrointestinal toxicity, anorexia, and nausea, which has limited its efficacy. Clinical response correlation with documentation of inhibition of farnesyltransferase and/or evidence of decreased farnesylation of downstream protein targets has not been demonstrated with either agent. In addition, the presence of an activating Ras mutation has not predicted response to therapy with FTIs in MDS and AML. Despite this, significant clinical efficacy of the FTIs in MDS, on par with that of currently available chemotherapeutic agents, has been observed, leading to further development of this new class of drugs in MDS and AML.

Topics: Acute Disease; Aged; Alkyl and Aryl Transferases; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Disease Progression; Enzyme Inhibitors; Farnesyltranstransferase; Genes, ras; Hematologic Neoplasms; Humans; Leukemia, Myeloid; Middle Aged; Myelodysplastic Syndromes; Piperidines; Protein Prenylation; Protein Processing, Post-Translational; Proto-Oncogene Proteins p21(ras); Pyridines; Quinolones; Remission Induction; Signal Transduction; Treatment Outcome

Farnesyl transferase inhibitors are a new class of biologically active anticancer drugs. The exact mechanism of action of this class of agents is, however, currently unknown. The drugs inhibit farnesylation of a wide range of target proteins, including Ras. It is thought that these agents block Ras activation through inhibition of the enzyme farnesyl transferase, ultimately resulting in cell growth arrest. In preclinical models, the farnesyl transferase inhibitors showed great potency against tumor cells; yet in clinical studies, their activity was far less than anticipated. Reasons for this disappointing clinical outcome might be found in the drug-development process. In this paper, we outline an algorithm that is potentially useful for the development of biologically active anticancer drugs. The development of farnesyl transferase inhibitors, from discovery to clinical trials, is reviewed on the basis of this algorithm. We found that two important steps of this algorithm were underestimated. First, understanding of the molecular biology of the defective pathway has mainly been focused on H-Ras activation, whereas activation of K-Ras or other farnesylated proteins is probably more important in tumorigenesis. Inhibition of farnesylation is possibly not sufficient, because geranylgeranylation might activate K-Ras and suppress the effect of farnesyl transferase inhibitors. Furthermore, a well-defined proof of concept in preclinical and clinical studies has not been achieved. Integrating the proposed algorithm in future studies of newly developed biologically active anti-cancer drugs might increase the rate of success of these compounds in patients.

Topics: Animals; Antineoplastic Agents; Benzodiazepines; Clinical Trials as Topic; Drug Design; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Imidazoles; Piperidines; Pyridines; Quinolones; ras Proteins

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

Topics: Animals; Benzamides; Chromosome Aberrations; Drug Resistance, Neoplasm; Fusion Proteins, bcr-abl; Hematopoietic Stem Cell Transplantation; Humans; Imatinib Mesylate; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Piperazines; Piperidines; Pyridines; Pyrimidines; Quinolones; Randomized Controlled Trials as Topic; Thionucleotides

Cancer of the head and neck is an important medical problem, with approximately 46,500 cases predicted in the United States alone in 2003. Worldwide, more than 600,000 cases are anticipated. While several different histologic subtypes of head and neck cancer are seen in different parts of the world, more than 90% of tumors diagnosed in the United States are squamous cell carcinomas. Major strides in the management of this disease have been made in the last decade. These include, but are not limited to, the evolution of organ preservation, the increasingly well recognized role of concurrent chemoradiation therapy as either definitive therapy for unresectable disease or adjuvant therapy for high-risk surgical disease, and significant improvements in cytotoxic chemotherapy. The role of chemotherapy in this disease has been a subject of debate. Chemotherapy is now routinely included in the multimodality treatment of unresectable disease of the oral pharynx, larynx, and oral cavity. There is now increasing evidence supporting the role of induction chemotherapy in head and neck cancer. As intensified chemotherapy and radiation therapy have improved local control, the increasing incidence of distant metastases has necessitated the need for enhanced systemic control. These approaches are the topics of extensive investigations.

Topics: Adenoviridae; Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Anticarcinogenic Agents; Antineoplastic Agents; Carcinoma, Squamous Cell; Cetuximab; Clinical Trials as Topic; Combined Modality Therapy; ErbB Receptors; Genes, p53; Head and Neck Neoplasms; Humans; Piperidines; Pyridines; ras Proteins; Viral Vaccines

Farnesyl transferase inhibitors (FTIs) are a novel class of anti-cancer agents that competitively inhibit farnesyl protein transferase (FTase). Initially developed to inhibit the prenylation necessary for Ras activation, their mechanism of action seems to be more complex, involving other proteins unrelated to Ras. FTIs have been developed and tested across a wide range of human cancers. At least 3 agents within this family have been investigated in hematologic malignancies. These are tipifarnib (R115777, Zarnestra), lonafarnib (SCH66336, Sarasar), both of which are orally administered, and BMS-214662, which is given intravenously. Preliminary results from clinical trials demonstrate enzyme target inhibition, a favorable toxicity profile and promising efficacy. Ongoing studies will better determine their mechanism of action and the role of combination with other agents, defining their place in the therapeutic arsenal of hematologic disorders.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Benzodiazepines; Cell Line, Tumor; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Hematologic Neoplasms; Humans; Imidazoles; Piperidines; Pyridines; Quinolones; ras Proteins; Signal Transduction

Ras mutation is observed in 20-30% of human malignancies. Ras proteins belong to the family of G-proteins, which are able to bind and hydrolyze guanosine triphosphate reversibly. They are responsible for signal transduction within cell. Ras undergoes several steps of posttranslational modification, but only farmesylation is necessary for its biologic activity. The crucial enzyme of farnesylation - farnesyltransferase (FT-ase) has become a major target for the development of new anticancer agents--farnesyltransferase inhibitors (FTI). Mutation of Ras results in the abrogation of its normal GTP-ase activity and subsequently it causes a permanent activation of Ras with uncontrolled growth and proliferation of cells. Recently published trials revealed, that FTI are highly effective in several malignant disorders, including myeloid leukemias. FTI are bioavailable after oral administration and have an acceptable toxicity profile. No enhanced myelosuppression effect was noted. It was observed, that FTI may increase cytotoxic effect of some antineoplastic drugs and radiotherapy. It seems that these agents are an interesting and promising therapeutic option for patients, who were resistant to conventional chemotherapy. The benefits of ambulatory drug administration may improve the quality of life in oncological patients. The II phase trials with FTI are under way and we hope, that these agents will find an unquestionable position in treatment of patients with malignancies.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Farnesyltranstransferase; Genes, ras; GTP-Binding Proteins; Guanosine Triphosphate; Humans; Imidazoles; Neoplasms; Piperidines; Point Mutation; Pyridines; Quinolones; Signal Transduction

Farnesylation of Ras, a protooncogene that is frequently mutated in a number of malignancies, is critical for its biologic function. This observation has led to the development of several agents that inhibit farnesyltransferase, known as farnesyltransferase inhibitors (FTIs). The antiproliferative and antitumor effects of these agents have been demonstrated in preclinical and clinical studies. Interestingly, FTI activity does not necessarily rely on ras mutational status, indicating that Ras is not the only FTI target. Clinical data suggest that FTIs, alone and in combination with other agents, have antitumor activity. Further study is needed to determine the precise mechanism of FTI antitumor activity as well as how and where FTIs will be best used clinically.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Benzodiazepines; Clinical Trials as Topic; Drug Evaluation, Preclinical; Enzyme Inhibitors; Farnesyltranstransferase; Genes, ras; Humans; Imidazoles; Piperidines; Pyridines; Quinolones

Until recently, the therapeutic treatment of breast cancer has been dominated by endocrine-based drugs (oestrogen receptor antagonists, aromatase inhibitors etc.) and conventional cytotoxics (doxorubicin, cyclophosphamide, 5-fluorouracil etc.). However, the advent of new generation signal transduction inhibitor drugs targeted against the molecular abnormalities of breast cancer (e.g., the antibody trastuzumab, directed against the cERBB2 receptor) has the promise of providing a new era of more tumour selective therapy. Inhibitors of the enzyme farnesyl transferase (FTIs) are now undergoing early-stage clinical trials, including in patients with advanced breast cancer. Although originally developed as inhibitors of RAS signal transduction pathways, it is now apparent that these drugs are better described as prenylation inhibitors; the addition of a 15-carbon prenyl or farnesyl moiety by farnesyl transferase being critical to the function of a number of proteins, including RAS. At least three FTIs are currently undergoing clinical evaluation; R115777 (tipifarnib, Zarnestra), SCH66336 (lonafarnib, Sarasar) and BMS-214662. In terms of their potential use in the chemotherapeutic treatment of advanced breast cancer, a Phase II trial of R115777 (using either continuous or intermittent twice-daily oral dosing) has demonstrated promising activity (approximately 10% partial response rate). Overall, however, the single agent activity of FTIs in various Phase II trials has been rather modest (as well as the above mentioned breast cancer trial, some responses have been seen in patients with acute and chronic myeloid leukaemias). The main dose-limiting toxicities that have been reported are myelosuppression and fatigue and neurotoxicity (with R115777). Two Phase III trials of R115777 in colorectal (versus placebo) and pancreatic (with gemcitabine versus placebo) cancer have failed to show a survival benefit. It is likely that the future clinical direction of FTIs will be as combination therapy, especially with the taxanes, where synergy has been seen in a variety of preclinical studies.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Benzodiazepines; Breast Neoplasms; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Female; Humans; Imidazoles; Piperidines; Pyridines; Quinolones; ras Proteins

Farnesyl Protein Transferase as a target for therapeutic intervention is currently under investigation in human clinical trials. Sch-66336 (sarasar), a benzocycloheptapyridyl Farnesyl Transferase Inhibitor (FTI), has been found to be effective in cellular proliferation assays and in in vivo oncology models both as a single agent and in combination with other anti-cancer agents. Clinically, early evidence is being generated that suggests efficacy in humans, particularly in patients with leukemia. Herein, we review the biology of FPT, the discovery of Sch-66336 and other benzocycloheptapyridyl FTIs, and the clinical evaluation of Sch-66336 for the treatment of leukemia and solid tumors.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Binding Sites; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Molecular Structure; Neoplasms; Piperidines; Protein Conformation; Pyridines

The proto-oncogene Ras requires localization to the intracellular surface of the cellular membrane to exert its mitogenic effects. This subcellular localization is dependent on post-translational modification of the Ras protein, which results in the covalent addition of a lipid hydrophobic moiety to the carboxy-terminal. This post-translational processing is catalyzed by the enzyme farnesyltransferase. This enzyme adds a 15-carbon farnesyl group to the sulfur atom of the cysteine residue in the carboxy-terminal end of the Ras protein. Specific inhibitors of farnesyltransferase have been generated to block the mitogenic function of Ras. These inhibitors can also prevent the post-translational modification and function of many other farnesylated proteins. These include the centromere-associated proteins CENP-E and CENP-F, RhoB and E, the nuclear lamins, and Rap2. Preclinical studies indicate that these agents have a broad spectrum of antitumor activity, blocking proliferation and inducing apoptosis. The lead compounds currently in clinical development are R115,777 and SCH66336. Clinical trials have shown that these compounds can be safely administered, with favorable therapeutic indices, allowing the administration of biologically active doses of drug. Recent phase II clinical trials in patients with metastatic breast carcinoma have shown that R115,777 has reproducible single-agent activity, with activity being predominantly seen in patients with HER2-positive disease. Studies evaluating combined signal transduction blockade with trastuzumab and R115,777 are therefore being pursued, with a phase I study indicating that full-dose R115,777 can be safely administered with full-dose trastuzumab. Efficacy studies of this combination in patients with metastatic breast carcinoma are ongoing. Taxane and farnesyltransferase inhibitor combinations are also being evaluated because preclinical studies suggest that these classes of anticancer agents may be synergistic. Randomized clinical studies investigating the clinical benefits of farnesyltransferase inhibition, with or without a taxane and trastuzumab, in patients with treatment-naive HER2-positive metastatic breast carcinoma are now warranted.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Breast Neoplasms; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Genes, ras; Humans; Piperidines; Protein Prenylation; Proto-Oncogene Mas; Pyridines; Quinolones; ras Proteins; Signal Transduction

Protein farnesylation catalysed by the enzyme farnesyl protein transferase involves the addition of a 15-carbon farnesyl group to conserved amino acid residues at the carboxyl terminus of certain proteins. Protein substrates of farnesyl transferase include several G-proteins, which are critical intermediates of cell signalling and cytoskeletal organisation such as Ras, Rho, PxF and lamins A and B. Activated Ras proteins trigger a cascade of phosphorylation events through sequential activation of the PI3 kinase/AKT pathway, which is critical for cell survival, and the Raf/Mek/Erk kinase pathway that has been implicated in cell proliferation. Ras mutations which encode for constitutively activated proteins are found in 30% of human cancers. Because farnesylation of Ras is required for its transforming and proliferative activity, the farnesyl protein transferase inhibitors were designed as anticancer agents to abrogate Ras function. However, current evidence suggests that the anticancer activity of the farnesyl transferase inhibitors may not be simply due to Ras inhibition. This review will discuss available clinical data on three of these agents that are currently undergoing clinical trials.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Benzodiazepines; Cell Division; Clinical Trials as Topic; Combined Modality Therapy; Enzyme Inhibitors; Farnesyltranstransferase; Genes, ras; Humans; Imidazoles; Neoplasms; Piperidines; Pyridines; Quinolones; Tumor Cells, Cultured

Ras genes encode proteins that activate in an intracellular signaling network controlling differentiation, proliferation and cell survival. Mutated Ras oncogenes encoding proteins that are constitutively active can induce malignancies in a variety of laboratory models. In human malignancies, Ras mutations are common, having been identified in approximately 30% of cancers. Given the importance of Ras and downstream targets Raf and MEK in the development of malignancies and their frequent expression in human cancers, it is not surprising that a variety of agents disrupting signaling through Ras and downstream proteins are under development. These agents can be broadly classified structurally as small molecules and anti-sense oligonucleotides. They can be characterized functionally as those inhibiting Ras protein expression such as the oligodeoxynucleotide ISIS 2503, those inhibiting Ras processing, in particular the farnesyl transferase inhibitors R115777, SCH 66336 and BMS 214662, and those inhibiting downstream effectors Raf, such as ISIS 5132 and MEK, which is inhibited by CI-1040. The purpose of this review is to highlight recent advances in the development of these agents.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Benzamides; Benzodiazepines; Enzyme Inhibitors; Farnesyltranstransferase; Gene Expression Regulation, Neoplastic; Genes, ras; Humans; Imidazoles; MAP Kinase Kinase Kinases; Oligonucleotides, Antisense; Phosphorothioate Oligonucleotides; Piperidines; Proto-Oncogene Proteins c-raf; Pyridines; Quinolones; Signal Transduction

Farnesyltransferase inhibitors (FTIs) belong to a group of agents originally designed to prevent membrane attachment of Ras protein by inhibiting a key step in its post-translational processing. It was thus hypothesized that FTIs would curtail the oncogenic ras-mediated proliferative and antiapoptotic signals that are activated in human tumors. Although the Ras protein is mutated in only < 5% of breast cancers, there are multiple aberrant pathways that lead to activation of wild-type ras signaling. Moreover, FTIs have consistently demonstrated efficacy in tumors regardless of their ras mutational status. Thus, the role of other protein targets in mediating the antitumor effect of FTIs is being elucidated. This article reviews current data on the use of FTIs in breast cancer.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Capecitabine; Clinical Trials as Topic; Deoxycytidine; Drug Screening Assays, Antitumor; Drug Synergism; Enzyme Inhibitors; Farnesyltranstransferase; Female; Fluorouracil; Humans; Mice; Neoplasm Proteins; Paclitaxel; Piperidines; Protein Prenylation; Protein Processing, Post-Translational; Pyridines; Quinolones; Signal Transduction; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Farnesyl protein transferase (FPT) inhibition is an interesting and promising approach to non-cytotoxic anticancer therapy. Research in this area has resulted in several orally active compounds that are currently in clinical evaluation. This review focuses on FPT inhibitors in clinical trials and concentrates on the benzocycloheptapyridine class, with details on the discovery and development of SCH 66336, currently in Phase II clinical trials.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Binding Sites; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Molecular Structure; Neoplasms; Piperidines; Protein Conformation; Pyridines

Farnesyltransferase inhibitors represent a new class of agents that target signal transduction pathways responsible for the proliferation and survival of diverse malignant cell types. Although these agents were developed to prevent a processing step necessary for membrane attachment and maturation of Ras proteins, recent studies suggest that farnesyltransferase inhibitors block the farnesylation of additional cellular polypeptides, thereby exerting antitumor effects independent of the presence of activating ras gene mutations. Clinical trials of two farnesyltransferase inhibitors--the tricyclic SCH66336 and the methylquinolone R115777--as single agents have demonstrated disease stabilization or objective responses in 10 to 15% of patients with refractory malignancies. Combinations of farnesyltransferase inhibitors with cytotoxic chemotherapies are yielding complete and partial responses in patients with advanced solid tumors. A phase I trial of R115777 in refractory and relapsed acute leukemias induced responses in 8 (32%) of 25 patients with acute myelogenous leukemia (including two complete remissions) and in two of three with chronic myelogenous leukemia in blast crisis. In patients with solid tumors, accessible normal tissues such as peripheral blood lymphocytes or, perhaps more germane to epithelial malignancies, buccal mucosa have provided surrogate tissues that allow confirmation that farnesyltransferase is inhibited in vivo at clinically achievable drug doses. In conjunction with the R115777 acute leukemia trial, serial measurements provided evidence of farnesyltransferase enzyme inhibition, interference with farnesyltransferase function ( ie, protein processing), and blockade of signal transduction pathways in leukemic bone marrow cells. Preclinical studies of farnesyltransferase inhibitor resistance and clinical trials of farnesyltransferase inhibitors in combination with other agents currently are in progress.

Topics: Alkyl and Aryl Transferases; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Leukemia; Neoplasms; Piperidines; Pyridines; Quinolones; Signal Transduction

The targeting of molecular abnormalities in neoplasms may provide an opportunity to improve the selectivity of cancer therapy. Ras mutations are a common genetic event in human cancers. Other genetic changes in tumors can signal through ras-dependent pathways as well. The targeting of ras through the inhibition of Ras protein farnesylation is one new cancer treatment strategy under clinical evaluation. Several farnesyltransferase inhibitors (FTIs) have been evaluated in phase I trials. The toxicity and maximally tolerated doses of several FTIs have been determined, and clinical trials are underway to evaluate FTIs in combination with conventional cytotoxic chemotherapy agents. Also underway are attempts to develop assays to measure the biological effects of the FTI in patients. Inhibition of farnesylation of a number of surrogate markers are currently being investigated. These efforts may provide insight into the mechanism of action of these compounds and lead to improved patient selection for clinical trials.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Benzodiazepines; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Imidazoles; Piperidines; Pyridines; Quinolones; ras Proteins

Topics: Alkyl and Aryl Transferases; Antibodies, Monoclonal; Antineoplastic Agents; Enzyme Inhibitors; Farnesyltranstransferase; Forecasting; Oligonucleotides, Antisense; Piperidines; Protein Kinase Inhibitors; Pyridines

Proof-of-concept studies demonstrated lonafarnib (LNF), a first-in-class oral prenylation inhibitor, efficacy in patients infected with HDV. The lonafarnib with ritonavir for HDV-2 (LOWR-2) study's aim was to identify optimal combination regimens of LNF + ritonavir (RTV) ± pegylated interferon alpha (PEG-IFNα) with efficacy and tolerability for longer-term dosing. Here we report the safety and efficacy at end of treatment for up to 24 weeks.. Fifty-five patients with chronic HDV were consecutively enrolled in an open-label, single-center, phase 2 dose-finding study. There were three main treatment groups: high-dose LNF (LNF ≥ 75 mg by mouth [po] twice daily [bid] + RTV) (n = 19, 12 weeks); all-oral low-dose LNF (LNF 25 or 50 mg po bid + RTV) (n = 24, 24 weeks), and combination low-dose LNF with PEG-IFNα (LNF 25 or 50 mg po bid + RTV + PEG-IFNα) (n = 12, 24 weeks). The primary endpoint, ≥2 log. LNF, boosted with low-dose RTV, is a promising all-oral therapy, and maximal efficacy is achieved with PEG-IFNα addition. The identified optimal regimens support a phase 3 study of LNF for the treatment of HDV.

Topics: Alanine Transaminase; Drug Therapy, Combination; Hepatitis D, Chronic; HIV Infections; Humans; Interferon-alpha; Piperidines; Pyridines; Ritonavir; RNA

In a proof-of-concept (POC) study, the oral prenylation inhibitor, lonafarnib (LNF), decreased hepatitis D virus (HDV) RNA during 4 weeks of treatment. Here, we explored optimal LNF regimens. Fifteen patients (five groups; 3 per group) completed dosing as follows: (1) LNF 200 mg twice-daily (BID; 12 weeks); (2) LNF 300 mg BID (12 weeks); (3) LNF 100 mg thrice-daily (5 weeks); (4) LNF 100 mg BID + pegylated interferon alfa (PEG-IFNα) 180 μg once-weekly (QW; 8 weeks); and (5) LNF 100 mg BID + ritonavir (RTV) 100 mg once-daily (QD; 8 weeks). Tolerability and efficacy were assessed. Higher LNF monotherapy doses had greater decreases in HDV viral load than achieved in the original POC study. However, this was associated with increased gastrointestinal adverse events. Addition of RTV 100 mg QD to a LNF 100 mg BID regimen yielded better antiviral responses than LNF 300 mg BID monotherapy and with less side effects. A similar improvement was observed with LNF 100 mg BID + PEG-IFNα 180 μg QW. Two of 6 patients who received 12 weeks of LNF experienced transient posttreatment alanine aminotransferase (ALT) increases resulting in HDV-RNA negativity and ALT normalization.. The cytochrome P450 3A4 inhibitor, RTV, allows a lower LNF dose to be used while achieving higher levels of postabsorption LNF, yielding better antiviral responses and tolerability. In addition, combining LNF with PEG-IFNα achieved more substantial and rapid HDV-RNA reduction, compared to historical responses with PEG-IFNα alone. Twelve weeks of LNF can result in posttreatment HDV-RNA negativity in some patients, which we speculate results from restoring favorable immune responses. These results support further development of LNF with RTV boosting and exploration of the combination of LNF with PEG-IFN. (Hepatology 2018;67:1224-1236).

Topics: Adolescent; Adult; Aged; Antiviral Agents; Dose-Response Relationship, Drug; Drug Therapy, Combination; Enzyme Inhibitors; Female; Follow-Up Studies; Hepatitis D, Chronic; Hepatitis Delta Virus; Humans; Interferon-alpha; Male; Middle Aged; Pilot Projects; Piperidines; Pyridines; Ritonavir; RNA, Viral; Treatment Outcome; Young Adult

Hutchinson-Gilford progeria syndrome is an extremely rare, fatal, segmental premature aging syndrome caused by a mutation in LMNA yielding the farnesylated aberrant protein progerin. Without progerin-specific treatment, death occurs at an average age of 14.6 years from an accelerated atherosclerosis. A previous single-arm clinical trial demonstrated that the protein farnesyltransferase inhibitor lonafarnib ameliorates some aspects of cardiovascular and bone disease. This present trial sought to further improve disease by additionally inhibiting progerin prenylation.. Thirty-seven participants with Hutchinson-Gilford progeria syndrome received pravastatin, zoledronic acid, and lonafarnib. This combination therapy was evaluated, in addition to descriptive comparisons with the prior lonafarnib monotherapy trial.. No participants withdrew because of side effects. Primary outcome success was predefined by improved per-patient rate of weight gain or carotid artery echodensity; 71.0% of participants succeeded (P<0.0001). Key cardiovascular and skeletal secondary variables were predefined. Secondary improvements included increased areal (P=0.001) and volumetric (P<0.001-0.006) bone mineral density and 1.5- to 1.8-fold increases in radial bone structure (P<0.001). Median carotid artery wall echodensity and carotid-femoral pulse wave velocity demonstrated no significant changes. Percentages of participants with carotid (5% to 50%; P=0.001) and femoral (0% to 12%; P=0.13) artery plaques and extraskeletal calcifications (34.4% to 65.6%; P=0.006) increased. Other than increased bone mineral density, no improvement rates exceeded those of the prior lonafarnib monotherapy treatment trial.. Comparisons with lonafarnib monotherapy treatment reveal additional bone mineral density benefit but likely no added cardiovascular benefit with the addition of pravastatin and zoledronic acid.. URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00879034 and NCT00916747.

Topics: Bone and Bones; Carotid Arteries; Child, Preschool; Diphosphonates; Drug Therapy, Combination; Female; Humans; Imidazoles; Infant; Male; Piperidines; Pravastatin; Progeria; Prospective Studies; Protein Prenylation; Pyridines; Zoledronic Acid

Despite promising preclinical findings regarding clinical utility of farnesyltransferase inhibitors (FTI), such as lonafarnib, success of clinical trials is limited. A multicentre AGO-OVAR-15 phase II trial reported an unfavourable effect of lonafarnib on the outcome of patients with advanced ovarian cancer. This study was performed as a genetic subgroup analysis of the AGO-OVAR-15 trial, and investigated the utility of the promoter polymorphism rs11623866 of the farnesyltransferase ß-subunit gene (FNTB) in predicting the clinical effectiveness of lonafarnib.. The influence of rs11623866 (c.-609G > C) on FNTB promoter activity was investigated by electrophoretic-mobility-shift assay, luciferase-reporter assay and RT-qPCR. A total of 57 out of 105 patients from the AGO-OVAR-15 trial, treated with carboplatin and paclitaxel ± lonafarnib, was genotyped for rs11623866 by restriction fragment length polymorphism analysis. Genotype-dependent survival analysis was performed by Kaplan-Meier analysis.. The presence of the G allele was associated with increased FNTB promoter activity compared with the C allele. An unfavourable effect of lonafarnib was limited to patients carrying a GG genotype (HRPFS 6.2, 95%CI = 2.01, 19.41, P = 0.002; HROS 9.6, 95%CI = 1.89, 48.54, P = 0.006). Median progression free survival (PFS) for patients with the GG genotype in the lonafarnib treated arm was 10 months, whereas median PFS without FTI-treatment was 40 months. Median overall survival (OS) in the lonafarnib-treated group was 19 months, whereas median OS was not reached in the untreated group.. Discrepancies between preclinical success and clinical failure may be due to the patients' genetic variability of FNTB. Therefore, our results may encourage retrospective evaluation of FNTB polymorphisms in previous FTI studies, especially those reporting positive FTI response.

Topics: Adult; Aged; Alleles; Antineoplastic Agents; Carboplatin; Farnesyltranstransferase; Female; Genetic Markers; Genotype; Humans; Kaplan-Meier Estimate; Middle Aged; Ovarian Neoplasms; Paclitaxel; Piperidines; Polymorphism, Genetic; Promoter Regions, Genetic; Protein Subunits; Pyridines; Treatment Outcome; Young Adult

Therapies for chronic hepatitis delta virus (HDV) infection are unsatisfactory. Prenylation is essential for HDV and inhibition abrogates HDV production in experimental models. In a proof-of-concept study, we aimed to assess the effect on HDV RNA levels, safety, and tolerability of the prenylation inhibitor lonafarnib in patients with chronic delta hepatitis.. In this phase 2A double-blind, randomised, placebo-controlled study, patients aged 18 years or older with chronic HDV infection were randomly assigned (3:1 in group 1 and 2:1 in group 2) to receive lonafarnib 100 mg (group 1) or lonafarnib 200 mg (group 2) twice daily for 28 days with 6 months' follow-up. Participants were randomised by random-number tables blocked in groups of four without stratification. Both groups enrolled six treatment participants and two placebo participants. Group 1 placebo patients received open-label lonafarnib as group 2 participants. The primary therapeutic endpoint was a decrease in HDV RNA viral titre in serum and the primary safety endpoint was the ability to tolerate the drug at the prescribed dose for the full 4-week duration, defined as drug discontinuation due to intolerance or grade 3/4 adverse events. This trial is registered with ClinicalTrials.gov, number NCT01495585.. Between Jan 19, 2012, and April 28, 2014, 14 patients were enrolled, of whom eight were assigned to group 1 and six were assigned to group 2. At day 28, compared with placebo, mean log HDV RNA declines from baseline were -0·73 log IU/mL in group 1 (95% CI 0·17-1·31; p=0·03) and -1·54 log IU/mL in group 2 (1·21-1·93; p<0·0001). Lonafarnib serum concentrations correlated with HDV RNA change (r(2)=0·78, p<0·0001). Model fits show that hepatitis B surface antigen (HBsAg) remained stable after a short pharmacological delay (0·75 days [SE 0·24]), lonafarnib effectiveness in blocking HDV production was greater in group 2 than in group 1 (0·952 [SE 0·06] vs 0·739 [0·05], p<0·001), and the HDV half-life was 1·62 days (0·07). There was no evidence of virological resistance. Adverse events were mainly mild to moderate with group 1 patients experiencing diarrhoea in three patients (50%) and nausea in two patients (33%) and in group 2 with all patients (100%) experiencing nausea, diarrhoea, abdominal bloating, and weight loss greater than 2 kg (mean of 4 kg). No treatment discontinuations occurred in any treatment groups.. Treatment of chronic HDV with lonafarnib significantly reduces virus levels. The decline in virus levels significantly correlated with serum drug levels, providing further evidence for the efficacy of prenylation inhibition in chronic HDV.. National Institute of Diabetes and Digestive and Kidney Diseases and National Cancer Institute, National Institutes of Health, and Eiger Biopharmaceuticals Inc.

Topics: Administration, Oral; Adult; Antiviral Agents; Double-Blind Method; Drug-Related Side Effects and Adverse Reactions; Female; Hepatitis D, Chronic; Hepatitis Delta Virus; Humans; Male; Middle Aged; Piperidines; Placebos; Plasma; Prenylation; Pyridines; RNA, Viral; Treatment Outcome; Viral Load

Lonafarnib is an oral selective farnesyltransferase inhibitor, a class of drugs which have shown activity in preclinical glioma models. Temozolomide (TMZ) is an alkylating agent that is the first-line chemotherapy for glioblastoma.. The current study combined the cytotoxic agent TMZ with the cytostatic agent lonafarnib for patients with recurrent glioblastoma to establish a maximum tolerated dose (MTD) of the combination and its preliminary efficacy. Three dose cohorts of lonafarnib were studied in the phase 1 component of the trial (100 mg twice daily [bid], 150 mg bid, and 200 bid) with dose-dense schedule of TMZ (150 mg/m² daily) administered in an alternating weekly schedule. After establishing the MTD of lonafarnib, a subsequent expansion phase 1b was undertaken to evaluate efficacy, primarily measured by 6-month progression-free survival (PFS-6).. Fifteen patients were enrolled into the phase 1 component and 20 patients into the phase 1b component. The MTD of lonafarnib in combination with TMZ was 200 mg bid. Among the patients enrolled into the study, 34 were eligible for 6-month progression evaluation and 35 patients were evaluable for time-to-progression analysis. The PFS-6 rate was 38% (95% confidence interval [CI] = 22%, 56%) and the median PFS was 3.9 months (95% CI = 2.5, 8.4). The median disease-specific survival was 13.7 months (95% CI = 8.9, 22.1). Hematologic toxicities, particularly lymphopenia, were the most common grade 3 and 4 adverse events. There were no treatment-related deaths.. These results demonstrate that TMZ can be safely combined with a farnesyltransferase inhibitor and that this regimen is active, although the current study cannot determine the relative contributions of the 2 agents or the contribution of the novel administration schedule.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Dacarbazine; Disease-Free Survival; Female; Glioblastoma; Humans; Kaplan-Meier Estimate; Male; Middle Aged; Piperidines; Pyridines; Supratentorial Neoplasms; Temozolomide

The objective of this study was to retrospectively evaluate neurologic status pre- and posttreatment with the oral farnesyltransferase inhibitor lonafarnib in children with Hutchinson-Gilford progeria syndrome (HGPS), a rare, fatal disorder of segmental premature aging that results in early death by myocardial infarction or stroke.. The primary outcome measure for intervention with lonafarnib was to assess increase over pretherapy in estimated annual rate of weight gain. In this study, neurologic signs and symptoms were compared pre- and posttreatment with lonafarnib.. Twenty-six participants were treated for a minimum of 2 years. Frequency of clinical strokes, headaches, and seizures was reduced from pretrial rates. Three patients with a history of frequent TIAs and average clinical stroke frequency of 1.75/year during the year before treatment experienced no new events during treatment. One patient with a history of stroke died due to large-vessel hemispheric stroke after 5 months on treatment. Headache prevalence and frequency were reduced. Four patients exhibited pretherapy seizures and no patients experienced recurrent or new-onset seizures.. This study provides preliminary evidence that lonafarnib therapy may improve neurologic status of children with HGPS. To address this question, we have incorporated prospective neuroimaging and neurologic assessments as measures in subsequent studies involving children with HGPS.. This study provides Class IV evidence that lonafarnib 115-150 mg/m(2) for 24 to 29 months reduces the prevalence of stroke and TIA and the prevalence and frequency of headache over the treatment period.

Topics: Adolescent; Child; Child, Preschool; Female; Humans; Male; Nervous System Diseases; Piperidines; Progeria; Pyridines; Retrospective Studies; Treatment Outcome

This phase I study was performed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety profile, recommended dose for phase II studies, the pharmacokinetics, and antitumor activity of the combination of lonafarnib (farnesyl transferase inhibitor), trastuzumab, and paclitaxel in Her2-positive advanced breast cancer.. Twenty-three patients with Her2-overexpressing breast cancer received in the first cycle paclitaxel and trastuzumab and from cycle 2 onwards lonafarnib which was added to the combination. Dose-limiting toxicity (DLT) was determined during the second cycle.. The MTD and the recommended dose for phase II trials are lonafarnib: 250 mg/day [125 mg/bi-daily (BID)] continuously, paclitaxel: 175 mg/m² 3-h infusion every 3 weeks, and trastuzumab: 4 mg/kg loading dose and 2 mg/kg/week thereafter. The most frequently observed adverse events starting from cycle 1 onwards were alopecia, myalgia, sensory neuropathy, fatigue, arthralgia, leukocytopenia, and neutropenia. From cycle 2 onwards, additional adverse events appeared, such as diarrhea, nausea, dyspepsia, vomiting, and allergy. The mean systemic exposures of both lonafarnib and paclitaxel through all dose levels were higher in the regimen with all three study medications but with no statistically significant difference. Preliminary antitumor activity (CR + PR) was observed in 58% of all patients.. Lonafarnib can be safely combined and tolerated with full doses of paclitaxel and trastuzumab in Her2-positive advanced breast cancer patients. Promising preliminary antitumor activity warrants further evaluation of lonafarnib in combination with paclitaxel and trastuzumab in Her2-positive breast cancer.

Topics: Adult; Aged; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Dose-Response Relationship, Drug; Female; Humans; Maximum Tolerated Dose; Middle Aged; Paclitaxel; Piperidines; Pyridines; Receptor, ErbB-2; Trastuzumab; Treatment Outcome

This study evaluates whether a molecular targeted therapy with the farnesyltransferase inhibitor lonafarnib added to standard chemotherapy in first-line treatment of advanced ovarian cancer (OC) could improve progression-free (PFS) and overall survival (OS).. We performed a prospective randomized phase II study to compare standard therapy carboplatin (C; AUC 5) and paclitaxel (T; 175 mg/m(2)) in primary advanced OC with or without lonafarnib (L). Lonafarnib was given in a dose of 100mg orally twice a day during chemotherapy and was increased afterwards to 200mg up to six months as a maintenance therapy.. 105 patients were recruited (53 patients were randomized to receive LTC, 52 to TC). Hematologic toxicity was similar in both arms. Grade 3 and 4 non-hematological toxicity, occurred significantly more often with LTC (23% versus 4%, p=0.005) and was associated with a higher dropout rate. PFS and OS were not significantly different among both arms. The LTC arm showed inferiority in the stratum with residual tumor of more than 1cm: median PFS was 11.5 months (95% CI: 7.4-14.2) compared with 16.4 (95% CI: 10.3-40.4) for TC (p=0.0141; HR=0.36 (95% CI: 0.15-0.84)) with median OS 20.6 months (95% CI: 13.1-31.0) and 43.4 months (95% CI: 15.7-) for the TC arm (p=0.012; HR=0.32 (95% CI: 0.13-0.8)).. The addition of lonafarnib did not improve PFS or OS. Patients with a residual tumor of more than 1cm had significantly shorter PFS and OS. Incorporation of lonafarnib into future studies for primary therapy of OC is not recommended.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Combined Chemotherapy Protocols; Carboplatin; Carcinoma, Ovarian Epithelial; Disease-Free Survival; Female; Humans; Middle Aged; Neoplasm Staging; Neoplasms, Glandular and Epithelial; Ovarian Neoplasms; Paclitaxel; Piperidines; Prospective Studies; Pyridines; Survival Analysis; Young Adult

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare, fatal, segmental premature aging syndrome caused by a mutation in LMNA that produces the farnesylated aberrant lamin A protein, progerin. This multisystem disorder causes failure to thrive and accelerated atherosclerosis leading to early death. Farnesyltransferase inhibitors have ameliorated disease phenotypes in preclinical studies. Twenty-five patients with HGPS received the farnesyltransferase inhibitor lonafarnib for a minimum of 2 y. Primary outcome success was predefined as a 50% increase over pretherapy in estimated annual rate of weight gain, or change from pretherapy weight loss to statistically significant on-study weight gain. Nine patients experienced a ≥50% increase, six experienced a ≥50% decrease, and 10 remained stable with respect to rate of weight gain. Secondary outcomes included decreases in arterial pulse wave velocity and carotid artery echodensity and increases in skeletal rigidity and sensorineural hearing within patient subgroups. All patients improved in one or more of these outcomes. Results from this clinical treatment trial for children with HGPS provide preliminary evidence that lonafarnib may improve vascular stiffness, bone structure, and audiological status.

Topics: Adolescent; Carotid Arteries; Child; Child, Preschool; Diarrhea; Dose-Response Relationship, Drug; Drug Administration Schedule; Enzyme Inhibitors; Farnesyltranstransferase; Fatigue; Female; Humans; Male; Piperidines; Progeria; Pulse Wave Analysis; Pyridines; Treatment Outcome; Vomiting; Weight Gain

This phase I study was performed to determine the safety profile, maximum tolerated dose (MTD) and biological activity of lonafarnib (SCH 66336). Single-dose and multi-dose pharmacokinetics were conducted.. Twenty-one patients with advanced solid tumors were enrolled. Each patient received single-dose administration on day 1, cycle 1 then switched to a twice daily (BID) dosing regimen on days 2-14 of a 28-day cycle; subsequent cycles continued BID dosing on days 1-14. Dose-limiting toxicity (DLT) was assessed during the cycle one; toxicity evaluation was closely monitored throughout the treatment. Radiographic scans were completed to assess tumor response. Blood and urine pharmacokinetics were evaluated on days 1 and 14 in cycle 1. SCH 66336- induced farnesylation inhibition was assessed via conversion of prelamin A to lamin in buccal mucosa.. DLT and most common adverse events were diarrhea, fatigue, nausea and anorexia. No grade 3 or 4 hematological toxicities were observed. Nineteen of 21 patients were evaluable for response; short-term stable disease was observed in 5 patients. SCH 66336 systemic exposure increased with dose; however, drug accumulation was higher than projected. Renal excretion of parent drug was negligible. Farnesyl transferase inhibition was detected at the 200 and 300 mg BID doses.. The MTD and recommended phase II dose is 200 mg BID on days 1-14 of a 28-day dosing regimen. The plasma concentration profile suggests the pharmacokinetics of SCH 66336 is dose and time dependent. Farnesyl transferase target inhibition was observed at doses of lonafarnib recommended for further study.

Topics: Adult; Aged; Alkyl and Aryl Transferases; Antineoplastic Agents; Area Under Curve; Enzyme Inhibitors; Female; Humans; Lamin Type A; Male; Maximum Tolerated Dose; Middle Aged; Mouth Mucosa; Neoplasms; Nuclear Proteins; Piperidines; Protein Precursors; Pyridines; Treatment Outcome

Lonafarnib (LNF) is a protein farnesyl transferase (FTase) inhibitor that has shown synergistic activity with taxanes in preclinical models and early stage clinical trials. Preclinical findings suggested tubulin acetylation and FTase expression levels may be important determinants of drug sensitivity that would help identify patient populations more likely to benefit from this regimen. This pilot study evaluated the biological effects of LNF and docetaxel (DTX) combination therapy in refractory solid tumors by comparing pretreatment and post-treatment tumor biopsies.. Patients with histologically confirmed locally advanced or metastatic solid malignancies refractory to standard therapies or with no effective therapies available were eligible. Patients were randomized to 1 of 4 dosing cohorts: 1) 30 mg/m², 100 mg; 2) 36 mg/m², 100 mg; 3) 30 mg/m², 150 mg; or 4) 36 mg/m², 150 mg of DTX intravenously weekly, LNF orally twice daily, respectively.. Of the 38 patients enrolled, 36 were treated, and 29 were evaluable for toxicity and response assessment. The combination of LNF and DTX was tolerated in all cohorts with the exception of a 28% incidence of grade 3/4 diarrhea, which was manageable with aggressive antidiarrheal regimens. Seven patients derived clinically meaningful benefit from this combination treatment; these patients had significantly lower basal FTase-beta mRNA expression levels than the mean study population level (P < .05). Correlation of clinical benefit with tubulin acetylation content as well as basal acetyl-tubulin content were evaluated. However, no significant correlation was found.. Despite the small number of patients, these findings support our preclinical mechanistic studies and warrant further clinical investigations using FTase-beta mRNA expression as a potential predictive biomarker to select for an enriched patient population to study the effects of taxane and FTase inhibitor combination therapies.

Topics: Adult; Antineoplastic Combined Chemotherapy Protocols; Docetaxel; Enzyme Inhibitors; Farnesyltranstransferase; Female; Humans; Male; Middle Aged; Neoplasms; Pilot Projects; Piperidines; Pyridines; Taxoids

We conducted a phase I clinical trial of the combination of SCH 66336 with temozolomide administered on the standard 5-day dosing schedule. The primary objective was to determine the maximum tolerated dose and dose limiting toxicity (DLT) of twice daily SCH 66336 when administered with temozolomide to adults with malignant glioma previously treated with radiation therapy. Patients were enrolled to two strata: stratum A, patients not on enzyme-inducing antiepileptic drugs (EIAEDs); stratum B, patients receiving EIAEDs. Temozolomide was administered at a dose of 150 mg/m(2) daily for five days for the first 28-day cycle and escalated to 200 mg/m(2), during subsequent cycles. SCH 66336 was administered twice daily on a continuous daily dosing schedule. The starting dose of SCH 66336 was 75 mg twice daily for stratum A and 125 mg twice daily for stratum B. Cohorts of 3-6 patients were treated per dose level until DLT was observed. Thirty six patients were enrolled on study, including 21 patients on stratum A and 15 on stratum B. All DLTs were grade 3 events and included hepatic, gastrointestinal, renal, thrombotic and constitutional events. No grade 4 or 5 toxicities were observed. The phase II dose of SCH 66336 when combined with temozolomide is 150 mg twice daily for patients not on EIAEDs and 175 mg twice daily for patients on EIAEDs.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Carotenoids; Dacarbazine; Disease-Free Survival; Drug Combinations; Enzyme Inhibitors; Fatty Acids, Unsaturated; Female; Glioma; Humans; Kaplan-Meier Estimate; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Grading; Piperidines; Pyridines; Temozolomide; Vitamin E

We conducted a phase I study to assess safety, pharmacokinetics, pharmacodynamics, and activity of lonafarnib plus gemcitabine. Subjects received oral lonafarnib twice daily and gemcitabine on days 1, 8, and 15 every 28 days; multiple dose levels were explored. Lonafarnib had no apparent effect on gemcitabine PK. Mean lonafarnib half-life ranged from 4 to 7 hr; median T(max) values ranged from 4 to 8 hr. Two patients had partial response; seven patients had stable disease at least 6 months. Oral lonafarnib at 150 mg a.m./100 mg p.m. plus gemcitabine at 1,000 mg/m(2) is the maximum tolerated dose with acceptable safety and tolerability.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Deoxycytidine; Dose-Response Relationship, Drug; Female; Gemcitabine; Humans; Infusions, Intravenous; Male; Middle Aged; Neoplasms; Piperidines; Pyridines

Treatment options for recurrent squamous cell carcinoma of the head and neck (SCCHN) following platinum-based therapy are limited. Lonafarnib is a potent, specific inhibitor of farnesyl transferase that demonstrated marked antitumor activity as monotherapy in treatment-naive SCCHN in a phase Ib study. A phase II study of lonafarnib was conducted to determine its efficacy and safety in patients with recurrent, platinum-refractory SCCHN.. This was an open-label, phase II, single-center study in patients with recurrent SCCHN after platinum-based therapy. A Simon 2-stage design was used, with a plan to close the study to further accrual if <2 of the first 15 patients had objective responses. Patients were treated with lonafarnib 200 mg twice daily (b.i.d.) by mouth continuously in 4-week cycles.. Fifteen patients with baseline Eastern Cooperative Oncology Group PS 0-1 and median age 57 years were enrolled. Twelve patients had received at least 2 previous chemotherapy regimens. Median duration of treatment with lonafarnib was 61 days. No objective response was observed. Seven (47%) patients maintained stable disease through >or=3 cycles of therapy. Median time to progression and survival time were 2.04 and 9.17 months, respectively. Most treatment-related toxicities were grade 1-2, and there were no treatment-related deaths.. Lonafarnib at a dose of 200 mg b.i.d. was well-tolerated. However, there were no objective responses observed in the first 15 patients enrolled in this study, and the study was closed to further accrual, as per predefined criteria. Further evaluation of lonafarnib in platinum-refractory SCCHN is not planned.

Topics: Adult; Aged; Carcinoma, Squamous Cell; Drug Resistance, Neoplasm; Female; Head and Neck Neoplasms; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Recurrence, Local; Neoplasm Staging; Piperidines; Prognosis; Pyridines; Survival Rate; Treatment Outcome

Lonafarnib is an orally bio-available farnesyltransferase inhibitor that prevents farnesylation of specific target proteins including Ras. In a multicenter study, 67 patients with advanced myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) were treated with a continuous oral dose of 200-300 mg of lonafarnib and were evaluated for hematologic, pathologic and pharmacodynamic response. The median age of patients was 70 years (range 44-86). There were 32 patients with MDS (RAEB-20 and RAEB-t-12) and 35 with CMML. Overall 16 (24%) of the patients responded with two patients achieving a complete remission and one a partial response. Responses were seen in 6/32 and 10/35 patients with MDS and CMML, respectively. Of the 19 patients who were platelet transfusion-dependent prior to treatment, 5 (26%) became transfusion-free for a median duration of 185 days. A decrease in the farnesylation of the HDJ-2 protein measured in patient-derived cells was observed in the majority of patients during treatment with lonafarnib, but no clear correlation between changes in farnesylation and clinical effect could be made. Gastrointestinal toxicity was significant with 19% of patients discontinuing therapy due to diarrhea, nausea and/or anorexia. Lonafarnib has demonstrable activity in patients with advanced MDS and CMML.

Topics: Adult; Aged; Aged, 80 and over; Drug Monitoring; Enzyme Inhibitors; Farnesyltranstransferase; Gastrointestinal Diseases; Humans; Leukemia, Myelomonocytic, Chronic; Maximum Tolerated Dose; Middle Aged; Myelodysplastic Syndromes; Piperidines; Pyridines; Remission Induction; Treatment Outcome

Although an activating mutation of Ras is commonly observed in myelodysplastic syndrome (MDS), the role of Ras in the natural history of MDS remains largely unknown. We prospectively studied efficiency and tolerance of lonafarnib, a compound able to inhibit Ras signalling pathway through an inhibition of farnesyl transferase, in patients with MDS or secondary acute myeloid leukaemia (sAML). Lonafarnib was administered orally at a dose of 200 mg twice daily for three courses of 4 weeks (separated by 1 to 4 weeks without treatment). Sixteen patients were included: FAB/RAEB (n = 10), RAEB-T (n = 2), sAML (n = 2) and chronic myelomonocytic leukaemia (CMML; n = 2); WHO/RAEB-1 (n = 4), RAEB-2 (n = 5), AML (n = 5), CMML (n = 2). Median age was 70 (53-77) years. The karyotype was complex or intermediate in 11 patients, and the International Prognostic Scoring Systems (IPSS) risk groups were low in two patients, INT-1 in one patient, INT-2 in four patients and high in six patients (unknown or not applicable in three patients). Among the 14 patients tested, five had Ras mutations in codons 12, 13 or 61 of N-Ras, K-Ras or H-Ras. One patient was excluded of the analysis for protocol violation, and 15 patients were assessable for tolerance. Gastrointestinal toxicities (diarrhoea, nausea and anorexia) and myelosuppression were the major side effects. Other toxicities included infections, fatigue, increase of liver enzymes, arrhythmia and skin rash. One patient died of infection, and the treatment was stopped in one other who developed atrial fibrillation. Doses were reduced in all but one patient treated with more than one course of farnesyl transferase inhibitor. Responses were assessable in 12 patients. A partial response in one sAML patient and a very transient decrease of blast cell count with normalisation of karyotype in one MDS patient were observed. No relation between improvement of marrow parameters and detected Ras mutations was observed. Lonafarnib alone, administered following our schedule, has shown limited activity in patients with MDS or secondary AML. Gastrointestinal and haematological toxicities appear the limiting toxicity in this population of patients.

Topics: Aged; Farnesyltranstransferase; Female; Gastrointestinal Diseases; Genes, ras; Humans; Leukemia, Myeloid, Acute; Male; Middle Aged; Myelodysplastic Syndromes; Piperidines; Pyridines

This phase I study was conducted to evaluate the safety, tolerability, pharmacological properties and biological activity of the combination of the lonafarnib, a farnesylproteintransferase (FTPase) inhibitor, with gemcitabine and cisplatin in patients with advanced solid malignancies.. This was a single institution study to determine the maximal tolerated dose (MTD) of escalating lonafarnib (75-125 mg po BID) with gemcitabine (750-1,000 mg/m(2) on days 1, 8, 15) and fixed cisplatin (75 mg/m(2) day 1) every 28 days. Due to dose-limiting toxicities (DLTs) of neutropenia and thrombocytopenia in initial patients, these patients were considered "heavily pre-treated" and the protocol was amended to limit prior therapy and re-escalate lonafarnib in "less heavily pre-treated patients" on 28-day and 21-day schedules. Cycle 1 and 2 pharmacokinetics (PK), and farnesylation of the HDJ2 chaperone protein and FPTase activity were analyzed.. Twenty-two patients received 53 courses of therapy. Nausea, vomiting, and fatigue were frequent in all patients. Severe toxicities were observed in 91% of patients: neutropenia (41%), nausea (36%), thrombocytopenia (32%), anemia (23%) and vomiting (23%). Nine patients withdrew from the study due to toxicity. DLTs of neutropenia, febrile neutropenia, thrombocytopenia, and fatigue limited dose-escalation on the 28-day schedule. The MTD was established as lonafarnib 75 mg BID, gemcitabine 750 mg/m(2) days 1, 8, 15, and cisplatin 75 mg/m(2) in heavily pre-treated patients. The MTD in the less heavily pre-treated patients could not be established on the 28-day schedule as DLTs were observed at the lowest dose level, and dose escalation was not completed on the 21-day schedule due to early study termination by the Sponsor. No PK interactions were observed. FTPase inhibition was not observed at the MTD, however HDJ-2 gel shift was observed in one patient at the 100 mg BID lonafarnib dose. Anti-cancer activity was observed: four patients had stable disease lasting >2 cycles, one subject had a complete response, and another had a partial response, both with metastatic breast cancer.. Lonafarnib 75 mg BID, gemcitabine 750 mg/m(2) days 1, 8, 15, and cisplatin 75 mg/m(2) day 1 on a 28-day schedule was established as the MTD. Lonafarnib did not demonstrate FTPase inhibition at these doses. Despite the observed efficacy, substantial toxicity and questionable contribution of anti-tumor activity of lonafarnib to gemcitabine and cisplatin limits further exploration of this combination.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Cisplatin; Deoxycytidine; Dose-Response Relationship, Drug; Farnesyltranstransferase; Fatigue; Female; Gemcitabine; HSP40 Heat-Shock Proteins; Humans; Male; Maximum Tolerated Dose; Middle Aged; Nausea; Piperidines; Pyridines; Treatment Outcome; Vomiting

To establish the maximum tolerated dose of the farnesyltransferase inhibitor lonafarnib (Sarasar, Schering-Plough Corp., Kenilworth, NJ) in combination with weekly paclitaxel in patients with solid tumors. Tolerability, pharmacokinetics, safety, and dose-limiting toxicity were characterized.. Patients were enrolled from January 2000 to May 2001. Lonafarnib was administered continuously orally twice daily at doses of 100, 125, and 150 mg in combination with paclitaxel at doses of 40, 60, or 80 mg/m(2) i.v. over 1 h weekly in 28-day cycles in a phase I design. Plasma samples for determinations of lonafarnib and paclitaxel concentrations were collected at selected time points.. Twenty-seven patients were enrolled. The maximum tolerated dose (the dose level below where dose-limiting toxicity occurred and the recommended phase II dose) was lonafarnib 125 mg/m(2) twice daily and paclitaxel 80 mg/m(2) weekly. Dose-limiting toxicity was neutropenia with or without fever, which occurred in two of three patients treated at the lonafarnib 150 mg twice daily dose level. Diarrhea was a common side effect of lonafarnib but usually was mild to moderate in severity and could be controlled with standard medication without lonafarnib dose adjustment. Other reported adverse events included nausea, vomiting, fatigue, and taste changes. These adverse events were neither more frequent nor more severe than would be expected with paclitaxel alone. There were no apparent pharmacokinetic interactions between weekly paclitaxel and continuous twice-daily lonafarnib.. The recommended dose of lonafarnib for phase II trials is 125 mg orally twice daily when combined with weekly paclitaxel 80 mg/m(2). The dose-limiting toxicity was neutropenia.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; Clinical Trials as Topic; Dose-Response Relationship, Drug; Enzyme Inhibitors; Farnesyltranstransferase; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Paclitaxel; Piperidines; Pyridines; Time Factors

Farnesyl transferase inhibitors (FTI) exhibit anticancer activity as a single agent in preclinical studies and show promise in combination with other therapeutics in clinical trials. Previous studies show that FTIs arrest cancer cells in mitosis; however, the mechanism by which this occurs is unclear. Here, we observed that treatment of various cancer cell lines with the FTI lonafarnib caused mitotic chromosomal alignment defects, leaving cells in a pseudometaphase state, whereby both aligned chromosomes and chromosomes juxtaposed to the spindle poles (termed "lagging chromosomes") were observed in the same cell. To determine how this occurs, we investigated the functionality of two farnesylated mitotic proteins, CENP-E and CENP-F, which mediate chromosomal capture and alignment. The data show that lonafarnib in proliferating cancer cells depletes CENP-E and CENP-F from metaphase but not prometaphase kinetochores. Loss of CENP-E and CENP-F metaphase localization triggered aberrant chromosomal maintenance, causing aligned chromosomes to be prematurely released from the spindle equator and become lagging chromosomes, resulting in a mitotic delay. Furthermore, lonafarnib treatment reduces sister kinetochore tension and activates the BubR1 spindle checkpoint, suggesting that farnesylation of CENP-E and CENP-F is critical for their functionality in maintaining kinetochore-microtubule interactions. Importantly, apparently similar chromosomal alignment defects were observed in head and neck tumors samples from a phase I trial with lonafarnib, providing support that lonafarnib disrupts chromosomal maintenance in human cancers. Lastly, to examine how farnesylation could regulate CENP-E in mediating kinetochore-microtubule attachments, we examined possible docking motifs of a farnesyl group on the outer surface of the microtubule. This analysis revealed three hydrophobic patches on the tubulin dimer for insertion of a farnesyl group, alluding to the possibility of an association between a farnesyl group and the microtubule.

Topics: Binding Sites; Cell Line, Tumor; Cell Proliferation; Chromosomal Proteins, Non-Histone; Chromosomes, Human; Enzyme Activation; Enzyme Inhibitors; Farnesyltranstransferase; Head and Neck Neoplasms; Humans; Kinetochores; Metaphase; Microfilament Proteins; Microtubules; Piperidines; Prometaphase; Protein Kinases; Protein Serine-Threonine Kinases; Pyridines; Spindle Apparatus

Lonafarnib is an orally bioavailable nonpetidomimetic farnesyl transferase inhibitor with significant activity against BCR-ABL-positive cell lines and primary human chronic myeloid leukemia (CML) cells. Lonafarnib can inhibit the proliferation of imatinib-resistant cells and increases imatinib-induced apoptosis in vitro in cells from imatinib-resistant patients.. The authors conducted a phase 1 study of lonafarnib in combination with imatinib in patients with CML who failed imatinib therapy. The starting dose level for patients with chronic phase (CP) disease was imatinib, 400 mg/day, plus lonafarnib at a dose of 100 mg twice daily. The starting dose levels for accelerated phase (AP) and blast phase (BP) disease were 600 mg/day and 100 mg twice daily, respectively.. A total of 23 patients were treated (9 with CP, 11 with AP, and 3 with BP) for a median of 25 weeks (range, 4-102 weeks). Of those with CP disease, 2 patients had grade 3 (according to the National Cancer Institute Common Toxicity Criteria [version 2.0]) dose-limiting toxicities (DLTs) at the 400 + 125-mg dose, including diarrhea (2 patients), vomiting (1 patient), and fatigue (1 patient). In patients with AP/BP disease, DLTs were observed at the 600 + 125-mg dose and was comprised of diarrhea (1 patient) and hypokalemia (1 patient). Eight patients (35%) responded; 3 with CP disease achieved a complete hematologic response (CHR) (2 patients) and a complete cytogenetic response (1 patient). Three patients with AP disease responded (2 CHR, 1 partial cytogenetic response), and 2 patients with BP disease demonstrated hematologic improvement. Pharmacokinetics data suggest no apparent increase in exposure or changes in the pharmacokinetics of either lonafarnib or imatinib when they are coadministered.. The results of the current study indicate that the combination of lonafarnib and imatinib is well tolerated and the maximum tolerated dose of lonafarnib is 100 mg twice daily when combined with imatinib at a dose of either 400 mg or 600 mg daily.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Diarrhea; Dose-Response Relationship, Drug; Drug Administration Schedule; Fatigue; Female; Humans; Imatinib Mesylate; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Male; Middle Aged; Piperazines; Piperidines; Pyridines; Pyrimidines; Treatment Failure; Treatment Outcome; Vomiting

A dose-escalation phase I and pharmacokinetic study of the farnesyltransferase inhibitor lonafarnib (SCH66336) was conducted in children with recurrent or progressive CNS tumors. Primary objectives were to estimate the maximum-tolerated dose (MTD) and to describe the dose-limiting toxicities (DLTs) and pharmacokinetics of lonafarnib. Farnesylation inhibition of HDJ-2 in peripheral blood was also measured.. Lonafarnib was administered orally twice daily at dose levels of 70, 90, 115, 150, and 200 mg/m2/dose bid. A modified continual reassessment method (CRM) was used to estimate the MTD based on actual dosages of lonafarnib administered and toxicities observed during the initial 4 weeks of treatment.. Fifty-three children with progressive or recurrent brain tumors were enrolled, with a median age of 12.2 years (range, 3.9 to 19.5 years). Dose-limiting pneumonitis or myelosuppression was observed in three of three patients at the 200 mg/m2/dose level. A relatively constant DLT rate at the 70, 90, and 115 mg/m2/dose levels resulted in a recommended phase II dose of 115 mg/m2/dose. Significant diarrhea did not occur with prophylactic loperamide. Both radiographic response (one anaplastic astrocytoma) and stable disease (one medulloblastoma, two high-grade and four low-grade gliomas, one ependymoma, and one sarcoma) were noted, and seven patients remained on treatment for 1 year or longer.. Although the estimated MTD by the CRM model was 98.5 mg/m2/dose, because of the relatively constant observed DLT rate at the lower four dose levels, the recommended phase II dose of lonafarnib is 115 mg/m2/dose administered twice daily by mouth with concurrent loperamide.

Topics: Administration, Oral; Adolescent; Adult; Central Nervous System Neoplasms; Child; Child, Preschool; Dose-Response Relationship, Drug; Drug Administration Schedule; Enzyme Inhibitors; Farnesyltranstransferase; Female; Follow-Up Studies; Humans; Infant; Infant, Newborn; Male; Maximum Tolerated Dose; Neoplasm Invasiveness; Neoplasm Staging; Piperidines; Pyridines; Risk Assessment; Survival Analysis; Treatment Outcome

The objective was to determine whether food affects the pharmacokinetics and safety of lonafanib, an orally bioavailable farnesyl transferase inhibitor that is under clinical evaluation for the treatment of various hematologic malignancies and solid tumors.. Two Phase 1 studies were conducted in separate patient populations. A single-dose study was performed in 12 healthy subjects who received lonafarnib 100 mg under fasted and fed conditions. Additionally, a multiple-dose study was performed in 19 patients with advanced cancer who received lonafarnib 200 mg Q 12 H for 28 days under fasted and fed conditions. Nine of the 19 patients completed both treatment cycles and were used for pharmacokinetic assessment. A 2-week washout period separated treatments in each study. Single-dose pharmacokinetics were assessed at various time points up to 48 hours postdose and multiple-dose pharmacokinetics were assessed at Day 15 for 24 hours postdose.. The pharmacokinetics of lonafarnib were affected by food during single-dose but not multiple-dose administration. Relative oral bioavailabilities (fed vs. fasted) based on log-transformed maximum plasma concentration (C(max)) and area under the concentration-time curve (AUC) were 48% and 77%, respectively, following single-dose administration, and 87% and 96%, respectively, following multiple-dose administration. Intrasubject variability in the pharmacokinetic parameters was less pronounced after multiple dosing (17%) than that after single dosing (33%) of lonafarnib. Intersubject variability was unaffected by food in either study. In the single-dose study, 7 of the 12 subjects (58%) reported treatment emergent adverse events, the most common being headache. No clinically significant differences in adverse events were seen between fasting and fed states after a single dose administration. Thus, single dose 100 mg lonafarnib was safe and generally well tolerated. In the multiple-dose study, all 19 subjects reported at least one treatment-emergent adverse event. General disorders including fatigue and anorexia, and gastrointestinal disorders including diarrhea, vomiting and nausea, were the most commonly reported adverse events after multiple doses. While gastrointestinal adverse events were reported with equal frequency under both fasting (82%, 14/17) and fed states (83%, 15/18), the incidence of severe gastrointestinal adverse events was higher in fasted (47%, 8/17) vs. fed subjects (22%, 4/18) after multiple-dose administration.. The administration of food does not affect the pharmacokinetics of lonafanib following multiple-dose administration. We recommend that multiple-dose lonafarnib should be administered with food to enhance tolerability.

Topics: Adult; Aged; Analysis of Variance; Area Under Curve; Biological Availability; Cross-Over Studies; Drug Administration Schedule; Enzyme Inhibitors; Farnesyltranstransferase; Female; Food-Drug Interactions; Humans; Male; Middle Aged; Neoplasms; Piperidines; Pyridines

Lonafarnib (SCH66336) is a nonpeptidomimetic farnesyl transferase inhibitor that has demonstrated significant preclinical activity against chronic myelogenous leukemia (CML) cells and in CML animal models.. In the current study, the efficacy of lonafarnib was investigated in patients with CML in the chronic or accelerated phase that was resistant or intolerant to imatinib. Thirteen patients with CML in the chronic (n = 6 patients) or accelerated (n = 7 patients) phase were treated with lonafarnib at a dose of 200 mg orally twice daily. Ten patients had failed therapy with imatinib and 3 patients were intolerant to imatinib. The median age of the patients was 62 years (range, 38-80 yrs) and the median time from the diagnosis of CML to therapy with lonafarnib was 5 years (range, 0.3-13 yrs). In addition to imatinib mesylate, all patients had received prior therapy with interferon-alpha and seven patients had received other treatments. The median duration of therapy with lonafarnib was 8 weeks (range, 2-41 wks).. Two patients responded. One patient in the accelerated phase of CML returned to the chronic phase, a response that lasted for 3 months. Another patient with chronic phase disease had lowering of the leukocyte count without the need for hydroxyurea and normalization of the differential count that lasted for 5 months. The most common adverse event was diarrhea, which was noted in 11 patients (84%) (Grade > or = 3 in 4 patients; 31%; toxicity was graded according to the National Cancer Institute Common Toxicity Criteria [version 2.0]). Therapy was discontinued in one patient because of diarrhea not responding to dose adjustments.. Single-agent lonafarnib appears to have clinical activity in a small proportion of patients with CML refractory to imatinib.

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Benzamides; Drug Resistance, Neoplasm; Farnesyltranstransferase; Female; Humans; Imatinib Mesylate; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Male; Middle Aged; Pilot Projects; Piperazines; Piperidines; Pyridines; Pyrimidines

The ras family of proto-oncogenes are upstream mediators of several essential cellular signal transduction pathways involved in cell proliferation and survival. Point mutations of ras oncogenes result in constitutive activation of oncogenic Ras. The key step in post-translational processing of Ras protein is farnesylation by farnesyl transferase. Inhibitors of this enzyme were developed initially as a therapeutic strategy for Ras-mutated tumors. Moreover, it is now clear that farnesyl transferase inhibitors (FTIs) have activity independent of Ras, and show some effects on tumors without oncogenic ras mutations. Preclinical data show that FTIs can inhibit proliferation of breast cancer cells in vitro and in vivo, and phase II studies of FTI-R115777 in advanced breast cancer show encouraging results. Therefore, FTIs, used alone or with other agents, may be a novel therapeutic approach for breast cancer.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Proliferation; Enzyme Inhibitors; Farnesyltranstransferase; Female; Genes, ras; Humans; Piperidines; Protein Prenylation; Pyridines; Quinolones; ras Proteins

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Farnesyltranstransferase; Humans; Leukemia, Myelomonocytic, Chronic; Leukocytosis; Male; Middle Aged; Piperidines; Pyridines; Radiography, Thoracic

In this study, the feasibility and activity of combined chemotherapy of the farnesyl transferase inhibitor SCH66336 and gemcitabine was evaluated. This therapy was used as second-line treatment in patients with advanced urothelial tract cancer and the influence of SCH66336 exposure on the pharmacokinetics of gemcitabine was also determined. Patients who had received one previous chemotherapy regime for advanced urothelial cancer were treated with a combination of SCH66336 (150 mg in the morning and 100 mg in the evening) and Gemcitabine (1000 mg/m2 on day 1, 8 and 15 per 28-day cycle). Dosages of gemcitabine and its metabolite dFdU were performed on day one of cycle 1 before exposure to SCH66336 and day one of cycle 2. A total of 152 cycles were administered in 33 patients (median 3, range: 1-15). No patients had severe hematological toxicity, defined as Grade 4 thrombocytopenia or febrile neutropenia. Nine partial responses and one complete response were achieved in 31 assessable patients and corresponded to an overall response rate of 32.3% [95% CI:17%-51%]. There was no influence of exposure to SCH66336 on the level of gemcitabine or dFdU in 11 assessable patients. In conclusion, a combination of SCH66336 and gemcitabine is feasible in terms of toxicity and active as second-line treatment in patients with advanced urothelial tract cancer. SCH66336 had no effect on the pharmacokinetics of gemcitabine. Randomised trials should be undertaken to clarify the role of SCH66336 in combination with gemcitabine in cancer treatment.

Topics: Adult; Aged; Aged, 80 and over; Alkyl and Aryl Transferases; Antineoplastic Combined Chemotherapy Protocols; Carcinoma, Transitional Cell; Deoxycytidine; Disease Progression; Farnesyltranstransferase; Feasibility Studies; Female; Gemcitabine; Humans; Male; Middle Aged; Piperidines; Pyridines; Salvage Therapy; Survival Analysis; Urologic Neoplasms

The authors evaluated the safety, tolerability, and efficacy of treatment using lonafarnib, a novel farnesyltransferase inhibitor (FTI), in combination with paclitaxel in patients with metastatic (Stage IIIB/V), taxane-refractory/resistant nonsmall cell lung carcinoma (NSCLC).. Patients with NSCLC who experienced disease progression while receiving previous taxane therapy or who had disease recurrence within 3 months after taxane therapy cessation were treated with continuous lonafarnib 100 mg orally twice per day beginning on Day 1 and paclitaxel 175 mg/m(2) intravenously over 3 hours on Day 8 of each 21-day cycle.. A total of 33 patients were enrolled, 29 of whom were evaluable for response. Partial responses (PR) and stable disease (SD) were observed in 3 (10%) and 11 patients (38%), respectively. Thus, 48% (14 of 29) experienced clinical benefit (PR or SD). The updated and final median overall survival time was 39 weeks and the median disease progression-free survival time was 16 weeks. The combination of lonafarnib and paclitaxel was well tolerated with minimal toxicity. Grade 3 toxicities included fatigue (9%), diarrhea (6%), and dyspnea (6%). Grade 3 neutropenia occurred in only 1 patient (3%). Grade 4 adverse events included respiratory insufficiency in 2 patients (6%) and acute respiratory failure in 1 patient (3%).. Lonafarnib plus paclitaxel demonstrated clinical activity in patients with taxane-refractory/resistant metastatic NSCLC. In addition, the combination of lonafarnib and paclitaxel was well tolerated with minimal toxicity. Evaluation of this combination therapy in additional clinical trials is warranted.

Topics: Adult; Aged; Alkyl and Aryl Transferases; Antineoplastic Agents, Phytogenic; Bridged-Ring Compounds; Carcinoma, Non-Small-Cell Lung; Drug Therapy, Combination; Enzyme Inhibitors; Farnesyltranstransferase; Female; Humans; Lung Neoplasms; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Staging; Paclitaxel; Piperidines; Pyridines; Remission Induction; Survival Rate; Taxoids; Treatment Outcome

To establish the maximum tolerated dose of lonafarnib, a novel farnesyltransferase inhibitor, in combination with paclitaxel in patients with solid tumors and to characterize the safety, tolerability, dose-limiting toxicity, and pharmacokinetics of this combination regimen.. In a Phase I trial, lonafarnib was administered p.o., twice daily (b.i.d.) on continuously scheduled doses of 100 mg, 125 mg, and 150 mg in combination with i.v. paclitaxel at doses of 135 mg/m(2) or 175 mg/m(2) administered over 3 h on day 8 of every 21-day cycle. Plasma paclitaxel and lonafarnib concentrations were collected at selected time points from each patient.. Twenty-four patients were enrolled; 21 patients were evaluable. The principal grade 3/4 toxicity was diarrhea (5 of 21 patients), which was most likely due to lonafarnib. dose-limiting toxicities included grade 3 hyperbilirubinemia at dose level 3 (100 mg b.i.d. lonafarnib and 175 mg/m(2) paclitaxel); grade 4 diarrhea and grade 3 peripheral neuropathy at dose level 3A (125 mg b.i.d. lonafarnib and 175 mg/m(2) paclitaxel); and grade 4 neutropenia with fever and grade 4 diarrhea at level 4 (150 mg b.i.d. lonafarnib and 175 mg/m(2) paclitaxel). The maximum tolerated dose established by the continual reassessment method was lonafarnib 100 mg b.i.d. and paclitaxel 175 mg/m(2). Paclitaxel appeared to have no effect on the pharmacokinetics of lonafarnib. The median duration of therapy was eight cycles, including seven cycles with paclitaxel. Six of 15 previously treated patients had a durable partial response, including 3 patients who had previous taxane therapy. Notably, two of five patients with taxane-resistant metastatic non-small cell lung cancer had partial responses.. When combined with paclitaxel, the recommended dose of lonafarnib for Phase II trials is 100 mg p.o. twice daily with 175 mg/m(2) of paclitaxel i.v. every 3 weeks. Additional studies of lonafarnib in combination regimens appear warranted, particularly in patients with non-small cell lung cancer.

Topics: Adult; Aged; Alkyl and Aryl Transferases; Anemia; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; Dose-Response Relationship, Drug; Farnesyltranstransferase; Fatigue; Female; Heart Arrest; Humans; Leukopenia; Male; Middle Aged; Neoplasms; Neutropenia; Paclitaxel; Piperidines; Pyridines; Treatment Outcome

ras genes encode Ras proteins that are important for signal transduction in cancer cells. Farnesyl protein transferase (FPTase) is an enzyme that is responsible for a critical post-translational modification of Ras.. We report the results of a phase II trial of SCH 66336, an FPTase inhibitor, in patients with metastatic colorectal cancer. This is the first reported experience of an FPTase inhibitor in this disease. All patients were considered refractory to first- and second-line therapy. A total of 21 evaluable patients were treated with a starting dose of 200 mg b.i.d. given continuously.. The major side-effects were fatigue (grade 1 in 42%, grade 2 in 42% and grade 3 in 14%), diarrhea (grade 1 in 23% and grade 3 in 42%) and nausea (grade 2 in 16%). Elevations in serum creatinine (grade 2 or 3) were observed in 19% of patients and appeared to be related to dehydration induced by diarrhea. Significant hematological toxicity was not observed (only grade 1 thrombocytopenia in 19% and grade 2 or 3 anemia in 28%). Pharmacological studies revealed adequate mean pre-dose plasma concentrations in this group of patients on day 15 of therapy. No objective responses were observed, although stable disease was seen in three patients for several months. Administration of SCH 66336 was accompanied by gastrointestinal toxicity.. Future development of this compound cannot be recommended as monotherapy in this disease.

Topics: Administration, Oral; Adult; Aged; Aged, 80 and over; Biopsy, Needle; Colorectal Neoplasms; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Resistance; Drug Resistance, Neoplasm; Enzyme Inhibitors; Female; Fluorouracil; Follow-Up Studies; Humans; Liver Neoplasms; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Piperidines; Pyridines; Survival Analysis; Treatment Outcome

A single-agent dose-escalating phase I study on the farnesyl transferase inhibitor SCH 66336 was performed to determine the safety profile and recommended dose for phase II studies. Plasma pharmacokinetics were determined as well as the SCH 66336-induced inhibition of farnesyl protein transferase in vivo. SCH 66336 was given orally once daily (OD) without interruption to patients with histologically-confirmed solid tumours. Routine antiemetics were not prescribed. 12 patients were enrolled into the study. Dose levels studied were 300 mg (6 patients) and 400 mg (6 patients) OD. Pharmacokinetic sampling was performed on days 1 and 15. Although at 400 mg OD only 1 patient had a grade 3 diarrhoea, 3 out of 6 patients interrupted treatment early due to a combination of various grade 1-3 toxicities (diarrhoea, uremiacreatinine, asthenia, vomiting, weight loss) indicating that this dose was not tolerable for a prolonged period of time. At 300 mg OD, the same pattern of toxicities was observed, but all were grade 1-2. Therefore, this dose can be recommended for phase II studies. Pharmacokinetic analysis showed that peak plasma concentrations as well as the AUCs were dose-related, with increased parameters at day 15 compared with day 1, indicating some accumulation upon multiple dosing. Plasma half-life ranged from 5 to 9 h and appeared to increase with increasing dose. Steady state plasma concentrations were attained by day 14. A large volume of distribution at steady state suggested extensive distribution outside the plasma compartment. There is evidence of inhibition of protein prenylation in some patients after OD oral administration of SCH 66336. SCH 66336 can be safely administered using a continuous oral OD dosing regimen. The recommended dose for phase II studies using this regimen is 300 mg OD.

Topics: Administration, Oral; Adult; Aged; Antineoplastic Agents; Drug Resistance, Neoplasm; Enzyme Inhibitors; Female; Follow-Up Studies; Humans; Male; Maximum Tolerated Dose; Middle Aged; Neoplasms; Piperidines; Pyridines

A single-agent dose-escalating phase I and pharmacokinetic study on the farnesyl transferase inhibitor SCH 66336 was performed to determine the safety profile, maximum-tolerated dose, and recommended dose for phase II studies. Plasma and urine pharmacokinetics were determined.. SCH 66336 was given orally bid without interruption to patients with histologically or cytologically confirmed solid tumors. Routine antiemetics were not prescribed.. Twenty-four patients were enrolled onto the study. Dose levels studied were 25, 50, 100, 200, 400, and 300 mg bid. Pharmacokinetic sampling was performed on days 1 and 15. At 400 mg bid, the dose-limiting toxicity (DLT) consisted of grade 4 vomiting, grade 4 neutropenia and thrombocytopenia, and the combination of grade 3 anorexia and diarrhea with reversible grade 3 plasma creatinine elevation. After dose reduction, at 300 mg bid, the DLTs consisted of grade 4 neutropenia, grade 3 neurocortical toxicity, and the combination of grade 3 fatigue with grade 2 nausea and diarrhea. The recommended dose for phase II studies is 200 mg bid, which was found feasible for prolonged periods of time. Pharmacokinetic analysis showed a greater than dose-proportional increase in drug exposure and peak plasma concentrations, with increased parameters at day 15 compared with day 1, indicating some accumulation on multiple dosing. Plasma half-life ranged from 4 to 11 hours and seemed to increase with increasing doses. Steady-state plasma concentrations were attained at days 7 through 14. A large volume of distribution at steady-state indicated extensive distribution outside the plasma compartment.. SCH 66336 can be administered safely using a continuous oral bid dosing regimen. The recommended dose for phase II studies using this regimen is 200 mg bid.

Topics: Administration, Oral; Adult; Aged; Alkyl and Aryl Transferases; Antineoplastic Agents; Enzyme Inhibitors; Farnesyltranstransferase; Female; Humans; Male; Middle Aged; Piperidines; Pyridines

Farnesyl protein transferase (FT), an enzyme that catalyzes the first step in the posttranslational modification of ras and a number of other polypeptides, has emerged as an important target for the development of anticancer agents. SCH66336 is one of the first FT inhibitors to undergo clinical testing. We report a Phase I trial to assess the maximum tolerated dose, toxicities, and biological effectiveness of SCH66336 in inhibiting FT in vivo. Twenty patients with solid tumors received 92 courses of escalating SCH66336 doses given orally twice a day (b.i.d.) for 7 days out of every 3 weeks. Gastrointestinal toxicity (nausea, vomiting, and diarrhea) and fatigue were dose-limiting at 400 mg of SCH66336 b.i.d. Moderate reversible renal insufficiency, secondary to dehydration from gastrointestinal toxicity, was also seen. Inhibition of prelamin A farnesylation in buccal mucosa cells of patients treated with SCH66336 was demonstrated, confirming that SCH66336 inhibits protein farnesylation in vivo. One partial response was observed in a patient with previously treated metastatic non-small cell lung cancer, who remained on study for 14 months. This study not only establishes the dose for future testing on this schedule (350 mg b.i.d.) but also provides the first evidence of successful inhibition of FT in the clinical setting and the first hint of clinical activity for this class of agents.

Topics: Adult; Aged; Aged, 80 and over; Alkyl and Aryl Transferases; Antineoplastic Agents; Dose-Response Relationship, Drug; Enzyme Inhibitors; Farnesyltranstransferase; Female; Humans; Lamin Type A; Lamins; Male; Middle Aged; Mouth Mucosa; Neoplasms; Nuclear Proteins; Piperidines; Protein Precursors; Pyridines

The U.S. Food and Drug Administration recently approved lonafarnib as the first treatment for Hutchinson-Gilford progeria syndrome (HGPS) and processing-deficient progeroid laminopathies. This approval was primarily based on a comparison of patients with HGPS treated with lonafarnib in 2 open-label trials with an untreated patient cohort. With up to 11 years of follow-up, it was found that the lonafarnib treated patients with HGPS had a survival benefit of 2.5 years compared with the untreated patients with HGPS. This large treatment effect on the objective endpoint of mortality using a well-matched comparator group mitigated potential sources of bias and together with other evidence, established compelling evidence of a drug effect with benefits that outweighed the risks. This approval is an example of U.S. Food and Drug Administration's regulatory flexibility for a rare disease while ensuring that standards for drug approval are met.

Topics: Humans; Lamin Type A; Piperidines; Progeria; Pyridines; United States

Clinical trials have demonstrated that lonafarnib, a farnesyltransferase inhibitor, extends the lifespan in patients afflicted by Hutchinson-Gilford progeria syndrome, a devastating condition that accelerates many characteristics of aging and results in premature death due to cardiovascular sequelae. The US Food and Drug Administration approved Zokinvy (lonafarnib) in November 2020 for treating these patients, yet a detailed examination of drug-associated effects on cardiovascular structure, properties, and function has remained wanting. In this paper, we report encouraging outcomes of daily post-weaning treatment with lonafarnib on the composition and biomechanical phenotype of elastic and muscular arteries as well as associated cardiac function in a well-accepted mouse model of progeria that exhibits severe perimorbid cardiovascular disease. Lonafarnib resulted in 100% survival of the treated progeria mice to the study end-point (time of 50% survival of untreated mice), with associated improvements in arterial structure and function working together to significantly reduce pulse wave velocity and improve left ventricular diastolic function. By contrast, neither treatment with the mTOR inhibitor rapamycin alone nor dual treatment with lonafarnib plus rapamycin improved outcomes over that achieved with lonafarnib monotherapy.

Topics: Animals; Lamin Type A; Mice; Piperidines; Progeria; Pulse Wave Analysis; Sirolimus

Topics: Hepatitis Delta Virus; Piperidines; Pyridines

Glioblastoma multiforme (GBM) is a highly malignant brain tumor with a poor prognosis. The GBM microenvironment is highly heterogeneous and is composed of many cell types including astrocytes and endothelial cells (ECs) along with tumor cells, which are responsible for heightened resistance to standard chemotherapeutic drugs such as Temozolomide (TMZ). Here, we investigated how drug treatments impact stemness marker expression of GBM cells in multicellular tumor spheroid (MCTS) models. Co- and tri-culture MCTS constructed using U87-MG GBM cells, astrocytes, and/or ECs were cultured for 7 days. At Day 7, 5 μM lonafarnib (LNF), 100 μM TMZ, or combination of 5 μM LNF + 100 μM TMZ was added and the MCTS were cultured for an additional 48 h. We assessed the spheroid sizes and expression of stemness markers- NESTIN, SOX2, CD133, NANOG, and OCT4- through qRT-PCR and immunostaining. Following 48 h treatment with LNF, TMZ or their combination (LNF + TMZ), the spheroid sizes decreased compared to the untreated control. We also observed that the expression of most of the stemness markers significantly increased in the LNF + TMZ treated condition as compared to the untreated condition. These results indicate that drug treatment can influence the stemness marker expression of GBM cells in MCTS models and these aspects must be considered while evaluating therapies. In future, by incorporating other relevant cell types, we can further our understanding of their crosstalk, eventually leading to the development of new therapeutic strategies.

Topics: Cell Line, Tumor; Dibenzocycloheptenes; Drug Resistance, Neoplasm; Endothelial Cells; Glioblastoma; Humans; Nestin; Piperidines; Pyridines; Spheroids, Cellular; Temozolomide; Tumor Microenvironment

Several new drugs have been approved to treat rare genetic disorders: setmelanotide for certain conditions causing obesity; lumasiran for primary hyperoxaluria type 1, a kidney disorder; and lonafarnib for two diseases that cause premature aging.

Topics: alpha-MSH; Anti-Obesity Agents; Humans; Piperidines; Progeria; Pyridines; Rare Diseases

Topics: Enzyme Inhibitors; Humans; Piperidines; Pyridines

Hutchinson-Gilford progeria syndrome (HGPS) is an ultra-rare multisystem premature aging disorder that leads to early death (mean age of 14.7 years) due to myocardial infarction or stroke. Most cases have a de novo point mutation at position G608G within exon 11 of the

Topics: Adolescent; Azetidines; Cells, Cultured; Child, Preschool; Enzyme Inhibitors; Farnesyltranstransferase; Female; Humans; Janus Kinase 1; Janus Kinase Inhibitors; Male; Piperidines; Progeria; Purines; Pyrazoles; Pyridines; STAT1 Transcription Factor; Sulfonamides

Topics: Adult; Chronic Disease; Female; Fibrosis; Global Burden of Disease; Hepatitis B; Hepatitis B Surface Antigens; Hepatitis B virus; Hepatitis D; Hepatitis Delta Virus; Humans; Incidence; Interferon-alpha; Lipopeptides; Liver Diseases; Male; Middle Aged; Piperidines; Prevalence; Pyridines; Risk Factors; Superinfection; Uzbekistan

Hutchinson-Gilford progeria syndrome (HGPS) is a uniformly fatal condition that is especially prevalent in skin, cardiovascular, and musculoskeletal systems. A wide gap exists between our knowledge of the disease and a promising treatment or cure. The aim of this study was to first characterize the musculoskeletal phenotype of the homozygous G608G BAC-transgenic progeria mouse model, and to determine the phenotype changes of HGPS mice after a five-arm preclinical trial of different treatment combinations with lonafarnib, pravastatin, and zoledronic acid. Microcomputed tomography and CT-based rigidity analyses were performed to assess cortical and trabecular bone structure, density, and rigidity. Bones were loaded to failure with three-point bending to assess strength. Contrast-enhanced µCT imaging of mouse femurs was performed to measure glycosaminoglycan content, thickness, and volume of the femoral head articular cartilage. Advanced glycation end products were assessed with a fluorometric assay. The changes demonstrated in the cortical bone structure, rigidity, stiffness, and modulus of the HGPS G608G mouse model may increase the risk for bending and deformation, which could result in the skeletal dysplasia characteristic of HGPS. Cartilage abnormalities seen in this HGPS model resemble changes observed in the age-matched WT controls, including early loss of glycosaminoglycans, and decreased cartilage thickness and volume. Such changes might mimic prevalent degenerative joint diseases in the elderly. Lonafarnib monotherapy did not improve bone or cartilage parameters, but treatment combinations with pravastatin and zoledronic acid significantly improved bone structure and mechanical properties and cartilage structural parameters, which ameliorate the musculoskeletal phenotype of the disease.

Topics: Aging; Animals; Bone and Bones; Bone Density Conservation Agents; Cartilage; Disease Models, Animal; Femur; Glycosaminoglycans; Joints; Lamin Type A; Mice; Mice, Transgenic; Mutation; Osteoarthritis; Phenotype; Piperidines; Pravastatin; Progeria; Protein Processing, Post-Translational; Pyridines; X-Ray Microtomography; Zoledronic Acid

Multi-targeted tyrosine kinase inhibitors (TKIs) are the standard of care for patients with advanced clear cell renal cell carcinoma (ccRCC). However, a significant number of ccRCC patients are primarily refractory to targeted therapeutics, showing neither disease stabilisation nor clinical benefits.. We used CRISPR/Cas9-based high-throughput loss of function (LOF) screening to identify cellular factors involved in the resistance to sunitinib. Next, we validated druggable molecular factors that are synthetically lethal with sunitinib treatment using cell and animal models of ccRCC.. Our screening identified farnesyltransferase among the top hits contributing to sunitinib resistance in ccRCC. Combined treatment with farnesyltransferase inhibitor lonafarnib potently augmented the anti-tumour efficacy of sunitinib both in vitro and in vivo.. CRISPR/Cas9 LOF screening presents a promising approach to identify and target cellular factors involved in the resistance to anti-cancer therapeutics.

Topics: Animals; Antineoplastic Agents; Apoptosis; Carcinoma, Renal Cell; Cell Line, Tumor; CRISPR-Cas Systems; DNA Fragmentation; Drug Interactions; Drug Resistance, Neoplasm; Drug Therapy, Combination; Enzyme Inhibitors; Farnesyltranstransferase; High-Throughput Screening Assays; Humans; Kidney Neoplasms; Lysosomes; Male; Mechanistic Target of Rapamycin Complex 1; Mice; Molecular Targeted Therapy; Neoplasm Transplantation; Piperidines; Progression-Free Survival; Protein Kinase Inhibitors; Pyridines; Random Allocation; RNA, Small Interfering; Sunitinib

Therapeutic approaches for cutaneous melanoma are flourishing, but despite promising results, there is an increasing number of reported primary or secondary resistance to the growing sets of drugs approved for therapy in the clinics. Combinatorial approaches may overcome resistance, as they may tackle specific weaknesses of melanoma cells, not sufficient on their own, but effective in combination with other therapies. The transgenic zebrafish line kita:ras develops melanoma with high frequency. At 3 dpf, transgenic kita:ras larvae show a hyperpigmentation phenotype as earliest evidence of abnormal melanocyte growth. Using this model, we performed a chemical screen based on automated detection of a reduction of melanocyte number caused by any of 1280 FDA or EMA approved drugs of the library. The analysis showed that 55 molecules were able to reduce by 60% or more the number of melanocytes per embryo. We further tested two compounds for each of the 5 classes, and a farnesyltransferase inhibitor (Lonafarnib), that inhibits an essential post-translational modification of HRAS and suppresses the hyperpigmentation phenotype. Combinations of Clotrimazole and Lonafarnib showed the most promising results in zebrafish embryos, allowing a dose reduction of both drugs. We performed validation of these observations in the metastatic human melanoma cell line A375M, and in normal human epithelial melanocytes (NHEM) in order to investigate the mechanism of action of Clotrimazole in blocking the proliferation of transformed melanocytes. Viability assay and analysis of energy metabolism in Clotrimazole treated cells show that this drug specifically affects melanoma cells in vitro and transformed melanocytes in vivo, having no effects on NHEM or wild type larvae. Similar effects were observed with another hit of the same class, Miconazole. Furthermore, we show that the effects of Clotrimazole are mediated by the inhibition of hexokinase activity, which is lethal to the abnormal metabolic profile of melanoma cells in vitro and in vivo. Thus, our study shows that the zebrafish can provide a phenotype-rich assay for fully automated screening approaches to identify drugs for synthetic lethal treatment in melanoma and suggest further testing of Clotrimazole in combinatorial treatments.

Topics: Animals; Animals, Genetically Modified; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Cell Proliferation; Cell Survival; Clotrimazole; Disease Models, Animal; Drug Screening Assays, Antitumor; Farnesyltranstransferase; Humans; Melanocytes; Melanoma; Melanoma, Cutaneous Malignant; Miconazole; Piperidines; Pyridines; Skin Neoplasms; Zebrafish

Combination treatment is a promising strategy to improve prognosis of hepatocellular carcinoma (HCC). Sorafenib is a traditional first-line agent approved for the treatment of advanced HCC, though with limited efficacy. Previously, we reported that lonafarnib, an orally bioavailable non-peptide inhibitor targeting farnesyltransferase, synergizes with sorafenib against the growth of HCC cells. In the present study, we aim to clarify the underlying mechanism of this combination strategy. Initially, using in vitro HCC cell model, we confirmed that synergistic treatment of lonafarnib and sorafenib suppressed cell viability and colony formation, and induced cell death. We then found conversion of LC3-I to LC3-II via combination the treatment and observed formation of autophagosomes by electron microscopy. Knockdown of ATG3 inhibited the autophagic flux induced by the combination treatment. Furthermore, we demonstrated that drug-eliciting autophagy selectively promoted the degradation of cyclin D1 in a lysosome-dependent manner and subsequently inhibited DNA synthesis through downregulating the phosphorylation of Rb protein. In conclusion, our results provide a deeper insight into the mechanism for the combination treatment of lonafarnib and sorafenib in HCC therapy.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Autophagy; Autophagy-Related Proteins; Carcinoma, Hepatocellular; Cell Proliferation; Cyclin D1; Enzyme Inhibitors; Farnesyltranstransferase; Female; Gene Knockdown Techniques; Hep G2 Cells; Humans; Liver Neoplasms; Mice; Mice, Nude; Models, Biological; Piperidines; Protein Kinase Inhibitors; Proteolysis; Pyridines; Sorafenib; Ubiquitin-Conjugating Enzymes; Xenograft Model Antitumor Assays

Topics: Animals; Blastocyst; Centromere; Chromosomal Proteins, Non-Histone; Embryo, Mammalian; Embryonic Development; Farnesyltranstransferase; Female; Gene Knockdown Techniques; Metaphase; Mice; Mice, Inbred ICR; Microfilament Proteins; Morpholinos; Morula; Oocytes; Parthenogenesis; Piperidines; Pregnancy; Prenylation; Pyridines; Zygote

Tau inclusions are a shared feature of many neurodegenerative diseases, among them frontotemporal dementia caused by tau mutations. Treatment approaches for these conditions include targeting posttranslational modifications of tau proteins, maintaining a steady-state amount of tau, and preventing its tendency to aggregate. We discovered a new regulatory pathway for tau degradation that operates through the farnesylated protein, Rhes, a GTPase in the Ras family. Here, we show that treatment with the farnesyltransferase inhibitor lonafarnib reduced Rhes and decreased brain atrophy, tau inclusions, tau sumoylation, and tau ubiquitination in the rTg4510 mouse model of tauopathy. In addition, lonafarnib treatment attenuated behavioral abnormalities in rTg4510 mice and reduced microgliosis in mouse brain. Direct reduction of Rhes in the rTg4510 mouse by siRNA reproduced the results observed with lonafarnib treatment. The mechanism of lonafarnib action mediated by Rhes to reduce tau pathology was shown to operate through activation of lysosomes. We finally showed in mouse brain and in human induced pluripotent stem cell-derived neurons a normal developmental increase in Rhes that was initially suppressed by tau mutations. The known safety of lonafarnib revealed in human clinical trials for cancer suggests that this drug could be repurposed for treating tauopathies.

Topics: Animals; Brain; Disease Models, Animal; Enzyme Inhibitors; Farnesyltranstransferase; Female; GTP-Binding Proteins; Humans; Induced Pluripotent Stem Cells; Lysosomes; Male; Mice; Mice, Transgenic; Mutation; Neurons; Piperidines; Proteolysis; Pyridines; RNA, Small Interfering; tau Proteins; Tauopathies; Translational Research, Biomedical

Children with Hutchinson-Gilford progeria syndrome (HGPS), a rare premature aging disease, exhibit extraskeletal calcifications detected by radiographic analysis and on physical examination. The aim of this study was to describe the natural history and pathophysiology of these abnormal calcifications in HGPS, and to determine whether medications and/or supplements tested in clinical trials alter their development.. Children from two successive clinical trials administering 1) lonafarnib (n = 26) and 2) lonafarnib + pravastatin + zoledronic acid (n = 37) were studied at baseline (pre-therapy), one year on therapy, and at end-of-therapy (3.3-4.3 years after the baseline visit). Calcium supplementation (oral calcium carbonate) was administered during the first year of the second trial and was subsequently discontinued. Information on calcifications was obtained from physical examinations, radiographs, and serum and urinary biochemical measures. The mineral content of two skin-derived calcifications was determined by x-ray diffraction.. Extraskeletal calcifications were detected radiographically in 12/39 (31%) patients at baseline. The odds of exhibiting calcifications increased with age (p = 0.045). The odds were unaffected by receipt of lonafarnib, pravastatin, and zoledronate therapies. However, administration of calcium carbonate supplementation, in conjunction with all three therapeutic agents, significantly increased the odds of developing calcifications (p = 0.009), with the odds plateauing after the supplement's discontinuation. Composition analysis of calcinosis cutis showed hydroxyapatite similar to bone. Although serum calcium, phosphorus, and parathyroid hormone (PTH) were within normal limits at baseline and on-therapy, PTH increased significantly after lonafarnib initiation (p < 0.001). Both the urinary calcium/creatinine ratio and tubular reabsorption of phosphate (TRP) were elevated at baseline in 22/39 (56%) and 31/37 (84%) evaluable patients, respectively, with no significant changes while on-therapy. The mean calcium × phosphorus product (Ca × Pi) was within normal limits, but plasma magnesium decreased over both clinical trials. Fibroblast growth factor 23 (FGF23) was lower compared to age-matched controls (p = 0.03).. Extraskeletal calcifications increased with age in children with HGPS and were composed of hydroxyapatite. The urinary calcium/creatinine ratio and TRP were elevated for age while FGF23 was decreased. Magnesium decreased and PTH increased after lonafarnib therapy which may alter the ability to mobilize calcium. These findings demonstrate that children with HGPS with normal renal function and an unremarkable Ca × Pi develop extraskeletal calcifications by an unidentified mechanism that may involve decreased plasma magnesium and FGF23. Calcium carbonate accelerated their development and is, therefore, not recommended for routine supplementation in these children.

Topics: Calcinosis; Calcium; Child; Child, Preschool; Creatinine; Female; Fibroblast Growth Factor-23; Humans; In Vitro Techniques; Lamin Type A; Male; Parathyroid Hormone; Piperidines; Pravastatin; Progeria; Pyridines; Zoledronic Acid

Hutchinson-Gilford progeria syndrome (HGPS) is characterized by accelerated senescence due to a de novo mutation in the LMNA gene. The mutation produces an abnormal lamin A protein called progerin that lacks the splice site necessary to remove a farnesylated domain. Subsequently, progerin accumulates in the nuclear envelope, disrupting nuclear architecture, chromatin organization, and gene expression. These alterations are often associated with rapid telomere erosion and cellular aging. Here, we further characterize the cellular and molecular abnormalities in HGPS cells and report a significant reversal of some of these abnormalities by introduction of in vitro transcribed and purified human telomerase (hTERT) mRNA. There is intra-individual heterogeneity of expression of telomere-associated proteins DNA PKcs/Ku70/Ku80, with low-expressing cells having shorter telomeres. In addition, the loss of the heterochromatin marker H3K9me3 in progeria is associated with accelerated telomere erosion. In HGPS cell lines characterized by short telomeres, transient transfections with hTERT mRNA increase telomere length, increase expression of telomere-associated proteins, increase proliferative capacity and cellular lifespan, and reverse manifestations of cellular senescence as assessed by β-galactosidase expression and secretion of inflammatory cytokines. Unexpectedly, mRNA hTERT also improves nuclear morphology. In combination with the farnesyltransferase inhibitor (FTI) lonafarnib, hTERT mRNA promotes HGPS cell proliferation. Our findings demonstrate transient expression of human telomerase in combination with FTIs could represent an improved therapeutic approach for HGPS.

Topics: Adolescent; Adult; Aged; Cell Line; Cellular Senescence; Child; Child, Preschool; Enzyme Inhibitors; Farnesyltranstransferase; Female; Fibroblasts; Humans; Infant; Infant, Newborn; Lamin Type A; Male; Piperidines; Progeria; Pyridines; RNA, Messenger; Telomerase; Telomere; Telomere Homeostasis; Transfection

Topics: Amebicides; Anisomycin; Asymptomatic Diseases; Drug Discovery; Dysentery, Amebic; Entamoeba histolytica; Flavonoids; Gene Expression Regulation; Humans; Life Cycle Stages; Metabolic Networks and Pathways; Metronidazole; Piperidines; Prodigiosin; Protozoan Proteins; Pyridines; Severity of Illness Index

BackgroundHutchinson-Gilford progeria syndrome (HGPS) is an ultra-rare, fatal, segmental premature aging syndrome caused by the aberrant lamin A protein, progerin. The protein farnesyltransferase inhibitor, lonafarnib, ameliorates some aspects of cardiovascular and bone disease.MethodsWe performed a prospective longitudinal survey of plasma proteins in 24 children with HGPS (an estimated 10% of the world's population at the time) at baseline and on lonafarnib therapy, compared with age- and gender-matched controls using a multi-analyte, microsphere-based immunofluorescent assay.ResultsThe mean levels for 23/66 (34.8%) proteins were significantly lower and 7/66 (10.6%) were significantly higher in HGPS samples compared with those in controls (P≤0.05). Six proteins whose concentrations were initially lower normalized with lonafarnib therapy: interleukins 1α, 7, and 13, beta-2 microglobulin, C-reactive protein, and myoglobin. Alpha-2 macroglobulin, a protease inhibitor associated with stroke, was elevated at baseline and subsequently normalized with lonafarnib therapy.ConclusionThis is the first study to employ a multi-analyte array platform in HGPS. Novel potential biomarkers identified in this study should be further validated by correlations with clinical disease status, especially proteins associated with cardiovascular disease and those that normalized with lonafarnib therapy.

Topics: Adolescent; beta 2-Microglobulin; Biomarkers; Blood Proteins; C-Reactive Protein; Case-Control Studies; Child; Child, Preschool; Enzyme Inhibitors; Female; Humans; Interleukin-13; Interleukin-1alpha; Interleukin-7; Lamin Type A; Longitudinal Studies; Male; Mutation; Myoglobin; Piperidines; Progeria; Prospective Studies; Pyridines

Topics: Hepatitis Delta Virus; Piperidines; Prenylation; Pyridines

Topics: Cell Nucleus; Child, Preschool; Enzyme Inhibitors; Farnesyltranstransferase; Female; Humans; Lamin Type A; Mutation; Piperidines; Progeria; Pyridines

Farnesylation, which is catalyzed by farnesyltransferase, promotes membrane association of the modified protein and protein-protein interactions, and plays an important role in a number of physiological processes of pathogenic fungi, including stress response, environmental adaption and virulence. Lonafarnib is an orally bioavailable nonpeptide tricyclic farnesyltransferase inhibitor with excellent pharmacokinetic and safety profile. In the present study, we investigated the in vitro activities of lonafarnib alone or combined with azoles, including itraconazole, voriconazole, and posaconazole, against 22 strains of Aspergillus spp. and 18 strains of Exophiala dermatitidis via broth microdilution checkerboard technique. Lonafarnib alone was inactive against all isolates tested. However, synergistic effects between lonafarnib and itraconazole were observed in 86% Aspergillus strains and 94% E. dermatitidis strains. In addition, lonafarnib/posaconazole combination also exhibited synergism against 59% of Aspergillus strains and 100% E. dermatitidis strains. However, synergistic effects of lonafarnib/voriconazole were only observed in 32% Aspergillus strains and 28% E. dermatitidis strains. The effective working ranges of lonafarnib were 2-4 μg/ml and 1-4 μg/ml against Aspergillus isolates and E. dermatitidis isolates, respectively. No antagonism was observed in all combinations. This study demonstrated that lonafarnib could enhance the in vitro antifungal activity of itraconazole, posaconazole and voriconazole against Aspergillus spp. and E. dermatitidis, suggesting that azoles, especially itraconazole and posaconazole, combined with farnesyltransferase inhibitor might provide a potential strategy to the management of Aspergillus and Exophiala infections. However, further studies are warranted to elucidate the underlying mechanism and to investigate the potential of reliable and safe application in clinical practice.

Topics: Antifungal Agents; Aspergillus; Azoles; Drug Synergism; Exophiala; Humans; Microbial Sensitivity Tests; Piperidines; Pyridines

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare fatal premature aging disease. There is no approved treatment.. To evaluate the association of monotherapy using the protein farnesyltransferase inhibitor lonafarnib with mortality rate in children with HGPS.. Cohort study comparing contemporaneous (birth date ≥1991) untreated patients with HGPS matched with treated patients by age, sex, and continent of residency using conditional Cox proportional hazards regression. Treatment cohorts included patients from 2 single-group, single-site clinical trials (ProLon1 [n = 27; completed] and ProLon2 [n = 36; ongoing]). Untreated patients originated from a separate natural history study (n = 103). The cutoff date for patient follow-up was January 1, 2018.. Treated patients received oral lonafarnib (150 mg/m2) twice daily. Untreated patients received no clinical trial medications.. The primary outcome was mortality. The primary analysis compared treated patients from the first lonafarnib trial with matched untreated patients. A secondary analysis compared the combined cohorts from both lonafarnib trials with matched untreated patients.. Among untreated and treated patients (n = 258) from 6 continents, 123 (47.7%) were female; 141 (54.7%) had a known genotype, of which 125 (88.7%) were classic (c.1824C>T in LMNA). When identified (n = 73), the primary cause of death was heart failure (79.4%). The median treatment duration was 2.2 years. Median age at start of follow-up was 8.4 (interquartile range [IQR], 4.8-9.5) years in the first trial cohort and 6.5 (IQR, 3.7-9.0) years in the combined cohort. There was 1 death (3.7%) among 27 patients in the first trial group and there were 9 deaths (33.3%) among 27 patients in the matched untreated group. Treatment was associated with a lower mortality rate (hazard ratio, 0.12; 95% CI, 0.01-0.93; P = .04). In the combined cohort, there were 4 deaths (6.3%) among 63 patients in the treated group and 17 deaths (27.0%) among 63 patients in the matched untreated group (hazard ratio, 0.23; 95% CI, 0.06-0.90; P = .04).. Among patients with HGPS, lonafarnib monotherapy, compared with no treatment, was associated with a lower mortality rate after 2.2 years of follow-up. Study interpretation is limited by its observational design.

Topics: Adolescent; Adult; Cause of Death; Child; Cohort Studies; Enzyme Inhibitors; Female; Humans; Kaplan-Meier Estimate; Lamin Type A; Male; Phosphotransferases (Phosphate Group Acceptor); Piperidines; Progeria; Protein Processing, Post-Translational; Pyridines; Young Adult

Chronic delta hepatitis, caused by hepatitis delta virus (HDV), is the most severe form of viral hepatitis, affecting at least 20 million hepatitis B virus (HBV)-infected patients worldwide. HDV/HBV co- or superinfections are major drivers for hepatocarcinogenesis. Antiviral treatments exist only for HBV and can only suppress but not cure infection. Development of more effective therapies has been impeded by the scarcity of suitable small-animal models. We created a transgenic (tg) mouse model for HDV expressing the functional receptor for HBV and HDV, the human sodium taurocholate cotransporting peptide NTCP. Both HBV and HDV entered hepatocytes in these mice in a glycoprotein-dependent manner, but one or more postentry blocks prevented HBV replication. In contrast, HDV persistently infected hNTCP tg mice coexpressing the HBV envelope, consistent with HDV dependency on the HBV surface antigen (HBsAg) for packaging and spread. In immunocompromised mice lacking functional B, T, and natural killer cells, viremia lasted at least 80 days but resolved within 14 days in immunocompetent animals, demonstrating that lymphocytes are critical for controlling HDV infection. Although acute HDV infection did not cause overt liver damage in this model, cell-intrinsic and cellular innate immune responses were induced. We further demonstrated that single and dual treatment with myrcludex B and lonafarnib efficiently suppressed viremia but failed to cure HDV infection at the doses tested. This small-animal model with inheritable susceptibility to HDV opens opportunities for studying viral pathogenesis and immune responses and for testing novel HDV therapeutics.

Topics: Adaptive Immunity; Animals; Disease Models, Animal; Drug Therapy, Combination; Genome, Viral; Glycoproteins; Hepatitis B virus; Hepatitis D; Hepatitis Delta Virus; Hepatocytes; Humans; Immunity, Innate; Immunocompetence; Lipopeptides; Mice, Inbred C57BL; Mice, Transgenic; Organic Anion Transporters, Sodium-Dependent; Piperidines; Pyridines; Symporters; Transgenes; Viremia

There are 8 different human syndromes caused by mutations in the cholesterol synthesis pathway. A subset of these disorders such as Smith-Lemli-Opitz disorder, are associated with facial dysmorphia. However, the molecular and cellular mechanisms underlying such facial deficits are not fully understood, primarily because of the diverse functions associated with the cholesterol synthesis pathway. Recent evidence has demonstrated that mutation of the zebrafish ortholog of HMGCR results in orofacial clefts. Here we sought to expand upon these data, by deciphering the cholesterol dependent functions of the cholesterol synthesis pathway from the cholesterol independent functions. Moreover, we utilized loss of function analysis and pharmacological inhibition to determine the extent of sonic hedgehog (Shh) signaling in animals with aberrant cholesterol and/or isoprenoid synthesis. Our analysis confirmed that mutation of hmgcs1, which encodes the first enzyme in the cholesterol synthesis pathway, results in craniofacial abnormalities via defects in cranial neural crest cell differentiation. Furthermore targeted pharmacological inhibition of the cholesterol synthesis pathway revealed a novel function for isoprenoid synthesis during vertebrate craniofacial development. Mutation of hmgcs1 had no effect on Shh signaling at 2 and 3 days post fertilization (dpf), but did result in a decrease in the expression of gli1, a known Shh target gene, at 4 dpf, after morphological deficits in craniofacial development and chondrocyte differentiation were observed in hmgcs1 mutants. These data raise the possibility that deficiencies in cholesterol modulate chondrocyte differentiation by a combination of Shh independent and Shh dependent mechanisms. Moreover, our results describe a novel function for isoprenoids in facial development and collectively suggest that cholesterol regulates craniofacial development through versatile mechanisms.

Topics: Animals; Anticholesteremic Agents; Atorvastatin; Benzophenones; Body Patterning; Cell Differentiation; Cholesterol; Chondrocytes; Craniofacial Abnormalities; Embryo, Nonmammalian; Enzyme Inhibitors; Gene Expression Regulation, Developmental; Hedgehog Proteins; Humans; Hydroxymethylglutaryl CoA Reductases; Hydroxymethylglutaryl-CoA Synthase; Neural Crest; Piperidines; Pyridines; Signal Transduction; Terpenes; Zebrafish; Zebrafish Proteins; Zinc Finger Protein GLI1

Progeria is a rare genetic disorder characterized by premature aging that eventually leads to death and is noticed globally. Despite alarming conditions, this disease lacks effective medications; however, the farnesyltransferase inhibitors (FTIs) are a hope in the dark. Therefore, the objective of the present article is to identify new compounds from the databases employing pharmacophore based virtual screening. Utilizing nine training set compounds along with lonafarnib, a common feature pharmacophore was constructed consisting of four features. The validated Hypo1 was subsequently allowed to screen Maybridge, Chembridge, and Asinex databases to retrieve the novel lead candidates, which were then subjected to Lipinski's rule of 5 and ADMET for drug-like assessment. The obtained 3,372 compounds were forwarded to docking simulations and were manually examined for the key interactions with the crucial residues. Two compounds that have demonstrated a higher dock score than the reference compounds and showed interactions with the crucial residues were subjected to MD simulations and binding free energy calculations to assess the stability of docked conformation and to investigate the binding interactions in detail. Furthermore, this study suggests that the Hits may be more effective against progeria and further the DFT studies were executed to understand their orbital energies.

Topics: Drug Design; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Molecular Docking Simulation; Molecular Dynamics Simulation; Piperidines; Progeria; Pyridines

The Hutchinson-Gilford syndrome or progeria is a rare autosomal dominant syndrome characterized by premature aging and involvement of internal systems, such as the circulatory and locomotor. The diagnosis is essentially clinical and the manifestations become more evident from the first year of life. Long term outcome data from Progeria Research Foundation clinical trials have demonstrated an increase in survival in recent years. Even though new trials are ongoing, the recognition of this syndrome is essential to prevent cardiovascular and cerebrovascular complications. A patient, initially asymptomatic, who developed characteristic signs of the syndrome at the age of 6 months is reported. She was referred for evaluation only when she was two years and eleven months old. The diagnosis of Hutchinson-Gilford syndrome was suspected owing to clinical characteristics. The diagnosis was confirmed by genetic testing. A mutation c.1824C> T in exon 11 of the LMNA gene was detected. She was registered in the Progeria Research Foundation and was invited to participate in the weighing and supplementation program. She was included in the lonafarnib protocol study. This medication is a farnesyl transferase inhibitor that prevents the production of progerina and slows cardiovascular and neurological complications of the syndrome. This case highlights the importance of diagnosing progeria patients because they may be referred to the Progeria Research Foundation, which offers genetic screening and inclusion in clinical and therapeutic follow-up protocols without any costs. Progeria trials and research may also contribute to new drug developments related to prevention of aging and atherosclerosis in the near future.

Topics: Aging; Body Height; Body Weight; Child; Child, Preschool; Enzyme Inhibitors; Female; Humans; Infant; Lamin Type A; Piperidines; Progeria; Pyridines

Atherosclerosis is a common cardiovascular disease that involves the build-up of plaque on the inner walls of the arteries. Intraplaque neovacularization has been shown to be essential in the pathogenesis of atherosclerosis. Previous studies showed that small-molecule compounds targeting farnesyl transferase have the ability to prevent atherosclerosis in apolipoprotein E-deficient mice, but the underlying mechanism remains to be elucidated. In this study, we found that lonafarnib, a specific inhibitor of farnesyl transferase, elicits inhibitory effect on vascular endothelial capillary assembly in vitro in a dose-dependent manner. In addition, we showed that lonafarnib treatment led to a dose-dependent decrease in scratch wound closure in vitro, whereas it had little effect on endothelial cell proliferation. These data indicate that lonafarnib inhibits neovascularization via directly targeting endothelial cells and disturbing their motility. Moreover, we demonstrated that pharmacological inhibition of farnesyl transferase by lonafarnib significantly impaired centrosome reorientation toward the leading edge of endothelial cells. Mechanistically, we found that the catalytic β subunit of farnesyl transferase associated with a cytoskeletal protein important for the establishment and maintenance of cell polarity. Additionally, we showed that lonafarnib remarkably inhibited the expression of the cytoskeletal protein and interrupted its interaction with farnesyl transferase. Our findings thus offer novel mechanistic insight into the protective effect of farnesyl transferase inhibitors on atherosclerosis and provide encouraging evidence for the potential use of this group of agents in inhibiting plaque neovascularization.

Topics: Alkyl and Aryl Transferases; Animals; Apolipoproteins E; Atherosclerosis; Cell Polarity; Cell Proliferation; Cytoskeletal Proteins; Endothelial Cells; Gene Expression Regulation; Humans; Mice; Neovascularization, Pathologic; Piperidines; Pyridines

RAS-driven malignancies remain a major therapeutic challenge. The two-stage 7,12-dimethylbenz(a)anthracene (DMBA)/12-o-tetradecanoylphorbol-13-acetate (TPA) model of mouse skin carcinogenesis has been used to study mechanisms of epithelial tumor development by oncogenic Hras. We used mice with an Hras(G12V) knock-in allele to elucidate the early events after Hras activation, and to evaluate the therapeutic effectiveness of farnesyltransferase inhibition (FTI). Treatment of Caggs-Cre/FR-Hras(G12V) mice with TPA alone was sufficient to trigger papilloma development with a shorter latency and an ∼10-fold greater tumor burden than DMBA/TPA-treated WT-controls. Hras(G12V) allele copy number was increased in all papillomas induced by TPA. DMBA/TPA treatment of Hras(G12V) knock-in mice induced an even greater incidence of papillomas, which either harbored Hras(G12V) amplification or developed an Hras(Q61L) mutation in the second allele. Laser-capture microdissection of normal skin, hyperplastic skin and papillomas showed that amplification occurred only at the papilloma stage. HRAS-mutant allelic imbalance was also observed in human cancer cell lines, consistent with a requirement for augmented oncogenic HRAS signaling for tumor development. The FTI SCH66336 blocks HRAS farnesylation and delocalizes it from the plasma membrane. NRAS and KRAS are not affected as they are alternatively prenylated. When tested in lines harboring HRAS, NRAS or KRAS mutations, SCH66336 delocalized, inhibited signaling and preferentially inhibited growth only of HRAS-mutant lines. Treatment with SCH66336 also induced near-complete regression of papillomas of TPA-treated Hras(G12V) knock-in mice. These data suggest that farnesyl transferase inhibitors should be reevaluated as targeted agents for human HRAS-driven cancers, such as those of bladder, thyroid and other epithelial lineages.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Cell Line, Tumor; Enzyme Inhibitors; Farnesyltranstransferase; Gene Dosage; Gene Knock-In Techniques; Genes, ras; Humans; Mice, Mutant Strains; Mutation; Papilloma; Piperidines; Pyridines; Skin Neoplasms; Tetradecanoylphorbol Acetate

Farnesyltransferase (FTase) and geranylgeranyltransferase type-I (GGTase-I) are two members of protein prenyltransferases, which play critical roles in lipid post-translational modifications. Potent inhibitors of FTase and GGTase-I have been confirmed to show favorable influence on the therapies of various diseases, such as cancers, malaria and Toxoplasmosis. However, designing highly specific inhibitors toward FTase or GGTase-I without influencing their binding affinity remains a big challenge. In this work, molecular docking, molecular dynamics (MD) simulations and MM/GBSA free energy calculations were employed to study the bindings of two highly selective inhibitors (lonafarnib and GGTI-2133) towards FTase or GGTase-I. The specificities of the studied inhibitors derived from the predicted binding free energies are consistent with the experimental data. The analysis of the energetic components illustrates that both the non-polar and polar interactions play critical roles in determining the specificity between FTase and GGTase-I. Moreover, the protein-inhibitor interaction spectra for the studied inhibitors were determined through the decomposition of the binding free energies, and the important residues for binding and specificity were highlighted. Our study provides useful information for the rational design of selective FTase or GGTase-I inhibitors.

Topics: Alkyl and Aryl Transferases; Animals; Enzyme Inhibitors; Farnesyltranstransferase; Imidazoles; Leucine; Molecular Docking Simulation; Molecular Dynamics Simulation; Naphthalenes; Piperidines; Protein Binding; Pyridines; Rats; Thermodynamics

Hutchinson-Gilford progeria syndrome is an ultrarare segmental premature aging disease resulting in early death from heart attack or stroke. There is no approved treatment, but starting in 2007, several recent single-arm clinical trials administered inhibitors of protein farnesylation aimed at reducing toxicity of the disease-producing protein progerin. No study assessed whether treatments influence patient survival. The key elements necessary for this analysis are a robust natural history of survival and comparison with a sufficiently large patient population that has been treated for a sufficient time period with disease-targeting medications.. We generated Kaplan-Meier survival analyses for the largest untreated Hutchinson-Gilford progeria syndrome cohort to date. Mean survival was 14.6 years. Comparing survival for treated versus age- and sex-matched untreated cohorts, hazard ratio was 0.13 (95% confidence interval, 0.04-0.37; P<0.001) with median follow-up of 5.3 years from time of treatment initiation. There were 21 of 43 deaths in untreated versus 5 of 43 deaths among treated subjects. Treatment increased mean survival by 1.6 years.. This study provides a robust untreated disease survival profile that can be used for comparisons now and in the future to assess changes in survival with treatments for Hutchinson-Gilford progeria syndrome. The current comparisons estimating increased survival with protein farnesylation inhibitors provide the first evidence of treatments influencing survival for this fatal disease.. http://www.clinicaltrials.gov. Unique Indentifiers: NCT00425607, NCT00879034, and NCT00916747.

Topics: Adolescent; Adult; Alkyl and Aryl Transferases; Atherosclerosis; Cause of Death; Child; Child, Preschool; Clinical Trials as Topic; Cohort Studies; Dimethylallyltranstransferase; Diphosphonates; Drug Therapy, Combination; Female; Genes, Dominant; Genotype; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Imidazoles; Kaplan-Meier Estimate; Lamin Type A; Male; Multicenter Studies as Topic; Nuclear Proteins; Piperidines; Pravastatin; Progeria; Proportional Hazards Models; Protein Precursors; Protein Prenylation; Pyridines; Treatment Outcome; Young Adult; Zoledronic Acid

Topics: Diphosphonates; Female; Humans; Imidazoles; Lamin Type A; Male; Nuclear Proteins; Piperidines; Pravastatin; Progeria; Protein Precursors; Protein Prenylation; Pyridines; Zoledronic Acid

Topics: Aging; Child; Clinical Trials as Topic; Diphosphonates; Drug Discovery; Humans; Imidazoles; Lamin Type A; Mutation; Piperidines; Pravastatin; Progeria; Pyridines; Time Factors; Zoledronic Acid

Topics: Female; Humans; Male; Nervous System Diseases; Piperidines; Progeria; Pyridines

Metastasis is a critical event in the progression of head and neck squamous cell carcinoma (HNSCC) and closely correlates with clinical outcome. We previously showed that the farnesyl transferase inhibitor SCH66336 has antitumor activities in HNSCC by inducing the secretion of insulin-like growth factor binding protein 3 (IGFBP-3), which in turn inhibits tumor growth and angiogenesis. In our study, we found that SCH66336 at a sublethal dose for HNSCC inhibited the migration and invasion of HNSCC cells. The inhibitory effect of SCH66336 was associated with the blockade of the IGF-1 receptor (IGF-1R) pathway via suppressing IGF-1R itself and Akt expression. Consistent with previous work, induction of IGFBP-3 by SCH66336 also contributed in part to the anti-invasive effect. SCH66336 treatment also reduced the expression and activity of the urokinase-type plasminogen activator (uPA) and matrix metalloproteinase 2 (MMP-2), both important regulators of tumor metastasis. The effect of SCH66336 on uPA activity was inhibited partly by knockdown of IGFBP-3 using small interfering RNA. The inhibitory effect of SCH66336 on migration or invasion was attenuated partly or completely by knockdown of IGFBP-3, Akt or IGF-1R expression, respectively. Our results demonstrate that the IGF-1R pathway plays a major role in the proliferation, migration and invasion of HNSCC cells, suggesting that therapeutic obstruction of the IGF-1R pathway would be a useful approach to treating patients with HNSCC.

Topics: Animals; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Movement; Farnesyltranstransferase; Female; Head and Neck Neoplasms; Humans; Insulin-Like Growth Factor Binding Protein 3; Matrix Metalloproteinase 2; Mice; Mice, Nude; Neoplasm Invasiveness; Neoplasm Metastasis; Piperidines; Proto-Oncogene Proteins c-akt; Pyridines; Receptor, IGF Type 1; RNA Interference; RNA, Small Interfering; Squamous Cell Carcinoma of Head and Neck; Urokinase-Type Plasminogen Activator

Topics: Animals; Child, Preschool; Clinical Trials as Topic; Enzyme Inhibitors; Farnesyltranstransferase; Foundations; Humans; Lamin Type A; Mice; Mutation; Patient Selection; Piperidines; Progeria; Pyridines; Uncertainty; United States; United States Public Health Service

Topics: Child; Crowdsourcing; Drug Repositioning; Humans; National Institutes of Health (U.S.); Piperidines; Progeria; Pyridines; United States

AZD3409 is a novel DPTI that has potent activity against both FTase and GGTase-1. The in vitro inhibition profile of AZD3409 was characterized using three different cell lines: mouse embryogenic fibroblasts, transfected with H-Ras(V12) (MEF), A549 cells (Ki4B-Ras mutation) and MCF-7 cells (no Ras mutation).. Both cytotoxicity and levels of inhibition of farnesylation and geranylgeranylation were determined in different assays in relation to the concentration of AZD3409. Results were compared with those obtained with the first-generation FTase inhibitor lonafarnib or the GGTase-1 inhibitor GGTI-2147.. The mean IC(50) for cytotoxicity of AZD3409 and lonafarnib was 510 and 15,200 nM in MEF cells, 10,600 and 2,740 nM in A549 cells and 6,170 and 9,490 nM in MCF7 cells, respectively. In these cells, the IC(50) for FTase activity of AZD3409 ranged from 3.0 to 14.2 nM and of lonafarnib from 0.26 to 31.3 nM. The inhibiting activity of AZD3409 and lonafarnib on general protein farnesylation was comparable with the specific farnesylation levels of HDJ-2. In vitro geranylgeranylation of Rap1a could be inhibited by GGTI-2147 in all three cell lines, but only in MCF-7 cells by AZD3409. These results are in agreement with the IC(50) values for GGTase-1 activity as the lowest IC(50) for AZD3409 was found in the MCF-7 cell line.. AZD3409 inhibits farnesylation to a higher extent than geranylgeranylation. Both inhibition of farnesylation and geranylgeranylation could not be correlated to the antiproliferative activity of the drug.

Topics: Alkyl and Aryl Transferases; Animals; Cell Line, Tumor; Cell Proliferation; Dimethylallyltranstransferase; Farnesyltranstransferase; Fibroblasts; Humans; Imidazoles; Inhibitory Concentration 50; Leucine; Mice; Mutation; Piperidines; Pyridines; ras Proteins; Transfection

Farnesyl transferase inhibitors (FTIs) inhibit the farnesylation of proteins, including RAS and RHEB (Ras homolog enriched in brain). RAS signals to the RAF-MEK-ERK (MAPK) and PI3K-AKT-mTOR (AKT) signaling pathways, which have a major role in melanoma progression. RHEB positively regulates mammalian target of rapamycin (mTOR). We investigated the effects of the FTI lonafarnib alone and in combination with MAPK (mitogen-activated protein kinase) or AKT (acutely transforming retrovirus AKT8 in rodent T-cell lymphoma) pathway inhibitors on proliferation, survival, and invasive tumor growth of melanoma cells. Lonafarnib alone did not sufficiently inhibit melanoma cell growth. Combinations of lonafarnib with AKT pathway inhibitors did not significantly increase melanoma cell growth inhibition. In contrast, combinations of lonafarnib with MAPK pathway inhibitors yielded additional growth-inhibiting effects. In particular, the combination of the FTI lonafarnib with the pan-RAF inhibitor sorafenib synergistically inhibited melanoma cell growth, significantly enhanced sorafenib-induced apoptosis, and completely suppressed invasive tumor growth in monolayer and organotypic cultures, respectively. Apoptosis induction was associated with upregulation of the endoplasmic reticulum stress-related transcription factors p8 and CHOP (CAAT/enhancer binding protein (C/EBP) homologous protein), and downregulation of the antiapoptotic Bcl-2 (B-cell lymphoma-2) family protein Mcl-1(myeloid cell leukemia 1). Lonafarnib did not affect MAPK and AKT but did affect mTOR signaling. Together, these findings suggest that the FTI lonafarnib inhibits mTOR signaling and enforces sorafenib-induced apoptosis in melanoma cells and may therefore represent an effective alternative for melanoma treatment.

Topics: Antineoplastic Agents; Apoptosis; Basic Helix-Loop-Helix Transcription Factors; Benzenesulfonates; Cell Line, Tumor; Endoplasmic Reticulum; Farnesyltranstransferase; Humans; Melanoma; Mitogen-Activated Protein Kinase Kinases; Myeloid Cell Leukemia Sequence 1 Protein; Neoplasm Proteins; Niacinamide; Phenylurea Compounds; Piperidines; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Pyridines; Signal Transduction; Skin Neoplasms; Sorafenib; TOR Serine-Threonine Kinases; Transcription Factor CHOP

Malignant gliomas are highly lethal tumors resistant to current therapies. The standard treatment modality for these tumors, surgical resection followed by radiation therapy and concurrent temozolomide, has demonstrated activity, but development of resistance and disease progression is common. Although oncogenic Ras mutations are uncommon in gliomas, Ras has been found to be constitutively activated through the action of upstream signaling pathways, suggesting that farnesyltransferase inhibitors may show activity against these tumors. We now report the in vitro and orthotopic in vivo results of combination therapy using radiation, temozolomide and lonafarnib (SCH66336), an oral farnesyl transferase inhibitor, in a murine model of glioblastoma. We examined the viability, proliferation, farnesylation of H-Ras, and activation of downstream signaling of combination-treated U87 cells in vitro. Lonafarnib alone or in combination with radiation and temozolomide had limited tumor cell cytotoxicity in vitro although it did demonstrate significant inhibition in tumor cell proliferation. In vivo, lonafarnib alone had a modest ability to inhibit orthotopic U87 tumors, radiation and temozolomide demonstrated better inhibition, while significant anti-tumor activity was found with concurrent lonafarnib, radiation, and temozolomide, with the majority of animals demonstrating a decrease in tumor volume. The use of tumor neurospheres derived from freshly resected adult human glioblastoma tissue was relatively resistant to both temozolomide and radiation therapy. Lonafarnib had a significant inhibitory activity against these neurospheres and could potentate the activity of temozolomide and radiation. These data support the continued research of high grade glioma treatment combinations of farnesyl transferase inhibitors, temozolomide, and radiation therapy.

Topics: Animals; Antineoplastic Agents, Alkylating; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Dacarbazine; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Synergism; Glioma; Humans; Mice; Neoplasm Transplantation; Piperidines; Prenylation; Pyridines; Radiation, Ionizing; ras Proteins; Signal Transduction; Temozolomide; Time Factors

The shortage of geranylgeranyl-pyrophosphate (GGPP) was associated to an increased IL-1β release in the autoinflammatory syndrome mevalonate kinase deficiency (MKD), a rare inherited disease that has no specific therapy. Farnesyltransferase inhibitors (FTIs) act at the end of mevalonate pathway. Two FTIs, tipifarnib (Tip) and lonafarnib (Lon), were therefore evaluated as possible therapeutical choices for the treatment of MKD. FTIs could lead to a redirection of the limited available number of mevalonate intermediates preferentially to GGPP synthesis, eventually preventing the uncontrolled inflammatory response. The effect of Tip and Lon on intracellular cholesterol level (ICL) and on proinflammatory cytokines secretion was evaluated in a cellular model of MKD, chemically obtained treating RAW 264.7 cells with lovastatin (Lova) and alendronate (Ald). The combination of FTIs with the isoprenoid geraniol (GOH) was also tested both in this model and in monocytes isolated from MKD patients. Tip and Lon proved to revert the ICL lowering and to significantly reduce the lipopolysaccharide-induced cytokines secretion in Ald-Lova -RAW 264.7 cells. This anti-inflammatory effect was amplified combining the use of GOH with FTIs. The effect of GOH and Tip was successfully replicated in MKD patients' monocytes. Tip and Lon showed a dramatic anti-inflammatory effect in monocytes where mevalonate pathway was chemically or genetically impaired.

Topics: Acyclic Monoterpenes; Alendronate; Animals; Anti-Inflammatory Agents; Cell Line; Child; Child, Preschool; Cholesterol; Cytokines; Dose-Response Relationship, Drug; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Inflammation Mediators; Lovastatin; Male; Mevalonate Kinase Deficiency; Mice; Monocytes; Phosphotransferases (Alcohol Group Acceptor); Piperidines; Polyenes; Polyisoprenyl Phosphates; Polyunsaturated Alkamides; Pyridines; Quinolones; Terpenes

The purpose of this work is to study mechanisms underlying anti-tumor effects of farnesyltransferase inhibitors (FTIs) in non-small cell lung cancer (NSCLC). We demonstrate that mRNA and protein levels of Ras homologue enriched in brain (Rheb) are highly expressed both in NSCLC tissues and in NSCLC cell lines. Rheb expression levels correlate with phosphorylation of its downstream target S6 and the sensitivity of NSCLC cells to FTIs (R115777 and SCH66336)-induced growth inhibition and apoptosis. FTIs effectively and preferentially inhibited Rheb downstream signaling in NSCLC cells. Moreover, inhibition of Rheb functions by FTIs or dominant-negative Rheb mutants enhance the effects of cisplatin on NSCLC cells. Rheb-CSVL, a FTIs-resistant mutant, reduces the effects of FTIs on NSCLC cells. Our results suggest that Rheb is a critical target for FTIs therapy in NSCLC.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Cisplatin; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Lung Neoplasms; Mechanistic Target of Rapamycin Complex 1; Monomeric GTP-Binding Proteins; Multiprotein Complexes; Mutation; Neuropeptides; Phosphorylation; Piperidines; Prenylation; Proteins; Pyridines; Quinolones; Ras Homolog Enriched in Brain Protein; Ribosomal Protein S6; RNA Interference; RNA, Messenger; Signal Transduction; TOR Serine-Threonine Kinases; Transcription Factors; Transfection

The cytoplasmic deacetylase HDAC6 is an important regulator of cellular pathways that include response to stress, protein folding, microtubule stability, and cell migration, thus representing an attractive target for cancer chemotherapy. However, little is known about its upstream regulation. Our previous work has implicated HDAC6 as a new protein target for the farnesyltransferase inhibitors (FTIs), although HDAC6 lacks a farnesylation motif. Here we show that the protein farnesyltransferase (FTase) and HDAC6 are present in a protein complex together with microtubules in vivo and in vitro. FTase binds microtubules directly via its alpha subunit, and this association requires the C terminus of tubulin. Treatment with an FTI removed FTase, but not HDAC6, from the protein complex, suggesting that the active form of FTase is bound to microtubules. Importantly, the removal of FTase from microtubules abrogated HDAC6 activity, as did a stable knockdown of the alpha subunit of FTase (FTalphaKD). Interestingly, the FTalphaKD cells showed increased sensitivity to the antiproliferative effects of Taxol and the FTI lonafarnib when used either as single agents or in combination as compared with parental cells. Altogether, these data suggest that FTase, via its tubulin-association, is a critical upstream regulator of HDAC6 activity and that FTase expression could help stratify cancer patients that would most benefit from this treatment.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents, Phytogenic; Cell Line; Cell Line, Tumor; Cell Proliferation; Cytoplasm; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Histone Deacetylase 6; Histone Deacetylases; Humans; Microtubules; Models, Biological; Paclitaxel; Piperidines; Pyridines; Time Factors

Lonafarnib is a potent, selective farnesyltransferase inhibitor (FTI) undergoing clinical studies for the treatment of solid tumors and hematological malignancies. Preclinically, a number of FTIs, including lonafarnib, interact with taxanes to inhibit cancer cell growth in an additive/synergistic manner. These observations provided rationale for investigating the effects of combining lonafarnib and docetaxel on preclinical prostate cancer models. To date, docetaxel is the only chemotherapeutic agent in clinical use for hormone-refractory prostate cancer. In vitro experiments with 22Rv1, LNCaP, DU-145, PC3 and PC3-M prostate cancer cell lines showed significantly enhanced inhibition of cell proliferation and apoptosis when lonafarnib was added to docetaxel. In human tumor xenograft models, continuous coadministration of lonafarnib with docetaxel caused marked tumor regressions (24-47%) in tumors from all of the cell types as well as parental CWR22 xenografts. Intermittent dosing of lonafarnib (5 days on then 5 days off) coadministered with docetaxel produced similar regressions in hormone-refractory 22Rv1 tumors. 22Rv1 tumors progressing on docetaxel treatment also responded to treatment with intermittent lonafarnib (5 days on then 5 days off). Moreover, animals did not exhibit any signs of toxicity during coadministration of lonafarnib and docetaxel. In conclusion, coadministration of continuous and intermittent lonafarnib enhanced the antitumor activity of docetaxel in a panel of prostate cancer models. An intermittent dosing schedule of lonafarnib coadministered with docetaxel may allow enhanced efficacy to that of continuous dosing by improving the tolerability of higher doses of lonafarnib.

Topics: Animals; Antineoplastic Agents; Blotting, Western; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Docetaxel; Drug Synergism; Drug Therapy, Combination; Humans; Male; Mice; Mice, Nude; Mice, SCID; Neoplasms, Hormone-Dependent; Piperidines; Prostatic Neoplasms; Pyridines; Taxoids; Xenograft Model Antitumor Assays

Temozolomide (TMZ) exerts its cytotoxic effects by methylating guanine in DNA, resulting in a mismatch with thymine. We studied possible enhancement of the cytotoxic activity of several other targeted drugs in four lung cancer cell lines by TMZ. the data are in relation to O(6)-alkylguanine-DNA-alkyltransferase (AGT) expression, gene methylation, cell cycle distribution and adduct formation. Synergism/additivity was found with O(6)-BG), gemcitabine, lonafarnib and paclitaxel, but not with platinum analogs and topoisomerase-inhibitors. O(6)-BG enhanced TMZ-induced accumulation in the G2/m-phase by increasing formation and retention of the O(6)-methyldeoxyguanosine adducts. TMZ combinations with drugs showing a different individual effect on the cell cycle (e.g. gemcitabine-induced S-phase) were most effective. The results show that O(6)-BG enhanced the TMZ effect in all cell lines. TMZ enhanced the cytotoxicity of gemcitabine, paclitaxel and lonafarnib in most cell lines, possibly by affecting the cell cycle, supporting possible application of TMZ in the treatment of lung cancer.

Topics: Animals; Antineoplastic Agents, Alkylating; Carcinoma, Non-Small-Cell Lung; Cell Cycle; Cell Line, Tumor; Dacarbazine; Deoxycytidine; Deoxyguanosine; DNA Adducts; DNA Methylation; Drug Synergism; Gemcitabine; Humans; Lung Neoplasms; Mice; O(6)-Methylguanine-DNA Methyltransferase; Paclitaxel; Piperidines; Pyridines; Temozolomide

KRAS mutations are currently the most frequently mutated oncogenes in non-small cell lung cancers (NSCLC). A growing body of evidence suggests that targeting RAS could be an efficient strategy in NSCLC. Several approaches have been developed to target either RAS protein or downstream effectors such as RAF or MEK. First clinical trials evaluating farnesyltransferases inhibitors have led to unsuccessful results. However, targeting RAF and MEK could be a more efficient approach in NSCLC.

Topics: Animals; Antineoplastic Agents; Benzenesulfonates; Carcinoma, Non-Small-Cell Lung; Farnesyltranstransferase; Genes, ras; Humans; Lung Neoplasms; Mice; Mitogen-Activated Protein Kinase Kinases; Mutation; Neoplasm Proteins; Niacinamide; Phenylurea Compounds; Piperidines; Pyridines; Quinolones; raf Kinases; ras Proteins; Sorafenib

The AKT-mTOR pathway harbors several known and putative oncogenes and tumor suppressors. In a phenotypic screen for lymphomagenesis, we tested candidate genes acting upstream of and downstream from mTOR in vivo. We find that Rheb, a proximal activator of mTORC1, can produce rapid development of aggressive and drug-resistant lymphomas. Rheb causes mTORC1-dependent effects on apoptosis, senescence, and treatment responses that resemble those of Akt. Moreover, Rheb activity toward mTORC1 requires farnesylation and is readily blocked by a pharmacological inhibitor of farnesyltransferase (FTI). In Pten-deficient tumor cells, inhibition of Rheb by FTI is responsible for the drug's anti-tumor effects, such that a farnesylation-independent mutant of Rheb renders these tumors resistant to FTI therapy. Notably, RHEB is highly expressed in some human lymphomas, resulting in mTORC1 activation and increased sensitivity to rapamycin and FTI. Downstream from mTOR, we examined translation initiation factors that have been implicated in transformation in vitro. Of these, only eIF4E was able to enhance lymphomagenesis in vivo. In summary, the Rheb GTPase is an oncogenic activity upstream of mTORC1 and eIF4E and a direct therapeutic target of farnesyltransferase inhibitors in cancer.

Topics: Animals; Antibiotics, Antineoplastic; Blotting, Western; Cell Transformation, Neoplastic; Cells, Cultured; Cellular Senescence; Doxorubicin; Eukaryotic Initiation Factor-4E; Farnesyltranstransferase; Female; Fibroblasts; Gene Dosage; Humans; Immunophenotyping; Immunosuppressive Agents; Lymphoma; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred C57BL; Mice, Knockout; Monomeric GTP-Binding Proteins; Multiprotein Complexes; Neuropeptides; Phosphorylation; Piperidines; Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-myc; PTEN Phosphohydrolase; Pyridines; Ras Homolog Enriched in Brain Protein; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Transcription Factors; Tumor Suppressor Protein p53

The mechanisms of action of farnesyltransferase inhibitors (FTIs) involve Rheb and the phosphatidylinositide 3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway. mTOR in particular plays a key role in the regulation of autophagy. Collectively, the literature suggests that FTIs very likely induce autophagy, but thus far there have been no reports that FTIs affect this process relevant to cancer cell biology. We hypothesized that FTIs can induce autophagy. In this study, we found that the FTIs manumycin A, FTI-276, and lonafarnib induced autophagy in two human cancer cell lines. We also found that neither inhibition of apoptosis with a pan-caspase inhibitor nor inhibition of autophagy increased the number of clones of lonafarnib-treated U2OS osteosarcoma cells that formed in soft agar. Although whether autophagy is a cell death or cell survival mechanism after FTI treatment remains unresolved, our data show that cancer cells apparently can shift between apoptosis and autophagy once they are committed to die after FTI treatment.

Topics: Apoptosis; Autophagy; Cell Line, Tumor; Dose-Response Relationship, Drug; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Microscopy, Electron, Transmission; Microscopy, Fluorescence; Pancreatic Neoplasms; Piperidines; Polyenes; Polyunsaturated Alkamides; Protein Kinases; Pyridines; RNA, Small Interfering; Signal Transduction; TOR Serine-Threonine Kinases

3D-QSAR analysis of a set of 37 analogues of SCH 66336 (Sarasar) was performed by most widely used computational tool, molecular field analysis (MFA) to investigate the substitutional requirements for the favorable receptor-drug interaction and to derive a predictive model that may be used for the designing of a novel farnesyltransferase inhibitors (FTIs). Regression analysis was carried out using genetic partial least squares (G/PLS) method. A highly predictive and statistically significant model was generated. The predictive ability of the model developed was assessed using a test set of six compounds (r(2)(pred) as high as 0.791). The analyzed MFA model has demonstrated a good fit, having r(2) value of 0.967 and cross-validated coefficient r(2)(cv) value as 0.921.

Topics: Drug Evaluation, Preclinical; Farnesyltranstransferase; Least-Squares Analysis; Models, Molecular; Molecular Conformation; Piperidines; Pyridines; Quantitative Structure-Activity Relationship; Regression Analysis; Reproducibility of Results

Signal transducer and activators of transcription 3 (STAT3) is an important transcription factor that is essential for lung cancer cell survival. STAT3 is activated by diverse upstream receptor and nonreceptor tyrosine kinases, and blockade of STAT3 results in tumor growth inhibition. Therefore, a search for STAT3 inhibitors is under way. We demonstrate that SCH66336, at 4 mumol/l, completely blocks STAT3 phosphorlyation in a variety of nonsmall cell lung carcinoma (NSCLC) cell lines, whereas the effect on AKT and extracellular signal-regulated kinase activation is variable. Furthermore, SCH66336 has antiproliferative effects on NSCLC cells. When NSCLC cells are exposed sequentially to SCH66336 and a small molecule dual tyrosine kinase inhibitor of epidermal growth factor receptor and human epidermal growth factor receptor 2, synergistic activity is observed with an increase in the fraction of cells undergoing apoptosis. Concurrent exposure to both agents is, however, associated with antagonism and decreased apoptosis. We conclude that blockade of STAT3 phosphorylation might be one of the mechanisms by which SCH66336 exerts its antitumor activity, and that this can be synergistic in vitro when administered sequentially with epidermal growth factor receptor inhibitors.

Topics: Apoptosis; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Colorimetry; Drug Synergism; Flow Cytometry; Humans; Indicators and Reagents; Lapatinib; Mutation; Oncogene Protein v-akt; Piperidines; Prenylation; Pyridines; Quinazolines; Receptor, ErbB-2; Signal Transduction; STAT3 Transcription Factor

To determine the effects of combining lonafarnib with paclitaxel on the growth of human ovarian cancer cells and tumor xenografts as well as to monitor a pharmacodynamic marker of farnesyltransferase inhibition (HDJ-2) in peripheral blood mononuclear cells (PBMCs) isolated from tumor-bearing animals after treatment with this combination.. Proliferation of A2780, PA-1, IGROV-1, and TOV-112D cells was assessed after treatment with lonafarnib and paclitaxel. Cell cycle progression was determined by flow cytometry, and apoptosis was evaluated by assaying for caspase-3 and cleaved PARP. The effects of lonafarnib and paclitaxel on the tumor growth of each model were determined in immunocompromised mice. Proteins extracted from cells, tumors, and PBMCs were assayed for HDJ-2 mobility shifts by Western blotting as well as for farnesyl protein transferase (FTase) enzyme activity by biochemical analyses.. In A2780, PA-1, IGROV-1, and TOV-112D cells lonafarnib potentiated the growth inhibitory effects of paclitaxel. In each of the models lonafarnib enhanced paclitaxel-induced mitotic arrest and apoptosis. The combination of lonafarnib plus paclitaxel resulted in marked tumor regressions in A2780, TOV-112D, PA-1, and IGROV-1 tumor xenografts. Western blotting demonstrated that in PBMCs isolated from the animals, paclitaxel treatment suppressed lonafarnib-induced HDJ-2 mobility shifts. Paclitaxel did not affect lonafarnib inhibition of FTase enzyme activity levels in these PBMCs.. Lonafarnib enhances the antiproliferative effects of paclitaxel on ovarian cancer cells in vitro and ovarian tumor xenografts in vivo. Measuring FTase enzyme activity levels rather than HDJ-2 shifts in PBMCs may be a more accurate biomarker to predict levels of farnesyltransferase inhibition in patients who are also receiving paclitaxel chemotherapy.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Biomarkers, Tumor; Cell Cycle; Cell Growth Processes; Cell Line, Tumor; Dose-Response Relationship, Drug; Drug Synergism; Farnesyltranstransferase; Female; HSP40 Heat-Shock Proteins; Humans; Leukocytes, Mononuclear; Mice; Mice, Nude; Mice, SCID; Ovarian Neoplasms; Paclitaxel; Piperidines; Pyridines; Xenograft Model Antitumor Assays

Although preclinical studies have suggested that farnesyltransferase inhibitors (FTI) have promising antitumor activity, clinical trials have shown that FTI activity in patients is actually limited. The mechanism that induces resistance to FTI treatment is still not fully understood. The FTI SCH66336 has been shown to induce apoptotic and antiangiogenic activities in a subset of head and neck squamous cell carcinoma (HNSCC) and non-small cell lung cancer (NSCLC) cell lines. We therefore investigated the mechanisms mediating resistance to the therapeutic activities of SCH66336 in HNSCC and NSCLC. Our various analyses showed that insulin-like growth factor-I receptor (IGF-IR) activation interferes with the antitumor activity of SCH66336 in HNSCC and NSCLC cells. Treatment with SCH66336 activated the IGF-IR/phosphatidylinositol 3-kinase/Akt pathway, leading to increased mammalian target of rapamycin (mTOR)-mediated protein synthesis of survivin in a subset of HNSCC and NSCLC cell lines that were insensitive to the apoptotic activities of the drug. Inhibition of IGF-IR, Akt, or mTOR or the knockdown of survivin expression abolished resistance to SCH66336 and induced apoptosis in the cells. Overexpression of survivin by the use of adenoviral vector protected SCH66336-sensitive HNSCC cells from the apoptotic activities of the drug. Our results suggest that expression of phosphorylated IGF-IR, phosphorylated Akt, phosphorylated mTOR, and survivin serves as biological markers of SCH66336 responsiveness in HNSCC and NSCLC cells and that SCH66336 induces survivin expression through an IGF-IR/Akt/mTOR-dependent pathway. Thus, combining inhibitors of IGF-IR, phosphatidylinositol 3-kinase/Akt, mTOR, or survivin with SCH66336 may be an effective anticancer therapeutic strategy for patients with HNSCC or NSCLC.

Topics: Apoptosis; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Cell Cycle; Drug Resistance, Neoplasm; Head and Neck Neoplasms; Humans; Inhibitor of Apoptosis Proteins; Lung Neoplasms; Microtubule-Associated Proteins; Neoplasm Proteins; Phosphatidylinositol 3-Kinases; Phosphorylation; Piperidines; Protein Kinases; Proto-Oncogene Proteins c-akt; Pyridines; Receptor, IGF Type 1; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Survivin; TOR Serine-Threonine Kinases; Tumor Cells, Cultured

Farnesyl protein transferase (FPT) inhibition is an interesting and promising approach to noncytotoxic anticancer therapy. Research in this area has resulted in several orally active compounds that are in clinical trials. Electrospray ionization (ESI) time-of-flight mass spectrometry (TOF-MS) was used for the direct detection of a 95 182 Da pentameric noncovalent complex of alpha/beta subunits of FPT containing Zn, farnesyl pyrophosphate (FPP) and SCH 66336, a compound currently undergoing phase III clinical trials as an anticancer agent. It was noted that the desalting of protein samples was an important factor in the detection of the complex. This study demonstrated that the presence of FPP in the system was necessary for the detection of the FPT-inhibitor complex. No pentameric complex was detected in the spectrum when the experiment was carried out in the absence of the FPP. An indirect approach was also applied to confirm the noncovalent binding of SCH 66336 to FPT by the use of an off-line size exclusion chromatography followed by liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) for the detection of the inhibitor.

Topics: Alkyl and Aryl Transferases; Chromatography, Gel; Enzyme Inhibitors; Mass Spectrometry; Molecular Weight; Piperidines; Protein Denaturation; Pyridines; Spectrometry, Mass, Electrospray Ionization

We have used a mouse model based on overexpression of c-Myc in B cells genetically engineered to be self-reactive to test the hypothesis that farnesyl transferase inhibitors (FTIs) can effectively treat mature B cell lymphomas. FTIs are undergoing clinical trials to treat both lymphoid and non-lymphoid malignancies and we wished to obtain evidence to support the inclusion of B cell lymphomas in future trials.. We report that two FTIs, L-744,832 and SCH66336, blocked the growth of mature B cell lymphoma cells in vitro and in vivo. The FTI treatment affected the proliferation and survival of the transformed B cells to a greater extent than naïve B cells stimulated with antigen. In syngeneic mice transplanted with the transgenic lymphoma cells, L-744,832 treatment prevented the growth of the tumor cells and the morbidity associated with the resulting lymphoma progression. Tumors that arose from transplantation of the lymphoma cells regressed with as little as three days of treatment with L-744,832 or SCH66336. Treatment of these established lymphomas with L-744,832 for seven days led to long-term remission of the disease in approximately 25% of animals.. FTI treatment can block the proliferation and survival of self-reactive transformed B cells that overexpress Myc. In mice transplanted with mature B cell lymphomas, we found that FTI treatment led to regression of disease. FTIs warrant further consideration as therapeutic agents for mature B cell lymphomas and other lymphoid tumors.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Enzyme Inhibitors; Farnesyltranstransferase; Flow Cytometry; Lymphocytes; Lymphoma, B-Cell; Methionine; Mice; Mice, Inbred C57BL; Mice, Transgenic; Piperidines; Pyridines; Remission Induction

Clinical studies have suggested that bisphosphonates may prolong the survival of sub-sets of myeloma patients. Newer nitrogen containing bisphosphonates such as zoledronate act, at least in part, by inhibiting farnesyl diphosphate synthase and subsequent protein prenylation, furthermore, limited data suggests that zoledronate exerts a direct anti-tumour effect against human myeloma cell lines. We therefore investigated the anti-myeloma potential of zoledronate in comparison to, and in combination with, two other inhibitors of the mevalonate pathway: the HMGCoA reductase inhibitor fluvastatin and the farnesyl transferase inhibitor SCH66336. We found that fluvastatin was able to inhibit the proliferation of myeloma cells more effectively than zoledronate or SCH66336 and that combinations of zoledronate and fluvastatin, but not zoledronate and SCH66336 acted synergistically. Our data indicated that the anti-proliferative effect of mevalonate pathway inhibitors is mediated principally via prevention of geranylgeranylation and is the result of both cell cycle arrest and apoptosis induction. Microarray and quantitative real-time PCR analyses further demonstrated that genes related to apoptosis, cell cycle control, and the mevalonate pathway were particularly affected by zoledronate and fluvastatin, and that some of these genetic effects were synergistic. We conclude that the mechanisms of geranylgeranylation inhibition mediated anti-myeloma effects warrant further evaluation and may provide novel targets for future therapeutic development.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Cell Survival; Diphosphonates; Drug Screening Assays, Antitumor; Fatty Acids, Monounsaturated; Fluvastatin; Humans; Imidazoles; Indoles; Mevalonic Acid; Multiple Myeloma; Piperidines; Pyridines; Structure-Activity Relationship; Zoledronic Acid

Pre-clinical studies have demonstrated that farnesyltransferase inhibitors (FTIs) induce growth arrest or apoptosis in various human cancer cells independently of Ras mutations. However, the underlying mechanism remains unknown. Death receptor 5 (DR5) is a pro-apoptotic protein involved in mediating the extrinsic apoptotic pathway. Its role in FTI-induced apoptosis has not been reported. In this study, we investigated the modulation of DR5 by the FTI lonafarnib and the involvement of DR5 up-regulation in FTI-induced apoptosis. Lonafarnib activated caspase-8 and its downstream caspases, whereas the caspase-8-specific inhibitor benzyloxycarbonyl-Ile-Glu(methoxy)-Thr-Asp(methoxy)-fluoromethyl ketone or small interfering RNA abrogated lonafarnib-induced apoptosis, indicating that lonafarnib induces caspase-8-dependent apoptosis. Lonafarnib up-regulated DR5 expression, increased cell-surface DR5 distribution, and enhanced tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis. Overexpression of a dominant-negative Fas-associated death domain mutant or silencing of DR5 expression using small interfering RNA attenuated lonafarnib-induced apoptosis. These results indicate a critical role of the DR5-mediated extrinsic apoptotic pathway in lonafarnib-induced apoptosis. By analyzing the DR5 promoter, we found that lonafarnib induced a CCAAT/enhancer-binding protein homologous protein (CHOP)-dependent transactivation of the DR5 promoter. Lonafarnib increased CHOP expression, whereas silencing of CHOP expression abrogated lonafarnib-induced DR5 expression. These results thus indicate that lonafarnib induces CHOP-dependent DR5 up-regulation. We conclude that CHOP-dependent DR5 up-regulation contributes to lonafarnib-induced apoptosis.

Topics: Apoptosis; Caspase 8; Cell Line, Tumor; Farnesyltranstransferase; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Membrane Proteins; Piperidines; Pyridines; Receptors, TNF-Related Apoptosis-Inducing Ligand; Recombinant Proteins; TNF-Related Apoptosis-Inducing Ligand; Transcription Factor CHOP; Up-Regulation

Mutation in the target oncoprotein is a common mechanism of resistance to tyrosine kinase inhibitors, as exemplified by the many BCR/ABL mutations that thwart imatinib activity in patients with chronic myelogenous leukemia. It remains unclear whether normal cellular protein targets of chemotherapeutics will evolve drug resistance via mutation to a similar extent. We conducted an in vitro screen for resistance to lonafarnib, a farnesyl protein transferase inhibitor that blocks prenylation of a number of proteins important in cell proliferation, and identified 9 mutations clustering around the lonafarnib binding site. In patients treated with a combination of imatinib and lonafarnib, we identified farnesyl protein transferase mutations in residues identified in our screen. Substitutions at Y361 were found in patients prior to treatment initiation, suggesting that these mutants might confer a proliferative advantage to leukemia cells, which we were able to confirm in cell culture. In vitro mutagenesis of normal cellular enzymes can be exploited to identify mutations that confer chemotherapy resistance to novel agents.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzamides; Cell Proliferation; Drug Resistance, Neoplasm; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Imatinib Mesylate; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Mice; Mutagenesis; Mutagenesis, Site-Directed; Mutation; Pilot Projects; Piperazines; Piperidines; Protein Conformation; Protein Prenylation; Pyridines; Pyrimidines; Tumor Cells, Cultured

Several cytoplasmic proteins, such as GTPases of the Ras family, containing a C-terminal CAAX motif are prenylated by farnesyltransferase to facilitate localization to cellular membranes where activation occurs. Farnesyltransferase inhibitors (FTIs) interfere with this farnesylation process, thereby preventing proper membrane localization and rendering the proteins unavailable for activation. Currently, FTIs are being explored as antineoplastic agents for the treatment of several malignancies. However, since farnesylated proteins like Ras are also involved in intracellular signaling in lymphocytes, FTIs might interfere with T-cell activation. Based on this hypothesis we examined the effect of several FTIs on cytokine production in response to anti-CD3 + anti-CD28 monoclonal antibodies or PMA + ionomycin. Murine Th1 and Th2 clones, stimulated in the presence of FTIs, showed a dose-dependent reduction of lineage-specific cytokine secretion (IFN-gamma, IL-2, IL-4, IL-5). However, no inhibition of ERK or JNK MAP kinases was observed, nor was induction of cytokine mRNA affected. Rather, intracellular cytokine protein synthesis was blocked. Inhibition of human T-cell INF-gamma production also was observed, correlating with reduced phosphorylation of p70S6K. These results indicate that FTIs inhibit T-cell activation at the posttranscriptional level and also suggest that they may have potential as novel immunosuppressive agents.

Topics: Antibodies, Monoclonal; Blotting, Western; CD28 Antigens; CD3 Complex; Cells, Cultured; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Farnesyltranstransferase; HSP40 Heat-Shock Proteins; Humans; Interferon-gamma; Interleukin-2; Interleukin-4; Lymphocyte Activation; MAP Kinase Kinase 4; Methionine; Phosphorylation; Piperidines; Protein Prenylation; Pyridines; Quinolones; Ribonuclease, Pancreatic; Ribosomal Protein S6 Kinases, 70-kDa; RNA Processing, Post-Transcriptional; T-Lymphocytes; Th1 Cells; Th2 Cells

Lonafarnib is an orally bioavailable farnesyltransferase inhibitor. Originally developed to block the membrane localization of Ras, subsequent work suggested that farnesyltransferase inhibitors mediate their antitumor activities by altering the biological activities of additional farnesylated proteins. Breast tumor models that express wild-type Ras have been shown to be sensitive to farnesyltransferase inhibitors. We have determined the effects of combining lonafarnib with the antiestrogen 4-hydroxy tamoxifen on hormone-dependent breast cancer cell lines in vitro. The effects of combining lonafarnib with tamoxifen or the aromatase inhibitor anastrozole on the growth of two different MCF-7 breast tumor xenograft models were also evaluated. In four of five human breast cancer cell lines, lonafarnib enhanced the antiproliferative effects of 4-hydroxy tamoxifen. The combination prevented MCF-7 cells from transitioning through the G1 to S phase of the cell cycle and augmented apoptosis. This was associated with reduced expression of E2F-1 and a reduction in hyperphosphorylated retinoblastoma protein. Lonafarnib plus 4-hydroxy tamoxifen also inhibited the mammalian target of rapamycin signal transduction pathway. In nude mice bearing parental MCF-7 or aromatase-transfected MCF-7Ca breast tumor xenografts, lonafarnib enhanced the antitumor activity of both tamoxifen and anastrozole. These studies indicate that lonafarnib enhances the efficacy of endocrine agents clinically used for treating hormone-dependent breast cancer.

Topics: Anastrozole; Animals; Antineoplastic Agents, Hormonal; Apoptosis; Aromatase Inhibitors; Blotting, Western; Breast Neoplasms; Cell Cycle; Cell Line, Tumor; Drug Synergism; Enzyme Inhibitors; Farnesyltranstransferase; Female; G1 Phase; Humans; In Situ Nick-End Labeling; Mice; Mice, Nude; Neoplasm Transplantation; Nitriles; Ovariectomy; Piperidines; Pyridines; S Phase; Tamoxifen; Triazoles

The farnesyl transferase inhibitor (FTI) SCH66336 has been shown to have antitumor activities in head and neck squamous cell carcinoma (HNSCC) in vitro and in vivo. However, its mechanism of action has not been well defined. Here, we report that the insulin-like growth factor (IGF) binding protein (IGFBP)-3 mediates antitumor activities of SCH66336 in HNSCC by inhibiting angiogenesis. SCH66336 significantly suppressed HNSCC tumor growth and angiogenesis via mechanisms that are independent of H-Ras and RhoB. By inducing IGFBP-3 secretion from HNSCC cells, this compound suppresses angiogenic activities of endothelial cells, including vessel formation in chorioallantoic membranes of chick, endothelial cell sprouting from chick aorta, and capillary tube formation of human umbilical vascular endothelial cells (HUVEC). Knockdown of IGFBP-3 expression in HNSCC cells by RNA interference or depletion of IGFBP-3 in HUVECs by neutralizing antibody effectively blocked the effects of IGFBP-3 secreted from SCH66336-treated HNSCC cells on HUVECs. These findings suggest that IGFBP-3 could be a primary target for antitumor activities of FTIs and that IGFBP-3 is an effective therapeutic approach against angiogenesis in HNSCC.

Topics: Animals; Aorta; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Cell Proliferation; Chickens; Chorioallantoic Membrane; Endothelium, Vascular; Enzyme Inhibitors; Farnesyltranstransferase; Female; Gene Expression Regulation, Neoplastic; Genes, ras; Head and Neck Neoplasms; Humans; Insulin-Like Growth Factor Binding Protein 3; Mice; Mice, Nude; Neovascularization, Pathologic; Piperidines; Pyridines; rhoB GTP-Binding Protein; Tumor Cells, Cultured; Umbilical Veins; Vascular Endothelial Growth Factor A

Lonafarnib (Sarasar), a farnesyl transferase inhibitor, is currently under development for the treatment of solid tumors. Incubation of lonafarnib with human liver microsomes resulted in the formation of four oxidative metabolites (M1, M2, M3, and M4). Minor to trace levels of these metabolites were detected in humans after multiple-dose administration of lonafarnib. Liquid chromatography-mass spectrometry analyses exhibited a mass to charge ratio (m/z) for the (M+H)(+) ion of M1, M2, M3, and M4 at 653, 635, 669, and 653 Th, respectively. These metabolites, respectively, resulted from changes of +O, -2H, +2O, and +O relative to lonafarnib. Recombinant human CYP3A4 and CYP3A5 exhibited catalytic activity with respect to the formation of M1, M2, and M3, whereas CYP2C8 exhibited catalytic activity with respect to the formation of M4. There was a high correlation between the formation of M1, determined in 10 human liver microsomal samples, and 6beta-hydroxylation of testosterone catalyzed by CYP3A4/5 (r = 0.93). The IC(50) values of ketoconazole for inhibition of M1 and M2 were 0.61 and 0.92 microM, respectively. The formation of M4 by human liver microsomes was inhibited 72% by 50 microM quercetin, suggesting that the formation of M4 was mediated via CYP2C8. A CYP3A4/5-specific inhibitory monoclonal antibody inhibited the formation of M1, M2, and M3 by 85, 75, and 100%, respectively. In conclusion, the formation of metabolites M1, M2, and M3 from lonafarnib was mediated via CYP3A4 and CYP3A5.

Topics: Antineoplastic Agents; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Enzyme Inhibitors; Humans; Ketoconazole; Microsomes, Liver; Oxidation-Reduction; Piperidines; Pyridines; Recombinant Proteins

Structural characterization of unstable metabolites and other drug-derived entities poses a serious challenge to the analytical chemist using instrumentation such as LC-MS and LC-MS/MS, and may lead to inaccurate identification of metabolite structures. The task of structural elucidation becomes even more difficult when an analyte is unstable in the ion source of the mass spectrometer. However, a judicious selection of the experimental conditions and the advanced features of new generation mass spectrometers can often overcome these difficulties. We describe here the identification of three drug-derived peaks (A, B and C) that were detected from a Schering-Plough developmental compound (Lonafarnib) following incubation with cDNA-expressed human CYP3A4. Definitive characterization was achieved using (1) accurate mass measurement, (2) stable isotope incorporation, (3) reduced ion source temperature, (4) alkali ion attachment and (5) MS/MS fragmentation studies. The protonated ions of compounds A and B fragmented almost completely in the source, yielding ions of the same mass-to-charge ratio (m/z) as that of protonated C (CH+). Fortunately, the presence of Na+ and K+ adducts of A and B provided information crucial to distinguishing AH+ and BH+ from their fragment ions. Metabolite A was shown to be an unstable hydroxylated metabolite of Lonafarnib. The metabolite C was shown to be a dehydrogenated metabolite of Lonafarnib (Lonafarnib-2H), unstable in the presence of protic solvents. Finally, B was artifactually formed most likely from C by the solvolytic addition of methanol during sample preparation. MS/MS fragmentation experiments assisted in identifying the site of metabolism in A and chemical modification in B. A and C readily interconvert through hydration/dehydration, and B and C through addition/elimination of methanol present in the sample-processing solvents. Finally, NMR experiments were performed to confirm the structures of A and C.

Topics: Carbon Isotopes; Chromatography, Liquid; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Drug Stability; Humans; Ions; Isotope Labeling; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Structure; Piperidines; Pyridines; Temperature

When multiple drugs are administered simultaneously, investigators are often interested in assessing whether the drug combinations are synergistic, additive, or antagonistic. Based on the Loewe additivity reference model, many existing response surface models require constant relative potency and some of them use a single parameter to capture synergy, additivity, or antagonism. However, the assumption of constant relative potency is too restrictive, and these models using a single parameter to capture drug interaction are inadequate to describe the phenomenon when synergy, additivity, and antagonism are interspersed in different regions of drug combinations. We propose a generalized response surface model with a function of doses instead of one single parameter to identify and quantify departure from additivity. The proposed model can incorporate varying relative potencies among multiple drugs as well. Examples and simulations are given to demonstrate that the proposed model is effective in capturing different patterns of drug interaction.

Topics: Antineoplastic Combined Chemotherapy Protocols; Biometry; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Survival; Data Interpretation, Statistical; Dose-Response Relationship, Drug; Drug Antagonism; Drug Interactions; Drug Synergism; Fenretinide; Humans; Models, Biological; Models, Statistical; Piperidines; Pyridines

Like Ras, farnesylation of the IP (prostacyclin receptor) is required for its efficient intracellular signalling, and hence the IP represents a potential target for inhibition by FTIs [FTase (farnesyl protein transferase) inhibitors]. Herein, the effect of SCH66336 on the isoprenylation and function of the human and mouse IPs overexpressed in human embryonic kidney 293 cells, and by the IP endogenously expressed in human erythroleukaemia cells, was investigated. SCH66336 yielded concentration-dependent decreases in IP-mediated cAMP generation (IC50 0.27-0.62 nM), [Ca2+]i mobilization (IC50 26.6-48.3 nM) and IP internalization, but had no effect on signalling by the non-isoprenylated beta2 adrenergic receptor or b isoform of the TP (prostanoid thromboxane A2 receptor). Additionally, SCH66336 impaired IP-mediated crossdesensitization of TPa signalling (IC50 56.1 nM) and reduced farnesylation of the molecular chaperone protein HDJ-2 (IC50 3.1 nM). To establish whether farnesylation of the IP is inhibited and/or whether its 'CaaX motif' might undergo alternative geranylgeranylation in the presence of SCH66336, a series of chimaeric Ha (Harvey)-Ras fusions were generated by replacing its CaaX motif (-CVLS) with that of the IP (-CSLC) or, as controls, of Ki (Kirsten)-Ras 4B (-CVIM) or Rac 1 (-CVLL). Whereas SCH66336 had no effect on Ha-RasCVLL isoprenylation in vitro or in whole cells, it supported alternative geranylgeranylation of Ha-RasCVIM, but completely impaired isoprenylation of both Ha-RasCVLS and Ha-RasCSLC. These data confirm that the -CSLC motif of the IP is a direct target for inhibition by the FTI SCH66336, and in the presence of strong FTase inhibition, the IP does not undergo compensatory geranylgeranylation

Topics: Adrenergic beta-Agonists; Alkyl and Aryl Transferases; Amino Acid Motifs; Animals; Calcium Signaling; Carrier Proteins; Cell Line; Cell Line, Tumor; Cyclic AMP; Dose-Response Relationship, Drug; Endocytosis; Epoprostenol; Farnesyltranstransferase; Heat-Shock Proteins; HSP40 Heat-Shock Proteins; Humans; Iloprost; Isoproterenol; Kidney; Leukemia, Erythroblastic, Acute; Mice; Mutagenesis, Site-Directed; Organophosphorus Compounds; Piperidines; Proline; Propanolamines; Protein Prenylation; Protein Processing, Post-Translational; Proto-Oncogene Proteins p21(ras); Pyridines; Receptors, Adrenergic, beta-2; Receptors, Epoprostenol; Receptors, Thromboxane A2, Prostaglandin H2; Recombinant Fusion Proteins; Signal Transduction; Transfection

The ras oncogenes are among those most frequently found in human cancers. Blocking Ras farnesylation is a promising strategy for arresting cancer growth. Ras activates several signaling pathways with key roles in cellular proliferation, invasion, metastasis and angiogenesis. Furthermore, proteolytic activities of matrix proteinases such as urokinase-type plasminogen activator (uPA) and matrix metalloproteinases (MMPs) are regulated by Ras isoforms. Thus, we investigated the effects of SCH-66336, a farnesyltransferase inhibitor, on secretion of components of the plasminogen activation system as well as on the gelatinases MMP-2 and MMP-9, which play pivotal roles in matrix remodeling. SCH-66336 up to 5 microM did not significantly alter the viability of prostate (PC-3) and renal (Caki-1) cancer cells incubated in serum-depleted medium. SCH-66336 partly inhibited the processing of H-Ras, while levels of mature N-Ras and K-Ras remained unaffected. Under these noncytotoxic conditions, uPA and tPA levels were lowered in culture medium but raised in cell lysates, suggesting inhibition of trafficking pathways. In contrast, SCH-66336 had no effect on uPAR expression or on secreted PAI-1 levels. As expected, the reduction of uPA and tPA activities by SCH-66336 inhibited the conversion of plasminogen to plasmin by about 25% in PC-3 cells. SCH-66336 also inhibited the levels of secreted pro-MMP-2 and pro-MMP-9 as well as the release of their inhibitors TIMP-1 and TIMP-2. SCH-66336 decreased both the adhesion and even more so the migration of PC-3 cells on gelatin. Thus, SCH-66336 inhibited farnesylation in both cancer cell types, and H-Ras functions should be reduced by the drug. In addition, the lower levels of secreted proteinases in the presence of SCH-66336 suggest that reduced matrix remodeling and cell migration should occur in treated tumors.

Topics: Alkyl and Aryl Transferases; Carcinoma; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Survival; Culture Media; Dose-Response Relationship, Drug; Down-Regulation; Electrophoresis, Polyacrylamide Gel; Enzyme Inhibitors; Farnesyltranstransferase; Fibrinolysin; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Immunoblotting; Kinetics; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Matrix Metalloproteinases; Piperidines; Plasminogen; Protein Isoforms; Proto-Oncogene Proteins p21(ras); Pyridines; Receptors, Cell Surface; Receptors, Urokinase Plasminogen Activator

Topics: Aniline Compounds; Bradykinin; Drug Approval; Drug Design; Drug Evaluation; Humans; Molecular Structure; Piperidines; Propionates; Pyridines; Time Factors

Farnesyl transferase (FT) inhibitors (FTI) are anticancer agents developed to target oncogenic Ras proteins by inhibiting Ras farnesylation. FTIs potently synergize with paclitaxel and other microtubule-stabilizing drugs; however, the mechanistic basis underlying this synergistic interaction remains elusive. Here we show that the FTI lonafarnib affects the microtubule cytoskeleton resulting in microtubule bundle formation, increased microtubule stabilization and acetylation, and suppression of microtubule dynamics. Notably, treatment with the combination of low doses of lonafarnib with paclitaxel markedly enhanced tubulin acetylation (a marker of microtubule stability) as compared with either drug alone. This synergistic effect correlated with FT inhibition and was accompanied by a synergistic increase in mitotic arrest and cell death. Mechanistically, we show that the combination of lonafarnib and paclitaxel inhibits the in vitro deacetylating activity of the only known tubulin deacetylase, histone deacetylase 6 (HDAC6). In addition, the lonafarnib/taxane combination is synergistic only in cells lines expressing the wild-type HDAC6, but not a catalytic-mutant HDAC6, revealing that functional HDAC6 is required for the synergy of lonafarnib with taxanes. Furthermore, tubacin, a specific HDAC6 inhibitor, synergistically enhanced tubulin acetylation in combination with paclitaxel, similar to the combination of lonafarnib and paclitaxel. Taken together, these data suggest a relationship between FT inhibition, HDAC6 function, and cell death, providing insight into the putative molecular basis of the lonafarnib/taxane synergistic antiproliferative combination.

Topics: Acetylation; Alkyl and Aryl Transferases; Animals; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Carcinoma, Non-Small-Cell Lung; Cell Death; Cell Line, Tumor; Drug Synergism; Farnesyltranstransferase; Histone Deacetylase 6; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Lung Neoplasms; Mice; Microtubules; Mitosis; NIH 3T3 Cells; Paclitaxel; Piperidines; Pyridines; Tubulin

Recent studies indicate that a rare population of primitive quiescent BCR-ABL(+) cells are innately insensitive to imatinib mesylate (IM) and persist after IM therapy of patients with chronic myeloid leukemia (CML). New approaches to the eradication of these cells are therefore likely to be crucial to the development of curative therapies for CML. We have now found that Ara-C, LY294002 (a PI-3 (phosphatidylinositol-3' kinase) kinase inhibitor), 17AAG (a heat-shock protein (HSP)-90 antagonist) and lonafarnib (a farnesyltransfease inhibitor) all enhance the toxicity of IM on K562 cells and on the total CD34(+) leukemic cell population from chronic phase CML patients. However, for quiescent CD34(+) leukemic cells, this was achieved only by concomitant exposure of the cells to lonafarnib. Ara-C or LY294002 alone blocked the proliferation of these cells but did not kill them, and Ara-C, LY294002 or 17AAG in combination with IM enhanced the cytostatic effect of IM but did not prevent the subsequent regrowth of the surviving leukemic cells. These studies demonstrate the importance of in vitro testing of novel agents on the subset of primary leukemic cells most likely to determine long-term treatment outcomes in vivo.

Topics: Antigens, CD34; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Benzoquinones; Cell Line, Tumor; Cell Proliferation; Chromones; Cytarabine; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Drug Synergism; Female; Humans; Imatinib Mesylate; Lactams, Macrocyclic; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Male; Morpholines; Piperazines; Piperidines; Pyridines; Pyrimidines; Rifabutin

Farnesyl protein transferase inhibitors (FTIs) have demonstrated clinical activity in certain solid tumors and hematological malignancies. Little is known about mechanisms of resistance to these agents. To provide a basis for better understanding FTI resistance, the colorectal carcinoma cell line HCT 116 was selected by stepwise exposure to increasing 4-(2-(4-(8-chloro-3,10-dibromo-6,11-dihydro-5H-benzo-(5,6)-cyclohepta(1,2-b)-pyridin-11(R)-yl)-1-piperidinyl)-2-oxo-ethyl)-1-piperidinecarboxamide (SCH66336) concentrations. The resulting line, HCT 116R, was 100-fold resistant to SCH66336 and other FTIs, including methyl {N-[2-phenyl-4-N[2(R)-amino-3-mercaptopropylamino] benzoyl]}-methionate (FTI-277), but was less than 2-fold resistant to the standard agents gemcitabine, cisplatin, and paclitaxel. Accumulation of the unfarnesylated forms of prelamin A and HDJ-2, two substrates that reflect farnesyl transferase inhibition, was similar in FTI-treated parental and HCT 116R cells, indicating that alterations in drug uptake or inhibition of farnesyl protein transferase is not the mechanism of resistance. Changes in signal-transduction pathways that might account for this resistance were examined by immunoblotting and confirmed pharmacologically. There was no difference in activation of the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase pathway or sensitivity to the MEK1/2 inhibitor 2'-amino-3'-methoxyflavone (PD98059) in HCT 116R cells. In contrast, increased phosphorylation of the molecular target of rapamycin (mTOR) and its downstream target p70 S6 kinase and increased levels of Akt1 and Akt2 were demonstrated in HCT 116R cells. Further experiments demonstrated that the mTOR inhibitor rapamycin selectively sensitized HCT 116R cells to SCH66336 but not to gemcitabine, cisplatin, or paclitaxel. These findings provide evidence that alterations in the phosphatidylinositol-3 kinase/Akt pathway can contribute to FTI resistance and suggest a potential strategy for overcoming this resistance.

Topics: Alkyl and Aryl Transferases; Carcinoma; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Enzyme Inhibitors; Farnesyltranstransferase; HCT116 Cells; Humans; Piperidines; Pyridines

Farnesyltransferase inhibitors (FTI) are a class of therapeutic agents designed to target tumors with mutations of the ras oncogene. However, the biological effect of FTIs is often independent of ras mutation status, which suggests the existence of additional mechanisms. In this study, we investigated the molecular effects of SCH66336, an FTI, in head and neck squamous cell carcinoma cells using proteomic approaches. We showed that SCH66336 induced phosphorylation (inactivation) of eukaryotic translation elongation factor 2 (eEF2), an important molecule for protein synthesis, as early as 3 hours after SCH66336 administration. Protein synthesis was subsequently reduced in the cells. Paradoxically, activation of eEF2 kinase (eEF2K), the only known kinase that regulates eEF2, was observed only at 12 hours after SCH66336 treatment. Consistent with this observation, the inhibition of phosphorylated-MEK and phosphorylated-p70S6K, the two key signaling molecules responsible for activation of eEF2K, also occurred at least 12 hours after SCH66336 administration. Our data suggest that inhibition of protein synthesis through inactivation of eEF2 is a novel mechanism of SCH66336-mediated growth inhibition and that this effect is independent of ras-MEK/p70S6K-eEF2K signaling cascades.

Topics: Alkyl and Aryl Transferases; Amino Acid Sequence; Carcinoma, Squamous Cell; Cell Cycle; Cell Growth Processes; Cell Line, Tumor; Farnesyltranstransferase; Head and Neck Neoplasms; Humans; MAP Kinase Signaling System; Molecular Sequence Data; Neoplasm Proteins; Peptide Elongation Factor 2; Phosphorylation; Piperidines; Protein Synthesis Inhibitors; Pyridines

Lonafarnib is a novel anticancer drug that inhibits farnesyl transferase. To assess its pharmacokinetic properties, we developed a sensitive and quantitative assay using liquid chromatography coupled with tandem mass spectrometry for the determination of lonafarnib levels in human plasma. Sample pretreatment consisted of the addition of an isotopically labeled internal standard and protein precipitation with acetonitrile using 100 microL plasma. Chromatographic separation was performed on an Inertsil ODS-3 analytical column (50 x 2.1 mm i.d., particle size 5 microm) with acetonitrile/water/formic acid (50:50:0.05, v/v/v) as the mobile phase, at a flow rate of 0.2 mL/min. The analytical run time was 8 min. An API365 triple quadrupole mass spectrometer was used for specific and sensitive detection. It was operated in the positive ion mode and multiple reaction monitoring was used for drug quantification. The method was validated using a concentration range of 2.5 to 2500 ng/mL lonafarnib. Validation of the assay was performed according to the most recent FDA guidelines for bioanalytical method validation and all results were within the requirements. The described method was successfully applied to support a clinical phase I trial with lonafarnib.

Topics: Administration, Oral; Alkyl and Aryl Transferases; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Chromatography, High Pressure Liquid; Clinical Trials, Phase I as Topic; Drug Therapy, Combination; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Injections, Intravenous; Molecular Structure; Paclitaxel; Piperidines; Pyridines; Reproducibility of Results; Spectrometry, Mass, Electrospray Ionization; Trastuzumab

Lonafarnib (SCH66336) is a farnesyl transferase inhibitor (FTI) that inhibits the post-translational lipid modification of H-Ras and other farnesylated proteins. K- and N-Ras are also substrates of farnesyl transferase; however, upon treatment with FTIs, they are alternatively prenylated by geranylgeranyl transferase-1. Despite the failure to abrogate prenylation of K- and N-Ras, growth of many tumors in preclinical models is inhibited by FTIs. This suggests that the anti-proliferative action of FTIs is dependent on blocking the farnesylation of other proteins. Rheb (Ras homologue enriched in brain) is a farnesylated small GTPase that positively regulates mTOR (mammalian target of rapamycin) signaling. We found that Rheb and Rheb2 mRNA were elevated in various tumor cell lines relative to normal cells. Peptides derived from the carboxyl termini of human Rheb and Rheb2 are in vitro substrates for farnesyl transferase but not geranylgeranyl transferase-1. Rheb prenylation in cell culture was completely inhibited by SCH66336, indicating a lack of alternative prenylation. SCH66336 treatment also inhibited the phosphorylation of S6 ribosomal protein, a downstream target of Rheb and mTOR signaling. SCH66336 did not inhibit S6 phosphorylation in cells expressing Rheb-CSVL, a mutant construct of Rheb designed to be geranylgeranylated. Importantly, expression of Rheb-CSVL also abrogated SCH66336 enhancement of tamoxifen- and docetaxel-induced apoptosis in MCF-7 breast cancer cells and ES-2 ovarian cancer cells, respectively. Further, inhibition of Rheb signaling by rapamycin treatment, small interfering RNA, or dominant negative Rheb enhanced tamoxifen- and docetaxel-induced apoptosis, similar to FTI treatment. These studies demonstrated that Rheb is modified by farnesylation, is not a substrate for alternative prenylation, and plays a role in SCH66336 enhancement of the anti-tumor response to other chemotherapeutics.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Bridged-Ring Compounds; Caspases; Cell Line, Tumor; Farnesyltranstransferase; Humans; Monomeric GTP-Binding Proteins; Neoplasms; Neuropeptides; Phosphorylation; Piperidines; Protein Kinases; Protein Prenylation; Pyridines; Ras Homolog Enriched in Brain Protein; Recombinant Fusion Proteins; RNA, Messenger; Signal Transduction; Tamoxifen; Taxoids; TOR Serine-Threonine Kinases

The identification of signaling pathways critical to myeloma growth and progression has yielded an array of novel agents with clinical activity. Multiple myeloma (MM) growth is IL-6 dependent, and IL-6 is secreted in an autocrine/paracrine fashion with signaling via the Ras/Raf/mitogen-activated protein kinase (MAPK) pathway. We hypothesized that combining a Ras pathway inhibitor (lonafarnib, SCH66336) with a proteasome inhibitor (bortezomib, Velcade, PS-341) would enhance myeloma-cell killing. MM cell lines and primary human cells were used to test either single agent bortezomib, lonafarnib, or the combination on MM signaling and apoptosis. Combination therapy induced synergistic tumor-cell death in MM cell lines and primary MM plasma cells. Cell death was rapid and associated with increased caspase 3, 8, and 9 cleavage and concomitant down-regulation of p-AKT. Down-regulation of p-AKT was seen only in combination therapy and not seen with either single agent. Cells transfected with constitutively active p-AKT, wild-type AKT, or Bcl-2 continued to demonstrate synergistic cell death in response to the combination. The order of addition was critically important, supporting bortezomib followed by lonafarnib as the optimal schedule. The combination of a proteasome inhibitor and farnesyl transferase inhibitor demonstrates synergistic myeloma-cell death and warrants further preclinical and clinical studies.

Topics: Apoptosis; Boronic Acids; Bortezomib; Down-Regulation; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Insulin-Like Growth Factor I; Interleukin-6; Multiple Myeloma; Phosphorylation; Piperidines; Proteasome Inhibitors; Proto-Oncogene Proteins c-akt; Pyrazines; Pyridines; Time Factors; Tumor Cells, Cultured

The farnesyltransferase inhibitor SCH66336, in combination with other receptor tyrosine kinase inhibitors, inhibits the growth of non-small-cell lung cancer (NSCLC) cells. We examined whether SCH66336 inhibits angiogenesis of aerodigestive tract cancer cells.. Antiangiogenic activities of SCH66336 against NSCLC, head and neck squamous cell carcinoma (HNSCC), and endothelial cells were examined with cell proliferation, capillary tube formation, and chick aorta (under hypoxic, normoxic, insulin-like growth factor I (IGF)-stimulated, and unstimulated conditions); reverse transcription-polymerase chain reaction; and western blot analyses. The specific roles of the ubiquitin-mediated proteasome machinery, mitogen-activated protein kinase (MAPK) and Akt pathways, and heat shock protein 90 (Hsp90) in the SCH66336-mediated degradation of hypoxia-inducible factor 1alpha (HIF-1alpha) were assessed with ubiquitin inhibitors and adenoviral vectors that express constitutively active MAP kinase kinase (MEK)1, constitutively active Akt, or Hsp90.. SCH66336 showed antiangiogenic activities and decreased the expression of vascular endothelial cell growth factor (VEGF) and HIF-1alpha in hypoxic, IGF-stimulated, and unstimulated aerodigestive tract cancer and endothelial cells. SCH66336 reduced the half-life of the HIF-1alpha protein, and ubiquitin inhibitors protected the hypoxia- or IGF-stimulated HIF-1alpha protein from SCH66336-mediated degradation. SCH66336 inhibited the interaction between HIF-1alpha and Hsp90. The overexpression of Hsp90, but not constitutive Akt or constitutive MEK, restored HIF-1alpha expression in IGF-stimulated or hypoxic cells but not in unstimulated cells.. SCH66336 appears to inhibit angiogenic activities of NSCLC and HNSCC cells by decreasing hypoxia- or IGF-stimulated HIF-1alpha expression and to inhibit VEGF production by inhibiting the interaction between HIF-1alpha and Hsp90, resulting in the proteasomal degradation of HIF-1alpha.

Topics: Alkyl and Aryl Transferases; Angiogenesis Inhibitors; Animals; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Carcinoma, Squamous Cell; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Enzyme Inhibitors; Farnesyltranstransferase; Female; Gene Expression Regulation, Neoplastic; Head and Neck Neoplasms; HSP90 Heat-Shock Proteins; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Immunohistochemistry; Immunoprecipitation; Lung Neoplasms; Mice; Mice, Nude; Mitogen-Activated Protein Kinase Kinases; Neovascularization, Pathologic; Phosphatidylinositol 3-Kinases; Piperidines; Proteasome Endopeptidase Complex; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Pyridines; Reverse Transcriptase Polymerase Chain Reaction; Transcription Factors; Ubiquitin; Up-Regulation; Vascular Endothelial Growth Factor A

Treatment of chronic myelogenous leukemia with a specific inhibitor of the Bcr/Abl tyrosine kinase, imatinib, has shown great promise. However, acute lymphoblastic leukemias that express Bcr/Abl only transiently respond to imatinib. Therefore, alternative treatments for this type of leukemia are urgently needed. Here, we examined the activity of the farnesyltransferase inhibitor SCH66336 as a single chemotherapeutic agent in a nude mouse model representative of very advanced stage Bcr/Abl P190-positive lymphoblastic leukemia/lymphoma. Our results show that oral administration of the inhibitor was able to significantly increase the survival of these mice compared to controls treated with vehicle (P<0.005), and caused marked regression of the tumor burden in the treated mice. Upon prolonged treatment, lymphomas re-emerged and a subset of cells from two of such lymphomas tested was able to survive in the presence of increased concentrations of SCH66336. The same cells, however, remained sensitive towards imatinib. A combination of the two drugs, preceded by a therapy to reduce the initial tumor burden, could be very effective in the treatment of Ph-positive ALL. We conclude that SCH66336, on its own, is remarkably effective in eradicating large numbers of lymphoblastic lymphoma cells and causing visible reduction in tumor size, with minimal toxicity.

Topics: Administration, Oral; Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Benzamides; Disease Models, Animal; Farnesyltranstransferase; Female; Fusion Proteins, bcr-abl; Imatinib Mesylate; Leukemia, Experimental; Lymphoma; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Nude; Mice, Transgenic; Piperazines; Piperidines; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Protein-Tyrosine Kinases; Pyridines; Pyrimidines; Survival Rate; Tumor Cells, Cultured

K-ras alterations have been reported in 20-30% of non-small cell lung cancer (NSCLC) and represent a suitable target for the development of novel anticancer agents, such as Farnesyl transferase inhibitors (FTi), a new class of agents inhibiting the post-translational modification of the K-ras proteins. The effectiveness of FTi SCH66336 in inhibiting cell proliferation and deranging cell cycle of NSCLC cell lines as well as its interaction with chemotherapy or radiation have been evaluated. The activity of FTi SCH66336, alone or in combination with paclitaxel, gemcitabine, and radiotherapy, was examined in 3 cell lines, A-549, LX-1 and CaLu-6, by colorimetric MTT assay. Cell cycle perturbation and apoptosis were also assessed by cytofluorimetric analysis. The activity of SCH 66336 was found to be concentration- and time-dependent. The effect of SCH 66336, as demonstrated by cell growth recovery experiments, resulted cytostatic and it was superimposable in both cell lines bearing 2 different K-ras mutations (A-549 and LX-1) and in K-ras wild-type Ca-Lu-6. In all cell lines the combination of SCH 66336 and paclitaxel resulted in a synergism of action when SCH 66336 followed paclitaxel treatment, whereas, antagonism was found when SCH 66336 preceded paclitaxel treatment. No significant synergism or addition with SCH 66336 followed by radiation treatment was noted. Different cell cycle phase blocks at various drug concentrations were observed. In conclusion, SCH 66336 displays concentration-dependent cytostatic antitumour activity and schedule-dependent synergy with 2 commonly used anticancer agents in NSCLC cell lines. Further clinical testing of these combinations is warranted.

Topics: Alkyl and Aryl Transferases; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Combined Modality Therapy; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Lung Neoplasms; Piperidines; Pyridines

Ras farnesyltransferase inhibitor (FTI) exhibit antiproliferative and antiangiogenic effects through a mechanism that is poorly understood. Because of the known role of Ras in the activation of transcription factor NF-kappaB and because NF-kappaB-regulated genes can control cell survival and angiogenesis, we postulated that FTI mediates its effects in part by modulating NF-kappaB activation. Therefore, in the present study we investigated the effect of FTI, SCH 66336, on NF-kappaB and NF-kappaB-regulated gene expression activated by a variety of inflammatory and carcinogenic agents. We demonstrate by DNA-binding assay that NF-kappaB activation induced by tumor necrosis factor (TNF), phorbol 12-myristate 13-acetate, cigarette smoke, okadaic acid, and H(2)O(2) was completely suppressed by SCH 66336; the suppression was not cell type-specific. This FTI suppressed the activation of IkappaBalpha kinase (IKK), thus abrogating the phosphorylation and degradation of IkappaBalpha. Additionally, TNF-activated Ras and SCH 66336 inhibited the activation. Also, overexpression of Ras (V12) enhanced TNF-induced NF-kappaB activation, and adenoviral dominant-negative Ras (N17) suppressed the activation, thus suggesting the critical role of Ras in TNF signaling. SCH 66336 also inhibited the NF-kappaB-dependent reporter gene expression activated by TNF, TNFR1, TRADD, TRAF2, NIK, and IKK but not that activated by the p65 subunit of NF-kappaB. The TNF-induced NF-kappaB-regulated gene products cyclin D1, COX-2, MMP-9, survivin, IAP1, IAP2, XIAP, Bcl-2, Bfl-1/A1, TRAF1, and FLIP were all down-regulated by SCH 66336, which potentiated apoptosis induced by TNF and doxorubicin. Overall, our results indicate that SCH 66336 inhibited activation of NF-kappaB and NF-kappaB-regulated gene expressions induced by carcinogens and inflammatory stimuli, which may provide a molecular basis for the ability of SCH 66336 to suppress proliferation and angiogenesis.

Topics: Active Transport, Cell Nucleus; Alkyl and Aryl Transferases; Apoptosis; Blotting, Western; Carcinogens; Cell Division; Cell Line, Tumor; Cell Survival; Cytoplasm; DNA; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Humans; Hydrogen Peroxide; I-kappa B Kinase; Immunohistochemistry; In Situ Nick-End Labeling; Inflammation; Jurkat Cells; Models, Chemical; Neovascularization, Pathologic; NF-kappa B; Okadaic Acid; Phosphorylation; Piperidines; Protein Binding; Protein Serine-Threonine Kinases; Pyridines; ras Proteins; Smoking; Time Factors; Tumor Necrosis Factor-alpha; Up-Regulation

A solution phase parallel synthesis approach was undertaken to rapidly explore the structure-activity relationship of an inhibitor of the Ras/Raf protein interaction identified from a small molecule compound library. Evaluation of the MAPK pathway signaling inhibitory activity of the synthesized analogues as well as their antiproliferative activity and ability to inhibit soft agar growth were performed.

Topics: Animals; Cell Division; Cell Line; CHO Cells; Cricetinae; Drug Design; Enzyme Inhibitors; Kinetics; Mitogen-Activated Protein Kinases; Molecular Structure; Piperidines; Pyridines; ras Proteins; Recombinant Proteins; Signal Transduction; Structure-Activity Relationship

Farnesyltransferase inhibitors (FTIs) have been demonstrated to induce growth arrest or apoptosis independent of Ras mutation. Alternatively, Akt has been proposed as a potential target for the FTI's actions. This study investigated whether Lonafarnib was effective in inhibiting the growth of human nonsmall cell lung cancer (NSCLC) cells and elucidated the role of Akt in mediating such growth inhibitory effects. Lonafarnib, at clinical achievable concentration ranges, was effective in inhibiting the growth of 10 NSCLC cell lines, particularly after a prolonged treatment, regardless of Ras mutational status. Lonafarnib arrested cells growth at G(1) or G(2)/M phase in the majority tested cell lines. However it induced apoptosis when cells were cultured in a low serum (0.1%) medium. The majority of NSCLC cell lines expressed undetectable level of phosphorylated Akt (p-Akt). Lonafarnib at up to 10 muM did not decrease either total Akt level or p-Akt level in any of the tested cell lines, even after a 48 h treatment. Unexpectedly, Lonafarnib even increased p-Akt level in one cell line, although it was as sensitive as others to Lonafarnib treatment and underwent G(2)/M arrest. Bovine serum albumin completely rescued cells from Lonafarnib-induced apoptosis in low serum medium, indicating that proteins rather than cytokines or growth factors in serum masks Lonafarnib's pro-apoptotic effect. Therefore, we conclude that Lonafarnib is effective in inhibiting the growth of NSCLC cells either via growth arrest or induction of apoptosis without downregulation of Akt.

Topics: Alkyl and Aryl Transferases; Animals; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cattle; Cell Cycle; Down-Regulation; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Lung Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Piperidines; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Pyridines; Serum Albumin, Bovine; Signal Transduction; Tumor Cells, Cultured

Overexpression of insulin-like growth factor binding protein-3 (IGFBP-3) induces apoptosis in non-small-cell lung cancer (NSCLC) cells in vitro and in vivo. However, Ras-mediated signaling pathways could develop resistance to apoptotic activities of IGFBP-3 in NSCLC cells. We thus evaluated the therapeutic potential of the combination of IGFBP-3 and SCH66336, a farnesyltransferase inhibitor that blocks Ras activation, in NSCLC cell lines.. The effects of the combination of adenoviral IGFBP-3 (Ad-IGFBP3) and SCH66336 on proliferation and apoptosis of NSCLC cell lines (H1299, H596, A549, H460, H358, H322, and H226B) were assessed in vitro and in vivo by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a flow cytometry-based terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling assay, western blot analyses, and an NSCLC xenograft tumor model. The specific effects of Ad-IGFBP 3 and SCH66336 on mitogen-activated protein kinase and Akt were assessed by using adenoviral vectors that express constitutively active MEK1 or constitutively active Akt. Synergy was assessed by median effect analysis.. The combination of Ad-IGFBP3 and SCH66336 had synergistic antiproliferative effects in five cell lines (H1299, H596, A549, H460, and H322). Antiproliferative effects were accompanied by increased apoptosis in H460 cells in vitro. Overexpression of a constitutively active Akt but not a constitutively active MEK-1 rescued H460 cells from apoptosis induced by single or combined treatment of Ad-IGFBP3 and SCH66336. In H1299 tumor xenografts, Ad-IGFBP3 and SCH66336 was associated with decreased tumor volume, increased apoptosis, and decreased Akt levels.. The combination of Ad-IGFBP3 and SCH66336 decreased Akt expression and increased apoptosis in NSCLC cells in vitro and in vivo. Simultaneous treatment with IGFBP-3 and SCH66336 may have the potential to be an effective therapeutic strategy in NSCLC.

Topics: Adenoviridae; Alkyl and Aryl Transferases; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Drug Synergism; Enzyme Inhibitors; Farnesyltranstransferase; Flow Cytometry; Gene Expression Regulation, Neoplastic; Gene Products, tat; Genes, ras; Genetic Vectors; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Insulin-Like Growth Factor Binding Protein 3; Lung Neoplasms; MAP Kinase Kinase 1; Mice; Mice, Nude; Mitogen-Activated Protein Kinase Kinases; Piperidines; Precipitin Tests; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Pyridines; ras Proteins; Transplantation, Heterologous; Tumor Cells, Cultured

Topics: Alkyl and Aryl Transferases; Apoptosis; Cell Cycle; Down-Regulation; Enzyme Inhibitors; Farnesyltranstransferase; Humans; Lung Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Piperidines; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Pyridines; Signal Transduction

SCH 66336 is a trihalo tricyclic compound that is currently undergoing Phase II clinical trials for the treatment of solid tumors. Modifications of SCH 66336 by incorporating such groups as amides, acids, esters, ureas and lactams off the first or the distal piperidine (from the tricycle) provided potent FPT inhibitors some of which exhibited good cellular activity. A number of these compounds incorporate properties that might improve pharmacokinetic stability of these inhibitors by virtue of their increased solubility or by their change in log P.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; COS Cells; Enzyme Inhibitors; Kidney; Models, Molecular; Piperidines; Pyridines; Solubility; Structure-Activity Relationship; Tritium

Topics: Alkyl and Aryl Transferases; Apoptosis; Benzamides; Drug Synergism; Enzyme Inhibitors; Farnesyltranstransferase; Fusion Proteins, bcr-abl; Humans; Imatinib Mesylate; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Neoplasm Proteins; Piperazines; Piperidines; Pyridines; Pyrimidines; Research Design; Tumor Cells, Cultured

BCR-ABL fusion proteins exhibit elevated tyrosine kinase activity and transforming properties. Genetic and biochemical data suggest that Ras activation plays a central role in leukemogenic transformation by BCR-ABL. Imatinib (Novartis, Basel, Switzerland) is a potent and selective inhibitor of the tyrosine kinase activity of BCR-ABL. Although imatinib has shown promise against Ph-positive leukemia in human clinical trials, the emergence of imatinib resistance in patients with acute forms of Ph-positive leukemia has highlighted the need for combination chemotherapy to eradicate this disease. In the present study, combined use of a farnesyl transferase inhibitor, SCH66336 (lonafarnib), with the antileukemic agents imatinib, daunorubicin, cytosine arabinoside, or etoposide was investigated by cell proliferation assays. The effects of the combination of SCH66336 and imatinib were also investigated by apoptosis assay and colony-forming assay. In proliferation assays with BCR-ABL-expressing cells, combination of SCH66336 with imatinib or cytosine arabinoside showed enhanced antiproliferative activity, whereas combination of SCH66336 with daunorubicin or etoposide demonstrated an antagonistic effect. The combination of imatinib plus SCH66336 more effectively inhibited hematopoietic colony formation by primary human chronic myelogenous leukemia cells. SCH66336 combined with imatinib was shown to induce apoptosis in imatinib-resistant BCR-ABL cells by flow cytometric analysis with an APO2.7 monoclonal antibody. These results indicate that SCH66336 is a promising candidate for use in the treatment of patients with imatinib-resistant, Ph-positive leukemia and that the combination of SCH66336 plus imatinib may be useful to circumvent resistance.

Topics: Alkyl and Aryl Transferases; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzamides; Cell Division; Colony-Forming Units Assay; Cytarabine; Daunorubicin; Drug Resistance, Neoplasm; Enzyme Inhibitors; Etoposide; Farnesyltranstransferase; Fusion Proteins, bcr-abl; Humans; Imatinib Mesylate; Interleukin-3; Leukemia, Myeloid, Acute; Piperazines; Piperidines; Protein-Tyrosine Kinases; Pyridines; Pyrimidines; Transfection; Treatment Outcome; Tumor Cells, Cultured

Topics: Alkyl and Aryl Transferases; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Benzamides; Cell Division; Drug Resistance, Neoplasm; Enzyme Inhibitors; Farnesyltranstransferase; Fusion Proteins, bcr-abl; Humans; Imatinib Mesylate; Leukemia, Myeloid, Acute; Piperazines; Piperidines; Pyridines; Pyrimidines

The constitutive activity of a number of growth and cell survival pathways are thought to contribute to the inherent resistance of melanoma to chemotherapy and radiotherapy. Many of these pathways are driven through the small GTPase Ras. Novel drugs such as the farnesyl transferase inhibitors (FTIs) and farnesyl thiosalicylic acid (FTS) interfere with the signaling of oncogenic Ras. The aim of our study was to assess the anti-tumour activity of the FTI SCH66336 in melanoma and to assess whether SCH66336 and FTS could modulate chemoresistance in melanoma cells. SCH66336 had marked anti-proliferative activity in both human and mouse melanoma cell lines, but not in non-transformed NIH 3T3 cells. The anti-proliferative activity of SCH66336 was due to G1-phase cell cycle arrest and retinoblastoma protein inactivation, followed by apoptosis. Cisplatin, when administered alone, induced little apoptosis. In combination with cisplatin, both FTS and SCH66336 markedly enhanced the level of cisplatin-induced apoptosis, an effect that was associated with enhanced G2/M cell cycle arrest. Pharmacological inhibitors of either ERK or PI-3 kinase/Akt did not mimic the chemosensitising activity of either SCH66336 or FTS. In summary, our study demonstrates that SCH66336 has good in vitro anti-tumour activity in both human and mouse melanoma cell lines, and suggests that Ras antagonists could be useful in overcoming chemoresistance to cisplatin in melanoma.

Topics: 3T3 Cells; Actins; Alkyl and Aryl Transferases; Animals; Apoptosis; Blotting, Western; Cell Cycle; Cell Division; Cisplatin; Colony-Forming Units Assay; Drug Synergism; Enzyme Inhibitors; Farnesol; Farnesyltranstransferase; Humans; In Situ Nick-End Labeling; In Vitro Techniques; Melanoma; Mice; Microscopy, Confocal; Mitogen-Activated Protein Kinases; Piperidines; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Pyridines; Retinoblastoma Protein; Salicylates; Skin Neoplasms; Tumor Cells, Cultured

A novel enantioselective alkylation of double benzylic substrates with secondary electrophiles is reported. A simple norephedrine-based chiral ligand was synthesized that gives alkylation product in 95% yield and 95% ee. A unique water effect on the enantioselectivity was unveiled. Good to excellent ee values were obtained with a number of double benzylic substrates and secondary electrophiles. This novel reaction has been applied to the synthesis of a promising anticancer agent.

Topics: Alkylation; Antineoplastic Agents; Catalysis; Combinatorial Chemistry Techniques; Indicators and Reagents; Molecular Structure; Piperidines; Pyridines; Stereoisomerism

The farnesyltransferase inhibitor SCH66336 exhibits antitumor activity in vitro and in vivo; however, its mechanism of action is still unresolved. We found that SCH66336 suppressed growth and induced apoptosis of human head and neck squamous carcinoma cells (HNSCC). SCH66336 suppressed protein kinase B/Akt activity as well as the phosphorylation of the Akt substrates glycogen synthase kinase (GSK)-3 beta, forkhead transcription factor, and BAD. Infection of SqCC/Y1 cells with an adenovirus that contained a constitutively active form of Akt rescued cells from SCH66336-induced apoptosis. These results suggest that SCH66336 is a potent apoptosis inducer in HNSCC cells and that it may act by suppressing the Akt pathway.

Topics: Alkyl and Aryl Transferases; Apoptosis; bcl-X Protein; Carcinoma, Squamous Cell; Enzyme Inhibitors; Farnesyltranstransferase; Head and Neck Neoplasms; Humans; Piperidines; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Pyridines; Tumor Cells, Cultured

A generic high-performance liquid chromatography (HPLC) system interfaced with an atmospheric pressure photoionization (APPI) source and a tandem mass spectrometer was developed for the quantitative determination of small molecules in plasma in support of exploratory in vivo pharmacokinetics. This report summarizes the effects of variations in reversed-phase mode HPLC conditions such as mobile-phase flow rate, solvent composition, organic modifier content, and nebulizer temperature on the photoionization efficiency of both clozapine and lonafarnib. The matrix ionization suppression effect on this method was investigated using the postcolumn infusion technique. The procedure was used to quantitate plasma levels following oral administration of 42 drug discovery compounds to rats. The pharmacokinetic results of 42 drug discovery compounds in rats evaluated by both APPI and atmospheric pressure chemical ionization interfaces were found to be well correlated.

Topics: Administration, Oral; Animals; Atmospheric Pressure; Chromatography, High Pressure Liquid; Clozapine; Drug Evaluation, Preclinical; Drugs, Investigational; Mass Spectrometry; Photochemistry; Piperidines; Pyridines; Rats

Farnesyltransferase inhibitors were initially developed as Ras inhibitors as they inhibit the prenylation necessary for Ras activation. It is clear now that their mechanism of action is more complex and probably involves other proteins unrelated to Ras. At least 3 drugs within this family have been investigated in acute myeloid leukemia, myelodysplastic syndromes, and other leukemias. These are tipifarnib (R115777, Zarnestra), lonafarnib (SCH66336, Sarasar), and BMS-214662. The first 2 are administered orally, whereas BMS-214662 is given intravenously. These drugs are at different stages of development, and design of treatment schedules and methodology of the available studies are very different. Although most of the information is still preliminary, these agents have demonstrated clear evidence of clinical activity in these diseases and very favorable toxicity profiles. Several studies are still ongoing to better define the efficacy of these agents in the treatment of leukemias, as well as to determine the best schedules, the role of combination with other agents, and the role of these agents in different settings, such as the management of minimal residual disease. It is very possible that these agents will soon find their way to the ranks of established agents for the management of myeloid malignancies

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Benzodiazepines; Clinical Trials as Topic; Farnesyltranstransferase; Humans; Imidazoles; Leukemia, Myeloid, Acute; Myelodysplastic Syndromes; Piperidines; Pyridines; Quinolones

Clinical studies indicate that the farnesyl protein transferase inhibitor SCH66336 (lonafarnib), an anticancer agent developed to antagonize oncogenic Ras, is generally well tolerated. Lonafarnib has also demonstrated therapeutic synergy with coadministered taxanes, vincristine, cisplatin, cyclophosphamide, 5-fluorouracil (5-FU) and Gleevec. Lonafarnib has recently been shown, in addition, to be a potent inhibitor of the transmembrane efflux transporter P-glycoprotein (P-gp), which confers cellular resistance to the substrates vincristine, taxol and paclitaxel. Treatment with lonafarnib would therefore be predicted to be synergistic with these coadministered cancer therapeutics that are substrates of P-gp. However, cisplatin, 5-FU and cyclophosphamide are not P-gp substrates, yet cisplatin, 5-FU and possibly cyclophosphamide are purported substrates for multidrug resistance proteins (MRPs) 1 and 2 (known to cause chemotherapy resistance). Lonafarnib is shown here to inhibit the function of MRP1 and MRP2 with a potency similar to that of cyclosporin A and may therefore cause the observed synergy with cisplatin and other agents by inhibiting these MRPs. Coadministration of lonafarnib could thus reduce chemotherapy dosage and hence produce lower exposure to normal cells and less undesired toxicity.

Topics: Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cell Line; Cisplatin; Cyclophosphamide; Drug Interactions; Drug Resistance, Multiple; Flow Cytometry; Fluorouracil; Humans; Piperidines; Pyridines

The development of chronic myeloid leukemia (CML) is dependent on the deregulated tyrosine kinase of the oncoprotein BCR-ABL. STI571 (imatinib mesylate), an abl tyrosine kinase inhibitor, has proven remarkably effective for the treatment of CML. However, resistance to STI571 because of enhanced expression or mutation of the BCR-ABL gene has been detected in patients. In the current study we show that the farnesyl transferase inhibitor (FTI) SCH66336 (lonafarnib) inhibits the proliferation of STI571-resistant BCR-ABL-positive cell lines and hematopoietic colony formation from peripheral blood samples of STI571-resistant patients with CML. Moreover, SCH66336 enhances STI571-induced apoptosis in STI571-sensitive cells and, in patients with STI571 resistance from gene amplification, cooperates with STI571 to induce apoptosis. Our data provide a rationale for combination clinical trials of STI571 and SCH66336 in CML patients and suggest that combination therapy may be effective in patients with STI571 resistance.

Topics: Alkyl and Aryl Transferases; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Cell Survival; Drug Resistance, Neoplasm; Enzyme Inhibitors; Farnesyltranstransferase; Hematopoietic Stem Cells; Humans; Imatinib Mesylate; K562 Cells; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Piperazines; Piperidines; Pyridines; Pyrimidines

The 10-bromobenzocycloheptapyridyl farnesyl transferase inhibitor (FTI) Sch-66336 (1) is currently under clinical evaluation for the treatment of human cancers. During structure-activity relationship development leading to 1, 10-bromobenzocycloheptapyridyl FTIs were found to be more potent than analogous compounds lacking the 10-Br substituent. This potency enhancement was believed to be due, in part, to an increase in conformational rigidity as the 10-bromo substituent could restrict the conformation of the appended C(11) piperidyl substituent in an axial orientation. A novel and potent class of FTIs, represented by indolocycloheptapyridine Sch-207758 [(+)-10a], have been designed based on this principle. Although structural and thermodynamic results suggest that entropy plays a crucial role in the increased potency observed with (+)-10a through conformational constraints and solvation effects, the results also indicate that the indolocycloheptapyridine moiety in (+)-10a provides increased hydrophobic interactions with the protein through the addition of the indole group. This report details the X-ray structure and the thermodynamic and pharmacokinetic profiles of (+)-10a, as well as the synthesis of indolocycloheptapyridine FTIs and their potencies in biochemical and biological assays.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Bromine; Crystallography, X-Ray; Enzyme Inhibitors; Half-Life; Indoles; Mice; Mice, Nude; Models, Molecular; Piperidines; Pyridines; Structure-Activity Relationship; Thermodynamics

An international meeting focused on farnesyl transferase inhibitors (FTIs) was held in Naples on 12 April 2002 and represented an excellent occasion to gather most of the clinicians who are involved in clinical trials with this class of new compounds. Oncogene mutations of the gene occur in approximately 30% of all human cancers and may have prognostic significance. Ras protein is normally synthesized as pro-Ras, which undergoes a number of post-translational modifications, among which farnesylation. Processed Ras proteins localize to the inner surface of the plasma membrane, and function as a molecular switch that cycles between an inactive and an active form. When in its active form, either because of the binding of an external ligand or because of its constitutive activation, Ras activates several downstream effectors, such as Raf-1, Rac, Rho and phospahtidylinositol-3 kinase, which mediate important cellular functions, such as proliferation, cytoskeletal organization and others. Interruption of the Ras signaling pathway can be basically achieved in three ways, i.e. inhibition of Ras protein expression through antisense oligonucleotides, prevention of Ras membrane localization and inhibition of Ras downstream effectors. SCH 66336 (lonafarnib; Sarasar), a tricyclic orally active FTI, has been the first of these compounds to undergo clinical development. The toxicity profile observed in all completed phase I/II trials has been fairly similar, since gastrointestinal tract toxicity (nausea, vomiting and diarrhea) and fatigue have generally qualified as dose-limiting toxicity (DLT). One objective response in a patient with pretreated non-small cell lung cancer (NSCLC) was observed. Based on preclinical evidence of synergism between lonafarnib and other anticancer agents, combination studies have been started. In particular, lonafarnib has been combined both with gemcitabine and with paclitaxel in phase I studies. Nausea, vomiting, diarrhea and myelosuppression represented DLTs in these studies, in which an encouraging clinical activity was observed, in particular in pancreatic carcinoma (lonafarnib plus gemcitabine) and in NSCLC (lonafarnib plus paclitaxel). R115777 (Zarnestra) is another novel orally active FT competitive inhibitor in clinical development. Single-agent phase I/II studies have shown that myelotoxicity and neurotoxicity are DLTs, intermittent schedule is probably better tolerated and antitumor activity is observed particularly in breast canc

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Enzyme Inhibitors; Farnesyltranstransferase; Genes, ras; Humans; Piperidines; Pyridines; Quinolones

Farnesyl protein transferase inhibitors (FTIs) reverse the transformed phenotype of fibroblasts expressing activated H-Ras and block anchorage-independent growth and tumorigenesis of tumor cell lines independent of their Ras mutational status. FTIs induce significant tumor regression accompanied by apoptosis in several transgenic mouse tumor models. FTI treatment of tumor cells in vitro is proapoptotic under certain cell culture conditions. Induction of apoptosis by FTIs in vitro generally requires a second death-promoting signal. To better understand FTI-induced apoptosis we analyzed the effect of SCH 66336, a tricyclic FTI, on apoptosis of Ras-transformed Rat2 fibroblasts. Treatment of H-Ras-CVLS-transformed fibroblasts with MEK1,2 inhibitors provides a pharmacological second signal to enhance FTI-induced apoptosis. Simultaneous treatment of these cells with a MEK1,2 inhibitor markedly enhanced caspase-3 activity and the apoptotic response to SCH 66336. The combination treatment resulted in a more complete and sustained inhibition of MAPK pathway activity than observed with either drug alone. Surprisingly, after treatment with either agent alone or in combination, no apoptotic response was observed in Rat2 cells transformed with a geranylgeranylated form of H-Ras (H-Ras-CVLL). Differences were also observed when SCH 66336 treatment was combined with forced suspension growth or serum withdrawal, in that an increase in drug-induced apoptosis was observed in H-Ras-CVLS-transformed Rat2 cells but not H-Ras-CVLL-transformed Rat2 cells. The lack of apoptotic effect of SCH 66336 and MEK inhibitor, alone or in combination, in H-Ras-CVLL-transformed cells suggests a difference in the reliance of cells transformed with farnesylated and geranylgeranylated forms of H-Ras on the MAPK signal transduction cascade for survival. K-Ras-transformed cells underwent apoptosis upon MEK1,2 inhibition but not in response to SCH 66336 treatment. The apoptotic response induced by MEK1,2 inhibitors is much greater in magnitude in H-Ras-transformed cells than in K-Ras-transformed cells, also pointing to differences in pathway utilization and/or dependence for these two Ras isoforms.

Topics: Alkyl and Aryl Transferases; Animals; Apoptosis; Butadienes; Cell Line; Cell Line, Transformed; Enzyme Inhibitors; Fibroblasts; Flavonoids; MAP Kinase Kinase 1; MAP Kinase Kinase 2; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinase Kinases; Mitogen-Activated Protein Kinases; Nitriles; Phosphorylation; Piperidines; Protein Prenylation; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Proto-Oncogene Proteins p21(ras); Pyridines; Rats

SCH 66336 is a potent farnesyl transferase inhibitor (FTI) in clinical development. It efficiently prevents the membrane association of H-ras, but not K- or N-ras. Yet, in soft agar, it reverts the anchorage-independent growth of human tumor cell lines (hTCLs) harboring H-ras, K-ras, and N-ras mutations, implying that blocking farnesylation of proteins besides ras may be responsible for this effect. Experiments show that SCH 66336 altered the cell cycle distribution of sensitive human tumor cells in two distinct ways. Most sensitive hTCLs accumulated in the G(2)-->M phase after the FTI treatment, but those with an activated H-ras accumulated in G(1) phase, suggesting that the biological effects induced by FTIs in cells with an activated H-ras are distinct from other sensitive cells. A careful genotypic comparison of the hTCLs revealed that those cells with wild-type p53 are especially sensitive to the FTIs. In these cells p53 and its downstream target gene p21(Cip1) are induced after treatment with SCH 66336 for 24 h. These data suggest that cell cycle effects, either G(1) or G(2)-->M accumulation, and p53 status are important for mediating the effects of FTIs on tumor cells.

Topics: 3T3 Cells; Alkyl and Aryl Transferases; Animals; Cell Cycle; Cell Division; Cell Membrane; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Enzyme Inhibitors; Farnesyltranstransferase; G1 Phase; G2 Phase; Humans; K562 Cells; Kinetics; Mice; Mitosis; Molecular Structure; Oncogene Protein p21(ras); Piperidines; Pyridines; Tumor Cells, Cultured; Tumor Suppressor Protein p53

BCR/ABL, the oncoprotein responsible for chronic myeloid leukemia (CML), transforms hematopoietic cells through both Ras-dependent and -independent mechanisms. Farnesyl protein transferase inhibitors (FTIs) were designed to block mutant Ras signaling, but they also inhibit the growth of transformed cells with wild-type Ras, implying that other farnesylated targets contribute to FTI action. In the current study, the clinical candidate FTI SCH66336 was characterized for its ability to inhibit BCR/ABL transformation. When tested against BCR/ABL-BaF3 cells, a murine cell line that is leukemogenic in mice, SCH66336 potently inhibited soft agar colony formation, slowed proliferation, and sensitized cells to apoptotic stimuli. Quantification of activated guanosine triphosphate (GTP)-bound Ras protein and electrophoretic mobility shift assays for AP-1 DNA binding showed that Ras effector pathways are inhibited by SCH66336. However, SCH66336 was more inhibitory than dominant-negative Ras in assays of soft agar colony formation and cell proliferation, suggesting activity against targets other than Ras. Cell cycle analysis of BCR/ABL-BaF3 cells treated with SCH66336 revealed G2/M blockade, consistent with recent reports that centromeric proteins that regulate the G2/M checkpoint are critical farnesylated targets of FTI action. Mice injected intravenously with BCR/ABL-BaF3 cells developed acute leukemia and died within 4 weeks with massive splenomegaly, elevated white blood cell counts, and anemia. In contrast, nearly all mice treated with SCH66336 survived and have remained disease-free for more than a year. Furthermore, SCH66336 selectively inhibited the hematopoietic colony formation of primary human CML cells. As an oral, nontoxic compound with a mechanism of action distinct from that of ABL tyrosine kinase inhibition, FTI SCH66336 shows promise for the treatment of BCR/ABL-induced leukemia.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Apoptosis; Bone Marrow Cells; Cell Cycle; Cell Division; Enzyme Inhibitors; Farnesyltranstransferase; Genes, abl; Hematopoietic Stem Cells; Humans; Leukemia, Experimental; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Mice; Piperidines; Pyridines; Spleen; Survival Rate; Transformation, Genetic; Tumor Cells, Cultured

The Philadelphia (Ph) chromosome is found in approximately 3% of pediatric patients with acute lymphoblastic leukemia (ALL) and the percentage markedly increases in adult patients. The prognosis for this class of patients is poor, and no standard chemotherapy combination so far has demonstrated long-term efficacy. The Ph-translocation joins the BCR and ABL genes and leads to expression of a chimeric Bcr/Abl protein with enhanced tyrosine kinase activity. This increase in activity leads to malignant transformation by interference with basic cellular functions such as the control of proliferation, adherence to stroma and extracellular matrix, and apoptosis. One important pathway activated by Bcr/Abl is the Ras pathway. Ras proteins have to undergo a series of posttranslational modifications to become biologically active. The first modification is the farnesylation of the C-terminus catalyzed by farnesyl transferase. We studied the effect of the farnesyl transferase inhibitor SCH66336 in an in vivo murine model of Bcr/Abl-positive acute lymphoblastic leukemia. In the early leukemic phase, mice were randomly assigned to a treatment, a vehicle, and a nontreatment group. The treatment was well tolerated without any detectable side effects. All animals of the control groups died of leukemia/lymphoma within 103 days (range, 18-103 days). In contrast, 80% of the drug-receiving group survived without any signs of leukemia or lymphoma until termination of treatment, after a median treatment period of 200 days (range, 179-232 days). We conclude that farnesyl transferase inhibitor SCH66336 is able to revert early signs of leukemia and significantly prolongs survival in a murine ALL model.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Bone Marrow; Farnesyltranstransferase; Genes, abl; Mice; Mice, Transgenic; Piperidines; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Pyridines; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Survival Rate

The enzyme protein farnesyltransferase, which catalyzes the first step in the posttranslational modification of ras and a number of other polypeptides, has emerged as an important target for the development of anticancer agents. SCH66336 is one of the first farnesyltransferase inhibitors to undergo clinical testing. In the present study, we examined the effect of combining SCH66336 with several classes of antineoplastic drugs in various human tumor cell lines. Flow cytometry indicated that SCH66336 had no effect on the cell cycle distribution of treated cells. Nonetheless, colony-forming assays revealed that the antiproliferative effects of SCH66336 and 5-fluorouracil were less than additive. In contrast, the effects of SCH66336 and melphalan were additive. Moreover, the combination of SCH66336 + cisplatin produced antiproliferative effects that were additive or synergistic over a broad range of clinically achievable concentrations in A549 non-small cell lung cancer cells and T98G human glioblastoma cells, but less than additive in MCF-7 breast, HCT116 colon, or BxPC-3 pancreatic adenocarcinoma cells. Examination of the effect of drug sequencing in A549 cells revealed synergism when cells were exposed to SCH66336 and then cisplatin and antagonism when drugs were administered in the opposite order. The additive and synergistic effects resulted in enhanced apoptosis with the SCH66336 + cisplatin combination. Additional studies failed to show any effect of SCH66336 on the formation or removal of platinum-DNA adducts, raising the possibility that SCH66336 is affecting survival of cisplatin-treated cells downstream of the DNA lesions. These observations suggest that SCH66336 exhibits additive or synergistic effects when combined with cisplatin in a sequence- and cell line-dependent fashion. Additional preclinical and clinical study of this combination appears warranted.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Apoptosis; Cell Cycle; Cisplatin; DNA Adducts; Drug Combinations; Drug Synergism; Fluorouracil; Humans; Melphalan; Piperidines; Platinum; Pyridines; Tumor Cells, Cultured

Previous studies have demonstrated that astrocytomas express elevated levels of activated Ras.GTP despite the absence of activating Ras mutations. Farnesyl transferase inhibitors (FTIs) exert their antitumor effect in part through inhibition of Ras-mediated signaling. SCH66336 is a potent FTI presently undergoing clinical trials in patients with solid tumors. We evaluated the efficacy of SCH66336 against a panel of eight human astrocytoma cell lines and three human astrocytoma explant xenograft models in NOD-SCID mice. SCH66336 demonstrated variable antiproliferative effects against the cell lines, with IC(50) ranging from 0.6 microM to 32.3 microM. Two of the three human glioblastoma multiforme (GBM) xenografts demonstrated substantial growth inhibition in response to SCH66336, with up to 69% growth inhibition after 21 days of treatment. Drug efficacy could be accurately predicted using a combination of the H-, K-, and N-isotype-specific Ras.GTP levels. These data indicate that the absence of Ras mutations does not preclude chemotherapeutic efficacy by FTIs, that Ras is likely a major target of FTIs regardless of Ras mutational status, and that isotype-specific Ras.GTP levels are a promising marker of drug efficacy.

Topics: Alkyl and Aryl Transferases; Animals; Astrocytoma; Brain Neoplasms; Cell Division; Enzyme Inhibitors; Farnesyltranstransferase; Genes, ras; Glioblastoma; Guanosine Triphosphate; Humans; Immunohistochemistry; Mice; Mice, Inbred BALB C; Mice, Inbred NOD; Mice, Nude; Mice, SCID; Monomeric GTP-Binding Proteins; Mutation; Piperidines; Pyridines; ras Proteins; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

P-glycoprotein (Pgp)-mediated drug efflux is a major factor contributing to the variance of absorption and distribution of many drugs, particularly cancer chemotherapeutics. Multidrug resistance (MDR) is caused largely by the efflux of therapeutics out of the tumor cell by Pgp, resulting in reduced efficacy of chemotherapy. SCH66336, a farnesyl transferase inhibitor in development for cancer therapy, was examined in the present study for its ability to inhibit Pgp. In a test system consisting of a NIH-G185 cell line presenting an overexpressed amount of the human transporter Pgp, known Pgp inhibitors, such as cyclosporin A, paclitaxel, verapamil, tamoxifen, and vinblastine, were demonstrated to inhibit the Pgp-mediated efflux of daunorubicin. SCH66336 significantly inhibited daunorubicin transport with an IC50 of about 3 microM and similarly affected the transport of rhodamine 123 with a potency similar to cyclosporin A. Additionally, by an ATP-hydrolysis assay, SCH66336 was shown to decrease Pgp-mediated ATP hydrolysis by >70% with a Km of 3 microM. This observation indicates that SCH66336 directly interacts with the substrate binding site of Pgp, a quality unique to SCH66336 and its analogues, although not inherent to farnesyl transferase inhibitors in general. Moreover, low concentrations of SCH66336 exhibit synergy with the Pgp substrate/inhibitors paclitaxel, tamoxifen, and vinblastine respectively by significantly potentiating their inhibition of Pgp. Treatment with SCH66336 would be predicted to be synergistic with coadministered cancer therapeutics that are substrates of Pgp. A further benefit of coadministration of SCH66336 could be reduced chemotherapy dosage, hence, lower exposure to normal cells and, therefore, less undesired toxicity.

Topics: 3T3 Cells; Adenosine Triphosphate; Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport, Active; Cell Line; CHO Cells; Cricetinae; Daunorubicin; Drug Synergism; Enzyme Inhibitors; Farnesyltranstransferase; Genes, MDR; Humans; Hydrolysis; Mice; Paclitaxel; Piperidines; Pyridines; Rhodamine 123; Tamoxifen; Vinblastine

[reaction--see text] An efficient Grignard- and organolithium-induced regio- and chemoselective anionic acylation is reported. A number of tricyclic ketones are prepared in good to excellent yields via this method. This method is complementary to the Frieldel-Crafts acylation for electron-deficient substrates. A novel anisole-based Grignard reagent was developed to effect the cyclization of sterically hindered substrates. This novel reagent has been successfully applied to the synthesis of Sch 66336, a candidate for oncologic treatment.

Topics: Acylation; Antineoplastic Agents; Cyclization; Indicators and Reagents; Ketones; Piperidines; Pyridines

Human tumor cell lines that are sensitive to the effects of farnesyl transferase inhibitors accumulate in G(2) --> M (except for cells with an activated Ha-ras that accumulate in G(1)). A search for CAAX box proteins from Swiss-Prot revealed more than 300 peptides. Of these, the centromeric proteins CENP-E and CENP-F are preferentially expressed during mitosis and are implicated as mediators of the G(2) --> M checkpoint. Experiments performed here show that peptides from the COOH-terminal CAAX box of CENP-E and CENP-F are substrates for farnesyl transferase but not geranylgeranyl transferase-I. Although both proteins are prenylated in the human tumor cell line DLD-1, their prenylation is completely inhibited by the farnesyl transferase inhibitor, SCH 66336. Immunohistochemical data with the lung carcinoma cell line, A549, showed that preventing the farnesylation of CENP-E and CENP-F by treatment with the farnesyl transferase inhibitor SCH 66336 does not affect their localization to the kinetochores. However, the presence of farnesyl transferase inhibitors alters the association between CENP-E and the microtubules. Our results imply that the inhibition of CENP-E farnesylation results in the alteration of the microtubule-centromere interaction during mitosis and results in the accumulation of cells prior to metaphase.

Topics: Alkyl and Aryl Transferases; Cell Cycle; Chromosomal Proteins, Non-Histone; Enzyme Inhibitors; Humans; Mevalonic Acid; Microfilament Proteins; Microtubule-Associated Proteins; Microtubules; Piperidines; Protein Prenylation; Pyridines; Substrate Specificity; Tumor Cells, Cultured

Farnesyltransferase inhibitors (FTIs) were developed to target abnormal signaling pathways that are commonly activated in neoplastic cells. Five FTIs have recently undergone Phase I testing; and two are currently in Phase II clinical trials. As part of the development of these agents, there has been interest in determining their cellular effects in the clinical setting. Several approaches have been proposed, including measurement of FT enzymatic activity, evaluation of the processing of FT polypeptide substrates, and assessment of the accumulation of p21waf1. In the present study, a number of these assays have been compared in four cultured human neoplastic cell lines of different histology (A549, HCT116, BxPC-3, and MCF-7) after treatment with the nonpeptidomimetic FTI SCH66336 and the peptidomimetic inhibitor FTI-277. Immunoblotting studies failed to demonstrate a mobility shift in ras proteins or increased accumulation of p21waf1 after treatment with these agents. In contrast, drug-induced increases in the slower migrating, unprocessed species of the chaperone protein HDJ-2 and the intranuclear intermediate filament protein lamin A were detected in all four cell lines after treatment with either agent. Unprocessed forms of both polypeptides accumulated in noncycling as well as cycling cells. The precursor peptide that is present in prelamin A but absent from mature lamin A could be readily detected by immunohistochemistry in noncycling cells with a peptide-specific antiserum. Our results indicate that unprocessed HDJ-2 and prelamin A should be suitable markers of FT inhibition in clinical samples.

Topics: Alkyl and Aryl Transferases; Amino Acid Sequence; Antineoplastic Agents; Biomarkers, Tumor; Carrier Proteins; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Enzyme Inhibitors; Farnesyltranstransferase; Heat-Shock Proteins; HSP40 Heat-Shock Proteins; Humans; Immunoblotting; Immunohistochemistry; Inhibitory Concentration 50; Lamin Type A; Lamins; Methionine; Molecular Sequence Data; Nuclear Proteins; Peptides; Piperidines; Protein Precursors; Protein Prenylation; Pyridines; Signal Transduction; Transfection; Tumor Cells, Cultured

The resolution of secondary amines via enzyme-catalyzed acylation is a relatively rare process. The kinetic resolution of a series of intermediates of SCH66336 (1), by either enzymatic acylation of the pendant piperidine (4, 5) or hydrolysis of the corresponding carbamate 3, was investigated. In the case of 4, the molecule exists as a pair of enantiomers due to atropisomerism about the exocyclic double bond. The enzymatic acylation of (+/-)-4 was optimized in terms of acylating agent, solvent, and moisture content. The use of lipase, Toyobo LIP-300, and trifluoroethyl isobutyrate as acylating agent resulted in isobutyrylation of the (+)-enantiomer, which is easily separated from the unwanted (-)-4. Hydrolysis of the isobutyramide 6c yielded the desired (+)-4 in high enantiomeric excess. (-)-4 may be recovered from the resolution step, racemized, and resubjected to enzymatic acylation to increase material throughput.

Topics: Acylation; Alkyl and Aryl Transferases; Enzyme Inhibitors; Kinetics; Piperidines; Pyridines; Spectrum Analysis; Stereoisomerism

SCH66336 is an orally active, farnesyl protein transferase inhibitor. SCH66336 inhibits ras farnesylation in tumor cells and suppresses tumor growth in human xenograft and transgenic mouse cancer models in vivo. The taxanes, paclitaxel (Taxol) and docetaxel (Taxotere) block cell mitosis by enhancing polymerization of tubulin monomers into stabilized microtubule bundles, resulting in apoptosis. We hypothesized that anticancer combination therapy with SCH66336 and taxanes would be more efficacious than single drug therapy.. We tested the efficacy of SCH66336 and taxanes when used in combination against tumor cell proliferation in vitro, against NCI-H460 human lung tumor xenografts in nude mice, and against mammary tumors in wap-ras transgenic mice.. SCH66336 synergized with paclitaxel in 10 out of 11 tumor cells lines originating from breast, colon, lung, ovary, prostate, and pancreas. SCH66336 also synergized with docetaxel in four out of five cell lines tested. In the NCI-H460 lung cancer xenograft model, oral SCH66336 (20 mg/kg twice daily for 14 days) and intraperitoneal paclitaxel (5 mg/kg once daily for 4 days) caused a tumor growth inhibition of 56% by day 7 and 65% by day 14 compared to paclitaxel alone. Male transgenic mice of the wap-ras/F substrain [FVB/N-TgN(WapHRAS)69LlnYSJL] spontaneously develop mammary tumors at 6 9 weeks of age which have been previously shown to be resistant to paclitaxel. Paclitaxel resistance was confirmed in the present study, while SCH66336 inhibited growth of these tumors. Most importantly, SCH66336 was able to sensitize wap-ras/F mammary tumors to paclitaxel chemotherapy.. Clinical investigation of combination therapy using SCH66336 and taxanes in cancer patients is warranted. Further, SCH66336 may be useful for sensitizing paclitaxel-resistant tumors to taxane treatment.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents, Phytogenic; Cell Division; Docetaxel; Drug Synergism; Enzyme Inhibitors; Female; Gene Expression Regulation, Neoplastic; Genes, ras; Humans; Male; Mice; Mice, Nude; Mice, Transgenic; Paclitaxel; Piperidines; Pyridines; Taxoids; Tumor Cells, Cultured; Tumor Suppressor Protein p53

Ras activation occurs through stimulation of an upstream growth factor receptor such as epidermal growth factor receptor (EGFR). The ultimate effect of Ras is to induce nuclear transcription via a signaling pathway sequentially involving Raf, MAP kinase kinase (MEK), and mitogen-activated protein kinase (MAPK). To transform cells, Ras oncoproteins must be posttranslationally modified with a farnesyl group in a reaction catalyzed by farnesyl protein transferase. Farnesyltransferase inhibitors, therefore, have been proposed as potent anticancer agents. This study demonstrates the growth-inhibitory effects of farnesyltransferase inhibitor SCH66336 on human glioblastoma cell lines U-251 MG, U-251/E4 MG (a stably transfected cell line with elevated EGFR expression), and U-87 MG. As determined by (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) (MTS) and viability assays, the concentration required to achieve 50% inhibition (IC50) ranged from 30 microM (single 24-h treatment) to 10 microM (5-day treatment). U-251/E4 MG with overexpression of EGFR were more sensitive than U-251 MG parental cells. These observations were also supported by soft agar analysis. Cells treated with SCH66336 underwent G2 arrest. Western blot analysis revealed a decrease in phospho-MAPK levels upon treatment with 10 microM SCH66336, whereas MAPK levels were unaffected by the drug. Interestingly, increased expression of EGFR was observed in U-251 MG and U-251/E4 MG but not in U-87 MG in the presence of the inhibitor. These results demonstrate that SCH66336 inhibits viability and anchorage-independent growth in a time- and dose-dependent manner in glioblastoma cell lines U-251 MG, U-251/E4 MG, and U-87 MG via a signal transduction pathway involving the down-regulation of phospho-MAPK. Overexpression of EGFR appears to alter cellular sensitivity to farnesyltransferase inhibitors. This may have a particularly important implication in glioblastoma, where over 50% of tumors have amplification and overexpression of EGFR.

Topics: Alkyl and Aryl Transferases; Cell Division; Cell Survival; Enzyme Inhibitors; Farnesyltranstransferase; G2 Phase; Glioblastoma; Humans; Mitogen-Activated Protein Kinases; Piperidines; Pyridines; Tumor Cells, Cultured

[reaction: see text] A palladium-catalyzed highly regioselective one-step carbonylation of 2,5-dibromo-3-methylpyridine is reported. A range of alkyl esters and amides can be prepared in good yield with better than 95:5 regioselectivity via this method. Key to the high regioselectivity for the formation aromatic amides is the introduction of a novel nonphosphine-based 2,2-bipyridine ligand. This novel reaction was scaled up smoothly in the plant to a 130-kg batch size and facilitated the delivery of bulk material for the clinical trials of Sch 66336, a candidate for oncologic treatments.

Topics: Antineoplastic Agents; Catalysis; Indicators and Reagents; Ligands; Palladium; Piperidines; Pyridines

The ras gene product regulates transduction of growth-proliferative signals from the membrane to the nucleus. Mutationally-activated Ras is the oncogene most frequently found in human tumors. In order to perform its function in cell signaling, Ras must be farnesylated on the CAAX motif present on the carboxyl terminus of the ras protein. This reaction is catalysed by farnesyl protein transferase. In the present study, SCH 66336, an orally bioavailable nonpeptide tricyclic farnesyltransferase inhibitor, was tested against a large variety of human tumors to define its preclinical activity profile, utilizing the human tumor cloning assay.. A soft agar cloning assay was used to determine the in vitro effects of SCH 66336 against primary human tumor specimens taken directly from patients. A total of 70 evaluable specimens were exposed to SCH 66336 for 14-day continuous exposure at concentrations ranging from 0.1 to 2.5 microM. In vitro responses were defined as an inhibition > or = 50% of human tumor colony forming units at a given concentration.. There was a positive relationship between concentration and response to SCH 66336. With the highest concentration (2.5 microM), response was demonstrated in 50% (three of six) of breast tumors, 40% (6 of 15) of ovarian tumors, and 38% (5 of 13) of non-small-cell lung tumor colony forming units. Among the 69 specimens tested at the concentration of 2.5 microM, SCH 66336 had activity in 27% of tumor specimens that were resistant to doxorubicin, 38% of tumor specimens resistant to cisplatin, 33% of tumor specimens resistant to paclitaxel, and 27% of tumor specimens resistant to etoposide.. The broad spectrum of soft agar growth inhibition by SCH 66336 in the human tumor cloning assay, and its efficacy at physiologically relevant concentrations in animal models, suggest that SCH 66336 may deserve future clinical trials in patients with ovarian, breast and non-small-cell lung cancer.

Topics: Alkyl and Aryl Transferases; Cell Survival; Cisplatin; Clone Cells; Dose-Response Relationship, Drug; Doxorubicin; Drug Resistance, Neoplasm; Etoposide; Farnesyltranstransferase; Humans; Neoplasms; Neoplastic Stem Cells; Paclitaxel; Piperidines; Pyridines; Sensitivity and Specificity; Tumor Cells, Cultured; Tumor Stem Cell Assay

Crystallographic and thermodynamic studies of farnesyl protein transferase (FPT) complexed with novel tricyclic inhibitors provide insights into the observed SAR for this unique class of nonpeptidic FPT inhibitors. The crystallographic structures reveal a binding pattern conserved across the mono-, di-, and trihalogen series. In the complexes, the tricycle spans the FPT active site cavity and interacts with both protein atoms and the isoprenoid portion of bound farnesyl diphosphate. An amide carbonyl, common to the tricyclic compounds described here, participates in a water-mediated hydrogen bond to the protein backbone. Ten high-resolution crystal structures of inhibitors complexed with FPT are reported. Included are crystallographic data for FPT complexed with SCH 66336, a compound currently undergoing clinical trials as an anticancer agent (SCH 66336, 4-[2-[4-(3,10-dibromo-8-chloro-6,11-dihydro-5H-benzo[5, 6]cyclohepta[1, 2-b]pyridin-11-yl)-1-piperidinyl]-2-oxoethyl]-1-piperidinecarbo xamide ). Thermodynamic binding parameters show favorable enthalpies of complex formation and small net entropic contributions as observed for 4-[2-[4-(3,10-dibromo-8-chloro-6,11-dihydro-11H-benzo[5, 6]cyclohepta[1, 2-b]pyridin-11-ylidene)-1-piperidinyl]-2-oxoethyl]pyridine N-oxide where DeltaH degrees bind = -12.5 kcal/mol and TDeltaS degrees bind = -1.5 kcal/mol.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Binding Sites; Calorimetry; Crystallography, X-Ray; Cyclic N-Oxides; Enzyme Inhibitors; Heterocyclic Compounds, 3-Ring; Hydrogen Bonding; Models, Molecular; Piperidines; Protein Prenylation; Pyridines; Thermodynamics

SCH 66336 is a novel non-cytotoxic anti-tumor agent that is in phase I/II clinical trials for the treatment of solid tumors. This compound is a single enantiomer with one chiral center. Prior to evaluation of this drug candidate in man, it was necessary to evaluate its pharmacokinetics and possible chiral inversion in animals. Thus, high-performance liquid chromatographic (HPLC) methods have been developed for its determination in cynomolgus monkey plasma and for the evaluation of its chiral inversion in rats and cynomolgus monkeys. The achiral HPLC analysis involved extraction with 30% methylene chloride in hexane followed by separation on a CN column and quantitation by UV absorbance at 280 nm. The method was linear over a concentration range of 0.1 to 20 microg/ml in monkey plasma. The chiral HPLC analysis involved the use of a Chiralpak AD column set at 39 degrees C with a mobile phase of hexane-ethanol-diethylamine mixture and a UV detector set at 280 nm. Plasma samples were subjected to solid-phase extraction on a C2 cartridge prior to HPLC analysis. The method was linear over a concentration range of 0.25 to 10 microg/ml in rat and cynomolgus monkey plasma for both enantiomers. Both methods showed good linearity (r2>0.99), accuracy (bias< 13%) and precision (CV<12%). Chiral HPLC analysis indicated that SCH 66336 was not subjected to chiral inversion in rats and cynomolgus monkeys.

Topics: Animals; Antineoplastic Agents; Area Under Curve; Calibration; Chromatography, High Pressure Liquid; Macaca fascicularis; Male; Piperidines; Pyridines; Rats; Reproducibility of Results; Sensitivity and Specificity; Spectrophotometry, Ultraviolet; Stereoisomerism

A series of 3-substituted analogs 3 of 4-(3-bromo-8-methyl-10-methoxy-6,11-dihydro-5H-benzo[5,6]-cyclohepta[1,2 b]pyridin-11-yl)-1-(4-pyridinylacetyl)piperidine N-oxide 2 was prepared and evaluated as FPT inhibitors. The objective of this study was to identify other substituents at C3 in this series of FPT inhibitors that would have the FPT potency enhancement similar to that found for a C3 bromo substituent. The 3-methyl analog 17b was found to be tenfold less active than 2, and other C3 substituents having more steric bulk were found to cause a further reduction in activity.

Topics: Alkyl and Aryl Transferases; Enzyme Inhibitors; Inhibitory Concentration 50; Piperidines; Pyridines

Farnesyl protein transferase (FPT) is a promising target for the development of cancer chemotherapeutics because it is responsible for the farnesylation of oncogenic p21 Ras proteins which are found in nearly 30% of all human cancers and necessary for cellular development and growth. The recent discovery and progression to phase II clinical trials of trihalobenzocycloheptapyridine Sch-66336 as a potent inhibitor of FPT with oral, in vivo efficacy in mice have spawned extensive structure-activity relationship studies (SAR) of this class of compounds. Of the many trihalobenzocycloheptapyridine analogues prepared, we have identified several which inhibit FPT and cellular proliferation at single-digit nanomolar concentrations and which have good pharmacokinetic properties in mice.

Topics: Administration, Oral; Alkyl and Aryl Transferases; Animals; Biological Availability; Cell Division; COS Cells; Enzyme Inhibitors; Haplorhini; Mice; Mice, Nude; Piperidines; Protein Prenylation; Proto-Oncogene Proteins p21(ras); Pyridines; Structure-Activity Relationship; Sulfonamides; Sulfonylurea Compounds

SCH66336 is a p.o.-active, farnesyl protein transferase inhibitor. SCH66336 inhibits farnesylation of RAS and other proteins in tumor cells and suppresses tumor growth in human xenograft and transgenic mouse cancer models in vivo. SCH58500 is a replication-deficient, recombinant adenovirus, which expresses the human p53 tumor suppressor. In preclinical models, SCH58500 has therapeutic efficacy against a wide range of human tumor types containing nonfunctional p53 and enhanced activity in combination with many chemotherapeutic drugs. Here we report that combination therapy with SCH66336 and SCH58500 has synergistic or additive antiproliferative effects on a panel of tumor cells lines in vitro. The efficacy of the three-drug combination of SCH66336, SCH58500, and paclitaxel was also examined in vitro. Each two-drug interaction displayed such marked synergy, the addition of a third drug to the statistical model could only yield additivity. Greater combined efficacy for SCH66336 and SCH58500 was also observed in vivo in the DU-145 human prostate and wap-ras/F transgenic mouse cancer models.

Topics: Adenocarcinoma; Adenoviruses, Human; Alkyl and Aryl Transferases; Animals; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Cell Survival; Drug Synergism; Female; Genes, ras; Humans; Male; Mice; Mice, Nude; Mice, SCID; Mice, Transgenic; Ovarian Neoplasms; Paclitaxel; Pancreatic Neoplasms; Piperidines; Prostatic Neoplasms; Pyridines; Teratocarcinoma; Tumor Cells, Cultured; Tumor Suppressor Protein p53

We have been developing a series of nonpeptidic, small molecule farnesyl protein transferase inhibitors that share a common tricyclic nucleus and compete with peptide/protein substrates for binding to farnesyl protein transferase. Here, we report on pharmacological and in vivo studies with SCH 66336, a lead compound in this structural class. SCH 66336 potently inhibits Ha-Ras processing in whole cells and blocks the transformed growth properties of fibroblasts and human tumor cell lines expressing activated Ki-Ras proteins. The anchorage-independent growth of many human tumor lines that lack an activated ras oncogene is also blocked by treatment with SCH 66336. In mouse, rat, and monkey systems, SCH 66336 has excellent oral bioavailability and pharmacokinetic properties. In the nude mouse, SCH 66336 demonstrated potent oral activity in a wide array of human tumor xenograft models including tumors of colon, lung, pancreas, prostate, and urinary bladder origin. Enhanced in vivo efficacy was observed when SCH 66336 was combined with various cytotoxic agents (cyclophosphamide, 5-fluorouracil, and vincristine). In a Ha-Ras transgenic mouse model, prophylactic treatment with SCH 66336 delayed tumor onset, reduced the average number of tumors/mouse, and reduced the average tumor weight/animal. In a therapeutic mode in which gavage treatment was initiated after the transgenic mice had developed palpable tumors, significant tumor regression was induced by SCH 66336 in a dose-dependent fashion. This was associated with increased apoptosis and decreased DNA synthesis in tumors of animals treated with SCH 66336. Enhanced efficacy was also observed in this model when SCH 66336 was combined with cyclophosphamide. SCH 66336 is presently being evaluated in Phase I clinical trials.

Topics: 3T3 Cells; Administration, Oral; Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; Bromodeoxyuridine; Cell Division; Dose-Response Relationship, Drug; Enzyme Inhibitors; Female; Genes, ras; Humans; Macaca fascicularis; Male; Mice; Neoplasm Transplantation; Neoplasms, Experimental; Piperidines; Pyridines; Rats; Transplantation, Heterologous

We have previously shown that appropriate modification of the benzocycloheptapyridine tricyclic ring system can provide potent farnesyl protein transferase (FPT) inhibitors with good cellular activity. Our laboratories have also established that incorporation of either pyridinylacetyl N-oxide or 4-N-carboxamidopiperidinylacetyl moieties results in pharmacokinetically stable inhibitors that are orally efficacious in nude mice. We now demonstrate that further elaboration of the tricyclic ring system by introducing a bromine atom at the 7- or the 10-position of the 3-bromo-8-chlorotricyclic ring system provides compounds that have superior potency and selectivity in FPT inhibition. These compounds have good serum levels and half-lives when given orally to rodents and primates. In vitro and in vivo evaluation of a panel of these inhibitors has led to identification of 15 (SCH 66336) as a highly potent (IC50 = 1.9 nM) antitumor agent that is currently undergoing human clinical trials.

Topics: Alkyl and Aryl Transferases; Animals; Antineoplastic Agents; COS Cells; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Humans; Macaca fascicularis; Mice; Mice, Nude; Piperidines; Protein Prenylation; Pyridines; Stereoisomerism; Structure-Activity Relationship; Tumor Cells, Cultured