piperidines and tanespimycin

The incidence of thyroid cancer continues to increase and this neoplasia remains the most common endocrine malignancy. No effective systemic treatment currently exists for iodine-refractory differentiated or medullary thyroid carcinoma, but recent advances in the pathogenesis of these diseases have revealed key targets that are now being evaluated in the clinical setting. RET (rearranged during transfection)/PTC (papillary thyroid carcinoma) gene rearrangements, B-Raf gene mutations, and vascular endothelial growth factor receptor 2 (VEGFR-2) angiogenesis pathways are some of the known genetic alterations playing a crucial role in the development of thyroid cancer. Several novel agents have demonstrated promising responses. Of the treatments studied, multi-kinase inhibitors such as axitinib, sorafenib, motesanib, and XL-184 have shown to be the most effective by inducing clinical responses and stabilizing the disease process. Randomized clinical trials are currently evaluating these agents, results that may soon change the management of thyroid cancer.

Topics: Angiogenesis Inhibitors; Anilides; Antineoplastic Agents; Axitinib; Benzamides; Benzenesulfonates; Benzoquinones; Bibenzyls; Boronic Acids; Bortezomib; Depsipeptides; ErbB Receptors; Gefitinib; Histone Deacetylase Inhibitors; HSP90 Heat-Shock Proteins; Humans; Hydroxamic Acids; Imatinib Mesylate; Imidazoles; Indazoles; Indoles; Lactams, Macrocyclic; Lenalidomide; Niacinamide; Oligonucleotides; Phenylurea Compounds; Piperazines; Piperidines; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-kit; Pyrazines; Pyridines; Pyrimidines; Pyrroles; Quinazolines; Quinolines; Receptor Protein-Tyrosine Kinases; Receptors, Vascular Endothelial Growth Factor; Sorafenib; Sulfonamides; Sunitinib; Thalidomide; Thyroid Neoplasms; Valproic Acid; Vorinostat

The first-generation ALK tyrosine kinase inhibitor (TKI) crizotinib is a standard therapy for patients with ALK-rearranged non-small cell lung cancer (NSCLC). Several next-generation ALK-TKIs have entered the clinic and have shown promising activity in crizotinib-resistant patients. As patients still relapse even on these next-generation ALK-TKIs, we examined mechanisms of resistance to the next-generation ALK-TKI alectinib and potential strategies to overcome this resistance.. We established a cell line model of alectinib resistance, and analyzed a resistant tumor specimen from a patient who had relapsed on alectinib. We developed Ba/F3 models harboring alectinib-resistant ALK mutations and evaluated the potency of other next-generation ALK-TKIs in these models. We tested the antitumor activity of the next-generation ALK-TKI ceritinib in the patient with acquired resistance to alectinib. To elucidate structure-activity relationships of ALK mutations, we performed computational thermodynamic simulation with MP-CAFEE.. We identified a novel V1180L gatekeeper mutation from the cell line model and a second novel I1171T mutation from the patient who developed resistance to alectinib. Both ALK mutations conferred resistance to alectinib as well as to crizotinib, but were sensitive to ceritinib and other next-generation ALK-TKIs. Treatment of the patient with ceritinib led to a marked response. Thermodynamics simulation suggests that both mutations lead to distinct structural alterations that decrease the binding affinity with alectinib.. We have identified two novel ALK mutations arising after alectinib exposure that are sensitive to other next-generation ALK-TKIs. The ability of ceritinib to overcome alectinib-resistance mutations suggests a potential role for sequential therapy with multiple next-generation ALK-TKIs.

Topics: Anaplastic Lymphoma Kinase; Benzoquinones; Carbazoles; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Crizotinib; DNA Mutational Analysis; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; HSP90 Heat-Shock Proteins; Humans; Inhibitory Concentration 50; Lactams, Macrocyclic; Lung Neoplasms; Models, Molecular; Mutation; Piperidines; Protein Conformation; Protein Kinase Inhibitors; Pyrazoles; Pyridines; Receptor Protein-Tyrosine Kinases; Tomography, X-Ray Computed

Histone H1 is commonly used to assay kinase activity in vitro. As many promising targeted therapies affect kinase activity of specific enzymes involved in cancer transformation, H1 phosphorylation can serve as potential pharmacodynamic marker for drug activity within the cell. In this study we utilized a phosphoproteomic workflow to characterize histone H1 phosphorylation changes associated with two targeted therapies in the Kasumi-1 acute myeloid leukemia cell line. The phosphoproteomic workflow was first validated with standard casein phosphoproteins and then applied to the direct analysis of histone H1 from Kasumi-1 nuclear lysates. Ten H1 phosphorylation sites were identified on the H1 variants, H1.2, H1.3, H1.4, H1.5 and H1.x. LC MS profiling of intact H1s demonstrated global dephosphorylation of H1.5 associated with therapy by the cyclin-dependent kinase inhibitor, flavopiridol and the Heat Shock Protein 90 inhibitor, 17-(Allylamino)-17-demethoxygeldanamycin. In contrast, independent treatments with a nucleotide analog, proteosome inhibitor and histone deacetylase inhibitor did not exhibit decreased H1.5 phosphorylation. The data presented herein demonstrate that potential of histones to assess the cellular response of reagents that have direct and indirect effects on kinase activity that alters histone phosphorylation. As such, this approach may be a highly informative marker for response to targeted therapies influencing histone phosphorylation.

Topics: Amino Acid Sequence; Benzoquinones; Biomarkers, Pharmacological; Caseins; Flavonoids; Histones; HSP90 Heat-Shock Proteins; Humans; Lactams, Macrocyclic; Leukemia, Myeloid, Acute; Molecular Sequence Data; Molecular Targeted Therapy; Phosphopeptides; Piperidines; Protein Kinase Inhibitors; Tumor Cells, Cultured

Selective modulation of cell death is important for rational chemotherapy. By depleting Hsp90-client oncoproteins, geldanamycin (GA) and 17-allylamino-17-demethoxy-GA (17-AAG) (heat-shock protein-90-active drugs) render certain oncoprotein-addictive cancer cells sensitive to chemotherapy. Here we investigated effects of GA and 17-AAG in apoptosis-prone cells such as HL60 and U937. In these cells, doxorubicin (DOX) caused rapid apoptosis, whereas GA-induced heat-shock protein-70 (Hsp70) (a potent inhibitor of apoptosis) and G1 arrest without significant apoptosis. GA blocked caspase activation and apoptosis and delayed cell death caused by DOX. Inhibitors of translation and transcription and siRNA Hsp70 abrogated cytoprotective effects of GA. Also GA failed to protect HL60 cells from cytotoxicity of actinomycin D and flavopiridol (FL), inhibitors of transcription. We next compared cytoprotection by GA-induced Hsp70, caspase inhibitors (Z-VAD-fmk) and cell-cycle arrest. Whereas cell-cycle arrest protected HL60 cells from paclitaxel (PTX) but not from FL and DOX, Z-VAD-fmk prevented FL-induced apoptosis but was less effective against DOX and PTX. Thus, by inducing Hsp70, GA protected apoptosis-prone cells in unique and cell-type selective manner. Since GA does not protect apoptosis-reluctant cancer cells, we envision a therapeutic strategy to decrease side effects of chemotherapy without affecting its therapeutic efficacy.

Topics: Amino Acid Chloromethyl Ketones; Antibiotics, Antineoplastic; Apoptosis; Benzoquinones; Caspase 9; Caspase Inhibitors; Cell Cycle; Cell Line, Tumor; Cytoprotection; Dactinomycin; Doxorubicin; Enzyme Activation; Flavonoids; HSP70 Heat-Shock Proteins; Humans; Lactams, Macrocyclic; Paclitaxel; Piperidines; Protein Biosynthesis; RNA, Small Interfering; Transcriptional Activation

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