sta-9090 and Colorectal-Neoplasms

Heat shock protein 90 (Hsp90) is a cellular chaperone that is required for the maturation and stability of a variety of proteins that play key roles in colon cancer initiation and progression. The primary objective of the current study was to define the safety and efficacy of ganetespib, a novel, selective small-molecule Hsp90 inhibitor, in patients with refractory metastatic colorectal cancer.. The study was a single-arm, Simon 2-stage, phase II trial for patients with chemotherapy-refractory, metastatic colorectal cancer. Patients received ganetespib 200 mg/m(2) intravenously. Tumor tissue was collected before treatment and 48 hours after treatment for changes in expression of Hsp90 client proteins and other potential pharmacodynamics markers. V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), v-Raf murine sarcoma viral oncogene homolog B, and phosphatidylinositol-4, 5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) mutational status was also determined.. Seventeen patients were treated (median age, 58; range, 44-79 years). No patients demonstrated objective regression of disease. Two patients had stable disease of 6.8 and 5.1 months duration. Serious adverse events that were potentially attributable to ganetespib included diarrhea (12%, n = 2), fatigue (17%, n = 3), and increased aspartate aminotransferase/alanine aminotransferase (12%, n = 2) and alkaline phosphatase (6%, n = 1) levels. Of the 17 evaluable patients, 9 (53%) including patients with stable disease as best response, had KRAS-mutant tumors.. In this first phase II investigation of an Hsp90 inhibitor in colorectal cancer, ganetespib as a single agent did not demonstrate activity in chemotherapy-refractory metastatic colorectal cancer. However, on the basis of the drug's promising preclinical combination data and the relatively mild toxicity profile, further clinical investigation of this agent in combination with standard cytotoxic agents is planned.

Topics: Adult; Aged; Biomarkers, Tumor; Colorectal Neoplasms; Drug Resistance, Neoplasm; Female; Follow-Up Studies; HSP90 Heat-Shock Proteins; Humans; Immunoenzyme Techniques; Male; Middle Aged; Mutation; Neoplasm Metastasis; Neoplasm Staging; Prognosis; Proto-Oncogene Proteins; Proto-Oncogene Proteins p21(ras); ras Proteins; Salvage Therapy; Survival Rate; Triazoles

A major cause of failure of therapy in patients with non-small cell lung cancer (NSCLC) is development of acquired drug resistance leading to tumor recurrence and disease progression. In addition to the development of new generations of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), different molecular targets may provide opportunities to improve the therapeutic outcomes. In this study, we utilized the core structure 5-fluorouracil (5-FU) or tegafur, a 5-FU prodrug combined through different linkers with resorcinol to generate a series of fluoropyrimidin-2,4-dihydroxy-5-isopropylbenzamides which inhibit potent Heat Shock Protein 90 (HSP90). These compounds were found to show significant antiproliferative activity in colorectal cancer (CRC) HCT116 and NSCLC A549, H460, and H1975 (EGFR L858R/T790 M double mutation) cells. Compound 12c, developed by molecular docking analysis and enzymatic assays exhibits promising inhibitory activity of HSP90. This compound, 12c shows the most potent HSP90 inhibitory activity with an IC

Topics: Antineoplastic Agents; Apoptosis; Benzamides; Carcinoma, Non-Small-Cell Lung; Caspases; Cell Line, Tumor; Colorectal Neoplasms; Cytoprotection; Enzyme Activation; ErbB Receptors; Humans; Inhibitory Concentration 50; Lung Neoplasms; Mutation; Proteolysis; Proto-Oncogene Proteins c-akt

The integration of targeted agents to standard cytotoxic regimens has improved outcomes for patients with colorectal cancer (CRC) over recent years; however this malignancy remains the second leading cause of cancer mortality in industrialized countries. Small molecule inhibitors of heat shock protein 90 (HSP90) are one of the most actively pursued classes of compounds for the development of new cancer therapies. Here we evaluated the activity of ganetespib, a second-generation HSP90 inhibitor, in models of CRC. Ganetespib reduced cell viability in a panel of CRC cell lines in vitro with low nanomolar potency. Mechanistically, drug treatment exerted concomitant effects on multiple oncogenic signaling pathways, cell cycle regulation, and DNA damage repair capacity to promote apoptosis. Combinations of ganetespib and low-dose ionizing radiation enhanced the radiosensitivity of HCT 116 cells and resulted in superior cytotoxic activity over either treatment alone. In vivo, the single-agent activity of ganetespib was relatively modest, suppressing HCT 116 xenograft tumor growth by approximately half. However, ganetespib significantly potentiated the antitumor efficacy of the 5-Fluorouracil (5-FU) prodrug capecitabine in HCT 116 xenografts, causing tumor regressions in a model that is intrinsically resistant to fluoropyrimidine therapy. This demonstration of combinatorial benefit afforded by an HSP90 inhibitor to a standard CRC adjuvant regimen provides an attractive new framework for the potential application of ganetespib as an investigational agent in this disease.

Topics: Animals; Antineoplastic Agents; Apoptosis; Capecitabine; Cell Cycle; Cell Line, Tumor; Cell Survival; Chemotherapy, Adjuvant; Colorectal Neoplasms; Deoxycytidine; DNA Damage; DNA Repair; Female; Fluorouracil; HCT116 Cells; HSP90 Heat-Shock Proteins; Humans; Mice; Mice, Nude; Radiation-Sensitizing Agents; Radiation, Ionizing; Signal Transduction; Triazoles; Xenograft Model Antitumor Assays

HSP90 inhibition represents a promising route to cancer therapy, taking advantage of cancer cell-inherent proteotoxic stress. The HSP90-inhibitor ganetespib showed benefit in advanced clinical trials. This raises the need to identify the molecular determinants of treatment response. We tested the efficacy of ganetespib on a series of colorectal cancer (CRC)-derived cell lines and correlated their sensitivities with comprehensive gene expression analysis. Notably, the drug concentration required for 50% growth inhibition (IC50) varied up to 70-fold (from 36 to 2500 nM) between different cell lines. Correlating cell line-specific IC50s with the corresponding gene expression patterns revealed a strong association between ganetespib resistance (IC50>500 nM) and high expression of the UDP glucuronosyltransferase 1A (UGT1A) gene cluster. Moreover, CRC tumor samples showed a comparable distribution of UGT1A expression levels. The members of the UGT1A gene family are known as drug-conjugating liver enzymes involved in drug excretion, but their function in tumor cells is hardly understood. Chemically unrelated HSP90 inhibitors, for example, 17-N-allylamino-17-demethoxygeldanamycin (17-AAG), did not show correlation of drug sensitivities with UGT1A levels, whereas the ganetespib-related compound NVP-AUY922 did. When the most ganetespib-resistant cell line, HT29, was treated with ganetespib, the levels of HSP90 clients were unaffected. However, HT29 cells became sensitized to the drug, and HSP90 client proteins were destabilized by ganetespib upon siRNA-mediated UGT1A knockdown. Conversely, the most ganetespib-sensitive cell lines HCT116 and SW480 became more tolerant toward ganetespib upon UGT1A overexpression. Mechanistically, ganetespib was rapidly glucuronidated and excreted in resistant but not in sensitive CRC lines. We conclude that CRC cell-expressed UGT1A inactivates ganetespib and other resorcinolic Hsp90 inhibitors by glucuronidation, which renders the drugs unable to inhibit Hsp90 and thereby abrogates their biological activity. UGT1A levels in tumor tissues may be a suitable predictive biomarker to stratify CRC patients for ganetespib treatment.

Topics: Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Colorectal Neoplasms; Glucuronosyltransferase; HSP90 Heat-Shock Proteins; Humans; Triazoles

Cell cycle progression and DNA synthesis are essential steps in cancer cell growth. Thymidylate synthase (TS) is a therapeutic target for 5FU. We tested the hypothesis that HSP90 transcriptional and functional inhibition can inhibit cell cycle progression, downregulate TS levels and sensitize colorectal cancer (CRC) cell lines to the effects of 5FU. Treatment with ganetespib (50 nM) for 24 hours inhibited cyclin D1 and pRb at the transcriptional and translational levels and induced p21, leading to G0/G1 cell cycle arrest in both CRC cell lines (HCT-116 and HT-29). This was associated with downregulation of E2F1 and its target gene TS. In addition, ganetespib inhibited PI3K/Akt and ERK signalling pathways. Similar effects were observed with HSP90 knockdown in both cell lines. Ganetespib sensitized CRC cell lines to the effects of oxaliplatin and 5FU. Similar effects were also observed in tumors from animals treated with ganetespib, oxaliplatin and 5FU. In this study, we present in vitro and animal data supporting that the targeting of HSP90 decreases CRC cell survival and proliferation. Ganetespib sensitizes CRC cell lines to the effects of 5FU-based chemotherapy. Combining HSP90 inhibitors with chemotherapy is a rational approach for future drug development in CRC.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Cycle Proteins; Colorectal Neoplasms; Down-Regulation; Drug Synergism; Female; Fluorouracil; HCT116 Cells; HSP90 Heat-Shock Proteins; HT29 Cells; Humans; Mice; Mice, Nude; Molecular Targeted Therapy; Organoplatinum Compounds; Oxaliplatin; RNA, Small Interfering; Thymidylate Synthase; Transfection; Triazoles; Xenograft Model Antitumor Assays

Hypoxia-inducible factors (HIFs) and STAT-3 play essential roles in angiogenesis. HIF-1α and STAT-3 are clients of the heat shock protein 90 (HSP90). We hypothesized that ganetespib, a potent HSP90 inhibitor, would disrupt angiogenesis in colorectal cancer (CRC) through inhibition of HIF-1α and STAT-3. CRC cell lines (HCT116 and HT29) were used in all the experiments. Egg CAM and HUVEC assays revealed decreased angiogenesis in ganetespib treated cell lines. Ganetespib inhibited matrigel plug vascularization and tumor growth of xenografts. Significant inhibition of PDGFA, FGF2, Ang-1, Ang-2, TGFβ1, VEGF, HIF-1α and STAT-3 expression was observed in both cell lines treated ganetespib. HIF-1α overexpression resulted in the increase VEGF and STAT-3 expression and this was inhibited by ganetespib. HIF-1α knockdown inhibited VEGF and STAT-3 expression. STAT-3 knockdown inhibited VEGF but not HIF-1α expression. HSP90, STAT-3 and VEGF expression was significantly higher in CRC compared to adjacent normal tissue. Significant downregulation of PDGFA, FGF2, Ang-1, Ang-2, TGFβ1, VEGF, STAT-3 and HIF-1α mRNA was observed in the post ganetespib treatment tumor samples from patients with rectal cancer. These results collectively suggest that inhibition of HSP90 is a promising antiangiogenic strategy in CRC. HSP90 angiogenic effects are mediated through HIF-1α and STAT-3.

Topics: Adenocarcinoma; Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Cell Line, Tumor; Chick Embryo; Chorioallantoic Membrane; Collagen; Colorectal Neoplasms; Down-Regulation; Drug Combinations; Female; Fibroblast Growth Factor 2; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; HEK293 Cells; HSP90 Heat-Shock Proteins; Human Umbilical Vein Endothelial Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Laminin; Mice, Nude; Platelet-Derived Growth Factor; Proteoglycans; Rectal Neoplasms; Ribonuclease, Pancreatic; RNA, Messenger; Specific Pathogen-Free Organisms; STAT3 Transcription Factor; Transforming Growth Factor beta1; Triazoles; Vascular Endothelial Growth Factor A; Vesicular Transport Proteins; Xenograft Model Antitumor Assays