gdc-0449 and Prostatic-Neoplasms--Castration-Resistant

Hedgehog (Hh) pathway signaling has been implicated in prostate cancer tumorigenesis and metastatic development and may be upregulated even further in the castration-resistant state. We hypothesized that antagonism of the Hh pathway with vismodegib in men with metastatic castration-resistant prostate cancer (mCRPC) would result in pathway engagement, inhibition and perhaps induce measurable clinical responses in patients.. This is a single-arm study of oral daily vismodegib in men with mCRPC. All patients were required to have biopsies of the tumor and skin (a surrogate tissue) at baseline and after 4 weeks of therapy. Ten patients were planned for enrollment. The primary outcome was the pharmacodynamic assessment of Gli1 mRNA suppression with vismodegib in tumor tissue. Secondary outcomes included PSA response rates, progression-free survival (PFS), overall survival (OS) and safety.. Nine patients were enrolled. Gli1 mRNA was significantly suppressed by vismodegib in both tumor tissue (4/7 evaluable biopsies, 57%) and benign skin biopsies (6/8 evaluable biopsies, 75%). The median number of treatment cycles completed was three, with a median PFS of 1.9 months (95% CI 1.3, NA), and a median OS of 7.04 months (95% CI 3.4, NA). No patient achieved a PSA reduction or a measurable tumor response. Safety data were consistent with the known toxicities of vismodegib.. Hh signaling, as measured by Gli1 mRNA expression in mCRPC tissues, was suppressed with vismodegib in the majority of patients. Despite this pharmacodynamic response that indicated target inhibition in some patients, there was no apparent signal of clinical activity. Vismodegib will not be developed further as monotherapy in mCRPC.

Topics: Aged; Anilides; Hedgehog Proteins; Humans; Male; Middle Aged; Prostate-Specific Antigen; Prostatic Neoplasms, Castration-Resistant; Pyridines; Zinc Finger Protein GLI1

Epithelial-mesenchymal transition (EMT) via Sonic Hedgehog (Shh) signaling may be one of the mechanisms of progression of castration-resistant prostate cancer (CRPC). In this study, we investigated the possible therapeutic effect of vismodegib, a new Shh inhibitor, in a mouse CRPC model.. We determined cell proliferation, apoptosis and the expression of EMT-related genes for three prostate cancer cell lines; androgen-dependent LNCaP and independent C4-2B and PC-3 in the presence of vismodegib in vitro. Fifty mg/kg of vismodegib were orally administered into mice bearing C4-2B and PC-3 tumors, respectively every other week for 3 weeks.. Vismodegib significantly inhibited cell proliferation and induced cell apoptosis in all cell lines in vitro (p<0.05). Vismodegib significantly inhibited EMT in CRPC cells and tumor growth in C4-2B-bearing mice compared to controls in vivo (p<0.05). Higher expression of caspase-3 and lower expression of vimentin in PC-3 and C4-2B tumors were induced by vismodegib in immunohistochemical analysis.. Vismodegib inhibited cell proliferation via apoptosis and also suppressed EMT, showing anti-tumor effects in mice. Further mechanistic studies are needed to investigate the feasibility of vismodegib for CRPC treatment.

Topics: Anilides; Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Epithelial-Mesenchymal Transition; Hedgehog Proteins; Humans; Immunohistochemistry; Immunophenotyping; Male; Mice; Prostatic Neoplasms, Castration-Resistant; Pyridines; Signal Transduction; Xenograft Model Antitumor Assays

The establishment of docetaxel-based chemotherapeutic treatments has improved the survival of castration-resistant prostate cancer (CRPC) patients. However, most patients develop resistance supporting the development of therapy. The current study was undertaken to establish the therapeutic benefit to target hedgehog signaling cascade using GDC-0449 to improve the efficacy of chemotherapeutic drug, docetaxel. Here, we show that the combination of GDC-0449 plus docetaxel inhibited the proliferation of WPE1-NB26 cells and PC3 cells via a blockade of G1 and G2M phases. The combined treatment significantly inhibited PC cell migration in vitro. Moreover, the apoptotic effect induced by GDC-0449 plus docetaxel on PC3 cells was mediated, at least partly, via the mitochondrial membrane depolarization, H2O2 production and caspase cascade activation. Interestingly, GDC-0449 was effective at inhibiting the prostasphere formation, inducing the prostasphere disintegration and apoptotic death of side population (SP) from PC3 cells and reversing the resistance of SP cells to docetaxel. In addition, GDC-0449 plus docetaxel also have shown a greater anti-tumoral growth inhibitory effect on PC3 cell xenografts. These findings support the use of the hedgehog inhibitor GDC-0449, which is currently in clinical trials, for improving the anticarcinogenic efficacy of docetaxel-based chemotherapeutic treatments against locally advanced, AI and metastatic PC.

Topics: Anilides; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Proliferation; Docetaxel; Drug Synergism; Hedgehog Proteins; Humans; Male; Mice; Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant; Pyridines; Random Allocation; Signal Transduction; Taxoids; Xenograft Model Antitumor Assays