Similar Datasets
Project description:Androgen deprivation therapy for prostate cancer (PCa) benefits patients with early disease, but becomes ineffective as PCa progresses to a castration-resistant state (CRPC). Initially CRPC remains dependent on androgen receptor (AR) signaling, often through increased expression of full-length AR (ARfl) or expression of dominantly active splice variants such as ARv7. We show in ARv7-dependent CRPC models that ARv7 binds together with ARfl to repress transcription of a set of growth-suppressive genes. Expression of the ARv7-repressed targets and ARv7 protein expression are negatively correlated and predicts for outcome in PCa patients. Our results provide insights into the role of ARv7 in CRPC and define a set of potential biomarkers for tumors dependent on ARv7.
| S-EPMC7246081 | biostudies-literature
Project description:Endocrine therapies in prostate cancer (PCa) treatment block androgen receptor (AR) function, but are palliative as tumors progress to a lethal, castration-resistant state (CRPC). CRPC remains dependent on AR signaling, which can act through the full-length AR (ARfl) or constitutively active splice variants, e.g. ARv7. We show here that both ARfl and ARv7 bind to the same genomic region and heterodimerize in a CRPC cell line model, but regulate distinct transcriptomes. ARv7, unlike ARfl, preferentially represses transcription and demonstrates an increased affinity for co-repressors, decreased chromatin residence time and lower dependence on FOXA1 binding. We identified a group of ARv7-repressed genes, including the UDP-galactosyltransferase B4GALT1 that are down-regulated during PCa progression and important for CRPC growth. In conclusion, we propose that ARv7 acts as a transcriptional repressor of genes that limit proliferation, a function that should be targeted in CRPC patients.
2018-11-02 | GSE106560 | GEO
Project description:Endocrine therapies in prostate cancer (PCa) treatment block androgen receptor (AR) function, but are palliative as tumors progress to a lethal, castration-resistant state (CRPC). CRPC remains dependent on AR signaling, which can act through the full-length AR (ARfl) or constitutively active splice variants, e.g. ARv7. We show here that both ARfl and ARv7 bind to the same genomic region and heterodimerize in a CRPC cell line model, but regulate distinct transcriptomes. ARv7, unlike ARfl, preferentially represses transcription and demonstrates an increased affinity for co-repressors, decreased chromatin residence time and lower dependence on FOXA1 binding. We identified a group of ARv7-repressed genes, including the UDP-galactosyltransferase B4GALT1 that are down-regulated during PCa progression and important for CRPC growth. In conclusion, we propose that ARv7 acts as a transcriptional repressor of genes that limit proliferation, a function that should be targeted in CRPC patients.
2018-11-02 | GSE106559 | GEO
Project description:ARv7 represses tumor suppressors genes in castration-resistant prostate cancer
| PRJNA417248 | ENA
Project description:ARv7 represses tumor suppressors genes in castration-resistant prostate cancer [ChIP-Seq]
| PRJNA417256 | ENA
Project description:ARv7 represses tumor suppressors genes in castration-resistant prostate cancer [RNA-Seq]
| PRJNA417254 | ENA
Project description:BACKGROUND:The AR-V7 splice variant is a cause of castration-resistant prostate cancer (CRPC). However, testing for the presence of AR-V7 by real-time polymerase chain reaction (RT-PCR) shows AR-V7 positivity in healthy individuals. We hypothesized that the positivity reflects contamination by hematopoietic cells. We tried a novel circulating tumor cell (CTC) enrichment instrument, using Celsee, to clear hematopoietic cells. METHODS:We tested whole blood or Celsee-enriched samples for AR-V7 by RT-PCR, and included samples from 41 CRPC patients undergoing sequential therapy. We evaluated the associations between AR-V7 status and clinical factors. We evaluated factors affecting AR-V7 positivity. RESULTS:AR-V7 positivity was lower in Celsee-enriched than in whole blood specimens. AR-V7 and clinical factors did not predict the therapy effectiveness. We found no significant differences in the effectiveness of enzalutamide/abiraterone (Enz/Abi) upon AR-V7 evaluation. All AR-V7 positive patients had resistance to Enz/Abi. Docetaxel (DTX), cabazitaxel (CBZ), and Radium223 treatment showed no significant difference in the treatment effectiveness, regardless of AR-V7 presence. AR-V7 was more frequently positive than Extent of disease (EOD) 2 in cases with bone metastases. CONCLUSION:Celsee CTC enrichment suppresses AR-V7 false positivity. All AR-V7 positive patients presented resistance to Enz/Abi. DTX, CBZ, and Radium223 were effective and remain treatment options. AR-V7 positivity should progressively appear in patients with advanced bone metastases.
| S-EPMC7151149 | biostudies-literature
Project description:Prostate cancer (PCa) is the second leading cause of cancer-related death in males in the United States. Majority of prostate cancers are originally androgen-dependent and sensitive to androgen-deprivation therapy (ADT), however, most of them eventually relapse and progress into incurable castration-resistant prostate cancer (CRPC). Of note, the activity of androgen receptor (AR) is still required in CRPC stage. The mitotic kinase polo-like kinase 1 (Plk1) is significantly elevated in PCa and its expression correlates with tumor grade. In this study, we assess the effects of Plk1 on AR signaling in both androgen-dependent and androgen-independent PCa cells. We demonstrate that the expression level of Plk1 correlated with tumorigenicity and that inhibition of Plk1 caused reduction of AR expression and AR activity. Furthermore, Plk1 inhibitor BI2536 down-regulated SREBP-dependent expression of enzymes involved in androgen biosynthesis. Of interest, Plk1 level was also reduced when AR activity was inhibited by the antagonist MDV3100. Finally, we show that BI2536 treatment significantly inhibited tumor growth in LNCaP CRPC xenografts. Overall, our data support the concept that Plk1 inhibitor such as BI2536 prevents AR signaling pathway and might have therapeutic potential for CRPC patients.
| S-EPMC4612397 | biostudies-literature
Project description:Enzalutamide and abiraterone have been shown to improve progression-free survival (PFS) and overall survival (OS) in metastatic castration-resistant prostate cancer (mCRPC) patients. Moreover, some patients may not benefit from the inhibition of androgen receptor (AR) activity or, alternatively, may develop secondary resistance. Detection in patients' circulating tumor cells (CTCs) of ARV7, a splicing variant of AR lacking the ligand-binding domain, showed a link with treatment failure. Independent confirmation of the predictive role of CTC status combined with ARV7 detection is, therefore, a priority for extending personalized biomarker-driven treatments to all patients. In this prospective observational study, CTC status and the expression of AR and ARV7 were measured in 37 mCRPC patients, before starting treatment with enzalutamide or abiraterone, by employing commercially available kits. CTC status was positive in 21/37 patients: 46% and 24% of CTC-positive patients were defined as AR- and ARV7-positive, respectively. Kaplan-Meier estimates showed that positivity for each variable was significantly associated with poorer radiological PFS, PSA-PFS, and OS. All considered treatment outcomes worsened when going from CTC-negative to CTC-positive/ARV7-negative to CTC-positive/ARV7-positive patients, both in the global case series and in patients stratified into three groups based on basal PSA levels. Presently, technical approaches appear to be mature for introducing CTC/ARV7 tests in clinical practice.
| S-EPMC6678845 | biostudies-literature
Project description:Despite several treatment options and an initial high response rate to androgen deprivation therapy, the majority of prostate cancers will eventually become castration-resistant in the metastatic stage (mCRPC). Androgen receptor splice variant 7 (ARV7) is one of the best-characterized androgen receptor (AR) variants whose expression in circulating tumor cells (CTCs) has been associated with enzalutamide resistance. ARV7 expression analysis before and during enzalutamide treatment could identify patients requiring alternative systemic therapies. However, a robust test for the assessment of the ARV7 status in patient samples is still missing. Here, we implemented an RT-qPCR-based assay for detection of AR full length (ARFL)/ARV7 expression in CTCs for clinical use. Additionally, as a proof-of-principle, we validated a cohort of 95 mCRPC patients initiating first line treatment with enzalutamide or enzalutamide/metformin within a clinical trial. A total of 95 mCRPC patients were analyzed at baseline of whom 27.3% (26/95) had ARFL+ARV7+, 23.1% (22/95) had ARFL+ARV7-, 23.1% (22/95) had ARFL-ARV7-, and 1.1% (1/95) had ARFL-ARV7+ CTCs. In 11.6% (11/95), no CTCs could be isolated. A total of 25/95 patients had another CTC analysis at progressive disease, of whom 48% (12/25) were ARV7+. Of those, 50% (6/12) were ARV7- and 50% (6/12) were ARV7+ at baseline. Our results show that mRNA analysis of isolated CTCs in mCRPC is feasible and allows for longitudinal endocrine agent response monitoring and hence could contribute to treatment optimization in mCRPC.
| S-EPMC6721786 | biostudies-literature