A Novel Peptide Encoded by circSRCAP Confers Resistance to Enzalutamide by Inhibiting the Ubiquitin-Dependent Degradation of AR-V7 in Castration-Resistant Prostate Cancer
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ABSTRACT:
PROVIDER: PRJNA1101036 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR28709013_1.fastq.gz | Fastqsanger.gz | |||
| SRR28709013_2.fastq.gz | Fastqsanger.gz | |||
| SRR28709014_1.fastq.gz | Fastqsanger.gz | |||
| SRR28709014_2.fastq.gz | Fastqsanger.gz | |||
| SRR28709015_1.fastq.gz | Fastqsanger.gz |
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Project description:Background: The sustained activation of androgen receptor splice variant-7 (AR-V7) is a key factor in the resistance of castration-resistant prostate cancer (CRPC) patients to second-generation anti-androgen (AR) drugs such as enzalutamide (ENZ). The AR/AR-V7 protein is regulated by the E3 ubiquitin ligase STUB1 and a protein complex formed by HSP70. However, the specific mechanism remains elusive. Methods: High-throughput RNA sequencing was employed to detect differentially expressed circular RNAs (circRNAs) in ENZ-resistant and control CRPC cells. The coding potential of circSRCAP was identified through polysome profiling and LC-MS. The function of circSRCAP was validated in vitro and in vivo via gain or loss of function assays. Mechanistic insights were derived from immunoprecipitation analyses. Results: A novel ENZ-resistant circular RNA (circRNA) named circSRCAP has been identified, showing upregulation in ENZ-resistant C4-2B cells (ENZR-C4-2B) and correlation with elevated protein levels of AR-V7. circSRCAP undergoes cleavage into a loop by the splicing factor EIF4A3 and is derived from the nucleus by the RNA helicase DDX39A. Mechanistically, circSRCAP encodes a 75 amino acid peptide, circSRCAP-75aa, which inhibits the ubiquitination of the AR/AR-V7's co-chaperone protein HSP70 by dissociating STUB1, a ubiquitin E3 ligase. This process leads to the upregulation of AR-V7 protein expression, thereby promoting resistance of castration-resistant prostate cancer (CRPC) cells to ENZ. Xenograft tumor models further confirm the role of circSRCAP in CRPC progression and its potential as a therapeutic target for ENZ-resistant CRPC (ENZR-CRPC). Conclusions: circSRCAP presents an epigenetic mechanism that sheds light on the fate determination of AR-V7, offering a promising therapeutic target for the treatment of ENZR-CRPC.
2025-01-29 | GSE264133 | GEO
Project description:Liquid biopsies have demonstrated that the constitutively active androgen receptor splice variant-7 (AR-V7) associates with reduced response and overall survival (OS) from endocrine therapies in castration resistant prostate cancer (CRPC). However, these studies provide little information pertaining to AR-V7 biology and expression in prostate cancer (PC) tissue. Following generation and validation of a novel AR-V7 antibody for immunohistochemistry (IHC); nuclear AR-V7 protein expression was determined for 358 primary prostate samples (358 patients) and 293 metastatic biopsies (194 patients). Associations with disease progression, nuclear AR full length (AR-FL) expression, response to abiraterone and/or enzalutamide, and gene signatures (from three independent cohorts) was determined.
2018-10-19 | GSE118435 | GEO
Project description:The goal of this study was to determine how androgen receptor inhibition alters transcriptional programs in prostate cancer cells. LNCaP prostate cancer cells were grown in 10% charcoal-stripped serum (CSS) supplemented with 0.5 nanomolar dihydrotestosterone (DHT), in CSS without DHT modeling castration, with CSS + DHT but in the presence of 10 micromolar enzalutamide, or in CSS without DHT (castrated) and in the presence of enzalutamide for 72 hours. Analysis shows that androgen receptor target genes are reduced with castration, enzalutamide or the combination of castration + enzalutamide.
2022-05-12 | GSE202755 | GEO
Project description:In order to define the genes responsible for the growth and survival of a human castration-resistant prostate cancer cell line, a short term (doxycycline inducible) knockdown system was developed and utilized. Three independent 22Rv1 cell isolates were derived for each of the following doxycycline-inducible shRNAs (shGFP, shAR3, and shVav3) (AR3 = AR-V7). The cells were grown in androgen depleted conditions, plus or minus doxycycline, for three days. RNA from the 18 samples was then sent to the University of Miami Genetics Core for RNA Integrity Number (RIN) evaluation and microarray analysis. Genes differentially regulated by AR-V7 knock-down or VAV3 knock-down were explored as downstream targets of AR-V7 or VAV3, respectively.
2018-08-16 | GSE104572 | GEO
Project description:The constitutively active androgen receptor (AR) splice variant 7 (AR-V7) plays an important role in the progression of castration-resistant prostate cancer (CRPC). Although biomarker studies established the role of AR-V7 in resistance to AR-targeting therapies, how AR-V7 mediates genomic functions in CRPC remains largely unknown. Using a ChIP-exo approach, we show AR-V7 binds to distinct genomic regions and recognizes a full-length androgen-responsive element in CRPC cells and patient tissues. Remarkably, we find dramatic differences in AR-V7 cistromes across diverse CRPC cells and patient tissues, regulating different target gene sets involved in CRPC progression. Surprisingly, we discover that HoxB13 is universally required for and colocalizes with AR-V7 binding to open chromatin across CRPC genomes. HoxB13 pioneers AR-V7 binding through direct physical interaction, and collaborates with AR-V7 to up-regulate target oncogenes. Transcriptional coregulation by HoxB13 and AR-V7 was further supported by their coexpression in tumors and circulating tumor cells from CRPC patients. Importantly, HoxB13 silencing significantly decreases CRPC growth through inhibition of AR-V7 oncogenic function. These results identify HoxB13 as a pivotal upstream regulator of AR-V7-driven transcriptomes that are often cell context-dependent in CRPC, suggesting that HoxB13 may serve as a therapeutic target for AR-V7-driven prostate tumors.
2018-05-31 | GSE99378 | GEO
Project description:Since its discovery, there has been one central issue of significant clinical relevance related to expression of the truncated androgen receptor splice variant-7 (AR-v7), which lacks the C-terminal ligand binding domain and thus acquires ligand-independent transcriptional activity in castration-resistant prostate cancer (CRPC). That question is whether AR-v7 is simply a marker of enhanced AR transcriptional activity characteristic of resistance to 2nd generation androgen receptor signaling inhibitors (ARSi) like Abiraterone and Enzalutamide, or whether it drives lethal resistance to ARSi. To address this question, the present study utilized 4 independently derived CRPC patient-derived xenografts in which the genetic and phenotypic changes could be followed before and after the development of ARSi resistance. This allowed evaluation of the correlation between acquired resistance to ARSi and changes in the expression levels of full length AR (AR-FL) vs. AR-v7 during this process. The combined results document that elevated expression of AR-FL alone is sufficient for Abiraterone- but not Enzalutamide-resistance. This is true even if AR-FL has a gain-of-function mutation. Furthermore, Enzalutamide-resistance is consistently correlated with the acquisition of AR-v7 expression. To directly test the requirement for AR-v7 expression in ARSi-refractory CRPC, CRISPR-Cas9 knockout of AR-FL and/or AR-v7 in LNCaP-95 cells was performed to evaluate in vitro and in vivo growth responses. These results document that AR-v7 drives Enzalutamide-resistance and focuses the critical need to develop therapeutic options to prevent and/or inhibit AR-v7 driven lethal progression of CRPC.
2020-10-11 | GSE149433 | GEO
Project description:Background. Androgen receptor splice variant-7 (AR-V7) is a truncated form of the androgen receptor protein which lacks the ligand-binding domain, the target of enzalutamide and abiraterone, but remains constitutively active as a transcription factor. We hypothesized that detection of AR-V7 in circulating tumor cells (CTCs) from men with advanced prostate cancer would be associated with resistance to enzalutamide and abiraterone. Methods. We used quantitative reverse-transcription polymerase-chain-reaction (qRT-PCR) to interrogate CTCs for the presence or absence of AR-V7 from prospectively enrolled patients with metastatic castration-resistant prostate cancer initiating treatment with either enzalutamide or abiraterone. We examined associations between AR-V7 status and PSA response rates, PSA-progression-free-survival (PSA-PFS), clinical/radiographic-progression-free-survival (PFS), and overall survival (OS). Multivariable Cox regression analyses were performed to determine the independent effect of AR-V7 status on clinical outcomes. Results. Thirty-one enzalutamide-treated patients and thirty-one abiraterone-treated patients were enrolled, of which 38.7% and 19.4% had detectable AR-V7 from CTCs, respectively. Among men receiving enzalutamide, AR-V7–positive patients had inferior PSA response rates (0% vs 52.6%, P=0.004), PSA-PFS (median: 1.4 vs 6.0 months, P<0.001), PFS (median: 2.1 vs 6.1 months, P<0.001), and OS (median: 5.5 months vs not reached, P=0.002) compared to AR-V7–negative patients. Similarly, among men receiving abiraterone, AR-V7–positive patients had inferior PSA response rates (0% vs 68.0%, P=0.004), PSA-PFS (median: 1.3 months vs not reached, P<0.001), PFS (median: 2.3 months vs not reached, P<0.001), and OS (median: 10.6 months vs not reached, P=0.006). The negative prognostic impact of AR-V7 was maintained after adjusting for full-length-AR expression. Conclusions. Detection of AR-V7 in CTCs from patients with castration-resistant prostate cancer is associated with resistance to enzalutamide and abiraterone. A total of four metastatic castration-resistant prostate tumor samples from four patients were subjected to RNA-seq. Two samples were positive for androgen receptor splice variant 7 and the other two were negative for this variant.
2014-09-03 | E-GEOD-56701 | biostudies-arrayexpress
Project description:The purpose of this study was to characterize the downstream transcriptomic effects of ARVib-mediated degradation of AR/AR-V7, particularly in attenuating AR/AR-V7 target gene expression in prostate cancer cells. Towards this goal, next-generation sequencing (NGS)-based gene expression profiling (RNA-Sequencing; RNA-Seq) was performed on castration-resistant prostate cancer (CRPC) C4-2B MDVR cells that were treated with vehicle control or one of the AR/AR-V7 inhibitors (ARVib), ARVib-7 or ARVib-31.
2021-08-22 | GSE158556 | GEO
Project description:Molecular mechanisms underlying resistance to androgen deprivation therapy (ADT) and, in particular, to antiandrogen Enzalutamide, in treating castration-resistant prostate cancer (CRPC), remain incompletely understood. Through screening >120 CRPC patient samples, we observed 3 expression patterns of androgen receptor (AR) protein: primarily nuclear (nuc-AR), mixed nuclear/cytoplasmic expression (nuc/cyto-AR), and low/no expression (AR-/lo). Xenograft CRPC modeling in 4 models (i.e., LNCaP, VCaP, LAPC4, and LAPC9) recapitulated the 3 AR expression patterns in castration-resistant tumors developed from parental androgen-dependent tumors. Strikingly, although the 3 CRPC models that retained AR expression (LNCaP, VCaP, and LAPC4) responded, to different levels and in different kinetics, to Enzalutamide, the AR-/lo LAPC9 CRPC was completely refractory to Enzalutamide. By combining whole-genome RNA-Seq and biochemical analyses together with experimental combinatorial therapy in the LNCaP and LAPC9 models, we identified BCL-2 as a critical therapeutic target in both AR+/hi and AR-/lo, Enzalutamide-resistant CRPC models.
2018-08-01 | GSE88752 | GEO
Project description:Although AR-V7 has been intensively studied, it remains unclear whether AR-V7 can specifically activate a distinctive transcriptional program from the full-length AR (AR-FL), and whether AR-V7 may play a role in accelerating the metastatic progression of castration-resistant PCa (CRPC). In this study, we hypothesize that AR-V7 can drive a distinct transcription program from AR-FL in CRPC condition. To test this, we used LNCaP model with inducible overexpression of AR-V7 or AR-FL to examine the effects of AR-V7 overexpression or AR-FL overexpression stimulated with DHT for 4 hours on AR-V7 or AR-FL cistromes. We also studied the effects of AR-V7 on cistromes of pioneer factor FOXA1 and active histone marker H3K27ac, and the function of phosphorylation at Ser81 on AR-V7 function in CRPC.
2024-06-05 | GSE221140 | GEO