Transcriptome analyses of AR-V7 and ARv567es
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE221141 | GEO | 2024/06/05
REPOSITORIES: GEO
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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
Project description:Although AR-V7 has been intensively studied, it remains unclear whether AR-V7 and other AR splicing variants 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 performed ATAC-seq using LNCaP model with inducible overexpression of AR-V7 to examine the function of AR-V7. We demonstrated that AR-V7 has “pioneer factor-like” activities to access the androgen-responsive elements (AREs) located at compact chromatin regions. More importantly, we found that SOX9, a critical metastasis driver gene, was a direct target and downstream effector of AR-V7, and its protein expression was dramatically upregulated at AR-V7-induced bone lesions.
2024-06-05 | GSE221137 | 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:CRPC remains AR dependent. There are multiple mechanisms for reactivation of AR including expression of constitutively active AR splices variant AR-V7 (AR3). Earlier studies suggest that though the variants regulate many of the same genes as AR, they also have unique targets. Another argument is that the variant is a “weak” AR. We have used an LNCaP cell line that expresses AR-V7 in response to doxycycline to compare DNA interactions of the two isoforms and to identify differential regulation of target genes. ChIP-exo method was used to map AR and AR-V7 interaction with DNA in LNCaP engineered cell line (LNCaP AR-V7) at single base resolution.
2021-07-07 | GSE143906 | GEO
Project description:To elucidate the AR-V7 role, we performed ChIP-seq on H3K4me1, H3K4me3, H3K27ac, and AR antibody recognizing the N-terminus of AR and AR splice variants (AR-Vs) using LNCaP and LNCaP95 cells. We showed 399 AR-V7 targeted regions in LNCaP95, most of the AR-V7 target regions could be commonly activated by hormone stimulated AR. However, 22 regions were identified as AR-V7 specific regions. In addition, we show here that AR-V7 can transcript in the ligand independent manner in LNCaP95, unlike LNCaP. We identified the AR-V7 target gene contributing to the CRPC progression.
2020-11-02 | GSE122922 | GEO
Project description:CRPC remains AR dependent. There are multiple mechanisms for reactivation of AR including expression of constitutively active AR splices variant AR-V7 (AR3). Earlier studies suggest that though the variants regulate many of the same genes as AR, they also have unique targets. Another argument is that the variant is a “weak” AR. We have used an LNCaP cell line that expresses AR-V7 in response to doxycycline (LNCaP AR-V7) to compare the activities of the two isoforms and to identify differential regulation of target genes. We also used VCaP cell line that expresses AR-V7 in response to doxycycline (VCaP AR-V7) to validate the activities of the two isoforms in an alternative prostate cancer cell line. The transcriptomes for AR and AR-V7 in these cell lines were identified using RNA-Seq.
2021-01-21 | GSE143905 | GEO
Project description:In castration-resistant prostate cancer (CRPC), clinical response to androgen receptor (AR) antagonists is limited mainly due to AR-variants expression and restored AR signaling. The metabolite spermine is most abundant in prostate and it decreases as prostate cancer progresses, but its functions remain poorly understood. Here, we show spermine inhibits full-length androgen receptor (AR-FL) and androgen receptor splice variant 7 (AR-V7) signaling and suppresses CRPC cell proliferation by directly binding and inhibiting protein arginine methyltransferase PRMT1. Spermine reduces H4R3me2a modification at the AR locus and suppresses AR binding as well as H3K27ac modification levels at AR target genes. Spermine supplementation restrains CRPC growth in vivo. PRMT1 inhibition also suppresses AR-FL and AR-V7 signaling and reduces CRPC growth. Collectively, we demonstrate spermine as an anticancer metabolite by inhibiting PRMT1 to transcriptionally inhibit AR-FL and AR-V7 signaling in CRPC, and we indicate spermine and PRMT1 inhibition as powerful strategies overcoming limitations of current AR-based therapies in CRPC.
2023-10-11 | MTBLS8034 | MetaboLights
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:Continued androgen receptor (AR) signaling is an established mechanism underlying castration-resistant prostate cancer (CRPC), and suppression of AR signaling remains a therapeutic goal of CRPC therapy. Constitutively active androgen receptor splicing variants (AR-Vs) lack the AR ligand-binding domain (AR-LBD), the intended target of androgen deprivation therapies (ADT) including new CRPC therapies such as abiraterone and MDV3100. While the canonical full-length AR (AR-FL) and AR-Vs are both increased in CRPC, their expression regulation, associated transcriptional programs, functional relationships, and respective roles in mediating responses to endocrine therapies have not been dissected. In this study, we show that suppression of canonical AR-FL signaling by targeting AR-LBD leads to increased AR-V expression in two cell line models of CRPC. Importantly, treatment-induced AR-Vs activate a distinct expression signature enriched for cell cycle genes without requiring the presence of AR-FL. Conversely, activation of AR-FL signaling suppresses the AR-V signature but activates expression programs mainly associated with macromolecular synthesis, metabolism, and differentiation. In prostate cancer cells and CRPC xenografts treated with MDV3100 and abiraterone, increased expression of two constitutively active AR-Vs, AR-V7 and ARV567ES, but not AR-FL, parallels increased expression of the AR-driven cell cycle gene UBE2C. In addition, protein expression of AR-V7, but not AR-FL, is positively correlated with UBE2C in clinical CRPC specimens. The cumulative in vitro and in vivo evidence support an adaptive shift toward AR-V-mediated signaling in at least a subset of CRPC tumors as the AR-LBD is rendered inactive, suggesting an important mechanism contributing to drug resistance to CRPC therapies. LNCaP cells lacking AR-V were transfected with AR-V7 with or without androgen stimulation of AR-FL (4 conditions); LNCaP95 cells expressing AR-Vs were treated with control siRNA or siRNA trageting AR-LBD or AR-DBD, with or without androgen stimulation of AR-FL (6 conditions); VCaP cells expressing AR-Vs in the presence of androgen were treated with control siRNA, siRNA trageting AR-LBD, DMSO or MDV3100 to inhibit AR-FL (4 conditions). Total 14 arrays with no replicates.
2012-03-17 | E-GEOD-36549 | biostudies-arrayexpress
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