Analysis of active enhancers and direct androgen receptor target genes in VCaP prostate cancer cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE84432 | GEO | 2016/10/06
SECONDARY ACCESSION(S): PRJNA329137
REPOSITORIES: GEO
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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: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:Androgen receptor (AR) is reactivated in castration resistant prostate cancer (CRPC) through mechanisms including marked increases in AR gene expression. We identify an enhancer in the AR second intron contributing to increased AR expression at low androgen levels in CRPC. Moreover, at increased androgen levels the AR binds this site and represses AR gene expression through recruitment of lysine specific demethylase 1 (LSD1) and H3K4me1,2 demethylation. AR similarly represses expression of multiple genes mediating androgen synthesis, DNA synthesis and proliferation, while stimulating genes mediating lipid and protein biosynthesis. Androgen levels in CRPC appear adequate to stimulate AR activity on enhancer elements, but not on suppressor elements, resulting in increased expression of AR and AR repressed genes that contribute to cellular proliferation. Custom Agilent 44K whole human genome expression oligonucleotide microarrays were used to profile pre-castrated androgen dependent, 4d-post-castrated, and relapsed castration resistant VCaP xenograft tumors in 3 mice. Total RNA was isolated and amplified prior to hybridization against a common reference pool of prostate tumor cell lines.
2011-08-15 | E-GEOD-31410 | biostudies-arrayexpress
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:Resistance to androgen deprivation therapies and increased androgen receptor (AR) activity are major drivers of castration-resistant prostate cancer (CRPC). Prior work has focused on targeting AR directly; however, the identification and targeting of co-activators of AR signaling remains an underexplored area. Here we demonstrate that the MLL (mixed-lineage leukemia) complex, a well-known contributor in MLL-fusion-positive leukemia, acts as a co-activator of AR signaling. AR interacts with the MLL complex via its subunit, menin. Small molecule inhibition of the menin-MLL interaction blocks AR signaling and inhibits tumor growth in vivo. Furthermore, we find that menin is up-regulated in CRPC and high expression correlates with poor overall survival. Our study identifies the MLL complex as a co-activator of AR that can be targeted in advanced prostate cancer. ASH2L / Menin / MLL1 were knocked down using shRNA /siRNA in two prostate cancer cell lines, VCaP and LNCaP.
2015-03-02 | E-GEOD-60836 | biostudies-arrayexpress
Project description:The androgen receptor (AR) is a ligand-inducible transcription factor that mediates androgen action in target tissues. Upon ligand binding, the AR binds to thousands of genomic loci and activates a cell-type specific gene program. Prostate cancer growth and progression depend on androgen-induced AR signalling. Treatment of advanced prostate cancer through medical or surgical castration leads to initial response and durable remission, but resistance inevitably develops. In castration-resistant prostate cancer (CRPC), AR activity remains critical for tumor growth despite androgen deprivation. While previous studies have focused on ligand-dependent AR signalling, in this study we explore AR function under the androgen-deprived conditions characteristic of CRPC. Our data demonstrate that the AR persistently occupies a distinct set of genomic loci after androgen deprivation in CRPC. These androgen-independent AR occupied regions have constitutively open chromatin structures that lack the canonical androgen response element and are independent of FoxA1, a transcription factor involved in ligand-dependent AR targeting. Many AR binding events occur at proximal promoters, which can act as enhancers to augment transcriptional activities of other promoters through DNA looping. We further show that androgen-independent AR binding directs a distinct gene expression program in CRPC, which is necessary for the growth of CRPC after androgen withdrawal. LNCaP, C4-2B, or 22RV1 cells were cultured in hormone-free media for 3 days and then treated with ethanol vehicle or DHT (10nM) for 4h or 16h prior to ChIP-seq or RNA-seq assays. For siRNA transfection, cells were transfected with AR siRNA or control siRNA for 3 days prior to RNA-seq assays.
2012-10-02 | E-GEOD-40050 | biostudies-arrayexpress
Project description:In this study we functionally quantified the enhancer activity of all clinical ARBS. We demonstrated that only 7% of ARBS demonstrate androgen-dependent enhancer activation, while 11% have enhancer activity independent of AR binding. Almost all of these AR enhancers have not been previously studied. Surprisingly the vast majority of ARBS (81%) do not have significant enhancer activity. This in vitro annotation strongly correlated to clinical PCa samples. Integrating long-range chromatin interactome and transcriptomic data, we found androgen inducible enhancers were significantly more enriched to serve as anchors for gene looping and acted as a ?hub? to activate AR-regulated genes. To characterize the mechanism of AR enhancers we developed a deep neural network that can successfully predict active enhancers and identify key features for active enhancers. Finally, combining these results with whole genome sequencing of primary and metastatic PCa, we identified and characterized non-coding somatic SNVs that significantly impacted AR enhancer activity of a critical tumour suppressor.
2021-03-28 | GSE154632 | GEO
Project description:In this study we functionally quantified the enhancer activity of all clinical ARBS. We demonstrated that only 7% of ARBS demonstrate androgen-dependent enhancer activation, while 11% have enhancer activity independent of AR binding. Almost all of these AR enhancers have not been previously studied. Surprisingly the vast majority of ARBS (81%) do not have significant enhancer activity. This in vitro annotation strongly correlated to clinical PCa samples. Integrating long-range chromatin interactome and transcriptomic data, we found androgen inducible enhancers were significantly more enriched to serve as anchors for gene looping and acted as a ‘hub’ to activate AR-regulated genes. To characterize the mechanism of AR enhancers we developed a deep neural network that can successfully predict active enhancers and identify key features for active enhancers. Finally, combining these results with whole genome sequencing of primary and metastatic PCa, we identified and characterized non-coding somatic SNVs that significantly impacted AR enhancer activity of a critical tumour suppressor.
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Project description:The androgen receptor (AR) is a ligand-inducible transcription factor that mediates androgen action in target tissues. Upon ligand binding, the AR binds to thousands of genomic loci and activates a cell-type specific gene program. Prostate cancer growth and progression depend on androgen-induced AR signalling. Treatment of advanced prostate cancer through medical or surgical castration leads to initial response and durable remission, but resistance inevitably develops. In castration-resistant prostate cancer (CRPC), AR activity remains critical for tumor growth despite androgen deprivation. While previous studies have focused on ligand-dependent AR signalling, in this study we explore AR function under the androgen-deprived conditions characteristic of CRPC. Our data demonstrate that the AR persistently occupies a distinct set of genomic loci after androgen deprivation in CRPC. These androgen-independent AR occupied regions have constitutively open chromatin structures that lack the canonical androgen response element and are independent of FoxA1, a transcription factor involved in ligand-dependent AR targeting. Many AR binding events occur at proximal promoters, which can act as enhancers to augment transcriptional activities of other promoters through DNA looping. We further show that androgen-independent AR binding directs a distinct gene expression program in CRPC, which is necessary for the growth of CRPC after androgen withdrawal.
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2016-02-12 | E-GEOD-55031 | biostudies-arrayexpress