Polycomb-mediated deactivation of AR-feedback loop leads to castration-resistant prostate cancer [ChIP-seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE79357 | GEO | 2017/02/19
SECONDARY ACCESSION(S): PRJNA315572
REPOSITORIES: GEO
Similar Datasets
Project description:Castration-resistant prostate cancer (CRPC) is a lethal disease, often characterized by aberrant androgen receptor (AR) activation independently of androgen. We have previously reported that AR can directly repress the expression of many target genes, one of which is NOV/CCN3. Here we show that NOV, primarily localized in the cytoplasm, physically interacts with AR at its Nterminus and sequesters AR and AR variants in the cytoplasm, thereby reducing AR chromatintargeting. This negative feedback loop, however, is disrupted in CRPC due to epigenetic silencing of NOV by the Polycomb group protein EZH2, rendering AR transcriptional activities and drug-resistant prostate cancer progression. Our findings thus suggest a working model wherein AR-repressed genes critically prevent CRPC through negative feedback loops inhibiting AR signaling.
2017-02-19 | GSE79356 | GEO
Project description:CD95 was found to be important for both the formation of CSCs and their maintenance. Using a stable isotope labeling by amino acids in cell culture (SILAC) analysis we have now identified STAT1 as a critical gene that mediates the CSC-driving activity of CD95. We report that chronic stimulation of CD95 by either agonist antibodies, soluble CD95L or stably expressed membrane CD95L causes both serine and tyrosine phosphorylation of STAT1 and activation of STAT1 regulated genes. The genes most significantly induced were part of an interferon (IFN)-related DNA damage resistance signature (IRDS) recently identified in a radiation resistant squamous cell carcinoma cell line Nu61 when compared to parental SCC61 cells. The IRDS was found to strongly correlate with therapy resistance (chemotherapy and radiation) in multiple cancer cells as well as in 5 human primary cancers. We now report that CD95 stimulation of breast cancer cell lines or the SCC61 cells induces the upregulation of Type I IFNs that bind to both Type I receptors IFNAR1 and IFNR2 resulting in activation of JAK kinases, activation of STAT1 and induction of a number of STAT1-regulated genes. This process can be inhibited by active caspases. Consequently, we identified Type I IFNs as drivers of cancer stemness. Knockdown of STAT1 using either siRNAs or shRNAs, or deleting two independent sites in the STAT1 gene in MCF-7 cells using the CRIPSR/Cas9 gene editing system resulted in a loss of the ability of CD95 to increase stemness. This identifies STAT1 as a critical mediator of the CSCs-inducing activity of CD95. androgen receptor (AR) activation independently of androgen. We have previously reported that AR can directly repress the expression of many target genes, one of which is NOV/CCN3. Here we show that NOV, primarily localized in the cytoplasm, physically interacts with AR at its Nterminus and sequesters AR and AR variants in the cytoplasm, thereby reducing AR chromatintargeting. This negative feedback loop, however, is disrupted in CRPC due to epigenetic silencing of NOV by the Polycomb group protein EZH2, rendering AR transcriptional activities and drug-resistant prostate cancer progression. Our findings thus suggest a working model wherein AR-repressed genes critically prevent CRPC through negative feedback loops inhibiting AR signaling.
2017-02-16 | GSE81859 | 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:The spliced variant forms of androgen receptor (AR-Vs) have been identified recently in castration-resistant prostate cancer (CRPC) cell lines and clinical samples. Here we identified the cistrome and transcriptome landscape of AR-Vs in CRPC cell lines and determine the clinical significance of AR variants regulated gene.The AR variants binding sites can be identified in 22Rv1 cell line in the absence of androgen. Knocking down full-length AR (AR-FL) doesn't affect AR-Vs binding sites in genome-wide. A set of genes were identified to be regulated uniquely by AR-Vs, but not by AR-FL in androgen-depleted condition. Integrated analysis showed that some genes may be modulated by AR-Vs directly. Unsupervised clustering analysis demonstrated that AR variants gene signature can separate not only the benign and malignant prostate tissue, but also the localized prostate cancer and metastatic CRPC specimens. Some genes modulated uniquely by AR variants were also identified to correlate with the Gleason Pattern of prostate cancer and PSA failure. We conclude that AR spliced variants bind to DNA independent of full-length AR, and can modulate a unique set of genes which is not regulated by full-length AR in the absence of androgen. AR variants gene signature correlate with CRPC and prostate cnacer disease progress. Androgen receptor (AR) binding sites in human prostate cancer 22Rv1 cell lines were studied using ChIP-seq. ChIP enriched and input DNA were sequenced using Illumina HiSeq 2000.
2014-09-10 | E-GEOD-58478 | biostudies-arrayexpress
Project description:Prostate cancer is the most commonly diagnosed and second-most lethal cancer among men in the United States. The vast majority of prostate cancer deaths are due to castration-resistant prostate cancer (CRPC) â?? the lethal form of the disease that has progressed despite therapies that interfere with activation of androgen receptor (AR) signaling. One emergent resistance mechanism to medical castration is synthesis of intratumoral androgens that activate the AR. This insight led to the development of the AR antagonist enzalutamide. However, resistance to enzalutamide invariably develops, and disease progression is nearly universal. One mechanism of resistance to enzalutamide is an F877L mutation in the AR ligand-binding domain that can convert enzalutamide to an agonist of AR activity. However, mechanisms that contribute to the agonist switch had not been fully clarified, and there were no therapies to block AR F877L. Using cell line models of castration-resistant prostate cancer (CRPC), we determined that cellular androgen content influences enzalutamide agonism of mutant F877L AR. Further, enzalutamide treatment of AR F877L-expressing cell lines recapitulated the effects of androgen activation of F877L AR or wild-type AR. Because the BET bromodomain inhibitor JQ-1 was previously shown to block androgen activation of wild-type AR, we tested JQ-1 in AR F877L-expressing CRPC models. We determined that JQ-1 suppressed androgen or enzalutamide activation of mutant F877L AR and suppressed growth of mutant F877L AR CRPC tumors in vivo, demonstrating a new strategy to treat tumors harboring this mutation. RNA-seq profiles of prostate cancer cell lines to understand gene expression associated with enzalutamide treatment
2016-06-10 | E-GEOD-69896 | biostudies-arrayexpress
Project description:Androgen receptor (AR) signaling remains the key therapeutic target in the management of hormone-naïve advanced prostate cancer (PCa) and castration-resistant PCa (CRPC). Recently, landmark molecular features have been reported for CRPC, including the expression of constitutively active AR variants that lack the ligand-binding domain. Besides their role in CRPC, AR variants lead to the expression of genes involved in tumor progression. However, little is known about the specificity of their mode of action compared with that of wild-type AR (AR-WT). We performed AR transcriptome analyses in an androgen-dependent PCa cell line as well as cross-analyses with publicly available RNA-seq dataset and established that transcriptional repression capacity that was marked for AR-WT was pathologically lost by AR variants. Functional enrichment analyses allowed us to associate AR-WT repressive function to a panel of genes involved in cell adhesion and epithelial-to-mesenchymal transition. So, we postulate that a less documented AR-WT normal function in prostate epithelial cells could be the repression of a panel of genes linked to cell plasticity, and that this repressive function could be pathologically abrogated by AR variants in PCA.
2022-10-14 | PXD029454 | Pride
Project description:Androgen receptor (AR) signaling remains the key therapeutic target in the management of hormone-naïve advanced prostate cancer (PCa) and castration-resistant PCa (CRPC). Recently, landmark molecular features have been reported for CRPC, including the expression of constitutively active AR variants that lack the ligand-binding domain. Besides their role in CRPC, AR variants lead to the expression of genes involved in tumor progression. However, little is known about the specificity of their mode of action compared with that of wild-type AR (AR-WT). We performed AR transcriptome analyses in an androgen-dependent PCa cell line as well as cross-analyses with publicly available RNA-seq dataset and established that transcriptional repression capacity that was marked for AR-WT was pathologically lost by AR variants. Functional enrichment analyses allowed us to associate AR-WT repressive function to a panel of genes involved in cell adhesion and epithelial-to-mesenchymal transition. So, we postulate that a less documented AR-WT normal function in prostate epithelial cells could be the repression of a panel of genes linked to cell plasticity, and that this repressive function could be pathologically abrogated by AR variants in PCA.
2022-10-13 | PXD029520 | Pride
Project description:Prostate cancer is the most common cancer in men and androgen receptor (AR) downstream signalings promote prostate cancer progression. Although androgen deprivation therapy is effective for treating prostate cancer, most of tumors relapsed as castration-resistant prostate cancer (CRPC). We performed ChIP-seq analysis to investigate the role of AR-associated factors and histone modifications using CRPC model cells, 22Rv1.
2019-04-01 | GSE123565 | GEO
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