LNCaP LSD1 knockdown and SP-2509 treatment ChIP-seq data
ABSTRACT: LSD1 (also known as KDM1A) is a histone demethylase and a key regulator of gene expression in embryonic stem cells and cancer.1,2 LSD1 was initially identified as a transcriptional repressor via its demethylation of active histone H3 marks (di-methyl lysine 4 [2MK4]).1 In prostate cancer, specifically, LSD1 also co-localizes with the AR and demethylates repressive 2MK9 histone marks from androgen-responsive AR target genes, facilitating androgen-mediated induction of AR-regulated gene expression and androgen-induced proliferation in androgen-dependent cancers. We report here that the LSD1 protein is universally upregulated in human CRPC and promotes survival of CRPC cell lines. This effect is explained in part by LSD1-induced activation of cell cycle and embryonic stem cell gene sets—gene sets enriched in transcriptomal studies of lethal human tumors. Importantly, despite the fact that many of these genes are direct LSD1 targets, we did not observe histone methylation changes at the LSD1-bound regions, demonstrating non-canonical histone demethylation-independent mechanisms of gene regulation. This ChIP-seq dataset included H3K4me2 and H3K9me2 ChIP-seq data for siRNA target against LSD1 and non-targeting control, as well as SP2509 inhibition of LSD1 and mock treatment 4 conditions: siRNA against LSD1, siRNA against luciferase (non-targeting control); SP2509 inhibition of LSD1, mock treatment. There are 2 replicates per condition.
Project description:Lysine Specific Demethylase 1 (LSD1, KDM1A) functions as a transcriptional corepressor through demethylation of histone 3 lysine 4 (H3K4), but has coactivator function on some genes through unclear mechanisms. We show that LSD1, interacting with CoREST, associates with and coactivates androgen receptor (AR) on a large fraction of androgen-stimulated genes. A subset of these AR/LSD1-associated enhancer sites have histone 3 threonine 6 phosphorylation (H3T6ph), and these sites are further enriched for androgen-stimulated genes. Significantly, despite its coactivator activity, LSD1 still mediates H3K4me2 demethylation at these androgen-stimulated enhancers. FOXA1 is also associated with LSD1 at AR regulated enhancer sites, and a FOXA1 interaction with LSD1 enhances binding of both proteins at these sites. These findings show LSD1 functions broadly as a regulator of AR function, that it maintains a transcriptional repression function at AR-regulated enhancers through H3K4 demethylation, and has a distinct AR-linked coactivator function mediated by demethylation of other substrates. Determine the role of LSD1 in androgen signaling.
Project description:LSD1 (also known as KDM1A) is a histone demethylase and a key regulator of gene expression in embryonic stem cells and cancer.1,2 LSD1 was initially identified as a transcriptional repressor via its demethylation of active histone H3 marks (di-methyl lysine 4 [2MK4]).1 In prostate cancer, specifically, LSD1 also co-localizes with the AR and demethylates repressive 2MK9 histone marks from androgen-responsive AR target genes, facilitating androgen-mediated induction of AR-regulated gene expression and androgen-induced proliferation in androgen-dependent cancers.3,4 Recently, it was shown that treatment with high doses of androgens (e.g.10-fold higher doses than those required for induction of expression of androgen-activated genes such as PSA) recruits LSD1 and AR to an enhancer within the AR; this AR and LSD1 recruitment represses AR transcription.5 Thus, LSD1 appears to play a role in mediating both the proliferative and repressive phases of the biphasic androgen dose-response curve. For these reasons, we hypothesized that LSD1 might be important for maintenance of AR signaling in castration-resistant prostate cancer (CRPC) tumors. However, in this report, we describe a distinct role of LSD1 as a driver of proliferation and survival of prostate cancer cells, including CRPC cells, irrespective of androgens or even AR expression. Specifically, LSD1 activates expression of cell cycle, mitosis, and embryonic stem cell maintenance pathways that are enriched in lethal prostate cancers – pathways not activated by androgens. Finally, we observe that treatment with a new LSD1 inhibitor potently and specifically suppresses LSD1 function and suppresses CRPC growth and survival in vitro and in vivo. Our data place LSD1 as a key driver of androgen-independent survival in lethal prostate cancers and demonstrate the potential of LSD1-directed therapies in the near-term. The enclosed files are from microarrays experiments after suppressing LSD1 with RNAi or stimulating cells with the androgen agonist dihydrotestosterone (DHT).
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.
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.
Project description:The mainstay treatment for men with metastatic prostate cancer is androgen deprivation therapy (ADT), which inhibits androgen biosynthesis and/or binding of ligand to the androgen receptor (AR). Most men respond to ADT, but all subsequently develop resistance and progression to incurable and lethal castration-resistant prostate cancer (CRPC). CRPC generally remains driven by the AR: therefore, the development of novel AR-targeted therapies, as well as elucidating therapy-driven changes to the AR signalling axis that mediate resistance, remain priorities for the field. Using a novel and powerful proteomic technique, rapid immunoprecipitation of endogenous proteins (RIME), we have identified a new AR binding protein, the transcription factor Grainyhead-like 2 (GRHL2), and shown that it plays an essential, multifaceted role in signalling by the canonical AR and by constitutively active truncated AR variants (ARVs). GRHL2 is necessary for the maintenance of AR/ARV expression in multiple prostate cancer model systems, co-localises with AR at specific sites on chromatin to enhance the androgen-regulated transcriptional program, and is required for optimal prostate cancer growth. Interestingly, we found that GRHL2 is itself an AR/ARV-regulated gene, creating a positive feed-forward loop between the two factors. The GRHL2 gene is frequently amplified and upregulated in CRPC, thereby potentially enabling further amplification AR signalling in the drug-resistant setting. In summary, this study has identified a critical new AR coregulator and potential therapeutic target in prostate cancer. ChIP-seq for GRHL2 and AR in LNCaP cells
Project description:The mainstay treatment for men with metastatic prostate cancer is androgen deprivation therapy (ADT), which inhibits androgen biosynthesis and/or binding of ligand to the androgen receptor (AR). Most men respond to ADT, but all subsequently develop resistance and progression to incurable and lethal castration-resistant prostate cancer (CRPC). CRPC generally remains driven by the AR: therefore, the development of novel AR-targeted therapies, as well as elucidating therapy-driven changes to the AR signalling axis that mediate resistance, remain priorities for the field. Using a novel and powerful proteomic technique, rapid immunoprecipitation of endogenous proteins (RIME), we have identified a new AR binding protein, the transcription factor Grainyhead-like 2 (GRHL2), and shown that it plays an essential, multifaceted role in signalling by the canonical AR and by constitutively active truncated AR variants (ARVs). GRHL2 is necessary for the maintenance of AR/ARV expression in multiple prostate cancer model systems, co-localises with AR at specific sites on chromatin to enhance the androgen-regulated transcriptional program, and is required for optimal prostate cancer growth. Interestingly, we found that GRHL2 is itself an AR/ARV-regulated gene, creating a positive feed-forward loop between the two factors. The GRHL2 gene is frequently amplified and upregulated in CRPC, thereby potentially enabling further amplification AR signalling in the drug-resistant setting. In summary, this study has identified a critical new AR coregulator and potential therapeutic target in prostate cancer. RNA-seq following GRHL2 knockdown in LNCaP cells
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.
Project description:Background: Castration-resistant prostate cancer (CRPC) represents a therapeutic challenge for current medications. Methods: In order to explore the molecular mechanisms involved in CRPC progression and to identify new therapeutic targets, we analyzed a unique sample set of 11 castration-resistant prostate cancers and 7 advanced tumors by array-CGH and gene expression microarrays. The genome-wide DNA and RNA data were integrated to identify genes whose overexpression was driven by their amplification. To assess the functional role of these genes, their expression was analyzed in a transcriptional dataset of 329 clinical prostate cancers and the corresponding gene products were silenced using RNA interference in prostate cancer cells. Results: Six recurrent genetic targets were identified in the CRPCs; ATP1B1, AR, FAM110B, LAS1L, MYC and YIPF6. In addition to AR and MYC, FAM110B emerged as a potential key gene involved in CRPC progression in a subset of the tumors. FAM110B was able to regulate AR signaling in prostate cancer cells and FAM110B itself was regulated by androgens. FAM110B siRNA inhibited the growth of prostate cancer cells in vitro, and this effect was substantially enhanced in androgen deficient conditions. Ectopic FAM110B expression in non-cancerous epithelial prostate cells induced aneuploidy and impaired antigen presentation. Conclusions: The DNA / RNA gene outlier detection combined with siRNA cell proliferation assay identified FAM110B as a potential growth promoting key gene for CRPC. FAM110B appears to have a key role in the androgen signaling and progression of CRPC impacting multiple cancer hallmarks and therefore highlighting a potential therapeutic target.  Gene expression levels from 13 samples were measured using Affymetrix GeneChip Human Genome U133 plus 2.0 arrays. Sample processing and labeling were done according to the protocol provided by Affymetrix. Three micrograms of total RNA from each sample was used for the initial one-cycle cDNA synthesis. Arrays were scanned immediately after staining using a GeneChip scanner (Affymetrix).  aCGH was performed from 18 prostate cancer samples using 44K arrays by Agilent Technologies. Male genomic DNA (catalog number G1471, Promega, Madison, WI) was used as reference in all hybridizations.  Gene expression changes following FAM110B silencing in LNCaP prostate cancer cells (48 h: pooled FAM110B siRNA vs. Scrambled siRNA; 72 h: FAM110B siRNAs 1 - 4 and pooled siRNA vs. Scrambled siRNA) and ectopic FAM110B over-expression in both RWPE-1 and LNCaP cells (FAM110B-pEGFP vs. pEGFP, 48 h) were analyzed. The raw data for these Samples are available in the 'GSE28403_LNCaP_RWPE-1_Raw_Data.txt' file, which is linked to this record as a supplementary file.
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.
Project description:The development and progression of castrate resistant prostate cancer (CRPC), a lethal disease, is thought to be driven by multiple events. A hallmark of CRPC is the ability to evade the cytotoxic effects of anti-androgen therapy. Importantly, persistent androgen receptor (AR) signalling is thought to play a principal role in maintaining CRPC. The precise molecular alterations driving this condition, however, are not clearly understood. Our previous studies identified specific metabolic alterations associated with localized prostate cancer (PCa) and CRPC, implicating metabolic re-programming in disease progression. Building on these findings, using a novel network-based integromics approach, here we show distinct alterations in the Hexosamine Biosynthetic Pathway (HBP) to be critical for sustaining the castrate resistant state. We found expression of the HBP enzyme glucosamine-phosphate N-acetyltransferase 1 (GNPNAT1) was regulated by androgens and elevated in androgen dependent (AD) PCa while relatively diminished in CRPC possessing either full length AR (AR-FL) or the spliced V7 variant (AR-V7). Genetic loss of function experiments for GNPNAT1 in CRPC-like cells led to increased proliferation and aggressiveness, both, in vitro and in vivo. This was mediated by specific cell cycle genes regulated by the PI3K-AKT pathway activating either AR in cells with AR-FL or SP1-ChREBP (carbohydrate response element binding protein) in cells containing AR-V7. Strikingly, addition of HBP metabolite UDP-N-acetylglucosamine (UDP) to CRPC-like cells reduced the expression of cell cycle genes and attenuated tumor cell proliferation, both in vitro and in vivo. Furthermore, addition of UDP sensitized CRPC-like cells, inclusive of those possessing AR-V7, to enzalutamide, demonstrating the therapeutic value of targeting altered metabolic pathways in lethal PCa. We anticipate that our findings will motivate the development of novel metabolic therapeutic strategies that complement existing treatments for men with lethal prostate cancer We used microarray analysis to determine key molecular alterations associated with inhibition of HBP pathway in CRPC by knocking down GNPNAT1 transcript level using lentiviral particle bearing shRNA in 22Rv1 and LNCaP-ABL cells GNPNAT1 expression was knockdown in two independent prostate cancer cells, 22Rv1 and LNCaP-ABL