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.
Project description:<p>Molecularly-targeted therapies for advanced prostate cancer include castration modalities that suppress ligand-dependent transcriptional activity of the androgen receptor (AR). However, persistent AR signaling undermines therapeutic efficacy and promotes progression to lethal castration-resistant prostate cancer (CRPC), even when patients are treated with potent second-generation AR-targeted therapies abiraterone and enzalutamide. Here we define diverse AR genomic structural rearrangements (AR-GSRs) as a class of molecular alterations occurring in one third of CRPC-stage tumors. AR-GSRs occur in the context of copy-neutral and amplified AR and display heterogeneity in breakpoint location, rearrangement class, and sub-clonal enrichment in tumors within and between patients. Despite this heterogeneity, one common outcome in tumors with high sub-clonal enrichment of AR-GSRs is outlier expression of diverse AR variant species lacking the ligand binding domain and possessing ligand-independent transcriptional activity. Collectively, these findings reveal AR-GSRs as important drivers of persistent AR signaling in CRPC.</p>
Project description:Androgen Receptor (AR) variants (AR-V) drive prostate cancer (PCa) resistance to first and second-generation therapies targeting endocrine regulation of AR. To understand the sets of genomic targets of full-length AR vs. AR-Vs, we conducted genome-wide ChIP-seq using isogenic pairs of genome engineering cell lines expressing either ARv567es (R1-D567) or full-length AR (R1-AD1). Our data demonstrate that androgen-activated full-length AR and AR-Vs both bind to similar genomic targets, which are enriched for high affinity androgen response elements (AREs). Overall, this study demonstrates that AR-Vs restore the broad AR cistrome that is otherwise lost during endocrine-targeted therapy.
Project description:Androgen receptor (AR) is a key player in prostate cancer development and progression. Here we applied immunoprecipitation mass spectrometry of endogenous AR in LNCaP cells to identify components of the AR transcriptional complex. In total, 66 known and novel AR interactors were identified in the presence of synthetic androgen, most of which were critical for AR-driven prostate cancer cell proliferation. A subset of AR interactors required for LNCaP proliferation were profiled using chromatin immunoprecipitation assays followed by sequencing, identifying distinct genomic subcomplexes of AR interaction partners. Interestingly, three major subgroups of genomic subcomplexes were identified, where selective gain of function for AR genomic action in tumorigenesis was found, dictated by FOXA1 and HOXB13. In summary, by combining proteomic and genomic approaches we reveal subclasses of AR transcriptional complexes, differentiating normal AR behavior from the oncogenic state. In this process, the expression of AR interactors has key roles by reprogramming the AR cistrome and interactome in a genomic location-specific manner.
Project description:Recurrent point mutations in SPOP define a distinct molecular subclass of prostate cancer. Here, we describe the first mouse model showing that mutant SPOP drives prostate tumorigenesis in vivo. Conditional expression of mutant SPOP in the prostate dramatically altered phenotypes in the setting of Pten loss, with early neoplastic lesions (high-grade prostatic intraepithelial neoplasia) with striking nuclear atypia, and invasive poorly differentiated carcinoma. In mouse prostate organoids, mutant SPOP drove increased proliferation and a transcriptional signature consistent with human prostate cancer. Using these models and human prostate cancer samples, we show that SPOP mutation activates both PI3K/mTOR and androgen receptor (AR) signaling, effectively uncoupling the normal negative feedback between these two pathways. Associated RNA-seq data deposited in GEO: GSE94839.
Project description:Castration resistant prostate cancer (CRPC) is a lethal disease1-4. Aberrant activation of the androgen receptor (AR) becomes a central mechanism contributing to the resistance of endocrine therapies2,3. Here we demonstrate that non-coding RNAs transcribed from the AR bound-enhancers RNAs (AR-eRNAs) are upregulated in human CRPC cells in vitro, xenografts in vivo and patient tissues. Expression of a subset of genes with elevated AR-eRNAs, including TLE1 and HTR3A, is inversely correlated with biochemical recurrence-free survival of CRPC patients. We identify aan HIV-1 TAR-like (TAR-L) motif in AR-eRNAs of AR target genes including KLK3 (or PSA) and TMPRSS2. The TAR-L motif is important for these eRNAs to bind to CYCLIN T1 of the positive transcription elongation factor b (P-TEFb) complex. Knockdown of PSA eRNA diminishes RNA polymerase II (Pol II) serine-2 (Ser-2) phosphorylation at the PSA promoter. The TAR-L motif in KLK3 eRNA is crucial for effective transcription of PSA mRNA. Together, wWe demonstrate a P-TEFb activation function of eRNA and reveal aberrant eRNA expression as a functional indicator of AR abnormality in CRPC. Our results also suggest that eRNAs as amay be a potential target for CRPC therapy. Androgen receptor (AR) binding sites in human prostate cancer cell lines, LNCaP and C4-2, were studied using ChIP-seq. ChIP enriched and input DNA were sequenced using Illumina HiSeq 2000.
Project description:The aberrant expression of androgen receptor (AR)-dependent transcriptional programs is a defining pathology of the development and progression of prostate cancers. Transcriptional cofactors that bind AR are critical determinants of prostate tumorigenesis. To gain a deeper understanding of the proteins linked to AR-dependent gene transcription, we performed a DNAaffinity chromatography-based proteomic screen designed to identify proteins involved in ARmediated gene transcription in prostate tumor cells.
Project description:Although the vital role of the androgen receptor (AR) has been well demonstrated in primary prostate cancers, its role in the androgen-insensitive prostate cancers still remains unclear. Here, we used a small hairpin RNA approach to directly assess AR activity in prostate cancer cells. Reduction of AR expression in the two androgen-sensitive prostate cancer cell lines, LNCaP and LAPC4, significantly decreased AR-mediated transcription and cell growth. Intriguingly, in two androgen-insensitive prostate cell lines, LNCaP-C42B4 and CWR22Rv1, knockdown of AR expression showed a more pronounced effect on AR-induced transcription and cell growth than androgen depletion. Using cDNA microarrays, we also compared the transcriptional profiles induced by either androgen depletion or AR knockdown. Although a significant number of transcripts appear to be regulated by both androgen depletion and AR knockdown, we observed a subset of transcripts affected only by androgen depletion but not by AR knockdown, and vice versa. Finally, we demonstrated a direct role for AR in promoting tumor formation and growth in a xenograft model. Taken together, our results elucidate an important role for the AR in androgen-insensitive prostate cancer cells, and suggest that AR can be used as a therapeutic target for androgen-insensitive prostate cancers.
Project description:Prostate cancer is the most common cancer in men and androgen receptor (AR) downstream signalings promote prostate cancer cell proliferation. To investigate the AR signaling, we performed directional RNA sequence analysis in AR positive prostate cancer cell line, LNCaP and VCaP. Using Noncode and GENCODE data sets. We identified androgen-regulated long non-coding RNAs (lncRNAs) in prostate cancer cells. Directional RNA sequence analysis of androgen-regulated lncRNAs in prostate cancer cells
Project description:Androgen receptor (AR) is a hormone-activated transcription factor that plays important roles in prostate development, function, as well as malignant transformation. The downstream pathways of AR, however, are incompletely understood. AR has been primarily known as a transcriptional activator inducing prostate-specific gene expression. Through integrative analysis of genome-wide AR occupancy and androgen-regulated gene expression, here we report AR as a globally acting transcriptional repressor. This repression is mediated by androgen responsive elements (ARE) and dictated by Polycomb group protein EZH2 and repressive chromatin remodeling. In embryonic stem cells, AR-repressed genes are occupied by EZH2 and harbor bivalent H3K4me3 and H3K27me3 modifications that are characteristic of differentiation regulators, the silencing of which maintains the undifferentiated state. Concordantly, these genes are silenced in castration-resistant prostate cancer rendering a stem cell-like lack of differentiation and tumor progression. Collectively, our data reveal an unexpected role of AR as a transcriptional repressor inhibiting non-prostatic differentiation and, upon excessive signaling, resulting in cancerous de-differentiation. It provides an innovative mechanism for castration resistance and highlights novel therapeutic strategies to treat advanced prostate cancer. Keywords: Genetic Modification compare gene expression in different cell lines with or without androgen treatment or EZH2 knockdown