Project description:A high-resolution 3D epigenomic map reveals insights into the creation of the prostate cancer transcriptome Prostate cancer (PCa) is the leading cancer among men in the United States. To understand gene regulation in 3D, chromatin interactions in prostate cancer cell is measured using in situ Hi-C. To better understand the impact of chromatin structure on regulation of the prostate cancer transcriptome, we developed high-resolution chromatin interaction maps in normal and prostate cancer cells using in situ Hi-C. By combining the in situ Hi-C data with active and repressive histone marks, CTCF binding sites, nucleosome-depleted regions, and transcriptome profiling, we identified topologically associating domains that changed in size and epigenetic states between normal and prostate cancer cells. Moreover, we identified normal and prostate cancer-specific enhancer-promoter loops and involved transcription factors. This creation of 3D epigenomic maps will enable a better understanding of prostate cancer biology and mechanisms of gene regulation.
Project description:We used chromatin immunoprecipitation (ChIP) in combination with human promoter microarrays to idnetify SUZ12 and H3K27me3-occupied gene promoters in prostate cancer cells and tissues. We observed a common set of SUZ12 and H3K27me3-occupied genes in LNCaP cells, and metastatic prostate cancer tissues across individuals as well as tissue types of the metastatic sites. We also found significant overlap of cancer polycomb targets with previously published embryonic stem cell polycomb targets. In addition, a strong association between cancer polycomb targets with prostate cancer outcome was observed. We developed a cancer Polycomb Repression Signature, comprised direct targets of PRC2 silencing in cancer, that is predictive of cancer outcome in multiple expression profling datasets of tumors. Keywords: protein-DNA interaction
Project description:An aberrant androgen receptor (AR) transcriptional network underpins prostate cancer development. Even though the AR cistrome had been extensively studied in prostate cancers, information pertaining to the spatial architecture of the AR transcriptional circuitry remains limited due to the absence of an AR-associated chromatin interactome map. To resolve this, we utilized chromatin interaction analysis by paired-end tag (ChIA-PET) sequencing to profile AR-associated and ERG-associated long range chromatin interactions in an ERG fusion positive prostate cancer cell line. We identified ERG-associated long range chromatin interactions as an elemental component in the AR-associated chromatin interactome, acting in concert, to achieve coordinated regulation of AR target genes. In addition, we characterized the epigenetic signature of the AR/ERG anchor binding sites and implicated AR and ERG associated chromatin loopings for facilitating fusion gene formation in prostate cancers. Taken together, our results revealed the presence of an AR/ERG defined higher order chromatin structure exploited for driving prostate cancer progression.
Project description:Growing studies support a direct role for nuclear mTOR in gene regulation and chromatin structure. Still, the scarcity of known chromatin-bound mTOR partners limits our understanding of how nuclear mTOR controls transcription. Herein, we comprehensively mapped the mTOR chromatin-bound interactome in four cellular models of prostate cancer (PCa) identifying a conserved 67-protein interaction network enriched for epigenetic and transcription factors as well as SUMOylation machinery in both androgen-dependent and -independent cells. Notably, SUMO2/3 and nuclear pore protein NUP210 are among the strongest interactors while the androgen receptor (AR) is the dominant androgen-inducible mTOR partner. Further investigation showed that NUP210 facilitates mTOR nuclear trafficking, that mTOR, AR and NuRD act as a functional transcriptional complex, and that androgens dictate mTOR-SUMO2/3 promoter-enhancer specificity. This work identifies a vast network of mTOR-associated nuclear complexes advocating novel molecular strategies to modulate mTOR-dependent gene regulation with evident implications for PCa and other diseases.
Project description:The current study defines the how ERG, PTEN, and AR inteact to regulate the transciptome in established prostate cancers. Prostate cancer organoids were derived from established prostate cancer in GEM models harboring ERG over-expression and/or loss of PTEN and cultured in vitro using prostate epithelial organoid culture conditions. The established organoids were then isolated as individual clones in triplicate and CRISPR strategies were employeed to knock out ERG and AR. ChIP seq was performed under standard growth and media conditions.
Project description:We investigated the composition of chromatin protein network around endogenous androgen receptor (AR) in VCaP castration resistant prostate cancer cells using recently developed chromatin-directed proteomic approach called ChIP-SICAP . The androgen-induced AR chromatin protein network contained expected TFs, e.g. HOXB13, chromatin remodeling proteins, e.g. SMARCA4, and several novel candidates not previously associated with AR, e.g. prostate cancer biomarker SIM2. Based on these findings, the role of SMARCA4 and SIM2 was further characterized at AR chromatin domains . Silencing of SIM2 altered chromatin accessibility at a similar number of AR-binding sites as SMARCA4, an established ATPase subunit of the BAF chromatin remodeling complex, often aberrantly expressed in prostate cancer. Despite the wide co-occurrence on chromatin of SMARCA4 and AR, depletion of SMARCA4 influenced chromatin accessibility and expression of a restricted set of AR target genes, in particular those involved in cell morphogenetic changes in epithelial-mesenchymal transition. Silencing of SIM2, in turn, affected the expression of a much larger group of androgen-regulated genes, e.g. those involved in cellular responses to external stimuli and steroid hormone stimulus. The silencing also reduced proliferation of VCaP cells and tumor size in chick embryo chorioallantoic membrane assay, further suggesting the importance of SIM2 in the regulation prostate cancer cells.
Project description:Vitamin D induces anti-proliferative and differentiating effects in prostate cancer. Thus calcitriol, the hormonally active form of Vitamin D, and its analogs have been extensively studied in prostate cancer cells. Yet despite its importance, relatively little is known about the genome-scale mechanisms by which Vitamin D, through its cognate nuclear vitamin D receptor (VDR), exerts its regulatory functions at the genomic level. In this study, we defined VDR transcriptional networks in the LNCaP prostate cancer cell line by mapping the genomic binding sites of VDR and by identifying differentially expressed genes upon calcitriol treatment. We found that VDR and androgen receptor (AR) antagonistically regulate a subset of cell cycle-related genes that are over-expressed in prostate cancer tumors. The expression balance of these genes is partially regulated through the competition dynamics between AR and VDR binding to shared cis-regulatory elements. On such shared elements, we found that FOXA1 mediates this competition by serving as a pioneering factor for both AR and VDR binding. We also found significant enrichment of AR-, VDR-, and AR/VDR overlapping binding sites in prostate cancer-associated single-nucleotide polymorphism (SNP) intervals identified from genome-wide association studies (GWAS), providing genetic evidence to link AR, VDR and their crosstalk to prostate cancer susceptibilities. In particular, we found that in a cis-regulatory element of the RFX6 gene implicated in prostate cancer progression, an allelic variant increases prostate cancer risk by switching the antagonism between AR and VDR into a synergistic interaction. Examination of AR, VDR, and FOXA1 binding in LNCaP cells, in biological replicates