Project description:We profiled androgen receptor (AR) genomic targets using high-throughput sequencing of chromatin-immunoprecipitated (ChIP) DNA from TMPRSS2-ERG fusion gene positive DUCaP prostate cancer cells. ChIp-seq and microarray gene expression profiling datasets were integrated with the NHGRI GWAS PCa risk SNPs catalog to identify disease susceptibility SNPs localized within functional androgen receptor binding sites (ARBSs). Eighty GWAS index or linked SNPs were found to be localized in ARBSs. Among these rs11891426:T>G in the 7th intron of the melanophilin gene was found located within a novel putative auxiliary AR binding motif, which we found enriched in the neighborhood of canonical androgen responsive elements. T→G exchange attenuated the transcriptional activity of the ARBS in an AR reporter gene assay of prostate cancer cell models. It went also in line with decreased melanophilin protein level in primary prostate tumors with G allele.These results unravel a hidden link between androgen receptor and a functional PCa risk SNP, whose allele alteration affects androgen regulation of its host gene melanophilin . Genomic profile of androgen receptor binding sites of androgen or vehicle treated DUCaP cells using ChIP-seq. IgG precipiated DNAs from both treatments served as controls.
Project description:Genome-wide association studies (GWAS) have identified dozens of genomic loci, whose single nucleotide polymorphisms (SNPs) predispose to prostate cancer (PCa). However, the biological functions of these common genetic variants and the mechanisms to increase disease risk are largely unknown. We integrated chromatin-IP coupled sequencing (ChIP-seq) and microarray expression profiling in the TMPRSS2-ERG gene rearrangement positive DuCaP cell model with the NHGRI GWAS PCa risk SNPs catalog, in an attempt to identify disease susceptibility SNPs localized within functional androgen receptor binding sites (ARBSs). Among the 48 GWAS index SNPs and 2,702 linked SNPs defined by the 1000G project 104 were found to be localized in the AR ChIP-seq peaks. Of these risk SNPs, rs11891426 T/G in the 7th intron of its host gene melanophilin (MLPH) was found located within a putative auxiliary ARE motif, which we found enriched in the neighborhood of canonical ARE motifs. Exchange of T to G attenuated the transcriptional activity of the MLPH-ARBS in a reporter gene assay. The expression of MLPH protein in tissue samples from prostate cancer patients was significantly lower in those with the G compared to the T allele. Moreover, a significant positive correlation of AR and MLPH protein expression levels was also confirmed in tissue samples. These results unravel a hidden link between AR and a functional PCa risk SNP rs11891426, whose allele alteration affects androgen regulation of its host gene MLPH. This study shows the power of integrative studies to pin down functional risk SNPs and justifies further investigations.
Project description:We profiled androgen receptor (AR) genomic targets using high-throughput sequencing of chromatin-immunoprecipitated (ChIP) DNA from TMPRSS2-ERG fusion gene positive DUCaP prostate cancer cells. ChIp-seq and microarray gene expression profiling datasets were integrated with the NHGRI GWAS PCa risk SNPs catalog to identify disease susceptibility SNPs localized within functional androgen receptor binding sites (ARBSs). Eighty GWAS index or linked SNPs were found to be localized in ARBSs. Among these rs11891426:T>G in the 7th intron of the melanophilin gene was found located within a novel putative auxiliary AR binding motif, which we found enriched in the neighborhood of canonical androgen responsive elements. T→G exchange attenuated the transcriptional activity of the ARBS in an AR reporter gene assay of prostate cancer cell models. It went also in line with decreased melanophilin protein level in primary prostate tumors with G allele.These results unravel a hidden link between androgen receptor and a functional PCa risk SNP, whose allele alteration affects androgen regulation of its host gene melanophilin .
Project description:<p>Prostate Cancer (PrCa), the most frequently diagnosed solid tumor in men in the U.S., results in ~192,000 new cases and ~27,000 deaths per year. Although the variation of PrCa incidence is likely to be the result of several factors, there is a large body of literature that strongly implicates a genetic etiology. Genome-wide association studies (GWAS) have emerged as the most widely used contemporary approach to identify genetic variants (in particular SNPs) that are associated with increased risk of human disease. For PrCa, at least five GWAS have now been performed yielding a substantial number of well-validated SNPs that are associated with an increased risk of PrCa, and that number continues to grow. A significant problem for many of the PrCa risk-SNPs identified so far, however, is that they do not lie within or near a known gene and they have no obvious functional properties. These findings suggest that many (if not most) of these risk-SNPs will be located in regulatory regions that control gene expression rather than in coding regions that may directly affect protein function. Therefore, in order to define the functional role of currently known risk-SNPs, the target genes must first be identified. A promising strategy to address this problem involves the use of expression quantitative trait loci (eQTL) analysis. Unfortunately, most of the publically available SNP-Transcript eQTL datasets utilize lymphoblastoid cells with only a handful using tissue from target organs. Although useful, these datasets alone are unlikely to be sufficient. Recent studies have demonstrated that gene expression and gene regulation occur in both a tissue-specific and tissue independent fashion and suggest that a complete repertoire of regulatory SNPs can only be uncovered in the context of cell type specificity. To date, such a tissue-specific dataset for normal prostate tissue does not exist. In this study, we have constructed a normal prostate tissue specific eQTL data set. </p>
Project description:Genome-wide association studies (GWAS) have revolutionized the field of cancer genetics, but the causal links between increased genetic risk and onset/progression of disease processes remain to be identified. Here we report the first step in such an endeavor for prostate cancer. We provide a comprehensive annotation of the 77 known risk loci, based upon highly correlated variants in biologically relevant chromatin annotations- we identified 727 such potentially functional SNPs. We also provide a detailed account of possible protein disruption, microRNA target sequence disruption and regulatory response element disruption of all correlated SNPs at r^2≥0.5. Greater than 88% of the 727 SNPs fall within putative enhancers, many of which alter critical residues in the response elements of transcription factors known to be involved in prostate biology. We define as risk enhancers those regions with enhancer chromatin biofeatures in prostate-derived cell lines with prostate-cancer correlated SNPs. To aid in the identification of these enhancers, we performed genomewide ChIP-seq for H3K27-acetylation, a mark of actively engaged enhancer regions, as well as the transcription factor TCF7L2. We analyzed in depth three variants in risk enhancers, two of which show significantly altered androgen sensitivity in LNCaP cells. This includes rs4907792, that is in linkage disequilibrium (r^2=0.91) with an eQTL for NUDT11 (on the X chromosome) in prostate tissue, and rs10486567, the index SNP in intron 3 of the JAZF1 gene on chromosome 7. Rs4907792 is within a critical residue of a strong consensus androgen response element that is interrupted in the protective allele, resulting in a 56% decrease in its androgen sensitivity, whereas rs10486567 affects both NKX3-1 and FOXA-AR motifs where the risk allele results in a 39% increase in basal activity and a 28% fold-increase in androgen stimulated enhancer activity. Identification of such enhancer variants and their potential target genes represents a preliminary step in connecting risk to disease process. ChIP-seq analysis of H3K27Ac in LNCaP charcoal-stripped serum, H3K27Ac in LNCaP charcoal-stripped serum +DHT, TCF7L2 in LNCaP
Project description:We adapted the DiR barcode-based parallel reporter assay systems strategy to systematically identify the SNPs that affect gene expression by modulating activities of regulatory elements. Among 293 SNPs linked with GWAS-identified prostate cancer-risk SNPs, we found 32, 9, and 11 regulatory SNPs in 22Rv1, PC-3, and LNCaP cells. Further mechanism study indicates that one SNP regulates gene expression in prostate cancer malignancy. The DiR system has great potential to advance the functional study of risk SNPs that have associations with polygenic diseases. Our findings hold great promise in benefiting prostate cancer patients with prognostic prediction.
Project description:Genome-wide association studies (GWAS) have revolutionized the field of cancer genetics, but the causal links between increased genetic risk and onset/progression of disease processes remain to be identified. Here we report the first step in such an endeavor for prostate cancer. We provide a comprehensive annotation of the 77 known risk loci, based upon highly correlated variants in biologically relevant chromatin annotations- we identified 727 such potentially functional SNPs. We also provide a detailed account of possible protein disruption, microRNA target sequence disruption and regulatory response element disruption of all correlated SNPs at r^2≥0.5. Greater than 88% of the 727 SNPs fall within putative enhancers, many of which alter critical residues in the response elements of transcription factors known to be involved in prostate biology. We define as risk enhancers those regions with enhancer chromatin biofeatures in prostate-derived cell lines with prostate-cancer correlated SNPs. To aid in the identification of these enhancers, we performed genomewide ChIP-seq for H3K27-acetylation, a mark of actively engaged enhancer regions, as well as the transcription factor TCF7L2. We analyzed in depth three variants in risk enhancers, two of which show significantly altered androgen sensitivity in LNCaP cells. This includes rs4907792, that is in linkage disequilibrium (r^2=0.91) with an eQTL for NUDT11 (on the X chromosome) in prostate tissue, and rs10486567, the index SNP in intron 3 of the JAZF1 gene on chromosome 7. Rs4907792 is within a critical residue of a strong consensus androgen response element that is interrupted in the protective allele, resulting in a 56% decrease in its androgen sensitivity, whereas rs10486567 affects both NKX3-1 and FOXA-AR motifs where the risk allele results in a 39% increase in basal activity and a 28% fold-increase in androgen stimulated enhancer activity. Identification of such enhancer variants and their potential target genes represents a preliminary step in connecting risk to disease process.
Project description:Genome-wide association studies (GWAS) are identifying genetic predisposition to various diseases. The rs1859962 single nucleotide polymorphism (SNP) part of the 17q24.3 locus is a risk factor for prostate cancer (PCa). It defines a 130kb linkage disequilibrium (LD) block that lies in a ~2Mb gene desert area. Despite a role for the proximal SOX9 gene in PCa development, the functional biology driving the risk of this 17q24.3 risk locus is unknown. In the present study, we integrate genome-wide chromatin landscape datasets, namely epigenomes and chromatin openness from diverse cell-types to identify one PCa specific enhancer within the rs1859962 risk LD block. We reveal that this enhancer is part of a 1Mb chromatin loop with the SOX9 gene in PCa cells. The rs8072254 and rs1859961 SNPs part of this LD block map to this enhancer and impose allele-specific gene expression. The variant allele of rs1859961 directly decreases FoxA1 binding while increasing AP-1 binding compared to the reference allele. This latter is key in driving allele-specific gene expression. Together, our results demonstrate the risk associated with the PCa rs1859962 risk LD block is accounted for by multiple genetic variants mapping to a unique enhancer looping to the SOX9 oncogene. Allele-specific recruitment of the transcription factor AP-1 accounts in part for the increased enhancer activity ascribed to this PCa risk LD block. This further demonstrates that an integrative genomics approach can identify the functional biology disrupted by genetic risk-variants. Examination of histone modification H3K36me3 in the prostate cancer LNCaP cell line under DHT treatment.