Department of Surgery, Division of Urology, McGill University and the Cancer Research Program of the McGill University Health Centre Research Institute, Montreal, Quebec, H4A 3J1, Canada.
Movember/Prostate Cancer UK Centre of Excellence for Prostate Cancer Research, Centre for Cancer Research and Cell Biology (CCRCB), Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK.
Mol Cell Endocrinol. 2018 Aug 15;471:1-14. doi: 10.1016/j.mce.2017.05.006. Epub 2017 May 5.
The androgen receptor (AR) is a transcription factor, and key regulator of prostate development and cancer, which has discrete functions in stromal versus epithelial cells. AR expressed in mesenchyme is necessary and sufficient for prostate development while loss of stromal AR is predictive of prostate cancer progression. Many studies have characterized genome-wide binding of AR in prostate tumour cells but none have used primary mesenchyme or stroma. We applied ChIPseq to identify genomic AR binding sites in primary human fetal prostate fibroblasts and patient derived cancer associated fibroblasts, as well as the WPMY1 cell line overexpressing AR. We identified AR binding sites that were specific to fetal prostate fibroblasts (7534), cancer fibroblasts (629), WPMY1-AR (2561) as well as those common among all (783). Primary fibroblasts had a distinct AR binding profile versus prostate cancer cell lines and tissue, and showed a localisation to gene promoter binding sites 1 kb upstream of the transcriptional start site, as well as non-classical AR binding sequence motifs. We used RNAseq to define transcribed genes associated with AR binding sites and derived cistromes for embryonic and cancer fibroblasts as well as a cistrome common to both. These were compared to several in vivo ChIPseq and transcript expression datasets; which identified subsets of AR targets that were expressed in vivo and regulated by androgens. This analysis enabled us to deconvolute stromal AR targets active in stroma within tumour samples. Taken together, our data suggest that the AR shows significantly different genomic binding site locations in primary prostate fibroblasts compared to that observed in tumour cells. Validation of our AR binding site data with transcript expression in vitro and in vivo suggests that the AR target genes we have identified in primary fibroblasts may contribute to clinically significant and biologically important AR-regulated changes in prostate tissue.
雄激素受体（AR）是一种转录因子，也是前列腺发育和癌症的关键调节因子，在基质细胞与上皮细胞中具有不同的功能。间质中表达的 AR 对于前列腺的发育是必要的且充分的，而基质 AR 的缺失可预测前列腺癌的进展。许多研究已经对前列腺肿瘤细胞中 AR 的全基因组结合进行了特征描述，但没有使用原代间质或基质。我们应用 ChIPseq 鉴定了原代人胎儿前列腺成纤维细胞和患者来源的癌相关成纤维细胞以及过表达 AR 的 WPMY1 细胞系中 AR 的基因组结合位点。我们鉴定了特定于胎儿前列腺成纤维细胞（7534 个）、癌症成纤维细胞（629 个）、WPMY1-AR（2561 个）以及所有细胞共有的 AR 结合位点（783 个）。与前列腺癌细胞系和组织相比，原代成纤维细胞具有独特的 AR 结合谱，并显示出位于转录起始位点上游 1kb 的基因启动子结合位点以及非经典 AR 结合序列基序的局部化。我们使用 RNAseq 定义与 AR 结合位点相关的转录基因，并为胚胎和成纤维细胞瘤衍生的 cistromes 以及两者共有的 cistrome 进行定义。将这些与多个体内 ChIPseq 和转录表达数据集进行比较；确定了 AR 靶标在体内表达并受雄激素调节的子集。这项分析使我们能够在肿瘤样本中的基质内去卷积基质 AR 靶标。综上所述，我们的数据表明，与在肿瘤细胞中观察到的相比，AR 在原代前列腺成纤维细胞中具有明显不同的基因组结合位点位置。我们通过体外和体内的转录表达验证了我们的 AR 结合位点数据，表明我们在原代成纤维细胞中鉴定的 AR 结合基因可能有助于前列腺组织中具有临床意义和生物学重要性的 AR 调节变化。
