VPRBP, a novel androgen receptor and OGT target is an essential mediator of cellular transformation in prostate cancer

Androgen receptor (AR) plays a central role in the development of prostate cancer. Increased expression of O-GlcNAc transferase (OGT) and O-GlcNAcylation are also implicated in metastatic prostate caner. We have identified VPRBP as a novel androgen-regulated gene and the stability of the encoded protein is regulated by OGT.VPRBP downregulation led to significant decrease in cell proliferation and p53 stabilization in LNCaPs. In this study, we employed chromatin immunoprecipitation coupled with massive parallel sequencing (ChIP-seq) to identify changes in p53 binding to the genome in VPRBP knockdown LNCaPs compared to scrambled siRNA transfected control cells. Stabilization of p53 was associated increased p53 recruitment to the chromatin. ChIP-seq studies were carried out in nutlin-3a treated LNCaPs, and scrambled siRNA vs VPRBP siRNA 1 and VPRBP siRNA 2 transfected LNCaPs using antibody against p53 (Santa Cruz Biotechnology, sc-126)

雄激素受体（Androgen receptor, AR）在前列腺癌的发生发展中发挥核心调控作用。O-连接β-N-乙酰葡糖胺转移酶（O-GlcNAc transferase, OGT）的表达上调及其介导的O-糖基化（O-GlcNAcylation）也与转移性前列腺癌的发生发展密切相关。本研究团队已鉴定出VPRBP为一种新型雄激素调控基因，其编码蛋白的稳定性受OGT调控。研究发现，VPRBP敲低可显著降低LNCaP细胞的增殖能力并诱导p53稳定。本研究采用染色质免疫共沉淀结合高通量测序（ChIP-seq）技术，对比了VPRBP敲低的LNCaP细胞与转染乱序siRNA的对照细胞中，p53全基因组结合谱的变化。结果显示，p53的稳定与p53在染色质上的招募增加呈相关关系。此外，本研究还在经nutlin-3a处理的LNCaP细胞中开展了ChIP-seq实验，分别使用抗p53抗体（圣克鲁斯生物技术公司，货号sc-126）对转染乱序siRNA、VPRBP siRNA 1及VPRBP siRNA 2的细胞进行检测。