Xiao Yuzhen, Huang Wei, Huang Hongyan, Wang Lei, Wang Min, Zhang Tingting, Fang Xiaoling, Xia Xiaomeng
Department of Obstetrics and Gynecology, The Second Xiangya Hospital, Central South University, Changsha, China.
Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, Changsha, China.
DNA Cell Biol. 2021 Apr;40(4):618-628. doi: 10.1089/dna.2020.6379. Epub 2021 Mar 22.
The expressions and roles of protein inhibitor of activated STAT (PIAS) proteins, a group of proteins with STAT inhibition and SUMOylation E3 ligase activity, are rarely revealed in endometrial cancer (EC). In this study, we analyzed the expressions of PIASs and their relationships with clinical features by mining online data through web servers, including UALCAN and Gene Expression Profiling Interactive Analysis (GEPIA) in EC. The expressions of PIASs in EC tissues were further validated by immunohistochemistry (IHC). The online analyses revealed only PIAS1 was consistently downregulated both at mRNA and protein level in EC, which was validated by the IHC. Subsequently, the mechanism of PIAS1 downregulation was explored with online tools like UALCAN, cBioPortal, LinkedOmics, and the Encyclopedia of RNA Interactomes (ENCORI). The results indicated that the mutation rate of PIAS1 was extremely low and not associated with PIAS1 expression. The promoter methylation level of PIAS1 was comparable between normal and EC tissues. miR-182-5p and miR-96-5p with negative association with PIAS1 in EC were predicted to target PIAS1. Dual luciferase reporter assay confirmed miR-182-5p and miR-96-5p could target PIAS1 in EC. MiR-182-5p and miR-96-5p inhibitors could upregulate PIAS1 in EC cells. Moreover, ectopic PIAS1 expression and STAT3 inhibitor treatment significantly inhibited STAT3's activity and the levels of miR-182-5p and miR-96-5p in EC cells. Collectively, our findings revealed PIAS1 was downregulated in EC, which was caused by upregulation of miR-182-5p and miR-96-5p, and PIAS1 downregulation further activated STAT3 and increased the expression of miR-182-5p and miR-96-5p, confirming miR-182-5p and miR-96-5p mediated the negative feedback regulatory loop between PIAS1 and STAT3 in EC.
信号转导和转录激活因子（STAT）激活蛋白抑制剂（PIAS）家族蛋白具有抑制STAT和SUMO化E3连接酶活性，其在子宫内膜癌（EC）中的表达及作用鲜有报道。本研究通过UALCAN和基因表达谱交互式分析（GEPIA）等网络服务器挖掘在线数据，分析了PIAS家族蛋白在EC中的表达及其与临床特征的关系。通过免疫组织化学（IHC）进一步验证了PIAS家族蛋白在EC组织中的表达。在线分析显示，仅PIAS1在EC的mRNA和蛋白水平均持续下调，并经IHC验证。随后，利用UALCAN、cBioPortal、LinkedOmics和RNA相互作用组百科全书（ENCORI）等在线工具探索了PIAS1下调的机制。结果表明，PIAS1的突变率极低，且与PIAS1表达无关。PIAS1的启动子甲基化水平在正常组织和EC组织之间相当。预测在EC中与PIAS1呈负相关的miR-182-5p和miR-96-5p靶向PIAS1。双荧光素酶报告基因检测证实miR-182-5p和miR-96-5p可在EC中靶向PIAS1。miR-182-5p和miR-96-5p抑制剂可上调EC细胞中PIAS1的表达。此外，异位表达PIAS1和使用STAT3抑制剂处理可显著抑制EC细胞中STAT3的活性以及miR-182-5p和miR-96-5p的水平。总之，我们的研究结果表明，PIAS1在EC中下调，这是由miR-182-5p和miR-96-5p上调所致，而PIAS1下调进一步激活STAT3并增加miR-182-5p和miR-96-5p的表达，证实miR-182-5p和miR-96-5p介导了EC中PIAS1与STAT3之间的负反馈调节环。
