Tao Tao, Liu Dachuang, Liu Chunhui, Xu Bin, Chen Shuqiu, Yin Yu, Ang Lin, Huang Yeqing, Zhang Xiaowen, Chen Ming
Department of Urology, Zhongda Hospital, Medical School, Southeast University, Nanjing 210009, China; Surgical Research Center, Medical School, Southeast University, Nanjing 210009, China; Institute of Urology, Southeast University, Nanjing 210009, China.
Department of Urology, Zhongda Hospital, Medical School, Southeast University, Nanjing 210009, China; Surgical Research Center, Medical School, Southeast University, Nanjing 210009, China.
Biochim Biophys Acta. 2014 Sep;1839(9):858-65. doi: 10.1016/j.bbagrm.2014.07.001. Epub 2014 Jul 10.
The histone methyltransferase enhancer of zeste homolog 2 (EZH2) has recently attracted considerable attention because of its dysregulation in prostate cancer (PCa) and its important function in PCa development. To date, little is known about the underlying cellular function and regulatory networks of EZH2 in PCa. This study aims to determine whether or not the autoregulatory feedback loop of EZH2/miR-200c/E2F3 serves key functions in PCa development. Bioinformatics and integrative analytical approaches were employed to identify the relationships of EZH2 to specific cancer-related gene sets. Results indicated that the enrichment of gene sets about cell cycle progression was associated with EZH2 expression. The depletion of EZH2 in cell experiments inhibited PCa cell growth and blocked cell cycle accompanying the downregulation of E2F3 expression. Furthermore, miR-200c served as an important mediator between EZH2 and E2F3. Compared with scrambled control cells, sh-EZH2 cells showed lower H3K27me3 expression and higher miR-200c expression. Western blot and luciferase reporter assays showed that miR-200c inversely modulated E2F3 by directly targeting the binding site within 3'UTR. Moreover, decreased miR-200c expression largely abrogated the effect of sh-EZH2 on E2F3 expression and E2F3-induced cell cycle progression. EZH2 was positively regulated by E2F3 at the transcriptional level. Immunohistochemistry and in situ hybridization revealed a significant correlation among EZH2, miR-200c, and E2F3 expression in human PCa tissues. In conclusion, the autoregulatory feedback loop of EZH2/miR-200c/E2F3 served an important function in PCa development. Targeting this aberrantly activated feedback loop may provide a new therapeutic strategy against PCa.
zeste同源物2（EZH2）组蛋白甲基转移酶增强子最近因其在前列腺癌（PCa）中的失调及其在PCa发展中的重要功能而备受关注。迄今为止，关于EZH2在PCa中的潜在细胞功能和调控网络知之甚少。本研究旨在确定EZH2/miR-200c/E2F3的自动调节反馈环在PCa发展中是否发挥关键作用。采用生物信息学和综合分析方法来确定EZH2与特定癌症相关基因集之间的关系。结果表明，与细胞周期进程相关的基因集富集与EZH2表达有关。细胞实验中EZH2的缺失抑制了PCa细胞生长并阻滞了细胞周期，同时伴随着E2F3表达的下调。此外，miR-200c是EZH2和E2F3之间的重要介质。与对照细胞相比，sh-EZH2细胞显示出较低的H3K27me3表达和较高的miR-200c表达。蛋白质印迹和荧光素酶报告基因检测表明，miR-200c通过直接靶向3'UTR内的结合位点反向调节E2F3。此外，miR-200c表达的降低在很大程度上消除了sh-EZH2对E2F3表达和E2F3诱导的细胞周期进程的影响。EZH2在转录水平上受到E2F3的正向调节。免疫组织化学和原位杂交显示，在人PCa组织中EZH2、miR-200c和E2F3表达之间存在显著相关性。总之，EZH2/miR-200c/E2F3的自动调节反馈环在PCa发展中发挥了重要作用。针对这种异常激活的反馈环可能提供一种新的PCa治疗策略。
