Cao Yudong, Wang Shuo, Ma Jinchao, Long Mengping, Ma Xiuli, Yang Xiao, Ji Yongpeng, Tang Xingxing, Liu Jia, Lin Chen, Yang Yong, Du Peng
Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Urology, Peking University Cancer Hospital & Institute, Beijing, 100142, China.
Key laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Pathology, Peking University Cancer Hospital & Institute, Beijing, 100142, China.
Cell Death Dis. 2024 Dec 24;15(12):931. doi: 10.1038/s41419-024-07321-1.
Cisplatin (CDDP) resistance has been established to significantly impact Bladder Cancer (BCa) therapy. On the other hand, the crucial regulatory involvement of SIRT7 and EZH2 in bladder cancer development is well known. Herein, the collaborative regulatory roles and underlying mechanisms of SIRT7 and EZH2 in CDDP resistance in bladder cancer were explored. Immunohistochemistry (IHC) and Western Blot (WB) analyses were used to assess the expression levels of SIRT7/EZH2 and RND3 in bladder cancer tissues, normal ureteral epithelial cells, and bladder cancer cell lines. Furthermore, the impact of various treatments on of UMUC3 cell proliferation and CDDP sensitivity was assessed using CCK-8 assays, plate cloning assays, and flow cytometry analysis. Additionally, the levels of H3K18ac and H3K27me at the promoter region of the RND3 gene, the binding abilities of SIRT7 and EZH2, and the succinylation level of the EZH2 protein were examined using ChIP-qPCR assays, CO-IP assays, and IP assays, respectively. Moreover, in vivo experiments were conducted using a bladder cancer mouse model created by subcutaneously injecting UMUC3 cells into Balb/c nude mice. According to the results, SIRT7 correlated with the sensitivity of bladder cancer cells to both the platinum-based chemotherapy and CDDP. Specifically, SIRT7 could bind to the RND3 promoter, downregulating H3K18ac and RND3, ultimately leading to an increased CDDP sensitivity in UMUC3 cells. Furthermore, EZH2 siRNA could decrease H3K27me levels in the RND3 promoter, upregulating RND3. Overall, in the promoter region of the RND3 gene, SIRT7 upregulated H3K27me and EZH2 downregulated H3K18ac, leading to a decline in RND3 expression and CDDP sensitivity in bladder cancer cells. Additionally, SIRT7 reduced the succinylation of the EZH2 protein resulting in an EZH2-mediated RND3 downregulation. Therefore, targeting SIRT7 and EZH2 could be a viable approach to enhancing CDDP efficacy in bladder cancer treatment.
顺铂（CDDP）耐药已被证实会显著影响膀胱癌（BCa）的治疗。另一方面，SIRT7和EZH2在膀胱癌发展中的关键调控作用已为人所知。在此，我们探讨了SIRT7和EZH2在膀胱癌顺铂耐药中的协同调控作用及潜在机制。采用免疫组织化学（IHC）和蛋白质免疫印迹（WB）分析评估SIRT7/EZH2和RND3在膀胱癌组织、正常输尿管上皮细胞及膀胱癌细胞系中的表达水平。此外，使用CCK-8法、平板克隆法和流式细胞术分析评估不同处理对UMUC3细胞增殖和顺铂敏感性的影响。另外，分别采用染色质免疫沉淀定量PCR（ChIP-qPCR）法、免疫共沉淀（CO-IP）法和免疫沉淀（IP）法检测RND3基因启动子区域的H3K18ac和H3K27me水平、SIRT7和EZH2的结合能力以及EZH2蛋白的琥珀酰化水平。此外，通过将UMUC3细胞皮下注射到Balb/c裸鼠体内建立膀胱癌小鼠模型进行体内实验。结果显示，SIRT7与膀胱癌细胞对铂类化疗药物和顺铂的敏感性相关。具体而言，SIRT7可与RND3启动子结合，下调H3K18ac和RND3，最终导致UMUC3细胞对顺铂的敏感性增加。此外，EZH2小干扰RNA可降低RND3启动子区域的H3K27me水平，上调RND3。总体而言，在RND3基因启动子区域，SIRT7上调H3K27me，EZH2下调H3K18ac，导致膀胱癌细胞中RND3表达下降和顺铂敏感性降低。此外，SIRT7降低了EZH2蛋白的琥珀酰化，导致EZH2介导的RND3下调。因此，靶向SIRT7和EZH2可能是提高膀胱癌治疗中顺铂疗效的可行方法。
