Department of Urology, Roswell Park Comprehensive Cancer Center, Buffalo, New York.
Department of Biostatistics and Bioinformatics, Roswell Park Comprehensive Cancer Center, Buffalo, New York.
Mol Cancer Ther. 2022 May 4;21(5):786-798. doi: 10.1158/1535-7163.MCT-21-0613.
Neoadjuvant chemotherapy (NAC) followed by radical cystectomy is the standard-of-care for patients with muscle-invasive bladder cancer (MIBC). Defects in nucleotide excision repair (NER) are associated with improved responses to NAC. Excision Repair Cross-Complementation group 3 (ERCC3) is a key component of NER process. No NER inhibitors are available for treating patients with bladder cancer. We have developed an ex vivo cell-based assay of 6-4 pyrimidine-pyrimidinone (6-4PP) removal as a surrogate measure of NER capacity in human bladder cancer cell lines. The protein expression of ERCC3 was examined in human MIBC specimens and cell lines. Small molecule inhibitors were screened for NER inhibition in bladder cancer cell lines. Spironolactone was identified as a potent NER inhibitor. Combined effects of spironolactone with chemo-drugs were evaluated in vitro and in vivo. The efficacy between platinum and spironolactone on cytotoxicity was determined by combination index. A correlation between NER capacity and cisplatin sensitivity was demonstrated in a series of bladder cancer cell lines. Further, siRNA-mediated knockdown of ERCC3 abrogated NER capacity and enhanced cisplatin cytotoxicity. Spironolactone inhibited ERCC3 protein expression, abrogated NER capacity, and increased platinum-induced cytotoxicity in bladder cancer cells in vivo and in patient-derived organoids. Moreover, spironolactone exhibited the potential synergism effects with other clinical chemotherapy regimens in bladder cancer cell lines. Our data support the notion of repurposing spironolactone for improving the chemotherapy response of NAC in patients with MIBC. Further clinical trials are warranted to determine the safety and efficacy of spironolactone in combination with chemotherapy.
新辅助化疗（NAC）后行根治性膀胱切除术是肌层浸润性膀胱癌（MIBC）患者的标准治疗方法。核苷酸切除修复（NER）缺陷与 NAC 反应改善相关。切除修复交叉互补组 3（ERCC3）是 NER 过程的关键组成部分。目前尚无 NER 抑制剂可用于治疗膀胱癌患者。我们开发了一种基于体外细胞的 6-4 嘧啶-嘧啶酮（6-4PP）去除检测方法，作为人膀胱癌细胞系 NER 能力的替代测量方法。在人 MIBC 标本和细胞系中检测了 ERCC3 的蛋白表达。筛选小分子抑制剂以抑制膀胱癌细胞系中的 NER。螺内酯被鉴定为一种有效的 NER 抑制剂。评估了螺内酯与化疗药物联合在体外和体内的效果。通过组合指数确定了顺铂和螺内酯对细胞毒性的疗效。在一系列膀胱癌细胞系中证明了 NER 能力与顺铂敏感性之间存在相关性。此外，siRNA 介导的 ERCC3 敲低消除了 NER 能力，并增强了顺铂在膀胱癌细胞中的细胞毒性。螺内酯抑制 ERCC3 蛋白表达，消除 NER 能力，并增加体内和患者来源的类器官中铂诱导的细胞毒性。此外，螺内酯在膀胱癌细胞系中与其他临床化疗方案联合具有潜在的协同作用。我们的数据支持将螺内酯重新用于改善 MIBC 患者 NAC 的化疗反应的观点。需要进一步的临床试验来确定螺内酯联合化疗的安全性和疗效。
