Huo Yi, Zheng Zhiguo, Chen Yuling, Wang Qingtao, Zhang Zhenyu, Deng Haiteng
MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China.
Zhejiang Tumor Hospital, Hangzhou, China.
Oncotarget. 2016 Jul 19;7(29):45876-45888. doi: 10.18632/oncotarget.9970.
Cisplatin and other platinum-based drugs have been widely used in the treatment of ovarian cancer, but most patients acquire the drug resistance that greatly compromises the efficacy of drugs. Understanding the mechanism of drug resistance is important for finding new therapeutic approaches. In the present study, we found that the expression of vimentin was downregulated in drug-resistant ovarian cancer cell lines A2780-DR and HO-8910 as compared to their respective control cells. Overexpression of vimentin in A2780-DR cells markedly increased their sensitivity to cisplatin, whereas knockdown of vimentin in A2780, HO-8910-PM and HO-8910 cells increased the resistance to cisplatin, demonstrating that vimentin silencing enhanced cisplatin resistance in ovarian cancer cells. Quantitative proteomic analysis identified 95 differentially expressed proteins between the vimentin silenced A2780 cells (A2780-VIM-KN) and the control cells, in which downregulation of endocytic proteins and the upregulation of exocytotic proteins CHMP2B and PDZK1 were proposed to contribute the decreased cisplatin accumulation in vimentin knockdown cells. Silencing of vimentin induced upregulation of cancer stem cell markers and both A2780-DR and A2780-VIM-KN cells were more facile to form spheroids than control cells under serum-free culture condition. Our results also revealed that vimentin knockdown increased the 14-3-3 mediated retention of Cdc25C in the cytoplasm, leading to inactivation of Cdk1 and the prolonged G2 phase arrest that allowed the longer period of time for cells to repair cisplatin-damaged DNA. Taken together, we demonstrated that vimentin silencing enhanced cells' resistance to cisplatin via prolonged G2 arrest and increased exocytosis, suggesting that vimentin is a potential target for treatment of drug resistant ovarian cancer.
顺铂和其他铂类药物已广泛用于卵巢癌的治疗，但大多数患者会产生耐药性，这大大降低了药物的疗效。了解耐药机制对于寻找新的治疗方法很重要。在本研究中，我们发现与各自的对照细胞相比，波形蛋白在耐药卵巢癌细胞系A2780-DR和HO-8910中的表达下调。在A2780-DR细胞中过表达波形蛋白显著增加了它们对顺铂的敏感性，而在A2780、HO-8910-PM和HO-8910细胞中敲低波形蛋白则增加了对顺铂的耐药性，表明波形蛋白沉默增强了卵巢癌细胞对顺铂的耐药性。定量蛋白质组学分析确定了波形蛋白沉默的A2780细胞（A2780-VIM-KN）与对照细胞之间有95种差异表达的蛋白质，其中内吞蛋白的下调以及胞吐蛋白CHMP2B和PDZK1的上调被认为是导致波形蛋白敲低细胞中顺铂积累减少的原因。波形蛋白的沉默诱导了癌症干细胞标志物的上调，并且在无血清培养条件下，A2780-DR和A2780-VIM-KN细胞比对照细胞更容易形成球体。我们的结果还表明，波形蛋白敲低增加了14-3-3介导的Cdc25C在细胞质中的滞留，导致Cdk1失活和G2期延长停滞，这使得细胞有更长的时间来修复顺铂损伤的DNA。综上所述，我们证明波形蛋白沉默通过延长G2期停滞和增加胞吐作用增强了细胞对顺铂的耐药性，表明波形蛋白是治疗耐药卵巢癌的潜在靶点。
