Kong Fanfei, Sun Chaoyang, Wang Zhongxian, Han Lingfei, Weng Danhui, Lu Yunping, Chen Gang
Cancer Biology Research Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China.
J Huazhong Univ Sci Technolog Med Sci. 2011 Aug;31(4):543. doi: 10.1007/s11596-011-0487-z. Epub 2011 Aug 7.
Chemotherapy is the preferred therapeutic approach for advanced ovarian cancer, but a successful long-term treatment is prevented by the development of drug resistance. Recent works have underlined the involvement of non-coding RNAs, microRNAs (miRNAs) in cancer development, with several conjectures regarding their possible involvement in the evolution of drug resistance. This study is to investigate the promoting effects and mechanism of miR-125b involved in the development of chemoresistance in ovarian cancer. The different expression of miR-125b in cisplatin-sensitive ovarian cancer cell line (OV2008) and its resistant variant (C13*) was identified by real-time PCR. An in vitro cytotoxicity assay and apoptosis assay using CCK-8 assay and flow cytometry, were carried out to detect the effect of miR-125b and Bak1 on cisplatin resistance of cells. Real-time PCR, Western blotting and luciferase reporter assay were used to detect whether Bak1 is a target of miR-125b. As compared with OV2008 cells, the expression levels of miR-125b in C13* cells were increased. It was found that the up-regulation of microRNA-125b caused a marked inhibition of cisplatin-induced cytotoxicity and apoptosis and a subsequent increase in the resistance to cisplatin in OV2008 and C13* cells. Moreover, Bak1 was a direct target of miR-125b, and down-regulation of Bak1 suppressed cisplatin-induced apoptosis and led to an increased resistance to cisplatin. Our study indicates that miR-125b has a significantly promoting effect on chemoresistance of C13* cells and up-regulation of miR-125b expression contributes to cisplatin resistance through suppression of Bak1 expression. This finding has important implications in the development of targeted therapeutics for overcoming cisplatin resistance in ovarian cancer.
化疗是晚期卵巢癌的首选治疗方法，但耐药性的产生阻碍了长期治疗的成功。最近的研究强调了非编码RNA，即微小RNA（miRNA）在癌症发展中的作用，并对它们可能参与耐药性演变提出了几种推测。本研究旨在探讨miR-125b在卵巢癌化疗耐药发展中的促进作用及其机制。通过实时PCR鉴定了顺铂敏感的卵巢癌细胞系（OV2008）及其耐药变体（C13*）中miR-125b的不同表达。采用CCK-8法和流式细胞术进行体外细胞毒性试验和凋亡试验，以检测miR-125b和Bak1对细胞顺铂耐药性的影响。利用实时PCR、蛋白质免疫印迹法和荧光素酶报告基因检测法检测Bak1是否为miR-125b的靶标。与OV2008细胞相比，C13细胞中miR-125b的表达水平升高。研究发现，微小RNA-125b的上调显著抑制了顺铂诱导的细胞毒性和凋亡，并随后增加了OV2008和C13细胞对顺铂的耐药性。此外，Bak1是miR-125b的直接靶标，Bak1的下调抑制了顺铂诱导的凋亡，并导致对顺铂的耐药性增加。我们的研究表明，miR-125b对C13*细胞的化疗耐药具有显著的促进作用，miR-125b表达的上调通过抑制Bak1的表达导致顺铂耐药。这一发现对开发克服卵巢癌顺铂耐药的靶向治疗具有重要意义。
