Rao Yu-Mei, Shi Hui-Rong, Ji Mei, Chen Cai-Hong
Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
Center of Reproductive Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
J Huazhong Univ Sci Technolog Med Sci. 2013 Aug;33(4):567-572. doi: 10.1007/s11596-013-1160-5. Epub 2013 Aug 1.
Resistance to chemotherapy is a major obstacle for the effective treatment of advanced ovarian cancer. The mechanism of chemoresistance is still poorly understood. Recently, more and more evidence showed microRNAs (miRNAs) modulated many key molecules and pathways involved in chemotherapy. microRNA-106a (miR-106a) has been implicated in many cancers, but its role in ovarian cancer and drug resistance still remains unexplored. This study was to investigate whether miR-106a mediated resistance of the ovarian cancer cell line A2780 to the chemotherapeutic agent cisplatin (DDP). The different levels of miR-106a in A2780 cells and their resistant variant A2780/DDP cells were identified by using real-time PCR. MTT assay and flow cytometry were used to analyze the effect of miR-106a on cisplatin resistance of these paired cells. Real-time PCR, Western blotting and luciferase reporter assay were applied to explore whether Mcl-1 was a target of miR-106a. As compared to A2780 cells, the expression of miR-106a was down-regulated in the cisplatin resistant cell line A2780/DDP. Moreover, knockdown of miR-106a dramatically decreased antiproliferative effects and apoptosis induced by cisplatin in A2780 cells, while overexpression of miR-106a significantly increased antiproliferative effects and apoptosis induced by cisplatin in A2780/DDP cells. Furthermore, miR-106a inhibited cell survival and cisplatin resistance through downregulating the expression of Mcl-1. Mcl-1 was a direct target of miR-106a. These results suggest that miR-106a may provide a novel mechanism for understanding cisplatin resistance in ovarian cancer by modulating Mcl-1.
化疗耐药是晚期卵巢癌有效治疗的主要障碍。化疗耐药的机制仍知之甚少。最近，越来越多的证据表明，微小RNA（miRNA）可调节许多参与化疗的关键分子和信号通路。微小RNA-106a（miR-106a）已被证实与多种癌症相关，但其在卵巢癌及耐药性方面的作用仍有待探索。本研究旨在探讨miR-106a是否介导卵巢癌细胞系A2780对化疗药物顺铂（DDP）的耐药性。通过实时定量聚合酶链反应（real-time PCR）鉴定A2780细胞及其耐药变体A2780/DDP细胞中miR-106a的不同表达水平。采用MTT法和流式细胞术分析miR-106a对这对细胞顺铂耐药性的影响。运用实时定量聚合酶链反应、蛋白质免疫印迹法（Western blotting）和荧光素酶报告基因检测法，探究髓细胞白血病-1（Mcl-1）是否为miR-106a的靶基因。与A2780细胞相比，顺铂耐药细胞系A2780/DDP中miR-106a的表达下调。此外，敲低miR-106a可显著降低顺铂对A2780细胞的抗增殖作用及诱导凋亡作用，而过表达miR-106a则显著增强顺铂对A2780/DDP细胞的抗增殖作用及诱导凋亡作用。此外，miR-106a通过下调Mcl-1的表达抑制细胞存活和顺铂耐药性。Mcl-1是miR-106a的直接靶基因。这些结果表明，miR-106a可能通过调节Mcl-1为理解卵巢癌顺铂耐药性提供一种新机制。
