Shi Liang, Chen Zhan-Guo, Wu Li-Li, Zheng Jian-Jian, Yang Jian-Rong, Chen Xiao-Fei, Chen Zeng-Qiang, Liu Cun-Li, Chi Sheng-Ying, Zheng Jia-Ying, Huang Hai-Xia, Lin Xiang-Yang, Zheng Fang
Center for Gene Diagnosis, Zhongnan Hospital of Wuhan University, Wuhan, China E-mail :
Asian Pac J Cancer Prev. 2014;15(23):10439-44. doi: 10.7314/apjcp.2014.15.23.10439.
Many chemotherapeutic agents have been successfully used to treat hepatocellular carcinoma (HCC); however, the development of chemoresistance in liver cancer cells usually results in a relapse and worsening of prognosis. It has been demonstrated that DNA methylation and histone modification play crucial roles in chemotherapy resistance. Currently, extensive research has shown that there is another potential mechanism of gene expression control, which is mediated through the function of short noncoding RNAs, especially for microRNAs (miRNAs), but little is known about their roles in cancer cell drug resistance. In present study, by taking advantage of miRNA effects on the resistance of human hepatocellular carcinoma cells line to cisplatin, it has been demonstrated that miR-340 were significantly downregulated whereas Nrf2 was upregulated in HepG2/ CDDP (cisplatin) cells, compared with parental HepG2 cells. Bioinformatics analysis and luciferase assays of Nrf2-3'-untranslated region-based reporter constructor indicated that Nrf2 was the direct target gene of miR- 340, miR-340 mimics suppressing Nrf2-dependent antioxidant pathway and enhancing the sensitivity of HepG2/ CDDP cells to cisplatin. Interestingly, transfection with miR-340 mimics combined with miR-340 inhibitors reactivated the Nrf2 related pathway and restored the resistance of HepG2/CDDP cells to CDDP. Collectively, the results first suggested that lower expression of miR-340 is involved in the development of CDDP resistance in hepatocellular carcinoma cell line, at least partly due to regulating Nrf2-dependent antioxidant pathway.
许多化疗药物已成功用于治疗肝细胞癌（HCC）；然而，肝癌细胞中化疗耐药性的产生通常会导致复发和预后恶化。已证明DNA甲基化和组蛋白修饰在化疗耐药中起关键作用。目前，广泛的研究表明存在另一种基因表达控制的潜在机制，其通过短链非编码RNA的功能介导，特别是微小RNA（miRNA），但关于它们在癌细胞耐药性中的作用知之甚少。在本研究中，利用miRNA对人肝癌细胞系对顺铂耐药性的影响，已证明与亲本HepG2细胞相比，miR-340在HepG2/CDDP（顺铂）细胞中显著下调，而Nrf2上调。基于Nrf2-3'-非翻译区的报告基因构建体的生物信息学分析和荧光素酶测定表明，Nrf2是miR-340的直接靶基因，miR-340模拟物抑制Nrf2依赖性抗氧化途径并增强HepG2/CDDP细胞对顺铂的敏感性。有趣的是，用miR-340模拟物与miR-340抑制剂联合转染可重新激活Nrf2相关途径并恢复HepG2/CDDP细胞对顺铂的耐药性。总体而言，结果首次表明miR-340的低表达参与了肝癌细胞系中顺铂耐药性的发展，至少部分是由于调节Nrf2依赖性抗氧化途径。
