Downregulation of MicroRNA-145 Caused by Hepatitis B Virus X Protein Promotes Expression of CUL5 and Contributes to Pathogenesis of Hepatitis B Virus-Associated Hepatocellular Carcinoma
Downregulation of MicroRNA-145 Caused by Hepatitis B Virus X Protein Promotes Expression of CUL5 and Contributes to Pathogenesis of Hepatitis B Virus-Associated Hepatocellular Carcinoma
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DOI：
10.1159/000438522
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发表时间：
2015-01-01
影响因子：
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通讯作者：
Yan, Changqing
中科院分区：
文献类型：
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作者：
Gao, Feng;Sun, Xiaoyu;Yan, Changqing
背景：B型肝炎病毒感染诱发的肝细胞癌（HCC）是我国人类健康的主要威胁。B型肝炎病毒X蛋白（HBX）是一种HBV蛋白，参与调节宿主细胞的细胞活动，并与肝癌的发生有关。方法和结果：在这项研究中，我们对53例HCC患者（25例HBV阳性病例和28例HBV阴性病例）的肿瘤组织样本进行了实时PCR，以筛选先前报道在HBV相关HCC中异常表达的候选miRNA，并发现miR-145显著下调。以下计算分析将CUL 5和RAB 5C鉴定为miR-145的虚拟靶标，而仅CUL 5通过荧光素酶报告基因测定被验证为肝细胞中miR-145的经验证的靶基因。与此结果相一致，我们发现CUL 5的mRNA和蛋白表达水平在HBV阳性的HCC中显著高于HBV阴性的HCC。体外实验表明，与对照组相比，HBX过表达的HepG 2细胞中miRNA-145的表达显著降低，CUL 5的mRNA和蛋白表达显著增加，且增殖增强。在HepG2.2.15中，我们发现与随机对照相比，用60 nM miR-145模拟物转染的H细胞的CUL 5表达和细胞生长速率均显著降低。结论：HBV感染促进细胞生长，至少部分是通过HBX诱导的miRNA-145表达下调，这是HBV相关HCC的肿瘤发生的原因。版权所有（C）2015 S. Karger AG，巴塞尔
Background: Hepatitis B viral infection-induced hepatocellular carcinoma (HCC) is a major threat to human health in China. Hepatitis B virus X protein (HBX), an HBV protein, has been reported to be involved in regulating the cellular activities of the host cells and is responsible for HCC oncogenesis. Methods and Results: In this study, we performed real-time PCR in tumor tissue samples collected from 53 HCC patients (25 HBV-positive cases and 28 HBV-negative cases) to screen the candidate miRNAs that have previously been reported to be aberrantly expressed in HBV-associated HCC and found that miR-145 was significantly downregulated. The following computational analysis identified CUL5 and RAB5C as virtual targets of miR-145, whereas only CUL5 was verified as a validated target gene of miR-145 in liver cells via luciferase reporter assay. In line with this result, we found that both the mRNA and protein expression levels of CUL5 were significantly higher in HBV-positive than in HBV-negative HCC. An in vitro experiment demonstrated a significant decrease in the expression of miRNA-145, a substantial increase in the mRNA and protein expression of CUL5, and an enhanced proliferation of HBX over-expressing HepG2 cells compared with the control. In HepG2.2.15, we found significant decreases in both the expression of CUL5 and the cell growth rate of H cells transfected with 60 nM miR-145 mimics compared with the scramble controls. Conclusion: HBV infection promotes cell growth, at least partially, through the HBX-induced downregulation of miRNA-145 expression, which is responsible for the oncogenesis of HBV-associated HCC. Copyright (C) 2015 S. Karger AG, Basel