Wang Zhao, Ceniccola Kristin, Florea Liliana, Wang Bi-Dar, Lee Norman H, Kumar Ajit
Department of Biochemistry, The George Washington University, Washington, DC USA.
Department of Pharmacology, and Program in Molecular Oncology, The George Washington University, Washington, DC USA.
Infect Agent Cancer. 2015 Jul 8;10:19. doi: 10.1186/s13027-015-0014-0. eCollection 2015.
Hepatitis C virus (HCV) infection is an established cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC); however, it is unclear if the virus plays a direct role in the development of HCC. Hepatocyte nuclear factor 4α (HNF4α) is critical determinant of epithelial architecture and hepatic development; depletion of HNF4α is correlated with oncogenic transformation. We explored the viral role in the inhibition of HNF4α expression, and consequent induction of tumor-promoting genes in HCV infection-associated HCC.
Western blot analysis was used to monitor the changes in expression levels of oncogenic proteins in liver tissues from HCV-infected humanized mice. The mechanism of HNF4α depletion was studied in HCV-infected human hepatocyte cultures in vitro. Targeting of HNF4α expression by viral non-coding RNA was examined by inhibition of Luciferase HNF4α 3'-UTR reporter. Modulation of invasive properties of HCV-infected cells was examined by Matrigel cell migration assay.
Results show inhibition of HNF4α expression by targeting of HNF4α 3'-UTR by HCV-derived small non-coding RNA, vmr11. Vmr11 enhances the invasive properties of HCV-infected cells. Loss of HNF4α in HCV-infected liver tumors of humanized mice correlates with the induction of epithelial to mesenchymal transition (EMT) genes.
We show depletion of HNF4α in liver tumors of HCV-infected humanized mice by HCV derived small non-coding RNA (vmr11) and resultant induction of EMT genes, which are critical determinants of tumor progression. These results suggest a direct viral role in the development of hepatocellular carcinoma.
丙型肝炎病毒（HCV）感染是慢性肝炎、肝硬化和肝细胞癌（HCC）的既定病因；然而，尚不清楚该病毒在HCC的发生发展中是否起直接作用。肝细胞核因子4α（HNF4α）是上皮结构和肝脏发育的关键决定因素；HNF4α的缺失与致癌转化相关。我们探讨了病毒在HCV感染相关HCC中抑制HNF4α表达以及随后诱导促肿瘤基因方面的作用。
采用蛋白质免疫印迹分析监测HCV感染的人源化小鼠肝脏组织中致癌蛋白表达水平的变化。在体外HCV感染的人肝细胞培养物中研究HNF4α缺失的机制。通过抑制荧光素酶HNF4α 3'-UTR报告基因检测病毒非编码RNA对HNF4α表达的靶向作用。通过基质胶细胞迁移试验检测HCV感染细胞侵袭特性的调节。
结果显示，HCV衍生的小非编码RNA vmr11通过靶向HNF4α 3'-UTR抑制HNF4α表达。Vmr11增强了HCV感染细胞的侵袭特性。人源化小鼠HCV感染性肝肿瘤中HNF4α的缺失与上皮-间质转化（EMT）基因的诱导相关。
我们发现HCV衍生的小非编码RNA（vmr11）导致HCV感染的人源化小鼠肝肿瘤中HNF4α缺失，并进而诱导EMT基因，而EMT基因是肿瘤进展的关键决定因素。这些结果表明病毒在肝细胞癌的发生发展中起直接作用。
