Key Laboratory for Experimental Teratology of Ministry of Education and Institute of Immunology, Shandong University School of Medicine, 44 Wenhua Xi Road, Jinan, Shandong 250012, PR China.
Int J Biochem Cell Biol. 2013 Jul;45(7):1174-85. doi: 10.1016/j.biocel.2013.03.015. Epub 2013 Mar 27.
Hepatitis B virus core protein can regulate viral replication and host gene expression. However, it is unclear whether and how hepatitis B virus core protein regulates hepatocellular carcinoma cell proliferation. Induction of hepatitis B virus core protein over-expression significantly enhanced the proliferation of hepatocellular carcinoma cells, while knockdown of hepatitis B virus core protein expression inhibited the proliferation of hepatocellular carcinoma cells. Altered hepatitis B virus core protein expression significantly changed the growth of implanted hepatocellular carcinoma in vivo. Microarray analysis indicated that hepatitis B virus core protein up-regulated human telomerase reverse transcriptase expression, which was further validated by over-expression and knockdown assays in vitro. Furthermore, knockdown of human telomerase reverse transcriptase expression mitigated the hepatitis B virus core protein-enhanced hepatocellular carcinoma cell proliferation and clone formation in vitro. Luciferase assays indicated that hepatitis B virus core protein enhanced the promoter activity of human telomerase reverse transcriptase, which was dependent on the binding of c-Ets2 to the promoter region between -192 and -187. In addition, hepatitis B virus core protein enhanced human telomerase reverse transcriptase transcription in HepG2 cells, but not in the c-Ets2-silencing HepG2 cells. Moreover, hepatitis B virus core protein promoted c-Ets2 nuclear translocation. Finally, significantly higher levels of human telomerase reverse transcriptase expression and nuclear c-Ets2 accumulation were detected in hepatitis B virus core protein-positive hepatocellular carcinoma samples. Our findings demonstrate that hepatitis B virus core protein promotes hepatocellular carcinoma cell proliferation by up-regulating the c-Ets2-dependent expression of human telomerase reverse transcriptase.
乙型肝炎病毒核心蛋白可调节病毒复制和宿主基因表达。然而，尚不清楚乙型肝炎病毒核心蛋白是否以及如何调节肝癌细胞的增殖。诱导乙型肝炎病毒核心蛋白过表达显著增强肝癌细胞的增殖，而敲低乙型肝炎病毒核心蛋白表达则抑制肝癌细胞的增殖。乙型肝炎病毒核心蛋白表达的改变显著改变了体内植入肝癌的生长。微阵列分析表明，乙型肝炎病毒核心蛋白上调了人类端粒酶逆转录酶的表达，体外过表达和敲低实验进一步验证了这一点。此外，敲低人类端粒酶逆转录酶的表达减轻了乙型肝炎病毒核心蛋白增强的肝癌细胞增殖和体外克隆形成。荧光素酶测定表明，乙型肝炎病毒核心蛋白增强了人类端粒酶逆转录酶的启动子活性，这依赖于 c-Ets2 与 -192 至-187 之间启动子区域的结合。此外，乙型肝炎病毒核心蛋白增强了 HepG2 细胞中的人类端粒酶逆转录酶转录，但在 c-Ets2 沉默的 HepG2 细胞中则没有。此外，乙型肝炎病毒核心蛋白促进 c-Ets2 核易位。最后，在乙型肝炎病毒核心蛋白阳性的肝癌样本中检测到更高水平的人类端粒酶逆转录酶表达和核 c-Ets2 积累。我们的研究结果表明，乙型肝炎病毒核心蛋白通过上调 c-Ets2 依赖性人类端粒酶逆转录酶的表达促进肝癌细胞的增殖。
