COX-2在乙肝病毒X蛋白（HBx）促进肝癌细胞和肝细胞增殖中的作用

乙型肝炎病毒（hepatitis B virus, HBV）X蛋白（HBx）对肝癌的发生发展具有十分重要的作用．大量研究结果表明，与花生四烯酸代谢相关的磷脂酶COX-2与肿瘤细胞的增殖密切相关．为了阐明COX-2在HBx促进肝细胞增殖中的作用，在前期应用基因芯片方法检测发现稳定转染HBx 基因的肝癌细胞H7402-X中COX-2基因表达明显上调的基础上，本研究应用免疫印迹技术在蛋白表达水平上获得了相同的结果．进而，应用COX-2的特异性抑制剂Indo分别作用H7402-X细胞和L-O2-X细胞（稳定转染HBx 基因的人永生化L-O2肝细胞），观察HBx蛋白是否通过COX-2促进肝癌细胞或肝细胞增殖．BrdU掺入实验和流式细胞仪检测结果显示，50 μmol/L的Indo可明显抑制H7402-X细胞和L-O2-X细胞的增殖．本研究结果提示，HBx可通过COX-2所介导的花生四烯酸代谢促进肝癌细胞和肝细胞增殖．

Effect of COX-2 on Proliferation of Hepatoma and Liver Cells Mediated by Hepatitis B Virus X Protein

Infection of hepatitis B virus (HBV) X protein (HBx) causes the development of hepatocellular carcinoma (HCC). Many reports showed that cyclooxygenase (COX-2) involved in arachidonic acid metabolism is closely related to the proliferation of tumor cells. In order to reveal the effect of COX-2 on promoting liver cell proliferation meditaed by HBx, based on our previous finding that COX-2 was up-regulated by microarray assay in H7402-X cells stably transfected with HBx gene, we obtained the consistent result by Western blot analysis at protein level. Moreover, we investigated the effect of 50 μmol/L Indo, a specific inhibitor of COX-2, on H7402-X cells and human immortalized liver L-O2-X cells stably transfected with HBx gene to observe whether HBx enhances proliferation of hepatoma or liver cells via COX-2. BrdU incorporation assay and flow cytometry analysis showed that Indo was able to promote the proliferation of H7402-X cells and L-O2-X cells. Thus, our data demonstrated that HBx enhances the proliferation of hepatoma cells and liver cells through arachidonic acid metabolism mediated by COX-2.