Department of Cancer Research, Key Laboratory of Molecular Microbiology and Technology of Ministry of Education, Institute for Molecular Biology, Nankai University, Tianjin 300071, China.
Acta Pharmacol Sin. 2011 Sep;32(9):1173-80. doi: 10.1038/aps.2011.52. Epub 2011 Aug 1.
To investigate the mechanism underlying the increase of hepatoma cell proliferation by hepatitis B virus X protein (HBx).
HepG2, H7402 and HepG2.2.15 cells, which constitutively replicated hepatitis B virus were used. The effects of HBx on hepatoma cell proliferation were examined using 5-ethynyl-2-deoxyuridine (EdU) incorporation assay and MTT assay. The expression level of MEKK2 was measured using RT-PCR, Western blot and luciferase reporter gene assay. The activity of activator protein 1 (AP-1) was detected using luciferase reporter gene assay. The phosphorylation levels of JNK and c-Jun were measured using Western blot. The expression levels of HBx and MEKK2 in 11 clinical hepatocellular carcinoma (HCC) tissues were measured using real time PCR and Western blot. In addition, the expression of MEKK2 in 95 clinical HCC tissues was examined using immunohistochemistry.
HBx significantly enhanced HepG2-X cell proliferation. In HepG2-X, H7402-X and HepG2.2.15 cells, the expression level of MEKK2 was remarkably increased. In HepG2.2.15 cells, HBx was found to activate JNK and AP-1, which were the downstream effectors of MEKK2 in HepG2-X and HepG2.2.15 cells. In 11 clinical HCC tissues, both HBx and MEKK2 expression levels were remarkably increased, as compared to those in the corresponding peritumor tissues. In 95 clinical HCC tissues, the rate of detection of MEKK2 was 85.3%.
HBx promotes hepatoma cell proliferation via upregulating MEKK2, which may be involved in hepatocarcinogenesis.
研究乙型肝炎病毒 X 蛋白（HBx）增加肝癌细胞增殖的机制。
使用持续复制乙型肝炎病毒的 HepG2、H7402 和 HepG2.2.15 细胞，通过 5-乙炔基-2-脱氧尿苷（EdU）掺入测定和 MTT 测定检测 HBx 对肝癌细胞增殖的影响。使用 RT-PCR、Western blot 和荧光素酶报告基因测定测定 MEKK2 的表达水平。使用荧光素酶报告基因测定检测激活蛋白 1（AP-1）的活性。使用 Western blot 测定 JNK 和 c-Jun 的磷酸化水平。使用实时 PCR 和 Western blot 测定 11 例临床肝癌（HCC）组织中 HBx 和 MEKK2 的表达水平。此外，使用免疫组织化学法检测 95 例临床 HCC 组织中 MEKK2 的表达。
HBx 显著增强了 HepG2-X 细胞的增殖。在 HepG2-X、H7402-X 和 HepG2.2.15 细胞中，MEKK2 的表达水平显著增加。在 HepG2.2.15 细胞中，发现 HBx 激活了 JNK 和 AP-1，它们是 HepG2-X 和 HepG2.2.15 细胞中 MEKK2 的下游效应物。在 11 例临床 HCC 组织中，HBx 和 MEKK2 的表达水平均显著升高，与相应的癌旁组织相比。在 95 例临床 HCC 组织中，MEKK2 的检出率为 85.3%。
HBx 通过上调 MEKK2 促进肝癌细胞增殖，这可能与肝癌发生有关。
