HBV DNA聚合酶(HBp)通过下调Fas表达抑制肝癌细胞的凋亡  

HBV polymerase inhibits apoptosis of hepatoma cell by down-regulating Fas expression

作　　者：关妘[1] 韩秋菊[1] 侯召华[1] 张建[1] 张彩[1] 

机构地区：[1]山东大学药学院免疫药理与免疫治疗研究所,济南250012

出　　处：《现代免疫学》2013年第3期202-207,共6页Current Immunology

基　　金：国家自然科学基金资助项目(81273220;31200651);国家重点基础研究发展计划(973)资助项目(2013CB944901);山东省优秀中青年科研奖励基金(BS2010YY033)

摘　　要：为了研究HBV感染对肝癌细胞凋亡的影响,我们首先观察肝癌细胞HepG2和HepG2.2.15细胞凋亡相关蛋白的表达差异,继而构建了HBV全长基因组以及HBV各元件HBx、HBc、HBs、HBp的表达载体,并将其分别转染到HepG2细胞。采用流式细胞术和普通PCR的方法检测不同转染组中Fas蛋白水平及基因水平表达;Annexin V/PI双染法检测细胞的凋亡,定量PCR检测凋亡相关基因mRNA的表达变化;并用CFSE/7AAD方法检测HepG2细胞对NK杀伤敏感性的变化。数据显示:含有HBV全基因组的HepG2.2.15Fas表达明显低于无HBV感染的HepG2细胞;转染HBp元件后,HepG2细胞中Fas表达下调最明显;并且细胞凋亡比例显著下降,抗凋亡基因Bcl-2和Bcl-xl的表达上升,促凋亡基因Bax、Bak和Bad的表达下降。而且,转染HBp元件显著降低HepG2细胞对NK细胞杀伤的敏感性。这说明在HBV病毒感染过程中,HBp基因除发挥DNA聚合酶的作用外,还可通过下调Fas表达抑制肝细胞的凋亡、降低其对NK细胞的杀伤敏感性,此可能为HBV+肝癌发生发展更易发生免疫逃逸的原因之一。In order to explore the influence of HBV infection on apoptosis of bepatoma cell, we first observed the differences of Fas expression on HepG2 and HepG2. 2. 15 cell lines. Then we constructed expression vectors containing full-length HBV, HBV x gene （HBx）, HBV core gene （HBc）, HBV s gene （HBs） and HBV polymerase gene （HBp）, and thransfected them respectively into HepG2 cells. The protein and mRNA levels of Fas expression were detected by FACS and RT-PCR. The apoptosis of HepG2 cells was assayed with Annexin V/PI double staining. The expression of anti-apoptosis genes Bcl-2 and Bcl xl and pro-apotosis gene Bax, Bad and Bak were determined by RT-PCR. The lysis of NK cells was assayd by CFSE/7AAD method. The result showed that fullqength HBV or HBp could down-regulate Fas expression of HepG2 cell significantly. Anti- apoptosis genes Bcl-2 and Bel xl were induced and pro-apotosis gene Bax, Bad and Bak were inhibited with HBp transfection. These results suggest that HBp functions not only as DNA ploymerse, but also inhibits apoptosis of hepatoma cell by down- regulating Fas expression, which might be one of the mechanisms for HBV＋ heptoma cell to escape from iramunosurveillance.

关 键 词：HBV 凋亡 HBp FAS 

分 类 号：R392.5[医药卫生—免疫学]