HBx蛋白抑制DKK4表达的机制及对肝癌细胞系增殖和迁移的影响

目的 探讨乙型肝炎病毒X蛋白下调DKK4的机制及对肝癌细胞系增殖和迁移能力的影响。方法 将编码乙型肝炎病毒X蛋白的腺病毒（Ad-HBx）分别感染肝癌细胞系HepG2和SMMC7721细胞，同时设感染GFP腺病毒（Ad-GFP）为对照组，用去乙酰化酶抑制剂（TSA）处理肝癌细胞系，并用小干扰RNA-组蛋白去乙酰化酶1（si-HDAC1）及过表达DKK4的慢病毒转染肝癌细胞系。Western blot检测DKK4、HDAC1及SIRT1的表达情况。MTT实验、结晶紫实验和Transwell实验分别检测肝癌细胞系的增殖和迁移能力。结果 Ad-HBx感染肝癌细胞系后DKK4蛋白表达水平下降（P<0.05），TSA处理后DKK4蛋白表达水平回复（P<0.05）。Ad-HBx感染肝癌细胞系后，HDAC1及SIRT1蛋白水平显著升高（P<0.05）。小干扰RNA沉默HDAC1后能够恢复DKK4的表达（P<0.05），沉默HDAC1和（或）过表达DKK均能抑制肝癌细胞系的增殖和迁移能力（P<0.05）。结论 乙型肝炎病毒X蛋白通过上调HDAC1、SIRT1来抑制DKK4的表达，沉默HDAC1及过表达DKK4蛋白表达能够抑制感染Ad-HBx肝癌细胞系的增殖和迁移能力。

Mechanism of HBx Protein Inhibiting DKK4 Expression and Its Effect on Proliferation and Migration of Hepatocarcinoma Cell Lines

Objective To explore the mechanism of hepatitis B virus X protein down-regulating DKK4 and its effect on the proliferation, migration of HCC cell lines. Methods HCC cell lines HepG2 and SMMC7721 cells were infected with adenovirus encoding hepatitis B virus X protein (Ad-HBx), and GFP adenovirus (Ad-GFP) was designed as a control group. We used deacetylase inhibitor (TSA) to treat HCC cell lines and transfected HCC cell lines with small interfering RNA-histone deacetylase 1 (si-HDAC1) and lentivirus overexpressing DKK4. Western blot was used to detect the expression of DKK4, HDAC1 and SIRT1. The proliferation and migration ability of HCC lines were assessed using MTT, crystal violet experiment and Transwell experiment. Results DKK4 expression level was significantly downregulated after Ad- HBx infection (P<0.05), and its expression level was recovered after TSA treatment (P<0.05). After silencing HDAC1 with small interfering RNA, the expression of DKK4 could be restored (P<0.05), the proliferation and migration of HDAC1-silencing or/and DKK4-overexpressing cells decreased (P<0.05). Conclusion Hepatitis B virus X protein inhibits the expression of DKK4 protein by up-regulating HDAC1 and SIRT1. Silencing HDAC1 and over expressing DKK4 protein could inhibit the proliferation and migration of HCC cell lines infected with Ad-HBx.