SAMHD1 对HBV DNA 形成的抑制作用及其机制研究

目的:研究不同肝细胞SAMHD1 表达水平及其对HBV DNA 形成的抑制作用和相关机制。方法:通过实时荧光定量PCR 和Western blot 法检测Jurkat、THP-1、HepG2、HepG2.2.15 和Huh7 细胞等细胞SAMHD1 mRNA 和蛋白表达水平;通过对HepG2.2.15 细胞转染过表达质粒和shRNA,升高或者降低SAMHD1 的表达水平,观察不同SAMHD1 表达水平对HBV DNA 水平的影响;补充不同浓度的dNTP,比较不同dNTP 浓度对HBV DNA 水平的影响。结果:肝癌细胞系有较高的SAMHD1表达水平;降低SAMHD1 可以使HBV DNA 水平升高2.3 ~ 2.8 倍,升高SAMHD1 可以使HBV DNA 降低至33% 左右(P<0.01);升高dNTP 浓度可以促进HBV DNA 的合成水平,抵消SAMHD1 的抑制作用。结论:SAMHD1 可以抑制肝癌细胞内HBV DNA 的生成,可能是通过降低细胞内dNTP 浓度实现的。

Inhibitory effect of SAMHD1 on production of HBV DNA

Objective:To study the expression levels of SAMHD1 in different liver cancer cells and the inhibition of HBV DNA production by SAMHD1.Methods:SAMHD1 mRNA and protein levels in Jurkat,THP-1,HepG2,HepG2.2.15 and Huh7 were detected by Real-time quantitative PCR and Western blot.SAMHD1 expression in HepG2.2.15 was increased by transfecting SAMHD1 over expression vectors or was inhibited by transfecting SAMHD1 specific shRNA,and then HBV DNA levels were detected.The effect of different dNTP concentration on HBV DNA production was detected also.Results:SAMHD1 were highly expressed in liver cancer cells.Decreased SAMHD1 expression could enhance HBV DNA production by 2.3-2.8 times,and increased SAMHD1 expression could inhibit HBV DNA levels by 3 times(P<0.01).Increased dNTP concentration could enhance HBV DNA production and counteract the inhibitory effect of SAMHD1.Conclusion:SAMHD1 can inhibit the production of HBV DNA in liver cancer cells by decreasing dNTP concentration.