乙型肝炎病毒X蛋白促进甲胎蛋白表达的分子机制  

The molecular mechanism of hepatitis B virus X protein promoting the expression of alpha-fetoprotein

作　　者：张超 周伟燕[1] 汪静[1] 张江涛[1] 张传宝[1] Zhang Chao;Zhou Weiyan;Wang Jing;Zhang Jiangtao;Zhang Chuanbao(National Center for Clinical Laboratories,Beijing Hospital,National Center of Gerontology,Institute of Geriatric Medicine,Chinese Academy of Medical Sciences,Beijing 100730,China)

机构地区：[1]北京医院国家老年医学中心国家卫生健康委临床检验中心中国医学科学院老年医学研究院,100730

出　　处：《中华实验和临床病毒学杂志》2020年第6期588-593,共6页Chinese Journal of Experimental and Clinical Virology

基　　金：国家自然科学基金(82003809);北京医院"科技新星"(BJ-2020-087);北京医院博士启动基金(BJ-2019-148);清华211学科建设(201920102201)。

摘　　要：目的探讨乙肝病毒编码X蛋白促进甲胎蛋白表达的分子机制。方法非参数检验-秩和检验评估肝癌患者HBV感染与否与AFP表达水平间的相关性;在PLC/PRF/5肝癌细胞系中转染HBV、HBx及P53真核表达质粒,36 h Western blot和qRT-PCR分别在蛋白质和mRNA水平检测HBV和HBx对P53和AFP表达的影响,以及P53对AFP表达的影响;在PLC/PRF/5细胞中转染包含AFP基因启动子和沉默子的荧光素酶报告质粒,通过检测荧光素酶活性改变明确沉默子区域,再将包含沉默子的报告载体与HBV/HBx质粒共转染PLC/PRF/5细胞,通过检测荧光素酶活性的改变验证HBV/HBx对AFP基因沉默子区域的作用;用ChIP实验验证P53在AFP基因沉默子区域的结合,并证实HBx对P53与作用序列结合能力的影响。结果统计分析发现HBV感染与AFP表达之间存在明显相关性,HBV阳性肝癌患者的血清AFP值总体中位数为296.8 ng/ml,而HBV阴性患者的AFP总体中位数为71.5 ng/ml(P=0.02),HBV阳性肝癌患者的AFP表达水平明显高于HBV阴性肝癌患者;P53可以抑制AFP表达(P<0.001),而HBV和HBx均能抑制P53表达(P=0.0011、P=0.0027),并促进AFP表达(P=0.0014、P<0.001);HBV和HBx可以作用于AFP基因沉默子区域,促进基因转录(P<0.001、P=0.0019;P=0.0046、P=0.0015);P53与AFP基因沉默子的结合作用能够被HBx所够削弱。结论 HBx可通过抑制P53表达,并且抑制P53在AFP基因沉默子区域的结合,以此促进AFP基因转录,并进一步促进AFP蛋白表达。Objective To investigate the molecular mechanism of hepatitis b virus X protein promoting the expression of alpha-fetoprotein.Methods Wilcoxon rank sum test was used to evaluate the correlation between HBV infection and AFP expression level in patients with liver cancer.HBV,HBx and P53 expression plasmids were transfected to PLC/PRF/5 hepatoma cell lines.After culture for 36 h,Western Blot and qRT-PCR were used to detect the effects of HBV and HBx on the expression of P53 and AFP,as well as the effects of P53 on the expression of AFP,respectively,at the protein and mRNA levels.Luciferase reporter vectors containing AFP gene promoters and silencers were transfected into PLC/PRF/5 cells,and the silencer region was determined by luciferase activity detection.Then,the silencer region was co-transfected into PLC/PRF/5 cells with HBV/HBx plasmid.The effect of HBx on AFP gene silencer region was verified by detection of changes in luciferase activity.ChIP experiment was used to verify the binding of P53 in the AFP gene silencer region,as well as the effect of HBx on the binding ability of P53 to the reaction element.Results statistical analysis showed that there was a significant correlation between HBV infection and AFP expression.The total median of serum AFP in HBV-positive liver cancer patients was 296.8ng/ml,while the total median of AFP in HBV-negative liver cancer patients was 71.5ng/ml(P=0.02).The expression level of AFP in HBV-positive liver cancer patients was significantly higher than that in HBV-negative liver cancer patients.P53 can inhibit the expression of AFP(P=0.0003),while HBV and HBx can inhibit the expression of P53(P=0.0011,0.0027)and promote the expression of AFP(P=0.0014,0.0005).HBV and HBx can act on AFP gene silencer region and promote gene transcription(P=0.00045,0.0019;P=0.0046,0.0015).HBx can weaken the inhibitory effect of P53 on AFP gene silencer.Conclusions HBx can promote the transcription and expression of AFP gene by inhibiting the expression of P53 and its binding with the AFP gene sil

关 键 词：乙肝病毒 乙肝病毒X蛋白 甲胎蛋白 P53 转录调控 

分 类 号：R512.62[医药卫生—内科学] R735.7[医药卫生—临床医学]