CCAAT/增强子结合蛋白α抑制人肝癌细胞内的肝刺激因子表达  

CCAAT /enhancer binding protein has a negative role in human hepatic stimulator substant expression in HepG2 cells

作　　者：吴媛[1,2] 董凌月[1,2] 安威[1,2] 

机构地区：[1]首都医科大学基础医学院细胞生物学系,北京100069 [2]肝脏保护与再生调节北京市重点实验室,北京100069

出　　处：《首都医科大学学报》2014年第5期634-639,共6页Journal of Capital Medical University

基　　金：国家自然科学基金项目(31371169);北京市属高等学校高层次人才引进与培养计划项目(CIT&TCD201404189)~~

摘　　要：目的探讨CCAAT/增强子结合蛋白α(CCAAT/enhancer binding proteinα,C/EBPα)对人肝癌细胞内肝刺激因子(hepatic stimulator substance,HSS)表达的影响及其在表皮生长因子(epidermal growth factor,EGF)抑制HSS表达过程中的作用。方法采用凝胶迁移电泳实验(electrophoretic mobility shift assay,EMSA)研究C/EBPα与HSS启动子的体外相互作用,real-time PCR和Western blotting的方法测定hHSS mRNA和蛋白质表达情况。结果 EMSA实验证实C/EBPα可以与hHSS启动子-343/-330区域内的C/EBPα结合位点结合,对hHSS表达具有负性调节作用,C/EBPαsiRNA转染入HepG2细胞后,hHSS mRNA和蛋白质表达均升高。但C/EBPα表达下降并不影响EGF对hHSS表达,而EGF不改变C/EBPα的活性和表达。结论 C/EBPα可通过C/EBP位点抑制hHSS的表达,但不参与EGF对hHSS的转录调节过程。Objective To study the site of a negative role of CCAAT/enhancer binding protein α（ C/EBPα） in human hepatic stimulator substant（ hHSS） expression and the affect of the regulation mechanism of EGF. Methods EMSAs were carried on to examine whether candidate transcription factor binds to the hHSS promoter. mRNA levels of hHSS expression were measured by real-time PCR.Protein levels of hHSS expression were measured by Western blot. Results Down-regulation of C /EBP expression significantly enhanced hHSS mRNA expression,yet did not affect EGF inhibition of hHSS mRNA expression. The results from EMSAs clearly demonstrate that C /EBP binds the C /EBP1 site. Conclusion C /EBP does not participate in EGF inhibition of hHSS mRNA,whereas it has a negative role in hHSS expression by binding the C /EBP1 site.

关 键 词：肝刺激因子 表皮生长因子 CCAAT/增强子结合蛋白α 

分 类 号：Q503[生物学—生物化学]