表达HCV NS3蛋白肝细胞中ERK与NF-κB信号转导通路间的cross-talk研究

Cross-talk between ERK and NF-κB signal transduction pathways in the hepatocytes expressing hepatitis C virus nonstructural protein 3

目的:研究表达丙型肝炎病毒非结构蛋白3(hepatitis C virus non-structural protein3,HCVNS3)的肝细胞中细胞外信号调节激酶(extracellular signal-regulated kinase,ERK)与核因子κB(nuclear fac-torκB,NF-κB)信号转导通路间的cross-talk。方法:真核表达质粒pcDNA3.1-NS3转染人源永生化肝细胞系QSG7701,建立稳定表达HCV NS3蛋白的细胞株QSG7701/NS3。在丝裂原活化蛋白激酶的激酶(MAP kinase kinase,MEK)抑制剂PD98059(0,30,50,100μmol/L)处理细胞QSG7701/NS3前后,利用Western免疫印迹检测ERK的磷酸化水平及细胞周期素D1(cyclin D1)蛋白的表达;凝胶电泳阻滞迁移试验检测转录激活因子1(activator protrin1,AP-1)、NF-κB等转录因子活性的改变;流式细胞术检测细胞周期各期百分数的改变;MTT比色法观察其对细胞增殖的影响。结果:HCV NS3蛋白能上调QSG7701细胞的ERK磷酸化水平及cyclin D1的表达水平;PD98059抑制HCV NS3蛋白介导的细胞增殖,下调AP-1和NF-κB的活性及cyclin D1的表达。结论:在表达HCV NS3蛋白的肝细胞中,ERK抑制剂能抑制肝细胞增殖,并呈明显的剂量依赖关系。ERK与NF-κB信号转导通路间可能存在cross-talk,并在肝细胞的增殖和恶性转化中发挥协同作用。

Objective To explore the cross-talk between extracellular signal-regulated kinase （ ERK ） and nuclear factor （ NF-κB ） signal transduction pathways in the hepatocytes expressing hepatitis C virus nonstructural protein 3 （HCV NS3）. Methods A cell line QSG7701/NS3, which stably expressed HCV NS3 protein, was constructed by transfecting plasmid pcDNA3. 1-NS3 into a human immortalized hepatocyte line QSG7701. Before and after QSG7701/NS3 cells were treated by MEK inhibitor PD98059, the phosphorylation level of ERK and the expression of cyclin D1 protein were detected by Western blot; the DNA binding activities of activator protein 1 （ AP-1 ） and NF-κB were evaluated with electrophoretic mobility shift assay （EMSA）. Cell cycles were measured by flow cytometry （ FCM ） ; the effects of PD98059 on the cell proliferation were determined by MTT assay. Results HCV NS3 protein could up-regulate the phosphorylation of ERK and the expression level of cyclin D1 in QSG7701 cells. PD98059 could inhibit the cell proliferation mediated by HCV NS3 protein, down-regulate the activities of AP-1 and NF-κB, and suppress the expression of cyclin D 1. Conclusion The inhibition of ERK can suppress the DNA binding activity of NF-κB and the cell proliferation mediated by HCV NS3 protein in a dose-dependent manner. There may be a cross-talk between ERK and NF-κB signal transduction pathways, which may exert synergistic action on the proliferation and malignant transformation of hepatocytes. Key words：