EGCG干预LMP1激活的AP-1信号转导通路

目的　探讨EGCG对鼻咽癌细胞激活蛋白 1(AP 1)信号转导通路的干预作用 ,阐明在鼻咽癌细胞中茶多酚干预EB病毒潜伏膜蛋白 1(LMP1)活化的AP 1信号转导通路中靶分子的机制。方法　采用EB病毒阴性及阳性的鼻咽癌细胞系CNE1和CNE1 LMP1细胞。利用四甲基偶氮唑蓝(MTT)法观察EGCG对CNE1和CNE1 LMP1细胞的生存率的影响。采用瞬间转染及报道基因法观察EGCG对AP 1活性的作用。利用间接免疫荧光法观察EGCG对JNK核移位的影响 ,再分别提取CNE1和CNE1 LMP1的胞浆及胞核蛋白 ,Westernblot分析EGCG抑制JNK的核移位后 ,胞浆及胞核蛋白中JNK的变化。采用Westernblot分析EGCG对c Jun的磷酸化水平的影响。采用瞬间转染及报道基因法观察EGCG对cyclinD1启动子活性的影响 ,并用Westernblot分析EGCG对cyclinD1蛋白表达的作用。结果　EGCG对鼻咽癌细胞的抑制作用有剂量依赖性 ,并可抑制AP 1的活性。EGCG能抑制JNK的核移位 ,并抑制c Jun的磷酸化。EGCG对AP 1信号通路下游的靶基因cyclinD1的启动子活性及其蛋白表达都有抑制作用。结论　EGCG对信号转导通路上的AP 1、JNK、c Jun、cyclinD1多个靶点分子具有干预作用。LMP1是EB病毒这种编码的蛋白 ,因此 ,EGCG抑制与病毒相联系的信号转导通路 ,可能是EGCG抑制与病毒相关的肿瘤的分子机

Epigallocatechin-3-gallate interferes with EBV-encoding AP-1 signal transduction pathway

Objective To elucidate the interference effect of Epigallocatechin-3- Gallate (EGCG) on targets of Activator Protein-1(AP-1)signal transduction path way activated by EB virus encoded latent membrane protein 1 in nasopharyngeal ca rcinoma (NPC) cell lines. Methods Survival rate of cells was determined by MTT assay. AP-1 and CyclinD1 activation were analyzed by promoter luciferase r e porter system. Nuclear translocation of JNK was analyzed by indirect immunofluor escence. Protein expression and phosphorylation were observed by Western blot. Results EGCG inhibited the survival of CNE1 and CNE-LMP1 cells and the activity of AP- 1 caused by LMP1 in CNE-LMP1 cells. EGCG also inhibi te d the nuclear translocation of JNK and the phosphorylation of c-Jun. It also in hibited cyclinD1 promoter activity and cyclinD1 expression. Conclusion EGCG inhi bits AP-1,JNK,c-Jun and cyclinD1 which are key targets on AP-1 signal trans duc tion pathway. The results may explain the molecular mechanism of action of EGCG against nasopharyngeal carcinoma.