目的:探讨肿瘤坏死因子（tumor necrosis factorα, TNFα）诱导血管内皮生长因子(vascular endothelial growth factor，VEGF)表达的机制。方法：以20 ng/ml TNFα处理MCF7细胞，用Western blotting检测MAPK(JNK，p38，ERK)信号通路中蛋白磷酸化水平的变化以及AP1家族(cJun，JunB，cFos，Fra1，Fra2，JunD)的蛋白表达及磷酸化水平的变化；以免疫共沉淀法检测激活后的AP1存在形式；以RTPCR以及Western blotting检测VEGF mRNA和蛋白表达水平；以MAPK抑制剂预处理后，检测VEGF蛋白表达水平；运用ChIP的方法验证pcJun结合在VEGF启动子区。结果： TNFα通过激活JNK信号转导通路活化AP1；被TNFα激活后AP1以pcJuncJun和pcJunJunB同源二聚体形式存在；TNFα通过激活转录因子AP1促进VEGF的转录，并增强VEGF的蛋白表达水平；pcjun通过与VEGF启动子AP1结合参与对VEGF转录的调控。结论：在TNFα作用下，AP1通过pcjun同源二聚体结合在VEGF启动子的AP1结合位点上，直接对VEGF转录进行调控

Objective: To investigate the mechanism by which tumor necrosis factorα (TNFα) induces expression of vascular endothelial growth factor(VEGF) in MCF7 cells. Methods: MCF7 cells were treated with TNFα (20 ng/ml) for different time periods. Western blotting was used to detect the phosphorylation of MAPK pathway proteins (JNK, P38, and ERK) and the expression and phosphorylation of AP1 family members(cJun，JunB，cFos，Fra1，Fra2，JunD). The activation of AP1 was detected by immunoprecipitation(IP). RTPCR and Western blotting were used to detect the VEGF mRNA and protein expression. The VEGF protein expression was also detected after pretreatment with inhibitor of MAPK. ChIP method was used to verify the binding of pcJun to the promoter region of VEGF. Results: TNFα activated AP1 through JNK signal pathway. AP1 existed in the form of pcJuncJun and pcJunJunB homodimer after activation. TNFα increased VEGF transcription by activating transcriptional factor AP1 and result in increased expression of VEGF protein. Pcjun regulated the transcription of VEGF through binding to the AP1 site of VEGF. Conclusion: TNFα can mediate the transcription of VEGF through a AP1dependent pathway.

国家自然科学基金资助项目（No.30772474）;江苏省自然科学基金资助项目（No.BK2008477)