JNK/AP-1信号通路在As_2O_3诱导乳腺癌细胞凋亡中的作用

The role of JNK/AP-1 signal pathway in As_2O_3 induced apoptosis in the human breast cancer cells

目的探讨c-Jun N端激酶(JNK)信号通路在As2O3诱导乳腺癌细胞凋亡中的作用。方法体外培养MCF7细胞,以As2O3为刺激源,溴化丙锭(PI)染色结合流式细胞术方法检测细胞周期及细胞凋亡;双荧光素酶报告基因法检测MCF7细胞中AP-1的诱导活化;Western印迹法检测JNK、c-Jun的诱导活化及Fra-1的蛋白表达。结果 As2O3可显著诱导MCF7细胞凋亡并导致细胞周期行进阻滞;As2O3可诱导JNK持续性高强度表达,转录因子AP-1的转录激活活性上调;As2O3可诱导c-Jun活化并诱导Fra-1表达;转染c-Jun显性负性突变体TAM67或Fra-1shRNA可有效降低As2O3诱导的乳腺癌细胞凋亡。结论 JNK/AP-1途径是介导As2O3诱导乳腺癌细胞凋亡反应的重要信号通路。

Objective To explore the role of c-Jun N-terminal kinase（JNK） signaling pathway in mediating the apoptotic effect in human breast cancer cells exposed to arsenic trioxide（As2O3,arsenite）.Methods MCF7 cells were treated with arsenite.The cell cycle distribution and the apoptosis were detected by flow cytometric analysis with PI staining of the nuclei.Luciferase assay was used to detect the activation of the transcriptional factor of activated protein-1（AP-1） in the MCF7 cells.The induced activation of JNK,c-Jun and the expression of Fra-1 were tested by Western blot assay.Results Both growth arrest and apoptosis could be induced by arsenite in MCF7 cells,along with the strong and persistent activation of JNK and AP-1 under the same conditions.Moreover,the phosphorylation and the expression of the AP-1 components,c-Jun and Fra-1,could be induced by arsenite in MCF7 cells.Arsenite-induced apoptosis was partially attenuated in the DN-c-Jun（TAM67） or Fra-1shRNA-transfected MCF7 cells.Conclusion JNK/AP-1 is a critical signal pathway in mediating arsenite-induced apoptosis in the human breast cancer cells.