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目的 探讨蛋白激酶C在表没食子儿茶素没食子酸酯 (EGCG)诱导大肠癌LoVo细胞凋亡中的调控作用。方法 在有或没有蛋白激酶C激活剂PMA预处理LoVo细胞的情况下 ,用流式细胞术、Westernblot分析以及蛋白激酶C检测试剂盒检测EGCG处理LoVo细胞前后其细胞内多种蛋白激酶C同工酶表达水平和细胞内蛋白激酶C总活性的变化。结果 PMA(10 0nmol·L-1)预处理LoVo细胞 3h ,可部分地抑制EGCG诱导的LoVo细胞凋亡。流式细胞术和Westernblot分析显示EGCG处理LoVo细胞后可引起该细胞内多种蛋白激酶C同工酶包括cPKCα、βⅠ、βⅡ、nPKCε和aPKCξ表达水平下调 ,并呈时间效应关系 ;而细胞内蛋白激酶C总活性无明显变化。结论 蛋白激酶C参与了EGCG诱导LoVo细胞凋亡的调控作用 ,主要是通过下调多种蛋白激酶C同工酶表达水平而不是通过影响细胞内蛋白激酶C总活性而发挥作用
Objective To investigate the regulation of protein kinase C in epigallocatechin-3-gallate (EGCG)-induced apoptosis of colon cancer LoVo cells. Methods Pretreatment of LoVo cells with or without the protein kinase C activator PMA, flow cytometry, Western blot analysis, and protein kinase C detection kits were used to detect intracellular PKC in LoVo cells before and after treatment with EGCG. The level of enzyme expression and changes in intracellular protein kinase C total activity. Results The pretreatment of LoVo cells with PMA (100 nmol·L-1) for 3 h partially inhibited the apoptosis of LoVo cells induced by EGCG. Flow cytometry and Western blot analysis showed that treatment of LoVo cells with EGCG resulted in the down-regulation of multiple protein kinase C isoenzymes including cPKCα, βI, βII, nPKCε and aPKCξ in a time-dependent manner; intracellular proteins There was no significant change in the total activity of kinase C. Conclusion Protein kinase C is involved in the regulation of apoptosis of LoVo cells induced by EGCG, mainly through down-regulating the expression levels of multiple protein kinase C isoenzymes, but not by affecting the total activity of intracellular protein kinase C.