EGCG对LPS刺激人肺腺癌A549细胞凋亡及CUGBP1蛋白表达的影响

目的:研究表没食子儿茶素-3-没食子酸酯(epigallocatechin-3-gallate,EGCG)对炎性刺激的人肺腺癌A549细胞增殖和凋亡的影响及与CUGBP1表达的关系。方法:MTT法检测EGCG和LPS刺激A549细胞增殖活性的影响;流式细胞仪检测细胞凋亡;免疫细胞化学检测EGCG对LPS刺激人肺腺癌A549细胞内CUGBP1蛋白的表达。结果:与对照组相比,LPS体外显著促进A549细胞增殖,其胞核胞质内CUGBP1表达明显增强(P0.01)。加入EGCG可拮抗LPS促A549细胞增殖的作用,促进其凋亡,明显抑制LPS刺激的A549细胞内CUGBP1的表达(P0.01)。CUGBP1蛋白定量分析可知EGCG和LPS共同孵育A549细胞4h、24h时,细胞中的CUGBP1蛋白表达量较单纯LPS作用时降低。但EGCG和LPS共同孵育A549细胞24h,A549细胞中胞核CUGBP1蛋白表达量(1210.565±3.46)较4h时胞核CUGBP1蛋白表达量(67.344±3.68)高,差异有统计学意义(t=927.164,P0.001)。结论:EGCG可能通过干扰CUGBP1基因的表达抑制炎症刺激人肺腺癌细胞A549的增殖,促进其凋亡。

Effect of EGCG on the Apoptosis and CUGBP1 Protein Expression ofHuman Lung Adenocarcinoma A549 Cells induced by LPS

Objective:To study the effects of epigallocatechin-3-gallate (EGCG) on the apoptosis and CUGBP1 expression ofhuman lung adenocarcinoma A549 cells stimulated by lipopolysaccharide (LPS).Methods:The proliferation and apoptosis of humanlung adenocarcinoma A549 cells stimulated by LPS and EGCG were detected by MTT assay and flow cytometry respectively. TheCUGBP1 protein expression of A549 cells stimulated by LPS and EGCG were examined by immunocytochemistry (ICC).Results:LPSmarkedly stimulated the proliferation of A549 cells and increased CUGBP1 protein expression in the nucleus and cytoplasm, comparedwith normal control (P<0.01); EGCG inhibited the proliferation and obviously induced the apoptosis of A549 cells treated with LPS;EGCG also markedly antagonized the CUGBP1 protein expression in nucleus of A549 cells incubated with LPS (P<0.01); Quantitativeanalysis for the CUGBP1 protein level showed that at 4h or 24h, EGCG significantly inhibited the CUGBP1 expression of A549 cellsstimulated by LPS. The relative expression amount of CUGBP1 protein stimulated by EGCG and LPS at 24 h (1210.565± 3.46) wassignificantly higher than that at 4h(67.344± 3.68) (t=927.164, P<0.001).Conclusion:EGCG can reverse the promotional effects of LPSon the A549 cell proliferation and CUGBP1 expression and induce the apoptosis.