自噬增强拮抗褪黑素诱导的胃癌细胞增殖抑制作用

Enhancement of autophagy antagonizes melatonin-induced inhibition of gastric cancer cells proliferation

目的探究自噬在褪黑素(melatonin,MLT)抑制胃癌细胞增殖中的作用。方法荷胃癌小鼠24只,随机分为对照组、不同剂量褪黑素干预组,给药1周后取肿瘤组织进行体积测量、电镜观察和细胞自噬相关蛋白beclin-1、LC3-Ⅱ的表达检测。将小鼠前胃癌MFC细胞分为对照组、MLT组、3-甲基腺嘌呤(3-methyl adenine,3-MA)组、MLT+3-MA联合给药组,给药24h后行细胞增殖率CCK-8法检测、电镜观察、beclin-1和LC3-Ⅱ表达检测。结果在荷癌小鼠,褪黑素处理使肿瘤体积明显下降、肿瘤组织出现自噬形态和beclin-1、LC3-Ⅱ水平显著上调;在MFC细胞,褪黑素使细胞增殖率明显下降、形成自噬泡和beclin-1、LC3-Ⅱ水平明显上调,MLT+3-MA联合给药使MFC细胞增值率下降更加显著。结论褪黑素体内外抑制胃癌细胞增殖过程中,肿瘤细胞通过增强自噬而产生自我保护作用;自噬抑制剂3-MA通过抑制细胞自噬可增强褪黑素的肿瘤抑制作用。

Objective To investigate the role of autophagy in inhibition of gastric cancer cell proliferation by melatonin(MLT)in vitro and in vivo.Methods Twenty-four mice bearing gastric cancer were randomly divided into control group and intervention groups treated with different doses of melatonin.After 1 week of administration,the tumor tissues were taken for volume measurement,electron microscopic observation,expression detection of autophagy-associated protein beclin-1,LC3-Ⅱ.In addition,murine forega-stric carcinoma(MFC)cells were cultured and divided into control group,MLT group,3-methyl adenine(3-MA)group and MLT+3-MA combined drug administration group.Cells proliferation rate after 24 hours of drug intervention was detected by CCK-8 method,and cells were aslo observed by electron microscopy,beclin-1,LC3-Ⅱexpression were detected.Results In vivo experiments of tu-mor-bearing mice the tumor volume of both two doses of melatonin treatment group decreased significantly.The tumor tissue showed autophagy morphology and the expressions of beclin-1 and LC3-Ⅱwere signi ficantly up-regulated.In vitro experiments of MFC cells,the proliferation rate of MFC cells in the melatonin treatment group decreased significantly,while formation of autophagic vacuoles and the expression of beclin-1 and LC3-Ⅱproteins were up-regulated.The proliferation rate of cells in the MLT+3-MA combination group decreased more significantly.Conclusion In the process of the proliferation inhibition of gastric cancer cells by melatonin in vitro and in vivo,tumor cells self-protected themselves by enhancement of the autophagy.Autophagy inhibitor 3-MA can enhance the anti-tumor effect of melatonin by inhibiting autophagy.