目的:探讨在喉癌细胞株Hep－2中上调miRNA let－7a的表达对高迁移率族蛋白(high mobility group A,HMGA2)的作用机制以及对喉癌细胞增殖的影响.方法:合成miRNA let－7a模拟体(let－7a mim-ics)并采用阳离子脂质体法转染入Hep－2内;分别用流式细胞术和MTT法检测let－7a高表达对细胞凋亡和增殖的影响;实时荧光PCR(Real－time qPCR)和Western blot检测上调let－7a后对HMGA2表达的影响.结果:本实验将let－7a mimics成功转染入Hep－2内,流式细胞术及MTT法检测显示Hep－2内let－7a的表达上调会抑制喉癌细胞的增殖,促进喉癌细胞的凋亡.RT－qPCR检测显示:let－7a mRNA在空白组和阴性对照组(NC组)的表达水平明显低于实验组(P＜0.05);HMGA2 mRNA在空白组、NC组的表达水平明显高于实验组(P＜0.01).Western blot检测细胞中HMGA2蛋白的表达显示:实验组HMGA2蛋白的表达量明显低于空白组和NC组(P＜0.01).上述实验中空白组与NC组之间比较均无统计学差异(P＞0.05).结论:let－7a能够显著下调HMGA2基因和蛋白的表达,抑制喉癌细胞的增殖,促进其凋亡,为喉癌基因靶向治疗提供坚实的理论基础.%Objective:To investigate the mechanism of the up regulation of the expression of miRNA let－7a on HMGA2 in laryngeal carcinoma cell line Hep－2 and its effect on the laryngeal carcinoma cells.Methods:Let－7a mimics was synthesized and transfected into Hep－2 by cationic liposome.Flow cytometry and MTT assay was used to detect the effect of up regulation of let－7a on apoptosis and cell proliferation respectively.The effection on HMGA2 was detected by Real－time qPCR and Western blot after up regulation of let－7a expression.Results:Let－7a mim-ics was successfully transfected into Hep－2.It was showed that the expression of let－7a inhibited proliferation and promoted apoptosis of laryngeal carcinoma cells.The expression levels of let－7a in the blank and NC group were sig-nificantly lower than that in the experimental group(P＜0.05).The expression levels of HMGA2 in the blank and NC group were significantly higher than that in the experimental group(P＜0.01).The expression of HMGA2 protein in the experimental group was significantly lower than those in the blank and NC group(P＜0.01).There was both no statistical significance between the blank and NC group in RT－qPCR and Western blot(P＞0.05).Conclusion:Let－7a inhibits expression of HMGA2 in a targeted manner,and inhibits proliferation and promotes apoptosis of larynge-al carcinoma cells,which provide a solid theoretical basis for targeted therapy of laryngeal carcinoma.
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