MiR-21靶向调控PTEN对胃癌细胞增殖、凋亡和侵袭的影响

Effect of MiR-21 on Proliferation,Apoptosis and Invasion of Gastric Cancer Cells by Targeting PTEN

背景:胃癌是一种常见的消化道恶性肿瘤,miR-21可调节磷酸酶及张力蛋白同源物(PTEN)蛋白表达,诱导多种肿瘤细胞凋亡。目的:探讨miR-21靶向调控PTEN对胃癌细胞增殖、凋亡和侵袭的影响。方法:将对数生长期SGC-7901细胞分为miR-21 mimic组、miR-21 inhibitor组、阴性对照组和空白对照组,采用RT-PCR和蛋白质印迹法分别检测miR-21和PTEN mRNA和蛋白表达,萤光素酶报告基因试验验证两者的靶向关系。将胃癌SGC-7901细胞分为空白对照组、NC组、miR-21组、PTEN组和miR-21+PTEN组,以CCK-8法检测细胞增殖活性,TUNEL法检测细胞凋亡情况,Transwell法检测细胞侵袭力,划痕实验检测细胞迁移力,蛋白质印迹法检测Ki-67、PCNA、cleaved caspase-3、Bcl-2、Bax、PTEN、p-PI3K/PI3K和p-Akt/Akt蛋白表达。建立裸鼠成瘤模型,检测过表达miR-21对移植瘤体积和质量的影响。结果:MiR-21可靶向负调控PTEN表达。与NC组相比,miR-21组细胞增殖、侵袭和迁移率升高(P<0.05),细胞凋亡率下降(P<0.05),Ki-67、PCNA、Bcl-2/Bax比例、p-PI3K/PI3K和p-Akt/Akt蛋白表达升高(P<0.05),PTEN、cleaved caspase-3表达下降(P<0.05);PTEN组细胞增殖、侵袭和迁移率下降(P<0.05),细胞凋亡率升高(P<0.05),Ki-67、PCNA、Bcl-2/Bax比例、p-PI3K/PI3K和p-Akt/Akt蛋白表达下降(P<0.05),PTEN和cleaved caspase-3表达升高(P<0.05)。与PTEN组相比,miR-21+PTEN组细胞增殖、侵袭和迁移率升高(P<0.05),细胞凋亡率下降(P<0.05),Ki-67、PCNA、Bcl-2/Bax比例、p-PI3K/PI3K和p-Akt/Akt蛋白表达升高(P<0.05),PTEN、cleaved caspase-3表达下降(P<0.05)。与对照组相比,过表达miR-21可增加裸鼠移植瘤的体积和质量(P<0.05)。结论:MiR-21可靶向负调控PTEN表达,激活PI3K/Akt信号通路,促进胃癌细胞增殖、侵袭和迁移,并抑制细胞凋亡。

Background:Gastric cancer is a common gastrointestinal malignant tumor.MiR-21 can regulate the expression of phosphatase and tensin homologue(PTEN)protein and induce apoptosis of various tumor cells.Aims:To explore effect of miR-21 on proliferation,apoptosis and invasion of gastric cancer cells by targeting PTEN.Methods:SGC-7901 cells in logarithmic growth phase were divided into miR-21 mimic group,miR-21 inhibitor group,negative control group and blank control group.RT-PCR and Western blotting were used to detect mRNA and protein expressions of miR-21 and PTEN,respectively.The luciferase reporter gene assay was used to validate the targeted regulatory relationship between miR-21 and PTEN.Gastric cancer SGC-7901 cells were divided into blank control group,NC group,miR-21 group,PTEN group and miR-21+PTEN group.The proliferation activity was determined by CCK-8 assay,apoptosis was detected by TUNEL assay,and invasion and migration ability of cells was detected by Transwell and scratch test,respectively.The expressions of Ki-67,PCNA,ratio of cleaved caspase-3,Bcl-2,Bax,PTEN,p-PI3K/PI3K and p-Akt/Akt proteins were detected by Western blotting.A tumorigenesis model of nude mice was established to detect the effect of overexpression of miR-21 on the volume and mass of transplanted tumor.Results:MiR-21 could negatively regulate expression of PTEN.Compared with NC group,cell proliferation,invasion and migration rates were significantly increased in miR-21 group(P<0.05),apoptosis rate was significantly decreased(P<0.05),expressions of Ki-67,PCNA,ratio of Bcl-2/Bax,p-PI3K/PI3K and p-Akt/Akt proteins were significantly increased(P<0.05),expressions of PTEN and cleaved caspase-3 was significantly decreased(P<0.05).Cell proliferation,invasion and migration rates were significantly decreased in PTEN group(P<0.05),apoptosis rate was significantly increased(P<0.05),expressions of Ki-67,PCNA,ratio of Bcl-2/Bax,p-PI3K/PI3K and p-Akt/Akt proteins were significantly decreased(P<0.05),expressions of PTEN and cleaved caspase-3 were significantly increased(P<0.05).Compared with PTEN group,cell proliferation,invasion and migration rates were significantly increased in miR-21+PTEN group(P<0.05),apoptosis rate was significantly decreased(P<0.05),expressions of Ki-67,PCNA,ratio of Bcl-2/Bax,p-PI3K/PI3K and p-Akt/Akt proteins were significantly increased(P<0.05),and expressions of PTEN and cleaved caspase-3 were significantly decreased(P<0.05).Compared with the control group,overexpression of miR-21 significantly increased the volume and mass of transplanted tumor in nude mice(P<0.05).Conclusions:MiR-21 can negatively regulate PTEN expression,activate PI3K/Akt signaling pathway,promote proliferation,invasion and migration of gastric cancer cells,and inhibit cell apoptosis.