miR-302a对结直肠癌细胞奥沙利铂化疗敏感性的影响及机制

目的:探究miR-302a对结直肠癌细胞奥沙利铂化疗敏感性的影响及机制。方法:在四株结直肠癌细胞系HT29、HCT8、SW480、SW1463中，通过转染miR-302a mimic构建miR-302a过表达模型，RT-PCR检测过表达效果；CCK-8法检测转染48 h后高表达miR-302a细胞的增殖能力及对奥沙利铂的敏感性；蛋白质印迹法检测转染后P-gp蛋白及Wnt/β-catenin通路相关蛋白MMP-7、c-Jun、c-myc、β-catenin、LEF1的变化。结果:相比正常小肠上皮细胞HIEC，miR-302a在结直肠癌细胞系HT29、HCT8、SW480、SW1463中的表达较低。转染mimic后，miR-302a的表达明显上调（P<0.001）。增殖实验发现miR-302a的上调并不影响结直肠癌细胞的增殖，而在转染miR-302a的细胞中加入奥沙利铂，miR-302a组HT29、HCT8、SW480和SW1463细胞存活率相比miR-NC组分别降低2.46、1.89、2.39、2.86倍。进一步探究miR-302a增加奥沙利铂敏感性的机制，发现miR-302a可抑制P-gp蛋白的表达，并且抑制Wnt/β-catenin通路相关蛋白MMP-7、c-Jun、c-myc、β-catenin、LEF1的表达。结论:miR-302a可增加结直肠癌细胞奥沙利铂化疗敏感性，其机制可能是通过抑制P-gp的蛋白表达，并抑制Wnt/β-catenin信号通路相关蛋白表达而实现。

Role of miR-302a in oxaliplatin-resistance of colorectal cancer

Objective:To investigate the role of miR-302a in oxaliplatin-resistance of colorectal cancer(CRC)and primarily search the mechanism.Methods:HT29，HCT8，SW480，SW1463 cells were transfected with mimic to increase miR-302a expression，and RT-PCR identified transfection efficiency.CCK-8 detected CRC cells proliferation and sensitivity to oxaliplatin therapy.Western blot detected protein level of P-gp and Wnt/β-catenin pathway related protein.Results:Compared with human normal epithetial cells HIEC，CRC cells HT29，HCT8，SW480，SW1463 had a lower level of miR-302a.Expression of miR-302a could be increased siginificantly after transfecting miR-302a mimic(P<0.001).miR-302a could not influence CRC cells proliferation by CCK-8 assay，and miR-302a increased oxaliplatin-sensitivity in HT29，HCT8，SW480 and SW1463 cells.After treating HT29，HCT8，SW480 and SW1463 cells with oxaliplatin，survival rate of miR-302a group was 2.46，1.89，2.39，2.86 fold lower than that in miR-NC group.We further found miR-302a could suppress protein expression of P-gp and Wnt/β-catenin pathway related protein(MMP-7，c-Jun，c-myc，active β-catenin，LEF1).Conclusion:miR-302a increased oxaliplatin-sensitivity of CRC，and the possible mechanism was that miR-302a could suppress P-gp and Wnt/β-catenin pathway related protein expression.