MiR-18b-5p对大肠癌PTEN/PI3K/Akt2信号通路的调控

目的:探讨miR-18b-5p对大肠癌PTEN/PI3K/Akt2信号转导通路的调控。方法:qRT-PCR方法检测33例大肠癌患者癌组织中miR-18b-5p表达水平，将患者临床病理特征与癌组织miR-18b-5p表达水平进行独立样本t检验和多元线性回归分析。应用microrna.org预测miR-18b-5p靶基因，miR-18b-5p 类似物、抑制物转染肠癌细胞SW480及HCT116，qRT-PCR检测细胞PTEN、PI3K、Akt2 mRNA表达水平。结果:在大肠癌患者癌组织中，miR-18b-5p表达水平显著增高，为癌旁组织的3.6倍(P<0.01 )，其表达水平与肿瘤分化程度、淋巴结转移及TNM分期相关。Microrna.org预测PTEN可能是miR-18b-5p的靶基因，大肠癌细胞转染类似物后PTEN含量明显降低，其下游基因PI3K、Akt2表达增高。结论:miR-18b-5p下调抑癌基因PTEN表达，诱导PI3K/Akt2信号转导通路持续活化，促进了大肠癌的发生发展。

Role of microRNA-18 b-5 p targeting PTEN/PI3 K/Akt2 in colorectal cancer

Objective:To investigate the expression of miR-18b-5p in cancerous tissues of patients with colorectal cancer (CRC) and its role on PTEN/PI3K/Akt2 signal pathway in colorectal cancer cell.Methods:The expression of miR-18b-5p was detected by using qRT-PCR in cancer tissues and para-cancerous controls.Microrna.org predicted that the PTEN was a target of miR-18b-5p.The mRNA expressions of PTEN，PI3K，Akt2 were examined by qRT-PCR，respectively.Results:MiR-18b-5p was significantly increased in cancerous tissues from CRC patients compared with the para-cancerous control.The expression of miR-18b-5p in CRC was related to tumor differentiation grade, metastatic lymph node and TNM stage.In vitro，the expression of miR-18b-5p in colorectal cancer cell was significantly up-regulated after transfected with miR-18b-5p mimic，while PTEN expression was significantly reduced.There was a negative correlation between miR-18b-5p and PTEN expression in cancer tissue.Furthermore，PI3K/Akt2 was apparently up-regulated as well.Conclusion:MiR-18b-5p can activate the PI3K/Akt2 signal pathway through inhibition of PTEN and promote occurrence and development of CRC.