microRNA143表达对结肠癌组织中细胞增殖的影响及其作用机制

Effect of microRNA143 expression on cell proliferation in colorectal carcinoma

目的探讨microRNA143（miR-143）表达对结肠肿瘤组织中细胞增殖和K-ra8基因表达的影响。方法采用Northernblot方法检测21例结肠癌组织和癌旁组织中miR-143的表达；构建miR-143的表达载体，将其转入人结肠癌细胞系SW480，用二苯基溴化四氮唑蓝（MTT）方法检测miR-143转染对细胞增殖的影响；通过逆转录聚合酶链反应（RT-PCR）和Westernblot方法检测K-ras mRNA和蛋白的表达变化。结果在21例结肠癌组织标本中，有17例（81．0％）癌组织的miR-143表达水平低于癌旁组织。基因转染的SW480细胞中，miR-143表达水平显著升高，细胞增殖被抑制，K-ras蛋白的表达水平下降约40．3％，而K-ra8mRNA水平未受影响。结论miR-143在结肠癌组织中的表达明显低于癌旁组织，转染细胞中高表达的miR-143能够抑制细胞增殖，下调K-ra8蛋白的表达。

Objective To investigate the effect of microRNA143 on cell proliferation and K-ras expression in colorectal carcinoma. Methods Northern blot was used to examine the expression of miR-143 in colorectal carcinoma and adjacent normal tissues, h miR-143 expression vector was constructed and transfected into a human colon adenocarcinoma cell line SW480. Cell proliferation was evaluated by MTT assay. RT-PCR and Western blot were used to examine the expression of K-ras oncogene in transfected cells. Results The level of mature miR-143 was lower in tumors compared with adjacent normal tissues in 81% of colorectal carcinoma specimens. In transfected cells, the increased accumulation of miR-143 inhibited the cell proliferation, and resulted in approximately 40. 3% decrease of K-ras protein levels, but had no effect on level of K-ras mRNA. Conclusion The increased accumulation of miR-143 inhibits the proliferation of transfected cells, and results in down-regulation of K-ras protein in colorectal carcinoma.