microRNA143表达对结肠癌组织中细胞增殖的影响及其作用机制

目的 探讨microRNA143(miR-143)表达对结肠肿瘤组织中细胞增殖和K-ras基因表达的影响.方法 采用Northern blot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Western blot方法检测K-rasmRNA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-ras mRNA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-ras蛋白的表达.

Effect of microRNA143 expression on cell proliferation in coiorectal carcinoma

Objective To investigate the effect of mieroRNA143 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. A 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.