[Effect of microRNA143 expression on cell proliferation in colonic carcinoma].

ABSTRACT

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. 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.