Down-regulation of miR-141 in gastric cancer and its involvement in cell growth

Human microRNA-141 (miR-141), a member of the miR-200 family, has been reported to be associated with various human malignancies. However, it remains unknown whether miR-141 is involved in the pathogenesis of gastric cancer. Therefore, we examined the expression of miR-141 in gastric cancer tissues and the effect of miR-141 overexpression on cancer cell proliferation. The expression level of miR-141 in 35 pair-matched gastric neoplastic and adjacent non-neoplastic tissues, and in 5 gastric cancer cell lines were examined by quantitative real-time PCR. The growth of MGC-803 cells transfected with miRNA precursor was examined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazoliumbromide) assay. MiR-141 was significantly down-regulated in 80% (28/35) of primary gastric cancer tissues compared with pair-matched adjacent non-tumor tissues (P < 0.01). The expression of miR-141 was also found to be substantially reduced in several human gastric cancer cell lines such as MGC-803, HGC-27, SGC-7901 and BGC-823 cells. Overexpression of miR-141 with its precursors significantly inhibited the proliferation of gastric cancer cells. These results suggest that miR-141 may be involved in the development of gastric cancer through its inhibitory effect on cell proliferation.