Abstract: ObjectiveTo investigate the effect of miR27a mimic and inhibitor on proliferation and apoptosis in melanoma cell line WM239. MethodsThe miR27a mimic, inhibitor and its negative control were transfected into WM239 cells. The transfection efficiency was evaluated by fluorescence microscope. The expression of miR27a was detected by realtime fluorescent quantitative PCR. The proliferation of cells was detected by MTT. The cell apoptosis and cell cycle were analyzed by flow cytometry. ResultsThe transfection efficiency in WM239 cells was 80% to 90%. The expression of miR27a was markedly upregulated in miR27a mimic group（2△△CT value is 26.98±0.01), with statistically significant difference(t＝-1 123.67, P=0.00）; and the miR27a inhibitor group showed lower expression of miR27a（2△△CT value is 0.96±0.02),  there was no statistically significant difference compared with normal control group(t＝0.04, P＝0.06）. The proliferation of cells was obviously inhibited in miR27a mimic group, and there was statistically significant difference compared with normal control group ［absorbance of 72 h（0.45±0.02）∶（0.72±0.01），F＝129.56, P＜0.05］. The percentage of WM239 cells in G0G1 phase was increased［（74.83±1.46）∶（63.73±1.25），F＝30.33, P＜0.05］, and the percentage of WM239 cells in S phase and G2M phase were decreased ［（21.33±1.75）∶（27.50±1.25），F＝14.98，P＜0.05；（3.90±1.31）∶（8.80±2.10），F＝3.66，P＜0.05］. The apoptosis rate of cells was significantly increased in miR27a mimic group compared with normal group ［（29.67±0.91）%∶（1.44±0.85）%，F＝530.90，P＜0.01］, but the inhibitor group had no obvious effect on cell cycle and cell apoptosis. ConclusionMiR27a can suppress melanoma cell proliferation and act as a tumor suppressor gene, which is relevant to induce cell apoptosis and block cell cycle in G0G1 phase.

Key words: Melanoma, Cell proliferation, Apoptosis, Transfection, microRNA27a