Abstract: Objective  To evaluate the effect of microRNA-182-5p (miR-182-5p) on proliferation and apoptosis of non-small cell lung cancer (NSCLC) A549 cells by targeting forkhead box O3a (FOXO3a). Methods  The difference of miR-182-5p expression between human normal lung epithelial cells BEAS-2B and NSCLC cells A549 was compared. The A549 cells were chosen, and miR-182-5p mimic (miR-182-5p mimic group), miR-182-5p inhibitor (miR-182-5p inhibitor group), negative control mimic (NC mimic group) and negative control inhibitor (NC inhibitor group) were transfected respectively. The expression of miR-182-5p was detected by reverse transcriptionpolymerase chain reaction (RT-PCR). The protein expression of FOXO3a was detected by Western blotting. The cell proliferation activity was detected by methyl thiazolyl tetrazolium (MTT) method. The cell apoptosis was detected by flow cytometry. The targeted relationship between miR-182-5p and FOXO3a was detected by dualluciferase experiment. Results  The miR-182-5p expression of A549 cells and BEAS-2B cells respectively was 3.21±0.24 and 1.01±0.11, and the difference was statistically significant (t=14.209, P＜0.001). The miR182-5p expression of NC mimic group, miR-182-5p mimic group, NC inhibitor group and miR-182-5p inhibitor group respectively was 1.09±0.20, 12.80±1.10, 1.03±0.11 and 0.47±0.08, and the difference was statistically significant (F=87.872, P＜0.001). The FOXO3a expression of the above four groups respectively was 118.34±16.71, 50.89±11.58, 125.33±20.87 and 289.26±34.51, and the difference was statistically significant (F=62.125, P＜0.001). The 72 h proliferation activity of the four groups respectively was 1.12±0.13, 1.70±0.14, 1.07±0.13 and 0.71±0.11, and the difference was statistically significant (F=31.336, P＜0.001). The proliferation activity of miR-182-5p mimic group was significantly higher than that of NC mimic group (P＜0.05), and the proliferation activity of miR-182-5p inhibitor group was significantly lower than that of NC inhibitor group (P＜0.05). The apoptosis rate of the four groups respectively was (5.51±1.80)%, (1.41±0.50)%, (6.24±1.71)% and (47.93±5.12)%, and the difference was statistically significant (F=211.081, P＜0.001). The apoptosis rate of miR1825p mimic group was significantly lower than that of NC mimic group (P＜0.05), and the apoptosis rate of miR-182-5p inhibitor group was significantly higher than that of NC inhibitor group (P＜0.001). The miRNA target genes prediction software test results showed that miR-182-5p could act on FOXO3a 3′-untranslated region (UTR). Compared with transfection NC mimic, co-transfection miR-182-5p mimic and FOXO3aWt could make luciferase activity of A549 significantly decreased (1.20±0.14 vs. 0.62±0.10; t=5.839, P=0.004）. Conclusion  miR-182-5p can enhance proliferation and inhibit apoptosis of A549 cell by targeting FOXO3a.

Key words: Carcinoma, non-small-cell lung, MicroRNA-182-5p, Forkhead box O3a