miR-374a negatively regulates FOXO1 to promote the proliferation and induce the apoptosis of ovarian cancer cells. (A) A potential binding site of miR-374a in FOXO1 was predicted. (B) A2780 cells were co-transfected with miR-374a mimics or mimics NC and luciferase reporter plasmids carrying WT or MUT FOXO1 3′UTR, and luciferase activity was measured. (C and D) A2780 cells were transfected with mimics NC, miR-374a mimics, inhibitor NC or miR-374a inhibitor and the relative (C) gene and (D) protein expression levels of FOXO1 were analyzed using RT-qPCR and western blotting, respectively. (E) A2780 cells were transfected with empty pcDNA3.1 plasmid or FOXO1 plasmid, and the relative gene and protein expression levels of FOXO1 were analyzed using RT-qPCR and western blotting, respectively. (F and G) A2780 cells were transfected with mimics NC, miR-374a mimics, miR-374a mimics and pcDNA3.1, or miR-374a mimics and FOXO1. (F) Cell proliferation was analyzed using a Cell Counting kit-8 assay. (G) Apoptosis was detected using flow cytometry. Data are presented as the mean ± SD, n=3. *P<0.05 and **P<0.01. FOXO1, forkhead box O1; miR, microRNA; MUT, mutant; NC, negative control; RT-qPCR, reverse transcription-quantitative PCR; WT, wild-type.