Fig. 5
miR-509-3p regulates cell proliferation, invasion, and chemoresistance through SUMO-3. A Left panel: the putative miR-509-3p binding site in its 3′-UTR contains mutant wt-SUMO-3 and the corresponding mut-SUMO-3 (red star). Right panel: A2780CP70 cells were co-transfected with the wt-SUMO-3/mut-SUMO-3 vector and miR-509-3p NC/miR-509-3p mimics. Compared with that of the control group, the luciferase activity of the wt-SUMO-3 reporter gene was significantly reduced by miR-509-3p mimic transfection. In cells co-transfected with the miR-509-3p and mut-SUMO-3 reporter genes, the reporter gene activity did not significantly decrease. B The protein expression of SUMO-3 in A2780CP70 and OVCAR-8 cells transfected with miR-509-3p mimics, as well as that in A2780 and OVCAR-3 cells transfected with the miR-509-3p inhibitor, were evaluated using western blotting. β-actin was using as a loading control. C Upper panel: the protein expression of COL11A1 and SUMO-3 in A2780/COL11A1 cells transfected with miR-509-3p mimics, as well as that of A2780CP70/shCOL11A1 cells transfected with the miR-509-3p inhibitor, were evaluated using western blotting. β-actin was used as a loading control. Lower panel: the mRNA expression levels of miR-509-3p in A2780/COL11A1 cells transfected with miR-509-3p mimics, as well as those of A2780CP70/shCOL11A1 cells transfected with the miR-509-3p inhibitor were evaluated using real-time RT-PCR. All experiments were performed in triplicate. D A2780CP70 cells were co-transfected with pCMV3-ORF-SUMO-3 and miR-509-3p/NC. The MTT results showed that the cell proliferation rate was obviously decreased after transfection with the miR-509-3p mimics, while the overexpression of SUMO-3 reversed the apparent cell proliferation inhibition induced by miR-509-3p. NC: negative control; *** P < 0.001. E A2780CP70 cells were co-transfected with pCMV3-ORF-SUMO-3 and miR-509-3p/NC, and then their invasive ability was evaluated. All data represent the mean ± SD of three separate experiments; * P < 0.05, ** P < 0.01, compared with the control. F A2780CP70 cells were co-transfected with pCMV3-ORF-SUMO-3 and miR-509-3p/NC, and then treated with different concentrations of cisplatin for 48 h. Cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. All experiments were performed in triplicate. G A model illustrating the hypothetical role of miR-509-3p regulation in ovarian cancer cells