Effects of miR-505 on cell proliferation in the MCF-7 and MDA-MB-232 cell lines. The expression of miR-505 in (A) MCF-7 and (B) MDA-MB-232 cells was significantly higher following transfection with miR-505 mimic and significantly lower following transfection with miR-505 inhibitor compared with untreated cells ***P<0.001. Proliferation of (C) MCF-7 and (D) MDA-MB-231 cells was significantly inhibited following transfection with miR-505 mimic and significantly enhanced following overexpression of miR-505. All experiments were repeated three times. *P<0.05, **P<0.01, ***P<0.001 vs. untreated. miR-505, microRNA-505; NC, negative control; OD, optical density.