Effects of miR-15a/16-1 on the proliferation of K562 and HL-60 cells. K562 and HL-60 cells were transfected with pRS-15/16 or pRS-E vector (negative control) for 24, 48 and 72 hours, then the relative expressions of miR-15a/16-1 were measured by qRT-PCR (A and B). CCK-8 assay (C and E) and direct cell count (D and F) were performed when K562 and HL-60 cells were transfected with pRS-15/16 or pRS-E vector at different time periods. Data are shown as mean ± SD from three independent experiments. *P < 0.05 versus negative control.