The role of miR-15a/16-1 in the regulation of leukemic cell proliferation. (A) and (B) K562 and HL-60 cells were incubated with 1.5 ug siRNA-WT1, 1.5 ug N.C or neither of the above for 24 and 48 hours, then the relative expression of WT1 and the corresponding WT1 protein level were separately measured by quantitative real-time PCR and Western blotting. (C) and (D) K562 and HL-60 cells treated with siRNA or N.C or neither of the above were measured by CCK-8 assay at different time periods. Data are shown as mean ± SD from three independent experiments. *P < 0.05 versus negative control.