Withdrawal of miR-125b expression leads to decreased cell number and increased apoptosis. (A) Primary AF9+Ri125b+Dox AML cells were cultured in vitro in the presence or absence of Dox. Relative miR-125b expression levels were determined at the indicated days. U6 was used as a control (n = 3; *P < .01). (B) Viable cell counts for +Dox and −Dox cells at indicated days, for experiment described in (A) (n = 3; *P < .05; **P < .001). (C) Cells in experiment described in (A) were harvested on day 3 and stained with annexin V and 7-aminoactinomycin D (7-AAD). Representative flow cytometry plots (of 3 replicates) are shown. (D) Quantification of annexin V⁺ 7-AAD− cells for the experiment described in (C) (n = 3; error bars represent standard deviation; **P < .01).