C/EBPα-p42 up-regulates miR-223 and leads to down-regulation of E2F1 protein expression. (A-B) K562-C/EBPα-p42-ER cells and K562-ER cells (A) and K562-C/EBPα-p30-ER cells and K562-C/EBPα-BRM2-ER cells (B) were induced with β-estradiol (5μM) for respective time points. Total RNA was analyzed by quantitative real-time RT-PCR with oligos for miR-223. Data are represented as mean ± SD from 3 independent experiments. *P < .05; **P < .01. (C) K562-C/EBPα-p42-ER cells and K562-ER cells were induced with β-estradiol (5μM) for respective time points. Total protein was analyzed by Western blot analysis with anti-E2F1 antibody. Values below the gel image indicate the down-regulation (fold) of E2F1 protein level normalized to β-tubulin.