Enforced expression of miR-125b affects STAT3 signaling at multiple levels. (A) Western blotting of phospho-STAT3 (p-STAT3) and STAT3 in 32D/miR-ctrl and 32D/miR-125b cells in continuously growing culture (IL-3) and after indicated time points of G-CSF stimulation. (B) Expression level of Socs3 mRNA in 32D/miR-ctrl (left graph) and 32D/miR-125b (right graph) cells at indicated time points of G-CSF treatment. Hprt served as an endogenous control. (C) Western blotting of p-STAT3 and STAT3 in cytosolic (left panel) and nuclear (right panel) fractions of 32D/miR-ctrl and 32D/miR-125b cells. Both membranes were exposed at the same time. (D) Analysis of DNA-binding of STAT3 in 32D/miR-ctrl and 32D/miR-125b cells after indicated time points of G-CSF stimulation. Seven μg of nuclear fraction was used. OD/G-CSF values normalized to OD/IL-3 are presented. Mean of 4 (panels B,D) and representative experiments are shown, respectively. *P < .05 compared with corresponding control at indicated time points.