In vitro and in vivo requirement of HNRPK for BCR/ABL oncogenic potential. (Ai) HNRPK levels in parental 32Dcl3, 32D-BCR/ABL, and 32D-BCR/ABL cells transduced with an antisense (lane 3) or an shRNA (lane 5) HNRPK retroviral construct. (Aii) Effect of HNRPK down-regulation by shRNA (lane 3) on the levels of the HNRPK- and BCR/ABL-regulated Myc protein. (B) Effect of HNRPK down-regulation on the growth factor-independent proliferation of 32D-BCR/ABL cells. (C) Effect of Hnrpk antisense and shRNA on the growth factor-independent clonogenic efficiency of 32D-BCR/ABL cells. Bars represent mean ± SE of data from 3 independent experiments. (D) 32D-BCR/ABL and GFP⁺ 32D-BCR/ABL cells retrovirally transduced with pSuper-retroneo-Hnrpk shRNA were induced to differentiate with G-CSF. Cells were subjected to cytospin and were May-Grünwald/Giemsa stained. 32Dcl3 parental cells were used as a control for granulocyte colony-stimulating factor (G-CSF)-induced granulocytic differentiation. Images were taken with a Zeiss Axioskope 2 Plus and a 40×/0.75 NA objective, with a Canon Powershot A70 (Canon, Lake Success, NY) and Canon Capture software.