CIAPIN1 targets Na+/H+ exchanger 1 to mediate K562 chronic myeloid leukemia cells' differentiation via ERK1/2 signaling pathway

CIAPIN1 (cytokine-induced antiapoptotic inhibitor 1) was recently identified as an essential downstream effector of the Ras signaling pathway. However, its potential role in regulating myeloid differentiation remains unclear. In this study, we found depletion of CIAPIN1 by shRNAs led to granulocytic differentiation of K562 cells. Meanwhile, the decrease of NHE1 and up-regulation of phosphorylated ERK1/2 were observed after CIAPIN1 depletion. Interestingly, targeted inhibition of NHE1 further promoted the differentiation of K562 cells with CIAPIN1 silencing. Accordingly, ectopic expression of NHE1 reversed this phenotype. Furthermore, ERK1/2 inhibition with the chemical inhibitor, PD98059, abolished CIAPIN1 silencing-induced differentiation of K562 cells after NHE1 inhibition. Thus, our results revealed important mechanism that CIAPIN1 targeted NHE1 to mediate differentiation of K562 cells via ERK1/2 pathway. Our findings implied CIAPIN1 and NHE1 could be new targets in developing therapeutic strategies against leukemia. (C) 2014 Elsevier Ltd. All rights reserved.