Induction of gp130 and LIF by differentiation inducers in human myeloid leukemia K562 cells

It has been previously shown that phorbol 12-myristate 13-acetate (PMA), a potent differentiation inducer, induced the expression of both interleukin- 6 (IL-6) and IL-6 receptor alpha component (IL-6R alpha) in K562 leukemia c ells. In the present study, we examined the ability of several differentiat ion inducers to regulate the expression of the signal-transducing receptor component for IL-6, gp 130, and cytokine leukemia inhibitory factor (LIF) i n K562 cells, We found that the expression of gp130 was dramatically induce d at both the mRNA and protein levels by the two megakaryocytic inducers so dium butyrate (NaBut) and PMA. In contrast, the mRNA expression of LIF was induced by the two erythroid inducers l-beta-D-arabinofuranosyl cytosine (A ra-C) and hemin. Furthermore, activation of the PMA-induced gp130 receptor by exogenous IL-6 potentiated the differentiating effects of PMA. Our findi ngs suggest that IL-6/gp130 signaling may be involved in the regulation of the megakaryocytic differentiation of K562 cells. (C) 1999 Elsevier Science Ltd. All rights reserved.