Nerve growth factor potentiated the sodium butyrate- and PMA-induced megakaryocytic differentiation of K562 leukemia cells

We have recently reported that retinoic acid (RA) induced the expression of trkA, the high affinity receptor for nerve growth factor (NGF), in human c hronic myelogenous leukemia K562 cells. In this paper, we examined the abil ity of several other differentiation inducers to regulate the expression of trkA and NGF in K562 cells. We found that the expression of trkA was drama tically induced by the two megakaryocyte lineage inducers sodium butyrate ( NaBut) and phorbol 12-myristate 13-acetate (PMA), but not by the two erythr ocyte lineage inducers hemin or 1-beta-D-arabinofuranosyl cytosine (Ara-C). Furthermore, activation of the up-regulated trkA receptor by exogenous NGF potentiated the megakaryocytic differentiation of K562 cells induced by Na But and PMA. Our results demonstrated that trkA is one of the essential gen es that are up-regulated and involved in the megakaryocytic differentiation of K562 leukemia cells triggered by these differentiation inducers. Our fi ndings suggest that NGF, in addition to its pivotal roles in the nervous sy stem, may also play important roles in hematopoietic differentiation. (C) 2 000 Elsevier Science Ltd. All rights reserved.