INDUCTION OF TRKA RECEPTOR BY RETINOIC ACID IN LEUKEMIA-CELL LINES

To explore the potential involvement of neurotrophins in the actions o f retinoic acid (RA) on leukaemia differentiation, we examined the abi lity of RA to regulate the expression of neurotrophins and Trk recepto rs in several leukaemia cell lines. Expression of TrkA was dramaticall y induced by RA at both the mRNA and protein level in leukaemia cell l ines K562 and KG-1. Furthermore, while no expression of trkB and trkC was detected, constitutive expression of nerve growth factor (NGF), ne urotrophin-3 and neurotrophin-4/5 could be detected in leukemia cells. Our findings suggested that NGF/trkA may potentially be involved in t he RA-induced differentiation of leukemia cells.