SPHINGANINE POTENTIATION OF DIMETHYL SULFOXIDE-INDUCED GRANULOCYTIC DIFFERENTIATION, INCREASE OF ALKALINE-PHOSPHATASE ACTIVITY AND DECREASEOF PROTEIN-KINASE-C ACTIVITY IN A HUMAN LEUKEMIA-CELL LINE (HL-60)

The differentiation of HL-60 promyelocytic cells toward mature granulo cytic cells induced by dimethyl sulfoxide (DMSO) was accompanied by a quantitative similar increase in alkaline phosphatase (ALP) activity a nd decrease in protein kinase C (PKC) activity. The combination of DMS O and sphinganine (SP), a potent inhibitor of PKC, increased in parall el the percentage of mature cells and the ALP activity. The enhancemen t of DMSO-induced differentiation and the potentiation of the decrease of PKC activity by SP also seemed to correlate with each other. Our r esults indicate that both ALP and PKC may play a role in the DMSO-indu ced granulocytic differentiation. (C) 1994 Academic Press, Inc.