ALKALINE-PHOSPHATASE ACTIVITY IN THE HUMAN PROMYELOCYTIC LEUKEMIA-CELL LINE, HL-60, INDUCED BY RETINOIC ACID AND RECOMBINANT HUMAN GRANULOCYTE-COLONY-STIMULATING FACTOR

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) not only enhanced the growth of HL-60 cells, but also significantly increa sed NBT-reducing ability and alkaline phosphatase (ALP) activity of th e cells, which were enhanced by the treatment with retinoic acid (RA). Protein kinase C inhibitors (H-7 and staurosporine) significantly sup pressed this induction of ALP. The pretreatment with RA followed by rh G-CSF treatment showed almost the same degree of ALP activity as that induced by the simultaneous treatment with RA and rhG-CSF. This study suggests that RA and rhG-CSF are the potent inducers of ALP activity o f HL-60 cells and protein kinase C is supposed to have a role in this induction of ALP.