Lipoxygenation of arachidonic acid by differentiated and undifferentiated human promyelocytic HL-60 cells.

The human promyelocytic leukemia cell line HL-60 can be induced to differentiate into mature granulocytes by exposure to dimethyl sulfoxide (DMSO), as well as into cells of monocyte-macrophage lineage by exposure to 12-0-tetra-decanoylphorbol-13-acetate (TPA). Incubation of the promyelocytic leukemic HL-60 cells and the two chemically induced differentiated cells with carbon 14-labeled arachidonic acid overnight resulted in the incorporation of label mainly into cellular phospholipids. Stimulation of the labeled cells with Ca2+ ionophore (A23187) resulted in the generation of lipoxygenase products in all the cells. Notably, the DMSO-induced differentiated granulocytic cells biosynthesized predominantly the peptidoeicosatetraenoic acids LTC4 and LTD4 compared with the dihydroxyeicosatetraenoic acid LTB4. On the other hand, the TPA-induced differentiated monocytic-macrophage cells biosynthesized predominantly LTB4 compared with LTC4 and LTD4. The undifferentiated promyelocytic cells lacked the capacity to biosynthesize LTB4, as evidenced in the chemically induced differentiated cells. The monohydroxyeicosatetraenoic acid (HETE) 5-HETE, a metabolite of the 5-lipoxygenase pathway, was a minor component in these cells, and 12-HETE and 15-HETE were barely detectable. These results suggest that the two models of DMSO-induced and TPA-induced differentiated cells may be useful systems for further investigations of arachidonic acid metabolites in granulocytic and monocytic-macrophage functions.