ACTIVATION OF NEUTROPHIL LIKE HL-60 CELLS BY PROSTAGLANDIN E(2)

The effect of prostaglandins on neutrophil activation has been studied using the human promyelocytic leukemic cell line HL-60, differentiate d with dimethyl sulfoxide (DMSO). Prostaglandin E(2) (PGE(2)) directly stimulated HL-60 cell aggregation with an EC(50) value of 30 nM. Stud ies with prostanoid receptor-selective agonists suggest that the activ ation of HL-60 cells by PGE, was mediated via the EP(2) receptor. Huma n neutrophils did not aggregate in response to PGE(2), but PGE(2) inhi bited the N-formyl-methionyl-leucyl-phenylalanine (FMLP)-stimulated in crease in intracellular calcium ([Ca2+](i)) in both neutrophils and HL -60 cells. In contrast with the aggregation response to FMLP, the aggr egation response of HL-60 cells to PGE(2) was independent of extracell ular calcium and did not involve mobilization of intracellular calcium .