title: Inhibition of phorbol ester-induced phenotypic differentiation of HL-60 cells by 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, a protein kinase inhibitor.
abstract: To identify the possible role of calcium ions in cell differentiation, we studied the extracellular Ca2+ requirement and the effect of Ca2+/phospholipid-dependent protein kinase (protein kinase C) inhibitor on proliferation and differentiation of human promyelocytic leukemic HL-60 cells. HL-60 cells grew equally well in 0.1 and 1.0 mM Ca2+ media. The addition of 12-O-tetradecanoyl-phorbol-13-acetate (TPA), 1,25-dihydroxyvitamin D3, and all-trans-beta-retinoic acid inhibited the cell growth and induced mature macrophage and granulocyte phenotypes in 1.0 mM Ca2+ medium. 1,25-Dihydroxyvitamin D3 and all-trans-beta-retinoic acid induced HL-60 differentiation to the same degree in 0.1 mM Ca2+ and 1.0 mM Ca2+ media. However, TPA failed to induce HL-60 differentiation or to inhibit proliferation in a 0.1 mM Ca2+ medium. The decrease of extracellular Ca2+ from 1.0 to 0.1 mM caused a significant drop in the intracellular Ca2+ level in undifferentiated and TPA-treated HL-60 cells, although no rapid change in cytosolic Ca2+ was detected in response to TPA addition. 1-(5-Isoquinolinylsulfonyl)-2-methylpiperazine (H-7), a protein kinase C inhibitor, inhibited proliferation of HL-60 cells in a dose-dependent manner. In contrast, H-7 selectively restored the proliferation of TPA-treated HL-60 cells and inhibited TPA-induced phenotypic differentiation. However, the same concentrations of 1-(5-isoquinolinylsulfonyl)-2,3-dimethylpiperazin and N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide, analogues of H-7 that inhibit protein kinase C more weakly, had no effect on the proliferation or differentiation induction. H-7 also suppressed 1,25-dihydroxyvitamin D3- and all-trans-beta-retinoic acid-induced phenotypic changes of HL-60 cells but did not eliminate the growth inhibition by these inducers. These results demonstrate the Ca2+ requirement and the protein kinase C involvement in phorbol ester-induced phenotypic differentiation of HL-60 cells.
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000098:Acetophenones / Q000494:pharmacology; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis; D002117:Calcitriol / Q000494:pharmacology; D002118:Calcium / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D003600:Cytosol / Q000502:physiology; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology*; D010703:Phorbol Esters / Q000037:antagonists & inhibitors*; D010879:Piperazines / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors; D045162:Thiazolidinediones; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D000098:Acetophenones; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007546:Isoquinolines; D010703:Phorbol Esters; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D045162:Thiazolidinediones; C001995:5-carboxymethyl-3-p-tolylthiazolidine-2,4-dione-2-acetophenone; D014212:Tretinoin; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D002117:Calcitriol; D002118:Calcium