Genistein inhibits lysosomal enzyme release by suppressing Ca2+ influx in HL-60 granulocytes.
The tyrosine kinase inhibitor genistein (5-200 microM) suppressed Ca(2+)-dependent fMLP (1 microM) and ATP (100 microM)-induced release of the lysosomal enzyme, beta-glucuronidase from neutrophil-like HL-60 granulocytes. Agonist-induced Ca2+ mobilization resulted from the release of intracellular Ca2+ stores and the influx of extracellular Ca2+. Genistein (200 microM) suppressed fMLP (1 microM) and ATP (100 microM)-induced Ca2+ mobilization, by 30-40%. Ca2+ release from intracellular stores was unaffected by genistein, however, genistein abolished agonist-induced Ca2+ (Mn2+) influx. Consistent with these findings, genistein (200 microM) or removal of extracellular Ca2+ (EGTA 1 mM), inhibited Ca(2+)-dependent agonist-induced beta-glucuronidase release by similar extents (about 50%). In the absence of extracellular Ca2+, genistein had a small additional inhibitory effect on fMLP and ATP-induced beta-glucuronidase release, suggesting an additional inhibitory site of action. Genistein also abolished store-operated (thapsigargin-induced) Ca2+ (Mn2+) influx. Neither fMLP nor ATP increased the rate of Mn2+ influx induced by thapsigargin (0.5 microM). These data indicate that agonist-induced Ca2+ influx and store-operated Ca2+ influx occur via the same genistein-sensitive pathway. Activation of this pathway supports approximately 50% of lysosomal enzyme release induced by either fMLP or ATP from HL-60 granulocytes.
Foster
F M
FM
Department of Biochemistry, University of Sydney, NSW, Australia.
Conigrave
A D
AD
D000255:Adenosine Triphosphate / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism* / Q000494:pharmacology; D019833:Genistein / Q000378:metabolism* / Q000494:pharmacology; D005966:Glucuronidase / Q000378:metabolism*; D006098:Granulocytes / Q000166:cytology / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D008247:Lysosomes / Q000201:enzymology; D008345:Manganese / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors
D004791:Enzyme Inhibitors; D008345:Manganese; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000255:Adenosine Triphosphate; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D005966:Glucuronidase; D002118:Calcium