title: Novel effect of Y-24180, a presumed specific platelet activation factor receptor antagonist, on Ca2+ levels and growth of human prostate cancer cells.
abstract: In human prostate cancer PC3 cells, the effect of Y-24180, a presumed specific platelet activation factor (PAF) receptor antagonist, on intracellular Ca2+ concentration ([Ca2+]i) was measured by using fura-2 as a Ca2+-sensitive fluorescent probe. Y-24180 (1-10 microM) caused a rapid and sustained [Ca2+]i rise in a concentration-dependent manner. The [Ca2+]i rise was prevented by 40% by removal of extracellular Ca2+, but was not changed by dihydropyridines, verapamil and diltiazem. In Ca2+-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+-ATPase, caused a monophasic [Ca2+]i rise, after which the increasing effect of 10 microM Y-24180 on [Ca2+]i was reduced by 67%; conversely, depletion of Ca2+ stores with 10 microM Y-24180 abolished thapsigargin-induced [Ca2+]i rise. U73122, an inhibitor of phospholipase C, inhibited ATP-, but not Y-24180-induced [Ca2+]i rise. Activation of protein kinase C with phorbol-12-myristate-13-acetate (PMA) enhanced Y-24180-induced [Ca2+]i rise by 70%. Overnight treatment with 0.1-10 microM Y-24180 inhibited cell proliferation in a concentration-dependent manner. Collectively, these results suggest that Y-24180 acts as a potent and cytotoxic Ca2+ mobilizer in prostate cancer cells, by stimulating both extracellular Ca2+ influx and intracellular Ca2+ release. Since alterations in Ca2+ movement may interfere with many cellular signalling processes unrelated to modulation of PAF receptors, caution must be applied in using this reagent as a selective PAF receptor antagonist.
authors.affiliation: Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
authors.forename: Chung-Ren
authors.initials: CR
authors.lastname: Jan
authors.forename: Yu-Ying
authors.initials: YY
authors.lastname: Chao
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001381:Azepines / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects*; D004095:Dihydropyridines / Q000494:pharmacology; D004110:Diltiazem / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016257:Fura-2 / Q000737:chemistry; D006801:Humans; D008297:Male; D010703:Phorbol Esters / Q000494:pharmacology; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D019284:Thapsigargin / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014700:Verapamil / Q000494:pharmacology
chemical_list: D001381:Azepines; D004095:Dihydropyridines; D004791:Enzyme Inhibitors; D010703:Phorbol Esters; D010980:Platelet Membrane Glycoproteins; D043562:Receptors, G-Protein-Coupled; D014230:Triazoles; C039351:platelet activating factor receptor; C068035:4-(2-chlorophenyl)-2-(2-(4-isobutylphenyl)ethyl)-6,9-dimethyl-6H-thieno(3,2-f)(1,2,4)triazolo(4,3-a)(1,4)diazepine; D019284:Thapsigargin; D000255:Adenosine Triphosphate; D014700:Verapamil; D011493:Protein Kinase C; D004110:Diltiazem; D002118:Calcium; D016257:Fura-2