title: Effect of carvedilol on Ca2+ movement and cytotoxicity in human MG63 osteosarcoma cells.
abstract: Carvedilol is a useful cardiovascular drug for treating heart failure, however, the in vitro effect on many cell types is unclear. In human MG63 osteosarcoma cells, the effect of carvedilol on intracellular Ca2+ concentrations ([Ca2+]i) and cytotoxicity was explored by using fura-2 and tetrazolium, respectively. Carvedilol at concentrations greater than 1 microM caused a rapid rise in [Ca2+]i in a concentration-dependent manner (EC50=15 microM). Carvedilol-induced [Ca2+]i rise was reduced by 60% by removal of extracellular Ca2+. Carvedilol-induced Mn2+-associated quench of intracellular fura-2 fluorescence also suggests that carvedilol induced extracellular Ca2+ influx. 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 carvedilol on [Ca2+]i was inhibited by 50%. Conversely, pretreatment with carvedilol to deplete intracellular Ca2+ stores totally prevented thapsigargin from releasing more Ca2+. U73122, an inhibitor of phospholipase C, abolished histamine (an inositol 1,4,5-trisphosphate-dependent Ca2+ mobilizer)-induced, but not carvedilol-induced, [Ca2+]i rise. Pretreatment with phorbol 12-myristate 13-acetate and forskolin to activate protein kinase C and adenylate cyclase, respectively, did not alter carvedilol-induced [Ca2+]i rise. Separately, overnight treatment with 0.1-30 microM carvedilol inhibited cell proliferation in a concentration-dependent manner. These findings suggest that in human MG63 osteosarcoma cells, carvedilol increases [Ca2+]i by stimulating extracellular Ca2+ influx and also by causing intracellular Ca2+ release from the endoplasmic reticulum and other stores via a phospholipase C-independent manner. Carvedilol may be cytotoxic to osteoblasts.
authors.affiliation: Department of Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813. crjan@isca.vghks.gov.tw
authors.forename: Chun Peng
authors.initials: CP
authors.lastname: Liu
authors.forename: Chung-Ren
authors.initials: CR
authors.lastname: Jan
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D002227:Carbazoles / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D000077261:Carvedilol; D002451:Cell Compartmentation / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D005576:Colforsin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000187:drug effects; D004963:Estrenes / Q000494:pharmacology; D005453:Fluorescence; D016257:Fura-2 / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D006633:Histamine Antagonists / Q000494:pharmacology; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000502:physiology; D008345:Manganese / Q000378:metabolism / Q000494:pharmacology; D012516:Osteosarcoma / Q000473:pathology*; D010703:Phorbol Esters / Q000494:pharmacology; D011412:Propanolamines / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D013778:Tetrazolium Salts / Q000494:pharmacology; D019284:Thapsigargin / Q000037:antagonists & inhibitors / Q000494:pharmacology; D013997:Time Factors; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000502:physiology
chemical_list: D015220:Calcium Channels; D002227:Carbazoles; D004963:Estrenes; D006633:Histamine Antagonists; D010703:Phorbol Esters; D011412:Propanolamines; D011760:Pyrrolidinones; D013778:Tetrazolium Salts; D000077261:Carvedilol; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D005576:Colforsin; C119222:phorbol-12-myristate; D008345:Manganese; D019284:Thapsigargin; D006632:Histamine; D015544:Inositol 1,4,5-Trisphosphate; D011493:Protein Kinase C; D010738:Type C Phospholipases; D000262:Adenylyl Cyclases; D002118:Calcium; D016257:Fura-2