title: Nonylphenol-induced Ca2+ elevation and Ca2+-independent cell death in human osteosarcoma cells.
abstract: The effect of the environmental toxicant nonylphenol on cytosolic free Ca2+ concentration ([Ca2+]i) and proliferation has not been explored in human osteoblast-like cells. This study examined whether nonylphenol alters Ca2+ levels and causes cell death in MG63 human osteosarcoma cells. [Ca2+]i and cell death were measured using the fluorescent dyes fura-2 and WST-1 respectively. Nonylphenol at concentrations above 3 microM increased [Ca2+]i in a concentration-dependent manner. The Ca2+ signal was reduced by 90% by removing extracellular Ca2+. The nonylphenol-induced Ca2+ influx was insensitive to blockade of L-type Ca2+ channel blockers. After pretreatment with 10 microM nonylphenol, 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) failed to induce [Ca2+]i rises. Inhibition of phospholipase C with 2 microM U73122 did not change nonylphenol-induced [Ca2+]i rises. The nonylphenol-induced [Ca2+]i rises were enhanced or inhibited by phorbol myristate acetate or GF 109203X, respectively. At concentrations of 10 and 20 microM nonylphenol killed 55% and 100% cells, respectively. The cytotoxic effect of 10 microM nonylphenol was unaltered by pre-chelating cytosolic Ca2+ with BAPTA. Collectively, in MG63 cells, nonylphenol induced [Ca2+]i rises by causing Ca2+ release from intracellular stores and Ca2+ influx from extracellular space. Furthermore, nonylphenol can cause Ca2+-unrelated cytotoxicity in a concentration-dependent manner.
authors: Department of Rehabilitation, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan, ROC.
authors: Jue-Long
authors: JL
authors: Wang
authors: Chung-Shin
authors: CS
authors: Liu
authors: Ko-Long
authors: KL
authors: Lin
authors: Chiang-Ting
authors: CT
authors: Chou
authors: Ching-Hong
authors: CH
authors: Hsieh
authors: Chih-Hung
authors: CH
authors: Chang
authors: Wei-Chuan
authors: WC
authors: Chen
authors: Shiuh-Inn
authors: SI
authors: Liu
authors: Shu-Shong
authors: SS
authors: Hsu
authors: Hong-Tai
authors: HT
authors: Chang
authors: Chung-Ren
authors: CR
authors: Jan
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000737:chemistry; D016257:Fura-2 / Q000031:analogs & derivatives / Q000737:chemistry; D006801:Humans; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D012516:Osteosarcoma; D010636:Phenols / Q000633:toxicity*; D011760:Pyrrolidinones / Q000494:pharmacology; D013050:Spectrometry, Fluorescence; D013778:Tetrazolium Salts / Q000737:chemistry; D019284:Thapsigargin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C110656:2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium; D002121:Calcium Channel Blockers; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D004963:Estrenes; D005456:Fluorescent Dyes; D010636:Phenols; D011760:Pyrrolidinones; D013778:Tetrazolium Salts; C049925:fura-2-am; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C074854:U 73343; D004533:Egtazic Acid; D019284:Thapsigargin; C025256:nonylphenol; D010738:Type C Phospholipases; D002118:Calcium; D016257:Fura-2