title: Comparison of tBuBHQ with chemotactic peptide and phorbol ester in O2- production in HL-60 cells.
abstract: The effect of 2,5-di-(tert-butyl)-1,4-benzohydroquinone (tBuBHQ), a Ca2+ pump inhibitor, on superoxide anion (O2-) production was examined with a special reference to Ca2+ in HL-60 cells differentiated by dibutyryl cAMP, and compared with the effect of N-formyl-Met-Leu-Phe (fMLP) and phorbol 12-myristate 13-acetate (PMA). tBuBHQ caused O2- production and Ca2+ mobilization, but not phosphoinositide hydrolysis. fMLP caused O2- production, Ca2+ mobilization and phosphoinositide hydrolysis. PMA caused O2- production without affecting Ca2+ mobilization and phosphoinositide hydrolysis. EGTA and O,O'-bis(2-aminophenyl)ethyleneglycol- N,N,N',N'-tetraacetic acid, tetraacetoxymethyl ester (BAPTA/AM), an intracellular Ca2+ chelator, inhibited O2- production induced by fMLP, but not by tBuBHQ. Thapsigargin, another Ca2+ pump inhibitor, had a weak ability to produce O2-. fMLP, but not tBuBHQ, caused BAPTA/AM-sensitive activation of phospholipase A2 and D. tBuBHQ caused O2- production by interacting with phosphatidylcholine in a cell-free system. The results suggest that tBuBHQ causes O2- production independent of Ca2+, and Ca2+ might be a cofactor in the activation of phospholipase A2 and D upstream in fMLP-induced O2- production.
authors.affiliation: Department of Pharmaceutical Molecular Biology, Tohoku University, Sendai, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tsukii
authors.forename: N
authors.initials: N
authors.lastname: Nakahata
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: S
authors.initials: S
authors.lastname: Tsurufuji
authors.forename: Y
authors.initials: Y
authors.lastname: Ohizumi
mesh_terms: D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D018922:HL-60 Cells / Q000378:metabolism; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D010741:Phospholipases A / Q000502:physiology; D054467:Phospholipases A2; D013481:Superoxides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D006873:Hydroquinones; D013481:Superoxides; C019359:2,5-di-tert-butylhydroquinone; D004533:Egtazic Acid; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010741:Phospholipases A; D054467:Phospholipases A2; D000252:Calcium-Transporting ATPases; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium