title: Phosphorylation- and stimulus-dependent inhibition of cellular 5-lipoxygenase activity by nonredox-type inhibitors.
abstract: Nonredox-type 5-lipoxygenase (5-LO) inhibitors such as ZM230487 or L-739.010 potently suppress leukotriene biosynthesis at low cellular peroxide tone. Here, we show that inhibition of 5-LO product formation by nonredox-type 5-LO inhibitors in human isolated polymorphonuclear leukocytes (PMNL) depends on the activation pathway of 5-LO. Thus, compared with 5-LO product synthesis induced by the Ca2+-mobilizing agent ionophore A23187, cell stress-induced 5-LO product formation involving 5-LO kinase pathways required ~10- to 100-fold higher concentrations of ZM230487 or L-739.010 for comparable 5-LO inhibition. No such differences were observed for the iron ligand-type 5-LO inhibitor BWA4C or the novel-type 5-LO inhibitors hyperforin and 3-O-acetyl-11-keto-boswellic acid. Experiments using purified 5-LO revealed that Ca2+ is no prerequisite for potent enzyme inhibition by ZM230487, and exposure of PMNL to the combination of ionophore and cell stress did not restore potent 5-LO suppression. Intriguingly, a significant difference in the potency of nonredox-type inhibitors (but not of BWA4C) was determined between wild-type 5-LO and the mutant S271A/S663A-5-LO (lacking phosphorylation sites for ERK1/2 and MAPKAPK-2) in HeLa cells. Collectively, our data suggest that compared with Ca2+-mediated 5-LO product formation, enzyme activation involving 5-LO phosphorylation events specifically and strongly alters the susceptibility of 5-LO toward nonredox-type inhibitors in intact cells.
authors.affiliation: Institute of Pharmaceutical Chemistry, University of Frankfurt, Marie-Curie Strasse 9, D-60439 Frankfurt, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Fischer
authors.forename: Dagmar
authors.initials: D
authors.lastname: Szellas
authors.forename: Olof
authors.initials: O
authors.lastname: Rådmark
authors.forename: Dieter
authors.initials: D
authors.lastname: Steinhilber
authors.forename: Oliver
authors.initials: O
authors.lastname: Werz
mesh_terms: D001094:Arachidonate 5-Lipoxygenase / Q000235:genetics / Q000378:metabolism; D018053:Arsenites / Q000494:pharmacology; D044482:Benzeneacetamides; D001643:Bridged Bicyclo Compounds / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D020125:Mutation, Missense; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010545:Peroxides / Q000378:metabolism; D010696:Phloroglucinol / Q000031:analogs & derivatives; D010766:Phosphorylation; D011714:Pyrans / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D015363:Quinolones / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D017670:Sodium Compounds / Q000494:pharmacology; D013729:Terpenes / Q000494:pharmacology
chemical_list: D018053:Arsenites; D044482:Benzeneacetamides; D001643:Bridged Bicyclo Compounds; D004791:Enzyme Inhibitors; D006877:Hydroxamic Acids; C100577:L 739010; D016859:Lipoxygenase Inhibitors; D010545:Peroxides; D011714:Pyrans; D011804:Quinolines; D015363:Quinolones; D017670:Sodium Compounds; D013729:Terpenes; C056614:N-(3-phenoxycinnamyl)acetohydroxamic acid; C088450:ZM 230487; D000001:Calcimycin; D012965:Sodium Chloride; C017947:sodium arsenite; D010696:Phloroglucinol; D001094:Arachidonate 5-Lipoxygenase; D020928:Mitogen-Activated Protein Kinases; C001654:hyperforin; D002118:Calcium