title: Studies of the inhibitory activity of MK-0591 (3-[1-(4-chlorobenzyl)-3-(t-butylthio)-5-(quinolin-2-yl-methoxy)-indol- 2-yl]-2,2-dimethyl propanoic acid) on arachidonic acid metabolism in human phagocytes.
abstract: We have investigated the inhibitory activity of compound MK-0591 (3-[1-(4-chlorobenzyl)-3-(t-butylthio)-5-(quinolin-2-yl-methoxy)-i ndol-2- yl]-2,2-dimethyl propanoic acid) on 5-lipoxygenase (5-LO) product synthesis in various human phagocytes stimulated with either the ionophore A23187, opsonized zymosan (OPZ), platelet-activating factor (PAF), or formyl-methionyl-leucyl-phenylalanine (fMLP). The lipoxygenase products were analyzed by reversed-phase HPLC. MK-0591 inhibited the formation of 5-hydroxyeicosatetraenoic acid, leukotriene (LT) B4, its omega-oxidation products, and 6-trans-isomers with IC50 values of 2.8-4.8 nM in A23187-stimulated neutrophils. In these conditions, arachidonic acid at a concentration of 10 microM had no effect on MK-0591 inhibitory activity. In neutrophils stimulated with OPZ, the synthesis of LTB4, its omega-oxidation products, and 6-trans-isomers was inhibited with IC50 values of 9.5-11.0 nM. MK-0591 inhibited 5-LO product synthesis in A23187-stimulated blood monocytes, eosinophils, and alveolar macrophages with IC50 values of 0.3-0.9, 3.7-5.3, and 8.5-17.3 nM, respectively. In neutrophils primed with granulocyte--macrophage colony-stimulating factor and stimulated with PAF, lipoxygenase product synthesis was inhibited with IC50 values of 7.7-8.7 nM. At the concentration of 1 microM, MK-0591 had no inhibitory effect on 15-lipoxygenase activity in human polymorphonuclear leukocytes, nor on human platelet 12-lipoxygenase and cyclooxygenase. In conclusion, MK-0591 is a very potent and specific inhibitor of 5-LO product synthesis in various types of human phagocytes.
authors.affiliation: Unité de recherche inflammation et immunologie-rhumatologie, Centre hospitalier de l'Université Laval, Ste-Foy (Québec), Canada.
authors.forename: L
authors.initials: L
authors.lastname: Ménard
authors.forename: M
authors.initials: M
authors.lastname: Laviolette
authors.forename: P
authors.initials: P
authors.lastname: Borgeat
mesh_terms: D000328:Adult; D016718:Arachidonic Acid / Q000097:blood / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D003864:Depression, Chemical; D004804:Eosinophils / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000097:blood / Q000494:pharmacology*; D015289:Leukotrienes / Q000096:biosynthesis / Q000097:blood; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism; D010586:Phagocytes / Q000187:drug effects* / Q000378:metabolism; D011804:Quinolines / Q000097:blood / Q000494:pharmacology*
chemical_list: D007211:Indoles; D015289:Leukotrienes; D011804:Quinolines; C078266:MK 0591; D016718:Arachidonic Acid; D000001:Calcimycin