Effects of AF3442 [N-(9-ethyl-9H-carbazol-3-yl)-2-(trifluoromethyl)benzamide], a novel inhibitor of human microsomal prostaglandin E synthase-1, on prostanoid biosynthesis in human monocytes in vitro.
Inhibitors of microsomal prostaglandin (PG) E synthase-1 (mPGES-1) are being developed for the relief of pain. Redirection of the PGH(2) substrate to other PG synthases, found both in vitro and in vivo, in mPGES-1 knockout mice, may influence their efficacy and safety. We characterized the contribution of mPGES-1 to PGH(2) metabolism in lipopolysaccharide (LPS)-stimulated isolated human monocytes and whole blood by studying the synthesis of prostanoids [PGE(2), thromboxane (TX)B(2), PGF(2alpha) and 6-keto-PGF(1alpha)] and expression of cyclooxygenase (COX)-isozymes and down-stream synthases in the presence of pharmacological inhibition by the novel mPGES-1 inhibitor AF3442 [N-(9-ethyl-9H-carbazol-3-yl)-2-(trifluoromethyl)benzamide]. AF3442 caused a concentration-dependent inhibition of PGE(2) in human recombinant mPGES-1 with an IC(50) of 0.06microM. In LPS-stimulated monocytes, AF3442 caused a concentration-dependent reduction of PGE(2) biosynthesis with an IC(50) of 0.41microM. At 1microM, AF3442 caused maximal selective inhibitory effect of PGE(2) biosynthesis by 61+/-3.3% (mean+/-SEM, P<0.01 versus DMSO vehicle) without significantly affecting other prostanoids (i.e. TXB(2), PGF(2alpha) and 6-keto-PGF(1alpha)). In LPS-stimulated whole blood, AF3442 inhibited in a concentration-dependent fashion inducible PGE(2) biosynthesis with an IC(50) of 29microM. A statistically significant inhibition of mPGES-1 activity was detected at 10 and 100microM (38+/-14%, P<0.05, and 69+/-5%, P<0.01, respectively). Up to 100microM, the other prostanoids were not significantly affected. In conclusion, AF3442 is a selective mPGES-1 inhibitor which reduced monocyte PGE(2) generation also in the presence of plasma proteins. Pharmacological inhibition of mPGES-1 did not translate into redirection of PGH(2) metabolism towards other terminal PG synthases in monocytes. The functional relevance of this observation deserves to be investigated in vivo.
Bruno
Annalisa
A
Department of Medicine and Center of Excellence on Aging, School of Medicine, G. d'Annunzio University and G. d'Annunzio University Foundation, Ce.S.I., Chieti 66100, Italy.
Di Francesco
Luigia
L
Coletta
Isabella
I
Mangano
Giorgina
G
Alisi
Maria Alessandra
MA
Polenzani
Lorenzo
L
Milanese
Claudio
C
Anzellotti
Paola
P
Ricciotti
Emanuela
E
Dovizio
Melania
M
Di Francesco
Andrea
A
Tacconelli
Stefania
S
Capone
Marta L
ML
Patrignani
Paola
P
D001549:Benzamides / Q000494:pharmacology*; D002227:Carbazoles / Q000494:pharmacology*; D045744:Cell Line, Tumor; D015232:Dinoprostone / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D011464:Epoprostenol / Q000096:biosynthesis; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000037:antagonists & inhibitors*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology; D009000:Monocytes / Q000378:metabolism*; D044262:Prostaglandin H2 / Q000096:biosynthesis; D000071876:Prostaglandin-E Synthases; D011453:Prostaglandins / Q000096:biosynthesis*
C547396:AF 3442; D001549:Benzamides; D002227:Carbazoles; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D011453:Prostaglandins; D044262:Prostaglandin H2; D011464:Epoprostenol; D019746:Intramolecular Oxidoreductases; C000605862:PTGES protein, human; D000071876:Prostaglandin-E Synthases; C000605865:Ptges protein, mouse; D015232:Dinoprostone