Effects of the novel anti-inflammatory compounds, N-[2-(cyclohexyloxy)-4-nitrophenyl] methanesulphonamide (NS-398) and 5-methanesulphonamido-6-(2,4-difluorothio-phenyl)-1-inda none (L-745,337), on the cyclo-oxygenase activity of human blood prostaglandin endoperoxide synthases.
1. We have evaluated the selectivity of ketoprofen and two novel nonsteroidal anti-inflammatory drugs, N-[2-(cyclohexyloxy)-4-nitrophenyl]methanesulphonamide (NS-398) and 5-methanesulphonamido-6-(2,4-difluorothiophenyl)-1-indano ne (L-745,337), in inhibiting the cyclo-oxygenase activity of prostaglandin endoperoxide synthase-2 (PGHS-2) vs PGHS-1 in human blood monocytes and platelets, respectively. 2. Heparinized whole blood samples were drawn from healthy volunteers pretreated with aspirin, 300 mg 48 h before sampling, to suppress the activity of platelet PGHS-1 and incubated at 37 degrees C for 24 h with increasing concentrations of the test compounds in the presence of lipopolysaccharide (LPS, 10 micrograms ml-1). Immunoreactive PGE2 levels were measured in plasma by a specific radioimmunoassay as an index of the cyclo-oxygenase activity of LPS-induced monocyte PGHS-2. 3. The effects of the same inhibitors on platelet PGHS-1 activity were assessed by allowing whole blood samples, drawn from the same subjects in aspirin-free periods, to clot at 37 degrees C for 1 h in the presence of the compounds and measuring immunoreactive thromboxane B2 (TXB2) levels in serum by a specific radioimmunoassay. 4. Under these experimental conditions, ketoprofen enantioselectively inhibited the cyclo-oxygenase activity of both PGHS-1 and PGHS-2 with equal potency (IC50 ratio: approx. 0.5 for both enantiomers), while L-745,337 and NS-398 achieved selective inhibition of monocyte PGHS-2 (IC50 ratio: > 150). L-745,337 and NS-398 did not affect LPS-induced monocyte PGHS-2 biosynthesis to any detectable extent. 5. We conclude that L-745,337 and NS-398 are selective inhibitors of the cyclo-oxygenase activity of human monocyte PGHS-2. These compounds may provide adequate tools to test the contribution of this novel pathway of arachidonate metabolism to human inflammatory disease.
Panara
M R
MR
Department of Pharmacology, University of Chieti G. D'Annunzio School of Medicine, Italy.
Greco
A
A
Santini
G
G
Sciulli
M G
MG
Rotondo
M T
MT
Padovano
R
R
di Giamberardino
M
M
Cipollone
F
F
Cuccurullo
F
F
Patrono
C
C
D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology; D015153:Blotting, Western; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D015232:Dinoprostone / Q000096:biosynthesis / Q000097:blood; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007189:Indans / Q000494:pharmacology*; D007660:Ketoprofen / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000201:enzymology; D009578:Nitrobenzenes / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis / Q000097:blood*; D011485:Protein Binding; D013237:Stereoisomerism; D013449:Sulfonamides / Q000494:pharmacology*; D013929:Thromboxane B2 / Q000096:biosynthesis / Q000097:blood
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D007189:Indans; C093700:L 745337; D009578:Nitrobenzenes; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D013929:Thromboxane B2; D007660:Ketoprofen; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone