Expression of recombinant human cyclooxygenase isoenzymes in transfected COS-7 cells in vitro and inhibition by tenoxicam, indomethacin and aspirin.
The recent discovery of cyclooxygenase-2 (COX-2), an isoenzyme associated mainly with inflammation created the need to reevaluate cyclooxygenase inhibitors with reliable screening methods. In the present study we standardized a technique to determine the IC50S of cyclooxygenase inhibitors on recombinant human COX-1 and COX-2 expressed in mammalian cells and used it to study the compounds tenoxicam, aspirin and indomethacin. The IC50S of aspirin, indomethacin and tenoxicam for human COX-1 were 0.41 +/- 0.07 microgram/ml, 0.008 +/- 0.003 microgram/ml, and 7.94 +/- 3.28 micrograms/ml, respectively, and for human COX-20.64 +/- 0.16 microgram/ml, 0.09 +/- 0.05 microgram/ml, and 10.61 +/- 1.50 micrograms/ml, for aspirin, indomethacin, and tenoxicam. Tenoxicam had the lowest IC50hCOX-2/IC50hCOX-1 ratio (1.34), followed by aspirin (1.53) and indomethacin (10.82). The system described in the present study provides a simple and efficient way to determine the specificity of NSAID inhibition for each of the human cyclooxygenase isoenzymes separately.
Lora
M
M
Department of Pharmacology, Faculty of Medicine, Université de Sherbrooke, Fleurimont, PQ, Canada.
Morisset
S
S
Ménard
H A
HA
Leduc
R
R
de Brum-Fernandes
A J
AJ
D000818:Animals; D001241:Aspirin / Q000494:pharmacology*; D019556:COS Cells; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007213:Indomethacin / Q000494:pharmacology*; D007527:Isoenzymes / Q000187:drug effects* / Q000235:genetics; D008565:Membrane Proteins; D010894:Piroxicam / Q000031:analogs & derivatives* / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects* / Q000235:genetics; D011994:Recombinant Proteins / Q000187:drug effects; D014162:Transfection
D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D011994:Recombinant Proteins; D010894:Piroxicam; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D001241:Aspirin; D007213:Indomethacin; C032801:tenoxicam