SELECTIVE-INHIBITION OF CYCLOOXYGENASE-1 AND CYCLOOXYGENASE-2 USING INTACT INSECT-CELL ASSAYS

We have utilized the baculovirus expression system to develop an in vi tro intact cell assay for screening nonsteroidal anti-inflammatory dru g (NSAID) inhibition of the two isozymes of human cyclooxygenase (pros taglandin endoperoxidase synthase, EC 1.14.99.1). Infected Spodoptera frugiperda (sf9) cells expressing either human cyclooxygenase-1 (hCOX- 1) or human cyclooxygenase-2 (hCOX-2) were harvested 24 hr postinfecti on, a time point where all cells are viable and hCOX-1 or hCOX-2 are c orrectly processed. Cells were distributed to a 96-well plate, preincu bated with various NSAIDs, and challenged with 10 mu M arachidonic aci d; then cyclooxygenase activity was assessed indirectly by prostagland in E(2)-specific radioimmunoassay. The rank order of potency of NSAID- mediated inhibitions of hCOX-1 and hCOX-2 paralleled those that have b een observed in other cell systems. This sf9 cell-based assay can be u tilized for the identification of potent and selective inhibitors of h COX-1 and/or hCOX-2. Compounds that preferentially inhibit hCOX-2 may provide novelNSAIDs that reduce inflammation while sparing the stomach and kidneys of toxic side-effects seen with current nonselective NSAI Ds. Copyright (C) 1996 Elsevier Science Inc.