Coordinate up- and down-regulation of glutathione-dependent prostaglandin E synthase and cyclooxygenase-2 in A549 cells. Inhibition by NS-398 and leukotriene C4.
Recently, a microsomal protein with 38% sequence identity to microsomal glutathione S-transferase 1 was shown to constitute an inducible, glutathione-dependent prostaglandin E synthase (PGES). To investigate the relationship between cyclooxygenase and PGES, a time-course study on protein expression was performed in A549 cells after treatment with interleukin-1beta. The result demonstrated a tandem expression of cyclooxygenase-2 and PGES. The observed induction of PGES protein correlated with microsomal PGES activity. No comparable PGES activity was observed in the absence of glutathione or in the cytosolic fraction. In addition, tumour necrosis factor-alpha was found to induce PGES in these cells. Dexamethasone was found to completely suppress the effect of both cytokines on PGES induction. We also describe a quantitative method, based on RP-HPLC with UV detection for the measurements of PGES activity. This method was used to screen potential PGES inhibitors. Several nonsteroidal anti-inflammatory drugs, stable prostaglandin H2 analogues and cysteinyl leukotrienes were screened for inhibition of PGES activity. NS-398, sulindac sulfide and leukotriene C4 were all found to inhibit PGES activity with IC50 values of 20 microM, 80 microM and 5 microM, respectively. In conclusion, it appears that PGES and cyclooxygenase-2 are functionally coupled in A549 cells and that a required coordinate expression of these enzymes allows for efficient biosynthesis of prostaglandin E2.
Thorén
S
S
Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
Jakobsson
P J
PJ
D015153:Blotting, Western; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D019746:Intramolecular Oxidoreductases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017997:Leukotriene C4 / Q000494:pharmacology*; D008565:Membrane Proteins; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology; D009578:Nitrobenzenes / Q000494:pharmacology*; D000071876:Prostaglandin-E Synthases; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology*; D013467:Sulindac / Q000031:analogs & derivatives / Q000494:pharmacology; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D009578:Nitrobenzenes; D013449:Sulfonamides; D014409:Tumor Necrosis Factor-alpha; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D013467:Sulindac; D017997:Leukotriene C4; C025462:sulindac sulfide; D003907:Dexamethasone; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D019746:Intramolecular Oxidoreductases; D000071876:Prostaglandin-E Synthases; D005978:Glutathione