Two opposing effects of non-steroidal anti-inflammatory drugs on the expression of the inducible cyclooxygenase. Mediation through different signaling pathways.
The efficacy of non-steroidal anti-inflammatory drugs (NSAIDs) is considered to be a result of their inhibitory effect on cyclooxygenase (COX) activity. Here, we report that flufenamic acid shows two opposing effects on COX-2 expression; it induces COX-2 expression in the colon cancer cell line (HT-29) and macrophage cell line (RAW 264.7); conversely, it inhibits tumor necrosis factor alpha (TNFalpha)- or lipopolysaccharide (LPS)-induced COX-2 expression. This inhibition correlates with the suppression of TNFalpha- or LPS-induced NFkappaB activation by flufenamic acid. The inhibitor of extracellular signal-regulated protein kinase, p38, or NFkappaB does not affect the NSAID-induced COX-2 expression. These results suggest that the NSAID-induced COX-2 expression is not mediated through activation of NFkappaB and mitogen-activated protein kinases. An activator of peroxisome proliferator-activated receptor gamma, 15-deoxy-Delta(12,14)-prostaglandin J(2), also induces COX-2 expression and inhibits TNFalpha-induced NFkappaB activation and COX-2 expression. Flufenamic acid and 15-deoxy-Delta(12,14)-prostaglandin J(2) also inhibit LPS-induced expression of inducible form of nitric-oxide synthase and interleukin-1alpha in RAW 264.7 cells. Together, these results indicate that the NSAIDs inhibit mitogen-induced COX-2 expression while they induce COX-2 expression. Furthermore, the results suggest that the anti-inflammatory effects of flufenamic acid and some other NSAIDs are due to their inhibitory action on the mitogen-induced expression of COX-2 and downstream markers of inflammation in addition to their inhibitory effect on COX enzyme activity.
Paik
J H
JH
Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana 70808, USA.
Ju
J H
JH
Lee
J Y
JY
Boudreau
M D
MD
Hwang
D H
DH
D000230:Adenocarcinoma; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D003110:Colonic Neoplasms; D051546:Cyclooxygenase 2; D004790:Enzyme Induction; D005439:Flufenamic Acid / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008264:Macrophages / Q000201:enzymology; D008565:Membrane Proteins; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D015230:Prostaglandin D2 / Q000031:analogs & derivatives / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis / Q000235:genetics*; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000502:physiology; D013467:Sulindac / Q000031:analogs & derivatives / Q000494:pharmacology; D014157:Transcription Factors / Q000187:drug effects / Q000502:physiology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000494:pharmacology*
C097240:15-deoxy-delta(12,14)-prostaglandin J2; D000894:Anti-Inflammatory Agents, Non-Steroidal; D007527:Isoenzymes; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D013467:Sulindac; D005439:Flufenamic Acid; C025462:sulindac sulfide; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015230:Prostaglandin D2