title: The regulation of human MMP-13 by licofelone, an inhibitor of cyclo-oxygenases and 5-lipoxygenase, in human osteoarthritic chondrocytes is mediated by the inhibition of the p38 MAP kinase signalling pathway.
abstract: BACKGROUND
  MMP-13 is one of the most important metalloproteases (MMP) involved in osteoarthritis. Licofelone, a novel dual inhibitor of cyclo-oxygenases (COX) and 5-lipoxygenase (5-LOX), can modulate MMP-13 production in human osteoarthritis chondrocytes.
  
  
  OBJECTIVE
  To evaluate the impact of licofelone on MMP-13 expression/production, promoter, and major MAP kinase signalling pathways and transcription factors.
  
  
  METHODS
  Human osteoarthritis chondrocytes were stimulated by interleukin 1beta (IL1beta) and treated with or without: licofelone (0.3, 1, or 3 mug/ml); NS-398 (10 muM; a specific COX-2 inhibitor); or BayX-1005 (10 muM; a specific 5-LOX inhibitor). MMP-13 synthesis was determined by specific enzyme linked immunosorbent assay, and expression by real time polymerase chain reaction. The effect of licofelone on the MMP-13 promoter was studied through transient transfection; dexamethasone (10(-7) M) was used as comparison. The effect on IL1beta induced MMP-13 signalling pathways was determined using specific ELISA for phosphorylated MAP kinases and transcription factors.
  
  
  RESULTS
  Licofelone dose dependently inhibited the IL1beta stimulated production and expression of MMP-13. NS-398 and BayX-1005 had very little effect. Licofelone also inhibited MMP-13 transcription on each of the promoter constructs used. The licofelone inhibition was comparable to that obtained with dexamethasone. Licofelone had no effect on phosphorylated p44/42 or JNK1/2; however, it decreased phosphorylated c-jun and inhibited phosphorylated p38, CREB, and AP-1 activity.
  
  
  CONCLUSIONS
  Licofelone inhibited MMP-13 production under proinflammatory conditions on human osteoarthritis chondrocytes, through inhibition of the p38/AP-1 pathway and the transcription factor CREB. This may explain some of the mechanisms whereby licofelone exerts its positive effect on osteoarthritic changes.
authors.affiliation: Osteoarthritis Research Unit, University of Montreal Hospital Centre, Notre-Dame Hospital, 1560 Sherbrooke St East, Montreal, Quebec, Canada H2L 4M1.
authors.forename: C
authors.initials: C
authors.lastname: Boileau
authors.forename: J-P
authors.initials: JP
authors.lastname: Pelletier
authors.forename: G
authors.initials: G
authors.lastname: Tardif
authors.forename: H
authors.initials: H
authors.lastname: Fahmi
authors.forename: S
authors.initials: S
authors.lastname: Laufer
authors.forename: M
authors.initials: M
authors.lastname: Lavigne
authors.forename: J
authors.initials: J
authors.lastname: Martel-Pelletier
mesh_terms: D000085:Acetates / Q000494:pharmacology*; D000368:Aged; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects*; D017364:Collagenases / Q000096:biosynthesis / Q000187:drug effects* / Q000235:genetics; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D016859:Lipoxygenase Inhibitors; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D053509:Matrix Metalloproteinase 13; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000201:enzymology* / Q000473:pathology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011758:Pyrroles / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000085:Acetates; D016861:Cyclooxygenase Inhibitors; D007375:Interleukin-1; D016859:Lipoxygenase Inhibitors; D011758:Pyrroles; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; D013755:Tetradecanoylphorbol Acetate; C088092:licofelone