Cigarette smoke extract induces COX-2 expression via a PKCalpha/c-Src/EGFR, PDGFR/PI3K/Akt/NF-kappaB pathway and p300 in tracheal smooth muscle cells

Am J Physiol Lung Cell Mol Physiol. 2009 Nov;297(5):L892-902. doi: 10.1152/ajplung.00151.2009. Epub 2009 Aug 28.

Abstract

Exposure to cigarette smoke extract (CSE) leads to airway or lung inflammation, which may be mediated through cyclooxygenase-2 (COX-2) expression and its product prostaglandin E2 (PGE2) synthesis. The aim of this study was to investigate the molecular mechanisms underlying CSE-induced COX-2 expression in human tracheal smooth muscle cells (HTSMCs). Here, we describe that COX-2 induction is dependent on PKCalpha/c-Src/EGFR, PDGFR/PI3K/Akt/NF-kappaB signaling in HTSMCs. CSE stimulated the phosphorylation of c-Src, EGFR, PDGFR, and Akt, which were inhibited by pretreatment with the inhibitor of PKCalpha (Gö6976 or Gö6983), c-Src (PP1), EGFR (AG1478), PDGFR (AG1296), or PI3K (LY294002). Moreover, CSE induced a significant increase in COX-2 expression, which was reduced by pretreatment with these inhibitors or transfection with siRNA of PKCalpha, Src, or Akt. Furthermore, CSE-stimulated NF-kappaB p65 phosphorylation and translocation were also attenuated by pretreatment with Gö6976, PP1, AG1478, AG1296, or LY294002. CSE-induced COX-2 expression was also mediated through the recruitment of p300 associated with NF-kappaB in HTSMCs, revealed by coimmunoprecipitation and Western blot analysis. In addition, pretreatment with the inhibitors of NF-kappaB (helenalin) and p300 (garcinol) or transfection with p65 siRNA and p300 siRNA markedly inhibited CSE-regulated COX-2 expression. However, CSE-induced PGE2 generation was reduced by pretreatment with the inhibitor of COX-2 (NS-398). These results demonstrated that in HTSMCs, CSE-induced COX-2-dependent PGE2 generation was mediated through PKCalpha/c-Src/EGFR, PDGFR/PI3K/Akt leading to the recruitment of p300 with NF-kappaB complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cyclooxygenase 2 / biosynthesis*
  • Dinoprostone / biosynthesis
  • E1A-Associated p300 Protein / metabolism*
  • Enzyme Induction
  • ErbB Receptors / metabolism
  • Humans
  • Models, Biological
  • Myocytes, Smooth Muscle / enzymology*
  • NF-kappa B / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Protein Binding
  • Protein Kinase C-alpha / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Receptors, Platelet-Derived Growth Factor / metabolism
  • Signal Transduction*
  • Smoke* / adverse effects
  • Smoking / metabolism*
  • Trachea / cytology*
  • Up-Regulation
  • src-Family Kinases / metabolism

Substances

  • NF-kappa B
  • Smoke
  • Cyclooxygenase 2
  • PTGS2 protein, human
  • E1A-Associated p300 Protein
  • EP300 protein, human
  • Phosphatidylinositol 3-Kinases
  • ErbB Receptors
  • Receptors, Platelet-Derived Growth Factor
  • src-Family Kinases
  • Proto-Oncogene Proteins c-akt
  • Protein Kinase C-alpha
  • Dinoprostone