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.
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.
Yang
Chuen-Mao
CM
Department of Pharmacology, Chang Gung University, Chang Gung Memorial Hospital, 259 Wen-Hwa 1st Road, Kwei-San, Tao-Yuan, Taiwan. chuenmao@mail.cgu.edu.tw
Lee
I-Ta
IT
Lin
Chih-Chung
CC
Yang
Ya-Lin
YL
Luo
Shue-Fen
SF
Kou
Yu Ru
YR
Hsiao
Li-Der
LD
D002460:Cell Line; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D015232:Dinoprostone / Q000096:biosynthesis; D050881:E1A-Associated p300 Protein / Q000378:metabolism*; D004790:Enzyme Induction; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D032389:Myocytes, Smooth Muscle / Q000201:enzymology*; D016328:NF-kappa B / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011485:Protein Binding; D051571:Protein Kinase C-alpha / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism; D015398:Signal Transduction; D012906:Smoke / Q000009:adverse effects; D012907:Smoking / Q000378:metabolism*; D014132:Trachea / Q000166:cytology*; D015854:Up-Regulation; D019061:src-Family Kinases / Q000378:metabolism
D016328:NF-kappa B; D012906:Smoke; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D050881:E1A-Associated p300 Protein; C494360:EP300 protein, human; D019869:Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors; D017479:Receptors, Platelet-Derived Growth Factor; D019061:src-Family Kinases; D051057:Proto-Oncogene Proteins c-akt; D051571:Protein Kinase C-alpha; D015232:Dinoprostone