title: Epidermal growth factor receptor transactivation is required for proteinase-activated receptor-2-induced COX-2 expression in intestinal epithelial cells.
abstract: Proteinase-activated receptor (PAR)(2), a G protein-coupled receptor activated by serine proteinases, has been implicated in both intestinal inflammation and epithelial proliferation. Cyclooxygenase (COX)-2 is overexpressed in the gut during inflammation as well as in colon cancer. We hypothesized that PAR(2) drives COX-2 expression in intestinal epithelial cells. Treatment of Caco-2 colon cancer cells with the PAR(2)-activating peptide 2-furoyl-LIGRLO-NH(2) (2fLI), but not by its reverse-sequence PAR(2)-inactive peptide, for 3 h led to an increase in intracellular COX-2 protein expression accompanied by a COX-2-dependent increase in prostaglandin E(2) production. 2fLI treatment for 30 min significantly increased metalloproteinase activity in the culture supernatant. Increased epidermal growth factor receptor (EGFR) phosphorylation was observed in cell lysates following 40 min of treatment with 2fLI. The broad-spectrum metalloproteinase inhibitor marimastat inhibited both COX-2 expression and EGFR phosphorylation. The EGFR tyrosine kinase inhibitor PD153035 also abolished 2fLI-induced COX-2 expression. Although PAR(2) activation increased ERK MAPK phosphorylation, neither ERK pathway inhibitors nor a p38 MAPK inhibitor affected 2fLI-induced COX-2 expression. However, inhibition of either Src tyrosine kinase signaling by PP2, Rho kinase signaling by Y27632, or phosphatidylinositol 3 (PI3) kinase signaling by LY294002 prevented 2fLI-induced COX-2 expression. Trypsin increased COX-2 expression through PAR(2) in Caco-2 cells and in an EGFR-dependent manner in the noncancerous intestinal epithelial cell-6 cell line. In conclusion, PAR(2) activation drives COX-2 expression in Caco-2 cells via metalloproteinase-dependent EGFR transactivation and activation of Src, Rho, and PI3 kinase signaling. Our findings provide a mechanism whereby PAR(2) can participate in the progression from chronic inflammation to cancer in the intestine.
authors.affiliation: Dept. of Physiology and Pharmacology, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada.
authors.forename: Christina L
authors.initials: CL
authors.lastname: Hirota
authors.forename: France
authors.initials: F
authors.lastname: Moreau
authors.forename: Vadim
authors.initials: V
authors.lastname: Iablokov
authors.forename: Michael
authors.initials: M
authors.lastname: Dicay
authors.forename: Bernard
authors.initials: B
authors.lastname: Renaux
authors.forename: Morley D
authors.initials: MD
authors.lastname: Hollenberg
authors.forename: Wallace K
authors.initials: WK
authors.lastname: MacNaughton
mesh_terms: D066258:Amphiregulin; D015153:Blotting, Western; D018938:Caco-2 Cells; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D051546:Cyclooxygenase 2 / Q000096:biosynthesis* / Q000235:genetics; D015232:Dinoprostone / Q000378:metabolism; D066255:EGF Family of Proteins; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics / Q000502:physiology*; D006023:Glycoproteins / Q000032:analysis / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis / Q000378:metabolism; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D020782:Matrix Metalloproteinases / Q000096:biosynthesis; D058539:Phosphatidylinositol 3-Kinase / Q000502:physiology; D016133:Polymerase Chain Reaction; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology; D044464:Receptor, PAR-2 / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D015533:Transcriptional Activation / Q000187:drug effects; D014357:Trypsin / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D054460:rho-Associated Kinases / Q000502:physiology; D019061:src-Family Kinases / Q000502:physiology
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D034741:RNA, Small Interfering; D044464:Receptor, PAR-2; D051546:Cyclooxygenase 2; D058539:Phosphatidylinositol 3-Kinase; D066246:ErbB Receptors; D019061:src-Family Kinases; D054460:rho-Associated Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D014357:Trypsin; D020782:Matrix Metalloproteinases; D015232:Dinoprostone