Regulation of Cyclooxygenase-2 by Interferon γ and Transforming Growth Factor α in Normal Human Epidermal Keratinocytes and Squamous Carcinoma Cells
1999; Elsevier BV; Volume: 274; Issue: 41 Linguagem: Inglês
10.1074/jbc.274.41.29138
ISSN1083-351X
AutoresHironori Matsuura, Morito Sakaue, Kotha Subbaramaiah, Hideki Kamitani, Thomas E. Eling, Andrew J. Dannenberg, Tadashi Tanabe, Hiroyasu Inoue, Jirô Arata, Anton M. Jetten,
Tópico(s)Estrogen and related hormone effects
ResumoTreatment of normal human epidermal keratinocytes (NHEK) with interferon-γ (IFN-γ) causes a 9-fold increase in the level of cyclooxygenase-2 (COX-2) mRNA expression. Nuclear run-off assays indicate that this induction is at least partly due to increased transcription. Activation of the epidermal growth factor receptor (EGFR) signaling pathway due to the enhanced transforming growth factor α (TGFα) expression plays an important role in the induction of COX-2 by IFN-γ. This is supported by the ability of TGFα to rapidly induce COX-2 and the inhibition of the IFN-γ-mediated COX-2 mRNA induction by an EGFR antibody and EGFR-selective kinase inhibitors. Deletion and mutation analysis indicates the importance of the proximal cAMP-response element/ATF site in the transcriptional control of this gene by TGFα. The increase in COX-2 mRNA by TGFα requires activation of both the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) pathways. Inhibition of p38 MAPK decreases the stability of COX-2 mRNA, while inhibition of MAPK/ERK kinase (MEK) does not. These results suggest that the p38 MAPK signaling pathway controls COX-2 at the level of mRNA stability, while the ERK signaling pathway regulates COX-2 at the level of transcription. In contrast to NHEK, IFN-γ and TGFα are not very effective in inducing TGFα or COX-2 expression in several squamous carcinoma cell lines, indicating alterations in both IFN-γ and TGFα response pathways. Treatment of normal human epidermal keratinocytes (NHEK) with interferon-γ (IFN-γ) causes a 9-fold increase in the level of cyclooxygenase-2 (COX-2) mRNA expression. Nuclear run-off assays indicate that this induction is at least partly due to increased transcription. Activation of the epidermal growth factor receptor (EGFR) signaling pathway due to the enhanced transforming growth factor α (TGFα) expression plays an important role in the induction of COX-2 by IFN-γ. This is supported by the ability of TGFα to rapidly induce COX-2 and the inhibition of the IFN-γ-mediated COX-2 mRNA induction by an EGFR antibody and EGFR-selective kinase inhibitors. Deletion and mutation analysis indicates the importance of the proximal cAMP-response element/ATF site in the transcriptional control of this gene by TGFα. The increase in COX-2 mRNA by TGFα requires activation of both the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) pathways. Inhibition of p38 MAPK decreases the stability of COX-2 mRNA, while inhibition of MAPK/ERK kinase (MEK) does not. These results suggest that the p38 MAPK signaling pathway controls COX-2 at the level of mRNA stability, while the ERK signaling pathway regulates COX-2 at the level of transcription. In contrast to NHEK, IFN-γ and TGFα are not very effective in inducing TGFα or COX-2 expression in several squamous carcinoma cell lines, indicating alterations in both IFN-γ and TGFα response pathways. interferon intercellular adhesion molecule normal human epidermal keratinocyte(s) cyclooxygenase hydroxyeicosatetraenoic acid prostaglandin E2 high performance liquid chromatography transforming growth factor α epidermal growth factor EGF receptor mitogen-activated protein MAP kinase extracellular signal-regulated kinase mitogen-activated protein kinase/ERK kinase glyceraldehyde-3-phosphate dehydrogenase cAMP-response element CCAAT/enhancer-binding protein phosphate-buffered saline signal transducers and activators of transcription peroxisome proliferator-activated receptor The epidermis functions as a barrier to transepidermal water loss and defense against physical damage, microbes, UV light and xenobiotics (1Holbrook K. Leigh I.M. Lane E.B. Watt F.M. The Keratinocyte Handbook. Cambridge University Press, Cambridge1994: 3-42Google Scholar, 2Fuchs E. Byrne C. Curr. Opin. Genet. Dev. 1994; 4: 725-736Crossref PubMed Scopus (222) Google Scholar, 3Elias P.M. Exp. Dermatol. 1996; 5: 191-201Crossref PubMed Scopus (109) Google Scholar, 4Jetten A.M. Harvat B.L. J. Dermatol. 1997; 24: 711-725Crossref PubMed Scopus (41) Google Scholar, 5Eckert R.L. Crish J.F. Robinson N.A. Physiol. Rev. 1997; 77: 397-424Crossref PubMed Scopus (341) Google Scholar). Differentiation in the epidermis begins with migration of basal cells into the spinous layer, followed by transit of the cells into the granular layer and subsequently into the stratum corneum (2Fuchs E. Byrne C. Curr. Opin. Genet. Dev. 1994; 4: 725-736Crossref PubMed Scopus (222) Google Scholar, 5Eckert R.L. Crish J.F. Robinson N.A. Physiol. Rev. 1997; 77: 397-424Crossref PubMed Scopus (341) Google Scholar, 6Jones P.H. Harper S. Watt F.M. Cell. 1995; 80: 83-93Abstract Full Text PDF PubMed Scopus (719) Google Scholar, 7Tennenbaum T. Li L. Belanger A.J. De Luca L.M. Yuspa S.H. Cell Growth Differ. 1997; 7: 615-628Google Scholar). Each of these stages is associated with induction of specific differentiation markers, including various keratins, transglutaminases, cornifin, and loricrin (4Jetten A.M. Harvat B.L. J. Dermatol. 1997; 24: 711-725Crossref PubMed Scopus (41) Google Scholar, 5Eckert R.L. Crish J.F. Robinson N.A. Physiol. Rev. 1997; 77: 397-424Crossref PubMed Scopus (341) Google Scholar, 7Tennenbaum T. Li L. Belanger A.J. De Luca L.M. Yuspa S.H. Cell Growth Differ. 1997; 7: 615-628Google Scholar, 8Marvin K. George M.A. Saunders N. Bernacki S. Fujimoto W. Jetten A.M. Proc. Natl. Acad. Sci. U. S. A. 1992; 89: 11026-11030Crossref PubMed Scopus (146) Google Scholar, 9Phillips M.A. Stewart B.E. Qin Q. Chakravarti R. Floyd E.E. Jetten A.M. Rice R.H. Proc. Natl. Acad. Sci. U. S. A. 1990; 87: 9333-9337Crossref PubMed Scopus (102) Google Scholar, 10Floyd E.E. Jetten A.M. Mol. Cell. Biol. 1989; 9: 4846-4851Crossref PubMed Scopus (103) Google Scholar, 11Mehrel T. Hohl D. Rothnagel J.A. Longley M.A. Bundman D. Cheng C. Lichti U. Bisher M.E. Steven A.C. Steinert P.M. Yuspa S.H. Roop D.R. Cell. 1990; 61: 1103-1112Abstract Full Text PDF PubMed Scopus (379) Google Scholar). Homeostasis in the epidermis is maintained by a balance between cellular proliferation, differentiation, and apoptosis (2Fuchs E. Byrne C. Curr. Opin. Genet. Dev. 1994; 4: 725-736Crossref PubMed Scopus (222) Google Scholar, 5Eckert R.L. Crish J.F. Robinson N.A. Physiol. Rev. 1997; 77: 397-424Crossref PubMed Scopus (341) Google Scholar, 12Polakowska R.R. Piacentini M. Bartlett R. Goldsmith L.A. Haake A.R. Dev. Dyn. 1994; 199: 176-188Crossref PubMed Scopus (249) Google Scholar). A variety of different signals, including several hormones and many cytokines, have been identified that influence these biological processes through autocrine, paracrine, or endocrine mechanisms (13Matue H. Cruz P.D. Bregstresser P.R. Takashima A. J. Invest. Dermatol. 1992; 99: 42S-45SAbstract Full Text PDF PubMed Scopus (85) Google Scholar, 14Nickoloff B.J. Arch. Dermatol. 1991; 127: 871-884Crossref PubMed Scopus (318) Google Scholar, 15Saunders N.A. Jetten A.M. J. Biol. Chem. 1994; 269: 2016-2022Abstract Full Text PDF PubMed Google Scholar, 16Yuspa S.H. Ben T. Lichti U. Cancer Res. 1983; 43: 5707-5712PubMed Google Scholar, 17Marks F. Fürstenberger G. Environ. Health Perspect. 1993; 95: 95-102Google Scholar, 18Komuves L.G. Hanley K. Jiang Y. Elias P.M. Williams M.L. Feingold K.R. J. Invest. Dermatol. 1998; 111: 429-433Abstract Full Text Full Text PDF PubMed Scopus (95) Google Scholar, 19Coffey R.J. Derynck R. Wilcox J.N. Bringman T.S. Goustin A.S. Moses H.L. Pittelkow M.R. Nature. 1987; 328: 817-820Crossref PubMed Scopus (686) Google Scholar). Dysregulation of the cytokine network has been implicated in many cutaneous diseases, including cancer and several inflammatory processes (14Nickoloff B.J. Arch. Dermatol. 1991; 127: 871-884Crossref PubMed Scopus (318) Google Scholar, 15Saunders N.A. Jetten A.M. J. Biol. Chem. 1994; 269: 2016-2022Abstract Full Text PDF PubMed Google Scholar, 20Elder J.T. Fisher G.J. Lindquist P.B. Bennett G.L. Pittelkow M.R. Coffey R.J. Ellingsworth L. Derynck R. Voorhees J.J. Science. 1989; 243: 811-814Crossref PubMed Scopus (501) Google Scholar,21Glick A.B. Sporn M.B. Yuspa S.H. Mol. Carcinog. 1991; 4: 210-219Crossref PubMed Scopus (83) Google Scholar).IFN-γ1 is a proinflammatory cytokine that is principally produced by activated T-lymphocytes and natural killer cells and affects a vast array of different cellular processes. IFN-γ has also been reported to affect growth and differentiation in cultured epidermal keratinocytes (14Nickoloff B.J. Arch. Dermatol. 1991; 127: 871-884Crossref PubMed Scopus (318) Google Scholar, 15Saunders N.A. Jetten A.M. J. Biol. Chem. 1994; 269: 2016-2022Abstract Full Text PDF PubMed Google Scholar, 22Naik S.M. Shibagaki N. Li L-J. Quinlan K.L. Paxton L.L. Caughman S.W. J. Biol. Chem. 1997; 272: 1283-1290Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 23Tamai K. Li K. Silos S. Rudnicka L. Hashimoto T. Nishikawa T. Uitto J. J. Biol. Chem. 1995; 270: 392-396Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar, 24Fransson J. Shen Q. Scheynius A. Hammar H. Arch. Dermatol. Sci. 1996; 289: 14-20Google Scholar, 25Nickoloff B.J. Mitra R.S. Elder J.T. Fisher G.J. Voorhees J.J. Br. J. Dermatol. 1989; 121: 161-174Crossref PubMed Scopus (103) Google Scholar) and has been implicated in several inflammatory skin diseases, such as allergic contact dermatitis and psoriasis (14Nickoloff B.J. Arch. Dermatol. 1991; 127: 871-884Crossref PubMed Scopus (318) Google Scholar, 26Fierlbeck G. Rasner G. Muler G. Arch. Dermatol. 1990; 126: 315-355Crossref Scopus (170) Google Scholar, 27Carroll J.M. Crompton T. Seery J.P. Watt F.M. J. Invest. Dermatol. 1997; 108: 412-422Abstract Full Text PDF PubMed Scopus (139) Google Scholar, 28Gomi T. Siohara T. Munasaka T Imanish K. Nagashima M. Arch. Dermatol. 1991; 127: 827-830Crossref PubMed Scopus (88) Google Scholar, 29Barker J.N.W.N. Mitra R.S. Griffiths C.E.M. Dixit V.M. Nickoloff B.J. Lancet. 1991; 337: 211-214Abstract PubMed Scopus (635) Google Scholar). Sites of inflammation contain elevated levels of IFN-γ and intercellular adhesion molecule-1 (ICAM-1), which plays a pivotal role in the adhesion and migration of leukocytes at sites of inflammation, and ICAM-1 is dramatically induced by IFN-γ in epidermal keratinocytes (26Fierlbeck G. Rasner G. Muler G. Arch. Dermatol. 1990; 126: 315-355Crossref Scopus (170) Google Scholar). Recent studies showed that targeted expression of IFN-γ to the suprabasal layers of the epidermis of transgenic mice induces increased proliferation, a thickened epidermis, perturbed differentiation, and eczema resembling contact dermatitis (27Carroll J.M. Crompton T. Seery J.P. Watt F.M. J. Invest. Dermatol. 1997; 108: 412-422Abstract Full Text PDF PubMed Scopus (139) Google Scholar). These results demonstrate the importance of IFN-γ in the regulation of inflammation and cellular proliferation and differentiation in the skin.Prostaglandins also play a major role in the induction of inflammatory processes in the epidermis and in the control of proliferation and differentiation of keratinocytes (30Fürstenberger G. Cell Biol. Rev. 1990; 24: 1-111PubMed Google Scholar, 31Konger R.L. Malaviya R. Pentland A.P. Biochim. Biophys. Acta. 1998; 1401: 221-234Crossref PubMed Scopus (83) Google Scholar, 32Evans C.B. Pillai S. Goldyne M.E. Prostaglandins Leukotrienes Essent. Fatty Acids. 1993; 49: 777-781Abstract Full Text PDF PubMed Scopus (41) Google Scholar, 33Miller C.C. Hale P. Pentland A.P. J. Biol. Chem. 1994; 269: 3529-3533Abstract Full Text PDF PubMed Google Scholar, 34Leong J. Hughes-Fulford M. Rakhlin N. Habib A. Maclouf J. Goldyne M.E. Exp. Cell. Res. 1996; 224: 79-87Crossref PubMed Scopus (117) Google Scholar). Cyclooxygenases (COX-1 and COX-2) catalyze the first, rate-limiting step in the conversion of arachidonic acid into prostaglandins and thromboxanes. COX-1 is constitutively expressed in a wide variety of tissues, including the epidermis, while COX-2 is a highly inducible gene that is expressed in response to a variety of proinflammatory agents and cytokines (35Herschman H.R. Cancer Metastasis Rev. 1994; 13: 241-256Crossref PubMed Scopus (315) Google Scholar, 36Bates E.J. Prostaglandins Leukotrienes Essent. Fatty Acids. 1995; 53: 75-86Abstract Full Text PDF PubMed Scopus (32) Google Scholar, 37Crofford L.J. J. Rheumatol. 1997; 49: 15-19Google Scholar, 38Ristimäki A. Garfinkel S. Wessendorf J. Maciag T. Hla T. J. Biol. Chem. 1994; 269: 11769-11775Abstract Full Text PDF PubMed Google Scholar, 39Grewe M. Gyufko K. Krutmann J. J. Invest. Dermatol. 1995; 104: 3-6Abstract Full Text PDF PubMed Scopus (178) Google Scholar, 40Mestre J.R. Subbaramaiah K. Sacks P.G. Schantz S.P. Tanabe T. Inoue H. Dannenberg A.J. Cancer Res. 1997; 57: 2890-2895PubMed Google Scholar, 41Pang L. Knox A.J. Br. J. Pharmacol. 1997; 121: 579-587Crossref PubMed Scopus (160) Google Scholar, 42Asano K. Nakamura H. Lilly C.M. Klagsbrun M. Drazen J.M. J. Clin. Invest. 1997; 99: 1057-1063Crossref PubMed Scopus (45) Google Scholar, 43Inoue H. Yokoyama C. Hara S. Tone Y. Tanabe T. J. Biol. Chem. 1995; 270: 24965-24971Abstract Full Text Full Text PDF PubMed Scopus (467) Google Scholar). The tumor promoter 12-tetradecanoylphorbol-13-myristate, epidermal growth factor, and UV irradiation have been shown to induce COX-2 in epidermal keratinocytes and in the epidermis (44Buckman S.Y. Gresham A. Hale P. Hruza G. Anast J. Masferrer J. Pentland A.P. Carcinogenesis. 1998; 19: 723-729Crossref PubMed Scopus (507) Google Scholar, 45Loftin C.D. Eling T.E. Arch. Biochem. Biophys. 1996; 330: 419-429Crossref PubMed Scopus (21) Google Scholar, 46Maldve R.E. Fischer S.M. Mol. Carcinog. 1996; 17: 207-216Crossref PubMed Scopus (32) Google Scholar). In addition to sites of inflammation, elevated COX-2 expression has also been found in many tumors, including skin (47Kutchera W. Jones D.A. Matsunami N. Groden J. McIntyre T.M. Zimmerman G.A. White R.L. Prescott S.M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 4816-4820Crossref PubMed Scopus (445) Google Scholar, 48Müller-Decker K. Scholz K. Marks F. Fürstenberger G. Mol. Carcinog. 1995; 12: 31-41Crossref PubMed Scopus (137) Google Scholar, 49Tsujii M. Kawano S. DuBois R.N. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 3336-3340Crossref PubMed Scopus (1325) Google Scholar). The COX-inhibitor indomethacin has been reported to suppress tumor formation in the skin (50Fürstenberger G. Gross M. Marks F. Carcinogenesis. 1989; 10: 91-96Crossref PubMed Scopus (101) Google Scholar), and COX-2 null mice developed 75% fewer chemically induced skin papillomas than control mice (51Tiano H. Chulada P. Spalding J. Lee C. Loftin C. Mahler J. Morham S. Langenbach R. Proc. Natl. Assn. Cancer Res. 1997; 38: 1727Google Scholar). These observations suggest that COX-2 has an important role in inflammation and carcinogenesis in the epidermis.Although many inflammatory skin diseases are associated with increased levels of IFN-γ and prostaglandin E2 (PGE2), the relationship between IFN-γ, prostaglandin synthesis, and inflammation in the epidermis is not well understood. In this study, we demonstrate that IFN-γ induces COX-2 expression and increases PGE2 production in normal human epidermal keratinocyte (NHEK) cells. We provide evidence indicating that this induction is mediated at least in part through activation of the epidermal growth factor receptor (EGFR; c-ErbB1) and is related to increased expression of growth factors such as TGFα. This induction of COX-2 is regulated in part at the transcriptional level and involves the CRE/ATF site in the proximal COX-2 promoter region. In addition, we demonstrate the importance of the activation of both the ERK and p38 MAPK signaling pathways in COX-2 induction. The stimulation of TGFα synthesis and possibly other cytokines by IFN-γ and the subsequent increase in PGE2 production are likely to be important signals involved in triggering the hyperproliferative transformation associated with many inflammatory diseases in the skin.DISCUSSIONIFN-γ has been reported to regulate the expression of COX-2 in several cell systems. In human bronchial epithelial cells and macrophages (42Asano K. Nakamura H. Lilly C.M. Klagsbrun M. Drazen J.M. J. Clin. Invest. 1997; 99: 1057-1063Crossref PubMed Scopus (45) Google Scholar, 62Riese J. Hoff T. Nordhoff A. DeWitt D.L. Resch K. Kaever V. J. Leukocyte Biol. 1994; 55: 476-482Crossref PubMed Scopus (78) Google Scholar), IFN-γ induces COX-2, while it has no effect in osteoblast and smooth muscle cells (41Pang L. Knox A.J. Br. J. Pharmacol. 1997; 121: 579-587Crossref PubMed Scopus (160) Google Scholar) and inhibits COX-2 expression in microglial cells (63Minghetti L. Polazzi E. Nicolini A. Creminon C. Levi G. J. Neurochem. 1996; 66: 1963-1970Crossref PubMed Scopus (110) Google Scholar). In this study, we demonstrate that in NHEK IFN-γ, treatment causes a dramatic induction in the expression of COX-2, while COX-1 expression is inhibited. The increase in the level of COX-2 protein by IFN-γ is probably responsible for the observed increase in PGE2 synthesis. We show that the induction of COX-2 by IFN-γ in NHEK is at least in part mediated through activation of the EGFR signaling pathway due to observed increased expression of TGFα and possibly other growth factors by IFN-γ. A similar mechanism has recently been reported for human bronchial epithelial cells (42Asano K. Nakamura H. Lilly C.M. Klagsbrun M. Drazen J.M. J. Clin. Invest. 1997; 99: 1057-1063Crossref PubMed Scopus (45) Google Scholar). The rapid increase in COX-2 expression by TGFα in NHEK (Fig. 7 C) as well as other cell types (40Mestre J.R. Subbaramaiah K. Sacks P.G. Schantz S.P. Tanabe T. Inoue H. Dannenberg A.J. Cancer Res. 1997; 57: 2890-2895PubMed Google Scholar, 42Asano K. Nakamura H. Lilly C.M. Klagsbrun M. Drazen J.M. J. Clin. Invest. 1997; 99: 1057-1063Crossref PubMed Scopus (45) Google Scholar, 45Loftin C.D. Eling T.E. Arch. Biochem. Biophys. 1996; 330: 419-429Crossref PubMed Scopus (21) Google Scholar,64Coffey R.J. Hawkey C.J. Damstrup L. Graves-Deal R. Daniel V.C. Dempsey P.J. Chinery R. Kirkland S.C. DuBois R.N. Jetton T.L. Morrow J.D. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 657-662Crossref PubMed Scopus (295) Google Scholar) and the temporal correlation between the induction of TGFα and COX are in agreement with such a mechanism. Observations showing that anti-EGFR antibodies and EGFR-selective kinase inhibitors almost totally block induction of COX-2 and PGE2 by IFN-γ suggest that activation of EGFR is a major signaling pathway involved in the up-regulation of COX-2 by IFN-γ. These findings are highly relevant to understanding the role that IFN-γ plays in inflammatory skin disease. Inflammatory processes in the skin, including psoriasis and dermatitis, are characterized by hyperplasia and the presence of high levels of IFN-γ as well as of TGFα and PGE2 (13Matue H. Cruz P.D. Bregstresser P.R. Takashima A. J. Invest. Dermatol. 1992; 99: 42S-45SAbstract Full Text PDF PubMed Scopus (85) Google Scholar,14Nickoloff B.J. Arch. Dermatol. 1991; 127: 871-884Crossref PubMed Scopus (318) Google Scholar, 20Elder J.T. Fisher G.J. Lindquist P.B. Bennett G.L. Pittelkow M.R. Coffey R.J. Ellingsworth L. Derynck R. Voorhees J.J. Science. 1989; 243: 811-814Crossref PubMed Scopus (501) Google Scholar, 27Carroll J.M. Crompton T. Seery J.P. Watt F.M. J. Invest. Dermatol. 1997; 108: 412-422Abstract Full Text PDF PubMed Scopus (139) Google Scholar, 46Maldve R.E. Fischer S.M. Mol. Carcinog. 1996; 17: 207-216Crossref PubMed Scopus (32) Google Scholar). Our findings provide a mechanism that links these three different effects in the skin and suggest that the induction of TGFα by IFN-γ and the resulting increase in the expression of COX-2 and production of PGE2 are an important part of hyperproliferative responses observed during inflammation in the skin and probably in other tissues as well.Previous studies have demonstrated that COX-2 expression can be regulated by transcriptional (40Mestre J.R. Subbaramaiah K. Sacks P.G. Schantz S.P. Tanabe T. Inoue H. Dannenberg A.J. Cancer Res. 1997; 57: 2890-2895PubMed Google Scholar, 41Pang L. Knox A.J. Br. J. Pharmacol. 1997; 121: 579-587Crossref PubMed Scopus (160) Google Scholar, 43Inoue H. Yokoyama C. Hara S. Tone Y. Tanabe T. J. Biol. Chem. 1995; 270: 24965-24971Abstract Full Text Full Text PDF PubMed Scopus (467) Google Scholar, 47Kutchera W. Jones D.A. Matsunami N. Groden J. McIntyre T.M. Zimmerman G.A. White R.L. Prescott S.M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 4816-4820Crossref PubMed Scopus (445) Google Scholar, 65Newton R. Kuitert L.M.E. Bergmann M. Adcock I.M. Barnes P.J. Biochem. Biophys. Res. Commun. 1997; 237: 28-32Crossref PubMed Scopus (358) Google Scholar, 66Xie W. Fletcher B.S. Andersen R.D. Herschman H.R. Mol. Cell. Biol. 1994; 14: 6531-6539Crossref PubMed Scopus (189) Google Scholar, 67Lukiw W.J. Pelaez R.P. Martinez J. Bazan N.G. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 3914-3919Crossref PubMed Scopus (72) Google Scholar, 68Crofford L.J. Tan B. McCarthy C.J. Hla T. Arthritis Rheum. 1997; 40: 226-236Crossref PubMed Scopus (247) Google Scholar, 69Xie W. Herschman H.R. J. Biol. Chem. 1996; 271: 31742-31748Abstract Full Text Full Text PDF PubMed Scopus (222) Google Scholar, 70Subbaramaiah K. Telang N. Ramonetti J.T. Araki R. DeVito B. Weksler B.B. Dannenberg A.J. Cancer Res. 1996; 56: 4424-4429PubMed Google Scholar, 71Subbaramaiah K. Chung W.J. Dannenberg A.J. J. Biol. Chem. 1998; 273: 32943-32949Abstract Full Text Full Text PDF PubMed Scopus (198) Google Scholar, 72Kim Y. Fischer S.M. J. Biol. Chem. 1998; 273: 27686-27694Abstract Full Text Full Text PDF PubMed Scopus (193) Google Scholar) as well as posttranscriptional (38Ristimäki A. Garfinkel S. Wessendorf J. Maciag T. Hla T. J. Biol. Chem. 1994; 269: 11769-11775Abstract Full Text PDF PubMed Google Scholar, 73Newton R. Seybold J. Liu S.L. Barnes P.J. Biochem. Biophys. Res. Commun. 1997; 234: 85-89Crossref PubMed Scopus (51) Google Scholar, 74Dean J.L.E. Brook M. Clark A.R. Saklatvala J. J. Biol. Chem. 1999; 274: 264-269Abstract Full Text Full Text PDF PubMed Scopus (461) Google Scholar) mechanisms. COX-2 mRNA is relatively unstable, and its stability is thought to be controlled by the multiple copies of the AUUUA instability motif in its 3′-untranslated region (73Newton R. Seybold J. Liu S.L. Barnes P.J. Biochem. Biophys. Res. Commun. 1997; 234: 85-89Crossref PubMed Scopus (51) Google Scholar, 75Adderley S.R. Fitzgerald D.J. J. Biol. Chem. 1999; 274: 5038-5046Abstract Full Text Full Text PDF PubMed Scopus (343) Google Scholar). In lung carcinoma A549 cells, the induction of COX-2 by IL-1β has been reported to occur at a posttranscriptional level (73Newton R. Seybold J. Liu S.L. Barnes P.J. Biochem. Biophys. Res. Commun. 1997; 234: 85-89Crossref PubMed Scopus (51) Google Scholar), and the increase in COX-2 mRNA levels by IL-1α in human endothelial cells appears also related to increased RNA stability (38Ristimäki A. Garfinkel S. Wessendorf J. Maciag T. Hla T. J. Biol. Chem. 1994; 269: 11769-11775Abstract Full Text PDF PubMed Google Scholar). In many systems, the induction of COX-2 has been demonstrated to be regulated at the transcriptional level. The high expression levels of COX-2 mRNA in colon and skin carcinomas and transformed mammary epithelial cells relative to normal cells (47Kutchera W. Jones D.A. Matsunami N. Groden J. McIntyre T.M. Zimmerman G.A. White R.L. Prescott S.M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 4816-4820Crossref PubMed Scopus (445) Google Scholar,70Subbaramaiah K. Telang N. Ramonetti J.T. Araki R. DeVito B. Weksler B.B. Dannenberg A.J. Cancer Res. 1996; 56: 4424-4429PubMed Google Scholar, 72Kim Y. Fischer S.M. J. Biol. Chem. 1998; 273: 27686-27694Abstract Full Text Full Text PDF PubMed Scopus (193) Google Scholar) as well as the induction of COX-2 by several growth factors, phorbol esters, and interleukins in several cell types has been reported to be controlled at the transcriptional level (40Mestre J.R. Subbaramaiah K. Sacks P.G. Schantz S.P. Tanabe T. Inoue H. Dannenberg A.J. Cancer Res. 1997; 57: 2890-2895PubMed Google Scholar, 43Inoue H. Yokoyama C. Hara S. Tone Y. Tanabe T. J. Biol. Chem. 1995; 270: 24965-24971Abstract Full Text Full Text PDF PubMed Scopus (467) Google Scholar,65Newton R. Kuitert L.M.E. Bergmann M. Adcock I.M. Barnes P.J. Biochem. Biophys. Res. Commun. 1997; 237: 28-32Crossref PubMed Scopus (358) Google Scholar, 66Xie W. Fletcher B.S. Andersen R.D. Herschman H.R. Mol. Cell. Biol. 1994; 14: 6531-6539Crossref PubMed Scopus (189) Google Scholar, 67Lukiw W.J. Pelaez R.P. Martinez J. Bazan N.G. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 3914-3919Crossref PubMed Scopus (72) Google Scholar, 68Crofford L.J. Tan B. McCarthy C.J. Hla T. Arthritis Rheum. 1997; 40: 226-236Crossref PubMed Scopus (247) Google Scholar, 69Xie W. Herschman H.R. J. Biol. Chem. 1996; 271: 31742-31748Abstract Full Text Full Text PDF PubMed Scopus (222) Google Scholar). In this study, we show that IFN-γ has little effect on the stability of COX-2 mRNA in NHEK cells. Nuclear run-off assays indicated that the induction of COX-2 expression by IFN-γ is related to an increase in the rate of transcription. The COX-2 promoter has been shown to contain a number of putative enhancer elements, including C/EBP, CRE/ATF, NF-κB, E-box, STAT3, and AP2 (43Inoue H. Yokoyama C. Hara S. Tone Y. Tanabe T. J. Biol. Chem. 1995; 270: 24965-24971Abstract Full Text Full Text PDF PubMed Scopus (467) Google Scholar, 66Xie W. Fletcher B.S. Andersen R.D. Herschman H.R. Mol. Cell. Biol. 1994; 14: 6531-6539Crossref PubMed Scopus (189) Google Scholar, 67Lukiw W.J. Pelaez R.P. Martinez J. Bazan N.G. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 3914-3919Crossref PubMed Scopus (72) Google Scholar, 72Kim Y. Fischer S.M. J. Biol. Chem. 1998; 273: 27686-27694Abstract Full Text Full Text PDF PubMed Scopus (193) Google Scholar, 75Adderley S.R. Fitzgerald D.J. J. Biol. Chem. 1999; 274: 5038-5046Abstract Full Text Full Text PDF PubMed Scopus (343) Google Scholar). The up-regulation of COX-2 by hypoxia is mediated through a NF-κB site (76Kosaka T. Miyata A. Ihara H. Hara S. Sugimoto T. Takeda O. Takahashi E. Tanabe T. Eur. J. Biochem. 1994; 221: 889-897Crossref PubMed Scopus (380) Google Scholar). The induction of COX-2 by phorbol esters and lipopolysaccharide in vascular endothelial cells occurs at the transcriptional level and involves regulation through the C/EBP and CRE/ATF sites in the proximal promoter region (43Inoue H. Yokoyama C. Hara S. Tone Y. Tanabe T. J. Biol. Chem. 1995; 270: 24965-24971Abstract Full Text Full Text PDF PubMed Scopus (467) Google Scholar). The v-Src induction of COX-2 in Balb/c 3T3 cells (66Xie W. Fletcher B.S. Andersen R.D. Herschman H.R. Mol. Cell. Biol. 1994; 14: 6531-6539Crossref PubMed Scopus (189) Google Scholar) and the increase in COX-2 expression by phorbol esters in oral carcinoma cells (40Mestre J.R. Subbaramaiah K. Sacks P.G. Schantz S.P. Tanabe T. Inoue H. Dannenberg A.J. Cancer Res. 1997; 57: 2890-2895PubMed Google Scholar) require the CRE/ATF site, while the transcriptional regulation of COX-2 in mouse skin carcinomas is dependent on the C/EBP and E-box sites (72Kim Y. Fischer S.M. J. Biol. Chem. 1998; 273: 27686-27694Abstract Full Text Full Text PDF PubMed Scopus (193) Google Scholar). Our results obtained by transient transfection assays using several reporter constructs, in which the reporter is under the control of various lengths of the COX-2 regulatory region, support the conclusion that TGFα regulates COX-2 gene expression at least in part at the transcriptional level. Deletion analysis of the −1432 bp regulatory region indicated that the −124 proximal promoter region containing the CRE/ATF/E-box element plays an important role in the transcriptional control by TGFα. This was confirmed by observations showing that mutations in the CRE/ATF/E-box element dramatically reduced promoter activity.Recently, it was reported that COX-2 expression can be regulated through different MAP kinase signaling pathways and that the particular signaling pathway involved is dependent on the type of inducer (59Guan Z. Buckman S.Y. Pentland A.P. Templeton D.J. Morrison A.R. J. Biol. Chem. 1998; 273: 12901-12908Abstract Full Text Full Text PDF PubMed Scopus (239) Google Scholar, 60Zakar T. Mijiovic J.E. Euster K.M. Bhardwaj D. Olson D.M. Biochim. Biophys. Acta. 1998; 1391: 37-51Crossref PubMed Scopus (31) Google Scholar,69Xie W. Herschman H.R. J. Biol. Chem. 1996; 271: 31742-31748Abstract Full Text Full Text PDF PubMed Scopus (222) Google Scholar, 71Subbaramaiah K. Chung W.J. Dannenberg A.J. J. Biol. Chem. 1998; 273: 32943-32949Abstract Full Text Full Text PDF PubMed Scopus (198) Google Scholar, 74Dean J.L.E. Brook M. Clark A.R. Saklatvala J. J. Biol. Chem. 1999; 274: 264-269Abstract Full Text Full Text PDF PubMed Scopus (461) Google Scholar, 77Schmedtje Jr., J.F. Ji Y.S. Liu W.L. DuBois R.N. Runge M.S. J. Biol. Chem. 1997; 272: 601-608Abstract Full Text Full Text PDF PubMed Scopus (634) Google Scholar). The induction of COX-2 by PDGF has been demonstrated to require activation of the ERK signaling pathway (69Xie W. Herschman H.R. J. Biol. Chem. 1996; 271: 31742-31748Abstract Full Text Full Text PDF PubMed Scopus (222) Google Scholar), while constitutively active MEKK1 has been shown to induce COX-2 expression by activating the SEK1/MKK4-p38 kinase pathway (59Guan Z. Buckman S.Y. Pentland A.P. Templeton D.J. Morrison A.R. J. Biol. Chem. 1998; 273: 12901-12908Abstract Full Text Full Text PDF PubMed Scopus (239) Google Scholar). EGF/TGFα has been reported to activate several signaling pathways including STAT and MAPKs (61Lange C.A. Richer J.K. Shen T. Horwitz K.B. J. Biol. Chem. 1998; 273: 31308-31316Abstract Full Text Full Text PDF PubMed Scopus (167) Google Scholar, 78David M. Wong L. Flavell R. Thompson S.A. Well
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