title: Nonsteroidal anti-inflammatory drug-activated gene-1 expression inhibits urethane-induced pulmonary tumorigenesis in transgenic mice.
abstract: The expression of nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1) inhibits gastrointestinal tumorigenesis in NAG-1 transgenic mice (C57/BL6 background). In the present study, we investigated whether the NAG-1 protein would alter urethane-induced pulmonary lesions in NAG-1 transgenic mice on an FVB background (NAG-1(Tg+/FVB)). NAG-1(Tg+/FVB) mice had both decreased number and size of urethane-induced tumors, compared with control littermates (NAG-1(Tg+/FVB) = 16 +/- 4 per mouse versus control = 20 +/- 7 per mouse, P < 0.05). Urethane-induced pulmonary adenomas and adenocarcinomas were observed in control mice; however, only pulmonary adenomas were observed in NAG-1(Tg+/FVB) mice. Urethane-induced tumors from control littermates and NAG-1(Tg+/FVB) mice highly expressed proteins in the arachidonic acid pathway (cyclooxygenases 1/2, prostaglandin E synthase, and prostaglandin E(2) receptor) and highly activated several kinases (phospho-Raf-1 and phosphorylated extracellular signal-regulated kinase 1/2). However, only urethane-induced p38 mitogen-activated protein kinase (MAPK) phosphorylation was decreased in NAG-1(Tg+/FVB) mice. Furthermore, significantly increased apoptosis in tumors of NAG-1(Tg+/FVB) mice compared with control mice was observed as assessed by caspase-3/7 activity. In addition, fewer inflammatory cells were observed in the lung tissue isolated from urethane-treated NAG-1(Tg+/FVB) mice compared with control mice. These results paralleled in vitro assays using human A549 pulmonary carcinoma cells. Less phosphorylated p38 MAPK was observed in cells overexpressing NAG-1 compared with control cells. Overall, our study revealed for the first time that the NAG-1 protein inhibits urethane-induced tumor formation, probably mediated by the p38 MAPK pathway, and is a possible new target for lung cancer chemoprevention.
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Cekanova
authors.forename: Seong-Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Robert L
authors.initials: RL
authors.lastname: Donnell
authors.forename: Mugdha
authors.initials: M
authors.lastname: Sukhthankar
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Eling
authors.forename: Susan M
authors.initials: SM
authors.lastname: Fischer
authors.forename: Seung Joon
authors.initials: SJ
authors.lastname: Baek
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western; D002273:Carcinogens / Q000633:toxicity*; D045744:Cell Line, Tumor; D055436:Growth Differentiation Factor 15 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008175:Lung Neoplasms / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D014520:Urethane / Q000633:toxicity*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D002273:Carcinogens; D055436:Growth Differentiation Factor 15; D014520:Urethane; D048051:p38 Mitogen-Activated Protein Kinases