Celecoxib Inhibits Apurinic/Apyrimidinic Endonuclease-1 Expression and Prevents Gastric Cancer in Helicobacter pylori-Infected Mongolian Gerbils

Abstract

Background and Aims: The aim of this study was to see whether administration of celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, could prevent the development of gastric cancer via inhibition of apurinic/apyrimidinic endonuclease-1 (APE-1) expression induced by Helicobacter pylori infection. Methods: 70 Mongolian gerbils were divided into 6 groups. Group 1 gerbils served as controls (n = 6). Ten gerbils were given N-methyl-N-nitrosourea (MNU), 30 ppm, 5 times biweekly (group 2). Short-term H. pylori infection was induced in 6 gerbils which were sacrificed 8 weeks after H. pylori infection (group 3). Long-term H. pylori infection was induced in 6 other gerbils which were sacrificed 44 weeks after H. pylori infection (group 4). Twenty gerbils were given MNU pretreatment 5 times biweekly and long-term H. pylori infection (group 5). In addition, after H. pylori inoculation, group 6 gerbils also received celecoxib with their diet for 26 weeks. APE-1 expression alone or with COX-2 in gastric tissues was evaluated by Western blot and immunohistological analysis. Myeloperoxidase (MPO) activity and thiobarbituric-acid-reactive substance (TBARS) levels were also evaluated. Results: APE-1 was localized in gastric epithelial cells and mesenchymal cells including macrophages in H. pylori-infected gerbils. The numbers of APE-1-positive cells in group 4 and 5 were significantly increased compared to those of group 3. Celecoxib treatment significantly reduced MPO activity, TBARS levels and the incidence of gastric cancer. APE-1 and IκBα phosphorylation levels were significantly increased in MNU-pretreated H. pylori-infected gerbils compared to those in MNU-only gerbils. Celecoxib significantly reduced APE-1 and IκBα phosphorylation levels in MNU-pretreated H. pylori-infected gerbils. COX-2 and APE-1 were coexpressed in the macrophages of H. pylori-infected gerbils. Conclusion: Celecoxib prevented gastric cancer in MNU-pretreated H. pylori-infected gerbils with a reduction in APE-1 expression thereby suggesting the implication of APE-1 in gastric carcinogenesis in this model.