miR-21 inhibits the effects of cyclooxygenase-2 inhibitor NS398 on apoptosis and invasion in gastric cancer cells

Abstract

Huanqing Li,1 Jian Cheng,2 Yuqing Mao,1 Miao Jiang,1 Xiaoming Fan1,2 1Department of Gastroenterology, Jinshan Hospital, 2Department of Internal Medicine, Shanghai Medical College, Fudan University, Shanghai, People’s Republic of China Objective: To investigate the role of miR-21 in cyclooxygenase-2 inhibitor NS398-induced apoptosis and invasion in gastric cancer (GC) cells. Methods: AGS cells were treated with NS398 and transfected with miR-21. Quantitative real-time polymerase chain reaction was used to measure miR-21 mRNA expression. Apoptotic cells were assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling and flow cytometric analysis. The protein expression of cleaved caspase-3, Bcl-2, Bax, Bak, and PTEN was detected by Western blot. The capacities for invasion and migration were measured by transwell and wound-healing assays, respectively. Results: Treatment of AGS cells with NS398 induced apoptosis in a dose-dependent manner accompanied by significant downregulation of miR-21 mRNA expression. Upregulation of miR-21 expression by transfection of miR-21 mimics into AGS cells blocked NS398-induced apoptosis. Treatment of AGS cells with NS398 induced changes in Bcl-2 protein family members, showing an increase in the protein expression of Bax, Bak, and PTEN, with a concomitant decrease in the protein expression of Bcl-2. In cells transfected with miR-21 mimics, these changes were reversed. The decrease in cellular invasiveness and migration induced by NS398 was blocked by upregulation of miR-21. Conclusion: miR-21 mediates anticancer effects of NS398 in GC cells by regulating apoptosis-related proteins. miR-21 is one of the molecular targets of this specific cyclooxygenase-2 inhibitor in the prevention and treatment of GC. Keywords: gastric cancer cells, apoptosis, stomach neoplasms, cyclooxygenase 2 inhibitors