Induction Of Apoptosis And Influence On STAT3 And VEGF Expression In Gastric Cancer Cell AGS By Arsenic Trioxide

Objective: To study the effects of arsenic trioxide (As₂O₃) on inducing apoptosis and investigate the expression change of STAT3 and VEGF in gastric carcinoma cell line AGS in vitro. Methods :The cell activity and morphologic changes were studied after being treated with arsenic trioxide (As₂O₃) at the concentration of 1,5,10μmol/L, respectively, for 24,48,72 hours. The effect of As₂O₃ on the proliferation of AGS cells was measured with MTT essay. As Soon as the cells were harvested at 24,48,72hours, Changes of apoptosis and cell cycle distribution were analyzed with flow cytometry. The characteristics of apoptosis were further examined by TUNEL. The expression of Stat3 and VEGF were determined by FCM and immunohistochemistry. VEGF level was measured with ELISA in the different concentration and cultural time of the cultural supernatants.P-53,bcl-2,VEGF,Stat3 and p21 mRNA expressions were detected by using RT-PCR. Western blotting were used to detected the expression of p—Stat3 protein. Results: MTT results showed that cell proliferation was remarkably inhibited. The inhibition rate of 10μmol/ L As₂O₃ on AGS was almost 53.49 % in 72 hours. A typical sub-diploid peak before G0/G1 phase was observed by flow cytometry. The apoptotic index was 2.38% -7.82 % by FCM assay. The effect of As₂O₃ on AGS showed a remarkable cell cycle specificity, which indicates that As₂O₃ mainly acts on G2/M phase. TUNEL detection analysis revealed DNA fragmentation. As₂O₃ treated cells presented some typical features of apoptosis such as in tact cell membrane, chromate in condensation, nucleic fragmentation and apoptotic body formation. The expression of STAT3,P-STAT3 and VEGF was down-regulated after treatment with As₂O₃. Conclusion: As₂O₃ could significantly inhibit the proliferation of AGS cells and the inhibitory effect was dose-and-time dependent. Also the induction of apoptosis is a very important mechanism of As₂O₃ to treat gastric carcinoma AGS cells via down-regulate the expression of Stat3. And As₂O₃ prevents processes of gastric carcinoma through down-regulating expression of VEGF. Elevated activity of P-Stat3 can be found in different stages of human gastric cancer cell line AGS.JAK/ STAT signal transduction pathway may play an important role in the treatment of human gastric cancer by As₂O₃.It has potential value in the treatment of gastric cancer, and isworth further studies.