RESUMO
AIM:To investigate the effect of dihydroartemisinin ( DHA) adjuvant treatment on enhancing the antitumor effect of 5-fluorouracil (5-FU) against gastric cancer .METHODS:The gastric cancer BGC-823 cells were di-vided into control group , DHA group, 5-FU group, 5-FU+DHA group and 5-FU+DHA+SIRT1 plasmid group.The via-bility of BGC-823 cells treated with DHA and 5-FU was measured by MTT assay .The expression of SIRT1 and NADPH ox-idase, activation of caspase-9 and caspase-3, and phosphorylation of ASK1 and JNK in the BGC-823 cells treated with DHA and 5-FU were determined by Western blot .The production of ROS and the apoptosis of the BGC-823 cells treated with DHA and 5-FU were analyzed by flow cytometry .RESULTS:Dihydroartemisinin significantly inhibited the expression of SIRT1 and increased NADPH oxidase protein level (P<0.05).DHA increased the sensitivity of BGC-823 cells to 5-FU, thus decreasing the IC50 of 5-FU to the gastric cancer cells.However, transfection with SIRT1 plasmid decreased the cytotoxicity of DHA and 5-FU co-treatment to the BGC-823 cells.DHA promoted the production of ROS and phosphoryla-tion of ASK1 and JNK induced by 5-FU in the BGC-823 cells ( P<0.05 ) .However , ROS scavenger N-acetylcysteine ( NAC) or JNK specific inhibitor SP600125 inhibited the cell death and activation of caspase-9 and caspase-3 induced by DHA and 5-FU co-treatment (P<0.05).In addition, NAC significantly inhibited the phosphorylation of JNK in the BGC-823 cells co-treated with DHA and 5-FU.However, treatment with SP600125 did not influence the ROS production in the BGC-823 cells, indicating that JNK was the downstream target of ROS pathway .CONCLUSION: Combination of DHA with 5-FU induces caspase-dependent apoptosis in gastric cancer cells through the SIRT 1/NADPH oxidase/ROS/JNK sig-naling pathway .