Apoptosis of human gastric carcinoma AGS cells induced by cecropinXJ / 中国药理学通报

ABSTRACT

Aim To investigate the apoptosis of human gastric carcinoma AGS cells induced by cecropinXJ. Methods Human gastric carcinoma AGS cells and human normal epithelial cells GES-1 were co-cultured with different concentrations of cecropinXJ ranging from 0. 01 to 1 000 mg·L-1 for 24 h. MTT assay was used to observe the effects of cecropinXJ on the proliferation of AGS cells and GES-1 cells. The ultrastructural changes of the AGS cells were observed by transmission electron microscopy. Hoechst staining was used to de-tect cell apoptosis. The changes of intracellular reac-tive oxygen species ( ROS) and mitochondrial potential were analysed by flow cytometery. The expression of Bax, Bcl-2, caspase-3 and cytochrome C in mRNA level was investigated by qRT-PCR. Western blot was used to determine the protein expression of Bax, Bcl-2, caspase-3 and cytochrome C. Results CecropinXJ significantly suppressed the proliferation of AGS cells in vitro (P<0. 05) in a dose-dependent manner, IC50 =61. 19 mg·L-1 , but had no inhibitive effects on the proliferation of GES-1 cells. After treatment for 24 h, cecropinXJ induced AGS cells nuclear condensation, and increased ROS production, disrupted mitochondri-al integrity. The results of qRT-PCR and Western blot demonstrated cecropinXJ could up-regulate the expres-sion of Bax and down-regulate the expression of Bcl-2 , promote the release of cytochrome C and activate caspase-3. Meanwhile, cecropinXJ promoted caspase-3 activity in a dose-dependent manner, and cell death ratio of AGS cells induced by cecropinXJ was signifi-cantly reduced by caspase-3 and caspase-9 specific in-hibitors treatment. Conclusion CecropinXJ can in-duce apoptosis of AGS cells by downregulating Bcl-2 , upregulating Bax and activating caspase-3 , which may be one of its anti-tumor mechanisms.