Overexpressed
gastrin is reported to promote
oncogenesis and development of
gastric cancer by inhibiting apoptosis of
cancer cells; however, the underlying mechanism remains unclear. Our study is aimed at revealing the mechanism underlying the effect of
gastrin on apoptosis of
gastric cancer cells.
Gastrin-interfering cell line was constructed by stably transfecting
gastrin-specific pshRNA plasmid to
gastric cancer cell line BGC-823. Then, differentially expressed
proteins between untreated BGC-823 and
gastrin-interfering BGC-823 cell lines were detected by the iTRAQ technique. GO and KEGG analysis was used to analyze the differentially expressed genes that code these differentially expressed
proteins. The
Annexin V-FITC staining assay was used to detect
gastric cancer cell apoptosis. The
DCFH-DA fluorescent probe staining assay was used to measure intracellular ROS. Mitochondrial membrane potential was detected by flow cytometry. Western blot was used to analyze the mitochondria respiratory chain
proteins and apoptosis-related
proteins. A total of 107 differentially expressed
proteins were identified by iTRAQ. GO and KEGG analysis showed that
proteins coded by the corresponding differentially expressed genes were mainly enriched in the mitochondrial oxidative respiratory chain, and the expression of three
proteins (COX17, COX5B, ATP5J) was upregulated. The three
proteins with higher scores were verified by Western blot. The apoptosis rate of the
gastrin knockdown
cancer cell was significantly increased; meanwhile,
gastrin knockdown leads to increase of membrane potential and decrease of intracellular ROS production. Additionally, Bax was significantly increased, whereas NF-κB-p65 and Bcl-2 were downregulated after knockdown of
gastrin. Concomitantly, pretreatment with NAC reversed the effect of
gastrin on the Bax and Bcl-2 expression.
Gastrin promotes the production of ROS from mitochondria, activates NF-κB, and inhibits apoptosis via modulating the expression level of Bcl-2 and Bax.