Effect of Helicobacter pylori infection on Fas-associated factor 1 expression in human carcinoma cells and human gastric epithelial cells

Abstract

Objective To investigate the relationship between the Fas-associated factor 1 (FAF1)expression with Helicobacter pylori (Hp) infection and carcinogenesis of gastric cancer.Methods 8 × 105 cells of human gastric carcinoma cells (HGC-27) and human gastric epithelial cells (GES-1) were co-cultured with Hp standard strain NCTC11637 for 24 h,and the cells were divided by cell/bacterial ratio into three groups:control group,1∶100 and 1∶200 co-culture groups.Each experiment was conducted three times and each sample was assayed in triplicate.Thiazolyl blue (MTT) assay was used to determine the proliferation in 490 nm,flow cytometry to determine the apoptosis of 1 × 104 cells per group,and real-time fluorescent quantitative reverse transcriptase polymerase chain reaction (FQ-PCR) to detect the relative expression of FAF1 mRNA.The sequence length was 164 bp.Results After co-culture with Hp,proliferation of cells was decreased and apoptosis was increased.As compare with respective control group,the relative expression of FAF1 mRNA in 1 ∶ 100 co-culture group and 1 ∶ 200 co-culture group in HGC-27 cells was significantly decreased (0.67 ± 0.20 vs.0.99 ± 0.27,F =11.51,P ＜ 0.05 ; 0.44 ± 0.30 vs.0.99 ±0.27,F =11.5 1,P ＜ 0.01).The relative expression of FAF1 mRNA in 1∶100 co-culture group in GES-1 cells was significantly increased (1.61 ± 0.77 vs.0.99 ± 0.41,F =14.45,P ＜ 0.05),and that in 1∶200 co-culture group in GES-1 cells was significantly decreased (0.36 ±0.22 vs.0.99 ±0.41,F =14.45,P ＜0.05).As compared with control group,1∶100 and 1∶200 co-culture groups of GES-1 cells,the expression levels of FAF1 mRNA in each corresponding group of HGC-27 cells were significantly decreased (0.33±0.16vs.0.99±0.41,t=4.74,P＜0.01; 0.17±0.12 vs.1.08±±0.53,t=5.28,P＜0.01;0.39±0.24 vs.0.98 ±0.23,t=5.67,P＜0.01).Conclusion Hp infection can down-regulate the expression of FAF1 gene,leading to gastric cell proliferation and apoptosis imbalance,then inducing the carcinogenesis of gastric cancer. Key words: Stomach neoplasms; Fas-associated factor 1 ; Apoptosis; Helicobacter pylori