RESUMEN
Objective To investigate the effects of Helicobacter priori (H.prlori) strains from the patient with gastric cancer on the expression of DNA mismatch repair (MMR) genes in AGS cells in vitro. Methods AGS cells were co-cultured with ten strains of H.prlori from five patients with gastric cancer and five patients with gastritis respectively.The expressions of DNA MMR genes (hMSH2 and hMLH1) in mRNA and protein levels were determined by RT-PCR and Western blot.The enteropathogenic E.coli served as a bacterial control.Results E.coli and H.priori strains from gastritis have no effects on the expression of hMSH2 and hMLH1 in both protein and mRNA levels on the whole,while all the H.prlori strains from gastric cancer reduced expression levels of hMSH2 and hMLH1.Conclusions There are different effects between H. prlori strains from gastric cancer and those from gastritis on DNA MMR in AGS cell line,indicating that infec- tion of some H.prlori strains might lead to the inhibition of DNA MMR,and that in turns increases the risk of gastric carcinogenesis during chronic H.prlori infection.