Study Of Gastric Epithelial Cells Infected By Helicobacter Pylori On Expression Of Reck And Its Modulating Mechanism

Objective: RECK (reversion inducing cysteine-rich protein with kazal motifs) is a new type of matrix metallo-proteinase inhibitor This study was carried out to investigate the methylation and mRNA level of RECK gene induced by Helicobacter pylori in gastric epithelial cell, study the effect of NF-κB on the abnormal RECK expression, and elucidate the possible mechanism of H. pylori-induced gastric cancer.Methods: The cultured human gastric epithelial cell line GES-1 was infected by H. pylori with a MOI of 0.5:1 for 0~144h. After infection, cell DNA was abstracted, and the methylation in RECK promoter region was acessessed by methylation-specific PCR (MSP). The mRNA level of RECK was detected by RT-PCR. Total protein and nucleoprotein were extracted, and the nuclear translocation of p65 was detected by Western blot for study activation of NF-κB. In order to elucidate the effect of NF-κB on the abnormal expression of RECK mRNA, a specific inhibitor, pyrrolidine dithiocarbamate(PDTC) was used.Result1. No specific MSP band was detected when GES-1 had infected by H. pylori for 72h except for a weak non-methylation band. When the cells had been infected for 96h, a methylation band was appeared, and the peak arrived at 144h.2. RT-PCR shows the mRNA leveal of RECK decreased when GES-1 had been infected for 144h, but there was no marked change at 0~72h.3. The p65 translocated to the nucleus when GES-1 cells had been infected for 24h, and lasted to 72h. When infected for 96h, the activity of NF-κB was increased.4. PDTC could increase the mRNA level of RECK when incubated for 96~144h.ConclusionH. pylori could induced RECK promoter region methylation in GES-1 cells and decrease the mRNA level of RECK in GES-1 cells, thus cause the attenuated inactivation of MMP, which may be one of the pathogenesis of H. pylori-induced gastric cancer.