Objective To observed the effect of IL-1β on expression of caudal-related homeobox gene 1 (CDX1) mRNA and mucoprotein 2 (MUC2) mRNA in cultured human gastric epithelial cells GES-1, and to investigate the underlying signal transduction pathways. Methods ①GES-1 cell was activated with IL-1β of different concentrations and time, the expression levels of CDX1 mRNA and MUC2 mRNA were detected by using real-time PCR. ②GES-1 cell was pretreated with PDTC, a NF-κB inhibitor, for 1 h prior to the addition of IL-1β, then the expressions of CDX1 mRNA and MUC2 mRNA were measured. Results Both CDX1 mRNA and MUC2 mRNA were not examined in GES-1 cell under normal culture conditions. But they could be induced by IL-1β with a dose-dependent manner in a concentration range (P＜0.05); 8 h after treatment with IL-1β, the peak values of the expression levels of CDX1 mRNA and MUC2 mRNA were reached (P＜0.05), then declined gradually. When pre-incubated with NF-κB inhibitor PDTC, the expression levels of CDX1 mRNA and MUC2 mRNA were significantly decreased (P＜0.05). Conclusion IL-1β significantly induces the expressions of CDX1 mRNA and MUC2 mRNA in cultured human gastric epithelial cell GES-1 through the NF-κB signal pathway, which indicates that IL-1β plays a role in the process of intestinal metaplasia.
Objective To study the effect of knockdown of signal transducer and activator of transcription 3 (STAT3) expression by short hairpin RNA (shRNA) on proliferation, apoptosis and invasion of human gastric cancer cell line MKN-45 in vitro . Methods Specific shRNA plasmids to STAT3 were constructed, and then transfected into MKN-45 cells by lipofectamine methods. Cells were divided into three groups: control group, psiRNA-H1 transfected group as negative group and psiRNA-H1/STAT3 transfected group. Semi-quantitative RT-PCR and Western blotting were used to detect the expression of STAT3 mRNA and protein, respectively. Proliferation and apoptosis of the transfected cells were observed by methyl thiazolyl tetrazolium (MTT) method and flow cytometry (FCM), respectively. The invasion of the transfected MKN-45 cells was measured by Boyden chamber. Results Compared with the negative control cells, semi-quantitative RT-PCR and Western blotting showed that the expressions of STAT3 mRNA and protein were down-regulated in the psiRNA-H1/STAT3 transfected group ( P ＜ 0.05) . The subcloned recombinant plasmid expressing shRNA effectively inhibited MKN-45 cell growth and proliferation while empty plasmid had no such specific effect. Cell apoptosis rate increased significantly in psiRNA-H1/STAT3 transfected group （ P ＜ 0.01）, and the invasion of MKN-45 cells was efficiently inhabited in psiRNA-H1/STAT3 transfected group as compared with control group and psiRNA-H1 transfected group( P ＜ 0.01).Conclusion Recombinant plasmid psiRNA-H1/STAT3 shRNA significantly inhibits the proliferation and invasion of MKN-45 cells and promotes their apoptosis.