OBJECTIVE

To investigate whether, or how, DA-9601, which is a new gastroprotective agent, inhibits TNF-alpha-induced inflammatory signals in gastric epithelial AGS cells.

METHODS

Cell viability was determined by MTT assay. IL-8 and CCL20 promoter activities were determined by a luciferase reporter gene assay. NF-kappaB-dependent transcriptional activity was determined by I-kappaB alpha degradation, NF-kappaB p65 nuclear translocation and a luciferase activity assay. IL-8 and CCL20 gene expression and protein secretion were determined by RT-PCR and an enzyme-linked immunosorbent assay (ELISA). Total and phosphorylated forms of mitogen-activated protein kinases (MAPKs) were determined by Western blot.

RESULTS

Treatment of AGS cells with DA-9601 reduced TNF-alpha-induced IL-8 and CCL20 promoter activities, as well as their gene expression and protein release. TNF-alpha also induced NF-kappaB-dependent transcriptional activity in AGS cells. In contrast, in cells treated with DA-9601, TNF-alpha-induced NF-kappaB activity was significantly blocked. Although all three MAP kinase family members were phosphorylated in response to TNF-alpha, a selective inhibitor of p38 kinase SB203580 only could inhibit both NF-kappaB-dependent transcriptional activity and IL-8 and CCL20 production, suggesting a potential link between p38 kinase and NF-kappaB-dependent pathways in AGS cells. Interestingly, DA-9601 also selectively inhibited p38 kinase phosphorylation induced by TNF-alpha.

CONCLUSIONS

DA-9601 blocked TNF-alpha-mediated inflammatory signals by potentially modulating the p38 kinase pathway and/or a signal leading to NF-kappaB-dependent pathways in gastric epithelial cells.