Inhibition of Helicobacter pylori-induced nuclear factor-kappa B activation and interleukin-8 gene expression by ecabet sodium in gastric epithelial cells.

Abstract

Helicobacter pylori stimulates nuclear factor-kappa B (NF-kappa B) activation and chemokine interleukin-8 (IL-8) expression in gastric epithelial cells. Ecabet sodium (ecabet), a locally acting antiulcer drug, is known to have anti-H. pylori activity. However, there is little understanding of how ecabet induces anti-inflammatory activity in gastric epithelial cells infected with H. pylori. The aim of this study was to investigate the effects of ecabet on IL-8 gene expression and NF-kappa B activation in human gastric epithelial cells infected with H. pylori. After Hs746T, MKN-45, or SNU-5 gastric epithelial cell lines had been infected with cagA+cytotoxin+H. pylori in the presence of ecabet, IL-8 mRNA expression was assessed by quantitative reverse transcription-polymerase chain reaction, and IL-8 secretion was measured by enzyme-linked immunosorbent assay. NF-kappa B and inhibitory kappa B-alpha (I kappa B alpha) signals were assayed by electrophoretic mobility shift assay and Western blot, respectively. The activation of NF-kappa B and IL-8 reporter genes was determined by luciferase assay. Ecabet showed no antimicrobial activiy against Gram-positive or -negative bacteria. However, ecabet inhibited transcription of the IL-8 gene and secretion of IL-8 by gastric epithelial cells infected with H. pylori at a concentration of 5 micro g/ml. Moreover, ecabet inhibited the activation of NF- kappa B and the degradation of I kappa B alpha in gastric epithelial cells in response to H. pylori infection. In addition, the NF-kappa B signal inhibited by ecabet was comprised predominantly of heterodimers of p65/p50. Ecabet inhibited H. pylori-induced IL-8 gene transcription and secretion by suppressing the NF-kappa B signal. This inhibition might be one pathway by which ecabet exerts its anti-inflammatory effect on H. pylori-induced gastric inflammation.