RRC ID 39572
Author Maeda S, Yoshida H, Ogura K, Mitsuno Y, Hirata Y, Yamaji Y, Akanuma M, Shiratori Y, Omata M.
Title H. pylori activates NF-kappaB through a signaling pathway involving IkappaB kinases, NF-kappaB-inducing kinase, TRAF2, and TRAF6 in gastric cancer cells.
Journal Gastroenterology
Abstract BACKGROUND & AIMS:H. pylori infection on gastric epithelial cells has been shown to induce NF-kappaB activation, but the mechanism of intracellular signal conduction that leads to NF-kappaB activation is not clear. The aim of this study was to analyze the molecular mechanism responsible for H. pylori-mediated NF-kappaB activation on gastric cancer cells.
METHODS:NF-kappaB activation by H. pylori was tested by using luciferase reporter assay. IkappaBalpha degradation by H. pylori infection was assessed by immunoblotting. IKKalpha and IKKbeta activation was analyzed by kinase assay. In transfection experiments, effects of dominant negative IkappaBalpha, IKKalpha, IKKbeta, NF-kappaB-inducing kinase (NIK), TRAF2, and TRAF6 mutants were investigated. The effects of an IKKbeta-specific inhibitor, aspirin, on NF-kappaB activation and IL-8 secretion were also analyzed.
RESULTS:H. pylori promotes degradation of IkappaBalpha, a cytoplasmic inhibitor of NF-kappaB. In kinase assay, H. pylori induced IKKalpha and IKKbeta catalytic activity in gastric cancer cells. Transfection of kinase-deficient mutant of either IKK inhibited H. pylori-mediated NF-kappaB activation dose-dependently. Aspirin inhibited both NF-kappaB activation and IL-8 secretion induced by H. pylori. NF-kappaB activation was also inhibited by transfection of kinase-deficient NIK or a dominant negative mutant of upstream adapter protein TRAF2 or TRAF6.
CONCLUSIONS:H. pylori induces NF-kappaB activation through an intracellular signaling pathway that involves IKKalpha, IKKbeta, NIK, TRAF2, and TRAF6.
Volume 119(1)
Pages 97-108
Published 2000-7
DOI 10.1053/gast.2000.8540
PII S001650850042528X
PMID 10889159
MeSH Aspirin / pharmacology Genes, Dominant Helicobacter pylori / physiology* Humans I-kappa B Kinase I-kappa B Proteins / metabolism I-kappa B Proteins / physiology Interleukin-8 / metabolism Mutation / physiology NF-kappa B / antagonists & inhibitors NF-kappa B / physiology* Phosphorylation Phosphotransferases / deficiency Protein-Serine-Threonine Kinases / physiology Proteins / genetics Proteins / physiology Signal Transduction / physiology* Stomach Neoplasms / microbiology Stomach Neoplasms / pathology Stomach Neoplasms / physiopathology* TNF Receptor-Associated Factor 2 TNF Receptor-Associated Factor 6 Tumor Cells, Cultured
IF 19.809
Times Cited 126
Human and Animal Cells