Activation of beta-catenin by carcinogenic Helicobacter pylori.

Franco AT, Israel DA, Washington MK, Krishna U, Fox JG, Rogers AB, Neish AS, Collier-Hyams L, Perez-Perez GI, Hatakeyama M, Whitehead R, Gaus K, O'Brien DP, Romero-Gallo J, Peek RM
Proc Natl Acad Sci U S A. 2005 102 (30): 10646-51

PMID: 16027366 · PMCID: PMC1180811 · DOI:10.1073/pnas.0504927102

Persistent gastritis induced by Helicobacter pylori is the strongest known risk factor for adenocarcinoma of the distal stomach, yet only a fraction of colonized persons ever develop gastric cancer. The H. pylori cytotoxin-associated gene (cag) pathogenicity island encodes a type IV secretion system that delivers the bacterial effector CagA into host cells after bacterial attachment, and cag+ strains augment gastric cancer risk. A host effector that is aberrantly activated in gastric cancer precursor lesions is beta-catenin, and activation of beta-catenin leads to targeted transcriptional up-regulation of genes implicated in carcinogenesis. We report that in vivo adaptation endowed an H. pylori strain with the ability to rapidly and reproducibly induce gastric dysplasia and adenocarcinoma in a rodent model of gastritis. Compared with its parental noncarcinogenic isolate, the oncogenic H. pylori strain selectively activates beta-catenin in model gastric epithelia, which is dependent on translocation of CagA into host epithelial cells. Beta-catenin nuclear accumulation is increased in gastric epithelium harvested from gerbils infected with the H. pylori carcinogenic strain as well as from persons carrying cag+ vs. cag- strains or uninfected persons. These results indicate that H. pylori-induced dysregulation of beta-catenin-dependent pathways may explain in part the augmentation in the risk of gastric cancer conferred by this pathogen.

MeSH Terms (17)

Adenocarcinoma Animals Antigens, Bacterial Bacterial Proteins beta Catenin Blotting, Western Enzyme-Linked Immunosorbent Assay Fluorescent Antibody Technique Gene Expression Regulation, Neoplastic Gerbillinae Helicobacter pylori Humans Immunohistochemistry Luciferases Male Protein Transport Stomach Neoplasms

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