Helicobacter pylori CagA and Gastric Cancer: A Paradigm for Hit-and-Run Carcinogenesis

• Published in: Cell host & microbe 2014-03, Vol.15 (3), p.306-316
• Main Author: Hatakeyama, Masanori
• Format: Article
• Language: English
• Subjects: Antigens, Bacterial - metabolism; Bacterial Proteins - metabolism; Carcinogens - metabolism; Helicobacter Infections - complications; Helicobacter Infections - pathology; Helicobacter pylori - physiology; Humans; Stomach Neoplasms - microbiology; Stomach Neoplasms - pathology; Virulence Factors - metabolism
• ISSN: 1931-3128; 1934-6069
• DOI: 10.1016/j.chom.2014.02.008

Helicobacter pylori is a gastric bacterial pathogen that is etiologically linked to human gastric cancer. The cytotoxin-associated gene A (CagA) protein of H. pylori, which is delivered into gastric epithelial cells via bacterial type IV secretion, is an oncoprotein that can induce malignant neoplasms in mammals. Upon delivery, CagA perturbs multiple host signaling pathways by acting as an extrinsic scaffold or hub protein. On one hand, signals aberrantly raised by CagA are integrated into a direct oncogenic insult, whereas on the other hand, they engender genetic instability. Despite its decisive role in the development of gastric cancer, CagA is not required for the maintenance of a neoplastic phenotype in established cancer cells. Therefore, CagA-conducted gastric carcinogenesis progresses through a hit-and-run mechanism in which pro-oncogenic actions of CagA are successively taken over by a series of genetic and/or epigenetic alterations compiled in cancer-predisposing cells during long-standing infection with cagA-positive H. pylori. Hatakeyama reviews the mechanisms by which the Helicobacter pylori oncoprotein CagA perturbs host cell pathways and contributes to genetic instability, leading to the development of gastric carcinoma.