Molecular characterization of H. pylori-infected cells associated with the development of gastric cancer

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K08349
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental and hygienic pharmacy
• Research Institution: Keio University
• Principal Investigator: Tsugawa Hitoshi 慶應義塾大学, 医学部(信濃町), 講師 (30468483)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 癌幹細胞 / オートファジー / 胃癌 / ピロリ菌 / CAPZA1 / CD44

Outline of Final Research Achievements

Helicobacter pylori-derived CagA plays a role as an oncogenic driver in gastric epithelial cells. However, upon delivery into gastric epithelial cells, CagA is usually degraded by autophagy. We report that enhancement of lysosome associated membrane protein 1 (LAMP1) expression is necessary for autophagolysosome formation. In contrast, CAPZA1 inhibits the LAMP1 expression in the nuclei. Thus, in CAPZA1-overexpressing gastric epithelial cells infected with H. pylori, autophagolysosome formation is inhibited and CagA escapes autophagic degradation. These findings identify CAPZA1 as a novel negative regulator of autophaglysosome formation and suggest that deregulation of CAPZA1 expression leads to increased risk of gastric carcinogenesis. Our findings demonstrate that regulation of autophagy by CAPZA1 could be a central mechanisms to account for the effects of CagA on gastric carcinogenesis, and represent new insight for understanding and manipulating the development of gastric cancer.

Free Research Field

分子細菌学

Academic Significance and Societal Importance of the Research Achievements

本研究ではオートファジー制御分子としてCAPZA1を同定し、CAPZA1の新規機能を明示した。今後の研究展開により、これまで隠されていたCAPZA1の本性が次々と明らかにされると期待できる。H. pylori感染者の中でも、胃癌発症者は4％であり、また、除菌後でも胃癌を発症する患者が存在する。これらの患者がなぜ胃癌発症者として選択されるのか明らかではなかった。本研究成果は、H. pylori感染者の中でもCAPZA1発現レベルの高い患者ほど胃発癌リスクが高まる事を示唆しており、今後、より制度の高い胃発癌リスク検診の開発に向けた応用研究が期待される。