Professor Masanori Hatakeyama of the University of Tokyo Graduate School of Medicine and colleagues have found that protein phosphatase (SHP1) is an enzyme that suppresses the carcinogenic activity of the protein CagA produced by Helicobacter pylori.Furthermore, we found that the expression of SHP1 was suppressed in the cells of the stomach infected with Epstein-Barr (EB) virus, and the carcinogenic activity of the Helicobacter pylori CagA protein was enhanced.This result is the first in the world to clarify the mechanism by which bacteria and viruses work together to promote the development of cancer in humans.This research is a collaboration with researchers from the Graduate School of Medicine, Chiba University and the Graduate School of Medicine, the University of Tokyo.

 Helicobacter pylori is said to increase the risk of developing gastric cancer, and it has been reported that almost all H. pylori detected in Japan are CagA-positive H. pylori, which produces the protein CagA.CagA injected into gastric cells by Pyrroli bacteria is tyrosine-phosphorylated by phosphorylating enzymes (Src family kinase and Abl kinase), and then binds to tyrosine dephosphorylating enzyme (phosphatase) SHP2 to promote the development of gastric cancer. increase. Dephosphorylation of CagA is important in suppressing canceration, but SHP2 does not have the ability to dephosphorylate CagA.

 We have now identified SHP2, a sibling of SHP1, as an enzyme that dephosphorylates the Helicobacter pylori protein CagA. As a result of tyrosine dephosphorylation by SHP1, the carcinogenic activity of the CagA protein was neutralized, suggesting that SHP1 is a molecule that suppresses the development of gastric cancer.On the other hand, EB virus infection to cancer cells is known in about 10% of gastric cancer cases, and as a result of this co-infection, the site called the promoter of the SHP1 gene is highly methylated, and as a result, the expression of SHP1 is suppressed. It was found that the carcinogenic activity of the Helicobacter pylori CagA protein was enhanced.It is the first time in the world to elucidate the link between carcinogenic bacteria and carcinogenic viruses in the development of human cancer.

Tokyo University

Established in the 10th year of the Meiji era.A university with the longest history in Japan and at the forefront of Japanese knowledge

The University of Tokyo was established in 1877 (Meiji 10) by integrating the Tokyo Kaisei School and the Tokyo Medical School.Since its establishment, it has developed education and research in a unique way in the world as a leading university in Japan and an academic center for the fusion of East and West cultures.As a result, many human resources have been produced in a wide range of fields, and many research achievements […]

Chiba University

Fostering human resources who will open up the next generation.To a future-oriented university that shines in the world

Chiba University has 10 faculties, 7 graduate schools / faculties, and a large number of affiliated facilities, and has specialized knowledge and skills, high problem-solving ability, high intelligence, ethical standards, and rich humanity, and has an interdisciplinary perspective. We aim to develop human resources who can play an active role internationally.Actively promote the enhancement of liberal arts education and the internationalization of educational activities, which are the basis of this […]

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