Mechanism of low dose(rate) radiation induced tumor development by using intestinal stem cell organoid system

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K00553
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: Hiroshima University
• Principal Investigator: Sasatani Megumi (豊島めぐみ) 広島大学, 原爆放射線医科学研究所, 准教授 (80423052)
• Co-Investigator(Kenkyū-buntansha): 河合 秀彦 広島大学, 医系科学研究科(薬), 准教授 (30379846) ; 神谷 研二 広島大学, 医療政策室, 特任教授 (60116564)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 放射線 / 発がん / 低線量(率) / 幹細胞 / 動物モデル

Outline of Final Research Achievements

It is known that radiation-induced cancer risk in childhood is higher than in adulthood in human. Thus, age at exposure is a major effect modifier of radiation-induced cancer. Given that the Fukushima Daiichi Nuclear Power Plant accident in Japan is reviving concern about cancer risk at low radiation doses, especially in childhood, clarifying the mechanism of susceptibility for radiation-induced carcinogenesis in childhood needs to be investigated in each organ. The application of animal models might be useful for understanding the mechanism of age-dependent cancer risk. Here, we elucidated the age dependence of the exposure in model mice of intestinal tumors, and analyzed the effects of radiation response and age on irradiation on carcinogenesis, including cell competition of small intestinal stem cells. And our results suggest that there is the relationship between intestinal morphogenesis and radiation-induced cancer risk.

Free Research Field

放射線発がん

Academic Significance and Societal Importance of the Research Achievements

福島原発事故後、胎児期・小児期被ばくにおける発がんリスクの増加が懸念されている。しかしながら、放射線発がんにおける被ばく時年齢依存性の有無とその分子メカニズムについては未だ未解明の部分が多い。そのため、本研究成果は、動物モデルを用いて放射線発がんにおける被ばく時年齢依存性の機構解明に関する新規知見が得られており、学術的に重要といえる。また、各年齢における放射線発がんリスクとその分子機構が解明されれば、放射線発がんリスク評価のみならず放射線防護体系の基盤確立に貢献できることが期待される。