Basic Medicine, Molecular and Cellular Biology

Radiation Biology

Radiation Biology Saves the Society

Medical Sciences Course

  • Master / Doctoral Degree

Faculty

HOSOI, YoshioHOSOI, Yoshio
HOSOI, Yoshio

Professor, M.D. Ph.D.

*Concurrent Position

Research Theme

  • Radiosensitization through modification of DNA double strand breaks repair enzymes
  • Activity of mTOR under nutrient starvation condition and cellar radiation sensitivity
  • Effects of low doses of ionizing radiation
Research Keywords:

ionizing radiation, ATM, DNA-PK, mTOR, low dose radiation

Technical Keywords:

X-irradiation, western blotting, cell culture

Laboratory Introduction

1. Basic research for radiation oncology.
(1). Radiosensitization through modification of DNA double strand breaks repair enzymes.
ATM, which is the responsible gene for radiosensitive human genetic disease, ataxia-telangiectasia (AT), contributes to DNA double-strand breaks repair. We are investing relationship between ATM and radioresistance of cancer stem cell.
(2). Activity of mTOR under nutrient starvation condition and cellar radiation sensitivity.
The presence of radiation resistant cells in solid human tumors is one of the major reasons why radiotherapy fails to eradiate such neoplasms. The presence of unperfused regions containing cells under hypoxic and nutrient-starvation conditions may contribute to resistance to ionizing radiation. To investigate the effects or nutrient-starvation conditions on radiation sensitivity, we are investigating relationship between activity of mammalian target of rapamycin complex 1 (mTORC1), whichi functions as a nutrient/energy/redox sensor, and radiation sensitivity.
2. Effects of low doses of ionizing radiation
Low dose (0-0.5 Gy) total body irradiation (TBI) has been reported to have different effects from those induced by high dose TBI, such as radioadaptive response and augmentation of immune response. It has been reported that low dose rate TBI increased incidences of myocardial infarction and brain infarction. To clarify the molecular mechanisms underlying increased incidences of these diseases, we are investigating effects of ionizing radiation on cultured human endothelial cells.

Figure 1. A 250 kV X-ray generator for irradiation of animals

Figure 1. A 250 kV X-ray generator for irradiation of animals

Figure 2. A 150 kV X-ray generator for irradiation of cells

Figure 2. A 150 kV X-ray generator for irradiation of cells

Recent Publications

  • Morita A, Murakami T, Morinaga T, Tanimoto K, Hosoi Y: Requirement of mitochondria for ATM activation by extranuclear oxidative stress in cultured human hepatoblastoma cell line HepG2 cells. Biochemical and Biophysical Research Communications 443: 1286-90, 2014.
  • Enomoto A, Fukasawa T, Takamatsub N, Itob M, Moritac A, Hosoi Y, Miyagawa K: The HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin modulates radiosensitivity by downregulating serine/threonine kinase 38 via Sp1 inhibition. European Journal of Cancer 49: 3547-3558, 2013.
  • Tanigawa K, Hosoi Y, Hirohashi N, Iwasaki Y, Kamiya K: Loss of life after evacuation: lessons learned from the Fukushima accident. Lnacet 379: 889-891, 2012.