@misc{oai:repo.qst.go.jp:00071311,
 author = {Sato, Katsutoshi and Imai, Takashi and Shimokawa, Takashi and 佐藤 克俊 and 今井 高志 and 下川 卓志},
 month = {Oct},
 note = {The aim of this study is to establish X-ray resistant cell lines by repeated X-ray irradiation, and to assess the characteristics of these cells to see whether they are also resistant to carbon ion beams (C-ion). The mouse adenocarcinoma cell line NRS1 was irradiated 6 times with 10Gy of X-ray. After 60 Gy of X-ray irradiation, X-ray resistant cancer cells, named NRS1-X60, as well as 10 subclones, which were selected from NRS1-X60 cells, were established. Surprisingly, NRS1-X60 cells and all subclones were also resistant to 290 MeV/n of C-ion irradiation in comparison with NRS1. Additionally, heterochromatin focus numbers were significantly increased in the X-ray/C-ion resistant subclones and NRS1-X60 cells, and they strongly correlated with both X-ray and C-ion resistance. Moreover, the focus number of gamma-H2AX remaining after X-ray or C-ion irradiation was lower in NRS1-X60 and the X-ray/C-ion resistant subclones compared to that of NRS1 cells. Our results showed that the repeated X-ray irradiations can generate not only X-ray resistance but also C-ion resistance, and the increase of heterochromatin focus number might be a marker of radioresistance., The 72nd Annual Meeting of the Japanese Cancer Association},
 title = {Heterochromatin focus number correlates with X-ray and carbon ion beam resistance in cancer cells},
 year = {2013}
}