量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果(学会誌発表論文、学会発表、研究開発報告書、特許等)を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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The aim of this study is to investigate whether the repetition of carbon-ion beam (C-ion) irradiation generates the C-ion resistant cancer cell and, whether the mechanisms are different between the C-ion and X-ray resistance. To establish the C-ion resistant cancer model, we repeatedly irradiated in vivo the mouse squamous cell carcinoma cell line NRS1, SCCVII, and mouse mammary carcinoma cell MCa4 with 290 MeV/n of C-ion. In the presence, the NRS1 and MCa4 cell were respectively irradiated with 60Gy and 75Gy for total dose. We will irradiate these tumors until 90Gy. While we irradiated SCCVII cell with single dose 15Gy of C-ion and then transplanted into another mouse after 2 weeks of irradiation, tumor is no longer grown. In vitro, we established the NRS1-C30 cell by the irradiation with total dose 30Gy of C-ion. We will elucidate whither C-ion and X-ray resistance is generated in NRS1-C30 cell. To compare the mechanisms of C-ion resistance with that of X-ray resistance, we established the X-ray resistant NRS1-X60 cell in vitro by the repeated X-ray irradiations. Surprisingly, NRS1-X60 cell is 23-folds resistance to C-ion compared with NRS1. However, the RBE of C-ion at D10 is approximately same in both cells.