title: A laser-plasma-produced soft X-ray laser at 89 eV generates DNA double-strand breaks in human cancer cells.
abstract: While it has been expected that X-ray laser will be widely applied to biomedical studies, this has not been achieved to date and its biological effects such as DNA damage have not been evaluated. As a first step for its biological application, we developed a culture cell irradiation system, particularly designed for a plasma-driven soft X-ray laser pulse, to investigate whether the soft X-ray laser is able to induce DNA double strand breaks (DSBs) in living cells or not. The human adenocarcimona cell line A549 was irradiated with the soft X-ray laser at a photon energy of 89 eV and the repair focus formation of the DSBs was assessed by immunofluorescence staining with antiphosphorylated DNA-PKcs (p-DNA-PKcs), ATM (p-ATM) and γ-H2AX antibody. The p-DNA-PKcs, ATM, and γ-H2AX foci were clearly identified after soft X-ray laser irradiation. Furthermore, the increase in the X-ray laser shot number, even from a single shot, results in the increase in p-DNA-PKcs foci. These results are the first evidence that the 89 eV soft X-ray laser is able to induce DSB in living cells. Our study demonstrated that this irradiation system is a useful tool for investigating the radiobiological effect of soft X-ray laser.
authors: Cancer Metastasis Research Team, Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan kat_sato@nirs.go.jp.
authors: Katsutoshi
authors: K
authors: Sato
authors: X-ray Laser Application Group, Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atonic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto, 619-0215, Japan.
authors: Masaharu
authors: M
authors: Nishikino
authors: X-ray Laser Application Group, Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atonic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto, 619-0215, Japan.
authors: Tetsuya
authors: T
authors: Kawachi
authors: Cancer Metastasis Research Team, Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors: Takashi
authors: T
authors: Shimokawa
authors: Advanced Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan.
authors: Takashi
authors: T
authors: Imai
authors: Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, 1-3-3 Nakamichi, Higashinari-ku, Osaka, 537-8511 Japan.
authors: Teruki
authors: T
authors: Teshima
authors: Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors: Hiroaki
authors: H
authors: Nishimura
authors: Laser Electron Accelerator Group, Quantum Beam Science Directorate, Kansai Photon Science Institute, Japan Atonic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto, 619-0215, Japan.
authors: Masaki
authors: M
authors: Kando
mesh_terms: D045744:Cell Line, Tumor; D004249:DNA Damage / Q000235:genetics*; D004273:DNA, Neoplasm / Q000235:genetics* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007834:Lasers; D008175:Lung Neoplasms / Q000235:genetics*; D058626:Plasma Gases; D011829:Radiation Dosage; D014965:X-Rays
chemical_list: D004273:DNA, Neoplasm; D058626:Plasma Gases
keywords: DNA double strand break; laser-plasma soft X-ray laser