title: Prediction of cellular radiosensitivity from DNA damage induced by gamma-rays and carbon ion irradiation in canine tumor cells.
abstract: Diseases of companion animals are shifting from infectious diseases to neoplasms (cancer), and since radiation therapy is one of the effective choices available for cancer treatment, the application of radiotherapy in veterinary medicine is likely to increase. However tumor tissues have different radiosensitivities, and therefore it is important to determine the intrinsic radiosensitivity of tumors in individual patients in advance of radiotherapy. We have studied the relationship between the surviving cell fraction measured by a clonogenic assay and DNA double strand breaks detected by a comet assay under neutral conditions in three canine tumor cell lines, after gamma-ray and carbon ion irradiation. In all the cell lines, cell death assessed by the clonogenic assay was much higher following irradiation with carbon ions than with gamma-rays. The initial and residual (4 hr) DNA damage due to gamma-ray and carbon ion irradiation were higher in a radiosensitive cell line than in a radioresistant cell line. The surviving cell fraction at 2 Gy (SF2) showed a tendency for correlation with both the initial and residual DNA damage. In particular, the residual damage per Gy was significantly correlated with SF2, regardless of the type of radiation. This indicates that cellular radiosensitivity can be predicted by detection of radiation-induced residual DNA damage.
authors.affiliation: Research Group for Biotechnology Development, Japan Atomic Energy Research Institute-Takasaki, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Wada
authors.forename: Tran
authors.initials: T
authors.lastname: Van Khoa
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Tomoo
authors.initials: T
authors.lastname: Funayama
authors.forename: Kikumi
authors.initials: K
authors.lastname: Ogihara
authors.forename: Shunji
authors.initials: S
authors.lastname: Ueno
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Ito
mesh_terms: D000818:Animals; D002244:Carbon / Q000737:chemistry; D016923:Cell Death / Q000235:genetics / Q000528:radiation effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000528:radiation effects*; D020552:Comet Assay / Q000662:veterinary; D004249:DNA Damage; D004283:Dog Diseases / Q000532:radiotherapy*; D004285:Dogs; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D009369:Neoplasms / Q000532:radiotherapy / Q000662:veterinary*; D011836:Radiation Tolerance / Q000502:physiology*
chemical_list: D002244:Carbon