title: Initial radiation-induced DNA damage in human tumour cell lines: a correlation with intrinsic cellular radiosensitivity.
abstract: The role of the initial DNA double-strand breaks (dsb) as a determinant of cellular radiosensitivity was studied in human breast and bladder cancer cell lines. Cell survival was measured by monolayer colony-forming assay as appropriate and differences in radiosensitivity were seen (alpha-values ranged from 0.12 to 0.54). After pulsed-field gel electrophoresis (PFGE) the initial slopes of dose-response curves were biphasic with a flattening of the curves above 30 Gy. When the frequency of DNA dsb induction was assessed using a mathematical model based on the DNA fragment size distribution into the gel lane, we found a statistically significant relationship between the number of DNA dsb induced and the corresponding alpha-values and fraction surviving after 2Gy (P = 0.0049 and P = 0.0031 respectively). These results support the view that initial damage is a major determinant of cell radiosensitivity.
authors.affiliation: Departamento de Radiologia, Hospital Universitario, Facultad de Medicina, Granada, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Ruiz de Almodóvar
authors.forename: M I
authors.initials: MI
authors.lastname: Núñez
authors.forename: T J
authors.initials: TJ
authors.lastname: McMillan
authors.forename: N
authors.initials: N
authors.lastname: Olea
authors.forename: C
authors.initials: C
authors.lastname: Mort
authors.forename: M
authors.initials: M
authors.lastname: Villalobos
authors.forename: V
authors.initials: V
authors.lastname: Pedraza
authors.forename: G G
authors.initials: GG
authors.lastname: Steel
mesh_terms: D001943:Breast Neoplasms; D002453:Cell Cycle / Q000528:radiation effects*; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects*; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008433:Mathematics; D008962:Models, Theoretical; D014407:Tumor Cells, Cultured / Q000528:radiation effects*; D001749:Urinary Bladder Neoplasms
chemical_list: D004273:DNA, Neoplasm