Radiation-induced DNA damage and repair evaluated with 'Comet assay' in human ovarian carcinoma cell lines with different radiosensitivities

Radiation-induced DNA damage and kinetics of DNA repair was evaluated in th ree human ovarian carcinoma cell lines (i.e. CH-1, A-2780 and SKOV-3) with different sensitivities to ionizing radiation and radiation-induced apoptos is with the aid of single cell gel electrophoresis (SCGE, the comet assay). A good correlation was found between the initial level of DNA breaks and r adiation induced apoptosis in CH-1 and SKOV-3 cell lines. While the radiati on-sensitive CH-1 cell line manifested the highest level of initial DNA bre akage and a significant delay in DNA break rejoining, the inverse correlati on was found in the radiation-resistant cell line SKOV-3. Intermediate init ial level of breaks was induced in the A-2780 cell line characterized by th e intermediate sensitivity to X-ray radiation in comparison to CH-1 and SKO V-3 cells, however, the kinetics of DNA repair was comparable with radiatio n-resistant cell line SKOV-3. Our data suggest that the comet assay could b e a promising tool for prediction of intrinsic cell radiosensitivity. This method might be considered as a supplementary technique to the more reliabl e but time consuming clonogenic assay.