Use of fluorescence in situ hybridization to measure chromosome aberrations as a predictor of radiosensitivity in human tumour cells

Fluorescence in situ hybridization (FISH) is a potential assay for determining cellular radiosensitivity based on the detection of chromosome damage. This approach was chosen because of its relative simplicity and short assay time. Two radiosensitive and two radioresistant human tumour cell lines were used. The radiosensitive lines were an ovarian carcinoma line (A1847) and a squamous carcinoma line (SCC61). The radioresistant cells were a lung adenocarcinoma line (A549) and second squamous line (SQ20B). Whole chromosome-specific probes were used to detect radiation-induced chromosome aberrations in mitotic cells. Available probes were first screened to characterize the intrinsic chromosome aberrations before irradiation and the appropriate probes (minimum fluorescent spots) were selected for each cell line. Maximum radiation-induced aberrations were found 24 h after irradiation. Dose-response curves corrected for target size (proportion of genome probed) differed for all cell lines. The radiosensitive A1847 cell line showed more induced aberrations compared with the radioresistant A549 cell line, in agreement with the survival data. In contrast, the SQ20B cell line showed more induced chromosome aberrations than the more radiosensitive SCC61 cell line, leading to the hypothesis that the SQ20B cells could tolerate more aberrations. (author)