A correlation between radiation sensitivity and initial chromatid breaks in cancer cell lines revealed by Calyculin A-induced premature condensation

Abstract Three human malignancy cell lines were irradiated with 60Co γ-rays. Initial chromatid breaks were measured by using the chemically induced premature chromosome condensation technique. Survival curves of cells exposed to gamma rays was linear-quadratic while the efficiency of Calyculin A in inducing PCC of G2 PCC was about five times more than G1 PCC. A dose-dependent increase in radiation-induced chromatid/isochromatid breaks was observed in G1 and G2 phase PCC and a nearly positive linear correlation was found between cell survival and chromatin breaks. This study implies that low LET radiation-induced chromatid/isochromatid breaks can potentially be used to predict the radiosensitivity of tumor cells either in in vitro experimentation or in in vivo clinical radiotherapy.