Mcp. Araujo et al., CHROMOSOME-DAMAGE INDUCED BY DNA TOPOISOMERASE-II INHIBITORS COMBINEDWITH GAMMA-RADIATION IN-VITRO, GENETICS AND MOLECULAR BIOLOGY, 21(3), 1998, pp. 407-413
Combined radiation and antineoplastic drug treatment have important ap
plications in cancer therapy. In the present work, an evaluation was m
ade of two known topoisomerase II inhibitors, doxorubicin (DXR) and mi
toxantrone (MXN), with gamma-radiation. The effects of DXR or MXN on g
amma-radiation-induced chromosome aberrations in Chinese hamster ovary
(CHO) cells were analyzed. Two concentrations of each drug, 0.5 and 1
.0 mu g/ml DXR, and 0.02 and 0.04 mu g/ml MXN, were applied in combina
tion with two doses of gamma-radiation (20 and 40 cGy). A significant
potentiating effect on chromosomal aberrations was observed in CHO cel
ls exposed to 1.0 mu g/ml DXR plus 40 cGy. In the other tests, the com
bination of gamma-radiation with DXR or MXN gave approximately additiv
e effects. Reduced mitotic indices reflected higher toxicity of the dr
ugs when combined with radiation.