[The effect of adriamycin derivatives in combination with x-rays on MeWo and Be11 cells]

The survival rate of human melanoma cells after X-ray irradiation, treatment with adriamycin derivatives and combined treatment with X-rays and adriamycin derivatives was measured by means of the colony formation test. After X-ray irradiation the melanoma cells showed a high resistance for cell survival. In all tests the Be11-cells were more resistant than MeWo-cells. On combined exposure especially with higher doses of adriamycin derivatives, both cell lines showed the interesting effect, that with increasing concentration the survival rate decreased whereas the D(o) increased. Aclacinomycin-A (ACM-A) and Pirarubicin reduced recovery processes after X-ray irradiation. Therefore Be11-cells showed a four times higher DMF (dosis modifying factor) after ACM-A-treatment than MeWo-cells. Low ACM-A-concentrations combined with low X-ray doses showed on both cell lines supraadditive effects. The effect of pirarubicin was in most of the tests only additive. Compared with ACM-A, pirarubicin was less cytotoxic, showed a larger therapeutic range, caused a smaller D(o) and Dq and had a supraadditive effect in low concentrations on both cell lines. For clinical combined therapy with patients ACM-A is probably better suited than pirarubicin.