Ethanol-induced cell sensitization to bleomycin cytotoxicity and the inhibition of recovery from potentially lethal damage.

The cytotoxic effect of bleomycin toward mouse mammary carcinoma FM3A cells in culture was markedly potentiated by exposure of the cells to ethanol either before or after treatment with bleomycin. Ethanol-induced cell sensitization to bleomycin cytotoxicity produced a decrease in cell survival which became dependent on dose and time of drug treatment. The sensitizing effect of ethanol after drug treatment was maximum when ethanol exposure immediately followed drug treatment, and it rapidly decreased as the time interval between the two treatments was increased. Ethanol did not sensitize cells to the cytotoxic effects of cis-diamminedichloroplatinum(II) and macromomycin. These results are discussed in terms of the ability of ethanol to inhibit cell recovery from potentially lethal damage after bleomycin treatment.