Inhibition of nitrogen mustard induced DNA repair synthesis by anthracyclines in human peripheral leukocytes.

DNA repair synthesis was induced by nitrogen mustard in human peripheral leukocytes. When the cells were treated with increasing doses of doxorubicin or daunorubicin a decrease of the DNA repair synthesis was recorded. Daunorubicin had a significantly higher inhibitory effect on the DNA repair synthesis compared to doxorubicin. The inhibitory effect by doxorubicin or daunorubicin on nitrogen mustard induced DNA repair synthesis was compared with the inhibitory effect on replicative DNA and RNA synthesis in human lymphoblasts. The inhibition of DNA repair synthesis was significantly lower than the inhibition of replicative DNA synthesis and RNA synthesis for both drugs.