Auromomycin-induced DMA Damage and Repair in Human Leukemic Lymphoblasts (CCRF-CEM Cells)1

An alkaline elution procedure was used to study the nature of DNA damage induced by auromomycin, an antitumor protein, in human leukemic lymphoblasts (CCRF-CEM cells). The filter elu tion of drug-treated cells at pH 12.2 and 9.6 showed induction of both single and double strand DNA breaks. The DNA strand scission activities were linear in relation to drug concentration. The frequency of single strand breaks was higher than that of the double strand breaks. Protein-associated DNA single strand breaks were also detected in alkaline elution of drug-treated cells when a proteinase K digestion step was included in the assay protocol. The auromomycin-induced single strand breaks were repaired to almost completion within 8 h of postincubation of DNA-damaged cells whereas the repair of double strand breaks