ALKALI-LABILE REGIONS AND STRAND BREAKS IN DNA FROM CELLS TREATED WITH DAUNORUBICIN

  • 1 January 1976
    • journal article
    • research article
    • Vol. 7  (1) , 33-46
Abstract
Mouse leukemic lymphocytes (P-288) in culture were exposed to daunorubicin (Dm) and analyzed for DNA damage by alkaline sucrose and neutral (formamide) sucrose gradients. In neutral gradients, the sedimentation rate of DNA from cells treated with 2.5 .times. 10-8 M Dm for brief periods up to 60 min was the same as that of DNA from control cells (i.e., drug-treated for zero time). Extensive DNA damage was apparent in alkaline gradients after treatment of the cells for only 30 min. After treatment for 2 h, single strand damage was evident in both gradients. These results demonstrate the introduction of alkali labile regions in the DNA of cells treated for 45 or 60 min with Dm. The DNA damage is concurrent with inhibition of thymidine incorporation, and both may occur at threshold levels without affecting subsequent growth of P-288 cells after short exposures to low concentrations of the drug.