The interaction of dianhydrogalactitol with DNA in cultured Yoshida sarcoma cells.

Using alkaline sucrose gradient sedimentation centrifugation it was found that treatment of Yoshida sarcoma cells in culture for 1 h with increasing concentrations of dianhydrogalactitol (DAG) enhanced the sedimentation rate of DNA in a dose-dependent manner. There was no difference between the amount of protein which co-sedimented with DNA released from treated and untreated cells. When DNA was extracted from the cells using a p-amino-salicylate-phenol mixture, the protein content of DNA seemed not to be affected by DAG. The possibility that DAG could form interstrand cross-linking in cellular DNA was suggested from renaturation studies. The appearance of a fast sedimenting DNA in the alkaline sucrose gradient and the evidence for a cross-linked DNA detected by renaturation technique, only appeared later than 6 h after treatment. A similar delayed effect on the depression in the rate of DNA synthesis was also observed. These data suggest that the inhibition of DNA synthesis may be related to the delayed formation of DNA interstrand cross-linked.