Topoisomerase II-mediated DNA damage of episomes in tumor-bearing mice.

摘要: Observations of cells in culture have demonstrated that, for many antitumor agents, topoisomerase II-mediated DNA damage relates to cytotoxicity. However, there is no evidence tumor-bearing animals suggest that such agents induce solid tumors or reflects inhibition tumor growth. To address this question, a mouse fibroblast cell line neoplastically transformed by an episomal element containing the v-Ha-ras and bovine papillomavirus genes was utilized measure II-induced growth derived from line. Using II inhibitor amsacrine, found be sensitive indicator vivo. The breaks induced single i.v. injections amsacrine were protein linked occurred preferentially regulatory regions. A strong correlation between suppression episome demonstrated.