• 1 January 1982
    • journal article
    • research article
    • Vol. 42 (12), 5015-5017
Abstract
It was demonstrated recently that 5-fluorouracil (FUra) residues incorporate in eukaryotic DNA. The present study extends these findings and monitors the effect of methotrexate on the formation of FUra DNA. Methotrexate treatment has little effect on the incorporation of FUra or 5-fluorodeoxyuridine in DNA obtained from MCF-7 human breast carcinoma cells. FUra residues are excised from MCF-7 DNA and methotrexate enhances the excision process. This excision of FUra from eukaryotic DNA may contribute to the cytotoxicity and mutagenicity of these fluorinated pyrimidines.