5-FLUOROURACIL INCORPORATION IN DNA OF HUMAN-BREAST CARCINOMA-CELLS

Abstract

The presence of 5-fluorouracil (FUra) residues in [mouse leukemia] L1210 DNA was previously demonstrated. These findings were extended to the MCF-7 human breast carcinoma cell line. Cesium sulfate gradient centrifugation was used to separate the MCF-7 RNA and DNA fractions. Alkali and RNase digests were also used to remove any possible RNA contaminating the DNA fraction. The purified DNA was analyzed by high-pressure liquid chromatography following digestion to nucleotides and nucleosides. FUra residues are detectable in the DNA of these human breast carcinoma cells following exposure to either FUra or 5-fluorodeoxyuridine. The extent of FUra incorporation in both MCF-7 RNA and DNA is similar with either fluorinated pyrimidnie. The FUra incorporation in DNA from this human cell line can be enhanced by concurrent incubation with thymidine.