Collect. Czech. Chem. Commun. 2004, 69, 603-615

DNA Adduct Formation by the Anticancer Drug Ellipticine and Its Hydroxy Derivatives in Human Breast Adenocarcinoma MCF-7 Cells

Lucie Bořek-Dohalskáa, Eva Freib and Marie Stiborováa,*

a Department of Biochemistry, Faculty of Science, Charles University in Prague, Albertov 2030, 128 40 Prague 2, Czech Republic
b Division of Molecular Toxicology, German Cancer Research Center, In Neuenheimer Feld 280, 69120 Heidelberg, Germany


The cytotoxicity of the antineoplastic agent ellipticine and its 9- and 7-hydroxylated metabolites to human breast adenocarcinoma MCF-7 cells and their ability to generate DNA adducts in these cancer cells were investigated. Ellipticine and its 9-hydroxylated metabolite were found to be toxic to MCF-7 cells with IC50 values of 1.25 and 3.25 μmol l-1 for ellipticine and 9-hydroxyellipticine, respectively. In contrast, no toxicity to these cancer cells was detectable for 7-hydroxyellipticine. The nuclease P1 version of the 32P-postlabeling assay yielded a pattern of ellipticine-DNA adducts with two major and one minor adducts in MCF-7 cells, similar to the pattern of adducts detected in DNA reacted with ellipticine and the reconstituted cytochrome P450 enzyme system in vitro and in DNA in vivo. The identity of two major adducts formed in DNA of MCF-7 cells with those formed by cytochrome P450-mediated ellipticine activation in vitro was confirmed by HPLC of the isolated adducts. 9-Hydroxyellipticine was also capable of inducing DNA adducts in MCF-7 cells, but to a lesser extent. In addition, the adducts generated by 9-hydroxyellipticine were different from those generated by ellipticine. Negligible levels of DNA adducts were detectable in DNA of MCF-7 cells exposed to 7-hydroxyellipticine. The results presented here are the first report showing the formation of covalent DNA adducts with ellipticine in human breast cancer cells in culture, and suggest the formation of covalent DNA adducts as a new mode of antitumor action of ellipticine in breast cancer.

Keywords: Ellipticine; Anticancer drug; Human breast cancer MCF-7 cells; Cytotoxicity; Human cytochrome P450; Activation; DNA adducts; 32P-Postlabeling; Antineoplastic activity.

References: 32 live references.