OBJECTIVES: Ellipticine is a potent antineoplastic agent exhibiting multiple mechanisms of action with promising brain tumor specificity. This anticancer agent should be considered a pro-drug, whose pharmacological efficiency and/or genotoxic side effects are dependent on its cytochrome P450 (CYP) - and/or peroxidase-mediated activation to species forming covalent DNA adducts. Ellipticine can also act as an inhibitor or inducer of biotransformation enzymes, thereby modulating its own metabolism leading to its genotoxic and pharmacological effects. The toxicity of ellipticine to U87MG glioblastoma cells and mechanisms of its action to these cells are aims of this study. METHODS: Ellipticine metabolites formed in U87MG cells were analyzed using HPLC. Covalent DNA modifications by ellipticine were detected by 32P-postlabeling. CYP enzyme expression was examined by QPCR and Western blot. RESULTS: U87MG glioblastoma cell proliferation was efficiently inhibited by ellipticine. This effect might be associated with formation of two covalent ellipticine-derived DNA adducts, identical to those formed by 13-hydroxy- and 12-hydroxyellipticine, the ellipticine metabolites generated by CYP1A1, 1B1 and 3A4, lactoperoxidase and cyclooxygenase 1, the enzymes expressed in U87MG cells. Moreover, by inducing CYP1B1, 3A4 and 1A1 enzymes in U87MG cells, ellipticine increases its own enzymatic activation, thereby enhancing its own genotoxic and pharmacological potential in these cells. Ellipticine concentration used for U87MG cell treatment is extremely important for its pharmacological effects, as its metabolite profiles differed substantially predicting ellipticine to be either detoxified or activated. CONCLUSION: The results found in this study are the first report showing cytotoxicity and DNA adduct formation by ellipticine in glioblastomas.

Department of Biochemistry Faculty of Science Charles University Prague Czech Republic

Cytochrome b5 plays a dual role in the reaction cycle of cytochrome P450 3A4 during oxidation of the anticancer drug ellipticine

Heterologous expression of human cytochrome P450 2S1 in Escherichia coli and investigation of its role in metabolism of benzo[a]pyrene and ellipticine

The anticancer drug ellipticine activated with cytochrome P450 mediates DNA damage determining its pharmacological efficiencies: studies with rats, Hepatic Cytochrome P450 Reductase Null (HRN™) mice and pure enzymes

Formation of DNA adducts by ellipticine and its micellar form in rats - a comparative study

Ellipticine cytotoxicity to cancer cell lines - a comparative study