title: The anticancer drug ellipticine forms covalent DNA adducts, mediated by human cytochromes P450, through metabolism to 13-hydroxyellipticine and ellipticine N2-oxide.
abstract: Ellipticine is an antineoplastic agent, the mode of action of which is considered to be based on DNA intercalation and inhibition of topoisomerase II. We found that ellipticine also forms the cytochrome P450 (CYP)-mediated covalent DNA adducts. We now identified the ellipticine metabolites formed by human CYPs and elucidated the metabolites responsible for DNA binding. The 7-hydroxyellipticine, 9-hydroxyellipticine, 12-hydroxyellipticine, 13-hydroxyellipticine, and ellipticine N(2)-oxide are generated by hepatic microsomes from eight human donors. The role of specific CYPs in the oxidation of ellipticine and the role of the ellipticine metabolites in the formation of DNA adducts were investigated by correlating the levels of metabolites formed in each microsomal sample with CYP activities and with the levels of the ellipticine-derived deoxyguanosine adducts in DNA. On the basis of this analysis, formation of 9-hydroxyellipticine and 7-hydroxyellipticine was attributable to CYP1A1/2, whereas production of 13-hydroxyellipticine and ellipticine N(2)-oxide, the metabolites responsible for formation of two major DNA adducts, was attributable to CYP3A4. Using recombinant human enzymes, oxidation of ellipticine to 9-hydroxyellipticine and 7-hydroxyellipticine by CYP1A1/2 and to 13-hydroxyellipticine and N(2)-oxide by CYP3A4 was corroborated. Homologue modeling and docking of ellipticine to the CYP3A4 active center was used to explain the predominance of ellipticine oxidation by CYP3A4 to 13-hydroxyellipticine and N(2)-oxide.
authors.affiliation: Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic. stiborov@natur.cuni.cz
authors.forename: Marie
authors.initials: M
authors.lastname: Stiborová
authors.forename: Jan
authors.initials: J
authors.lastname: Sejbal
authors.forename: Lucie
authors.initials: L
authors.lastname: Borek-Dohalská
authors.forename: Dagmar
authors.initials: D
authors.lastname: Aimová
authors.forename: Jitka
authors.initials: J
authors.lastname: Poljaková
authors.forename: Kristina
authors.initials: K
authors.lastname: Forsterová
authors.forename: Martina
authors.initials: M
authors.lastname: Rupertová
authors.forename: Jirí
authors.initials: J
authors.lastname: Wiesner
authors.forename: Jirí
authors.initials: J
authors.lastname: Hudecek
authors.forename: Manfred
authors.initials: M
authors.lastname: Wiessler
authors.forename: Eva
authors.initials: E
authors.lastname: Frei
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D018736:DNA Adducts; D004611:Ellipticines / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008862:Microsomes, Liver / Q000378:metabolism; D008958:Models, Molecular; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D018736:DNA Adducts; D004611:Ellipticines; D011994:Recombinant Proteins; C034192:ellipticine; D003577:Cytochrome P-450 Enzyme System