The Anticancer Drug Ellipticine Forms Covalent DNA Adducts, Mediated by Human Cytochromes P450, through Metabolism to 13-Hydroxyellipticine and EllipticineN2-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.

First principles view on chemical compound space: Gaining rigorous atomistic control of molecular properties

“…Structural data as well as studies on drug analogues are readily available. [74,75] We will probe the versatility of the linearizing scheme for controlling ellipticine-derivatives/DNA binding, isolated in gas phase and with fixed geometry. [76] Clearly, for the eventual control of ligand binding, the property of interest is not the potential energy of interaction but rather the free energies of binding: solvation or entropic contributions can be crucial, as is well known in general, [77] and in the particular case of ellipticine.…”

Ellipticine derivative NSC 338258 represents a potential new antineoplastic agent for the treatment of multiple myeloma

“…Previous molecular studies suggested that ellipticine acted primarily through its binding to nucleic acids and inhibition of topoisomerase II (topo II) and topo II -mediated DNA damage (14). Cytochrome P450-dependent oxidation at the 7-or 9-carbon position has been shown to promote DNA intercalation and adduct formation, thereby enhancing the cytotoxic potential of these agents (15). Additionally, selection for ellipticine resistance in a Chinese hamster lung cell line resulted in a phenotype that was cross-resistant to all known topoisomerase-targeting agents as well as several additional P-glycoprotein substrates (16,17).…”

Quantum-Mechanical Studies of Reactions Performed by Cytochrome P450 Enzymes

“…In experiments, aromatic N-oxides formed by CYPs have been found for a large number of compounds, primarily with pyridine, [104][105][106][107][108][109] pyrimidine, 110 and quinoline fragments. 111 However, no N-oxides of nitrogen atoms in five-membered aromatic rings have been found.…”