Reversible and formaldehyde-mediated covalent binding of a bis-amino mitoxantrone analogue to DNA. Issue 20 (4th May 2016)

• Record Type: Journal Article
• Authors: Konda, Shyam K.; Kelso, Celine; Pumuye, Paul P.; Medan, Jelena; Sleebs, Brad E.; Cutts, Suzanne M.; Phillips, Don R.; Collins, J. Grant
• Is Part Of: Organic & biomolecular chemistry. Volume 14:Issue 20(2016)
• Page Start: 4728
• Page End: 4738
• Publication Date: 2016-05-04
• Subjects: Chemistry, Organic -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1039/c6ob00561f
• Languages: English
• ISSNs: 1477-0520

Abstract

Abstract : The ability of the anthracenedione anticancer drug WEHI-150 to form covalent adducts with DNA, after activation by formaldehyde, has been studied by mass spectrometry, HPLC and NMR spectroscopy. Abstract : The ability of a bis-amino mitoxantrone anticancer drug (named WEHI-150) to form covalent adducts with DNA, after activation by formaldehyde, has been studied by electrospray ionisation mass spectrometry and HPLC. Mass spectrometry results showed that WEHI-150 could form covalent adducts with d(ACGCGCGT)2 that contained one, two or three covalent links to the octanucleotide, whereas the control drugs (daunorubicin and the anthracenediones mitoxantrone and pixantrone) only formed adducts with one covalent link to the octanucleotide. HPLC was used to examine the extent of covalent bond formation of WEHI-150 with d(CGCGCG)2 and d(CG 5Me CGCG)2 . Incubation of WEHI-150 with d(CG 5Me CGCG)2 in the presence of formaldehyde resulted in the formation of significantly greater amounts of covalent adducts than was observed with d(CGCGCG)2 . In order to understand the observed increase of covalent adducts with d(CG 5Me CGCG)2, an NMR study of the reversible interaction of WEHI-150 at both CpG and 5Me CpG sites was undertaken. Intermolecular NOEs were observed in the NOESY spectra of d(ACGGCCGT)2 with added WEHI-150 that indicated that the drug selectively intercalated at the CpG sites and from the major groove. In particular, NOEs were observed from the WEHI-150 H2, 3 protons to the H1′ protons of G3 and G7 and from the H6, 7 protons to the H5 protons of C2 and C6 . By contrast, intermolecular NOEs were observed between the WEHI-150 H2, 3 protons to the H2′′ proton of the 5Me C3 in d(CG 5Me CGCG)2, and between the drug aliphatic protons and the H1′ proton of G4 . This demonstrated that WEHI-150 preferentially intercalates at 5Me CpG sites, compared to CpG sequences, and predominantly via the minor groove at the 5Me CpG site. The results of this study demonstrate that WEHI-150 is likely to form interstrand DNA cross-links, upon activation by formaldehyde, and consequently exhibit greater cytotoxicity than other current anthracenedione drugs.