Reversible and formaldehyde-mediated covalent binding of a bis-amino mitoxantrone analogue to DNA

Abstract

Collins, J. (2016). Reversible and formaldehyde-mediated covalent binding of a bis-amino mitoxantrone analogue to DNA. Organic and Biomolecular Chemistry, 14 (20), 4728-4738. Reversible and formaldehyde-mediated covalent binding of a bis-amino mitoxantrone analogue to DNA AbstractThe 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(CG5MeCGCG)2. Incubation of WEHI-150 with d(CG5MeCGCG)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(CG5MeCGCG)2, an NMR study of the reversible interaction of WEHI-150 at both CpG and 5MeCpG 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 5MeC3 in d(CG5MeCGCG)2, and between the drug aliphatic protons and the H1′ proton of G4. This demonstrated that WEHI-150 preferentially intercalates at 5MeCpG sites, compared to CpG sequences, and predominantly via the minor groove at the 5MeCpG 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. Disciplines Medicine and Health Sciences | Social and Behavioral Sciences Publication DetailsKonda, S., Kelso, C., Pumuye, P. P., Medan, J., Sleebs, B. E., Cutts, S. M., Phillips, D. R. & Collins, J. (2016

Isolation and structural analysis of the covalent adduct formed between a bis-amino mitoxantrone analogue and DNA: a pathway to major–minor groove cross-linked adducts

“…The molecular modelling investigations were carried out using HyperChem Release 7.5 software as previously described. 10 Duplex B-DNA was generated from the nucleic acid database. Energy restraints were added to maintain the H-bonds as expected in duplex DNA during the optimisation procedures.…”

“…As a consequence WEHI-150 can more rapidly and more extensively form covalent adducts with DNA than mitoxantrone. 10 In order to further develop the anthracenedione class of anticancer drugs it is important to determine the structure of a mitoxantrone-or mitoxantrone derivative-DNA adduct. Previous studies have demonstrated that WEHI-150 preferentially intercalates and then forms covalent adducts with DNA at CpG sites.…”

“…Previous studies have demonstrated that WEHI-150 preferentially intercalates and then forms covalent adducts with DNA at CpG sites. 10 In addition, WEHI-150 forms significantly more covalent adducts when the cytosine at the CpG site is methylated at the C-5 position ( 5Me CpG). 10 Consequently, we sought to isolate by HPLC the major covalent adduct formed between WEHI-150 and the hexanucleotide d(CG 5Me CGCG) 2 and then examine its structure by NMR spectroscopy.…”

Synthesis and DNA binding of 6-(alkylamino)indolo[1,2-b][2,7]naphthyridine-5,12-quinones

“…We have previously synthesized and utilized the indolo [1,2-b] [2,7]naphthyridine-5,12-dione (6) ring system to forge several members of the 6H-pyrido [4,3-b]carbazole family of antitumor alkaloids, including ellipticine (7), 9-methoxyellipticine (8), olivacine (9), 13-oxoellipticine (10), 7,8,9,10-tetrafluoroellipticine (11), and ellipticine quinone (12) [15][16][17][18][19][20] (Figure 2). A variation of our method allowed for the synthesis of 10Hpyrido [2,3-b]carbazoles (13) 21 and 6,11-disubstituted-benzo[b]carbazoles (14). 22 The shape similarity of quinone (6) with that of ellipticine quinone (12) and calothrixin B (15), both of which display antitumor activity, [23][24][25] suggested that it would be fruitful to examine indoloquinone 6 and its amino-substituted derivatives for DNA binding, given the known enhancement of DNA binding and resulting biological activity imparted by the alkylamino side chains in antitumor quinones 2-5.…”

“…The antitumor activity and DNA affinity of amino-substituted quinones is well established, [1][2][3][4] and several drugs in this category have seen utility in the cancer clinic; for example, mitomycin (1), 5,6 ametantrone (2), 7 mitoxantrone (3), 8,9 pixantrone (4), [10][11][12] and WEHI-150 (5) 13,14 (Figure 1).…”