Reaction of beta-lapachone and related naphthoquinones with 2-mercaptoethanol: a biomimetic model of topoisomerase II poisoning by quinones.

K. Neder, L. J. Marton, Leroy-Fong Liu, B. Frydman

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

1,2-Naphthoquinones, such as beta-lapachone, 4-alkoxy-1,2-naphthoquinones, and tetrahydrofuran-1,2-naphthoquinones, react rapidly with 2-mercaptoethanol in benzene to give 1,4-, 1,2-, 1,3- and 1,6-Michael-type adducts that are formed by the addition of the thiol group to the quinone ring. Menadione (2-methyl-1,4-naphthoquinone) reacts with the thiol reagent very slowly under the same reaction conditions. Although the formation of the adducts can be followed by 1H-NMR, attempts to isolate the adducts failed due to their retroconversion to the starting products. On addition of a Lewis acid, however, the adducts undergo cyclization reactions that give stable derivatives that can be isolated and characterized. Determination of the structures of the derivatives allowed for the identification of the adducts from which they originated. Thus, beta-lapachone and 2,3-dinordunnione underwent 1,4- and 1,2-Michael type additions to the quinone ring, while 4-pentyloxy-1,2-naphthoquinone underwent two simultaneous Michael additions to the quinone ring of the naphthoquinone. Menadione underwent a single 1,3-addition. The alkylation rates of the thiol group of 2-mercaptoethanol by the naphthoquinones parallel the naphthoquinones efficiencies in inducing DNA cleavage through DNA-bound topoisomerase II. These results support our hypothesis that the cytotoxic effect of the naphthoquinones derive, at least in part, from their alkylation of exposed thiol residues on the topoisomerase II-DNA complex.

Original languageEnglish
Pages (from-to)465-474
Number of pages10
JournalCellular and molecular biology (Noisy-le-Grand, France)
Volume44
Issue number3
Publication statusPublished - May 1998
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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