Formation of Bulky DNA Adducts by Non-Enzymatic Production of 1,2-Naphthoquinone-Epoxide from 1,2-Naphthoquinone under Physiological Conditions

Quinones may be formed metabolically or abiotically from environmental pollutants and polycyclic aromatic hydrocarbons (PAHs); many are recognized as toxicological intermediates that cause a variety of deleterious cellular effects including mutagenicity. The PAH-o-quinone, 1,2-naphthoquinone (1,2-NQ...

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Veröffentlicht in:Chemical research in toxicology 2019-09, Vol.32 (9), p.1760-1771
Hauptverfasser: Matsui, Takuya, Yamada, Naohito, Kuno, Hideyuki, Kanaly, Robert A
Format: Artikel
Sprache:eng
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Zusammenfassung:Quinones may be formed metabolically or abiotically from environmental pollutants and polycyclic aromatic hydrocarbons (PAHs); many are recognized as toxicological intermediates that cause a variety of deleterious cellular effects including mutagenicity. The PAH-o-quinone, 1,2-naphthoquinone (1,2-NQ), may exert its genotoxic effects through interactions with cellular nucleophiles such as DNA, however, the mechanisms of 1,2-NQ adduct formation are still under investigation. With the aim to further understand these mechanisms, the chemical structures of adducts formed from the reaction of 2′-deoxyguanosine (dG) with 1,2-NQ under physiological conditions were investigated by liquid chromatography electrospray ionization tandem mass spectrometry and 1H NMR analyses. Results showed that 1,2-NQ underwent non-enzymatic oxidation to form a 1,2-NQ-epoxide which in turn formed at least four bulky adducts with dG, and these adducts were more likely to be formed under physiological conditions. A mechanism was proposed whereby hydration of 1,2-NQ to form unstable naphthohydroquinones and 2-hydroxy-1,4-naphthoquinone resulted in formation of hydrogen peroxide that oxidized 1,2-NQ. These results suggest that the genotoxicity of 1,2-NQ may not only be caused through oxidative DNA damage and adduct formation through Michael addition but also through non-enzymatic oxidative transformation of 1,2-NQ itself to form an intermediate PAH-epoxide which covalently binds to DNA.
ISSN:0893-228X
1520-5010
DOI:10.1021/acs.chemrestox.9b00088