Cellular Biochemical Determinants Modulating the Metabolism of Estrone 3,4-Quinone

Louise M. Nutter, Bing Zhou, Esteban E. Sierra, Yu Ying Wu, Margaret M. Rummel, Peter Gutierrez, Yusuf J Abul-Hajj

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22 Scopus citations


The metabolism of the o-quinone derivative of estrone, 3,4-estrone quinone (3,4-EQ), has been investigated in human breast cancer cells. Unlike the p-quinone, diethylstilbestrol 4′,4″-quinone, 3,4-EQ was not a substrate for the two-electron reduction catalyzed by the putative detoxifying enzyme, NAD(P)H:quinone reductase (DT diaphorase; DT D). Accordingly, the DNA damage induced by 3,4-EQ in human MCF-7 cells was not affected by an inhibitor of DT D. Although 3,4-EQ was not an apparent substrate for the two-electron reduction catalyzed by DT D, this o-quinone was a substrate for the one-electron reduction catalyzed by cytochrome P450 reductase. The one-electron reduction of 3,4-EQ catalyzed by cytochrome P450 reductase occurred in the face of a significant and potentially physiologically relevant spontaneous reduction of 3,4-EQ by NADPH. The impact of purified superoxide dismutase (SOD) upon the production of hydrogen peroxide produced as a consequence of 3,4-EQ metabolism was evaluated; surprisingly, SOD inhibited the hydrogen peroxide produced by this o-quinone. Possible reasons for the SOD-mediated inhibition of redox cycling of 3,4-EQ are discussed. In summary, important differences in the metabolism of 3,4-EQ vis-a-vis o-and p-quinones have been observed, and the implications of these differences are discussed.

Original languageEnglish (US)
Pages (from-to)609-613
Number of pages5
JournalChemical research in toxicology
Issue number5
StatePublished - Sep 1 1994


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