Abstract
A growing number of studies indicate that breast cancer initiation is related to abnormal estrogen oxidation to form an excess of estrogen-3,4-quinones, which react with DNA to form depurinating adducts and induce mutations. This mechanism is often called estrogen genotoxicity. 4-Catechol estrogens, precursors of the estrogen-3,4-quinones, were previously shown to account for most of the transforming and tumorigenic activity. We examined whether estrogen-induced transformation can be reduced by inhibiting the oxidation of a 4-catechol estrogen to its quinone. We demonstrate that E6 cells (a normal mouse epithelial cell line) can be transformed by a single treatment with a catechol estrogen or its quinone. The transforming activities of 4-hydroxyestradiol and estradiol-3,4-quinone were comparable. N-Acetylcysteine, a common antioxidant, inhibited the oxidation of 4-hydroxyestradiol to the quinone and consequent formation of DNA adducts. It also drastically reduced estrogen-induced transformation of E6 cells. These results strongly implicate estrogen genotoxicity in mammary cell transformation. Since N-acetylcysteine is well tolerated in clinical studies, it may be a promising candidate for breast cancer prevention.
Original language | English (US) |
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Pages (from-to) | 22-30 |
Number of pages | 9 |
Journal | Journal of Steroid Biochemistry and Molecular Biology |
Volume | 109 |
Issue number | 1-2 |
DOIs | |
State | Published - Mar 2008 |
Keywords
- Catechol estrogen quinone
- Mammary epithelial cells
- N-acetylcysteine
- Transformation
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Biochemistry
- Molecular Medicine
- Molecular Biology
- Endocrinology
- Clinical Biochemistry
- Cell Biology