Estrogens as endogenous genotoxic agents--DNA adducts and mutations.
Level 5 - mechanism / opinion, no new human data
Narrative review of mechanistic bench, in vitro, and animal research.
PubMed 10963621 · doi:10.1093/oxfordjournals.jncimonographs.a024247
What was done
This review examined the biochemical and molecular pathways through which estrogens induce genotoxicity. It evaluated the formation of DNA adducts by reactive electrophilic estrogen metabolites (specifically catechol estrogen quinones), the generation of reactive oxygen species and subsequent indirect oxidative DNA damage, and the induction of numerical and structural chromosomal mutations and gene mutations in cell cultures and animal models.
What was found
The abstract reports qualitative mechanistic pathways without quantitative numerical data. Quinones derived from the catechol estrogens 4-hydroxyestradiol and 4-hydroxyestrone react with purine bases to form depurinating DNA adducts that generate mutagenic apurinic sites, whereas 2-hydroxyestrogen quinones yield stable DNA adducts. Metabolic redox cycling of catechol estrogens generates reactive oxygen radicals that cause base oxidation, DNA strand breakage, and lipid peroxidation-derived adducts. Both natural estradiol and synthetic diethylstilbestrol induce structural and numerical chromosomal aberrations as well as gene mutations.
Why it matters
This review highlights that endogenous and synthetic estrogens can act as direct and indirect genotoxic carcinogens via reactive chemical metabolites, complementing their established receptor-mediated proliferative effects.
Limits
The abstract describes a narrative review with no systematic search methodology, meta-analysis, or primary human clinical data. Quantitative dose-response relationships and specific numbers are not provided, and mechanistic findings rely heavily on in vitro and animal models.
Cited by
- supports The estrogen metabolite 4-hydroxyestrone can form DNA adducts and is genotoxic.