Repression of cancer protective genes by 17β-estradiol: Ligand-dependent interaction between human Nrf2 and estrogen receptor α

P. J. Ansell, S. C. Lo, L. G. Newton, C. Espinosa-Nicholas, D. D. Zhang, J. H. Liu, M. Hannink, D. B. Lubahn

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

Repression of cancer-protective phase II enzymes may help explain why estrogen exposure leads to the development of cancer. In an earlier report we described the ability of 17β-estradiol (E2) to repress phase II enzyme activity in vivo. Phase II enzymes are coordinately regulated via the presence of the antioxidant response element (ARE) in their promoter. We wanted to determine if estrogen receptors (ER) repress ARE-dependent gene expression through a mechanism that requires interaction with Nrf2, the transcription factor that regulates ARE-mediated gene transcription. E2-bound ERα, but not ERβ, represses ARE-regulated gene expression in the presence of exogenously expressed Nrf2 as well as when the transactivation domain of Nrf2 was fused to a heterologous DNA-binding domain. Deletion of the activation function-2 (AF-2) and the ligand-binding domain of ERα result in a constitutive repression of Nrf2-mediated transcription. Finally, E 2-bound ERα co-immunoprecipitates with Nrf2. Repression of Nrf2-mediated transcription by E2-bound ERα expands our knowledge of E2-regulated genes and provides a potential drug-screening target for the development of selective estrogen receptor modulators with a lower risk of causing cancer.

Original languageEnglish (US)
Pages (from-to)27-34
Number of pages8
JournalMolecular and Cellular Endocrinology
Volume243
Issue number1-2
DOIs
StatePublished - Nov 24 2005
Externally publishedYes

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Keywords

  • Antioxidant response element
  • Estrogen receptor
  • Estrogens
  • Nrf2
  • Oxidative stress
  • Phase II detoxification enzymes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology

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