DNA-binding ability of NF-kappaB is affected differently by ERalpha and ERbeta and its activation results in inhibition of estrogen responsiveness

Reprod Sci. 2008 May;15(5):493-505. doi: 10.1177/1933719108317583.

Abstract

Estrogenic effects involve interactions between estrogen receptors (ERs), response elements, and nuclear proteins. It is hypothesized that interaction between ER and NF-kappa B may affect the regulation of responsive genes. Electrophoretic mobility shift assay (EMSA) was performed to assess if the interaction of ERs and NF- kappaB affect their respective DNA-binding activities, and alkaline phosphatase assay was done to evaluate estrogenic activity. EMSA revealed that ERs inhibit DNA-binding of p50 and p65, whereas p50 did not impair ER alpha binding. Stimulation with estradiol inhibited DNA binding of NF-kappaB in ERalpha-transfected endometrial stromal cells (ESCs). Moreover, activation of NF-kappaB significantly decreased estrogen responsiveness of Ishikawa cells and ERalpha-transfected ESC. Our results suggest that ERs downregulate NF-kappaB-dependent gene activation by directly preventing DNA binding. However, NF-kappaB-mediated inhibition of ER-dependent gene activation may be carried out indirectly rather than through a direct inhibition of ER-DNA binding. These findings offer new insight into the specific role of ERalpha and could eventually help in developing therapeutics for endometriosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Binding, Competitive
  • Cell Line
  • DNA / metabolism*
  • Endometriosis / metabolism*
  • Estradiol / pharmacology*
  • Estrogen Receptor alpha / metabolism*
  • Estrogen Receptor beta / metabolism*
  • Female
  • Humans
  • Jurkat Cells
  • NF-kappa B / metabolism*
  • U937 Cells

Substances

  • Estrogen Receptor alpha
  • Estrogen Receptor beta
  • NF-kappa B
  • Estradiol
  • DNA