Vascular endothelial growth factor receptor-2 expression is down-regulated by 17beta-estradiol in MCF-7 breast cancer cells by estrogen receptor alpha/Sp proteins

Mol Endocrinol. 2008 Feb;22(2):388-402. doi: 10.1210/me.2007-0319. Epub 2007 Nov 15.

Abstract

17beta-Estradiol (E2) induces and represses gene expression in breast cancer cells; however, the mechanisms of gene repression are not well understood. In this study, we show that E2 decreases vascular endothelial growth factor receptor 2 (VEGFR2) mRNA levels in MCF-7 cells, and this gene was used as a model for investigating pathways associated with E2-dependent gene repression. Deletion analysis of the VEGFR2 promoter indicates that the proximal GC-rich motifs at -58 and -44 are critical for the E2-dependent decreased response in MCF-7 cells. Mutation or deletion of these GC-rich elements results in loss of hormone responsiveness and shows that the -60 to -37 region of the VEGFR2 promoter is critical for both basal and hormone-dependent decreased VEGFR2 expression in MCF-7 cells. Western blot, immunofluorescent staining, RNA interference, and EMSAs support a role for Sp proteins in hormone-dependent down-regulation of VEGFR2 in MCF-7 cells, primarily through estrogen receptor (ER)alpha/Sp1 and ERalpha/Sp3 interactions with the VEGFR2 promoter. Using chromatin immuno-precipitation and transient transfection/RNA interference assays we show that the ERalpha/Sp protein-promoter interactions are accompanied by recruitment of the co-repressors SMRT (silencing mediator of retinoid and thyroid hormone receptor) and NCoR (nuclear receptor corepressor) to the promoter and that SMRT and NCoR knockdown reverse E2-mediated down-regulation of VEGFR2 expression in MCF-7 cells. This study illustrates that both SMRT and NCoR are involved in E2-dependent repression of VEGFR2 in MCF-7 cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Line, Tumor
  • Chromatin Immunoprecipitation
  • Electrophoretic Mobility Shift Assay
  • Estradiol / pharmacology*
  • Estrogen Receptor alpha / genetics
  • Estrogen Receptor alpha / metabolism
  • Estrogen Receptor alpha / physiology*
  • Fluorescent Antibody Technique
  • Gene Expression Regulation / drug effects
  • Humans
  • Models, Genetic
  • Promoter Regions, Genetic / genetics
  • Protein Binding
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sp Transcription Factors / genetics
  • Sp Transcription Factors / metabolism
  • Sp Transcription Factors / physiology*
  • Sp1 Transcription Factor / genetics
  • Sp1 Transcription Factor / metabolism
  • Sp1 Transcription Factor / physiology
  • Sp3 Transcription Factor / genetics
  • Sp3 Transcription Factor / metabolism
  • Sp3 Transcription Factor / physiology
  • Transfection
  • Vascular Endothelial Growth Factor Receptor-2 / genetics*

Substances

  • Estrogen Receptor alpha
  • RNA, Messenger
  • RNA, Small Interfering
  • Sp Transcription Factors
  • Sp1 Transcription Factor
  • Sp3 Transcription Factor
  • Estradiol
  • Vascular Endothelial Growth Factor Receptor-2