Epigenetic modulation of estrogen receptor-alpha by pRb family proteins: a novel mechanism in breast cancer

Cancer Res. 2007 Aug 15;67(16):7731-7. doi: 10.1158/0008-5472.CAN-07-1476.

Abstract

Estrogen receptor-alpha (ER-alpha) plays a crucial role in normal breast development and has also been linked to mammary carcinogenesis and clinical outcome in breast cancer patients. However, ER-alpha gene expression can change during the course of disease and, consequently, therapy resistance can occur. The molecular mechanism governing ER-alpha transcriptional activity and/or silencing is still unclear. Here, we showed that the presence of a specific pRb2/p130 multimolecular complex on the ER-alpha promoter strongly correlates with the methylation status of this gene. Furthermore, we suggested that pRb2/p130 could cooperate with ICBP90 (inverted CCAAT box binding protein of 90 kDa) and DNA methyltransferases in maintaining a specific methylation pattern of ER-alpha gene. The sequence of epigenetic events for establishing and maintaining the silenced state of ER-alpha gene can be locus- or pathway- specific, and the local remodeling of ER-alpha chromatin structure by pRb2/p130 multimolecular complexes may influence its susceptibility to specific DNA methylation. Our novel hypothesis could provide a basis for understanding how the complex pattern of ER-alpha methylation and transcriptional silencing is generated and for understanding the relationship between this pattern and its function during the neoplastic process.

Publication types

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

MeSH terms

  • Azacitidine / analogs & derivatives
  • Azacitidine / pharmacology
  • Breast Neoplasms / enzymology
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / metabolism
  • CCAAT-Enhancer-Binding Proteins / metabolism
  • Cell Line, Tumor
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases / metabolism
  • DNA Methylation
  • Decitabine
  • E1A-Associated p300 Protein / metabolism
  • Estrogen Receptor alpha / genetics*
  • Estrogen Receptor alpha / metabolism
  • Humans
  • Promoter Regions, Genetic
  • Retinoblastoma Protein / genetics*
  • Retinoblastoma Protein / metabolism
  • Retinoblastoma-Like Protein p107 / metabolism
  • Retinoblastoma-Like Protein p130 / genetics
  • Retinoblastoma-Like Protein p130 / metabolism
  • Ubiquitin-Protein Ligases

Substances

  • CCAAT-Enhancer-Binding Proteins
  • Estrogen Receptor alpha
  • Retinoblastoma Protein
  • Retinoblastoma-Like Protein p107
  • Retinoblastoma-Like Protein p130
  • Decitabine
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases
  • E1A-Associated p300 Protein
  • EP300 protein, human
  • UHRF1 protein, human
  • Ubiquitin-Protein Ligases
  • Azacitidine