ERalpha as ligand-independent activator of CDH-1 regulates determination and maintenance of epithelial morphology in breast cancer cells

Research output: Contribution to journalArticle

Authors

  • Maria Dafne Cardamone
  • Arantxa Gutierrez
  • Luciano Di Croce
  • Michael G Rosenfeld
  • Maria Flavia Di Renzo
  • Michele De Bortoli

Colleges, School and Institutes

External organisations

  • Department of Medicine, Howard Hughes Medical Institute, University of California at San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0651, USA.

Abstract

Estrogen receptor alpha (ERalpha) and E-cadherin are primary markers of luminal epithelial breast cancer cells with E-cadherin being a main caretaker of the epithelial phenotype. E-cadherin repression is needed for cancer cells to acquire motile and invasive properties, and it is known that in ER-positive breast cancer cells, estrogen down-regulate E-cadherin gene transcription. We report here that ERalpha is bound to the E-cadherin promoter in both the presence and the complete absence of estrogen, suggesting an unexpected role for unliganded ERalpha in E-cadherin transcription. Indeed, our data reveal that activation by unliganded ERalpha and repression by estrogen-activated ERalpha require direct binding to a half-estrogen response element within the E-cadherin promoter and exchange from associated coactivators to corepressors. Therefore, these results suggest a pivotal role for unliganded ERalpha in controlling a fundamental caretaker of the epithelial phenotype in breast cancer cells. Here, we show that ERalpha-positive breast cancer T47D cells transduced with the sfRON kinase undergo a full epithelial-mesenchymal conversion and lose E-cadherin and ERalpha expression. Our data show that, although the E-cadherin gene becomes hypermethylated and heterochromatic, kinase inhibitors can restore E-cadherin expression, together with an epithelial morphology in an ERalpha-dependent fashion. Similarly, transfection of ERalpha, in the absence of ligands, was sufficient to restore E-cadherin transcription in both sfRON-T47D and other ERalpha-, E-cadherin-negative cells. Therefore, our results suggest a novel role for the ERalpha that plays the dual role of ligand-independent activator and ligand-dependent repressor of E-cadherin in breast cancer cells.

Details

Original languageEnglish
Pages (from-to)7420-5
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number18
Publication statusPublished - 5 May 2009

Keywords

  • Amino Acid Sequence, Breast Neoplasms/genetics, Cadherins/genetics, Cell Line, Tumor, Epithelial Cells/metabolism, Estrogen Receptor alpha/metabolism, Gene Expression Regulation, Neoplastic, Humans, Ligands, Molecular Sequence Data, Promoter Regions, Genetic, Transcription, Genetic