Designer monotransregulators provide a basis for a transcriptional therapy for de novo endocrine-resistant breast cancer

Mol Med. 2010 Jan-Feb;16(1-2):10-8. doi: 10.2119/molmed.2009.00107. Epub 2009 Nov 17.

Abstract

The main circulating estrogen hormone 17beta-estradiol (E2) contributes to the initiation and progression of breast cancer. Estrogen receptors (ERs), as transcription factors, mediate the effects of E2. Ablation of the circulating E2 and/or prevention of ER functions constitute approaches for ER-positive breast cancer treatments. These modalities are, however, ineffective in de novo endocrine-resistant breast neoplasms that do not express ERs. The interaction of E2-ERs with specific DNA sequences, estrogen responsive elements (EREs), of genes constitutes one genomic pathway necessary for cellular alterations. We herein tested the prediction that specific regulation of ERE-driven genes by an engineered monomeric and constitutively active transcription factor, monotransregulator, provides a basis for the treatment of ER-negative breast cancer. Using adenovirus infected ER-negative MDA-MB-231 cells derived from a breast adenocarcinoma, we found that the monotransregulator, but not the ERE-binding defective counterpart, repressed cellular proliferation and motility, and induced apoptosis through expression of genes that required ERE interactions. Similarly, the monotransregulator suppressed the growth of ER-negative BT-549 cells derived from a breast-ductal carcinoma. Moreover, the ERE-binding monotransregulator repressed xenograft tumor growth in a nude mice model. Thus, specific regulation of genes bearing EREs could offer a therapeutic approach for de novo endocrine-resistant breast cancers.

Publication types

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

MeSH terms

  • Animals
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Breast Neoplasms / therapy*
  • Cell Death / physiology
  • Cell Growth Processes / physiology
  • Cell Line, Tumor
  • Cell Movement / physiology
  • Estradiol / metabolism
  • Estrogen Receptor alpha / genetics*
  • Estrogen Receptor alpha / metabolism
  • Female
  • Gene Expression Regulation, Neoplastic
  • Genes, Regulator
  • Genetic Therapy / methods
  • Humans
  • Mice
  • Mice, Nude
  • Response Elements*
  • Xenograft Model Antitumor Assays

Substances

  • Estrogen Receptor alpha
  • Estradiol