EZH2 promotes expansion of breast tumor initiating cells through activation of RAF1-β-catenin signaling

Cancer Cell. 2011 Jan 18;19(1):86-100. doi: 10.1016/j.ccr.2010.10.035. Epub 2011 Jan 6.

Abstract

It has been proposed that an aggressive secondary cancer stem cell population arises from a primary cancer stem cell population through acquisition of additional genetic mutations and drives cancer progression. Overexpression of Polycomb protein EZH2, essential in stem cell self-renewal, has been linked to breast cancer progression. However, critical mechanism linking increased EZH2 expression to BTIC (breast tumor initiating cell) regulation and cancer progression remains unclear. Here, we identify a mechanism in which EZH2 expression-mediated downregulation of DNA damage repair leads to accumulation of recurrent RAF1 gene amplification in BTICs, which activates p-ERK-β-catenin signaling to promote BTIC expansion. We further reveal that AZD6244, a clinical trial drug that inhibits RAF1-ERK signaling, could prevent breast cancer progression by eliminating BTICs.

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

  • Animals
  • Benzenesulfonates / pharmacology
  • Benzimidazoles / pharmacology
  • Benzimidazoles / therapeutic use
  • Breast Neoplasms / diagnosis
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology*
  • Cell Hypoxia / physiology
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Centrosome / pathology
  • Chromosome Aberrations
  • DNA Breaks, Double-Stranded
  • DNA Damage / genetics
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Enhancer of Zeste Homolog 2 Protein
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Female
  • Gene Expression / drug effects
  • Gene Expression / genetics
  • Gene Expression Regulation, Neoplastic / physiology
  • Humans
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Models, Biological
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / metabolism
  • Neoplastic Stem Cells / pathology*
  • Niacinamide / analogs & derivatives
  • Phenylurea Compounds
  • Phosphorylation / drug effects
  • Polycomb Repressive Complex 2
  • Proto-Oncogene Proteins c-raf / genetics
  • Proto-Oncogene Proteins c-raf / metabolism*
  • Pyridines / pharmacology
  • Rad51 Recombinase / genetics
  • Rad51 Recombinase / metabolism
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*
  • Sorafenib
  • Spheroids, Cellular / drug effects
  • Spheroids, Cellular / pathology
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transplantation, Heterologous / pathology
  • Xenograft Model Antitumor Assays
  • beta Catenin / metabolism*

Substances

  • AZD 6244
  • Benzenesulfonates
  • Benzimidazoles
  • CTNNB1 protein, human
  • DNA-Binding Proteins
  • Phenylurea Compounds
  • Pyridines
  • Transcription Factors
  • beta Catenin
  • Niacinamide
  • Sorafenib
  • EZH2 protein, human
  • Enhancer of Zeste Homolog 2 Protein
  • Polycomb Repressive Complex 2
  • Proto-Oncogene Proteins c-raf
  • Extracellular Signal-Regulated MAP Kinases
  • RAD51 protein, human
  • Rad51 Recombinase

Associated data

  • GEO/GSE224144