Transformation induced by Ewing's sarcoma associated EWS/FLI-1 is suppressed by KRAB/FLI-1

Br J Cancer. 2003 Jan 13;88(1):137-45. doi: 10.1038/sj.bjc.6600669.

Abstract

Ewing's sarcoma is a childhood bone tumour with poor prognosis, most commonly associated with a t(11;22)(q24;q12) reciprocal translocation that fuses the EWS and FLI-1 genes, resulting in the production of an aberrant chimeric transcription factor EWS/FLI-1. To elucidate the mechanisms by which EWS/FLI-1 mediates transformation in mouse models, we have generated a murine Ews/Fli-1 fusion protein. We demonstrate that this protein transforms fibroblast cells in vitro similar to human EWS/FLI-1 as demonstrated by serum and anchorage-independent growth, the formation of tumours in nude mice and elevation of the oncogenic marker c-myc. Furthermore, transformation of these cells was inhibited by a specific repressor, KRAB/FLI-1. The KRAB/FLI-1 repressor also suppressed the tumorigenic phenotype of a human Ewing's sarcoma cell line. These findings suggest that the transformed phenotype of Ewing's sarcoma cells can be reversed by using the sequence-specific FLI-1-DNA-binding domain to target a gene repressor domain. The inhibition of EWS/FLI-1 is the first demonstration of the KRAB domain suppressing the action of an ETS factor. This approach provides potential avenues for the elucidation of the biological mechanisms of EWS/FLI-1 oncogenesis and the development of novel therapeutic strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Animals
  • Cell Division / drug effects
  • Cell Transformation, Neoplastic / chemically induced*
  • Colony-Forming Units Assay
  • Culture Media
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / pharmacology*
  • Genes, Suppressor / physiology
  • Mice
  • Phenotype
  • Protein Structure, Tertiary
  • Proto-Oncogene Protein c-fli-1
  • Proto-Oncogene Proteins*
  • RNA-Binding Protein EWS / genetics
  • RNA-Binding Protein EWS / pharmacology*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / pharmacology
  • Repressor Proteins*
  • Sarcoma, Ewing / chemistry*
  • Trans-Activators / biosynthesis
  • Trans-Activators / genetics
  • Trans-Activators / pharmacology*

Substances

  • Culture Media
  • DNA-Binding Proteins
  • Fli1 protein, mouse
  • Proto-Oncogene Protein c-fli-1
  • Proto-Oncogene Proteins
  • RNA-Binding Protein EWS
  • Recombinant Fusion Proteins
  • Repressor Proteins
  • Trans-Activators
  • ZNF350 protein, human