Interference with the constitutive activation of ERK1 and ERK2 impairs EWS/FLI-1-dependent transformation

Oncogene. 2000 Sep 14;19(39):4523-30. doi: 10.1038/sj.onc.1203811.


The chimeric gene EWS/FLI-1, the hallmark of the Ewing's sarcoma and primitive neuroectodermal tumor family, encodes a fusion protein with enhanced transcriptional activation properties and preserved recognition of canonical ETS binding sites. Although EWS/FLI-1 alters the expression of various genes, the precise mechanism by which EWS/FLI-1 acts as an oncogene remains to be defined. In this study we report that members of the mitogen-activated protein kinase (MAPK) signaling pathway, ERK1 and ERK2, are constitutively activated in NIH 3T3 cells expressing EWS/FLI-1. Interference with ERK activation by either highly specific inhibitors of MEK1 or a dominant negative ras mutant profoundly impaired the ability of EWS/FLI-1 to transform NIH3T3 cells to growth in semi-solid medium. An EWS/FLI-1 mutant defective in DNA-binding and transcriptional activation failed to activate ERK and was also defective in 3T3 cell transformation. Constitutive ERK activation was also evident in several human Ewing's sarcoma tumor-derived cell lines. Interestingly, cells expressing the type II EWS/FLI-1 fusion, recently demonstrated more potent in transcriptional activation, showed even greater MAPK activation than cells expressing the more common type I fusion. These results implicate ERK activation in EWS/FLI-1 transformation and suggest that this signaling pathway may be important in the pathogenesis of Ewing's sarcoma. Oncogene (2000) 19, 4523 - 4530.

Publication types

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

MeSH terms

  • 3T3 Cells / pathology
  • Animals
  • Binding Sites
  • Bone Neoplasms / metabolism
  • Butadienes / pharmacology
  • Cell Transformation, Neoplastic*
  • Colony-Forming Units Assay
  • DNA / metabolism
  • Enzyme Activation
  • Enzyme Inhibitors / pharmacology
  • Flavonoids / pharmacology
  • Genes, ras
  • Humans
  • Imidazoles / pharmacology
  • MAP Kinase Kinase 1
  • Mice
  • Mitogen-Activated Protein Kinase 1 / metabolism*
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors
  • Mitogen-Activated Protein Kinases / metabolism*
  • Mutation
  • Nitriles / pharmacology
  • Oncogene Proteins, Fusion / genetics
  • Oncogene Proteins, Fusion / metabolism*
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Proto-Oncogene Protein c-fli-1
  • Pyridines / pharmacology
  • RNA-Binding Protein EWS
  • Sarcoma, Ewing / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Tumor Cells, Cultured


  • Butadienes
  • EWS-FLI fusion protein
  • Enzyme Inhibitors
  • Flavonoids
  • Imidazoles
  • Nitriles
  • Oncogene Proteins, Fusion
  • Proto-Oncogene Protein c-fli-1
  • Pyridines
  • RNA-Binding Protein EWS
  • Transcription Factors
  • U 0126
  • DNA
  • Protein-Serine-Threonine Kinases
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 1
  • MAP2K1 protein, human
  • Map2k1 protein, mouse
  • Mitogen-Activated Protein Kinase Kinases
  • SB 203580
  • 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one