Abstract
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
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3T3 Cells / pathology
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Animals
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Binding Sites
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Bone Neoplasms / metabolism
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Butadienes / pharmacology
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Cell Transformation, Neoplastic*
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Colony-Forming Units Assay
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DNA / metabolism
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Enzyme Activation
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Enzyme Inhibitors / pharmacology
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Flavonoids / pharmacology
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Genes, ras
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Humans
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Imidazoles / pharmacology
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MAP Kinase Kinase 1
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Mice
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Mitogen-Activated Protein Kinase 1 / metabolism*
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors
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Mitogen-Activated Protein Kinases / metabolism*
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Mutation
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Nitriles / pharmacology
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Oncogene Proteins, Fusion / genetics
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Oncogene Proteins, Fusion / metabolism*
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Protein Serine-Threonine Kinases / antagonists & inhibitors
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Proto-Oncogene Protein c-fli-1
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Pyridines / pharmacology
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RNA-Binding Protein EWS
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Sarcoma, Ewing / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Tumor Cells, Cultured
Substances
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Butadienes
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EWS-FLI fusion protein
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Enzyme Inhibitors
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Flavonoids
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Imidazoles
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Nitriles
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Oncogene Proteins, Fusion
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Proto-Oncogene Protein c-fli-1
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Pyridines
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RNA-Binding Protein EWS
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Transcription Factors
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U 0126
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DNA
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Protein Serine-Threonine Kinases
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinases
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MAP Kinase Kinase 1
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MAP2K1 protein, human
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Map2k1 protein, mouse
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Mitogen-Activated Protein Kinase Kinases
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SB 203580
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2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one