Interference with the constitutive activation of ERK1 and ERK2 impairs EWS/FLI-1-dependent transformation.
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.
Silvany
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RE
Division of Hematology/Oncology, Department of Medicine, Simmons Cancer Center and the Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Eliazer
S
S
Wolff
N C
NC
Ilaria
R L
RL
D016475:3T3 Cells / Q000473:pathology; D000818:Animals; D001665:Binding Sites; D001859:Bone Neoplasms / Q000378:metabolism; D002070:Butadienes / Q000494:pharmacology; D002471:Cell Transformation, Neoplastic; D003114:Colony-Forming Units Assay; D004247:DNA / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D011905:Genes, ras; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D048369:MAP Kinase Kinase 1; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009154:Mutation; D009570:Nitriles / Q000494:pharmacology; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D051789:Proto-Oncogene Protein c-fli-1; D011725:Pyridines / Q000494:pharmacology; D034802:RNA-Binding Protein EWS; D012512:Sarcoma, Ewing / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D002070:Butadienes; C106031:EWS-FLI fusion protein; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D009570:Nitriles; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D011725:Pyridines; D034802:RNA-Binding Protein EWS; D014157:Transcription Factors; C113580:U 0126; D004247:DNA; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; C482127:Map2k1 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one