title: ETV6-NTRK3 transformation requires insulin-like growth factor 1 receptor signaling and is associated with constitutive IRS-1 tyrosine phosphorylation.
abstract: Congenital fibrosarcoma (CFS) and cellular mesoblastic nephroma (CMN) are pediatric spindle cell malignancies that share two specific cytogenetic abnormalities: trisomy of chromosome 11 and a t(12;15)(p13;q25) translocation. The t(12;15) rearrangement creates a transcriptionally active fusion gene that encodes a chimeric oncoprotein, ETV6-NTRK3 (EN). EN transforms NIH3T3 fibroblasts through constitutive activation of both the Ras-mitogen-activated protein kinase (MAPK) pathway and the phosphatidylinositol-3'kinase (PI3K)-Akt pathway. However, the role of trisomy 11 in CFS and CMN remains unknown. In this study we demonstrate elevated expression of the chromosome 11p15.5 insulin-like growth factor 2 gene (IGF2) in CFS and CMN tumors. Moreover, we present evidence that an intact IGF signaling axis is essential for in vitro EN-mediated transformation. EN only very weakly transformed so-called R-murine fibroblasts derived from mice with a targeted disruption of the IGF1 receptor gene (IGFRI), but transformation activity was fully restored in R- cells engineered to re-express IGFRI (R+ cells). We also observed that the major IGFRI substrate, insulin-receptor substrate-1 (IRS-1), was constitutively tyrosine phosphorylated and could be co-immunoprecipitated with EN in either R- or R+ cells expressing the EN oncoprotein. IRS-1 association with Grb2 and PI3K p85, which link IGFRI to the Ras-MAPK and PI3K-Akt pathways, respectively, was enhanced in both cell types in the presence of EN. However, activation of the Ras-MAPK and PI3K-Akt pathways was markedly attenuated in EN-expressing R- cells compared to EN-transformed R+ cells. This suggests that IRS-1 may be functioning as an adaptor in EN signal transduction, but that a link to EN transformation pathways requires the presence of IGFRI. Our findings indicate that an intact IGF signaling axis is essential for EN transformation, and are consistent with a role for trisomy 11 in augmenting this pathway in EN expressing tumors.
authors.affiliation: Department of Pathology, BC Research Institute for Children's and Women's Health, and the University of British Columbia, Vancouver, BC V5Z 4H4, Canada.
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Morrison
authors.forename: Cristina E
authors.initials: CE
authors.lastname: Tognon
authors.forename: Mathew J
authors.initials: MJ
authors.lastname: Garnett
authors.forename: Cheri
authors.initials: C
authors.lastname: Deal
authors.forename: Poul H B
authors.initials: PH
authors.lastname: Sorensen
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002471:Cell Transformation, Neoplastic; D004268:DNA-Binding Proteins / Q000502:physiology*; D051380:GRB2 Adaptor Protein; D055504:Insulin Receptor Substrate Proteins; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011506:Proteins / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D050783:Proto-Oncogene Proteins c-ets; D017526:Receptor, IGF Type 1 / Q000502:physiology*; D020812:Receptor, trkC / Q000502:physiology*; D012097:Repressor Proteins / Q000502:physiology*; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism; D000097764:ETS Translocation Variant 6 Protein
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D051380:GRB2 Adaptor Protein; D055504:Insulin Receptor Substrate Proteins; D007335:Insulin-Like Growth Factor II; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011506:Proteins; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D050783:Proto-Oncogene Proteins c-ets; D017526:Receptor, IGF Type 1; D020812:Receptor, trkC; D012097:Repressor Proteins; D014443:Tyrosine; D000097764:ETS Translocation Variant 6 Protein; C495949:Grb2 protein, mouse; C526295:Irs1 protein, mouse; C482127:Map2k1 protein, mouse