Critical role of the fibroblast growth factor signalling pathway in Ewing's sarcoma octamer-binding transcription factor 4-mediated cell proliferation and tumorigenesis

FEBS J. 2019 Nov;286(22):4443-4472. doi: 10.1111/febs.14946. Epub 2019 Jun 12.


Certain bone and soft tissue (BST) tumours harbour a chromosomal translocation [t(6;22)(p21;q12)], which fuses the Ewing's sarcoma (EWS) gene at 22q12 with the octamer-binding transcription factor 4 (Oct-4) gene at 6p21, resulting in the chimeric EWS-Oct-4 protein that possesses high transactivation ability. Although abnormal activation of signalling pathways can lead to human cancer development, the pathways underlying these processes in human BST tumours remain poorly explored. Here, we investigated the functional significance of fibroblast growth factor (FGF) signalling in human BST tumours. To identify the gene(s) involved in the FGF signalling pathway and potentially regulated by EWS-Oct-4 (also called EWS-POU5F1), we performed RNA-Seq analysis, electrophoretic mobility shift assays, chromatin immunoprecipitation assays, and xenograft assays. Treating GBS6 or ZHBTc4 cells-expressing EWS-Oct-4 with the small molecule FGF receptor (FGFR) inhibitors PD173074, NVPBGJ398, ponatinib, and dovitinib suppressed cellular proliferation. Gene expression analysis revealed that, among 22 Fgf and four Fgfr family members, Fgf-4 showed the highest upregulation (by 145-fold) in ZHBTc4 cells-expressing EWS-Oct-4. Computer-assisted analysis identified a putative EWS-Oct-4-binding site at +3017/+3024, suggesting that EWS-Oct-4 regulates Fgf-4 expression in human BST tumours. Fgf-4 enhancer constructs showed that EWS-Oct-4 transactivated the Fgf-4 gene reporter in vitro, and that overexpression of EWS-Oct-4 stimulated endogenous Fgf-4 gene expression in vivo. Finally, PD173074 significantly decreased tumour volume in mice. Taken together, these data suggest that FGF-4 signalling is involved in EWS-Oct-4-mediated tumorigenesis, and that its inhibition impairs tumour growth in vivo significantly.

Keywords: EWS-Oct-4; FGF signalling; chromosomal translocation; fusion protein; human bone and soft tissue tumour.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Benzimidazoles / pharmacology
  • Binding Sites
  • Carcinogenesis / genetics
  • Carcinogenesis / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation*
  • Fibroblast Growth Factor 4 / genetics
  • Fibroblast Growth Factor 4 / metabolism*
  • Humans
  • Imidazoles / pharmacology
  • Mice
  • Octamer Transcription Factor-3 / genetics*
  • Octamer Transcription Factor-3 / metabolism
  • Oncogene Proteins, Fusion / chemistry
  • Oncogene Proteins, Fusion / genetics
  • Oncogene Proteins, Fusion / metabolism*
  • Protein Binding
  • Pyridazines / pharmacology
  • Pyrimidines / pharmacology
  • Quinolones / pharmacology
  • Receptors, Fibroblast Growth Factor / antagonists & inhibitors
  • Signal Transduction*
  • Soft Tissue Neoplasms / genetics
  • Soft Tissue Neoplasms / metabolism*


  • 4-amino-5-fluoro-3-(5-(4-methylpiperazin-1-yl)-1H-benzimidazol-2-yl)quinolin-2(1H)-one
  • Benzimidazoles
  • FGF4 protein, human
  • Fibroblast Growth Factor 4
  • Imidazoles
  • Octamer Transcription Factor-3
  • Oncogene Proteins, Fusion
  • PD 173074
  • POU5F1 protein, human
  • Pyridazines
  • Pyrimidines
  • Quinolones
  • Receptors, Fibroblast Growth Factor
  • ponatinib