SIX1 and EWS/FLI1 co-regulate an anti-metastatic gene network in Ewing Sarcoma

Nat Commun. 2023 Jul 19;14(1):4357. doi: 10.1038/s41467-023-39945-w.


Ewing sarcoma (ES), which is characterized by the presence of oncogenic fusion proteins such as EWS/FLI1, is an aggressive pediatric malignancy with a high rate of early dissemination and poor outcome after distant spread. Here we demonstrate that the SIX1 homeoprotein, which enhances metastasis in most tumor types, suppresses ES metastasis by co-regulating EWS/FLI1 target genes. Like EWS/FLI1, SIX1 promotes cell growth/transformation, yet dramatically inhibits migration and invasion, as well as metastasis in vivo. We show that EWS/FLI1 promotes SIX1 protein expression, and that the two proteins share genome-wide binding profiles and transcriptional regulatory targets, including many metastasis-associated genes such as integrins, which they co-regulate. We further show that SIX1 downregulation of integrins is critical to its ability to inhibit invasion, a key characteristic of metastatic cells. These data demonstrate an unexpected anti-metastatic function for SIX1, through coordinate gene regulation with the key oncoprotein in ES, EWS/FLI1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Child
  • Gene Expression Regulation
  • Gene Expression Regulation, Neoplastic
  • Gene Regulatory Networks
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Humans
  • Integrins / metabolism
  • Oncogene Proteins, Fusion / genetics
  • Oncogene Proteins, Fusion / metabolism
  • Proto-Oncogene Protein c-fli-1 / genetics
  • Proto-Oncogene Protein c-fli-1 / metabolism
  • RNA-Binding Protein EWS / genetics
  • Sarcoma, Ewing* / pathology


  • Proto-Oncogene Protein c-fli-1
  • RNA-Binding Protein EWS
  • Oncogene Proteins, Fusion
  • Integrins
  • SIX1 protein, human
  • Homeodomain Proteins