Human EWS-FLI protein recapitulates in Drosophila the neomorphic functions that induce Ewing sarcoma tumorigenesis

Cristina Molnar; Jose Reina; Anastasia Herrero; Jan Peter Heinen; Victoria Méndiz; Sophie Bonnal; Manuel Irimia; María Sánchez-Jiménez; Sara Sánchez-Molina; Jaume Mora; Cayetano Gonzalez

doi:10.1093/pnasnexus/pgac222

Human EWS-FLI protein recapitulates in Drosophila the neomorphic functions that induce Ewing sarcoma tumorigenesis

PNAS Nexus. 2022 Oct 6;1(4):pgac222. doi: 10.1093/pnasnexus/pgac222. eCollection 2022 Sep.

Authors

Cristina Molnar¹, Jose Reina¹, Anastasia Herrero^{1

2}, Jan Peter Heinen¹, Victoria Méndiz¹, Sophie Bonnal^{3

4}, Manuel Irimia^{3

4

5}, María Sánchez-Jiménez^{2

6}, Sara Sánchez-Molina^{2

6}, Jaume Mora^{2

6}, Cayetano Gonzalez^{1

5}

Affiliations

¹ Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Carrer Baldiri Reixac 10, 08028 Barcelona, Spain.
² Developmental Tumor Biology Laboratory, Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat 08950 Barcelona, Spain.
³ Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.
⁴ Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain.
⁵ Institucio Catalana de Recerca i Estudis Avançats (ICREA), Pg Lluis Companys 23, 08010 Barcelona, Spain.
⁶ Pediatric Cancer Center Barcelona (PCCB), Hospital Sant Joan de Déu, Esplugues de Llobregat, 08950 Barcelona, Spain.

Abstract

Ewing sarcoma (EwS) is a human malignant tumor typically driven by the Ewing sarcoma-Friend leukemia integration (EWS-FLI) fusion protein. A paucity of genetically modified animal models, partially owed to the high toxicity of EWS-FLI, hinders research on EwS. Here, we report a spontaneous mutant variant, EWS-FLI_1FS, that circumvents the toxicity issue in Drosophila. Through proteomic and genomic analyses, we show that human EWS-FLI_1FS interacts with the Drosophila homologues of EWS-FLI human protein partners, including core subunits of chromatin remodeling complexes, the transcription machinery, and the spliceosome; brings about a massive dysregulation of transcription that affects a significant fraction of known targets of EWS-FLI in human cells; and modulates splicing. We also show that EWS-FLI_1FS performs in Drosophila the two major neomorphic activities that it is known to have in human cells: activation of transcription from GGAA microsatellites and out competition of ETS transcription factors. We conclude that EWS-FLI_1FS reproduces in Drosophila the known oncogenic activities of EWS-FLI that drive EwS tumorigenesis in humans. These results open up an unprecedented opportunity to investigate EWS-FLI's oncogenic pathways in vivo in a genetically tractable organism.