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Updated: Mar 27, 2026

Mapping the Structure-Function Relationships of Disordered Oncogenic Transcription Factors Using Transcriptomic Analysis
Published on: June 27, 2020
Functional Genomic Screening Reveals Splicing of the EWS-FLI1 Fusion Transcript as a Vulnerability in Ewing Sarcoma
Patrick J Grohar1, Suntae Kim2, Guillermo O Rangel Rivera3
1Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Abstract:
Ewing sarcoma cells depend on the EWS-FLI1 fusion transcription factor for cell survival. Using an assay of EWS-FLI1 activity and genome-wide RNAi screening, we have identified proteins required for the processing of the EWS-FLI1 pre-mRNA. We show that Ewing sarcoma cells harboring a genomic breakpoint that retains exon 8 of EWSR1 require the RNA-binding protein HNRNPH1 to express in-frame EWS-FLI1. We also demonstrate the sensitivity of EWS-FLI1 fusion transcripts to the loss of function of the U2 snRNP component, SF3B1. Disrupted splicing of the EWS-FLI1 transcript alters EWS-FLI1 protein expression and EWS-FLI1-driven expression. Our results show that the processing of the EWS-FLI1 fusion RNA is a potentially targetable vulnerability in Ewing sarcoma cells.

