p300/CBP is an essential driver of pathogenic enhancer activity and gene expression in Ewing sarcoma.

Publication Type Academic Article
Authors Godfrey L, Regalado B, Schweber S, Hatton C, Wenge D, Wen Y, Boileau M, Wessels M, Qi J, Ott C, Stegmaier K, Rivera M, Armstrong S
Journal EMBO Rep
Volume 26
Issue 19
Pagination 4766-4793
Date Published 09/01/2025
ISSN 1469-3178
Keywords Sarcoma, Ewing, Enhancer Elements, Genetic, p300-CBP Transcription Factors, RNA-Binding Protein EWS, Gene Expression Regulation, Neoplastic, Bone Neoplasms, E1A-Associated p300 Protein
Abstract The t(11;22) translocation encodes the EWS::FLI1 fusion oncoprotein which is the primary driver of Ewing sarcoma. EWS::FLI1 creates unique, de novo pathogenic enhancers that drive gene expression and are a central mechanism of oncogenesis. Which chromatin regulatory proteins are critical to this mechanism is understudied. Here, we perform a comparative analysis of the function of the chromatin complexes MLL3/4 and p300/CBP in EWS::FLI1-mediated gene regulation. Using EWS::FLI1 degradation models, we define a subset of EWS::FLI1-sensitive enhancers whose activity correlates with p300/CBP function. We perturb both chromatin complexes to establish that in contrast to MLL3/4, p300/CBP is a critical regulator of EWS::FLI1-driven enhancer activity and downstream gene expression. We also show that p300/CBP small-molecule inhibition decelerates tumor growth in vivo. Our work highlights the context-dependent nature of chromatin protein activity at oncogenic enhancers and reveals p300/CBP as an important regulator of Ewing sarcoma.
DOI 10.1038/s44319-025-00552-z
PubMed ID 40890402
PubMed Central ID PMC12508431
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