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Open Access CC BY V4.0
Journal article
Targeting of the oncogenic fusion EWSR1-FLI1 in Ewing Sarcoma by CRISPR/dCas9 silencers
Molecular Therapy, In Press
2026
Abstract
Despite the revolutionary impact of genome engineering tools in medicine, the safe and effective intracellular delivery of CRISPR remains a major obstacle for clinical applications. Here, we utilize precision molecular targeting and delivery strategies based on CRISPR/dCas9 systems adapted for epigenetic repression (dCas9-KRAB) to silence oncogenic drivers with high selectivity. As proof-of-principle, we target the EWSR1-FLI1 translocation, which encodes a chimeric and hard-to-drug oncogenic transcription factor driving approximately 85% of the cases of Ewing Sarcoma (EWS)-an aggressive childhood malignancy. We describe the development of a programmable non-viral polymeric system for the delivery of dCas9-KRAB as ribonucleoprotein (RNP) payloads for EWSR1-FLI1 repression. We demonstrate highly efficient intracellular delivery of RNPs loaded in polyamide-amine (PAMAM) polymers functionalized by guanidino groups, resulting in robust silencing of EWSR1-FLI1 both in established cell line xenografts and in EWS-related patient-derived xenografts (PDXs) of EWS. We show that silencing of EWSR1–FLI1 is accompanied by potent anti-tumor effects. Collectively, we characterize an effective non-viral platform for in vivo delivery of dCas9-KRAB/RNPs, which could be adapted for the repression of any oncogene. We further outline dCas9/RNP formulations for future therapeutic applications to treat poor-prognosis cancers driven by hard-to-drug oncogenes.
Details
- Title
- Targeting of the oncogenic fusion EWSR1-FLI1 in Ewing Sarcoma by CRISPR/dCas9 silencers
- Authors/Creators
- S. Taifour - Harry Perkins Institute of Medical ResearchChee-Wai WongChristopher WallisEdina WangAsh W.J. TieEleanor WoodwardCharlene WaryahMahnaz HosseinpourDilys LamRyan ListerLarissa DymondAndrew Woo - Murdoch University, School of Medical, Molecular and Forensic SciencesPeter J. HoughtonK. Swaminathan IyerMarck Norret - The University of Western AustraliaCameron W. EvansLouise WinteringhamSilvana Gaudieri - Vanderbilt University Medical CenterPilar Blancafort
- Publication Details
- Molecular Therapy, In Press
- Publisher
- Elsevier Inc. on behalf of The American Society of Gene and Cell Therapy.
- Identifiers
- 991005909767707891
- Copyright
- © 2026 The Authors.
- Murdoch Affiliation
- School of Medical, Molecular and Forensic Sciences; Institute for Immunology and Infectious Diseases
- Resource Type
- Journal article
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