Genome-scale CRISPR-Cas9 screen identifies druggable dependencies in TP53 wild-type Ewing sarcoma

  • J Exp Med. 2018 Aug 6;215(8):2137-2155. doi: 10.1084/jem.20171066.
Björn Stolte  1  2  3 ,  Amanda Balboni Iniguez  1  3 ,  Neekesh V Dharia  1  3 ,  Amanda L Robichaud  1 ,  Amy Saur Conway  1 ,  Ann M Morgan  4 ,  Gabriela Alexe  1  3  5 ,  Nathan J Schauer  6  7 ,  Xiaoxi Liu  6  7 ,  Gregory H Bird  4 ,  Aviad Tsherniak  3 ,  Francisca Vazquez  3 ,  Sara J Buhrlage  6  7 ,  Loren D Walensky  8 ,  Kimberly Stegmaier  9  3
Affiliations
  • 1. Department of Pediatric Oncology, Dana-Farber Cancer Institute and Boston Children's Hospital, Harvard Medical School, Boston, MA.
  • 2. Dr. von Hauner Children's Hospital, Department of Pediatrics, University Hospital, LMU Munich, Munich, Germany.
  • 3. The Broad Institute of MIT and Harvard, Cambridge, MA.
  • 4. Department of Pediatric Oncology and the Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA.
  • 5. Bioinformatics Graduate Program, Boston University, Boston, MA.
  • 6. Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA.
  • 7. Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA.
  • 8. Department of Pediatric Oncology and the Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA [email protected].
  • 9. Department of Pediatric Oncology, Dana-Farber Cancer Institute and Boston Children's Hospital, Harvard Medical School, Boston, MA [email protected].
PMID: 30045945 DOI: 10.1084/jem.20171066
Abstract

Ewing sarcoma is a pediatric Cancer driven by EWS-ETS transcription factor fusion oncoproteins in an otherwise stable genomic background. The majority of tumors express wild-type TP53, and thus, therapies targeting the p53 pathway would benefit most patients. To discover targets specific for TP53 wild-type Ewing sarcoma, we used a genome-scale CRISPR-Cas9 screening approach and identified and validated MDM2, MDM4, USP7, and PPM1D as druggable dependencies. The stapled peptide inhibitor of MDM2 and MDM4, ATSP-7041, showed anti-tumor efficacy in vitro and in multiple mouse models. The USP7 Inhibitor, P5091, and the Wip1/PPM1D inhibitor, GSK2830371, decreased the viability of Ewing sarcoma cells. The combination of ATSP-7041 with P5091, GSK2830371, and chemotherapeutic agents showed synergistic action on the p53 pathway. The effects of the inhibitors, including the specific USP7 Inhibitor XL-188, were rescued by concurrent TP53 knockout, highlighting the essentiality of intact p53 for the observed cytotoxic activities.

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