Related Experiment Video

Updated: Jan 6, 2026

Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1
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Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1

Published on: February 17, 2011

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EXO1 as a therapeutic target for Fanconi Anaemia, ZRSR2 and BRCA1-A complex deficient cancers

Marija Maric1, Sandra Segura-Bayona1, Raviprasad Kuthethur2

  • 1DSB Repair Metabolism Laboratory, The Francis Crick Institute, London, UK.

Nature Communications
|September 26, 2025
PubMed

Insights

Loss of Exonuclease EXO1 is synthetically lethal with DNA damage repair (DDR) gene deficiencies, offering new therapeutic targets for cancers. EXO1 loss creates vulnerabilities exploitable in Fanconi Anemia and ZRSR2-deficient cancers.

Area of Science:

  • Molecular Biology
  • Cancer Genomics
  • DNA Repair

Background:

  • Exonuclease EXO1 is crucial for DNA replication and repair.
  • EXO1 loss is tolerated, suggesting compensatory mechanisms in cancer.
  • Identifying vulnerabilities in DDR-deficient cancers is critical for new therapies.

Purpose of the Study:

  • To identify synthetic lethal interactions with EXO1 loss in cancer.
  • To explore EXO1 as a therapeutic target in DDR-deficient cancers.
  • To elucidate the mechanisms driving synthetic lethality involving EXO1.

Main Methods:

  • CRISPR screening to identify synthetic lethal interactions.
  • Functional assays to assess DNA damage repair and cellular phenotypes.
  • Analysis of replication-coupled repair pathways.

Main Results:

  • EXO1 loss is synthetically lethal with Fanconi Anemia (FA) pathway and BRCA1-A complex genes.
  • ZRSR2 deficiency is synthetically lethal with EXO1 loss, impairing FA pathway activation.
  • FA or ZRSR2 deficiencies depend on EXO1 nuclease activity and are potentiated by PARP inhibitors or radiation.
  • Dysregulated replication-coupled repair, including defective fork reversal, drives synthetic lethality.

Conclusions:

  • EXO1 is a synthetic lethal vulnerability in a wide range of DDR-deficient cancers.
  • Targeting EXO1 offers a promising therapeutic strategy for cancers with unrepaired DNA damage.
  • Understanding EXO1's role in replication-coupled repair is key to developing novel cancer treatments.

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