A Genome-wide CRISPR Screen Identifies CDC25A as a Determinant of Sensitivity to ATR Inhibitors

Mol Cell. 2016 Apr 21;62(2):307-313. doi: 10.1016/j.molcel.2016.03.006. Epub 2016 Apr 7.


One recurring theme in drug development is to exploit synthetic lethal properties as means to preferentially damage the DNA of cancer cells. We and others have previously developed inhibitors of the ATR kinase, shown to be particularly genotoxic for cells expressing certain oncogenes. In contrast, the mechanisms of resistance to ATR inhibitors remain unexplored. We report here on a genome-wide CRISPR-Cas9 screen that identified CDC25A as a major determinant of sensitivity to ATR inhibition. CDC25A-deficient cells resist high doses of ATR inhibitors, which we show is due to their failure to prematurely enter mitosis in response to the drugs. Forcing mitotic entry with WEE1 inhibitors restores the toxicity of ATR inhibitors in CDC25A-deficient cells. With ATR inhibitors now entering the clinic, our work provides a better understanding of the mechanisms by which these compounds kill cells and reveals genetic interactions that could be used for their rational use.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Ataxia Telangiectasia Mutated Proteins / antagonists & inhibitors
  • Ataxia Telangiectasia Mutated Proteins / genetics
  • Ataxia Telangiectasia Mutated Proteins / metabolism
  • CRISPR-Cas Systems*
  • Cell Cycle Proteins / antagonists & inhibitors
  • Cell Cycle Proteins / metabolism
  • Cell Line
  • Dose-Response Relationship, Drug
  • Drug Resistance, Neoplasm / genetics*
  • Embryonic Stem Cells / drug effects*
  • Embryonic Stem Cells / enzymology
  • Embryonic Stem Cells / pathology
  • Genome-Wide Association Study
  • Humans
  • Mitosis / drug effects
  • Molecular Targeted Therapy
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / metabolism
  • Protein Kinase Inhibitors / pharmacology*
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Protein-Tyrosine Kinases / metabolism
  • RNA Interference
  • Signal Transduction / drug effects
  • Transfection
  • cdc25 Phosphatases / genetics
  • cdc25 Phosphatases / metabolism*


  • Antineoplastic Agents
  • Cell Cycle Proteins
  • Nuclear Proteins
  • Protein Kinase Inhibitors
  • Atr protein, mouse
  • Protein-Tyrosine Kinases
  • Wee1 protein, mouse
  • Ataxia Telangiectasia Mutated Proteins
  • Cdc25a protein, mouse
  • cdc25 Phosphatases