title: Pharmacological inhibition of DNA-PK stimulates Cas9-mediated genome editing.
abstract: BACKGROUND
  The ability to modify the genome of any cell at a precise location has drastically improved with the recent discovery and implementation of CRISPR/Cas9 editing technology. However, the capacity to introduce specific directed changes at given loci is hampered by the fact that the major cellular repair pathway that occurs following Cas9-mediated DNA cleavage is the erroneous non-homologous end joining (NHEJ) pathway. Homology-directed recombination (HDR) is far less efficient than NHEJ and makes screening of clones containing directed changes time-consuming and labor-intensive.
  
  
  METHODS
  We investigated the possibility of pharmacologically inhibiting DNA-PKcs, a key player in NHEJ, using small molecule inhibitors (NU7441 and KU-0060648), to ameliorate the rates of HDR repair events. These compounds were tested in a sensitive reporter assay capable of simultaneously informing on NHEJ and HDR, as well as on an endogenous gene targeted by Cas9.
  
  
  RESULTS
  We find that NU7441 and KU-0060648 reduce the frequency of NHEJ while increasing the rate of HDR following Cas9-mediated DNA cleavage.
  
  
  CONCLUSIONS
  Our results identify two small molecules compatible for use with Cas9-editing technology to improve the frequency of HDR.
authors: Department of Biochemistry, McGill University, Montréal, Québec, H3G 1Y6, Canada. francis.robert@mcgill.ca.
authors: Francis
authors: F
authors: Robert
authors: Department of Biochemistry, McGill University, Montréal, Québec, H3G 1Y6, Canada. mathildebarbeau92@gmail.com.
authors: Mathilde
authors: M
authors: Barbeau
authors: Department of Biochemistry, McGill University, Montréal, Québec, H3G 1Y6, Canada. sylvain.ethier@mail.mcgill.ca.
authors: Sylvain
authors: S
authors: Éthier
authors: Department of Biochemistry, McGill University, Montréal, Québec, H3G 1Y6, Canada. josee.dostie@mcgill.ca.
authors: Josée
authors: J
authors: Dostie
authors: Department of Biochemistry, McGill University, Montréal, Québec, H3G 1Y6, Canada. jerry.pelletier@mcgill.ca.|Department of Oncology, McGill University, Montréal, Québec, H3G 1Y6, Canada. jerry.pelletier@mcgill.ca.|The Rosalind and Morris Goodman Cancer Research Center, McGill University, Montréal, Québec, H3G 1Y6, Canada. jerry.pelletier@mcgill.ca.
authors: Jerry
authors: J
authors: Pelletier
mesh_terms: D000818:Animals; D064113:CRISPR-Cas Systems; D002460:Cell Line; D002867:Chromones / Q000494:pharmacology*; D051747:DNA-Activated Protein Kinase / Q000037:antagonists & inhibitors*; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D009025:Morpholines / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D013876:Thiophenes / Q000494:pharmacology*
chemical_list: C576809:2-(4-ethylpiperazin-1-yl)-N-(4-(2-morpholino-4-oxo-4H-chromen-8-yl)dibenzo(b,d)thiophen-1-yl)acetamide; C499693:8-dibenzothiophen-4-yl-2-morpholin-4-yl-chromen-4-one; D002867:Chromones; D009025:Morpholines; D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; D013876:Thiophenes; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human