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A small-molecule inhibitor of the BRCA2-RAD51 interaction modulates RAD51 assembly and potentiates DNA damage-induced cell death.

Cell chemical biology (2021-03-05)
Duncan E Scott, Nicola J Francis-Newton, May E Marsh, Anthony G Coyne, Gerhard Fischer, Tommaso Moschetti, Andrew R Bayly, Timothy D Sharpe, Kalina T Haas, Lorraine Barber, Chiara R Valenzano, Rajavel Srinivasan, David J Huggins, Miyoung Lee, Amy Emery, Bryn Hardwick, Matthias Ehebauer, Claudio Dagostin, Alessandro Esposito, Luca Pellegrini, Trevor Perrior, Grahame McKenzie, Tom L Blundell, Marko Hyvönen, John Skidmore, Ashok R Venkitaraman, Chris Abell
ABSTRACT

BRCA2 controls RAD51 recombinase during homologous DNA recombination (HDR) through eight evolutionarily conserved BRC repeats, which individually engage RAD51 via the motif Phe-x-x-Ala. Using structure-guided molecular design, templated on a monomeric thermostable chimera between human RAD51 and archaeal RadA, we identify CAM833, a 529 Da orthosteric inhibitor of RAD51:BRC with a Kd of 366 nM. The quinoline of CAM833 occupies a hotspot, the Phe-binding pocket on RAD51 and the methyl of the substituted α-methylbenzyl group occupies the Ala-binding pocket. In cells, CAM833 diminishes formation of damage-induced RAD51 nuclear foci; inhibits RAD51 molecular clustering, suppressing extended RAD51 filament assembly; potentiates cytotoxicity by ionizing radiation, augmenting 4N cell-cycle arrest and apoptotic cell death and works with poly-ADP ribose polymerase (PARP)1 inhibitors to suppress growth in BRCA2-wildtype cells. Thus, chemical inhibition of the protein-protein interaction between BRCA2 and RAD51 disrupts HDR and potentiates DNA damage-induced cell death, with implications for cancer therapy.

MATERIALS
Product Number
Brand
Product Description

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Glucose Oxidase from Aspergillus niger, Type VII, lyophilized powder, ≥100,000 units/g solid (without added oxygen)
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Anti-phospho-Histone H2A.X (Ser139) Antibody, clone JBW301, clone JBW301, Upstate®, from mouse
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