Docking‐Based Virtual Screening Identifies a Small‐Molecule Inhibitor of the Translesion Synthesis REV7/REV3 Protein–Protein Interaction

REV7 is an adaptor protein that mediates protein–protein interactions (PPIs) in DNA damage response and cell cycle control. REV7 functions as a subunit of the translesion synthesis (TLS) DNA polymerase POLζ, which is involved in the replicative bypass of DNA lesions. REV7 is also a component of the shieldin complex, which mediates the choice of pathway for DNA double‐stranded break (DSB) repair. TLS promotes cancer cell survival after DNA damage and serves as a mechanism through which cancers develop acquired chemoresistance. DSB repair helps cancers mitigate DNA breaks induced by radiation; therefore, inhibition of REV7 PPIs has emerged as a therapeutic strategy. We performed a docking‐based virtual screen to identify compounds predicted to disrupt PPIs between REV7 and the REV7‐binding motifs (RBMs) found in the REV3 subunit of POLζ (TLS) and the SHLD3 subunit of shieldin (DSB repair). Biochemical analysis of a promising hit compound and several analogues demonstrated the ability of this scaffold to disrupt the REV7/RBM _REV3 PPI. Several REV7 inhibitors sensitize human cancer cells to radiation treatment, identifying these compounds as a new class of TLS and DSB‐repair targeted anticancer drugs with potential as adjuvant therapies to improve the efficacy of genotoxic cancer therapies.