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Identification of the first small-molecule inhibitor of the REV7 DNA repair protein interaction
Marcelo L Actis1, Nigus D Ambaye1, Benjamin J Evison1
1Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA.
Abstract:
DNA interstrand crosslink (ICL) repair (ICLR) has been implicated in the resistance of cancer cells to ICL-inducing chemotherapeutic agents. Despite the clinical significance of ICL-inducing chemotherapy, few studies have focused on developing small-molecule inhibitors for ICLR. The mammalian DNA polymerase ζ, which comprises the catalytic subunit REV3L and the non-catalytic subunit REV7, is essential for ICLR. To identify small-molecule compounds that are mechanistically capable of inhibiting ICLR by targeting REV7, high-throughput screening and structure-activity relationship (SAR) analysis were performed. Compound 1 was identified as an inhibitor of the interaction of REV7 with the REV7-binding sequence of REV3L. Compound 7 (an optimized analog of compound 1) bound directly to REV7 in nuclear magnetic resonance analyses, and inhibited the reactivation of a reporter plasmid containing an ICL in between the promoter and reporter regions. The normalized clonogenic survival of HeLa cells treated with cisplatin and compound 7 was lower than that for cells treated with cisplatin only. These findings indicate that a small-molecule inhibitor of the REV7/REV3L interaction can chemosensitize cells by inhibiting ICLR.
Insights
Researchers developed a small-molecule inhibitor targeting the REV7/REV3L interaction to block DNA interstrand crosslink repair (ICLR). This approach chemosensitizes cancer cells, potentially enhancing chemotherapy effectiveness.
Area of Science:
- Molecular Biology
- Cancer Research
- Drug Discovery
Background:
- DNA interstrand crosslink repair (ICLR) is crucial for cancer cell resistance to chemotherapy.
- Targeting ICLR with small-molecule inhibitors offers a promising strategy to overcome treatment resistance.
- Mammalian DNA polymerase ζ (REV3L/REV7) is essential for ICLR.
Purpose of the Study:
- To identify small-molecule inhibitors targeting REV7 for blocking ICLR.
- To investigate the potential of REV7/REV3L interaction inhibitors in chemosensitizing cancer cells.
Main Methods:
- High-throughput screening and structure-activity relationship (SAR) analysis to identify inhibitors.
- Nuclear magnetic resonance (NMR) to confirm direct binding of compounds to REV7.
- Reporter plasmid assays to assess ICLR inhibition.
- Clonogenic survival assays in HeLa cells treated with cisplatin and compound 7.
Main Results:
- Compound 1 identified as an inhibitor of REV7/REV3L interaction.
- Compound 7 directly bound to REV7 and inhibited ICLR.
- Compound 7 reduced cancer cell survival when combined with cisplatin, indicating chemosensitization.
Conclusions:
- Small-molecule inhibition of the REV7/REV3L interaction effectively blocks ICLR.
- Targeting REV7 represents a viable strategy to chemosensitize cancer cells to ICL-inducing agents.
- This study provides a foundation for developing novel cancer therapeutics that enhance chemotherapy efficacy.
