Discovery and Structural Optimization of 2-Hydrazinopyrimidin-4-one Analogs Inhibiting Human ADP-Ribosylhydrolase ARH3.
Publisher DOI
PubMed ID
40952342
Abstract
Poly-ADP-ribosylation at sites of DNA damage, catalyzed by PARP enzymes, activates the DNA damage response, chromatin remodeling, and DNA repair. The modification is reversed by two enzymes in humans: PARG, which efficiently hydrolyzes the poly-ADP-ribose chains, and ARH3, which is the key enzyme for removing the last proximal mono-ADP-ribose from serine residues. While inhibitor development has largely focused on PARPs and PARG, no potent and selective inhibitors for ARH3 are currently available. We optimized a FRET-based competition assay for ARH3 and carried out high-throughput screening of small-molecule inhibitors. One hit compound, 1, with a potency of 22 μM was discovered, and through structure-activity relationship studies and synthesis, we improved its potency 10-fold to 2 μM (compound 27, MDOLL-0286). We demonstrate that the compound inhibits ARH3's poly-ADP-ribose hydrolytic activity on cellular substrates. Intriguingly, it does not effectively inhibit the hydrolysis of mono-ADP-ribosylation from natural protein substrates. This is despite the fact that the cocrystal structure of compound 1 bound to ARH3 reveals its overlap with the enzyme's ADP-ribose binding site, agreeing with the competition in the FRET assay. The first experimental ARH3 inhibitor complex provides a valuable starting point for developing more potent chemical probes to study DNA damage response mechanisms in the future.
Date Issued
2025-10-17
Publication Type
Article
Subject(s)
Language(s)
en
Author(s)
Parviainen, Tomi A O | |
Duong, Men Thi Hoai | |
Pääkkönen, Johan | |
Burdova, Kamila | |
Institute of Animal Pathology, Laboratory Cancer Therapy Escape I | |
Lehtiö, Lari | |
Heiskanen, Juha P |
Additional Credits
Institute of Animal Pathology, Laboratory Cancer Therapy Escape I
Journal
ACS Chemical Biology
Publisher
American Chemical Society
ISSN
1554-8937
1554-8929
Access(Rights)
restricted