Identification and evaluation of small-molecule inhibitors against the dNTPase SAMHD1 via a comprehensive screening funnel.

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Zhang SM, Paulin CBJ, Shu H, Yagüe-Capilla M, Michel M, Marttila P, Ortis F, Bwanika HC, Dirks C, Venkatram RP, Wiita E, Jemth A, Almlöf I, Loseva O, Hormann FM, Koolmeister T, Linde E, Lee S, Llona-Minguez S, Haraldsson M, Axelsson H, Strömberg K, Homan EJ, Scobie M, Lundbäck T, Helleday T, Rudd SG

iScience 27 (2) 108907 [2024-02-16; online 2024-01-13]

SAMHD1 is a dNTP triphosphohydrolase governing nucleotide pool homeostasis and can detoxify chemotherapy metabolites controlling their clinical responses. To understand SAMHD1 biology and investigate the potential of targeting SAMHD1 as neoadjuvant to current chemotherapies, we set out to discover selective small-molecule inhibitors. Here, we report a discovery pipeline encompassing a biochemical screening campaign and a set of complementary biochemical, biophysical, and cell-based readouts for rigorous characterization of the screen output. The identified small molecules, TH6342 and analogs, accompanied by inactive control TH7126, demonstrated specific, low μM potency against both physiological and oncology-drug-derived substrates. By coupling kinetic studies with thermal shift assays, we reveal the inhibitory mechanism of TH6342 and analogs, which engage pre-tetrameric SAMHD1 and deter oligomerization and allosteric activation without occupying nucleotide-binding pockets. Altogether, our study diversifies inhibitory modes against SAMHD1, and the discovery pipeline reported herein represents a thorough framework for future SAMHD1 inhibitor development.

Chemical Biology Consortium Sweden (CBCS) [Collaborative]

PubMed 38318365

DOI 10.1016/j.isci.2024.108907

Crossref 10.1016/j.isci.2024.108907

pmc: PMC10839966
pii: S2589-0042(24)00128-7