Discovery of small molecule inhibitors of human uridine-cytidine kinase 2 by high-throughput screening

• Published in: Bioorganic & medicinal chemistry letters 2019-09, Vol.29 (18), p.2559-2564
• Main Authors: Okesli-Armlovich, Ayse, Gupta, Amita, Jimenez, Marta, Auld, Douglas, Liu, Qi, Bassik, Michael C., Khosla, Chaitan
• Format: Article
• Language: English
• Subjects: De novo pyrimidine synthesis; DHODH inhibitor; Dose-Response Relationship, Drug; Drug Discovery; Enzyme Inhibitors - chemical synthesis; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - pharmacology; GSK983; High-throughput screening; High-Throughput Screening Assays; Humans; Molecular Structure; Pyrimidine processing inhibitors; Pyrimidine salvage; Small Molecule Libraries - chemical synthesis; Small Molecule Libraries - chemistry; Small Molecule Libraries - pharmacology; Structure-Activity Relationship; Uridine; Uridine Kinase - antagonists & inhibitors; Uridine Kinase - metabolism; Uridine-cytidine kinase
• ISSN: 0960-894X; 1464-3405
• DOI: 10.1016/j.bmcl.2019.08.010

[Display omitted] Clinically relevant inhibitors of dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme in mammalian de novo pyrimidine synthesis, have strong antiviral and anticancer activity in vitro. However, they are ineffective in vivo due to efficient uridine salvage by infected or rapidly dividing cells. The pyrimidine salvage enzyme uridine-cytidine kinase 2 (UCK2), a ∼29 kDa protein that forms a tetramer in its active state, is necessary for uridine salvage. Notwithstanding the pharmacological potential of this target, no medicinally tractable inhibitors of the human enzyme have been reported to date. We therefore established and miniaturized an in vitro assay for UCK2 activity and undertook a high-throughput screen against a ∼40,000-compound library to generate drug-like leads. The structures, activities, and modes of inhibition of the most promising hits are described. Notably, our screen yielded non-competitive UCK2 inhibitors which were able to suppress nucleoside salvage in cells both in the presence and absence of DHODH inhibitors.