Discovery of Potent and Selective MTH1 Inhibitors for Oncology: Enabling Rapid Target (In)Validation.
Farand, J., Kropf, J.E., Blomgren, P., Xu, J., Schmitt, A.C., Newby, Z.E., Wang, T., Murakami, E., Barauskas, O., Sudhamsu, J., Feng, J.Y., Niedziela-Majka, A., Schultz, B.E., Schwartz, K., Viatchenko-Karpinski, S., Kornyeyev, D., Kashishian, A., Fan, P., Chen, X., Lansdon, E.B., Ports, M.O., Currie, K.S., Watkins, W.J., Notte, G.T.(2020) ACS Med Chem Lett 11: 358-364
- PubMed: 32184970 
- DOI: https://doi.org/10.1021/acsmedchemlett.9b00420
- Primary Citation of Related Structures:  
6US2, 6US3, 6US4 - PubMed Abstract: 
We describe the discovery of three structurally differentiated potent and selective MTH1 inhibitors and their subsequent use to investigate MTH1 as an oncology target, culminating in target (in)validation. Tetrahydronaphthyridine 5 was rapidly identified as a highly potent MTH1 inhibitor (IC 50 = 0.043 nM). Cocrystallization of 5 with MTH1 revealed the ligand in a Φ- cis - N -(pyridin-2-yl)acetamide conformation enabling a key intramolecular hydrogen bond and polar interactions with residues Gly34 and Asp120. Modification of literature compound TH287 with O - and N -linked aryl and alkyl aryl substituents led to the discovery of potent pyrimidine-2,4,6-triamine 25 (IC 50 = 0.49 nM). Triazolopyridine 32 emerged as a highly selective lead compound with a suitable in vitro profile and desirable pharmacokinetic properties in rat. Elucidation of the DNA damage response, cell viability, and intracellular concentrations of oxo-NTPs (oxidized nucleoside triphosphates) as a function of MTH1 knockdown and/or small molecule inhibition was studied. Based on our findings, we were unable to provide evidence to further pursue MTH1 as an oncology target.
Organizational Affiliation: 
Gilead Sciences, Inc. 333 Lakeside Drive, Foster City, California 94404, United States.