%0 Journal Article
%T Discovery of 3-Amino-1H-pyrazole-Based Kinase Inhibitors to Illuminate the Understudied PCTAIRE Family.
%A Amrhein JA
%A Berger LM
%A Tjaden A
%A Krämer A
%A Elson L
%A Tolvanen T
%A Martinez-Molina D
%A Kaiser A
%A Schubert-Zsilavecz M
%A Müller S
%A Knapp S
%A Hanke T
%J Int J Mol Sci
%V 23
%N 23
%D Nov 2022 27
%M 36499165
%F 6.208
%R 10.3390/ijms232314834
%X The PCTAIRE subfamily belongs to the CDK (cyclin-dependent kinase) family and represents an understudied class of kinases of the dark kinome. They exhibit a highly conserved binding pocket and are activated by cyclin Y binding. CDK16 is targeted to the plasma membrane after binding to N-myristoylated cyclin Y and is highly expressed in post-mitotic tissues, such as the brain and testis. Dysregulation is associated with several diseases, including breast, prostate, and cervical cancer. Here, we used the N-(1H-pyrazol-3-yl)pyrimidin-4-amine moiety from the promiscuous inhibitor 1 to target CDK16, by varying different residues. Further optimization steps led to 43d, which exhibited high cellular potency for CDK16 (EC50 = 33 nM) and the other members of the PCTAIRE and PFTAIRE family with 20-120 nM and 50-180 nM, respectively. A DSF screen against a representative panel of approximately 100 kinases exhibited a selective inhibition over the other kinases. In a viability assessment, 43d decreased the cell count in a dose-dependent manner. A FUCCI cell cycle assay revealed a G2/M phase cell cycle arrest at all tested concentrations for 43d, caused by inhibition of CDK16.