CR8, (R)-Isomer is a cell-permeable (R)-DRF053 (sc-221408) analog that acts as an ATP-binding pocket-targeting CDK/CK1 dual-specific inhibitor (IC50 = 0.09, 0.072, 0.041, 0.11, 1.10, 0.18, and 0.40 μM against CDK1/B (cyclin dependent kinase 1/B), CDK2/A (cyclin dependent kinase 2/A), CDK2/E (cyclin dependent kinase 2/E), CDK5/p25 (cyclin dependent kinase 5/p25), CDK7/H (cyclin dependent kinase 7/H), CDK9/T (cyclin dependent kinase 9/T), and CK1δ/ε, respectively). (R)-CR8 inhibits CDK/CK1 more effectively than (R)-Roscovitine, while maintaining similar selectivity profile over other types of kinases (IC50 = 3.6, 3.6, and 12.0 μM against Dyrk1A, Erk2, and GSK-3α/&beta (glycogen synthase kinase-3α/β), respectively). Both (R)-CR8 and (S)-enantiomers are much more effective than (R)-Roscovitine in apoptosis induction in cell cultures.
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