(S)-CR8 is a second generation derivative of (R)-roscovitine and an inhibitor of cyclin-dependent kinase 1 (Cdk1/cyclin B), Cdk2/cyclin A, Cdk2/cyclin E, Cdk5/p25, and Cdk9/cyclin T (IC50s = 0.15, 0.08, 0.06, 0.12, and 0.11 μM, respectively). It also inhibits casein kinase CK1δ/ε (CKδ/ε) and DYRK1A (IC50s = 0.61 and 0.9 μM, respectively). (S)-CR8 reduces cell viability in human neuroblastoma cell lines, including SH-SY5Y, SK-N-AS, SK-N-BE, and IMR32 cells (IC50s = 0.43, 1.46, 0.13, and 0.14 μM, respectively). It also reduces protein levels of the survival factor Mcl-1 in SH-SY5Y cells.
