GSK-3α/β-IN-1 is a GSK-3α/β inhibitor with IC50 values of 0.265 μM for GSK-3α and 0.255 μM for GSK-3β. It also inhibits PKA with an IC50 of 0.188 μM. GSK-3α/β-IN-1 effectively reduces cell viability in three glioblastoma (GBM) cell lines (IC50: 3-6 μM over 72 hours) without being toxic to human astrocytes, and it exhibits good metabolic stability. Additionally, it shows potential central nervous system activity in a whole human blood-brain barrier (BBB) GBM model.

GSK-3α:0.265 μM

GSK-3α/β-IN-1 (Compound 1) demonstrates superior kinase selectivity for GSK-3α/β and PKA over other homologous kinases such as CDK2, CDK5, CDK9, ERK1, ERK2, PKBα, PKBβ, PKCα, and PKCγ. It shows strong, dose- and time-dependent inhibition of three glioblastoma (GBM) cell lines—U87-MG, T98G, and U251-MG—at concentrations ranging from 0.3 to 300 μM over 24 to 72 hours. At concentrations of 3.3-6.2 μM for 72 hours, GSK-3α/β-IN-1 significantly reduces G1 phase cell distribution while increasing S phase cell distribution in the same cell lines. When used at 6.2 μM for 72 hours, GSK-3α/β-IN-1 is non-toxic to blood-brain barrier (BBB) cells within a GBM BBB model and maintains BBB integrity. The half-life of GSK-3α/β-IN-1 is over four times longer than that of Verapamil, at 101 minutes, and it has a low intrinsic clearance rate of 5.6 mL/min/mg/protein.