Figure 3. Cytotoxicity caused by GSK3 inhibition is accompanied by down-regulation of NF-κB activity.

NF-κB luciferase reporter assay shows that GSK3 siRNA (A) down-regulates NF-κB activity in U251. (B) Kenpaullone, LiCl and enzastaurin down-regulate NF-κB activity in a dose-dependent manner (24 hours of treatment). (C) NF-κB silencing by siRNA resulted in cytotoxicity of U251. Lower graph shows functional efficiency of NF-κB activity silencing by siRNA in U251 as measured by luciferase reporter assay (NS, non-silencing control siRNA). In all luciferase assays cells were cotransfected with luciferase reporters for NF-κB and b-gal. Luciferase activity levels from NF-κB reporter were divided by those from the b-gal reporter. To control for transfection efficiency and cell viability, a CMV-βgal plasmid was co-transfected. NF-κB and β-galactosidase reporter activities were detected 24 hours after transfection and NF-κB values were normalized compared to β-galactosidase levels. Western Blot shows the efficiency of NF-κB silencing by siRNA.