Figure 5

GSK-3 regulates p21 expression, and inhibition of GSK-3 reduces cell viabiliity in bladder carcinoma cell lines. (A) UMUC-3 cells were serum-starved, then treated with GSK-3 inhibitor SB216763 (2.5 μM) over a time course and lysates were immunoblotted for p21 expression. Below, p21 levels normalized to tubulin are shown for UMUC-3 and UMUC-14 cells after treatment for five hours with 2.5 μM SB216763 compared to cells without drug treatment. (B) UMUC-14 cells were transfected with GSK-3α and β expression vectors, and then 48 hours later were serum starved for an additional 24 hours. Cells were subsequently lysed and immunoblotted for GSK-3α and β, p21, β-catenin, and gapdh. (C) An MTS cell viability assay was run on UMUC-3 and UMUC-14 cells treated with SB216763, LY294002, or a combination of the two. UMUC-3 cells were tested by MTS assay after 72 hour drug treatment, and UMUC-14 cells were tested after 48 hour treatment. Asterisks refer to results of Tukey-Kramer post-hoc test comparing cell viabilities at the same concentration of LY294002. *p < .0001; **p < .001.