Figure 4

GSK-3 inhibition increases MM cell sensitivity to bortezomib-induced apoptosis. (A) Histograms summarizing the data on the percentage of apoptotic MM cells, evaluated by annexin V staining and FACS analysis, left untreated (white bars) treated with the GSK-3 inhibitor SB415286 (4 μM) (black bars), bortezomib (BZ) 5 nM (black and white dashed bars) or both (black, white-dotted bars). Top graphs: U-266 cells, bottom: RPMI-8226 cells. Data represent mean ± SEM, n = 3. * indicates p < 0.05 by one-way ANOVA test. (B) Representative WB analysis of nuclear (n) and cytosolic (c) proteins from U-266 cells untreated, treated with 4 μM SB415286, with 5 nM BZ or both, showing the levels of PARP and cleaved PARP, Ser 473-phosphorylated AKT, AKT and MCL-1. Nucleophosmin and GAPDH were used as nuclear and cytosolic loading controls, respectively.