Fig. 4

Inhibition of PI3K/AKT signaling and increased miR29b levels restore proteasome subunit expression. U266 and RPMI 8226 cells were stimulated with anti-CD28-loaded particles and (A) cultured alone, in the presence of CD28-blocking antibody or the PI3K inhibitor (25 µM LY294002 48 h; 0.5 µM buparlisib 24 h), or (B) cultured alone, transfected with 10 µM miRNA mimic negative control (miR-NC) or miR29b mimic (miR29b). Flow cytometry was used to determine the percentage of cells staining positive for each proteasome subunit. Charts show single values (A) or mean and SD (B) for 7 independent experiments. C Representative flow cytometry plots from untransfected and miR29b-transfected cells showing Zeta, LMP2, LMP7 and LMP10 expression. Histogram overlays show the shift in fluorescence. *P < .05. Wilcoxon signed-rank test