FIGURE 3.
Long term treatment of DU145 cells with cell-permeable p27Kip1 peptide induces apoptosis. A, DU145 cells were treated with 20 μm FITC-labeled cell-permeable Arg8, R8-T198wt, or R8-T198mu peptide or not treated with any peptide (None). After incubation for 72 h, cells were stained with propidium iodide. Analyses were performed using a flow cytometer. B, expression levels of endogenous caspase-3, poly(ADP-ribose) polymerase, and β-actin proteins in cells treated as in A were confirmed by immunoblotting. C, HEK293T cells were cultured in serum-free medium for 24 h. Cells were then transfected with empty pc5FLAG alone (−) or pc5FLAG encoding Pim-1 (+). After transfection for 4 h, medium was replaced with serum-free medium containing none (None) or 40 μm FITC-labeled Arg8, R8-T198wt, or R8-T198mu peptide and incubated for an additional 24 h. Then, cell lysates were electrophoresed and immunoblotted with the indicated antibodies.