The cells were transfected with siUNG or siMM at various concentrations for 12 h (A, LNCaP) or 24 h (B, DU145; C, PC3). In combination treatment with H2O2, the cells were transfected with 50 nM siUNG or siMM for 12 h (D, LNCaP) or 24 h (E, DU145; F, PC3) and then exposed to H2O2 for an additional 12 h (D) or 24 h (E and F). In combination treatment with doxorubicin, the cells were transfected with 50 nM siUNG or siMM for 12 h (G, LNCaP) or 24 h (H, DU145; I, PC3) and then exposed to doxorubicin for an additional 12 h (G) or 36 h (H and I). Cells that stained positive for annexin V-FITC (early apoptosis) and positive for FITC and propidium iodide (late apoptosis) were counted. Relative levels of apoptotic indices were expressed as percentage of Silentfect control. (D–I) Filled circles, Silentfect control; filled triangles, siUNG 50 nM; empty circles, siMM 50 nM.