Silencing effect of predesigned IKKε siRNAs in SK-BR-3 and MCF-7 cells. (a) SK-BR-3 cells were transfected with eight predesigned IKKε siRNAs (siR-1 to siR-8) and negative control siRNA (NC) at a concentration of 50 nM. Cells were harvested 48 hours after the transfection, and the silencing effect at the IKKε mRNA level was determined using real-time RT-PCR. (b) MCF-7 cells were transfected with selected siR-1, siR-8, and NC. The Silencing effect at the IKKε mRNA level was measured using real-time RT-PCR. The silencing effect of IKKε siRNA at the protein level was determined using western blot in (c) SK-BR-3 cells and (d) MCF-7 cells. The effect of IKKε suppression on IKKα, IKKβ and TBK1was examined in (e) SK-BR-3 cells and (f) MCF-7 cells.