(A, C) HeLa cells were transfected with siRNA targeting IKKα, IKKβ, and IKKγ or control siRNA. Forty-eight hours after the transfection, the cells were further transfected with poly I:C (50 ng/well) for an additional 4 h. (A) The expression of IFN-β mRNA was analyzed by qRT-PCR. Data are presented as the mean ± SD of three independent experiments. *P<0.01. (B, D) Following IKKα RNAi silencing, the cells were transfected with poly I:C (50 ng/well) for 8 h (B) or up to 8 h (C). (B) IFN-β levels were determined by ELISA. All data are shown as the mean of three independent experiments. *P<0.01. (C, D) Protein levels were analyzed by immunoblotting. The results are representative of three independent experiments.