Biologic and molecular consequences of silencing TAK1 expression in lymphoma. (A) A representative experiment of TAK1 gene silencing with the use of 3 different siRNAs in lymphoma cell lines. TAK1 protein levels were determined by Western blot after 48 hours of transfection. Similar results were obtained in 2 additional independent experiments. (B) TAK-1 gene silencing decreased the phosphorylation of p38 and IκBα without affecting ERK phosphorylation. Results are shown after 48 hours of transfection. (C) TAK1 gene silencing resulted in induction of apoptosis in lymphoma cell lines, as determined by the annexin V/propidium iodide staining method and FACS analysis. This is a representative experiment performed after 48 hours of transfection with TAK1 siRNA or control siRNA. (D) Summary results of TAK1 siRNA–induced cell death. Each value is the mean of 3 independent experiments performed in triplicate (± SEM). **P < .005. Open bars indicate RPMI; gray bars, control siRNA; and black bars, TAK1 siRNA3.