More importantly, when siRNA of UXT, which blocked NF-κB activity, was used in combination with TNF and CHX, we detected drastically morphological changes under light microscopy and ∼50% of cells undergoing apoptosis. Alternatively, we used annexin V and TUNEL methods to quantitatively measure the percentages of cells undergoing apoptosis. Consistently, a considerable increase of apoptotic cells was observed in samples with reduced UXT (Fig. 8, B and C). These indicated that the knockdown of UXT sensitizes 293T cells to apoptosis induced by TNF-α.