Figure 8

xIAP and cIAP1 confer metastatic human colon carcinoma cells apoptosis resistance. A. IAP protein levels in human colon carcinoma cells. The indicated human colon carcinoma cell lines were analyzed for xIAP and cIAP protein levels by Western blotting analysis. β-actin is used as a normalization control. B. SW620 cells were transiently transfected with scramble siRNA or xIAP- and cIAP1-specific siRNAs, respectively overnight, and analyzed for xIAP and cIAP1 mRNA levels by RT-PCR. C. The transfected cells as shown in A were then treated with FasL (250 ng/ml) for approximately 24 h, stained with Annexin V and PI, and analyzed by flow cytometry. D. Quantification of apoptosis. Percentage of FasL-induced cell death as shown in B is calculated by the formula: % Annexin V⁺ and PI⁺ cells in the presence of FasL- % Annexin V⁺ and PI⁺ cells in the absence of FasL. **p < 0.01.