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. 2011 Jan 17;6(1):e16241. doi: 10.1371/journal.pone.0016241

Figure 3. Bcl-xL mediates TRAIL resistance in the metastatic colon carcinoma cells.

Figure 3

A. Silencing Bcl-xL and survivin expression by siRNAs. SW620 cells were transiently transfected with scramble or gene-specific siRNAs for approximately 20 h and analyzed for Bcl-xL and Survivin mRNA level by RT-PCR. B. Silencing Bcl-xL but not survivin expression significantly increased the tumor cell sensitivity to TRAIL-induced apoptosis. The scramble and gene-specific siRNA-transfected cells were cultured in the absence or presence of TRAIL protein for approximately 24 h and analyzed for apoptosis. ** p<0.01. C. Overexpression of Bcl-xL and Survivin decreased the tumor cell sensitivity to TRAIL-induced apoptosis. SW620 cells were transiently transfected with Vector control (Vector), Bcl-xL-expressing (Bcl-xL) or Survivin-expressing (Survivin) plasmids for approximately 20 h. The cells were then analyzed for Bcl-xL and Survivin mRNA level by RT-PCR (left panel). The cells were also treated with IFN-γ and TNFα for 4 h, followed by incubation with TRAIL protein for approximately 24 h and analysis for apoptosis by PI staining and flow cytometry analysis (right panel). ** p<0.01.