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. 2011 Mar 31;6(3):e18330. doi: 10.1371/journal.pone.0018330

Figure 6. XIAP knockdown sensitizes cells to TRAIL-induced cell death despite Bid inhibition.

Figure 6

A, KMCH cells were incubated for 24 hours in medium or cyclopamine (5 µM) followed by treatment with either vehicle (DMSO, final concentration 0.1% v/v) or the Bid inhibitor, BI-6C9 (10 µM) for 1 hour. Cells were subsequently treated with Fas agonistic antibody CH-11 (100 µg/mL) for an additional 5 hours (where appropriate, BI-6C9 remained in the medium during CH-11 treatment). Cells with apoptotic nuclear morphology were quantified as referenced in the Materials and Methods. Mean +/− SEM; ***p<0.001; n.s. indicates p>0.10 by ANOVA with Bonferroni correction. B, KMCH cells were incubated overnight with or without cyclopamine followed by BI-6C9 as in panel A, except that apoptosis was induced by TRAIL (5 ng/mL) for 5 hours (where appropriate, BI-6C9 remained in the medium during TRAIL treatment) and apoptotic nuclear morphology was quantified. Mean +/− SEM; ***p<0.001; n.s. indicates p>0.10 by ANOVA with Bonferroni correction. C, KMCH cells transiently transfected with XIAP siRNA or scrambled siRNA (48 hours) were pretreated with BI-6C9 (10 µM) or DMSO vehicle (final concentration 0.1% v/v) for 1 hour. Next, the cells were treated with TRAIL (5 ng/mL) for 5 hours (where appropriate, BI6C9 remained in the medium during TRAIL treatment). Cells with apoptotic nuclear morphology were quantified. Mean ± SEM, *p<0.05; n.s. indicates p>0.10 by ANOVA with Bonferroni correction.