XIAP is implicated in the BBR-induced apoptosis in ALL cells. (A–B) Relative expression at the mRNA and protein levels of XIAP in ALL cells, KOPN-8, EU-4, NALM-6, EU-6, and SEM. H9 human lymphoma cells served as a control. EU-4 and EU-6 cells were treated by BBR at the indicated concentrations for 24 h. (C–D) Expression of XIAP mRNA in EU-4 and EU-6 cells. (E–F) Representative western blot analysis showing the effect of BBR on the expression of XIAP in EU-4 and EU-6 cells. (G–H) EU-4 and EU-6 cells were transfected with vector containing XIAP, or negative vector, and subsequently treated with 50 μM BBR for 24 h. Cell apoptosis was measured by TUNEL assay. The numbers above the western blots band are the quantification of the gray value normalized to control group. Results are expressed as mean ± SD. *p<0.05, **p<0.01, ***p<0.001, compared to the control or indicated group.