Effect of TLR3 agonist on caspase-3 activation in NB cell lines. (A) Western blot analysis. After treatment with 50 μg/ml poly(I:C) for 24 h, NB cells were harvested and subjected to immunoblot analysis. (B) Quantification of active caspase-3 in NB cells after poly(I:C) treatment. The ratio of active caspase-3 over procaspase-3 level was determined and expressed as mean ± SD from triplicate experiments. **: P < 0.01. *: P < 0.05.