(A) YAC-1 cells were nucleofected with either siGFP control (siGFP) or siUCKL-1. Cell counts were significantly lower at 16, 20, and 24 h after nucleofection of siUCKL-1 compared with siGFP (mean ± SD, n = 5, * P ≤ 0.02, ** P ≤ 0.002, *** P ≤ 0.0002). UCKL-1 down-regulation was confirmed by real-time PCR 24 h after nucleofection. (B) YAC-1 cells nucleofected with siUCKL-1 had more caspase 3/7 activity than siGFP-treated cells (mean ± SD, n = 4, * P ≤ 0.02). Caspase activity was determined by a luminescent assay and UCKL-1 down-regulation confirmed by real-time PCR.