Expression of Apaf-1, procaspase-9, and XIAP in leukemic cell lines.

(A) Western blot analysis of the expression of Apaf-1, procaspase-9, and XIAP protein. Two hundred micrograms of protein was used for Apaf-1 expression. Monoclonal anti–Apaf-1 antibody5 was used at 1:1000 dilution. The ratio K562:CEM:CEM/VLB₁₀₀ for Apaf-1 expression was 1:1:3. 50 μg protein was used for procaspase-9 expression. Monoclonal anti–caspase-9 antibody5 was used at 1:1000 dilution. The ratio K562:CEM:CEM/VLB₁₀₀ for procaspase-9 expression was 2:1:1. 25 μg protein was used for XIAP expression and detected by polyclonal anti-XIAP antibody and was used at 1:1000 dilution. The ratio K562:CEM:CEM/VLB₁₀₀ for XIAP expression was 1:1.2:1. (B) RT-PCR analysis of the expression of procaspase-9 and caspase-9b. (left) DNA size markers (kb); right, 2 caspase-9 isoforms (procaspase-9 1.2 kb; caspase-9b, 0.8 kb).