Determination of cFLIP and procaspase-8 levels in untreated myeloma cells.

Untreated myeloma cells were lysed in whole cell lysate buffer and 80 μg protein separated on a 12% SDS-PAGE gel. Procaspase-8 was detected as described above. Membranes were then stripped and reprobed with the cFLIP monoclonal antibody G-11 (Santa Cruz). Tubulin detection was used to confirm equal protein loading. The procaspase-8/cFLIP ratios were calculated for each cell line densitometrically and do not correlate with the amount of TRAIL-induced apoptosis (r = 0.7,p = 0.19, Spearman rank correlation).