Fig. 1. Resistance to CD95-induced apoptosis correlates with expression of FAP-1. (A) Relative sensitivity to CD95-mediated cell death in two pancreatic carcinoma cell lines. Cells were treated for 24 hours with various concentrations of the agonistic anti-CD95 antibody CH11 prior to measurement of DNA fragmentation using the JAM assay. Data are expressed as % viability, with untreated control cells set arbitrarily to 100, and values are means of six determinations. Standard deviations were below 10%. (B) RT-PCR analysis of FAP-1, c-FLIP and GAPDH mRNAs in Panc89 and Capan-1 cells. The inclusion of samples in which reverse transcriptase (RT) had been omitted (-) served to rule out false positive results by contaminating genomic sequences. Jurkat cells were used as a negative control for FAP-1 and c-FLIP. The parallel amplification of a GAPDH-specific sequence served to validate integrity of the input RNA. (C) Immunoblot analysis of FAP-1 in Panc89 and Capan-1 cells. Full-length FAP-1 from Panc89 cells migrates as a band of approximately 250 kDa. Specificity of the anti-FAP-1 antibody was confirmed by competition (Comp) with the respective blocking peptide.