Analysis of modulators of TRAIL sensitivity after treatment with sFCB. (A) 3.5 × 10⁵ KOB cells/mL were incubated for 24 hours with sFCB. Cells were harvested and Western blot analysis was performed using 30 μg of the cell extract. (B) Activities of NFκB transcription factors. Cells were incubated for 24 hours with or without 2.5 μg/mL of sFCB, nuclear extracts were prepared, and activities of p50 and p65 were evaluated. HeLa cells were used as a positive control and the fold activation was obtained by setting the value for the positive control cells of p50 as 1.0. Values are expressed as mean plus or minus SD.