NF-κB inhibitor parthenolide has little effect on 2ME2 or Doc cell death in DU145 and PC3 cells. Trypan blue exclusion assay showing that 72 h treatment with parthenolide (P; 10-20 μM) does not significantly increase 2ME2 (M; 5 μM) or Doc (D; 1 nM) cell death (% dead cells), with the exception of M vs. MP and P vs. DP in DU145 (*, P < 0.02) and M vs. MP and D vs. DP in PC3 cells (*, P < 0.01). Cell death in control treated cells is < 5%. n = 4-5, three independent experiments. Western blot analysis at 24 h shows that P inhibits P-IκBα/IκBα in DU145 and PC3 cells. Coomassie blue stain of total protein is loading control.