Figure 1.
(A) PS-341 inhibits the activation of NF-κB in TNFα-treated HUVE cells. Different concentrations of PS-341 were added to HUVE cells (lanes 3–6) 1 hr before treating with TNFα (1,000 units/ml; 10 ng/ml) for 30 min. In lanes 1 and 2, the cells were pretreated with the inhibitor diluent DMSO. TNFα was added to the cells in lanes 2–6. Electrophoretic mobility shift assay was performed as described in Materials and Methods. NS is a nonspecific DNA-binding complex. (B) PS-341 inhibits the degradation of IκBα in TNFα-treated HUVE cells. HUVE cells were pretreated with PS-341 (5 μM) for 1 hr before the addition of TNFα (1,000 units/ml; 10 ng/ml) for different periods of time. IκBα protein levels were measured by Western analysis as described in Materials and Methods. ∗, phosphorylated IκBα.