Pretreatment of TrHBMEC with siNQO1 down-regulated TNFα induced E-selectin, VCAM-1, and ICAM-1 proteins. A, TrHBMECs were transfected with siRNAs (either siRNA targeting NQO1 or scrambled siRNA control) for 72 h and then exposed to TNFα (10 ng/ml) for the indicated times. E-selectin, VCAM-1, and ICAM-1 protein levels were examined in TrHBMEC extracts (15 μg) by immunoblot analysis. β-Actin was included as a loading control. The blot is representative of at least three independent experiments. B, semiquantification (as described under Materials and Methods) of relative E-selectin, VCAM-1, and ICAM-1 protein levels after 4 h (peak E-selectin level) or 6 h (peak VCAM-1 and ICAM-1 protein levels) of TNFα induction. n = 3; *, p < 0.05.