NF-κB mediates TWIST1- induced IL8 promoter activation. (A) IL8 promoter-driven relative luciferase activities of SKBR3 (left) and MCF7 (right) cells 24 h after transfection with TWIST1 (Tw) and/or IκBSR. (B) Relative luciferase activities of BT549 cells 24 h post-transfection with the IL8 WT promoter with or without IκBSR, or ΔκB IL8 mutant promoter alone. (C) Relative luciferase activities of SKBR3 (left) and MCF7 (right) cells transfected with ΔκB or WT IL8 promoter in the presence or absence of TWIST1 and/or TNF stimulation (40 ng/ml). Data are from single representative experiments. Mean ± SD, n = 3, ** P ≤ 0.01.