Western blot analysis was performed using antibodies specific for NF-κB p50 and p65, MT1-MMP, and CD44. Media and cytoplasmic and nuclear fractions were subjected to SDS gel electrophoresis under reducing conditions using 4% to 15% gradient gels (Bio-Rad). The proteins were transferred to nitrocellulose membranes and incubated with anti-NF-κB p50 (1:1000 dilution; Santa Cruz Biotechnologies, Inc., Santa Cruz, CA), anti-NF-κB p65 (1:1000; Santa Cruz Biotechnologies, Inc.), anti-active MT1-MMP (RP3MMP14, 1:5000 dilution; Triple Point Biologics, Inc., Forest Grove, OR), anti-pro form MT1-MMP (RP4MMP14, 1:5000, Triple Point Biologics, Inc.), or anti-CD44 antibody (BU52, 1:1000 dilution; Ancell, Bayport, MN) for 16 hours at 4°C. The membranes were rinsed, incubated with a goat anti-mouse-horseradish peroxidase (HRP) conjugate (1:3000 dilution; Bio-Rad), and visualized on x-ray film using enhanced chemiluminescence according to the manufacturer’s instructions (GE Healthcare, Arlington Heights, IL).