Cells in 24-well culture plates were incubated with MEM containing various concentrations of poly(I:C) for 24 hours or the indicated times. For analysis of MMP secretion, culture supernatants were collected and subjected to SDS-polyacrylamide gel electrophoresis on a 10% gel. For analysis of IκB-α phosphorylation and β-actin, cells were lysed in 300 μL solution containing 50 mM Tris-HCl (pH 7.5), 150 mM NaCl, 1 mM EDTA, 5 mM NaF, 1% Nonidet P-40, 0.5% sodium deoxycholate, 0.1% SDS, 1 mM Na3VO4, and 1% protease inhibitor cocktail. The lysates were centrifuged at 15,000g for 10 minutes at 4°C, and the resultant supernatants were subjected to electrophoresis. Separated proteins were transferred to a nitrocellulose membrane, which was then exposed to blocking solution (20 mM Tris-HCl [pH 7.4], 5% dried skim milk, 0.1% Tween 20) before incubation for 16 hours at room temperature with primary antibodies at a 1:1000 dilution in blocking solution. After washing with a solution containing 20 mM Tris-HCl (pH 7.4) and 0.1% Tween 20, the membrane was incubated for 1 hour at room temperature with horseradish peroxidase–conjugated secondary antibodies at a 1:1000 dilution in the same solution, washed again, incubated with ECL reagents for 5 minutes, and then exposed to film.