Effect of dexamethasone on binding activity of transcription factors nuclear factor-kappaB and activator protein-1 in SW982 human synovial sarcoma cells.

Previously, we showed that dexamethasone (DEX) inhibited the expression of inflammatory cytokines, matrix metalloproteinase-1, and cyclooxygenase-2 messenger ribonucleic acid in SW982 cells. In this study, the effect of DEX on the transcription factors nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) was examined in SW982 cells by electrophoretic mobility shift assay (EMSA). Both NF-kappaB and AP-1 deoxyribonucleic acid binding activities were detectable in SW982 cells by EMSA, and they were induced by interleukin-1beta treatment. DEX inhibited NF-kappaB binding activity at 10 microM as well as at 100 microM, although the inhibition was only partial. However, DEX had little effect on AP-1 activity. These results suggest that DEX reduces the expression of inflammatory cytokines and other proteins in SW982 cells by inhibiting NF-kappaB.