CBS9106 inhibits TNF-α–induced IκB-α degradation in MM cells. (A) MM.1S cells were treated with vehicle, LMB (10nM), and CBS9106 (50, 200, or 800nM) for 8 hours, followed by vehicle or TNF-α (20 ng/mL) treatment for 25 minutes. The whole-cell lysates were analyzed by immunoblotting. (B) MM.1S cells were treated with vehicle, LMB (10nM), and CBS9106 (200 or 800nM) for 5 hours, followed by vehicle or TNF-α (50 ng/mL) treatment for another 4 hours. The NF-κB activity of the cells was determined by TransAM NF-κB p65 Transcription Factor Assay Kit, according to the manufacturer's instructions. The obtained values (n = 3) are plotted as ratios relative to the corresponding control (vehicle-treated sample). Error bars represent SD.