Effects of NF-κB inhibition combined with anti-MM agents.

(A) MM.1S cells were incubated with or without doxorubicin (doxo; 25 and 50 ng/mL). At 24 hours later, the cells were treated with or without the NF-κB inhibitor SN50 (10 μM) for 18 hours. Cell survival was assayed by MTT. Data shown (mean ± SD) are representative of 3 experiments. The NF-κB inhibitor strongly sensitized MM.1S cells to doxorubicin. (B) SN50 (10 μM) also increased, but to a lesser extent, the anti-MM effect of the proteasome inhibitor PS-341 (5 nM, 18 hours), and dexamethasone (dex; 1 μM, 48 hours).