NF-κB inhibitors induce apoptosis in Tax transgenic tumor cells. Fresh tumor and spleen cell suspensions from nontransgenic and Tax transgenic mice were incubated in the presence or absence of 10 mM sodium salicylate or PS-341 for 20 hours prior to treatment with 30 Gy (3000 rads) irradiation. Five hours after irradiation, 105 cells were stained with fluorescein isothiocyanate–conjugated annexin V (FL1) to evaluate cells in early apoptosis. Total numbers of dead cells were measured by propidium iodide staining (FL-2). Apoptotic cells are indicated by annexin V–positive population, and the percentage apoptotic cells is shown. Error bars represent SEM between 5 mice in 1 representative experiment of 3 experiments consisting of 5 nontransgenic and 5 transgenic mice each. The statistical significance of the inhibition was evaluated by a paired t test: P ≤ .01 for untreated compared to sodium salicylate treatments and P ≤ .03 for untreated compared to PS-341 treatments.
