Figure 4. Effect of p50 siRNA transfection or NF-κB inhibitor on PL-induced cell growth inhibition and expression of Fas and DR4 in NSCLC cells.

(a) Cells were pretreated with NF-κB inhibitor, PAO (0.1 μM) for 1 h and then were treated with PL for 24 h. Cell viability was determined by MTT assay. Data was expressed as the mean ± S.D. of three experiments. *p < 0.05 indicates significantly different from control cells. ^#p < 0.05 indicates significantly different from PL-treated cells. (b) Effect of NF-κB inhibitor (PAO) on the expression of death receptors. Cells were pretreated with PAO (0.1 μM) for 1 h and then were treated with PL for 24 h, and whole cell extracts were analyzed by Western blotting using Fas, DR4 and β-actin (internal control). Each band is representative for three experiments. (c) NSCLC cells were treated with non-targeting control siRNA and p50 siRNA (100 nM) for 24 h, and then were treated with PL (10 μM) for another 24 h. Cell viability was determined by MTT assay. Data was expressed as the mean ± S.D. of three experiments. *p < 0.05 indicates statistically significant differences from control cells. ^#p < 0.05 indicates significantly different from PL treated cells. (d) Effect of p50 knockdown on the expression of death receptors was determined by using Western blotting with antibodies against Fas, DR4 and β-actin (internal control). For the cropped images, samples were run in the same gels under same experimental conditions and processed in parallel. Each band is representative for three experiments. Full-length gels are presented in Supplementary Fig. 6.