Figure 6

NBD peptide inhibits NF-κB transcriptional activity and increases the antiproliferative effect of TMZ in M10 cells. (A) Melanoma cells were transiently co-transfected with the NF-κB-Luc and pRL-null vectors and treated with NBD peptide, TMZ and BG as described under “Methods”. Luciferase assays were performed after 72 of drug exposure. Data are expressed in terms of fold changes (i.e. the ratio between firefly luciferase activity/μg protein detected in cells exposed to NBD+BG, or TMZ+BG or NBD+TMZ+BG and that detected in cells treated with BG alone). Values represent the mean of six independent experiments performed with duplicate samples. Bars, SEM. Statistical analysis was performed on firefly luciferase activity/μg protein values according to paired Student’s t test. p values were as follows: **p<0.01, NBD+BG versus BG; ^#p<0.05, TMZ+BG versus BG; ^§p<0.05 TMZ+BG versus NBD+TMZ+BG; ^^p<0.01, NBD+TMZ+BG versus NBD+BG. The differences between firefly luciferase activity/μg protein of cells treated with NBD+TMZ+BG and that of cells exposed to BG alone was not statistically significant. (B) M10 cells were treated with NBD peptide, TMZ and BG as described under “Methods” and assayed for proliferation by the MTT assay. Percentage of growth of TMZ+BG-treated cells was determined with respect to BG-treated cells (CTRL-1), and that of NBD+TMZ+BG-treated cells with respect to either BG-treated cells (CTRL-1) or NBD+BG-treated cells (CTRL-2). Values represent the mean of four independent experiments. Bars, SEM. **p<0.01, and *p<0.05, according to Student’s t test analysis, comparing TMZ IC₅₀ values of NBD+TMZ+BG-treated cells with those of TMZ+BG-treated cells.