Figure 6

NF-κB inhibition by curcumin does not increase sensitivity to gemcitabine in pancreatic cancer cells. A. Effect of curcumin on basal and TNF-α induced NF-κB activity measured by luciferase reporter assay. PANC-1 and MIA PaCa-2 cells were exposed to curcumin (50 μM, 8 h), TNF-α(30 ng/mL, 4 h), or both after co-transfection with TA-LUC NF-κB reporter and β-gal (internal control) constructs. The normalized values are relative to the untreated control which is represented by dotted line (indicating basal level of NF-κB activity). Each column represents the mean for at least four separate experiments, each with three replicates; error bars = ± SEM. (*) significant: (p < 0.001) when compared to untreated control. (**) significant: (p < 0.0001) when compared to TNF-α treatment. Cur: curcumin, Gem:gemcitabine. B. Growth inhibitory effect of curcumin (2.5–50 μM), gemcitabine (0.05–1.0 μM), and their combination in a 200:1 (curcumin to gemcitabine) ratio was measured by the SRB proliferation assay in MIA PaCa-2 and PANC-1 after 48 h of exposure. Each point represents the mean from three separate experiments, each with six replicates; error bars = ± SEM. Cur: curcumin, Gem: gemcitabine. The results are indicated by relative cell proliferation as a percentage of solvent control. C. Effect of curcumin (50 μM, 8 h), gemcitabine (10 μM, 8 h), and their combination measured by luciferase reporter assay. PANC-1 and MIA PaCa-2 cells were co-transfected with TA-LUC NF-κB reporter construct and β-gal (internal control) and then exposed to curcumin, gemcitabine or both. The normalized values are relative to the untreated control which is represented by dotted line (indicating basal level of NF-κB activity). Each column shows the mean for at least four experiments, each with three replicates; error bars = ± SEM. (*) significant: (p < 0.001) when compared to untreated control. Cur: curcumin, Gem: gemcitabine.