Food Additive Sodium Benzoate (NaB) Activates NFκB and Induces Apoptosis in HCT116 Cells

NaB, the metabolite of cinnamon and sodium salt of benzoic acid is a commonly used food and beverage preservative. Various studies have investigated NaB for its effects on different cellular models. However, the effects of NaB on cancer cell viability signaling is substantially unknown. In this study, the effects of NaB on viability parameters and NF kappa B, one of the most important regulators in apoptosis, were examined in HCT116 colon cancer cells. Cell culture, light microscopy, spectrophotometry, flow cytometry, and western blot were used as methods to determine cell viability, caspase-3 activity, NF kappa B, Bcl-xl, Bim, and PARP proteins, respectively. NaB (6.25 mM-50 mM) treatment inhibited cell viability by inducing apoptosis, which was evident with increased Annexin V-PE staining and caspase-3 activity. NF kappa B activation accompanied the induction of apoptosis in NaB treated cells. Inhibition of NF kappa B with BAY 11-7082 did not show a pronounced effect on cell viability but induced a more apoptotic profile, which was confirmed by increased PARP fragmentation and caspase-3 activity. This effect was mostly evident at 50 mM concentration of NaB. Bcl-xl levels were not affected by NaB or BAY 11-7082/NaB treatment; whereas, total Bim increased with NaB treatment. Inhibition of NF kappa B activity further increased Bim levels. Overall, these results suggest that NaB induces apoptosis and activates NF kappa B in HCT116 colon cancer cells. Activation of NF kappa B emerges as target in an attempt to protect cells against apoptosis.