Evaluation of The Cytotoxicity, Cell Cycle Perturbations and Apoptotic Induction in Human Normal and Cancer Liver Cell Lines Exposed to Potassium Nitrate and Sodium Benzoate

This proposal investigates in vitro cytotoxic and apoptotic effects of two food preservatives commonly consumed in daily meals; potassium nitrate and sodium benzoate. The effect of these two preservatives on cell viability was tested on two different cell lines; normal liver cell line THLE2 and human hepatocellular carcinoma cancer cell line HepG2 using MTT assay. Although the effect was more significantly realized in HepG2 cell line, the viability of both cell lines was decreased by both of the tested compounds. Flow cytometric analysis of the HepG2 treated cells has revealed an increase in G2/M phase cell cycle arrest. Measurement of expression levels of three central genes; p53, bcl-2 and bax that play key roles in cell cycle and apoptosis were carried out in HepG2 using real time-PCR and western blot. In conclusion, both of the tested compounds have decreased the cell line viability and induced both cell cycle arrest and apopototic events indicating their high potential of being cytotoxic and genotoxic materials.