RESUMO
BACKGROUND: Exopolysaccharide, a carbohydrate polymer, is known to possess several biological activities. This approach was designed to clarify the cytotoxic mechanism of Bacillus sonorensis exopolysaccharide (EPS-1) on Huh7, HepG2 and BNL cells besides exploring its influence on the expression of the tumor suppressor protein p53. p53 is the biomarker of the prognosis and occurrence of severe stages of the tumor and activation of both cell-cycle arrest and apoptosis in cancer cells which are the most targeted cellular processes for the therapy of tumor patients. METHODS: The cytotoxic impact of EPS-1 was quantified via neutral red uptake assay and the results were confirmed by a morphology study. The expression level of p53 was analyzed using quantitative real-time PCR. RESULTS: The outcomes of the present study explicated that EPS-1 with IC 50 = 164 and 398 µg ml -1 exhibited an inhibitory influence on Huh7 and HepG2 cells growth after 48 h incubation time respectively. EPS-1 showed no influence on normal BNL cells. Furthermore, the molecular genetic analysis revealed that EPS-1 provoked significant upregulation in the expression level of the p53 gene in the treated Huh7 cell line more than that in HepG2, whereas no significant gene expression was noticed in BNL cells ( P = 0.006, 0.65 and 0.83), respectively. CONCLUSION: The antitumor activity displayed by this compound may be of interest for further studies of its structure-activity relationship. Before application in phase 1 of the clinical study, in-vivo studies would be needed to confirm the results obtained in the hope of finding more active and selective anticancer agents for drug development in the future.