Caspase-mediated Apoptotic Effects of Ebenus boissieri Barbey Extracts on Human Cervical Cancer Cell Line HeLa

BACKGROUND: Ebenus boissieri Barbey is an Antalya, Turkey-endemic plant belonging to Fabaceae family. The aerial parts and the roots of E. boissieri Barbey were used in this study. OBJECTIVE: In the present study, we have examined the apoptotic effects of hydroalcoholic extracts of E. boissieri Barbey in human cervical cancer cell line HeLa. MATERIALS AND METHODS: To determine the cytotoxic effect, cells were treated with various concentrations of extracts for 24, 48, and 72 h incubation periods. Cytotoxic effects were examined by Cell Titer 96 aqueous nonradioactive cell proliferation assay and the results were corrected by live/dead viability/cytotoxicity assay and trypan blue exclusion assay. Apoptotic effects were studied with multicaspase kit. Tumor necrosis factor-alpha (TNF-α) and interferon gamma (IFN-γ) release were also measured by enzyme-linked immunosorbent assay. RESULTS: According to the results, E. boissieri Barbey extract caused significant increase in caspase levels. Thus, we suggest that the extract induces cells to undergo apoptosis. Especially, there was a sharp induction in caspase-3 activity. Levels of both TNF-α and IFN-γ in extract-treated groups were significantly and dose dependently exalted as compared to their relative controls. CONCLUSION: The effects of the extract on caspase-3, TNF-α, and IFN-γ levels mediate the plausible mechanism of apoptosis induction in HeLa. To the best of our knowledge, this is the first report indicating any pharmacological properties of E. Boissieri on HeLa cells. SUMMARY: HeLa cell viability was reduced in dose-dependent manner for 72 h with an IC50 of approximate 28.03 μg/mL for aerial and 41.02 μg/mL for root. HeLa cells, exposure to the aerial extract led to 1.9, 3.8, 1.2, 2.4, and 3.45 fold induction of all caspases activities (-2, -3, -6, -8, and -9, respectively). Both 30 μg/mL of aerial and 45 μg/mL of root extracts allowed the production of anticancer cytokines (TNFalpha; IFNgamma) in HeLa cell culture supernatants. Abbreviations used: Tumor necrosis factor-alpha (TNF-α); Interferon gamma (IFN-γ); 3-(4, 5 dimethylthiazol-2-yl)-5-(3- carboxymethoxy-phenyl)-2-(4-sulfonyl)-2H-tetrazolium (MTS); Phosphate-Buffered Saline (PBS); Fetal Bovine Serum (FBS); para-Nitroanilin pNA; Enzyme-Linked ImmunoSorbent Assay (ELISA); Sodium Dodesyl sulphate –Polyacrilamide gel electrophoresis (SDS-PAGE); Tris-Buffered Saline (TBS); Hydocloric acid (HCl); Standart Error of Mean (SEM); National Cancer Institute (NCI); half maximal inhibitory concentration (IC(50))