Radiosensitizing effect of polysaccharide in Schisandrae chinensis (Turcz.) Baill. Fruit on ovarian cancer SKOV3 cells

Purpose: To investigate the radiosensitizing effect of polysaccharide from Schisandrae Chinensis fruit (SCFP) on ovarian cancer SKOV3 cell line. Methods: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate SKOV3 cell viability. Caspase-3, caspase-9, Bax, and Bcl-2 levels in SKOV3 cells were assessed by enzyme-linked immunosorbent assay (ELISA). Furthermore, mRNA expression of caspase-3, caspase-9, Bax and Bcl-2 in SKOV3 cells were determined using quantitative real-time polymerase chain reaction (RT-qPCR) assay. Results: β-Irradiation (10 Gy) did not show obvious inhibitory effects on SKOV3 cell proliferation. However, SCFP at a dose of 1.25, 2.5 and 5 mg/mL significantly enhanced the radiosensitivity of SKOV3 cells to β-irradiation (p < 0.01). Furthermore, SCFP at concentrations of 1.25, 2.5 and 5 mg/mL significantly increased the levels of caspase-3, caspase-9 and Bax in SKOV3 cells, but decreased that of Bcl-2 (p < 0.01). In addition, SCFP combined with β-irradiation up-regulated mRNA expression of caspase-3, caspase-9 and Bax (p < 0.01), but down-regulated that of Bcl-2 in SKOV3 cells (p < 0.01). Conclusion: SCFP significantly enhances the sensitivity of nasopharyngeal carcinoma SKOV3 cells to β-irradiation. The possible mechanism of sensitization might be correlated to the induction of mitochondria-mediated apoptosis. This research provides a scientific basis for the development of SCFP for the treatment of ovarian cancer.