Apoptosis-inducing effect of the DR5 monoclonal antibody, D-6, alone or in combination with cisplatin, on A2780 ovarian cancer cells.

Death receptor 5 (DR5) antibody (D-6) is a monoclonal antibody directed against DR5. The aim of this study was to explore the apoptosis-inducing effects of DR5 (D-6), alone or in combination with cisplatin, on A2780 ovarian cancer cells. The cells were treated with various concentrations of cisplatin and/or DR5 (D-6), or a combination of both. For the control group, the cells were treated only with culture medium. Twenty-four hours after the culture, the morphological changes of each group were observed under an inverted microscope. The cell growth inhibition rates were also analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide (MTT) assays, and the apoptosis was analyzed by flow cytometry. Western blotting analysis was used to detect the intracellular reaction. Our results showed that DR5 monoclonal antibody (D-6) was able to induce the apoptosis and increase the cell growth inhibition rates of ovarian cancer cells in a dose-dependent manner, and the effect was enhanced by cisplatin. There were significant morphological changes, a higher cell growth inhibition rate and apoptosis rate and lesser expression of caspase-3, 8, 9 precursors in the cells treated with both cisplatin and DR5 (D-6). The combination treatment of the DR5 monoclonal antibody (D-6) with cisplatin may be a promising treatment for ovarian cancer.