Multiskan 1500 microplate reader

The activity of DNMT was determined by EpiQuik DNMT Activity/Inhibition Assay Ultra Kit (Colorimetric) (Epigentec Group Inc., Farmingdale, NY, USA) in ovarian cancer cells treated with ginsenoside Rg3 (0, 50, 100 and 200 µg/ml) or 50 µg/ml 5-aza-dc (as a negative control). The samples were first co-incubated with cytimidine substrate and then with 5′-methyl-cytimidine antibody. The activity of HDAC was determined using Epigenase HDAC Activity/Inhibition Direct Assay Kit (Colorimetric) (Epigentec Group Inc.) in ovarian cancer cells treated with ginsenoside Rg3 (0, 50, 100 and 200 µg/ml) or 500 ng/ml HDAC inhibitor trichostatin A (TSA) (Selleck Chemicals, Houston, TX, USA) (as a negative control). The samples were co-incubated with acetylated substrate and then with photographic developer. The OD values at 450 nm were measured using a MultiSkan 1500 microplate reader (Thermo Fisher Scientific, Inc.).

A Cell Counting Kit-8 (CCK-8; Beyotime Institute of Biotechnology, Haimen, China) assay was carried out to determine cell viabilities. Briefly, cells (5×10³/well) treated with different concentrations of cisplatin and ginsenoside Rg3 were inoculated in 96-well plates. After having been incubated for 12, 24 and 48 h, the cells were stained with 20 µl staining reagent for 1 h. The optical density (OD) values at 450 nm were read using a MultiSkan 1500 microplate reader (Thermo Fisher Scientific, Inc., Waltham, MA, USA).