MTS assay

The effect on cellular proliferation was evaluated using Cell Titer96^® Aqueous One Solution Cell Proliferation Assay Kit (Promega, USA). This kit contains an MTS reagent, which was composed of [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] and phenazinemethosulfate (PMS). 2 × 10³ cells were plated into each well of 96-well plates and incubated in regular culture medium for 6 h. Then, cells were treated with indicated doses of the agents for 48 h. 20 μL MTS reagents were added into each well and incubated at 37 °C for 2 h. The absorbance was measured at 490 nm. Experiments were performed in triplicate.