4.5. Proliferation Assays

Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays (CellTiter 96^® Non-radioactive Cell Proliferation Assay, Promega, Madison, WI, USA). For the experiments, each cell type was seeded into a 96-well plate at a low density, in quintuplicate. Cells were incubated at 37 °C in an atmosphere of 5% CO_2. All samples were processed according to the manufacturer’s instructions. Following the addition of the MTT solution, the cells were incubated for 3.5 h. Absorbance was then recorded at 570 nm using a 96-well plate reader (Envision 2104 multilabel reader, Perkin Elmer, Waltham, MA, USA). Three control wells with medium were used to obtain the blanks of absorbance.