Resazurin-based Assay for Cell Viability

Cell viability after HDAC inhibition was determined by a resazurin-based fluorimetric assay using the CellTiter-Blue^® Cell Viability Assay (Promega, Madison, WI, USA) according to the manufacturer’s instructions. Non-fluorescent resazurin can be reduced to fluorescent resorufin by viable cells, and resorufin fluorescence can be determined (579Ex/584Em) [68 (link)]. Briefly, 100,000 cells were seeded in six-well plates and exposed to TSA or DMSO (control) for 6 h, 24 h, and 48 h. After that, 70 µL of CellTiter-Blue^® was added to 375 µL medium per well and incubated at 37 °C for 1 h. Then, 100 µL was transferred into a 96-well plate and fluorescence was measured by a CytoFluor™ 2350 fluorometer (Millipore, Schwalbach, Germany). Cell viability was calculated relative to the corresponding DMSO controls.