A resazurin (Alamar Blue) metabolism assay was used to assess cell toxicity during compound treatment [59] . For these experiments, cells were treated with compound or an equivalent concentration of vehicle (DMSO) for 12 h, and the medium was replaced with fresh medium containing resazurin (80% dilution of Tox-8 kit, Sigma-Aldrich, St. Louis, MO). After 1.5 h at 37uC under standard culture conditions, the fluorescence of the resultant product resorufin was measured using the Synergy 4 plate reader. Wells with cells containing no compound (DMSO alone) and wells containing no cells were used as 100% and 0% viability controls. Data were normalized to calculate percentage viability.