Caspase 3 Activity Assay

Caspase activities were measured with a caspase activity kit according to the manufacturer’s instructions (BioVision, Mountain View, CA, USA). Briefly, after different treatments, cells were washed with cold PBS, resuspended in lysis buffer, and left on ice for 15 min. The lysate was centrifuged at 16,000 g at 4 °C for 15 min. Activity of caspase 3 was measured with the use of the substrate peptide Ac-DEVDp-nitroanilide. We qualified the release of p-nitroanilide by determining the absorbance with a spectrophotometric plate reader at 405 nm. The fold increase in activity was calculated as the ratio between values obtained from treated samples versus those obtained from untreated controls.