Catalase-silenced BT-20 KD-CAT cells demonstrate increased caspase activity in the presence of ascorbic acid. BT-20 KD-CAT cells and BT-20 Ctrl cells demonstrated significant differences in caspase activity in the presence of 50 mmol/L and 100 mmol/L ascorbic acid. At lower concentration (10 mmol/L), there were no significant differences (data not shown). The results shown are representative for 3 independent analyses. Values are expressed as mean ± standard deviation and significant differences are shown.