CA3 and central nervous system cancer: The presence of cyt c in the cytosol and activation of caspase 3 was determined by Western blot in C6 glioma cells exposed to Cas III-ia (Figure 4D); significant release of cyt c into the cytosol was found at 10, 15 and 20 μg/ml of Cas III-ia when compared with controls and significant activation of caspase 3 at all doses of Cas III-ia.