Expression, proteolysis and activation of caspases 6 and 7 during rat C6 glioma cell apoptosis.

Activation of cysteinyl aspartate-specific proteases (caspases) may underlie apoptotic cell death in brain. Terminal, executioner caspases 3, 6 and 7 likely contribute to such cell death in a stimulus- and cell type-specific manner. Here we investigate the processing and activation of caspases 3, 6 and 7 in rat C6 glioma cells induced to undergo apoptosis by staurosporine (STS) treatment as a model of apoptosis in glia. Proteolysis and activation of caspases 3 and 7 as determined by immunoblotting and substrate-specific cleavage assay (DEVDase) preceded caspase-6 proteolysis and increased VEIDase activity following STS treatment. Activation of caspase-6 was paralleled by cleavage of the nuclear envelope protein lamin-A. These results highlight temporal differences in the activation of the triad of executioner caspases 3, 6 and 7 during glial cell apoptosis.