Caspase-3 is not essential for DNA fragmentation in MCF-7 cells during apoptosis induced by the pyrrolo-1,5-benzoxazepine, PBOX-6

Effector caspases-3, -6 and -7 are responsible for producing the morphological features associated with Apoptosis, such as DNA fragmentation. The present study demonstrates that a member of a novel series of pyrrolo-1,5-benzoxazepines, PBOX-6, induces Apoptosis in MCF-7 cells, which lack Caspase-3. Apoptosis was accompanied by DNA fragmentation and the activation of caspase-7, but not caspases-3 and -6. Inhibition of caspase-7 activity reduced the extent of Apoptosis induced, indicating that activation of caspase-7 is involved in the mechanism by which PBOX-6 induces Apoptosis in MCF-7 cells. This study suggests that Caspase-3 is not necessarily essential for DNA fragmentation and the morphological changes associated with Apoptosis.