Ionizing radiation but not anticancer drugs causes cell cycle arrest and failure to activate the mitochondrial death pathway in MCF-7 breast carcinoma cells

There is considerable evidence that ionizing radiation (IR) and chemotherapeutic drugs mediate apoptosis through the intrinsic death pathway via the release of mitochondrial cytochrome c and activation of caspases -9 and -3. Here we show that MCF-7 cells that lack caspase-3 undergo a caspase-dependent apoptotic cell death in the absence of DNA fragmentation and α-fodrin cleavage following treatment with etoposide or doxorubicin, but not after...