Figure 6.

Cartoon illustrating the dark side of apoptosis. Cancer cells with molecular, biochemical, and morphological features of apoptosis are capable of promoting tumor repopulation via different routes, including: (i) secretion of pro-survival factors that is regulated by caspase 3 and involves various signaling pathways, including JNK (c-Jun N-terminal kinase); and (ii) the ability to return from the brink of apoptotic death, resulting in the emergence of progeny with increased numbers of micronuclei and chromosomal abnormalities that can lead to increased aneuploidy, a driving force of aggressive cancer (reviewed in [17]). These various oncogenic functions associated with “dying” (apoptotic) cancer cells include phoenix rising, failed apoptosis, and anastasis. “Treacherous apoptosis” refers to regions within a tumor that are enriched with caspase 3-positive cells (see text for details).