Modes of Cell Death Apoptosis, Autophagy and Necrosis

8 Modes of Cell Death Apoptosis, Autophagy and Necrosis 

Epithelial cells of the GI tract are exposed to various agents (as indicated in previous sections) and conditions that activate stress-response pathways. This results in either cell survival or cell death. Those cells with inadequate cellular defenses may die by one of three major cell death mechanisms, apoptosis, autophagy or necrosis, depending upon the particular stress conditions. 

Although autophagy is biochemically and morphologically distinct from apoptosis, there is significant cross-talk between these signalling pathways. 

We have recently shown, in Seg-1 cells derived from a patient with esophageal adenocarcinoma, that bile acids and low pH induce the dramatic formation of autophagic vacuoles (unpublished data). We also showed that persistent treatment of Het-IA cells (derived from normal human esophageal squamous epithelium) with a bile-acid cocktail and low pH resulted in the development of mutated clones that contain a partly duplicated chromosome 16 (unpublished data from a CGH microarray). In addition to other protective genes, this chromosome 16 duplication resulted in the duplication of the major ATPase necessary for the acidification of vesicles associated with the autophagic process. 

Bernstein and H. Bernstein, Apoptosis overview emphasizing the role of oxidative stress, DNA damage and signal-transduction pathways, Leuk. Lymphoma, 1995, 19(1-2), 43. 

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