Autophagy and Autophagic Cell Death

Macroautophagy or autophagy is a degradative pathway terminating in the lysosomal compartment after the formation of a cytoplasmic vacuole that engulfs macromolecules and organelles. During the last decade, progress made in our understanding of the molecular controls of autophagy has uncovered the importance of tumor suppressor molecules in the stimulation of autophagy. Downexpression of autophagy is an early event during tumorigenesis. However, the relation between autophagy and tumor progression seems to be more complex because cancer cells are able to trigger autophagy in response to various situations including changes in their extracellular environment and cancer treatments. The role of autophagy in cancer cells balances between two apparently opposite outcomes. Autophagy as a stress response mechanism can protect cancer cells from various insults. But autophagy can eliminate cancer cells by triggering autophagic cell death. These two aspects of autophagy will be discussed in this review.