Figure 1: Diagram of the autophagy process. Under cellular stress, class III PI3K/Beclin-1 complex initiates vesicle nucleation and autophagosome formation. An autophagosome with cytoplasmic constituents fuses its membrane with a lysosome to form an autophagolysosome. Inside the autophagolysosome, cytoplasmic materials get degraded by lysosomal hydrolases, serving as a source of energy and allowing cancer cell survival during periods of hypoxia and nutrient deprivation, especially in the setting of therapeutic insult, such as radiation.