Fig. 1.

The dynamic nature of cell death. The specific cell death modality to be initiated is highly dependent on the intensity of the stressor and cellular ATP availability. Under conditions of nutrient deprivation or short-term cellular stress, autophagy is initiated to enhance ATP availability, thereby assisting in the cellular stress response. Prolonged stressors, such as chemotherapy or radiation, activate the apoptotic machinery, which makes use of the ATP provided by the initial autophagic response. Excessively prolonged damage will result in necrosis onset after a rapid decrease in ATP availability