The dual role of autophagy in cancer

Autophagy is a mechanism for the degradation of cytoplasmic material, damaged organelles and aggregate-prone proteins in lysosomes. Recent evidence indicates that autophagy is a tumor suppressor mechanism, which is connected to its role in the clearance of the scaffold protein p62/SQSTM1 and prevention of oxidative stress and genomic instability. However, since autophagy is a survival mechanism, cancer cells can also exploit it to survive nutrient limitation and hypoxia that often occur in solid tumors. Tumor cells can also upregulate autophagy as a response to cancer treatment, and recent studies show that inhibition of autophagy can enhance the killing of tumor cells after treatment. Interestingly, the FK506-binding protein 51 plays a role in the autophagy-linked radiation resistance of malignant melanoma.

► In autophagy, cells can deliver their own cytoplasm to lysosomes for degradation.
► Autophagy delivers nutrients during stresses such as starvation and hypoxia.
► Autophagy prevents tumorigenesis by degrading the scaffold protein p62/SQSTM1.
► Established tumor cells can activate autophagy to survive stress and cancer treatment.
► FKBP51 is upregulated in melanoma and enhances radiation-induced autophagy.