Autophagy and tumorigenesis.

Autophagy is a catabolic process that captures cellular waste and degrades them in the lysosome. The main functions of autophagy are quality control of cytosolic proteins and organelles, and intracellular recycling of nutrients in order to maintain cellular homeostasis. Autophagy is upregulated in many cancers to promote cell survival, proliferation, and metastasis. Both cell-autonomous autophagy (also known as tumor autophagy) and non-cell-autonomous autophagy (also known as host autophagy) support tumorigenesis through different mechanisms, including inhibition of p53 activation, sustaining redox homeostasis, maintenance of essential amino acids levels in order to support energy production and biosynthesis, and inhibition of antitumor immune responses. Therefore, autophagy may serve as a tumor-specific vulnerability and targeting autophagy could be a novel strategy in cancer treatment.