Cellular and metabolic functions for autophagy in cancer cells

• Autophagy sustains metabolic pathways required for aggressive tumor growth.
• The unfolded protein response induces cytoprotective autophagy in stressed tumors.
• Autophagy facilitates anoikis resistance and tumor cell invasion.
• Selective autophagy cargo receptors control multiple pro-tumor signaling pathways.

Autophagy is a lysosomal degradation pathway that acts as a dynamic regulator of tumorigenesis. Specifically, autophagy has been shown to impede early cancer development while facilitating advanced tumor progression. Recent studies have uncovered several tumor-promoting functions for autophagy; these include the maintenance of multiple metabolic pathways critical for aggressive tumor growth and the promotion of tumor cell survival downstream of the unfolded protein response. Furthermore, autophagy supports anoikis resistance and cancer cell invasion. At the same time, because autophagy cargo receptors, which are essential for selective autophagy, lie upstream of diverse cancer-promoting signaling pathways, they may profoundly influence how alterations in autophagy affect tumor development. This review focuses on how these tumor cell autonomous functions of autophagy broadly impact tumorigenesis.