Hypoxia Induced ER Stress Response as an Adaptive Mechanism in Cancer

It is evident that regions within tumors are deprived of oxygen, which makes the microenvironment hypoxic. Cancer cells experiencing hypoxia undergo metabolic alterations and cytoprotective adaptive mechanisms to survive such stringent conditions. While such mechanisms provide potential therapeutic targets, the mechanisms by which hypoxia regulates adaptive responsessuch as ER stress response, unfolded protein response (UPR), anti-oxidative responses, and autophagyremain elusive. In this review, we summarize the complex interplay between hypoxia and the ER stress signaling pathways that are activated in the hypoxic microenvironment of the tumors.