title: The roles of reactive oxygen species and autophagy in mediating the tolerance of tumor cells to cycling hypoxia.
abstract: Tumor hypoxia (low oxygenation) causes treatment resistance and poor patient outcome. A substantial fraction of tumor cells experience cycling hypoxia, characterized by transient episodes of hypoxia and reoxygenation. These cells are under a unique burden of stress, mediated by excessive production of reactive oxygen species (ROS). Cellular components damaged by ROS can be cleared by autophagy, rendering cycling hypoxic tumor cells particularly vulnerable to inhibition of autophagy and its upstream regulatory pathways. Activation of the PERK-mediated signaling arm of the unfolded protein response during hypoxia plays a critical role in the defense against ROS, both by stimulating glutathione synthesis pathways and through promoting autophagy.
authors.affiliation: Ontario Cancer Institute and Campbell Family Institute for Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Canada; Institute of Medical Science, University of Toronto, Canada. Electronic address: mkoritzi@uhnresearch.ca.
authors.forename: Marianne
authors.initials: M
authors.lastname: Koritzinsky
authors.forename: Bradly G
authors.initials: BG
authors.lastname: Wouters
mesh_terms: D001343:Autophagy / Q000502:physiology* / Q000528:radiation effects; D016923:Cell Death / Q000502:physiology* / Q000528:radiation effects; D015687:Cell Hypoxia / Q000502:physiology* / Q000528:radiation effects; D006801:Humans; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000532:radiotherapy; D018384:Oxidative Stress / Q000502:physiology / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000378:metabolism* / Q000528:radiation effects; D015398:Signal Transduction / Q000502:physiology / Q000528:radiation effects; D059016:Tumor Microenvironment / Q000502:physiology* / Q000528:radiation effects; D019892:eIF-2 Kinase
chemical_list: D017382:Reactive Oxygen Species; D019892:eIF-2 Kinase