title: PERK integrates autophagy and oxidative stress responses to promote survival during extracellular matrix detachment.
abstract: Mammary epithelial cells (MECs) detached from the extracellular matrix (ECM) produce deleterious reactive oxygen species (ROS) and induce autophagy to survive. The coordination of such opposing responses likely dictates whether epithelial cells survive ECM detachment or undergo anoikis. Here, we demonstrate that the endoplasmic reticulum kinase PERK facilitates survival of ECM-detached cells by concomitantly promoting autophagy, ATP production, and an antioxidant response. Loss-of-function studies show that ECM detachment activates a canonical PERK-eukaryotic translation initiation factor 2α (eIF2α)-ATF4-CHOP pathway that coordinately induces the autophagy regulators ATG6 and ATG8, sustains ATP levels, and reduces ROS levels to delay anoikis. Inducible activation of an Fv2E-ΔNPERK chimera by persistent activation of autophagy and reduction of ROS results in lumen-filled mammary epithelial acini. Finally, luminal P-PERK and LC3 levels are reduced in PERK-deficient mammary glands, whereas they are increased in human breast ductal carcinoma in situ (DCIS) versus normal breast tissues. We propose that the normal proautophagic and antioxidant PERK functions may be hijacked to promote the survival of ECM-detached tumor cells in DCIS lesions.
authors.affiliation: Department of Medicine, Tisch Cancer Institute, Black Family Stem Cell Institute, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Avivar-Valderas
authors.forename: Eduardo
authors.initials: E
authors.lastname: Salas
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Bobrovnikova-Marjon
authors.forename: J Alan
authors.initials: JA
authors.lastname: Diehl
authors.forename: Chandandeep
authors.initials: C
authors.lastname: Nagi
authors.forename: Jayanta
authors.initials: J
authors.lastname: Debnath
authors.forename: Julio A
authors.initials: JA
authors.lastname: Aguirre-Ghiso
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001343:Autophagy / Q000502:physiology*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion; D002460:Cell Line; D002470:Cell Survival; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology; D004789:Enzyme Activation; D005109:Extracellular Matrix / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008321:Mammary Glands, Animal / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D034622:RNA Interference; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism*
chemical_list: D000255:Adenosine Triphosphate; D049452:Green Fluorescent Proteins; D008869:Microtubule-Associated Proteins; D019892:eIF-2 Kinase; C477012:MAP1LC3A protein, human