title: Hypoxic activation of the PERK/eIF2α arm of the unfolded protein response promotes metastasis through induction of LAMP3.
abstract: OBJECTIVE
  Conditions of poor oxygenation (hypoxia) are present in many human tumors, including cervix cancer, and are associated with increased risk of metastasis and poor prognosis. Hypoxia is a potent activator of the PERK/eIF2α signaling pathway, a component of the unfolded protein response (UPR) and an important mediator of hypoxia tolerance and tumor growth. Here, the importance of this pathway in the metastasis of human cervix carcinoma was investigated.
  
  
  METHODS
  Amplification and expression of LAMP3, a UPR metastasis-associated gene, was examined using FISH and immunofluorescence in a cohort of human cervix tumors from patients who had received oxygen needle electrode tumor oxygenation measurements. To evaluate the importance of this pathway in metastasis in vivo, we constructed a series of inducible cell lines to interfere with PERK signaling during hypoxia and used these in an orthotopic cervix cancer model of hypoxia-driven metastasis.
  
  
  RESULTS
  We show that LAMP3 expression in human cervix tumors is augmented both by gene copy number alterations and by hypoxia. Induced disruption of PERK signaling in established orthotopic xenografts resulted in complete inhibition of hypoxia-induced metastasis to the lymph nodes. This is due, in part, to a direct influence of the UPR pathway on hypoxia tolerance. However, we also find that LAMP3 is a key mediator of hypoxia-driven nodal metastasis, through its ability to promote metastatic properties including cell migration.
  
  
  CONCLUSIONS
  These data suggest that the association between hypoxia, metastasis, and poor prognosis is due, in part, to hypoxic activation of the UPR and expression of LAMP3. Clin Cancer Res; 19(22); 6126-37. ©2013 AACR.
authors.affiliation: Authors' Affiliations: Ontario Cancer Institute and Campbell Family Institute for Cancer Research, Princess Margaret Cancer Centre, University Health Network; Departments of Laboratory Medicine and Pathobiology, Radiation Oncology, and Medical Biophysics; Radiation Medicine Program, Department of Biostatistics, Princess Margaret Cancer Centre, Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Maastricht Radiation Oncology (MaastRO) Lab, GROW - School for Oncology and Developmental Biology, Maastricht University, Maastricht; and Departments of Radiation Oncology and Laboratory Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
authors.forename: Hilda
authors.initials: H
authors.lastname: Mujcic
authors.forename: Anika
authors.initials: A
authors.lastname: Nagelkerke
authors.forename: Kasper M A
authors.initials: KM
authors.lastname: Rouschop
authors.forename: Stephen
authors.initials: S
authors.lastname: Chung
authors.forename: Naz
authors.initials: N
authors.lastname: Chaudary
authors.forename: Paul N
authors.initials: PN
authors.lastname: Span
authors.forename: Blaise
authors.initials: B
authors.lastname: Clarke
authors.forename: Michael
authors.initials: M
authors.lastname: Milosevic
authors.forename: Jenna
authors.initials: J
authors.lastname: Sykes
authors.forename: Richard P
authors.initials: RP
authors.lastname: Hill
authors.forename: Marianne
authors.initials: M
authors.lastname: Koritzinsky
authors.forename: Bradly G
authors.initials: BG
authors.lastname: Wouters
mesh_terms: D000818:Animals; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002465:Cell Movement; D056915:DNA Copy Number Variations; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D005260:Female; D018628:Gene Dosage; D006801:Humans; D008207:Lymphatic Metastasis / Q000235:genetics / Q000473:pathology*; D051907:Lysosomal Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009368:Neoplasm Transplantation; D054645:Protein Phosphatase 1 / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D014183:Transplantation, Heterologous; D056811:Unfolded Protein Response / Q000502:physiology*; D002583:Uterine Cervical Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality; D019892:eIF-2 Kinase / Q000378:metabolism; D059666:Lysosomal-Associated Membrane Protein 3
chemical_list: D015852:Eukaryotic Initiation Factor-2; D051907:Lysosomal Membrane Proteins; D009363:Neoplasm Proteins; D054645:Protein Phosphatase 1; D019892:eIF-2 Kinase; C114233:LAMP3 protein, human; D059666:Lysosomal-Associated Membrane Protein 3; C460640:EIF2AK3 protein, human; C513256:Ppp1r15a protein, mouse