title: Pancreatic Cancer-Derived Exosomes Cause Paraneoplastic β-cell Dysfunction.
abstract: OBJECTIVE
  Pancreatic cancer frequently causes diabetes. We recently proposed adrenomedullin as a candidate mediator of pancreatic β-cell dysfunction in pancreatic cancer. How pancreatic cancer-derived adrenomedullin reaches β cells remote from the cancer to induce β-cell dysfunction is unknown. We tested a novel hypothesis that pancreatic cancer sheds adrenomedullin-containing exosomes into circulation, which are transported to β cells and impair insulin secretion.
  
  
  METHODS
  We characterized exosomes from conditioned media of pancreatic cancer cell lines (n = 5) and portal/peripheral venous blood of patients with pancreatic cancer (n = 20). Western blot analysis showed the presence of adrenomedullin in pancreatic cancer-exosomes. We determined the effect of adrenomedullin-containing pancreatic cancer exosomes on insulin secretion from INS-1 β cells and human islets, and demonstrated the mechanism of exosome internalization into β cells. We studied the interaction between β-cell adrenomedullin receptors and adrenomedullin present in pancreatic cancer-exosomes. In addition, the effect of adrenomedullin on endoplasmic reticulum (ER) stress response genes and reactive oxygen/nitrogen species generation in β cells was shown.
  
  
  RESULTS
  Exosomes were found to be the predominant extracellular vesicles secreted by pancreatic cancer into culture media and patient plasma. Pancreatic cancer-exosomes contained adrenomedullin and CA19-9, readily entered β cells through caveolin-mediated endocytosis or macropinocytosis, and inhibited insulin secretion. Adrenomedullin in pancreatic cancer exosomes interacted with its receptor on β cells. Adrenomedullin receptor blockade abrogated the inhibitory effect of exosomes on insulin secretion. β cells exposed to adrenomedullin or pancreatic cancer exosomes showed upregulation of ER stress genes and increased reactive oxygen/nitrogen species.
  
  
  CONCLUSIONS
  Pancreatic cancer causes paraneoplastic β-cell dysfunction by shedding adrenomedullin(+)/CA19-9(+) exosomes into circulation that inhibit insulin secretion, likely through adrenomedullin-induced ER stress and failure of the unfolded protein response.
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Naureen
authors.initials: N
authors.lastname: Javeed
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Gunisha
authors.initials: G
authors.lastname: Sagar
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Shamit K
authors.initials: SK
authors.lastname: Dutta
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Smyrk
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Julie S
authors.initials: JS
authors.lastname: Lau
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Santanu
authors.initials: S
authors.lastname: Bhattacharya
authors.affiliation: Department of Surgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Mark
authors.initials: M
authors.lastname: Truty
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors.forename: Gloria M
authors.initials: GM
authors.lastname: Petersen
authors.affiliation: Degenerative Disease Research Program, Sanford Burnham Medical Research Institute, La Jolla, California.
authors.forename: Randal J
authors.initials: RJ
authors.lastname: Kaufman
authors.affiliation: Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota. mukhopadhyay.debabrata@mayo.edu chari.suresh@mayo.edu.
authors.forename: Suresh T
authors.initials: ST
authors.lastname: Chari
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota. mukhopadhyay.debabrata@mayo.edu chari.suresh@mayo.edu.
authors.forename: Debabrata
authors.initials: D
authors.lastname: Mukhopadhyay
mesh_terms: D053607:Adrenomedullin / Q000378:metabolism*; D015153:Blotting, Western; D018395:CA-19-9 Antigen / Q000378:metabolism; D003920:Diabetes Mellitus / Q000209:etiology*; D055354:Exosomes / Q000378:metabolism*; D006801:Humans; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D018613:Microscopy, Confocal; D010190:Pancreatic Neoplasms / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D010257:Paraneoplastic Syndromes / Q000209:etiology / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D018395:CA-19-9 Antigen; D053607:Adrenomedullin