title: Amphiregulin exosomes increase cancer cell invasion.
abstract: Autocrine, paracrine, and juxtacrine are recognized modes of action for mammalian EGFR ligands including EGF, TGF-α (TGFα), amphiregulin (AREG), heparin-binding EGF-like growth factor (HB-EGF), betacellulin, epiregulin, and epigen. We identify a new mode of EGFR ligand signaling via exosomes. Human breast and colorectal cancer cells release exosomes containing full-length, signaling-competent EGFR ligands. Exosomes isolated from MDCK cells expressing individual full-length EGFR ligands displayed differential activities; AREG exosomes increased invasiveness of recipient breast cancer cells 4-fold over TGFα or HB-EGF exosomes and 5-fold over equivalent amounts of recombinant AREG. Exosomal AREG displayed significantly greater membrane stability than TGFα or HB-EGF. An average of 24 AREG molecules are packaged within an individual exosome, and AREG exosomes are rapidly internalized by recipient cells. Whether the composition and behavior of exosomes differ between nontransformed and transformed cells is unknown. Exosomes from DLD-1 colon cancer cells with a mutant KRAS allele exhibited both higher AREG levels and greater invasive potential than exosomes from isogenically matched, nontransformed cells in which mutant KRAS was eliminated by homologous recombination. We speculate that EGFR ligand signaling via exosomes might contribute to diverse cancer phenomena such as field effect and priming of the metastatic niche.
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: James N
authors.initials: JN
authors.lastname: Higginbotham
authors.forename: Michelle
authors.initials: M
authors.lastname: Demory Beckler
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Gephart
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Franklin
authors.forename: Galina
authors.initials: G
authors.lastname: Bogatcheva
authors.forename: Gert-Jan
authors.initials: GJ
authors.lastname: Kremers
authors.forename: David W
authors.initials: DW
authors.lastname: Piston
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Ayers
authors.forename: Russell E
authors.initials: RE
authors.lastname: McConnell
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Tyska
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Coffey
mesh_terms: D066258:Amphiregulin; D000818:Animals; D045744:Cell Line, Tumor; D002498:Centrifugation; D004285:Dogs; D066255:EGF Family of Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D066246:ErbB Receptors / Q000378:metabolism*; D055354:Exosomes / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D015151:Immunoblotting; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D008854:Microscopy, Electron; D009361:Neoplasm Invasiveness / Q000503:physiopathology*; D015398:Signal Transduction / Q000502:physiology*; D016211:Transforming Growth Factor alpha / Q000378:metabolism
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; D006023:Glycoproteins; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D016211:Transforming Growth Factor alpha; D066246:ErbB Receptors