title: Proteomic analysis of exosomes from mutant KRAS colon cancer cells identifies intercellular transfer of mutant KRAS.
abstract: Activating mutations in KRAS occur in 30% to 40% of colorectal cancers. How mutant KRAS alters cancer cell behavior has been studied intensively, but non-cell autonomous effects of mutant KRAS are less understood. We recently reported that exosomes isolated from mutant KRAS-expressing colon cancer cells enhanced the invasiveness of recipient cells relative to exosomes purified from wild-type KRAS-expressing cells, leading us to hypothesize mutant KRAS might affect neighboring and distant cells by regulating exosome composition and behavior. Herein, we show the results of a comprehensive proteomic analysis of exosomes from parental DLD-1 cells that contain both wild-type and G13D mutant KRAS alleles and isogenically matched derivative cell lines, DKO-1 (mutant KRAS allele only) and DKs-8 (wild-type KRAS allele only). Mutant KRAS status dramatically affects the composition of the exosome proteome. Exosomes from mutant KRAS cells contain many tumor-promoting proteins, including KRAS, EGFR, SRC family kinases, and integrins. DKs-8 cells internalize DKO-1 exosomes, and, notably, DKO-1 exosomes transfer mutant KRAS to DKs-8 cells, leading to enhanced three-dimensional growth of these wild-type KRAS-expressing non-transformed cells. These results have important implications for non-cell autonomous effects of mutant KRAS, such as field effect and tumor progression.
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Demory Beckler
authors.forename: James N
authors.initials: JN
authors.lastname: Higginbotham
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Franklin
authors.forename: Amy-Joan
authors.initials: AJ
authors.lastname: Ham
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Halvey
authors.forename: Imade E
authors.initials: IE
authors.lastname: Imasuen
authors.forename: Corbin
authors.initials: C
authors.lastname: Whitwell
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Liebler
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Coffey
mesh_terms: D000483:Alleles; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002853:Chromatography, Liquid; D003110:Colonic Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D055354:Exosomes / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D009154:Mutation; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000378:metabolism; D021381:Protein Transport; D020543:Proteome / Q000737:chemistry* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras); D015398:Signal Transduction; D053719:Tandem Mass Spectrometry; D059016:Tumor Microenvironment; D018631:ras Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: C117307:KRAS protein, human; D009363:Neoplasm Proteins; D020543:Proteome; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins