Proteomic Analysis of Exosomes From Mutant KRAS Colon Cancer Cells Identifies Intercellular Transfer of Mutant KRAS

Mol Cell Proteomics. 2013 Feb;12(2):343-55. doi: 10.1074/mcp.M112.022806. Epub 2012 Nov 15.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alleles
  • Cell Line, Tumor
  • Cell Proliferation
  • Chromatography, Liquid
  • Colonic Neoplasms / chemistry*
  • Colonic Neoplasms / genetics
  • Colonic Neoplasms / metabolism
  • Colonic Neoplasms / pathology*
  • Exosomes / chemistry*
  • Exosomes / metabolism
  • Humans
  • Mutation
  • Neoplasm Invasiveness*
  • Neoplasm Proteins / chemistry*
  • Neoplasm Proteins / metabolism
  • Protein Transport
  • Proteome / chemistry*
  • Proteome / metabolism
  • Proto-Oncogene Proteins / chemistry*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins p21(ras)
  • Signal Transduction
  • Tandem Mass Spectrometry
  • Tumor Microenvironment
  • ras Proteins / chemistry*
  • ras Proteins / genetics
  • ras Proteins / metabolism

Substances

  • KRAS protein, human
  • Neoplasm Proteins
  • Proteome
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins p21(ras)
  • ras Proteins