Proteome profiling of exosomes derived from human primary and metastatic colorectal cancer cells reveal differential expression of key metastatic factors and signal transduction components

Proteomics. 2013 May;13(10-11):1672-86. doi: 10.1002/pmic.201200562.

Abstract

Exosomes are small extracellular 40-100 nm diameter membrane vesicles of late endosomal origin that can mediate intercellular transfer of RNAs and proteins to assist premetastatic niche formation. Using primary (SW480) and metastatic (SW620) human isogenic colorectal cancer cell lines we compared exosome protein profiles to yield valuable insights into metastatic factors and signaling molecules fundamental to tumor progression. Exosomes purified using OptiPrep™ density gradient fractionation were 40-100 nm in diameter, were of a buoyant density ~1.09 g/mL, and displayed stereotypic exosomal markers TSG101, Alix, and CD63. A major finding was the selective enrichment of metastatic factors (MET, S100A8, S100A9, TNC), signal transduction molecules (EFNB2, JAG1, SRC, TNIK), and lipid raft and lipid raft-associated components (CAV1, FLOT1, FLOT2, PROM1) in exosomes derived from metastatic SW620 cells. Additionally, using cryo-electron microscopy, ultrastructural components in exosomes were identified. A key finding of this study was the detection and colocalization of protein complexes EPCAM-CLDN7 and TNIK-RAP2A in colorectal cancer cell exosomes. The selective enrichment of metastatic factors and signaling pathway components in metastatic colon cancer cell-derived exosomes contributes to our understanding of the cross-talk between tumor and stromal cells in the tumor microenvironment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium-Binding Proteins / metabolism
  • Calgranulin A / metabolism
  • Calgranulin B / metabolism
  • Cell Line, Tumor
  • Cell Proliferation
  • Colorectal Neoplasms
  • Endothelial Cells / physiology
  • Ephrin-B2 / metabolism
  • ErbB Receptors / metabolism
  • Exosomes / pathology
  • Exosomes / physiology*
  • Germinal Center Kinases
  • Humans
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Jagged-1 Protein
  • Membrane Microdomains / metabolism
  • Membrane Proteins / metabolism
  • Mice
  • Neoplasm Metastasis
  • Protein-Serine-Threonine Kinases / metabolism
  • Proteome / metabolism*
  • Serrate-Jagged Proteins
  • Signal Transduction*
  • Tenascin / metabolism
  • src-Family Kinases / metabolism

Substances

  • Calcium-Binding Proteins
  • Calgranulin A
  • Calgranulin B
  • Ephrin-B2
  • Germinal Center Kinases
  • Intercellular Signaling Peptides and Proteins
  • JAG1 protein, human
  • Jag1 protein, mouse
  • Jagged-1 Protein
  • Membrane Proteins
  • Proteome
  • Serrate-Jagged Proteins
  • Tenascin
  • EGFR protein, human
  • ErbB Receptors
  • src-Family Kinases
  • Protein-Serine-Threonine Kinases
  • TNIK protein, human