Oncogenic ras-driven cancer cell vesiculation leads to emission of double-stranded DNA capable of interacting with target cells

Biochem Biophys Res Commun. 2014 Aug 22;451(2):295-301. doi: 10.1016/j.bbrc.2014.07.109. Epub 2014 Jul 30.

Abstract

Cell free DNA is often regarded as a source of genetic cancer biomarkers, but the related mechanisms of DNA release, composition and biological activity remain unclear. Here we show that rat epithelial cell transformation by the human H-ras oncogene leads to an increase in production of small, exosomal-like extracellular vesicles by viable cancer cells. These EVs contain chromatin-associated double-stranded DNA fragments covering the entire host genome, including full-length H-ras. Oncogenic N-ras and SV40LT sequences were also found in EVs emitted from spontaneous mouse brain tumor cells. Disruption of acidic sphingomyelinase and the p53/Rb pathway did not block emission of EV-related oncogenic DNA. Exposure of non-transformed RAT-1 cells to EVs containing mutant H-ras DNA led to the uptake and retention of this material for an extended (30days) but transient period of time, and stimulated cell proliferation. Thus, our study suggests that H-ras-mediated transformation stimulates vesicular emission of this histone-bound oncogene, which may interact with non-transformed cells.

Keywords: Chromatin; DNA; Extracellular vesicle; Oncogene; Ras; Sphingomyelinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Polyomavirus Transforming / genetics
  • Cell Line
  • Cell Line, Tumor
  • Cell Transformation, Neoplastic / genetics*
  • Cell Transformation, Neoplastic / metabolism
  • Chromatin / genetics
  • Chromatin / metabolism
  • DNA / genetics
  • DNA / metabolism*
  • DNA, Neoplasm / genetics
  • DNA, Neoplasm / metabolism*
  • Exosomes / genetics
  • Exosomes / metabolism
  • Exosomes / ultrastructure
  • Genes, ras*
  • Genome, Human
  • Humans
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / ultrastructure
  • Mice
  • Microscopy, Electron, Transmission
  • Mutation
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Rats
  • Sphingomyelin Phosphodiesterase / deficiency
  • Sphingomyelin Phosphodiesterase / genetics
  • Sphingomyelin Phosphodiesterase / metabolism

Substances

  • Antigens, Polyomavirus Transforming
  • Chromatin
  • DNA, Neoplasm
  • DNA
  • Sphingomyelin Phosphodiesterase
  • HRAS protein, human
  • Proto-Oncogene Proteins p21(ras)