Poster Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

Unrevealed mystery of cell dust:extracellular vesicles and tumor-derived exosomes  (#418)

Deanna Ayupova 1 , Renee Goreham 2 , Paul Teesdale-Spittle 1
  1. Victoria University of Wellington, Wellington, WELLINGTON, New Zealand
  2. Univeristy of Newcastle, Newcastle, Australia

Lung cancer is the leading cause of cancer death. Early diagnosis of cancer is highly desirable, as treatment is more successful with early stage cancers. However, early detection of lung cancer remains a challenge, with most people diagnosed only after the cancer has progressed. Since their discovery as a subset of extracellular vesicles (EVs), exosomes have attracted interest, as they provide potential biomarkers for various diseases including cancer.

The potential of EVs, and especially exosomes, as sources of biomarkers is very high as has been identified through several comparative proteomic analyses of exosomes from different biological fluids (plasma, serum, urine, saliva). Despite the fact that exosomes can serve as supporting evidence in acancer diagnosis, there is no defined and standardized method for isolating and purifying exosomes that gives substantial yield, purity, and optimised protein abundance for proteomic analysis. In this study, we used ultracentrifugation and size-exclusion column-based isolation for exosome isolation from conditioned cell culture medium and exhaled breath condensate. Exosomes characterization was confirmed by transmission electron microscopy (TEM), scanning electron cryomicroscopy (cryoSEM), dynamic light scattering (DLS), immunoblotting, and protein quantification assay. A preliminary proteomic investigation is underway. This approach is the most effective method to isolate exosomes as it keeps vesicles intact. Application of Immunoblotting with gold nanoparticles (AuNP) proved the identification of general (non-specific) markers  for exosomes (tetraspanines CD63 and 81) on the membrane for all isolated exosomes. Finally, we propose that exosomes can be isolated in a non-invasive way from breath, and that these exosomes will contain protein biomarkers that can be used in early detection of lung cancer.