1PD - Breast cancer blood-derived exosomes: Characterisation of protein composition in search for new biomarkers

Date 17 December 2016
Event ESMO Asia 2016 Congress
Session Basic science and translational research
Topics Basic Science
Breast Cancer
Presenter Oleg Tutanov
Citation Annals of Oncology (2016) 27 (suppl_9): ix1-ix8. 10.1093/annonc/mdw573
Authors O.S. Tutanov1, S.N. Tamkovich1, A. Grigoryeva2, E. Ryabchikova2, T. Duzhak3, Y. Tsentalovich3, P. Laktionov1, V. Vlassov1
  • 1Laboratory Of Molecular Medicine, Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 - Novosibirsk/RU
  • 2Group Of Microscopy, Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 - Novosibirsk/RU
  • 3Group Of Proteomics And Metabolomics, International Tomography Center SB RAS, 630090 - Novosibirsk/RU

Abstract

Background

Exosomes are known to be involved in the signalling processes and cell-to-cell communication both in healthy organisms and during the development of various cancer types. However, the exact mechanisms of sorting and secreting as well as the circulation patterns and composition of exosomes are still unclear. The aim of our research is to identify protein content of blood-derived exosomes and determine potential biomarkers specific for breast cancer development. Since exosomes are naturally binding with the cells, we decided to extract them not only from blood plasma but also from blood cells surface in order to understand their percentage, properties and composition.

Methods

Exosomes from blood plasma and blood cell surface-bound exosomes were obtained using methods developed in our lab (RF Patent #2556825, #2571507). The resultant samples were characterized by transmission electron microscopy (TEM) and immunogold labeling to state the presence of characteristic exosome tetraspanins CD-9, CD-24 and CD-63. Proteins from exosome samples were separated by electrophoresis in gradient polyacrylamide gel and identified by MALDI-TOF analysis.

Results

Immunogold labeling confirmed the presence of antigens characteristic for exosomes: CD-9, CD-24 and CD-63. The evaluation of particle diameter of 14 950 exosomes has shown that the blood of breast cancer patients is mostly presented with exosomes diameter from 50 to 70 nm, the blood of healthy women - from 30 to 50 nm. We discovered that 61% of blood-derived exosomes are bound to the surface of blood cells. MALDI TOF/TOF identified more than 150 proteins in exosomes from the blood of healthy women (n = 5) and breast cancer patients (n = 5), the majority of which are found in exosomes for the first time (according Exocarta database at the summer of 2016).

Conclusions

Although it is still unclear what leads to differences in exosome size in plasma and on the surface of the blood cells the results suggest the importance of this exosome fraction and provides us with the new perspective in exosome research. Further analysis with expanded sample size may lead us to biomarker patterns as well as new insight into exosome structure.

Clinical trial indentification

Legal entity responsible for the study

Laboratory of Molecular Medicine, Institute of Chemical Biology and Fundamental Medicine of Siberian Branch of Russian Academy of Sciences

Funding

Russian Foundation for Fundamental Research grant

Disclosure

All authors have declared no conflicts of interest.