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
|Citation||Annals of Oncology (2016) 27 (suppl_9): ix1-ix8. 10.1093/annonc/mdw573|
O.S. Tutanov1, S.N. Tamkovich1, A. Grigoryeva2, E. Ryabchikova2, T. Duzhak3, Y. Tsentalovich3, P. Laktionov1, V. Vlassov1
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.
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.
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).
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
Russian Foundation for Fundamental Research grant
All authors have declared no conflicts of interest.