2021 Fiscal Year Research-status Report
Identification of early stage malignancy changes in the structural and biophysical proporties of exosomes by atomic force microscopy (AFM)-based nano-mechanical measurements
| Project/Area Number |
20K05321
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| Research Institution | Kanazawa University |
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Principal Investigator |
YURTSEVER AYHAN 金沢大学, ナノ生命科学研究所, 特任助教 (00761529)
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| Project Period (FY) |
2020-04-01 – 2024-03-31
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| Keywords | Exosomes / 3D-AFM / Nanomechanics / Cell |
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| Outline of Annual Research Achievements |
We applied 3D-AFM to assess the structural and nanomechanical properties of exosomes released from three types of cells in a physiologically relevant environment. The 3D-AFM force maps enabled previously unidentified substructures of individual exosomes to be observed, indicating the presence of distinct nanodomains bulging out from the membrane surface. These protruding features were attributed to membrane-associated proteins exposed on the outer surface. We revealed malignancy state-dependent changes in the mechanical properties of exosomes and their parent cells, and our results showed differences between the nanomechanical properties of metastatic and nonmetastatic tumor cell-derived exosomes. Highly aggressive metastatic 143B cell-derived exosomes exhibited an increased Young’s modulus, 192 MPa, compared with 118 MPa for nonmetastatic HOS cell-derived exosomes. We further examined the mechanical properties of the parent cells that secrete HOS and 143B exosomes. The results showed a decrease in the Young’s modulus of 143B cells compared to that of HOS cells, confirming widely accepted results. Cell-based ELISA indicated that the elastic-fiber associated proteins;which were highly expressed in 143B exosomes;were significantly less expressed in metastatic parent 143B cells than in nonmetastatic HOS cells. Our findings thus suggest that metastatic tumor cells may preserve their softness by releasing certain proteins through exosomes. Our findings thus suggest that metastatic tumor cells may preserve their softness by releasing certain proteins through exosomes.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Research progress is sufficient.
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| Strategy for Future Research Activity |
The biochemical composition of exosomes will be determined using functionalized AFM probes with biomolecules specific to exosome surface receptors and proteins. Furthermore, we are planning to investigate the distribution of phosphatidylserine (PS) on the exosome surface by using PS-binding proteins.
The adhesion forces acting between functionalized tips and specific molecular recognition sites present on exosome surfaces will be measured for both normal and cancer-derived exosomes. This will allow us mapping of the distribution of surface receptors, proteins, etc. This is a crucial step for the determination of compositional differences between normal and cancer-derived exosomes.
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| Causes of Carryover |
We just changed our plan.
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