Abstract
Extracellular vesicles (EVs) represent a diverse group of small membrane-encapsulated particles involved in cell–cell communication, but the technologies to characterize EVs are still limited. Hypoxia is a typical condition in solid tumors, and cancer-derived EVs support tumor growth and invasion of tissues by tumor cells. We found that exposure of renal adenocarcinoma cells to hypoxia induced EV secretion and led to notable changes in the EV protein cargo in comparison to normoxia. Proteomics analysis showed overrepresentation of proteins involved in adhesion, such as integrins, in hypoxic EV samples. We further assessed the efficacy of time-gated Raman spectroscopy (TG-RS) and surface-enhanced time-gated Raman spectroscopy (TG-SERS) to characterize EVs. While the conventional continuous wave excitation Raman spectroscopy did not provide a notable signal, prominent signals were obtained with the TG-RS that were further enhanced in the TG-SERS. The Raman signal showed characteristic changes in the amide regions due to alteration in the chemical bonds of the EV proteins. The results illustrate that the TG-RS and the TG-SERS are promising label free technologies to study cellular impact of external stimuli, such as oxygen deficiency, on EV production, as well as differences arising from distinct EV purification protocols.
| Original language | English |
|---|---|
| Article number | 19594 |
| Pages (from-to) | 19594 |
| Journal | Scientific Reports |
| Volume | 11 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Oct 2021 |
| MoE publication type | A1 Journal article-refereed |
Funding
The work is part of the Academy of Finland (AF) Flagship Programs: Photonics Research and Innovation (PREIN) with decisions 320168 (M.K., J.H) and 320166 (S.A., M.R) and Gene, Cell and Nano Therapy Competence Cluster for the Treatment of Chronic Diseases (GeneCellNano) with decisions 337431 (S.V., A.S., G.B.) and 315030 (S.V.). The work by Univ. Oulu and VTT groups was partially funded by FET Open MindGap-project (EU Grant agreement ID: 829040). The study was supported by the grants from Cancer Foundation of Finland to S.V. (2017 and 2018), Business Finland Future of Diagnostics—FUDIS, and EDUFI (Finnish National Agency for Education) Fellowships. We thank Ilkka Miinalainen, Mika Kaakinen and Biocenter Oulu Electron Microscopy core facility, Ulrich Bergmann and Biocenter Oulu Mass spectrometry core facility, and Fabienne Wagner.
