Page 135 - SRPSKO DRUŠTVO ISTRAŽIVAČA RAKA

SDIRSACR Oncology Insights

SESSION 8

LIQUID BIOPSY

P41

Basic properties of extracellular vesicles from cerebrospinal fluid of subjects with non-malignant and
malignant neurological disorders

Ninoslav Mitić , Filip Janjić , Ljiljana Vujotić , Sanja Goč , Tamara Janković , Miroslava Janković 1
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1 Institute for the Application of Nuclear Energy – INEP, University of Belgrade, Belgrade, Serbia
2 Clinic for Neurosurgery, University Clinical Center of Serbia, Belgrade, Serbia
Keywords: brain cancer, extracellular vesicles, nanoparticle tracking analysis, sialic acid

Background: Cerebrospinal fluid (CSF) is a clear fluid with low protein content, widely used for both diagnostic and
prognostic purposes. Although extracellular vesicles (EVs), small particles with a bilayer membrane, are present in
CSF, data regarding their properties remain scarce. In this study, EVs were isolated from CSF of subjects with non-
malignant (hydrocephalus) and malignant (medulloblastoma/ependymoma) neurological disorders to compare their
concentration, size distribution, and surface presence of sialic acid-containing glycans. This study aims to provide
preliminary data on the potential of basic CSF EVs properties as discriminating markers.
Material and Methods: EVs were isolated from pooled CSF samples of subjects with non-malignant (nmEVs) and
malignant (mEVs) neurological disorders by differential centrifugation. Fluorescently labeled sialic acid-binding plant
lectins: wheat germ agglutinin (WGA) and Sambucus nigra agglutinin (SNA) were used in nanoparticle tracking analysis
(NTA) to assess EVs surface sialylation. The presence of tetraspanins, commonly used as EVs markers, was evaluated
using antibodies against CD9, CD81, and CD63.
Results: Higher concentration of mEVs (1.08×10¹¹ particles/mL) compared to nmEVs (1.50×10¹⁰ particles/mL) was
revealed. Size distribution showed that the majority of EVs in both subject groups fell within the 100-200 nm range.
The share of CD9-positive EVs was five times higher in nmEVs compared to mEVs, while the share of CD81-positive EVs
did not differ notably between the two groups. Anti-CD63 antibody exhibited minimal reactivity to both nmEVs and
mEVs. The share of WGA-reactive EVs was similar between nmEVs and mEVs, whereas the share of SNA-reactive EVs
was over three times higher in mEVs.
Conclusions: An increased share of SNA-reactive mEVs, indicating changes in sialylation, was found. In addition, a
reduced share of CD9-positive mEVs was observed. Alterations in basic CSF EVs properties may serve as potential
markers of their origin.

Acknowledgments and funding: This work was supported by the Ministry of Science, Innovation and Technological
Development of the Republic of Serbia [Grant No. 451-03-136/2025-03/200019].

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