Nanoparticles in 472 Human Cerebrospinal Fluid: Changes in Extracellular Vesicle Concentration and miR-21 Expression as a Biomarker for Leptomeningeal Metastasis

Abstract

Leptomeningeal metastasis (LM) has a poor prognosis and is difficult to diagnose and predict the response of treatment. In this study, we suggested that the monitoring of changes in the concentration of extracellular vesicles in cerebrospinal fluid could help diagnose or predict outcomes for LM. We measured nanoparticles in 472 human cerebrospinal fluid (CSF) from patients including LM with both Dynamic Light Scattering (DLS) and Nanoparticle Tracking Analysis (NTA) after two-step centrifugations. NTA revealed that the concentration of CSF nanoparticles was significantly increased in LM compared to other groups (2.80 × 108 /mL vs. 1.49 × 108 /mL, p < 0.01). Changes in NTA-measured nanoparticles concentration after intra-CSF chemotherapy were further examined in 33 non-small cell lung cancer patients with LM. Overall survival was longer for patients with increased EV than the others (442 vs. 165 days, p < 0.001). Markers of extracellular vesicles (CD9/CD63/CD81) significantly decreased in the EV-decreased group. MicroRNA-21 expression decreased in this favorable prognostic group, whereas it increased in the EV-decreased group. In conclusion, the elevated concentration of extracellular vesicles in cerebrospinal fluid in patients with LM may be a predictive marker for survival duration. Moreover, EV changes combined with microRNA-21 might be a biomarker for monitoring the efficacy of intracranial chemotherapy of LM in non-small cell lung cancer patients.

Exosome Processing and Characterization Approaches for Research and Technology Development

“…Two challenges in characterizing exosomes in the context of neurodegenerative diseases are the limited sample volume of CSF and the abundance of nanoparticles in CSF that are similar to exosomes in size and density, [ 270 ] contaminate isolated exosome samples, and cannot be distinguished by NTA. [ 271 ] Novel methods have been developed to address these challenges.…”

The role of extracellular vesicles in the physiological and pathological regulation of the blood–brain barrier

“…GBM-patient serum samples (36). Similarly, miR-21 was consistently found to be enriched in EVs isolated from blood samples of patients affected by GBM (36, 74) as well as from the CSF of patients with leptomeningeal metastasis (75). Interestingly, miR-21was also found to be enriched in EVs isolated from brains of murine models of traumatic brain injury where the brain trauma was mimicked with a craniotomy followed by a controlled damage of the dura (76).…”

From Molecular Mechanisms to Therapeutics: Understanding MicroRNA-21 in Cancer

“…MiR-21 may even be useful in rare cancers with few available biomarkers. In leptomeningeal metastasis (LM) patients, miR-21 expression was monitored using EVs extracted from cerebrospinal fluid (CSF) and found that aberrant miR-21 expression correlated with patient survival [ 112 , 113 , 114 ].…”

“…Current evidence demonstrates that miR-21 exerts immense influence on cancer progression, including strong effects on cancer cell proliferation, stemness, apoptosis, and chemoresistance. In addition, circulating miR-21 can not only be used as a diagnostic tool but also as a targetable functional component of systemic intercellular communication in cancers such as GBM and LM [ 108 , 112 ]. Although the ability to predict interactions and create therapeutic avenues for inhibiting miR-21 has advanced significantly in the past decade, complications related to cancer heterogeneity and the intricate web of the microenvironment itself have become increasingly apparent.…”