Abstract 1922: Selective microfluidic capture and molecular analysis of plasma extracellular vesicles from meningiomas

Abstract: Meningioma (MGM) comprises 39% of all primary intracranial tumors and is classified by the WHO into three grades depending on potential for recurrence. Risk stratification plays a crucial role in determining post-operative therapy and treatment response. Current classifications depend on tumor histology and a small number of genomic markers, though molecular profiling (DNA methylation, copy number, gene expression) may carry higher prognostic value. Minimally invasive liquid biopsy approaches could improve clinical management of MGM by identifying high-risk patients prior to surgery, as well as tumors that have transformed post-operatively. Extracellular vesicles (EVs) are nanometer sized membrane-bound capsules that carry cellular cargo and are abundant in plasma. In this work, we demonstrate the use of a microfluidic based technology (MGMExoChip) to isolate EVs specifically from MGM tissues using a specific protein (MGM-p). Using various characterization methods, we confirmed high capture efficiency and abundant proteins and RNA from 100 µL of plasma. These EVs were isolated from patients with high- and low-grade meningiomas, and then studied using proteomics and mRNA sequencing to identify features that associate with tumor aggression. Methods: MGMExoChip has a polydimethylsiloxane top and a glass bottom. Experiments were performed using MGM cell-line CH157, as well as primary cell cultures and plasma samples collected from MGM patients. Isolated EVs were characterized using nanoparticle tracking analysis, scanning electron microscopy, western blot, and proteomics. RNA extraction was performed using Norgen Biotek kit, sequenced in Illumina platform at 40M raw reads. Data analyses were done using R. Results: MGMExoChip was optimized for flow and capture conditions using EVs harvested from CH157 and two patient-derived primary cell cultures. Using MGM-p-based capture, the capture efficiency of EVs was significantly higher in CH157 relative to lung cancer (A549) (80.5±0.9% vs 6.2±4.2%). Among three antibodies tested for capture (anti-CD63, anti-MGM-p, and annexin-V), western blot confirmed that MGM-p had the highest specificity to isolate MGM EVs. We determined that only 100 µL of plasma was needed to extract an average of 7 µg of proteins and 5 ng of RNA without saturating the device. We further utilized proteomics, and mRNA-seq to explore molecular features that distinguish EVs in low and high grade meningiomas from normal controls among a cohort of 19 plasma samples. Conclusions: The use of microfluidics for liquid biopsy is a novel approach to study meningioma. MGMExoChip isolates MGM-specific EVs from patient plasma that allows extraction of molecular cargo for downstream characterization. Investigation of MGM EVs in a larger cohort could identify promising biomarkers for risk stratification of meningioma and determination of post-operative therapy. Citation Format: Abha Kumari, Harika Lingamarla, Mateo Gomez, Scott Smith, Kathleen McCortney, James Chandler, Craig Horbinski, David Raleigh, Adam Sonabend, Stephen Magill, Mark Youngblood, Sunitha Nagrath. Selective microfluidic capture and molecular analysis of plasma extracellular vesicles from meningiomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1922.