Background: Extracellular vesicles (EVs) are secreted membranous particles intensively studied for their potential cargo of diagnostic markers. Efficient and cost-effective isolation methods need to be established for the reproducible and high-throughput study of EVs in the clinical practice. Methods: We designed the nickel-based isolation (NBI) to rapidly isolate EVs and combined it with newlydesigned amplified luminescent proximity homogeneous assay or digital PCR to detect biomarkers of clinical utility. Findings: From plasma of 46 healthy donors, we systematically recovered small EV (~250 nm of mean diameter; ~3 × 10^10/ml) and large EV (~560 nm of mean diameter; ~5 × 10^8/ml) lineages ranging from 50 to 700 nm, which displayed hematopoietic/endothelial cell markers that were also used in spike-in experiments using EVs from tumor cell lines. In retrospective studies, we detected picomolar concentrations of prostate-specific membrane antigen (PSMA) in fractions of EVs isolated from the plasma of prostate cancer patients, discriminating them from control subjects. Directly from oil-encapsulated EVs for digital PCR, we identified somatic BRAF and KRAS mutations circulating in the plasma of metastatic colorectal cancer (CRC) patients, matching 100% of concordance with tissue diagnostics. Importantly, with higher sensitivity and specificity compared with immuno-isolated EVs, we revealed additional somatic alterations in 7% of wild-type CRC cases that were subsequently validated by further inspections in the matched tissue biopsies. Interpretation: We propose NBI-combined approaches as simple, fast, and robust strategies to probe the tumor heterogeneity and contribute to the development of EV-based liquid biopsy studies.

Ultrasensitive detection of cancer biomarkers by nickel-based isolation of polydisperse extracellular vesicles from blood

Scarduelli, Giorgina;Potrich, Cristina;Lunelli, Lorenzo;Pederzolli, Cecilia;
2019

Abstract

Background: Extracellular vesicles (EVs) are secreted membranous particles intensively studied for their potential cargo of diagnostic markers. Efficient and cost-effective isolation methods need to be established for the reproducible and high-throughput study of EVs in the clinical practice. Methods: We designed the nickel-based isolation (NBI) to rapidly isolate EVs and combined it with newlydesigned amplified luminescent proximity homogeneous assay or digital PCR to detect biomarkers of clinical utility. Findings: From plasma of 46 healthy donors, we systematically recovered small EV (~250 nm of mean diameter; ~3 × 10^10/ml) and large EV (~560 nm of mean diameter; ~5 × 10^8/ml) lineages ranging from 50 to 700 nm, which displayed hematopoietic/endothelial cell markers that were also used in spike-in experiments using EVs from tumor cell lines. In retrospective studies, we detected picomolar concentrations of prostate-specific membrane antigen (PSMA) in fractions of EVs isolated from the plasma of prostate cancer patients, discriminating them from control subjects. Directly from oil-encapsulated EVs for digital PCR, we identified somatic BRAF and KRAS mutations circulating in the plasma of metastatic colorectal cancer (CRC) patients, matching 100% of concordance with tissue diagnostics. Importantly, with higher sensitivity and specificity compared with immuno-isolated EVs, we revealed additional somatic alterations in 7% of wild-type CRC cases that were subsequently validated by further inspections in the matched tissue biopsies. Interpretation: We propose NBI-combined approaches as simple, fast, and robust strategies to probe the tumor heterogeneity and contribute to the development of EV-based liquid biopsy studies.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11582/318349
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