Leukocyte-Derived Extracellular Vesicles in Blood with and without EpCAM Enrichment

Prostate cancer extracellular vesicle digital scoring assay - a rapid noninvasive approach for quantification of disease-relevant mRNAs

Optimizing outcomes in prostate cancer (PCa) requires precision in characterization of disease status. This effort was directed at developing a PCa extracellular vesicle (EV) Digital Scoring Assay (DSA) for detecting metastasis and monitoring progression of PCa. PCa EV DSA is comprised of an EV purification device (i.e., EV Click Chip) and reverse-transcription droplet digital PCR that quantifies 11 PCa-relevant mRNA in purified PCa-derived EVs. A Met score was computed for each plasma sample based on the expression of the 11-gene panel using the weighted Z score method. Under optimized conditions, the EV Click Chips outperformed the ultracentrifugation or precipitation method of purifying PCa-derived EVs from artificial plasma samples. Using PCa EV DSA, the Met score distinguished metastatic (n = 20) from localized PCa (n = 20) with an area under the receiver operating characteristic curve of 0.88 (95% CI:0.78-0.98). Furthermore, longitudinal analysis of three PCa patients showed the dynamics of the Met scores reflected clinical behavior even when disease was undetectable by imaging. Overall, a sensitive PCa EV DSA was developed to identify metastatic PCa and reveal dynamic disease states noninvasively. This assay may complement current imaging tools and blood-based tests for timely detection of metastatic progression that can improve care for PCa patients.

High Blood Concentration of Leukocyte-Derived Extracellular Vesicles Is Predictive of Favorable Clinical Outcomes in Patients with Pancreatic Cancer: Results from a Multicenter Prospective Study

Simple Summary

Blood-circulating extracellular vesicles (EVs) are emerging as key players to develop novel liquid biopsy-based approaches in cancer, including pancreatic cancer. In this study, we aimed to explore the prognostic and predictive value of blood-circulating extracellular vesicles released by immune cells in patients with pancreatic cancer. A recently patented flow cytometry protocol was applied for the identification and phenotypical characterization of blood-circulating EVs in a cohort of 56 patients with pancreatic cancer (PC) and in a group of 48 healthy controls. We observed an increased blood concentration of leukocyte-derived EVs (CD45+) and PD-L1+ EVs in patients with PC as compared to healthy controls. Intriguingly, a high blood concentration of leukocyte-derived EVs identified PC patients with a good prognosis and improved clinical outcomes. This study revealed the promising role of EVs released by immune cells as a source of candidate biomarkers in patients with pancreatic cancer.

Abstract

Pancreatic cancer (PC) is one of the leading causes of cancer-related death worldwide. Identification of novel tumor biomarkers is highly advocated in PC to optimize personalized treatment algorithms. Blood-circulating extracellular vesicles hold promise for liquid biopsy application in cancer. We used an optimized flow cytometry protocol to study leukocyte-derived EVs (CD45+) and PD-L1+ EVs in blood from 56 pancreatic cancer patients and 48 healthy controls (HCs). Our results show that PC patients presented higher blood levels of total EVs (p = 0.0003), leukocyte-derived EVs (LEVs) (p = 0.001) and PD-L1+ EVs (p = 0.01), as compared with HCs. Interestingly, a blood concentration of LEVs at baseline was independently associated with improved overall survival in patients with borderline resectable or primary unresectable PC (HR = 0.17; 95% CI 0.04–0.79; p = 0.02). Additionally, increased blood-based LEVs were independently correlated with prolonged progression-free survival (HR = 0.10; 95% CI 0.01–0.82; p = 0.03) and significantly associated with higher disease control rate (p = 0.02) in patients with advanced PC receiving standard chemotherapy. Notably, a strong correlation between a decrease in blood LEVs concentration during chemotherapy and disease control was observed (p = 0.005). These intriguing findings point to the potential of LEVs as novel blood-based EV biomarkers for improved personalized medicine in patients affected by PC.

Analysis of Amount, Size, Protein Phenotype and Molecular Content of Circulating Extracellular Vesicles Identifies New Biomarkers in Multiple Myeloma

INTRODUCTION

Extracellular vesicles (EVs) are naturally secreted cellular lipid bilayer particles, which carry a selected molecular content. Owing to their systemic availability and their role in tumor pathogenesis, circulating EVs (cEVs) can be a valuable source of new biomarkers useful for tumor diagnosis, prognostication and monitoring. However, a precise approach for isolation and characterization of cEVs as tumor biomarkers, exportable in a clinical setting, has not been conclusively established.

METHODS

We developed a novel and laboratory-made procedure based on a bench centrifuge step which allows the isolation of serum cEVs suitable for subsequent characterization of their size, amount and phenotype by nanoparticle tracking analysis, microscopy and flow cytometry, and for nucleic acid assessment by digital PCR.

RESULTS

Applied to blood from healthy subjects (HSs) and tumor patients, our approach permitted from a small volume of serum (i) the isolation of a great amount of EVs enriched in small vesicles free from protein contaminants; (ii) a suitable and specific cell origin identification of EVs, and (iii) nucleic acid content assessment. In clonal plasma cell malignancy, like multiple myeloma (MM), our approach allowed us to identify specific MM EVs, and to characterize their size, concentration and microRNA content allowing significant discrimination between MM and HSs. Finally, EV associated biomarkers correlated with MM clinical parameters.

CONCLUSION

Overall, our cEV based procedure can play an important role in malignancy biomarker discovery and then in real-time tumor monitoring using minimal invasive samples. From a practical point of view, it is smart (small sample volume), rapid (two hours), easy (no specific expertise required) and requirements are widely available in clinical laboratories.

Large Extracellular Vesicle Characterization and Association with Circulating Tumor Cells in Metastatic Castrate Resistant Prostate Cancer

Liquid biopsies hold potential as minimally invasive sources of tumor biomarkers for diagnosis, prognosis, therapy prediction or disease monitoring. We present an approach for parallel single-object identification of circulating tumor cells (CTCs) and tumor-derived large extracellular vesicles (LEVs) based on automated high-resolution immunofluorescence followed by downstream multiplexed protein profiling. Identification of LEVs >6 µm in size and CTC enumeration was highly correlated, with LEVs being 1.9 times as frequent as CTCs, and additional LEVs were identified in 73% of CTC-negative liquid biopsy samples from metastatic castrate resistant prostate cancer. Imaging mass cytometry (IMC) revealed that 49% of cytokeratin (CK)-positive LEVs and CTCs were EpCAM-negative, while frequently carrying prostate cancer tumor markers including AR, PSA, and PSMA. HSPD1 was shown to be a specific biomarker for tumor derived circulating cells and LEVs. CTCs and LEVs could be discriminated based on size, morphology, DNA load and protein score but not by protein signatures. Protein profiles were overall heterogeneous, and clusters could be identified across object classes. Parallel analysis of CTCs and LEVs confers increased sensitivity for liquid biopsies and expanded specificity with downstream characterization. Combined, it raises the possibility of a more comprehensive assessment of the disease state for precise diagnosis and monitoring.

Extracellular Vesicles in Allergic Rhinitis and Asthma and Laboratory Possibilities for Their Assessment

Currently, extracellular vesicles (EVs) have been implicated in the etiopathogenesis of many diseases, including lung disorders, with the possibility of diagnostic and therapeutic applications. The analysis of EV in respiratory tract diseases faces many obstacles, including material collection from airways, standardization of isolation techniques, detection methods, the analysis of their content, etc. This review focuses on the role of extracellular vesicles in the pathogenesis of atopic respiratory diseases, especially asthma, with a special focus on their clinical applicability as a diagnostic tool. We also summarize available laboratory techniques that enable the detection of EVs in various biological materials, with particular emphasis on flow cytometry. The opportunities and limitations of detecting EV in bronchoalveolar lavage fluid (BALF) were also described.

Large Extracellular Vesicles-A New Frontier of Liquid Biopsy in Oncology

Extracellular Vesicles (EVs) are emerging as pivotal elements in cancer. Many studies have focused on the role of Small- (S)-EVs but in recent years Large-(L)-EVs have progressively gained increasing interest due to their peculiar content and functions. Tumor-derived L-EVs carry a lot of oncogenic proteins, nucleic acids and lipids to recipient cells and are involved in the reshaping of the tumor microenvironment as well as in the metabolic rewiring and the promotion of the pro-metastatic attitude of cancer cells. Several techniques have been developed for the isolation of L-EVs and commercial kits are also available for efficient and easy recovery of these vesicles. Also, the improvement in DNA sequencing and “omics sciences” profoundly changed the way to analyze and explore the molecular content of L-EVs, thus providing novel and potentially useful cancer biomarkers. Herein, we review the most recent findings concerning the role of L-EVs in cancer and discuss their possible use in oncology as “liquid biopsy” tools as compared to the other classes of EVs.

Cancer-ID: Toward Identification of Cancer by Tumor-Derived Extracellular Vesicles in Blood

Extracellular vesicles (EVs) have great potential as biomarkers since their composition and concentration in biofluids are disease state dependent and their cargo can contain disease-related information. Large tumor-derived EVs (tdEVs, >1 μm) in blood from cancer patients are associated with poor outcome, and changes in their number can be used to monitor therapy effectiveness. Whereas, small tumor-derived EVs (<1 μm) are likely to outnumber their larger counterparts, thereby offering better statistical significance, identification and quantification of small tdEVs are more challenging. In the blood of cancer patients, a subpopulation of EVs originate from tumor cells, but these EVs are outnumbered by non-EV particles and EVs from other origin. In the Dutch NWO Perspectief Cancer-ID program, we developed and evaluated detection and characterization techniques to distinguish EVs from non-EV particles and other EVs. Despite low signal amplitudes, we identified characteristics of these small tdEVs that may enable the enumeration of small tdEVs and extract relevant information. The insights obtained from Cancer-ID can help to explore the full potential of tdEVs in the clinic.

Detection of extracellular vesicles in plasma and urine of prostate cancer patients by flow cytometry and surface plasmon resonance imaging

Large (> 1 μm) tumor-derived extracellular vesicles (tdEVs) enriched from the cell fraction of centrifuged whole blood are prognostic in metastatic castration-resistant prostate cancer (mCRPC) patients. However, the highest concentration of tdEVs is expected in the cell-free plasma fraction. In this pilot study, we determine whether mCRPC patients can be discriminated from healthy controls based on detection of tdEVs (< 1μm, EpCAM+) and/or other EVs, in cell-free plasma and/or urine. The presence of marker+ EVs in plasma and urine samples from mCRPC patients (n = 5) and healthy controls (n = 5) was determined by flow cytometry (FCM) and surface plasmon resonance imaging (SPRi) using an antibody panel and lactadherin. For FCM, the concentrations of marker positive (+) particles and EVs (refractive index <1.42) were determined. Only the lactadherin+ particle and EV concentration in plasma measured by FCM differed significantly between patients and controls (p = 0.017). All other markers did not result in signals exceeding the background on both FCM and SPRi, or did not differ significantly between patients and controls. In conclusion, no difference was found between patients and controls based on the detection of tdEVs. For FCM, the measured sample volumes are too small to detect tdEVs. For SPRi, the concentration of tdEVs is probably too low to be detected. Thus, to detect tdEVs in cell-free plasma and/or urine, EV enrichment and/or concentration is required. Furthermore, we recommend testing other markers and/or a combination of markers to discriminate mCRPC patients from healthy controls.