Screening of Exosome-Derived Proteins and Their Potential as Biomarkers in Diagnostic and Prognostic for Pancreatic Cancer

Exosome biosensors for detection of prostate cancer

Prostate cancer (PCa) is a highly life-threatening disease in men, causing numerous deaths worldwide. As PCa is often diagnosed at a late stage, current diagnostic methods can be invasive and sometimes lead to unnecessary treatments. Therefore, new non-invasive approaches are needed to detect biomarkers for more rapid and accurate PCa diagnosis. Exosomes, extracellular vesicles, provide valuable insights into cellular health and disease progression. Recent studies have indicated the potential use of exosomes as biomarkers for diagnosing PCa. Developing fast, reliable, and sensitive methods for exosome detection is essential. Biosensors, powerful analytical tools for biological samples, have become increasingly crucial in exosome analysis. This review summarizes recent advancements in biosensor technology for exosome detection and provides insights into future perspectives. The goal is to encourage innovative biosensor-based approaches for exosome detection and contribute to the early diagnosis and clinical monitoring of various diseases.

Metabolic Reprogramming Into a Glycolysis Phenotype Induced by Extracellular Vesicles Derived From Prostate Cancer Cells

Most cancer cells adopt a less efficient metabolic process of aerobic glycolysis with high level of glucose uptake followed by lactic acid production, known as the Warburg effect. This phenotypic transition enables cancer cells to achieve increased cellular survival and proliferation in a harsh low-oxygen tumor microenvironment. Also, the resulting acidic microenvironment causes inactivation of the immune system such as T-cell impairment that favors escape by immune surveillance. While lots of studies have revealed that tumor-derived EVs can deliver parental materials to adjacent cells and contribute to oncogenic reprogramming, their functionality in energy metabolism is not well addressed. In this study, we established prostate cancer cells PC-3AcT resistant to cellular death in an acidic culture medium driven by lactic acid. Quantitative proteomics between EVs derived from PC-3 and PC-3AcT cells identified 935 confident EV proteins. According to cellular adaptation to lactic acidosis, we revealed 159 regulated EV proteins related to energy metabolism, cellular shape, and extracellular matrix. These EVs contained a high abundance of glycolytic enzymes. In particular, PC-3AcT EVs were enriched with apolipoproteins including apolipoprotein B-100 (APOB). APOB on PC-3AcT EVs could facilitate their endocytic uptake depending on low density lipoprotein receptor of recipient PC-3 cells, encouraging increases of cellular proliferation and survival in acidic culture media via increased activity and expression of hexokinases and phosphofructokinase. The activation of recipient PC-3 cells can increase glucose consumption and ATP generation, representing an acquired metabolic reprogramming into the Warburg phenotype. Our study first revealed that EVs derived from prostate cancer cells could contribute to energy metabolic reprogramming and that the acquired metabolic phenotypic transition of recipient cells could favor cellular survival in tumor microenvironment.

Serum-derived exosomal miR-7977 combined with miR-451a as a potential biomarker for pancreatic ductal adenocarcinoma

OBJECTIVES

To explore the potential of serum exosomal miRNAs as novel biomarkers for pancreatic ductal adenocarcinoma (PDAC).

METHODS

Serum exosomal miRNAs were screened and verified by microarray analysis and quantitative real-time PCR (qRT-PCR) in patients with PDAC and healthy controls. The correlation between the clinical characteristics of PDAC and candidate exosomal miRNAs was analyzed, and the diagnostic performance of the candidate biomarkers was evaluated.

RESULTS

Serum exosomal miR-7977 and miR-451a were significantly upregulated in PDAC patients compared with healthy controls, and the levels of miR-7977 and miR-451a in serum exosomes were closely associated with the clinical stage and metastasis of PDAC patients. The area under curve (AUC) values of serum exosomal miR-7977 and miR-451a for PDAC were 0.825 and 0.804 in the training set and 0.796 and 0.830 in the validation set, respectively. A biomarker panel consisting of these two miRNAs resulted in a diagnostic power with an AUC of 0.901 in the training set and 0.918 in the validation set.

CONCLUSIONS

Serum exosomal miR-7977 and miR-451a might be diagnostic biomarkers for PDAC. These two miRNAs, when combined, exhibit optimal diagnostic performance.

Proteomic Characterization of Urinary Exosomes with Pancreatic Cancer by Phosphatidylserine Imprinted Polymer Enrichment and Mass Spectrometry Analysis

Exosomes, as carriers of cell-to-cell communication, can serve as promising biomarkers for probing the early diagnosis of cancer. Pancreatic cancer is a common malignant tumor of the pancreas with an insidious onset and difficult early diagnosis. The aim of this study was to capture exosomes in urine samples by phosphatidylserine-molecularly imprinted polymers (PS-MIPs). Transmission electron microscopy and nanoparticle tracking analysis as well as Western blot showed that our molecularly imprinted material can effectively capture urinary exosomes. Three parallel tests verified the reproducibility of the mass spectrometry assay and the stability of the material capture efficiency. Mass Spectrometry with nontargeted proteomics was combined to show differentially expressed proteins in exosomes between 5 pancreatic cancer patients and 5 healthy controls. The most significant changes in the proteomic profile in pancreatic cancer patients compared to healthy controls were the overexpression of SLC9A3R1, SPAG9, and ferritin light chain (FTL) These proteins may have an important role in diagnosis and prognostic assessment, supporting further scientific and clinical studies on pancreatic cancer.

Liquid Biopsy in Pancreatic Ductal Adenocarcinoma: A Review of Methods and Applications

Pancreatic ductal adenocarcinoma (PDAC) remains a malignancy with one of the highest mortality rates. One limitation in the diagnosis and treatment of PDAC is the lack of an early and universal biomarker. Extensive research performed recently to develop new assays which could fit this role is available. In this review, we will discuss the current landscape of liquid biopsy in patients with PDAC. Specifically, we will review the various methods of liquid biopsy, focusing on circulating tumor DNA (ctDNA) and exosomes and future opportunities for improvement using artificial intelligence or machine learning to analyze results from a multi-omic approach. We will also consider applications which have been evaluated, including the utility of liquid biopsy for screening and staging patients at diagnosis as well as before and after surgery. We will also examine the potential for liquid biopsy to monitor patient treatment response in the setting of clinical trial development.

Characterization of effective, simple, and low-cost precipitation methods for depleting abundant plasma proteins to enhance the depth and breadth of plasma proteomics

Plasma is an abundant source of proteins and potential biomarkers to aid in the detection, diagnosis, and prognosis of human diseases. These proteins are often present at low levels in the blood and difficult to identify and measure due to the large dynamic range of proteins. The goal of this work was to characterize and compare various protein precipitation methods related to how they affect the depth and breadth of plasma proteomic studies. Abundant protein precipitation with perchloric acid (PerCA) can increase protein identifications and depth of plasma proteomic studies. Three acid- and four solvent-based precipitation methods were evaluated. All methods tested provided excellent plasma proteomic coverage (>600 identified protein groups) and detected protein in the low pg/mL range. Functional enrichment analysis revealed subtle differences within and larger changes between the precipitant groups. Methanol-based precipitation outperformed the other methods based on identifications and reproducibility. The methods' performance was verified using eight lung cancer patient samples, where >700 protein groups were measured and proteins with an estimated plasma concentration of ∼10 pg/mL were detected. Various protein precipitation agents are amenable to extending the depth and breadth of plasma proteomes. These data can guide investigators to implement inexpensive, high-throughput methods for their plasma proteomic workflows.

Tumor-derived extracellular vesicle proteins as new biomarkers and targets in precision oncology

Extracellular vesicles (EVs) are important carriers of signaling molecules, such as nucleic acids, proteins, and lipids, and have become a focus of increasing interest due to their numerous physiological and pathological functions. For a long time, most studies on EV components focused on noncoding RNAs; however, in recent years, extracellular vesicle proteins (EVPs) have been found to play important roles in diagnosis, treatment, and drug resistance and thus have been considered favorable biomarkers and therapeutic targets for various tumors. In this review, we describe the general protocols of research on EVPs and summarize their multifaceted roles in precision medicine applications, including cancer diagnosis, dynamic monitoring of therapeutic efficacy, drug resistance research, tumor microenvironment interaction research, and anticancer drug delivery.

Protein Arginine Methylation Patterns in Plasma Small Extracellular Vesicles Are Altered in Patients with Early-Stage Pancreatic Ductal Adenocarcinoma

Small extracellular vesicles (sEVs) contain lipids, proteins and nucleic acids, which often resemble their cells of origin. Therefore, plasma sEVs are considered valuable resources for cancer biomarker development. However, previous efforts have been largely focused on the level of proteins and miRNAs in plasma sEVs, and the post-translational modifications of sEV proteins, such as arginine methylation, have not been explored. Protein arginine methylation, a relatively stable post-translational modification, is a newly described molecular feature of PDAC. The present study examined arginine methylation patterns in plasma sEVs derived from patients with early-stage PDAC (n = 23) and matched controls. By utilizing the arginine methylation-specific antibodies for western blotting, we found that protein arginine methylation patterns in plasma sEVs are altered in patients with early-stage PDAC. Specifically, we observed a reduction in the level of symmetric dimethyl arginine (SDMA) in plasma sEV proteins derived from patients with early- and late-stage PDAC. Importantly, immunoprecipitation followed by proteomics analysis identified a number of arginine-methylated proteins exclusively present in plasma sEVs derived from patients with early-stage PDAC. These results indicate that arginine methylation patterns in plasma sEVs are potential indicators of PDAC, a new concept meriting further investigation.