Exosomes, new biomarkers in early cancer detection

Serum Membrane Type 1-Matrix Metalloproteinase (MT1-MMP) mRNA Protected by Exosomes as a Potential Biomarker for Gastric Cancer

Background

Our previous research revealed that membrane type 1-matrix metalloproteinase (MT1-MMP) is overexpressed and plays a crucial role in gastric cancer (GC) progression. Exosomes are important for GC carcinogenesis, and the exosomal contents are ideal biomarkers. However, the expression of exosomal MT1-MMP mRNA in serum and its potential significance in GC remains unclear.

Material/Methods

The expression of exosomal MT1-MMP mRNA in serum of patients with GC, chronic gastritis, or atypical hyperplasia, and healthy controls was detected using real-time quantitative RT-PCR. Serum CEA, CA19-9, and CA72-4 were also measured by electrochemiluminescence assay.

Results

Exosomes were isolated and identified in serum, and serum exosomal MT1-MMP mRNA was found to be higher in patients with GC compared with healthy controls and patients with chronic gastritis or atypical hyperplasia (all P<0.05). Serum exosomal MT1-MMP mRNA was significantly correlated with tumor diameter, differentiation, Borrmann type, invasion depth, lymphatic metastasis, distal metastasis, and TNM stage. The AUC of exosomal MT1-MMP mRNA was 0.788 (95% CI: 0.714–0.850) with 63.9% sensitivity and 87.1% specificity, and was higher than that of CEA (0.655 (95% CI: 0.573–0.730)). The combination of 2 markers gave an AUC of 0.821 (95% CI: 0.750–0.878), which was better than with the individual marker. The sensitivity, specificity, and positive and negative predictive values were 75.6%, 83.9%, 94.7%, and 47.3%, respectively. Moreover, the multiple logistic regression model showed that tumor diameter, differentiation, invasion depth, and exosomal MT1-MMP mRNA were the risk factors for lymphatic metastasis in GC.

Conclusions

Our results characterized serum exosomal MT1-MMP mRNA in GC, providing a foundation for discovering serum exosomes-targeted biomarkers for GC diagnosis.

An integrated microfluidic system for on-chip enrichment and quantification of circulating extracellular vesicles from whole blood

Circulating extracellular vesicles (EVs), which can contain a wide variety of molecules such as proteins, messenger ribonucleic acids (mRNAs), micro ribonucleic acids (miRNAs) and deoxyribonucleic acids (DNAs) from cells or tissues of origin, have attracted great interest given their potential to serve as biomarkers that can be harvested in body fluids (i.e., relatively non-invasive). Since enrichment and detection of circulating EVs from whole blood have proven challenging, we report herein a fully integrated microfluidic system combining a membrane-based filtration module (i.e. pneumatically-driven microfluidic devices) and a magnetic-bead based immunoassay capable of automating blood treatment, EV enrichment, and EV quantification directly from human whole blood. Three functional modules were implemented; the first, a stirring-enhanced filtration module for separating plasma from blood cells, was characterized by a plasma recovery rate of 65%, a filtrate flow rate of 22 μL min^-1, and a vesicle recovery rate of 94% within only 8 min (using 500 μL of blood). The second module, a magnetic bead-based EV enrichment device for immunocapture of circulating EVs from plasma, was characterized by a capture rate of 45%. The final module performed an on-chip enzyme-linked immunosorbent assay for plasma EV quantification in plasma. Given the automated capacity of this system, it could show promise in circulating EV research and clinical point-of-care applications.

Identification of serum exosomal microRNAs in acute spinal cord injured rats

It is important to find specific and easily detectable diagnostic markers in acute stage of spinal cord injury for guiding treatment and estimating prognosis. Although, microRNAs are attractive biomarkers, there is still no uniform standard for clinical evaluation of spinal cord injury based on “free circulation” miRNA spectrum. The reason may be that miRNA analysis from biological fluids is influenced by many pre-analysis variables. Exosome miRNAs are widely distributed in body fluids and have many advantages comparing with free miRNAs. The specific miRNAs in the central nervous system can be transported to the peripheral circulation and concentrated in exosomes. Therefore, we hypothesized that there might be some physiological changes associated with spinal cord injury in serum exosomal miRNAs. Using next-generation sequencing, miRNA profiles in serum exosomes of sham and acute spinal cord injury rats were analyzed, and integrative bioinformatics were used to analyze the function and regulation of putative target genes. The results showed that acute spinal cord injury can lead to changes in miRNA expression in the circulating exosomes. The changed miRNAs and their associated pathways may explain the pathology of acute spinal cord injury. More importantly, we determined serum exosomal miR-125b-5p, miR-152-3p, and miR-130a-3p are specific and easily detectable diagnostic markers in acute spinal cord injury. More interestingly, we also found some valuable known and novel miRNAs. Further bioinformatics analysis and functional research will be of great help to make clear their role in the pathological process of spinal cord injury and judging whether they can be used as diagnostic markers.

Impact statement

This research hypothesized that there might be some physiological changes associated with SCI in serum exosomal miRNAs. Using next-generation sequencing, miRNA profiles in serum exosomes of sham and acute SCI rats were analyzed, and integrative bioinformatics were used to analyze the function and regulation of putative target genes. The results showed that acute SCI can lead to changes in miRNA expression in the circulating exosomes. The changed miRNAs and their associated pathways may explain the pathology of acute SCI. More importantly, we determined serum exosomal miR-125b-5p, miR-152-3p, and miR-130a-3p are specific and easily detectable diagnostic markers in acute SCI.