Small Non-Coding RNA Profiling in Plasma Extracellular Vesicles of Bladder Cancer Patients by Next-Generation Sequencing: Expression Levels of miR-126-3p and piR-5936 Increase with Higher Histologic Grades

Abstract

Bladder cancer (BC) is the tenth most frequent cancer worldwide. Due to the need for recurrent cystoscopies and the lack of non-invasive biomarkers, BC is associated with a high management burden. In this respect, small non-coding RNAs (sncRNAs) have been investigated in urine as possible biomarkers for BC, but in plasma their potential has not yet been defined. The expression levels of sncRNAs contained in plasma extracellular vesicles (EVs) from 47 men with BC and 46 healthy controls were assessed by next-generation sequencing. The sncRNA profiles were compared with urinary profiles from the same subjects. miR-4508 resulted downregulated in plasma EVs of muscle-invasive BC patients, compared to controls (adj-p = 0.04). In World Health Organization (WHO) grade 3 (G3) BC, miR-126-3p was upregulated both in plasma EVs and urine, when compared to controls (for both, adj-p < 0.05). Interestingly, two sncRNAs were associated with the risk class: miR-4508 with a downward trend going from controls to high risk BC, and piR-hsa-5936 with an upward trend (adj-p = 0.04 and adj-p = 0.05, respectively). Additionally, BC cases with low expression of miR-185-5p and miR-106a-5p or high expression of miR-10b-5p showed shorter survival (adj-p = 0.0013, adj-p = 0.039 and adj-p = 0.047, respectively). SncRNAs from plasma EVs could be diagnostic biomarkers for BC, especially in advanced grade.

Extracellular Vesicles: New Endogenous Shuttles for miRNAs in Cancer Diagnosis and Therapy?

“…Only miR-126-3p was significantly upregulated in bladder cancers with respect to controls in both plasma EVs and urine. Although in this study authors did not specifically evaluate urinary EVs-miRNAs, but urinary cell-free miRNAs, results suggest caution in translating plasma results to urinary miRNA profiles [104]. Similar results were obtained in type 2 diabetes mellitus by Park et al that first compared various isolation methods and then evaluated the correlations of EVs miRNA between urine and serum samples.…”

Photonic Technologies for Liquid Biopsies: Recent Advances and Open Research Challenges

“…[ 22 ] The loading of molecules into the exosomes is a selective process that is not yet completely clarified. [ 23 ] Exosomes are stable carriers of enriched genetic material and proteins from their cells of origin, thereby holding great promise as biomarker for identifying early stage tumors. This analyte is systematically detectable in the blood, urine, saliva, and other biological fluids of patients with different cancer types.…”

“…Furthermore, some authors have shown that nucleic acids, specially DNA, might not be part of the exosomal cargo, or that other vesicles such as large EVs (oncosomes) bodies hold most of the DNA. [ 14–38 ] As more robust methods appear, these issues will be clarified in a near future. Finally, the potential of exosomes is huge, not only for their use as biomarkers, but also because these EVs can be used as carry‐on particles to deliver therapeutic molecules to specific tissues and sites.…”

“…Among them, the most studied are microRNAs, but recently the attention of researchers has also been directed toward Piwi‐interacting RNAs, circular RNAs, and other small noncoding RNAs. [ 23 ] Another class of RNA species, the long noncoding RNAs, is larger than microRNAs and represents a very versatile and promising group of molecules which, apart from their use as biomarkers, also have a possible therapeutic role.…”

“…[ 46 ] The best‐known snRNA released into body fluids is U2: it has been detected in serum or plasma of lung, colorectal, pancreatic, and ovarian cancers. [ 23 ]…”