Cell-free microRNAs as cancer biomarkers: the odyssey of miRNAs through body fluids. Med Oncol. 2014;31:295. [PMID: 25362261 DOI: 10.1007/s12032-014-0295-y]

Circulating microRNAs as Potential Biomarkers of Overweight and Obesity in Adults: A Narrative Review

In an obesogenic environment, such as the one we have been experiencing in recent decades, epigenetics provides answers to the relationship between hereditary and environmentally acquired patterns that have significantly contributed to the global rise in obesity prevalence. MicroRNA (miRNA) constitutes a diminutive non-coding small RNA molecule, 20 to 24 nucleotides in length, that functions as a regulator of gene regulation at the post-translational level. Circulating miRNAs (c-miRNAs) have been detected in multiple body fluids, including blood, plasma, serum, saliva, milk from breastfeeding mothers, and urine. These molecules hold significant therapeutic value and serve as extracellular biomarkers in metabolic diseases. They aid in the diagnosis and tracking of therapy responses, as well as dietary and physical habit modifications. Researchers have studied c-miRNAs as potential biomarkers for diagnosing and characterizing systemic diseases in people of all ages and backgrounds since then. These conditions encompass dyslipidemia, type 2 diabetes mellitus (T2DM), cardiovascular risk, metabolic syndrome, cardiovascular diseases, and obesity. This review therefore analyzes the usefulness of c-miRNAs as therapeutic markers over the past decades. It also provides an update on c-miRNAs associated with general obesity and overweight, as well as with the most prevalent pathologies in the adult population. It also examines the effect of different nutritional approaches and physical activity regarding the activity of miRNAs in circulation in adults with overweight or general obesity. All of this is done with the aim of evaluating their potential use as biomarkers in various research contexts related to overweight and obesity in adults.

Advances in Prostate Cancer Biomarkers and Probes

Prostate cancer is one of the most prevalent malignant tumors in men worldwide, and early diagnosis is essential to improve patient survival. This review provides a comprehensive discussion of recent advances in prostate cancer biomarkers, including molecular, cellular, and exosomal biomarkers. The potential of various biomarkers such as gene fusions (TMPRSS2-ERG), noncoding RNAs (SNHG12), proteins (PSA, PSMA, AR), and circulating tumor cells (CTCs) in the diagnosis, prognosis, and targeted therapies of prostate cancer is emphasized. In addition, this review systematically explores how multi-omics data and artificial intelligence technologies can be used for biomarker discovery and personalized medicine applications. In addition, this review provides insights into the development of specific probes, including fluorescent, electrochemical, and radionuclide probes, for sensitive and accurate detection of prostate cancer biomarkers. In conclusion, this review provides a comprehensive overview of the status and future directions of prostate cancer biomarker research, emphasizing the potential for precision diagnosis and targeted therapy.

The emerging role of liquid biopsy in oral squamous cell carcinoma detection: advantages and challenges

INTRODUCTION

Oral Squamous Cell Carcinoma (OSCC), the sixth most widespread malignancy in the world, accounts for 90% of all cases of oral cancer. The primary risk factors are tobacco chewing, alcohol consumption, viral infection, and genetic modifications. OSCC has a high morbidity rate due to the lack of early diagnostic methods. Nowadays, liquid biopsy plays a vital role in the initial diagnosis of oral cancer. ctNAs extracted from saliva and serum/plasma offer meaningful insights into tumor genetics and dynamics. The interplay of these elements in saliva and serum/plasma showcases their significance in advancing noninvasive, effective OSCC detection and monitoring.

AREAS COVERED

This review mainly focused on the role of liquid biopsy as an emerging point in the diagnosis and prognosis of OSCC and the current advancements and challenges associated with liquid biopsy.

EXPERT OPINION

Liquid biopsy is regarded as a new, minimally invasive, real-time monitoring tool for cancer diagnosis and prognosis. Many biomolecules found in bodily fluids, including ctDNA, ctRNA, CTCs, and EVs, are significant biomarkers to identify cancer in its early stages. Despite these groundbreaking strides, challenges persist. Standardization of sample collection, isolation, processing, and detection methods is imperative for ensuring result reproducibility across diverse studies.

Evidence-based procedures to improve the reliability of circulating miRNA biomarker assays

Circulating cell-free microRNAs (cfmiRNA) are an emerging class of biomarkers that have shown great promise in the clinical diagnosis, treatment, and monitoring of several pathological conditions, including cancer. However, validation and clinical implementation of cfmiRNA biomarkers has been hindered by the variability introduced during different or suboptimal specimen collection and handling practices. To address the need for standardization and evidence-based guidance, the National Cancer Institute (NCI) developed a new Biospecimen Evidenced-Based Practices (BEBP) document, entitled "Cell-free miRNA (cfmiRNA): Blood Collection and Processing". The BEBP, the fourth in the document series, contains step-by-step procedural guidelines on blood collection, processing, storage, extraction, and quality assessment that are tailored specifically for cfmiRNA analysis of plasma and serum. The workflow outlined in the BEBP is based on the available literature and recommendations of an expert panel. The BEBP contains the level of detail required for development of evidence-based standard operating procedures (SOPs) as well as the flexibility needed to accomodate (i) discovery- and inquiry-based studies and (ii) the different constraints faced by research labs, industry, clinical and academic institutions to foster widespread implementation. Guidance from the expert panel also included recommendations on study design, validating changes in workflow, and suggested quality thresholds to delineate meaningful changes in cfmiRNA levels. The NCI cfmiRNA: Blood Collection and Processing BEBP is available here as supplementary information as well as through the NCI Biorepositories and Biospecimen Research Branch (BBRB) (https://biospecimens.cancer.gov/resources/bebp.asp).

Method for the extraction of circulating nucleic acids based on MOF reveals cell-free RNA signatures in liver cancer

Cell-free RNA (cfRNA) allows assessment of health, status, and phenotype of a variety of human organs and is a potential biomarker to non-invasively diagnose numerous diseases. Nevertheless, there is a lack of highly efficient and bias-free cfRNA isolation technologies due to the low abundance and instability of cfRNA. Here, we developed a reproducible and high-efficiency isolation technology for different types of cell-free nucleic acids (containing cfRNA and viral RNA) in serum/plasma based on the inclusion of nucleic acids by metal-organic framework (MOF) materials, which greatly improved the isolation efficiency and was able to preserve RNA integrity compared with the most widely used research kit method. Importantly, the quality of cfRNA extracted by the MOF method is about 10-fold that of the kit method, and the MOF method isolates more than three times as many different RNA types as the kit method. The whole transcriptome mapping characteristics of cfRNA in serum from patients with liver cancer was described and a cfRNA signature with six cfRNAs was identified to diagnose liver cancer with high diagnostic efficiency (area under curve = 0.905 in the independent validation cohort) using this MOF method. Thus, this new MOF isolation technique will advance the field of liquid biopsy, with the potential to diagnose liver cancer.

Isolation and Detection of Exosomal Mir210 Using Carbon Nanomaterial-Coated Magnetic Beads

MicroRNAs (miRNAs) are short non-coding RNAs that are found in various cellular compartments and play an important role in regulating gene expression. Extracellular miRNAs, such as those found within extracellular vesicles such as exosomes are involved in cell-to-cell communication. The intercellular transfer of miRNAs has been implicated in various diseases' pathogenesis including cancer and has been studied extensively as potential cancer biomarkers. However, the extraction of miRNA from exosomes is still a challenging task. The current nucleic acid extraction assays are expensive and labor-intensive. In this study, we demonstrated a microfluidic device for aptamer-based magnetic separation of the exosomes and subsequent detection of the miRNA using a fluorescence switching assay, which was enabled by carbon nanomaterials coated on magnetic beads. In the OFF state, the fluorophore-labelled cDNA is quenched using carbon nanomaterials. However, when the target miRNA210 is introduced, the cDNA detaches from the bead's surface, which leads to an increase in the fluorescence intensity (ON state). This increment was found to be proportional to miRNA concentration within the dynamic range of 0-100 nM with a detection limit of 5 pM. The assay was validated with spiked miRNA using the standard RT-PCR method. No notable cross-reactivity with other closely related miRNAs was observed. The developed method can be utilized for the minimally invasive detection of cancer biomarkers.

Circulating miRNAs as a Tool for Early Diagnosis of Endometrial Cancer-Implications for the Fertility-Sparing Process: Clinical, Biological, and Legal Aspects

This review article explores the possibility of developing an integrated approach to the management of the different needs of endometrial cancer (EC) patients seeking to become pregnant. Life preservation of the woman, health preservation of the baby, a precocious and-as much as possible-minimally invasive characterization of the health and fertility parameters of the patient, together with the concerns regarding the obstetric, neonatal, and adult health risks of the children conceived via assisted reproductive techniques (ART) are all essential aspects of the problem to be taken into consideration, yet the possibility to harmonize such needs through a concerted and integrated approach is still very challenging. This review aims to illustrate the main features of EC and how it affects the normal physiology of pre-menopausal women. We also focus on the prospect of a miR-based, molecular evaluation of patient health status, including both EC early diagnosis and staging and, similarly, the receptivity of the woman, discussing the possible evaluation of both aspects using a single specific panel of circulating miRs in the patient, thus allowing a relatively fast, non-invasive testing with a significantly reduced margin of error. Finally, the ethical and legal/regulatory aspects of such innovative techniques require not only a risk-benefit analysis; respect for patient autonomy and equitable health care access allocation are fundamental issues as well.

Expression Profile of miRNA from High, Middle, and Low Stress-Responding Sheep during Bacterial Endotoxin Challenge

Animals respond to stress by activating a wide array of physiological and behavioral responses that are collectively referred to as the stress response. MicroRNAs (miRNAs) are small, noncoding RNAs that play key roles in the regulation of homeostasis. There are many reports demonstrating examples of stress-induced miRNA expression profiles. The aim of this study was to determine the circulatory miRNA profile of variable stress-responding lambs (n = 112) categorized based on their cortisol levels as high (HSR, 336.2 ± 27.9 nmol/L), middle (MSR, 147.3 ±9.5 nmol/L), and low (LSR, 32.1 ± 10.4 nmol/L) stress responders post-LPS challenge (400 ng/kg iv). Blood was collected from the jugular vein at 0 (T0) and 4 h (T4) post-LPS challenge, and miRNAs were isolated from four animals from each group. An array of 84 miRNAs and 6 individual miRNAs were evaluated using qPCR. Among 90 miRNAs, there were 48 differentially expressed (DE) miRNAs (log fold change (FC) > 2 < log FC) in the HSR group, 46 in the MSR group, and 49 in the LSR group compared with T0 (control) samples. In the HSR group, three miRNAs, miR-485-5p, miR-1193-5p, and miR-3957-5p were significantly (p < 0.05) upregulated, while seven miRNAs, miR-376b-3p, miR-376c-3p, miR-411b-5p, miR-376a-3p, miR-376b-3p, miR-376c-3p, and miR-381-3p, were downregulated (p < 0.05) as compared to the LSR and MSR groups. Functional analysis of DE miRNAs revealed their roles in Ras and MAPK signaling, cytokine signaling, the adaptive immune system, and transcription pathways in the HSR phenotype, implicating a hyper-induced acute-phase response. In contrast, in the LSR group, enriched pathways included glucagon signaling metabolic regulation, the transportation of amino acids and ions, and the integration of energy metabolism. Taken together, these results indicate variation in the acute-phase response to an immune stress challenge, and these miRNAs are implicated in regulating responses within cortisol-based phenotypes.

Liquid Biopsy in Diagnosis and Prognosis of Non-Metastatic Prostate Cancer

Currently, sensitive and specific methods for the detection and prognosis of early stage PCa are lacking. To establish the diagnosis and further identify an appropriate treatment strategy, prostate specific antigen (PSA) blood test followed by tissue biopsy have to be performed. The combination of tests is justified by the lack of a highly sensitive, specific, and safe single test. Tissue biopsy is specific but invasive and may have severe side effects, and therefore is inappropriate for screening of the disease. At the same time, the PSA blood test, which is conventionally used for PCa screening, has low specificity and may be elevated in the case of noncancerous prostate tumors and inflammatory conditions, including benign prostatic hyperplasia and prostatitis. Thus, diverse techniques of liquid biopsy have been investigated to supplement or replace the existing tests of prostate cancer early diagnosis and prognostics. Here, we provide a review on the advances in diagnosis and prognostics of non-metastatic prostate cancer by means of various biomarkers extracted via liquid biopsy, including circulating tumor cells, exosomal miRNAs, and circulating DNAs.

Circulating serum miR-1246 and miR-1229 as diagnostic biomarkers in colorectal carcinoma

Background

Colorectal cancer (CRC) is one of the most common cancers worldwide. Although colonoscopy is considered as the "Gold Standard" technique to detect CRC, its application is invasive and cost incurred. Thus, noninvasive or minimally invasive approaches are of utmost importance. The aberrant expression of some microRNAs (miRNAs, miRs) has been suggested in association with CRC pathogenesis. This study aimed to validate if circulating serum miR-1229 and miR-1246 are diagnostic biomarkers for CRC.

Materials and Methods

Serum samples were isolated from 45 CRC patients and also 45 healthy controls (HC). The expression levels of circulating serum-derived miR-1229 and miR-1246 were evaluated by quantitative real-time polymerase chain reaction. Receiver operating characteristic (ROC) curves were constructed to evaluate the CRC diagnostic accuracy of selected miRNAs. Furthermore, the association of candidate miRNAs and clinicopathological characteristics were evaluated. Functional enrichment of the candidate miRNAs was applied using in silico tools.

Results

The expression of miR-1229 and miR-1246 was significantly higher in CRC patients than HC (P < 0.0001) and also was found in association with lymph node metastasis (P < 0.05). We demonstrated a significant up-regulation of serum-derived miR-1246 in advanced tumor-node-metastasis stage III of CRC patients (P < 0.05). Areas under the ROC curve of miR-1229 and miR-1246 were 0.81 and 0.84, respectively (P < 0.0001).

Conclusion

We confirmed the capability of circulating serum miR-1229 and miR-1246 as novel diagnostic biomarkers for CRC.

miRNAs as molecular biomarkers for prostate cancer

MicroRNAs (miRNAs) are short noncoding RNA able to regulate specific mRNA stability, thus influencing target gene expression. Disrupted levels of several miRNA have been associated with prostate cancer, the leading cause of cancer death among men and the fifth leading cause of death worldwide. Here, we investigated whether miR-145, miR-148, and miR-185 circulating levels in plasma could be used as molecular biomarkers, to allow distinguishing between individuals with benign prostatic hyperplasia, precancerous lesion, and prostate cancer. In this study, we recruited 170 urological clinic patients with suspected prostate cancer who underwent prostate biopsy. Total RNA was isolated from plasma, and TaqMan MicroRNA assays were used to analyze miR-145, miR-185, and miR-148 expression. First, differential miRNA expression among patient groups was evaluated. Then, miRNA levels were combined with clinical assessment outcomes, including results from invasive tests, using multivariate analysis to examine their ability in discriminating among the three patient groups. Our results suggest that miRNA is a promising molecular tool for clinical management of at-risk patients.

Identification and profiling of stable microRNAs in hemolymph of young and old Locusta migratoria fifth instars

Since the discovery of the first microRNA (miRNA) in the nematode Caenorhabditis elegans, numerous novel miRNAs have been identified which can regulate presumably every biological process in a wide range of metazoan species. In accordance, several insect miRNAs have been identified and functionally characterized. While regulatory RNA pathways are traditionally described at an intracellular level, studies reporting on the presence and potential role of extracellular (small) sRNAs have been emerging in the last decade, mainly in mammalian systems. Interestingly, evidence in several species indicates the functional transfer of extracellular RNAs between donor and recipient cells, illustrating RNA-based intercellular communication. In insects, however, reports on extracellular small RNAs are emerging but the number of detailed studies is still very limited. Here, we demonstrate the presence of stable sRNAs in the hemolymph of the migratory locust, Locusta migratoria. Moreover, the levels of several extracellular miRNAs (ex-miRNAs) present in locust hemolymph differed significantly between young and old fifth nymphal instars. In addition, we performed a 'proof of principle' experiment which suggested that extracellularly delivered miRNA molecules are capable of affecting the locusts' development.

Exploring the pathogenesis of type 2 diabetes mellitus intestinal damp-heat syndrome and the therapeutic effect of Gegen Qinlian Decoction from the perspective of exosomal miRNA

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes is a common, complex, chronic metabolic disease. A randomized, double-blind, placebo-parallel controlled clinical study has shown that Gegen Qinlian Decoction (GQD) can reduce glycosylated hemoglobin in type 2 diabetes mellitus (T2DM) intestinal damp-heat syndrome patients in a dose-dependent manner.

AIM

To explore the pathogenesis of T2DM intestinal damp-heat syndrome and the therapeutic effect of GQD from the perspective of exosomal microRNA (miRNA).

METHODS

Eligible patients were selected and treated with GQD for 3 months to evaluate their clinical efficacy. Effective cases were matched with healthy volunteers, and saliva samples were collected. Exosomal miRNA was extracted from saliva and analyzed by chip sequencing. Subsequently, the function of the differential gene and the signal transduction pathway were analyzed using bioinformatics technology. Finally, three target miRNAs were randomly selected from the T2DM group/healthy group, and two target miRNAs in the T2DM before treatment/after treatment group were randomly selected for qPCR verification. Finally, we conducted a correlation analysis of the miRNAs and clinical indicators. The registration number for this research is ChiCTR-IOR-15006626.

RESULTS

(1) The expression of exosomal miRNA chips showed that there were 14 differentially expressed miRNAs in the T2DM group/healthy group, and 26 differentially expressed miRNAs in the T2DM before treatment/after treatment group. (2) Enrichment results showed that in the T2DM group/healthy group, it was primarily related to cell development, body metabolism, TGF-β, and ErbB signaling pathways. In the T2DM before treatment/after treatment group, it was mainly related to cellular metabolic regulation processes, and insulin, Wnt, and AMPK signaling pathways. (3) The qPCR verification showed that the expressions of hsa-miR-9-5p, hsa-miR-150-5p, and hsa-miR-216b-5p in the T2DM group was higher (P<0.05). Following GQD treatment, hsa-miR-342-3p and hsa-miR-221-3p were significantly downregulated (P<0.05). (4) hsa-miR-9-5p was positively correlated with BMI (P<0.05), and hsa-miR-150-5p was positively correlated with total cholesterol and triglycerides (P<0.05). The GQD efficacy-related gene hsa-miR-342-3p was positively correlated with the patient's initial blood glucose level (P<0.05), and hsa-miR-221-3p was positively correlated with total cholesterol and triglycerides (P<0.05).

CONCLUSION

The exosomal miRNA expression profile and signaling pathways related to T2DM intestinal damp-heat syndrome and the efficacy of GQD were established, which provides an alternative strategy for precision traditional Chinese medicine treatment.

Targeting the metabolism of cancer stem cells by energy disruptor molecules

Cancer stem cells (CSCs) have been identified in various tumor types. CSCs are believed to contribute to tumor metastasis and resistance to conventional therapy. So targeting these cells could be an effective strategy to eliminate tumors and a promising new type of cancer treatment. Alterations in metabolism play an essential role in CSC biology and their resistance to treatment. The metabolic properties pathways in CSCs are different from normal cells, and to some extent, are different from regular tumor cells. Interestingly, CSCs can use other nutrients for their metabolism and growth. The different metabolism causes increased sensitivity of CSCs to agents that disrupt cellular homeostasis. Compounds that interfere with the central metabolic pathways are known as energy disruptors and can reduce CSC survival. This review highlights the differences between regular cancer cells and CSC metabolism and discusses the action mechanisms of energy disruptors at the cellular and molecular levels.

Development of neoantigens: from identification in cancer cells to application in cancer vaccines

Introduction: The discovery of neoantigens as mutated proteins specifically expressed in tumor cells but not in normal cells has led to improved cancer vaccines. Targeting neoantigens can induce anti-tumor T-cell responses to destroy tumors without damaging healthy cells. Extensive advances in genome sequencing technology and bioinformatics analysis have made it possible to discover and design effective neoantigens for use in therapeutic cancer vaccines. Neoantigens-based therapeutic personalized vaccines have shown promising results in cancer immunotherapy.Areas covered: We discuss the types of cancer neoantigens that can be recognized by the immune system in this review. We also summarize the detection, identification, and design of neoantigens and their appliction in developing cancer vaccines. Finally, clinical trials of neoantigen-based vaccines, their advantages, and their limitations are reviewed. From 2015 to 2020, the authors conducted a literature search of controlled randomized trials and laboratory investigations that that focused on neoantigens, their use in the design of various types of cancer vaccines.Expert opinion: Neoantigens are cancer cell-specific antigens, which their expression leads to the immune stimulation against tumor cells. The identification and delivery of specific neoantigens to antigen-presenting cells (APCs) with the help of anti-cancer vaccines promise novel and more effective cancer treatments.

Liquid biopsy in cholangiocarcinoma: Current status and future perspectives

Cholangiocarcinoma (CCA) are a heterogeneous group of tumors in terms of aetiology, natural history, morphological subtypes, molecular alterations and management, but all sharing complex diagnosis, management, and poor prognosis. Several mutated genes and epigenetic changes have been detected in CCA, with the potential to identify diagnostic and prognostic biomarkers and therapeutic targets. Accessing tumoral components and genetic material is therefore crucial for the diagnosis, management and selection of targeted therapies; but sampling tumor tissue, when possible, is often risky and difficult to be repeated at different time points. Liquid biopsy (LB) represents a way to overcome these issues and comprises a diverse group of methodologies centering around detection of tumor biomarkers from fluid samples. Compared to the traditional tissue sampling methods LB is less invasive and can be serially repeated, allowing a real-time monitoring of the tumor genetic profile or the response to therapy. In this review, we analysis the current evidence on the possible roles of LB (circulating DNA, circulating RNA, exosomes, cytokines) in the diagnosis and management of patients affected by CCA.

Non-coding RNAs underlying chemoresistance in gastric cancer

BACKGROUND

Gastric cancer (GC) is a major health issue in the Western world. Current clinical imperatives for this disease include the identification of more effective biomarkers to detect GC at early stages and enhance the prevention and treatment of metastatic and chemoresistant GC. The advent of non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long-non coding RNAs (lncRNAs), has led to a better understanding of the mechanisms by which GC cells acquire features of therapy resistance. ncRNAs play critical roles in normal physiology, but their dysregulation has been detected in a variety of cancers, including GC. A subset of ncRNAs is GC-specific, implying their potential application as biomarkers and/or therapeutic targets. Hence, evaluating the specific functions of ncRNAs will help to expand novel treatment options for GC.

CONCLUSIONS

In this review, we summarize some of the well-known ncRNAs that play a role in the development and progression of GC. We also review the application of such ncRNAs in clinical diagnostics and trials as potential biomarkers. Obviously, a deeper understanding of the biology and function of ncRNAs underlying chemoresistance can broaden horizons toward the development of personalized therapy against GC.

Magnetic nanoparticle-based amplification of microRNA detection in body fluids for early disease diagnosis

Circulating biomarkers such as microRNAs (miRNAs), short noncoding RNA strands, represent prognostic and diagnostic indicators for a variety of physiological disorders making their detection and quantification an attractive approach for minimally invasive early disease diagnosis. However, highly sensitive and selective detection methods are required given the generally low abundance of miRNAs in body fluids together with the presence of large amounts of other potentially interfering biomolecules. Although a variety of miRNA isolation and detection methods have been established in clinics, they usually require trained personnel and often constitute labor-, time- and cost-intensive approaches. During the last years, nanoparticle-based biosensors have received increasing attention due to their superior detection efficiency even in very low concentration regimes. This is based on their unique physicochemical properties in combination with their high surface area that allows for the immobilization of multiple recognition sites resulting in fast and effective recognition of analytes. Among various materials, magnetic nanoparticles have been identified as useful tools for the separation, concentration, and detection of miRNAs. Here, we review state-of-the-art technology with regard to magnetic particle-based miRNA detection from body fluids, critically discussing challenges and future perspective of such biosensors while comparing their handling, sensitivity as well as selectivity against the established miRNA isolation and detection methods.

miR-224 is an early-stage biomarker of hepatocellular carcinoma with miR-224 and miR-125b as prognostic biomarkers

Aim: The aim was to systematically investigate the miRNA biomarkers for early diagnosis of hepatocellular carcinoma (HCC). Materials & methods: A systematic review and meta-analysis of miRNA expression in HCC were performed. Results: A total of 4903 cases from 30 original studies were comprehensively analyzed. The sensitivity and specificity of miR-224 in discriminating early-stage HCC patients from benign lesion patients were 0.868 and 0.792, which were superior to α-fetoprotein. Combined miR-224 with α-fetoprotein, the sensitivity and specificity were increased to 0.882 and 0.808. Prognostic survival analysis showed low expression of miR-125b and high expression of miR-224 were associated with poor prognosis. Conclusion: miR-224 had a prominent diagnostic efficiency in early-stage HCC, with miR-224 and miR-125b being valuable in the prognostic diagnosis.

Circulating Non-coding RNAs in Renal Cell Carcinoma-Pathogenesis and Potential Implications as Clinical Biomarkers

Liquid biopsy-the determination of circulating cells, proteins, DNA or RNA from biofluids through a "less invasive" approach-has emerged as a novel approach in all cancer entities. Circulating non-(protein) coding RNAs including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and YRNAs can be passively released by tissue or cell damage or actively secreted as cell-free circulating RNAs, bound to lipoproteins or carried by exosomes. In renal cell carcinoma (RCC), a growing body of evidence suggests circulating non-coding RNAs (ncRNAs) such as miRNAs, lncRNAs, and YRNAs as promising and easily accessible blood-based biomarkers for the early diagnosis of RCC as well as for the prediction of prognosis and treatment response. In addition, circulating ncRNAs could also play a role in RCC pathogenesis and progression. This review gives an overview over the current study landscape of circulating ncRNAs and their involvement in RCC pathogenesis as well as their potential utility as future biomarkers in RCC diagnosis and treatment.

Advances of exosome isolation techniques in lung cancer

Lung cancer (LC) is among the leading causes of death all over the world and it is often diagnosed at advanced or metastatic stages. Exosomes, derived from circulating vesicles that are released from the multivesicular body, can be utilized for diagnosis and also the prognosis of LC at early stages. Exosomal proteins, RNAs, and DNAs can help to better discern the prognostic and diagnostic features of LC. To our knowledge, there are various reviews on LC and the contribution of exosomes, but none of them are about the exome techniques and also their efficiency in LC. To fill this gap, in this review, we summarize the recent investigations regarding isolation and also the characterization of exosomes of LC cells. Furthermore, we discuss the noncoding RNAs as biomarkers and their applications in the diagnosis and prognosis of LC. Finally, we compare the efficacy of exosome isolation methods to better fi + 6 + guring out feasible techniques.

A panel of six-circulating miRNA signature in serum and its potential diagnostic value in colorectal cancer

AIM

Colorectal carcinoma (CRC) is one of the most prevalent cancers throughout the world. Circulating serum-derived microRNAs (miRNAs, miRs) can be used as non-invasive biomarkers for CRC diagnosis. This study aimed to identify a panel of six serum exosomal miRNAs as novel diagnostic biomarkers for CRC.

MAIN METHODS

Exosomes were isolated and characterized from the conditioned media of the human colon adenocarcinoma cells (HCT-116 and Caco2). Sera were isolated from peripheral blood of 45 CRC and also 45 healthy individuals. The expression levels and diagnostic value of candidate circulating miRNAs (miR-19a, miR-20a, miR-150, miR-143, miR-145, and let-7a) were measured through quantitative real-time PCR. Receiver operating characteristic (ROC) curves were applied to evaluate the diagnostic accuracy of selected miRNAs. The association of candidate miRNAs and clinicopathological characteristics e.g. tumor node metastasis (TNM) staging and lymph node metastasis (LNM) were further evaluated.

KEY FINDINGS

Circulating serum miR-19a, miR-20a, miR-150, and let-7a were significantly up-regulated in CRC patients, while miR-143 and miR-145 showed a significant down-regulation. The higher levels of miR-143 and miR-145 in patients with TNM stage I-II were detected, whereas miR-19a, miR-20a, miR-150, and let-7a were highly expressed in TNM stage III. The expression levels of miR-19a, miR-20a, and miR-150 were positively correlated with LNM status, while the expression levels of miR-143 and miR-145 were lower in patients with LNM. Area under the ROC curves of miR-19a, miR-20a, miR-150, miR-143, miR-145, and let-7a were 0.87, 0.83, 0.75, 0.76, 0.78 and 0.71, respectively.

SIGNIFICANCE

We established a panel of six-circulating miRNA signature (i.e. miR-19a, miR-20a, miR-143, miR-145, miR-150, and let-7a) in serum as a non-invasive biomarker for CRC diagnosis. These findings confirm that serum-derived miRNAs have a strong potential to be a diagnostic biomarker for patients with CRC.

Small regulatory noncoding RNAs in Drosophila melanogaster: biogenesis and biological functions

RNA interference (RNAi) is an important phenomenon that has diverse genetic regulatory functions at the pre- and posttranscriptional levels. The major trigger for the RNAi pathway is double-stranded RNA (dsRNA). dsRNA is processed to generate various types of major small noncoding RNAs (ncRNAs) that include microRNAs (miRNAs), small interfering RNAs (siRNAs) and PIWI-interacting RNAs (piRNAs) in Drosophila melanogaster (D. melanogaster). Functionally, these small ncRNAs play critical roles in virtually all biological systems and developmental pathways. Identification and processing of dsRNAs and activation of RNAi machinery are the three major academic interests that surround RNAi research. Mechanistically, some of the important biological functions of RNAi are achieved through: (i) supporting genomic stability via degradation of foreign viral genomes; (ii) suppressing the movement of transposable elements and, most importantly, (iii) post-transcriptional regulation of gene expression by miRNAs that contribute to regulation of epigenetic modifications such as heterochromatin formation and genome imprinting. Here, we review various routes of small ncRNA biogenesis, as well as different RNAi-mediated pathways in D. melanogaster with a particular focus on signaling pathways. In addition, a critical discussion of the most relevant and latest findings that concern the significant contribution of small ncRNAs to the regulation of D. melanogaster physiology and pathophysiology is presented.

Aberrant expression of a five-microRNA signature in breast carcinoma as a promising biomarker for diagnosis

BACKGROUND

Breast cancer (BC) is the most common malignancy among females with dismal quality of life in patients. It has been proven that epigenetic factors, especially microRNAs, are involved in breast carcinogenesis and progression. This study aimed to assess the expression and clinical performances of a five-microRNA signature (miR-127-3p, miR-133a-3p, miR-155-5p, miR-199b-5p, and miR-342-5p) in breast cancer and adjacent normal tissues to identify a potential biomarker for BC and investigate the relationship between their expression and clinicopathological features of BC patients as well.

METHODS

In this case-control investigation, we recruited 50 pairs of tumor and matched non-tumor surgical specimens from patients diagnosed with BC. Expression levels of miR-127-3p, miR-133a-3p, miR-155-5p, miR-199b-5p, and miR-342-5p were measured in BC and adjacent normal tissues by RT-qPCR.

RESULTS

We found that miR-127-3p, miR-133a-3p, miR-199b-5p, and miR-342-5p were significantly down-regulated, while miR-155-5p was significantly up-regulated in BC tumor tissues compared with the corresponding adjacent normal tissues. The decreased expression of miR-127-3p, miR-133a-3p, miR-342-5p, and up-regulation of miR-155-5p showed a significant correlation with disease stage. We also found a significant down-regulation of miR-127-3p, miR-199b-5p, and miR-342-5p compared in HER-2-negative patients. Our results indicated that miR-155-5p had a higher expression level in HER-2-positive patients. Receiver operating characteristic (ROC) curve analysis demonstrated that all these five microRNAs can serve as potential biomarkers to distinguish between tumor and non-tumor breast tissue samples.

CONCLUSIONS

The present findings suggested that dysregulation of this five-miRNA signature might be considered as a promising and functional biomarker for BC diagnosis.

Long noncoding RNA LINC01278 favors the progression of osteosarcoma via modulating miR-133a-3p/PTHR1 signaling

As one of the most aggressive malignancies, osteosarcoma has high risks of death. Although long noncoding RNAs (lncRNAs) may promote the osteosarcoma progression as verified, the potential molecular mechanism of lncRNAs in osteosarcoma remains unknown. Herein, we analyzed lncRNA microarray of osteosarcoma and selected LINC01278 as the study object. Then, we found that the expression of LINC01278 tested by quantitative reverse-transcription polymerase chain reaction was enhanced in tumor tissues compared with the para-carcinoma tissues and related to clinical stage, distant metastasis in osteosarcoma. In addition, the clinical outcomes were poor in osteosarcoma patients with high LINC01278 level. Moreover, LINC01278 promoted proliferation and restrained apoptosis in osteosarcoma cells. Afterward, mechanistic studies turned out that LINC01278 was a competing endogenous RNA of parathyroid hormone type 1 receptor (PTHR1) in osteosarcoma by sponging miR-133a-3p, which was considered as a tumor inhibitor in osteosarcoma. Furthermore, PTHR1 downregulation restored the impacts of inhibited miR-133a-3p on the processes in osteosarcoma cells. Our findings clarified that the carcinogenic effect of LINC01278 in osteosarcoma was mediated through miR-133a-3p/PTHR1 signaling, creating a novel insight into good targets for the therapy and prognosis of osteosarcoma.

Exosomal microRNAs as liquid biopsy biomarkers in prostate cancer

Prostate cancer (PCa) is the most commonly diagnosed solid-organ cancer in males. The PSA testing may cause overdiagnosis and overtreatment for PCa patients. There is an urgent need for new biomarkers with greater discriminative precision for diagnosis and risk-stratification, to select for prostate biopsy and treatment of PCa. Liquid biopsy is a promising field with the potential to provide comprehensive information on the genetic landscape at diagnosis and to track genomic evolution over time in order to tailor the therapeutic choices at all stages of PCa. Exosomes, containing RNAs, DNAs and proteins, have been shown to be involved in tumour progression and a rich potential source of tumour biomarkers, especially for profiling analysis of their miRNAs content. In this review, we summarise the exosomal miRNAs in PCa diagnosis, prognosis and management, and further discuss their possible technical challenges associated with isolating PCa-specific exosomes.

MicroRNA-181a-5p Regulates Inflammatory Response of Macrophages in Sepsis

The aim of this study was to evaluate the role of miR-181a-5p in sepsis, and to further explore the molecular mechanism. RAW 264.7 cells were stimulated with 1 μg/ml LPS for 4 hours. Firstly, qRT-PCR and ELISA was adopted to evaluate the expression of miR-181a-5p and p ro-inflammatory cytokines in RAW 264.7 macrophages a fter LPS stimulation. Results showed that pro-inflammatory cytokines and miR-181a-5p were significantly increased after LPS treatment. Then, we identified that sirtuin-1 (SIRT1) was a direct target of miR-181a-5p and it was down-regulated in LPS treated RAW264.7 macrophages. Furthermore, the data suggested that the miR-181a-5p inhibitor significantly inhibited LPS enhanced inflammatory cytokines expression and NF-κB pathway activation, and these changes were eliminated by SIRT1 silencing. Moreover, the role of the miR-181a-5p inhibitor on sepsis was studied in vivo. We found that the miR-181a-5p inhibitor significantly decreased the secretion of inflammatory factors, and the levels of creatine (Cr), blood urea nitrogen (BUN), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in a serum for mice with sepsis. However, all the effects were reversed by SIRT1-siRNA. In summary, these results indicated that miR-181a-5p was involved in sepsis through regulating the inflammatory response by targeting SIRT1, suggesting that miR-181a-5p may be a potential target for the treatment of sepsis.

The presence of extracellular microRNAs in the media of cultured Drosophila cells

While regulatory RNA pathways, such as RNAi, have commonly been described at an intracellular level, studies investigating extracellular RNA species in insects are lacking. In the present study, we demonstrate the presence of extracellular microRNAs (miRNAs) in the cell-free conditioned media of two Drosophila cell lines. More specifically, by means of quantitative real-time PCR (qRT-PCR), we analysed the presence of twelve miRNAs in extracellular vesicles (EVs) and in extracellular Argonaute-1 containing immunoprecipitates, obtained from the cell-free conditioned media of S2 and Cl.8 cell cultures. Next-generation RNA-sequencing data confirmed our qRT-PCR results and provided evidence for selective miRNA secretion in EVs. To our knowledge, this is the first time that miRNAs have been identified in the extracellular medium of cultured cells derived from insects, the most speciose group of animals.

Microarray analysis of miRNA expression profiles following whole body irradiation in a mouse model

CONTEXT

Accidental exposure to life-threatening radiation in a nuclear event is a major concern; there is an enormous need for identifying biomarkers for radiation biodosimetry to triage populations and treat critically exposed individuals.

OBJECTIVE

To identify dose-differentiating miRNA signatures from whole blood samples of whole body irradiated mice.

METHODS

Mice were whole body irradiated with X-rays (2 Gy-15 Gy); blood was collected at various time-points post-exposure; total RNA was isolated; miRNA microarrays were performed; miRNAs differentially expressed in irradiated vs. unirradiated controls were identified; feature extraction and classification models were applied to predict dose-differentiating miRNA signature.

RESULTS

We observed a time and dose responsive alteration in the expression levels of miRNAs. Maximum number of miRNAs were altered at 24-h and 48-h time-points post-irradiation. A 23-miRNA signature was identified using feature selection algorithms and classifier models. An inverse correlation in the expression level changes of miR-17 members, and their targets were observed in whole body irradiated mice and non-human primates.

CONCLUSION

Whole blood-based miRNA expression signatures might be used for predicting radiation exposures in a mass casualty nuclear incident.

Investigating Pathogenic and Hepatocarcinogenic Mechanisms from Normal Liver to HCC by Constructing Genetic and Epigenetic Networks via Big Genetic and Epigenetic Data Mining and Genome-Wide NGS Data Identification

The prevalence of hepatocellular carcinoma (HCC) is still high worldwide because liver diseases could develop into HCC. Recent reports indicate nonalcoholic fatty liver disease and nonalcoholic steatohepatitis (NAFLD&NASH) and primary biliary cirrhosis and primary sclerosing cholangitis (PBC&PSC) are significant of HCC. Therefore, understanding the cellular mechanisms of the pathogenesis and hepatocarcinogenesis from normal liver cells to HCC through NAFLD&NASH or PBC&PSC is a priority to prevent the progression of liver damage and reduce the risk of further complications. By the genetic and epigenetic data mining and the system identification through next-generation sequencing data and its corresponding DNA methylation profiles of liver cells in normal, NAFLD&NASH, PBC&PSC, and HCC patients, we identified the genome-wide real genetic and epigenetic networks (GENs) of normal, NAFLD&NASH, PBC&PSC, and HCC patients. In order to get valuable insight into these identified genome-wide GENs, we then applied a principal network projection method to extract the corresponding core GENs for normal liver cells, NAFLD&NASH, PBC&PSC, and HCC. By comparing the signal transduction pathways involved in the identified core GENs, we found that the hepatocarcinogenesis through NAFLD&NASH was induced through DNA methylation of HIST2H2BE, HSPB1, RPL30, and ALDOB and the regulation of miR-21 and miR-122, and the hepatocarcinogenesis through PBC&PSC was induced through DNA methylation of RPL23A, HIST2H2BE, TIMP1, IGF2, RPL30, and ALDOB and the regulation of miR-29a, miR-21, and miR-122. The genetic and epigenetic changes in the pathogenesis and hepatocarcinogenesis potentially serve as potential diagnostic biomarkers and/or therapeutic targets.

Methodological Approaches to Study Extracellular Vesicle miRNAs in Epstein⁻Barr Virus-Associated Cancers

Epstein Barr-virus (EBV) was the first virus identified to be associated with human cancer in 1964 and is found ubiquitously throughout the world's population. It is now established that EBV contributes to the development and progression of multiple human cancers of both lymphoid and epithelial cell origins. EBV encoded miRNAs play an important role in tumor proliferation, angiogenesis, immune escape, tissue invasion, and metastasis. Recently, EBV miRNAs have been found to be released from infected cancer cells in extracellular vesicles (EVs) and regulate gene expression in neighboring uninfected cells present in the tumor microenvironment and possibly at distal sites. As EVs are abundant in many biological fluids, the viral and cellular miRNAs present within EBV-modified EVs may serve as noninvasion markers for cancer diagnosis and prognosis. In this review, we discuss recent advances in EV isolation and miRNA detection, and provide a complete workflow for EV purification from plasma and deep-sequencing for biomarker discovery.

Simultaneous isolation and preconcentration of exosomes by ion concentration polarization

Exosomes carry microRNA biomarkers, occur in higher abundance in cancerous patients than in healthy ones, and because they are present in most biofluids, including blood and urine, these can be obtained noninvasively. Standard laboratory techniques to isolate exosomes are expensive, time consuming, provide poor purity, and recover on the order of 25% of the available exosomes. We present a new microfluidic technique to simultaneously isolate exosomes and preconcentrate them by electrophoresis using a high transverse local electric field generated by ion-depleting ion-selective membrane. We use pressure-driven flow to deliver an exosome sample to a microfluidic chip such that the transverse electric field forces them out of the cross flow and into an agarose gel which filters out unwanted cellular debris while the ion-selective membrane concentrates the exosomes through an enrichment effect. We efficiently isolated exosomes from 1× PBS buffer, cell culture media, and blood serum. Using flow rates from 150 to 200 μL/h and field strengths of 100 V/cm, we consistently captured between 60 and 80% of exosomes from buffer, cell culture media, and blood serum as confirmed by both fluorescence spectroscopy and nanoparticle tracking analysis. Our microfluidic chip maintained this recovery rate for more than 20 min with a concentration factor of 15 for 10 min of isolation.

MicroRNAs in metabolism

MicroRNAs (miRNAs) have within the past decade emerged as key regulators of metabolic homoeostasis. Major tissues in intermediary metabolism important during development of the metabolic syndrome, such as β-cells, liver, skeletal and heart muscle as well as adipose tissue, have all been shown to be affected by miRNAs. In the pancreatic β-cell, a number of miRNAs are important in maintaining the balance between differentiation and proliferation (miR-200 and miR-29 families) and insulin exocytosis in the differentiated state is controlled by miR-7, miR-375 and miR-335. MiR-33a and MiR-33b play crucial roles in cholesterol and lipid metabolism, whereas miR-103 and miR-107 regulates hepatic insulin sensitivity. In muscle tissue, a defined number of miRNAs (miR-1, miR-133, miR-206) control myofibre type switch and induce myogenic differentiation programmes. Similarly, in adipose tissue, a defined number of miRNAs control white to brown adipocyte conversion or differentiation (miR-365, miR-133, miR-455). The discovery of circulating miRNAs in exosomes emphasizes their importance as both endocrine signalling molecules and potentially disease markers. Their dysregulation in metabolic diseases, such as obesity, type 2 diabetes and atherosclerosis stresses their potential as therapeutic targets. This review emphasizes current ideas and controversies within miRNA research in metabolism.

Circulating miRNAs from blood, plasma or serum as promising clinical biomarkers in oral squamous cell carcinoma: A systematic review of current findings

The purpose of this systematic review was to summarize current findings on the use of circulating miRNAs from blood, serum and plasma as cancer biomarkers in patients with oral squamous cell carcinoma. Studies were gathered after searching four different electronic databases: PUBMED, SCOPUS, Cochrane Library and Web of Science. Additional search was carried out through cross check on bibliography of selected articles. After the selection process made by two of the authors, 16 articles met the inclusion criteria and were included in the review. Results showed that circulating miRNAs from blood, serum or plasma represent promising candidates as cancer biomarkers in patients suffering from oral cancer. The possibility to predict recurrences and metastases through follow-up quantification of candidate miRNAs represents another potential feature to be addressed in future studies. However, methodological standardization and uniform sampling is needed to increase the power and accuracy of results.

Insights into the potential use of microRNAs as a novel class of biomarkers in esophageal cancer

MicroRNAs (abbreviated miRNAs) have been demonstrated to be involved in tumorigenesis and cancer development and proposed as promising biomarkers in cancer diagnosis. Numerous studies have observed the aberrant expression of miRNAs in esophageal cancer. However, there are some discrepant results. Thus, we conducted this meta-analysis to identify the overall accuracy of miRNAs in the diagnosis of esophageal cancer. A comprehensive literature search was conducted in PubMed and other databases using combinations of key words. The summary receiver operator characteristic curves were plotted to assess the overall diagnostic performance of miRNAs. Chi-squared and I(2) tests were used to assess the heterogeneity between studies. Additionally, we conducted subgroup and sensitivity analyses to analyze the potential sources of heterogeneity. In total, 33 studies from 12 articles were available in this meta-analysis. The pooled sensitivity, specificity, positive and negative likelihood ratio (PLR, NLR) diagnostic odds ratio, and area under the curve were 0.80, 0.80, 4.0, 0.25, 16, and 0.87, respectively. Subgroup analyses based on the sample types (saliva-, serum- and plasma-based) showed no differences in the diagnostic accuracy of each subgroup. An independent meta-analysis of eight articles was conducted to evaluate the diagnostic accuracy of miRNAs in patients with esophageal squamous cell carcinoma, with a pooled sensitivity of 0.77, specificity of 0.83, PLR of 4.4, NLR of 0.27, diagnostic odds ratio of 16, and area under the curve of 0.87. In conclusion, this meta-analysis demonstrates the feasibility of using miRNAs as non-invasive biomarkers to discriminate esophageal cancer from healthy controls. However, further high-quality studies on more clearly defined esophageal cancer patient are needed to confirm our conclusion.

MicroRNA in rectal cancer

In rectal cancer, one of the most common cancers worldwide, the proper staging of the disease determines the subsequent therapy. For those with locally advanced rectal cancer, a neoadjuvant chemoradiotherapy (CRT) is recommended before any surgery. However, response to CRT ranges from complete response (responders) to complete resistance (non-responders). To date we are not able to separate in advance the first group from the second, due to the absence of a valid biomarker. Therefore all patients receive the same therapy regardless of whether they reap benefits. On the other hand almost all patients receive a surgical resection after the CRT, although a watch-and-wait procedure or an endoscopic resection might be sufficient for those who responded well to the CRT. Being highly conserved regulators of gene expression, microRNAs (miRNAs) seem to be promising candidates for biomarkers. Many studies have been analyzing the miRNAs expressed in rectal cancer tissue to determine a specific miRNA profile for the ailment. Unfortunately, there is only a small overlap of identified miRNAs between different studies, posing the question as to whether different methods or differences in tissue storage may contribute to that fact or if the results simply are not reproducible, due to unknown factors with undetected influences on miRNA expression. Other studies sought to find miRNAs which correlate to clinical parameters (tumor grade, nodal stage, metastasis, survival) and therapy response. Although several miRNAs seem to have an impact on the response to CRT or might predict nodal stage, there is still only little overlap between different studies. We here aimed to summarize the current literature on rectal cancer and miRNA expression with respect to the different relevant clinical parameters.

MicroRNAs as Biomarkers for Diagnosis, Prognosis and Theranostics in Prostate Cancer

Prostate cancer (PC) includes several phenotypes, from indolent to highly aggressive cancer. Actual diagnostic and prognostic tools have several limitations, and there is a need for new biomarkers to stratify patients and assign them optimal therapies by taking into account potential genetic and epigenetic differences. MicroRNAs (miRNAs) are small sequences of non-coding RNA regulating specific genes involved in the onset and development of PC. Stable miRNAs have been found in biofluids, such as serum and plasma; thus, the measurement of PC-associated miRNAs is emerging as a non-invasive tool for PC detection and monitoring. In this study, we conduct an in-depth literature review focusing on miRNAs that may contribute to the diagnosis and prognosis of PC. The role of miRNAs as a potential theranostic tool in PC is discussed. Using a meta-analysis approach, we found a group of 29 miRNAs with diagnostic properties and a group of seven miRNAs with prognostic properties, which were found already expressed in both biofluids and PC tissues. We tested the two miRNA groups on The Cancer Genome Atlas dataset of PC tissue samples with a machine-learning approach. Our results suggest that these 29 miRNAs should be considered as potential panel of biomarkers for the diagnosis of PC, both as in vivo non-invasive test and ex vivo confirmation test.

Circulating microRNAs in nonalcoholic fatty liver disease

Liver biopsy is currently recognized as the most accurate method for diagnosing and staging nonalcoholic fatty liver disease (NAFLD). However, this procedure is typically performed when disease has progressed to clinically significant stages, thereby limiting early diagnosis of patients who are at high risk for development of liver- and cardiovascular-related morbidity and mortality. Recently, microRNAs (miRNAs), short, noncoding RNAs that regulate gene expression, have been associated with histological features of NAFLD and are readily detected in the circulation. As such, miRNAs are emerging as potentially useful noninvasive markers with which to follow the progression of NAFLD. In this article, we present the evidence linking circulating miRNAs with NAFLD and discuss the potential value of circulating miRNA profiles in the development of improved methods for NAFLD diagnosis and clinical monitoring of disease progression.

Nonfunctional ingestion of plant miRNAs in silkworm revealed by digital droplet PCR and transcriptome analysis

Since a plant miRNA (miR168) cross-regulating a mammalian transcript was reported, miRNA-mediated cross-kingdom communication has become one of the most compelling but controversial topics. In the present study, we used silkworm and mulberry, which is a model for studies on the interactions between the insect and its host plant, to address whether miRNA-mediated cross-kingdom communication is a common phenomenon. The results of TA clone, Sanger sequencing and droplet digital PCR demonstrated that several mulberry-derived miRNAs could enter to silkworm hemolymph and multiple tested tissues. Synthetic miR166b was also detected in hemolymph and fat body. However, the ingestion of synthetic miR166b did not play roles in silkworm physiological progress, which was revealed by RNA-seq analyses, RT-PCR, and phenotypic investigations. Mulberry miRNAs are convincingly transferred to the silkworm orally and no physiological process associated with the miRNAs was demonstrable. The results provided a new aspect of cross-kingdom miRNA transfer.

MicroRNA and pediatric tumors: Future perspectives

A better understanding of pediatric tumor biology is needed to allow the development of less toxic and more efficient therapies, as well as to provide novel reliable biomarkers for diagnosis and risk stratification. The emerging role of microRNAs in controlling key pathways implicated in tumorigenesis makes their use in diagnostics a powerful novel tool for the early detection, risk assessment and prognosis, as well as for the development of innovative anticancer therapies. This perspective would be more urgent for the clinical management of pediatric cancer. In this review, we focus on the involvement of microRNAs in the biology of the main childhood tumors, describe their clinical significance and discuss their potential use as novel therapeutic tools and targets.