Circulating MicroRNA-26a in Plasma and Its Potential Diagnostic Value in Gastric Cancer. PLoS One. 2016;11:e0151345. [PMID: 27010210 PMCID: PMC4806920 DOI: 10.1371/journal.pone.0151345]

Non-Coding RNA as Biomarkers and Their Role in the Pathogenesis of Gastric Cancer-A Narrative Review

Non-coding RNAs (ncRNAs) represent a broad family of molecules that regulate gene expression, including microRNAs, long non-coding RNAs and circular RNAs, amongst others. Dysregulated expression of ncRNAs alters gene expression, which is implicated in the pathogenesis of several malignancies and inflammatory diseases. Gastric cancer is the fifth most frequently diagnosed cancer and the fourth most common cause of cancer-related death. Studies have found that altered expression of ncRNAs may contribute to tumourigenesis through regulating proliferation, apoptosis, drug resistance and metastasis. This review describes the potential use of ncRNAs as diagnostic and prognostic biomarkers. Moreover, we discuss the involvement of ncRNAs in the pathogenesis of gastric cancer, including their interactions with the members of major signalling pathways.

Role of MicroRNA in Hypoxic Tumours and their Potential as Biomarkers for Early Detection of Cancer

Hypoxia is a pathophysiological condition characterized by oxygen deficiency in tissues, which negatively affects normal biological functions. It is a typical microenvironment character of almost all solid tumours. Noncoding RNA are small functional RNA molecules that regulate gene expression at chromatin and posttranscriptional levels. Micro-RNAs (miRNAs) are a type of noncoding RNA and are ~12-22 nucleotides long that are crucial in regulating gene expression by partnering with the mRNAs of protein-coding genes. It is widely reported that miRs play an important role in various key processes and pathways during tumour formation, as well as advancement in hypoxic tumors by influencing the HIF pathway. The role of miRNAs in hypoxic tumours, namely in pancreatic, kidney, breast, lung and colorectal, are described. These miRNAs have immense potential as diagnostic and prognostic biomarkers for early cancer detection.

Development and Validation of a Novel Circulating miRNA-Based Diagnostic Score for Early Detection of Hepatocellular Carcinoma

BACKGROUND

With the rise of liquid biopsy in oncology, circulating miRNAs have become one of the most promising noninvasive biomarkers for early detection of hepatocellular carcinoma (HCC). However, a reliable HCC-related circulating miRNA panel and corresponding diagnostic model remain to be explored.

METHODS

Five large public datasets related to intact miRNA profiles in the serum or tumors of HCC patients were included and divided into training cohorts (GSE113740 and TCGA-LIHC) and validation cohorts (GSE112264, GSE113486 and GSE106817). Compared with non-cancer controls and high-risk patients, key miRNAs dysregulated in both the serum and tumors of HCC patients were identified by differential expression analysis and overlapping analysis. The corresponding diagnostic model was constructed by LASSO logistic regression and evaluated by receiver operating characteristic curves and a nomogram with calibration plot.

RESULTS

A distinctive panel of HCC-related circulating miRNAs, including three upregulated miRNAs (miR-184, miR-532-5p, miR-221-3p) and three downregulated miRNAs (miR-5589-5p, let-7b-3p, miR-26b-3p), were rigorously screened out, all of which displayed significant discriminability between HCC patients and controls (all P < 0.05). In addition, a reliable six-circulating miRNA-based diagnostic score was constructed and displayed robust diagnostic ability for HCC (particularly for early-stage HCC) (AUC = 0.9535, P < 0.05) compared with that of the serum α-fetoprotein test. Importantly, its efficacy was sufficiently validated in three independent datasets (AUC = 0.9780/0.9961/0.9681, all P < 0.05). Furthermore, a visual nomogram based on the diagnostic score was correspondingly established to strengthen its clinical applicability.

CONCLUSION

The six-circulating miRNA-based diagnostic score may be a reliable noninvasive biomarker for early-stage HCC screening and dynamic monitoring of postoperative recurrence.

Identification of Combinations of Plasma lncRNAs and mRNAs as Potential Biomarkers for Precursor Lesions and Early Gastric Cancer

Patients with gastric cancer (GC) are usually first diagnosed at an advanced stage due to the absence of obvious symptoms at an early GC (EGC) stage. Therefore, it is necessary to identify an effective screening method to detect precursor lesions of GC (PLGC) and EGC to increase the 5-year survival rate of patients. Cell-free RNA, as a biomarker, has shown potential in early diagnosis, personalised treatment, and prognosis of cancer. In this study, six RNAs (CEBPA-AS1, INHBA-AS1, AK001058, UCA1, PPBP, and RGS18) were analysed via real-time quantitative polymerase chain reaction (RT-qPCR) using the plasma of patients with EGC and PLGC to identify diagnostic biomarkers. The receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic accuracy. Among the six RNAs, four lncRNAs (CEBPA-AS1, INHBA-AS1, AK001058, and UCA1) were upregulated and two mRNAs (PPBP and RGS18) were downregulated in the plasma of patients with PLGC and EGC. According to the findings of the ROC analysis, the four-RNA combination of INHBA-AS1, AK001058, UCA1, and RGS18 had the highest area under the curve (AUC) value for determining risk of GC in patients with PLGC and the six-RNA combination including CEBPA-AS1, INHBA-AS1, AK001058, UCA1, PPBP, and RGS18 had the highest AUC value for determining the risk of GC in patients with EGC. The results suggest the potential usefulness of noninvasive biomarkers for the molecular diagnosis of GC at earlier stages.

Prediction of Blood miRNA-mRNA Regulatory Network in Gastric Cancer

Background

The aim of the study was to suggest a high specific and sensitive blood biomarker for early GC diagnosis.

Methods

the expression data of miRNAs and mRNAs were collected from the blood samples of the GC patients based on literature mining. Bioinformatics tools and databases (PANTHER, TargetScan, miRTarBase, miRDB, STRING, and Cytoscape) were used to predict the regulatory relationship. Subsequently, expression level of the selected miRNA was evaluated in the blood samples of gastritis patients to recognize the common miRNA between the GC and gastritis patients.

Results

Analysis of 40 target genes by MCODE (installed in Cytoscape software) indicated 4 hub genes (WWP1, SKP2, KLHL42, and FBXO11) as a significant cluster in the PPI network related to miR-21, with Node Score Cutoff: 0.2, Degree Cutoff: 2 and K-Core: 2. In addition, the miRNA RT-qPCR results showed that, the expression level of miR-21 was significantly higher in gastritis group compared to the healthy group (p< 0.05).

Conclusion

the present study clearly demonstrated the increasing level of blood miR-21 among the gastritis patients infected by H. pylori. Therefore, the altered miRNAs, especially overexpression of onco-miRs, may identify a potential link between miRNAs and pathogenesis of the H. pylori-related complications.

Plasma miR-6089 as potential diagnostic biomarker for retinoblastoma

OBJECTIVE

The purpose of this study was to screen target miRNA related to RB and explore the expression levels of target miRNA in RB and its potential value of diagnosis.

METHODS

The Affymetrix GeneChip miRNA 4.0 Array was used to screen the differential miRNAs in the plasma of 5 RB patients before and after intravenous chemotherapy, and the most significant down-regulated miRNA was selected for target miRNA. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) is used to verify the expression levels of plasma target miRNA in 30 RB patients. Then, qRT-PCR was performed to further verify the expression of target miRNA in plasma of RB patients and RB tumor tissues. Finally, receiver-operating-characteristic (ROC) curve and the area under the ROC curve (AUC) were used to evaluate the diagnostic power of plasma target miRNA.

RESULTS

The miRNA Array obtain 8 core miRNAs, 1 up-regulated and 7 down-regulated, of which miR-6089 was the most significantly down-regulated. Plasma miR-6089 levels were significantly up-regulated in RB patients. Besides, in RB tumor tissues, miR-6089 levels were also obviously up-regulated. After intravenous chemotherapy, the expression of plasma miR-6089 was significantly decreased. Furthermore, ROC curve analysis showed that miR-6089 in the plasma had a good sensitivity and specificity for distinguishing RB from the healthy control group.

CONCLUSIONS

MiR-6089 may be considered as a novel potential diagnostic biomarker for RB.

TRIAL REGISTRATION NUMBER

ChiCTR2000040154; date of registration: 2020/11/22; retrospectively registered.

Novel Biomarkers in the Diagnosis of Benign and Malignant Gastrointestinal Diseases

BACKGROUND

Various noninvasive biomarkers have been used in the diagnosis, prognosis, and treatment of different gastrointestinal (GI) diseases for years. Novel technological developments and profound perception of molecular processes related to GI diseases over the last decade have allowed researchers to evaluate genetic, epigenetic, and many other potential molecular biomarkers in different diseases and clinical settings. Here, we present a review of recent and most relevant articles in order to summarize major findings on novel biomarkers in the diagnosis of benign and malignant GI diseases.

SUMMARY

Genetic variations, noncoding RNAs (ncRNAs), cell-free DNA (cfDNA), and microbiome-based biomarkers have been extensively analyzed as potential biomarkers in benign and malignant GI diseases. Multiple single-nucleotide polymorphisms have been linked with a number of GI diseases, and these observations are further being used to build up disease-specific genetic risk scores. Micro-RNAs and long ncRNAs have a large potential as noninvasive biomarkers in the management of inflammatory bowel diseases and GI tumors. Altered microbiome profiles were observed in multiple GI diseases, but most of the findings still lack translational clinical application. As of today, cfDNA appears to be the most potent biomarker for early detection and screening of GI cancers. Key Messages: Novel noninvasive molecular biomarkers show huge potential as useful tools in the diagnostics and management of different GI diseases. However, the use of these biomarkers in real-life clinical practice still remains limited, and further large studies are needed to elucidate the ultimate role of these potential noninvasive clinical tools.

Identifying Novel Biomarkers Ready for Evaluation in Low-Prevalence Populations for the Early Detection of Upper Gastrointestinal Cancers: A Systematic Review

Introduction

Detecting upper gastrointestinal (GI) cancers in primary care is challenging, as cancer symptoms are common, often non-specific, and most patients presenting with these symptoms will not have cancer. Substantial investment has been made to develop biomarkers for cancer detection, but few have reached routine clinical practice. We aimed to identify novel biomarkers for upper GI cancers which have been sufficiently validated to be ready for evaluation in low-prevalence populations.

Methods

We systematically searched MEDLINE, Embase, Emcare, and Web of Science for studies published in English from January 2000 to October 2019 (PROSPERO registration CRD42020165005). Reference lists of included studies were assessed. Studies had to report on second measures of diagnostic performance (beyond discovery phase) for biomarkers (single or in panels) used to detect pancreatic, oesophageal, gastric, and biliary tract cancers. We included all designs and excluded studies with less than 50 cases/controls. Data were extracted on types of biomarkers, populations and outcomes. Heterogeneity prevented pooling of outcomes.

Results

We identified 149 eligible studies, involving 22,264 cancer cases and 49,474 controls. A total of 431 biomarkers were identified (183 microRNAs and other RNAs, 79 autoantibodies and other immunological markers, 119 other proteins, 36 metabolic markers, 6 circulating tumour DNA and 8 other). Over half (n = 231) were reported in pancreatic cancer studies. Only 35 biomarkers had been investigated in at least two studies, with reported outcomes for that individual marker for the same tumour type. Apolipoproteins (apoAII-AT and apoAII-ATQ), and pepsinogens (PGI and PGII) were the most promising biomarkers for pancreatic and gastric cancer, respectively.

Conclusion

Most novel biomarkers for the early detection of upper GI cancers are still at an early stage of matureness. Further evidence is needed on biomarker performance in low-prevalence populations, in addition to implementation and health economic studies, before extensive adoption into clinical practice can be recommended.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-020-01571-z) contains supplementary material, which is available to authorized users.

Expression and Bioinformatics-Based Functional Analysis of UAP1 in Lung Adenocarcinoma

Background

Lung adenocarcinoma (LAD) is the most prevalent type of lung cancer. The abnormal expression of UDP-N-acetylglucosamine pyrophosphorylase 1 (UAP1) has been reported to be involved in many biological processes of cancer cells, but the expression of UAP1 in LAD is unclear.

Methods

Bioinformatics was used to analyse the LAD gene expression data and related clinical data in the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. DAVID6.8 was used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) signal pathway enrichment analyses of UAP1 expression-related genes. The STRING database was used to analyse protein-protein interaction (PPI) networks. RNA isolation and reverse transcription-quantitative polymerase chain reaction (RT‑qPCR) assay were used to detect the expression of UAP1 in tissues and blood samples.

Results

We found that UAP1 was upregulated in LAD tissues and correlated with poor clinical outcome. GO analysis showed that these genes were enriched in biological processes and functions including intracellular transport, cellular protein catabolic process, and mitochondria (P<0.05). The KEGG pathway analysis showed that these genes were mainly involved in the signalling pathways of amino sugar and nucleotide sugar metabolism, the aminoacyl-tRNA biosynthesis signalling pathway, and protein export (P<0.05). The PPI analysis showed that EPRS, COPB1, CCT3, ALDH18A1 and ARF1 genes had marked or potential interaction with UAP1 (P<0.01). In addition, UAP1 expression was upregulated in LAD tissues compared to normal tissues. High levels of UAP1 expression were associated with larger tumour sizes and later TNM stages. RT‑qPCR detection in serum further showed that UAP1 expression was upregulated in the plasma of LAD patients compared to that of healthy volunteers. High expression of UAP1 in serum suggests a poor prognosis for LAD patients.

Conclusion

UAP1 could be a novel diagnostic biomarker and a promising therapeutic target for LAD.

circCUL2 regulates gastric cancer malignant transformation and cisplatin resistance by modulating autophagy activation via miR-142-3p/ROCK2

Background

Circular RNAs (circRNAs) are a class of noncoding RNAs (ncRNAs) and can modulate gene expression by binding to miRNAs; further, circRNAs have been shown to participate in several pathological processes. However, the expression and biological function of circCUL2 in gastric cancer (GC) remains largely unknown.

Methods

circRNA microarrays and quantitative real-time PCR (qRT-PCR) were used to identify differentially expressed circRNAs in GC tissues and cell lines. circCUL2 knockdown and overexpression were performed to indicate the functional role of circCUL2 in vitro and in vivo. The expression and regulation of circCUL2, miR-142-3p and ROCK2 were evaluated using fluorescence in situ hybridization (FISH), dual-luciferase assays, RNA pull-down assays, RNA immunoprecipitation (RIP) and rescue experiments. Furthermore, the regulation of cisplatin sensitivity and autophagy by circCUL2/miR-142-3p/ROCK2 was demonstrated by cellular apoptosis assays, western blot, immunofluorescence and transmission electron microscopy analyses.

Results

The level of circCUL2, which is stable and cytoplasmically localized, was significantly reduced in GC tissues and cells. Overexpressed circCUL2 inhibited malignant transformation in vitro and tumorigenicity in vivo. In the AGS and SGC-7901 cell lines, circCUL2 sponged miR-142-3p to regulate ROCK2, thus modulating tumor progression. Furthermore, in the AGS/DDP and SGC-7901/DDP cell lines, circCUL2 regulated cisplatin sensitivity through miR-142-3p/ROCK2-mediated autophagy activation.

Conclusion

circCUL2 may function as a tumor suppressor and regulator of cisplatin sensitivity through miR-142-3p/ROCK2-mediated autophagy activation, which could be a key mechanism and therapeutic target for GC.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12943-020-01270-x.

A Traditional Korean Diet Alters the Expression of Circulating MicroRNAs Linked to Diabetes Mellitus in a Pilot Trial

The traditional Korean diet (K-diet) is considered to be healthy and circulating microRNAs (miRs) have been proposed as useful markers or targets in diet therapy. We, therefore, investigated the metabolic influence of the K-diet by evaluating the expression of plasma and salivary miRs. Ten women aged 50 to 60 years were divided into either a K-diet or control diet (a Westernized Korean diet) group. Subjects were housed in a metabolic unit-like condition during the two-week dietary intervention. Blood and saliva samples were collected before and after the intervention, and changes in circulating miRs were screened by an miR array and validated by individual RT-qPCRs. In the K-diet group, eight plasma miRs were down-regulated by array (p < 0.05), out of which two miRs linked to diabetes mellitus, hsa-miR26a-5p and hsa-miR126-3p, were validated (p < 0.05). Among five down-regulated salivary miRs, hsa-miR-92-3p and hsa-miR-122a-5p were validated, which are associated with diabetes mellitus, acute coronary syndrome and non-alcoholic fatty liver disease. In the control diet group, validated were down-regulated plasma hsa-miR-25-3p and salivary hsa-miR-31-5p, which are associated with diabetes mellitus, adipogenesis and obesity. The K-diet may influence the metabolic conditions associated with diabetes mellitus, as evidenced by changes in circulating miRs, putative biomarkers for K-diet.

miR-26a-5p Inhibit Gastric Cancer Cell Proliferation and Invasion Through Mediated Wnt5a

Purpose

Gastric cancer (GC) is a malignant disease of digestive tract. Clinically, radiation therapy is widely applied in treating GC, while with undesirable outcome due to tumor re-proliferation and recurrence and metastasis after radiation. Therefore, it is crucial to explore potential molecular mechanisms to develop therapeutic strategies. The present study found that miR-26a-5p has low expression in GC patients and could regulate Wnt5a to inhibit tumor growth, which was a potential therapeutic target for GC. To explore the expression and related mechanism of miR-26a-5p and Wnt5a in GC.

Patients and Methods

MiR-26a-5p and Wnt5a were extracted from the transcriptome data of GC downloaded from TCGA database for analysis. The expression levels of miR-26a-5p and Wnt5a in patients’ tissues and serum were detected by qRT-PCR, and their correlation with patients’ pathological data and survival was analyzed. In addition, miR-26a-5p and Wnt5a overexpression and inhibition vectors were transfected into cells to observe the effects on the proliferation, invasion and apoptosis of GC cells. The relationship between miR-26a-5p and Wnt5a was analyzed by dual luciferase report.

Results

The database and clinical samples showed that miR-26a-5p level was low while Wnt5a was high in GC. MiR-26a-5p level decreased in patients with stage III+IV, lymphatic metastasis and tumor ≥3cm, and Wnt5a was contrary to that of the miR-26a-5p, with diagnostic value. Overexpressed miR-26a-5p and inhibited Wnt5a enhanced apoptosis, decreased proliferation and invasion, reduced Bcl-2 and β-catenin proteins, and elevated Caspase 3, E-cadherin and Bax proteins, while inhibited miR-26a-5p and over-expressed Wnt5a showed the opposite results. Dual luciferase report confirmed that miR-26a-5p targeted to regulate Wnt5a, and rescue experiments found that these effects could be counteracted by reducing miR-26a-5p level.

Conclusion

Overexpressed miR-26a-5p can inhibit Wnt5a expression, promote cell apoptosis, and suppress cell proliferation and invasion in GC.

A novel urinary microRNA biomarker panel for detecting gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common causes of cancer deaths worldwide; however, reliable and non-invasive screening methods for GC are not established. Therefore, we conducted this study to develop a biomarker for GC detection, consisting of urinary microRNAs (miRNAs).

METHODS

We matched 306 participants by age and sex [153 pairs consisting of patients with GC and healthy controls (HCs)], then randomly divided them across three groups: (1) the discovery cohort (4 pairs); (2) the training cohort (95 pairs); and (3) the validation cohort (54 pairs).

RESULTS

There were 22 urinary miRNAs with significantly aberrant expressions between the two groups in the discovery cohort. Upon multivariate analysis of the training cohort, urinary expression levels of miR-6807-5p and miR-6856-5p were significantly independent biomarkers for diagnosis of GC, in addition to Helicobacter pylori (H. pylori) status. A diagnostic panel that combined these 2 miRNAs and H. pylori status distinguished between HC and GC samples with an area under the curve (AUC) = 0.736. In the validation cohort, urinary miR-6807-5p and miR-6856-5p showed significantly higher expression levels in the GC group, and the combination biomarker panel of miR-6807-5p, miR-6856-5p, and H. pylori status also showed excellent performance (AUC = 0.885). In addition, this biomarker panel could distinguish between HC and stage I GC patients with an AUC = 0.748. Urinary expression levels of miR-6807-5p and miR-6856-5p significantly decreased to undetectable level after curative resection of GC.

CONCLUSIONS

This novel biomarker panel enables early and non-invasive detection of GC.

The lncRNA UCA1 promotes proliferation, migration, immune escape and inhibits apoptosis in gastric cancer by sponging anti-tumor miRNAs

Background

UCA1 is a long non-coding RNA which was found overexpressed in various human cancers including gastric cancer (GC). It is identified that UCA1 promotes GC cells proliferation, migration and invasion, however, the role of UCA1 during the processes of immune escape is still not unclear.

Methods

We collected 40 paired GC and non-tumor tissue samples. The level of UCA1 in GC and control tissue samples were determined by in situ hybridization and qRT-PCR. Cell viability was determined by MTT assay. GC cells’ migration capacities were examined by transwell assay. To understand the roles of UCA1 during immune escape, wildtype or UCA1 KO GC cells co-cultured with peripheral blood mononuclear cells or cytokine-induced killer cells in vitro. Mouse model was used to examine the function of UCA1 in vivo.

Results

UCA1 promoted GC cells proliferation and migration, and inhibit apoptosis. UCA1 repressed miR-26a/b, miR-193a and miR-214 expression through direct interaction and then up-regulated the expression of PDL1. UCA1-KO GC cells could induce a higher IFNγ expression when co-cultured with peripheral blood mononuclear cells (PBMCs), and have a lower survival rate when co-cultured with cytokine-induced killer (CIK) cells in vitro. UCA1-KO GC cells formed smaller tumors, had higher miR-26a, −26b, −193a and − 214 level, reduced cell proliferation and increased apoptosis in xenograft mouse model.

Conclusions

UCA1 overexpression protected PDL1 expression from the repression of miRNAs and contributed to the GC cells immune escape. UCA1 could serve as a potential novel therapeutic target for GC treatment.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-1032-0) contains supplementary material, which is available to authorized users.

The diagnostic value of circulating microRNAs as a biomarker for gastric cancer: A meta‑analysis

Recently, cancer research microRNA studies have drawn great attention. However, the results of these studies have been inconsistent and variable regarding the availability of circulating miRNAs in gastric cancer (GC) diagnosis. Thus, results should be interpreted cautiously. The purpose of the present study was to assess the diagnostic performance of circulating miRNAs in GC diagnosis. We conducted a systematic and comprehensive approach for the inclusion of studies. The sensitivity, specificity, and diagnostic odds ratio were pooled with random effects models, and a summary of receiver operator characteristic (SROC) curves were plotted. The potential heterogeneity was assessed with Q test and I2 statistics. Subgroup analyses and meta‑regressions further investigated the sources of heterogeneity. A total of 77 studies from 48 articles were eligible for the meta‑analysis. The results revealed a sensitivity of 0.76, a specificity of 0.81, and an AUC of 0.86 for gastric cancer diagnosis with circulating miRNAs. In addition, subgroup analyses indicated that multiple miRNAs assays, non‑microarray screening approaches, and serum‑based miRNA assays exhibited good diagnostic performance in contrast to a single miRNA assay, microarray expression profiling screening, and plasma‑based miRNA group analysis. The diagnostic ability of miRNAs in early stage I‑II groups and the high expression group were approximately similar to that in the stage I‑IV groups and the low expression group. For the circulating miRNAs, our meta‑analysis identified a combination of multiple miRNAs, non‑microarray chip screening, and serum‑based miRNA assays were associated with the most effective GC diagnostic performance. However, many unclear molecular mechanisms limited the accuracy of the diagnostic results, and should be interpreted with caution. Further large‑scale prospective studies are required for validating the diagnostic applicability of circulating miRNAs in gastric cancer patients.

Co-expression profiling of plasma miRNAs and long noncoding RNAs in gastric cancer patients

PURPOSE

The recent researches indicate that differential non-coding RNAs expression signatures could be associated with the pathogenesis of gastric cancer (GC). However, there are few studies focused on lncRNA-miRNAs co-expression profiling in GC patients. Therefore, in the present study the expression of H19 and MEG3 and their related miRNAs including miR-148a-3p, miR-181a-5p, miR-675-5p and miR-141-3p were determined in the plasma samples of GC patients and controls.

MATERIALS AND METHODS

This case-control study included 62 GC patients and 40 age- sex matched controls. The non-coding RNA levels were assessed by real-time PCR. Further, using in silico analysis, we identified shared targets of studied miRNAs and performed GC-associated pathway enrichment analysis.

RESULTS

Our results showed that the H19 level was significantly (P = 0.008) elevated and MEG3 expression was significantly (P = 0.002) down-regulated in GC patients compared to healthy participants. Furthermore, it was revealed that the miR-675-5p level was increased, while miR-141-3p plasma levels were significantly reduced in GC patients (P < 0.05). We did not observe a significant difference for miR-148a-3p (P = 0.682) and miR-181a-5p (P = 0.098) expression between groups. In addition, the expression levels of H19, MEG3 and miR-148a-3p were associated with some clinicopathological features of patients (P < 0.05). ROC analysis revealed that a combination of H19, MEG3 and miR-675-5p levels able to discriminate controls and GC subjects with 88.87% sensitivity and 85% specificity (AUC, 0.927; 0.85-0.96 CI, P < 0.0001).

CONCLUSION

The results of current study demonstrated that combination of H19, MEG3 and miR-675-5p expression levels could provide a potential diagnostic panel for GC.

MiRNA-BD: an evidence-based bioinformatics model and software tool for microRNA biomarker discovery

MicroRNAs (miRNAs) are small non-coding RNAs with the potential as biomarkers for disease diagnosis, prognosis and therapy. In the era of big data and biomedical informatics, computer-aided biomarker discovery has become the current frontier. However, most of the computational models are highly dependent on specific prior knowledge and training-testing procedures, very few are mechanism-guided or evidence-based. To the best of our knowledge, untill now no general rules have been uncovered and applied to miRNA biomarker screening. In this study, we manually collected literature-reported cancer miRNA biomarkers and analyzed their regulatory patterns, including the regulatory modes, biological functions and evolutionary characteristics of their targets in the human miRNA-mRNA network. Two evidences were statistically detected and used to distinguish biomarker miRNAs from others. Based on these observations, we developed a novel bioinformatics model and software tool for miRNA biomarker discovery ( http://sysbio.suda.edu.cn/MiRNA-BD/ ). In contrast to routine methods that focus on miRNA synergic functions, our method searches for vulnerable sites in the miRNA-mRNA network and considers the independent regulatory power of miRNAs, i.e., single-line regulations between miRNAs and mRNAs. The performance comparison demonstrates the generality and precision of our model, which identifies miRNA biomarkers for cancers as well as other complex diseases without training or specific prior knowledge.

MicroRNAs as non-invasive diagnostic biomarkers for gastric cancer: Current insights and future perspectives

Non-invasive diagnostic biomarkers may contribute to an early identification of gastric cancer (GC) and improve the clinical management. Unfortunately, no sensitive and specific screening biomarkers are available yet and the currently available approaches are limited by the nature of the disease. GC is a heterogenic disease with various distinct genetic and epigenetic events that occur during the multifactorial cascade of carcinogenesis. MicroRNAs (miRNAs) are commonly deregulated in gastric mucosa during the Helicobacter pylori infection and in stepwise manner from chronic gastritis, through preneoplastic conditions such as atrophic gastritis and intestinal metaplasia, to early dysplasia and invasive cancer. Identification of miRNAs in blood in 2008 led to a great interest on miRNA-based diagnostic, prognostic biomarkers in GC. In this review, we provide the most recent systematic review on the existing studies related to miRNAs as diagnostic biomarkers for GC. Here, we systematically evaluate 75 studies related to differential expression of circulating miRNAs in GC patients and provide novel view on various heterogenic aspects of the existing data and summarize the methodological differences. Finally, we highlight several important aspects crucial to improve the future translational and clinical research in the field.

Liquid biopsy provides new insights into gastric cancer

Liquid biopsies have great promise for precision medicine as they provide information about primary and metastatic tumors via a minimally invasive method. In gastric cancer patients, a large number of blood-based biomarkers have been reported for their potential role in clinical practice for screening, early diagnosis, prognostic evaluation, recurrence monitoring and therapeutic efficiency follow-up. This current review focuses on blood liquid biopsies' role and their clinical implications in gastric cancer patients, with an emphasis on circulating tumor cells (CTCs), circulating tumor DNA (ctDNA) and circulating non-coding RNAs (ncRNAs). We also provide a brief discussion of the potential and limitations of liquid biopsies use and their future use in the routine clinical care of gastric cancer.

[MicroRNA-26a and Tumor]

微小RNA（microRNAs, miRNAs）是一类由20个-22个核苷酸组成的小片段非编码RNA，通过靶向结合基因mRNA的3’非翻译区（3’-UTR）调控其表达。许多研究报道miRNAs参与肿瘤的发生发展。MiR-26a在不同的肿瘤中发挥不同的作用，在肿瘤增殖、转移侵袭、血管形成、生物代谢及诊断预后中都有作用。本文就miR-26a与肿瘤关系的研究进展进行综述。

MiRNA-491-5p inhibits cell proliferation, invasion and migration via targeting JMJD2B and serves as a potential biomarker in gastric cancer

Our previous work discovered that the histone demethylase JMJD2B (KDM4B) plays oncogenic roles in gastric carcinogenesis, but the regulatory mechanism of JMJD2B in gastric cancer has not been well defined. It has been revealed that microRNAs function as gene regulators by binding to the 3'UTR of mRNAs to inhibit gene expression. In this study, we found that miR-491-5p suppressed cell proliferation, invasion and migration by directly targeting the JMJD2B 3'UTR in gastric cancer. Moreover, miR-491-5p was decreased in GC tissues compared with adjacent normal tissues, and JMJD2B had the inverse expression pattern. In contrast to healthy individuals, GC patients had lower miR-491-5p expression in serum (P<0.0001). Our data indicate that miR-491-5p serves as a tumor suppressor in GC and might be a novel potential biomarker for the detection of gastric cancer.

Serum exosomal miR-301a as a potential diagnostic and prognostic biomarker for human glioma

PURPOSE

Exosomal miRNAs that play an important role in cell-cell communication have attracted major attention as potential diagnostic and prognostic biomarkers for various cancers. The aim of this study was to determine the diagnostic/prognostic significance of serum exosomal miR-301a in glioma patients.

METHODS

Quantitative real-time PCR was used to determine the serum exosomal expression levels of miR-301a. Kaplan-Meier survival analyses, Cox regression analyses and ROC working curve analyses were applied to assess the diagnostic and prognostic values of miR-301a in glioma patients. Also, several in vitro assays were used, including proliferation, invasion and cell signaling assays.

RESULTS

First, we established that serum exosomal miR-301a extracted from grade IV glioblastoma (GBM) patients was biologically active, i.e., promoted the proliferation and invasion of glioma-derived H4 cells. Subsequently, we found that serum exosomal miR-301a levels were significantly up-regulated in glioma patients compared to healthy controls. Additionally, we found that increased serum exosomal miR-301a levels were correlated with ascending pathological grades and lower Karnofsky performance status (KPS) scores. Importantly, we also found that the serum exosomal miR-301a levels were significantly reduced after surgical resection of primary tumors and increased again during GBM recurrence. Kaplan-Meier analysis of patients with an advanced pathological grade (III or IV) and an increased serum exosomal miR-301a level revealed a longer overall survival (OS) compared to those with a lower level (p < 0.01). Both univariate and multivariate Cox regression analyses confirmed that serum exosomal miR-301a levels are independently associated with OS. Finally, we found that miR-301a may activate the AKT and FAK signaling pathways by down regulating PTEN.

CONCLUSIONS

Our data indicate that serum exosomal miR-301a levels may reflect the cancer-bearing status and pathological changes in glioma patients. Serum exosomal miR-301a expression may serve as a novel biomarker for glioma diagnosis and as a prognostic factor for advanced grade disease.

Identification of Circulating Long Noncoding RNA Linc00152 as a Novel Biomarker for Diagnosis and Monitoring of Non-Small-Cell Lung Cancer

Objective

Long noncoding RNAs (lncRNAs) have been reported to play vital roles in non-small-cell lung cancer (NSCLC). Recently, long noncoding RNA Linc00152 has been reported to play important roles in various cancers. In this study, our aim was to investigate its expression pattern and clinical significance and further evaluate its diagnostic value for NSCLC.

Methods

The levels of Linc00152 were detected in NSCLC tissues and plasma samples by quantitative real-time PCR (qRT-PCR). Receiver operating characteristic (ROC) curves were depicted to evaluate the diagnostic value.

Results

We found that Linc00152 levels were upregulated in both NSCLC tissues and plasma samples. Plasma Linc00152 levels were significantly lower in postoperative samples than in preoperative samples. Besides, high Linc00152 expression was significantly correlated with tumor size (r = 0.293, P = 0.005) and tumor stage (r = 0.324, P = 0.011). The ROC curves indicated that plasma Linc00152 has high diagnostic accuracy for NSCLC, and the area under curve (AUC) for NSCLC versus healthy was 0.816 (95% CI: 0.757–0.875). Moreover, we found that the combination of Linc00152 and CEA could provide a more powerful diagnosis efficiency than Linc00152 or CEA alone (AUC = 0.881, 95% CI: 0.836–0.926).

Conclusions

Plasma Linc00152 could serve as a promising biomarker for diagnosing and monitoring NSCLC.

Plasma microRNA-based signatures to predict 3-year postoperative recurrence risk for stage II and III gastric cancer

Our aim was to identify plasma microRNA (miRNA)-based signatures to predict 3-year postoperative recurrence risk for patients with stage II and III gastric cancer (GC), so as to provide insights for individualized adjuvant therapy. Plasma miRNA expression was investigated in three phases, involving 407 patients recruited from three centers. ABI miRNA microarray and TaqMan Low Density Array were adopted in the discovery phase to identify potential miRNAs. Quantitative reverse-transcriptase polymerase chain reaction was used to assess the expression of selected miRNAs. Logistic regression models were constructed in the training set (n = 170) and validated in the validation set (n = 169). Receiver operating characteristic analyses, survival analyses and subgroup analyses were further used to assess the accuracy of the models. We identified a 7 miRNA classifier and 7miR + pathological factors index that provided high predictive accuracy of GC recurrence (area under the curve = 0.725 and 0.841 in the training set; and 0.627 and 0.771 in the validation set). High-risk patients defined by the signatures had significantly shorter disease-free survival and overall survival than low-risk patients. The 7 miRNA classifier is an independent prognostic factor, and could add predictive value to traditional prognostic factors. Subgroup analyses revealed the satisfactory performance persisted regardless of stage, and the two models both displayed high accuracy in stage IIA patients. In conclusion, identified microRNA signature may potentially provide some additional benefit for prediction of disease recurrence in patients with stage II and III GC.

MicroRNA-195 inhibits human gastric cancer by directly targeting basic fibroblast growth factor

PURPOSE

Gastric cancer (GC) is one of the fatal malignancies worldwide with high occurrences but poor outcomes. bFGF has been shown to play significant roles in GC. Yet, whether bFGF affects the development of GC is less studied.

METHODS

MicroRNA assays, real-time PCR, and western blot were conducted for expression analysis of miR-195-5p and basic fibroblast growth factor (bFGF). Luciferase activity was measured with mutated bFGF 3'-UTR sequence at the 3' end of the luciferase gene. Two GC cell lines, SNU-1 and KATO-3 overexpressing miR-195-5p and bFGF were subjected to wound healing assay and transwell invasion assay. Mouse GC xenograft model was established and subjected to tumor size analysis.

RESULTS

Expression levels of miR-195-5p and bFGF showed negative correlation in human GC tissues. MiR-195-5p directly targeted bFGF 3'-UTR as demonstrated by luciferase activity assay. MiR-195-5p, through downregulating bFGF, inhibited the migration and invasion of SNU-1 and KATO-3 cells, as well as tumorigenesis in a xenograft mouse model, which could be restored by re-introduction of bFGF.

CONCLUSIONS

MiR-195-5p inhibits tumorigenesis of GC through suppressing bFGF, which supports both miR-195-5p and bFGF as potential therapeutic targets in the treatment of GC.

MiRNA expression profiles reveal the involvement of miR-26a, miR-548l and miR-34a in hepatocellular carcinoma progression through regulation of ST3GAL5

MicroRNAs (miRNAs) have key roles in comprehensive physiological and pathological processes by targeting specific genes through translational repression. Identification of miRNAs related to metastasis enables us to obtain better insight into cancer development. In the current study, we investigated the miRNA expressional profiles in the highly invasive human hepatocellular carcinoma cell line MHCC97-H and MHCC97-L with lower metastatic potential using miRNA microarrays. By quantitative real-time PCR, we confirmed the results of miRNA experiments. Thirteen differentially expressed miRNAs were identified between MHCC97-H and MHCC97-L cells; and the same results were found in clinical samples. Using bioinformatic analysis and luciferase reporter assay, we found that ST3GAL5, a sialyltransferase gene, was the direct target of miR-26a, miR-548l and miR-34a. Engineered expression of miR-26a, miR-548l or miR-34a in MHCC97-H or MHCC97-L cells could significantly change their malignant behaviors and oncogenicity in in vitro and in vivo assays. Manipulated expression of ST3GAL5 also led to the alteration of the metastatic potential of MHCC97-H and MHCC97-L cells, in agreement with the effects of above three miRNAs. Altogether, our data indicate that the levels of these miRNAs may be used as biological markers for evaluating hepatocellular carcinoma progression. miR-26a, miR-548l and miR-34a, acting as tumor suppressors, may exert their effects by regulating ST3GAL5.

The role of extracellular vesicle microRNAs in cancer biology

microRNAs (miRNAs) constitute a large family of small, approximately 20-22 nucleotide non-coding RNAs that regulate the expression of target genes, mainly at the post-transcriptional level. Multiple studies report that miRNAs are involved in homeostatic maintenance and that aberrant expression of miRNAs is often observed in various types of diseases, including cancer. In cancer biology, miRNAs exert functional roles in tumor initiation, drug resistance, and metastasis. miRNAs are also secreted through small vesicles called exosomes, which are endosome-derived vesicles derived from various cell types including immune and tumor cells. In addition to cellular miRNAs (ce-miRNAs), secreted miRNAs (se-miRNAs) play important roles in cancer development and metastasis. Therefore, se-miRNAs in body fluids have been investigated as a promising biomarkers and therapeutic targets for cancer treatment. In this review, we summarize the current knowledge of miRNA functions in cancer development and discuss the potential clinical applications of se-miRNAs, e.g. as diagnostic markers and therapeutic targets.

Expression and prognostic value of microRNA-26a and microRNA-148a in gastric cancer

BACKGROUND AND AIM

In our previous study, we demonstrated that four microRNAs (miRNAs) (miR-26a, miR-142-3p, miR-148a, and miR-195) that were downregulated in both plasma and tumor tissues were confirmed to be promising non-invasive diagnostic biomarkers for gastric cancer (GC).

METHODS

We used the quantitative reverse transcription polymerase chain reaction to assess the expression levels of the four miRNAs from paraffin-embedded surgical specimens of GC patients. Kaplan-Meier curves and log-rank test were applied to predict the correlation between miRNAs and cumulative overall survival (OS) of patients with GC. Besides, we performed in vitro assays including cell proliferation, migration, invasion and colony formation, and apoptosis.

RESULTS

The median of miRNA expression in paraffin-embedded tissues were used as the cutoff value to classify patients into high or low expression groups. Down-regulation of miR-26a and miR-148a was significantly associated with shorter OS of GC patients either in the test set (miR-26a: P = 0.009; miR-148a: P = 0.005) or the validation set (miR-26a: P = 0.011; miR-148a: P = 0.024). When two sets were combined, Cox regression analysis demonstrated that both of miR-26a and miR-148a were independent prognostic factors for predicting OS of patients with GC (miR-26a: HR = 0.76, 95% CI = 0.61-0.94; miR-148a: HR = 0.73, 95% CI = 0.58-0.91). Furthermore, elevated expression of miR-26 significantly suppressed cell proliferation, migration, invasion and colony formation, and induced apoptosis of MGC-803 cells compared with negative control groups (P < 0.05).

CONCLUSION

These findings supported miR-26a and miR-148a could serve as potential prognostic biomarkers for GC.

Long non-coding RNA 00312 regulated by HOXA5 inhibits tumour proliferation and promotes apoptosis in Non-small cell lung cancer

Non‐small cell lung cancer (NSCLC) is the most prevalent type of lung cancer. The abnormal expression of many long non‐coding RNAs (lncRNAs) has been reported involved in the progression of various tumours, which can be used as diagnostic indicators or antitumour targets. Here, we found that the long non‐coding RNA 00312 was down‐regulated in paired NSCLC tissues and correlated with poor clinical outcome; decreased linc00312 expression in NSCLC was associated with larger and later stage tumours. Functional experiments showed that linc00312 could inhibit cell proliferation and promote apoptosis in vitro and in vivo. Furthermore, we found that HOXA5 could bind in the promoter of linc00312 and up‐regulated the expression of it. Moreover, linc00312 was down‐regulated in the plasma of NSCLC patients compared with that of healthy volunteers or other pulmonary diseases patients. Taken together, our findings indicated that linc00312 could be a novel diagnosis biomarker and a promising therapeutic target for NSCLC.

A proposed method for the relative quantification of levels of circulating microRNAs in the plasma of gastric cancer patients

Gastric cancer (GC) is the fifth most common type of malignancy and the third leading cause of cancer-associated mortality worldwide. It is necessary to identify novel methods aimed at improving the early diagnosis and treatment of GC. MicroRNA expression profiles in the plasma of patients with GC have demonstrated a potential use in the opportune diagnosis of this neoplasm. However, there are currently no standardized targets for use in the normalization of microRNA Cq values for different neoplasms. The present study tested two normalization approaches while analyzing plasma derived from patients with GC and non-atrophic gastritis. The first method utilized a panel of small nucleolar RNAs (snoRNAs) and a small nuclear RNA (snRNA) provided by a commercial array. The second normalization approach involved the use of hsa-miR-18a-5p and hsa-miR-29a-3p, which were identified by a stability analysis of the samples being tested. The results revealed that the snoRNAs and snRNA were not expressed in all samples tested. Only the stable microRNAs allowed a narrow distribution of the data and enabled the identification of specific downregulation of hsa-miR-200c-3p and hsa-miR-26b-5p in patients with GC. hsa-miR-200c-3p and hsa-miR-26b-5p have been previously linked to cancer, and a Kyoto Encyclopedia of Genes and Genomes analysis demonstrated that these microRNAs were associated with cell adhesion, cell cycle and cancer pathways.