Plasma microRNA profiles: identification of miR-744 as a novel diagnostic and prognostic biomarker in pancreatic cancer

Serum level of co-expressed hub miRNAs as diagnostic and prognostic biomarkers for pancreatic ductal adenocarcinoma

Background: Sensitive and specific non-invasive biomarkers are urgently needed in order to improve the survival of patients with pancreatic ductal adenocarcinoma (PDAC), which is the fourth leading cause of cancer-related death. We aim to identify serum hub miRNAs as potential diagnostic and prognostic biomarkers for PDAC.

Methods: A total of 2578 serum miRNA expression data from 88 PDAC patients and 19 healthy subjects were downloaded from the Gene Expression Omnibus database. Weighted gene co-expression network analysis (WGCNA) was constructed and significant modules were extracted from the network by WGCNA R package. Network modules and hub miRNAs closely related to PDAC were identified. The prognostic value of hub miRNAs was assessed by Kaplan-Meier overall survival analysis.

Results: Two modules strongly associated with PDAC were identified by WGCNA, which were labeled as turquoise and brown respectively. Within each module, twenty hub miRNAs were found. At the functional level, turquoise module was mainly associated with tumorigenesis pathways such as P53 and WNT signaling pathway, while the brown module was mostly related to the pathways of cancer such as RNA transport and MAPK signaling pathway. Utilizing overall survival analyses, five “real” miRNAs were able to stratify PDAC patients into low-risk and high-risk groups.

Conclusions: The association of specific Hub miRNAs with the development of pancreatic cancer was established by WGCNA analysis. Five miRNAs (mir-16-2-3p, mir-890, mir-3201, mir-602, and mir-877) were identified as potential diagnostic and prognostic biomarkers for PDAC.

The Significance of Liquid Biopsy in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer. The 5-year survival rate for PDAC remains low because it is always diagnosed at an advanced stage and it is resistant to therapy. A biomarker, which could detect asymptomatic premalignant or early malignant tumors and predict the response to treatment, will benefit patients with PDAC. However, traditional biopsy has its limitations. There is an urgent need for a tumor biomarker that could easily and repeatedly sample and monitor, in real time, the progress of tumor development. Liquid biopsy could be a tool to assess potential biomarkers. In this review, we focused on the latest discoveries and advancements of liquid biopsy technology in pancreatic cancer research and demonstrated how this technology is being used in clinical applications.

Clinical utilization of serum- or plasma-based miRNAs as early detection biomarkers for pancreatic cancer: A meta-analysis up to now

BACKGROUND

Pancreatic cancer (PC) is a lethal disease, however current screening methods unable to achieve early diagnosis. Blood-based microRNAs (miRNAs) are promising molecular biomarkers for detecting PC. This meta-analysis summaries studies identifying serum- or plasma-based miRNAs dysregulated in PC patients compared to non-PC cases to evaluate their diagnostic accuracy for characterizing PC.

METHODS

A systematically reviews and meta-analysis of published studies was conducted to compare the serum or plasma miRNAs expressions between PC patients and non-PC cases. Summary estimates for sensitivity, specificity, along with other measures of accuracy of miRNAs in the diagnosis of PC were pooled using the random-effects model. I and Q tests were used to assess the heterogeneity of included studies. The Spearman test was used to analyze the threshold effect.

RESULTS

Twenty-seven eligible studies were identified after electronic search and literature selection. For single miRNA dysregulation, 32 miRNAs were found to be upregulated in PC patients, and 5 miRNAs were downregulated. Four studies identified a 2-miRNA panel, and 10 studies identified a panel consisting of 3 or more miRNAs which were used to detect PC patients. Additionally, 8 studies combined miRNA panels and carbohydrate antigen 19-9 (CA 19-9) to diagnose PC. The pooled sensitivities for these 4 groups were 0.77 to 0.85, and specificities were 0.70 to 0.87. The highest area under the curve (AUC), 0.9308, was identified using 2 miRNA panels with sensitivity and specificity of 0.79 (0.74-0.83) and 0.85 (0.81-0.89), respectively. There was great heterogeneity of these 4 miRNA groups. Results of Spearman test revealed that there existed a threshold effect on single miRNA group (r=-0.437, P=.001), and none of the other groups (P all>.05).

CONCLUSIONS

Serum- or plasma-based miRNAs are capable of distinguishing PC from non-PC with relatively high sensitivity and specificity. In future, miRNAs may be used as promising diagnostic biomarkers for detection of PC.

Glycoprotein biomarkers for the detection of pancreatic ductal adenocarcinoma

Pancreatic cancer (PaC) shows a clear tendency to increase in the next years and therefore represents an important health and social challenge. Currently, there is an important need to find biomarkers for PaC early detection because the existing ones are not useful for that purpose. Recent studies have indicated that there is a large window of time for PaC early detection, which opens the possibility to find early biomarkers that could greatly improve the dismal prognosis of this tumor. The present manuscript reviews the state of the art of the existing PaC biomarkers. It focuses on the anomalous glycosylation process and its role in PaC. Glycan structures of glycoconjugates such as glycoproteins are modified in tumors and these modifications can be detected in biological fluids of the cancer patients. Several studies have found serum glycoproteins with altered glycan chains in PaC patients, but they have not shown enough specificity for PaC. To find more specific cancer glycoproteins we propose to analyze the glycan moieties of a battery of glycoproteins that have been reported to increase in PaC tissues and that can also be found in serum. The combination of these new candidate glycoproteins with their aberrant glycosylation together with the existing biomarkers could result in a panel, which would expect to give better results as a new tool for early diagnosis of PaC and to monitor the disease.

MiR-744-5p inducing cell death by directly targeting HNRNPC and NFIX in ovarian cancer cells

MicroRNAs (miRNAs) play an important role in the regulation of gene expression. The binding to target messenger RNAs (mRNAs) results in mRNA cleavage or inhibition of the translational machinery leading to decreased protein levels. Various signalling pathways, including apoptosis are modulated by miRNAs. Here, we investigated the role of miR-744-5p in apoptosis signalling in ovarian cancer cell lines. MiR-744-5p expression was reduced in the cancer cell lines independent of the host gene MAP2K4. Overexpression of miR-744-5p activated the intrinsic apoptotic pathway in SKOV3, OVCAR3 and Cisplatin resistant (A2780-cis) and non-resistant A2780 cells leading to cell death. Notably, miR-744-5p overexpression together with Carboplatin treatment led to at least additive pro-apoptotic effects. Investigation of the apoptotic signalling pathways mediated by miR-744-5p revealed that its elevated expression directly downregulated mRNA and protein expression of nuclear factor I X (NFIX) and heterogeneous nuclear ribonucleoprotein C (HNRNPC). HNRNPC caused diminished miR-21 expression and AKT phosphorylation, while NFIX decreased Bcl2 levels, leading to the detected pro-apoptotic effects. Finally, Kaplan-Meier-Plots showed a prolonged median disease-free survival in ovarian serous cystadenocarcinoma patients with high miR-744 expression.

Blood-Derived microRNAs for Pancreatic Cancer Diagnosis: A Narrative Review and Meta-Analysis

microRNAs (miRNAs) have been reported to be aberrantly expressed in patients with pancreatic cancer. In present review we explored the biological roles of miRNAs in pancreatic cancer and their clinical value in diagnosis. In the systematic review, the potential value of miRNAs as biomarkers was investigated by reviewing the altered miRNA profiles reported in pancreatic cancer patients in 356 included studies. In the subsequent meta-analysis, we included 17 studies in early diagnosis of pancreatic cancer with a panel of altered miRNAs. The following results were obtained: pooled sensitivity of 0.88 (95% confidence interval [CI] 0.83–0.92), pooled specificity of 0.83 (95%CI 0.77–0.88), diagnostic odds ratio of 27 (95%CI 14–53), and area under the receiver operating characteristic curve of 0.90 (95%CI 0.88–0.93). To further explore the value of a single miRNA, the diagnostic value of miR-21 in PA was also demonstrated by the pooled sensitivity (0.90, 95% CI: 0.82–0.94), specificity (0.72, 95% CI: 0.57-0.83) as well as AUC (0.91 (95%CI 0.88–0.93). In conclusion, our findings suggest that aberrant miRNA expression in blood play an essential role in pancreatic cancer, and meta-analysis revealed blood-derived miRNAs as probable biomarkers for early diagnosis of pancreatic cancer.

Plasma microRNA profiles: identification of miR-23a as a novel biomarker for chemoresistance in esophageal squamous cell carcinoma

BACKGROUND

This study aims to explore novel microRNAs in plasma for predicting chemoresistance in preoperative chemotherapy of patients with esophageal squamous cell carcinoma (ESCC) using a microRNA array-based approach.

RESULTS

(1) Four candidate microRNAs (miR-223, 103a, 23b and 23a), which were highly expressed in the pretreatment plasma of patients with a low histopathologic response, were selected. (2) In a large-scale validation analysis by quantitative RT–PCR, plasma levels of miR-223, miR-23b and miR-23a were significantly higher in patients with a low histopathologic response than in those with a high histopathologic response (p = 0.0345, p = 0.0125 and p = 0.0114). (3) Of all candidate microRNAs, miR-23a expression of pretreatment ESCC tumor tissues was significantly higher in ESCC patients with a low histopathologic response than in those with a high histopathologic response (p = 0.0278). (4) After overexpressing each candidate in ESCC cells, miR-23a induced significant chemoresistance to both 5-fluorouracil and cisplatin, and miR-223 to cisplatin in vitro. (5) A high level of plasma miR-23a, which tended to correlate with lymphatic invasion (p = 0.0808) and deep depth of invasion (p = 0.0658), was an independent risk factor for chemoresistance in ESCC (p = 0.0222; odds ratio: 12.4; range 1.46–105).

MATERIALS AND METHODS

We used the Toray^® 3D-Gene microRNA array-based approach to compare plasma microRNA levels between patients with a high or a low histopathologic response to chemotherapy. All patients underwent a preoperative chemotherapy regimen with cisplatin plus 5-fluorouracil.

CONCLUSIONS

Plasma miR-23a might be a useful biomarker for predicting chemoresistance in ESCC patients.

Genome-wide Discovery and Identification of a Novel miRNA Signature for Recurrence Prediction in Stage II and III Colorectal Cancer

Purpose: The current tumor-node-metastasis (TNM) staging system is inadequate at identifying patients with high-risk colorectal cancer. Using a systematic and comprehensive biomarker discovery and validation approach, we aimed to identify an miRNA recurrence classifier (MRC) that can improve upon the current TNM staging as well as is superior to currently offered molecular assays.Experimental Design: Three independent genome-wide miRNA expression profiling datasets were used for biomarker discovery (N = 158) and in silico validation (N = 109 and N = 40) to identify an miRNA signature for predicting tumor recurrence in patients with colorectal cancer. Subsequently, this signature was analytically trained and validated in retrospectively collected independent patient cohorts of fresh-frozen (N = 127, cohort 1) and formalin-fixed paraffin-embedded (FFPE; N = 165, cohort 2 and N = 139, cohort 3) specimens.Results: We identified an 8-miRNA signature that significantly predicted recurrence-free interval (RFI) in the discovery (P = 0.002) and two independent publicly available datasets (P = 0.00006 and P = 0.002). The RT-PCR-based validation in independent clinical cohorts revealed that MRC-derived high-risk patients succumb to significantly poor RFI in patients with stage II and III colorectal cancer [cohort 1: hazard ratio (HR), 3.44 (1.56-7.45), P = 0.001; cohort 2: HR, 6.15 (3.33-11.35), P = 0.001; and cohort 3: HR, 4.23 (2.26-7.92), P = 0.0003]. In multivariate analyses, MRC emerged as an independent predictor of tumor recurrence and achieved superior predictive accuracy over the currently available molecular assays. The RT-PCR-based MRC risk score = (-0.1218 × miR-744) + (-3.7142 × miR-429) + (-2.2051 × miR-362) + (3.0564 × miR-200b) + (2.4997 × miR-191) + (-0.0065 × miR-30c2) + (2.2224 × miR-30b) + (-1.1162 × miR-33a).Conclusions: This novel MRC is superior to currently used clinicopathologic features, as well as National Comprehensive Cancer Network (NCCN) criteria, and works regardless of adjuvant chemotherapy status in identifying patients with high-risk stage II and III colorectal cancer. This can be readily deployed in clinical practice with FFPE specimens for decision-making pending further model testing and validation. Clin Cancer Res; 24(16); 3867-77. ©2018 AACRSee related commentary by Rodriguez et al., p. 3787.

MicroRNA-744 Inhibits Cellular Proliferation and Invasion of Colorectal Cancer by Directly Targeting Oncogene Notch1

Accumulated studies have strongly implicated aberrantly expressed microRNAs (miRNAs) in carcinogenesis and cancer progression of various cancers, including colorectal cancer (CRC). Hence, a comprehensive study of miRNAs and their association with CRC may be a promising therapeutic method for patients with this malignancy. MicroRNA-744 (miR-744) is abnormally expressed in several types of human cancer. Thus far, little is known about the expression, biological roles, and exact mechanisms of miR-744 in CRC. Thus, the present study measured the expression level of miR-744 and investigated its roles and associated molecular mechanisms in CRC. This study demonstrated that miR-744 expression was significantly underexpressed in CRC tissues and cell lines. Low miR-744 expression was positively associated with lymphatic metastasis and TNM stage. Functional experiments revealed that miR-744 overexpression obviously inhibited the proliferation and invasion of CRC cells. Furthermore, Notch1 was identified as a direct target of miR-744 in CRC. Moreover, the inhibition of Notch1 phenocopied the inhibitory effects of miR-744 overexpression on CRC cells. Restored Notch1 expression markedly rescued the tumor-suppressive effects of miR-744 overexpression on CRC cells. Overall, miR-744 exhibits an essential role in CRC progression, and the miR-744/Notch1 axis may provide novel insights into future treatments for patients with CRC.

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.

Circulating microRNA profiles in plasma: identification of miR-224 as a novel diagnostic biomarker in hepatocellular carcinoma independent of hepatic function

Aims

This study was designed to identify novel microRNAs (miRNAs) in plasma for detecting and monitoring hepatocellular carcinoma (HCC), independent of hepatic function and background liver diseases with different etiologies.

Results

(1) Four oncogenic miRNAs (miR-151, 155, 191 and 224) with high expression in HCC tissues were selected as candidates. (2) Quantitative RT-PCR using plasma samples from 107 HCC patients and 75 healthy volunteers revealed a significantly higher level of plasma miR-224 in HCC patients than in healthy volunteers according to a small-scale analysis (P < 0.0001), two independent large-scale cohort analysis (P < 0.0001, AUC 0.908). (3) miR-224 expression was significantly higher in HCC tissues and HCC cell lines than in normal hepatic tissues and fibroblasts, respectively. (P = 0.0011, 0.0150) (4) Plasma miR-224 reflected tumor dynamics; preoperative plasma levels of miR-224 were significantly reduced in postoperative samples (P = 0.0058), and plasma miR-224 levels were significantly correlated with paired miR-224 levels in HCC tissues (P = 0.0005). (5) Furthermore, plasma miR-224 levels significantly discriminated HCC patients from patients with chronic liver disease (P = 0.0008). A high plasma miR-224 level was significantly correlated with larger tumor size (P = 0.0005) and recurrences (P = 0.0027). The plasma miR-224 level could accurately detect small tumors less than 18 mm preoperatively.

Methods

We performed a systematic review of the NCBI database and selected candidate miRNAs reported as highly expressed in HCC tissue.

Conclusions

Plasma miR-224 may be a sensitive biomarker for screening HCC and monitoring tumor dynamics.

MicroRNA regulatory networks reflective of polyhexamethylene guanidine phosphate-induced fibrosis in A549 human alveolar adenocarcinoma cells

Polyhexamethylene guanidine phosphate (PHMG-phosphate), an active component of humidifier disinfectant, is suspected to be a major cause of pulmonary fibrosis. Fibrosis, induced by recurrent epithelial damage, is significantly affected by epigenetic regulation, including microRNAs (miRNAs). The aim of this study was to investigate the fibrogenic mechanisms of PHMG-phosphate through the profiling of miRNAs and their target genes. A549 cells were treated with 0.75 μg/mL PHMG-phosphate for 24 and 48 h and miRNA microarray expression analysis was conducted. The putative mRNA targets of the miRNAs were identified and subjected to Gene Ontology analysis. After exposure to PHMG-phosphate for 24 and 48 h, 46 and 33 miRNAs, respectively, showed a significant change in expression over 1.5-fold compared with the control. The integrated analysis of miRNA and mRNA microarray results revealed the putative targets that were prominently enriched were associated with the epithelial-mesenchymal transition (EMT), cell cycle changes, and apoptosis. The dose-dependent induction of EMT by PHMG-phosphate exposure was confirmed by western blot. We identified 13 putative EMT-related targets that may play a role in PHMG-phosphate-induced fibrosis according to the Comparative Toxicogenomic Database. Our findings contribute to the comprehension of the fibrogenic mechanism of PHMG-phosphate and will aid further study on PHMG-phosphate-induced toxicity.

Roles of GSK-3 and microRNAs on epithelial mesenchymal transition and cancer stem cells

Various signaling pathways exert critical roles in the epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs). The Wnt/beta-catenin, PI3K/PTEN/Akt/mTORC, Ras/Raf/MEK/ERK, hedgehog (Hh), Notch and TP53 pathways elicit essential regulatory influences on cancer initiation, EMT and progression. A common kinase involved in all these pathways is moon-lighting kinase glycogen synthase kinase-3 (GSK-3). These pathways are also regulated by micro-RNAs (miRs). TP53 and components of these pathways can regulate the expression of miRs. Targeting members of these pathways may improve cancer therapy in those malignancies that display their abnormal regulation. This review will discuss the interactions of the multi-functional GSK-3 enzyme in the Wnt/beta-catenin, PI3K/PTEN/Akt/mTORC, Ras/Raf/MEK/ERK, Hh, Notch and TP53 pathways. The regulation of these pathways by miRs and their effects on CSC generation, EMT, invasion and metastasis will be discussed.

Low plasma levels of miR-101 are associated with tumor progression in gastric cancer

Background

Several studies have identified the decreased expression of the tumor suppressor miR-101 in various cancers. In this study, we tested miR-101 as a potential therapeutic target and novel plasma biomarker for gastric cancer (GC).

Results

The miR-101 expression level was significantly lower in GC tissues (P = 0.0038) and GC cell lines (P = 0.0238) than in normal gastric mucosa. Both exosomal and plasma miR-101 were significantly downregulated in GC patients compared with healthy volunteers (P = 0.0281 and P < 0.0001, respectively). Low miR-101 plasma level was significantly associated with advanced T factor, advanced disease stage, and peritoneal metastasis and predicted poor prognosis in GC patients (P = 0.0368; hazard ratio, 3.079; 95% confidence interval: 1.06–11.08). Overexpression of miR-101 in GC cells induced apoptosis by inhibiting MCL1 and suppressed cell migration and invasion by regulating ZEB1.

Conclusions

Depletion of the tumor suppressor miRNA-101 in plasma is related to tumor progression and poor outcomes. Low plasma miR-101 may be a biomarker for GC, and its restoration might be a novel anticancer treatment strategy.

MicroRNA-744 promotes prostate cancer progression through aberrantly activating Wnt/β-catenin signaling

Accumulated evidence indicate that miR-744 functions as either tumor suppressor or oncogene in the progression of a variety of tumors, with a tumor type-specific way. However, little is known about how miR-744 impacts on the tumorigenesis of human prostate cancer. In this study, employing the analyses of microarray, qRT-PCR and re-analysis of MSKCC data, we found that CRPC tissues expressed much more miR-744 than ADPC tissues did, and the expression level of miR-744 was inversely associated with survival of CRPC patients. In vitro studies revealed that miR-744 promotes PCa cells proliferation, enhances migration, invasion; in vivo results demonstrated that silencing of miR-744 mediated by shRNA dramatically reduces PCa xenograft tumor growth. Importantly, through human gene expression array, pathway enrichment analysis and Western blot, we identified that miR-744 dramatically activated Wnt/β-catenin pathway by targeting multiple negative regulators of Wnt/β-catenin signaling, including SFRP1, GSK3β, TLE3 and NKD1. At molecular level, we further defined that NKD1 is a major functional target of miR-744. Our findings indicate that miR-744 acts as one of oncogenic factor in the progression of CRPC by recruiting a mechanism of aberrant activation of Wnt/β-catenin signaling.

Prognostic value of microRNA expression levels in pancreatic adenocarcinoma: a review of the literature

Background

Clinical and pathologic markers of prognosis and patterns of failure help guide clinicians in selecting patients for adjuvant therapy after surgical resection for pancreatic adenocarcinoma (PDAC). Recent studies have reported the prognostic utility of microRNA profiling in numerous malignancies. Here, we review and summarize the current literature regarding associations between microRNA expression and overall survival in PDAC patients.

Materials and Methods

We conducted a systematic search in the PubMed database to identify all primary research studies reporting prognostic associations between tumor and/or serum microRNA expression and overall survival in PDAC patients. Eligible articles were reviewed by the authors and relevant findings are summarized below.

Results

We found 53 publications that fit our search criteria. In total, 23 up-regulated and 49 down-regulated miRNAs have been associated with worse overall survival. MiR-21 is the most commonly reported miRNA, appearing in 19 publications, all of which report aberrant over-expression and association with shorter survival in PDAC. Other miRNAs that appear in multiple publications include miR-10b, −21, −34a, −155, −196a, −198, −200c, −203, −210, −218, −222, and −328. We summarize the preclinical and clinical data implicating these miRNAs in various molecular signaling pathways and cellular functions.

Conclusions

There is growing evidence that miRNA expression profiles have the potential to provide tumor-specific prognostic information to assist clinicians in more appropriately selecting patients for adjuvant therapy. These molecules are often aberrantly expressed and exhibit oncogenic and/or tumor suppressor functions in PDAC. Additional efforts to develop prognostic and predictive molecular signatures, and further elucidate miRNA mechanisms of action, are warranted.

Clinical Relevance of microRNA Expressions in Breast Cancer Validated Using the Cancer Genome Atlas (TCGA)

BACKGROUND

MicroRNAs (miRNAs) play a critical role in the carcinogenesis and progression of breast cancer. MiRNA-205 has tumor suppressive properties, whereas miRNA-18a has both oncogenic and tumor suppressive roles. MiRNA-744's role in breast cancer is unknown but is tumor-suppressive in vitro. We hypothesize that high expression of all three miRNAs is associated with a better survival based on their known functions in breast cancer.

METHODS

All data was obtained from the Cancer Genome Atlas (TCGA). Expression patterns of miRNA-18a, miRNA-205, and miRNA-744 were retrieved from the Genomic Data Commons (GDC) data portal for analyses. After miRNA-specific thresholds were derived and used to group the patients into a high- or low-expression group, survival data was calculated by using the Cox proportional hazard model. Further subanalyses separating the patients based on receptor status and AJCC 7th edition TNM staging were similarly compared.

RESULTS

In total, 1,052 of 1,097 samples logged in TCGA had clinical data and miRNA-sequence datasets on the miRNAs of interest. High expression of miRNA-18a (p = 0.079), miRNA-205 (p = 0.034), and miRNA-744 (p = 0.0135) was associated with better survival. On subanalysis, estrogen receptor (ER)-positive, progesterone receptor (PR)-positive, and lymph node-negative disease had a statistically significant survival advantage with miRNA-18a, miRNA-205, and miRNA-744 high expression.

CONCLUSIONS

By utilizing a big dataset (TCGA) with sufficient statistical power, we found that high expression of miRNA-18a, miRNA-205, and miRNA-744 in the breast tumor samples were all associated with better overall survival in ER/PR-positive, lymph node-negative disease supporting their role as a tumor suppressor in breast cancer.

Depleted tumor suppressor miR-107 in plasma relates to tumor progression and is a novel therapeutic target in pancreatic cancer

This study explored decreased tumor suppressor microRNA (miRNA) plasma levels in pancreatic cancer (PCa) patients to clarify their potential as novel biomarkers and therapeutic targets. We used the microRNA array-based approach to select candidates by comparing plasma levels between PCa patients and healthy volunteers. Six down-regulated miRNAs (miR-107, miR-126, miR-451, miR-145, miR-491-5p, and miR-146b-5p) were selected. Small- and large-scale analyses using samples from 100 PCa patients and 80 healthy volunteers revealed that miR-107 was the most down-regulated miRNA in PCa patients compared with healthy volunteers (P < 0.0001; area under the receiver-operating characteristic curve, 0.851). A low miR-107 plasma level was significantly associated with advanced T stage, N stage, and liver metastasis and was an independent factor predicting poor prognosis in PCa patients (P = 0.0424; hazard ratio, 2.95). miR-107 overexpression in PCa cells induced G1/S arrest with the production of p21 and inhibited cell proliferation through the transcriptional regulation of Notch2. In vivo, the restoration and maintenance of the miR-107 plasma level significantly inhibited tumor progression in mice. Depletion of the tumor suppressor miR-107 in plasma relates to tumor progression and poor outcomes. The restoration of the plasma miR-107 level might be a novel anticancer treatment strategy for PCa.

消化系肿瘤循环微小RNA研究进展

微小RNA(microRNA, miRNA)是一类内源性的、21-25个碱基长度的小分子非编码RNA, 在转录后水平调节靶基因mRNA表达, 并在多种肿瘤的发生和发展中过程中发挥重要的促癌或抑癌作用. 不同肿瘤类型有着各自特异性miRNA表达谱. 近来研究发现游离的miRNA可稳定地存在于血清和血浆中, 并作为一个潜在的非侵入性生物标志物, 该研究领域已成为当前临床研究的热点. 循环中的miRNA作为肿瘤相关生物标志物, 不仅可以反应早期肿瘤的存在, 而且可以检测肿瘤的发展、复发情况以及对药物敏感性. 这种"液体活检"的方法可提供非侵袭性的和持续表达的生物标志物, 并且为肿瘤患者个体化治疗提供一种新的策略. 本文综述了近几年循环miRNA在实体瘤尤其是消化系肿瘤的研究进展, 并探讨了其作为消化系恶性肿瘤潜在的诊断标志物或治疗靶点的发展前景.

Identification of miR‑124a as a novel diagnostic and prognostic biomarker in non‑small cell lung cancer for chemotherapy

Previous studies have suggested that dysregulation of microRNA (miR) −124a is associated with various types of human cancer. However, there are few studies reporting the level of miR-124a expression in non-small cell lung cancer (NSCLC). The present study investigated the association between miR-124a and NSCLC by analyzing the differential expression of miR-124a in NSCLC using the GEO database, as well as subsequently performing reverse transcription-quantitative polymerase chain reaction analysis on 160 NSCLC biopsies, 32 of which were paired with adjacent normal tissues. The results indicated that mir-124a expression levels were decreased in NSCLC tumor biopsies compared with adjacent normal tissues. The overall survival (OS) in patients with a high expression of miR-124a was prolonged relative to patients with low expression of miR-124a. The expression levels of miR-124a were associated with clinical characteristics, including lymph-node metastasis, tumor differentiation, tumor node metastasis (TNM) stage and diameter. Frequently, lymph-node metastasis, TNM stage, diameter and lack of chemotherapy have been associated with a worse prognosis in patients. In addition, the present study identified that high expression of miR-124awith chemotherapy may increase OS. In conclusion, the current study demonstrated that miR-124a was downregulated in NSCLC, and miR-124a was a potential prognostic tumor biomarker response to chemotherapy.

MicroRNA-221-3p is up-regulated and serves as a potential biomarker in pancreatic cancer

It has been demonstrated that circulating MicroRNAs (miRNAs) could be potential biomarkers for cancer diagnosis and prognosis. For pancreatic cancer (PCa), little is known about miR-221-3p biological function or its prognostic value. In the current study, we profiled miR-221-3p expression in PCa cell lines. Compared with normal pancreases ductal epithelial cells, miR-221-3p is up-regulated in all PCa cell lines analysed. In SW1990 cells, overexpression of miR-221-3p increased cell proliferation and inhibited apoptosis, while inhibition of miR-221-3p decreased cell growth rate and promoted apoptosis. Compared with adjacent non-tumour tissues, miR-221-3p was up-regulated in all 21 PCa tissues. Expression level of miR-221-3p was investigated in plasma and statistical analyses showed that circulating miR-221-3p expression level was correlated with distant metastasis and TNM stages. The receiver-operating characteristic (ROC) curves and the area under the ROC curve (AUC) suggested that the diagnostic efficacy for distant metastasis of miR-221-3p is better than CA19-9 (AUC: 0.689 vs. 0.587). To summary, we found miR-221-3p could promote cell proliferation and inhibit apoptosis in PCa cells and circulating miR-221-3p could serve as a biomarker for PCa.

MiR-143 Targeting TAK1 Attenuates Pancreatic Ductal Adenocarcinoma Progression via MAPK and NF-κB Pathway In Vitro

BACKGROUND

Transforming growth factor (TGF)-β-activated kinase 1 (TAK1) is one of the major regulators of inflammation-induced cancer cell growth and progression. MiR-143 dysregulation is a common event in a variety of human diseases including pancreatic ductal adenocarcinoma (PDA).

AIMS

To identify the interaction between TAK1 and miR-143 in PDA.

METHODS

Data mining of TAK1 expression in PDA patient gene profiling was conducted. QRT-PCR and western blot were performed to detect the expression of TAK1 in PDA tissues and cell lines. Ectopic miR-143 and TAK1 were introduced to PDA cells. Cell growth, apoptosis and migration were examined. Xenograft models were used to examine the function of TAK1 in vivo. Western blot and luciferase assay were carried out to investigate the direct target of miR-143.

RESULTS

PDA patient gene profiling data (GSE15471 and GSE16515) showed that TAK1 mRNA was aberrantly up-regulated in PDA tissues. TAK1 protein levels were overexpressed in PDA tissues and cell lines. Overexpression of TAK1 was strongly associated with positive lymph node metastasis. Inhibition of TAK1 suppressed cell growth, migration, and induced cell apoptosis in vitro and in vivo. Further studies demonstrated that TAK1 was a direct target gene of miR-143. MiR-143 also inhibited PDA cells proliferation and migration, induced apoptosis and G₁/S arrest. Moreover, TAK1 depletion inactivated MAPK and NF-κB pathway, mimicking the function of miR-143.

CONCLUSIONS

The study highlights that miR-143 acts as a tumor suppressor in PDA through directly targeting TAK1, and their functional regulation may provide potential therapeutic strategies in clinics.

Identification of candidate miRNA biomarkers for pancreatic ductal adenocarcinoma by weighted gene co-expression network analysis

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a dismal prognosis which is, among others, due to a lack of suitable biomarkers and therapeutic targets. Previously, basic gene expression analysis methods have been used for their identification, but recently new algorithms have been developed allowing more comprehensive data analyses. Among them, weighted gene co-expression network analysis (WGCNA) has already been applied to several cancer types with promising results.

METHODS

We applied WGCNA to miRNA expression data from PDAC patients. Specifically, we processed microarray-based expression data of 2555 miRNAs in serum from 100 PDAC patients and 150 healthy subjects. We identified network modules of co-expressed miRNAs in the healthy subject dataset and verified their preservation in the PDAC dataset. In the non-preserved modules, we selected key miRNAs and carried out functional enrichment analyses of their experimentally known target genes. Finally, we tested their prognostic significance using overall survival analyses.

RESULTS

Through WGCNA we identified several miRNAs that discriminate healthy subjects from PDAC patients and that, therefore, may play critical roles in PDAC development. At a functional level, we found that they regulate p53, FoxO and ErbB associated cellular signalling pathways, as well as cell cycle progression and various genes known to be involved in PDAC development. Some miRNAs were also found to serve as novel prognostic biomarkers, whereas others have previously already been proposed as such, thereby validating the WGCNA approach. In addition, we found that these novel data may explain at least some of our previous PDAC gene expression analysis results.

CONCLUSIONS

We identified several miRNAs critical for PDAC development using WGCNA. These miRNAs may serve as biomarkers for PDAC diagnosis/prognosis and patient stratification, and as putative novel therapeutic targets.

[The microRNAs as biomarkers: What prospects?]

MicroRNAs are nucleic acids of about twenty nucleotides that regulate about a third of the genome at the post-transcriptional level. Thanks to their different forms of transport, microRNAs are stable and can be detected in biological fluids such as blood, urine, cerebrospinal fluid, or saliva. In addition, the profile of circulating microRNAs is a specific part of the cells in which it is secreted and is modified according to the physiological or pathological conditions of these cells. MicroRNAs therefore appear as biomarkers of interest for many diseases. However, these applications face several challenges because there are currently considerable differences between the sample processing procedures, assay methods, and especially the result standardization strategies. This literature review aims to take stock of the current use of microRNAs as biomarkers mainly in biological fluids and address the perspectives that emerge from the fact that their vesicular circulating forms could be used to assess the state of the cells and the tissues that produce them.

Noncoding RNAs as novel biomarkers in pancreatic cancer: what do we know?

Pancreatic cancer is an aggressive cancer of the digestive system, which is becoming a serious health problem worldwide. Overall survival for patients with pancreatic cancer is poor, mainly due to a lack of biomarkers to enable early diagnosis and a lack of prognostic markers that can inform decision-making, facilitating personalized treatment and an optimal clinical outcome. ncRNAs play an important role in pancreatic carcinogenesis. Here we review the literature on the role of ncRNAs as biomarkers in pancreatic cancer. We focus on the significance of ncRNAs as markers for early diagnosis, as prognostic biomarkers able to inform clinical management and as targets for novel therapeutics for patients with pancreatic cancer.

The small heat shock protein αA-crystallin negatively regulates pancreatic tumorigenesis

Our recent study has shown that αA-crystallin appears to act as a tumor suppressor in pancreas. Here, we analyzed expression patterns of αA-crystallin in the pancreatic tumor tissue and the neighbor normal tissue from 74 pancreatic cancer patients and also pancreatic cancer cell lines. Immunocytochemistry revealed that αA-crystallin was highly expressed in the normal tissue from 56 patients, but barely detectable in the pancreatic tumor tissue. Moreover, a low level of αA-crystallin predicts poor prognosis for patients with pancreatic duct adenocarcinoma (PDAC). In the 12 pancreatic cell lines analyzed, except for Capan-1 and Miapaca-2 where the level of αA-crystallin was about 80% and 65% of that in the control cell line, HPNE, the remaining pancreatic cancer cells have much lower αA-crystallin levels. Overexpression of αA-crystallin in MiaPaca-1 cells lacking endogenous αA-crystallin significantly decreased its tumorigenicity ability as shown in the colony formation and wound healing assays. In contrast, knockdown of αA-crystallin in the Capan-1 cells significantly increased its tumorigenicity ability as demonstrated in the above assays. Together, our results further demonstrate that αA-crystallin negatively regulates pancreatic tumorigenesis and appears to be a prognosis biomarker for PDAC.

Circulating MicroRNAs: A Next-Generation Clinical Biomarker for Digestive System Cancers

MicroRNAs (miRNAs) are short noncoding RNAs that post-transcriptionally regulate gene expression and play important roles in various physiological and developmental processes such as oncogenic or tumor suppressive regulators. Specific miRNA expression signatures have been identified in a number of human cancers. Cell-free miRNAs have recently been stably detected in plasma and serum (circulating miRNAs), and their presence in blood has attracted the attention of researchers due to their potential as non-invasive biomarkers. Circulating miRNAs have emerged as tumor-associated biomarkers that reflect not only the existence of early-stage tumors, but also the dynamics and status of advanced stage tumors, tumor recurrence, and drug sensitivities. This methodology for liquid biopsy may provide non-invasive and reproductive biomarkers and individualized therapeutic strategies for cancer patients. We herein review the current phase of biological and clinical research on the circulating miRNAs of solid cancers, particularly digestive tract cancers, and discuss future perspectives. The present review may be beneficial for future research on miRNAs used to detect various cancers.

Circulating microRNAs in cancer: Hope or hype?

Circulating miRNAs are a novel class of stable, minimally invasive disease biomarkers that are considered to be valuable in diagnosis, prognosis and treatment response monitoring. Unlike intracellular miRNAs, circulating miRNAs are released from their producer cells and, based on their targeted functions, they may shuttle in and out of circulation. Their discovery has opened up new avenues for clinical realms and led to a quest for targeted biomarkers. Subsequently, as more cell-free miRNAs are being discovered, their expression is expected to provide precise information regarding disease progression and treatment outcomes, thereby fostering personalized therapeutic strategies. The significance of circulating miRNAs capitalizes on the fact that they are highly stable in body fluids and their expression levels can be detected by common techniques such as qPCR and microarray. However, discrepancies have started to emerge in terms of their reliability and their response under physiological and pathological conditions. Functional studies are still pending, which may determine whether circulating miRNAs play a role as a central component or just as an auxiliary tuner. Also, the distinct clinical signatures that they display have never been subjected to an extensive critical review and experimental validation. As a consequence, the applicability of circulating miRNAs remains a matter of deliberation, despite many intriguing perspectives about their competency. In this review, we highlight some ambiguous issues with the application of circulating miRNAs, which may warrant an immediate consideration. We propose that the circulating miRNA domain needs to be reevaluated to authenticate their specific role and to probe whether they actually carry any clinical weightage.

Liquid biopsy in patients with pancreatic cancer: Circulating tumor cells and cell-free nucleic acids

Despite recent advances in surgical techniques and perioperative management, the prognosis of pancreatic cancer (PCa) remains extremely poor. To provide optimal treatment for each patient with Pca, superior biomarkers are urgently needed in all phases of management from early detection to staging, treatment monitoring, and prognosis. In the blood of patients with cancer, circulating tumor cells (CTCs) and cell-free nucleic acids (cfNAs), such as DNA, mRNA, and noncoding RNA have been recognized. In the recent years, their presence in the blood has encouraged researchers to investigate their potential use as novel blood biomarkers, and numerous studies have demonstrated their potential clinical utility as a biomarker for certain types of cancer. This concept, called “liquid biopsy” has been focused on as a less invasive, alternative approach to cancer tissue biopsy for obtaining genetic and epigenetic aberrations that contribute to oncogenesis and cancer progression. In this article, we review the available literature on CTCs and cfNAs in patients with cancer, particularly focusing on PCa, and discuss future perspectives in this field.