MicroRNA expression alterations are linked to tumorigenesis and non-neoplastic processes in pancreatic ductal adenocarcinoma

The role of circulating miRNAs and CA19-9 in pancreatic cancer diagnosis

Diagnosis and treatment of pancreatic ductal adenocarcinoma (PA) remains a challenge in clinical practice. The aim of this study was to assess the role of microRNAs (miRNAs-21, -23a, -100, -107, -181c, -210) in plasma and tissue as possible biomarkers in the diagnosis of PA. Samples of plasma (PAp-n = 13), pancreatic tumors (PAt-n = 18), peritumoral regions (PPT-n = 9) were collected from patients during the surgical procedure. The control group consisted of samples from patients submitted to pancreatic surgery for trauma or cadaveric organs (PC-n = 7) and healthy volunteers donated blood (PCp-n = 6). The expression profile of microRNAs was measured in all groups using RT-PCR, serum CA19-9 levels were determined in PA and PC. In tissue samples, there was a difference in the expression of miRNAs-21, -210 (p < 0.05) across the PAt, PC and PPT groups. The PAp showed overexpression of miRNAs-181c, -210 (p < 0.05) when compared to PCp. The combination of miRNAs-21, -210 tissue expression and serum CA19-9 showed 100% accuracy in the diagnosis of PA, as well as miR-181c expression in the plasma (PApxPCp). The expression of microRNAs in plasma proved to be a promising tool for a noninvasive detection test for PA, as well as further studies will evaluate the utility of microRNAs expression as biomarkers for prognostic and response to therapy in PA.

LncIMF2 promotes adipogenesis in porcine intramuscular preadipocyte through sponging MiR-217

Intramuscular fat is positively related to meat quality including tenderness, flavor, and juiciness. Long noncoding RNA (LncRNA) plays a vital role in regulating adipogenesis. However, it is largely unknown about lncRNAs associated with porcine intramuscular adipocyte adipogenesis. In the present study, we focus on a novel LncRNA, which is named lncIMF2, associated with adipogenesis by our previous RNA-sequence analysis and bioinformatics analysis. We demonstrated LncIMF2 knockdown inhibited the proliferation of porcine intramuscular adipocytes while expression of cell cycle-related genes was decreased. Besides, we found LncIMF2 knockdown inhibited expression of adipogenic differentiation marker genes including PPARγ (Peroxisome proliferator-activated reporter gamma) and ATGL (Adipose triglyceride lipase). Similarly, overexpression of LncIMF2 promotes proliferation and differentiation of porcine intramuscular preadipocytes. Moreover, we proved that IncIMF2 acts as a molecular sponge for MicroRNA-217 (miR-217), which has been found associated with adipogenesis, thereby affecting the expression of the miR-217 target gene. Collectively, our findings will contribute to a deeper understanding of the role of LncRNA in pig IMF deposition for the improvement of meat quality.

Non-coding RNAs in pancreatic ductal adenocarcinoma: New approaches for better diagnosis and therapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies with a 5-year survival rate less than 8%, which has remained unchanged over the last 50 years. Early detection is particularly difficult due to the lack of disease-specific symptoms and a reliable biomarker. Multimodality treatment including chemotherapy, radiotherapy (used sparingly) and surgery has become the standard of care for patients with PDAC. Carbohydrate antigen 19-9 (CA 19-9) is the most common diagnostic biomarker; however, it is not specific enough especially for asymptomatic patients. Non-coding RNAs are often deregulated in human malignancies and shown to be involved in cancer-related mechanisms such as cell growth, differentiation, and cell death. Several micro, long non-coding and circular RNAs have been reported to date which are involved in PDAC. Aim of this review is to discuss the roles and functions of non-coding RNAs in diagnosis and treatments of PDAC.

MicroRNA-203-3p inhibits the proliferation, invasion and migration of pancreatic cancer cells by downregulating fibroblast growth factor 2

Aberrant expression of fibroblast growth factor 2 (FGF2) is a major cause of poor prognosis in patients with pancreatic cancer. MicroRNA (miRNA/miR) miR-203-3p is a newly identified miRNA that can affect the biological behavior of tumors. The present study investigated the function of miR-203-3p on the regulation of FGF2 expression, and its role in pancreatic cancer cell proliferation, apoptosis, invasion and migration. Reverse transcription-quantitative PCR was used to determine the mRNA expression levels of miR-203-3p and FGF2 in vitro. Cell Counting Kit-8, Annexin V-APC/7-AAD double-staining Apoptosis Detection kit, wound healing and Transwell assays were used to determine the proliferation, apoptosis, migration and invasion of pancreatic cancer cells. The binding of miR-203-3p to FGF2 was assessed by a luciferase reporter assay. The results demonstrated that miR-203-3p expression was downregulated in pancreatic cancer cells. Gain- and loss-of-function experiments indicated that miR-203-3p inhibited the proliferation, migration and invasion, and promoted the apoptosis of pancreatic cancer cells in vitro. In addition, it was found that alteration of miR-203-3p abolished the promoting effects of FGF2 on pancreatic cancer cells. The present study demonstrated that FGF2 significantly promoted the proliferation, invasion and migration of pancreatic cancer cells. The mechanism involved the binding of miR-203-3p to the 3′-untranslated region of FGF2 mRNA, resulting in the downregulation of FGF2. In conclusion, miR-203-3p inhibited FGF2 expression, regulated the proliferation and inhibited the invasion and migration of pancreatic cancer cells.

MicroRNAs: emerging driver of cancer perineural invasion

The perineural invasion (PNI), which refers to tumor cells encroaching on nerve, is a clinical feature frequently occurred in various malignant tumors, and responsible for postoperative recurrence, metastasis and decreased survival. The pathogenesis of PNI switches from 'low-resistance channel' hypothesis to 'mutual attraction' theory between peripheral nerves and tumor cells in perineural niche. Among various molecules in perineural niche, microRNA (miRNA) as an emerging modulator of PNI through generating RNA-induced silencing complex (RISC) to orchestrate oncogene and anti-oncogene has aroused a wide attention. This article systematically reviewed the role of microRNA in PNI, promising to identify new biomarkers and offer cancer therapeutic targets.

MicroRNA-155 acts as a diagnostic and prognostic biomarker for oesophageal squamous cell carcinoma

MicroRNA-155 is over-expressed in many human cancers, but researches on its association with malignant oesophageal squamous cell carcinoma (ESCC) are limited. The aim of the present study was to evaluate the potential value of miR-155 as a biomarker for ESCC diagnosis and prognosis. In this study, we found that miR-155 was significantly increased in ESCC tissues compared with the paired adjacent tissues and healthy normal controls (p < .001), according to qRT-PCR, which suggested that miR-155 might act as an oncogene in ESCC. In addition, clinical features such as the depth of tumour invasion, tumour size, and TNM stage were all proved to impact the expression of miR-155 (p < .01). Then, ROC curve analysis, reaching an AUC of 0.870, and a sensitivity and specificity of 83.5% and 77.5%, respectively, revealed that miR-155 was a predictive factor for ESCC. As well, high expression of miR-155 was associated with poor overall survival of the patients (log-rank test, p = .004), according to Kaplan-Meier analysis. MiR-155 might be an independent predictor for overall survival in ESCC patients, manifested by Cox regression analysis (HR = 16.94, 95%CI = 3.33-86.12, p = .001). Taken together, miR-155 could be an independent diagnostic and prognostic biomarker for ESCC.

MiR-21 in the Cancers of the Digestive System and Its Potential Role as a Diagnostic, Predictive, and Therapeutic Biomarker

MicroRNAs (miRNAs) are small non-coding RNAs. They can regulate the expression of their target genes, and thus, their dysregulation significantly contributes to the development of cancer. Growing evidence suggests that miRNAs could be used as cancer biomarkers. As an oncogenic miRNA, the roles of miR-21 as a diagnostic and prognostic biomarker, and its therapeutic applications have been extensively studied. In this review, the roles of miR-21 are first demonstrated via its different molecular networks. Then, a comprehensive review on the potential targets and the current applications as a diagnostic and prognostic cancer biomarker and the therapeutic roles of miR-21 in six different cancers in the digestive system is provided. Lastly, a brief discussion on the challenges for the use of miR-21 as a therapeutic tool for these cancers is added.

Umbilical cord miRNAs to predict neonatal early onset sepsis

OBJECTIVE

To determine if miRNA (miR) expression in umbilical cord blood and umbilical cord tissue differs between neonates with early onset sepsis (EOS) versus neonates without true infection.

METHODS

Retrospective case-control study design of human patients with EOS (n = 8), presumed sepsis (N = 12) and non-infected control patients (N = 21). Differential expression of >300 miRs was examined using the MIHS-3001ZE-miScript miRNA PCR Array Human miFinder 384HC. Expression levels of miRs were normalized using the global Ct mean of expressed miR and compared between groups. Data analysis was performed using GeneGlobe data analysis software. Ratios of over and under-expressed miRs were calculated and compared between groups using receiver operating characteristic (ROC) curves.

RESULTS

Both umbilical cord plasma and umbilical cord tissue revealed several miRs with differential expression with little overlap between the two specimen types. The most overexpressed miR in plasma of EOS patients was miR-211-5p and the most overexpressed in EOS cord tissue was miR-223-5p. ROC curves comparing the ratios of over and under-expressed miRs for EOS patients and controls resulted in an area under the curve of 0.787 for cord plasma (miR-211-5p/miR-142-3p) and 0.988 for umbilical cord tissue (miR-223-5p/miR-22-3p), indicating good discrimination.

CONCLUSIONS

miRs show differential expression in EOS versus non-infected controls and presumed sepsis. A ratio of over and under-expressed miRs can provide a potentially sensitive and specific diagnostic test for EOS.

MicroRNA-sensitive oncolytic measles virus for chemovirotherapy of pancreatic cancer

Advanced pancreatic cancer is characterized by few treatment options and poor outcomes. Oncolytic virotherapy and chemotherapy involve complementary pharmacodynamics and could synergize to improve therapeutic efficacy. Likewise, multimodality treatment may cause additional toxicity, and new agents have to be safe. Balancing both aims, we generated an oncolytic measles virus for 5-fluorouracil-based chemovirotherapy of pancreatic cancer with enhanced tumor specificity through microRNA-regulated vector tropism. The resulting vector encodes a bacterial prodrug convertase, cytosine deaminase-uracil phosphoribosyl transferase, and carries synthetic miR-148a target sites in the viral F gene. Combination of the armed and targeted virus with 5-fluorocytosine, a prodrug of 5-fluorouracil, resulted in cytotoxicity toward both infected and bystander pancreatic cancer cells. In pancreatic cancer xenografts, a single intratumoral injection of the virus induced robust in vivo expression of prodrug convertase. Based on intratumoral transgene expression kinetics, we devised a chemovirotherapy regimen to assess treatment efficacy. Concerted multimodality treatment with intratumoral virus and systemic prodrug administration delayed tumor growth and prolonged survival of xenograft-bearing mice. Our results demonstrate that 5-fluorouracil-based chemovirotherapy with microRNA-sensitive measles virus is an effective strategy against pancreatic cancer at a favorable therapeutic index that warrants future clinical translation.

Improving Gemcitabine Sensitivity in Pancreatic Cancer Cells by Restoring miRNA-217 Levels

Chemoresistance is a major problem in the therapeutic management of pancreatic cancer, concurring to poor clinical outcome. A number of mechanisms have been proposed to explain resistance to gemcitabine, a standard of care for this malignancy, among which is included aberrant miRNA expression. In the current study, we investigated the role of miR-217, which is strongly down-regulated in cancerous, compared to normal, pancreatic tissues or cells, in sensitizing human pancreatic cancer cell lines to this drug. The low expression of miR-217 in pancreatic cancer patients was confirmed in two gene expression datasets (GSE41372 and GSE60980), and the prognostic value of two target genes (ANLN and TRPS1), was estimated on clinical data from the Tumor Cancer Genome Atlas (TCGA). Transfecting miR-217 mimic in pancreatic cancer cells reduced viability, enhanced apoptosis, and affected cell cycle by promoting a S phase arrest in gemcitabine-treated cells. Moreover, in drug-exposed cells subjected to miR-217 forced expression, a down-regulation for several genes involved in cancer drug resistance was observed, many of which are cell cycle regulators, such as CCND1, CCNE1, CDK2, CDKN1A, CDKN1B, while others, such as ARNT, BRCA1, BRCA2, ELK1, EGFR, ERBB4, and RARA are involved in proliferation and cell cycle progression. Our results support the notion that miR-217 enhances pancreatic cancer sensitivity to gemcitabine, mainly impairing cell cycle progression.

lncRNA-XLOC_012370 Promotes the Development of Pancreatic Cancer and Inactivates the NF-κB Pathway Through miR-140-5p

Pancreatic cancer is a high incidence, high degree of malignancy, and high mortality in the digestive system tumor. The incidence of pancreatic cancer in China has increased nearly six folds in the past 20 years, ranking fifth in the mortality rate of malignant tumors, so it is particularly important to actively explore clinical indicators with better diagnostic significance for pancreatic cancer. LncRNA performs an essential regulatory function in the occurrence, development, and metastasis of many kinds of tumors, playing both a carcinogenic role and a tumor suppressor gene. Here, we demonstrated the function and mechanism of LncRNA-XLOC_012370 in the development of pancreatic cancer. In our research, the abnormal upregulation of XLOC_012370 was observed in pancreatic cancer patients’ tumor tissues. XLOC_012370 was related to tumor stage, lymph node metastasis, and overall survival. Silencing of XLOC_012370 prevented the proliferation, migration, and invasion via the NF-κB signal pathway. Further, miR-140-5p was identified as the target and downstream of XLOC_012370 and involved in pancreatic cancer progression. In vivo, knockdown of XLOC_012370 inhibited tumor growth via the NF-κB signal pathway. In conclusion, lncRNA-XLOC_012370 is closely related to some malignant clinicopathological features and prognosis of pancreatic cancer. Thus the miR-140-5p/NF-κB signal pathway might represent a promising treatment strategy to combat pancreatic cancer.

Molecular Approaches Using Body Fluid for the Early Detection of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most malignant form of gastrointestinal tumor and is the fourth leading cause of deaths due to cancer in Japan. This cancer shows a poor outcome due to the difficulty of its early diagnosis and its rapid growth. Once this disease becomes clinically evident, it is frequently accompanied by distant metastasis at the time of diagnosis. A recent multicenter study in Japan revealed that patients with the early stage of this disease (stage 0 and I) showed favorable prognosis after surgical resection, indicating the importance of early detection for improvement of PDAC prognosis. PDAC develops through a stepwise progression from the precursor lesion, and over the last few decades molecular analyses have shown the detailed genetic alterations that occur in this process. Since advances in molecular technologies have enabled the detection of genetic changes from a very small quantity of samples, a large number of non-invasive molecular approaches have been utilized in an attempt to find precursor or non-invasive carcinoma lesions. In this review, the current efforts in terms of the molecular approaches applied for the early detection of PDAC-especially using body fluids such as pancreatic juice, blood, and saliva-are summarized.

Current State of "Omics" Biomarkers in Pancreatic Cancer

Pancreatic cancer is one of the most fatal malignancies and the seventh leading cause of cancer-related deaths related to late diagnosis, poor survival rates, and high incidence of metastasis. Unfortunately, pancreatic cancer is predicted to become the third leading cause of cancer deaths in the future. Therefore, diagnosis at the early stages of pancreatic cancer for initial diagnosis or postoperative recurrence is a great challenge, as well as predicting prognosis precisely in the context of biomarker discovery. From the personalized medicine perspective, the lack of molecular biomarkers for patient selection confines tailored therapy options, including selecting drugs and their doses or even diet. Currently, there is no standardized pancreatic cancer screening strategy using molecular biomarkers, but CA19-9 is the most well known marker for the detection of pancreatic cancer. In contrast, recent innovations in high-throughput techniques have enabled the discovery of specific biomarkers of cancers using genomics, transcriptomics, proteomics, metabolomics, glycomics, and metagenomics. Panels combining CA19-9 with other novel biomarkers from different "omics" levels might represent an ideal strategy for the early detection of pancreatic cancer. The systems biology approach may shed a light on biomarker identification of pancreatic cancer by integrating multi-omics approaches. In this review, we provide background information on the current state of pancreatic cancer biomarkers from multi-omics stages. Furthermore, we conclude this review on how multi-omics data may reveal new biomarkers to be used for personalized medicine in the future.

Targeted Therapies for Pancreatic Cancer: Overview of Current Treatments and New Opportunities for Personalized Oncology

Cytotoxic chemotherapy remains the only treatment option for most pancreatic ductal adenocarcinoma patients. Currently, the median overall survival of patients with advanced disease rarely exceeds 1 year. The complex network of pancreatic cancer composed of immune cells, endothelial cells, and cancer-associated fibroblasts confers intratumoral and intertumoral heterogeneity with distinct proliferative and metastatic propensity. This heterogeneity can explain why tumors do not behave uniformly and are able to escape therapy. The advance in technology of whole-genome sequencing has now provided the possibility of identifying every somatic mutation, copy-number change, and structural variant in a given cancer, giving rise to personalized targeted therapies. In this review, we provide an overview of the current and emerging treatment strategies in pancreatic cancer. By highlighting new paradigms in pancreatic ductal adenocarcinoma treatment, we hope to stimulate new thoughts for clinical trials aimed at improving patient outcomes.

Panel of serum miRNAs as potential non-invasive biomarkers for pancreatic ductal adenocarcinoma

Early-stage diagnosis of pancreatic ductal adenocarcinoma (PDAC) is difficult due to non-specific symptoms. Circulating miRNAs in body fluids have been emerging as potential non-invasive biomarkers for diagnosis of many cancers. Thus, this study aimed to assess a panel of miRNAs for their ability to differentiate PDAC from chronic pancreatitis (CP), a benign inflammatory condition of the pancreas. Next-generation sequencing was performed to identify miRNAs present in 60 FFPE tissue samples (27 PDAC, 23 CP and 10 normal pancreatic tissues). Four up-regulated miRNAs (miR-215-5p, miR-122-5p, miR-192-5p, and miR-181a-2-3p) and four down-regulated miRNAs (miR-30b-5p, miR-216b-5p, miR-320b, and miR-214-5p) in PDAC compared to CP were selected based on next-generation sequencing results. The levels of these 8 differentially expressed miRNAs were measured by qRT-PCR in 125 serum samples (50 PDAC, 50 CP, and 25 healthy controls (HC)). The results showed significant upregulation of miR-215-5p, miR-122-5p, and miR-192-5p in PDAC serum samples. In contrast, levels of miR-30b-5p and miR-320b were significantly lower in PDAC as compared to CP and HC. ROC analysis showed that these 5 miRNAs can distinguish PDAC from both CP and HC. Hence, this panel can serve as a non-invasive biomarker for the early detection of PDAC.

MicroRNA-217: A regulator of human cancer

As highly conserved non-coding RNAs of approximately 18-24 nucleotides, microRNAs (miRNAs) regulate the expression of target genes. Multiple studies have demonstrated that miRNAs participate in the regulation of human cancer. MircoRNA-217 (miR-217) participates in the regulation of various tumors by specifically binding target genes and post-transcriptional regulation. In recent years, there have been numerous reports about miR-217 in tumor progression. MiR-217 is known mainly as a tumor suppressor, although some studies have shown that it functions as an oncomiR. Here, we review the current research related to miR-217, including its role in tumor progression and the molecular mechanisms.

Pilot study identifying circulating miRNA signature specific to alcoholic chronic pancreatitis and its implication on alcohol-mediated pancreatic tissue injury

Background and Aim

Alcohol exerts its effects on organs in multiple ways. Alcoholic chronic pancreatitis (ACP) is a disease in which alcohol triggers the pathological changes in pancreas, leading to chronic inflammation and fibrosis. The molecular mechanism behind these changes is not clear. Identification of key circulating miRNA changes in ACP patients and determination of the fraction that is secreted from diseased pancreas not only could serve as potential biomarker for assessing disease severity, but also could help identifying the molecular alterations prevailing in the organ precipitating the disease, to some extent.

Methods

We performed microRNA microarray using the Affymetrix miRNA 4.0 platform to identify differentially expressed miRNAs in serum of ACP patients as compared to alcoholic control individuals and then found out how many of them could be pancreas-specific and exosomally secreted. We further analyzed a pancreatitis-specific gene expression data set to find out the differentially expressed genes in diseased pancreas and explored the possible role of those selected miRNAs in regulation of gene expression in ACP.

Results

We identified 14 miRNAs differentially expressed in both serum and pancreas and also identified their experimentally validated targets. Transcription factors modulating the miRNA expression in an alcohol-dependent manner were also identified and characterized to derive the miRNA-gene-TF interaction network responsible for progression of the disease.

Conclusions

Differentially expressed miRNA signature demonstrated significant changes in both pro- and anti-inflammatory pathways probably balancing the chronic inflammation in the pancreas. Our findings also suggested possible involvement of pancreatic stellate cells in disease progression.

Overcoming negative predictions of microRNA expressions to gemcitabine response with FOLFIRINOX in advanced pancreatic cancer patients

FOLFIRINOX is superior to gemcitabine in patients with pancreatic cancer, but this regimen is associated with toxicity and biomarkers for response are warranted. MicroRNAs can mediate drug resistance and could provide predictive information. Altered expressions of several microRNAs including miR-21-5p, miR-10b-5p and miR-34a-5p have been previously linked to a worse response to gemcitabine. We investigated the influence of expression levels in tumor tissue of those three microRNAs on outcome to FOLFIRINOX. Twenty-nine patients with sufficient formalin-fixed paraffin-embedded tumor tissue were identified. There was no significant association between high and low expression groups for these three microRNA. We conclude that polychemotherapy combination can overcome intrinsic negative prognostic factors.

Implementing biological markers as a tool to guide clinical care of patients with pancreatic cancer

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A major obstacle for the effective treatment of PDAC is its molecular heterogeneity.

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Stratification of PDAC using markers highly specific, reproducible, sensitive, easily measurable and inexpensive is necessary.

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At the early stages, clinician’s priority lies in rapid diagnosis, so that the patient receives surgery without delay.

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At advanced disease stages, priority is to determine the tumor subtype and select a suitable effective treatment.

A major obstacle for the effective treatment of pancreatic ductal adenocarcinoma (PDAC) is its molecular heterogeneity, reflected by the diverse clinical outcomes and responses to therapies that occur. The tumors of patients with PDAC must therefore be closely examined and classified before treatment initiation in order to predict the natural evolution of the disease and the response to therapy. To stratify patients, it is absolutely necessary to identify biological markers that are highly specific and reproducible, and easily measurable by inexpensive sensitive techniques. Several promising strategies to find biomarkers are already available or under development, such as the use of liquid biopsies to detect circulating tumor cells, circulating free DNA, methylated DNA, circulating RNA, and exosomes and extracellular vesicles, as well as immunological markers and molecular markers. Such biomarkers are capable of classifying patients with PDAC and predicting their therapeutic sensitivity. Interestingly, developing chemograms using primary cell lines or organoids and analyzing the resulting high-throughput data via artificial intelligence would be highly beneficial to patients. How can exploiting these biomarkers benefit patients with resectable, borderline resectable, locally advanced, and metastatic PDAC? In fact, the utility of these biomarkers depends on the patient's clinical situation. At the early stages of the disease, the clinician's priority lies in rapid diagnosis, so that the patient receives surgery without delay; at advanced disease stages, where therapeutic possibilities are severely limited, the priority is to determine the PDAC tumor subtype so as to estimate the clinical outcome and select a suitable effective treatment.

MicroRNA-148a-3p suppresses epithelial-to-mesenchymal transition and stemness properties via Wnt1-mediated Wnt/β-catenin pathway in pancreatic cancer

Although miR-148a-3p has been reported to function as a tumour suppressor in various cancers, the molecular mechanism of miR-148a-3p in regulating epithelial-to-mesenchymal transition (EMT) and stemness properties of pancreatic cancer (PC) cells remains to be elucidated. In the present study, we demonstrated that miR-148a-3p expression was remarkably down-regulated in PC tissues and cell lines. Moreover, low expression of miR-148a-3p was associated with poorer overall survival (OS) in patients with PC. In vitro, gain-of-function and loss-of-function experiments showed that miR-148a-3p suppressed EMT and stemness properties as well as the proliferation, migration and invasion of PC cells. A dual-luciferase reporter assay demonstrated that Wnt1 was a direct target of miR-148a-3p, and its expression was inversely associated with miR-148a-3p in PC tissues. Furthermore, miR-148a-3p suppressed the Wnt/β-catenin pathway via down-regulation of Wnt1. The effects of ectopic miR-148a-3p were rescued by Wnt1 overexpression. These biological functions of miR-148a-3p in PC were also confirmed in a nude mouse xenograft model. Taken together, these findings suggest that miR-148a-3p suppresses PC cell proliferation, invasion, EMT and stemness properties via inhibiting Wnt1-mediated Wnt/β-catenin pathway and could be a potential prognostic biomarker as well as a therapeutic target in PC.

Non-coding RNA biomarkers in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, which is usually diagnosed at an advanced stage. The late disease diagnosis, the limited availability of effective therapeutic interventions and lack of robust diagnostic biomarkers, are some of the primary reasons for the dismal 5-year survival rates (∼8%) in patients with PDAC. The pancreatic cancer develops through accumulation of a series of genomic and epigenomic alterations which lead to the transformation of normal pancreatic epithelium into an invasive carcinoma - a process that can take up to 15-20 years to develop, from the occurrence of first initiating mutational event. These facts highlight a unique window of opportunity for the earlier detection of PDAC, which could allow timely disease interception and improvement in the overall survival outcomes in patients suffering from this fatal malignancy. Non-coding RNAs (ncRNAs) have been recognized to play a central role in PDAC pathogenesis and are emerging as attractive candidates for biomarker development in various cancers, including PDAC. More specifically, the ncRNAs play a pivotal role in PDAC biology as they affect tumor growth, migration, and invasion by regulating cellular processes including cell cycle, apoptosis, and epithelial-mesenchymal transition. In this review, we focus on three types of well-established ncRNAs - microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) - and discuss their potential as diagnostic, prognostic and predictive biomarkers in PDAC.

Posttranscriptional regulation of thiamin transporter-1 expression by microRNA-200a-3p in pancreatic acinar cells

The water-soluble vitamin B1 (thiamin) plays essential roles in normal metabolism and function of all human/mammalian cells, including the pancreatic acinar cells (PACs). PACs obtain thiamin from their surrounding circulation via transport across the plasma membrane, a process that is mediated by thiamin transporter (THTR)-1 and THTR-2. We have previously characterized different aspects of thiamin uptake by mouse and human primary PACs, but little is known about posttranscriptional regulation of the uptake event. We addressed this by focusing on the predominant thiamin transporter THTR-1 (encoded by SLC19A2 gene) in PACs. Transfecting pmirGLO-SLC19A2 3'-untranslated region (UTR) into mouse-derived PAC 266-6 cells leads to a significant reduction in luciferase activity compared with cells transfected with empty vector. Subjecting the SLC19A2 3'-UTR to different in silico algorithms identified multiple putative microRNA binding sites in this region. Focusing on miR-200a-3p (since it is highly expressed in mouse and human pancreas), we found that transfecting PAC 266-6 and human primary PACs (hPACs) with mimic miR-200a-3p leads to a significant inhibition of THTR-1 expression (both protein and mRNA levels) and in thiamin uptake. In contrast, transfection by miR-200a-3p inhibitor leads to an increase in THTR-1 expression and thiamin uptake. Additionally, truncating the region carrying miR-200a-3p binding site in SLC19A2 3'-UTR and mutating the binding site lead to abrogation in the inhibitory effect of this microRNA on luciferase activity in PAC 266-6. These results demonstrate that expression of THTR-1 and thiamin uptake in PACs is subject to posttranscriptional regulation by microRNAs.NEW & NOTEWORTHY The findings of this study show, for the first time, that the membrane transporter of vitamin B1, i.e., thiamin transporter-1 (THTR-1), is subject to regulation by microRNAs (specifically miR-200a-3p) in mouse and human primary pancreatic acinar cells (PACs). The results also show that this posttranscriptional regulation has functional consequences on the ability of PACs to take in the essential micronutrient thiamin.

miR-148a Regulates the Stem Cell-Like Side Populations Distribution by Affecting the Expression of ACVR1 in Esophageal Squamous Cell Carcinoma

Introduction

Esophageal squamous cell carcinoma (ESCC) is a malignant tumor disease with high mortality and morbidity rates, especially for a terminal cancer. At present, the prognosis and treatment of ESCC cannot effectively control or inhibit the spread and proliferation of tumor cells. microRNAs, a class of small spliced RNAs, are essential in the regulation of tumorigenesis and tumor cell migration and proliferation. microRNAs interact with target mRNA to silence gene expression and degrade mRNA, thereby inhibiting the expression of tumor genes or impairing the expression of tumor suppressor genes.

Methods

A total of 20 human ESCC samples were collected from the Affiliated Tumor Hospital of Xinjiang Medical University. Eca109 and Kyse510 cells, which are ESCC cell lines, were subjected to FACS analysis to get side population (SP) cells and non-SP cells. Cell cycle and cell proliferation were analyzed by flow cytometry. Cell migration and invasion were detected using a transwell assay. Quantitative PCR and Western blot were performed to analyze the expression levels of ABCG2, KLF4, OCT4, and ACVR1, which are related to the stemness of stem cells. The target genes of hsa-miR-148a were predicted using TargetScan (version 7.2) and verified by a dual luciferase reporter assay. A chromatin immunoprecipitation (ChIP) assay was carried out to demonstrate direct interaction between miR-148a and ACVR1.

Results

The expression of miR-148a was significantly down-regulated in ESCC cells and significantly decreased in SP esophageal squamous cells when compared to the tumor cells. By analyzing the stem cell stemness of ESCC, overexpression of miR-148a decreased the expression of ABCG2, KLF4, SOX2, OCT4, and Nanog, indicating that miR-148a may regulate stem cell function. Target gene prediction and functional annotation of miR-148a suggested that miR-148a is involved in stem cell stemness of ESCC via ACVR1. Expression of the dual luciferase-labeled gene indicates that overexpression of miR-148a inhibits the expression of ACVR1, thereby affecting stem cell stemness.

Conclusion

miR-148a regulates the stem cell-like side populations distribution by inhibiting the expression of ACVR1 in ESCC. miR-148a may be a promising targeted therapy for ESCC.

Use of Biomarkers and Imaging for Early Detection of Pancreatic Cancer

Pancreatic cancer remains one of the deadliest cancers worldwide, and it is typically diagnosed late, with a poor prognosis. Early detection is the most important underlying factor for improving the prognosis of pancreatic cancer patients. One of the most effective strategies for detecting cancers at an early stage is screening of the general population. However, because of the low incidence of pancreatic cancer in the general population, the stratification of subjects who need to undergo further examinations by invasive and expensive modalities is important. Therefore, minimally invasive modalities involving biomarkers and imaging techniques that would facilitate the early detection of pancreatic cancer are highly needed. Multiple types of new blood biomarkers have recently been developed, including unique post-translational modifications of circulating proteins, circulating exosomes, microRNAs, and circulating tumor DNA. We previously reported that circulating apolipoprotein A2 undergoes unique processing in the bloodstream of patients with pancreatic cancer and its precancerous lesions. Additionally, we recently demonstrated a new method for measuring pancreatic proton density in the fat fraction using a fat–water magnetic resonance imaging technique that reflects pancreatic steatosis. In this review, we describe recent developments in potential biomarkers and imaging modalities for the early detection and risk stratification of pancreatic cancer, and we discuss current strategies for implementing screening programs for pancreatic cancer.

Epigenetic Landscape in Pancreatic Ductal Adenocarcinoma: On the Way to Overcoming Drug Resistance?

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive solid malignancies due to the rapid rate of metastasis and high resistance to currently applied cancer therapies. The complex mechanism underlying the development and progression of PDAC includes interactions between genomic, epigenomic, and signaling pathway alterations. In this review, we summarize the current research findings on the deregulation of epigenetic mechanisms in PDAC and the influence of the epigenome on the dynamics of the gene expression changes underlying epithelial–mesenchymal transition (EMT), which is responsible for the invasive phenotype of cancer cells and, therefore, their metastatic potential. More importantly, we provide an overview of the studies that uncover potentially actionable pathways. These studies provide a scientific basis to test epigenetic drug efficacy in synergy with other anticancer therapies in future clinical trials, in order to reverse acquired therapy resistance. Thus, epigenomics has the potential to generate relevant new knowledge of both a biological and clinical impact. Moreover, the potential, hurdles, and challenges of predictive biomarker discoveries will be discussed, with a special focus on the promise of liquid biopsies.

Potential microRNA panel for the diagnosis and prediction of overall survival of hepatocellular carcinoma with hepatitis B virus infection

BACKGROUND

In hepatocellular carcinoma (HCC), abnormal expression of multiple microRNAs (miRNAs) has been shown to be involved in the malignant biological behavior of liver cancer. The vast majority of liver cancer cases in China are closely related to hepatitis B virus (HBV) infection, but there are few studies on the changes of miRNA expression in the progression from HBV infection to hepatoma.

AIM

To explore the role of miRNAs in the progression of HBV infection to cirrhosis and even to liver cancer.

METHODS

We screened differentially expressed miRNAs in 40 HBV cirrhosis, 40 normal and 15 HCC tissues by using a TaqMan Low Density Array and real time quantitative polymerase chain reaction. To evaluate the power of the selected miRNAs to predict disease, we calculated the area under the receiver-operating-characteristic curves. The overall survival of HBV cirrhosis patients was analyzed via Kaplan-Meier analysis.

RESULTS

The levels of miR-375, miR-122 and miR-143 were significantly lower in HBV cirrhosis tissues, while miR-224 was significantly higher than in the controls (P < 0.0001). The area under the curves of the receiver-operating-characteristic curve for the 4-miRNA panel was 0.991 (95%CI: 0.974-1). Patients with a lower expression level of miR-224 or higher expression levels of miR-375, miR-122 and miR-143 had longer overall survival.

CONCLUSION

The four miRNAs (miR-375, miR-122, miR-143 and miR-224) may be helpful for early diagnosis of HBV infection, HBV cirrhosis, and prediction of its overall survival.

Non-coding RNAs in Pancreatic Ductal Adenocarcinoma

Non-coding RNAs (ncRNAs) are reported to be expressed in human cancers, including pancreatic ductal adenocarcinoma (PDAC). These ncRNAs affect the growth, migration and invasion of tumor cells by regulating cell cycle and apoptosis, as well as playing important roles in epigenetic processes, transcription and post-transcriptional regulation. It is still unclear whether alterations in ncRNAs influence PDAC development and progression. Because of this, analysis based on existing data on ncRNAs, which are crucial for modulating pancreatic tumorigenesis, will be important for future research on PDAC. Here, we summarize ncRNAs with tumor-promoting functions: HOTAIR, HOTTIP, MALAT1, lncRNA H19, lncRNA PVT1, circ-RNA ciRS-7, circ-0030235, circ-RNA_100782, circ-LDLRAD3, circ-0007534, circRHOT1, circZMYM2, circ-IARS, circ-RNA PDE8A, miR-21, miR-155, miR-221/222, miR-196b, miR-10a. While others including GAS5, MEG3, and lncRNA ENST00000480739, has_circ_0001649, miR-34a, miR-100, miR-217, miR-143 inhibit the proliferation and invasion of PDAC. Hence, we summarize the functions of ncRNAs in the occurrence, development and metastasis of PDAC, with the goal to provide guidance in the clinical diagnosis and treatment of PDAC.

The Microrna-143/145 Cluster in Tumors: A Matter of Where and When

The establishment and spreading of cancer involve the acquirement of many biological functions including resistance to apoptosis, enhanced proliferation and the ability to invade the surrounding tissue, extravasate from the primary site, survive in circulating blood, and finally extravasate and colonize distant organs giving origin to metastatic lesions, the major cause of cancer deaths. Dramatic changes in the expression of protein coding genes due to altered transcription factors activity or to epigenetic modifications orchestrate these events, intertwining with a microRNA regulatory network that is often disrupted in cancer cells. microRNAs-143 and -145 represent puzzling players of this game, with apparently contradictory functions. They were at first classified as tumor suppressive due to their frequently reduced levels in tumors, correlating with cell survival, proliferation, and migration. More recently, pro-oncogenic roles of these microRNAs have been described, challenging their simplistic definition as merely tumor-suppressive. Here we review their known activities in tumors, whether oncogenic or onco-suppressive, and highlight how their expression and functions are strongly dependent on their complex regulation downstream and upstream of cytokines and growth factors, on the cell type of expression and on the specific tumor stage.

MiR-200c sensitizes Olaparib-resistant ovarian cancer cells by targeting Neuropilin 1

BACKGROUND

Ovarian cancer (OC) is the most lethal gynecological malignancy and the second leading cause of cancer-related death in women. Treatment with PARP inhibitors (PARPi), such as Olaparib, has been recently introduced for OC patients, but resistance may occur and underlying mechanisms are still poorly understood. The aim of this study is to identify target genes within the tumor cells that might cause resistance to Olaparib. We focused on Neuropilin 1 (NRP1), a transmembrane receptor expressed in OC and correlated with poor survival, which has been also proposed as a key molecule in OC multidrug resistance.

METHODS

Using three OC cell lines (UWB, UWB-BRCA and SKOV3) as model systems, we evaluated the biological and molecular effects of Olaparib on OC cell growth, cell cycle, DNA damage and apoptosis/autophagy induction, through MTT and colony forming assays, flow cytometry, immunofluorescence and Western blot analyses. We evaluated NRP1 expression in OC specimens and cell lines by Western blot and qRT-PCR, and used RNA interference to selectively inhibit NRP1. To identify miR-200c as a regulator of NRP1, we used miRNA target prediction algorithms and Pearsons' correlation analysis in biopsies from OC patients. Then, we used a stable transfection approach to overexpress miR-200c in Olaparib-resistant cells.

RESULTS

We observed that NRP1 is expressed at high levels in resistant cells (SKOV3) and is upmodulated in partially sensitive cells (UWB-BRCA) upon prolonged Olaparib treatment, leading to poor drug response. Our results show that the selective inhibition of NRP1 is able to overcome Olaparib resistance in SKOV3 cells. Moreover, we demonstrated that miR-200c can target NRP1 in OC cells, causing its downmodulation, and that miR-200c overexpression is a valid approach to restore Olaparib sensitivity in OC resistant cells.

CONCLUSIONS

These data demonstrate that miR-200c significantly enhanced the anti-cancer efficacy of Olaparib in drug-resistant OC cells. Thus, the combination of Olaparib with miRNA-based therapy may represent a promising treatment for drug resistant OC, and our data may help in designing novel precision medicine trials for optimizing the clinical use of PARPi.

Mechanism of miR-210 involved in epithelial-mesenchymal transition of pancreatic cancer cells under hypoxia

Purpose: To investigate the possible mechanism of miR-210 involved in epithelial-mesenchymal transition (EMT) of pancreatic cancer cells under hypoxia. Methods: In this study, we used the following approaches. Hypoxic microenvironment was stimulated in vitro, and the CCK-8 assay was used to analyze cell viability. The MiRNA expression level was measured by qRT-PCR. HOXA9, EMT-related proteins, and NF-κB activities were examined by immunoblotting assay. Dual luciferase reporter assay was used to assess whether HOXA9 was a target of miR-210.Results: Under hypoxia condition, miR-210, HIF-1α and NF-κB were increased, and the HOXA9 was reduced in PANC-1 cells. When miR-210 was overexpressed in normoxic PANC-1 cells, EMT epithelial markers of E-cadherin and β-catenin were down-regulated, and mesenchymal markers of vimentin and N-cadherin were up-regulated to promote cell migration/invasive ability, and the HOXA9 level was decreased. After HOXA9 level decreased, the sensitivity to chemotherapeutic drug of gemcitabine was reduced, NF-κB expression level and cell migration/invasive ability was enhanced. Whereas, miR-210 antagonist into hypoxic PANC-1 cells, which up-regulated E-cadherin, β-catenin level, and down-regulated vimentin and N-cadherin levels to decrease cell migration/invasive ability, and increase the HOXA9. Furthermore, increasing HOXA9 level decreased NF-κB expression level and cell migration/invasive ability, enhanced the sensitivity to gemcitabine. At last, miRDB and TargetScan predicted that HOXA9 was a target of miR-210, and dual luciferase reporter assay verified this hypothesis.Conclusion: MiR-210 inhibited the expression of HOXA9 to activate the NF-κB signaling pathway and mediated the occurrence of EMT of pancreatic cancer cells induced by HIF-1α under hypoxia.

MicroRNAs in Pancreatic Cancer: biomarkers, prognostic, and therapeutic modulators

A severe lack of early diagnosis coupled with resistance to most available therapeutic options renders pancreatic cancer as a major clinical concern. The limited efficacy of current treatments necessitates the development of novel therapeutic strategies that are based on an understanding of the molecular mechanisms involved in pancreatic cancer progression. MicroRNAs (miRNAs) are non-coding small RNAs that regulate the expression of multiple proteins in the post-translation process and thus have promise as biomarkers, prognostic agents, and as advanced pancreatic therapies. Profiling of deregulated miRNAs in pancreatic cancer can correlate to diagnosis, indicate optimal treatment and predict response to therapy. Furthermore, understanding the main effector genes in pancreatic cancer along with downstream pathways can identify possible miRNAs as therapeutic candidates. Additionally, obstacles to the translation of miRNAs into the clinic are also considered. Distinct miRNA expression profiles can correlate to stages of malignant pancreatic disease, and hold potential as biomarkers, prognostic markers and clinical targets. However, a limited understanding and validation of the specific role of such miRNAs stunts clinical application. Target prediction using algorithms provides a wide range of possible targets, but these miRNAs still require validation through pre-clinical studies to determine the knock-on genetic effects.

RBPJ inhibits the movability of endometrial carcinoma cells by miR-155/NF-κB/ROS pathway

Background

Recombination signal-binding protein J (RBPJ) is a crucial downstream effector of Notch signaling, which is involved cell proliferation, differentiation, and apoptosis. It plays an important role in tumorigenesis although the further studies and concrete evidence are still needed. Especially for endometrial carcinoma, the functions and mechanism of RBPJ are still elusive.

Methods

The RNA expressions of RBPJ, miR-155, NF-κB, TNF-α and κB-Ras1 were examined by rt-PCR, and their protein levels were determined by Western Blot. Their expressions were inhibited by transient transfection of related siRNAs. Wound healing and transwell invasion assays were performed in ECC003 cells for measuring the migration and invasion ability, respectively. The ROS levels were detected by flow cytometry with H2DCFDA.

Purpose

This study was designed to investigate biological characteristics and molecular pathway of RBPJ in endometrial carcinoma cells, which may provide a potential therapeutic target for the treatments against endometrial carcinoma.

Results

It was shown in our study that the expression levels of RBPJ were significantly downregulated in different endometrial carcinoma cell lines. And a siRNA-mediated reduction of RBPJ enhanced the migration and invasion ability of ECC003 obviously. Besides, the results showed that the reactive oxygen species (ROS) levels increase when inhibiting RBPJ. To investigate the molecular pathway of RBPJ, we examined the expression of nuclear factor-κB (NF-κB), NF-κB inhibitor interacting Ras-like protein 1 (κB-Ras1), tumor necrosis factor-α (TNF-α) and miR-155. The results suggested that the expression of NF-κB and TNF-α significantly was promoted, while κB-Ras1 was inhibited. An upregulated expression was observed with miR-155 as well, which suggested the inhibition of NF-κB signal pathway was mediated by miR-155. Our results of Notch intracellular domain (NICD) knockdown also demonstrated that NICD is required for the inhibition of RBPJ on miR-155. And knockdown of miR-155 could inhibit the mobility of endometrial carcinoma cells.

Conclusion

Our study suggested that RBPJ can inhibit the movability of endometrial carcinoma cells by miR-155/NF-κB/ROS pathway.

The Importance of microRNAs in RAS Oncogenic Activation in Human Cancer

microRNAs (miRNAs) regulate gene expression by modulating the translation of protein-coding RNAs. Their aberrant expression is involved in various human diseases, including cancer. Here, we summarize the experimental pieces of evidence that proved how dysregulated miRNA expression can lead to RAS (HRAS, KRAS, or NRAS) activation irrespective of their oncogenic mutations. These findings revealed relevant pathogenic mechanisms as well as mechanisms of resistance to target therapies. Based on this knowledge, potential approaches for the control of RAS oncogenic activation can be envisioned.

MicroRNAs in acute pancreatitis: From pathogenesis to novel diagnosis and therapy

Acute pancreatitis (AP) is an inflammatory disorder initiated by activation of pancreatic zymogens, leading to pancreatic injury and systemic inflammatory response. MicroRNAs (miRNAs) have emerged as important regulators of gene expression and key players in human physiological and pathological processes. Discoveries over the past decade have confirmed that altered expression of miRNAs is implicated in the pathogenesis of AP. Indeed, a number of miRNAs have been found to be dysregulated in various cell types involved in AP such as acinar cells, macrophages, and lymphocytes. These aberrant miRNAs can regulate acinar cell necrosis and apoptosis, local and systemic inflammatory response, thereby contributing to the initiation and progression of AP. Moreover, patients with AP possess unique miRNA signatures when compared with healthy individuals or those with other diseases. In view of their stability and easy detection, therefore, miRNAs have the potential to act as biomarkers for the diagnosis and assessment of patients with AP. In this review, we provide an overview of the novel cellular and molecular mechanisms underlying the roles of miRNAs during the disease processes of AP, as well as the potential diagnosis and therapeutic biomarkers of miRNAs in patients with AP.

MicroRNA in Pancreatic Cancer: From Biology to Therapeutic Potential

Pancreatic cancer is one of the most aggressive malignancies, accounting for more than 45,750 deaths annually in the U.S. alone. The aggressive nature and late diagnosis of pancreatic cancer, coupled with the limitations of existing chemotherapy, present the pressing need for the development of novel therapeutic strategies. Recent reports have demonstrated a critical role of microRNAs (miRNAs) in the initiation, progression, and metastasis of cancer. Furthermore, aberrant expressions of miRNAs have often been associated with the cause and consequence of pancreatic cancer, emphasizing the possible use of miRNAs in the effective management of pancreatic cancer patients. In this review, we provide a brief overview of miRNA biogenesis and its role in fundamental cellular process and miRNA studies in pancreatic cancer patients and animal models. Subsequent sections narrate the role of miRNA in, (i) cell cycle and proliferation; (ii) apoptosis; (iii) invasions and metastasis; and (iv) various cellular signaling pathways. We also describe the role of miRNA's in pancreatic cancer; (i) diagnosis; (ii) prognosis and (iii) therapeutic intervention. Conclusion section describes the gist of review with future directions.

Plasma exosome-encapsulated microRNA-21 and microRNA-92a are promising biomarkers for the prediction of peritoneal recurrence in patients with gastric cancer

In patients with gastric cancer (GC), peritoneal recurrence is a common risk and associated with poor prognosis. A novel biomarker for the prediction of high-risk peritoneal recurrence in patients with GC is desirable. The present study investigated the effectiveness of exosome-encapsulated microRNAs (ex-miRNAs) as minimally invasive biomarkers in patients with GC that received curative surgery. Recurrence-specific ex-miRNAs were selected following comparison of miRNA microarray data from patients with TNM stage II GC with peritoneal recurrence (n=3) and without peritoneal recurrence following curative surgery (n=3), and three healthy volunteers. In this analysis, exosome-encapsulated miRNA-21 (ex-miR-21) and exosomal miR-92a (ex-miR-92a) exhibited the greatest alterations in expression patterns. Using plasma exosome samples collected from another 129 patients with stage II and III GC, the present study investigated the potential value of ex-miR-21 and ex-miR-92a as biomarkers. Ex-miRNA levels were measured using TaqMan miRNA assays. Ex-miR-21 levels were significantly higher and ex-miR-92a levels were significantly lower in samples from patients with GC compared with healthy controls. The overall survival (OS) and peritoneal recurrence-free survival (PRFS) were poorer in stage II and III patients with high ex-miR-21 levels than in patients with low miR-21 levels. OS and PRFS of stage II and III patients with low ex-miR92a levels were significantly worse than those with high ex-miR92a levels. Cox multivariate analyses indicated that ex-miR-21 and ex-miR-92a were independent prognostic factors for OS and PRFS in stage II and III GC. A negative correlation was detected between expression levels of miR-21 and programmed cell death protein 4 mRNA, and miR-92a and prostaglandin E receptor 4 mRNA. Therefore, ex-miR-21 and ex-miR-92a may function as effective and minimally invasive biomarkers for the prediction of peritoneal recurrence and the prognosis of patients with stage II/III GC.

Analysis of microRNA expression in brush cytology specimens improves the diagnosis of pancreatobiliary cancer

BACKGROUND/OBJECTIVES

Malignant pancreatobiliary strictures are in many cases clinically indistinguishable and present a major problem to endoscopy specialists. Intraductal sampling procedures such as brush cytology are commonly used for diagnosis with a sensitivity that is low for a diagnostic test used in daily clinical practice. MicroRNA (miR) alterations detected in many cancers are disease-specific, which can be utilized in clinical applications. The aim of the present study was to analyze whether determination of miR expression levels in intraductal brush cytology specimens is a feasible approach to improve the diagnosis of pancreatobiliary cancer.

METHODS

Brush cytology specimens have been collected during endoscopic retrograde cholangio-pancreatography (ERCP) and analyzed by routine cytology and ancillary miR assays. Total RNA was extracted using the miRNeasy Mini Kit and the expression of miRs frequently dysregulated in pancreatobiliary cancer (miR-16, miR-21, miR-196a, miR-221) were analyzed by quantitative real-time PCR using RNU6B as internal control.

RESULTS

Routine cytology resulted in no false positive diagnoses, however, the combined sensitivity remained at 53.8%. Expression (ΔCt values) of miR-16 (p = 0.0039), miR-196a (p = 0.0003) and miR-221 (p = 0.0049) showed a clear statistical significance between malignant and benign pancreatobiliary specimens (n = 35). Malignancy could be detected combining routine cytology and the miR-196a single marker expression levels with a sensitivity of 84.6% (92.9% in biliary strictures) with no false positives.

CONCLUSIONS

The results offer the first direct demonstration that microRNAs are readily detectable in brush cytology specimens obtained during ERCP, and have the potential to help the cytological diagnosis of pancreatobiliary malignancy.

Evaluation of the Relative Performance of Pancreas-Specific MicroRNAs in Rat Plasma as Biomarkers of Pancreas Injury

Drug-induced pancreatic injury (DIPI) has become linked in recent years to many commonly prescribed medications from several pharmacological classes. Diagnosis is currently most often focused on identification of acute pancreatitis and generally based on subjective clinical assessment and serum amylase and lipase enzymatic activity, which have been criticized as being insufficiently sensitive and specific. The lack of novel noninvasive biomarkers of DIPI can impede the advancement of drug candidates through nonclinical development and translation into clinical settings. Pancreas-specific microRNAs (miRNAs) are currently being evaluated as biomarkers of DIPI that may outperform and/or add value to the interpretation of amylase and lipase. To assess the relative performance of these novel miRNAs, a comprehensive evaluation was conducted to determine the sensitivity and specificity of detecting DIPI in rats. Four miRNAs were evaluated (miR-216a-5p, miR-216b-5p, miR-217-5p, and miR-375-3p) in plasma from 10 studies in which rats were treated with known pancreatic toxicants to assess sensitivity, and from 10 different studies in which toxicity was evident in tissues other than pancreas to assess specificity. The candidate miRNA biomarker performance was compared with amylase and lipase, and receiver operator characteristics (ROC) were determined. Analysis of ROCs demonstrated that all four miRNAs outperformed amylase and lipase in monitoring acute pancreatic injury defined as acinar cell degeneration/necrosis. Specifically, miR-217-5p had the highest performance among all biomarkers assessed. The increased sensitivity and specificity of these miRNAs support their use as biomarkers of DIPI, thereby adding value to the interpretation of amylase and lipase measurements in nonclinical studies. The potential for miRNAs to serve as translational biomarkers in the clinic for the monitoring of DIPI is also supported by this investigation.

Knockout of Acinar Enriched microRNAs in Mice Promote Duct Formation But Not Pancreatic Cancer

The pancreatic acinar-enriched miR-216a, miR-216b and miR-217 are encoded within the miR217HG. These miRNAs have been purported to play a tumor suppressive role as their expression is reduced in both human and mouse pancreatic ductal adenocarcinoma (PDAC). To examine this possibility, we generated individual, germline knockout (KO) mice of miR-216a, miR-216b or miR-217. Unlike our previous study showing germline deletion of the miR217HG was embryonic lethal, CRISPR-Cas9 deleted portions of the 5' seed region of the miRNAs produced live births. To investigate possible phenotypes during pancreatic acinar ductal metaplasia (ADM), pancreatic acini from wild type and KO mice were plated on collagen and allowed to transdifferentiate over 4 days. Acini from each of the three miRNA KO mice produced greater numbers of ducts compared to controls. Evaluation of the gene expression during in vitro ADM demonstrated an increase in Krt19 and a reduction in acinar genes (Carboxypeptidase A1, Amylase2a) on day 4 of the transdifferentiation. Recovery was delayed for the miR-216a and miR-216b KOs following caerulein-induced acute pancreatitis. Also predominate in the caerulein treated miR-216a and miR-216b KO mice was the presence of pancreatic duct glands (PDGs). To further establish a phenotype, miRNA KO mice were crossed with EL-KRASG12D (EK) mice and followed up to 13 months of age. While all mice developed severe dysplasia and cystic papillary neoplasms, there existed no apparent phenotypic difference in the miRNA KO/EK mice compared to EK mice. Our data does not support a tumor suppressor role for miR-216a, miR-216b or miR-217 in PDAC and emphasizes the need for phenotypic evaluation of miRNAs in complex in vivo models beyond that performed using cell culture.

Macrophage-derived exosomal microRNA-501-3p promotes progression of pancreatic ductal adenocarcinoma through the TGFBR3-mediated TGF-β signaling pathway

Background

Exosomes from cancer cells or immune cells, carrying bio-macromolecules or microRNAs (miRNAs), participate in tumor pathogenesis and progression by modulating microenvironment. Our study aims to investigate the role of these microRNA-501-3p (miR-501-3p) containing exosomes derived from tumor-associated macrophage (TAM) in the progression of pancreatic ductal adenocarcinoma (PDAC).

Methods

Firstly, the function of TAM recruitment in PDAC tissues was assessed, followed by identification of the effects of M2 macrophage-derived exosomes on PDAC cell activities and tumor formation and metastasis in mice. In silico analysis was conducted to predict differentially expressed genes and regulatory miRNAs related to PDAC treated with macrophages, which determined miR-501-3p and TGFBR3 for subsequent experiments. Next, gain- and loss-of-function experiments were performed to examine their role in PDAC progression with the involvement of the TGF-β signaling pathway.

Results

TAM recruitment in PDAC tissues was associated with metastasis. Highly expressed miR-501-3p was observed in PDAC tissues and TAM-derived exosomes. Both M2 macrophage-derived exosomes and miR-501-3p promoted PDAC cell migration and invasion, as well as tumor formation and metastasis in nude mice. MiR-501-3p was verified to target TGFBR3. PDAC cells presented with down-regulated TGFBR3, which was further decreased in response to M2 macrophage treatment. TGF-β signaling pathway activation was implicated in the promotion of miR-501-3p in PDAC development. The suppression of macrophage-derived exosomal miR-501-3p resulted in the inhibition of tumor formation and metastasis in vivo.

Conclusion

M2 macrophage-derived exosomal miR-501-3p inhibits tumor suppressor TGFBR3 gene and facilitates the development of PDAC by activating the TGF-β signaling pathway, which provides novel targets for the molecular treatment of PDAC.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1313-x) contains supplementary material, which is available to authorized users.

Emerging roles of microRNAs in regulating the mTOR signaling pathway during tumorigenesis

The mammalian target of rapamycin (mTOR) is a large Ser/Thr protein kinase that belongs to the phosphoinositide 3-kinase (PI3K) family and mediates various physiological and pathological processes, especially cell proliferation, protein synthesis, autophagy, and cancer development. The mTOR expression is transient and tightly regulated in normal cells, but it is overactivated in cancer cells. Recently, several studies have indicated that microRNAs (miRNAs) play a critical role in the regulation of mTOR and mTOR-associated processes, some acting as inhibitors and the others as activators. Although it is still in infancy, the strategy of combining both miRNAs and mTOR inhibitors might provide an approach to selectively sensitizing tumor cells to chemotherapy-induced DNA damage and subsequently attenuating the tumor cell growth and apoptosis.

Expression and Role of MicroRNAs from the miR-200 Family in the Tumor Formation and Metastatic Propensity of Pancreatic Cancer

MicroRNAs from the miR-200 family are commonly associated with the inhibition of the metastatic potential of cancer cells, following inhibition of ZEB transcription factors expression and epithelial-to-mesenchymal transition. However, previous studies performed in pancreatic adenocarcinoma revealed a more complex picture challenging this canonical model. To gain better insights into the role of miR-200 family members in this disease, we analyzed the expression of miR-200a, miR-200b, miR-200c, miR-141, miR-429, and miR-205, and ZEB1, ZEB2, and CDH1 in pancreatic tumors and matching normal adjacent parenchyma and patient-derived xenografts. We found that miR-200a, miR-429, and miR-205 are frequently overexpressed in pancreatic tumors, whereas CDH1 is downregulated, and ZEB1 and ZEB2 levels remain unchanged. Furthermore, we measured a positive correlation between miR-200 family members and CDH1 expression, and a negative correlation between ZEB1 and miR-200c, miR-141, and miR-205 expression, respectively. Interestingly, we identified significant changes in expression of epithelial-to-mesenchymal transition regulators and miR-200 members in patient-derived xenografts. Lastly, functional studies revealed that miR-141 and miR-429 inhibit the tumorigenic potential of pancreatic cancer cells. Taken together, this comprehensive analysis strongly suggests that miRNAs from the miR-200 family, and in particular miR-429, may act as a tumor suppressor gene in pancreatic cancer.

Rodrigues MA, Hasimoto CN, Oliveira WK, Pelafsky L, Spadella CT, Llanos JC, F. Silva G, Lam WL, Rogatto SR, Amorim LS, Drigo SA, Carvalho RF, Reis PP. MicroRNA modulated networks of adaptive and innate immune response in pancreatic ductal adenocarcinoma

Despite progress in treatment strategies, only ~24% of pancreatic ductal adenocarcinoma (PDAC) patients survive >1 year. Our goal was to elucidate deregulated pathways modulated by microRNAs (miRNAs) in PDAC and Vater ampulla (AMP) cancers. Global miRNA expression was identified in 19 PDAC, 6 AMP and 25 paired, histologically normal pancreatic tissues using the GeneChip 4.0 miRNA arrays. Computational approaches were used for miRNA target prediction/identification of miRNA-regulated pathways. Target gene expression was validated in 178 pancreatic cancer and 4 pancreatic normal tissues from The Cancer Genome Atlas (TCGA). 20 miRNAs were significantly deregulated (FC≥2 and p<0.05) (15 down- and 5 up-regulated) in PDAC. miR-216 family (miR-216a-3p, miR-216a-5p, miR-216b-3p and miR-216b-5p) was consistently down-regulated in PDAC. miRNA-modulated pathways are associated with innate and adaptive immune system responses in PDAC. AMP cancers showed 8 down- and 1 up-regulated miRNAs (FDR p<0.05). Most enriched pathways (p<0.01) were RAS and Nerve Growth Factor signaling. PDAC and AMP display different global miRNA expression profiles and miRNA regulated networks/tumorigenesis pathways. The immune response was enriched in PDAC, suggesting the existence of immune checkpoint pathways more relevant to PDAC than AMP.

miRNA-143 replacement therapy harnesses the proliferation and migration of colorectal cancer cells in vitro

miR-143 is a tumor suppressor miRNA which its downregulation is frequently reported in colorectal cancer (CRC). This miRNA is a negative regulator of K-RAS, c-MYC, BCL-2, and MMP-9 genes which are engaged in tumor growth and metastasis. In the present study, miR-143 restoration was performed by transfection of the pCMV-miR-143 vector into the SW-480 CRC cells. Subsequently, alterations in proliferative and migratory potential of the cells were investigated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and wound-healing assays, respectively. Moreover, to detect apoptosis incidence in the transfected cells, 4',6-diamidino-2-phenylindole (DAPI) staining was used. Furthermore, mRNA levels of c-MYC, K-RAS, MMP-9, and BCL-2, as potential targets of miR-143, were assessed by quantitative Real-Time PCR (qRT-PCR). Also the expression levels of c-MYC, K-RAS, and MMP-9 proteins were investigated by the western blot analysis. Finally, the ratio of BAX to BCL-2 expression, as a potential marker of the response to apoptosis stimuli, was compared between the control and test groups. Furthermore, the trypan blue test was performed to determine the cell viability in cell suspension. According to the results, a decreased viability and migratory potential was observed for the miR-143 receiving cells. The DAPI staining also confirmed the occurrence of apoptosis. Moreover, BCL-2, K-RAS, MMP-9, and c-MYC mRNAs were significantly downregulated in the miR-143 grafted cells. The BAX/BCL-2 ratio also indicated a notable increase in the cells with miR-143 overexpression. In brief, miR-143 replacement could be considered as an effective strategy for the management of CRC and attenuating its invasive features.

miR-155 expression in antitumor immunity: The higher the better?

MicroRNAs are small noncoding RNAs that modulate gene expression either directly, by impairing the stability and/or translation of transcripts that contain their specific target sequence, or indirectly through the targeting of transcripts that encode transcription factors, factors implicated in signal transduction pathways, or epigenetic regulators. Abnormal expression of micro-RNAs has been found in nearly all types of pathologies, including cancers. MiR-155 has been the first microRNA to be implicated in the regulation of the innate and adaptative immune responses, and its expression is either increased or decreased in a variety of liquid and solid malignancies. In this review, we examine the oncogenic and antitumor potentials of miR-155, with special emphasize on its dose-dependent effects. We describe the impact of miR-155 levels on antitumor activity of lymphocytes and myeloid cells. We discuss miR-155 dose-dependent effects in leukemias and analyze results showing that miR-155 intermediate levels tend to be detrimental, whereas high levels of miR-155 expression usually prove beneficial. We also examine the beneficial effects of high levels of miR-155 expression in solid tumors. We discuss the possible causal involvement of miR-155 in leukemias and dementia in individuals with Down's syndrome. We finally propose that increasing miR-155 levels in immune cells might increase the efficiency of newly developed cancer immunotherapies, due to miR-155 ability to target transcripts encoding immune checkpoints such as cytotoxic T lymphocyte antigen-4 or programmed death-ligand 1.

Plasma Micro-RNA Alterations Appear Late in Pancreatic Cancer

Objectives:

The aim of this research was to study whether plasma microRNAs (miRNA) can be used for early detection of pancreatic cancer (PC) by analyzing prediagnostic plasma samples collected before a PC diagnosis.

Background:

PC has a poor prognosis due to late presenting symptoms and early metastasis. Circulating miRNAs are altered in PC at diagnosis but have not been evaluated in a prediagnostic setting.

Methods:

We first performed an initial screen using a panel of 372 miRNAs in a retrospective case-control cohort that included early-stage PC patients and healthy controls. Significantly altered miRNAs at diagnosis were then measured in an early detection case-control cohort wherein plasma samples in the cases are collected before a PC diagnosis. Carbohydrate antigen 19–9 (Ca 19–9) levels were measured in all samples for comparison.

Results:

Our initial screen, including 23 stage I-II PC cases and 22 controls, revealed 15 candidate miRNAs that were differentially expressed in plasma samples at PC diagnosis. We combined all 15 miRNAs into a multivariate statistical model, which outperformed Ca 19–9 in receiver-operating characteristics analysis. However, none of the candidate miRNAs, individually or in combination, were significantly altered in prediagnostic plasma samples from 67 future PC patients compared with 132 matched controls. In comparison, Ca 19–9 levels were significantly higher in the cases at <5 years before diagnosis.

Conclusion:

Plasma miRNAs are altered in PC patients at diagnosis, but the candidate miRNAs found in this study appear late in the course of the disease and cannot be used for early detection of the disease.

MicroRNA-31 reflects IL-6 expression in cancer tissue and is related with poor prognosis in bile duct cancer

Bile duct cancer is a highly aggressive malignancy wherein early diagnosis is difficult and few treatment options are available. MicroRNA-31 (miR-31) is reported to be related with survival in patients with gastrointestinal cancers; however, the regulatory mechanism of miR-31 and association between miR-31 expression and survival in patients with bile duct cancer cases have not been established. Thus, we evaluated miR-31 expression in bile duct cancer tissues and assessed its relationship with prognosis. Additionally, we examined the effects of several cytokines on miR-31 expression. The study included 81 samples of bile duct cancer tissues. MiR-31 expression in bile duct cancer cells was significantly higher than that in normal bile duct epithelial cells (P = 0.038). There were no significant associations between miR-31 expression and clinical or pathological characteristics, except for tumour size (P = 0.012). In Kaplan-Meier analysis, high miR-31 expression was significantly associated with shorter survival (log-rank test, P = 0.0082). In multivariate Cox regression analysis, high miR-31 expression was significantly associated with prognosis (P = 0.043), independent of clinical or pathological features. Interleukin-6 (IL-6) significantly promoted miR-31 expression and cell proliferation in a dose-dependent manner, and the inhibition of STAT-3 signalling significantly suppressed miR-31 expression and cell proliferation. In conclusion, high expression was significantly associated with poor prognosis in bile duct cancer patients. The IL-6-STAT-3 signalling regulated bile duct cancer cell proliferation and miR-31 expression. Our findings suggest that miR-31 may be a promising biomarker that reflects IL-6 expression in bile duct cancer tissues and predicts poor prognosis.

MiR-29b suppresses proliferation and mobility by targeting SOX12 and DNMT3b in pancreatic cancer

Pancreatic cancer is one of the leading causes of solid carcinoma with the worst survival rate. The reasons for the worst survival rate include the lack of biomarkers for early detection, diagnosis at a late stage, and the limitation of the current therapy. Further study to investigate the underlying molecular mechanism in pancreatic cancer patients is necessary. A previous study showed that the miR-29b expression level is dysregulated, suggesting that it may serve an important function in pancreatic cancer. The CCK8 assay and the colony formation assay were used to detect the proliferation ability of the treated pancreatic cancer cells; a wound-healing assay and a transwell assay were used to test the migration and invasion ability and the interactive action of miR-29b and SOX12 or DNMT3b was examined by a luciferase assay. Cell proliferation, migration, and invasion were attenuated by miR-29b, whereas knockdown of SOX12 and DNMT3b could block SW1990 malignant activity. Further, the double luciferase assay showed that miR-29b can target SOX12 and DNMT3b directly by binding to their 3'-untranslated region. Finally, a rescue experiment was conducted by transfecting miR-29b and SOX12 overexpressed plasmid into cells. Cell proliferation, migration, and invasion inhibition induced by miR-29b were reversed by SOX12 overexpression, and revail of the expression of DNMT3b. MiR-29b suppressed proliferation, migration, and invasion by directly targeting SOX12 and DNMT3b in pancreatic cancer cells, and DNMT3b might be a target gene of SOX12.

miR-148a regulates expression of the transferrin receptor 1 in hepatocellular carcinoma

Transferrin receptor 1 (TFR1) is a transmembrane glycoprotein that allows for transferrin-bound iron uptake in mammalian cells. It is overexpressed in various cancers to satisfy the high iron demand of fast proliferating cells. Here we show that in hepatocellular carcinoma (HCC) TFR1 expression is regulated by miR-148a. Within the TFR1 3′UTR we identified and experimentally validated two evolutionarily conserved miRNA response elements (MREs) for miR-148/152 family members, including miR-148a. Interestingly, analyses of RNA sequencing data from patients with liver hepatocellular carcinoma (LIHC) revealed a significant inverse correlation of TFR1 mRNA levels and miR-148a. In addition, TFR1 mRNA levels were significantly increased in the tumor compared to matched normal healthy tissue, while miR-148a levels are decreased. Functional analysis demonstrated post-transcriptional regulation of TFR1 by miR-148a in HCC cells as well as decreased HCC cell proliferation upon either miR-148a overexpression or TFR1 knockdown. We hypothesize that decreased expression of miR-148a in HCC may elevate transferrin-bound iron uptake, increasing cellular iron levels and cell proliferation.