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

Potent effects of dioscin against pancreatic cancer via miR-149-3P-mediated inhibition of the Akt1 signalling pathway

BACKGROUND AND PURPOSE

The aim of the present study was to investigate the effects and possible underlying mechanisms of dioscin against pancreatic cancer in vitro and in vivo.

EXPERIMENTAL APPROACH

In vitro actions of dioscin on viability of ASPC-1 and PANC-1 cells, and in vivo effects to suppress the tumour growth of cell xenografts in nude mice were assessed. In addition, microRNA microarray analysis determined which microRNAs were affected by dioscin. The mechanisms underlying the actions of dioscin against pancreatic cancer were elucidated in terms of Akt1 and other proteins related to aopoptosis.

KEY RESULTS

Dioscin markedly induced apoptosis and significantly suppressed the tumour growth of ASPC-1 and PANC-1 cell xenografts, in nude mice. Total of 107 microRNAs with differential changes were found, in which miR-149-3P targeted with Akt1 was markedly up-regulated by dioscin. Further studies showed that dioscin significantly down-regulated Akt1 levels, and thus induced cell apoptosis by increasing the levels of Bax, Apaf-1, cleaved caspase-3/9, cleaved PARP, suppressing Bcl-2 levels, and causing cytochrome c release. The effects of an inhibitor of miR-149-3P and of siRNA of testicular Akt1 suggested that dioscin showed excellent activity against pancreatic cancer via miR- 149-3P-mediated inhibition of Akt1 signalling pathway.

CONCLUSIONS AND IMPLICATIONS

Collectively, these findings confirmed the potent effects of dioscin against pancreatic cancer and also provided novel insights into the mechanisms of the compound as a potential candidate for the treatment of pancreatic cancer.

Evaluation of Plasma MicroRNAs as Diagnostic and Prognostic Biomarkers in Pancreatic Adenocarcinoma: miR-196a and miR-210 Could Be Negative and Positive Prognostic Markers, Respectively

Background. Identifying diagnostic and prognostic biomarkers that could be targeted in the therapy of pancreatic cancer is essential. Objective. Investigations were conducted with respect to plasma miRNA (miR-21, miR-210, miR-155, miR-196a, miR-20a, and miR-25) expression and clinicopathologic factors to evaluate the prognostic value of miRNAs in pancreatic ductal adenocarcinoma (PDAC). Methods. Plasma miRNAs were detected by real-time quantitative PCR, and the association with clinicopathologic factors was subsequently performed by univariate and multivariate analyses. Results. Six miRNAs expressed significantly higher in PDAC patients than in normal individuals were identified. Receiver operating characteristic (ROC) curves were constructed. It was evident that miRNA expression associated with PDAC, lymph node metastasis, serosal infiltration, and comprehensive therapy reached significance for overall survival. High miR-196a expression was associated with poor survival (P = 0.001), whereas high miR-210 expression was significantly associated with improved survival (P = 0.003). Multivariate survival analysis indicated that the miR-210 and miR-196a expression signature, lymph node metastasis, and comprehensive therapy were independent factors affecting overall survival. Conclusions. MiRNA expression profile is distinctive in PDAC. Aberrant expression of certain miRNAs was remarkably involved in shaping the overall survival time, which include miR-196a overexpression and decreased miR-210 expression.

Tissue MicroRNA profiles as diagnostic and prognostic biomarkers in patients with resectable pancreatic ductal adenocarcinoma and periampullary cancers

Background

The aim of this study was to validate previously described diagnostic and prognostic microRNA expression profiles in tissue samples from patients with pancreatic cancer and other periampullary cancers.

Methods

Expression of 46 selected microRNAs was studied in formalin-fixed paraffin-embedded tissue from patients with resected pancreatic ductal adenocarcinoma (n = 165), ampullary cancer (n=59), duodenal cancer (n = 6), distal common bile duct cancer (n = 21), and gastric cancer (n = 20); chronic pancreatitis (n = 39); and normal pancreas (n = 35). The microRNAs were analyzed by PCR using the Fluidigm platform.

Results

Twenty-two microRNAs were significantly differently expressed in patients with pancreatic cancer when compared to healthy controls and chronic pancreatitis patients; 17 miRNAs were upregulated (miR-21-5p, −23a-3p, −31-5p, −34c-5p, −93-3p, −135b-3p, −155-5p, −186-5p, −196b-5p, −203, −205-5p, −210, −222-3p, −451, −492, −614, and miR-622) and 5 were downregulated (miR-122-5p, −130b-3p, −216b, −217, and miR-375). MicroRNAs were grouped into diagnostic indices of varying complexity. Ten microRNAs associated with prognosis were identified (let-7 g, miR-29a-5p, −34a-5p, −125a-3p, −146a-5p, −187, −205-5p, −212-3p, −222-5p, and miR-450b-5p). Prognostic indices based on differences in expression of 2 different microRNAs were constructed for pancreatic and ampullary cancer combined and separately (30, 5, and 21 indices).

Conclusion

The study confirms that pancreatic cancer tissue has a microRNA expression profile that is different from that of other periampullary cancers, chronic pancreatitis, and normal pancreas. We identified prognostic microRNAs and microRNA indices that were associated with shorter overall survival in patients with radically resected pancreatic cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s40364-017-0087-6) contains supplementary material, which is available to authorized users.

Circulating exosomes and exosomal microRNAs as biomarkers in gastrointestinal cancer

The most important biological function of exosomes is their possible use as biomarkers in clinical diagnosis. Compared with biomarkers identified in conventional specimens such as serum or urine, exosomal biomarkers provide the highest amount of sensitivity and specificity, which can be attributed to their excellent stability. Exosomes, which harbor different types of proteins, nucleic acids and lipids, are present in almost all bodily fluids. The molecular constituents of exosomes, especially exosomal proteins and microRNAs (miRNAs), are promising as biomarkers in clinical diagnosis. This discovery that exosomes also contain messenger RNAs and miRNAs shows that they could be carriers of genetic information. Although the majority of RNAs found in exosomes are degraded RNA fragments with a length of <200 nucleotides, some full-length RNAs might be present that may affect protein production in the recipient cell. In addition, exosomal miRNAs have been found to be associated with certain diseases. Several studies have pointed out miRNA contents of circulating exosomes that are similar to those of originating cancer cells. In this review, the recent advances in circulating exosomal miRNAs as biomarkers in gastrointestinal cancers are discussed. These studies indicated that miRNAs can be detected in exosomes isolated from body fluids such as saliva, which suggests potential advantages of using exosomal miRNAs as noninvasive novel biomarkers.

New developments in the early diagnosis of pancreatic cancer

Pancreatic cancer is an aggressive carcinoma of the digestive system and radical resection, which is available to very few patients, is the only possibility for cure. Since therapeutic choices are limited at the advanced stage, screening and early diagnostic tools are indispensable for a better prognosis. Areas covered: This review illustrates serologic and imaging examinations, and carbohydrate antigens, microRNAs, methylation biomarkers, molecules in exosomes, ultrasound, computed tomography, magnetic resonance imaging, positron emission tomography and endoscopic retrograde cholangiopancreatography, among other topics. No matter which approach is used, the accuracy of early diagnosis is extremely low. Combining different methods greatly improves the accuracy of early diagnosis. This review was conducted utilizing PubMed with key search words pancreatic cancer, early diagnosis, biomarkers and imaging. Expert commentary: Appropriate combination of biomarkers and imaging technologies will become standard practice in the future. Because the incidence of and mortality from pancreatic cancer is rising, further study of new approaches for the early detection of pancreatic tumors is essential.

The cornerstone K-RAS mutation in pancreatic adenocarcinoma: From cell signaling network, target genes, biological processes to therapeutic targeting

RAS belongs to the super family of small G proteins and plays crucial roles in signal transduction from membrane receptors in the cell. Mutations of K-RAS oncogene lead to an accumulation of GTP-bound proteins that maintains an active conformation. In the pancreatic ductal adenocarcinoma (PDAC), one of the most deadly cancers in occidental countries, mutations of the K-RAS oncogene are nearly systematic (>90%). Moreover, K-RAS mutation is the earliest genetic alteration occurring during pancreatic carcinogenetic sequence. In this review, we discuss the central role of K-RAS mutations and their tremendous diversity of biological properties by the interconnected regulation of signaling pathways (MAPKs, NF-κB, PI3K, Ral…). In pancreatic ductal adenocarcinoma, transcriptome analysis and preclinical animal models showed that K-RAS mutation alters biological behavior of PDAC cells (promoting proliferation, migration and invasion, evading growth suppressors, regulating mucin pattern, and miRNA expression). K-RAS also impacts tumor microenvironment and PDAC metabolism reprogramming. Finally we discuss therapeutic targeting strategies of K-RAS that have been developed without significant clinical success so far. As K-RAS is considered as the undruggable target, targeting its multiple effectors and target genes should be considered as potential alternatives.

High Throughput Sequencing of Extracellular RNA from Human Plasma

The presence and relative stability of extracellular RNAs (exRNAs) in biofluids has led to an emerging recognition of their promise as ‘liquid biopsies’ for diseases. Most prior studies on discovery of exRNAs as disease-specific biomarkers have focused on microRNAs (miRNAs) using technologies such as qRT-PCR and microarrays. The recent application of next-generation sequencing to discovery of exRNA biomarkers has revealed the presence of potential novel miRNAs as well as other RNA species such as tRNAs, snoRNAs, piRNAs and lncRNAs in biofluids. At the same time, the use of RNA sequencing for biofluids poses unique challenges, including low amounts of input RNAs, the presence of exRNAs in different compartments with varying degrees of vulnerability to isolation techniques, and the high abundance of specific RNA species (thereby limiting the sensitivity of detection of less abundant species). Moreover, discovery in human diseases often relies on archival biospecimens of varying age and limiting amounts of samples. In this study, we have tested RNA isolation methods to optimize profiling exRNAs by RNA sequencing in individuals without any known diseases. Our findings are consistent with other recent studies that detect microRNAs and ribosomal RNAs as the major exRNA species in plasma. Similar to other recent studies, we found that the landscape of biofluid microRNA transcriptome is dominated by several abundant microRNAs that appear to comprise conserved extracellular miRNAs. There is reasonable correlation of sets of conserved miRNAs across biological replicates, and even across other data sets obtained at different investigative sites. Conversely, the detection of less abundant miRNAs is far more dependent on the exact methodology of RNA isolation and profiling. This study highlights the challenges in detecting and quantifying less abundant plasma miRNAs in health and disease using RNA sequencing platforms.

The Evolving Role of Pathology in New Developments, Classification, Terminology, and Diagnosis of Pancreatobiliary Neoplasms

Pancreatobiliary tract lesions are increasingly being discovered because of more sensitive imaging modalities. Magnetic resonance imaging has identified incidental pancreatic cysts in 13.5% of patients of progressively increasing age. Pancreatobiliary tissue is more accessible through endoscopic ultrasound and magnetic resonance imaging-guided biopsy procedures, and is now an integral part of pathologists' routine practice. Accordingly, several new tumor categories have been recently recognized, including intraductal tubulopapillary neoplasm, a new addition to tumoral intraepithelial neoplasms. Other entities have been reclassified, including the recent transition to 2-tiered grading of preinvasive neoplasms, as well as new perspectives on the distinctive biologic behavior of oncocytic intraductal papillary mucinous neoplasms (IPMNs) compared with other IPMN subtypes. This has led to proposals for revised staging of virtually every segment of the pancreatobiliary tree, with theranostic markers becoming an integral part of workup. Ki-67 is now an integral part of the classification of neuroendocrine tumors, with new definitions of "high-grade neuroendocrine carcinoma." Although bile duct brushings have opened new avenues for diagnosis, their sensitivity remains low and often requires concomitant fluorescent in situ hybridization to better define ambiguous cases. Various molecular pathways have been elucidated for pancreatic cysts, including KRAS for ductal neoplasia, GNAS for intestinal IPMNs, RNF3 for mucinous cysts, and VHL for serous cystic neoplasms, all key players in diagnostic workup. Integration of these updates into our understanding of pancreatobiliary disease requires active engagement of pathologists for appropriate specimen triage, judicious interpretation of results, and incorporation into reporting and staging. They also provide exciting opportunities for targeted therapy.

hsa-miR-96 and hsa-miR-217 Expression Down-Regulates with Increasing Dysplasia in Pancreatic Intraepithelial Neoplasias and Intraductal Papillary Mucinous Neoplasms

AIM: To compare the clinicopathological features of pancreatic intraepithelial neoplasias (PanINs) and intraductal papillary mucinous neoplasms (IPMNs), and to investigate the role of hsa-miR-96 and hsa-miR-217 in these two lesions. Methods: Formalin-fixed paraffin-embedded pancreatic specimens were selected in this study, including 58 cases of pancreatic intraepithelial neoplasias (PanINs), 45 cases of pancreatic ductal adenocarcinomas (PDAs), and 57 cases of intraductal papillary mucinous neoplasms (IPMNs). MiRNAs hsa-miR-96 and hsa-miR-217 were detected using locked nucleic acid in situ hybridization (LNA-ISH) with the NBT/BCIP staining system. The differences in miRNA expression among sample sets were analyzed with the Chi-squared test. Results: PanIN-PDAs were inclined to present with higher rate of invasion (p=0.033), lymph node metastasis (p=0.0004) and poorer differentiation (p<0.001). Of the 45 PDAs, only 2 cases were within AJCC Ⅰstage, while there were 11 cases of IPMN associated carcinomas (p=0.0018). In PanIN-1, PanIN-2 and PanIN-3, the expression of hsa-miR-96 was 91.3% (22/23), 78.6%(12/17) and 22.2%(4/18) respectively, while the expression of hsa-miR-217 was 95.7%(22/23) , 70.6% (12/17) and 27.8% (5/18). In IPMN with low-grade, intermediate-grade, high-grade dysplasia, associated carcinoma, the expression of hsa-miR-96 was 67%(9/13), 64%(7/11), 43%(3/7) and 27%(7/26) respectively, while the expression of hsa-miR-217 was 77%(10/13), 64%(7/11), 29%(2/7) and 38%(10/26). The expression of hsa-miR-96 and hsa-miR-217 in PanIN-1 lesions was not significantly different from that in the normal pancreatic ductal epithelium. However, their expression in PanIN-2/3 lesions was significantly different from that in normal pancreatic ductal epithelium (P<0.01). No difference was observed between PanIN derived adenocarcinomas and IPMN-associated carcinomas. Conclusion: IPMN associated carcinomas were in a statistically earlier stage than PanIN- PDAs at the time of operation. Abnormal expression of hsa-miR-96 and of hsa-miR-217 was observed in premalignant lesions (PanINs and IPMNs) of pancreatic carcinoma and down-regulated with increasing grades of PanINs and IPMNs. These microRNAs may serve as potentially early biomarker and act as tumor suppressor genes.

Circulating microRNA 216 as a Marker for the Early Identification of Severe Acute Pancreatitis

BACKGROUND

To study the value of circulating microRNA 216 (miR-216) as a marker for the severity of acute pancreatitis (AP) in both murine models and patients.

MATERIALS AND METHODS

Mice with AP were induced by intraperitoneal injection of 50μg/kg/hour cerulean either 7 times, sacrificed at 8, 9, 10, 11 or 12 hours after the first injection, or 12 times, sacrificed at 24 hours after the first injection. Plasma samples and data from patients with AP were obtained from a prospective cohort. Quantitative reverse transcription polymerase chain reaction was used to determine the miR-216a and miR-216b level.

RESULTS

The upregulation of miR-216a and miR-216b in the serum of mice was induced by cerulean injection in both the 7- and 12-injection groups (P < 0.05). The downregulation of miR-216a in pancreatic tissues of mice with AP was detected (P < 0.05), but no difference was observed in pancreatic miR-216b levels among any of the groups (all P > 0.05). The serum miR-216a level was positively correlated with pancreatic histopathology severity scores, and was negatively correlated with pancreatic miR-216a (r = -0.483, P = 0.009). The plasma miR-216a level was significantly upregulated in patients with severe AP (SAP) compared with patients with mild AP (MAP) or moderate severe AP (MSAP) (SAP versus MAP, P = 0.04; SAP versus MSAP, P = 0.00), but no difference was seen between patients with MAP and those with MSAP (P = 0.73).

CONCLUSIONS

Circulating miR-216a might be a potential biomarker for the early identification of SAP.

Evaluation of miR-216a and miR-217 as Potential Biomarkers of Acute Exocrine Pancreatic Toxicity in Rats

Detecting and monitoring exocrine pancreatic damage during nonclinical and clinical testing is challenging because classical biomarkers amylase and lipase have limited sensitivity and specificity. Novel biomarkers for drug-induced pancreatic injury are needed to improve safety assessment and reduce late-stage attrition rates. In a series of studies, miR-216a and miR-217 were evaluated as potential biomarkers of acute exocrine pancreatic toxicity in rats. Our results revealed that miR-216a and miR-217 were almost exclusively expressed in rat pancreas and that circulating miR-216a and miR-217 were significantly increased in rats following administration of established exocrine pancreatic toxicants caerulein (CL) and 1-cyano-2-hydroxy-3-butene (CHB) as well as in rats administered a proprietary molecule known to primarily affect the exocrine pancreas. Conversely, neither microRNA was increased in rats administered a proprietary molecule known to cause a lesion at the pancreatic endocrine–exocrine interface (EEI) or in rats administered an established renal toxicant. Compared with amylase and lipase, increases in miR-216a and miR-217 were of greater magnitude, persisted longer, and/or correlated better with microscopic findings within the exocrine pancreas. Our findings demonstrate that in rats, miR-216a and miR-217 are sensitive and specific biomarkers of acute exocrine pancreatic toxicity that may add value to the measurement of classical pancreatic biomarkers.

Cancer-derived exosomic microRNAs shape the immune system within the tumor microenvironment: State of the art

In recent years there has been an increasing interest of the scientific community on exosome research, with particular emphasis on the mechanisms by which tumor-derived exosomes can promote tumor growth. Particularly, exosome-mediated immune-escape is under deep investigation and still represents a quite controversial issue. Tumor-derived exosomes are carriers of information able to reprogram functions of immune target cells, influencing their development, maturation, and antitumor activities. They deliver proteins similar to those of the parent cancer cells, but also genetic messages like genomic DNA, mRNA, and microRNAs (miRNAs) that ultimately share the so called "tumor microenvironment" in a pro-tumoral fashion. The content of tumor-derived exosomes could be implicated in several signaling pathways operating in the tumor microenvironment, providing a further modality of dys-regulation of antitumor immunity. The aim of this review is to provide a state-of-the-art highlight of to the most recent discoveries in the field of interaction between tumor-derived exosomic miRNAs and the cells of immune system.

Early detection of pancreatic cancer: impact of high-resolution imaging methods and biomarkers

High-resolution imaging methods (HRIMs) and biomarkers present the second step of pancreatic cancer (PC) diagnostics in at-risk individuals. These include patients with positive risk factors, early symptoms, nonresponders to the initial antidiabetic therapy, patients older than 50 years of age with new-onset unstable diabetes requiring insulin as well as patients with long-term insulin-non-dependent diabetes and recent (up to 6 months) failure of antidiabetic therapy. The procedures should be started without delay and the co-operation between the primary and tertiary medical centers is highly desirable. An early indication of HRIMs and biomarkers is a prerequisite for the diagnosis of a resectable PC. This publication reviews the recent contribution of HRIMs and biomarkers toward an early diagnosis of PC.

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.

Comprehensive analysis of microRNA signature of mouse pancreatic acini: overexpression of miR-21-3p in acute pancreatitis

In the current study, we have characterized the global miRNA expression profile in mouse pancreatic acinar cells and during acute pancreatitis using next-generation RNA sequencing. We identified 324 known and six novel miRNAs that are expressed in mouse pancreatic acinar cells. In the basal state, miR-148a-3p, miR-375-3p, miR-217-5p, and miR-200a-3p were among the most abundantly expressed, whereas miR-24-5p and miR-421-3p were the least abundant. Treatment of acinar cells with caerulein (100 nM) and taurolithocholic acid 3-sulfate [TLC-S (250 μM)] induced numerous changes in miRNA expression profile. In particular, we found significant overexpression of miR-21-3p in acini treated with caerulein and TLC-S. We further looked at the expression of miR-21-3p in caerulein, l-arginine, and caerulein + LPS-induced acute pancreatitis mouse models and found 12-, 21-, and 50-fold increased expression in the pancreas, respectively. In summary, this is the first comprehensive analysis of global miRNA expression profile of mouse pancreatic acinar cells in normal and disease conditions. Our analysis shows that miR-21-3p expression level correlates with the severity of the disease.

MiRNA-138-5p inhibits proliferation of pancreatic cancer cells

AIM

To investigate the effect of microRNA-138-5p (miR-138-5p) on the proliferation of pancreatic cancer (PC) cells.

METHODS

We constructed lentiviral vectors for miR-138-5p overexpression or knockdown and a negative control lentiviral vector, and transfected them into human PC cell lines PANC-1 and Capan-2. Cell counting kit-8 assay (CCK-8), colony-forming assay and EdU incorporation assay were employed to detect cell proliferation in vitro. The PANC-1 and Capan-2 cells were implanted subcutaneously in Balb/c nude mice to detect cell proliferation in vivo.

RESULTS

Lentiviral vectors were successfully constructed and transfected. CCK-8 assay, colony-forming assay and EdU incorporation assay showed that overexpression of miR-138-5p inhibited cell proliferation compared with the negative control (P < 0.05), while miR-138-5p knockdown promoted cell proliferation compared with the negative control (P < 0.05). In addition, miR-138-5p suppressed tumor growth in the subcutaneous xenograft model of human PC cells in Balb/c nude mice.

CONCLUSION

Our results indicate that miR-138-5p inhibits the proliferation of PC cells, suggesting a potential new therapeutic agent for PC.

A Meta-Analysis: Identification of Common Mir-145 Target Genes that have Similar Behavior in Different GEO Datasets

BACKGROUND

MicroRNAs, which are small regulatory RNAs, post-transcriptionally regulate gene expression by binding 3'-UTR of their mRNA targets. Their deregulation has been shown to cause increased proliferation, migration, invasion, and apoptosis. miR-145, an important tumor supressor microRNA, has shown to be downregulated in many cancer types and has crucial roles in tumor initiation, progression, metastasis, invasion, recurrence, and chemo-radioresistance. Our aim is to investigate potential common target genes of miR-145, and to help understanding the underlying molecular pathways of tumor pathogenesis in association with those common target genes.

METHODS

Eight published microarray datasets, where targets of mir-145 were investigated in cell lines upon mir-145 over expression, were included into this study for meta-analysis. Inter group variabilities were assessed by box-plot analysis. Microarray datasets were analyzed using GEOquery package in Bioconducter 3.2 with R version 3.2.2 and two-way Hierarchical Clustering was used for gene expression data analysis.

RESULTS

Meta-analysis of different GEO datasets showed that UNG, FUCA2, DERA, GMFB, TF, and SNX2 were commonly downregulated genes, whereas MYL9 and TAGLN were found to be commonly upregulated upon mir-145 over expression in prostate, breast, esophageal, bladder cancer, and head and neck squamous cell carcinoma. Biological process, molecular function, and pathway analysis of these potential targets of mir-145 through functional enrichments in PPI network demonstrated that those genes are significantly involved in telomere maintenance, DNA binding and repair mechanisms.

CONCLUSION

As a conclusion, our results indicated that mir-145, through targeting its common potential targets, may significantly contribute to tumor pathogenesis in distinct cancer types and might serve as an important target for cancer therapy.

Changes in microRNA (miRNA) expression during pancreatic cancer development and progression in a genetically engineered KrasG12D;Pdx1-Cre mouse (KC) model

Differential expression of microRNAs (miRNAs) has been demonstrated in various cancers, including pancreatic cancer (PC). Due to the lack of tissue samples from early-stages of PC, the stage-specific alteration of miRNAs during PC initiation and progression is largely unknown. In this study, we investigated the global miRNA expression profile and their processing machinery during PC progression using the Kras^G12D;Pdx1-Cre (KC) mouse model. At 25 weeks, the miRNA microarray analysis revealed significant downregulation of miR-150, miR-494, miR-138, miR-148a, miR-216a, and miR-217 and upregulation of miR-146b, miR-205, miR-31, miR-192, and miR-21 in KC mice compared to controls. Further, expression of miRNA biosynthetic machinery including Dicer, Exportin-5, TRKRA, and TARBP2 were downregulated, while DGCR8 and Ago2 were upregulated in KC mice. In addition, from 10 to 50 weeks of age, stage-specific expression profiling of miRNA in KC mice revealed downregulation of miR-216, miR-217, miR-100, miR-345, miR-141, miR-483-3p, miR-26b, miR-150, miR-195, Let-7b and Let-96 and upregulation of miR-21, miR-205, miR-146b, miR-34c, miR-1273, miR-223 and miR-195 compared to control mice. Interestingly, the differential expression of miRNA in mice also corroborated with the miRNA expression in human PC cell lines and tissue samples; ectopic expression of Let-7b in CD18/HPAF and Capan1 cells resulted in downregulation of KRAS and MSST1 expression. Overall, the present study aids an understanding of miRNA expression patterns during PC pathogenesis and helps to facilitate the identification of promising and novel early diagnostic/prognostic markers and therapeutic targets.

Post-transcriptional Regulation of BRCA2 through Interactions with miR-19a and miR-19b

Breast cancer type 2, early onset susceptibility gene (BRCA2) is a major component of the homologous recombination DNA repair pathway. It acts as a tumor suppressor whose function is often lost in cancers. Patients with specific mutations in the BRCA2 gene often display discrete clinical, histopathological, and molecular features. However, a subset of sporadic cancers has wild type BRCA2 and display defects in the homology-directed repair pathway, which is the hallmark of ‘BRCAness.’ The mechanisms by which BRCAness arises are not well understood but post-transcriptional regulation of BRCA2 gene expression by microRNAs (miRNAs) may contribute to this phenotype. Here, we examine the post-transcriptional effects that some members of the six-miRNA cluster known as the miR-17/92 cluster have on the abundance of BRCA2’s messenger RNA (mRNA) and protein. We discuss two interactions involving the miR-19a and miR-19b members of the cluster and the 3′UTR of BRCA2’s mRNA. We investigated these miRNA:mRNA interactions in 15 cell lines derived from pancreatic, breast, colon, and kidney tissue. We show that over-expression of these two miRNAs results in a concomitant decrease of BRCA2’s mRNA and protein expression in a subset of the tested cell lines. Additionally, using luciferase reporter assays we identified direct interactions between miR-19a/miR-19b and a miRNA response element (MRE) in BRCA2’s 3′UTR. Our results suggest that BRCA2 is subject to a complex post-transcriptional regulatory program that has specific dependencies on the genetic and phenotypic background of cell types.

miR-216 and miR-217 expression is reduced in transgenic mouse models of pancreatic adenocarcinoma, knockout of miR-216/miR-217 host gene is embryonic lethal

Mice harboring a G12D activating Kras mutation are among the most heavily studied models in the field of pancreatic adenocarcinoma (PDAC) research. miRNAs are differentially expressed in PDAC from patients and mouse models of PDAC. To better understand the relationship that Kras activation has on miRNA expression, we profiled the expression of 629 miRNAs in RNA isolated from the pancreas of control, young, and old P48^+/Cre;LSL-KRAS^G12D as well as PDX-1-Cre;LSL-KRAS^G12D mice. One hundred of the differentially expressed miRNAs had increased expression in the advanced disease (old) P48^+/Cre;LSL-KRAS^G12D compared to wild-type mice. Interestingly, the expression of three miRNAs, miR-216a, miR-216b, and miR-217, located within a ∼30-kbp region on 11qA3.3, decreased with age (and phenotype severity) in these mice. miR-216/-217 expression was also evaluated in another acinar-specific ELa-Kras^G12D mouse model and was downregulated as well. As miR-216/-217 are acinar enriched, reduced in human PDAC and target KRAS, we hypothesized that they may maintain acinar differentiation or represent tumor suppressive miRNAs. To test this hypothesis, we deleted a 27.9-kbp region of 11qA3.3 containing the miR-216/-217 host gene in the mouse's germ line. We report that germ line deletion of this cluster is embryonic lethal in the mouse. We estimate that lethality occurs shortly after E9.5. qPCR analysis of the miR-216b and miR-217 expression in the heterozygous animals showed no difference in expression, suggesting haplosufficiency by some type of compensatory mechanism. We present the differential miRNA expression in Kras^G12D transgenic mice and report lethality from deletion of the miR-216/-217 host gene in the mouse's germ line.

The potential diagnostic value of serum microRNA signature in patients with pancreatic cancer

Biomarkers for early diagnosis of patients with pancreatic cancer (PC) are needed. Our aim was to identify panels of miRNAs in serum in combination with CA 19-9 for use in the diagnosis of PC. Four hundred seventeen patients with PC were included prospectively from Denmark (n = 306) and Germany (n = 111). Controls included 59 patients with chronic pancreatitis (CP) and 248 healthy subjects (HS). MiRNAs were analyzed in pretreatment serum samples from 3 cohorts: discovery cohort (754 human miRNAs, TaqMan(®) Human MicroRNA assay, Applied Biosystem; PC n = 133, controls n = 72); training cohort (34 miRNAs, real-time qPCR using the Fluidigm BioMark™ System; PC n = 198, controls n = 184); validation cohort (13 miRNAs, real-time qPCR using the Fluidigm BioMark™ System; PC n = 86, controls n = 51). We found that 34 miRNAs in serum from PC patients in the discovery cohort were expressed differently than in controls. These miRNAs were tested in the training cohort, and four diagnostic panels were constructed that included 5 or 12 miRNAs (miR-16, -18a, -20a, -24, -25, -27a, -29c, -30a.5p, -191, -323.3p, -345 and -483.5p). Diagnostic accuracy of detecting PC in the training cohort was AUC (Index I 0.85; II 0.87; III 0.85; IV 0.95; CA 19-9 0.93); specificity (I 0.71; II 0.76; III 0.66; IV 0.90 (fixed sensitivity at 0.85); CA 19-9 0.93). Combining serum CA 19-9 and Index II best discriminated Stages I and II PC from HS [AUC 0.93 (0.90-0.96), sensitivity 0.77 (0.69-0.84), specificity 0.94 (0.90-0.96) and accuracy 0.88 (0.84-0.91)]. In conclusion, we identified four diagnostic panels based on 5 or 12 miRNAs in serum that could distinguish patients with PC from HS and CP.

Specific MAPK-Associated MicroRNAs in Serum Differentiate Pancreatic Cancer from Autoimmune Pancreatitis

Pancreatic ductal adenocarcinoma (PDAC) is difficult to distinguish from autoimmune pancreatitis (AIP) because of their clinical and radiological similarities, and therefore simple and minimally invasive surrogate markers for differential diagnosis would be useful. In our previous studies, we identified four microRNAs (miRNAs)–miR-7, miR-34a, miR-181d, and miR-193b –as MAPK-associated microRNAs whose expression was altered significantly with upregulation of the MAPK signaling pathway. Recently it has been reported that these miRNAs could be used as biomarkers in serum samples for accurate diagnosis of pancreatic lesions. The aim of the present study was to evaluate whether these MAPK-associated miRNAs in serum could be used as biomarkers for differentiating PDAC from AIP. We enrolled 69 patients with PDAC, 26 with intraductal papillary mucinous neoplasm (IPMN) and 15 with AIP. The expression of MAPK-associated miRNAs in serum was measured by quantitative real-time PCR. The 2^-ΔCT method was used to quantify the expression of miRNAs, and the data were normalized using spiked-in synthetic cel-miR-39. Patients with PDAC or IPMN showed significantly higher amounts of serum MAPK-associated miRNAs than those with AIP (p<0.009 for miR-7, p<0.002 for miR-34a, p<0.001 for miR-181d, p<0.002 for miR-193b). ROC curve analysis demonstrated that these miRNAs had an area under the ROC curve (AUC) of 0.723–0.882 for differentiation between PDAC or IPMN from AIP. Furthermore, serum miR-181d was significantly associated with the presence of metastasis in patients with PDA (p = 0.014). Serum MAPK-associated miRNAs could be novel noninvasive biomarkers for differentiation between PDAC or IPMN and AIP.

The promise of epigenomic therapeutics in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is often viewed to arise primarily by genetic alterations. However, today we know that many aspects of the cancer phenotype require a crosstalk among these genetic alterations with epigenetic changes. Indeed, aberrant gene expression patterns, driven by epigenetics are fixed by altered signaling from mutated oncogenes and tumor suppressors to define the PDAC phenotype. This conceptual framework may have significant mechanistic value and could offer novel possibilities for treating patients affected with PDAC. In fact, extensive investigations are leading to the development of small molecule drugs that reversibly modify the epigenome. These new ‘epigenetic therapeutics’ discussed herein are promising to fuel a new era of studies, by providing the medical community with new tools to treat this dismal disease.

The Role of Mir-148a in Cancer

MicroRNAs (miRNAs) are highly conserved noncoding RNAs of about 19-25 nucleotides. Through specifically pairing with complementary sites in 3' untranslated regions (UTRs) of target mRNAs, they mediate post-transcriptional silencing. MicroRNAs have been implicated in many physiological processes including proliferation, differentiation, development, apoptosis, and metabolism. In recent years many studies have revealed that the aberrant expression of miRNA is closely related to oncogenesis and is now an intense field of study. Mir-148a is aberrantly expressed in various cancers and has been identified as an oncogenic or tumor suppressor with crucial roles in the molecular mechanisms of oncogenesis. In this review, we have summarized the role of mir-148a in the oncogenic pathways of gastric, liver, breast and urogenital cancers, and in neurogliocytoma oncogenesis. Studying the functional role of mir-148a is crucial in discovering novel tumor molecular markers and identifying potential therapeutic targets.

The Role of microRNAs in the Diagnosis and Treatment of Pancreatic Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a very challenging malignancy. Disease is diagnosed in an advanced stage in the vast majority of patients, and PDAC cells are often resistant to conventional cytotoxic drugs. Targeted therapies have made no progress in the management of this disease, unlike other cancers. microRNAs (miRs) are small non-coding RNAs that regulate the expression of multitude number of genes by targeting their 3'-UTR mRNA region. Aberrant expression of miRNAs has been linked to the development of various malignancies, including PDAC. In PDAC, a series of miRs have been defined as holding promise for early diagnostics, as indicators of therapy resistance, and even as markers for therapeutic response in patients. In this mini-review, we present an update on the various different miRs that have been defined in PDAC biology.

Endogenous and tumour-derived microRNAs regulate cross-presentation in dendritic cells and consequently cytotoxic T cell function

Dendritic cells (DCs) are potent antigen presenting cells (APCs). They are also specialized in the induction of cytotoxic T lymphocyte mediated responses against extracellular antigens, including tumour-specific antigens, by presenting peptide-Major Histocompatibility Complex (MHC) I complexes to naïve CD8⁺ T cells in lymphoid tissues, a process called cross-presentation. Emerging evidence suggests that the efficiency of cross-presentation can be influenced by a unique set of microRNAs (miRNAs). Some are differentially expressed in the course of morphological and functional development of DCs while tumorigenic miRNAs (onco-miRs) can be delivered to and inserted into DCs via exosomes. The latter reprogram the miRNA repertoire of DCs, transforming them from effective APCs to negative modulators of immunity, ultimately aiding cancers to evade host immunity. On the other hand, endogenous microRNAs can influence cross-presentation either positively or negatively. In this review, we discuss the possible mechanisms by which specific miRNAs influence cross-presentation as well as the viability of manipulating the expression of miRNAs that regulate DC cross-presentation as a potential cancer immunotherapy intervention.

Phenethyl isothiocyanate (PEITC) suppresses prostate cancer cell invasion epigenetically through regulating microRNA-194

SCOPE

Tumor metastasis greatly contributes to the mortality of prostate cancer. The glucosinolate-derived phenethyl isothiocyanate (PEITC) has been widely documented to reduce the risk of prostate cancer by modulating multiple biologically relevant processes. Emerging evidence suggests that PEITC may exert its anti-cancer effects through epigenetic mechanisms including microRNAs. Altered levels of miRNA have been linked to tumor malignancy due to their capacity to regulate functional gene expression in carcinogenesis. Here, we assessed the effects of PEITC on miRNA expression which is related to PCa cell invasiveness.

METHODS AND RESULTS

Utilizing oligonucleotide microarray first identified the most affected miRNAs in LNCaP cells after PEITC treatment. Several top altered miRNAs were further validated using quantitative PCR. Interestingly, overexpression of miR-194 suppressed PC3 cell invasion in matrigel-coated Transwell chambers. Bone morphogenetic protein 1 (BMP1) was shown to be a direct target of miR-194. Downregulation of BMP1 by miR-194 or PEITC led to decreased expression of key oncogenic matrix metalloproteinases, MMP2 and MMP9. This in turn resulted in the suppression of tumor invasion.

CONCLUSION

Our results indicate that miR-194 downregulates the expression of oncogenic MMP2 and MMP9 by targeting BMP1, which suggests a potential new mechanistic target by which PEITC suppresses prostate cancer cell invasiveness.

Managing Pancreatic Adenocarcinoma: A Special Focus in MicroRNA Gene Therapy

Pancreatic cancer is an aggressive disease and the fourth most lethal cancer in developed countries. Despite all progress in medicine and in understanding the molecular mechanisms of carcinogenesis, pancreatic cancer still has a poor prognosis, the median survival after diagnosis being around 3 to 6 months and the survival rate of 5 years being less than 4%. For pancreatic ductal adenocarcinoma (PDAC), which represents more than 90% of new pancreatic cancer cases, the prognosis is worse than for the other cancers with a patient mortality of approximately 99%. Therefore, there is a pressing need for developing new and efficient therapeutic strategies for pancreatic cancer. In this regard, microRNAs not only have been seen as potential diagnostic and prognostic molecular markers but also as promising therapeutic agents. In this context, this review provides an examination of the most frequently deregulated microRNAs (miRNAs) in PDAC and their putative molecular targets involved in the signaling pathways of pancreatic
carcinogenesis. Additionally, it is presented a summary of gene therapy clinical trials involving miRNAs and it is illustrated the therapeutic potential associated to these small non-coding RNAs, for PDAC treatment. The facts presented here constitute a strong evidence of the remarkable opportunity associated to the application of microRNA-based therapeutic strategies as a novel approach for cancer therapy.

Expression and Function of miR-155 in Diseases of the Gastrointestinal Tract

MicroRNAs (miRNAs) are a type of small noncoding RNA that can regulate the expression of target genes under physiological and pathophysiological conditions. miR-155 is a multifunctional miRNA with inflammation-related and oncogenic roles. In particular, the dysregulation of miR-155 has been strongly implicated in Helicobacter pylori-related gastric disease, inflammatory bowel disease, and colorectal cancer in addition to being involved in molecular changes of important targets and signaling pathways. This review focuses on the expression and function of miR-155 during inflammation and carcinogenesis and its potential use as an effective therapeutic target for certain gastrointestinal diseases.

Prospective validation of microRNA signatures for detecting pancreatic malignant transformation in endoscopic-ultrasound guided fine-needle aspiration biopsies

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease. Novel biomarkers are required to aid treatment decisions and improve patient outcomes. MicroRNAs (miRNAs) are potentially ideal diagnostic biomarkers, as they are stable molecules, and tumour and tissue specific.

RESULTS

Logistic regression analysis revealed an endoscopic-ultrasound fine-needle aspiration (EUS-FNA) 2-miRNA classifier (miR-21 + miR-155) capable of distinguishing benign from malignant pancreatic lesions with a sensitivity of 81.5% and a specificity of 85.7% (AUC 0.930). Validation FNA cohorts confirmed both miRNAs were overexpressed in malignant disease, while circulating miRNAs performed poorly.

METHODS

Fifty-five patients with a suspicious pancreatic lesion on cross-sectional imaging were evaluated by EUS-FNA. At echo-endoscopy, the first part of the FNA was sent for cytological assessment and the second part was used for total RNA extraction. Candidate miRNAs were selected after careful review of the literature and expression was quantified by qRT-PCR. Validation was performed on an independent cohort of EUS-FNAs, as well as formalin-fixed paraffin embedded (FFPE) and plasma samples.

CONCLUSIONS

We provide further evidence for using miRNAs as diagnostic biomarkers for pancreatic malignancy. We demonstrate the feasibility of using fresh EUS-FNAs to establish miRNA-based signatures unique to pancreatic malignant transformation and the potential to enhance risk stratification and selection for surgery.

Altered profile of serum microRNAs in pancreatic cancer-associated new-onset diabetes mellitus

BACKGROUND

New-onset diabetes mellitus in pancreatic cancer has been recognized as a paraneoplastic phenomenon caused by the existence of the tumor. Circulating microRNAs (miRNAs) are emerging as non-invasive biomarkers for the detection of various cancers. In the present study, we hypothesized that a specific serum miRNA profile exists in pancreatic cancer-associated new-onset diabetes mellitus (PaC-DM).

METHODS

Initial screening of differentially expressed miRNAs in pooled serum samples from 25 PaC-DM patients, 25 non-cancer new-onset type 2 diabetes mellitus (T2DM) patients, and 25 healthy controls was performed by TaqMan low-density arrays (TLDA). A stem-loop quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was conducted to confirm the relative concentrations of candidate miRNAs in 80 PaC-DM, 85 non-cancer new-onset T2DM patients, and 80 healthy controls.

RESULTS

The TLDA identified 16 serum miRNAs that were significantly increased in PaC-DM samples. A combination of six serum miRNAs (miR-483-5p, miR-19a, miR-29a, miR-20a, miR-24, miR-25) was selected by qRT-PCR as a biomarker for PaC-DM. The area under the receiver operating characteristic curve (AUC) for the six-miRNA panel training and validation sets was 0.959 (95% confidence interval [CI] 0.890-1.028) and 0.902 (95% CI 0.844-0.955), respectively. The combination of these six miRNAs enabled the discrimination of PaC-DM from non-cancer new-onset T2DM with an AUC of 0.885 (95% CI 0.784-0.986) and 0.887 (95% CI 0.823-0.952) for the training and validation sets, respectively.

CONCLUSION

The six-serum miRNA panel may have potential as a biomarker for the accurate diagnosis and discrimination of PaC-DM from healthy controls and non-cancer new-onset T2DM.

Ratiometric Array of Conjugated Polymers-Fluorescent Protein Provides a Robust Mammalian Cell Sensor

Supramolecular complexes of a family of positively charged conjugated polymers (CPs) and green fluorescent protein (GFP) create a fluorescence resonance energy transfer (FRET)-based ratiometric biosensor array. Selective multivalent interactions of the CPs with mammalian cell surfaces caused differential change in FRET signals, providing a fingerprint signature for each cell type. The resulting fluorescence signatures allowed the identification of 16 different cell types and discrimination between healthy, cancerous, and metastatic cells, with the same genetic background. While the CP-GFP sensor array completely differentiated between the cell types, only partial classification was achieved for the CPs alone, validating the effectiveness of the ratiometric sensor. The utility of the biosensor was further demonstrated in the detection of blinded unknown samples, where 121 of 128 samples were correctly identified. Notably, this selectivity-based sensor stratified diverse cell types in minutes, using only 2000 cells, without requiring specific biomarkers or cell labeling.

Non-invasive biomarkers in pancreatic cancer diagnosis: what we need versus what we have

Pancreatic cancer (PC) is probably the most lethal tumor being forecast as the second most fatal cancer by 2020 in developed countries. Only the earliest forms of the disease are a curable disease but it has to be diagnosed before symptoms starts. Detection at curable phase demands screening intervention for early detection and differential diagnosis. Unfortunately, no successful strategy or image technique has been concluded as effective approach and currently non-invasive biomarkers are the hope. Multiple translational research studies have explored minimally or non-invasive biomarkers in biofluids-blood, urine, stool, saliva or pancreatic juice, but diagnostic performance has not been validated yet. Nowadays no biomarker, alone or in combination, has been superior to carbohydrate antigen 19-9 (CA19-9) in sensitivity and specificity. Although the number of novel biomarkers for early diagnosis of PC has been increasing during the last couple of years, no molecular signature is ready to be implemented in clinical routine. Under the uncertain future, miRNAs profiling and methylation status seem to be the most promising biomarkers. However, good results in larger validations are urgently needed before application. Industry efforts through biotech and pharmaceutical companies are urgently required to demonstrate accuracy and validate promising results from basic and translational results.

MicroRNA-197 inhibits cell proliferation by targeting GAB2 in glioblastoma

Glioblastoma is the most common type of primary brain tumor in adults, and is usually fatal in a short duration. Acquiring a better understanding of the pathogenic mechanisms of glioblastoma is essential to the design of effective therapeutic strategies. Grb2-associated binding protein 2 (GAB2) is a member of the daughter of sevenless/Gab family of scaffolding adapters, and has been reported to be important in the development and progression of human cancer. Previously, it has been reported that GAB2 is expressed at high levels in glioma, and may serve as a useful prognostic marker for glioma and a novel therapeutic target for glioma invasion intervention. Elucidating why GAB2 is overexpressed in glioma, and investigating how to downregulate it will assist in further understanding the pathogenesis and progression of the disease, and to offer novel targets for therapy. The present study used in situ hybridization to detect microRNA (miR)‑197 expression levels and Targetscan to predict that the 3'-UTR of GAB2 was targeted by miR-197. Northern blotting and reverse transcription‑quantitative polymerase chain reaction were also conducted in the current study. miR-197 is downregulated in glioblastoma tissues, compared with adjacent normal tissues, however it involvement continues to be detected in the disease. The results of the present study demonstrated that miR‑197, as a tumor suppressor gene, inhibited proliferation by regulating GAB2 in glioblastoma cells. Furthermore, GAB2 was not only upregulated in glioma, but its expression levels were also associated with the grades of glioma severity. In addition, overexpression of GAB2 suppressed the expression of miR‑197 in glioblastoma cells. Therefore, restoration of miR‑197 and targeting GAB2 may be used, in conjunction with other therapies, to prevent the progression of glioblastoma.

Developments in miRNA gene signaling pathways in pancreatic cancer

Pancreatic cancer is a devastating malignancy that ranks as the fourth leading cause of cancer-related deaths worldwide. Dismal prognosis is mainly attributable to limited knowledge of the molecular pathogenesis of the disease. miRNAs have been found to be deregulated in pancreatic cancer, affecting several steps of initiation and aggressiveness of the disease by regulating important signaling pathways, such as the KRAS and Notch pathways. Moreover, the effect of miRNAs on regulating cell cycle events and expression of transcription factors has gained a lot of attention. Recent studies have highlighted the application of miRNAs as biomarkers and therapeutic tools. The current review focuses on latest advances with respect to the roles of miRNAs in pancreatic ductal adenocarcinoma associated signaling pathways and miRNA-based therapeutics.

Transcriptional Regulation of miR-31 by Oncogenic KRAS Mediates Metastatic Phenotypes by Repressing RASA1

Activating KRAS mutations are nearly ubiquitous in pancreatic cancer occurring in more than 95% of clinical cases. miRNAs are small noncoding RNAs that regulate gene expression by binding sequences within the 3'UTRs of target mRNAs. An integral role for miRNAs in cancer pathogenesis is well established; however, the role of miRNAs in KRAS-mediated tumorigenesis is poorly characterized. Here it is demonstrated that expression of miR-31 is coupled to the expression of oncogenic KRAS and activity of the MAPK pathway. miR-31 is highly expressed in patient-derived xenografts and a panel of pancreatic and colorectal cancer cells harboring activating KRAS mutations. The miR-31 host gene is a large noncoding RNA that correlates with miR-31 expression and enabled identification of the putative miR-31 promoter. Using luciferase reporters, a minimal RAS-responsive miR-31 promoter was found to drive robust luciferase activity dependent on expression of mutant KRAS and the transcription factor ELK1. Furthermore, ELK1 interacts directly with the endogenous miR-31 promoter in a MAPK-dependent manner. Expression of enforced miR-31 significantly enhanced invasion and migration of multiple pancreatic cancer cells resulting from the activation of RhoA through regulation of the miR-31 target gene RASA1. Importantly, acute knockdown of RASA1 phenocopied enforced miR-31 expression on the migratory behavior of pancreatic cancer cells through increased RhoA activation.

IMPLICATIONS

Oncogenic KRAS can activate Rho through the miR-31-mediated regulation of RASA1 indicating miR-31 acts as a KRAS effector to modulate invasion and migration in pancreatic cancer.

MicroRNA-133a inhibits the malignant behavior of glioma via downregulation of matrix metallopeptidase 9

MicroRNA (miR)-133a expression has been reported to be downregulated in numerous human malignancies. However, the expression levels and function of miR-133a have not yet been investigated in human glioma. In the present study, the expression of miR‑133a was analyzed by reverse transcription‑quantitative polymerase chain reaction. Following transfection of miR‑133a, cell proliferation, cell migration, cell invasion and luciferase assays, and western blot analysis were conducted in glioma cell lines. The present study demonstrated that miR‑133a was downregulated in human glioma tissues compared with in normal adjacent tissues. In addition, the results indicated that miR‑133a was likely to directly target matrix metallopeptidase 9 in glioma. These results suggest that miR-133a may be considered as a target for the treatment of human glioma.

Diagnostic and therapeutic biomarkers in pancreaticobiliary malignancy

Pancreatic ductal adenocarcinoma (PDAC) and cholangiocarcinoma (CCA) are two malignancies that carry significant morbidity and mortality. The poor prognoses of these cancers are strongly related to lack of effective screening modalities as well as few therapeutic options. In this review, we highlight novel biomarkers that have the potential to be used as diagnostic, prognostic and predictive markers. The focus of this review is biomarkers that can be evaluated on endoscopically-obtained biopsies or brush specimens in the pre-operative setting. We also provide an overview of novel serum based markers in the early diagnosis of both PDAC and CCA. In pancreatic cancer, the emphasis is placed on prognostic and theranostic markers, whereas in CCA the utility of molecular markers in diagnosis and prognosis are highlighted.

Lgr5 expression, cancer stem cells and pancreatic cancer: results from biological and computational analyses

AIMS

To determine the relationship between Lgr5 and other stemness markers and pathologic features in pancreatic ductal adenocarcinoma (PDAC) samples.

MATERIALS & METHODS

In 69 samples, Lgr5 was analyzed by qRT-PCR together with a panel of 29 genes. Bioinformatic analysis was carried out to identify a possible pathway regulating Lgr5 expression in PDAC.

RESULTS

Lgr5 expression was not associated with the expression of tested cancer stem cell markers. Moreover, it was not an independent predictor of survival neither at univariate analysis (p = 0.21) nor at multivariate analysis (p = 0.225).

CONCLUSION

Based on the lack of correlation between Lgr5 and tested cancer stem cell markers, Lgr5 does not seem to be a potential stemness marker or prognostic factor in PDAC.

Differential expression of miRNAs in pancreatobiliary type of periampullary adenocarcinoma and its associated stroma

Periampullary adenocarcinomas can be of two histological subtypes, intestinal or pancreatobiliary. The latter is more frequent and aggressive, and characterized by a prominent desmoplastic stroma, which is tightly related to the biology of the cancer, including its poor response to chemotherapy. Whereas miRNAs are known to regulate various cellular processes and interactions between cells, their exact role in periampullary carcinoma remains to be characterized, especially with respect to the prominent stromal component of pancreatobiliary type cancers. The present study aimed at elucidating this role by miRNA expression profiling of the carcinomatous and stromal component in twenty periampullary adenocarcinomas of pancreatobiliary type. miRNA expression profiles were compared between carcinoma cells, stromal cells and normal tissue samples. A total of 43 miRNAs were found to be differentially expressed between carcinoma and stroma of which 11 belong to three miRNA families (miR-17, miR-15 and miR-515). The levels of expression of miRNAs miR-17, miR-20a, miR-20b, miR-223, miR-10b, miR-2964a and miR-342 were observed to be higher and miR-519e to be lower in the stromal component compared to the carcinomatous and normal components. They follow a trend where expression in stroma is highest followed by carcinoma and then normal tissue. Pathway analysis revealed that pathways regulating tumor-stroma interactions such as ECM interaction remodeling, epithelial-mesenchymal transition, focal adhesion pathway, TGF-beta, MAPK signaling, axon guidance and endocytosis were differently regulated. The miRNA-mRNA mediated interactions between carcinoma and stromal cells add new knowledge regarding tumor-stroma interactions.

MicroRNA in pancreatic ductal adenocarcinoma and its precursor lesions

Pancreatic ductal adenocarcinoma (PDAC) is the 4^th deadliest cancer in the United States, due to its aggressive nature, late detection, and resistance to chemotherapy. The majority of PDAC develops from 3 precursor lesions, pancreatic intraepithelial lesions (PanIN), intraductual papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm. Early detection and surgical resection can increase PDAC 5-year survival rate from 6% for Stage IV to 50% for Stage I. To date, there are no reliable biomarkers that can detect PDAC. MicroRNAs (miRNA) are small noncoding RNAs (18-25 nucleotides) that regulate gene expression by affecting translation of messenger RNA (mRNA). A large body of evidence suggests that miRNAs are dysregulated in various types of cancers. MiRNA has been profiled as a potential biomarker in pancreatic tumor tissue, blood, cyst fluid, stool, and saliva. Four miRNA biomarkers (miR-21, miR-155, miR-196, and miR-210) have been consistently dysregulated in PDAC. MiR-21, miR-155, and miR-196 have also been dysregulated in IPMN and PanIN lesions suggesting their use as early biomarkers of this disease. In this review, we explore current knowledge of miRNA sampling, miRNA dysregulation in PDAC and its precursor lesions, and advances that have been made in using miRNA as a biomarker for PDAC and its precursor lesions.

miRNA-21 and miRNA-34a Are Potential Minimally Invasive Biomarkers for the Diagnosis of Pancreatic Ductal Adenocarcinoma

OBJECTIVES

Pancreatic ductal adenocarcinoma (PDAC) is one of the most deadly cancers, and its diagnosis often requires invasive procedures. Deregulated miRNA expression has been described in patients with PDAC. In this study, we analyzed the expression levels of 6 miRNAs (miR-21, -34a, -155, -196a, -200b, and -376a involved in PDAC tumorigenesis) in serum and salivary samples to assess their potential role as circulating diagnostics biomarkers.

METHODS

Serum and salivary samples were collected from patients with PDAC and healthy controls, and miRNA levels were quantified using qRT-PCR. Twenty-four patients with PDAC and 10 healthy controls were recruited.

RESULTS

A significant difference between PDAC and healthy groups was observed for the expression of miR-21 and miR-34a (P < 0.001 and P = 0.001) in serum samples. Both miRNAs accurately discriminated between the 2 groups, with an area under the curve for miR-21 and miR-34a of 0.889 (P = 0.001) and 0.865 (P = 0.002), respectively. In general, the expression of miRNAs between salivary samples did not differ.

CONCLUSIONS

Serum miR-21 and miR-34a are potentially useful diagnostic biomarkers of PDAC. In addition, our results suggest that these miRNAs are not differentially expressed in saliva, making them unsuitable for use as noninvasive biomarkers for diagnostic purposes.

A MicroRNA Panel in Pancreatic Cyst Fluid for the Risk Stratification of Pancreatic Cysts in a Prospective Cohort

A subset of pancreatic cystic neoplasms are regarded as precursor lesions of pancreatic cancer, but only a minority of all pancreatic cystic neoplasms will undergo malignant transformation. MicroRNAs are increasingly recognized as molecular targets in carcinogenesis. Previously, a 9-microRNA (miR) signature was suggested to discriminate between high risk and low risk pancreatic cystic neoplasm. In this study, we aimed to validate this 9-miR panel in a prospective cohort. Total miR was isolated from pancreatic cyst fluid and expression of miR18a, miR24, miR30a-3p, miR92a, miR99b, miR106b, miR142-3p, miR342-3p, and miR532-3p was analyzed by singleplex Taqman MicroRNA Assay. A total of 62 patient samples were analyzed. During follow-up, 24 (38.7%) patients underwent resection, of which 6 (9.7%) patients showed at least high grade dysplasia. A logistic regression model presented a “predicted risk” score which significantly differed between low and high risk cysts, either including all patients or only those with histological confirmation of diagnosis. Using a set cut-off of 50%, the sensitivity of the model for the total cohort was 10.0%, specificity 100.0%, positive predicted value 100.0%, negative predicted value 85.2%, and diagnostic accuracy of 85.5%. Thus, while observing a significant difference between low and high risk cysts, clinical implementation of this biomarker panel is as yet unlikely to be beneficial in the management of pancreatic cysts.

miRNAs As Diagnostic and Prognostic Biomarkers in Pancreatic Ductal Adenocarcinoma and Its Precursor Lesions: A Review

Pancreatic ductal adenocarcinoma (PDAC), a rare but lethal tumor, is difficult to diagnose without performing an invasive procedure. miRNAs are known to be deregulated in PDAC patients, and recent studies have shown that they can be used as diagnostic and prognostic of the disease. The detection of miRNAs in samples acquired through minimally or noninvasive procedures, such as serum, plasma, and saliva, can have a positive impact on the clinical management of these patients. This article is a comprehensive review of the major studies that have evaluated the expression of miRNAs as biomarkers in pancreatic cancer and its premalignant lesions.