Development of a miRNA-based diagnostic assay for pancreatic ductal adenocarcinoma

Senescence-Associated miRNAs and Their Role in Pancreatic Cancer

Replicative senescence is irreversible cell proliferation arrest for somatic cells which can be circumvented in cancers. Cellular senescence is a process, which may play two opposite roles. On the one hand, this is a natural protection of somatic cells against unlimited proliferation and malignant transformation. On the other hand, cellular secretion caused by senescence can stimulate inflammation and proliferation of adjacent cells that may promote malignancy. The main genes controlling the senescence pathways are also well known as tumor suppressors. Almost 140 genes regulate both cellular senescence and cancer pathways. About two thirds of these genes (64%) are regulated by microRNAs. Senescence-associated miRNAs can stimulate cancer progression or act as tumor suppressors. Here we review the role playing by senescence-associated miRNAs in development, diagnostics and treatment of pancreatic cancer.

microRNA-based diagnostic and therapeutic applications in cancer medicine

It has been almost two decades since the first link between microRNAs and cancer was established. In the ensuing years, this abundant class of short noncoding regulatory RNAs has been studied in virtually all cancer types. This tremendously large body of research has generated innovative technological advances for detection of microRNAs in tissue and bodily fluids, identified the diagnostic, prognostic, and/or predictive value of individual microRNAs or microRNA signatures as potential biomarkers for patient management, shed light on regulatory mechanisms of RNA-RNA interactions that modulate gene expression, uncovered cell-autonomous and cell-to-cell communication roles of specific microRNAs, and developed a battery of viral and nonviral delivery approaches for therapeutic intervention. Despite these intense and prolific research efforts in preclinical and clinical settings, there are a limited number of microRNA-based applications that have been incorporated into clinical practice. We review recent literature and ongoing clinical trials that highlight most promising approaches and standing challenges to translate these findings into viable microRNA-based clinical tools for cancer medicine. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Can microRNA become next-generation tools in molecular diagnostics and therapeutics? A systematic review

Background

MicroRNAs (miRNAs) represent a novel class of single-stranded RNA molecules of 18–22 nucleotides that serve as powerful tools in the regulation of gene expression. They are important regulatory molecules in several biological processes.

Main body

Alteration in the expression profiles of miRNAs have been found in several diseases. It is anticipated that miRNA expression profiling can become a novel diagnostic tool in the future.

Hence, this review evaluates the implications of miRNAs in various diseases and the recent advances in miRNA expression level detection and their target identification. A systematic approach to review existing literature available on databases such as Medline, PubMed, and EMBASE was conducted to have a better understanding of mechanisms mediating miRNA-dependent gene regulation and their role as diagnostic markers and therapeutic agents.

Conclusion

A clear understanding of the complex multilevel regulation of miRNA expression is a prerequisite to explicate the origin of a wide variety of diseases. It is understandable that miRNAs offer potential targets both in diagnostics and therapeutics of a multitude of diseases. The inclusion of specific miRNA expression profiles as biomarkers may lead to crucial advancements in facilitating disease diagnosis and classification, monitoring its prognosis, and treatment. However, standardization of methods has a pivotal role in the success of extensive use of miRNA expression profiling in routine clinical settings.

LINC01133: an emerging tumor-associated long non-coding RNA in tumor and osteosarcoma

Emerging evidence suggested that long non-coding RNAs (lncRNAs) play pivotal roles in tumorigenesis. LINC01133 is a newly identified lncRNA first discovered as an oncogene in lung squamous cell carcinoma. Subsequent studies further demonstrated this lncRNA was deregulated in a wide spectrum of tumors, including colorectal, gastric, lung, and pancreatic ductal adenocarcinoma as well as osteosarcoma and hepatocellular carcinoma. Intriguingly, this lncRNA exerted oncogenic or tumor-suppressive action in a tissue-dependent manner. This review sought to summarize our current understanding concerning the deregulation of LINC01133 in human tumors in relation to its molecular mechanisms and cellular functions. The clinical utilization of LINC01133 as a potential prognostic biomarker and a treatment target is also discussed.

Key Regulatory miRNAs and their Interplay with Mechanosensing and Mechanotransduction Signaling Pathways in Breast Cancer Progression

According to the WHO, breast cancer is the most common cancer in women worldwide. Identification of underlying mechanisms in breast cancer progression is the main concerns of researches. The mechanical forces within the tumor microenvironment, in addition to biochemical stimuli such as different growth factors and cytokines, activate signaling cascades, resulting in various changes in cancer cell physiology. Cancer cell proliferation, invasiveness, migration, and, even, resistance to cancer therapeutic agents are changed due to activation of mechanotransduction signaling. The mechanotransduction signaling is frequently dysregulated in breast cancer, indicating its important role in cancer cell features. So far, a variety of experimental investigations have been conducted to determine the main regulators of the mechanotransduction signaling. Currently, the role of miRNAs has been well-defined in the cancer process through advances in molecular-based approaches. miRNAs are small groups of RNAs (∼22 nucleotides) that contribute to various biological events in cells. The central role of miRNAs in the regulation of various mediators involved in the mechanotransduction signaling has been well clarified over the last decade. Unbalanced expression of miRNAs is associated with different pathologic conditions. Overexpression and downregulation of certain miRNAs were found to be along with dysregulation of mechanotransduction signaling effectors. This study aimed to critically review the role of miRNAs in the regulation of mediators involved in the mechanosensing pathways and clarify how the cross-talk between miRNAs and their targets affect the cell behavior and physiology of breast cancer cells.

Psoralen Suppresses Cisplatin-Mediated Resistance and Induces Apoptosis of Gastric Adenocarcinoma by Disruption of the miR196a-HOXB7-HER2 Axis

Purpose

The present study aimed to investigate the impact of psoralen on miR-196a-5p expression and function, and to reveal the mechanism underlying miR-196a-5p-mediated inhibition and the reversal of cisplatin (DDP) resistance.

Methods

Serum samples were collected from 50 patients with gastric cancer (GC), and the association between miR-196a-5p expression and the response to chemotherapy was assessed. A DDP-resistant GC cell line was also established to determine the effects of miR-196a-5p and psoralen on DDP resistance. MGC803 cells were transfected with miR-196a-5p mimic and inhibitor vectors for the overexpression and downregulation of miR-196a-5p, respectively.

Results

Clinical data analysis showed that the lower expression levels of miR-196a-5p were significantly associated with chemoresistance in patients with GC. Upregulation of miR-196a-5p significantly enhanced the anti-proliferative effect, apoptosis and sensitivity to DDP by regulating the protein expression levels of HOXB7, HER2, Bcl-2 and G₁/S-specific cyclin-D1 (CCND1). Furthermore, psoralen reversed miR-196a-5p-induced DDP resistance and reduced the expression levels of HOXB7, HER2, Bcl-2 and CCND1.

Conclusion

miR-196a-5p may be a novel biomarker of chemotherapeutic success in patients with GC and may also influence the sensitivity of GC cells to DDP. Moreover, psoralen can increase chemotherapeutic sensitivity by upregulating miR-196a-5p and then downregulating HOXB7-HER2 signaling axis.

miRNA and Gene Expression in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a challenging disease that is mostly diagnosed late in the course of the illness. Unlike other cancers in which measurable successes have been achieved with traditional chemotherapy, targeted therapy, and, recently, immunotherapy, PDAC has proved to be poorly responsive to these treatments, with only marginal to modest incremental benefits using conventional cytotoxic therapy. There is, therefore, a great unmet need to develop better therapies based on improved understanding of biology and identification of predictive and prognostic biomarkers that would guide therapy. miRNAs are small noncoding RNAs that regulate the expression of some key genes by targeting their 3'-untranslated mRNA region. Aberrant expression of miRNAs has been linked to the development of various malignancies, including PDAC. A series of miRNAs have been identified as potential tools for early diagnosis, prediction of treatment response, and prognosis of patients with PDAC. In this review, we present a summary of the miRNAs that have been studied in PDAC in the context of disease biology.

Developing new TB biomarkers, are miRNA the answer?

Efforts to reduce the global TB burden are hindered by the lack of simple, reliable non-sputum based diagnostics. To date studies investigating the biomarker potential of circulating host proteins and mRNA have not shown sufficient diagnostic utility. Recently, there has been increasing interest in circulating miRNA as a biomarker of TB disease. This review examined all published miRNA-TB biomarker studies to determine if a reproducible miRNA signature of TB disease could be elucidated. From 15 miRNA profiling studies, 894 miRNA differentially expressed between TB patients and healthy controls were identified in at least one study. Of these, 143 miRNA were validated by qPCR with 53 differentially expressed between TB patients and controls. Interestingly, only 8 of these miRNA were identified in 2 or more studies, and no consensus on a reproducible miRNA signature for identification of TB disease could be identified. TB disease is clearly associated with a wide breadth of differentially expressed miRNA. This review highlights our recent progress and the multiple factors, including environment, source of tissue, ethnicity and extent of TB disease that may influence miRNA expression. Coordinated efforts are required to validate identified targets in multiple populations to progress miRNA biomarker development.

Statistical Methods for Identifying Biomarkers from miRNA Profiles of Cancers

Biomarkers play important roles in early diagnosis and treatment plan for cancer patients and the importance is growing. With advances in high-throughput molecular profiling technology for various types of molecules such as DNA, RNA, proteins, or metabolites, it is now possible to perform massive profiling analysis that allows accelerating discovery of novel biomolecules. Because no single marker is sufficiently accurate for clinical use, the cancer biomarker is developed in the form of multiple biomarker panels. No single marker is sufficiently accurate for clinical use, and thus cancer biomarkers are developed in the form of multiple biomarker panels. Of various types of molecular biomarkers, microRNA (miRNA) has emerged as a class of promising cancer biomarker recently. MiRNAs are small noncoding RNAs that regulate gene expression. The chapter overviews the process of identification of biomarker panels from miRNA profiles focusing on statistical methods. Introduction to molecular cancer biomarkers is touched first. From sample design to miRNA profiling process is reviewed in the method section.Statistical methods for biomarker development are introduced according to three typical purposes of molecular biomarkers: tumor subtype classification, early detection, and prediction of treatment response or prognosis of patients. Example codes for R program are provided as well for selected methods.

The emerging role of liquid biopsy in diagnosis, prognosis and treatment monitoring of pancreatic cancer

Circulating tumor DNA, circulating tumor cells and tumor-related exosomes may offer new opportunities to provide insights into the biological and clinical characteristics of a neoplastic disease. They represent alternative routes for diagnostic and prognostic purposes, and for predicting and longitudinally monitoring response to treatment and disease progression. Hence, circulating biomarkers represent promising noninvasive tools in the scenario of pancreatic cancer, where neither molecular nor clinical predictors of treatment benefit have been identified yet. This review aims to provide an overview of the current status of circulating biomarker research in pancreatic cancer, and discusses their potential clinical utility to facilitate clinical decision-making.

Immunotherapy and Prevention of Pancreatic Cancer

Pancreatic cancer is the third-leading cause of cancer mortality in the USA, recently surpassing breast cancer. A key component of pancreatic cancer's lethality is its acquired immune privilege, which is driven by an immunosuppressive microenvironment, poor T cell infiltration, and a low mutational burden. Although immunotherapies such as checkpoint blockade or engineered T cells have yet to demonstrate efficacy, a growing body of evidence suggests that orthogonal combinations of these and other strategies could unlock immunotherapy in pancreatic cancer. In this Review article, we discuss promising immunotherapies currently under investigation in pancreatic cancer and provide a roadmap for the development of prevention vaccines for this and other cancers.

Epigenetic alterations as biomarkers in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) prognosis remains very poor and has only marginally improved during the last decades. Epigenetic alterations have been the focus of many recent studies and offer valuable options for PDAC detection, prognosis and treatment. DNA methylation, histone modifications and microRNA (miR) level changes can be used as biomarkers. These alterations occur early in carcinogenesis and may be specific for PDAC. Additionally, epigenetic alterations can be analyzed from cell-free DNA, free-circulating nucleosomes or shed tumor cells in blood. High-throughput methods are available for miR and DNA methylation level detection. In particular, multiple promising miR level changes have been discovered. No single epigenetic biomarker that offers a sufficient specificity has been discovered yet, but patterns containing multiple independent biomarkers exist.

Achieving resistance specificity in prostate cancer

Prostate (CaP) cancer is the second-leading cause of cancer-related mortality in men in Western societies. Androgen receptor (AR) signaling is a critical survival pathway for prostate cancer cells, and androgen-deprivation therapy (ADT) remains the principal treatment for patients with locally advanced and metastatic disease. Although a majority of patients initially respond to ADT, most will eventually develop castrate resistance. The recent discovery that AR signaling persists during systemic castration via intratumoral production of androgens led to the development of novel anti-androgen therapies. Although these therapies effectively palliate symptoms and prolong life, metastatic castration-resistant prostate cancer remains incurable. Recent studies suggest that epithelial plasticity, which covers a range of changes in differentiation and cell behavior, with full epithelial integrity at one end and epithelial-mesenchymal Transition (EMT) as the full realization of a plasticity is regulated by microRNAs (miRNAs). MicroRNAs are involved in human tumourigenesis and are aberrantly expressed in CaP cell lines, xenografts and clinical tissues and is associated with enhanced survival signaling, proliferation, migration, invasion, integrin-mediated adhesion, EMT, and drug resistance. Due to the oncogenic or tumor suppressive properties of CaP-related miRNAs, they are likely to be of clinical use as therapeutic targets for prostate cancer treatment in the near future. This review summarizes our current understanding of CaP and castration-recurrent CaP (CR-CaP) to earlier studies that characterized ADT and the molecular mechanisms that facilitate the transition from androgen-stimulated CaP to CR-CaP.

The role of microRNA-196a in tumorigenesis, tumor progression, and prognosis

MicroRNAs are a large group of non-coding RNAs that have emerged as regulators of various biological processes, especially carcinogenesis and cancer progression. Recent evidence has shown that microRNA-196a (miR-196a) is upregulated in most types of tumors and involved in multiple biological processes via translational inhibition and mRNA cleavage, such as cell proliferation, migration, and invasion, mostly functioning as an oncogene. Dysregulation of miR-196a promotes oncogenesis and tumor progression. In this review, we summarize the upstream regulators, target genes, signaling pathways, and single nucleotide polymorphisms of miR-196a, which collectively affect cell proliferation, migration, and invasion. In addition, we review the clinical outcomes and significance of miR-196a. miR-196a may serve as a novel biomarker or target for diagnosis, prognosis, and therapy in several human cancers.

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.

The management of thyroid nodules and cancer in the molecular era

The incidence of thyroid cancer is increasing worldwide. Current standards in the diagnosis and management of thyroid cancer are limited by the uncertainty of fine-needle aspiration samples that are indeterminate in nature. Molecular markers have the potential to improve the accuracy of thyroid fine-needle aspiration and to aid the physician in giving a more accurate diagnosis and prognosis. This paper summarizes the various molecular markers currently available.

miRNA - Therapeutic tool in breast cancer? Where are we now?

OBJECTIVE

The aim of this study was to review the current knowledge about involvement of microRNAs in breast cancer, and their potential in the clinic, published in scientific journals searched in Pubmed/Medline database until March 2014.

RESULTS

MicroRNAs (miRNAs) are a family of 21-25 nucleotide small RNAs molecules. Currently, it is well known that miRNA plays a key role in all cellular processes of the organism including tumour initiation and progression. Many studies have shown that circulating miRNAs are attractive, easily detectable tumour biomarkers. Breast cancer is one of the most common cancers in the world. It is clinically established that different subtypes may respond differently to therapies, give metastases and present drug resistance. MicroRNAs have a potential as diagnostic, prognostic and therapeutic tools in breast cancer.

CONCLUSION

Molecular knowledge is crucial for choosing the most effective therapy for individual patients. MicroRNAs holds a great potential in anticancer therapy.

Evaluation of a novel functional single-nucleotide polymorphism (rs35010275 G>C) in MIR196A2 promoter region as a risk factor of gastric cancer in a Chinese population

Single-nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) have been suggested to influence the occurrence and progression of cancer through altering the expression and biological function of miRNAs. The aim of this study was to investigate whether the potential functional SNPs in MIR196A2 promoter had effect on the susceptibility to gastric cancer (GC) in a Chinese population.We conducted a 2-stage case-control study (753 cases and 854 controls in testing set; 940 cases and 1061 controls in validation set) to evaluate the association between 2 potential functional SNPs in MIR196A2 promoter (rs12304647 A>C and rs35010275 G>C) and GC risk. The luciferase reporter assay and electrophoretic mobility shift assay were used to examine the functionality of the important polymorphism.We found that the rs35010275 C allele was significantly associated with the decreased risk of GC (adjusted odds ratio = 0.85, 95% confidence interval = 0.77-0.94) in the combined case-control studies. The miR-196a expression levels in GC tissues were significantly higher than that in corresponding adjacent normal tissues (P < 0.001). Besides, each allele of rs35010275 displayed completely opposite effects to influence the transcription activity of MIR196A2 promoter via recruiting different transcription factors or complexes.The functional rs35010275 G>C polymorphism in MIR196A2 promoter was significantly associated with miR-196a expression and influenced the genetic susceptibility to GC.

A microRNA-based test improves endoscopic ultrasound-guided cytologic diagnosis of pancreatic cancer

BACKGROUND & AIMS

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in combination with cytopathology is the optimal method for diagnosis and staging of pancreatic ductal adenocarcinoma (PDAC) and other pancreatic lesions. Its clinical utility, however, can be limited by high rates of indeterminate or false-negative results. We aimed to develop and validate a microRNA (miRNA)-based test to improve preoperative detection of PDAC.

METHODS

Levels of miRNAs were analyzed in a centralized clinical laboratory by relative quantitative polymerase chain reaction in 95 formalin-fixed paraffin-embedded specimens and 228 samples collected by EUS-FNA during routine evaluations of patients with solid pancreatic masses at 4 institutions in the United States, 1 in Canada, and 1 in Poland.

RESULTS

We developed a 5-miRNA expression classifier, consisting of MIR24, MIR130B, MIR135B, MIR148A, and MIR196, that could identify PDAC in well-characterized, formalin-fixed, paraffin-embedded specimens. Detection of PDAC in EUS-FNA samples increased from 78.8% by cytology analysis alone (95% confidence interval, 72.2%-84.5%) to 90.8% when combined with miRNA analysis (95% confidence interval, 85.6%-94.5%). The miRNA classifier correctly identified 22 additional true PDAC cases among 39 samples initially classified as benign, indeterminate, or nondiagnostic by cytology. Cytology and miRNA test results each were associated significantly with PDAC (P < .001), with positive predictive values greater than 99% (95% confidence interval, 96%-100%).

CONCLUSIONS

We developed and validated a 5-miRNA classifier that can accurately predict which preoperative pancreatic EUS-FNA specimens contain PDAC. This test might aid in the diagnosis of pancreatic cancer by reducing the number of FNAs without a definitive adenocarcinoma diagnosis, thereby reducing the number of repeat EUS-FNA procedures.

miRNAs in human papilloma virus associated oral and oropharyngeal squamous cell carcinomas

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer in the world with 600,000 new cases diagnosed annually. Tobacco and alcohol use have been associated as the principal etiological factors of this pathogenesis. The incidence of smoking-associated HNSCC has declined, while human papilloma virus (HPV)-associated HNSCC is on the rise. There are currently no clinically validated biomarkers to detect this cancer at an early stage (cancers independent of HPV status). It is well-established that the aberrant expression of miRNAs can lead to tumorigenesis. miRNA expression differences have also been demonstrated in HPV-positive and HPV-negative HNSCC tumor tissues as well as in body fluids. Therefore, miRNAs have the potential to provide an unprecedented insight into the pathogenesis of HNSCC and serve as potential biomarkers. This review addresses HNSCC disease burden and the regulation of miRNA by HPV viral oncoproteins, potential miRNA biomarkers and future perspectives. miRNA provides an unique opportunity to fulfill the current clinical challenge in HNSCC patient management by enabling early detection followed by targeted interventions, leading to a significant reduction in mortality and morbidity.

Tissue slide-based microRNA characterization of tumors: how detailed could diagnosis become for cancer medicine?

miRNAs are short, non-coding, regulatory RNAs that exert cell type-dependent, context-dependent, transcriptome-wide gene expression control under physiological and pathological conditions. Tissue slide-based assays provide qualitative (tumor compartment) and semi-quantitative (expression levels) information about altered miRNA expression at single-cell resolution in clinical tumor specimens. Reviewed here are key technological advances in the last 5 years that have led to implementation of fully automated, robust and reproducible tissue slide-based assays for in situ miRNA detection on US FDA-approved instruments; recent tissue slide-based discovery studies that suggest potential clinical applications of specific miRNAs in cancer medicine are highlighted; and the challenges in bringing tissue slide-based miRNA assays into the clinic are discussed, including clinical validation, biomarker performance, biomarker space and integration with other biomarkers.

MicroRNAs as emerging biomarkers and therapeutic targets for pancreatic cancer

Despite tremendous efforts from scientists and clinicians worldwide, pancreatic adenocarcinoma (PDAC) remains a deadly disease due to the lack of early diagnostic tools and reliable therapeutic approaches. Consequently, a majority of patients (80%) display an advanced disease that results in a low resection rate leading to an overall median survival of less than 6 months. Accordingly, robust markers for the early diagnosis and prognosis of pancreatic cancer, or markers indicative of survival and/or metastatic disease are desperately needed to help alleviate the dismal prognosis of this cancer. In addition, the discovery of new therapeutic targets is mandatory to design effective treatments. In this review, we will highlight the translational studies demonstrating that microRNAs may soon translate into clinical applications as long-awaited screening tools and therapeutic targets for PDAC.

Role of endoscopic ultrasound in the molecular diagnosis of pancreatic cancer

Pancreatic ductal adenocarcinoma remains one of the most deadly types of tumor. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a safe, cost-effective, and accurate technique for evaluating and staging pancreatic tumors. However, EUS-FNA may be inconclusive or doubtful in up to 20% of cases. This review underlines the clinical interest of the molecular analysis of samples obtained by EUS-FNA in assessing diagnosis or prognosis of pancreatic cancer, especially in locally advanced tumors. On EUS-FNA materials DNA, mRNA and miRNA can be extracted, amplified, quantified and subjected to methylation assay. Kras mutation assay, improves diagnosis of pancreatic cancer. When facing to clinical and radiological presentations of pseudo-tumorous chronic pancreatitis, wild-type Kras is evocative of benignity. Conversely, in front of a pancreatic mass suspected of malignancy, a mutated Kras is highly evocative of pancreatic adenocarcinoma. This strategy can reduce false-negative diagnoses, avoids the delay of making decisions and reduces loss of surgical resectability. Similar approaches are conducted using analysis of miRNA expression as well as Mucin or markers of invasion (S100P, S100A6, PLAT or PLAU). Beyond the diagnosis approach, the prediction of response to treatment can be also investigated form biomarkers expression within EUS-FNA materials.

Investigating MicroRNA Expression Profiles in Pancreatic Cystic Neoplasms

OBJECTIVES:

Current diagnostic tools for pancreatic cysts fail to reliably differentiate mucinous from nonmucinous cysts. Reliable biomarkers are needed. MicroRNAs (miRNA) may offer insights into pancreatic cysts. Our aims were to (1) identify miRNAs that distinguish benign from both premalignant cysts and malignant pancreatic lesions using formalin-fixed, paraffin-embedded (FFPE) pathology specimens; (2) identify miRNAs that distinguish mucinous cystic neoplasm (MCN) from branch duct-intraductal papillary mucinous neoplasm (BD-IPMN).

METHODS:

A total of 69 FFPE pancreatic specimens were identified: (1) benign (20 serous cystadenoma (SCA)), (2) premalignant (10 MCN, 10 BD-IPMN, 10 main duct IPMN (MD-IPMN)), and (3) malignant (19 pancreatic ductal adenocarcinoma (PDAC)). Total nucleic acid extraction was performed followed by miRNA expression profiling of 378 miRNAs interrogated using TaqMan MicroRNA Arrays Pool A and verification of candidate miRNAs. Bioinformatics was used to generate classifiers.

RESULTS:

MiRNA profiling of 69 FFPE specimens yielded 35 differentially expressed miRNA candidates. Four different 4-miRNA panels differentiated among the lesions: one panel separated SCA from MCN, BD-IPMN, MD-IPMN, and PDAC with sensitivity 85% (62, 97), specificity 100% (93, 100), a second panel distinguished MCN from SCA, BD-IPMN, MD-IPMN, and PDAC with sensitivity and specificity 100% (100, 100), a third panel differentiated PDAC from IPMN with sensitivity 95% (76, 100) and specificity 85% (72, 96), and the final panel diagnosed MCN from BD-IPMN with sensitivity and specificity approaching 100%.

CONCLUSIONS:

MiRNA profiling of surgical pathology specimens differentiates serous cystadenoma from both premalignant pancreatic cystic neoplasms and PDAC and MCN from BD-IPMN.

DNA methyltransferases and pancreatic cancer

Abnormal methylation of the promoter of suppressor genes plays an important role in the occurrence and development of pancreatic cancer. The degree of methylation is closely related to the activity of DNA methyltransferases. MicroRNAs (miRNAs) are a group of endogenous, small non-coding RNA that can regulate DNA methylation (DNA methylation can also regulate miRNAs) and affect the occurrence of pancreatic cancer. In recent years, demethylation drugs or RNA interference have been widely used to study the pathogenesis and targeted therapy of pancreatic cancer, and are expected to become effective means of treatment for pancreatic cancer. This article will give a review of the functions of DNA methyltransferases and the relationship between DNA methyltransferases and pancreatic cancer.

Therapeutic evaluation of microRNAs by molecular imaging

MicroRNAs (miRNAs) function as regulatory molecules of gene expression with multifaceted activities that exhibit direct or indirect oncogenic properties, which promote cell proliferation, differentiation, and the development of different types of cancers. Because of their extensive functional involvement in many cellular processes, under both normal and pathological conditions such as various cancers, this class of molecules holds particular interest for cancer research. MiRNAs possess the ability to act as tumor suppressors or oncogenes by regulating the expression of different apoptotic proteins, kinases, oncogenes, and other molecular mechanisms that can cause the onset of tumor development. In contrast to current cancer medicines, miRNA-based therapies function by subtle repression of gene expression on a large number of oncogenic factors, and therefore are anticipated to be highly efficacious. Given their unique mechanism of action, miRNAs are likely to yield a new class of targeted therapeutics for a variety of cancers. More than thousand miRNAs have been identified to date, and their molecular mechanisms and functions are well studied. Furthermore, they are established as compelling therapeutic targets in a variety of cellular complications. However, the notion of using them as therapeutic tool was proposed only recently, given that modern imaging methods are just beginning to be deployed for miRNA research. In this review, we present a summary of various molecular imaging methods, which are instrumental in revealing the therapeutic potential of miRNAs, especially in various cancers. Imaging methods have recently been developed for monitoring the expression levels of miRNAs and their target genes by fluorescence-, bioluminescence- and chemiluminescence-based imaging techniques. Mature miRNAs bind to the untranslated regions (UTRs) of the target mRNAs and regulate target genes expressions. This concept has been used for the development of fluorescent reporter-based imaging strategies to monitor the functional status of endogenous miRNAs, or the respective miRNAs transiently co-expressed in cells. Bioluminescence-based imaging strategies have been used to investigate various stages of miRNA processing and its involvement in different cellular processes. Similarly, chemiluminsecence methods were developed for in vitro miRNA imaging such as monitoring their therapeutic roles in various cancer cell lines.

Smoking and microRNA dysregulation: a cancerous combination

MicroRNAs (miRNAs) are post-transcriptional gene regulators that are differentially expressed in several pathophysiological conditions including cancer. They impact the disease course by modulating an array of putative target gene(s). Interestingly, there is a strong correlation between the various miRNAs target(s) and the smoking-regulated genes in cancer. This review article provides an insight into the current status of smoking-induced miRNAs and their genetic/epigenetic regulation in smoking-associated cancers, with a major focus on lung cancer (LC). Furthermore, it discusses the role of miRNAs in smoking-mediated oncogenic events in cancer and explores the diagnostic/prognostic potential of miRNA-based biomarkers and their efficacy as therapeutic targets.

Exosomes in prostate cancer: putting together the pieces of a puzzle

Exosomes have been shown to act as mediators for cell to cell communication and as a potential source of biomarkers for many diseases, including prostate cancer. Exosomes are nanosized vesicles secreted by cells and consist of proteins normally found in multivesicular bodies, RNA, DNA and lipids. As a potential source of biomarkers, exosomes have attracted considerable attention, as their protein content resembles that of their cells of origin, even though it is noted that the proteins, miRNAs and lipids found in the exosomes are not a reflective stoichiometric sampling of the contents from the parent cells. While the biogenesis of exosomes in dendritic cells and platelets has been extensively characterized, much less is known about the biogenesis of exosomes in cancer cells. An understanding of the processes involved in prostate cancer will help to further elucidate the role of exosomes and other extracellular vesicles in prostate cancer progression and metastasis. There are few methodologies available for general isolation of exosomes, however validation of those methodologies is necessary to study the role of exosomal-derived biomarkers in various diseases. In this review, we discuss “exosomes” as a member of the family of extracellular vesicles and their potential to provide candidate biomarkers for prostate cancer.

Circulating microRNAs as potential new biomarkers for prostate cancer

Since they were first described in the 1990s, circulating microRNAs (miRNAs) have provided an active and rapidly evolving area of current research that has the potential to transform cancer diagnostics and therapeutics. In particular, miRNAs could provide potential new biomarkers for prostate cancer, the most common cause of cancer in UK men. Current diagnostic tests for prostate cancer have low specificity and poor sensitivity. Further, although many prostate cancers are so slow growing as not to pose a major risk to health, there is currently no test to distinguish between these and cancers that will become aggressive and life threatening. Circulating miRNAs are highly stable and are both detectable and quantifiable in a range of accessible bio fluids, thus have the potential to be useful diagnostic, prognostic and predictive biomarkers. This review aims to summarise the current understanding of circulating miRNAs in prostate cancer patients and their potential role as biomarkers.

Circulating miRNAs: reflecting or affecting cardiovascular disease?

MicroRNAs are a class of small, noncoding RNAs encoded by the metazoan genome that regulate protein expression. A collection of studies point to vital roles for microRNAs in the onset and development of cardiovascular diseases. So far, microRNAs have been considered as important intracellular mediators in maintaining proper cardiac function and hemostasis, and have been proposed as potential therapeutic targets in cardiovascular disease. The recent discovery that microRNAs circulate in a stable form in many body fluids, including blood, suggests that circulating microRNAs can serve as a new generation of biomarkers for cardiovascular diseases. In this review, we summarize the findings of studies focusing on circulating microRNAs present in human blood cells or plasma/serum, where they potentially could serve as diagnostic or prognostic markers for a variety of cardiovascular pathologies, including acute myocardial infarction, heart failure, coronary artery disease, stroke, diabetes and hypertension. The significance and limitations of microRNAs as the new biomarker generation for cardiovascular disease are also discussed.

Detection methods for microRNAs in clinic practice

MicroRNAs (miRNA) are short non-coding RNA molecules that regulate gene expression. miRNAs profiles are specific for cell lineages and tissues, and their changes reflect pathological processes. This fact introduces the possibility of their use in diagnostics. The application of miRNAs in diagnostics is critically dependent on the establishment of miRNA profiles that can discriminate patients from normal healthy individuals with good sensitivity and specificity and on the development of methods for their accurate and high-throughput quantification. In this review, we present an overview of some of the different techniques and methods currently used to detect miRNAs. We focus on methods that can be employed in routine clinic diagnostics indicating their advantages as well as their shortcomings, with special attention being paid to the most innovative ones. Since disease-specific miRNAs can be found in blood serum, we also present emerging methods for the detection of circulating miRNAs as a way of fast, reliable and non-invasive diagnostic.

Defining a prognostic molecular profile for ductal adenocarcinoma of the pancreas highlights known key signaling pathways

There has been very little progress in improving outcomes for patients with pancreatic ductal adenocarcinoma (PDAC) over the past few decades. High-throughput array profiling has made it possible to discover new assays to diagnose or prognose PDAC more accurately based on the genetic profile of an individual tumor. To improve patient survival, there is a need to extract the most practical data to define tumor subgroups and personalize anticancer therapy. In the evaluated study, a multiplatform, survival-based analysis of molecular changes was performed for PDAC to discover clinically useful biomarkers. A composite score predictive for survival was calculated for individual genes, taking into account the DNA copy-number and any regulation by miRNAs. Several genes involved in the PI3K/AKT and SRC signaling pathways were identified and further investigated.

Circulating microRNAs: macro-utility as markers of prostate cancer?

The realization that microRNAs (miRNAs) are frequently deregulated in malignancy has had a major impact on cancer research. In particular, the recent finding that highly stable forms of miRNAs can be accurately measured in body fluids, including blood, has generated considerable excitement. Here, we discuss the potential of blood-based circulating miRNAs as diagnostic, prognostic, and predictive biomarkers of prostate cancer. We also describe practical considerations that may influence identification and/or measurement of miRNA biomarkers in the circulation. Finally, evidence is prevented for the emerging concept that circulating miRNAs are actively released by their cells of origin and can modulate gene expression at distal sites. These mobile miRNAs, which we term 'hormomirs' because of their hormone-like characteristics, could act as local or long-range signals to maintain normal homeostasis or influence the development and progression of diseases such as cancer.

Aberrant expression of miR-196a in gastric cancers and correlation with recurrence

MicroRNAs (miRNAs) are short noncoding RNAs (~22 nt) that play important roles in the pathogenesis of human diseases by negatively regulating gene expression. Here, we examined the relationship between miR-196a and gastric cancer.By the analysis of 72 gastric cancer samples, we found that the expression level of miR-196a microRNA significantly increased in primary gastric cancer tissues versus adjacent normal tissues. In addition, extracellular miR-196a detected in conditioned medium was strongly correlated with its cellular expression status and increased circulating miR-196a in patient serum was associated with gastric cancer disease status and relapse. Furthermore, ectopic expression of miR-196a microRNA promoted the epithelial-mesenchymal transition and migration/invasion capabilities of transfected cells, suggesting its oncogenic potential in gastric cancer progression. Altogether, our data demonstrate that miR-196a exerts an oncogenic role in gastric cancer and miR-196a may be a novel biomarker for detecting gastric cancer and for monitoring disease recurrence.

Integrating contextual miRNA and protein signatures for diagnostic and treatment decisions in cancer

The promise of personalized medicine is highly dependent on the identification of biomarkers that inform diagnostic decisions and treatment options, as well as on the accurate, rapid and cost-effective detection and interpretation of these biomarkers. miRNAs, which are short noncoding regulatory RNAs, are rapidly emerging as a novel class of biomarkers with a unique set of biological and chemical properties that makes them very appealing candidates for theranostic applications in cancer. Since the utility of some protein-encoding gene biomarkers is already exploited in routine clinical practice, it will be important to identify areas in which miRNAs provide complementary or superior information to these existing (and other translational) biomarkers to enhance the diagnostic, prognostic and predictive power of molecular characterization of tumors. In this article, the challenges and opportunities for integration of miRNA-based assays in the clinical toolkit to improve care and management of patients afflicted with solid tumors will be discussed.