Circulating microRNAs in serum of human K-ras oncogene transgenic rats with pancreatic ductal adenocarcinomas

The Roles of MicroRNA in Pancreatic Cancer Progression

Pancreatic Ductal Adenocarcinoma (PDAC) has a poor patient survival rate in comparison with other cancer types, even after targeted therapy, chemotherapy, and immunotherapy. Therefore, a great deal needs to be done to gain a better understanding of the biology and identification of prognostic and predictive markers for the development of superior therapies. The microRNAs (miRNAs) belong to small non-coding RNAs that regulate post-transcriptional gene expression. Several shreds of evidence indicate that miRNAs play an important role in the pathogenesis of pancreatic cancer. Here we review the recent developments in miRNAs and their target role in the development, metastasis, migration, and invasion.

miR-370 is better than miR-375 as a non-invasive diagnostic biomarker for pediatric acute myeloid leukemia patients

BACKGROUND: Acute myeloid leukemia (AML) is characterized by heterogeneity in phenotypic, genotypic, and clinical traits. miRNAs play an important role in pathogenesis and diagnosis of adult AML. Such information is not available about miRNA expression role in pediatric AML. OBJECTIVE: We aimed to investigate the expression of miR-370 and miR-375 as new diagnostic biomarkers to discriminate pediatric AML patients and to predict their roles in the disease molecular basis. METHODS: The expression of both miR-370 and miR-375 in peripheral blood (PB) of pediatric AML patients was assessed by QPCR; their impact for diagnosis was evaluated by ROC curve and their roles in pediatric AML development were predicted by bioinformatics analysis. RESULTS: The expression of miR-370 and miR-375 levels were significantly decreased in pediatric AML patients, suggesting them as tumor suppressor miRNAs as supported by bioinformatics analysis. MiR-370 showed better potential and sensitivity toscreen pediatric AML patients and more significant correlation with AML risk than miR-375. This is the first study to report the positive correlation between both miR-370 and miR-375. CONCLUSION: miR-370 level in peripheral blood can serve as a potential non-invasive diagnostic biomarker and was significantly correlated with AML risk. We strongly recommend PB miRNAs as diagnostic biomarkers for pediatric AML.

The Role of microRNA in Pancreatic Cancer

MicroRNAs (miRNAs) are small ribonucleic acid molecules that play a key role in regulating gene expression. The increasing number of studies undertaken on the functioning of microRNAs in the tumor formation clearly indicates their important potential in oncological therapy. Pancreatic cancer is one of the deadliest cancers. The expression of miRNAs released into the bloodstream appears to be a good indicator of progression and evaluation of the aggressiveness of pancreatic cancer, as indicated by studies. The work reviewed the latest literature on the importance of miRNAs for pancreatic cancer development.

MicroRNA-31 Regulates Expression of Wntless in Both Drosophila melanogaster and Human Oral Cancer Cells

Recent comparative studies have indicated distinct expression profiles of short, non-coding microRNAs (miRNAs) in various types of cancer, including oral squamous cell carcinoma (OSCC). In this study, we employed a hybrid approach using Drosophila melanogaster as well as OSCC cell lines to validate putative targets of oral cancer-related miRNAs both in vivo and in vitro. Following overexpression of Drosophila miR-31, we found a significant decrease in the size of the imaginal wing discs and downregulation of a subset of putative targets, including wntless (wls), an important regulator of the Wnt signaling pathway. Parallel experiments performed in OSCC cells have also confirmed a similar miR-31-dependent regulation of human WLS that was not initially predicted as targets of human miR-31. Furthermore, we found subsequent downregulation of cyclin D1 and c-MYC, two of the main transcriptional targets of Wnt signaling, suggesting a potential role of miR-31 in regulating the cell cycle and proliferation of OSCC cells. Taken together, our Drosophila-based in vivo system in conjunction with the human in vitro platform will thus provide a novel insight into a mammal-to-Drosophila-to-mammal approach to validate putative targets of human miRNA and to better understand the miRNA-target relationships that play an important role in the pathophysiology of oral cancer.

Clinical Significance of Circulating miR-1273g-3p and miR-122-5p in Pancreatic Cancer

The burden of pancreatic cancer (PanC) requires innovation in the current diagnostic approach. This study aimed to uncover new circulating microRNAs (miRNAs) that would distinguish patients with PanC from healthy subjects (HS) compared with the cancer antigen 19-9 (CA 19-9), and predict patients' clinical phenotypes and outcomes. MiRNA expression profiles in plasma were investigated by using a two-stage process. In a discovery phase, miRNAs levels were analyzed using the GeneChip™ miRNA 4.0 Affymetrix assay in 10 pools of plasma samples from PanC patients and HS; in a validation phase, significantly altered miRNAs were re-tested in independent cohorts of cancer patients and controls by droplet digital PCR (ddPCR). The diagnostic performance of the resulting miRNAs was compared to CA 19-9 determinations, and the associations of miRNAs plasma levels with patients' clinical phenotypes and outcomes were also taken into account. Bioinformatics selection of miRNAs differentially expressed in plasma uncovered miR-18a-5p, miR-122-5p, miR-1273g-3p, and miR-6126 as candidate oncogenic miRNAs in PanC. The ddPCR technology confirmed the significant over-expression of miR-122-5p, miR-1273g-3p, and miR-6126 in PanC compared to HS, in line with the trend of the CA 19-9 levels. Plasma levels of miR-1273g-3p, in combination with CA 19-9, showed higher power in distinguishing PanC patients from HS compared to the CA 19-9 tested alone, with a gain in both sensitivity and negative predictive value indicating a low false-negative rate (SE = 90.2% and NPV = 92.3% vs. SE = 82.1% and NPV = 87.9%). None of the oncogenic miRNAs were able to distinguish between a neoplastic and a proliferative/inflammatory disease of the pancreas, and were not able to stratify subjects according to the clinical risk for the disease. The only valuable association in PanC patients was found between miR-1273g-3p and tumor stage, and increased miR-122-5p levels emerged as independent negative prognostic factor for PanC patients (HR = 1.58, 95% CI = 1.03–2.43, p = 0.037). Our data highlighted a role for circulating miR-1273g-3p and miR-122-5p as new diagnostic and prognostic biomarkers for PanC.

Evaluation of a biomarker for the diagnosis of pancreas cancer using an animal model

Many approaches have been taken to identify new biomarkers of pancreatic ductal carcinoma (PDC). Since animal models can be sampled under controlled conditions, better standardization is possible compared with heterogeneous human studies. Transgenic rats with conditional activation of oncogenic RAS in pancreatic tissue develop PDC that closely resembles the biological and histopathological features of human PDC. Using this model, we evaluated the usefulness of leucine-rich α2-glycoprotein-1 (LRG-1) as a serum marker. In this study, we found that LRG-1 was overexpressed in rat PDC compared with normal pancreas tissue of the control rats. Serum levels of LRG-1 were also significantly higher in rats bearing PDC than in controls. Importantly, chronic pancreatitis in male Wistar Bonn/Kobori rats, which is a widely accepted as a model of chronic pancreatitis, did not cause serum levels of LRG-1 to become elevated. These results strongly support serum LRG-1 as a candidate biomarker for noninvasive diagnosis of PDC. Our models of pancreas cancer provide a useful strategy for evaluation of candidate markers applicable to human cancer.

Clinical Implication of MicroRNAs in Molecular Pathology: An Update for 2018

MicroRNAs (miRNAs) are poised to provide diagnostic, prognostic, and therapeutic targets for several diseases including malignancies for precision medicine applications. The miRNAs have immense potential in the clinical arena because they can be detected in the blood, serum, tissues (fresh and formalin-fixed paraffin-embedded), and fine-needle aspirate specimens. The most attractive feature of miRNA-based therapy is that a single miRNA could be useful for targeting multiple genes that are deregulated in cancers, which can be further investigated through systems biology and network analysis that may provide cancer-specific personalized therapy.

Expression profiling and microRNA regulation of the LKB1 pathway in young and aged lung adenocarcinoma patients

Lung cancer in young patients appears to have distinct clinicopathological features. The present study focused on the role of the serine/threonine kinase liver kinase B1 (LKB1), a known tumor suppressor gene, and its miRNA regulation in lung adenocarcinoma, particularly in young versus elderly patients. A total of 88 patients with lung adenocarcinoma were retrospectively analysed. A simultaneous quantification was performed of the expression of LKB1 mRNA and 15 microRNAs (miRNA/miRs; miRs −93, −96, −34a, −34c, −214, −33a, −30b, −145, −182, −30c, −183, −29b, −29c, −153 and −138) involved in the LKB1 pathway, as well as of 5 identified target mRNAs [cyclin D1 (CCND1), catenin β-1 (CTNNB1), lysyl oxidase (LOX), yes-associated protein 1 (YAP1) and survivin], using NanoString technology. KRAS mutations were investigated by pyrosequencing analysis. Patients ≤50 years were defined as a younger group, while patients >50 years old as an older group (n=44/group). No difference between the two groups was identified in terms of survival times analysed using the Kaplan-Meier method or KRAS mutations. Subsequently, the LKB1 signalling pathway was focused on, as a target for therapy in lung adenocarcinoma, and assessed with regards to clinicopathological features; we found that LOX levels in adenocarcinoma patients were significantly associated with histological subtype (P=0.03), stage (P<0.0001) and prognosis (P=0.02 for disease-free interval and P=0.005 for overall survival), but not with age. Furthermore, the miRNA target prediction model indicated that miR-93 and miR-30b appeared to have functional binding sites and downregulate the gene expression of LKB1 and LOX, respectively. In conclusion, young patients appeared have similar survival rates to elderly patients. The assessment of LKB1, its downstream genes and its regulation by miRNAs may have an impact on future research on lung adenocarcinoma in young and elderly patients. Further investigations will be necessary to elucidate the potential of this pathway as a novel target for therapy.

A Five-microRNA Signature for Survival Prognosis in Pancreatic Adenocarcinoma based on TCGA Data

Novel biomarkers for pancreatic adenocarcinoma are urgently needed because of its poor prognosis. Here, by using The Cancer Genome Atlas (TCGA) RNA-seq data, we evaluated the prognostic values of the differentially expressed miRNAs and constructed a five-miRNA signature that could effectively predict patient overall survival (OS). The Kaplan-Meier overall survival curves of two groups based on the five miRNAs were notably different, showing overall survival in 10.2% and 47.8% at five years for patients in high-risk and low-risk groups, respectively. The ROC curve analysis achieved AUC of 0.775, showing good sensitivity and specificity of the five-miRNA signature model in predicting pancreatic adenocarcinoma patient survival risk. The functional enrichment analysis suggested that the target genes of the miRNA signature may be involved in various pathways related to cancer, including PI3K-Akt, TGF-β, and pluripotent stem cell signaling pathways. Finally, we analyzed expression of the five specific miRNAs in the miRNA signature, and validated the reliability of the results in 20 newly diagnosed pancreatic adenocarcinoma patients using qRT-PCR. The expression results of qRT-PCR were consistent with the TCGA results. Taken together, these findings suggested that the five-miRNA signature (hsa-miR-203, hsa-miR-424, hsa-miR-1266 hsa-miR-1293, and hsa-miR-4772) could be used as a prognostic marker for pancreatic adenocarcinoma.

The role of miRNAs in the diagnosis, chemoresistance, and prognosis of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a very challenging malignancy with late presentation, metastatic potential, chemoresistance, and poor prognosis. Therefore, there is an urgent need for novel diagnostic and prognostic biomarkers. miRNAs are small noncoding RNAs that regulate the expression of multitude number of genes. Aberrant expression of miRNAs has been linked to the development of various malignancies, including PDAC. A series of miRNAs have been defined as holding promise for early diagnostics, as indicators of therapy resistance, and even as markers for prognosis in PDAC patients. In this review, we summarize the current knowledge on the role of miRNAs in diagnosis, chemoresistance, and prognosis in PDAC patients.

miR-31 is distinctively overexpressed in primary male extramammary Paget's disease

MicroRNAs (miRNAs) are small noncoding RNAs involved in cancer development. Extramammary Paget's disease (EMPD) is a rare cutaneous malignancy and the role of miRNAs in EMPD remains unknown. Here, we used TaqMan miRNA arrays to characterize miRNA expression profile in EMPD and further validated the candidates by single RT-PCR. Total 12 cases EMPD were involved in this study. Using laser capture micro-dissection technique, we collected EMPD tumor cells (ET, n=12), normal epidermal cells (NE, n=12) and normal apocrine glands cells (NA, n=7). MiRNA arrays from two pairs of ET and corresponding NE showed that miR-375, miR-10b, miR-31, miR-31* were differentially expressed. The single real-time PCR (RT-PCR) further confirmed that miR-375, miR-31 and miR-31* were upregulated in EMPD cells than those of the normal epidermis and apocrine glands. Our preliminary study suggested that these miRNAs could be involved in EMPD development and miR-31 may serve as potential biomarkers of EMPD.

miR-376c promotes carcinogenesis and serves as a plasma marker for gastric carcinoma

Gastric carcinoma is highly prevalent throughout the world. Understanding the pathogenesis of this disease will benefit diagnosis and resolution. Studies show that miRNAs are involved in the tumorigenesis of gastric carcinoma. An initial screening followed by subsequent validation identified that miR-376c is up-regulated in gastric carcinoma tissue and the plasma of patients with the disease. In addition, the urinary level of miR-376c is also significantly increased in gastric carcinoma patients. The plasma miR-376c level was validated as a biomarker for gastric carcinoma, including early stage tumors. The induction of miR-376c was found to enrich the proliferation, migration and anchorage-independent growth of carcinoma cells and, furthermore, the repression of the expression of endogenous miR-376c was able to reduce such oncogenic phenotypes. ARID4A gene is a direct target of miR-376c. Knockdown of endogenous ARID4A increased the oncogenicity of carcinoma cells, while ARID4A was found to be drastically down-regulated in tumor tissue. Thus, expression levels of miR-376c and ARID4A mRNA tended to be opposing in tumor tissue. Our results demonstrate that miR-376c functions by suppressing ARID4A expression, which in turn enhances the oncogenicity of gastric carcinoma cells. It seems likely that the level of miR-376c in plasma and urine could act as invaluable markers for the detection of gastric carcinoma.

MicroRNA Expression Patterns of CD8+ T Cells in Acute and Chronic Brucellosis

Although our knowledge about Brucella virulence factors and the host response increase rapidly, the mechanisms of immune evasion by the pathogen and causes of chronic disease are still unknown. Here, we aimed to investigate the immunological factors which belong to CD8+ T cells and their roles in the transition of brucellosis from acute to chronic infection. Using miRNA microarray, more than 2000 miRNAs were screened in CD8+ T cells of patients with acute or chronic brucellosis and healthy controls that were sorted from peripheral blood with flow cytometry and validated through qRT-PCR. Findings were evaluated using GeneSpring GX (Agilent) 13.0 software and KEGG pathway analysis. Expression of two miRNAs were determined to display a significant fold change in chronic group when compared with acute or control groups. Both miRNAs (miR-126-5p and miR-4753-3p) were decreased (p <0.05 or fold change > 2). These miRNAs have the potential to be the regulators of CD8+ T cell-related marker genes for chronic brucellosis infections. The differentially expressed miRNAs and their predicted target genes are involved in MAPK signaling pathway, cytokine-cytokine receptor interactions, endocytosis, regulation of actin cytoskeleton, and focal adhesion indicating their potential roles in chronic brucellosis and its progression. It is the first study of miRNA expression analysis of human CD8+ T cells to clarify the mechanism of inveteracy in brucellosis.

In Silico Study of miRNA Based Gene Regulation, Involved in Solid Cancer, by the Assistance of Argonaute Protein

Solid tumor is generally observed in tissues of epithelial or endothelial cells of lung, breast, prostate, pancreases, colorectal, stomach, and bladder, where several genes transcription is regulated by the microRNAs (miRNAs). Argonaute (AGO) protein is a family of protein which assists in miRNAs to bind with mRNAs of the target genes. Hence, study of the binding mechanism between AGO protein and miRNAs, and also with miRNAs-mRNAs duplex is crucial for understanding the RNA silencing mechanism. In the current work, 64 genes and 23 miRNAs have been selected from literatures, whose deregulation is well established in seven types of solid cancer like lung, breast, prostate, pancreases, colorectal, stomach, and bladder cancer. In silico study reveals, miRNAs namely, miR-106a, miR-21, and miR-29b-2 have a strong binding affinity towards PTEN, TGFBR2, and VEGFA genes, respectively, suggested as important factors in RNA silencing mechanism. Furthermore, interaction between AGO protein (PDB ID-3F73, chain A) with selected miRNAs and with miRNAs-mRNAs duplex were studied computationally to understand their binding at molecular level. The residual interaction and hydrogen bonding are inspected in Discovery Studio 3.5 suites. The current investigation throws light on understanding miRNAs based gene silencing mechanism in solid cancer.

Feasibility of urinary microRNA profiling detection in intrahepatic cholestasis of pregnancy and its potential as a non-invasive biomarker

Intrahepatic cholestasis of pregnancy (ICP), a pregnancy-related liver disease, leads to complications for both mother and fetus. Circulating microRNAs (miRNAs) have emerged as candidate biomarkers for many diseases. So far, the circulating miRNAs profiling of ICP has not been investigated. To assess the urinary miRNAs as non-invasive biomarkers for ICP, a differential miRNA profiling was initially analyzed by individual quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assay in urinary samples from a screening set including 10 ICP and 10 healthy pregnancies. The selected candidate miRNAs were then validated by a validation set with 40 ICP and 50 healthy pregnancies using individual qRT-PCR assay. Compared with the expression in urine of healthy pregnant women, the expression levels of hsa-miR-151-3p and hsa-miR-300 were significantly down-regulated, whereas hsa-miR-671-3p and hsa-miR-369-5p were significantly up-regulated in urine from ICP patients (p < 0.05 and false discovery rate < 0.05). A binary logistic regression model was constructed using the four miRNAs. The area under the receiver operating characteristic curve was 0.913 (95% confidence interval = 0.847 to 0.980; sensitivity = 82.9%, specificity = 87.0%). Therefore, urinary microRNA profiling detection in ICP is feasible and maternal urinary miRNAs have the potential to be non-invasive biomarkers for the diagnosis of ICP.

MiR-541-3p reverses cancer progression by directly targeting TGIF2 in non-small cell lung cancer

Lung cancer remains a leading cause of cancer-associated mortality worldwide, and non-small lung cancer (NSCLC) is responsible for over 80 % of lung cancer-related deaths. Identifying novel molecular biomarker that can inhibit the progression of lung cancer will facilitate the development of new treatment strategies. Herein, we demonstrated that miR-541-3p is a tumor-suppressor microRNA (miRNA) in NSCLC progression. We found that expression of miR-541-3p was decreased obviously in NSCLC tissues and plasma. Down-regulation of miR-541-3p was associated with TNM stage and postoperative survival. Overexpression of miR-541-3p inhibited the growth and metastasis of NSCLC cells. The TGIF2 was a direct target of miR-541-3p and promoted the growth and metastasis of NSCLC cells. Further study showed that TGIF2 could reverse the inhibitory effect of miR-541-3p on growth and metastasis of NSCLC cells. Taken together, our data highlight the pivotal role of miR-541-3p in the progression of NSCLC. Thus, miR-541-3p may be a potential prognostic marker and of treatment relevance for NSCLC progression intervention.

Expression of microRNAs in fibroblast of pterygium

AIM

To screen microRNAs (miRNAs) and set up target miRNAs in pterygium.

METHODS

Primary fibroblasts were isolated from pterygium and Tenon's capsule and cultured. Immunocytochemical analysis and Western blotting were performed to confirm the culture of fibroblasts. In all, 1733 miRNAs were screened in the first step by using GeneChip(®) miRNA3.0 Array. Specific miRNAs involved in the pathogenesis of pterygium were subsequently determined using the following criteria: 1) high reproducibility in a repetitive test; 2) base log value of >7.0 for both control and pterygial fibroblasts; and 3) log ratio of >1.0 between pterygial fibroblasts and control fibroblasts.

RESULTS

Primary screening showed that 887/1733 miRNAs were up-regulated and 846/1733 miRNAs were down-regulated in pterygial fibroblasts compared with those in control fibroblasts. Of the 1733 miRNAs screened, 4 miRNAs, namely, miRNA-143a-3p, miRNA-181a-2-3p, miRNA-377-5p and miRNA-411a-5p, met the above-mentioned criteria. Primary screening showed that these 4 miRNAs were up-regulated in pterygial fibroblasts compared with control fibroblasts and that miRNA-143a-3p had the highest mean ratio compared with the miRNAs in control fibroblasts.

CONCLUSION

miRNA-143a-3p, miRNA-181a-2-3p, miRNA-377-5p and miRNA-411a-5p are up-regulated in pterygial fibroblasts compared with control fibroblasts, suggesting their involvement in the pathogenesis of pterygium.

The altered microRNA profile in andrographolide-induced inhibition of hepatoma tumor growth

BACKGROUND

MicroRNAs (miRNAs) have been reported to play critical roles in regulating gene expression in tumor development. Natural compound andrographolide (Andro), isolated from medicinal herb Andrographis paniculata, was reported to inhibit hepatoma tumor growth in our previous studies. The present study aims to observe the altered miRNAs profile and related signaling pathways involved in Andro-induced inhibition on hepatoma tumor growth.

RESULTS

The inhibition on hepatoma tumor growth induced by Andro (10mg/kg) was found in a xenograft mouse tumor model in vivo. The results of miRNAs chip analysis showed that the expression of 22 miRNAs was increased, whereas the expression of other 10 miRNAs was decreased after Andro treatment. Further, the increased expression of miR-222-3p, miR-106b-5p, miR-30b-5p, and miR-23a-5p was confirmed in hepatoma Hep3B and SMCC7721 cells in vitro after cells were treated with Andro (50μM) for the indicated time. Functional annotation of the target genes based on the differentially expressed miRNAs demonstrated that the majority of the genes were involved in a variety of signaling pathways, including miRNAs in cancer, mitogen-activated protein kinases (MPAKs), focal adhesion. Furthermore, the expression of 24 target genes (total 31) involved in above signaling pathways based on miRNAs analysis was found to be consistent with the alteration of miRNAs.

CONCLUSIONS

The results demonstrate that Andro alters the expression of miRNAs profile and downstream signals, which may contribute to its inhibition on hepatoma tumor growth.

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.

Circulating RNAs as new biomarkers for detecting pancreatic cancer

Pancreatic cancer remains difficult to treat and has a high mortality rate. It is difficult to diagnose early, mainly due to the lack of screening imaging modalities and specific biomarkers. Consequently, it is important to develop biomarkers that enable the detection of early stage tumors. Emerging evidence is accumulating that tumor cells release substantial amounts of RNA into the bloodstream that strongly resist RNases in the blood and are present at sufficient levels for quantitative analyses. These circulating RNAs are upregulated in the serum and plasma of cancer patients, including those with pancreatic cancer, compared with healthy controls. The majority of RNA biomarker studies have assessed circulating microRNAs (miRs), which are often tissue-specific. There are few reports of the tumor-specific upregulation of other types of small non-coding RNAs (ncRNAs), such as small nucleolar RNAs and Piwi-interacting RNAs. Long ncRNAs (lncRNAs), such as HOTAIR and MALAT1, in the serum/plasma of pancreatic cancer patients have also been reported as diagnostic and prognostic markers. Among tissue-derived RNAs, some miRs show increased expression even in pre-cancerous tissues, and their expression profiles may allow for the discrimination between a chronic inflammatory state and carcinoma. Additionally, some miRs and lncRNAs have been reported with significant alterations in expression according to disease progression, and they may thus represent potential candidate diagnostic or prognostic biomarkers that may be used to evaluate patients once detection methods in peripheral blood are well established. Furthermore, recent innovations in high-throughput sequencing techniques have enabled the discovery of unannotated tumor-associated ncRNAs and tumor-specific alternative splicing as novel and specific biomarkers of cancers. Although much work is required to clarify the release mechanism, origin of tumor-specific circulating RNAs, and selectivity of carrier complexes, and technical advances must also be achieved, such as creating a consensus normalization protocol for quantitative data analysis, circulating RNAs are largely unexplored and might represent novel clinical biomarkers.

In vivo18F-fluorodeoxyglucose-positron emission tomography/computed tomography imaging of pancreatic tumors in a transgenic rat model carrying the human KRASG12V oncogene

A novel KRAS-mediated transgenic rat model has previously been demonstrated, in which animals develop multiple pancreatic ductal adenocarcinoma (PDAC) that is histologically similar to human PDAC within two weeks. Positron emission tomography (PET)/computed tomography (CT) is commonly used for the diagnosis and staging of PDAC in humans, and can be adopted for optimal use in animal experiments. The aim of the present study was to evaluate the carcinogenic process in a rat pancreatic carcinoma model using small-animal multimodality imaging systems. The utility of fluorodeoxyglucose (FDG)-PET/CT in detecting the location and size of PDAC during tumor development in the present transgenic rat model was assessed. A small animal multimodality PET/CT system and contrast-enhanced CT (CECT) system were used for the imaging analysis of KRAS^G12V male transgenic rats (n=6), which developed pancreatic tumors following the administration of an injection of Cre recombinase (Cre)-carrying adenovirus. Laparotomies performed at six weeks post-treatment revealed that all three (100%) Cre-expressing rats developed pancreatic tumors that were <2 mm in diameter, none of which were detected by ¹⁸F-FDG PET/CT or CECT. At eight weeks post-treatment, the pancreatic tumors were heterogeneously visualized by ¹⁸F-FDG-PET/CT and CECT in two of the three rats. Furthermore, the autopsies confirmed that all three rats had developed pancreatic tumors. These novel findings provide evidence that the FDG-PET/CT imaging system is a valuable tool for the evaluation of the carcinogenic process, and one which may aid in treatment and preventive methods for pancreatic tumors in mammalian models. A limitation associated with the early detection of PDACs warrants further investigation.

MicroRNAs as potential biomarkers in cancer: opportunities and challenges

MicroRNAs (miRNAs) are a group of small noncoding RNAs (ncRNAs) that posttranscriptionally regulate gene expression by targeting their corresponding messenger RNAs (mRNAs). Dysregulated miRNAs have been considered as a new type of ‘‘oncomiRs” or ‘‘tumor suppressors,” playing essential roles in cancer initiation and progression. Using genome-wide detection methods, ubiquitously aberrant expression profiles of miRNAs have been identified in a broad array of human cancers, showing great potential as novel diagnostic and prognostic biomarkers of cancer with high specificity and sensitivity. The detectable miRNAs in tissue, blood, and other body fluids with high stability provide an abundant source for miRNA-based biomarkers in human cancers. Despite the fact that an increasing number of potential miRNA biomarkers have been reported, the transition of miRNAs-based biomarkers from bench to bedside still necessitates addressing several challenges. In this review, we will summarize our current understanding of miRNAs as potential biomarkers in human cancers.

Clinical implications of miRNAs in the pathogenesis, diagnosis and therapy of pancreatic cancer

Despite considerable progress being made in understanding pancreatic cancer (PC) pathogenesis, it still remains the 10th most often diagnosed malignancy in the world and 4th leading cause of cancer related deaths in the United States with a five year survival rate of only 6%. The aggressive nature, lack of early diagnostic and prognostic markers, late clinical presentation, and limited efficacy of existing treatment regimens make PC a lethal cancer with high mortality and poor prognosis. Therefore, novel reliable biomarkers and molecular targets are urgently needed to combat this deadly disease. MicroRNAs (miRNAs) are short (19-24 nucleotides) non-coding RNA molecules implicated in the regulation of gene expression at post-transcriptional level and play significant roles in various physiological and pathological conditions. Aberrant expression of miRNAs has been reported in several cancers including PC and is implicated in PC pathogenesis and progression, suggesting their utility in diagnosis, prognosis and therapy. In this review, we summarize the role of several miRNAs that regulate various oncogenes (KRAS) and tumor suppressor genes (p53, p16, SMAD4, etc.) involved in PC development, their prospective roles as diagnostic and prognostic markers and as a therapeutic targets.

Rat N-ERC/mesothelin as a marker for in vivo screening of drugs against pancreas cancer

Pancreatic ductal adenocarcinoma (PDA) is a highly lethal disease, which is usually diagnosed in an advanced stage. We have established transgenic rats carrying a mutated K-ras gene controlled by Cre/loxP activation. The animals develop PDA which is histopathologically similar to that in humans. Previously, we reported that serum levels of N-ERC/mesothelin were significantly higher in rats bearing PDA than in controls. In the present study, to determine whether serum levels of N-ERC/mesothelin correlated with tumor size, we measured N-ERC/mesothelin levels in rats bearing PDA. Increased serum levels of N-ERC/mesothelin correlated with increased tumor size. This result indicates an interrelationship between the serum level of N-ERC/mesothelin and tumor size. We next investigated the effect of chemotherapy on serum N-ERC/mesothelin levels. Rat pancreatic cancer cells were implanted subcutaneously into the flank of NOD-SCID mice. In the mice treated with 200 mg/kg gemcitabine, tumor weight and the serum level of N-ERC/mesothelin were significantly decreased compared to controls. These results suggest that serum N-ERC/mesothelin measurements might be useful for monitoring response to therapy.

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.

Emerging role of the KRAS-PDK1 axis in pancreatic cancer

Pancreatic cancer is a highly aggressive tumour that is very resistant to treatments and it is rarely diagnosed early because of absence of specific symptoms. Therefore, the prognosis for this disease is very poor and it has the grim supremacy in terms of unfavourable survival rates. There have been great advances in survival rates for many types of cancers over the past few decades but hardly any change for pancreatic cancer. Mutations of the Ras oncogene are the most frequent oncogenic alterations in human cancers. The frequency of KRAS mutations in pancreatic cancer is around 90%. Given the well-established role of KRAS in cancer it is not surprising that it is one of the most attractive targets for cancer therapy. Nevertheless, during the last thirty years all attempts to target directly KRAS protein have failed. Therefore, it is crucial to identify downstream KRAS effectors in order to develop specific drugs able to counteract activation of this pathway. Among the different signalling pathways activated by oncogenic KRAS, the phosphoinositide 3-Kinase (PI3K) pathway is emerging as one of the most critical KRAS effector. In turn, PI3K activates several parallel pathways making the identification of the precise effectors activated by KRAS/PI3K more difficult. Recent data identify 3-phosphoinositide-dependent protein kinase 1 as a key tumour-initiating event downstream KRAS interaction with PI3K in pancreatic cancer.

Decreased miR-30b-5p expression by DNMT1 methylation regulation involved in gastric cancer metastasis

miRNAs have emerged as crucial regulators in the regulation of development as well as human diseases, especially tumorigenesis. The aims of this study are to evaluate miR-30b-5p expression pattern and mechanism in gastric carcinogenesis due to which remains to be determined. Expression of miR-30b-5p was analyzed in 51 gastric cancer cases and 4 cell lines by qRT-PCR. The effect of DNA methylation on miR-30b-5p expression was assessed by MSP and BGS. In order to know whether DNMT1 increased miR-30b-5p promoter methylation, DNMT1 was depleted in cell lines AGS and BGC-823. The role of miR-30b-5p on cell migration was evaluated by wound healing assays. Decreased expression of miR-30b-5p was found in gastric cancer samples. In tumor, the expression level of miR-30b-5p was profound correlated with lymph node metastasis (P = 0.019). The level of miR-30b-5p may be restored by DNA demethylation and DNMT1 induced miR-30b-5p promoter methylation. In vitro functional assays implied that enforced miR-30b-5p expression affected cell migration, consistent with tissues analysis. Our findings uncovered that miR-30b-5p is significantly diminished in gastric cancer tissues, providing the first insight into the epigenetic mechanism of miR-30b-5p down-regulation, induced by DNMT1, and the role of miR-30b-5p in gastric cancer carcinogenesis. Overexpression of miR-30b-5p inhibited cell migration. Thus, miR-30b-5p may represent a potential therapeutic target for gastric cancer therapy.

Role of abnormal lipid metabolism in development, progression, diagnosis and therapy of pancreatic cancer

There is growing evidence that metabolic alterations play an important role in cancer development and progression. The metabolism of cancer cells is reprogrammed in order to support their rapid proliferation. Elevated fatty acid synthesis is one of the most important aberrations of cancer cell metabolism. An enhancement of fatty acids synthesis is required both for carcinogenesis and cancer cell survival, as inhibition of key lipogenic enzymes slows down the growth of tumor cells and impairs their survival. Based on the data that serum fatty acid synthase (FASN), also known as oncoantigen 519, is elevated in patients with certain types of cancer, its serum level was proposed as a marker of neoplasia. This review aims to demonstrate the changes in lipid metabolism and other metabolic processes associated with lipid metabolism in pancreatic ductal adenocarcinoma (PDAC), the most common pancreatic neoplasm, characterized by high mortality. We also addressed the influence of some oncogenic factors and tumor suppressors on pancreatic cancer cell metabolism. Additionally the review discusses the potential role of elevated lipid synthesis in diagnosis and treatment of pancreatic cancer. In particular, FASN is a viable candidate for indicator of pathologic state, marker of neoplasia, as well as, pharmacological treatment target in pancreatic cancer. Recent research showed that, in addition to lipogenesis, certain cancer cells can use fatty acids from circulation, derived from diet (chylomicrons), synthesized in liver, or released from adipose tissue for their growth. Thus, the interactions between de novo lipogenesis and uptake of fatty acids from circulation by PDAC cells require further investigation.

MicroRNA-17, microRNA-18a, and microRNA-19a are prognostic indicators in esophageal squamous cell carcinoma

BACKGROUND

The members of the microRNA (miR)-17-92 cluster have been reported to be highly expressed in several cancers. However, whether their expression is associated with clinicopathologic factors, the prognosis of patients in esophageal squamous cell carcinoma (ESCC) remains unknown.

METHODS

Using SYBR green real-time quantitative reverse transcription polymerase chain reaction, we detected the expression of members of the miR-17-92 cluster, including miR-17, miR-18a, miR-19a, miR-20a, miR-19b, and miR-92a, in 105 surgical specimens from ESCC patients. We then investigated their impact on clinicopathologic factors and survival.

RESULTS

All six members of the miR-17-92 cluster had a significantly higher level of expression in the 105 ESCC tissue specimens than in normal esophageal mucosa (p < 0.05). The miR-18a expression positively correlated with tumor stage (p = 0.025). Meanwhile, miR-92a expression positively correlated with clinical stage (p = 0.022), and miR-19b expression positively correlated with tumor size (p = 0.005), lymph node metastasis (p = 0.040), and clinical stage (p = 0.011). The overexpression of miR-17a was correlated positively with lymph node metastasis (p = 0.035) and clinical stage (p = 0.022). MiR-18a, miR-17, and miR-19a were prognostic indicators for progression-free survival and overall survival. both in univariate analysis and in multivariate analysis.

CONCLUSIONS

This study suggests that miR-17, miR-18a, and miR-19a can serve as potential unfavorable prognostic biomarkers in ESCC which are associated with some clinicopathologic factors. However, the regulatory pathway associated with potential candidate miRNAs remains to be explored.

Comparisons of microRNA patterns in plasma before and after tumor removal reveal new biomarkers of lung squamous cell carcinoma

Lung cancer is the major human malignancy, accounting for 30% of all cancer-related deaths worldwide. Poor survival of lung cancer patients, together with late diagnosis and resistance to classic chemotherapy, highlights the need for identification of new biomarkers for early detection. Among different cancer biomarkers, small non-coding RNAs called microRNAs (miRNAs) are considered the most promising, owing to their remarkable stability, their cancer-type specificity, and their presence in body fluids. However, results of multiple previous attempts to identify circulating miRNAs specific for lung cancer are inconsistent, likely due to two main reasons: prominent variability in blood miRNA content among individuals and difficulties in distinguishing tumor-relevant miRNAs in the blood from their non-tumor counterparts. To overcome these impediments, we compared circulating miRNA profiles in patients with lung squamous cell carcinoma (SCC) before and after tumor removal, assuming that the levels of all tumor-relevant miRNAs would drop after the surgery. Our results revealed a specific panel of the miRNAs (miR-205, -19a, -19b, -30b, and -20a) whose levels decreased strikingly in the blood of patients after lung SCC surgery. Interestingly, miRNA profiling of plasma fractions of lung SCC patients revealed high levels of these miRNA species in tumor-specific exosomes; additionally, some of these miRNAs were also found to be selectively secreted to the medium by cultivated lung cancer cells. These results strengthen the notion that tumor cells secrete miRNA-containing exosomes into circulation, and that miRNA profiling of the exosomal plasma fraction may reveal powerful cancer biomarkers.

Cell-free plasma microRNA in pancreatic ductal adenocarcinoma and disease controls

OBJECTIVES

There are no tumor-specific biochemical markers for pancreatic ductal adenocarcinoma (PDAC). Tissue-specific gene expression including microRNA (miRNA) profiling, however, identifies specific PDAC signatures. This study evaluates associations between circulating, cell-free plasma-miRNA profiles and PDAC in a disease and disease-control cohort.

METHODS

We performed a microarray profiling of 847 different mature miRNAs from plasma in an exploratory cohort of 20 patients with PDAC or other pancreatic diseases, profiling of 45 miRNAs in plasma samples from PDAC (n = 48) and disease controls (n = 47), and evaluation of associations of data with diagnosis, survival, and CA-19-9.

RESULTS

We find 7 significantly deregulated miRNAs in PDAC using univariate statistics. At a false-discovery rate of 5%, miRNA-375 remained significantly elevated in PDAC. MicroRNA-375 did not improve diagnosis of PDAC in this cohort (70% accuracy) and did not correlate with survival. However, 3 controls (other gastrointestinal cancers) with increased CA-19-9 did not show increased miRNA-375.

CONCLUSIONS

In the plasma-miRNA population, we find miRNA-375, which is selectively expressed in the endocrine pancreas under normal conditions, increased in PDAC cases compared with patients with other pancreatic or gastrointestinal diseases. The miRNA-375 does not outperform CA-19-9 diagnostically in the present cohort. However, it shows promising specificity and should be examined in larger prospective studies.

Upregulation of microRNA-375 is associated with poor prognosis in pediatric acute myeloid leukemia

A genome-wide serum miRNA expression analysis previously showed the upregulation of microRNA-375 (miR-375) in acute myeloid leukemia (AML) patients compared with healthy controls. The aim of this study was to investigate the expression patterns and the prognostic relevance of miR-375 in pediatric AML. Expression levels of miR-375 in bone marrow mononuclear cells were detected by real-time quantitative PCR in a cohort of 106 patients with newly diagnosed pediatric AML. Expression levels of miR-375 in the bone marrow of pediatric AML patients were significantly higher than those in normal controls (P < 0.001). Then, miR-375 upregulation occurred more frequently in French-American-British classification subtype M7 than in other subtypes (P < 0.001). Regarding to cytogenetic risk, the expression levels of miR-375 in pediatric AML patients with unfavorable karyotypes were dramatically higher than those in intermediate and favorable groups (P = 0.002). Moreover, high miR-375 expression was significantly associated with shorter relapse-free survival (P < 0.001) and overall survival (P < 0.001) in pediatric AML patients. Multivariate analysis further identified miR-375 expression and cytogenetics risk as independent prognostic factors for both relapse-free survival and overall survival. In particular, the prognostic relevance of miR-375 expression was more obvious in the subgroup of patients with intermediate-risk cytogenetics. Our findings suggest for the first time that the upregulation of miR-375 may be one of the molecular mechanisms involved in the development and progression of pediatric AML. Since its correlation with poor relapse-free survival and overall survival, miR-375 may be a novel biomarker to improve the management of pediatric AML patients.

Circulating peripheral blood mononuclear cells exhibit altered miRNA expression patterns in pancreatic cancer

Evaluation of: Wang WS, Liu LX, Li GP et al. Combined serum CA19-9 and miR-27a-3p in peripheral blood mononuclear cells to diagnose pancreatic cancer. Cancer Prev. Res. (Phila.) 6(4), 331-338 (2013). Patients with pancreatic ductal adenocarcinoma (PDAC) have a bleak outlook, primarily because tumors are detected late and are often too advanced for surgical resection. In addition, these lesions are incredibly resistant to anticancer therapies. The majority of PDAC patients have impaired tumor immunity, contributing to disease development and progression, although the mechanisms remain poorly understood. miRNAs are important negative gene regulators that have critical roles in human tumorigenesis. Blood-based miRNAs have been investigated as biomarkers for various cancers, in the hope that these will outperform current serum tumor markers. The evaluated study examined the miRNA profiles in peripheral blood mononuclear cells from PDAC patients. The theory is that circulating blood cells monitor the patients' physiological state and respond by altering their transcriptome and that this can then be used to detect disease. In this article, we have examined the evidence for using circulating miRNAs to diagnose/prognose PDAC.

TGF-β/Smad2/3 signaling directly regulates several miRNAs in mouse ES cells and early embryos

The Transforming Growth Factor-β (TGF-β) signaling pathway is one of the major pathways essential for normal embryonic development and tissue homeostasis, with anti-tumor but also pro-metastatic properties in cancer. This pathway directly regulates several target genes that mediate its downstream functions, however very few microRNAs (miRNAs) have been identified as targets. miRNAs are modulators of gene expression with essential roles in development and a clear association with diseases including cancer. Little is known about the transcriptional regulation of the primary transcripts (pri-miRNA, pri-miR) from which several mature miRNAs are often derived. Here we present the identification of miRNAs regulated by TGF-β signaling in mouse embryonic stem (ES) cells and early embryos. We used an inducible ES cell system to maintain high levels of the TGF-β activated/phosphorylated Smad2/3 effectors, which are the transcription factors of the pathway, and a specific inhibitor that blocks their activation. By performing short RNA deep-sequencing after 12 hours Smad2/3 activation and after 16 hours inhibition, we generated a database of responsive miRNAs. Promoter/enhancer analysis of a subset of these miRNAs revealed that the transcription of pri-miR-181c/d and the pri-miR-341∼3072 cluster were found to depend on activated Smad2/3. Several of these miRNAs are expressed in early mouse embryos, when the pathway is known to play an essential role. Treatment of embryos with TGF-β inhibitor caused a reduction of their levels confirming that they are targets of this pathway in vivo. Furthermore, we showed that pri-miR-341∼3072 transcription also depends on FoxH1, a known Smad2/3 transcription partner during early development. Together, our data show that miRNAs are regulated directly by the TGF-β/Smad2/3 pathway in ES cells and early embryos. As somatic abnormalities in functions known to be regulated by the TGF-β/Smad2/3 pathway underlie tumor suppression and metastasis, this research also provides a resource for miRNAs involved in cancer.

Correlation of microRNA-375 downregulation with unfavorable clinical outcome of patients with glioma

BACKGROUND AND AIM

MicroRNA-375 (miR-375) is frequently demonstrated to be frequently dysregulated and functions as a tumor suppressor or an oncogene in different cancer types. However, its roles in human gliomas have not been reported. The aim of this study was to investigate the expression pattern and clinical significance of miR-375 in patients with gliomas.

METHODS

Real-time quantitative RT-PCR assay was performed to detect miR-375 expression in human gliomas and non-neoplastic brain tissues. Then, the association of miR-375 expression with clinicopathological factors and prognosis of glioma patients was also statistically analyzed.

RESULTS

miR-375 expression was significantly decreased on average in glioma tissues relative to non-neoplastic brain tissues (P<0.0001) with ascending pathological grade. Then, the low miR-375 expression in glioma tissues was significantly associated with advanced pathological grade (P=0.003) and low Karnofsky performance score (KPS, P=0.01). Moreover, both univariate and multivariate Cox regression analyses determined that loss of miR-375 expression effectively predicted the decreased overall survival in patients with gliomas.

CONCLUSIONS

These findings offer the first convinced evidence that the downregulation of miR-375 expression in human gliomas may play an inhibitory role during the tumor development. This miRNA might function as a candidate unfavorable prognostic marker for human gliomas.

Neurotensin and its high affinity receptor 1 as a potential pharmacological target in cancer therapy

Cancer is a worldwide health problem. Personalized treatment represents a future advancement for cancer treatment, in part due to the development of targeted therapeutic drugs. These molecules are expected to be more effective than current treatments and less harmful to normal cells. The discovery and validation of new targets are the foundation and the source of these new therapies. The neurotensinergic system has been shown to enhance cancer progression in various cancers such as pancreatic, prostate, lung, breast, and colon cancer. It also triggers multiple oncogenic signaling pathways, such as the PKC/ERK and AKT pathways. In this review, we discuss the contribution of the neurotensinergic system to cancer progression, as well as the regulation and mechanisms of the system in order to highlight its potential as a therapeutic target, and its prospect for its use as a treatment in certain cancers.