MicroRNA-10b is overexpressed in pancreatic cancer, promotes its invasiveness, and correlates with a poor prognosis

Effects of microRNA-183 on epithelial-mesenchymal transition, proliferation, migration, invasion and apoptosis in human pancreatic cancer SW1900 cells by targeting MTA1

OBJECTIVE

This study aims to explore effects of miR-183 on epithelial-mesenchymal transition (EMT) and invasion by targeting MTA1 in human pancreatic cancer (PC) cells.

METHODS

Totally, 108 PC patients admitted in Wenzhou Central Hospital and Wenzhou People's Hospital, The Dingli Clinical Institute of Wenzhou Medical University from March 2010 to March 2014 were enrolled. qRT-PCR and immunohistochemistry were applied to examine expression of MTA1 mRNA and protein. Samples were divided into 6 groups: blank, NC, miR-183 mimics, miR-183 inhibitors, MTA1-siRNA and miR-183 inhibitors +MTA1-siRNA groups. CCK8 method was employed for determining cell proliferation rate, flow cytometry for cell apoptosis rate, scratch test for cell migration and Transwell assay for cell invasion. qRT-PCR and Western blotting were used to determine expression of MTA1, E-cadherin and Vimentin mRNA and protein.

RESULTS

Positive expression rate of MTA1 was upregulated in PC tissues, and expression of miR-183 and MTA1 was associated with differentiation, migration, tumor size, TNM. The miR-183 mimics and MTA1-siRNA groups showed a decrease in proliferation, migration and invasion, whereas increased apoptosis, in comparison with blank and NC groups, as expression of MTA1 and Vimentin mRNA and protein were reduced, expression of E-cadherin mRNA and protein was elevated. Compared to blank and NC groups, the miR-183 inhibitors group exhibited enhanced proliferation, migration and invasion and inhibited apoptosis; increased expressions of MTA1 and Vimentin mRNA and protein and decreased expressions of E-cadherin mRNA and protein.

CONCLUSION

Our study supported that miR-183 could repress EMT and invasion of human PC cells through inhibition of MTA1 expression.

Never let it go: Stopping key mechanisms underlying metastasis to fight pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive neoplasm, predicted to become the second leading cause of cancer-related deaths before 2030. This dismal trend is mainly due to lack of effective treatments against its metastatic behavior. Therefore, a better understanding of the key mechanisms underlying metastasis should provide new opportunities for therapeutic purposes. Genomic analyses revealed that aberrations that fuel PDAC tumorigenesis and progression, such as SMAD4 loss, are also implicated in metastasis. Recently, microRNAs have been shown to play a regulatory role in the metastatic behavior of many tumors, including PDAC. In particular, miR-10 and miR-21 have appeared as master regulators of the metastatic program, while members of the miR-200 family are involved in the epithelial-to-mesenchymal switch, favoring cell migration and invasiveness. Several studies have also found a close relationship between cancer stem cells (CSCs) and biological features of metastasis, and the CSC markers ALDH1, ABCG2 and c-Met are expressed at high levels in metastatic PDAC cells. Emerging evidence reveals that exosomes are involved in the modulation of the tumor microenvironment and can initiate PDAC pre-metastatic niche formation in the liver and lungs. In this review, we provide an overview of the role of all these pivotal factors in the metastatic behavior of PDAC, and discuss their potential exploitation in the clinic to improve current therapeutics and identify new drug targets.

MicroRNA-10b mediates TGF-β1-regulated glioblastoma proliferation, migration and epithelial-mesenchymal transition

Although it is well known that exaggerated proliferation, metastasis and the mesenchymal subtype is related with worst prognoses in glioblastoma (GBM) and that transforming growth factor-β1 (TGF-β1) is a potent factor in regulating the proliferation, migration and epithelial-mesenchymal transition (EMT) phenotype of GBM, the detailed mechanisms are still far from elucidated. MicroRNAs (miRNAs) are small non-coding RNAs which play critical roles in various diseases by regulating target gene expression. We report that miR-10b, a molecule downstream of TGF-β1, is involved in TGF-β1-regulated GBM cell proliferation, migration and EMT. We found that exposure of GBM cells to TGF-β1 significantly upregulated miR-10b expression. Overexpression of miR-10b promotes GBM cell proliferation, migration and EMT, whereas depletion of miR-10b obtained reverse effects. Further studies uncovered that some tumor-associated genes including epithelial cadherin (E-cadherin), apoptotic protease activating factor 1 (Apaf-1) and phosphatase and tensin homolog (PTEN) are target genes of miR-10b. In human GBM xenografts, antagomiR directed against miR-10b markedly suppressed tumor growth, and the tumor volume shrunk from 1252.5±285 to 873.4±205 mm3 after antagomiR‑10b treatment for 3 weeks compared with the control group (P<0.01). Taken together, our data collectively demonstrate that the proliferation, migration and EMT features of GBM cells can be regulated by TGF-β1 stimulation through controlling miR-10b. Thus, our findings provide a rationale for targeting TGF-β1 or miR-10b for the treatment of GBM.

An Explorative Analysis for the Role of Serum miR-10b-3p Levels in Predicting Response to Sorafenib in Patients with Advanced Hepatocellular Carcinoma

The prognostic role of aberrant serum miRNA expression for predicting response to sorafenib treatment in advanced hepatocellular carcinoma (HCC) patients has not been well characterized. We aimed to identify specific serum miRNAs that are associated with positive radiologic responses or improved survival in sorafenib-treated HCC patients. miR-18a, miR-21, miR-139-5p, miR-221, miR-224, and miR-10b-3p, were selected for analysis. Serum samples from 24 patients with advanced stage HCC and 25 patients with liver cirrhosis (LC) were analyzed. All of the miRNAs except miR-21 were found to be upregulated in serum samples from HCC patients. None of the miRNAs assayed differed significantly in terms of expression between the responder and non-responder groups among HCC patients. However, miR-10b-3p levels were significantly higher in the subgroup of HCC patients with worse overall survival (fold change = 5.8, P = 0.008). Serum miRNA-10b-3p was upregulated in the presence of macrovascular invasion (MVI), and those with higher serum miRNA-10b-3p had significantly shorter survival during treatment (P = 0.042). Although no single serum miRNA was predictive of response to sorafenib treatment, analysis of serum miR-10b-3p levels may be valuable for diagnosis of HCC and prediction of survival of sorafenib-treated patients.

miR-10b, miR-26a, miR-146a And miR-153 Expression in Triple Negative Vs Non Triple Negative Breast Cancer: Potential Biomarkers

MicroRNAs (miRNAs) are small non-coding RNAs composed of 18-25 nucleotides that can post-transcriptionally regulate gene expression and have key regulatory roles in cancer, acting as both oncogenes and tumor suppressors. About 1000 genes in humans encode miRNAs, which account for approximately 3% of the human genome, and up to 30% of human protein coding genes may be regulated by miRNAs. The objective of this article is to evaluate the expression profile of four miRNAs previously implicated in triple negative breast cancer: miR-10b, miR-26a, miR-146a and miR-153, and to determine their possible interaction in triple negative and non triple negative breast cancer based on clinical outcome and the expression of BRCA1. 24 triple-negative and 13 non triple negative breast cancer cases, were studied by q-RT-PCR and immunohistochemistry to determine the expression of the four studied miRNAs and the BRCA1 protein, respectively. We observed that the BRCA1 protein was absent in 62.5% of the triple negative cases. Besides, the miR-146a and miR-26a were over expressed in triple negative breast cancer. These two miRNAs, miR-10b and miR-153 were significantly associated to lymph node metastases occurrence in triple negative breast carcinoma. All the analyzed microRNAs were not associated with the expression of BRCA1 in our conditions. Our work provides evidence that miR-146a, miR-26a, miR-10b and miR-153 could be defined as biomarkers in triple negative breast cancer to predict lymph node metastases (LNM).

Role of miR-15a in intervertebral disc degeneration through targeting MAP3K9

BACKGROUND

Accumulating evidence indicates that microRNAs are involved in various cellular processes, including cell proliferation, differentiation, apoptosis and metastasis. miR-15a is an important regulator of immune responses and angiogenesis, endogenous controls as well as potential targets and hallmarks of cancer. However, the role of miR-15a in intervertebral disc degeneration (IDD) has not been elucidated.

METHODS

Total RNA was extracted from degenerative nucleus pulposus (NP) tissues of 20 patients with IDD and NP cells, respectively. The expression levels of miR-15a were examined by quantitative real-time PCR. The stable overexpress or silence miR-15a expression cell lines and control cell lines were constructed by lentivirus infection. Subsequently, 3-(4,5-dimethylthia zol-2-yl)-2,5-diphenylte trazolium bromide (MTT) assay, flow cytometry test, TdT-mediated dUTP Nick-End Labeling (TUNEL) experiment, colony formation assay and western blot analysis were performed to detect the biological functions of miR-15a. Moreover, a luciferase reporter assay was conducted to confirm its target associations.

RESULTS

Herein, the results found that miR-15a was dramatically up-regulated in degenerative NP tissues and NP cells compared with the controls. Overexpression of miR-15a promoted NP cells proliferation and induced apoptosis. Moreover, apoptosis-related protein caspase-3 was significantly up-regulated and bcl-2 was observably down-regulated when NP cells were transfected with miR-15a mimics, while bax and caspase-3 were significantly down-regulated as well as bcl-2 was observably up-regulated when NP cells were transfected with miR-15a inhibitors. Further, luciferase reporter assay showed that MAP3K9, an upstream activator of MAPK kinase, was putative target of miR-15a. There was a negatively relationship between miR-15a and MAP3K9 expression in NP cells. In addition, knockdown MAP3K9 inhibited NP cells proliferation and promoted apoptosis, which further inhibited the activation of p38 and ERK MAPK pathway.

CONCLUSION

This present study revealed that miR-15a might be considered as a novel therapeutic target for IDD treatment.

Therapeutic potential of targeting microRNA-10b in established intracranial glioblastoma: first steps toward the clinic

MicroRNA-10b (miR-10b) is a unique oncogenic miRNA that is highly expressed in all GBM subtypes, while absent in normal neuroglial cells of the brain. miR-10b inhibition strongly impairs proliferation and survival of cultured glioma cells, including glioma-initiating stem-like cells (GSC). Although several miR-10b targets have been identified previously, the common mechanism conferring the miR-10b-sustained viability of GSC is unknown. Here, we demonstrate that in heterogeneous GSC, miR-10b regulates cell cycle and alternative splicing, often through the non-canonical targeting via 5'UTRs of its target genes, including MBNL1-3, SART3, and RSRC1. We have further assessed the inhibition of miR-10b in intracranial human GSC-derived xenograft and murine GL261 allograft models in athymic and immunocompetent mice. Three delivery routes for the miR-10b antisense oligonucleotide inhibitors (ASO), direct intratumoral injections, continuous osmotic delivery, and systemic intravenous injections, have been explored. In all cases, the treatment with miR-10b ASO led to targets' derepression, and attenuated growth and progression of established intracranial GBM. No significant systemic toxicity was observed upon ASO administration by local or systemic routes. Our results indicate that miR-10b is a promising candidate for the development of targeted therapies against all GBM subtypes.

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

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

Ablation of miR-10b Suppresses Oncogene-Induced Mammary Tumorigenesis and Metastasis and Reactivates Tumor-Suppressive Pathways

The invasive and metastatic properties of many human tumors have been associated with upregulation of the miRNA miR-10b, but its functional contributions in this setting have not been fully unraveled. Here, we report the generation of miR-10b-deficient mice, in which miR-10b is shown to be largely dispensable for normal development but critical to tumorigenesis. Loss of miR-10b delays oncogene-induced mammary tumorigenesis and suppresses epithelial-mesenchymal transition, intravasation, and metastasis in a mouse model of metastatic breast cancer. Among the target genes of miR-10b, the tumor suppressor genes Tbx5 and Pten and the metastasis suppressor gene Hoxd10 are significantly upregulated by miR-10b deletion. Mechanistically, miR-10b promotes breast cancer cell proliferation, migration, and invasion through inhibition of the expression of the transcription factor TBX5, leading to repression of the tumor suppressor genes DYRK1A and PTEN In clinical specimens of breast cancer, the expression of TBX5, HOXD10, and DYRK1A correlates with relapse-free survival and overall survival outcomes in patients. Our results establish miR-10b as an oncomiR that drives metastasis, termed a metastamiR, and define the set of critical tumor suppressor mechanisms it overcomes to drive breast cancer progression. Cancer Res; 76(21); 6424-35. ©2016 AACR.

Potential role of microRNA-10b down-regulation in cardiomyocyte apoptosis in aortic stenosis patients

Myocardial miR-10b down-regulation may be involved in the increase in cardiomyocyte apoptosis in AS patients, probably through apoptosis protease-activating factor-1 (Apaf-1) regulation. In turn, increased cardiomyocyte apoptosis contributes to cardiomyocyte damage and heart failure (HF) development.

miR-10b exerts oncogenic activity in human hepatocellular carcinoma cells by targeting expression of CUB and sushi multiple domains 1 (CSMD1)

BACKGROUND

Hepatocellular carcinoma (HCC) is a lethal disease, while the precise underlying molecular mechanisms of HCC pathogenesis remain to be defined. MicroRNA (miRNA), a class of non-coding small RNAs, can post-transcriptionally regulate gene expression. Altered miRNA expression has been reported in HCCs. This study assessed expression and the oncogenic activity of miRNA-10b (miR-10b) in HCC.

METHODS

Forty-five paired human HCC and adjacent non-tumor tissues were collected for qRT-PCR and immunohistochemistry analysis of miR-10b and CUB and Sushi multiple domains 1 (CSMD1), respectively. We analyzed the clinicopathological data from these patients to further determine if there was an association between miR-10b and CSMD1. HCC cell lines were used to assess the effects of miR-10b mimics or inhibitors on cell viability, migration, invasion, cell cycle distribution, and colony formation. Luciferase assay was used to assess miR-10b binding to the 3'-untranslated region (3'-UTR) of CSMD1.

RESULTS

miR-10b was highly expressed in HCC tissues compared to normal tissues. In vitro, overexpression of miR-10b enhanced HCC cell viability, migration, and invasion; whereas, downregulation of miR-10b expression suppressed these properties in HCC cells. Injection of miR-10b mimics into tumor cell xenografts also promoted xenograft growth in nude mice. Bioinformatics and luciferase reporter assay demonstrated that CSMD1 was the target gene of miR-10b. Immunocytochemical, immunohistochemical, and qRT-PCR data indicated that miR-10b decreased CSMD1 expression in HCC cells.

CONCLUSIONS

We showed that miR-10b is overexpressed in HCC tissues and miR-10b mimics promoted HCC cell viability and invasion via targeting CSMD1 expression. Our findings suggest that miR-10b acts as an oncogene by targeting the tumor suppressor gene, CSMD1, in HCC.

Up-regulation of mir-10b predicate advanced clinicopathological features and liver metastasis in colorectal cancer

Given the emerging role of microRNA in tumor disease progression, we investigated the association between miRNA 10b expression, liver metastasis, and clinicopathological of colorectal cancer (CRC). Two hundred and forty‐six pairs of samples (including CRC samples and normal adjacent tissues) from CRC patients were collected from May 2004 to May 2009. All samples verified to contain at least 80% tumor cells, and were immediately frozen in liquid nitrogen and stored at −80°C or fixed in 10% formalin for paraffin embedding. The expression of miRNA‐10b in CRC tissues was evaluated using a quantitative real‐time polymerase chain reaction RT‐PCR. Correlation between miR‐10b expression and poor clinicopathological of CRC patients were analyzed using Student's t‐tests and Chi‐square tests. A Kaplan–Meier survival curve was generated following a log‐rank test. miR‐10b expression was up‐regulated in CRC tissues (P < 0.0001) and in patients diagnosed as colorectal liver metastasis (CLM) at initial involvement or during follow‐up. When the Tumor Node Metastasis (TNM) stage was taken into consideration, the expression levels of miR‐10b were positively correlated with advanced TNM stages. In addition, the miR‐10b expression of patients diagnosed as CLM at initial involvement was significantly higher than those without liver metastasis (nCLM). Similarly, those patients developed with CLM during follow‐up (FCLM) was also markedly higher than those with nCLM. miR‐10b expression was also found correlated with advanced stage (P < 0.0001), lymph node metastasis (P = 0.025), venous infiltration (P = 0.007), poorer differentiation (P = 0.002), and served as an independent prognostic factor of poor overall survival (P < 0.0001). This study demonstrated the expression of miR‐10b had strong potential to serve as a noninvasive biomarker for CRC prognosis and predicting liver metastasis.

MicroRNA in pancreatic adenocarcinoma: predictive/prognostic biomarkers or therapeutic targets?

Pancreatic ductal adenocarcinoma (PDAC) is a tumor with a poor prognosis, short overall survival and few chemotherapeutic choices. MicroRNAs (miRNAs) are non-coding, single-stranded RNAs of around 22 nucleotides involved in the pathogenic mechanisms of carcinogenesis and metastasis. They have been studied in many tumors in order to identify potential diagnostic, prognostic or therapeutic targets. In the current literature, many studies have analyzed the role of miRNAs in PDAC. In fact, the absence of appropriate biomarkers, the difficultly of early detection of this tumor, and the lack of effective chemotherapy in patients with unresectable disease have focused attention on miRNAs as new, interesting advance in this malignancy.

In this review we analyzed the role of miRNAs in PDAC in order to understand the mechanisms of action and the difference between the onco-miRNA and the tumor suppressor miRNA. We also reviewed all the data related to the use of these molecules as predictive as well as prognostic biomarkers in the course of the disease.

Finally, the possible therapeutic use of miRNAs or anti-miRNAs in PDAC is also discussed.

In conclusion, although there is still no clinical application for these molecules in PDAC, it is our opinion that the preclinical evidence of the role of specific miRNAs in carcinogenesis, the possibility of using miRNAs as diagnostic or prognostic biomarkers, and their potential therapeutic role, warrant future studies in PDAC.

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 miRacle in Pancreatic Cancer by miRNAs: Tiny Angels or Devils in Disease Progression

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with increasing incidence and high mortality. Surgical resection is the only potentially curative treatment of patients with PDAC. Because of the late presentation of the disease, about 20 percent of patients are candidates for this treatment. The average survival of resected patients is between 12 and 20 months, with a high probability of relapse. Standard chemo and radiation therapies do not offer significant improvement of the survival of these patients. Furthermore, novel treatment options aimed at targeting oncogenes or growth factors in pancreatic cancer have proved unsuccessful. Thereby, identifying new biomarkers that can detect early stages of this disease is of critical importance. Among these biomarkers, microRNAs (miRNAs) have supplied a profitable recourse and become an attractive focus of research in PDAC. MiRNAs regulate many genes involved in the development of PDAC through mRNA degradation or translation inhibition. The possibility of intervention in the molecular mechanisms of miRNAs regulation could begin a new generation of PDAC therapies. This review summarizes the reports describing miRNAs involvement in cellular processes involving pancreatic carcinogenesis and their utility in diagnosis, survival and therapeutic potential in pancreatic cancer.

microRNA-10b is a prognostic biomarker for melanoma

Malignant melanoma is an aggressive form of skin cancer. Recently, drug therapy of advanced disease has been revolutionized by new agents. More therapeutic options, coupled with the desire to extend treatment to the adjuvant setting mean that prognostic biomarkers that can be assayed from formalin-fixed paraffin-embedded clinical would be valuable. microRNAs have potential to fill this need. We analyzed 377 microRNAs in 79 primary melanomas and 32 metastases using a split sample discovery strategy. From a discovery analysis using 40 thick primary melanomas (20 cases with metastasis and 20 controls without metastasis at 5 years), microRNA expression was measured by quantitative RT-PCR (QRT-PCR). MiR-10b emerged as a candidate prognostic microRNA. This was confirmed in an independent validation set of thick primary melanomas (20 cases with metastasis and 19 controls without metastasis at 5 years). In the combined discovery and validation cohorts (n=79), miR-10b expression showed a 3.7-fold increase in expression between cases and controls (P=0.005) and showed a trend of increasing expression between primary melanomas and their matched metastases (P<0.001). In situ hybridization showed expression was in melanoma cells and correlated with expression measured by QRT-PCR (P=0.0005). We used the combined discovery and validation samples to verify the prognostic value of additional candidate microRNAs identified from other studies, and proceeded to analyze miR-200b. We demonstrated that miR-10b and miR-200b showed independent prognostic value (P=0.002 and 0.047, respectively) in multivariable analysis alongside known clinico-pathological prognostic features (eg, Breslow thickness) using a Cox proportional hazards regression model. Furthermore, the addition of these microRNAs to the clinico-pathological features led to an improved regression model with better identification of aggressive thick melanomas. Taken together, these data suggest that miR-10b is a new prognostic microRNA for melanoma and that there could be a place for microRNA analysis in stratifying melanoma for therapy.

MicroRNA-10b inhibition reduces E2F1-mediated transcription and miR-15/16 activity in glioblastoma

MicroRNA-10b (miR-10b) is commonly elevated in glioblastoma (GBM), while not expressed in normal brain tissues. Targeted inhibition of miR-10b has pleiotropic effects on GBM derived cell lines, it reduces GBM growth in animal models, but does not affect normal neurons and astrocytes. This data raises the possibility of developing miR-10b-targeting GBM therapy. However, the mechanisms contributing to miR-10b-mediated glioma cell survival and proliferation are unexplored. We found that inhibition of miR-10b has distinct effects on specific glioma cell lines. In cells expressing high levels of tumor suppressor p21WAF1/Cip1, it represses E2F1-mediated transcription, leading to down-regulation of multiple E2F1 target genes encoding for S-phase specific proteins, epigenetic modulators, and miRNAs (e.g. miR-15/16), and thereby stalling progression through the S-phase of cell cycle. Subsequently, miR-15/16 activities are reduced and many of their direct targets are de-repressed, including ubiquitin ligase FBXW7 that destabilizes Cyclin E. Conversely, GBM cells expressing low p21 level, or after p21 knock-down, exhibit weaker or no E2F1 response to miR-10b inhibition. Comparative analysis of The Cancer Genome Atlas revealed a strong correlation between miR-10b and multiple E2F target genes in GBM and low-grade glioma. Taken together, these findings indicate that miR-10b regulates E2F1-mediated transcription in GBM, in a p21-dependent fashion.

Heterogeneity of miR-10b expression in circulating tumor cells

Circulating tumor cells (CTCs) in the blood of cancer patients are recognized as important potential targets for future anticancer therapies. As mediators of metastatic spread, CTCs are also promising to be used as ‘liquid biopsy’ to aid clinical decision-making. Recent work has revealed potentially important genotypic and phenotypic heterogeneity within CTC populations, even within the same patient. MicroRNAs (miRNAs) are key regulators of gene expression and have emerged as potentially important diagnostic markers and targets for anti-cancer therapy. Here, we describe a robust in situ hybridization (ISH) protocol, incorporating the CellSearch^® CTC detection system, enabling clinical investigation of important miRNAs, such as miR-10b on a cell by cell basis. We also use this method to demonstrate heterogeneity of such as miR-10b on a cell-by-cell basis. We also use this method to demonstrate heterogeneity of miR-10b in individual CTCs from breast, prostate and colorectal cancer patients.

Contribution of microRNA analysis to characterisation of pancreatic lesions: a review

Pancreatic tumours are usually very aggressive cancer with a poor prognosis. A limitation of pancreatic imaging techniques is that lesions are often of ambiguous relevance. The inability to achieve a definitive diagnosis based on cytological evaluation of specimens, due to sampling error, paucicellular samples or coexisting inflammation, might lead to delay in clinical management. Given the morbidity associated with pancreatectomy, a proper selection of patients for surgery is fundamental. Many studies have been conducted in order to identify specific markers that could support the early diagnosis of pancreatic lesions, but, to date, none of them allow to diagnose pancreatic cancer with high sensitivity and specificity. MicroRNAs (miRNA) are small non-coding RNAs (19-25 nucleotides) that regulate gene expression interacting with mRNA targets. It is now established that each tissue shows a characteristic miRNA expression pattern that could be modified in association with a number of different diseases including neoplasia. Due to their key role in the regulation of gene expression, in the last years several studies have investigated miRNA tissue-specific expression, quantification and functional analysis to understand their peculiar involvement in cellular processes. The aim of this review is to focus on miRNA expression in pancreatic cancer and their putative role in early characterisation of pancreatic lesions.

Predictive Value of Serum miR-10b, miR-29c, and miR-205 as Promising Biomarkers in Esophageal Squamous Cell Carcinoma Screening

Esophageal squamous cell carcinoma (ESCC) is a leading cause of cancer-related deaths worldwide. The high mortality of ESCC is mainly due to late diagnosis. Current detection methods have their own weakness, including high costs and invasive procedures. MicroRNA assays are shown to have great potential to be accurate and noninvasive methods for ESCC screening. In this study, we selected 3 microRNAs, miR-10b, miR-29c, and miR-205, to assess their diagnostic value in ESCC screening. Fifty ESCC patients and 50 healthy controls are recruited in our study. Blood samples are collected from the total 100 participants. MicroRNAs were extracted from serum and quantified by qRT-PCR, which their relative expressions were normalized by internal control, U6 snRNA. Statistical analyses were conducted to compare microRNAs level as well as other clinical characteristics between 2 groups. The levels of serum miR-29c and miR-205 were significantly downregulated in ESCC patients compared with healthy volunteers. In contrast, ESCC patients appeared to have a higher level of miR-10b than healthy controls. ROC curve analyses revealed that the AUC value for miR-10b, miR-29c, and miR-205 were 0.85 (95% CI: 0.79-0.93; sensitivity = 76%; specificity = 84%), 0.72 (95% CI: 0.62-0.82; sensitivity = 68%; specificity = 68%), and 0.72 (95% CI: 0.62-0.83; sensitivity = 70%; specificity = 64%), respectively, suggesting that miR-10b, miR-29c, and miR-205 have great potential to be noninvasive screening tools for ESCC detection.

Small nucleolar RNA U91 is a new internal control for accurate microRNAs quantification in pancreatic cancer

BACKGROUND

RT-qPCR quantification of miRNAs expression may play an essential role in pancreatic ductal adenocarcinoma (PDAC) diagnostics. RT-qPCR-based experiments require endogenous controls for the result normalization and reliability. However, expression instability of reference genes in tumors may introduce bias when determining miRNA levels.

METHODS

We investigated expression of 6 miRNAs, isolated from FFPE samples of pancreatic adenocarcinomas. Four internal controls were utilized for RT-qPCR result normalization: artificial miR-39 from C. elegans, U6 snRNA, miR-16 and snoRNA U91.

RESULTS

We found miR-21, miR-155 or miR-217 expression values in tumors may differ up to several times, depending on selected internal controls. Moreover, different internal controls can produce controversial results for miR-96, miR-148a or miR-196a quantification. Also, expression of our endogenous controls varied significantly in tumors. U6 demonstrated variation from -1.03 to 8.12-fold, miR-16 from -2.94 up to 7.38-fold and the U91 from -3.05 to 4.36-fold respectively. On the other hand, the most stable gene, determined by NormFinder algorithm, was U91. Each miRNA normalized relatively to the spike or U91, demonstrated similar expression values. Thus, statistically significant and insignificant differences between tumors and normal tissues for miRNAs were equal for the spike and the U91. Also, the differences between the spike and U91 were statistically insignificant for all of miRs except miR-217. Among three endogenous controls, U91 had the lowest average expression values and standard deviation in cancer tissues.

CONCLUSIONS

We recommend U91 as a new normalizer for miRNA quantification in PDACs.

MicroRNA-10b promotes migration and invasion through Hoxd10 in human gastric cancer

BACKGROUND

This study aims to investigate the effect of miR-10b overexpression on cancer cell proliferation, migration, invasion, and Hoxd10 expression.

METHODS

The effect of miR-10b on proliferation, migration, and invasion of MKN-28, BGC-823, and SGC-7901 cells and the expression of Hoxd10 protein in SGC-7901 and BGC-823 cells were detected following transfection of miR-10b inhibitor or Negative Control B. Expression of Hoxd10 protein in 436 paraffin-embedded cancer tissues was also investigated.

RESULTS

miR-10b was significantly upregulated in AGS, MKN-28, BGC-823, HCG-27, SGC-7901, and MKN-45 cell lines, miR-10b inhibitor significantly inhibited proliferation and migration of MKN-45, BGC-823 and SGC-7901 cells 48 h after transfection, while Hoxd10 protein in these cells lines had increased 72 h after transfection. Hoxd10 was highly expressed in gastric cancer and correlated with size of tumor, Lauren classification, depth of invasion, lymph node and distant metastasis, Tumor-Node-Metastasis (TNM) stage, and prognosis.

CONCLUSIONS

miR-10b promotes migration and invasion through Hoxd10 in human gastric cancer cell lines and may play an important role in tumorigenesis, progression, and prognosis.

Targeting miRNAs for pancreatic cancer therapy

Pancreatic cancer (PC) is the fourth leading cause of cancer-related deaths in the United States and has a median 5-year survival rate less than 5%. Although surgery offers the best chance for a cure for pancreatic cancer, less than 20% of patients are eligible for potentially curative resection, because in most cases, the cancer has already spread locally or to distant organs at diagnosis, precluding resection. MicroRNAs (miRNAs) are small noncoding, endogenous, single-stranded RNAs that are pivotal regulators of posttranscriptional gene expression. Extensive studies of miRNAs over the past several years have revealed that the expression of miRNAs is frequently deregulated in pancreatic cancer patients and that this deregulation contributes to the pathogenesis and aggressiveness of the disease. Currently, investigators are studying the use of miRNAs as diagnostic and/or prognostic biomarkers and therapeutic tools for pancreatic cancer. Rapid discovery of many miRNA targets and their relevant pathways has contributed to the development of miRNA-based therapeutics. In particular, the transcription factor Forkhead box M1 (FOXM1) is overexpressed in the majority of cancer patients, including those with pancreatic cancer. This overexpression is implicated to have a role in tumorigenesis, progression, and metastasis. This important role of FOXM1 affirms its usefulness in therapeutic interventions for pancreatic cancer. In this review, we summarize the current knowledge and concepts concerning the involvement of miRNAs and FOXM1 in pancreatic cancer development and describe the roles of the miRNA-FOXM1 signaling pathway in pancreatic cancer initiation and progression. Additionally, we describe some of the technical challenges in the use of the miRNA-FOXM1 signaling pathway in pancreatic cancer treatment.

microRNAs with prognostic significance in pancreatic ductal adenocarcinoma: A meta-analysis

BACKGROUND

Reports have described the prognostic relevance of microRNAs (miRNAs) in patients treated for pancreatic ductal adenocarcinoma (PDAC). However, many of these include small numbers of patients. To increase statistical power and improve translation, we performed a systematic review and meta-analysis to determine a pooled conclusion. We examined the impact of miRNAs on overall survival (OS) and disease-free survival (DFS) in PDAC.

METHODS

Eligible studies were identified and quality assessed using multiple search strategies (last search December 2014). Data were collected from studies correlating clinical outcomes with dysregulated tumoural or blood miRNAs. Studies were pooled, and combined hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate strength of the associations.

RESULTS

Twenty studies involving 1525 patients treated for PDAC were included. After correcting for publication bias, OS was significantly shortened in patients with high tumoural miR-21 (adjusted HR = 2.48; 1.96-3.14). This result persisted when only studies adjusting for adjuvant chemotherapy were combined (adjusted HR = 2.72; 1.91-3.89). High miR-21 also predicted reduced DFS (adjusted HR = 3.08; 1.78-5.33). Similarly, we found significant adjusted HRs for poor OS for high miR-155, high miR-203, and low miR-34a; and unadjusted HRs for high miR-222 and high miR-10b. The small number of studies, limited number of miRNAs and paucity of multivariate analyses are the limitations of our study.

CONCLUSIONS

This is the first rigorous pooled analysis assessing miRNAs as prognostic biomarkers in PDAC. Tumoural miR-21 overexpression emerged as an important predictor of poor prognosis after PDAC resection independent of other clinicopathologic factors, including adjuvant chemotherapy use.

MicroRNAs in Pancreatic Cancer: Involvement in Carcinogenesis and Potential Use for Diagnosis and Prognosis

Pancreatic cancer is one of the most fatal malignancies with increasing incidence and high mortality. Possibilities for early diagnosis are limited and there is currently no efficient therapy. Molecular markers that have been introduced into diagnosis and treatment of other solid tumors remain unreciprocated in this disease. Recent discoveries have shown that certain microRNAs (miRNAs) take part in fundamental molecular processes associated with pancreatic cancer initiation and progression including cell cycle, DNA repair, apoptosis, invasivity, and metastasis. The mechanism involves both positive and negative regulation of expression of protooncogenes and tumor suppressor genes. Various miRNAs are expressed at different levels among normal pancreatic tissue, chronic pancreatitis, and pancreatic cancer and may therefore serve as a tool to differentiate chronic pancreatitis from early stages of cancer. Other miRNAs can indicate the probable course of the disease or determine the survival prognosis. In addition, there is a growing interest directed at the understanding of miRNA-induced molecular mechanisms. The possibility of intervention in the molecular mechanisms of miRNAs regulation could begin a new generation of pancreatic cancer therapies. This review summarizes the recent reports describing functions of miRNAs in cellular processes underlying pancreatic cancerogenesis and their utility in diagnosis, survival prognosis, and therapy.

MicroRNA in intervertebral disc degeneration

Aetiology of intervertebral disc degeneration (IDD) is complex, with genetic, developmental, biochemical and biomechanical factors contributing to the disease process. It is becoming obvious that epigenetic processes influence evolution of IDD as strongly as the genetic background. Deregulated phenotypes of nucleus pulposus cells, including differentiation, migration, proliferation and apoptosis, are involved in all stages of progression of human IDD. Non-coding RNAs, including microRNAs, have recently been recognized as important regulators of gene expression. Research into roles of microRNAs in IDD has been very active over the past 5 years. Our review summarizes current research enlightenment towards understanding roles of microRNAs in regulating nucleus pulposus cell functions in IDD. These exciting findings support the notion that specific modulation of microRNAs may represent an attractive approach for management of IDD.

Circulating microRNAs as biomarkers in hepatocellular carcinoma screening: a validation set from China

Hepatocellular carcinoma (HCC) is a global public health concern. Current diagnostic methods show poor performance in early-stage HCC detection. Accumulating evidences revealed the great potential of microRNAs (miRNAs) as noninvasive biomarkers in HCC detection. In this study, we examined the diagnostic performance of serum miR-10b, miR-106b, and miR-181a for HCC screening in China. Furthermore, a systematic review of previous related studies was conducted to confirm our results. One hundred eight participants including 27 HCC patients, 31 chronic liver disease (CLD) patients, and 50 healthy people were recruited in this study. Blood specimen was drawn from each participant to extract serum miRNAs. Statistical analyses were performed to assess the 3 miRNAs levels in HCC, CLD patients, and normal controls. A meta-analysis was conducted to further assess the diagnostic value of miRNAs in HCC detection based on previous studies. All these miRNAs (miR-10b, miR-181a, miR-106b) could well discriminate HCC patients from normal controls, with area under the receiver-operating characteristic curve (AUC) values of 0.85 (95% confidence interval [CI]: 0.76-0.94), 0.82 (95% CI: 0.72-0.91), and 0.89 (95% CI: 0.81-0.97), respectively. In addition, these miRNAs could distinguish HCC cases from CLD controls with a medium accuracy. However, the ability of these miRNAs in differentiating CLD patients from normal controls was not satisfactory. Panel of these miRNAs displayed a better performance compared with single miRNA assay, with AUC values of 0.94 (95% CI: 0.89-0.99) in discriminating HCC patients from normal controls and 0.91 (95% CI: 0.80-0.97) in discriminating HCC patients from CLD controls. Results of meta-analysis of previous studies combined with the current study suggested that circulating miRNAs could well differentiate HCC from normal controls, with AUC values of 0.86 (95% CI: 0.82-0.89) for single miRNA assay and 0.94 (95% CI: 0.91-0.96) for miRNA panel assay. Serum miR-10b, miR-106b, and miR-181a have great potential to serve as accurate and noninvasive biomarkers for HCC preliminary screening. Meta-analysis of previous studies combined with current study further confirmed that circulating miRNAs could play an important role in HCC detection. Further large-scale studies are needed to confirm the clinical significance of circulating miRNAs in HCC screening.

MicroRNA-10b Triggers the Epithelial-Mesenchymal Transition (EMT) of Laryngeal Carcinoma Hep-2 Cells by Directly Targeting the E-cadherin

Laryngeal carcinoma is the second most common malignancy of the head and neck squamous cell carcinoma. Therefore, there is an urgent need to understand the molecular mechanism of its metastasis. The present study was designed to investigate effects of miR-10b on the invasion and migration of laryngeal Hep-2 cells. We found that miR-10b had limited effects on cell proliferation; however, it can significantly promote the migration and invasion of Hep-2 cells. Further studies revealed that overexpression of miR-10b can induce the epithelial-mesenchymal transition (EMT) of Hep-2 cells by acquiring mesenchymal spindle-like morphology and increasing the expression of N-cadherin (N-Cad) with a concomitant decrease of E-cadherin (E-Cad). However, the messenger RNA (mRNA) and protein level of transcription factors such as Snail, Slug, Twist and ZEB was not changed during this process. Bioinformatic analysis revealed that miR-10b can directly target CDH1 (E-Cad gene) at nucleotides 461 and 481 within the 3'-UTR. This was confirmed by the results that miR-10 downregulated the protein and mRNA levels of E-Cad via a time-dependent manner and luciferase analysis by use of four-nucleotide substitution in the core binding sites. The present study provided a better understanding of laryngeal carcinoma metastasis and the roles of miR-10b during this process.

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.

miRNAs in pancreatic cancer: therapeutic potential, delivery challenges and strategies

Pancreatic ductal adenocarcinoma (PDAC) is a severe pancreatic malignancy and is predicted to victimize 1.5% of men and women during their lifetime (Cancer statistics: SEER stat fact sheet, National Cancer Institute, 2014). miRNAs have emerged as a promising prognostic, diagnostic and therapeutic tool to fight against pancreatic cancer. miRNAs could modulate gene expression by imperfect base-pairing with target mRNA and hence provide means to fine-tune multiple genes simultaneously and alter various signaling pathways associated with the disease. This exceptional miRNA feature has provided a paradigm shift from the conventional one drug one target concept to one drug multiple target theory. However, in vivo miRNA delivery is not fully realized due to challenges posed by this special class of therapeutic molecules, which involves thorough understanding of the biogenesis and physicochemical properties of miRNA and delivery carriers along with the pathophysiology of the PDAC. This review highlights the delivery strategies of miRNA modulators (mimic/inhibitor) in cancer with special emphasis on PDAC since successful delivery of miRNA in vivo constitutes the major challenge in clinical translation of this promising class of therapeutics.

Insights into the Role of microRNAs in Pancreatic Cancer Pathogenesis: Potential for Diagnosis, Prognosis, and Therapy

Pancreatic cancer is a highly lethal malignancy and a fourth leading cause of cancer-related death in the United States. Poor survival of pancreatic cancer patients is largely because of its asymptomatic progression to advanced stage against which no effective therapy is currently available. Over the years, we have developed significant knowledge of molecular progression of pancreatic cancer and identified several genetic and epigenetic aberrations to be involved in its etiology and aggressive behavior. In that regard, recent lines of evidence have suggested important roles of microRNAs (miRNAs/miRs) in pancreatic cancer pathogenesis. microRNAs belonging to a family of small, noncoding RNAs are able to control diverse biological processes due to their ability to regulate gene expression at the posttranscriptional level. Accordingly, dysregulation of miRNAs can lead to several disease conditions, including cancer. There is a long list of microRNAs that exhibit aberrant expression in pancreatic cancer and serve as key microplayers in its initiation, progression, metastasis, and chemoresistance. These findings have suggested that microRNAs could be exploited as novel biomarkers for diagnostic and prognostic assessments of pancreatic cancer and as targets for therapy. This book chapter describes clinical problems associated with pancreatic cancer, roles that microRNAs play in various aspects of pancreatic cancer pathogenesis, and envision opportunities for potential use of microRNAs in pancreatic cancer management.

DNA methylation downregulated mir-10b acts as a tumor suppressor in gastric cancer

BACKGROUND

MicroRNAs act as tumor suppressors or oncogenes. The pathological roles of miRNAs in gastric tumorigenesis are largely unknown. Although miR-10b was identified as an miRNA deregulator expressed in gastric cancer (GC), there also exists some debate on whether miR-10b is acting as tumor suppressor or oncogene in GC.

METHODS

Quantitative RT-PCR was employed to investigate the level of miR-10b in GC tissues and matched adjacent normal tissues (n = 100). In vitro cell proliferation, apoptosis assays, cell migration, and invasion assays were performed to elucidate the biological effects of miR-10b. Because silencing of miRNA by promoter CpG island methylation may be an important mechanism in tumorigenesis, GC cells were treated with 5-aza-2'-deoxycytidine and trichostatin A, and expression changes of miR-10b were subsequently examined by quantitative RT-PCR. Furthermore, the methylation status of the CpG island upstream of miR-10b was analyzed by methylation-specific PCR in GC tissues (n = 29).

RESULTS

We showed here that miR-10b was significantly downregulated in GC cell lines and tissues as demonstrated by quantitative real-time PCR. Overexpression of miR-10b in MGC-803 and HGC-27 dramatically suppressed cell proliferation, migration, invasion, and induced apoptosis. Moreover, we demonstrated that T-cell lymphoma invasion and metastasis (Tiam1) was a target of miR-10b. Furthermore, 5-aza-2'-deoxycytidine and trichostain A increased miR-10b expression, and the methylation level was high in the CpG islands upstream of miR-10b gene.

CONCLUSIONS

Taken together, these findings suggest that miR-10b may function as a novel tumor suppressor and is partially silenced by DNA hypermethylation in GC.

MicroRNA expression profiling of diagnostic needle aspirates from surgical pancreatic cancer specimens

Purpose

MicroRNAs (miRNAs) have been widely investigated as potential biomarkers for several malignancies. To establish the feasibility of miRNA expression profiling of small biopsy samples of pancreatic cancers, we assessed expression profiles in freshly collected aspirates obtained immediately after surgical resection of the pancreas.

Methods

We used separate fine needles (20-23 gauge) to aspirate the pancreatic cancer and adjacent normal pancreatic tissue. miRNAs that were differentially expressed in pancreatic cancers and matched paraneoplastic normal pancreatic tissues were identified using an miRNA microarray.

Results

We identified 158 aberrantly expressed miRNAs in pancreatic cancers; 51 were overexpressed and 107 underexpressed compared with normal pancreatic tissue. To confirm the microarray findings, quantitative RT-PCR was performed on individual samples. We chose eight miRNAs for further analysis; of which five were overexpressed (miR-21, miR-27a, miR-146a, miR-200a, and miR-196a) and three underexpressed (miR-217, miR-20a, and miR-96) in pancreatic cancer samples compared to benign pancreatic tissue. Expression of miR-21, miR-27a, miR-146a, miR-200a, and miR-196a was significantly increased in cancer fine-needle aspirates relative to matched controls in all samples. Expression of miR-217, miR-20a, and miR-96 was significantly downregulated in almost all pancreatic cancer tissues.

Conclusion

We demonstrate the feasibility of performing miRNA profiling on very small specimens obtained using fine-needle aspiration of pancreatic cancers.

Regulation of BGC-823 cell sensitivity to adriamycin via miRNA-135a-5p

MicroRNAs (miRNAs) play an important role in the genesis and development of gastric cancer. In the present study, we determined whether miRNA-135a-5p expression was increased in gastric cancer compared with adjacent non-tumor tissues using 20 pairs of gastric cancer and para-carcinoma tissue samples which were assessed via microarray and bioinformatics analysis, and western blotting. The protein content detection showed that miRNA‑135a-5p expression was inversely correlated with AP-2α. Bioinformatics analysis revealed that AP-2α contains a putative miRNA-135a-5p target, which was confirmed as a direct target using the 3'-UTR luciferase reporter system. Additionally, an increase and decrease of miRNA-135a-5p inhi-bited or impaired adriamycin-induced apoptosis in BGC-823 cells (p<0.05, compared with the group without gene intervention), respectively. Luciferase reporter experiments confirmed that AP-2α bound to the BCL-2 promoter and affected its transcription. Therefore, miRNA-135a-5p increased BCL-2 via AP-2α and consequently enhanced cell resistance to apoptosis. This newly identified miRNA-135a-5p-AP-2α-BCL-2 pathway provides insight for the treatment of gastric cancer and solution for insensitivity of gastric cancer to chemotherapy drugs.

N-methylnicotinamide and nicotinamide N-methyltransferase are associated with microRNA-1291-altered pancreatic carcinoma cell metabolome and suppressed tumorigenesis

The cell metabolome comprises abundant information that may be predictive of cell functions in response to epigenetic or genetic changes at different stages of cell proliferation and metastasis. An unbiased ultra-performance liquid chromatography-mass spectrometry-based metabolomics study revealed a significantly altered metabolome for human pancreatic carcinoma PANC-1 cells with gain-of-function non-coding microRNA-1291 (miR-1291), which led to a lower migration and invasion capacity as well as suppressed tumorigenesis in a xenograft tumor mouse model. A number of metabolites, including N-methylnicotinamide, involved in nicotinamide metabolism, and l-carnitine, isobutyryl-carnitine and isovaleryl-carnitine, involved in fatty acid metabolism, were elevated in miR-1291-expressing PANC-1. Notably, N-methylnicotinamide was elevated to the greatest extent, and this was associated with a sharp increase in nicotinamide N-methyltransferase (NNMT) mRNA level in miR-1291-expressing PANC-1 cells. In addition, expression of NNMT mRNA was inversely correlated with pancreatic tumor size in the xenograft mouse model. These results indicate that miR-1291-altered PANC-1 cell function is associated with the increase in N-methylnicotinamide level and NNMT expression, and in turn NNMT may be indicative of the extent of pancreatic carcinogenesis.

High-frequency aberrantly methylated targets in pancreatic adenocarcinoma identified via global DNA methylation analysis using methylCap-seq

BACKGROUND

Extensive reprogramming and dysregulation of DNA methylation is an important characteristic of pancreatic cancer (PC). Our study aimed to characterize the genomic methylation patterns in various genomic contexts of PC. The methyl capture sequencing (methylCap-seq) method was used to map differently methylated regions (DMRs) in pooled samples from ten PC tissues and ten adjacent non-tumor (PN) tissues. A selection of DMRs was validated in an independent set of PC and PN samples using methylation-specific PCR (MSP), bisulfite sequencing PCR (BSP), and methylation sensitive restriction enzyme-based qPCR (MSRE-qPCR). The mRNA and expressed sequence tag (EST) expression of the corresponding genes was investigated using RT-qPCR.

RESULTS

A total of 1,131 PC-specific and 727 PN-specific hypermethylated DMRs were identified in association with CpG islands (CGIs), including gene-associated CGIs and orphan CGIs; 2,955 PC-specific and 2,386 PN-specific hypermethylated DMRs were associated with gene promoters, including promoters containing or lacking CGIs. Moreover, 1,744 PC-specific and 1,488 PN-specific hypermethylated DMRs were found to be associated with CGIs or CGI shores. These results suggested that aberrant hypermethylation in PC typically occurs in regions surrounding the transcription start site (TSS). The BSP, MSP, MSRE-qPCR, and RT-qPCR data indicated that the aberrant DNA methylation in PC tissue and in PC cell lines was associated with gene (or corresponding EST) expression.

CONCLUSIONS

Our study characterized the genome-wide DNA methylation patterns in PC and identified DMRs that were distributed among various genomic contexts that might influence the expression of corresponding genes or transcripts to promote PC. These DMRs might serve as diagnostic biomarkers or therapeutic targets for PC.

Altered interphase fluorescence in situ hybridization profiles of chromosomes 4, 8q24, and 9q34 in pancreatic ductal adenocarcinoma are associated with a poorer patient outcome

Most patients with pancreatic ductal adenocarcinoma (PDAC) die within 6 months of diagnosis. However, 20% to 25% patients undergoing total tumor resection remain alive and disease-free 5 years after diagnostic surgery. Few studies on tumor markers have predicted patient prognosis and/or survival. We evaluated the effect of tumor cytogenetic copy number changes detected by interphase fluorescence in situ hybridization on overall survival (OS) of 55 PDAC patients. The prognostic value of copy number changes showing an effect on OS was validated in an external cohort of 44 surgically resected PDAC patients by comparative genomic hybridization arrays, and the genes coded in altered chromosomes with prognostic value were identified by high-density single-nucleotide polymorphism arrays in 20 cases. Copy number changes of chromosomes 4 and 9q34 with gains of 8q24 were independently associated with shorter OS. On the basis of these three chromosomal alterations, a score is proposed that identifies patients with significantly different (P < 0.001) 5-year OS rates: 60% ± 20%, 16% ± 8%, and 0% ± 0%, respectively. Our results show an association between tumor cytogenetics and OS of PDAC patients and provide the basis for further prognostic stratification of patients undergoing complete tumor resection. Further studies to identify specific genes coded in these chromosomes and their functional consequences are necessary to understand the clinical effect of these changes.

3'LIFE: a functional assay to detect miRNA targets in high-throughput

MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene output at the post-transcriptional level by targeting degenerate elements primarily in 3'untranslated regions (3'UTRs) of mRNAs. Individual miRNAs can regulate networks of hundreds of genes, yet for the majority of miRNAs few, if any, targets are known. Misexpression of miRNAs is also a major contributor to cancer progression, thus there is a critical need to validate miRNA targets in high-throughput to understand miRNAs' contribution to tumorigenesis. Here we introduce a novel high-throughput assay to detect miRNA targets in 3'UTRs, called Luminescent Identification of Functional Elements in 3'UTRs (3'LIFE). We demonstrate the feasibility of 3'LIFE using a data set of 275 human 3'UTRs and two cancer-relevant miRNAs, let-7c and miR-10b, and compare our results to alternative methods to detect miRNA targets throughout the genome. We identify a large number of novel gene targets for these miRNAs, with only 32% of hits being bioinformatically predicted and 27% directed by non-canonical interactions. Functional analysis of target genes reveals consistent roles for each miRNA as either a tumor suppressor (let-7c) or oncogenic miRNA (miR-10b), and preferentially target multiple genes within regulatory networks, suggesting 3'LIFE is a rapid and sensitive method to detect miRNA targets in high-throughput.

MicroRNA modulation combined with sunitinib as a novel therapeutic strategy for pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and mortal cancer, characterized by a set of known mutations, invasive features, and aberrant microRNA expression that have been associated with hallmark malignant properties of PDAC. The lack of effective PDAC treatment options prompted us to investigate whether microRNAs would constitute promising therapeutic targets toward the generation of a gene therapy approach with clinical significance for this disease. In this work, we show that the developed human serum albumin–1-palmitoyl-2-oleoyl-sn-glycero-3-ethylphosphocholine:cholesterol/anti-microRNA oligonucleotides (+/−) (4/1) nanosystem exhibits the ability to efficiently deliver anti-microRNA oligonucleotides targeting the overexpressed microRNAs miR-21, miR-221, miR-222, and miR-10 in PDCA cells, promoting an almost complete abolishment of microRNA expression. Silencing of these microRNAs resulted in a significant increase in the levels of their targets. Moreover, the combination of microRNA silencing, namely miR-21, with low amounts of the chemotherapeutic drug sunitinib resulted in a strong and synergistic antitumor effect, showing that this combined strategy could be of great importance for therapeutic application in PDAC.

MicroRNA-135a inhibits cell proliferation by targeting Bmi1 in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal solid tumor due to the lack of reliable early detection markers and effective therapies. MicroRNAs (miRNAs), noncoding RNAs that regulate gene expression, are involved in tumorigenesis and have a remarkable potential for the diagnosis and treatment of malignancy. In this study, we investigated aberrantly expressed miRNAs involved in PDAC by comparing miRNA expression profiles in PDAC cell lines with a normal pancreas cell line and found that miR-135a was significantly down-regulated in the PDAC cell lines. The microarray results were validated by qRT-PCR in PDAC tissues, paired adjacent normal pancreatic tissues, PDAC cell lines, and a normal pancreas cell line. We then defined the tumor-suppressing significance and function of miR-135a by constructing a lentiviral vector to express miR-135a. The overexpression of miR-135a in PDAC cells decreased cell proliferation and clonogenicity and also induced G1 arrest and apoptosis. We predicted Bmi1 may be a target of miR-135a using bioinformatics tools and found that Bmi1 expression was markedly up-regulated in PDAC. Its expression was inversely correlated with miR-135a expression in PDAC. Furthermore, a luciferase activity assay revealed that miR-135a could directly target the 3'-untranslated region (3'-UTR) of Bmi1. Taken together, these results demonstrate that miR-135a targets Bmi1 in PDAC and functions as a tumor suppressor. miR-135a may offer a new perspective for the development of effective miRNA-based therapy for PDAC.

Elevated expression level of microRNA-196a is predictive of intestinal-type intraductal papillary mucinous neoplasm of the pancreas

OBJECTIVES

Aberrant expression of several microRNAs (miRs) has been reported in various neoplasms including intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. MicroRNA-196a (miR-196a) is up-regulated in Barrett esophagus (characterized by intestinal metaplasia) and in colorectal cancer; this relationship between intestinal characteristics and miR-196a might also be applicable to intestinal-type IPMNs. The aim of this study was to evaluate whether intestinal-type IPMNs can be discriminated from non-intestinal-type IPMNs by the expression level of miR-196a in tissue and pancreatic juice samples.

METHODS

Thirty-seven formalin-fixed paraffin-embedded tissue samples (including 3 of normal pancreatic ducts) and 36 pancreatic juice samples were obtained. The expression level of miR-196a measured by quantitative reverse transcription-polymerase chain reaction assays was compared between intestinal-type and non-intestinal-type IPMNs.

RESULTS

MicroRNA-196a expression in intestinal-type IPMN tissue samples (n = 18) was significantly higher than that of non-intestinal-type IPMNs (n = 16) (P < 0.001). Similarly, miR-196a expression in pancreatic juice samples of intestinal-type IPMNs (n = 6) was significantly higher than that of non-intestinal-type IPMNs (n = 30) (P = 0.008), and the sensitivity and specificity for prediction of intestinal-type IPMNs using pancreatic juice samples were both 83%.

CONCLUSIONS

Elevated expression of miR-196a in pancreatic juice samples is predictive of intestinal-type IPMNs.

MicroRNA-10b promotes migration and invasion through KLF4 and HOXD10 in human bladder cancer

The present study was performed to investigate the effect of microRNA-10b (miR-10b) on cell migration and invasion in human bladder cancer (BC). Real-time PCR was performed to detect the expression of miR-10b in BC cell lines. miR-10b mimics, the negative control for mimics, miR-10b inhibitor and the negative control for inhibitor were transfected into BC cell lines and the effects of miR-10b on the migration and invasion of cells were investigated through Transwell assay. Meanwhile, protein levels of KLF4, HOXD10, E-cadherin and MMP14 were measured. Luciferase assays were also performed to validate KLF4 and HOXD10 as miR-10b targets. In vivo metastasis assay was performed to validate if miR-10b can promote BC cell line metastasis in vivo. miR-10b is significantly upregulated in BC cell lines and metastatic tissues. Increased miR-10b expression significantly enhanced BC cell migration and invasion, while decreased miR-10b expression reduced cell migration and invasion. In vivo metastasis assay demonstrated that overexpression of miR-10b markedly promoted BC metastasis. Moreover, KLF4 and HOXD10 were identified as direct targets of miR-10b in BC cells. Silencing of KLF4 or HOXD10 recapitulated the pro-metastatic function. Furthermore, we found that E-cadherin and MMP14 may be the downstream factors of KLF4 and HOXD10 in the suppression of BC metastasis by miR-10b. These data suggest that miR-10b may function as oncogenes in BC cells. Targeting these novel strategies, inhibition of miR-10b/KLF4/E-cadherin axis and miR-10b/HOXD10/MMP14 axis may be helpful as a therapeutic approach to block BC cell metastasis.

MicroRNAs in pancreatic malignancy: progress and promises

Despite progress in recent years, pancreatic cancer still remains a major clinical challenge. Its incidence and mortality rates have been on consistent rise underscoring the critical need for novel diagnostic, prognostic and therapeutic tools for its effective management. Recent studies have demonstrated that microRNAs (miRNAs/miRs) are deregulated in a variety of malignancies, including pancreatic cancer, and play a significant role in the initiation, progression and metastasis. Furthermore, their vital involvement in the therapeutic resistance of cancer has also been established. Hence, there has been enormous interest worldwide in investigating the roles of miRNAs in pancreatic cancer pathogenesis and exploiting their utility for clinical benefit. In this review, we summarize current knowledge on the role of miRNAs in pancreatic cancer and discuss their potential use as diagnostic and prognostic biomarkers, and as novel targets for development of effective therapeutic strategies.

MicroRNA-10b promotes nucleus pulposus cell proliferation through RhoC-Akt pathway by targeting HOXD10 in intervetebral disc degeneration

Aberrant proliferation of nucleus pulposus cell is implicated in the pathogenesis of intervertebral disc degeneration. Recent findings revealed that microRNAs, a class of small noncoding RNAs, could regulate cell proliferation in many pathological conditions. Here, we showed that miR-10b was dramatically upregulated in degenerative nucleus pulposus tissues when compared with nucleus pulposus tissues isolated from patients with idiopathic scoliosis. Moreover, miR-10b levels were associated with disc degeneration grade and downregulation of HOXD10. In cultured nucleus pulposus cells, miR-10b overexpression stimulated cell proliferation with concomitant translational inhibition of HOXD10 whereas restored expression of HOXD10 reversed the mitogenic effect of miR-10b. MiR-10b-mediated downregulation of HOXD10 led to increased RhoC expression and Akt phosphorylation. Either knockdown of RhoC or inhibition of Akt abolished the effect of miR-10b on nucleus pulposus cell proliferation. Taken together, aberrant miR-10b upregulation in intervertebral disc degeneration could contribute to abnormal nucleus pulposus cell proliferation through derepressing the RhoC-Akt pathway by targeting HOXD10. Our study also underscores the potential of miR-10b and the RhoC-Akt pathway as novel therapeutic targets in intervertebral disc degeneration.

MicroRNA-10b overexpression promotes non-small cell lung cancer cell proliferation and invasion

BACKGROUND

miRNAs are a class of small non-coding RNA molecules that play an important role in the pathogenesis of human diseases through negative regulation of gene expression. Although miRNA-10b (miR-10b) has been implicated in other tumors, its role in non-small cell lung cancer (NSCLC) is still unknown. The aim of the present study was to investigate the role of miR-10b in NSCLC.

METHODS

Expression of miR-10b was analyzed in NSCLC cell line A549 by qRT-PCR. Cell viability was evaluated using Cell Counting Kit (CCK)-8. Cell migration and invasion were evaluated by wound healing assay and transwell assays. Cell cycle and apoptosis analyses were performed. Western blotting was used to predicate the target of miR-10b.

RESULTS

The A549 cell line transfected with the miR-10b exhibited significantly increased proliferation, migration, and invasion capacities when compared with the control cells (P < 0.05). Krüppel-like factor 4 (KLF4) may be indirectly targeted by miR-10b during the proliferation increasing of A549 cells.

CONCLUSION

In this study, we found that miR-10b is a tumor enhancer in NSCLC. Thus, miR-10b may represent a potential therapeutic target for NSCLC intervention.