High-throughput microRNA (miRNAs) arrays unravel the prognostic role of MiR-211 in pancreatic cancer

Novel blood-based microRNA biomarker panel for early diagnosis of pancreatic cancer

AIM: To develop a panel of blood-based diagnostic biomarkers consisting of circulating microRNAs for the detection of pancreatic cancer at an early stage.

METHODS: Blood-based circulating microRNAs were profiled by high throughput screening using microarray analysis, comparing differential expression between early stage pancreatic cancer patients (n = 8) and healthy controls (n = 11). A panel of candidate microRNAs was generated based on the microarray signature profiling, including unsupervised clustering and statistical analysis of differential expression levels, and findings from the published literature. The selected candidate microRNAs were then confirmed using TaqMan real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) to further narrow down to a three-microRNA diagnostic panel. The three-microRNA diagnostic panel was validated with independent experimental procedures and instrumentation of RT-qPCR at an independent venue with a new cohort of cancer patients (n = 11), healthy controls (n = 11), and a group of high risk controls (n = 11). Receiver operating characteristic curve analysis was performed to assess the diagnostic capability of the three-microRNA panel.

RESULTS: In the initial high throughput screening, 1220 known human microRNAs were screened for differential expression in pancreatic cancer patients versus controls. A subset of 42 microRNAs was then generated based on this data analysis and current published literature. Eight microRNAs were selected from the list of 42 targets for confirmation study, and three-microRNAs, miR-642b, miR-885-5p, and miR-22, were confirmed to show consistent expression between microarray and RT-qPCR. These three microRNAs were then validated and evaluated as a diagnostic panel with a new cohort of patients and controls and found to yield high sensitivity (91%) and specificity (91%) with an area under the curve of 0.97 (P < 0.001). Compared to the CA19-9 marker at 73%, the three-microRNA panel has higher sensitivity although CA19-9 has higher specificity of 100%.

CONCLUSION: The identified panel of three microRNA biomarkers can potentially be used as a diagnostic tool for early stage pancreatic cancer.

Interfacing polymeric scaffolds with primary pancreatic ductal adenocarcinoma cells to develop 3D cancer models

We analyzed the interactions between human primary cells from pancreatic ductal adenocarcinoma (PDAC) and polymeric scaffolds to develop 3D cancer models useful for mimicking the biology of this tumor. Three scaffold types based on two biocompatible polymeric formulations, such as poly(vinyl alcohol)/gelatin (PVA/G) mixture and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymer, were obtained via different techniques, namely, emulsion and freeze-drying, compression molding followed by salt leaching, and electrospinning. In this way, primary PDAC cells interfaced with different pore topographies, such as sponge-like pores of different shape and size or nanofiber interspaces. The aim of this study was to investigate the influence played by the scaffold architecture over cancerous cell growth and function. In all scaffolds, primary PDAC cells showed good viability and synthesized tumor-specific metalloproteinases (MMPs) such as MMP-2, and MMP-9. However, only sponge-like pores, obtained via emulsion-based and salt leaching-based techniques allowed for an organized cellular aggregation very similar to the native PDAC morphological structure. Differently, these cell clusters were not observed on PEOT/PBT electrospun scaffolds. MMP-2 and MMP-9, as active enzymes, resulted to be increased in PVA/G and PEOT/PBT sponges, respectively. These findings suggested that spongy scaffolds supported the generation of pancreatic tumor models with enhanced aggressiveness. In conclusion, primary PDAC cells showed diverse behaviors while interacting with different scaffold types that can be potentially exploited to create stage-specific pancreatic cancer models likely to provide new knowledge on the modulation and drug susceptibility of MMPs.

miR-211 modulates gemcitabine activity through downregulation of ribonucleotide reductase and inhibits the invasive behavior of pancreatic cancer cells

Only a subset of radically-resected pancreatic ductal adenocarcinoma (PDAC) patients benefit from gemcitabine-based chemotherapy, thus the identification of novel prognostic factors is essential. In a high-throughput, microRNA (miRNA) array, miR-211 emerged as the best discriminating miRNA, with high expression associated with long survival. Here, we further explored the biological role of miRNA-211 in gemcitabine activity in the human PDAC cells (SUIT-2) subclones SUIT2-007 and SUIT2-028. Our results showed that miR-211 was expressed differentially in PDAC cells characterized by differential metastatic capability. In particular, S2-028 with lower metastatic ability had a higher expression of miR-211, compared to the S2-007 with higher metastatic capacity. Enforced expression of miR-211 via pre-miR-211 significantly reduced cell migration and invasion (e.g., 40% reduction of invasion of SUIT2 cells, compared to control; p<.05). Moreover, we demonstrated that induction of the miR-211 expression in the cells increased the sensitivity to gemcitabine and reduced the expression of its target ribonucleotide reductase subunit 2 (RRM2). In conclusion, miR-211 functional analyses suggested the role of RRM2 as a target of miR-211 in the modulation of gemcitabine sensitivity. Moreover, inhibition of cell migration and invasion might explain the less aggressive behavior of pancreatic cancer cells with higher expression levels of miR-211.

Upregulation of miR-194 contributes to tumor growth and progression in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of human cancer worldwide. In the present study, we investigated the diagnostic and biological significance of microRNA-194 (miR-194) in PDAC. miRNA expression profiling of human PDACs and adjacent normal pancreatic tissues identified a total of 16 genes including miR-194 with >1.15-fold expression changes (8 overexpressed and 8 underexpressed). Quantitative real-time polymerase chain reaction (PCR) revealed elevation of serum miR-194 levels were significantly greater in PDAC patients than in duodenal adenocarcinoma patients and healthy controls. Receiver operating characteristic analysis demonstrated that serum miR-194 had a sensitivity of 54.3% and a specificity of 57.5% for discriminating PDAC patients from healthy controls. Combined analysis of the 3 groups yielded a sensitivity of 84.0 and a specificity of 75.0% for the combined detection of miR-192 and miR-194 in the diagnosis of PDAC. Ectopic expression of miR-194 in PANC-1 pancreatic cancer cells enhanced cell proliferation, migration and colony formation, which was coupled with decreased expression of the tumor suppressor DACH1. miR-194 overexpression increased tumor growth and local invasion and suppressed the expression of DACH1 in an orthotopic pancreatic cancer mouse model. In conclusion, upregulation of miR-194 contributes to tumor growth and progression in PDAC, possibly through suppression of DACH1. However, serum miR-194 has a low capacity for detection of PDAC. Combined detection of serum miR-192 and miR-194 levels may serve as a sensitive diagnostic biomarker for PDAC.

Genetic and molecular alterations in pancreatic cancer: implications for personalized medicine

Recent advances in human genomics and biotechnologies have profound impacts on medical research and clinical practice. Individual genomic information, including DNA sequences and gene expression profiles, can be used for prediction, prevention, diagnosis, and treatment for many complex diseases. Personalized medicine attempts to tailor medical care to individual patients by incorporating their genomic information. In a case of pancreatic cancer, the fourth leading cause of cancer death in the United States, alteration in many genes as well as molecular profiles in blood, pancreas tissue, and pancreas juice has recently been discovered to be closely associated with tumorigenesis or prognosis of the cancer. This review aims to summarize recent advances of important genes, proteins, and microRNAs that play a critical role in the pathogenesis of pancreatic cancer, and to provide implications for personalized medicine in pancreatic cancer.

Expression of microRNA-218 in human pancreatic ductal adenocarcinoma and its correlation with tumor progression and patient survival

BACKGROUND

Our aim was to analyze clinicopathologic and prognostic values of microRNA (miR)-218 in pancreatic ductal adenocarcinima (PDAC).

METHODS

TaqMan quantitative RT-PCR was used to determine the expression of miR-218 in human PDAC cells and tissue samples. The association of miR-218 expression with clinicopathologic variables was analyzed. Kaplan-Meier survival analysis was performed to analyze the association of miR-218 expression with recurrence-free survival or overall survival of patients. Univariate and multivariate Cox regression analyses were performed.

RESULTS

The relative level of miR-218 in PDAC cells was significantly lower than that in normal human pancreatic duct epithelial cell line. Also, the mean level of miR-218 in PDAC tissues was significantly lower than that in normal pancreatic tissues. Statistical analyses indicated that low miR-218 expression was closely associated with poor tumor differentiation, advanced tumor stage, higher incidence of lymph node metastasis, and tumor recurrence. Kaplan-Meier survival analyses showed that patients with low miR-218 expression had lower recurrence-free and overall survival than those with high miR-218 expression. Univariate and multivariate Cox regression analyses showed that miR-218 might be an independent prognostic factor.

CONCLUSION

Reduced miR-218 in PDAC tissues was correlated with tumor progression, and might be an independent poor prognostic factor for patients.

Non-coding RNAs in muscle dystrophies

ncRNAs are the most recently identified class of regulatory RNAs with vital functions in gene expression regulation and cell development. Among the variety of roles they play, their involvement in human diseases has opened new avenues of research towards the discovery and development of novel therapeutic approaches. Important data come from the field of hereditary muscle dystrophies, like Duchenne muscle dystrophy and Myotonic dystrophies, rare diseases affecting 1 in 7000-15,000 newborns and is characterized by severe to mild muscle weakness associated with cardiac involvement. Novel therapeutic approaches are now ongoing for these diseases, also based on splicing modulation. In this review we provide an overview about ncRNAs and their behavior in muscular dystrophy and explore their links with diagnosis, prognosis and treatments, highlighting the role of regulatory RNAs in these pathologies.

microRNA-7 suppresses the invasive potential of breast cancer cells and sensitizes cells to DNA damages by targeting histone methyltransferase SET8

SET8 (SET domain containing 8) is a histone H4 lysine 20 (H4K20)-specific monomethyltransferase in higher eukaryotes that exerts diverse functions in transcription regulation, DNA repair, tumor metastasis, and genome integrity. The activity of SET8 is tightly controlled during cell cycle through post-translational modifications, including ubiquitination, phosphorylation, and sumoylation. However, how the expression of SET8 is regulated is not fully understood. Here, we report that microRNA-7 is a negative regulator of SET8. We demonstrated that microRNA-7 inhibits H4K20 monomethylation and suppresses epithelial-mesenchymal transition and the invasive potential of breast cancer cells. We showed that microRNA-7 promotes spontaneous DNA damages and sensitizes cells to induced DNA damages. Our experiments provide a molecular mechanism for the regulation of SET8 and extend the biological function of microRNA-7 to DNA damage response, supporting the pursuit of microRNA-7 as a potential target for breast cancer intervention.