MicroRNA in radiotherapy: miRage or miRador?

At least half of all cancer patients will receive radiation therapy. Tumour radioresistance, or the failure to control certain tumours with this treatment, can result in locoregional recurrence; thus there is great interest in understanding the underlying biology and developing strategies to overcome this problem. The expanding investigation of microRNA in cancer suggests that these regulatory factors can influence the DNA damage response, the microenvironment and survival pathways, among other processes, and thereby may affect tumour radioresistance. As microRNA are readily detectable in tumours and biofluids, they hold promise as predictive biomarkers for therapy response and prognosis. This review highlights the current insights on the major ways that microRNA may contribute to tumour radiation response and whether their levels reflect treatment success. We conclude by applying the potential framework of future roles of miR in personalised radiotherapy using prostate cancer clinical management as an example.     

microRNA-423-3p promotes tumor progression via modulation of AdipoR2 in laryngeal carcinoma

Despite of the variety of combined modality treatments for laryngeal carcinoma have been introduced, the distance recurrence rate and 5-year overall survival rate over the past decades are still the major issues, underlining the importance to better understand the biological bases that contribute to disease progression. Here, we reported that miR-423-3p overexpressed in primary laryngeal carcinoma cell line where it plays a critical role in tumor progression. Suppression of miR-423-3p expression resulted in decreasing cell proliferation, clonogenicity, cell migration and invasion. By using in silico prediction algorithms for target identification, AdipoR2 (adiponectin receptor 2) and DUSP4 (MAP kinase phosphatase 2) were identified to be potential targets of miR-423-3p. Overexpression of miR-423-3p was associated with epigenetic silencing of AdipoR2 in human laryngeal carcinoma samples, which have been previously implicated in suppression of tumor proliferation and angiogenesis. Luciferase reporter assays and western blot further confirmed the direct interaction of miR-423-3p with AdipoR2. Our findings have demonstrated that miR-423-3p plays an important oncogenic role in laryngeal carcinoma progression, and further suggest that suppression of miR-423-3p expression might be useful for its clinical management.     

miR-320c Regulates SERPINA1 Expression and Is Induced in Patients With Pulmonary Disease

IntroductionAlpha-1 antitrypsin deficiency (AATD) is a genetic condition resulting in lung and liver disease with a great clinical variability. MicroRNAs have been identified as disease modifiers; therefore miRNA deregulation could play an important role in disease heterogeneity. Members of miR-320 family are involved in regulating of multiple processes including inflammation, and have potential specific binding sites in the 3′UTR region of SERPINA1 gene. In this study we explore the involvement of miR-320c, a member of this family, in this disease.MethodsFirstly in vitro studies were carried out to demonstrate regulation of SERPINA1 gene by miR-320. Furthermore, the expression of miR-320c was analyzed in the blood of 98 individuals with different AAT serum levels by using quantitative PCR and expression was correlated to clinical parameters of the patients. Finally, HL60 cells were used to analyze induction of miR-320c in inflammatory conditions.ResultsOverexpression of miR-320 members in human HepG2 cells led to inhibition of SERPINA1 expression. Analysis of miR-320c expression in patient's samples revealed significantly increased expression of miR-320c in individuals with pulmonary disease. Additionally, HL60 cells treated with the pro-inflammatory factor lipopolysaccharide (LPS) showed increase in miR-320c expression, suggesting that miR-320c responds to inflammation.ConclusionOur findings demonstrate that miR-320c inhibits SERPINA1 expression in a hepatic cell line and its levels in blood are associated with lung disease in a cohort of patients with different AAT serum levels. These results suggest that miR-320c can play a role in AAT regulation and could be a biomarker of inflammatory processes in pulmonary diseases.     

Plasma microRNAs as biomarkers for myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) lacks non-invasive and easy to measure biomarkers, still largely relying on semi-quantitative tests for diagnostic and prognostic purposes. Muscle biopsies provide valuable data, but their use is limited by their invasiveness. microRNA (miRNAs) are small non-coding RNAs regulating gene expression that are also present in biological fluids and may serve as diseases biomarkers. Thus, we tested plasma miRNAs in the blood of 36 DM1 patients and 36 controls. First, a wide miRNA panel was profiled in a patient subset, followed by validation using all recruited subjects. We identified a signature of nine deregulated miRNAs in DM1 patients: eight miRNAs were increased (miR-133a, miR-193b, miR-191, miR-140-3p, miR-454, miR-574, miR-885-5p, miR-886-3p) and one (miR-27b) was decreased. Next, the levels of these miRNAs were used to calculate a “DM1-miRNAs score”. We found that both miR-133a levels and DM1-miRNAs score discriminated DM1 from controls significantly and Receiver–Operator Characteristic curves displayed an area under the curve of 0.94 and 0.97, respectively. Interestingly, both miR-133a levels and DM1-miRNAs score displayed an inverse correlation with skeletal muscle strength and displayed higher values in more compromised patients.In conclusion, we identified a characteristic plasma miRNA signature of DM1. Although preliminary, this study indicates miRNAs as potential DM1 humoral biomarkers.     

Long-term epigenetic alterations in a rat model of Gulf War Illness

Gulf War Illness (GWI) is a chronic, multisymptom illness that affects 25% of the 700,000 US veterans deployed to the Persian Gulf during the 1990–1991 Gulf War. Central nervous system impairments are among the most common symptoms reported, including memory dysfunction and depression. After 25 years, the diagnosis remains elusive, useful treatments are lacking, and the cause is poorly understood, although exposures to pyridostigmine bromide (PB) and pesticides are consistently identified to be among the strongest risk factors. Epigenetic changes including altered microRNA (miRNA) expression and DNA methylation play an important role in learning, memory, and emotion regulation and have been implicated in various neurological disorders. In this study, we used an established rat model of GWI to determine whether 1) chronic alterations in miRNA expression and global DNA methylation and DNA hydroxymethylation are mechanisms involved in the pathobiology of GWI, and 2) plasma exosome small RNAs may serve as potential noninvasive biomarkers of this debilitating disease. One year after a 28-day exposure regimen of PB, DEET (N,N-diethyl-3-methylbenzamide), permethrin, and mild stress, expression of 84 mature miRNAs and global 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) content were analyzed in the brains of GWI rats and vehicle controls by PCR array and enzyme-linked immunosorbent assay, respectively. Plasma exosome RNA next-generation sequencing analysis was performed in pooled samples to discover potential noninvasive biomarkers. We found that combined exposure to low doses of GW-related chemicals and mild stress caused epigenetic modifications in the brain that persisted one year after exposure, including increased expression of miR-124-3p and miR-29b-3p in the hippocampus and regional alterations in global 5mC and 5hmC content. GW-relevant exposures also induced the differential expression of two piwi-interacting RNAs (piRNAs) in circulation (piR-007899 and piR-019162). Results from this study implicate a role for epigenetic alterations in GWI. Evaluation of the diagnostic potential of plasma exosome RNAs in veterans with GWI is warranted.     

MicroRNAs in hematological malignancies

MicroRNAs (miRNAs) have become one of the hottest topics in biology over recent years, but remarkably have only been formally recognized for just over 10 years. These endogenously produced short (19–24 nt) non-coding RNAs have introduced an entirely new paradigm in our understanding of gene control and it is now evident that miRNAs play a crucial regulatory role in many, if not all, physiological and pathological processes. In this review we provide an overview of the role and potential clinical utility for miRNAs in hematological malignancies and their function in normal hematopoiesis. Although still in its infancy, the miRNA field has already added much to our understanding of hematological processes, and provides us with novel tools as both biomarkers and therapeutic agents for hematological malignancies.     

Helicobacter pylori induces caudal‐type homeobox protein 2 and cyclooxygenase 2 expression by modulating microRNAs in esophageal epithelial cells

Dysregulation of microRNAs (miRNAs) has been linked to virulence factors of Helicobacter pylori. The role of H. pylori in esophageal disease has not been clearly defined. We previously reported that H. pylori esophageal colonization promotes the incidence of Barrett's esophagus and esophageal adenocarcinoma in vivo. Here, we studied the direct effects of H. pylori on the transformation of esophageal epithelial cells, with particular focus on whether H. pylori exerts its effects by modulating miRNAs and their downstream target genes. The normal human esophageal cell line HET‐1A was chronically exposed to H. pylori extract and/or acidified deoxycholic acid for up to 36 weeks. The miRNA profiles of the esophageal epithelial cells associated with H. pylori infection were determined by microarray analysis. We found that chronic H. pylori exposure promoted acidified deoxycholic acid‐induced morphological changes in HET‐1A cells, along with aberrant overexpression of intestinal metaplasia markers and tumorigenic factors, including caudal‐type homeobox protein 2 (CDX2), mucin 2, and cyclooxygenase 2 (COX2). Helicobacter pylori modified the miRNA profiles of esophageal epithelial cells, particularly aberrant silencing of miR‐212‐3p and miR‐361‐3p. Moreover, in biopsies from Barrett's esophagus patients, esophageal H. pylori colonization was associated with a significant decrease in miR‐212‐3p and miR‐361‐3p expression. Furthermore, we identified COX2 as a target of miR‐212‐3p, and CDX2 as a target of miR‐361‐3p. Helicobacter pylori infection of esophageal epithelial cells was associated with miRNA‐mediated upregulation of oncoprotein CDX2 and COX2. Our observations provide new evidence about the molecular mechanisms underlying the association between H. pylori infection and esophageal carcinogenesis.     

Tumor Epigenetic Signature and Survival in Resected Gastric Cancer Patients

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