MicroRNA-124 inhibits the proliferation of C6 glioma cells by targeting Smad4

MicroRNA-124-3p targets Sp1 transcription factor to regulate glioma progression in rats

Gliomas are the most prevalent malignancies of the central nervous system (CNS). Downregulation of microRNA‑124 (miR‑124) has been identified in glioma; however, its biological functions in glioma are not yet fully understood. Specificity protein 1 (SP1) is a type of transcription factor that is involved in cancer progression. In this study, we examined the targeting of Sp1 mRNA by miR-124-3p in a rat glioma model. After confirming and selecting the binding of Sp1 to miR-124 with the help of bioinformatics methods, adult male Wistar rats were used to induce glioma by microinjection of 1 × 106 C6 cells into the striatum area of brain. The rats were divided into 3 groups; intact, sham and glioma groups. The presence of glioma was confirmed 21 days after implantation through histological analysis. The expression levels of miR-124 and SP1 genes in the experimental groups were examined using quantitative real-time polymerase chain reaction (qRT-PCR). Our data showed that the expression of miR-124 was significantly downregulated in glioma group compared to the sham and intact group, while the expression of SP1 was significantly upregulated. We found that the expression levels of miR-124 and Sp1 were decreased and increased in C6 cell line compared to the normal brain tissue cell line, respectively. The results indicated that Sp1 was identified as a direct target of miR‑124 through luciferase reporter assays. In summary, this study demonstrated for the first time that miR-124 expression is downregulated and Sp1 expression is upregulated in an animal model of glioma, which, in turn, may be involved in the development of glioma brain cancer.

Role of Extracellular Vesicles in the Progression of Brain Tumors

Brain tumors, and, in particular, glioblastoma (GBM), are among the most aggressive forms of cancer. In spite of the advancement in the available therapies, both diagnosis and treatments are still unable to ensure pathology-free survival of the GBM patients for more than 12-15 months. At the basis of the still poor ability to cope with brain tumors, we can consider: (i) intra-tumor heterogeneity; (ii) heterogeneity of the tumor properties when we compare different patients; (iii) the blood-brain barrier (BBB), which makes difficult both isolation of tumor-specific biomarkers and delivering of therapeutic drugs to the brain. Recently, it is becoming increasingly clear that cancer cells release large amounts of extracellular vesicles (EVs) that transport metabolites, proteins, different classes of RNAs, DNA, and lipids. These structures are involved in the pathological process and characterize any particular form of cancer. Moreover, EVs are able to cross the BBB in both directions. Starting from these observations, researchers are now evaluating the possibility to use EVs purified from organic fluids (first of all, blood and saliva), in order to obtain, through non-invasive methods (liquid biopsy), tumor biomarkers, and, perhaps, also for obtaining nanocarriers for the targeted delivering of drugs.

Astrocytes-Derived Small Extracellular Vesicles Hinder Glioma Growth

All cells are capable of secreting extracellular vesicles (EVs), which are not a means to eliminate unneeded cellular compounds but represent a process to exchange material (nucleic acids, lipids and proteins) between different cells. This also happens in the brain, where EVs permit the crosstalk between neuronal and non-neuronal cells, functional to homeostatic processes or cellular responses to pathological stimuli. In brain tumors, EVs are responsible for the bidirectional crosstalk between glioblastoma cells and healthy cells, and among them, astrocytes, that assume a pro-tumoral or antitumoral role depending on the stage of the tumor progression. In this work, we show that astrocyte-derived small EVs (sEVs) exert a defensive mechanism against tumor cell growth and invasion. The effect is mediated by astrocyte-derived EVs (ADEVs) through the transfer to tumor cells of factors that hinder glioma growth. We identified one of these factors, enriched in ADEVs, that is miR124. It reduced both the expression and function of the volume-regulated anion channel (VRAC), that, in turn, decreased the cell migration and invasion of murine glioma GL261 cells.

miR-124: A Promising Therapeutic Target for Central Nervous System Injuries and Diseases

Central nervous system injuries and diseases, such as ischemic stroke, spinal cord injury, neurodegenerative diseases, glioblastoma, multiple sclerosis, and the resulting neuroinflammation often lead to death or long-term disability. MicroRNAs are small, non-coding, single-stranded RNAs that regulate posttranscriptional gene expression in both physiological and pathological cellular processes, including central nervous system injuries and disorders. Studies on miR-124, one of the most abundant microRNAs in the central nervous system, have shown that its dysregulation is related to the occurrence and development of pathology within the central nervous system. Herein, we review the molecular regulatory functions, underlying mechanisms, and effective delivery methods of miR-124 in the central nervous system, where it is involved in pathological conditions. The review also provides novel insights into the therapeutic target potential of miR-124 in the treatment of human central nervous system injuries or diseases.

Prognostic Potential of MicroRNAs in Glioma Patients: A Meta-Analysis

Introduction MicroRNAs are a noncoding RNA involved in affecting several transcription and translation pathways. Their use has been discussed as potential predictors of several tumors. Their use as potential biomarker in glioma patients is still controversial. The purpose of this meta-analysis is to explore the possible role of such microRNAs in glioma patients.

Methods After an extensive literature search done on PubMed and Embase, 20 studies were chosen for our analyses with the 9 discussing 11 tumor promoting microRNAs and 11 studies discussing 11 tumor suppressing microRNAs. The data needed was extracted from these studies including the hazard ratio that was used as the effect size for the purpose of our analysis. The needed analysis was performed using Stata and Excel.

Results The pooled hazard ratio for our analysis with patients having a lower microRNA expression for tumor promoting microRNAs came to be 2.63 (p < 0.001), while the hazard ratio for patients with higher expression of tumor promoting microRNA was 2.47 (p < 0.001) with both results being statistically significant. However, as significant heterogeneity was observed a random effect model for analysis was used. Subgroup analysis was further performed using grade, cutoff value (mean or median), sample type (Serum or Blood), and Karnofsky performance score, all of them showing a high hazard ratio.

Conclusion Our results showed that both tumor inhibitory and promoting microRNA can be used as prognostic tool in glioma patients with a poorer prognosis associated with a lower expression in tumor suppressive and higher expression in tumor promoting microRNA, respectively. However, to support this, future studies on a much larger scale would be needed.

Noncoding RNAs involved in the STAT3 pathway in glioma

Glioma is the most common malignant primary brain tumour in adults. Despite improvements in neurosurgery and radiotherapy, the prognosis of glioma patients remains poor. One of the main limitations is that there are no proper clinical therapeutic targets for glioma. Therefore, it is crucial to find one or more effective targets. Signal transducer and activator of transcription 3 (STAT3) is a member of the STAT family of genes. Abnormal expression of STAT3 is involved in the process of cell proliferation, migration, invasion, immunosuppression, angiogenesis, dryness maintenance, and resistance to radiotherapy and chemotherapy in glioma. Therefore, STAT3 has been considered an ideal therapeutic target in glioma. Noncoding RNAs (ncRNAs) are a group of genes with limited or no protein-coding capacity that can regulate gene expression at the epigenetic, transcriptional and posttranscriptional level. In this review, we summarized the ncRNAs that are correlated with the ectopic expression of STAT3 in glioma.

MiR-26a-5p alleviates cardiac hypertrophy and dysfunction via targeting ADAM17

Cardiac hypertrophy has been a high prevalence rate throughout the world. It has posed a big threat to public health due to limited therapeutic approaches. Previous studies showed that pathological cardiac hypertrophy was associated with autophagy, microRNAs (miRNA), and other signaling pathways, while the molecular mechanisms remain incompletely characterized. In this study, we used thoracic aortic constriction (TAC)-induced mice and angiotensin-II (Ang-II)-induced H9C2 cell line as cardiac hypertrophy model to investigate the role of miR-26a-5p in cardiac hypertrophy. We found that miR-26a-5p was downregulated in cardiac hypertrophy mice. Overexpression of miR-26a-5p by type 9 recombinant adeno-associated virus (rAAV9) reversed the heart hypertrophic manifestations. The phenotypes were also promoted by miR-26a-5p inhibitor in Ang-II-induced H9C2 cells. Through miRNA profile analysis and dual-luciferase reporter assay, ADAM17 was identified as a direct target of miR-26a-5p. Restored expression of ADAM17 disrupted the effect of miR-26a-5p on cardiac hypertrophy. To sum up, these results indicated that miR-26a-5p played an inhibitory role in cardiac hypertrophy and dysfunction via targeting ADAM17. The miR-26a-5p-ADAM17-cardiac hypertrophy axis provided special insight and a new molecular mechanism for a better understanding of cardiac hypertrophy disease, as well as the diagnostic and therapeutic practice.

MiR-124 and Small Molecules Synergistically Regulate the Generation of Neuronal Cells from Rat Cortical Reactive Astrocytes

Irreversible neuron loss caused by central nervous system injuries usually leads to persistent neurological dysfunction. Reactive astrocytes, because of their high proliferative capacity, proximity to neuronal lineage, and significant involvement in glial scarring, are ideal starting cells for neuronal regeneration. Having previously identified several small molecules as important regulators of astrocyte-to-neuron reprogramming, we established herein that miR-124, ruxolitinib, SB203580, and forskolin could co-regulate rat cortical reactive astrocyte-to-neuron conversion. The induced cells had reduced astroglial properties, displayed typical neuronal morphologies, and expressed neuronal markers, reflecting 25.9% of cholinergic neurons and 22.3% of glutamatergic neurons. Gene analysis revealed that induced neuron gene expression patterns were more similar to that of primary neurons than of initial reactive astrocytes. On the molecular level, miR-124-driven neuronal differentiation of reactive astrocytes was via targeting of the SOX9-NFIA-HES1 axis to inhibit HES1 expression. In conclusion, we present a novel approach to inducing endogenous rat cortical reactive astrocytes into neurons through co-regulation involving miR-124 and three small molecules. Thus, our research has potential implications for inhibiting glial scar formation and promoting neuronal regeneration after central nervous system injury or disease.

The Effect of Melatonin Modulation of Non-coding RNAs on Central Nervous System Disorders: An Updated Review

Melatonin is a hormone produced in and secreted by the pineal gland. Besides its role in regulating circadian rhythms, melatonin has a wide range of protective functions in the central nervous system (CNS) disorders. The mechanisms underlying this protective function are associated with the regulatory effects of melatonin on related genes and proteins. In addition to messenger ribonucleic acid (RNA) that can be translated into protein, an increasing number of non-coding RNAs in the human body are proven to participate in many diseases. This review discusses the current progress of research on the effects of melatonin modulation of non-coding RNAs (ncRNAs), including microRNA, long ncRNA, and circular RNA. The role of melatonin in regulating common pathological mechanisms through these ncRNAs is also summarized. Furthermore, the ncRNAs, currently shown to be involved in melatonin signaling in CNS diseases, are discussed. The information compiled in this review will open new avenues for future research into melatonin mechanisms and provide a further understanding of ncRNAs in the CNS.

Epigenetics of glioblastoma multiforme: From molecular mechanisms to therapeutic approaches

Glioblastoma multiforme (GBM) is the most common form of brain cancer and one of the most aggressive cancers found in humans. Most of the signs and symptoms of GBM can be mild and slowly aggravated, although other symptoms might demonstrate it as an acute ailment. However, the precise mechanisms of the development of GBM remain unknown. Due to the improvement of molecular pathology, current researches have reported that glioma progression is strongly connected with different types of epigenetic phenomena, such as histone modifications, DNA methylation, chromatin remodeling, and aberrant microRNA. Furthermore, the genes and the proteins that control these alterations have become novel targets for treating glioma because of the reversibility of epigenetic modifications. In some cases, gene mutations including P16, TP53, and EGFR, have been observed in GBM. In contrast, monosomies, including removals of chromosome 10, particularly q23 and q25-26, are considered the standard markers for determining the development and aggressiveness of GBM. Recently, amid the epigenetic therapies, histone deacetylase inhibitors (HDACIs) and DNA methyltransferase inhibitors have been used for treating tumors, either single or combined. Specifically, HDACIs are served as a good choice and deliver a novel pathway to treat GBM. In this review, we focus on the epigenetics of GBM and the consequence of its mutations. We also highlight various treatment approaches, namely gene editing, epigenetic drugs, and microRNAs to combat GBM.

miR-486 is involved in the pathogenesis of acute myeloid leukemia by regulating JAK-STAT signaling

Acute myeloid leukemia (AML) is a widely prevalent disease worldwide and poses a large threat to public health. Previous studies have shown that AML is associated with cytogenetic heterogeneity, complex subtypes, and different therapeutic approaches. In this study, we found that miR-486 was upregulated in AML using both The Cancer Genome Atlas (TCGA) database and patient tissues. After knockdown of miR-486 by short hairpin RNA (shRNA), we discovered that miR-486 was required for cell proliferation. Through miRNA profile analysis and a dual-luciferase reporter assay, suppressor of cytokine signaling 2 (SOCS2) was identified as a direct target of miR-486. Therefore, by silencing SOCS2, a negative regulator of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway, miR-486 enhanced JAK-STAT3 activity and promoted cell proliferation. The miR-486-SOCS2-STAT3 proliferation axis is therefore involved in the pathogenesis of AML, providing a novel molecular mechanism and diagnostic and therapeutic clues for AML.

p62 acts as an oncogene and is targeted by miR-124-3p in glioma

Background

Glioma is the most common central nervous system (CNS) tumour. p62, an important autophagy adaptor, plays a crucial role in cancer. However, the role of p62 in the progression of glioma is poorly characterized.

Methods

We examined the expression of p62 in glioma tissues and cell lines. Then we investigated the function of p62 in vitro, and clarified the mechanism underlying the regulation of p62 expression.

Results

We revealed that p62 was upregulated at both the mRNA and protein levels in human glioma tissues irrelevant to isocitrate dehydrogenase (IDH) status. Then, we found that overexpression of p62 promoted glioma progression by promoting proliferation, migration, glycolysis, temozolomide (TMZ) resistance and nuclear factor κB (NF-κB) signalling pathway, and repressing autophagic flux and reactive oxygen species (ROS) in vitro. In accordance with p62 overexpression, knockdown of p62 exerted anti-tumour effects in glioma cells. Subsequently, we demonstrated that miR-124-3p directly targeted the 3′-UTR of p62 mRNA, leading to the downregulation of p62. Finally, we found that p62 function could be partially reversed by miR-124-3p overexpression.

Conclusions

Our results demonstrate that p62 can be targeted by miR-124-3p and acts as an oncogene in glioma, suggesting the potential value of p62 as a novel therapeutic target for glioma.

MicroRNAs play an important role in contributing to arsenic susceptibility in the chronically exposed individuals of West Bengal, India

Arsenic exposure by groundwater contamination is a menace which threatens more than 26 million individuals of West Bengal. Interestingly, with similar levels of arsenic exposure, only 15-20% of the population show arsenic-induced skin lesions, the hallmarks of chronic arsenic toxicity, but the rest do not. In this study, our aim was to identify whether microRNAs (miRNA) have any role to play in causing such arsenic susceptibility. Global plasma miRNA profiling was done in 12 arsenic-exposed individuals with skin lesions and 12 exposed individuals without skin lesions. Two hundred two miRNAs were found to be differentially regulated between the two study groups. Results were validated by quantitative real-time PCR in 30 exposed subjects from each of the groups, which showed that among others miR-21, miR-23a, miR-27a, miR-122, miR-124, miR-126, miR-619, and miR-3613 were significantly upregulated and miR-1282 and miR-4530 were downregulated in the skin lesion group compared with the no skin lesion group. Bioinformatic analyses predicted that these altered miRNAs have targets in 7 different biochemical pathways, including glycerophospholipid metabolism, colorectal cancer, glycosphingolipid biosynthesis, T cell receptor signaling, and neurotrophin signaling pathways; glycerophospholipid metabolism pathway being the most enriched pathway. Association study show that these microRNAs contribute significantly to the increased prevalence of other non-dermatological health effects like conjunctival irritations of the eyes and respiratory distress in the study subjects. To our knowledge, this is the first study of its kind involving miRNA expressions contributing to arsenic susceptibility in the exposed population of West Bengal.

STC1 regulates glioblastoma migration and invasion via the TGF‑β/SMAD4 signaling pathway

Stanniocalcin-1 (STC1) is involved in cancer progression; however, the function of STC1 in glioblastoma remains unknown. In the present study, the expression levels of STC1 protein in glioblastoma were detected using immunohistochemistry. The expression levels of STC1, SMAD2/3 and SMAD4 proteins, following silencing of STC1, were assessed via western blotting. EdU and Transwell assays were performed to determine the proliferation and migration ability of the cells. The mRNA expression levels of STC1, SMAD4 and microRNA (miR)-34a were determined using quantitative PCR. The expression levels of STC1 were increased in glioblastoma tissues. STC1 revealed a significant association with poor outcome in patients with glioblastoma (P<0.05). The proliferation and invasion abilities were repressed in LN229 cells infected with LV3-shSTC1-1 and LV3-shSTC1-2 compared with LV3-NC. By contrast, the proliferation and invasion abilities were increased in T98G cells infected with LV5-STC1 compared with LV5-NC (P<0.05). The expression levels of STC1, SMAD2/3 and SMAD4 were decreased in LN229 cells infected with LV3-shSTC1-1 and LV3-shSTC1-2 compared with LV3-NC. However, the expression levels of STC1, SMAD2/3 and SMAD4 were elevated in T98G cells infected with LV5-STC1 compared with LV5-NC. The expression levels of miR-34a were decreased following silencing of STC1 (P<0.05). The expression levels of SMAD4 were decreased when transfected with miR-34a mimics (P<0.05). The luciferase activity of the wild-type 3′untranslated region of SMAD4 was decreased following transfection with miR-34a mimics (P<0.05). Silencing of STC1 inhibited the growth of LN229 in vivo. In conclusion, STC1 expression levels were increased in the present study, and it was revealed that STC1 regulated glioblastoma malignancy. This phenotype was observed in the SMAD2/3 and SMAD4 pathways.

MicroRNA‑124 negatively regulates chloride intracellular channel 1 to suppress the migration and invasion of liver cancer cells

The dysregulation of microRNAs (miRNAs) is associated with the development and progression of a variety of cancers, including liver cancer. Aberrant expression of miRNA (miR)-124 has been demonstrated in liver cancer, but its functional mechanism in liver cancer is still largely unknown. Metastasis of liver cancer is one of the most common causes of mortality. The present study showed that miR-124 inhibited the proliferation, migration and invasion of liver cancer cells. Furthermore, chloride intracellular channel 1 (CLIC1) was identified as a novel target of miR-124 in liver cancer cells. Overexpression of miR-124 reduced CLIC1 expression at both the protein and mRNA levels in liver cancer cells. Downregulation of CLIC1 decreased the migration and invasion of liver cancer cells without affecting cell proliferation. Taken together, these results showed that CLIC1 is a critical target for miR-124-mediated inhibitory effects on cell migration and invasion. Thus, miR-124 or suppression of CLIC1 may have diagnostic value and therapeutic potential for the treatment of human liver cancer.

Personalized regulation of glioblastoma cancer stem cells based on biomedical technologies: From theory to experiment (Review)

Glioblastoma multiforme (GBM) is one of the most aggressive brain tumors. GBM represents >50% of primary tumors of the nervous system and ~20% of intracranial neoplasms. Standard treatment involves surgery, radiation and chemotherapy. However, the prognosis of GBM is usually poor, with a median survival of 15 months. Resistance of GBM to treatment can be explained by the presence of cancer stem cells (CSCs) among the GBM cell population. At present, there are no effective therapeutic strategies for the elimination of CSCs. The present review examined the nature of human GBM therapeutic resistance and attempted to systematize and put forward novel approaches for a personalized therapy of GBM that not only destroys tumor tissue, but also regulates cellular signaling and the morphogenetic properties of CSCs. The CSCs are considered to be an informationally accessible living system, and the CSC proteome should be used as a target for therapy directed at suppressing clonal selection mechanisms and CSC generation, destroying CSC hierarchy, and disrupting the interaction of CSCs with their microenvironment and extracellular matrix. These objectives can be achieved through the use of biomedical cellular products.

Molecular Determinants of Malignant Brain Cancers: From Intracellular Alterations to Invasion Mediated by Extracellular Vesicles

Malignant glioma cells invade the surrounding brain parenchyma, by migrating along the blood vessels, thus promoting cancer growth. The biological bases of these activities are grounded in profound alterations of the metabolism and the structural organization of the cells, which consequently acquire the ability to modify the surrounding microenvironment, by altering the extracellular matrix and affecting the properties of the other cells present in the brain, such as normal glial-, endothelial- and immune-cells. Most of the effects on the surrounding environment are probably exerted through the release of a variety of extracellular vesicles (EVs), which contain many different classes of molecules, from genetic material to defined species of lipids and enzymes. EV-associated molecules can be either released into the extracellular matrix (ECM) and/or transferred to neighboring cells: as a consequence, both deep modifications of the recipient cell phenotype and digestion of ECM components are obtained, thus causing cancer propagation, as well as a general brain dysfunction. In this review, we first analyze the main intracellular and extracellular transformations required for glioma cell invasion into the brain parenchyma; then we discuss how these events may be attributed, at least in part, to EVs that, like the pawns of a dramatic chess game with cancer, open the way to the tumor cells themselves.