A 4-miRNAs signature predicts survival in glioblastoma multiforme patients

[Patients with long-term survival in malignant gliomas after photodynamic therapy]

OBJECTIVE

Analysis of long-lived patients from the group of patients with glioblastomas after using photodynamic therapy in the structure of their complex treatment in order to assess the influence of various factors on their life expectancy.

MATERIAL AND METHODS

In total, a single-center, retrospective categorical study analyzed the long-term results of treatment of 63 patients with glioblastoma in the structure of complex treatment including photodynamic therapy. Clinical factors (age, sex, number of cases, preoperative Karnofsky index, location and size of the tumor, radicality of the operation), histological (nuclear polymorphism, mitosis, vascular proliferation, necrosis), immunohistochemical (Ki-67, p53 index) molecular-genetic factors (expression of VEGF, MGMT, IDH, CD34), amount of radiation and chemotherapy were analyzed.

RESULTS

In the entire group of patients, there was a direct correlation of life expectancy with MGMT status, IDH status, the number of courses of chemotherapy, the age of the patient, and the severity of the first surgical intervention.

CONCLUSION

Clinical features such as age at diagnosis and extent of surgical resection and amount of chemotherapy have predictive value in assessing their effect on life expectancy. Mutations in IDH and MGMT promoter methylation were the most important molecular factors determining long-term patient survival.

Prognostic Value of the Platelet-lymphocyte Ratio for Glioblastoma: A Systematic Review

BACKGROUND

Glioblastoma is the most common type of malignant glioma and is 1 of the most frequent primary tumors during adult life. The platelet-lymphocyte ratio (PLR) has been studied as an inflammatory marker associated with the prognosis of glioblastoma in previous studies. Considering the morbidity associated with this condition, it is important that there are other ways of assessing the prognosis that do not require invasive methods. Therefore, we performed this systematic review in order to determine the prognostic value of the PLR.

METHODS

We conducted an English language, literature-based search for papers published from 2012 to 2022, using the PubMed, Cochrane, Biblioteca Virtual em Saúde and Biomed Central Journal. We use the Preferred Reporting Items for Systematic Reviews and Meta-analyses recommendations. Titles and abstracts were evaluated independently by 2 authors, after which articles were selected for final analysis based on application of inclusion criteria (patients diagnosed with glioblastoma; address the use of PLR as a prognostic factor; hazard ratio; adults; clinical trials and observational studies) and exclusion criteria (inclusion of pediatric or animals, case reports, letters, conference abstracts, meta-analysis, and nonclinical studies or did not include hazard ratio) during full text screen. Each included article was then assessed for quality using Newcastle-Ottawa scale and relevant variables were extracted for synthesis.

RESULTS

Of 127 results, 11 articles were included for final analysis. There were 7 studies from China, 1 from Italy, 1 from Portugal, 1 from Turkey, and 1 from India. The years of publications were between 2015 and 2022. All the studies used PLR from the preoperative blood sample. Among the studies that analyzed the relationship between PLR and overall survival, 7 found a predictive relationship, 3 found no association, and 1 found an association between PLR and progression free survival in patients with glioblastoma.

CONCLUSIONS

Studies have shown that PLR can be a useful marker to aid in the prognosis of glioblastoma. Due to the ease of obtaining, rapid analysis and low cost, the PLR can be particularly beneficial in health centers with limited financial resources.

Non-coding RNAs and glioma: Focus on cancer stem cells

Glioblastoma and gliomas can have a wide range of histopathologic subtypes. These heterogeneous histologic phenotypes originate from tumor cells with the distinct functions of tumorigenesis and self-renewal, called glioma stem cells (GSCs). GSCs are characterized based on multi-layered epigenetic mechanisms, which control the expression of many genes. This epigenetic regulatory mechanism is often based on functional non-coding RNAs (ncRNAs). ncRNAs have become increasingly important in the pathogenesis of human cancer and work as oncogenes or tumor suppressors to regulate carcinogenesis and progression. These RNAs by being involved in chromatin remodeling and modification, transcriptional regulation, and alternative splicing of pre-mRNA, as well as mRNA stability and protein translation, play a key role in tumor development and progression. Numerous studies have been performed to try to understand the dysregulation pattern of these ncRNAs in tumors and cancer stem cells (CSCs), which show robust differentiation and self-regeneration capacity. This review provides recent findings on the role of ncRNAs in glioma development and progression, particularly their effects on CSCs, thus accelerating the clinical implementation of ncRNAs as promising tumor biomarkers and therapeutic targets.

MicroRNA-640 Inhibition Enhances the Chemosensitivity of Human Glioblastoma Cells to Temozolomide by Targeting Bcl2 Modifying Factor

Glioblastoma (GBM) is the most malignant and challenging type of astrocytoma and also notoriously acknowledged as the most common primary brain tumor globally. Currently, chemotherapy is the most master therapy for tumor and is essential in clinical treatment for GBM. Nevertheless, the characterization of chemotherapy resistance seriously hinders clinical chemotherapy treatment. Accordingly, there are imperious demands for the exploitation of novel chemosensitizer to promote the efficacy of chemotherapy. Our current study was conducted to probe into the potential impacts of microRNA (miR)-640 on the chemosensitivity in GBM and the associated underlying mechanism. Initially, TargetScan software was utilized to predict the targeted genes of miR-640, and the target relationship between miR-640 and Bcl-2-modifying factor (BMF) was validated by double luciferase report assay. Additionally, to explore the role of miR-640/BMF in U251 cells, miR-640 inhibitor/BMF-siRNA was used. U251 cells were processed with 100 μM temozolomide (TMZ) and detected with CCK-8 kit. Eventually, RT-qPCR and Western blotting were used for evaluating Bcl-2, Bax mRNA, and protein expression level. Flow cytometry analysis was performed to measure cellular apoptosis. Initially, the results indicated that BMF was the target gene of miR-640. MiR-640 negatively regulated BMF expression in GBM cells. Besides, the findings revealed that miR-640 inhibition significantly inhibited U251 cell proliferation, promoted cell apoptosis, and increased the sensitivity of GBM cells to TMZ by targeting BMF. Moreover, BMF overexpression significantly suppressed U251 cell proliferation, induced cell apoptosis, and increased the sensitivity of GBM cells to TMZ. Inhibition of miR-640 expression enhances chemosensitivity of human GBM cells to TMZ by targeting BMF.

Construction of a novel microRNA-based signature for predicting the prognosis of glioma

Background and purpose: Glioma is a frequent primary brain tumor. MicroRNAs (miRNA) have been shown to potentially play a crucial part in tumor development. Based on miRNAs and clinical factors, a model was constructed to predict the glioma prognosis. Methods: The miRNA expression profiles of glioma come from The Cancer Genome Atlas (TCGA, training group) and Chinese Glioma Genome Atlas (CGGA, validation group). Regression analyses of Cox and Lasso were applied to identity miRNAs associated with glioma prognosis in the TCGA database. The miRNAs were combined with clinical factors to construct individualized prognostic prediction models, whose performance was validated in the CGGA database. The role of miRNA in glioma development was investigated by in vitro experiments.Results: We identified five key miRNAs associated with glioma prognosis and constructed a prediction model. The area under ROC curve for predicting 3-year survival of glioma patients in the TCGA and CGGA groups was 0.844 and 0.770, respectively. The nomogram constructed using the miRNA risk scores and clinical factors showed high accuracy of prediction in the TCGA group (C-index of 0.820) and the CGGA group (C-index of 0.722). The miR-196b-5p altered the migration, proliferation, invasion, and apoptosis of glioma cells by regulating target genes, according to in vitro experiments.Conclusions: A miRNA-based individualized prognostic prediction model was constructed for glioma and miR-196b-5p was identified as a potential biomarker of glioma development.

Establishment and Analysis of an Individualized Immune-Related Gene Signature for the Prognosis of Gastric Cancer

A growing number of studies have shown that immunity plays an important clinical role in the process of gastric cancer (GC). The purpose of this study was to explore the function of differentially expressed immune-related genes (DEIRGs) of GC, and construct a gene signature to predict the overall survival (OS) of patients. Gene expression profiles and clinical data of GC patients were downloaded from TCGA and GEO databases. Combined with immune-related genes (IRGs) downloaded from the ImmPort database, 357 DEIRGs in GC tissues and adjacent tissues were identified. Based on the analysis of Lasso and Cox in the training set, a prognostic risk scoring model consisting of 9 (RBP7, DES, CCR1, PNOC, SPP1, VIP, TNFRSF12A, TUBB3, PRKCG) DEIRGs was obtained. Functional analysis revealed that model genes may participate in the formation and development of tumor cells by affecting the function of cell gap junction intercellular communication (GJJC). According to the model score, the samples were divided into high-risk and low-risk groups. In multivariate Cox regression analysis, the risk score was an independent prognostic factor (HR = 1.674, 95% CI = 1.470–1.907, P < 0.001). Survival analysis showed that the OS of high-risk GC patients was significantly lower than that of low-risk GC patients (P < 0.001). The area under the receiver operating characteristic curve (ROC) of the model was greater than other clinical indicators when verified in various data sets, confirming that the prediction model has a reliable accuracy. In conclusion, this study has explored the biological functions of DEIRGs in GC and discovered novel gene targets for the treatment of GC. The constructed prognostic gene signature is helpful for clinicians to determine the prognosis of GC patients and formulate personalized treatment plans.

Survival Benefit of Supratotal Resection in a Long-term Survivor of IDH-wildtype Glioblastoma: A Case Report and Literature Review

Glioblastoma multiforme (GBM) is an aggressive cancer type, with fewer than 3–5% of patients surviving for more than 3 years. We describe a 48-year-old right-handed man who presented with generalized seizure attacks. Magnetic resonance imaging (MRI) revealed a heterogeneous gadolinium-enhancing lesion in the left inferior parietal lobule. The patient underwent awake surgery, and tumor resection included abnormalities on T2-weighted MRI, with subcortical mapping used to identify the deep functional boundaries. After supratotal resection, the tumor was diagnosed as GBM without isocitrate dehydrogenase (IDH) 1 and 2 mutations. At a follow-up evaluation, 9 years and 2 months after the surgery, the patient appeared healthy, and no relapse or recurrence was observed. We present the case of a long-term survivor of IDH-wildtype GBM. This case suggests that supratotal resection with intraoperative awake brain mapping can improve survival without impairing the patient’s neurological functions.

Development of a prognostic index and screening of prognosis related genes based on an immunogenomic landscape analysis of bladder cancer

BACKGROUND

Bladder cancer (BLCA) is one of the most common urinary tract malignant tumors. It is associated with poor outcomes, and its etiology and pathogenesis are not fully understood. There is great hope for immunotherapy in treating many malignant tumors; therefore, it is worthwhile to explore the use of immunotherapy for BLCA.

METHODS

Gene expression profiles and clinical information were obtained from The Cancer Genome Atlas (TCGA), and immune-related genes (IRGs) were downloaded from the Immunology Database and Analysis Portal. Differentially-expressed and survival-associated IRGs in patients with BLCA were identified using computational algorithms and Cox regression analysis. We also performed functional enrichment analysis. Based on IRGs, we employed multivariate Cox analysis to develop a new prognostic index.

RESULTS

We identified 261 IRGs that were differentially expressed between BLCA tissue and adjacent tissue, 30 of which were significantly associated with the overall survival (all P<0.01). According to multivariate Cox analysis, nine survival-related IRGs (MMP9, PDGFRA, AHNAK, OAS1, OLR1, RAC3, IGF1, PGF, and SH3BP2) were high-risk genes. We developed a prognostic index based on these IRGs and found it accurately predicted BLCA outcomes associated with the TNM stage. Intriguingly, the IRG-based prognostic index reflected infiltration of macrophages.

CONCLUSIONS

An independent IRG-based prognostic index provides a practical approach for assessing patients' immune status and prognosis with BLCA. This index independently predicted outcomes of BLCA.

LncRNA NEAT1 promotes malignant phenotypes and TMZ resistance in glioblastoma stem cells by regulating let-7g-5p/MAP3K1 axis

Glioblastoma multiforme (GBM) is one of the most malign brain tumors in adults. Temozolomide (TMZ) is an oral chemotherapy drug constituting the backbone of chemotherapy regimens utilized as first-line treatment of GBM. However, resistance to TMZ often leads to treatment failure. In the present study, we explored the expression and related mechanisms of nuclear enriched abundant transcript 1 (NEAT1) in glioma stem cells (GSCs). Quantitative real-time PCR (qRT-PCR) showed that NEAT1 was up-regulated in serum samples of GBM patients and GSCs isolated from U87, U251 cell lines. Functional experiments showed that NEAT1 knockdown restrained malignant behaviors of GSC, including proliferation, migration and invasion. Dual-luciferase assays identified let-7g-5p was a downstream target and negatively adjusted by NEAT1. Restoration of let-7g-5p impeded tumor progression by inhibiting proliferation, migration and invasion. Mitogen-activated protein kinase kinase kinase 1 (MAP3K1), as a direct target of let-7g-5p, was positively regulated by NEAT1 and involved to affect the regulation of NEAT1 on GSCs' behaviors. In conclusion, our results suggested that NEAT1 promoted GSCs progression via NEAT1/let-7g-5p/MAP3K1 axis, which provided a depth insight into TMZ resistance mechanism.

Prognostic Value of microRNA-221/2 and 17-92 Families in Primary Glioblastoma Patients Treated with Postoperative Radiotherapy

MicroRNAs (miRs) are non-coding master regulators of transcriptome that could act as tumor suppressors (TSs) or oncogenes (oncomiRs). We aimed to systematically investigate the relevance of miRs as prognostic biomarkers in primary glioblastoma multiforme (GBM) treated with postoperative radio(chemo)therapy (PORT). For hypothesis generation, tumor miR expression by Agilent 8x15K human microRNA microarrays and survival data from 482 GBM patients of The Cancer Genome Atlas (TCGA cohort) were analyzed using Cox-PH models. Expression of candidate miRs with prognostic relevance (miR-221/222; miR-17-5p, miR-18a, miR-19b) was validated by qRT-PCR using Taqman technology on an independent validation cohort of GBM patients (n = 109) treated at Heidelberg University Hospital (HD cohort). In TCGA, 50 miRs showed significant association with survival. Among the top ranked prognostic miRs were members of the two miR families miR-221/222 and miR-17-92. Loss of miR-221/222 was correlated with improved prognosis in both cohorts (TCGA, HD) and was an independent prognostic marker in a multivariate analysis considering demographic characteristics (age, sex, Karnofsky performance index (KPI)), molecular markers (O-6-methylguanine-DNA methyltransferase (MGMT) methylation, IDH mutation status) and PORT as co-variables. The prognostic value of miR-17-92 family members was ambiguous and in part contradictory by direct comparison of the two cohorts, thus warranting further validation in larger prospective trials.

Prognostic value of test(s) for O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation for predicting overall survival in people with glioblastoma treated with temozolomide

BACKGROUND

Glioblastoma is an aggressive form of brain cancer. Approximately five in 100 people with glioblastoma survive for five years past diagnosis. Glioblastomas that have a particular modification to their DNA (called methylation) in a particular region (the O6-methylguanine-DNA methyltransferase (MGMT) promoter) respond better to treatment with chemotherapy using a drug called temozolomide.

OBJECTIVES

To determine which method for assessing MGMT methylation status best predicts overall survival in people diagnosed with glioblastoma who are treated with temozolomide.

SEARCH METHODS

We searched MEDLINE, Embase, BIOSIS, Web of Science Conference Proceedings Citation Index to December 2018, and examined reference lists. For economic evaluation studies, we additionally searched NHS Economic Evaluation Database (EED) up to December 2014.

SELECTION CRITERIA

Eligible studies were longitudinal (cohort) studies of adults with diagnosed glioblastoma treated with temozolomide with/without radiotherapy/surgery. Studies had to have related MGMT status in tumour tissue (assessed by one or more method) with overall survival and presented results as hazard ratios or with sufficient information (e.g. Kaplan-Meier curves) for us to estimate hazard ratios. We focused mainly on studies comparing two or more methods, and listed brief details of articles that examined a single method of measuring MGMT promoter methylation. We also sought economic evaluations conducted alongside trials, modelling studies and cost analysis.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook all steps of the identification and data extraction process for multiple-method studies. We assessed risk of bias and applicability using our own modified and extended version of the QUality In Prognosis Studies (QUIPS) tool. We compared different techniques, exact promoter regions (5'-cytosine-phosphate-guanine-3' (CpG) sites) and thresholds for interpretation within studies by examining hazard ratios. We performed meta-analyses for comparisons of the three most commonly examined methods (immunohistochemistry (IHC), methylation-specific polymerase chain reaction (MSP) and pyrosequencing (PSQ)), with ratios of hazard ratios (RHR), using an imputed value of the correlation between results based on the same individuals.

MAIN RESULTS

We included 32 independent cohorts involving 3474 people that compared two or more methods. We found evidence that MSP (CpG sites 76 to 80 and 84 to 87) is more prognostic than IHC for MGMT protein at varying thresholds (RHR 1.31, 95% confidence interval (CI) 1.01 to 1.71). We also found evidence that PSQ is more prognostic than IHC for MGMT protein at various thresholds (RHR 1.36, 95% CI 1.01 to 1.84). The data suggest that PSQ (mainly at CpG sites 74 to 78, using various thresholds) is slightly more prognostic than MSP at sites 76 to 80 and 84 to 87 (RHR 1.14, 95% CI 0.87 to 1.48). Many variants of PSQ have been compared, although we did not see any strong and consistent messages from the results. Targeting multiple CpG sites is likely to be more prognostic than targeting just one. In addition, we identified and summarised 190 articles describing a single method for measuring MGMT promoter methylation status.

AUTHORS' CONCLUSIONS

PSQ and MSP appear more prognostic for overall survival than IHC. Strong evidence is not available to draw conclusions with confidence about the best CpG sites or thresholds for quantitative methods. MSP has been studied mainly for CpG sites 76 to 80 and 84 to 87 and PSQ at CpG sites ranging from 72 to 95. A threshold of 9% for CpG sites 74 to 78 performed better than higher thresholds of 28% or 29% in two of three good-quality studies making such comparisons.

Glioma-Derived miRNA-Containing Extracellular Vesicles Induce Angiogenesis by Reprogramming Brain Endothelial Cells

Glioblastoma (GBM) is characterized by aberrant vascularization and a complex tumor microenvironment. The failure of anti-angiogenic therapies suggests pathways of GBM neovascularization, possibly attributable to glioblastoma stem cells (GSCs) and their interplay with the tumor microenvironment. It has been established that GSC-derived extracellular vesicles (GSC-EVs) and their cargoes are proangiogenic in vitro. To further elucidate EV-mediated mechanisms of neovascularization in vitro, we perform RNA-seq and DNA methylation profiling of human brain endothelial cells exposed to GSC-EVs. To correlate these results to tumors in vivo, we perform histoepigenetic analysis of GBM molecular profiles in the TCGA collection. Remarkably, GSC-EVs and normal vascular growth factors stimulate highly distinct gene regulatory responses that converge on angiogenesis. The response to GSC-EVs shows a footprint of post-transcriptional gene silencing by EV-derived miRNAs. Our results provide insights into targetable angiogenesis pathways in GBM and miRNA candidates for liquid biopsy biomarkers.

Emerging role of miRNAs as liquid biopsy markers for prediction of glioblastoma multiforme prognosis

Serum miRNAs (miRs) have gained consideration as encouraging molecular markers for cancer diagnosis and prediction of prognosis. The authors aimed to identify the exact role of miR-17-5p, miR-125b, and miR-221 among glioblastoma multiforme (GBM) patients before and after standard treatment, and correlate their expression with survival pattern. The study included 25 GBM patients and 20 healthy controls. Serum miR-17-5p, miR-125b, and miR-221 expression were analyzed before and after treatment using quantitative real-time polymerase chain reaction (qPCR). The diagnostic efficacy for the tested miRs was evaluated using the receiver operating characteristic (ROC) curve, and the relation of miRs expression versus clinical criteria for GBM was assessed. Patients' survival patterns were examined versus miRs expression levels. A significant difference was reported between miRs expression among the enrolled individuals. Both miR-17-5p and miR-221 reported significant elevations in GBM patients who: are above 60 years old, underwent biopsy resection, have a non-frontal lesion, with tumor size above 5 cm, and with performance status equals 2 according to the Eastern Cooperative Oncology Group (ECOG) Performance Status. With regard to miR-125b, a significant difference was detected according to surgery strategy, primary lesion of the tumor, and ECOG status. MiRs levels were significantly decreased for GBM patients after treatment. Survival patterns demonstrated an increase in miR-17-5p, miR-125b, and miR-221 in GBM patients with worse progression-free survival and among those with worse overall survival. Detection of serum miR-17-5p, miR-125b, and miR-221 aids in the prediction of prognosis and response to treatment strategy for GBM patients.

Diagnostic, prognostic, and therapeutic significance of miR-139-5p in cancers

miRNAs are a group of non-coding RNAs that have regulatory functions in post-transcriptional gene expression. These molecules play a fundamental role in cellular processes, for instance cell proliferation, apoptosis, migration, and invasion. Scientific investigations have previously established that miRNAs can either promote or suppress tumor development by mediating different signaling pathways. miR-139-5p, located on chromosome 11q13.4, has been examined extensively in cancers. Studies have demonstrated that miR-139-5p might be an attractive cancer biomarker. Herein, we will review how miR-139-5p acts in cancer diagnosis, prognosis, and therapy, as well as elucidating its major target genes and associated signaling pathways.

miR‑296‑3p promotes the proliferation of glioblastoma cells by targeting ICAT

MicroRNAs (miRNA/miRs) serve an important function in the regulation of gene expression, and have been indicated to mediate a number of cellular biological processes, including cell proliferation, the cell cycle, cell apoptosis and cell differentiation. The altered expression of miRNAs has been revealed to result in a variety of human diseases, including glioblastoma multiforme (GBM). The present study indicated an increase in miR‑296‑3p in glioma tumor types compared with normal brain, particularly in the samples from patients with high grade GBM. Antagonizing miR‑296‑3p was demonstrated to induce cell growth arrest and cell cycle redistribution in U251 cells. The miR‑296‑3p antagonist altered the expression of a number of key genes that are involved in cell cycle control, including cyclin D1 and p21. Additionally, the decrease of miR‑296‑3p increased inhibitor of β‑catenin and T cell factor (ICAT) expression, and increased miR‑296‑3p‑inhibited ICAT expression in U251 cells. Bioinformatics analysis indicated that ICAT is a target gene of miR‑296‑3p, which was further validated using a dual‑luciferase reporter assay. Through the regulation of ICAT, the miR‑296‑3p antagonist decreased β‑catenin protein expression and increased the expression of its target genes. Silencing ICAT was indicated to reverse the miR‑296‑3p downregulation‑induced inactivation of Wnt signaling and cell growth arrest in glioma cells. The present study also indicated a negative correlation between ICAT mRNA levels and miR‑296‑3p levels in glioma tumor types. In conclusion, the present study identified an oncogenic function of miR‑296‑3p in glioblastoma via the direct regulation of ICAT.

Identification of a novel DNA repair-related prognostic signature predicting survival of patients with hepatocellular carcinoma

Purpose

Hepatocellular carcinoma (HCC) is the sixth most lethal neoplasm worldwide. Traditional biomarkers often exploit the relationship between a certain gene and cancer progression, but they cannot predict patient survival or prognosis accurately. We aim to construct a new DNA repair-related gene signature that combines several genes to improve prognosis prediction in HCC.

Methods

We selected an HCC mRNA sequencing (mRNA-seq) dataset (n=365) from The Cancer Genome Atlas (TCGA), and gene set enrichment analysis (GSEA) was used to explore bioinformatics information and further screen genes. We then built a gene signature based on the Cox proportional hazards regression model.

Results

GSEA revealed that the hallmark DNA repair gene set was significantly upregulated in the tumor phenotype. A set of seven genes, namely, ADA, FEN1, POLR2G, SAC3D1, SEC61A1, SF3A3, and UPF3B, were significantly a ssociated with overall survival (OS) and used to form a gene signature. The signature risk score was calculated and used to divide patients into high‐ and low‐risk groups. The high-risk group showed worse prognosis (log-rank test p<0.0001). Univariate and multivariate Cox regression analysis showed that the prognostic performance of this risk score signature was robust in different subgroups based on clinicopathological features, with p-values <0.05 (HR=2.38, 95% CI (confidence interval) =1.355–4.184), indicating that it can serve as an independent prognostic indicator.

Conclusion

We developed and identified a seven‐gene signature related to the DNA repair process that can predict survival in HCC. It can be used as an effective classification tool and to guide clinical treatment.

Analysis of microarray data for identification of key microRNA signatures in glioblastoma multiforme

Glioblastoma multiforme (GBM) is one of the most malignant types of glioma known for its reduced survival rate and rapid relapse. Previous studies have shown that the expression patterns of different microRNAs (miRNA/miR) play a crucial role in the development and progression of GBM. In order to identify potential miRNA signatures of GBM for prognostic and therapeutic purposes, we downloaded and analyzed two expression data sets from Gene Expression Omnibus profiling miRNA patterns of GBM compared with normal brain tissues. Validated targets of the deregulated miRNAs were identified using MirTarBase, and were mapped to Search Tool for the Retrieval of Interacting Genes/Proteins, Database for Annotation, Visualization and Integrated Discovery and Kyoto Encyclopedia of Genes and Genomes databases in order to construct interaction networks and identify enriched pathways of target genes. A total of 6 miRNAs were found to be deregulated in both expression datasets studied. Pathway analysis demonstrated that most of the target genes were enriched in signaling cascades connected to cancer development, such as ‘Pathways in cancer’, ‘Focal adhesion’ and ‘PI3K-Akt signaling pathway’. Of the five target genes that were enriched in the glioblastoma pathway, in the WikiPathway database, both HRas proto-oncogene, GTPase and MET proto-oncogene, receptor tyrosine kinase target genes of hsa-miR-139-5p, were found to be significantly associated with patient survival. The present study may thus form the basis for further exploration of hsa-miR-139-5p, not only as a therapeutic agent, but also as a diagnostic biomarker for GBM as well as a predictive marker for patient survival.

Genetic secrets of long-term glioblastoma survivors

Glioblastomas are the most aggressive and lethal primary astrocytic tumors of the central nervous system. They account for 60% to 70% of all gliomas and the majority are diagnosed in Caucasian male patients at advanced age. Genetic analyses of glioblastoma show a great intra- and inter-tumor heterogeneity, which opens up a debate about its cellular origin. Different types of brain cells, including astrocytes, neural stem cells, oligodendrocyte precursor cells and glioblastoma stem cells are proposed to have a role in tumor initiation and spreading; however, data is still inconclusive. Due to short life expectancy, long-term glioblastoma survivors are defined as patients who live longer than two years post-diagnosis. Extreme survivors, living 10 years or more after diagnosis, comprise less than 1% of all patients. Molecular testing indicates genetic differences between short- and long-term survivors with glioblastoma. The most informative are IDH1/2 gene mutations and MGMT promoter methylation, which are associated with a better response to standard clinical care. Moreover, a decreased expression of the CHI3L1, FBLN4, EMP3, IGFBP2, IGFBP3, LGALS3, MAOB, PDPN, SERPING1 and TIMP1 genes has been associated with prolonged survival. In addition, emerging evidence suggests the role of different microRNAs in predicting patient survival. Other factors that may affect the survival of glioblastoma patients include clinical/demographic characteristics such as seizures at presentation, age at diagnosis, and the extent of surgical resection. Because of the small number of long-term survivors with glioblastoma, comparative studies on genetic differences between short- and long-term survivors are challenging. To improve patient management and clinical outcomes, a thorough "omics" approach is necessary for identifying differences between short- and long-term survivors with glioblastoma.

Oligonucleotide Therapeutics as a New Class of Drugs for Malignant Brain Tumors: Targeting mRNAs, Regulatory RNAs, Mutations, Combinations, and Beyond

Malignant brain tumors are rapidly progressive and often fatal owing to resistance to therapies and based on their complex biology, heterogeneity, and isolation from systemic circulation. Glioblastoma is the most common and most aggressive primary brain tumor, has high mortality, and affects both children and adults. Despite significant advances in understanding the pathology, multiple clinical trials employing various treatment strategies have failed. With much expanded knowledge of the GBM genome, epigenome, and transcriptome, the field of neuro-oncology is getting closer to achieve breakthrough-targeted molecular therapies. Current developments of oligonucleotide chemistries for CNS applications make this new class of drugs very attractive for targeting molecular pathways dysregulated in brain tumors and are anticipated to vastly expand the spectrum of currently targetable molecules. In this chapter, we will overview the molecular landscape of malignant gliomas and explore the most prominent molecular targets (mRNAs, miRNAs, lncRNAs, and genomic mutations) that provide opportunities for the development of oligonucleotide therapeutics for this class of neurologic diseases. Because malignant brain tumors focally disrupt the blood-brain barrier, this class of diseases might be also more susceptible to systemic treatments with oligonucleotides than other neurologic disorders and, thus, present an entry point for the oligonucleotide therapeutics to the CNS. Nevertheless, delivery of oligonucleotides remains a crucial part of the treatment strategy. Finally, synthetic gRNAs guiding CRISPR-Cas9 editing technologies have a tremendous potential to further expand the applications of oligonucleotide therapeutics and take them beyond RNA targeting.

MicroRNA in Brain pathology: Neurodegeneration the Other Side of the Brain Cancer

The mammalian brain is made up of billions of neurons and supporting cells (glial cells), intricately connected. Molecular perturbations often lead to neurodegeneration by progressive loss of structure and malfunction of neurons, including their death. On the other side, a combination of genetic and cellular factors in glial cells, and less frequently in neurons, drive oncogenic transformation. In both situations, microenvironmental niches influence the progression of diseases and therapeutic responses. Dynamic changes that occur in cellular transcriptomes during the progression of developmental lineages and pathogenesis are controlled through a variety of regulatory networks. These include epigenetic modifications, signaling pathways, and transcriptional and post-transcriptional mechanisms. One prominent component of the latter is small non-coding RNAs, including microRNAs, that control the vast majority of these networks including genes regulating neural stemness, differentiation, apoptosis, projection fates, migration and many others. These cellular processes are also profoundly dependent on the microenvironment, stemness niche, hypoxic microenvironment, and interactions with associated cells including endothelial and immune cells. Significantly, the brain of all other mammalian organs expresses the highest number of microRNAs, with an additional gain in expression in the early stage of neurodegeneration and loss in expression in oncogenesis. However, a mechanistic explanation of the concept of an apparent inverse correlation between the odds of cancer and neurodegenerative diseases is only weakly developed. In this review, we thus will discuss widespread de-regulation of microRNAome observed in these two major groups of brain pathologies. The deciphering of these intricacies is of importance, as therapeutic restoration of pre-pathological microRNA landscape in neurodegeneration must not lead to oncogenesis and vice versa. We thus focus on microRNAs engaged in cellular processes that are inversely regulated in these diseases. We also aim to define the difference in microRNA networks between pro-survival and pro-apoptotic signaling in the brain.

Selection of three miRNA signatures with prognostic value in non-M3 acute myeloid leukemia

BACKGROUND

MiRNAs that are potential biomarkers for predicting prognosis for acute myeloid leukemia (AML) have been identified. However, comprehensive analyses investigating the association between miRNA expression profiles and AML survival remain relatively deficient.

METHOD

In the present study, we performed multivariate Cox's analysis and principal component analysis (PCA) using data from The Cancer Genome Atlas (TCGA) to identify potential molecular signatures for predicting non-M3 AML prognosis.

RESULT

We found that patients who were still living were significantly younger at diagnosis than those who had died (P = 0.001). In addition, there was a marked difference in living status among different risk category groups (P = 0.022). A multivariate Cox model suggested that three miRNAs were potential biomarkers of non-M3 AML prognosis, including miR-181a-2, miR-25 and miR-362. Subsequently, PCA analyses were conducted to comprehensively represent the expression levels of these three miRNAs in each patient with a PCA value. According to the log-rank test, AML outcome for patients with lower PCA values was significantly different from those with higher PCA values (P < 0.001). Further bioinformatic analysis revealed the biological functions of the selected miRNAs.

CONCLUSION

We conducted a comprehensive analysis of TCGA non-M3 AML data, identifying three miRNAs that are significantly correlated with AML survival. PCA values for the identified miRNAs are valuable for predicting AML prognosis.

Downregulation of microRNA-374a predicts poor prognosis in human glioma

Certain microRNAs (miRNAs/miRs) may be used as prognostic biomarkers in various types of cancer. The purpose of the present study was to identify miRNAs that were abnormally expressed in glioma of different grades, and to evaluate their clinical implications in patients with glioma. The differentially expressed miRNAs were evaluated from the expression profiles of six glioma tissues (three low-grade and three high-grade gliomas) determined using a microarray platform. Reverse transcription-quantitative polymerase chain reaction analysis was used to further verify the aberrant expression of the candidate miRNA in a set of 42 patients and 5 healthy controls. The miRNA target genes were predicted and the protein-protein interaction network was generated; furthermore, functional enrichment analysis of the target genes in Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways was performed. Kaplan-Meier curves and Log-rank analysis, as well as multivariate Cox regression analysis were performed to assess the association of the candidate miRNA with patient survival. A total of 15 differentially expressed miRNAs, including 13 downregulated and 2 upregulated miRNAs, were identified by comparison of low-grade and high-grade glioma tissues. The miR-374a expression of high-grade gliomas was significantly lower than that of low-grade gliomas (fold change, -4.43; P=0.027). The expression levels of miR-374a gradually decreased with the increase of the pathological grade of glioma. Pearson's Chi-square test was used to determine the association of miR-374a expression with several clinicopathological factors. Furthermore, low expression of miR-374a was determined to be an independent prognostic marker and that it was significantly associated with overall survival (P=0.0213). GO and KEGG pathway analysis revealed that the target genes of miR-374a may be involved in the regulation of the RNA polymerase II promoter and mTOR signaling pathway. The four hub genes (CCND1, SP1, CDK4, CDK6) were also identified by PPI network analysis. In conclusion, the present study indicated that miR-374a may be used as a promising prognostic biomarker for the screening of high-risk populations and for the assessment of the prognosis of patients with glioma.

Aberrant miRNAs Regulate the Biological Hallmarks of Glioblastoma

GBM is the highest incidence in primary intracranial malignancy, and it remains poor prognosis even though the patient is gave standard treatment. Despite decades of intense research, the complex biology of GBM remains elusive. In view of eight hallmarks of cancer which were proposed in 2011, studies related to the eight biological capabilities in GBM have made great progress. From these studies, it can be inferred that miRs, as a mode of post-transcriptional regulation, are involved in regulating these malignant biological hallmarks of GBM. Herein, we discuss state-of-the-art research on how aberrant miRs modulate the eight hallmarks of GBM. The upregulation of 'oncomiRs' or the genetic loss of tumor suppressor miRs is associated with these eight biological capabilities acquired during GBM formation. Furthermore, we also discuss the applicable clinical potential of these research results. MiRs may aid in the diagnosis and prognosis of GBM. Moreover, miRs are also therapeutic targets of GBM. These studies will develop and improve precision medicine for GBM in the future.