Deregulated MicroRNA Signature Following Glioblastoma Irradiation

MicroRNAs targeted mTOR as therapeutic agents to improve radiotherapy outcome

MicroRNAs (miRNAs) are small RNA molecules that regulate genes and are involved in various biological processes, including cancer development. Researchers have been exploring the potential of miRNAs as therapeutic agents in cancer treatment. Specifically, targeting the mammalian target of the rapamycin (mTOR) pathway with miRNAs has shown promise in improving the effectiveness of radiotherapy (RT), a common cancer treatment. This review provides an overview of the current understanding of miRNAs targeting mTOR as therapeutic agents to enhance RT outcomes in cancer patients. It emphasizes the importance of understanding the specific miRNAs that target mTOR and their impact on radiosensitivity for personalized cancer treatment approaches. The review also discusses the role of mTOR in cell homeostasis, cell proliferation, and immune response, as well as its association with oncogenesis. It highlights the different ways in which miRNAs can potentially affect the mTOR pathway and their implications in immune-related diseases. Preclinical findings suggest that combining mTOR modulators with RT can inhibit tumor growth through anti-angiogenic and anti-vascular effects, but further research and clinical trials are needed to validate the efficacy and safety of using miRNAs targeting mTOR as therapeutic agents in combination with RT. Overall, this review provides a comprehensive understanding of the potential of miRNAs targeting mTOR to enhance RT efficacy in cancer treatment and emphasizes the need for further research to translate these findings into improved clinical outcomes.

miRNAs and related genetic biomarkers according to the WHO glioma classification: From diagnosis to future therapeutic targets

In the 2021 WHO classification of Tumors of the Central Nervous System, additional molecular characteristics have been included, defining the following adult-type diffuse glioma entities: Astrocytoma IDH-mutant, Oligodendroglioma IDH-mutant and 1p/19q-codeleted, and Glioblastoma IDH-wildtype. Despite advances in genetic analysis, precision oncology, and targeted therapy, malignant adult-type diffuse gliomas remain "hard-to-treat tumors", indicating an urgent need for better diagnostic and therapeutic strategies. In the last decades, miRNA analysis has been a hotspot for researching and developing diagnostic, prognostic, and predictive biomarkers for various disorders, including brain cancer. Scientific interest has recently been directed towards therapeutic applications of miRNAs, with encouraging results. Databases such as NCBI, PubMed, and Medline were searched for a selection of articles reporting the relationship between deregulated miRNAs and genetic aberrations used in the latest WHO CNS classification. The current review discussed the recommended molecular biomarkers and genetic aberrations based on the 2021 WHO classification in adult-type diffuse gliomas, along with associated deregulated miRNAs. Additionally, the study highlights miRNA-based treatment advancements in adults with gliomas.

MicroRNA as a potential diagnostic and prognostic biomarker in brain gliomas: a systematic review and meta-analysis

Introduction

Brain neoplasms and central nervous system (CNS) disorders, particularly gliomas, have shown a notable increase in incidence over the last three decades, posing significant diagnostic and therapeutic challenges. MicroRNAs (miRNAs) have emerged as promising biomarkers due to their regulatory role in gene expression, offering potential enhancements in glioma diagnosis and prognosis.

Methods

This systematic review and meta-analysis, adhering to PRISMA guidelines, included 25 studies for diagnostic accuracy and 99 for prognostic analysis, published until August 27th, 2023. Studies were identified through comprehensive searches of PubMed, Web of Science, and Scopus databases. Inclusion criteria encompassed peer-reviewed original research providing sensitivity, specificity, and area under the curve (AUC) for miRNAs in glioma diagnosis, as well as survival outcomes with hazard ratios (HRs) or mean survival.

Results and discussion

Meta-analysis demonstrated miRNAs' high diagnostic accuracy, with a pooled sensitivity of 0.821 (95% CI: 0.781-0.855) and specificity of 0.831 (95% CI: 0.792-0.865), yielding an AUC of 0.893. Subgroup analysis by specimen type revealed consistent accuracy across blood, cerebrospinal fluid (CSF), and tissue samples. Our results also showed miRNAs can be potential prognostic biomarkers. miRNAs showed significant associations with overall survival (OS) (pooled HR: 2.0221; 95% CI: 1.8497-2.2105), progression-free survival (PFS) (pooled HR: 2.4248; 95% CI: 1.8888-3.1128), and disease-free survival (DFS) (pooled HR: 1.8973; 95% CI: 1.1637-3.0933) in tissue specimens. These findings underscore miRNAs' potential as valuable biomarkers for improving glioma diagnosis and prognosis, offering insights for enhancing clinical decision-making and patient outcomes.

miRNAs role in glioblastoma pathogenesis and targeted therapy: Signaling pathways interplay

High mortality and morbidity rates and variable clinical behavior are hallmarks of glioblastoma (GBM), the most common and aggressive primary malignant brain tumor. Patients with GBM often have a dismal outlook, even after undergoing surgery, postoperative radiation, and chemotherapy, which has fueled the search for specific targets to provide new insights into the development of contemporary therapies. The ability of microRNAs (miRNAs/miRs) to posttranscriptionally regulate the expression of various genes and silence many target genes involved in cell proliferation, cell cycle, apoptosis, invasion, angiogenesis, stem cell behavior and chemo- and radiotherapy resistance makes them promising candidates as prognostic biomarkers and therapeutic targets or factors to advance GBM therapeutics. Hence, this review is like a crash course in GBM and how miRNAs related to GBM. Here, we will outline the miRNAs whose role in the development of GBM has been established by recent in vitro or in vivo research. Moreover, we will provide a summary of the state of knowledge regarding oncomiRs and tumor suppressor (TS) miRNAs in relation to GBM with an emphasis on their potential applications as prognostic biomarkers and therapeutic targets.

Analysis of MIR27A (rs11671784) Variant Association with Systemic Lupus Erythematous

Multiple microRNAs (miRs) are associated with systemic autoimmune disease susceptibility/phenotype, including systemic lupus erythematosus (SLE). With this work, we aimed to unravel the association of the miR-27a gene (MIR27A) rs11671784G/A variant with SLE risk/severity. One-hundred sixty-three adult patients with SLE and matched controls were included. A TaqMan allelic discrimination assay was applied for MIR27A genotyping. Logistic regression models were run to test the association with SLE susceptibility/risk. Genotyping of 326 participants revealed that the heterozygote form was the most common genotype among the study cohort, accounting for 72% of the population (n = 234), while A/A and G/G represented 15% (n = 49) and 13% (n = 43), respectively. Similarly, the most prevalent genotype among cases was the A/G genotype, which was present in approximately 93.3% of cases (n = 152). In contrast, only eight and three patients had A/A and G/G genotypes, respectively. The MIR27A rs11671784 variant conferred protection against the development of SLE in several genetic models, including heterozygous (G/A vs. A/A; OR = 0.10, 95% CI = 0.05–0.23), dominant (G/A + G/G vs. AA; OR = 0.15, 95% CI = 0.07–0.34), and overdominant (G/A vs. A/A + G/G; OR = 0.07, 95% CI = 0.04–0.14) models. However, the G/G genotype was associated with increased SLE risk in the recessive model (G/G vs. A/A+ G/G; OR = 17.34, 95% CI = 5.24–57.38). Furthermore, the variant showed significant associations with musculoskeletal and mucocutaneous manifestations in the patient cohort (p = 0.035 and 0.009, respectively) and platelet and white blood cell counts (p = 0.034 and 0.049, respectively). In conclusion, the MIR27A rs11671784 variant showed a potentially significant association with SLE susceptibility/risk in the studied population. Larger-scale studies on multiethnic populations are recommended to verify the results.

microRNAs (miRNAs) in Glioblastoma Multiforme (GBM)-Recent Literature Review

Glioblastoma multiforme (GBM) is the most common, malignant, poorly promising primary brain tumor. GBM is characterized by an infiltrating growth nature, abundant vascularization, and a rapid and aggressive clinical course. For many years, the standard treatment of gliomas has invariably been surgical treatment supported by radio- and chemotherapy. Due to the location and significant resistance of gliomas to conventional therapies, the prognosis of glioblastoma patients is very poor and the cure rate is low. The search for new therapy targets and effective therapeutic tools for cancer treatment is a current challenge for medicine and science. microRNAs (miRNAs) play a key role in many cellular processes, such as growth, differentiation, cell division, apoptosis, and cell signaling. Their discovery was a breakthrough in the diagnosis and prognosis of many diseases. Understanding the structure of miRNAs may contribute to the understanding of the mechanisms of cellular regulation dependent on miRNA and the pathogenesis of diseases underlying these short non-coding RNAs, including glial brain tumors. This paper provides a detailed review of the latest reports on the relationship between changes in the expression of individual microRNAs and the formation and development of gliomas. The use of miRNAs in the treatment of this cancer is also discussed.

Recent insights into the microRNA-dependent modulation of gliomas from pathogenesis to diagnosis and treatment

Gliomas are the most lethal primary brain tumors in adults. These highly invasive tumors have poor 5-year survival for patients. Gliomas are principally characterized by rapid diffusion as well as high levels of cellular heterogeneity. However, to date, the exact pathogenic mechanisms, contributing to gliomas remain ambiguous. MicroRNAs (miRNAs), as small noncoding RNAs of about 20 nucleotides in length, are known as chief modulators of different biological processes at both transcriptional and posttranscriptional levels. More recently, it has been revealed that these noncoding RNA molecules have essential roles in tumorigenesis and progression of multiple cancers, including gliomas. Interestingly, miRNAs are able to modulate diverse cancer-related processes such as cell proliferation and apoptosis, invasion and migration, differentiation and stemness, angiogenesis, and drug resistance; thus, impaired miRNAs may result in deterioration of gliomas. Additionally, miRNAs can be secreted into cerebrospinal fluid (CSF), as well as the bloodstream, and transported between normal and tumor cells freely or by exosomes, converting them into potential diagnostic and/or prognostic biomarkers for gliomas. They would also be great therapeutic agents, especially if they could cross the blood–brain barrier (BBB). Accordingly, in the current review, the contribution of miRNAs to glioma pathogenesis is first discussed, then their glioma-related diagnostic/prognostic and therapeutic potential is highlighted briefly.

Molecular and Circulating Biomarkers in Patients with Glioblastoma

Glioblastoma is the most aggressive malignant tumor of the central nervous system with a low survival rate. The difficulty of obtaining this tumor material represents a major limitation, making the real-time monitoring of tumor progression difficult, especially in the events of recurrence or resistance to treatment. The identification of characteristic biomarkers is indispensable for an accurate diagnosis, the rigorous follow-up of patients, and the development of new personalized treatments. Liquid biopsy, as a minimally invasive procedure, holds promise in this regard. The purpose of this paper is to summarize the current literature regarding the identification of molecular and circulating glioblastoma biomarkers and the importance of their integration as a valuable tool to improve patient care.

Association between microRNAs 10b/21/34a and acute toxicity in glioblastoma patients treated with radiotherapy and temozolomide

A personalized approach to chemoradiation is important in reducing its potential side effects and identifying a group of patients prone to toxicity. MicroRNAs have been shown to have a predictive potential for radiotoxicity. The goal of the study was to test if levels of miRNA in peripheral blood mononuclear cells of glioblastoma patients are associated with toxicity and to identify the peak time point for toxicity. MicroRNA-10b/21/34a levels were measured in 43 patients with and without toxicity, at baseline, at the 15th, and at the 30th fraction by Real-Time quantitative Polymerase Chain Reaction. MicroRNA-10b/21 levels increased with toxicity grade (p = 0.014; p = 0.013); miR-21/34a levels were significantly different between patients with and without toxicity at the 15th fraction (p = 0.030; p = 0.045), while miR-34a levels significantly changed during treatment (p < 0.001). All three miRNAs showed a significantly high positive correlation with one another. MiR-34a might be considered as a predictive factor for toxicity due to its changes during treatment, and differences between the groups with and without toxicity; miR-10b might be used to predict toxicity; miR-10b/21 might be used for predicting the grade of toxicity in GB patients.

Cell cultures in assessing radioresistance of glioblastomas

To date, no modern methods of treatment allow overcoming malignant potential of glial neoplasms and significant increase of survival. Analysis of glioblastoma radioresistance using cancer cell cultures is one of the perspective directions, as radiotherapy is standard and available treatment method for these neoplasms. This review summarizes current studies identifying many factors of radioresistance of glial tumors, such as hypoxia, microenvironment and metabolic features of tumor, stem cells, internal heterogeneity of tumor, microRNA, features of cell cycle, DNA damage and reparation. We obtained data on involvement of various molecular pathways in development of radioresistance such as MEK/ERK, c-MYC, PI3K/Akt, PTEN, Wnt, JAK/STAT, Notch, etc. Changes in activity of RAD51 APC, FZD1, LEF1, TCF4, WISP1, p53 and many others are determined in radioresistant cells. Further study of radioresistance pathways will allow development of specific target aptamers and inhibitors.

Regulatory interplay between microRNAs and WNT pathway in glioma

Glioma is one of the most common neoplasms of the central nervous system with a poor survival. Due to the obstacles in treating this disease, a part of recent studies mainly focuses on identifying the underlying molecular mechanisms that contribute to its malignancy. Altering microRNAs (miRNAs) expression pattern has been identified obviously in many cancers. Through regulating various targets and signaling pathways, miRNAs play a pivotal role in cancer progression. As one of the essential signaling pathways, WNT pathway is dysregulated in many cancers, and a growing body of evidence emphasis its dysregulation in glioma. Herein, we provide a comprehensive review of miRNAs involved in WNT pathway in glioma. Moreover, we show the interplay between miRNAs and WNT pathway in regulating different processes such as proliferation, invasion, migration, radio/chemotherapy resistance, and epithelial-mesenchymal-transition. Then, we introduce several drugs and treatments against glioma, which their effects are mediated through the interplay of WNT pathway and miRNAs.

An Integrated Bioinformatics Study of a Novel Niclosamide Derivative, NSC765689, a Potential GSK3β/β-Catenin/STAT3/CD44 Suppressor with Anti-Glioblastoma Properties

Despite management efforts with standard surgery, radiation, and chemotherapy, glioblastoma multiform (GBM) remains resistant to treatment, which leads to tumor recurrence due to glioma stem cells (GSCs) and therapy resistance. In this study, we used random computer-based prediction and target identification to assess activities of our newly synthesized niclosamide-derived compound, NSC765689, to target GBM oncogenic signaling. Using target prediction analyses, we identified glycogen synthase kinase 3β (GSK3β), β-Catenin, signal transducer and activator of transcription 3 (STAT3), and cluster of differentiation 44 (CD44) as potential druggable candidates of NSC765689. The above-mentioned signaling pathways were also predicted to be overexpressed in GBM tumor samples compared to adjacent normal samples. In addition, using bioinformatics tools, we also identified microRNA (miR)-135b as one of the most suppressed microRNAs in GBM samples, which was reported to be upregulated through inhibition of GSK3β, and subsequently suppresses GBM tumorigenic properties and stemness. We further performed in silico molecular docking of NSC765689 with GBM oncogenes; GSK3β, β-Catenin, and STAT3, and the stem cell marker, CD44, to predict protein-ligand interactions. The results indicated that NSC765689 exhibited stronger binding affinities compared to its predecessor, LCC09, which was recently published by our laboratory, and was proven to inhibit GBM stemness and resistance. Moreover, we used available US National Cancer Institute (NCI) 60 human tumor cell lines to screen in vitro anticancer effects, including the anti-proliferative and cytotoxic activities of NSC765689 against GBM cells, and 50% cell growth inhibition (GI₅₀) values ranged 0.23~5.13 μM. In summary, using computer-based predictions and target identification revealed that NSC765689 may be a potential pharmacological lead compound which can regulate GBM oncogene (GSK3β/β-Catenin/STAT3/CD44) signaling and upregulate the miR-135b tumor suppressor. Therefore, further in vitro and in vivo investigations will be performed to validate the efficacy of NSC765689 as a novel potential GBM therapeutic.

Extracellular Vesicles Loaded miRNAs as Potential Modulators Shared Between Glioblastoma, and Parkinson's and Alzheimer's Diseases

Glioblastoma (GBM) is the deadliest brain tumor. Its poor prognosis is due to cell heterogeneity, invasiveness, and high vascularization that impede an efficient therapeutic approach. In the past few years, several molecular links connecting GBM to neurodegenerative diseases (NDDs) were identified at preclinical and clinical level. In particular, giving the increasing critical role that epigenetic alterations play in both GBM and NDDs, we deeply analyzed the role of miRNAs, small non-coding RNAs acting epigenetic modulators in several key biological processes. Specific miRNAs, transported by extracellular vesicles (EVs), act as intercellular communication signals in both diseases. In this way, miRNA-loaded EVs modulate GBM tumorigenesis, as they spread oncogenic signaling within brain parenchyma, and control the aggregation of neurotoxic protein (Tau, Aβ-amyloid peptide, and α-synuclein) in NDDs. In this review, we highlight the most promising miRNAs linking GBM and NDDs playing a significant pathogenic role in both diseases.

Exosomes and exosomal microRNA in non-targeted radiation bystander and abscopal effects in the central nervous system

Localized cranial radiotherapy is a dominant treatment for brain cancers. After being subjected to radiation, the central nervous system (CNS) exhibits targeted effects as well as non-targeted radiation bystander effects (RIBE) and abscopal effects (RIAE). Radiation-induced targeted effects in the CNS include autophagy and various changes in tumor cells due to radiation sensitivity, which can be regulated by microRNAs. Non-targeted radiation effects are mainly induced by gap junctional communication between cells, exosomes containing microRNAs can be transduced by intracellular endocytosis to regulate RIBE and RIAE. In this review, we discuss the involvement of microRNAs in radiation-induced targeted effects, as well as exosomes and/or exosomal microRNAs in non-targeted radiation effects in the CNS. As a target pathway, we also discuss the Akt pathway which is regulated by microRNAs, exosomes, and/or exosomal microRNAs in radiation-induced targeted effects and RIBE in CNS tumor cells. As the CNS-derived exosomes can cross the blood-brain-barrier (BBB) into the bloodstream and be isolated from peripheral blood, exosomes and exosomal microRNAs can emerge as promising minimally invasive biomarkers and therapeutic targets for radiation-induced targeted and non-targeted effects in the CNS.

Radiation Effects on Brain Extracellular Matrix

Radiotherapy is an important therapeutic approach to treating malignant tumors of different localization, including brain cancer. Glioblastoma multiforme (GBM) represents the most aggressive brain tumor, which develops relapsed disease during the 1st year after the surgical removal of the primary node, in spite of active adjuvant radiochemotherapy. More and more evidence suggests that the treatment's success might be determined by the balance of expected antitumor effects of the treatment and its non-targeted side effects on the surrounding brain tissue. Radiation-induced damage of the GBM microenvironment might create tumor-susceptible niche facilitating proliferation and invasion of the residual glioma cells and the disease relapse. Understanding of molecular mechanisms of radiation-induced changes in brain ECM might help to reconsider and improve conventional anti-glioblastoma radiotherapy, taking into account the balance between its antitumor and ECM-destructing activities. Although little is currently known about the radiation-induced changes in brain ECM, this review summarizes current knowledge about irradiation effects onto the main components of brain ECM such as proteoglycans, glycosaminoglycans, glycoproteins, and the enzymes responsible for their modification and degradation.

Prognostic value of the miRNA-27a and PPAR/RXRα signaling axis in patients with thyroid carcinoma

The authors aimed to evaluate the prognostic value of miRNA-27a (miR-27a), peroxisome proliferator-activated receptor alpha/gamma (PPARα/γ) and retinoid X receptor alpha (RXRα) tissue expression in patients with thyroid carcinoma. The expression levels were quantified in 174 archived thyroid specimens using real-time quantitative PCR. Downregulation of miR-27a was associated with lymph node stage and multifocality. PPARα expression was associated with histopathological type, tumor size and lymph node invasion. Moreover, RXRα expression was lower in patients who underwent total/subtotal thyroidectomy or received radioactive iodine treatment. Patients with upregulated miR-27a and downregulated RXRα showed a higher frequency of advanced lymph node stage and relapse by cluster analysis. Both miR-27a and PPARα/RXRα showed association with different poor prognostic indices in thyroid cancer patients.

Radioresistance in Glioblastoma and the Development of Radiosensitizers

Ionizing radiation is a common and effective therapeutic option for the treatment of glioblastoma (GBM). Unfortunately, some GBMs are relatively radioresistant and patients have worse outcomes after radiation treatment. The mechanisms underlying intrinsic radioresistance in GBM has been rigorously investigated over the past several years, but the complex interaction of the cellular molecules and signaling pathways involved in radioresistance remains incompletely defined. A clinically effective radiosensitizer that overcomes radioresistance has yet to be identified. In this review, we discuss the current status of radiation treatment in GBM, including advances in imaging techniques that have facilitated more accurate diagnosis, and the identified mechanisms of GBM radioresistance. In addition, we provide a summary of the candidate GBM radiosensitizers being investigated, including an update of subjects enrolled in clinical trials. Overall, this review highlights the importance of understanding the mechanisms of GBM radioresistance to facilitate the development of effective radiosensitizers.

Emerging Roles and Potential Applications of Non-Coding RNAs in Glioblastoma

Non-coding RNAs (ncRNAs) comprise a diversity of RNA species, which do not have the potential to encode proteins. Non-coding RNAs include two classes of RNAs, namely: short regulatory ncRNAs and long non-coding RNAs (lncRNAs). The short regulatory RNAs, containing up to 200 nucleotides, include small RNAs, such as microRNAs (miRNA), short interfering RNAs (siRNAs), piwi-interacting RNAs (piRNAs), and small nucleolar RNAs (snoRNAs). The lncRNAs include long antisense RNAs and long intergenic RNAs (lincRNAs). Non-coding RNAs have been implicated as master regulators of several biological processes, their expression being strictly regulated under physiological conditions. In recent years, particularly in the last decade, substantial effort has been made to investigate the function of ncRNAs in several human diseases, including cancer. Glioblastoma is the most common and aggressive type of brain cancer in adults, with deregulated expression of small and long ncRNAs having been implicated in onset, progression, invasiveness, and recurrence of this tumor. The aim of this review is to guide the reader through important aspects of miRNA and lncRNA biology, focusing on the molecular mechanism associated with the progression of this highly malignant cancer type.

Peptidylarginine Deiminase Isozyme-Specific PAD2, PAD3 and PAD4 Inhibitors Differentially Modulate Extracellular Vesicle Signatures and Cell Invasion in Two Glioblastoma Multiforme Cell Lines

Glioblastoma multiforme (GBM) is an aggressive adult brain tumour with poor prognosis. Roles for peptidylarginine deiminases (PADs) in GBM have recently been highlighted. Here, two GBM cell lines were treated with PAD2, PAD3 and PAD4 isozyme-specific inhibitors. Effects were assessed on extracellular vesicle (EV) signatures, including EV-microRNA cargo (miR21, miR126 and miR210), and on changes in cellular protein expression relevant for mitochondrial housekeeping (prohibitin (PHB)) and cancer progression (stromal interaction molecule 1 (STIM-1) and moesin), as well as assessing cell invasion. Overall, GBM cell-line specific differences for the three PAD isozyme-specific inhibitors were observed on modulation of EV-signatures, PHB, STIM-1 and moesin protein levels, as well as on cell invasion. The PAD3 inhibitor was most effective in modulating EVs to anti-oncogenic signatures (reduced miR21 and miR210, and elevated miR126), to reduce cell invasion and to modulate protein expression of pro-GBM proteins in LN229 cells, while the PAD2 and PAD4 inhibitors were more effective in LN18 cells. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for deiminated proteins relating to cancer, metabolism and inflammation differed between the two GBM cell lines. Our findings highlight roles for the different PAD isozymes in the heterogeneity of GBM tumours and the potential for tailored PAD-isozyme specific treatment.