Against the Resilience of High-Grade Gliomas: The Immunotherapeutic Approach (Part I)

Pericytes Are Immunoregulatory Cells in Glioma Genesis and Progression

Vascular co-option is a consequence of the direct interaction between perivascular cells, known as pericytes (PCs), and glioblastoma multiforme (GBM) cells (GBMcs). This process is essential for inducing changes in the pericytes' anti-tumoral and immunoreactive phenotypes. Starting from the initial stages of carcinogenesis in GBM, PCs conditioned by GBMcs undergo proliferation, acquire a pro-tumoral and immunosuppressive phenotype by expressing and secreting immunosuppressive molecules, and significantly hinder the activation of T cells, thereby facilitating tumor growth. Inhibiting the pericyte (PC) conditioning mechanisms in the GBM tumor microenvironment (TME) results in immunological activation and tumor disappearance. This underscores the pivotal role of PCs as a key cell in the TME, responsible for tumor-induced immunosuppression and enabling GBM cells to evade the immune system. Other cells within the TME, such as tumor-associated macrophages (TAMs) and microglia, have also been identified as contributors to this immunomodulation. In this paper, we will review the role of these three cell types in the immunosuppressive properties of the TME. Our conclusion is that the cellular heterogeneity of immunocompetent cells within the TME may lead to the misinterpretation of cellular lineage identification due to different reactive stages and the identification of PCs as TAMs. Consequently, novel therapies could be developed to disrupt GBM-PC interactions and/or PC conditioning through vascular co-option, thereby exposing GBMcs to the immune system.

Hit discovery of novel 2-phenyl-substituted 4-amino-6,7-dihydro-5H-cyclopenta[d]pyrimidines as potential anti-glioblastoma therapeutics: Design, synthesis, biological evaluation, and computational screening

Glioblastoma multiforme (GBM) is a highly-aggressive, dreadful disease with poor prognosis and disappointing clinical success. There is an unmet medical need of molecularly-targeted therapeutics for GBM treatment. In the present work, a series of novel 2-phenyl-substituted 4-amino-6,7-dihydro-5H-cyclopenta[d]pyrimidines was designed, synthesized, purified, characterized, and evaluated for cytotoxicity against glioblastoma cell line U87-MG. The design process (virtual library enumeration around the core, physicochemical and molecular property prediction/calculation of the designs, filtering the undesirable ones, and the diversity analyses of the lead-like designs), was carefully curated so as to obtain a set of structurally-diverse, novel molecules (total 20), with a particular focus on the relatively unexplored core structure, 6,7-dihydro-5H-cyclopenta[d]pyrimidine. The preliminary screening was done using MTT assay at 10 and 100 μM concentrations of the title compounds F₁ -F₂₀ and positive control cisplatin, which yielded six hits (% inhibition at 10 μM: ~50%)-F₂ , F₃ , F₅ , F₇ , F₁₅ , and F₂₀ , which were taken up for IC₅₀ determination. The top hits F₂ and F₇ (IC₅₀  < 10 μM) were further used for computational studies such as target prediction, followed by their molecular docking in the binding sites of the top-3 predicted targets (epidermal growth factor receptor kinase domain, cyclin-dependent kinase 2 [CDK2]) /cyclin E, and anaplastic lymphoma kinase [ALK]). The docking pose analyses revealed interesting trends. The relatively planar core structure, presence of favorable hinge-binding substructures, basic groups, all added up, and culminated in appreciable cytotoxicity against GBM cell line.

Advances in NK cell therapy for brain tumors

Despite advances in treatment regimens that comprise surgery, chemotherapy, and radiation, outcome of many brain tumors remains dismal, more so when they recur. The proximity of brain tumors to delicate neural structures often precludes complete surgical resection. Toxicity and long-term side effects of systemic therapy remain a concern. Novel therapies are warranted. The field of NK cell-based cancer therapy has grown exponentially and currently constitutes a major area of immunotherapy innovation. This provides a new avenue for the treatment of cancerous lesions in the brain. In this review, we explore the mechanisms by which the brain tumor microenvironment suppresses NK cell mediated tumor control, and the methods being used to create NK cell products that subvert immune suppression. We discuss the pre-clinical studies evaluating NK cell-based immunotherapies that target several neuro-malignancies and highlight advances in molecular imaging of NK cells that allow monitoring of NK cell-based therapeutics. We review current and ongoing NK cell based clinical trials in neuro-oncology.

Brain AVMs-Related microRNAs: Machine Learning Algorithm for Expression Profiles of Target Genes

INTRODUCTION

microRNAs (miRNAs) are a class of non-coding RNAs playing a myriad of important roles in regulating gene expression. Of note, recent work demonstrated a critical role of miRNAs in the genesis and progression of brain arteriovenous malformations (bAVMs). Accordingly, here we examine miRNA signatures related to bAVMs and associated gene expression. In so doing we expound on the potential prognostic, diagnostic, and therapeutic significance of miRNAs in the clinical management of bAVMs.

METHODS

A PRISMA-based literature review was performed using PubMed/Medline database with the following search terms: "brain arteriovenous malformations", "cerebral arteriovenous malformations", "microRNA", and "miRNA". All preclinical and clinical studies written in English, regardless of date, were selected. For our bioinformatic analyses, miRWalk and miRTarBase machine learning algorithms were employed; the Kyoto Encyclopedia of Genes and Genomes (KEGG) database was quired for associated pathways/functions.

RESULTS

four studies were ultimately included in the final analyses. Sequencing data consistently revealed the decreased expression of miR-18a in bAVM-endothelial cells, resulting in increased levels of vascular endodermal growth factor (VEGF), Id-1, matrix metalloproteinase, and growth signals. Our analyses also suggest that the downregulation of miR-137 and miR-195* within vascular smooth muscle cells (VSMCs) may foster the activation of inflammation, aberrant angiogenesis, and phenotypic switching. In the peripheral blood, the overexpression of miR-7-5p, miR-629-5p, miR-199a-5p, miR-200b-3p, and let-7b-5p may contribute to endothelial proliferation and nidus development. The machine learning algorithms employed confirmed associations between miRNA-related target networks, vascular rearrangement, and bAVM progression.

CONCLUSION

miRNAs expression appears to be critical in managing bAVMs' post-transcriptional signals. Targets of microRNAs regulate canonical vascular proliferation and reshaping. Although additional scientific evidence is needed, the identification of bAVM miRNA signatures may facilitate the development of novel prognostic/diagnostic tools and molecular therapies for bAVMs.

Emerging immune-based technologies for high-grade gliomas

INTRODUCTION

The selection of a tailored and successful strategy for high-grade gliomas (HGGs) treatment is still a concern. The abundance of aberrant mutations within the heterogenic genetic landscape of glioblastoma strongly influences cell expansion, proliferation, and therapeutic resistance. Identification of immune evasion pathways opens the way to novel immune-based strategies. This review intends to explore the emerging immunotherapies for HGGs. The immunosuppressive mechanisms related to the tumor microenvironment and future perspectives to overcome glioma immunity barriers are also debated.

AREAS COVERED

An extensive literature review was performed on the PubMed/Medline and ClinicalTrials.gov databases. Only highly relevant articles in English and published in the last 20 years were selected. Data about immunotherapies coming from preclinical and clinical trials were summarized.

EXPERT OPINION

The overall level of evidence about the efficacy and safety of immunotherapies for HGGs is noteworthy. Monoclonal antibodies have been approved as second-line treatment, while peptide vaccines, viral gene strategies, and adoptive technologies proved to boost a vivid antitumor immunization. Malignant brain tumor-treating fields are ever-changing in the upcoming years. Constant refinements and development of new routes of drug administration will permit to design of novel immune-based treatment algorithms thus improving the overall survival.

Immune Landscape in PTEN-Related Glioma Microenvironment: A Bioinformatic Analysis

Introduction: PTEN gene mutations are frequently found in the genetic landscape of high-grade gliomas since they influence cell proliferation, proangiogenetic pathways, and antitumoral immune response. The present bioinformatics analysis explores the PTEN gene expression profile in HGGs as a prognostic factor for survival, especially focusing on the related immune microenvironment. The effects of PTEN mutation on the susceptibility to conventional chemotherapy were also investigated. Methods: Clinical and genetic data of GBMs and normal tissue samples were acquired from The Cancer Genome Atlas (TCGA)-GBM and Genotype-Tissue Expression (GTEx) online databases, respectively. The genetic differential expressions were analyzed in both groups via the one-way ANOVA test. Kaplan−Meier survival curves were applied to estimate the overall survival (OS) and disease-free survival (DFS). The Genomics of Drug Sensitivity in Cancer platform was chosen to assess the response of PTEN-mutated GBMs to temozolomide (TMZ). p < 0.05 was fixed as statistically significant. On Tumor Immune Estimation Resource and Gene Expression Profiling Interactive Analysis databases, the linkage between immune cell recruitment and PTEN status was assessed through Spearman’s correlation analysis. Results: PTEN was found mutated in 22.2% of the 617 TCGA-GBMs patients, with a higher log2-transcriptome per million reads compared to the GTEx group (255 samples). Survival curves revealed a worse OS and DFS, albeit not significant, for the high-PTEN profile GBMs. Spearman’s analysis of immune cells demonstrated a strong positive correlation between the PTEN status and infiltration of Treg (ρ = 0.179) and M2 macrophages (ρ = 0.303). The half-maximal inhibitor concentration of TMZ was proven to be lower for PTEN-mutated GBMs compared with PTEN wild-types. Conclusions: PTEN gene mutations prevail in GBMs and are strongly related to poor prognosis and least survival. The infiltrating immune lymphocytes Treg and M2 macrophages populate the glioma microenvironment and control the mechanisms of tumor progression, immune escape, and sensitivity to standard chemotherapy. Broader studies are required to confirm these findings and turn them into new therapeutic perspectives.

Therapeutic aspects of Sydenham's Chorea: an update

Sydenham’s Chorea (SC) is a hyperkinetic movement disorder associated with neuropsychiatric manifestations. It is believed to be caused by the autoimmune response following a group A beta-hemolytic streptococcal (GABHS) pharyngitis, and it is one of the major diagnostic criteria for Acute Rheumatic Fever (ARF) diagnosis. Despite having been known and studied for centuries, there are still no standardized therapies or official guidelines for SC treatment, so that it is necessarily left to physicians’ clinical experience. Antibiotic treatment, symptomatic therapies, and immunomodulatory treatment are the three pillars upon which SC patients’ management is currently based, but they still lack a solid scientific basis. The aim of this writing is precisely to review the state of the art of SC’s treatment, with an overview of the advances made in the last 5 years. However, since the therapeutic uncertainties are a mere reflection of the severe gap of knowledge that concerns SC’s pathogenesis and manifestations, the importance of high-quality research studies based on homogenized methodologies, instruments, and measured outcomes will also be stressed. (www.actabiomedica.it)

Against the Resilience of High-Grade Gliomas: Gene Therapies (Part II)

Introduction: High-grade gliomas (HGGs) still have a high rate of recurrence and lethality. Gene therapies were projected to overcome the therapeutic resilience of HGGs, due to the intrinsic genetic heterogenicity and immune evasion pathways. The present literature review strives to provide an updated overview of the novel gene therapies for HGGs treatment, highlighting evidence from clinical trials, molecular mechanisms, and future perspectives. Methods: An extensive literature review was conducted through PubMed/Medline and ClinicalTrials.gov databases, using the keywords “high-grade glioma,” “glioblastoma,” and “malignant brain tumor”, combined with “gene therapy,” “oncolytic viruses,” “suicide gene therapies,” “tumor suppressor genes,” “immunomodulatory genes,” and “gene target therapies”. Only articles in English and published in the last 15 years were chosen, further screened based on best relevance. Data were analyzed and described according to the PRISMA guidelines. Results: Viruses were the most vehicles employed for their feasibility and transduction efficiency. Apart from liposomes, other viral vehicles remain largely still experimental. Oncolytic viruses and suicide gene therapies proved great results in phase I, II preclinical, and clinical trials. Tumor suppressor, immunomodulatory, and target genes were widely tested, showing encouraging results especially for recurrent HGGs. Conclusions: Oncolytic virotherapy and suicide genes strategies are valuable second-line treatment options for relapsing HGGs. Immunomodulatory approaches, tumor suppressor, and target genes therapies may implement and upgrade standard chemoradiotherapy. Future research aims to improve safety profile and prolonging therapeutic effectiveness. Further clinical trials are needed to assess the efficacy of gene-based therapies.

Shedding the Light on the Natural History of Intracranial Aneurysms: An Updated Overview

The exact molecular pathways underlying the multifactorial natural history of intracranial aneurysms (IAs) are still largely unknown, to the point that their understanding represents an imperative challenge in neurovascular research. Wall shear stress (WSS) promotes the genesis of IAs through an endothelial dysfunction causing an inflammatory cascade, vessel remodeling, phenotypic switching of the smooth muscle cells, and myointimal hyperplasia. Aneurysm growth is supported by endothelial oxidative stress and inflammatory mediators, whereas low and high WSS determine the rupture in sidewall and endwall IAs, respectively. Angioarchitecture, age older than 60 years, female gender, hypertension, cigarette smoking, alcohol abuse, and hypercholesterolemia also contribute to growth and rupture. The improvements of aneurysm wall imaging techniques and the implementation of target therapies targeted against inflammatory cascade may contribute to significantly modify the natural history of IAs. This narrative review strives to summarize the recent advances in the comprehension of the mechanisms underlying the genesis, growth, and rupture of IAs.

Gene Polymorphisms Increasing the Risk of Intracranial Aneurysms: Interleukin-6 -174G>C and -572G>C (Part II)

Introduction The interleukin-6 (IL-6), a proinflammatory cytokine, supports the adaptive immune response and regulates inflammatory processes. The -174 G>C and -572 G>C promoter polymorphisms of the IL-6 gene take part in the pathogenesis of intracranial aneurysms (IAs) and influence the clinical presentation of subarachnoid hemorrhage. This meta-analysis purposes to evaluate whether and which IL-6 allelic variations are related to a risk of IAs formation. Methods A PRISMA-based literature search was performed on the PubMed/Medline and Web of Science databases. The keywords used were "interleukin-6," "IL-6," "polymorphism," "interleukin-6 genotype," combined with "intracranial aneurysms" and "subarachnoid hemorrhage." Only human case-control studies, with a study (IAs) and a control group, written in English, and published in the last 15 years were selected. A meta-analysis was performed, estimating odds ratios and 95% confidence intervals in fixed- or random-effects models, as applicable. Statistical analysis was conducted with RevMan 5.0 software. Results 9 studies were eligible. No associations were found between -174 G>C polymorphisms and IAs susceptibility. Notable results were reported by the analysis of -572G>C polymorphisms. -572GG/GC/CC genotypes were strongly related to IAs occurrence with a statistical significance of p=0.03, p=0.0009, and p=0.00001, respectively. Conclusion A higher incidence of -572G>C promoter polymorphisms were demonstrated in the IAs group, highlighting the pivotal role of inflammatory genes in the natural history of brain aneurysms. Additional studies are required considering the racial heterogenicity and the need to widen the population sample.

An Overview of The Role of Tumor Necrosis Factor-Alpha in Epileptogenesis and Its Terapeutic Implications

The complex association between neuroinflammation and seizures has been widely investigated in recent years. As mediators of inflammatory response, cytokines like tumor necrosis factor- a (TNF-a) are potential therapeutic targets for epileptic disorders. TNF-a is a pleiotropic cytokine with a controversial role in epileptogenesis, seemingly capable to both favor the genesis of seizures and elicit neuromodulatory responses. Anti-TNF agents are a group of monoclonal antibodies engineered to inhibit the response to this cytokine for antinflammatory purposes. The clinical experience of the use of these drugs in neurological conditions like multiple sclerosis showed controversial results. Evidence in favor of the employment of anti-TNF agents for the treatment of epilepsy are still limited to certain forms of disorders, notably Rasmussen encephalitis, and in carefully selected patients.

PRES-like leukoencephalopathy presenting with status epilepticus associated with Brentuximab Vedotin treatment

Posterior Reversible Encephalopathy Syndrome (PRES) is characterized by acute neurological symptoms with typical imaging features, primarily in the territories of the brain supplied by the posterior circulation, probably due to vasogenic edema. Both clinical and imaging features are generally reversible. We report a 13-year-old girl affected by Nodular Sclerosis Classical Hodgkin Lymphoma stage IIIB into complete remission, with a recurrence and autologous bone-marrow transplantation, who has been treated with an anti-CD30 monoclonal antibody, brentuximab-vedotin. The girl has suddenly presented a convulsive status epilepticus, that needed intubation and sedation. Therefore, an IV therapy with levetiracetam was started. Furthermore, the girl has presented high blood pressure and reduced kidney function. Brain MRI demonstrated a diffuse PRES-like disease, that went into regression after the first week. After another week, the girl presented a new prolonged generalized tonic clonic convulsive episode, that needed intubation and sedation and an association of clobazam and levetiracetam: a new brain MRI showed a recurrence of PRES-like lesions in addition to some signs of leukoencephalopathy with brain lactate accumulation on 1H-MRS, due to cerebral energetic failure. The girl also presented a refractory arterial hypertension. After 45 days of ICU hospitalization the patient has been discharged and followed up with neurological examinations. Brain MRI and brain 1H-MRS, 5 months after patient's discharge, showed incomplete regression of cerebral white matter signal abnormalities with MRS normalization.

Gene Polymorphisms Increasing the Risk of Intracranial Aneurysms: Interleukin-1β -511C>T (Part I)

Introduction Intracranial aneurysms (IAs) are devastating cerebrovascular diseases with multifactorial etiology. The role of inflammation is indisputable, and interleukins are pivotal in supporting local inflammatory pathways and endothelial dysfunction at the aneurysm wall. In the light of insufficient evidence reported in the literature, this meta-analysis was aimed to investigate the genetic linkage between IL-1β (rs16944) -511C>T polymorphisms and IAs susceptibility. Methods A comprehensive online literature review was completed using the PubMed/Medline and Web of Science databases in accordance with the PRISMA guidelines. "Interleukin-1β," "IL-1β," "polymorphism," "intracranial aneurysm," and "subarachnoid hemorrhage" were the main keywords. Only human case-control studies, published from 2005 to 2021, written in English or translated, were screened. In the statistical analysis, we applied the fixed- and random-effect models, according to the level of heterogeneity, to assess the odds ratios (ORs) and 95% confidence intervals (CIs). RevMan 5.0 software was used for the statistics. Results Only 4 studies were eligible, with a total of 2070 patients, 1050 of which were assigned to the study group. Combined results showed a statistically significant association between the risk of IAs and -511CC (OR=0.79, 95% CI [0.65-0.95], p=0.01), and CT (OR=0.69, 95% CI [0.58-0.82], p<0.0001; OR=0.71, 95% CI [0.55-0.93], p=0.01) allele variations, both in the fixed- and random- models. No correlation was identified for the -511TT genotype (p=0.42; p=0.78). All the texts showed a low level of publication bias. Conclusion The present meta-analysis proved a potential role of IL-1β -511CC/CT genotypes in the pathogenesis of IAs. Additional studies are imperative to explain the underlying neuroimmune mechanisms, also allowing tailoring the potential inflammatory-target therapies for IAs.