The Updated World Health Organization Glioma Classification: Cellular and Molecular Origins of Adult Infiltrating Gliomas

Progress and Challenges in the Diagnosis and Treatment of Brain Cancer Using Nanotechnology

Primary brain cancer or brain cancer is the overgrowth of abnormal or malignant cells in the brain or its nearby tissues that form unwanted masses called brain tumors. People with malignant brain tumors suffer a lot, and the expected life span of the patients after diagnosis is often only around 14 months, even with the most vigorous therapies. The blood-brain barrier (BBB) is the main barrier in the body that restricts the entry of potential chemotherapeutic agents into the brain. The chances of treatment failure or low therapeutic effects are some significant drawbacks of conventional treatment methods. However, recent advancements in nanotechnology have generated hope in cancer treatment. Nanotechnology has shown a vital role starting from the early detection, diagnosis, and treatment of cancer. These tiny nanomaterials have great potential to deliver drugs across the BBB. Beyond just drug delivery, nanomaterials can be simulated to generate fluorescence to detect tumors. The current Review discusses in detail the challenges of brain cancer treatment and the application of nanotechnology to overcome those challenges. The success of chemotherapeutic treatment or the surgical removal of tumors requires proper imaging. Nanomaterials can provide imaging and therapeutic benefits for cancer. The application of nanomaterials in the diagnosis and treatment of brain cancer is discussed in detail by reviewing past studies.

Towards a single-assay approach: a combined DNA/RNA sequencing panel eliminates diagnostic redundancy and detects clinically-relevant fusions in neuropathology

Since the introduction of integrated histological and molecular diagnoses by the 2016 World Health Organization (WHO) Classification of Tumors of the Nervous System, an increasing number of molecular markers have been found to have prognostic significance in infiltrating gliomas, many of which have now become incorporated as diagnostic criteria in the 2021 WHO Classification. This has increased the applicability of targeted-next generation sequencing in the diagnostic work-up of neuropathology specimens and in addition, raises the question of whether targeted sequencing can, in practice, reliably replace older, more traditional diagnostic methods such as immunohistochemistry and fluorescence in-situ hybridization. Here, we demonstrate that the Oncomine Cancer Gene Mutation Panel v2 assay targeted-next generation sequencing panel for solid tumors is not only superior to IHC in detecting mutation in IDH1/2 and TP53 but can also predict 1p/19q co-deletion with high sensitivity and specificity relative to fluorescence in-situ hybridization by looking at average copy number of genes sequenced on 1p, 1q, 19p, and 19q. Along with detecting the same molecular data obtained from older methods, targeted-next generation sequencing with an RNA sequencing component provides additional information regarding the presence of RNA based alterations that have diagnostic significance and possible therapeutic implications. From this work, we advocate for expanded use of targeted-next generation sequencing over more traditional methods for the detection of important molecular alterations as a part of the standard diagnostic work up for CNS neoplasms.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of neuropathology in the management of progressive glioblastoma in adults

TARGET POPULATION

These recommendations apply to adult patients with progressive or recurrent glioblastoma (GBM).

QUESTION

For adult patients with progressive glioblastoma does testing for Isocitrate Dehydrogenase (IDH) 1 or 2 mutations provide new additional management or prognostic information beyond that derived from the tumor at initial presentation?

RECOMMENDATION

Level III: Repeat IDH mutation testing is not necessary if the tumor is histologically similar to the primary tumor and the patient's clinical course is as expected.

QUESTION

For adult patients with progressive glioblastoma does repeat testing for MGMT promoter methylation provide new or additional management or prognostic information beyond that derived from the tumor at initial presentation and what methods of detection are optimal?

RECOMMENDATION

Level III: Repeat MGMT promoter methylation is not recommended.

QUESTION

For adult patients with progressive glioblastoma does EGFR amplification or mutation testing provide management or prognostic information beyond that provided by histologic analysis and if performed on previous tissue samples, does it need to be repeated?

RECOMMENDATION

Level III: In cases that are difficult to classify as glioblastoma on histologic features EGFR amplification testing may help in classification. If a previous EGFR amplification was detected, repeat testing is not necessary. Repeat EGFR amplification or mutational testing may be recommended in patients in which target therapy is being considered.

QUESTION

For adult patients with progressive glioblastoma does large panel or whole genome sequencing provide management or prognostic information beyond that derived from histologic analysis?

RECOMMENDATION

Level III: Primary or repeat large panel or whole genome sequencing may be considered in patients who are eligible or interested in molecularly guided therapy or clinical trials.

QUESTION

For adult patients with progressive glioblastoma should immune checkpoint biomarker testing be performed to provide management and prognostic information beyond that obtained from histologic analysis?

RECOMMENDATION

Level III: The current evidence does not support making PD-L1 or mismatch repair (MMR) enzyme activity a component of standard testing.

QUESTION

For adult patients with progressive glioblastoma are there meaningful biomarkers for bevacizumab responsiveness and does their assessment provide additional information for tumor management and prognosis beyond that learned by standard histologic analysis?

RECOMMENDATION

Level III: No established Bevacizumab biomarkers are currently available based upon the inclusion criteria of this guideline.

The Interplay of Microtubules with Mitochondria–ER Contact Sites (MERCs) in Glioblastoma

Gliomas are heterogeneous neoplasms, classified into grade I to IV according to their malignancy and the presence of specific histological/molecular hallmarks. The higher grade of glioma is known as glioblastoma (GB). Although progress has been made in surgical and radiation treatments, its clinical outcome is still unfavorable. The invasive properties of GB cells and glioma aggressiveness are linked to the reshaping of the cytoskeleton. Recent works suggest that the different susceptibility of GB cells to antitumor immune response is also associated with the extent and function of mitochondria–ER contact sites (MERCs). The presence of MERCs alterations could also explain the mitochondrial defects observed in GB models, including abnormalities of energy metabolism and disruption of apoptotic and calcium signaling. Based on this evidence, the question arises as to whether a MERCs–cytoskeleton crosstalk exists, and whether GB progression is linked to an altered cytoskeleton–MERCs interaction. To address this possibility, in this review we performed a meta-analysis to compare grade I and grade IV GB patients. From this preliminary analysis, we found that GB samples (grade IV) are characterized by altered expression of cytoskeletal and MERCs related genes. Among them, the cytoskeleton-associated protein 4 (CKAP4 or CLIMP-63) appears particularly interesting as it encodes a MERCs protein controlling the ER anchoring to microtubules (MTs). Although further in-depth analyses remain necessary, this perspective review may provide new hints to better understand GB molecular etiopathogenesis, by suggesting that cytoskeletal and MERCs alterations cooperate to exacerbate the cellular phenotype of high-grade GB and that MERCs players can be exploited as novel biomarkers/targets to enhance the current therapy for GB.

Diffuse astrocytoma with mosaic IDH1-R132H-mutant immuno-phenotype and low subclonal allele frequency

Molecular alterations found in gliomas are now considered entity-defining features. The World Health Organization (WHO) classification system currently classifies the vast majority of gliomas utilizing an integrated genotype-phenotype approach. We present a case of diffuse astrocytoma with a mosaic isocitrate dehydrogenase (IDH)1-R132H-mutant immunophenotype and low subclonal allele frequency. A 35-year-old patient with a history of IDH1-R132H mutated diffuse astrocytoma in 20014 presented to the hospital again in 2019. MRI examination showed a non-enhancing abnormal signal in the periphery of her previous surgical cavity. Histopathological examination revealed that the tumor was hypercellular and without high grade histopathological features. The neoplastic cells were immunohistologically positive for GFAP, Olig2, and ATRX. However, only some scattered tumor cells were positive for IDH1-R132H. Cytogenetic studies revealed a lack of chromosomal 1p/19q co-deletion. Further next-generation sequencing (NGS) demonstrated a low-level IDH1-R132H mutation and allele frequency. Based on these findings, the diagnosis of diffuse astrocytoma with mosaic IDH1- R132H-mutant immunophenotype and low subclonal allele frequency (WHO grade II) was generated. This case indicates that gliomas may have heterogeneous molecular profile and the intra-tumoral molecular heterogeneity highlights the need to further characterize the molecular profile for glioma classification and clinical management.

Lidocaine liposome modified with folic acid suppresses the proliferation and motility of glioma cells via targeting the PI3K/AKT pathway

Glioma is life-threatening tumor of the central nervous system. Although lidocaine is usually used as local anesthetic, it also has antitumor effects. However, its clinical application in glioma is hampered by limited distribution to the brain. The aim of the present study was to enhance the ability of lidocaine to penetrate the blood-brain barrier (BBB) to target glioma and investigate its antitumor mechanism. A folic acid (FA)-modified lidocaine-carrying liposome (Lid-FA-Lip) was prepared, and its particle size, ζ potential, encapsulation efficiency, release profile stability and hemolytic effect were characterized in vitro. The targeting capacity and antitumor activities of Lid-FA-Lip were also investigated in vitro and in vivo. The results indicated that the modification of liposomes with FA significantly improved the ability of lidocaine to cross the BBB in an in vitro model and increased its uptake by U87 cells. Additionally, Lid-FA-Lip significantly suppressed the motility of U87 glioma cells and stimulated apoptosis. Furthermore, the results confirmed that Lid-FA-Lip targeted the PI3K/AKT pathway and suppressed the growth of glioma xenografts in mice. In summary, the study demonstrated that Lid-FA-Lip is a promising liposomal formulation of lidocaine that may provide improved therapeutic effects on glioma, mediated via the PI3K/AKT pathway.

Multiregional Sequencing of IDH-WT Glioblastoma Reveals High Genetic Heterogeneity and a Dynamic Evolutionary History

Simple Summary

Glioblastoma is the most common and aggressive primary brain malignancy in adults. In addition to extensive inter-patient heterogeneity, glioblastoma shows intra-tumor extensive cellular and molecular heterogeneity, both spatially and temporally. This heterogeneity is one of the main reasons for the poor prognosis and overall survival. Moreover, it raises the important question of whether the molecular characterization of a single biopsy sample, as performed in standard diagnostics, actually represents the entire lesion. In this study, we sequenced the whole exome of nine spatially different cancer regions of three primary glioblastomas. We characterized their mutational profiles and copy number alterations, with implications for our understanding of tumor biology in relation to clonal architecture and evolutionary dynamics, as well as therapeutically relevant alterations.

Abstract

Glioblastoma is one of the most common and lethal primary neoplasms of the brain. Patient survival has not improved significantly over the past three decades and the patient median survival is just over one year. Tumor heterogeneity is thought to be a major determinant of therapeutic failure and a major reason for poor overall survival. This work aims to comprehensively define intra- and inter-tumor heterogeneity by mapping the genomic and mutational landscape of multiple areas of three primary IDH wild-type (IDH-WT) glioblastomas. Using whole exome sequencing, we explored how copy number variation, chromosomal and single loci amplifications/deletions, and mutational burden are spatially distributed across nine different tumor regions. The results show that all tumors exhibit a different signature despite the same diagnosis. Above all, a high inter-tumor heterogeneity emerges. The evolutionary dynamics of all identified mutations within each region underline the questionable value of a single biopsy and thus the therapeutic approach for the patient. Multiregional collection and subsequent sequencing are essential to try to address the clinical challenge of precision medicine. Especially in glioblastoma, this approach could provide powerful support to pathologists and oncologists in evaluating the diagnosis and defining the best treatment option.

Peri-tumoral brain edema associated with glioblastoma correlates with tumor recurrence

Glioblastoma is the most common malignant tumor of the brain. Despite advances in treatment, the prognosis for the condition has remained poor. Glioblastoma is often associated with peritumoral brain edema (PTBE), which can result in increased intracranial pressure and devastating neurological sequelae if left untreated. Surgery is the main treatment for glioblastoma, however current international surgical guidelines do not specify whether glioblastoma-induced PTBE tissue should be resected. In this study, we analyzed treatment outcomes of PTBE using surgical resection. We performed a retrospective analysis of 255 cases of glioblastoma between 2014 and 2016, and found that a significant proportion of patients had a degree of PTBE. We found that surgical resection led to reduction in midline shift that had resulted from edema, however, postoperative complications and KPS scores were not significantly different in the two conditions. We also observed a delay in glioblastoma recurrence in patients undergoing PTBE tissue resection vs patients without resection of PTBE tissue. Interestingly, there was an abnormal expression of tumor associated genes in PTBE, which has not been previously been found. Taken together, this study indicates that glioblastoma-induced PTBE should be investigated further particularly as the tumor microenvironment is a known therapeutic target and therefore interactions between the microenvironment and PTBE should be explored. This study also highlights the importance of resection of PTBE tissue to not only reduce the mechanical obstruction associated with edema but also to delay recurrence of glioblastoma.

The Past, Present and Future of Flow Cytometry in Central Nervous System Malignancies

Central nervous system malignancies (CNSMs) are categorized among the most aggressive and deadly types of cancer. The low median survival in patients with CNSMs is partly explained by the objective difficulties of brain surgeries as well as by the acquired chemoresistance of CNSM cells. Flow Cytometry is an analytical technique with the ability to quantify cell phenotype and to categorize cell populations on the basis of their characteristics. In the current review, we summarize the Flow Cytometry methodologies that have been used to study different phenotypic aspects of CNSMs. These include DNA content analysis for the determination of malignancy status and phenotypic characterization, as well as the methodologies used during the development of novel therapeutic agents. We conclude with the historical and current utility of Flow Cytometry in the field, and we propose how we can exploit current and possible future methodologies in the battle against this dreadful type of malignancy.

The Organoid Era Permits the Development of New Applications to Study Glioblastoma

Glioblastoma (GB) is the most frequent and aggressive type of glioma. The lack of reliable GB models, together with its considerable clinical heterogeneity, has impaired a comprehensive investigation of the mechanisms that lead to tumorigenesis, cancer progression, and response to treatments. Recently, 3D cultures have opened the possibility to overcome these challenges and cerebral organoids are emerging as a leading-edge tool in GB research. The opportunity to easily engineer brain organoids via gene editing and to perform co-cultures with patient-derived tumor spheroids has enabled the analysis of cancer development in a context that better mimics brain tissue architecture. Moreover, the establishment of biobanks from GB patient-derived organoids represents a crucial starting point to improve precision medicine therapies. This review exemplifies relevant aspects of 3D models of glioblastoma, with a specific focus on organoids and their involvement in basic and translational research.

Knockdown of TRIM47 inhibits glioma cell proliferation, migration and invasion through the inactivation of Wnt/β-catenin pathway

Tripartite motif 47 (TRIM47), a member of the TRIM protein family, plays a crucial role in tumor development and progression. However, the role of TRIM47 in glioma has not been investigated. In the present study, we investigated the expression of TRIM47 in glioma and explored the role of TRIM47 in glioma proliferation and migration both in vitro and in vivo. Our results showed that TRIM47 expression was significantly increased in glioma tissues compared to the normal brain tissues. Knockdown of TRIM47 in U87 and U251 cells inhibited cell proliferation, as well as cell migration and invasion. TRIM47 knockdown caused significant increase in E-cadherin expression and remarkable decrease in N-cadherin and vimentin expressions in both U87 and U251 cells. In vivo assay proved that knockdown of TRIM47 prevented tumor growth of glioma. Furthermore, TRIM47 silencing significantly inhibited the activation of Wnt/β-catenin pathway. Additionally, treatment with LiCl reversed the inhibitory effects of TRIM47 knockdown on cell proliferation and migration in U87 cells. In conclusion, these findings indicated that knockdown of TRIM47 suppressed cell proliferation and metastasis of glioma both in vitro and in vivo. TRIM47 exerted an oncogenic role in glioma and might be a therapeutic target for the treatment of glioma.

The Influence of Nutritional and Lifestyle Factors on Glioma Incidence

Cancers are the first main cause of premature death in developed countries. Since brain tumors, especially gliomas, are the most lethal type of cancers, risk factors for their prevalence are still being discussed. Nearly 30–50% of all cancers could be prevented by proper nutritional habits and other lifestyle factors, but their influence on the tumors of the central nervous system has not been explained completely and still requires further studies. That is why we attempted to review the available research in this field, with a special focus on the factors with the proven protective activity observed in other cancers. Adequate vegetables and antioxidants (such as vitamins C and A) provided with a diet could have a protective effect, while other factors have shown no correlation with the incidence of glioma. However, further studies are necessary to determine whether fish, coffee, and tea consumption may prevent glioma. Maintaining proper body weight and undertaking a sufficient level of daily physical activity also seem to be important. Excessive body mass index (BMI) and higher attained height have increased the risk of glioma. In order to link more accurately the chosen factors to the prevalence of gliomas, it seems necessary to conduct large cohort, prospective, controlled studies in different world regions.

Targeting of endoplasmic reticulum (ER) stress in gliomas

Gliomas remain a group of malignant brain tumors with dismal prognosis and limited treatment options with molecular mechanisms being constantly investigated. The past decade, extracellular stress and intracellular DNA damage have been shown to disturb proteostasis leading to Endoplasmic Reticulum (ER) stress that is implicated in the regulation of gene expression and the pathogenesis of several tumor types, including gliomas. Upon ER stress induction, neoplastic cells activate the adaptive mechanism of unfolded protein response (UPR), an integrated signaling system that either restores ER homeostasis or induces cell apoptosis. Recently, the manipulation of the UPR has emerged as a new therapeutic target in glioma treatment. General UPR activators or selective GRP78, ATF6 and PERK inducers have been detected to modulate cell proliferation and induce apoptosis of glioma cells. At the same time, target-specific UPR inhibitors and small molecule proteostasis disruptors, work in reverse to increase misfolded proteins and cause a dysregulation in protein maturation and sorting, thus preventing the growth of neoplastic cells. Herein, we discuss the pathogenic implication of ER stress in gliomas onset and progression, providing an update on the current UPR modifying agents that can be potentially used in glioma treatment.

Sphere-Forming Culture for Expanding Genetically Distinct Patient-Derived Glioma Stem Cells by Cellular Growth Rate Screening

Diffusely infiltrating gliomas (DIGs) are difficult to completely resect and are associated with a high rate of tumor relapse and progression from low- to high-grade glioma. In particular, optimized short-term culture-enriching patient-derived glioma stem cells (GSCs) are essential for customizing the therapeutic strategy based on clinically feasible in vitro drug screening for a wide range of DIGs, owing to the high inter-tumoral heterogeneity. Herein, we constructed a novel high-throughput culture condition screening platform called ‘GFSCAN’, which evaluated the cellular growth rates of GSCs for each DIG sample in 132 serum-free combinations, using 13 previously reported growth factors closely associated with glioma aggressiveness. In total, 72 patient-derived GSCs with available genomic profiles were tested in GFSCAN to explore the association between cellular growth rates in specific growth factor combinations and genomic/molecular backgrounds, including isocitrate dehydrogenase 1 (IDH1) mutation, chromosome arm 1p and 19q co-deletion, ATRX chromatin remodeler alteration, and transcriptional subtype. GSCs were clustered according to the dependency on epidermal growth factor and basic fibroblast growth factor (E&F), and isocitrate dehydrogenase 1 (IDH1) wild-type GSCs showed higher E&F dependencies than IDH1 mutant GSCs. More importantly, we elucidated optimal combinations for IDH1 mutant glioblastoma and lower grade glioma GSCs with low dependencies on E&F, which could be an aid in clinical decision-making for these DIGs. Thus, we demonstrated the utility of GFSCAN in personalizing in vitro cultivation to nominate personalized therapeutic options, in a clinically relevant time frame, for individual DIG patients, where standard clinical options have been exhausted.

Copy number assessment in the genomic analysis of CNS neoplasia: An evidence-based review from the cancer genomics consortium (CGC) working group on primary CNS tumors

The period from the 1990s to the 2010s has witnessed a burgeoning sea change in the practice of surgical neuropathology due to the incorporation of genomic data into the assessment of a range of central nervous system (CNS) neoplasms. This change has since matured into the adoption of genomic information into the definition of several World Health Organization (WHO)-established diagnostic entities. The data needed to accomplish the modern diagnosis of CNS neoplasia includes DNA copy number aberrations that may be assessed through a variety of mechanisms. Through a review of the relevant literature and professional practice guidelines, here we provide a condensed and scored overview of the most critical DNA copy number aberrations to assess for a selection of primary CNS neoplasms.

Therapeutic Efficiency of Multiple Applications of Magnetic Hyperthermia Technique in Glioblastoma Using Aminosilane Coated Iron Oxide Nanoparticles: In Vitro and In Vivo Study

Magnetic hyperthermia (MHT) has been shown as a promising alternative therapy for glioblastoma (GBM) treatment. This study consists of three parts: The first part evaluates the heating potential of aminosilane-coated superparamagnetic iron oxide nanoparticles (SPIONa). The second and third parts comprise the evaluation of MHT multiple applications in GBM model, either in vitro or in vivo. The obtained heating curves of SPIONa (100 nm, +20 mV) and their specific absorption rates (SAR) stablished the best therapeutic conditions for frequencies (309 kHz and 557 kHz) and magnetic field (300 Gauss), which were stablished based on three in vitro MHT application in C6 GBM cell line. The bioluminescence (BLI) signal decayed in all applications and parameters tested and 309 kHz with 300 Gauss have shown to provide the best therapeutic effect. These parameters were also established for three MHT applications in vivo, in which the decay of BLI signal correlates with reduced tumor and also with decreased tumor glucose uptake assessed by positron emission tomography (PET) images. The behavior assessment showed a slight improvement after each MHT therapy, but after three applications the motor function displayed a relevant and progressive improvement until the latest evaluation. Thus, MHT multiple applications allowed an almost total regression of the GBM tumor in vivo. However, futher evaluations after the therapy acute phase are necessary to follow the evolution or tumor total regression. BLI, positron emission tomography (PET), and spontaneous locomotion evaluation techniques were effective in longitudinally monitoring the therapeutic effects of the MHT technique.

Intraoperative assessment of isocitrate dehydrogenase mutation status in human gliomas using desorption electrospray ionization-mass spectrometry

OBJECTIVE

The authors describe a rapid intraoperative ambient ionization mass spectrometry (MS) method for determining isocitrate dehydrogenase (IDH) mutation status from glioma tissue biopsies. This method offers new glioma management options and may impact extent of resection goals. Assessment of the IDH mutation is key for accurate glioma diagnosis, particularly for differentiating diffuse glioma from other neoplastic and reactive inflammatory conditions, a challenge for the standard intraoperative diagnostic consultation that relies solely on morphology.

METHODS

Banked glioma specimens (n = 37) were analyzed by desorption electrospray ionization-MS (DESI-MS) to develop a diagnostic method to detect the known altered oncometabolite in IDH-mutant gliomas, 2-hydroxyglutarate (2HG). The method was used intraoperatively to analyze tissue smears obtained from glioma patients undergoing resection and to rapidly diagnose IDH mutation status (< 5 minutes). Fifty-one tumor core biopsies from 25 patients (14 wild type [WT] and 11 mutant) were examined and data were analyzed using analysis of variance and receiver operating characteristic curve analysis.

RESULTS

The optimized DESI-MS method discriminated between IDH-WT and IDH-mutant gliomas, with an average sensitivity and specificity of 100%. The average normalized DESI-MS 2HG signal was an order of magnitude higher in IDH-mutant glioma than in IDH-WT glioma. The DESI 2HG signal intensities correlated with independently measured 2HG concentrations (R2 = 0.98). In 1 case, an IDH1 R132H-mutant glioma was misdiagnosed as a demyelinating condition by frozen section histology during the intraoperative consultation, and no resection was performed pending the final pathology report. A second craniotomy and tumor resection was performed after the final pathology provided a diagnosis most consistent with an IDH-mutant glioblastoma. During the second craniotomy, high levels of 2HG in the tumor core biopsies were detected.

CONCLUSIONS

This study demonstrates the capability to differentiate rapidly between IDH-mutant gliomas and IDH-WT conditions by DESI-MS during tumor resection. DESI-MS analysis of tissue smears is simple and can be easily integrated into the standard intraoperative pathology consultation. This approach may aid in solving differential diagnosis problems associated with low-grade gliomas and could influence intraoperative decisions regarding extent of resection, ultimately improving patient outcome. Research is ongoing to expand the patient cohort, systematically validate the DESI-MS method, and investigate the relationships between 2HG and tumor heterogeneity.

Targeting the Sphingolipid System as a Therapeutic Direction for Glioblastoma

Glioblastoma (GBM) is the most commonly diagnosed malignant brain tumor in adults. The prognosis for patients with GBM remains poor and largely unchanged over the last 30 years, due to the limitations of existing therapies. Thus, new therapeutic approaches are desperately required. Sphingolipids are highly enriched in the brain, forming the structural components of cell membranes, and are major lipid constituents of the myelin sheaths of nerve axons, as well as playing critical roles in cell signaling. Indeed, a number of sphingolipids elicit a variety of cellular responses involved in the development and progression of GBM. Here, we discuss the role of sphingolipids in the pathobiology of GBM, and how targeting sphingolipid metabolism has emerged as a promising approach for the treatment of GBM.

Characteristics and prognostic factors of age-stratified high-grade intracranial glioma patients: A population-based analysis

We evaluated characteristics and different prognostic factors for survival in age-stratified high-grade glioma in a U.S. cohort. Eligible patients were identified in the Surveillance, Epidemiology, and End Results (SEER) registries and stratified into 3 age groups: 20-39 years old (1,043 patients), 40-59 years old (4,503 patients), and >60 years old (5,045 patients). Overall and cancer-related survival data were obtained. Cox models were built to analyze the outcomes and risk factors. It showed that race was a prognostic factor for survival in patients 40 to 59 years old and in patients ≥60 years old. Partial resection was associated with lower overall survival and cause-specific survival in all age groups (overall survival: 20-39 yr: HR = 6.41; 40-59 yr: HR = 4.84; >60 yr: HR = 5.06; cause-specific survival: 20-39 yr: HR = 5.87; 40-59 yr: HR = 4.01; >60 yr: HR = 3.36). The study highlights that, while some prognostic factors are universal, others are age-dependent. The effectiveness of treatment approaches differs for patients in different age groups. Results of this study may help to develop personalized treatment protocols for glioma patients of different ages.

Similarities Between Stem Cell Niches in Glioblastoma and Bone Marrow: Rays of Hope for Novel Treatment Strategies

Glioblastoma is the most aggressive primary brain tumor. Slowly dividing and therapy-resistant glioblastoma stem cells (GSCs) reside in protective peri-arteriolar niches and are held responsible for glioblastoma recurrence. Recently, we showed similarities between GSC niches and hematopoietic stem cell (HSC) niches in bone marrow. Acute myeloid leukemia (AML) cells hijack HSC niches and are transformed into therapy-resistant leukemic stem cells (LSCs). Current clinical trials are focussed on removal of LSCs out of HSC niches to differentiate and to become sensitized to chemotherapy. In the present study, we elaborated further on these similarities by immunohistochemical analyses of 17 biomarkers in paraffin sections of human glioblastoma and human bone marrow. We found all 17 biomarkers to be expressed both in hypoxic peri-arteriolar HSC niches in bone marrow and hypoxic peri-arteriolar GSC niches in glioblastoma. Our findings implicate that GSC niches are being formed in glioblastoma as a copy of HSC niches in bone marrow. These similarities between HSC niches and GSC niches provide a theoretic basis for the development of novel strategies to force GSCs out of their niches, in a similar manner as in AML, to induce GSC differentiation and proliferation to render them more sensitive to anti-glioblastoma therapies.

Reclassification of Mongolian Diffuse Gliomas According to the Revised 2016 World Health Organization Central Nervous System Tumor Classification

Background

The 2016 World Health Organization (WHO) classification of central nervous system (CNS) tumors has been modified to incorporate the IDH mutation and 1p/19q co-deletion in the diagnosis of diffuse gliomas. In this study, we aimed to evaluate the feasibility and prognostic significance of the revised 2016 WHO classification of CNS tumors in Mongolian patients with diffuse gliomas.

Methods

A total of 124 cases of diffuse gliomas were collected, and tissue microarray blocks were made. IDH1 mutation was tested using immunohistochemistry, and 1p/19q co-deletion status was examined using fluorescence in situ hybridization analysis.

Results

According to the 2016 WHO classification, 124 cases of diffuse brain glioma were reclassified as follows: 10 oligodendroglioma, IDH^mut and 1p/19q co-deleted; three anaplastic oligodendroglioma, IDH^mut and 1p/19q co-deleted; 35 diffuse astrocytoma, IDH^mut, 11 diffuse astrocytoma, IDH^wt, not otherwise specified (NOS); 22 anaplastic astrocytoma, IDH^mut, eight anaplastic astrocytoma, IDH^wt, NOS; and 35 glioblastoma, IDH^wt, NOS, respectively. The 2016 WHO classification presented better prognostic value for overall survival in patients with grade II tumors than traditional histological classification. Among patients with grade II tumors, those with oligodendroglioma IDH^mut and 1p/19q co-deleted and diffuse astrocytoma IDH^mut showed significantly higher survival than those with diffuse astrocytoma IDH^wt, NOS (p<.01).

Conclusions

Mongolian diffuse gliomas could be reclassified according to the new 2016 WHO classification. Reclassification revealed substantial changes in diagnosis of both oligodendroglial and astrocytic entities. We have confirmed that the revised 2016 WHO CNS tumor classification has prognostic significance in Mongolian patients with diffuse gliomas, especially those with grade II tumors.

miR-25-3p promotes glioma cell proliferation and migration by targeting FBXW7 and DKK3

MicroRNAs (miRs) serve important roles in glioma. However, the underlying molecular mechanism of miR-25 in glioma progression remains largely unknown; therefore, it was investigated in the present study. RT-qPCR analysis revealed that miR-25 expression levels were markedly increased in human glioma tissue and glioma cell lines compared with normal brain tissues and normal human astrocytes, respectively. miR-25 upregulation exhibited an association with glioma progression, and the knockdown of miR-25 significantly inhibited glioma cell proliferation and migration. F-box and WD repeat domain containing 7 (FBXW7) and dickkopf WNT signaling pathway inhibitor 3 (DKK3) were identified as target genes of miR-25. FBXW7 and DKK3 expression levels were significantly downregulated in glioma tissue samples compared with normal brain tissue, and their expression levels were negatively regulated by miR-25 expression in glioma cells. Furthermore, inhibition of FBXW7 and DKK3 expression suppressed the miR-25-induced effects on glioma cell proliferation and migration. The findings of the present study suggest that miR-25 may promote glioma cell proliferation and migration by inhibiting the expression of FBXW7 and DKK3. Therefore, miR-25 may serve as a promising molecular target for the treatment of glioma.

Glioblastoma heterogeneity and the tumour microenvironment: implications for preclinical research and development of new treatments

Glioblastoma is the deadliest form of brain cancer. Aside from inadequate treatment options, one of the main reasons glioblastoma is so lethal is the rapid growth of tumour cells coupled with continuous cell invasion into surrounding healthy brain tissue. Significant intra- and inter-tumour heterogeneity associated with differences in the corresponding tumour microenvironments contributes greatly to glioblastoma progression. Within this tumour microenvironment, the extracellular matrix profoundly influences the way cancer cells become invasive, and changes to extracellular (pH and oxygen levels) and metabolic (glucose and lactate) components support glioblastoma growth. Furthermore, studies on clinical samples have revealed that the tumour microenvironment is highly immunosuppressive which contributes to failure in immunotherapy treatments. Although technically possible, many components of the tumour microenvironment have not yet been the focus of glioblastoma therapies, despite growing evidence of its importance to glioblastoma malignancy. Here, we review recent progress in the characterisation of the glioblastoma tumour microenvironment and the sources of tumour heterogeneity in human clinical material. We also discuss the latest advances in technologies for personalised and in vitro preclinical studies using brain organoid models to better model glioblastoma and its interactions with the surrounding healthy brain tissue, which may play an essential role in developing new and more personalised treatments for this aggressive type of cancer.

The Volume-Regulated Anion Channel in Glioblastoma

Malignancy of glioblastoma multiforme (GBM), the most common and aggressive form of human brain tumor, strongly depends on its enhanced cell invasion and death evasion which make surgery and accompanying therapies highly ineffective. Several ion channels that regulate membrane potential, cytosolic Ca²⁺ concentration and cell volume in GBM cells play significant roles in sustaining these processes. Among them, the volume-regulated anion channel (VRAC), which mediates the swelling-activated chloride current (IClswell) and is highly expressed in GBM cells, arguably plays a major role. VRAC is primarily involved in reestablishing the original cell volume that may be lost under several physiopathological conditions, but also in sustaining the shape and cell volume changes needed for cell migration and proliferation. While experimentally VRAC is activated by exposing cells to hypotonic solutions that cause the increase of cell volume, in vivo it is thought to be controlled by several different stimuli and modulators. In this review we focus on our recent work showing that two conditions normally occurring in pathological GBM tissues, namely high serum levels and severe hypoxia, were both able to activate VRAC, and their activation was found to promote cell migration and resistance to cell death, both features enhancing GBM malignancy. Also, the fact that the signal transduction pathway leading to VRAC activation appears to involve GBM specific intracellular components, such as diacylglicerol kinase and phosphatidic acid, reportedly not involved in the activation of VRAC in healthy tissues, is a relevant finding. Based on these observations and the impact of VRAC in the physiopathology of GBM, targeting this channel or its intracellular regulators may represent an effective strategy to contrast this lethal tumor.

The Increased Expression of Estrogen-Related Receptor α Correlates with Wnt5a and Poor Prognosis in Patients with Glioma

Malignant glioma is an often fatal type of cancer. Elevated expression of the orphan nuclear receptor estrogen-related receptor alpha (ERRα) is an unfavorable factor for malignant progression and poor prognosis in several cancers, although the mechanism by which this receptor affects the pathophysiology of cancers remains obscure. However, few studies have been conducted in regard to the role of ERRα in glioma. In the current study, we found that elevated expression of ERRα was observed in 107 glioma cases by means of IHC. Clinically, high expression of ERRα was associated with later stages of disease progression and clinical outcome of patients with glioma. ERRα had the ability to promote cell proliferation and migration in glioma cell lines. Moreover, in a xenograft model, we also found that silencing ERRα had an inhibitory effect on the growth of glioma. Further investigation confirmed that ERRα was involved in the carcinogenesis of glioma via the regulation of the Wnt5a signal pathway in vitro and in vivo Our study was first to show the overexpression of ERRα in glioma tissues and a direct correlation between ERRα expression and clinical prognosis of glioma. Together, these data reveal that ERRα has prognostic significance in glioma, and targeting ERRα may provide a reliable therapeutic strategy for the treatment for human glioma.

WZY-321, a novel evodiamine analog, inhibits glioma cell growth in an autophagy-associated manner

Glioblastoma is one of the most aggressive types of brain tumor. The median survival rate of patients with glioblastoma (World Health Organization grade IV) is <15 months. Therefore, there is an urgent requirement for the development of novel and efficient therapeutic agents against glioma. In previous studies, WZY-321 (10-hydroxy-1-methyl-8,13b-dihydro-5H,7H-benzo[e]benzofuro[2',3':3,4]pyrido[2,1-b][1,3]oxazin-5-one), a novel evodiamine (Evo) analog, was reported to exhibit enhanced pharmacological properties and improved cytotoxicity against a number of human cancer cell lines compared with Evo. In the current study, the anti-proliferative effect of WZY-321 on SHG-44 and SWO-38 glioma cells was further studied, and its mechanism of action investigated. The results indicated that WZY-321 inhibited the proliferation of SHG-44 cells in a dose- and time-dependent manner by enhancing cellular apoptosis and inducing cell cycle arrest at the G2-M phase. Treatment of glioma cells with WZY-321 concomitantly increased the expression levels of microtubule associated protein 1 light chain 3α and Beclin1, indicating enhanced autophagy. Overall, the results of the present study revealed the anti-proliferative potential of WZY-321 in glioma cells, thus providing a possible autophagy-based therapeutic strategy for the treatment of glioblastoma.