Current Opinion on Molecular Characterization for GBM Classification in Guiding Clinical Diagnosis, Prognosis, and Therapy

Microtubule actin crosslinking factor 1, a brain tumor oncoprotein (Review)

Microtubule actin crosslinking factor 1 (MACF1), is a cytoskeletal protein that functions as a crosslinker between microtubules and actin filaments, with early studies expanding the role of this spectraplakin protein to the central nervous system and Wnt signaling. In the early 2000's, genetic alterations of MACF1 were identified in several cancers suggesting that this cytoskeletal crosslinker was involved in tumor development and progression, while preclinical studies provided evidence that MACF1 is a potential diagnostic and prognostic biomarker and therapeutic target in glioblastomas, a central nervous system cancer derived from astrocytes and neural progenitor stem cells. Furthermore, investigations in glioblastomas demonstrated that genetic inhibitory targeting of this spectraplakin protein alone and in combination with DNA damaging agents had synergistic antitumorigenic effects. The established role of MACF1 in Wnt signaling, a known mechanistic driver of central nervous system development and pro-tumorigenic cell behavior in glioblastomas, provide a premise for addressing the potential of this spectraplakin protein as a novel oncoprotein in cancers with origins in the nervous system. The present review provides a summary of the role and function of MACF1 in the central nervous system, Wnt signaling and cancer development, specifically as an oncoprotein that underlie the transformation and oncogenic properties of glioblastomas.

Deciphering glioblastoma: Unveiling imaging markers for predicting MGMT promoter methylation status

Glioblastoma, the most common primary malignant tumor of the central nervous system in adults, is also among the most lethal. Despite a comprehensive treatment approach which utilizes surgery and postoperative chemoradiation, prognosis typically remains dismal. However certain epigenetic modifications, such as methylation of the MGMT promoter, have been proven to correlate with improved post-treatment outcomes. The 2021 WHO classification emphasizes molecular characteristics, highlighting shared genomic alterations across different grades and positioning MGMT methylation as a key influencer of outcomes. A combined diagnostic approach involving current imaging technology and emerging radiomics and deep learning models may allow for timely and accurate prediction of MGMT methylation status and therefore earlier and more individualized treatment and prognostication. Though these advanced radiomics models are rapidly emerging, additional development, standardization, and implementation may lead to a higher and more individualized level of patient care. This review explores the potential of imaging features in predicting MGMT promoter methylation, a critical determinant of therapeutic response and patient outcomes.

Inhibition of CHI3L1 decreases N-cadherin and VCAM-1 levels in glioblastoma

BACKGROUND

The protein CHI3L1 contributes to cancer development by several mechanisms, including stimulation of angiogenesis and invasion as well as immunomodulatory effects. These properties make it a potential target for the development of targeted therapies in precision medicine. In this context, the particular potential of CHI3L1 inhibition could be considered in glioblastoma multiforme (GBM), whose tumors exhibit high levels of angiogenesis and increased CHI3L1 expression. This study aims to investigate whether inhibition of CHI3L1 in spheroids used as a GBM model affects the mechanisms of invasiveness; METHODS: We analyzed the interactions between CHI3L1 and the inhibitor G721-0282 in molecular docking and molecular dynamics (in silico) and infrared spectroscopy. Uptake of G721-0282 in GBM spheroids was measured using a label-free physical cytometer. Changes in E-, N- and VE-cadherins, VCAM-1, and EGFR were analyzed by immunohistochemical reactions, Western blot, and ddPCR methods in U-87 MG cells and GBM spheroids consisting of U-87 MG glioblastoma cells, HMEC-1 endothelial cells and macrophages; RESULTS: A direct interaction between CHI3L1 and G721-0282 was confirmed. G721-0282 decreased N-cadherins and VCAM-1 in GBM spheroids, but the changes in the 2D model of U-87 MG glioblastoma cells were different; CONCLUSION: Inhibition of CHI3L1 has the potential to reduce the invasiveness of GBM tumors. The 3D model of GBM spheroids is of great significance for investigating changes in membrane proteins and the tumor microenvironment.

Starting points for the development of new targeted therapies for glioblastoma multiforme

Glioblastoma multiforme (GBM) is one of the most aggressive and lethal brain tumors, characterized by rapid growth, invasiveness, and resistance to standard therapies, including surgery, chemotherapy, and radiotherapy. Despite advances in treatment, GBM remains highly resistant due to its complex molecular mechanisms, including angiogenesis, invasion, immune modulation, and lipid metabolism dysregulation. This review explores recent breakthroughs in targeted therapies, focusing on innovative drug carriers such as nanoparticles and liposomes, and their potential to overcome GBM's chemo- and radioresistant phenotypes. We also discuss the molecular pathways involved in GBM progression and the latest therapeutic strategies, including immunotherapy and precision medicine approaches, which hold promise for improving clinical outcomes. The review highlights the importance of understanding GBM's genetic and molecular heterogeneity to develop more effective, personalized treatment protocols aimed at increasing survival rates and enhancing the quality of life for GBM patients.

Recent Developments in Glioblastoma-On-A-Chip for Advanced Drug Screening Applications

Glioblastoma (GBM) is an aggressive form of cancer, comprising ≈80% of malignant brain tumors. However, there are no effective treatments for GBM due to its heterogeneity and the presence of the blood-brain barrier (BBB), which restricts the delivery of therapeutics to the brain. Despite in vitro models contributing to the understanding of GBM, conventional 2D models oversimplify the complex tumor microenvironment. Organ-on-a-chip (OoC) models have emerged as promising platforms that recapitulate human tissue physiology, enabling disease modeling, drug screening, and personalized medicine. There is a sudden increase in GBM-on-a-chip models that can significantly advance the knowledge of GBM etiology and revolutionize drug development by reducing animal testing and enhancing translation to the clinic. In this review, an overview of GBM-on-a-chip models and their applications is reported for drug screening and discussed current challenges and potential future directions for GBM-on-a-chip models.

The roles of extracellular vesicles in gliomas: Challenge or opportunity?

Gliomas are increasingly becoming a major disease affecting human health, and current treatments are not as effective as expected. Deeper insights into glioma heterogeneity and the search for new diagnostic and therapeutic strategies appear to be urgent. Gliomas adapt to their surroundings and form a supportive tumor microenvironment (TME). Glioma cells will communicate with the surrounding cells through extracellular vesicles (EVs) carrying bioactive substances such as nucleic acids, proteins and lipids which is related to the modification to various metabolic pathways and regulation of biological behaviors, and this regulation can be bidirectional, widely existing between cells in the TME, constituting a complex network of interactions. This complex regulation can affect glioma therapy, leading to different types of resistance. Because of the feasibility of EVs isolation in various body fluids, they have a promising usage in the diagnosis and monitoring of gliomas. At the same time, the nature of EVs to cross the blood-brain barrier (BBB) confers potential for their use as drug delivery systems. In this review, we will focus on the roles and functions of EVs derived from different cellular origins in the glioma microenvironment and the intercellular regulatory networks, and explore possible clinical applications in glioma diagnosis and precision therapy.

Mass Spectrometry Advances in Analysis of Glioblastoma

Some cancers such as glioblastoma (GBM), show minimal response to medical interventions, often only capable of mitigating tumor growth or alleviating symptoms. High metabolic activity in the tumor microenvironment marked by immune responses and hypoxia, is a crucial factor driving tumor progression. The many developments in mass spectrometry (MS) over the last decades have provided a pivotal tool for studying proteins, along with their posttranslational modifications. It is known that the proteomic landscape of GBM comprises a wide range of proteins involved in cell proliferation, survival, migration, and immune evasion. Combination of MS imaging and microscopy has potential to reveal the spatial and molecular characteristics of pathological tissue sections. Moreover, integration of MS in the surgical process in form of techniques such as DESI-MS or rapid evaporative ionization MS has been shown as an effective tool for rapid measurement of metabolite profiles, providing detailed information within seconds. In immunotherapy-related research, MS plays an indispensable role in detection and targeting of cancer antigens which serve as a base for antigen-specific therapies. In this review, we aim to provide detailed information on molecular profile in GBM and to discuss recent MS advances and their clinical benefits for targeting this aggressive disease.

Impact of Age and Gender on Survival of Glioblastoma Multiforme Patients: A Multicenter Retrospective Study

BACKGROUND

Glioblastoma multiforme (GBM) poses a significant health challenge as the most common primary malignancy of the adult central nervous system. Gender- and age-related differences in GBM influence prognosis and treatment complexities. This multicenter retrospective study explores gender and age disparities in GBM patients, investigating their impact on occurrence and survival outcomes.

METHODS

This multicenter retrospective study involved GBM patients treated in Guilan Province, Iran. Patients' data, including age, gender, tumor location, and histopathological diagnosis date, was collected from medical records.

RESULTS

In a cohort of 164 GBM patients, the average age was 54.34 ± 14.16 years, with a higher prevalence among men (59.8%) and patients aged ≤ 60 years (64.6%). The tumor sites exhibited overlapping features in 68% of cases, with the frontal and temporal lobes being the most common specific locations. The mean survival was 12.88 ± 14.14 months, one-year survival of 45%, with women showing significantly higher one-year survival (60% vs. 40%) and longer mean survival (16.14 ± 17.35 vs. 10.75 ± 11.15 months). Furthermore, Patients ≤ 60 years had significantly higher one-year survival (75% vs. 35%). In subgroup analysis, women had significantly higher survival rates in patients ≤ 60 years. However, among patients over 60, women exhibited a more pronounced decline in survival rates, with no statistically significant difference between men and women in this age group.

CONCLUSION

This study highlights that both age and gender significantly affect GBM survival outcomes. Younger patients, particularly women, exhibited better survival rates, while older patients, especially women, showed poorer outcomes. These findings suggest the need to stratify treatment approaches by both age and gender to optimize care and improve survival in GBM patients. Further research is recommended to explore these associations.

Recent update on anti-tumor mechanisms of valproic acid in glioblastoma multiforme

Glioblastoma multiforme (GBM) is a malignant tumor of the brain that is considered to be incurable. Currently, surgical removal of tumors, chemotherapy with temozolomide, and radiation treatment remain established options for treatment. Nevertheless, the prognosis of those with GBM continues to be poor owing to the inherent characteristics of tumor growth and spread, as well as the resistance to treatment. To effectively deal with the present circumstances, it is vital to do extensive study to understand GBM thoroughly. The following piece provides a concise overview of the most recent advancements in using valproic acid, an antiseizure medication licensed by the FDA, for treating GBM. In this review, we outline the most recent developments of valproic acid in treating GBM, as well as its fundamental mechanisms and practical consequences. Our goal is to provide a greater understanding of the clinical use of valproic acid as a potential therapeutic agent for GBM.

Harnessing the role of aberrant cell signaling pathways in glioblastoma multiforme: a prospect towards the targeted therapy

Glioblastoma Multiforme (GBM), designated as grade IV by the World Health Organization, is the most aggressive and challenging brain tumor within the central nervous system. Around 80% of GBM patients have a poor prognosis, with a median survival of 12-15 months. Approximately 90% of GBM cases originate from normal glial cells via oncogenic processes, while the remainder arise from low-grade tumors. GBM is notorious for its heterogeneity, high recurrence rates, invasiveness, and aggressive behavior. Its malignancy is driven by increased invasive migration, proliferation, angiogenesis, and reduced apoptosis. Throughout various stages of central nervous system (CNS) development, pivotal signaling pathways, including Wnt/β-catenin, Sonic hedgehog signaling (Shh), PI3K/AKT/mTOR, Ras/Raf/MAPK/ERK, STAT3, NF-КB, TGF-β, and Notch signaling, orchestrate the growth, proliferation, differentiation, and migration of neural progenitor cells in the brain. Numerous upstream and downstream regulators within these signaling pathways have been identified as significant contributors to the development of human malignancies. Disruptions or aberrant activations in these pathways are linked to gliomagenesis, enhancing the invasiveness, progression, and aggressiveness of GBM, along with epithelial to mesenchymal transition (EMT) and the presence of glioma stem cells (GSCs). Traditional GBM treatment involves surgery, radiotherapy, and chemotherapy with Temozolomide (TMZ). However, most patients experience tumor recurrence, leading to low survival rates. This review provides an overview of the major cell signaling pathways involved in gliomagenesis. Furthermore, we explore the signaling pathways leading to therapy resistance and target key molecules within these signaling pathways, paving the way for the development of novel therapeutic approaches.

The mutated in colorectal cancer (MCC) gene can serve as a potential biomarker of glioblastoma

Introduction

The mutated in colorectal cancer (MCC) gene was initially identified as a candidate tumor suppressor gene in colorectal cancer, acting as a negative regulator of cell cycle progression. However, its functional roles in brain tumors, particularly glioblastoma, remain largely unexplored. This study reveals a significant association between MCC status and glioblastoma.

Methods

We explored MCC expression in the glioblastoma database, patient samples, and cell lines. We investigated the proliferation and migration of the cell lines in MCC gene knockdown using small interfering RNA.

Results

In vitro analyses revealed elevated protein and mRNA levels of MCC in several glioblastoma cell lines (U118MG and T98G). Silencing MCC expression via siRNA-mediated knockdown resulted in increased proliferation and migration of these cell lines. Supporting these findings, analyses of The Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA), and Genotype-Tissue Expression (GTEx) databases confirmed higher MCC expression in glioblastoma tumors than in normal brain tissue. Importantly, we observed that high MCC expression was associated with poor prognosis in glioblastoma patients, highlighting its potential role in disease progression. Additionally, this study identifies a nuclear localization of MCC in the glioblastoma cell line.

Discussion

These findings indicate that MCC expression is significantly upregulated in glioblastoma and may play a role in its pathophysiology, warranting further investigation.

Nod-like receptors: The relevant elements of glioblastoma`s prognostic puzzle

Despite considerable improvements in understanding the biology of glioblastoma (GB), it still remains the most lethal type of brain tumor in adults. The role of innate immune cells in the development of GB was recently described. In particular, the tumor-immune cell interactions are thought to be critical in enabling tumor tolerance and even protection against therapeutics. Interestingly, the GB cells express proteins belonging to the family of intracellular pattern-recognition receptors, namely the NOD-like receptors (NLRs). Their activation may trigger the formation of the inflammasome complex leading to the secretion of mature IL-1β and IL-18 and thus resulting in cell death. Intrudingly, the expression of most NLRs was found to be correlated with tumor progression and poor prognosis. We speculate that recognizing the role of NOD-like receptors in GB has the potential to improve the effectiveness of diagnostic tools and prognosis, while also encouraging the development of novel precision medicine-based therapies.

Elevated α-1,2-mannosidase MAN1C1 in glioma stem cells and its implications for immunological changes and prognosis in glioma patients

Glioblastoma multiforme (GBM) is the most aggressive type of primary brain tumor, and the presence of glioma stem cells (GSCs) has been linked to its resistance to treatments and recurrence. Additionally, aberrant glycosylation has been implicated in the aggressiveness of cancers. However, the influence and underlying mechanism of N-glycosylation on the GSC phenotype and GBM malignancy remain elusive. Here, we performed an in-silico analysis approach on publicly available datasets to examine the function of N-glycosylation-related genes in GSCs and gliomas, accompanied by a qRT-PCR validation experiment. We found that high α-1,2-mannosidase MAN1C1 is associated with immunological functions and worse survival of glioma patients. Differential gene expression analysis and qRT-PCR validation revealed that MAN1C1 is highly expressed in GSCs. Furthermore, higher MAN1C1 expression predicts worse outcomes in glioma patients. Also, MAN1C1 expression is increased in the perinecrotic region of GBM and is associated with immunological and inflammatory functions, a hallmark of the GBM mesenchymal subtype. Further analysis confirmed that MAN1C1 expression is closely associated with infiltrating immune cells and disrupted immune response in the GBM microenvironment. These suggest that MAN1C1 is a potential biomarker for gliomas and may be important as an immunotherapeutic target for GBM.

Leveraging multi-omics data to infer regulators of mRNA 3' end processing in glioblastoma

Alterations in mRNA 3' end processing and polyadenylation are widely implicated in the biology of many cancer types, including glioblastoma (GBM), one the most aggressive tumor types. Although several RNA-binding proteins (RBPs) responsible for alternative polyadenylation (APA) were identified from functional studies in cell lines, their contribution to the APA landscape in tumors in vivo was not thoroughly addressed. In this study we analyzed a large RNA-seq data set of glioblastoma (GBM) samples from The Cancer Genome Atlas (TCGA) to identify APA patterns differentiating the main molecular subtypes of GBM. We superimposed these to RBP footprinting data and to APA events occurring upon depletion of individual RBPs from a large panel tested by the ENCODE Consortium. Our analysis revealed 22 highly concordant and statistically significant RBP-APA associations, whereby changes in RBP expression were accompanied by APA in both TCGA and ENCODE datasets. Among these, we found a previously unknown PTBP1-regulated APA event in the PRRC2B gene and an HNRNPU-regulated event in the SC5D gene. Both of these were further supported by RNA-sequencing data of paired tumor center-periphery GBM samples obtained at the University Hospital of Basel. In addition, we validated the regulation of APA in PRRC2B by PTBP1 in siRNA-knockdown and overexpression experiments followed by RNA-sequencing in two glioblastoma cell lines. The transcriptome analysis workflow that we present here enables the identification of concordant RBP-APA associations in cancers.

Role of renin angiotensin system inhibitors and metformin in Glioblastoma Therapy: a review

Glioblastoma multiforme (GBM) is a highly aggressive and incurable disease accounting for about 10,000 deaths in the USA each year. Despite the current treatment approach which includes surgery with chemotherapy and radiation therapy, there remains a high prevalence of recurrence. Notable improvements have been observed in persons receiving concurrent antihypertensive drugs such as renin angiotensin inhibitors (RAS) or the antidiabetic drug metformin with standard therapy. Anti-tumoral effects of RAS inhibitors and metformin have been observed in in vitro and in vivo studies. Although clinical trials have shown mixed results, the potential for the use of RAS inhibitors and metformin as adjuvant GBM therapy remains promising. Nevertheless, evidence suggest that these drugs exert multimodal antitumor actions; by particularly targeting several cancer hallmarks. In this review, we highlight the results of clinical studies using multidrug cocktails containing RAS inhibitors and or metformin added to standard therapy for GBM. In addition, we highlight the possible molecular mechanisms by which these repurposed drugs with an excellent safety profile might elicit their anti-tumoral effects. RAS inhibition elicits anti-inflammatory, anti-angiogenic, and immune sensitivity effects in GBM. However, metformin promotes anti-migratory, anti-proliferative and pro-apoptotic effects mainly through the activation of AMP-activated protein kinase. Also, we discussed metformin's potential in targeting both GBM cells as well as GBM associated-stem cells. Finally, we summarize a few drug interactions that may cause an additive or antagonistic effect that may lead to adverse effects and influence treatment outcome.

A systematic computational analysis of the endosomal recycling pathway in glioblastoma

Glioblastoma (GBM) is the most common and aggressive brain cancer in adults. The standard treatment is brutal and has changed little in 20 years, and more than 85% of patients will die within two years of their diagnosis. There is thus an urgent need to identify new drug targets and develop novel therapeutic strategies to increase survival and improve quality of life. Using publicly available genomics, transcriptomics and proteomics datasets, we compared the expression of endosomal recycling pathway regulators in non-tumour brain tissue with their expression in GBM. We found that key regulators of this pathway are dysregulated in GBM and their expression levels can be linked to survival outcomes. Further analysis of the differentially expressed endosomal recycling regulators allowed us to generate an 8-gene prognostic signature that can distinguish low-risk from high-risk GBM and potentially identify tumours that may benefit from treatment with endosomal recycling inhibitors. This study presents the first systematic analysis of the endosomal recycling pathway in glioblastoma and suggests it could be a promising target for the development of novel therapies and therapeutic strategies to improve outcomes for patients.

A prognostic matrix gene expression signature defines functional glioblastoma phenotypes and niches

Background

Interactions among tumor, immune, and vascular niches play major roles in driving glioblastoma (GBM) malignancy and treatment responses. The composition, heterogeneity, and localization of extracellular core matrix proteins (CMPs) that mediate such interactions, however, are not well understood.

Methods

Here, through computational genomics and proteomics approaches, we analyzed the functional and clinical relevance of CMP expression in GBM at bulk, single cell, and spatial anatomical resolution.

Results

We identified genes encoding CMPs whose expression levels categorize GBM tumors into CMP expression-high (M-H) and CMP expression-low (M-L) groups. CMP enrichment is associated with worse patient survival, specific driver oncogenic alterations, mesenchymal state, infiltration of pro-tumor immune cells, and immune checkpoint gene expression. Anatomical and single-cell transcriptome analyses indicate that matrisome gene expression is enriched in vascular and leading edge/infiltrative niches that are known to harbor glioma stem cells driving GBM progression. Finally, we identified a 17-gene CMP expression signature, termed Matrisome 17 (M17) signature that further refines the prognostic value of CMP genes. The M17 signature is a significantly stronger prognostic factor compared to MGMT promoter methylation status as well as canonical subtypes, and importantly, potentially predicts responses to PD1 blockade.

Conclusion

The matrisome gene expression signature provides a robust stratification of GBM patients by survival and potential biomarkers of functionally relevant GBM niches that can mediate mesenchymal-immune cross talk. Patient stratification based on matrisome profiles can contribute to selection and optimization of treatment strategies.

Revolutionizing Brain Tumor Care: Emerging Technologies and Strategies

Glioblastoma multiforme (GBM) is one of the most aggressive forms of brain tumor, characterized by a daunting prognosis with a life expectancy hovering around 12-16 months. Despite a century of relentless research, only a select few drugs have received approval for brain tumor treatment, largely due to the formidable barrier posed by the blood-brain barrier. The current standard of care involves a multifaceted approach combining surgery, irradiation, and chemotherapy. However, recurrence often occurs within months despite these interventions. The formidable challenges of drug delivery to the brain and overcoming therapeutic resistance have become focal points in the treatment of brain tumors and are deemed essential to overcoming tumor recurrence. In recent years, a promising wave of advanced treatments has emerged, offering a glimpse of hope to overcome the limitations of existing therapies. This review aims to highlight cutting-edge technologies in the current and ongoing stages of development, providing patients with valuable insights to guide their choices in brain tumor treatment.

Rapid detection of IDH mutations in gliomas by intraoperative mass spectrometry

The development and performance of two mass spectrometry (MS) workflows for the intraoperative diagnosis of isocitrate dehydrogenase (IDH) mutations in glioma is implemented by independent teams at Mayo Clinic, Jacksonville, and Huashan Hospital, Shanghai. The infiltrative nature of gliomas makes rapid diagnosis necessary to guide the extent of surgical resection of central nervous system (CNS) tumors. The combination of tissue biopsy and MS analysis used here satisfies this requirement. The key feature of both described methods is the use of tandem MS to measure the oncometabolite 2-hydroxyglutarate (2HG) relative to endogenous glutamate (Glu) to characterize the presence of mutant tumor. The experiments i) provide IDH mutation status for individual patients and ii) demonstrate a strong correlation of 2HG signals with tumor infiltration. The measured ratio of 2HG to Glu correlates with IDH-mutant (IDH-mut) glioma (P < 0.0001) in the tumor core data of both teams. Despite using different ionization methods and different mass spectrometers, comparable performance in determining IDH mutations from core tumor biopsies was achieved with sensitivities, specificities, and accuracies all at 100%. None of the 31 patients at Mayo Clinic or the 74 patients at Huashan Hospital were misclassified when analyzing tumor core biopsies. Robustness of the methodology was evaluated by postoperative re-examination of samples. Both teams noted the presence of high concentrations of 2HG at surgical margins, supporting future use of intraoperative MS to monitor for clean surgical margins. The power of MS diagnostics is shown in resolving contradictory clinical features, e.g., in distinguishing gliosis from IDH-mut glioma.

Drug-Induced Reorganisation of Lipid Metabolism Limits the Therapeutic Efficacy of Ponatinib in Glioma Stem Cells

The standard of care for glioblastoma (GBM) involves surgery followed by adjuvant radio- and chemotherapy, but often within months, patients relapse, and this has been linked to glioma stem cells (GSCs), self-renewing cells with increased therapy resistance. The identification of the epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor (PDGFR) as key players in gliomagenesis inspired the development of inhibitors targeting these tyrosine kinases (TKIs). However, results from clinical trials testing TKIs have been disappointing, and while the role of GSCs in conventional therapy resistance has been extensively studied, less is known about resistance of GSCs to TKIs. In this study, we have used compartmentalised proteomics to analyse the adaptive response of GSCs to ponatinib, a TKI with activity against PDGFR. The analysis of differentially expressed proteins revealed that GSCs respond to ponatinib by broadly rewiring lipid metabolism, involving fatty acid beta-oxidation, cholesterol synthesis, and sphingolipid degradation. Inhibiting each of these metabolic pathways overcame ponatinib adaptation of GSCs, but interrogation of patient data revealed sphingolipid degradation as the most relevant pathway in GBM. Our data highlight that targeting lipid metabolism, and particularly sphingolipid degradation in combinatorial therapies, could improve the outcome of TKI therapies using ponatinib in GBM.

Targeting inflammation in glioblastoma: An updated review from pathophysiology to novel therapeutic approaches

Glioblastoma (GBM) is a highly aggressive primary malignant brain tumor with a dismal prognosis despite current treatment strategies. Inflammation plays an essential role in GBM pathophysiology, contributing to tumor growth, invasion, immunosuppression, and angiogenesis. As a result, pharmacological intervention with anti-inflammatory drugs has been used as a potential approach for the management of GBM. To provide an overview of the current understanding of GBM pathophysiology, potential therapeutic applications of anti-inflammatory drugs in GBM, conventional treatments of glioblastoma and emerging therapeutic approaches currently under investigation. A narrative review was carried out, scanning publications from 2000 to 2023 on PubMed and Google Scholar. The search was not guided by a set research question or a specific search method but rather focused on the area of interest. Conventional treatments such as surgery, radiotherapy, and chemotherapy have shown some benefits, but their effectiveness is limited by various factors such as tumor heterogeneity and resistance.

PPAR-γ agonists reactivate the ALDOC-NR2F1 axis to enhance sensitivity to temozolomide and suppress glioblastoma progression

Glioblastoma (GBM) is a type of brain cancer categorized as a high-grade glioma. GBM is characterized by limited treatment options, low patient survival rates, and abnormal serotonin metabolism. Previous studies have investigated the tumor suppressor function of aldolase C (ALDOC), a glycolytic enzyme in GBM. However, it is unclear how ALDOC regulates production of serotonin and its associated receptors, HTRs. In this study, we analyzed ALDOC mRNA levels and methylation status using sequencing data and in silico datasets. Furthermore, we investigated pathways, phenotypes, and drug effects using cell and mouse models. Our results suggest that loss of ALDOC function in GBM promotes tumor cell invasion and migration. We observed that hypermethylation, which results in loss of ALDOC expression, is associated with serotonin hypersecretion and the inhibition of PPAR-γ signaling. Using several omics datasets, we present evidence that ALDOC regulates serotonin levels and safeguards PPAR-γ against serotonin metabolism mediated by 5-HT, which leads to a reduction in PPAR-γ expression. PPAR-γ activation inhibits serotonin release by HTR and diminishes GBM tumor growth in our cellular and animal models. Importantly, research has demonstrated that PPAR-γ agonists prolong animal survival rates and increase the efficacy of temozolomide in an orthotopic brain model of GBM. The relationship and function of the ALDOC-PPAR-γ axis could serve as a potential prognostic indicator. Furthermore, PPAR-γ agonists offer a new treatment alternative for glioblastoma multiforme (GBM).

Reprogramming Tumor-Associated Macrophage Using Nanocarriers: New Perspectives to Halt Cancer Progression

Cancer remains a significant challenge for public healthcare systems worldwide. Within the realm of cancer treatment, considerable attention is focused on understanding the tumor microenvironment (TME)-the complex network of non-cancerous elements surrounding the tumor. Among the cells in TME, tumor-associated macrophages (TAMs) play a central role, traditionally categorized as pro-inflammatory M1 macrophages or anti-inflammatory M2 macrophages. Within the TME, M2-like TAMs can create a protective environment conducive to tumor growth and progression. These TAMs secrete a range of factors and molecules that facilitate tumor angiogenesis, increased vascular permeability, chemoresistance, and metastasis. In response to this challenge, efforts are underway to develop adjuvant therapy options aimed at reprogramming TAMs from the M2 to the anti-tumor M1 phenotype. Such reprogramming holds promise for suppressing tumor growth, alleviating chemoresistance, and impeding metastasis. Nanotechnology has enabled the development of nanoformulations that may soon offer healthcare providers the tools to achieve targeted drug delivery, controlled drug release within the TME for TAM reprogramming and reduce drug-related adverse events. In this review, we have synthesized the latest data on TAM polarization in response to TME factors, highlighted the pathological effects of TAMs, and provided insights into existing nanotechnologies aimed at TAM reprogramming and depletion.

Identification and classification of glioma subtypes based on RNA-binding proteins

BACKGROUND

Glioma is a common and aggressive primary malignant cancer known for its high morbidity, mortality, and recurrence rates. Despite this, treatment options for glioma are currently restricted. The dysregulation of RBPs has been linked to the advancement of several types of cancer, but their precise role in glioma evolution is still not fully understood. This study sought to investigate how RBPs may impact the development and prognosis of glioma, with potential implications for prognosis and therapy.

METHODS

RNA-seq profiles of glioma and corresponding clinical data from the CGGA database were initially collected for analysis. Unsupervised clustering was utilized to identify crucial tumor subtypes in glioma development. Subsequent time-series analysis and MS model were employed to track the progression of these identified subtypes. RBPs playing a significant role in glioma progression were then pinpointed using WGCNA and Lasso Cox regression models. Functional analysis of these key RBP-related genes was conducted through GSEA. Additionally, the CIBERSORT algorithm was utilized to estimate immune infiltrating cells, while the STRING database was consulted to uncover potential mechanisms of the identified biomarkers.

RESULTS

Six tumor subgroups were identified and found to be highly homogeneous within each subgroup. The progression stages of these tumor subgroups were determined using time-series analysis and a MS model. Through WGCNA, Lasso Cox, and multivariate Cox regression analysis, it was confirmed that BCLAF1 is correlated with survival in glioma patients and is closely linked to glioma progression. Functional annotation suggests that BCLAF1 may impact glioma progression by influencing RNA splicing, which in turn affects the cell cycle, Wnt signaling pathway, and other cancer development pathways.

CONCLUSIONS

The study initially identified six subtypes of glioma progression and assessed their malignancy ranking. Furthermore, it was determined that BCLAF1 could serve as an RBP-related prognostic marker, offering significant implications for the clinical diagnosis and personalized treatment of glioma.

Expression of molecular markers and synergistic anticancer effects of chemotherapy with antimicrobial peptides on glioblastoma cells

OBJECTIVE

Glioblastoma multiforme (GBM) is the most aggressive and fatal malignant primary brain tumor. The enhancement of the survival rate for glioma patients remains limited, even with the utilization of a combined treatment approach involving surgery, radiotherapy, and chemotherapy. This study was designed to assess the expression of IDH1, TP53, EGFR, Ki-67, GFAP, H3K27M, MGMT, VEGF, NOS, CD99, and ATRX in glioblastoma tissue from 11 patients. We investigated the anticancer impact and combined effects of cathelicidin (LL-37), protegrin-1 (PG-1), with chemotherapy-temozolomide (TMZ), doxorubicin (DOX), carboplatin (CB), cisplatin (CPL), and etoposide (ETO) in primary GBM cells. In addition, we examined the effect of LL-37, PG-1 on normal human fibroblasts and in the C6/Wistar rat intracerebral glioma model.

METHODS

For this study, 11 cases of glioblastoma were evaluated immunohistochemically for IDH1, TP53, EGFR, Ki-67, GFAP, H3K27M, MGMT, VEGF, NOS, CD99, and ATRX. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to study cells viability and to determine cytotoxic effects of LL-37, PG-1 and their combination with chemotherapy in primary GBM cells. Synergism or antagonism was determined using combination index (CI) method. Finally, we established C6 glioblastoma model in Wistar rats to investigate the antitumor activity.

RESULTS

Peptides showed a strong cytotoxic effect on primary GBM cells in the MTT test (IC50 2-16 and 1-32 μM) compared to chemotherapy. The dual-drug combinations of LL-37 + DOX, LL-37 + CB (CI 0.46-0.75) and PG-1 + DOX, PG-1 + CB, PG-1 + TMZ (CI 0.11-0.77), demonstrated a synergism in primary GBM cells. In rat C6 intracerebral GBM model, survival of rats in experimental group (66.75 ± 12.6 days) was prolonged compared with that in control cohort (26.2 ± 2.66 days, p = 0.0008). After LL-37 treatment, experimental group rats showed significantly lower tumor volumes (31.00 ± 8.8 mm3) and weight (49.4 ± 13.3 mg) compared with control group rats (153.8 ± 43.53 mg, p = 0.038; 82.50 ± 7.60 mm3, respectively).

CONCLUSIONS

The combination of antimicrobial peptides and chemical drugs enhances the cytotoxicity of chemotherapy and exerts synergistic antitumor effects in primary GBM cells. Moreover, in vivo study provided the first evidence that LL-37 could effectively inhibit brain tumor growth in rat C6 intracerebral GBM model. These results suggested a significant strategy for proposing a promising therapy for the treatment of GBM.

Zika Virus: A Neurotropic Warrior against High-Grade Gliomas-Unveiling Its Potential for Oncolytic Virotherapy

Gliomas account for approximately 75-80% of all malignant primary tumors in the central nervous system (CNS), with glioblastoma multiforme (GBM) considered the deadliest. Despite aggressive treatment involving a combination of chemotherapy, radiotherapy, and surgical intervention, patients with GBM have limited survival rates of 2 to 5 years, accompanied by a significant decline in their quality of life. In recent years, novel management strategies have emerged, such as immunotherapy, which includes the development of vaccines or T cells with chimeric antigen receptors, and oncolytic virotherapy (OVT), wherein wild type (WT) or genetically modified viruses are utilized to selectively lyse tumor cells. In vitro and in vivo studies have shown that the Zika virus (ZIKV) can infect glioma cells and induce a robust oncolytic activity. Consequently, interest in exploring this virus as a potential oncolytic virus (OV) for high-grade gliomas has surged. Given that ZIKV actively circulates in Colombia, evaluating its neurotropic and oncolytic capabilities holds considerable national and international importance, as it may emerge as an alternative for treating highly complex gliomas. Therefore, this literature review outlines the generalities of GBM, the factors determining ZIKV's specific tropism for nervous tissue, and its oncolytic capacity. Additionally, we briefly present the progress in preclinical studies supporting the use of ZIKV as an OVT for gliomas.

Cerebrospinal Fluid Liquid Biopsies in the Evaluation of Adult Gliomas

PURPOSE OF REVIEW

This review aims to discuss recent research regarding the biomolecules explored in liquid biopsies and their potential clinical uses for adult-type diffuse gliomas.

RECENT FINDINGS

Evaluation of tumor biomolecules via cerebrospinal fluid (CSF) is an emerging technology in neuro-oncology. Studies to date have already identified various circulating tumor DNA, extracellular vesicle, micro-messenger RNA and protein biomarkers of interest. These biomarkers show potential to assist in multiple avenues of central nervous system (CNS) tumor evaluation, including tumor differentiation and diagnosis, treatment selection, response assessment, detection of tumor progression, and prognosis. In addition, CSF liquid biopsies have the potential to better characterize tumor heterogeneity compared to conventional tissue collection and CNS imaging. Current imaging modalities are not sufficient to establish a definitive glioma diagnosis and repeated tissue sampling via conventional biopsy is risky, therefore, there is a great need to improve non-invasive and minimally invasive sampling methods. CSF liquid biopsies represent a promising, minimally invasive adjunct to current approaches which can provide diagnostic and prognostic information as well as aid in response assessment.

Uncovering the subtype-specific disease module and the development of drug response prediction models for glioma

The poor prognosis of glioma patients brought attention to the need for effective therapeutic approaches for precision therapy. Here, we deployed algorithms relying on network medicine and artificial intelligence to design the framework for subtype-specific target identification and drug response prediction in glioma. We identified the driver mutations that were differentially expressed in each subtype of lower-grade glioma and glioblastoma multiforme and were linked to cancer-specific processes. Driver mutations that were differentially expressed were also subjected to subtype-specific disease module identification. The drugs from the drug bank database were retrieved to target these disease modules. However, the efficacy of anticancer drugs depends on the molecular profile of the cancer and varies among cancer patients due to intratumor heterogeneity. Hence, we developed a deep-learning-based drug response prediction framework using the experimental drug screening data. Models for 30 drugs that can target the disease module were developed, where drug response measured by IC50 was considered a response and gene expression and mutation data were considered predictor variables. The model construction consists of three steps: feature selection, data integration, and classification. We observed the consistent performance of the models in training, test, and validation datasets. Drug responses were predicted for particular cell lines derived from distinct subtypes of gliomas. We found that subtypes of gliomas respond differently to the drug, highlighting the importance of subtype-specific drug response prediction. Therefore, the development of personalized therapy by integrating network medicine and a deep learning-based approach can lead to cancer-specific treatment and improved patient care.

The impact of MEIS1 TALE homeodomain transcription factor knockdown on glioma stem cell growth

Myeloid ecotropic virus insertion site 1 (MEIS1) is a HOX co-factor necessary for organ development and normal hematopoiesis. Recently, MEIS1 has been linked to the development and progression of various cancers. However, its role in gliomagenesis particularly on glioma stem cells (GSCs) remains unclear. Here, we demonstrate that MEIS1 is highly upregulated in GSCs compared to normal, and glioma cells and to its differentiated counterparts. Inhibition of MEIS1 expression by shRNA significantly reduced GSC growth in both in vitro and in vivo experiments. On the other hand, integrated transcriptomics analyses of glioma datasets revealed that MEIS1 expression is correlated to cell cycle-related genes. Clinical data analysis revealed that MEIS1 expression is elevated in high-grade gliomas, and patients with high MEIS1 levels have poorer overall survival outcomes. The findings suggest that MEIS1 is a prognostic biomarker for glioma patients and a possible target for developing novel therapeutic strategies against GBM.

Glioblastoma: An Update in Pathology, Molecular Mechanisms and Biomarkers

Glioblastoma multiforme (GBM) is the most common and malignant type of primary brain tumor in adults. Despite important advances in understanding the molecular pathogenesis and biology of this tumor in the past decade, the prognosis for GBM patients remains poor. GBM is characterized by aggressive biological behavior and high degrees of inter-tumor and intra-tumor heterogeneity. Increased understanding of the molecular and cellular heterogeneity of GBM may not only help more accurately define specific subgroups for precise diagnosis but also lay the groundwork for the successful implementation of targeted therapy. Herein, we systematically review the key achievements in the understanding of GBM molecular pathogenesis, mechanisms, and biomarkers in the past decade. We discuss the advances in the molecular pathology of GBM, including genetics, epigenetics, transcriptomics, and signaling pathways. We also review the molecular biomarkers that have potential clinical roles. Finally, new strategies, current challenges, and future directions for discovering new biomarkers and therapeutic targets for GBM will be discussed.

Therapeutic Hypothermia in Treating Glioblastoma: A Review

Glioblastoma (GBM) is the most commonly occurring of all malignant central nervous system (CNS) tumors in adults. Considering the low median survival of only ∼15 months and poor prognosis in GBM patients, despite surgical resection with adjuvant radiation and chemotherapy, it is vital to seek brand new and innovative treatment in combination with already existing methods. Hypothermia participates in many metabolic pathways, inflammatory responses, and apoptotic processes, while also promoting the integrity of neurons. Following the successful application of therapeutic hypothermia across a spectrum of disorders such as traumatic CNS injury, cardiac arrest, and epilepsy, several clinical trials have set to evaluate the potency of hypothermia in treating a variety of cancers, including breast and ovaries cancer. In regard to primary neoplasms and more specifically, GBM, hypothermia has recently shown promising results as an auxiliary treatment, reinforcing chemotherapy's efficacy. In this review, we discuss the recent advances in utilizing hypothermia as treatment for GBM and other cancers.

Cellular signaling in glioblastoma: A molecular and clinical perspective

Glioblastoma multiforme (GBM) is the most aggressive brain tumor with an average life expectancy of less than 15 months. Such high patient mortality in GBM is pertaining to the presence of clinical and molecular heterogeneity attributed to various genetic and epigenetic alterations. Such alterations in critically important signaling pathways are attributed to aberrant gene signaling. Different subclasses of GBM show predominance of different genetic alterations and therefore, understanding the complex signaling pathways and their key molecular components in different subclasses of GBM is extremely important with respect to clinical management. In this book chapter, we summarize the common and important signaling pathways that play a significant role in different subclasses and discuss their therapeutic targeting approaches in terms of preclinical studies and clinical trials.

Aberrant MET Receptor Tyrosine Kinase Signaling in Glioblastoma: Targeted Therapy and Future Directions

Brain tumors represent a heterogeneous group of neoplasms characterized by a high degree of aggressiveness and a poor prognosis. Despite recent therapeutic advances, the treatment of brain tumors, including glioblastoma (GBM), an aggressive primary brain tumor associated with poor prognosis and resistance to therapy, remains a significant challenge. Receptor tyrosine kinases (RTKs) are critical during development and in adulthood. Dysregulation of RTKs through activating mutations and gene amplification contributes to many human cancers and provides attractive therapeutic targets for treatment. Under physiological conditions, the Met RTK, the hepatocyte growth factor/scatter factor (HGF/SF) receptor, promotes fundamental signaling cascades that modulate epithelial-to-mesenchymal transition (EMT) involved in tissue repair and embryogenesis. In cancer, increased Met activity promotes tumor growth and metastasis by providing signals for proliferation, survival, and migration/invasion. Recent clinical genomic studies have unveiled multiple mechanisms by which MET is genetically altered in GBM, including focal amplification, chromosomal rearrangements generating gene fusions, and a splicing variant mutation (exon 14 skipping, METex14del). Notably, MET overexpression contributes to chemotherapy resistance in GBM by promoting the survival of cancer stem-like cells. This is linked to distinctive Met-induced pathways, such as the upregulation of DNA repair mechanisms, which can protect tumor cells from the cytotoxic effects of chemotherapy. The development of MET-targeted therapies represents a major step forward in the treatment of brain tumours. Preclinical studies have shown that MET-targeted therapies (monoclonal antibodies or small molecule inhibitors) can suppress growth and invasion, enhancing the efficacy of conventional therapies. Early-phase clinical trials have demonstrated promising results with MET-targeted therapies in improving overall survival for patients with recurrent GBM. However, challenges remain, including the need for patient stratification, the optimization of treatment regimens, and the identification of mechanisms of resistance. This review aims to highlight the current understanding of mechanisms underlying MET dysregulation in GBM. In addition, it will focus on the ongoing preclinical and clinical assessment of therapies targeting MET dysregulation in GBM.

Emerging Lipid Targets in Glioblastoma

GBM accounts for most of the fatal brain cancer cases, making it one of the deadliest tumor types. GBM is characterized by severe progression and poor prognosis with a short survival upon conventional chemo- and radiotherapy. In order to improve therapeutic efficiency, considerable efforts have been made to target various features of GBM. One of the targetable features of GBM is the rewired lipid metabolism that contributes to the tumor's aggressive growth and penetration into the surrounding brain tissue. Lipid reprogramming allows GBM to acquire survival, proliferation, and invasion benefits as well as supportive modulation of the tumor microenvironment. Several attempts have been made to find novel therapeutic approaches by exploiting the lipid metabolic reprogramming in GBM. In recent studies, various components of de novo lipogenesis, fatty acid oxidation, lipid uptake, and prostaglandin synthesis have been considered promising targets in GBM. Emerging data also suggest a significant role hence therapeutic potential of the endocannabinoid metabolic pathway in GBM. Here we review the lipid-related GBM characteristics in detail and highlight specific targets with their potential therapeutic use in novel antitumor approaches.

Impact of hypoxia on the molecular content of glioblastoma-derived exosomes

Hypoxia is a pathologic condition characterized by a tissue oxygen deficiency due to either decreased oxygen intake from outside and/or disruption of oxygen utilization in cells. This condition may arise when the oxygen demand exceeds its supply or the partial pressure of oxygen is below 10 mmHg. This situation poses a significant problem for glioblastoma (GBM) patients as it can activate angiogenesis, increase invasiveness and metastatic risk, prolong tumor survival, and suppress anti-tumor immunity, making hypoxic cells resistant to radiotherapy and chemotherapy. Low oxygen levels in tumors can cause severe cellular changes that can affect the release of extracellular vesicles (EVs), especially exosomes (EXOs), altering their proteomic profile both qualitatively and quantitatively. EXOs represent an adaptive response to hypoxic stress; therefore, they can be used to determine oxygen levels in cancer and assess its aggressiveness. They not only release signaling molecules to attract cells that promote the formation of small vessel walls but also send signals to other tumor cells that trigger their migration, which in turn plays a crucial role in the formation of metastases under hypoxia. This review investigates how the molecular profile of GBM-derived exosomes changes under hypoxic conditions, offering future possibilities for noninvasive diagnosis and monitoring of brain tumor patients.

Targeted Glioma Therapy-Clinical Trials and Future Directions

Glioblastoma multiforme (GBM) is the most common type of glioma, with a median survival of 14.6 months post-diagnosis. Understanding the molecular profile of such tumors allowed the development of specific targeted therapies toward GBM, with a major role attributed to tyrosine kinase receptor inhibitors and immune checkpoint inhibitors. Targeted therapeutics are drugs that work by specific binding to GBM-specific or overexpressed markers on the tumor cellular surface and therefore contain a recognition moiety linked to a cytotoxic agent, which produces an antiproliferative effect. In this review, we have summarized the available information on the targeted therapeutics used in clinical trials of GBM and summarized current obstacles and advances in targeted therapy concerning specific targets present in GBM tumor cells, outlined efficacy endpoints for major classes of investigational drugs, and discussed promising strategies towards an increase in drug efficacy in GBM.

Comparative Analysis of the Prognostic Significance of IDH,TERT, EGFR and MGMT Status in Patients with Adult Non-H3-Altered Grade 4 Gliomas: A Prospective Cohort Study

INTRODUCTION

Gliomas continue to have a dismal prognosis. A myriad of genetic alterations has been described in this subset of tumors over the last decades. The integrative interpretation of the biomarker constellation for individual patients remains unclear. This study aims to evaluate the impact of some known genetic factors as prognostic biomarkers in grade 4 gliomas.

METHODS

Adult non-H3-altered grade 4 gliomas who underwent maximal safe resection accompanied by adjuvant therapy were successively enrolled since January 2019 till January 2021. Patient data were documented preoperatively and during the follow-up visits. The genetic profiling of the tumors included Isocitrate Dehydrogenase (IDH)-1 and IDH-2 mutation, MGMT promoter methylation rate, EGFR gene amplification and telomerase reverse transcriptase gene promoter (TERTp) mutation.

RESULTS

Mean Overall survival (OS) and Progression-free survival (PFS) were 14.45 ± 5.13 months (3-24 months) and 10.66 ± 4.87 months respectively. TERTp-mutant group had a significantly lower OS (10.9 vs. 15.9) and PFS (6.9 vs. 12.3) than TERTp wildtype group. In the TERT-mutant group, those with concomitant IDH wildtype tumor had higher OS and PFS, comparable to those with both TERTp and IDH wildtype tumors. In multivariate analysis, IDH mutation and TERTp wildtype status were predictive of longer OS and PFS. While IDH and absence of TERTp mutation were associated with KPS > 80 across the follow-ups, their predictive values were inferior to preoperative KPS scores.

CONCLUSIONS

TERTp mutation and IDH-wildtype status were associated with worse OS and PFS and lower follow-up KPS score in surgically resected gliomas, while MGMT and EGFR status did not have considerable prognostic value in this study.

Glycation Interferes with the Expression of Sialyltransferases and Leads to Increased Polysialylation in Glioblastoma Cells

Glioblastoma (GBM) is a highly aggressive brain tumor that often utilizes aerobic glycolysis for energy production (Warburg effect), resulting in increased methylglyoxal (MGO) production. MGO, a reactive dicarbonyl compound, causes protein alterations and cellular dysfunction via glycation. In this study, we investigated the effect of glycation on sialylation, a common post-translational modification implicated in cancer. Our experiments using glioma cell lines, human astrocytes (hA), and primary glioma samples revealed different gene expressions of sialyltransferases among cells, highlighting the complexity of the system. Glycation has a differential effect on sialyltransferase expression, upregulating ST8SIA4 in the LN229 and U251 cell lines and decreasing the expression in normal hA. Subsequently, polysialylation increased in the LN229 and U251 cell lines and decreased in hA. This increase in polysialylation could lead to a more aggressive phenotype due to its involvement in cancer hallmark processes such as immune evasion, resistance to apoptosis, and enhancing invasion. Our findings provide insights into the mechanisms underlying GBM aggressiveness and suggest that targeting glycation and sialylation could be a potential therapeutic strategy.

Unveiling the Influence of Tumor Microenvironment and Spatial Heterogeneity on Temozolomide Resistance in Glioblastoma Using an Advanced Human In Vitro Model of the Blood-Brain Barrier and Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain cancer in adults with a dismal prognosis. Temozolomide (TMZ) is the first-in-line chemotherapeutic; however, resistance is frequent and multifactorial. While many molecular and genetic factors have been linked to TMZ resistance, the role of the solid tumor morphology and the tumor microenvironment, particularly the blood-brain barrier (BBB), is unknown. Here, the authors investigate these using a complex in vitro model for GBM and its surrounding BBB. The model recapitulates important clinical features such as a dense tumor core with tumor cells that invade along the perivascular space; and a perfusable BBB with a physiological permeability and morphology that is altered in the presence of a tumor spheroid. It is demonstrated that TMZ sensitivity decreases with increasing cancer cell spatial organization, and that the BBB can contribute to TMZ resistance. Proteomic analysis with next-generation low volume sample workflows of these cultured microtissues revealed potential clinically relevant proteins involved in tumor aggressiveness and TMZ resistance, demonstrating the utility of complex in vitro models for interrogating the tumor microenvironment and therapy validation.

Identification and validation of DNA methylation-driven gene PCDHB4 as a novel tumor suppressor for glioblastoma diagnosis and prognosis

Aberrant DNA methylation is a critical regulator of gene expression in the development and progression of glioblastoma (GBM). However, the impact of methylation-driven gene PCDHB4 changes on GBM occurrence and progression remains unclear. Therefore, this study aimed to identify the PCDHB4 gene for early diagnosis and prognostic evaluation and clarify its functional role in GBM. Methylation-driven gene PCDHB4 was selected for GBM using the multi-omics integration method based on publicly available data sets. The diagnostic capabilities of PCDHB4 methylation and 5-hydroxymethylcytosines were validated in tissue and blood cell-free DNA (cfDNA) samples, respectively. Combined survival analysis of PCDHB4 methylation and immune infiltration cells evaluated the prognostic predictive performance of GBM patients. We identified that the PCDHB4 gene achieved high discriminative capabilities for GBM and normal tissues with an area under the curve value of 0.941. PCDHB4 hypermethylation was observed in cfDNA blood samples from GBM patients. Compared with GBM patients with PCDHB4 hypermethylation level, patients with PCDHB4 hypomethylation level had significantly poorer overall survival (p = 0.035). In addition, GBM patients with PCDHB4 hypermethylation and high infiltration of CD4+ T cell activation level had a favorable survival (p = 0.026). Moreover, we demonstrated that mRNA expression of PCDHB4 was downregulated in GBM tissues and upregulated in GBM cell lines with PCDHB4 demethylation, and PCDHB4 overexpression inhibited GBM cell proliferation and migration. In summary, we discovered a novel methylation-driven gene PCDHB4 for the diagnosis and prognosis of GBM and demonstrated that PCDHB4 is a tumor suppressor in vitro experiments.

Molecular Targeted Therapies in Glioblastoma Multiforme: A Systematic Overview of Global Trends and Findings

This systematic review assesses current molecular targeted therapies for glioblastoma multiforme (GBM), a challenging condition with limited treatment options. Using PRISMA methodology, 166 eligible studies, involving 2526 patients (61.49% male, 38.51% female, with a male-to-female ratio of 1.59/1), were analyzed. In laboratory studies, 52.52% primarily used human glioblastoma cell cultures (HCC), and 43.17% employed animal samples (mainly mice). Clinical participants ranged from 18 to 100 years, with 60.2% using combined therapies and 39.8% monotherapies. Mechanistic categories included Protein Kinase Phosphorylation (41.6%), Cell Cycle-Related Mechanisms (18.1%), Microenvironmental Targets (19.9%), Immunological Targets (4.2%), and Other Mechanisms (16.3%). Key molecular targets included Epidermal Growth Factor Receptor (EGFR) (10.8%), Mammalian Target of Rapamycin (mTOR) (7.2%), Vascular Endothelial Growth Factor (VEGF) (6.6%), and Mitogen-Activated Protein Kinase (MEK) (5.4%). This review provides a comprehensive assessment of molecular therapies for GBM, highlighting their varied efficacy in clinical and laboratory settings, ultimately impacting overall and progression-free survival in GBM management.

Identification of T-cell exhaustion-related gene signature for predicting prognosis in glioblastoma multiforme

Glioblastoma multiforme (GBM) is a highly malignant primary brain tumour with a poor prognosis in adults. Identifying biomarkers that can aid in the molecular classification and risk stratification of GBM is critical. Here, we conducted a transcriptional profiling analysis of T-cell immunity in the tumour microenvironment of GBM patients and identified two novel T cell exhaustion (TEX)-related GBM subtypes (termed TEX-C1 and TEX-C2) using the consensus clustering. Our multi-omics analysis revealed distinct immunological, molecular and clinical characteristics for these two subtypes. Specifically, the TEX-C1 subtype had higher infiltration levels of immune cells and expressed higher levels of immune checkpoint molecules than the TEX-C2 subtype. Functional analysis revealed that upregulated genes in the TEX-C1 subtype were significantly enriched in immune response and signal transduction pathways, and upregulated genes in the TEX-C2 subtype were predominantly associated with cell fate and nervous system development pathways. Notably, patients with activated T-cell activity status in the TEX-C1 subgroup demonstrated a significantly worse prognosis than those with severe T cell exhaustion status in the TEX-C2 subgroup. Finally, we proposed a machine-learning-derived novel gene signature comprising 12 TEX-related genes (12TexSig) to indicate tumour subtyping. In the TCGA cohort, the 12TexSig demonstrated the ability to accurately predict the prognosis of GBM patients, and this prognostic value was further confirmed in two independent external cohorts. Taken together, our results suggest that the TEX-derived subtyping and gene signature has the potential to serve as a clinically helpful biomarker for guiding the management of GBM patients, pending further prospective validation.

FOXO1 promotes the expression of canonical WNT target genes in examined basal-like breast and glioblastoma multiforme cancer cells

Basal-like breast cancer (BBC) and glioblastoma multiforme (GBM) are aggressive cancers associated with poor prognosis. BBC and GBM have stem cell-like gene expression signatures, which are in part driven by forkhead box O (FOXO) transcription factors. To gain further insight into the impact of FOXO1 in BBC, we treated BT549 cells with AS1842856 and performed RNA sequencing. AS1842856 binds to unphosphorylated FOXO1 and inhibits its ability to directly bind to DNA. Gene Set Enrichment Analysis indicated that a set of WNT pathway target genes, including lymphoid enhancer-binding factor 1 (LEF1) and transcription factor 7 (TCF7), were robustly induced after AS1842856 treatment. These same genes were also induced in GBM cell lines U87MG, LN18, LN229, A172, and DBTRG upon AS1842856 treatment. By contrast, follow-up RNA interference (RNAi) targeting of FOXO1 led to reduced LEF1 and TCF7 gene expression in BT549 and U87MG cells. In agreement with RNAi experiments, CRISPR Cas9-mediated FOXO1 disruption reduced the expression of canonical WNT genes LEF1 and TCF7 in U87MG cells. The loss of TCF7 gene expression in FOXO1 disruption mutants was restored by exogenous expression of the DNA-binding-deficient FOXO1-H215R. Therefore, FOXO1 induces TCF7 in a DNA-binding-independent manner, similar to other published FOXO1-activated genes such as TCF4 and hes family bHLH transcription factor 1. Our work demonstrates that FOXO1 promotes canonical WNT gene expression in examined BBC and GBM cells, similar to results found in Drosophila melanogaster, T-cell development, and murine acute myeloid leukemia models.

Exosomal non-coding RNAs in glioma progression: insights into tumor microenvironment dynamics and therapeutic implications

Gliomas are the most common and deadly types of brain tumors, known for their extensive genetic and epigenetic variability, which poses considerable challenges for pharmacological treatment. Glioma heterogeneity is also related to their intricate and dynamic tumor microenvironment (TME), which comprises a diverse array of cell types, including immune cells, vascular cells, glial cells, and neural precursors, collectively influencing tumor behavior and progression. A pivotal aspect of this intercellular communication relies on the exchange of extracellular vesicles (EVs), which contain and transfer complex molecular cargoes typical of their cells of origin, such as proteins, lipids, carbohydrates, metabolites, and non-coding RNAs (ncRNAs), that encompass microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Glioma cells actively release EVs loaded with specific ncRNAs that can target genes and other ncRNAs in recipient cells residing within the TME. Among these recipient cells, prominent players include tumor-associated macrophages and microglia (TAMs), non-neoplastic astrocytes and endothelial cells. The intricate interplay between EVs derived from glioma cells and these recipient cells significantly contributes to the establishment of a tumor-permissive microenvironment, promoting tumor cell proliferation, migration, angiogenesis, and invasion, by targeting various downstream pathways. This review critically examines the current understanding of the intricate interplay between glioma, exosomal ncRNAs, and various components of the glioma TME. By shedding light on the roles of ncRNAs in mediating intercellular communication, this review underscores their significance in orchestrating TME transformation and highlights their potential as novel therapeutic targets for effectively tackling glioma progression.

Amyloids and brain cancer: molecular linkages and crossovers

Amyloids are high-order proteinaceous formations deposited in both intra- and extracellular spaces. These aggregates have tendencies to deregulate cellular physiology in multiple ways; for example, altered metabolism, mitochondrial dysfunctions, immune modulation, etc. When amyloids are formed in brain tissues, the endpoint often is death of neurons. However, interesting but least understood is a close connection of amyloids with another set of conditions in which brain cells proliferate at an extraordinary rate and form tumor inside brain. Glioblastoma is one such condition. Increasing number of evidence indicate a possible link between amyloid formation and depositions in brain tumors. Several proteins associated with cell cycle regulation and apoptotic pathways themselves have shown to possess high tendencies to form amyloids. Tumor suppressor protein p53 is one prominent example that mutate, oligomerize and form amyloids leading to loss- or gain-of-functions and cause increased cell proliferation and malignancies. In this review article, we present available examples, genetic links and common pathways that indicate that possibly the two distantly placed pathways: amyloid formation and developing cancers in the brain have similarities and are mechanistically intertwined together.

Comparative Analysis of the GNAI Family Genes in Glioblastoma through Transcriptomics and Single-Cell Technologies

Glioblastoma multiforme (GBM) is one of the most aggressive cancers with a low overall survival rate. The treatment of GBM is challenging due to the presence of the blood-brain barrier (BBB), which hinders drug delivery. Invasive procedures alone are not effective at completely removing such tumors. Hence, identifying the crucial pathways and biomarkers for the treatment of GBM is of prime importance. We conducted this study to identify the pathways associated with GBM. We used The Cancer Genome Atlas (TCGA) GBM genomic dataset to identify differentially expressed genes (DEGs). We investigated the prognostic values of the guanine nucleotide-binding protein G(i) alpha subunit (GNAI) family of genes in GBM using a Chinese Glioma Genome Atlas (CGGA) dataset. Within this dataset, we observed the association in the tumor microenvironment between the gene expression of GNAI subunit 3 (GNAI3) and a poor prognosis. MetaCore and gene ontology (GO) analyses were conducted to explore the role of GNAI3 in co-expressed genes and associated signaling pathways using a transcript analysis. Notable pathways included "Cytoskeleton remodeling regulation of actin cytoskeleton organization by the kinase effectors of Rho GTPases" and "Immune response B cell antigen receptor (BCR) pathway". A single-cell analysis was used to assess GNAI3 expression in GBM. The results demonstrated that GNAI family genes, specifically GNAI3, were significantly associated with carcinogenesis and malignancy in GBM patients. Our findings suggest that the GNAI3 gene holds potential as a prognostic biomarker for GBM.

Drug resistance in glioblastoma: from chemo- to immunotherapy

As the most common and aggressive type of primary brain tumor in adults, glioblastoma is estimated to end over 10,000 lives each year in the United States alone. Stand treatment for glioblastoma, including surgery followed by radiotherapy and chemotherapy (i.e., Temozolomide), has been largely unchanged since early 2000. Cancer immunotherapy has significantly shifted the paradigm of cancer management in the past decade with various degrees of success in treating many hematopoietic cancers and some solid tumors, such as melanoma and non-small cell lung cancer (NSCLC). However, little progress has been made in the field of neuro-oncology, especially in the application of immunotherapy to glioblastoma treatment. In this review, we attempted to summarize the common drug resistance mechanisms in glioblastoma from Temozolomide to immunotherapy. Our intent is not to repeat the well-known difficulty in the area of neuro-oncology, such as the blood-brain barrier, but to provide some fresh insights into the molecular mechanisms responsible for resistance by summarizing some of the most recent literature. Through this review, we also hope to share some new ideas for improving the immunotherapy outcome of glioblastoma treatment.

Targeting the multidrug and toxin extrusion 1 gene (SLC47A1) sensitizes glioma stem cells to temozolomide

Glioblastoma multiforme (GBM) is the most aggressive type of brain tumor, with an extremely poor prognosis due to resistance to standard-of-care treatments. Strong evidence suggests that the small population of glioma stem cells (GSCs) contributes to the aggressiveness of GBM. One of the mechanisms that promote GSC progression is the dysregulation of membrane transporters, which mediate the influx and efflux of substances to maintain cellular homeostasis. Here, we investigated the role of multidrug and toxin extrusion transporter gene SLC47A1 in GSCs. Results show that SLC47A1 is highly expressed in GSCs compared to non-stem cell glioma cells, and non-tumor cells. Additionally, in-silico analysis of public datasets showed that high SLC47A1 expression is linked to malignancy and a poor prognosis in glioma patients. Further, SLC47A1 expression is correlated with important biological processes and signaling pathways that support tumor growth. Meanwhile, silencing SLC47A1 by short-hairpin RNA (shRNA) influenced cell viability and self-renewal activity in GSCs. Interestingly, SLC47A1 shRNA knockdown or pharmacological inhibition potentiates the effect of temozolomide (TMZ) in GSC cells. The findings suggest that SLC47A1 could serve as a useful therapeutic target for gliomas.

Vascular Immune Evasion of Mesenchymal Glioblastoma Is Mediated by Interaction and Regulation of VE-Cadherin on PD-L1

The mesenchymal subtype of glioblastoma (mGBM), which is characterized by rigorous vasculature, resists anti-tumor immune therapy. Here, we investigated the mechanistic link between tumor vascularization and the evasion of immune surveillance. Clinical datasets with GBM transcripts showed that the expression of the mesenchymal markers YKL-40 (CHI3L1) and Vimentin is correlated with elevated expression of PD-L1 and poor disease survival. Interestingly, the expression of PD-L1 was predominantly found in vascular endothelial cells. Orthotopic transplantation of glioma cells GL261 over-expressing YKL-40 in mice showed increased angiogenesis and decreased CD8+ T cell infiltration, resulting in a reduction in mouse survival. The exposure of recombinant YKL-40 protein induced PD-L1 and VE-cadherin (VE-cad) expression in endothelial cells and drove VE-cad-mediated nuclear translocation of β-catenin/LEF, where LEF upregulated PD-L1 expression. YKL-40 stimulated the dissociation of VE-cad from PD-L1, rendering PD-L1 available to interact with PD-1 from CD8+-positive TALL-104 lymphocytes and inhibit TALL-104 cytotoxicity. YKL-40 promoted TALL-104 cell migration and adhesion to endothelial cells via CCR5-dependent chemotaxis but blocked its anti-vascular immunity. Knockdown of VE-cad or the PD-L1 gene ablated the effects of YKL-40 and reinvigorated TALL-104 cell immunity against vessels. In summary, our study demonstrates a novel vascular immune escape mechanism by which mGBM promotes tumor vascularization and malignant transformation.

Emerging Role of Glioma Stem Cells in Mechanisms of Therapy Resistance

Since their discovery at the beginning of this millennium, glioma stem cells (GSCs) have sparked extensive research and an energetic scientific debate about their contribution to glioblastoma (GBM) initiation, progression, relapse, and resistance. Different molecular subtypes of GBM coexist within the same tumor, and they display differential sensitivity to chemotherapy. GSCs contribute to tumor heterogeneity and recapitulate pathway alterations described for the three GBM subtypes found in patients. GSCs show a high degree of plasticity, allowing for interconversion between different molecular GBM subtypes, with distinct proliferative potential, and different degrees of self-renewal and differentiation. This high degree of plasticity permits adaptation to the environmental changes introduced by chemo- and radiation therapy. Evidence from mouse models indicates that GSCs repopulate brain tumors after therapeutic intervention, and due to GSC plasticity, they reconstitute heterogeneity in recurrent tumors. GSCs are also inherently resilient to standard-of-care therapy, and mechanisms of resistance include enhanced DNA damage repair, MGMT promoter demethylation, autophagy, impaired induction of apoptosis, metabolic adaptation, chemoresistance, and immune evasion. The remarkable oncogenic properties of GSCs have inspired considerable interest in better understanding GSC biology and functions, as they might represent attractive targets to advance the currently limited therapeutic options for GBM patients. This has raised expectations for the development of novel targeted therapeutic approaches, including targeting GSC plasticity, chimeric antigen receptor T (CAR T) cells, and oncolytic viruses. In this review, we focus on the role of GSCs as drivers of GBM and therapy resistance, and we discuss how insights into GSC biology and plasticity might advance GSC-directed curative approaches.