Glioblastoma and Other Primary Brain Malignancies in Adults: A Review

Gastric cancer with brain metastasis: from molecular characteristics and treatment

Gastric cancer is one of the cancers with increasing incidence and ranks fourth globally among the most frequent causes of cancer-related mortality. Early gastric cancer is often asymptomatic or presents with atypical symptoms, and the majority of patients present with advanced disease upon diagnosis. Brain metastases are present in approximately 1% of gastric cancer patients at the time of diagnosis, which significantly contributed to the overall mortality of the disease worldwide. Conventional therapies for patients with brain metastases remain limited and the median overall survival of patients is only 8 months in advanced cases. Recent studies have improved our understanding of the molecular mechanisms underlying gastric cancer brain metastases, and immunotherapy has become an important treatment option in combination with radiotherapy, chemotherapy, targeted therapy and surgery. This review aims to provide insight into the cellular processes involved in gastric cancer brain metastases, discuss diagnostic approaches, evaluate the integration of immune checkpoint inhibitors into treatment and prognosis, and explore the predictive value of biomarkers in immunotherapy.

Revealing the role of SPP1+ macrophages in glioma prognosis and therapeutic targeting by investigating tumor-associated macrophage landscape in grade 2 and 3 gliomas

BACKGROUND

Glioma is a highly heterogeneous brain tumor categorized into World Health Organization (WHO) grades 1-4 based on its malignancy. The suppressive immune microenvironment of glioma contributes significantly to unfavourable patient outcomes. However, the cellular composition and their complex interplays within the glioma environment remain poorly understood, and reliable prognostic markers remain elusive. Therefore, in-depth exploration of the tumor microenvironment (TME) and identification of predictive markers are crucial for improving the clinical management of glioma patients.

RESULTS

Our analysis of single-cell RNA-sequencing data from glioma samples unveiled the immunosuppressive role of tumor-associated macrophages (TAMs), mediated through intricate interactions with tumor cells and lymphocytes. We also discovered the heterogeneity within TAMs, among which a group of suppressive TAMs named TAM-SPP1 demonstrated a significant association with Epidermal Growth Factor Receptor (EGFR) amplification, impaired T cell response and unfavourable patient survival outcomes. Furthermore, by leveraging genomic and transcriptomic data from The Cancer Genome Atlas (TCGA) dataset, two distinct molecular subtypes with a different constitution of TAMs, EGFR status and clinical outcomes were identified. Exploiting the molecular differences between these two subtypes, we developed a four-gene-based prognostic model. This model displayed strong associations with an elevated level of suppressive TAMs and could be used to predict anti-tumor immune response and prognosis in glioma patients.

CONCLUSION

Our findings illuminated the molecular and cellular mechanisms that shape the immunosuppressive microenvironment in gliomas, providing novel insights into potential therapeutic targets. Furthermore, the developed prognostic model holds promise for predicting immunotherapy response and assisting in more precise risk stratification for glioma patients.

High costs, low quality of life, reduced survival, and room for improving treatment: an analysis of burden and unmet needs in glioma

Gliomas are a group of heterogeneous tumors that account for substantial morbidity, mortality, and costs to patients and healthcare systems globally. Survival varies considerably by grade, histology, biomarkers, and genetic alterations such as IDH mutations and MGMT promoter methylation, and treatment, but is poor for some grades and histologies, with many patients with glioblastoma surviving less than a year from diagnosis. The present review provides an introduction to glioma, including its classification, epidemiology, economic and humanistic burden, as well as treatment options. Another focus is on treatment recommendations for IDH-mutant astrocytoma, IDH-mutant oligodendroglioma, and glioblastoma, which were synthesized from recent guidelines. While recommendations are nuanced and reflect the complexity of the disease, maximum safe resection is typically the first step in treatment, followed by radiotherapy and/or chemotherapy using temozolomide or procarbazine, lomustine, and vincristine. Immunotherapies and targeted therapies currently have only a limited role due to disappointing clinical trial results, including in recurrent glioblastoma, for which the nitrosourea lomustine remains the de facto standard of care. The lack of treatment options is compounded by frequently suboptimal clinical practice, in which patients do not receive adequate therapy after resection, including delayed, shortened, or discontinued radiotherapy and chemotherapy courses due to treatment side effects. These unmet needs will require significant efforts to address, including a continued search for novel treatment options, increased awareness of clinical guidelines, improved toxicity management for chemotherapy, and the generation of additional and more robust clinical and health economic evidence.

The potential of DEirlncRNAs: A novel approach to predict glioblastoma prognosis

Background

Despite tremendous evolution in therapies, the prognosis of glioblastoma (GBM) remains grim, which calls for innovative approaches to optimize chemotherapy efficacy and predict risk.

Methods

The transcriptome and clinical data of GBM were acquired from the Cancer Genome Atlas (TCGA), followed by the identification of differentially expressed immune-related long noncoding RNAs (DEirlncRNAs) with Pearson correlation and limma packet analyses. Survival-related DEirlncRNA pairs were screened with univariate Cox proportional hazard regression. Prognostic markers were obtained, and risk scores were calculated with Lasso regression and multivariate Cox risk regression analyses. The association of the prognostic risk model with immune cell infiltration was evaluated by comprehensively analyzing tumor-infiltrating immune cells with TIMER, XCELL, CIBERSORT, QUANTISEQ, and EPIC. Differences in half-maximal inhibitory concentration (IC50) values between the high- and low-risk groups were assessed with the Wilcoxon signed-rank test.

Results

A total of 276 DEirlncRNAs were identified, followed by the visualization of their expression patterns. Two prognosis-related DEirlncRNA pairs were screened, with high accuracy and reliability. The constructed prognostic risk model effectively distinguished between high- and low-risk patients, and significant differences were observed in survival outcomes between the high- and low-risk groups. Furthermore, risk scores were associated with tumor-infiltrating immune cells and DEirlncRNA expression. Additionally, the risk model had a correlation with the effectiveness of commonly used chemotherapeutic agents, providing clues into potential treatment responses.

Conclusions

In our study, a novel signature was constructed with paired DEirlncRNAs (regardless of their expression), which holds significant clinical predictive value and is a potential breakthrough for personalized management of 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.

CDKN2A promoter methylation enhances self-renewal of glioblastoma stem cells and confers resistance to carmustine

BACKGROUND

Glioblastoma, a highly aggressive form of brain cancer, poses significant challenges due to its resistance to therapy and high recurrence rates. This study aimed to investigate the expression and functional implications of CDKN2A, a key tumor suppressor gene, in glioblastoma cells, building upon the existing background of knowledge in this field.

METHOD

Quantitative reverse transcription PCR (qRT-PCR) analysis was performed to evaluate CDKN2A expression in U87 glioblastoma cells compared to normal human astrocytes (NHA). CDKN2A expression levels were manipulated using small interfering RNA (siRNA) and CDKN2A overexpression vector. Cell viability assays and carmustine sensitivity tests were conducted to assess the impact of CDKN2A modulation on glioblastoma cell viability and drug response. Sphere formation assays and western blot analysis were performed to investigate the role of CDKN2A in glioblastoma stem cell (GSC) self-renewal and pluripotency marker expression. Additionally, methylation-specific PCR (MSP) assays and demethylation treatment were employed to elucidate the mechanism of CDKN2A downregulation in U87 cells.

RESULT

CDKN2A expression was significantly reduced in glioblastoma cells compared to NHA. CDKN2A overexpression resulted in decreased cell viability and enhanced sensitivity to carmustine treatment. CDKN2A inhibition promoted self-renewal capacity and increased pluripotency marker expression in U87 cells. CDKN2A upregulation led to elevated protein levels of p16INK4a, p14ARF, P53, and P21, which are involved in cell cycle regulation. CDKN2A downregulation in U87 cells was associated with high promoter methylation, which was reversed by treatment with a demethylating agent.

CONCLUSION

Our findings demonstrate that CDKN2A downregulation in glioblastoma cells is associated with decreased cell viability, enhanced drug resistance, increased self-renewal capacity, and altered expression of pluripotency markers. The observed CDKN2A expression changes are mediated by promoter methylation. These results highlight the potential role of CDKN2A as a therapeutic target and prognostic marker in glioblastoma.

Suppression of ITPKB degradation by Trim25 confers TMZ resistance in glioblastoma through ROS homeostasis

Temozolomide (TMZ) represents a standard-of-care chemotherapeutic agent in glioblastoma (GBM). However, the development of drug resistance constitutes a significant hurdle in the treatment of malignant glioma. Although specific innovative approaches, such as immunotherapy, have shown favorable clinical outcomes, the inherent invasiveness of most gliomas continues to make them challenging to treat. Consequently, there is an urgent need to identify effective therapeutic targets for gliomas to overcome chemoresistance and facilitate drug development. This investigation used mass spectrometry to examine the proteomic profiles of six pairs of GBM patients who underwent standard-of-care treatment and surgery for both primary and recurrent tumors. A total of 648 proteins exhibiting significant differential expression were identified. Gene Set Enrichment Analysis (GSEA) unveiled notable alterations in pathways related to METABOLISM_OF_LIPIDS and BIOLOGICAL_OXIDATIONS between the primary and recurrent groups. Validation through glioma tissue arrays and the Xiangya cohort confirmed substantial upregulation of inositol 1,4,5-triphosphate (IP3) kinase B (ITPKB) in the recurrence group, correlating with poor survival in glioma patients. In TMZ-resistant cells, the depletion of ITPKB led to an increase in reactive oxygen species (ROS) related to NADPH oxidase (NOX) activity and restored cell sensitivity to TMZ. Mechanistically, the decreased phosphorylation of the E3 ligase Trim25 at the S100 position in recurrent GBM samples accounted for the weakened ITPKB ubiquitination. This, in turn, elevated ITPKB stability and impaired ROS production. Furthermore, ITPKB depletion or the ITPKB inhibitor GNF362 effectively overcome TMZ chemoresistance in a glioma xenograft mouse model. These findings reveal a novel mechanism underlying TMZ resistance and propose ITPKB as a promising therapeutic target for TMZ-resistant GBM.

Designing Gold Nanoparticles for Precise Glioma Treatment: Challenges and Alternatives

Glioblastoma multiforme (GBM) is a glioma and the most aggressive type of brain tumor with a dismal average survival time, despite the standard of care. One promising alternative therapy is boron neutron capture therapy (BNCT), which is a noninvasive therapy for treating locally invasive malignant tumors, such as glioma. BNCT involves boron-10 isotope capturing neutrons to form boron-11, which then releases radiation directly into tumor cells with minimal damage to healthy tissues. This therapy lacks clinically approved targeted blood-brain-barrier-permeating delivery vehicles for the central nervous system (CNS) entry of therapeutic boron-10. Gold nanoparticles (GNPs) are selective and effective drug-delivery vehicles because of their desirable properties, facile synthesis, and biocompatibility. This review discusses biomedical/therapeutic applications of GNPs as a drug delivery vehicle, with an emphasis on their potential for carrying therapeutic drugs, imaging agents, and GBM-targeting antibodies/peptides for treating glioma. The constraints of GNP therapeutic efficacy and biosafety are discussed.

Integrated multiomic analysis reveals disulfidptosis subtypes in glioblastoma: implications for immunotherapy, targeted therapy, and chemotherapy

Introduction

Glioblastoma (GBM) presents significant challenges due to its malignancy and limited treatment options. Precision treatment requires subtyping patients based on prognosis. Disulfidptosis, a novel cell death mechanism, is linked to aberrant glucose metabolism and disulfide stress, particularly in tumors expressing high levels of SLC7A11. The exploration of disulfidptosis may provide a new perspective for precise diagnosis and treatment of glioblastoma.

Methods

Transcriptome sequencing was conducted on samples from GBM patients treated at Tiantan Hospital (January 2022 - December 2023). Data from CGGA and TCGA databases were collected. Consensus clustering based on disulfidptosis features categorized GBM patients into two subtypes (DRGclusters). Tumor immune microenvironment, response to immunotherapy, and drug sensitivity were analyzed. An 8-gene disulfidptosis-based subtype predictor was developed using LASSO machine learning algorithm and validated on CGGA dataset.

Results

Patients in DRGcluster A exhibited improved overall survival (OS) compared to DRGcluster B. DRGcluster subtypes showed differences in tumor immune microenvironment and response to immunotherapy. The predictor effectively stratified patients into high and low-risk groups. Significant differences in IC50 values for chemotherapy and targeted therapy were observed between risk groups.

Discussion

Disulfidptosis-based classification offers promise as a prognostic predictor for GBM. It provides insights into tumor immune microenvironment and response to therapy. The predictor aids in patient stratification and personalized treatment selection, potentially improving outcomes for GBM patients.

Targeting SIRT3 sensitizes glioblastoma to ferroptosis by promoting mitophagy and inhibiting SLC7A11

Glioblastoma (GBM) cells require large amounts of iron for tumor growth and progression, which makes these cells vulnerable to destruction via ferroptosis induction. Mitochondria are critical for iron metabolism and ferroptosis. Sirtuin-3 (SIRT3) is a deacetylase found in mitochondria that regulates mitochondrial quality and function. This study aimed to characterize SIRT3 expression and activity in GBM and investigate the potential therapeutic effects of targeting SIRT3 while also inducing ferroptosis in these cells. We first found that SIRT3 expression was higher in GBM tissues than in normal brain tissues and that SIRT3 protein expression was upregulated during RAS-selective lethal 3 (RSL3)-induced GBM cell ferroptosis. We then observed that inhibition of SIRT3 expression and activity in GBM cells sensitized GBM cells to RSL3-induced ferroptosis both in vitro and in vivo. Mechanistically, SIRT3 inhibition led to ferrous iron and ROS accumulation in the mitochondria, which triggered mitophagy. RNA-Sequencing analysis revealed that upon SIRT3 knockdown in GBM cells, the mitophagy pathway was upregulated and SLC7A11, a critical antagonist of ferroptosis via cellular import of cystine for glutathione (GSH) synthesis, was downregulated. Forced expression of SLC7A11 in GBM cells with SIRT3 knockdown restored cellular cystine uptake and consequently the cellular GSH level, thereby partially rescuing cell viability upon RSL3 treatment. Furthermore, in GBM cells, SIRT3 regulated SLC7A11 transcription through ATF4. Overall, our study results elucidated novel mechanisms underlying the ability of SIRT3 to protect GBM from ferroptosis and provided insight into a potential combinatorial approach of targeting SIRT3 and inducing ferroptosis for GBM treatment.

Glioblastoma Therapy: Past, Present and Future

Glioblastoma (GB) stands out as the most prevalent and lethal form of brain cancer. Although great efforts have been made by clinicians and researchers, no significant improvement in survival has been achieved since the Stupp protocol became the standard of care (SOC) in 2005. Despite multimodality treatments, recurrence is almost universal with survival rates under 2 years after diagnosis. Here, we discuss the recent progress in our understanding of GB pathophysiology, in particular, the importance of glioma stem cells (GSCs), the tumor microenvironment conditions, and epigenetic mechanisms involved in GB growth, aggressiveness and recurrence. The discussion on therapeutic strategies first covers the SOC treatment and targeted therapies that have been shown to interfere with different signaling pathways (pRB/CDK4/RB1/P16ink4, TP53/MDM2/P14arf, PI3k/Akt-PTEN, RAS/RAF/MEK, PARP) involved in GB tumorigenesis, pathophysiology, and treatment resistance acquisition. Below, we analyze several immunotherapeutic approaches (i.e., checkpoint inhibitors, vaccines, CAR-modified NK or T cells, oncolytic virotherapy) that have been used in an attempt to enhance the immune response against GB, and thereby avoid recidivism or increase survival of GB patients. Finally, we present treatment attempts made using nanotherapies (nanometric structures having active anti-GB agents such as antibodies, chemotherapeutic/anti-angiogenic drugs or sensitizers, radionuclides, and molecules that target GB cellular receptors or open the blood-brain barrier) and non-ionizing energies (laser interstitial thermal therapy, high/low intensity focused ultrasounds, photodynamic/sonodynamic therapies and electroporation). The aim of this review is to discuss the advances and limitations of the current therapies and to present novel approaches that are under development or following clinical trials.

The anticancer activity of bile acids in drug discovery and development

Bile acids (BAs) constitute essential components of cholesterol metabolites that are synthesized in the liver, stored in the gallbladder, and excreted into the intestine through the biliary system. They play a crucial role in nutrient absorption, lipid and glucose regulation, and the maintenance of metabolic homeostasis. In additional, BAs have demonstrated the ability to attenuate disease progression such as diabetes, metabolic disorders, heart disease, and respiratory ailments. Intriguingly, recent research has offered exciting evidence to unveil their potential antitumor properties against various cancer cell types including tamoxifen-resistant breast cancer, oral squamous cell carcinoma, cholangiocarcinoma, gastric cancer, colon cancer, hepatocellular carcinoma, prostate cancer, gallbladder cancer, neuroblastoma, and others. Up to date, multiple laboratories have synthesized novel BA derivatives to develop potential drug candidates. These derivatives have exhibited the capacity to induce cell death in individual cancer cell types and display promising anti-tumor activities. This review extensively elucidates the anticancer activity of natural BAs and synthetic derivatives in cancer cells, their associated signaling pathways, and therapeutic strategies. Understanding of BAs and their derivatives activities and action mechanisms will evidently assist anticancer drug discovery and devise novel treatment.

Signaling Pathways of AXL Receptor Tyrosine Kinase Contribute to the Pathogenetic Mechanisms of Glioblastoma

Brain tumors are a diverse collection of neoplasms affecting the brain with a high prevalence rate in people of all ages around the globe. In this pathological context, glioblastoma, a form of glioma that belongs to the IV-grade astrocytoma group, is the most common and most aggressive form of the primary brain tumors. Indeed, despite the best treatments available including surgery, radiotherapy or a pharmacological approach with Temozolomide, glioblastoma patients' mortality is still high, within a few months of diagnosis. Therefore, to increase the chances of these patients surviving, it is critical to keep finding novel treatment opportunities. In the past, efforts to treat glioblastoma have mostly concentrated on customized treatment plans that target specific mutations such as epidermal growth factor receptor (EGFR) mutations, Neurotrophic Tyrosine Receptor Kinase (NTRK) fusions, or multiple receptors using multi-kinase inhibitors like Sunitinib and Regorafenib, with varying degrees of success. Here, we focused on the receptor tyrosine kinase AXL that has been identified as a mediator for tumor progression and therapy resistance in various cancer types, including squamous cell tumors, small cell lung cancer, and breast cancer. Activated AXL leads to a significant increase in tumor proliferation, tumor cell migration, and angiogenesis in different in vitro and in vivo models of cancer since this receptor regulates interplay with apoptotic, angiogenic and inflammatory pathways. Based on these premises, in this review we mainly focused on the role of AXL in the course of glioblastoma, considering its primary biological mechanisms and as a possible target for the application of the most recent treatments.

Deep learning aided preoperative diagnosis of primary central nervous system lymphoma

The preoperative distinction between glioblastoma (GBM) and primary central nervous system lymphoma (PCNSL) can be difficult, even for experts, but is highly relevant. We aimed to develop an easy-to-use algorithm, based on a convolutional neural network (CNN) to preoperatively discern PCNSL from GBM and systematically compare its performance to experienced neurosurgeons and radiologists. To this end, a CNN-based on DenseNet169 was trained with the magnetic resonance (MR)-imaging data of 68 PCNSL and 69 GBM patients and its performance compared to six trained experts on an external test set of 10 PCNSL and 10 GBM. Our neural network predicted PCNSL with an accuracy of 80% and a negative predictive value (NPV) of 0.8, exceeding the accuracy achieved by clinicians (73%, NPV 0.77). Combining expert rating with automated diagnosis in those cases where experts dissented yielded an accuracy of 95%. Our approach has the potential to significantly augment the preoperative radiological diagnosis of PCNSL.

m6A mRNA Modifications in Glioblastoma: Emerging Prognostic Biomarkers and Therapeutic Targets

Glioblastoma, the most common and aggressive primary brain tumor, is highly invasive and neurologically destructive. The mean survival for glioblastoma patients is approximately 15 months and there is no effective therapy to significantly increase survival times to date. The development of effective therapy including mechanism-based therapies is urgently needed. At a molecular biology level, N6-methyladenine (m6A) mRNA modification is the most abundant posttranscriptional RNA modification in mammals. Recent studies have shown that m6A mRNA modifications affect cell survival, cell proliferation, invasion, and immune evasion of glioblastoma. In addition, m6A mRNA modifications are critical for glioblastoma stem cells, which could initiate the tumor and lead to therapy resistance. These findings implicate the function of m6A mRNA modification in tumorigenesis and progression, implicating its value in prognosis and therapies of human glioblastoma. This review focuses on the potential clinical significance of m6A mRNA modifications in prognostic and therapeutics of glioblastoma. With the identification of small-molecule compounds that activate or inhibit components of m6A mRNA modifications, a promising novel approach for glioblastoma therapy is emerging.

Combination of Oncolytic Virotherapy with Different Antitumor Approaches against Glioblastoma

Glioblastoma is one of the most malignant and aggressive tumors of the central nervous system. Despite the standard therapy consisting of maximal surgical resection and chemo- and radiotherapy, the median survival of patients with this diagnosis is about 15 months. Oncolytic virus therapy is one of the promising areas for the treatment of malignant neoplasms. In this review, we have focused on emphasizing recent achievements in virotherapy, both as a monotherapy and in combination with other therapeutic schemes to improve survival rate and quality of life among patients with glioblastoma.

Understanding the glioblastoma tumor microenvironment: leveraging the extracellular matrix to increase immunotherapy efficacy

Glioblastoma (GBM) accounts for approximately half of all malignant brain tumors, and it remains lethal with a five-year survival of less than 10%. Despite the immense advancements in the field, it has managed to evade even the most promising therapeutics: immunotherapies. The main reason is the highly spatiotemporally heterogeneous and immunosuppressive GBM tumor microenvironment (TME). Accounting for this complex interplay of TME-driven immunosuppression is key to developing effective therapeutics. This review will explore the immunomodulatory role of the extracellular matrix (ECM) by establishing its contribution to the TME as a key mediator of immune responses in GBM. This relationship will help us elucidate therapeutic targets that can be leveraged to develop and deliver more effective immunotherapies.

Integration of Augmented Reality Into Glioma Resection Surgery: A Case Report

Augmented reality (AR) is an exciting technology that has garnered considerable attention in the field of neurosurgery. Despite this, clinical use of this technology is still in its infancy. An area of great potential for this technology is the ability to display 3D anatomy overlaid with the patient to assist with presurgical and intraoperative decision-making. A 39-year-old woman presented with headaches and was experiencing what was described as a whooshing sound. MRI revealed the presence of a large left frontal mass involving the genu of the corpus callosum, with heterogeneous enhancement and central hemorrhagic necrosis, confirmed to be a glioma. She underwent a craniotomy with intraoperative MRI for resection. An augmented reality system was used to superimpose 3D holographic anatomy onto the patient's head for surgical planning. This report highlights a new AR technology and its immediate application to cranial neurosurgery. It is critical to document new uses of this technology as the field continues to integrate AR as well as other next-generation technologies into practice.

The Prognostic Role of Volumetric MRI Evaluation in the Surgical Treatment of Glioblastoma

Background: Glioblastoma is the most common primary brain neoplasm in adults, with a poor prognosis despite a constant effort to improve patient survival. Some neuroradiological volumetric parameters seem to play a predictive role in overall survival (OS) and progression-free survival (PFS). The aim of this study was to analyze the impact of the volumetric areas of contrast-enhancing tumors and perineoplastic edema on the survival of patients treated for glioblastoma. Methods: A series of 87 patients who underwent surgery was retrospectively analyzed; OS and PFS were considered the end points of the study. For each patient, a multidisciplinary revision was conducted in collaboration with the Neuroradiology and Neuro-Oncology Board. Manual and semiautomatic measurements were adopted to perform the radiological evaluation, and the following quantitative parameters were retrospectively analyzed: contrast enhancement preoperative tumor volume (CE-PTV), contrast enhancement postoperative tumor volume (CE-RTV), edema/infiltration preoperative volume (T2/FLAIR-PV), edema/infiltration postoperative volume (T2/FLAIR-RV), necrosis volume inside the tumor (NV), and total tumor volume including necrosis (TV). Results: The median OS value was 9 months, and the median PFS value was 4 months; the mean values were 12.3 and 6.9 months, respectively. Multivariate analysis showed that the OS-related factors were adjuvant chemoradiotherapy (p < 0.0001), CE-PTV < 15 cm3 (p = 0.03), surgical resection > 95% (p = 0.004), and the presence of a "pseudocapsulated" radiological morphology (p = 0.04). Conclusions: Maximal safe resection is one of the most relevant predictive factors for patient survival. Semiautomatic preoperative MRI evaluation could play a key role in prognostically categorizing these tumors.

Molecular neuropathology: an essential and evolving toolbox for the diagnosis and clinical management of central nervous system tumors

Molecular profiling has transformed the diagnostic workflow of CNS tumors during the last years. The latest WHO classification of CNS tumors (5th edition), published in 2021, pushed forward the integration between histopathological features and molecular hallmarks to achieve reproducible and clinically relevant diagnoses. To address these demands, pathologists have to appropriately deal with multiple molecular assays mainly including DNA methylation profiling and DNA/RNA next generation sequencing. Tumor classification by DNA methylation profiling is now a critical tool for many diagnostic tasks in neuropathology including the assessment of complex cases, to evaluate novel tumor types and to perform tumor subgrouping in hetereogenous entities like medulloblastoma or ependymoma. DNA/RNA NGS allow the detection of multiple molecular alterations including single nucleotide variations, small insertions/deletions (InDel), and gene fusions. These molecular markers can provide key insights for diagnosis, for example, if a tumor-specific mutation is detected, but also for treatment since targeted therapies are progressively entering the clinical practice. In the present review, a brief, but comprehensive overview of these tools will be provided, discussing their technical specifications, diagnostic value, and potential limitations. Moreover, the importance of molecular profiling will be shown in a representative series of CNS neoplasms including both the most frequent tumor types and other selected entities for which molecular characterization plays a critical role.

Changes in the Epidemiologic Pattern of Primary CNS Tumors in Response to the Aging Population: An Updated Nationwide Cancer Registry Data in the Republic of Korea

PURPOSE

Primary CNS tumors (PCNSTs) are tumors originating from the brain and surrounding tissues. These tumors account for a significant proportion of cancer deaths and morbidity globally. Accurate epidemiologic data are essential for shaping clinical practices, research priorities, and health care policies. This study presents the latest 2020 national data on PCNSTs from the Republic of Korea (ROK) and explores the trends in incidence and their societal implications in the context of an aging population.

METHODS

This is a cross-sectional, observational study conducted using data sourced from the Korea National Cancer Incidence Database by the Korea Central Cancer Registry. The study analyzed national data on PCNSTs in the ROK for the years 2010, 2013, 2016, and 2020.

RESULTS

In 2020, 15,568 new PCNST cases were diagnosed in the ROK. The overall crude rate was 30.32, and the age-standardized rate was 19.37 per 100,000 persons. A decade-long trend analysis revealed an increasing trend in newly diagnosed glioblastoma and lymphoma, and a decreasing trend in embryonal tumors, in relation to the aging population of the ROK.

CONCLUSION

This study shows the significant impact of demographic shifts on the epidemiologic patterns of PCNSTs in the ROK. Our findings emphasize the need for collaborative efforts to address the rising challenges posed by the changing incidence of PCNSTs related to an aging population.

Regulation of cancer stem cells and immunotherapy of glioblastoma (Review)

Glioblastoma (GB) is one of the most adverse diagnoses in oncology. Complex current treatment results in a median survival of 15 months. Resistance to treatment is associated with the presence of cancer stem cells (CSCs). The present review aimed to analyze the mechanisms of CSC plasticity, showing the particular role of β-catenin in regulating vital functions of CSCs, and to describe the molecular mechanisms of Wnt-independent increase of β-catenin levels, which is influenced by the local microenvironment of CSCs. The present review also analyzed the reasons for the low effectiveness of using medication in the regulation of CSCs, and proposed the development of immunotherapy scenarios with tumor cell vaccines, containing heterogenous cancer cells able of producing a multidirectional antineoplastic immune response. Additionally, the possibility of managing lymphopenia by transplanting hematopoietic stem cells from a healthy sibling and using clofazimine or other repurposed drugs that reduce β-catenin concentration in CSCs was discussed in the present study.

MiR-4524b-5p-targeting ALDH1A3 attenuates the proliferation and radioresistance of glioblastoma via PI3K/AKT/mTOR signaling

Increasing evidence has revealed a strong connection between the aldehyde dehydrogenase family member ALDH1A3 and tumorigenesis, therapy resistance, and prognosis in diverse types of cancer. However, the specific miRNA involved in the pathways that regulate ALDH1A3-mediated glioblastoma (GBM) radioresistance remains to be elucidated. In this study, we demonstrated a high expression of ALDH1A3 in GBM cells, which plays a critical role in their proliferation and radioresistance. We also identified miR-4524b-5p, which is downregulated in GBM, as the ALDH1A3 upstream regulator. Overexpression of miR-4524b-5p reduced proliferation and radioresistance in GBM cells. Moreover, silencing ALDH1A3 reduced PI3K/AKT/mTOR signaling and glycolytic activity in GBM cells, whereas inhibiting mTOR reversed the radioresistance effects of ALDH1A3 on these cells. In vivo experiments have evidenced that ALDH1A3 silencing and miR-4524b-5p overexpression significantly reduced tumor growth and GBM cells radioresistance. In summary, targeting the miR-4524b-5p and ALDH1A3 axis is a promising therapeutic strategy for treating GBM.

Roles, underlying mechanisms and clinical significances of LINC01503 in human cancers

Long intergenic non-coding RNA 01503 (LINC01503) is a long non-coding RNA (lncRNA) located on human chromosome 9q34.11. There is compelling evidence indicating that LINC01503 is upregulated in multiple types of tumors and functions as a tumor stimulator. The upregulation of LINC01503 was significantly associated with the risk of 12 tumors and showed a strong correlation with clinicopathological characteristics and poor prognosis in 9 tumors. The expression of LINC01503 is regulated by transcription factors such as TP63, EGR1, c-MYC, GATA1 and AR. The downstream regulatory mechanisms of LINC01503 are complex and multifaceted. LINC01503, as a competing endogenous RNA (ceRNA), regulates gene expression by competitively inhibiting miRNA. LINC01503 may also regulate gene expression via interacting with biomolecules or recruiting chromatin-modifying complexes. In addition, LINC01503 can abnormally activate the ERK/MAPK, PI3K/AKT and Wnt/β-catenin signaling pathways to enhance tumor progression. Here, this review presents an overview of the latest research progress of LINC01503 in the field of oncology, summarizes its comprehensive network involved in multiple cancer molecular mechanisms, and explores its potential applications in cancer diagnosis, prognosis, and treatment.

Biological, diagnostic and therapeutic implications of exosomes in glioma

Despite therapeutic advances, overall survival in glioblastoma is dismal. To optimize progress, a more detailed understanding of glioma's molecular, cellular, and intercellular pathophysiology is needed. Recent investigation has revealed a vital role for exosomes in inter-cellular signaling, tumor cell support, and regulation of the tumor microenvironment. Exosomes carry miRNAs, lncRNAs, mRNAs, proteins, immune regulatory molecules, nucleic acids, and lipids; however, the composition of exosome cargo is variable depending on the cell of origin. Specific exosomal miRNA contents such as miR-21, miR-301a, miR-151a, miR-148a, and miR-5096 are altered in high-grade glioma. Unique proteomic, genomic, and miRNA signatures of tumor exosomes have been associated with disease pathobiology, temozolomide resistance, immunosuppression, and tumor proliferation. Exosomes hold promise for tissue diagnostic glioma diagnosis and monitoring response to therapy. This review summarizes the current understanding of exosomes, their crucial role in glioma pathology, and future directions for their use in diagnosis and treatment. METHODS: The MEDLINE/PubMed database was reviewed for papers written in English and publication dates of 1981-2023, using the search string "Exosome", "Extracellular vesicles", "Glioma", "Exosomes in glioma".

Identification of SRSF10 as a promising prognostic biomarker with functional significance among SRSFs for glioma

AIMS

The serine/arginine-rich splicing factor (SRSF) protein family members are essential mediators of the alternative splicing (AS) regulatory network, which is tightly implicated in cancer progression. However, the expression, clinical correlation, immune infiltration, and prognostic value of SRSFs in gliomas remain unclear.

MATERIALS AND METHODS

Glioma samples were extracted from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) datasets. Several databases, such as HPA, DAVID, UALCAN were used to comprehensively explore the roles of SRSFs. In addition, experimental validation of SRSF10 was also conducted.

KEY FINDINGS

Here, we found the expression alterations of the SRSF family in glioma samples using data from the TCGA and CGGA_325 datasets. Among the 12 genes, most were found to be closely associated with glioma clinical features, which linked to poor prognosis in glioma patients. Interestingly, survival analysis identified only SRSF10 as a potential independent risk prognostic biomarker for glioma patients. Immune analysis indicated that glioma patients with high SRSF10 expression may respond well to immunotherapies targeting immune checkpoint (ICP) genes. Finally, knocking down SRSF10 reduced glioma cell viability, induced G1 cell cycle arrest, and induced the exclusion of bcl-2-associated transcription factor 1 (BCLAF1) exon 5a.

SIGNIFICANCE

Overall, this study uncovers the oncogenic roles of most SRSF family members in glioma, with the exception of SRSF5, while highlighting SRSF10 as a potential novel independent prognostic biomarker for glioma.

Increased interaction between connexin43 and microtubules is critical for glioblastoma stem-like cell maintenance and tumorigenicity

Glioblastoma (GBM) is the most common primary tumor of the central nervous system. One major challenge in GBM treatment is the resistance to chemotherapy and radiotherapy observed in subpopulations of cancer cells, including GBM stem-like cells (GSCs). These cells hold the ability to self-renew or differentiate following treatment, participating in tumor recurrence. The gap junction protein connexin43 (Cx43) has complex roles in oncogenesis and we have previously demonstrated an association between Cx43 and GBM chemotherapy resistance. Here, we report, for the first time, increased direct interaction between non-junctional Cx43 with microtubules in the cytoplasm of GSCs. We hypothesize that non-junctional Cx43/microtubule complexing is critical for GSC maintenance and survival and sought to specifically disrupt this interaction while maintaining other Cx43 functions, such as gap junction formation. Using a Cx43 mimetic peptide of the carboxyl terminal tubulin-binding domain of Cx43 (JM2), we successfully ablated Cx43 interaction with microtubules in GSCs. Importantly, administration of JM2 significantly decreased GSC survival in vitro , and limited GSC-derived tumor growth in vivo . Together, these results identify JM2 as a novel peptide drug to ablate GSCs in GBM treatment.

Surgical site infections after glioblastoma surgery: boon or bane?

BACKGROUND

Surgical site infections (SSIs) are among the most common postoperative complications. Glioblastoma multiforme is the most frequent malignant brain tumor with a dismal prognosis despite combined treatment. The effect of SSIs on the course of glioblastoma patients has not been fully clarified since available data are limited and partially contradictory. The aim of this study is to investigate the impact of SSIs on the course of patients with glioblastoma.

METHODS

The medical records of all patients undergoing surgery for glioblastoma between 2010 and 2020 in our institution were scanned and those with surgical site infections after glioblastoma resection were identified and compared to an age-matched control group. Overall survival and progression-free survival were the primary endpoints followed by the number of hospitalizations and the length of stay in hospital.

RESULTS

Out of 305 patients undergoing surgery for glioblastoma, 38 patients with postoperative surgical site infection after resection were identified and 15 (5 men and 10 women aged between 9 and 72) were included in this study. 23 patients were excluded. The control group consisted of 30 age-matched patients without SSI (18 men and 12 women). There were no significant differences in median overall survival. Progression-free survival was higher in the SSI group. The number of hospitalizations and the length of stay were significantly higher in the SSI group.

CONCLUSION

Our data suggest that SSIs might reduce early recurrences without affecting overall survival. Furthermore, they might decrease health-related quality of life by doubling the total length of hospital stay.

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.

Targeting Innate Immunity in Glioma Therapy

Currently, there is a lack of effective therapies for the majority of glioblastomas (GBMs), the most common and malignant primary brain tumor. While immunotherapies have shown promise in treating various types of cancers, they have had limited success in improving the overall survival of GBM patients. Therefore, advancing GBM treatment requires a deeper understanding of the molecular and cellular mechanisms that cause resistance to immunotherapy. Further insights into the innate immune response are crucial for developing more potent treatments for brain tumors. Our review provides a brief overview of innate immunity. In addition, we provide a discussion of current therapies aimed at boosting the innate immunity in gliomas. These approaches encompass strategies to activate Toll-like receptors, induce stress responses, enhance the innate immune response, leverage interferon type-I therapy, therapeutic antibodies, immune checkpoint antibodies, natural killer (NK) cells, and oncolytic virotherapy, and manipulate the microbiome. Both preclinical and clinical studies indicate that a better understanding of the mechanisms governing the innate immune response in GBM could enhance immunotherapy and reinforce the effects of chemotherapy and radiotherapy. Consequently, a more comprehensive understanding of the innate immune response against cancer should lead to better prognoses and increased overall survival for GBM patients.

KCNA1 promotes the growth and invasion of glioblastoma cells through ferroptosis inhibition via upregulating SLC7A11

BACKGROUND

The high invasiveness and infiltrative nature of Glioblastoma (GBM) pose significant challenges for surgical removal. This study aimed to investigate the role of KCNA1 in GBM progression.

METHODS

CCK8, colony formation assay, scratch assay, transwell assay, and 3D tumor spheroid invasion assays were to determine how KCNA1 affects the growth and invasion of GBM cells. Subsequently, to confirm the impact of KCNA1 in ferroptosis, western blot, transmission electron microscopy and flow cytometry were conducted. To ascertain the impact of KCNA1 in vivo, patient-derived orthotopic xenograft models were established.

RESULTS

In functional assays, KCNA1 promotes the growth and invasion of GBM cells. Besides, KCNA1 can increase the expression of SLC7A11 and protect cells from ferroptosis. The vivo experiments demonstrated that knocking down KCNA1 inhibited the growth and infiltration of primary tumors in mice and extended survival time.

CONCLUSION

Therefore, our research suggests that KCNA1 may promote tumor growth and invasion by upregulating the expression of SLC7A11 and inhibiting ferroptosis, making it a promising therapeutic target for GBM.

Exploring the prognostic potential of m6A methylation regulators in low-grade glioma: implications for tumor microenvironment modulation

BACKGROUND

The biological behavior of low-grade glioma (LGG) is significantly affected by N6-methyladenosine (m6A) methylation, an essential epigenetic alteration. Therefore, it is crucial to create a prognostic model for LGG by utilizing genes that regulate m6A methylation.

METHODS

Using TCGA and GTEx databases. We examined m6A modulator levels in LGG and normal tissues, and investigated PD-L1 and PD-1 expression, immune scores, immune cell infiltration, tumor immune microenvironment (TIME) and potential underlying mechanisms in different LGG clusters. We also performed immunohistochemistry and RT-qPCR to identify essential m6A adjustment factor.

RESULTS

The results showed that m6A regulatory element expression was significantly increased in LGG tissues and was significantly associated with TMIE. A substantial increase in PD-L1 and PD-1 levels in LGG tissues and high-risk cohorts was observed. PD-L1 expression was positively correlated with FTO, ZCCHC4, and HNRNPD, whereas PD-1 expression was negatively correlated with FTO, ZC3H7B, and HNRNPD. The prognostic signature created using regulators of m6A RNA methylation was shown to be strongly associated with the overall survival of LGG patients, and FTO and ZCCHC4 were confirmed as independent prognostic markers by clinical samples. Furthermore, the results revealed different TIME characteristics between the two groups of patients, indicating disrupted signaling pathways associated with LGG.

CONCLUSION

Our results present that the m6A regulators play vital role in regulating PD-L1/PD-1 expression and the infiltration of immune cells, thereby exerting a sizable impact on the TIME of LGG. Therefore, m6A regulators have precise predictive value in the prognosis of LGG.

Immunoediting Dynamics in Glioblastoma: Implications for Immunotherapy Approaches

Glioblastoma is an aggressive primary brain tumor that poses many therapeutic difficulties because of the high rate of proliferation, genetic variability, and its immunosuppressive microenvironment. The theory of cancer immunoediting, which includes the phases of elimination, equilibrium, and escape, offers a paradigm for comprehending interactions between the immune system and glioblastoma. Immunoediting indicates the process by which immune cells initially suppress tumor development, but thereafter select for immune-resistant versions leading to tumor escape and progression. The tumor microenvironment (TME) in glioblastoma is particularly immunosuppressive, with regulatory T cells and myeloid-derived suppressor cells being involved in immune escape. To achieve an efficient immunotherapy for glioblastoma, it is crucial to understand these mechanisms within the TME. Existing immunotherapeutic modalities such as chimeric antigen receptor T cells and immune checkpoint inhibitors have been met with some level of resistance because of the heterogeneous nature of the immune response to glioblastoma. Solving these issues is critical to develop novel strategies capable of modulating the TME and re-establishing normal immune monitoring. Further studies should be conducted to identify the molecular and cellular events that underlie the immunosuppressive tumor microenvironment in glioblastoma. Comprehending and modifying the stages of immunoediting in glioblastoma could facilitate the development of more potent and long-lasting therapies.

Characterization of Prognostic Apoptosis-Related Gene Signature to Evaluate Glioma Immune Microenvironment and Experimental Verification

Purpose: Recently, apoptosis-related genes were shown to modulate cancer immunity. However, the role of apoptosis-related genes in the glioma immune microenvironment (GIME) remains unknown. This study aimed to explore the prognostic value of apoptosis-related genes in glioma. Methods: Doxorubicin was used to induce glioma cell apoptosis, and four differentially expressed apoptosis-related genes were identified: CREM, TNFSF12, PEA15, and PRKCD. Kaplan-Meier analyses, receiver operating characteristic curve analyses, and nomograms were established to determine the relationship between risk markers and the prognosis of patients with glioma. Results: Risk biomarkers were significantly associated with overall survival, immune cell infiltration, and immune checkpoints in patients with glioma. Somatic mutations and anti-PD-1/L1 immunotherapy were associated with worse prognosis in the high-risk group receiving anti-PD-1/L1 therapy. The expression of these four apoptosis-related genes was verified using quantitative polymerase chain reaction and immunohistochemistry, and the relationship between these four genes and apoptosis was examined using flow cytometry. Conclusions: This study suggests that apoptosis-related genes play a critical role in shaping the GIME. Assessing the apoptotic patterns of individual tumors will enhance our understanding of GIME infiltration features and lead to improved strategies for immunotherapy.

Predicting prognosis outcomes of primary central nervous system lymphoma with high-dose methotrexate-based chemotherapeutic treatment using lipidomics

Background

Primary central nervous system lymphoma (PCNSL) is a rare extranodal lymphomatous malignancy which is commonly treated with high-dose methotrexate (HD-MTX)-based chemotherapy. However, the prognosis outcome of HD-MTX-based treatment cannot be accurately predicted using the current prognostic scoring systems, such as the Memorial Sloan-Kettering Cancer Center (MSKCC) score.

Methods

We studied 2 cohorts of patients with PCNSL and applied lipidomic analysis to their cerebrospinal fluid (CSF) samples. After removing the batch effects and features engineering, we applied and compared several classic machine-learning models based on lipidomic data of CSF to predict the relapse of PCNSL in patients who were treated with HD-MTX-based chemotherapy.

Results

We managed to remove the batch effects and get the optimum features of each model. Finally, we found that Cox regression had the best prediction performance (AUC = 0.711) on prognosis outcomes.

Conclusions

We developed a Cox regression model based on lipidomic data, which could effectively predict PCNSL patient prognosis before the HD-MTX-based chemotherapy treatments.

Identification of telomere-associated gene signatures to predict prognosis and drug sensitivity in glioma

OBJECTIVE

Gliomas are a heterogeneous group of brain tumors with distinct biological and clinical properties, leading to significant mortality and morbidity. Emerging evidence shows telomere maintenance has implicated in glioma susceptibility and prognosis. In this study, we comprehensively analyzed gene signatures related to telomere maintenance in glioma and their predictive values for predicting the prognosis and drug sensitivity in glioma.

METHODS

We initially identified telomere-related genes differentially expressed between low-grade glioma (LGG) and glioblastoma (GBM) and accordingly developed a risk model by univariate and multivariate Cox analysis to assess the expressions of telomere-related genes across the risk groups. Finally, to assess these genes in immune function the anti-tumor medications often used in the clinical treatment of glioma, we computed immune cell infiltration analysis and drug sensitivity analysis.

RESULTS

The consensus clustering analysis identified 20 telomere-related genes which split LGG patients into two distinct subtypes. The patient survival, the expressions of key telomere-related DEGs, and immune cell infiltration significantly differed between Cluster 1 and Cluster 2. The LASSO risk model [riskScore=(0.086)*HOXA7+(0.242)*WEE1+(0.247)*IGF2BP3+(0.052)*DUSP10] showed significant differences regarding the 1-, 3-, 5-year overall survival, immune cell infiltration, and drug sensitivity between high- and low-risk groups. The predictive nomogram constructed to quantify the survival probability of each sample at 1, 3, and 5 years was consistent with the actual patient survival.

CONCLUSION

Our comprehensive characterization of telomere-associated gene signatures in glioma reveals their possible roles in the development, tumor microenvironment, and prognosis. The study provides some suggestive relationships between four telomere-related genes (HOXA7, WEE1, IGF2BP3, and DUSP10) and glioma prognosis.

Towards multi-target glioblastoma therapy: Structural, distribution, and functional insights into protein target candidates

Glioblastoma is the most commonly occurring and most lethal primary brain tumor. Treatment options are limited in number and therapeutic development remains a major challenge. However, substantial progress has been made in better understanding the underlying biology of the disease. A recent proteomic meta-analysis revealed that 270 proteins were commonly dysregulated in glioblastoma, highlighting the complexity of the disease. This motivated us to explore potential protein targets which may be collectively inhibited, based on common upregulation, as part of a multi-target therapeutic strategy. Herein, we identify and characterize structural attributes relevant to the druggability of six protein target candidates. Computational analysis of crystal structures revealed druggable cavities in each of these proteins, and various parameters of these cavities were determined. For proteins with inhibitor-bound structures available, inhibitor compounds were found to overlap with the computationally determined cavities upon structural alignment. We also performed bioinformatic analysis for normal transcriptional expression distribution of these proteins across various brain regions and various tissues, as well as gene ontology curation to gain functional insights, as this information is useful for understanding the potential for off-target adverse effects. Our findings represent initial steps towards the development of multi-target glioblastoma therapy and may aid future work exploring similar therapeutic strategies.

Research progress on ferroptosis in gliomas (Review)

Glioma is the most prevalent type of brain tumor characterized by a poor 5-year survival rate and a high mortality rate. Malignant gliomas are commonly treated by surgery, chemotherapy and radiotherapy. However, due to toxicity and resistance to chemoradiotherapy, these treatments can be ineffective. Anxiety and depression are highly prevalent in patients with glioma, adversely affecting disease prognosis and posing societal concerns. Ferroptosis is a type of non-apoptotic, iron-dependent cell death characterized by the accumulation of lethal reactive oxygen species produced by iron metabolism, and it serves a key role in numerous diseases. Regulation of iron phagocytosis may serve as a therapeutic strategy for the development of novel glioma treatments. The present review discusses the mechanisms underlying the occurrence and regulation of ferroptosis, its role in the genesis and evolution of gliomas, and its association with glioma-related anxiety and depression. By exploring potential targets for glioma treatment, the present review provides a theoretical basis for the development of novel therapeutic strategies against glioma.

Directionally non-rotating electric field therapy delivered through implanted electrodes as a glioblastoma treatment platform: A proof-of-principle study

Background

While directionally rotating tumor-treating fields (TTF) therapy has garnered considerable clinical interest in recent years, there has been comparatively less focus on directionally non-rotating electric field therapy (dnEFT).

Methods

We explored dnEFT generated through customized electrodes as a glioblastoma therapy in in vitro and in vivo preclinical models. The effects of dnEFT on tumor apoptosis and microglia/macrophages in the tumor microenvironment were tested using flow-cytometric and qPCR assays.

Results

In vitro, dnEFT generated using a clinical-grade spinal cord stimulator showed antineoplastic activity against independent glioblastoma cell lines. In support of the results obtained using the clinical-grade electrode, dnEFT delivered through a customized, 2-electrode array induced glioblastoma apoptosis. To characterize this effect in vivo, a custom-designed 4-electrode array was fabricated such that tumor cells can be implanted into murine cerebrum through a center channel equidistant from the electrodes. After implantation with this array and luciferase-expressing murine GL261 glioblastoma cells, mice were randomized to dnEFT or placebo. Relative to placebo-treated mice, dnEFT reduced tumor growth (measured by bioluminescence) and prolonged survival (median survival gain of 6.5 days). Analysis of brain sections following dnEFT showed a notable increase in the accumulation of peritumoral macrophage/microglia with increased expression of M1 genes (IFNγ, TNFα, and IL-6) and decreased expression of M2 genes (CD206, Arg, and IL-10) relative to placebo-treated tumors.

Conclusions

Our results suggest therapeutic potential in glioblastoma for dnEFT delivered through implanted electrodes, supporting the development of a proof-of-principle clinical trial using commercially available deep brain stimulator electrodes.

Sensitizing chemotherapy for glioma with fisetin mediated by a microenvironment-responsive nano-drug delivery system

Drug resistance has become an obstacle to successful cancer chemotherapies, with therapeutic agents effectively traversing the blood-brain barrier (BBB) remaining a great challenge. A microenvironment responsive and active targeting nanoparticle was constructed to enhance the penetration of drugs, leading to improved therapeutic effects. Dynamic light scattering demonstrated that the prepared nanoparticle had a uniform size. The cRGD modification renders the nanoparticle with active targeting capabilities to traverse the BBB for chemotherapy. The disulfide-bond-containing nanoparticle can be disintegrated in response to a high concentration of endogenous glutathione (GSH) within the tumor microenvironment (TME) for tumor-specific drug release, resulting in more effective accumulation. Notably, the released fisetin further increased the uptake of doxorubicin by glioma cells and exerted synergistic effects to promote apoptosis, induce cellular G2/M cycle arrest, and inhibit cell proliferation and migration in vitro. Moreover, the nanoparticle showed favorable anti-glioma effects in vivo. Our study provides a new strategy to overcome drug resistance by utilizing a natural product to sensitize conventional chemotherapeutics with well-designed targeted nanodelivery systems for cancer treatment.

Immune Escape in Glioblastoma: Mechanisms of Action and Implications for Immune Checkpoint Inhibitors and CAR T-Cell Therapy

Glioblastoma, the most common primary brain cancer in adults, is characterized by a poor prognosis and resistance to standard treatments. The advent of immunotherapy has revolutionized the treatment of several cancers in recent years but has failed to demonstrate benefit in patients with glioblastoma. Understanding the mechanisms by which glioblastoma exerts tumor-mediated immune suppression in both the tumor microenvironment and the systemic immune landscape is a critical step towards developing effective immunotherapeutic strategies. In this review, we discuss the current understanding of immune escape mechanisms in glioblastoma that compromise the efficacy of immunotherapies, with an emphasis on immune checkpoint inhibitors and chimeric antigen receptor T-cell therapy. In parallel, we review data from preclinical studies that have identified additional therapeutic targets that may enhance overall treatment efficacy in glioblastoma when administered alongside existing immunotherapies.

Unlocking Glioblastoma Secrets: Natural Killer Cell Therapy against Cancer Stem Cells

Glioblastoma (GBM) represents a paramount challenge as the most formidable primary brain tumor characterized by its rapid growth, aggressive invasiveness, and remarkable heterogeneity, collectively impeding effective therapeutic interventions. The cancer stem cells within GBM, GBM stem cells (GSCs), hold pivotal significance in fueling tumor advancement, therapeutic refractoriness, and relapse. Given their unique attributes encompassing self-renewal, multipotent differentiation potential, and intricate interplay with the tumor microenvironment, targeting GSCs emerges as a critical strategy for innovative GBM treatments. Natural killer (NK) cells, innate immune effectors recognized for their capacity to selectively detect and eliminate malignancies without the need for prior sensitization, offer substantial therapeutic potential. Harnessing the inherent capabilities of NK cells can not only directly engage tumor cells but also augment broader immune responses. Encouraging outcomes from clinical investigations underscore NK cells as a potentially effective modality for cancer therapy. Consequently, NK cell-based approaches hold promise for effectively targeting GSCs, thereby presenting an avenue to enhance treatment outcomes for GBM patients. This review outlines GBM's intricate landscape, therapeutic challenges, GSC-related dynamics, and elucidates the potential of NK cell as an immunotherapeutic strategy directed towards GSCs.

Deeper insight into ferroptosis: association with Alzheimer's, Parkinson's disease, and brain tumors and their possible treatment by nanomaterials induced ferroptosis

Ferroptosis is an emerging and novel type of iron-dependent programmed cell death which is mainly caused by the excessive deposition of free intracellular iron in the brain cells. This deposited free iron exerts a ferroptosis pathway, resulting in lipid peroxidation (LiPr). There are mainly three ferroptosis pathways viz. iron metabolism-mediated cysteine/glutamate, and LiPr-mediated. Iron is required by the brain as a redox metal for several physiological activities. Due to the iron homeostasis balance disruption, the brain gets adversely affected which further causes neurodegenerative diseases (NDDs) like Parkinson's and Alzheimer's disease, strokes, and brain tumors like glioblastoma (GBS), and glioma. Nanotechnology has played an important role in the prevention and treatment of these NDDs. A synergistic effect of nanomaterials and ferroptosis could prove to be an effective and efficient approach in the field of nanomedicine. In the current review, the authors have highlighted all the latest research in the field of ferroptosis, specifically emphasizing on the role of major molecular key players and various mechanisms involved in the ferroptosis pathway. Moreover, here the authors have also addressed the correlation of ferroptosis with the pathophysiology of NDDs and theragnostic effect of ferroptosis and nanomaterials for the prevention and treatment of NDDs.

Efficacy of a novel glioma therapy based on ferroptosis induced by layered double hydroxide loaded with simvastatin

Glioma is the most common primary malignant tumor of the nervous system that starts in the glial cells. Its high invasiveness and recurrence pose major challenges to its effective treatment. Ferroptosis is a new type of programmed cell death characterized by intracellular iron overload and accumulation of lipid peroxides. Existing studies have demonstrated the efficacy of targeted ferroptosis therapy in the treatment of glioma. In this study, folic acid (FA)-modified layered double hydroxide loaded with simvastatin (SIM), a ferroptosis drug, was used to prepare a novel ferroptosis nanodrug (FA-LDH@SIM). The prepared nanodrug improved the therapeutic effect of SIM on glioma. Compared with free SIM, FA-LDH@SIM showed greater cytotoxicity, significantly inhibited glioma cell proliferation, and significantly inhibited glioma invasion and migration ability. Furthermore, SIM could induce changes in certain ferroptosis indicators, including increased intracellular LPO, ROS and MDA level, decreased GSH production, increased divalent iron level, and changes in mitochondrial morphology. Further experiments revealed that SIM induced ferroptosis in tumor cells by down-regulating HMGCR expression and inhibiting the mevalonate pathway to down-regulate GPX4 expression. In addition, the FA-LDH@SIM group significantly inhibited tumor growth after treatment in the animal glioma model. These results indicate that the FA-LDH@SIM nanodrug delivery system exhibits excellent anti-tumor effects both in vitro and in vivo, and is an effective method for the treatment of glioma.

Ribosomal S6 protein kinase 4 promotes resistance to EZH2 inhibitors in glioblastoma

Glioblastoma (GBM) is a highly malignant type of brain tumor with limited treatment options. Recent research has focused on epigenetic regulatory factors, such as Enhancer of Zeste Homolog 2 (EZH2), which plays a role in gene expression through epigenetic modifications. EZH2 inhibitors have been developed as potential therapeutic agents for GBM, but resistance to these inhibitors remains a considerable challenge. This study aimed to investigate the role of ribosomal S6 protein kinase 4 (RSK4) in GBM and its association with resistance to EZH2 inhibitors. We first induced drug resistance in primary GBM cell lines by treatment with an EZH2 inhibitor and observed increases in the expression of stemness markers associated with glioblastoma stem cells (GSCs) in the drug-resistant cells. We also found high expression of RSK4 in GBM patient samples and identified the correlation of high RSK4 expression with poor prognosis and GSC marker expression. Further experiments showed that knocking down RSK4 in drug-resistant GBM cells restored their sensitivity to EZH2 inhibitors and decreased the expression of GSC markers, thus reducing their self-renewal capacity. From a mechanistic perspective, we discovered that RSK4 directly phosphorylates EZH2, activating the EZH2/STAT3 pathway and promoting resistance to EZH2 inhibitors in GBM. We also found that combining EZH2 inhibitors with an RSK4 inhibitor called BI-D1870 had better inhibitory effects on GBM occurrence and progression in both in vitro and in vivo experiments. In conclusion, this study demonstrates that RSK4 enhances cancer stemness and mediates resistance to EZH2 inhibitors in GBM. Combination treatment with EZH2 inhibitors and RSK4 inhibitors is a promising potential therapeutic strategy for GBM. Collectively, our results strongly demonstrate that RSK4 regulates the EZH2/STAT3 pathway to promote GSC maintenance and EZH2i resistance in a PRC2-independent manner, indicating that RSK4 is a promising therapeutic target for GBM.

Ganciclovir as a potential treatment for glioma: a systematic review and meta-analysis

BACKGROUND

Glioma is a challenging malignant tumor with a low survival rate and no effective treatment. Recently, ganciclovir, an antiviral drug, combined with gene therapy and its own antiviral ability, has been proposed as a potential treatment for glioma. However, there are differences in the results of various clinical trials. In this study, we conducted a systematic review and meta-analysis to evaluate the efficacy of ganciclovir in treating glioma.

METHODS

We searched databases such as PubMed, EMBASE, and Cochrane Library before March 30, 2023. The search terms included glioma, ganciclovir, valganciclovir and treatment. Calculated 1, 2 and 4-year survival rate by risk difference (RD), and overall survival (OS) by odds ratio (OR).

RESULTS

Five randomized controlled trials (RCTs) with a total of 606 high-grade glioma patients were included. The results showed that ganciclovir can improve 2-yeaer (RD = 0.179, 95% CI 0.012-0.346, P = 0.036) and 4-year survival rate (RD = 0.185, 95% CI 0.069-0.3, P = 0.002) and OS (OR 2.393, 95% CI 1.212-4.728, P = 0.012) compared with the control group.

CONCLUSIONS

This meta-analysis showed that ganciclovir significantly improved the prognosis of glioma patients. Therefore, we suggest that more cases of ganciclovir as a glioma treatment can be conducted, or a large clinical trial can be designed.

The promoting effect and mechanism of MAD2L2 on stemness maintenance and malignant progression in glioma

BACKGROUND

Glioblastoma, the most common primary malignant tumor of the brain, is associated with poor prognosis. Glioblastoma cells exhibit high proliferative and invasive properties, and glioblastoma stem cells (GSCs) have been shown to play a crucial role in the malignant behavior of glioblastoma cells. This study aims to investigate the molecular mechanisms involved in GSCs maintenance and malignant progression.

METHODS

Bioinformatics analysis was performed based on data from public databases to explore the expression profile of Mitotic arrest deficient 2 like 2 (MAD2L2) and its potential function in glioma. The impact of MAD2L2 on glioblastoma cell behaviors was assessed through cell viability assays (CCK8), colony formation assays, 5-Ethynyl-2'-deoxyuridine (EDU) incorporation assays, scratch assays, and transwell migration/invasion assays. The findings from in vitro experiments were further validated in vivo using xenograft tumor model. GSCs were isolated from the U87 and LN229 cell lines through flow cytometry and the stemness characteristics were verified by immunofluorescence staining. The sphere-forming ability of GSCs was examined using the stem cell sphere formation assay. Bioinformatics methods were conducted to identified the potential downstream target genes of MAD2L2, followed by in vitro experimental validation. Furthermore, potential upstream transcription factors that regulate MAD2L2 expression were confirmed through chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays.

RESULTS

The MAD2L2 exhibited high expression in glioblastoma samples and showed significant correlation with patient prognosis. In vitro and in vivo experiments confirmed that silencing of MAD2L2 led to decreased proliferation, invasion, and migration capabilities of glioblastoma cells, while decreasing stemness characteristics of glioblastoma stem cells. Conversely, overexpression of MAD2L2 enhanced these malignant behaviors. Further investigation revealed that MYC proto-oncogene (c-MYC) mediated the functional role of MAD2L2 in glioblastoma, which was further validated through a rescue experiment. Moreover, using dual-luciferase reporter gene assays and ChIP assays determined that the upstream transcription factor E2F-1 regulated the expression of MAD2L2.

CONCLUSION

Our study elucidated the role of MAD2L2 in maintaining glioblastoma stemness and promoting malignant behaviors through the regulation of c-MYC, suggesting its potential as a therapeutic target.

Design, synthesis and evaluation of novel pyrimidinylaminothiophene derivatives as FGFR1 inhibitors against human glioblastoma multiforme

Vascular endothelial growth factor receptors (VEGFRs) have emerged as the most promising anti-angiogenic therapeutic targets for the treatment of recurrent glioblastomas (GBM). However, anti-VEGF treatments led to the high proportion of non-responder patients or non lasting clinical response and the tumor progression to the greater malignant stage. To overcome these problems, there is an utmost need to develop innovative anti-angiogenic therapies. In this study, we report the development of a series of new FGFR1 inhibitors. Among them, compound 4i was able to potently inhibit FGFR1 kinase activities both in vitro and in vivo. This compound displayed strong anti-angiogenic activity in HUVECs and anti-tumor growth and anti-invasion effects in U-87MG cell line. These results emphasize the importance of FGFR1-mediated signaling pathways in GBM and reveal that pharmacological inhibition of FGFR1 can enhance the anti-tumoral, anti-angiogenic and anti-metastatic efficiency against GBM. These data support targeting of FGFR1 as a novel anti-angiogenic strategy and highlight the potential of compound 4i as a promising anti-angiogenic and anti-metastatic candidate for GBM therapy.

Preclinical Models and Technologies in Glioblastoma Research: Evolution, Current State, and Future Avenues

Glioblastoma is the most common malignant primary central nervous system tumor and one of the most debilitating cancers. The prognosis of patients with glioblastoma remains poor, and the management of this tumor, both in its primary and recurrent forms, remains suboptimal. Despite the tremendous efforts that are being put forward by the research community to discover novel efficacious therapeutic agents and modalities, no major paradigm shifts have been established in the field in the last decade. However, this does not mirror the abundance of relevant findings and discoveries made in preclinical glioblastoma research. Hence, developing and utilizing appropriate preclinical models that faithfully recapitulate the characteristics and behavior of human glioblastoma is of utmost importance. Herein, we offer a holistic picture of the evolution of preclinical models of glioblastoma. We further elaborate on the commonly used in vitro and vivo models, delving into their development, favorable characteristics, shortcomings, and areas of potential improvement, which aids researchers in designing future experiments and utilizing the most suitable models. Additionally, this review explores progress in the fields of humanized and immunotolerant mouse models, genetically engineered animal models, 3D in vitro models, and microfluidics and highlights promising avenues for the future of preclinical glioblastoma research.