Glioblastoma: from molecular pathology to targeted treatment

Diversity of metabolic features and relevance to clinical subtypes of gliomas

Gliomas carry a dismal prognosis and have proven difficult to treat. Current treatments and efforts to target individual signaling pathways have failed. This is thought to be due to genetic and epigenetic heterogeneity and resistance. Therefore, interest has grown in developing a deeper understanding of the metabolic alterations that represent drivers and dependencies in gliomas. Therapies that target glioma-specific metabolic dependencies overcome the challenges of disease heterogeneity. Here, we present the diverse metabolic features of each current clinical subtype of glioma. We believe that this approach will enable the development of novel strategies to specifically target the various clinical and molecular subtypes of glioma using these metabolic features.

A rare case of gliosarcoma: Comprehensive radiological, histopathological, and clinical insights into diagnosis and management

Gliosarcoma is a rare and aggressive variant of glioblastoma, characterized by a biphasic histological pattern consisting of both glial and mesenchymal components. This case report describes the clinical presentation, radiological findings, surgical management, and histopathological analysis of gliosarcoma in a 30-year-old female. The patient presented with a 10-day history of right-sided headache and recurrent vomiting. Neurological examination was unremarkable, and vital signs were stable. Magnetic resonance imaging (MRI) revealed a heterogeneously enhancing mass lesion involving the right parietal region and the splenium of the corpus callosum, crossing the midline and causing significant ventricular effacement. Imaging features included heterogeneously hypointense signals on T1-weighted imaging, hyperintense signals on T2/FLAIR, areas of blooming on susceptibility-weighted imaging, and restricted diffusion on diffusion-weighted imaging, suggestive of a high-grade glial tumor. The patient underwent surgical resection, and histopathological examination confirmed gliosarcoma. The tumor exhibited a biphasic pattern comprising glial and sarcomatous elements. This case emphasizes the diagnostic challenges associated with gliosarcoma, where radiological features often mimic glioblastoma, necessitating histopathological confirmation. Gliosarcoma's aggressive nature poses significant therapeutic challenges, with treatment strategies involving surgical resection followed by adjuvant radiotherapy and chemotherapy. This report highlights the importance of integrating clinical, radiological, and histopathological findings to achieve an accurate diagnosis and optimize treatment outcomes. It underscores the need for early recognition and a multidisciplinary approach to managing rare central nervous system tumors like gliosarcoma. Further research into advanced therapeutic strategies is warranted to improve the prognosis for such patients.

Olig1/2 Drive Astrocytic Glioblastoma Proliferation Through Transcriptional Co-Regulation of Various Cyclins

As the most aggressive primary brain tumor, glioblastoma (GBM) is considered incurable due to its molecular heterogeneity and therapy resistance. Identifying key regulatory factors in GBM is critical for developing effective therapeutic strategies. Based on the analysis of TCGA data, we confirmed a robust co-expression and correlation of OLIG1 and OLIG2 in human GBM. However, their roles in the astrocytic GBM subtype remain unclear. In this study, we first establish an astrocytic-featured GBM mouse model by introducing PiggyBac-driven hEGFRvIII plasmids and demonstrate that both OLIG1 and OLIG2 are highly expressed within this context. Next, using CRISPR/Cas9 technology to knockout Olig1/2, we found that astrocyte differentiation markers such as GFAP, SOX9, and HOPX were preserved, but tumor cell proliferation was significantly diminished. Mechanistically, CUT&Tag-seq revealed that OLIG1/2 directly binds to the promoter region of various cyclins (Cdk4, Ccne2, Ccnd3, and Ccnd1), where an enrichment of the active histone marker H3K4me3 was observed, indicating transcriptional activation of the genes. Notably, Olig1/2 knockout did not suppress tumor initiation or migration, suggesting that their primary role is to amplify proliferation rather than to drive tumorigenesis. This study defines Olig1 and Olig2 as master regulators of GBM proliferation through various cyclins, thereby offering a novel therapeutic target.

Diagnostics of brain tumor in the early stage: current status and future perspectives

Early diagnosis of brain tumors is challenging due to their complexity and delicate structure. Conventional imaging techniques like MRI, CT, and PET are unable to provide detailed visualization of early-stage brain tumors. Early-stage detection of brain tumors is vital for enhancing patient outcomes and survival rates. So far, several scientists have dedicated their efforts to innovating advanced diagnostic probes to efficiently cross the BBB and selectively target brain tumors for optimal imaging. The integration of these techniques presents a viable pathway for non-invasive, accurate, and early-stage tumor identification. Herein, we provide a timely update on the various imaging probes and potential challenges for the diagnosis of early-stage brain tumors. Furthermore, this review highlights the significance of integrating advanced imaging probes for improving the early detection of brain tumors, ultimately enhancing treatment outcomes. Hopefully, this review will stimulate the interest of researchers to accelerate the development of new imaging probes and even their clinical translation for improving the early diagnosis of brain tumors.

Targeting PGM3 abolishes SREBP-1 activation-hexosamine synthesis feedback regulation to effectively suppress brain tumor growth

Elevated hexosamine biosynthesis fuels tumor growth by facilitating protein and lipid glycosylation. But which enzyme in this pathway is better to serve as an antitumor target remains unclear. Here, we revealed that targeting GFAT1, the rate-limiting enzyme in hexosamine synthesis, exhibits limited inhibitory effects on glioblastoma (GBM), the most lethal brain tumor. This outcome is due to the compensation of NAGK-mediated hexosamine salvage pathway. Unexpectedly, inhibiting PGM3, which controls the flux of both de novo hexosamine synthesis and salvage pathways, down-regulates the expression of other enzymes in this pathway and suppresses SREBP-1, a critical lipogenic transcription factor, effectively inhibiting GBM growth. Unexpectedly, SREBP-1 transcriptionally up-regulates the expression of hexosamine synthesis enzymes, while inhibition of these enzymes in turn down-regulates SREBP-1 activation via reducing N-glycosylation of its transporter, SCAP. Our study identified PGM3 as a promising target for treating GBM. Its inhibition disrupts the SREBP-1 activation-hexosamine synthesis positive feedback regulation to effectively eliminate GBM cells.

Lipid metabolism: the potential therapeutic targets in glioblastoma

Glioblastoma is a highly malignant tumor of the central nervous system with a high mortality rate. The mechanisms driving glioblastoma onset and progression are complex, posing substantial challenges for developing precise therapeutic interventions to improve patient survival. Over a century ago, the discovery of the Warburg effect underscored the importance of abnormal glycolysis in tumors, marking a pivotal moment in cancer research. Subsequent studies have identified mitochondrial energy conversion as a fundamental driver of tumor growth. Recently, lipid metabolism has emerged as a critical factor in cancer cell survival, providing an alternative energy source. Research has shown that lipid metabolism is reprogrammed in glioblastoma, playing a vital role in shaping the biological behavior of tumor cells. In this review, we aim to elucidate the impact of lipid metabolism on glioblastoma tumorigenesis and explore potential therapeutic targets. Additionally, we provide insights into the regulatory mechanisms that govern lipid metabolism, emphasizing the critical roles of key genes and regulators involved in this essential metabolic process.

NUP98-p65 complex regulates DNA repair to maintain glioblastoma stem cells

The nuclear pore complex (NPC) is an evolutionarily conserved structure that maintains the traffic between the nucleus and cytoplasm. Here, we profiled the expression of nucleoporins (NUPs) in glioblastoma stem cells (GSCs) and found that NUP98 promoted GSC maintenance and therapeutic resistance. GSCs preferentially expressed NUP98, which is essential for GSC tumorigenesis in vitro and in vivo. RNA sequencing demonstrated that NUP98 regulated the expression of key DNA damage and repair pathways. NUP98 formed a complex with transcription factor p65 to directly activate genes involved in homologous repair. Attenuation of NUP98 or p65 expression induced unrepaired intrinsic DNA damage and sensitized GSC to ionizing radiation. Clinically, overexpression of NUP98 informs poor clinical outcome among glioblastoma (GBM) patients. Collectively, our results demonstrate that NUP98-p65 represents a novel node in the regulation of DNA repair, suggesting a therapeutic strategy with potential clinical benefits for GBM patients.

LRRC8A-containing anion channels promote glioblastoma proliferation via a WNK1/mTORC2-dependent mechanism

Leucine-rich repeat-containing protein 8A (LRRC8A) is the essential subunit of ubiquitous volume-regulated anion channels (VRACs). LRCC8A is overexpressed in several cancers and promotes negative survival outcomes via a poorly defined mechanism. Here, we explored the role of LRRC8A and VRACs in the progression of glioblastoma (GBM), the most common and deadly primary brain tumor. We found that, as compared to healthy controls, LRRC8A mRNA was strongly upregulated in surgical GBM specimens, patient-derived GBM cell lines, and GBM datasets from The Cancer Genome Atlas (TCGA). Our in-silico analysis indicated that patients belonging to the lowest LRRC8A expression quartile demonstrated a trend for extended life expectancy. In patient-derived GBM cultures, siRNA-driven LRRC8A knockdown reduced cell proliferation and additionally decreased intracellular chloride levels and inhibited activity of mTOR complex 2. The antiproliferative effect of LRRC8A downregulation was recapitulated with a pharmacological inhibitor of VRAC. Our ensuing biochemical and molecular biology analyses established that the LRRC8A-containing VRACs facilitate GBM proliferation via a new mechanism involving non-enzymatic actions of the chloride-sensitive protein kinase WNK1. Accordingly, the chloride-bound WNK1 stimulates mTORC2 and the mTORC2-dependent protein kinases AKT and SGK, which promote proliferation. These findings establish the new mTORC2-centric axis for VRAC dependent regulation of cellular functions and uncover potential targets for GBM intervention.

Unlocking the code: The role of molecular and genetic profiling in revolutionizing glioblastoma treatment

Glioblastoma (GBM) is the most aggressive primary brain cancer, characterized by profound molecular and cellular heterogeneity, which contributes to its resistance to conventional therapies and poor prognosis. Despite multimodal treatments including surgical resection, radiation, and chemotherapy, median survival remains approximately 15 months. Recent advances in molecular and genetic profiling have elucidated key genetic alterations and molecular subtypes of GBM, such as EGFR amplification, PTEN and ATRX loss, and TP53 alterations, which have significant prognostic and therapeutic implications. These discoveries have spurred the development of targeted therapies aimed at disrupting aberrant signaling pathways like RTK/RAS/PI3K and TP53. However, treatment resistance remains a formidable challenge, driven by tumor heterogeneity, the complex tumor microenvironment (TME), and intrinsic adaptive mechanisms. Emerging therapeutic approaches aim to address these challenges, including the use of immunotherapies such as immune checkpoint inhibitors and CAR T-cell therapies, which target specific tumor antigens but face hurdles due to the immunosuppressive TME. Additionally, novel strategies like biopolymer-based interstitial therapies, focused ultrasound for blood-brain barrier disruption, and nanoparticle-based drug delivery systems show promise in enhancing the efficacy and precision of GBM treatments. This review explores the evolving landscape of GBM therapy, emphasizing the importance of personalized medicine through molecular profiling, the potential of combination therapies, and the need for innovative approaches to overcome therapeutic resistance. Continued research into GBM's biology and treatment modalities offers hope for improving patient outcomes.

Identification of critical biomarkers and immune landscape patterns in glioma based on multi-database

PURPOSE

Glioma is the most prevalent tumor of the central nervous system. The poor clinical outcomes and limited therapeutic efficacy underscore the urgent need for early diagnosis and an optimized prognostic approach for glioma. Therefore, the aim of this study was to identify sensitive biomarkers for glioma.

PATIENTS AND METHODS

Differentially expressed genes (DEGs) of glioma were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The potential biomarkers were identified using weighted gene co-expression network analysis (WGCNA) and least absolute shrinkage and selection operator (LASSO) regression. The prognostic ability of the potential biomarkers was evaluated by Cox regression and survival curve. CellMiner was used to access the correlation between the expression of potential biomarkers and anticancer drug sensitivity. We then explored the association of potential biomarkers and tumor immune infiltration by single-sample GSEA (ssGSEA) and CIBERSORT. Immune staining in glioma patient samples and cell experiments of potential biomarkers further verified their expression and function.

RESULTS

Ultimately, we identified three potential biomarkers: SLC8A2, ATP2B3, and SRCIN1. These 3 genes were found significantly correlated with clinicopathological features (age, WHO grade, IDH mutation status, 1p19q codeletion status). Furthermore, the overall survival (OS), disease-specific survival (DSS), and progression-free survival (PFS) were found to be positively correlated with high expression of these 3 potential biomarkers. Besides, there was a substantial relationship between the sensitivity of anticancer drugs and these biomarkers expression. More importantly, the negative association between the 3 genes with most tumor immune cells was also established. Moreover, the decreased expression of the biomarkers was also verified in glioma patient samples. Finally, we confirmed that these 3 genes might promotes glioma proliferation and migration in vitro.

CONCLUSION

SLC8A2, ATP2B3, and SRCIN1 were identified as underlying biomarkers for glioma associated with prognosis assessments and personal immunotherapy.

Mitochondrial transcription elongation factor TEFM promotes malignant progression of gliomas

Gliomas are the most common tumors of the central nervous system, with glioblastoma (GBM) being particularly aggressive and fatal. Current treatments for GBM, including surgery and chemotherapy, are limited by tumor aggressiveness and the blood-brain barrier. Therefore, understanding the molecular mechanisms driving GBM growth is essential. Mitochondria, key players in cellular energy production, have been implicated in cancer development. In this study, we investigated the expression of mitochondrial transcription elongation factor (TEFM) in gliomas and its potential role in tumor progression. Analysis of data from The Cancer Genome Atlas (TCGA) revealed that TEFM transcript levels were significantly higher in glioma tissues compared to adjacent normal tissues. High TEFM expression was associated with poor survival outcomes in glioma patients. Furthermore, TEFM was notably upregulated in glioma tissue and in primary glioma cells derived from local patients, while its expression was relatively low in normal tissues and astrocytes. Silencing or knockout of TEFM significantly inhibited glioma cell growth, proliferation, clonogenicity, migration, and invasion, while inducing apoptosis and activating caspases. In contrast, ectopic overexpression of TEFM promoted tumorigenic activity, enhancing the malignant behavior of glioma cells. Co-expression analysis identified a strong correlation between TEFM and the epithelial-mesenchymal transition (EMT) pathway in gliomas. Notably, the expression of EMT markers, such as N-cadherin and Vimentin, decreased upon TEFM knockdown or knockout. Additionally, TEFM depletion impaired mitochondrial function, disrupting the mitochondrial respiratory chain in glioma cells. In vivo experiments demonstrated that TEFM knockout effectively suppressed the growth of subcutaneous glioma xenografts in nude mice. Collectively, these findings highlight the critical role of TEFM in GBM growth and invasion, suggesting that it could serve as a promising therapeutic target for glioma treatment.

Targeted reprogramming of tumor-associated macrophages for overcoming glioblastoma resistance to chemotherapy and immunotherapy

The resistance of glioblastoma multiforme (GBM) to standard chemotherapy is primarily attributed to the existence of tumor-associated macrophages (TAMs) in the GBM microenvironment, particularly the anti-inflammatory M2 phenotype. Targeted modulation of M2-TAMs is emerging as a promising strategy to enhance chemotherapeutic efficacy. However, combination TAM-targeted therapy with chemotherapy faces substantial challenges, notably in terms of delivery efficiency and targeting specificity. In this study, we designed a pH-responsive hierarchical brain-targeting micelleplex loaded with temozolomide (TMZ) and resiquimod (R848) for combination chemo-immunotherapy against GBM. This delivery system, termed PCPA&PPM@TR, features a primary Angiopep-2 decoration on the outer layer via a pH-cleavable linker and a secondary mannose analogue (MAN) on the middle layer. This pH-responsive hierarchical targeting strategy enables effective BBB permeability while simultaneous GBM- and TAMs-targeting delivery. GBM-targeted delivery of TMZ induces alkylation and triggers an anti-GBM immune response. Concurrently, TAM-targeted delivery of R848 reprograms their phenotype from M2 to pro-inflammatory M1, thereby diminishing GBM resistance to TMZ and amplifying the immune response. In vivo studies demonstrated that targeted modulation of TAMs using PCPA&PPM@TR significantly enhanced anti-GBM efficacy. In summary, this study proposes a promising brain-targeting delivery system for the targeted modulation of TAMs to combat GBM.

Integrated molecular and functional characterization of the intrinsic apoptotic machinery identifies therapeutic vulnerabilities in glioma

Genomic profiling often fails to predict therapeutic outcomes in cancer. This failure is, in part, due to a myriad of genetic alterations and the plasticity of cancer signaling networks. Functional profiling, which ascertains signaling dynamics, is an alternative method to anticipate drug responses. It is unclear whether integrating genomic and functional features of solid tumours can provide unique insight into therapeutic vulnerabilities. We perform combined molecular and functional characterization, via BH3 profiling of the intrinsic apoptotic machinery, in glioma patient samples and derivative models. We identify that standard-of-care therapy rapidly rewires apoptotic signaling in a genotype-specific manner, revealing targetable apoptotic vulnerabilities in gliomas containing specific molecular features (e.g., TP53 WT). However, integration of BH3 profiling reveals high mitochondrial priming is also required to induce glioma apoptosis. Accordingly, a machine-learning approach identifies a composite molecular and functional signature that best predicts responses of diverse intracranial glioma models to standard-of-care therapies combined with ABBV-155, a clinical drug targeting intrinsic apoptosis. This work demonstrates how complementary functional and molecular data can robustly predict therapy-induced cell death.

Research progress of drug resistance mechanism of temozolomide in the treatment of glioblastoma

Glioblastoma, the most malignant primary brain tumor among gliomas, is characterized by a low cure rate, high recurrence rate, and invasive growth. Without chemotherapy, the median survival of patients is only 12.1 months. The standard treatment for glioblastoma primarily involves surgical resection, complemented by radiotherapy. Temozolomide (TMZ), a new oral alkylating agent, is currently used as the first-line chemotherapy drug for glioma. However, TMZ treatment only improves median survival by 2 months, largely because of the tumor's ability to develop resistance to the drug. The main mechanism underlying this resistance involves DNA repair processes, such as the action of O6⁃methylguanine DNA methyltransferase (MGMT), which repairs the DNA damage caused by TMZ, and other DNA repair mechanisms including mismatch repair and base excision repair. These mechanisms can effectively repair the DNA damage caused by TMZ, thereby reducing the sensitivity of tumor cells to the drug. This study summarized the recent research progress of TMZ resistance mechanism in glioblastoma, aiming to provide a theoretical basis for the development of new therapies. The mechanisms of glioma resistance to TMZ mainly involves DNA damage repair (as mentioned above), abnormal cell signaling pathways (p53-mediated signaling, reactive oxygen species-mediated signaling, endoplasmic reticulum stress and autophagy-related signaling, receptor tyrosine kinase-related signaling, transforming growth factors, β-mediated signaling pathway, Wnt/β-Catenin signaling pathway), glioma stem cells, tumor microenvironment (hypoxic microenvironment, nano-drug delivery system), epidermal growth factor receptor, and microRNAs.

Oxime Linked Doxorubicin Glycoconjugates Improve the Specific Targeting of Glioblastoma in High-Grade Glioma Therapy

The treatment of glioblastoma (GBM) represents an urgent challenge for public health due to the inability to effectively deliver anticancer agents, such as doxorubicin (DOX), through the blood-brain barrier (BBB). Herein we report the synthesis of two novel DOX glycoconjugates using an oxime linkage that maintained the intercalation capability of the planar anthracycline ring of DOX, as demonstrated by UV-vis and fluorescence experiments in the presence of DNA. The biological effect of DOX glycoconjugates was evaluated in GBM cell lines, showing an enhanced cytotoxic and pro-apoptotic effect of 7 as compared to 4 and to conventional DOX. These data were confirmed in an in vitro coculture BBB model in which DOX glycoconjugate 7 showed high capability to cross a cellular monolayer and exert its cytotoxic effect on GBM cells. The results show that conjugation with glucose may represent a helpful tool to increase chemotherapy effectiveness in poor-responding GBM patients.

Enhancing anti-EGFRvIII CAR T cell therapy against glioblastoma with a paracrine SIRPγ-derived CD47 blocker

A significant challenge for chimeric antigen receptor (CAR) T cell therapy against glioblastoma (GBM) is its immunosuppressive microenvironment, which is densely populated by protumoral glioma-associated microglia and macrophages (GAMs). Myeloid immune checkpoint therapy targeting the CD47-signal regulatory protein alpha (SIRPα) axis induces GAM phagocytic function, but CD47 blockade monotherapy is associated with toxicity and low bioavailability in solid tumors. In this work, we engineer a CAR T cell against epidermal growth factor receptor variant III (EGFRvIII), constitutively secreting a signal regulatory protein gamma-related protein (SGRP) with high affinity to CD47. Anti-EGFRvIII-SGRP CAR T cells eradicate orthotopic EGFRvIII-mosaic GBM in vivo, promoting GAM-mediated tumor cell phagocytosis. In a subcutaneous CD19+ lymphoma mouse model, anti-CD19-SGRP CAR T cell therapy is superior to conventional anti-CD19 CAR T. Thus, combination of CAR and SGRP eliminates bystander tumor cells in a manner that could overcome main mechanisms of CAR T cell therapy resistance, including immune suppression and antigen escape.

Aptamers: ushering in new hopes in targeted glioblastoma therapy

Glioblastoma, a formidable brain cancer, has remained a therapeutic challenge due to its aggressive nature and resistance to conventional treatments. Recent data indicate that aptamers, short synthetic DNA or RNA molecules can be used in anti-cancer therapy due to their better tumour penetration, specific binding affinity, longer retention in tumour sites and their ability to cross the blood-brain barrier. With the ability to modify these oligonucleotides through the selection process, and using rational design to modify them, post-SELEX aptamers offer several advantages in glioblastoma treatment, including precise targeting of cancer cells while sparing healthy tissue. This review discusses the pivotal role of aptamers in glioblastoma therapy and diagnosis, emphasising their potential to enhance treatment efficacy and also highlights recent advancements in aptamer-based therapies which can transform the landscape of glioblastoma treatment, offering renewed hope to patients and clinicians alike.

Deoxyarbutin targets mitochondria to trigger p53-dependent senescence of glioblastoma cells

Cellular senescence is a natural barrier of the transition from premalignant cells to invasive cancer. Pharmacological induction of senescence has been proposed as a possible anticancer strategy. In this study, we found that deoxyarbutin inhibited the growth of glioblastoma (GBM) cells by inducing cellular senescence, independent of tyrosinase expression. Instead, deoxyarbutin induced mitochondrial oxidative stress and damage. These aberrant mitochondria were key to the p53-dependent senescence of GBM cells. Facilitating autophagy or mitigating mitochondrial oxidative stress both suppressed p53 expression and alleviated cellular senescence induced by deoxyarbutin. Thus, our study reveals that deoxyarbutin induces mitochondrial oxidative stress to trigger the p53-dependent senescence of GBM cells. Importantly, deoxyarbutin treatment resulted in accumulation of p53, induction of cellular senescence, and inhibition of tumor growth in a subcutaneous tumor model of mouse. In conclusion, our study reveals that deoxyarbutin has therapeutic potential for GBM by inducing mitochondrial oxidative stress for p53-dependent senescence of GBM cells.

Practical immunomodulatory landscape of glioblastoma multiforme (GBM) therapy

Glioblastoma multiforme (GBM) is the most common harmful high-grade brain tumor with high mortality and low survival rate. Importantly, besides routine diagnostic and therapeutic methods, modern and useful practical techniques are urgently needed for this serious malignancy. Correspondingly, the translational medicine focusing on genetic and epigenetic profiles of glioblastoma, as well as the immune framework and brain microenvironment, based on these challenging findings, indicates that key clinical interventions include immunotherapy, such as immunoassay, oncolytic viral therapy, and chimeric antigen receptor T (CAR T) cell therapy, which are of great importance in both diagnosis and therapy. Relatively, vaccine therapy reflects the untapped confidence to enhance GBM outcomes. Ongoing advances in immunotherapy, which utilizes different methods to regenerate or modify the resistant body for cancer therapy, have revealed serious results with many different problems and difficulties for patients. Safe checkpoint inhibitors, adoptive cellular treatment, cellular and peptide antibodies, and other innovations give researchers an endless cluster of instruments to plan profoundly in personalized medicine and the potential for combination techniques. In this way, antibodies that block immune checkpoints, particularly those that target the program death 1 (PD-1)/PD-1 (PD-L1) ligand pathway, have improved prognosis in a wide range of diseases. However, its use in combination with chemotherapy, radiation therapy, or monotherapy is ineffective in treating GBM. The purpose of this review is to provide an up-to-date overview of the translational elements concentrating on the immunotherapeutic field of GBM alongside describing the molecular mechanism involved in GBM and related signaling pathways, presenting both historical perspectives and future directions underlying basic and clinical practice.

An immune-related gene pair signature predicts the prognosis and immunotherapeutic response in glioblastoma

Background

Glioblastoma (GBM) has the feature of aggressive growth and high rates of recurrence. Immunotherapy was not included in standard therapy for GBM due to lacking the predictive biomarkers. In the present study, we performed an immune-related gene pair (IRGP) signature to predict the prognosis and immunotherapy response of GBM.

Methods

A total of 160 GBM patients from TCGA were included. ssGSEA was conducted to evaluate the immune infiltration level. Univariate Cox, LASSO regression analysis, ROC analysis, and Kaplan-Meier survival analysis were applied to construct and evaluate the risk model. Moreover, the association between immune infiltration and the risk score was assessed. Finally, the expression of immune checkpoints between different risk groups was explored.

Results

According to the normal/tumor, high-/low-immunity group, we identified 125 differentially expressed immune-related genes. Subsequently, a prognostic model including 22 IRGPs was established. The area under the ROC curve to predict 1, 3, and 5-year was 0.811, 0.958, and 0.99 respectively. According to the optimal cut-off value of the 3-year ROC curve, patients were classified into high- and low-risk groups. The Kaplan-Meier analysis result indicated that patients in the low-risk group have longer survival time. The risk score was an independent prognostic predictor (P < 0.001). Moreover, PDCD1 was positively correlated with the risk score (P < 0.01). We also found that patients with high PDCD1 expression had worse survival.

Conclusions

The IRGP signature was built to predict the prognosis of GBM patients. This signature can serve as a tool to predict the response to immunotherapy in GBM.

Mitogen-activated protein kinase kinase kinase 1 facilitates the temozolomide resistance and migration of GBM via the MEK/ERK signalling

Mitogen-Activated Protein Kinase Kinase Kinase 1 (MAP3K1) is overexpressed in gliomas; however, its clinical significance, biological functions, and underlying molecular mechanisms remain unclear. Abnormal overexpression of MAP3K1 in glioma is strongly associated with unfavourable clinicopathological characteristics and disease progression. MAP3K1 could potentially serve as a reliable diagnostic and prognostic biomarker for glioma. MAP3K1 silencing suppressed the migration but had no effect on the proliferation and cell death of Glioblastoma Multiforme (GBM) cells. MAP3K1 knockdown exacerbated the temozolomide (TMZ) induced inhibition of glioma cell proliferation and death of GBM cells. In addition, MAP3K1 knockdown combined with TMZ treatment significantly inhibited the growth and increased cell death in organoids derived from GBM patients. MAP3K1 knockdown reversed TMZ resistance of GBM in intracranial glioma model. In terms of molecular mechanisms, the phosphorylation level of ERK was significantly decreased by MAP3K1 silencing. No significant change in the JNK pathway was found in MAP3K1-silenced GBM cells. Inhibition of ERK phosphorylation suppressed the migration and enhanced the TMZ sensibility of GBM cells. MAP3K1 was correlated with the immune infiltration in glioma. MAP3K1 could facilitate the migration and TMZ resistance of GBM cells through MEK/ERK signalling.

A scientometric analysis of immunotherapies for gliomas: Focus on GBM

Gliomas are the most prevalent primary malignant brain tumors worldwide, with glioblastoma (GBM) being the most common and aggressive type. The standard therapy for GBM has remained unchanged for nearly two decades, with no significant improvement in survival outcomes. Despite several barriers such as the tumor microenvironment (TME) and blood-brain barrier, immunotherapies bring new hope for the treatment of GBM. To better understand the development and progress of immunotherapies in GBM, we made this scientometric analysis of this field. A total of 3753 documents were obtained from the Web of Science Core Collection, with publication years ranging from 1999 to 2022. The Web of Science platform, CiteSpace, and VOS viewer were used to conduct the scientometric analysis. The results of scientometric analysis showed that this field has recently become a popular topic of interest. The United States had the most publications among 89 countries or regions. Keyword analysis indicated significant areas in the field of immunotherapies for GBM, especially TME, immune checkpoint blockades (ICBs), chimeric antigen receptor T (CAR-T) cells, vaccines, and oncolytic viruses (OVs). Overall, we hope that this scientometric analysis can provide insights for researchers and promote the development of this field.

Mapping the evolution and research landscape of ferroptosis-targeted nanomedicine: insights from a scientometric analysis

Objective

Notable progress has been made in "ferroptosis-based nano drug delivery systems (NDDSs)" over the past 11 years. Despite the ongoing absence of a comprehensive scientometric overview and up-to-date scientific mapping research, especially regarding the evolution, critical research pathways, current research landscape, central investigative themes, and future directions.

Methods

Data ranging from 1 January 2012, to 30 November 2023, were obtained from the Web of Science database. A variety of advanced analytical tools were employed for detailed scientometric and visual analyses.

Results

The results show that China significantly led the field, contributing 82.09% of the total publications, thereby largely shaping the research domain. Chen Yu emerged as the most productive author in this field. Notably, the journal ACS Nano had the greatest number of relevant publications. The study identified liver neoplasms, pancreatic neoplasms, gliomas, neoplasm metastases, and melanomas as the top five crucial disorders in this research area.

Conclusion

This research provides a comprehensive scientometric assessment, enhancing our understanding of NDDSs focused on ferroptosis. Consequently, it enables rapid access to essential information and facilitates the extraction of novel ideas in the field of ferroptotic nanomedicine for both experienced and emerging researchers.

Combinatorial targeting of glutamine metabolism and lysosomal-based lipid metabolism effectively suppresses glioblastoma

Antipsychotic drugs have been shown to have antitumor effects but have had limited potency in the clinic. Here, we unveil that pimozide inhibits lysosome hydrolytic function to suppress fatty acid and cholesterol release in glioblastoma (GBM), the most lethal brain tumor. Unexpectedly, GBM develops resistance to pimozide by boosting glutamine consumption and lipogenesis. These elevations are driven by SREBP-1, which we find upregulates the expression of ASCT2, a key glutamine transporter. Glutamine, in turn, intensifies SREBP-1 activation through the release of ammonia, creating a feedforward loop that amplifies both glutamine metabolism and lipid synthesis, leading to drug resistance. Disrupting this loop via pharmacological targeting of ASCT2 or glutaminase, in combination with pimozide, induces remarkable mitochondrial damage and oxidative stress, leading to GBM cell death in vitro and in vivo. Our findings underscore the promising therapeutic potential of effectively targeting GBM by combining glutamine metabolism inhibition with lysosome suppression.

Structural insights into the role and targeting of EGFRvIII

The epidermal growth factor receptor (EGFR) is a well-known oncogenic driver in lung and other cancers. In glioblastoma multiforme (GBM), the EGFR deletion variant III (EGFRvIII) is frequently found alongside EGFR amplification. Agents targeting the EGFR axis have shown limited clinical benefits in GBM and the role of EGFRvIII in GBM is poorly understood. To shed light on the role of EGFRvIII and its potential as a therapeutic target, we determined X-ray crystal structures of a monomeric EGFRvIII extracellular region (ECR). The EGFRvIII ECR resembles the unliganded conformation of EGFR, including the orientation of the C-terminal region of domain II. Domain II is mostly disordered, but the ECR structure is compact. We selected a nanobody with preferential binding to EGFRvIII relative to EGFR and structurally defined an epitope on domain IV that is occluded in the unliganded intact EGFR. These findings suggest new avenues for EGFRvIII targeting in GBM.

The functions of exosomes targeting astrocytes and astrocyte-derived exosomes targeting other cell types

Astrocytes are the most abundant glial cells in the central nervous system; they participate in crucial biological processes, maintain brain structure, and regulate nervous system function. Exosomes are cell-derived extracellular vesicles containing various bioactive molecules including proteins, peptides, nucleotides, and lipids secreted from their cellular sources. Increasing evidence shows that exosomes participate in a communication network in the nervous system, in which astrocyte-derived exosomes play important roles. In this review, we have summarized the effects of exosomes targeting astrocytes and the astrocyte-derived exosomes targeting other cell types in the central nervous system. We also discuss the potential research directions of the exosome-based communication network in the nervous system. The exosome-based intercellular communication focused on astrocytes is of great significance to the biological and/or pathological processes in different conditions in the brain. New strategies may be developed for the diagnosis and treatment of neurological disorders by focusing on astrocytes as the central cells and utilizing exosomes as communication mediators.

m6A-Mediated Upregulation of lncRNA CHASERR Promotes the Progression of Glioma by Modulating the miR-6893-3p/TRIM14 Axis

Long noncoding RNAs (lncRNAs) play crucial roles in tumor progression and are dysregulated in glioma. However, the functional roles of lncRNAs in glioma remain largely unknown. In this study, we utilized the TCGA (the Cancer Genome Atlas database) and GEPIA2 (Gene Expression Profiling Interactive Analysis 2) databases and observed the overexpression of lncRNA CHASERR in glioma tissues. We subsequently investigated this phenomenon in glioma cell lines. The effects of lncRNA CHASERR on glioma proliferation, migration, and invasion were analyzed using in vitro and in vivo experiments. Additionally, the regulatory mechanisms among PTEN/p-Akt/mTOR and Wnt/β-catenin, lncRNA CHASERR, Micro-RNA-6893-3p(miR-6893-3p), and tripartite motif containing14 (TRIM14) were investigated via bioinformatics analyses, quantitative real-time PCR (qRT-PCR), western blot (WB), RNA immunoprecipitation (RIP), dual luciferase reporter assay, fluorescence in situ hybridization (FISH), and RNA sequencing assays. RIP and RT-qRCR were used to analyze the regulatory effect of N6-methyladenosine(m6A) on the aberrantly expressed lncRNA CHASERR. High lncRNA CHASERR expression was observed in glioma tissues and was associated with unfavorable prognosis in glioma patients. Further functional assays showed that lncRNA CHASERR regulates glioma growth and metastasis in vitro and in vivo. Mechanistically, lncRNA CHASERR sponged miR-6893-3p to upregulate TRIM14 expression, thereby facilitating glioma progression. Additionally, the activation of PTEN/p-Akt/mTOR and Wnt/β-catenin pathways by lncRNA CHASERR, miR-6893-3p, and TRIM14 was found to regulate glioma progression. Moreover, the upregulation of lncRNA CHASERR was observed in response to N6-methyladenosine modification, which was facilitated by METTL3/YTHDF1-mediated RNA transcripts. This study elucidates the m6A/lncRNACHASERR/miR-6893-3p/TRIM14 pathway that contributes to glioma progression and underscores the potential of lncRNA CHASERR as a novel prognostic indicator and therapeutic target for glioma.

The effects of the combination therapy of chemotherapy drugs on the fluctuations of genes involved in the TLR signaling pathway in glioblastoma multiforme therapy

One of the most lethal and aggressive types of malignancies with a high mortality rate and poor response to treatment is glioblastoma multiforme (GBM). This means that modernizing the medications used in chemotherapy, in addition to medicines licensed for use in other illnesses and chosen using a rationale process, can be beneficial in treating this illness. Meaningly, drug combination therapy with chemical or herbal originations or implanting a drug wafer in tumors to control angiogenesis is of great importance. Importantly, the primary therapeutic hurdles in GBM are the development of angiogenesis and the blood-brain barrier (BBB), which keeps medications from getting to the tumor. This malignancy can be controlled if the drug's passage through the BBB and the VEGF (vascular endothelial growth factor), which promotes angiogenesis, are inhibited. In this way, the effect of combination therapy on the genes of different main signaling pathways like TLRs may be indicated as an impressive therapeutic strategy for treating GBM. This article aims to discuss the effects of chemotherapeutic drugs on the expression of various genes and associated translational factors involved in the TLR signaling pathway.

Bystander Effects, Pharmacokinetics, and Linker-Payload Stability of EGFR-Targeting Antibody-Drug Conjugates Losatuxizumab Vedotin and Depatux-M in Glioblastoma Models

PURPOSE

Antibody-drug conjugates (ADC) are targeted therapies with robust efficacy in solid cancers, and there is intense interest in using EGFR-specific ADCs to target EGFR-amplified glioblastoma (GBM). Given GBM's molecular heterogeneity, the bystander activity of ADCs may be important for determining treatment efficacy. In this study, the activity and toxicity of two EGFR-targeted ADCs with similar auristatin toxins, Losatuxizumab vedotin (ABBV-221) and Depatuxizumab mafodotin (Depatux-M), were compared in GBM patient-derived xenografts (PDX) and normal murine brain following direct infusion by convection-enhanced delivery (CED).

EXPERIMENTAL DESIGN

EGFRviii-amplified and non-amplified GBM PDXs were used to determine in vitro cytotoxicity, in vivo efficacy, and bystander activities of ABBV-221 and Depatux-M. Nontumor-bearing mice were used to evaluate the pharmacokinetics (PK) and toxicity of ADCs using LC-MS/MS and immunohistochemistry.

RESULTS

CED improved intracranial efficacy of Depatux-M and ABBV-221 in three EGFRviii-amplified GBM PDX models (Median survival: 125 to >300 days vs. 20-49 days with isotype control AB095). Both ADCs had comparable in vitro and in vivo efficacy. However, neuronal toxicity and CD68+ microglia/macrophage infiltration were significantly higher in brains infused with ABBV-221 with the cell-permeable monomethyl auristatin E (MMAE), compared with Depatux-M with the cell-impermeant monomethyl auristatin F. CED infusion of ABBV-221 into the brain or incubation of ABBV-221 with normal brain homogenate resulted in a significant release of MMAE, consistent with linker instability in the brain microenvironment.

CONCLUSIONS

EGFR-targeting ADCs are promising therapeutic options for GBM when delivered intratumorally by CED. However, the linker and payload for the ADC must be carefully considered to maximize the therapeutic window.

METTL1-modulated LSM14A facilitates proliferation and migration in glioblastoma via the stabilization of DDX5

Glioblastoma (GBM) is characterized by aggressive growth, invasiveness, and poor prognosis. Elucidating the molecular mechanisms underlying GBM is crucial. This study explores the role of Sm-like protein 14 homolog A (LSM14A) in GBM. Bioinformatics and clinical tissue samples analysis demonstrated that overexpression of LSM14A in GBM correlates with poorer prognosis. CCK8, EdU, colony formation, and transwell assays revealed that LSM14A promotes proliferation, migration, and invasion in GBM in vitro. In vivo mouse xenograft models confirmed the results of the in vitro experiments. The mechanism of LSM14A modulating GBM cell proliferation was investigated using mass spectrometry, co-immunoprecipitation (coIP), protein half-life, and methylated RNA immunoprecipitation (MeRIP) analyses. The findings indicate that during the G1/S phase, LSM14A stabilizes DDX5 in the cytoplasm, regulating CDK4 and P21 levels. Furthermore, METTL1 modulates LSM14A expression via mRNA m7G methylation. Altogether, our work highlights the METTL1-LSM14A-DDX5 pathway as a potential therapeutic target in GBM.

Recurrent Glioblastoma-Molecular Underpinnings and Evolving Treatment Paradigms

Glioblastoma is the most common and lethal central nervous system malignancy with a median survival after progression of only 6-9 months. Major biochemical mechanisms implicated in glioblastoma recurrence include aberrant molecular pathways, a recurrence-inducing tumor microenvironment, and epigenetic modifications. Contemporary standard-of-care (surgery, radiation, chemotherapy, and tumor treating fields) helps to control the primary tumor but rarely prevents relapse. Cytoreductive treatment such as surgery has shown benefits in recurrent glioblastoma; however, its use remains controversial. Several innovative treatments are emerging for recurrent glioblastoma, including checkpoint inhibitors, chimeric antigen receptor T cell therapy, oncolytic virotherapy, nanoparticle delivery, laser interstitial thermal therapy, and photodynamic therapy. This review seeks to provide readers with an overview of (1) recent discoveries in the molecular basis of recurrence; (2) the role of surgery in treating recurrence; and (3) novel treatment paradigms emerging for recurrent glioblastoma.

Extended dosing (12 cycles) vs conventional dosing (6 cycles) of adjuvant temozolomide in adults with newly diagnosed high-grade gliomas: a randomized, single-blind, two-arm, parallel-group controlled trial

Purpose

Maximum safe surgical resection followed by adjuvant chemoradiation and temozolomide chemotherapy is the current standard of care in the management of newly diagnosed high grade glioma. However, there are controversies about the optimal number of adjuvant temozolomide cycles. This study aimed to compare the survival benefits of 12 cycles against 6 cycles of adjuvant temozolomide adults with newly diagnosed high grade gliomas.

Methods

Adult patients with newly diagnosed high grade gliomas, and a Karnofsky performance status>60%, were randomized to receive either 6 cycles or 12 cycles of adjuvant temozolomide. Patients were followed-up for assessment of overall survival (OS) and progression-free survival (PFS) by brain MRI every 3 months within the first year after treatment and then every six months.

Results

A total of 100 patients (6 cycles, 50; 12 cycles, 50) were entered. The rate of treatment completion in 6 cycles and 12 cycles groups were 91.3% and 55.1%, respectively. With a median follow-up of 26 months, the 12-, 24-, 36-, and 48-month OS rates in 6 cycles and 12 cycles groups were 81.3% vs 78.8%, 58.3% vs 49.8%, 47.6% vs 34.1%, and 47.6% vs 31.5%, respectively (p-value=.19). Median OS of 6 cycles and 12 cycles groups were 35 months (95% confidence interval (CI), 11.0 to 58.9) and 23 months (95%CI, 16.9 to 29.0). The 12-, 24-, 36-, and 48- month PFS rates in 6 cycles and 12 cycles groups were 70.8% vs 56.9%, 39.5% and 32.7%, 27.1% vs 28.8%, and 21.1% vs 28.8%, respectively (p=.88). The Median PFS of 6 cycles and 12 cycles groups was 18 months (95% CI, 14.8 to 21.1) and 16 (95% CI, 11.0 to 20.9) months.

Conclusion

Patients with newly diagnosed high grade gliomas treated with adjuvant temozolomide after maximum safe surgical resection and adjuvant chemoradiation do not benefit from extended adjuvant temozolomide beyond 6 cycles.

Trial registration

Prospectively registered with the Iranian Registry of Clinical Trials: IRCT20160706028815N3. Date registered: 18/03/14.

N6-isopentenyladenosine inhibits aerobic glycolysis in glioblastoma cells by targeting PKM2 expression and activity

Glioblastoma (GBM) is a primary tumor in the central nervous system with poor prognosis. It exhibits elevated glucose uptake and lactate production. This metabolic state of aerobic glycolysis is known as the Warburg effect. N6-isopentenyladenosine (iPA), a natural cytokine modified with an isopentenyl moiety derived from the mevalonate pathway, has well-established anti-tumor activity. It inhibits cell proliferation in glioma cells, inducing cell death by apoptosis and/or necroptosis. In the present study, we found that iPA inhibits aerobic glycolysis in unmodified U87MG cells and in the same cell line engineered to over-express wild-type epidermal growth factor receptor (EGFR) or EGFR variant III (vIII), as well as in a primary GBM4 patient-derived cell line. The detection of glycolysis showed that iPA treatment suppressed ATP and lactate production. We also evaluated the response of iPA treatment in normal human astrocyte primary cells, healthy counterpart cells of the brain. Aerobic glycolysis in treated normal human astrocyte cells did not show significant changes compared to GBM cells. To determine the mechanism of iPA action on aerobic glycolysis, we investigated the expression of certain enzymes involved in this metabolic pathway. We observed that iPA reduced the expression of pyruvate kinase M2 (PKM2), which plays a key role in the regulation of aerobic glycolysis, promoting tumor cell proliferation. The reduction of PKM2 expression is a result of the inhibition of the inhibitor of nuclear factor kappa-B kinase subunit, beta/nuclear factor-kappa B pathway upon iPA treatment. In conclusion, these experimental results show that iPA may inhibit aerobic glycolysis of GBM in stabilized cell lines and primary GBM cells by targeting the expression and activity of PKM2.

Antitumoral Activity of the Universal Methyl Donor S-Adenosylmethionine in Glioblastoma Cells

Glioblastoma (GBM), the most frequent and lethal brain cancer in adults, is characterized by short survival times and high mortality rates. Due to the resistance of GBM cells to conventional therapeutic treatments, scientific interest is focusing on the search for alternative and efficient adjuvant treatments. S-Adenosylmethionine (AdoMet), the well-studied physiological methyl donor, has emerged as a promising anticancer compound and a modulator of multiple cancer-related signaling pathways. We report here for the first time that AdoMet selectively inhibited the viability and proliferation of U87MG, U343MG, and U251MG GBM cells. In these cell lines, AdoMet induced S and G2/M cell cycle arrest and apoptosis and downregulated the expression and activation of proteins involved in homologous recombination DNA repair, including RAD51, BRCA1, and Chk1. Furthermore, AdoMet was able to maintain DNA in a damaged state, as indicated by the increased γH2AX/H2AX ratio. AdoMet promoted mitotic catastrophe through inhibiting Aurora B kinase expression, phosphorylation, and localization causing GBM cells to undergo mitotic catastrophe-induced death. Finally, AdoMet inhibited DNA repair and induced cell cycle arrest, apoptosis, and mitotic catastrophe in patient-derived GBM cells. In light of these results, AdoMet could be considered a potential adjuvant in GBM therapy.

TMEM64 aggravates the malignant phenotype of glioma by activating the Wnt/β-catenin signaling pathway

Transmembrane protein 64 (TMEM64), a member of the family of transmembrane protein, is an α-helical membrane protein. Its precise role in various types of tumors, including glioma, is unclear. This study used immunohistochemical (IHC) staining, western blotting, and quantitative reverse transcription polymerase chain reaction (qRT-PCR) techniques to show that TMEM64 expression was significantly higher in glioma cells and tissues compared to normal cells and tissues, respectively. Additionally, a correlation between high TMEM64 expression and higher grade as well as a worse prognosis was found. TMEM64 enhanced cell proliferation and tumorigenicity while inhibiting glioma cell apoptosis in vitro and in vivo, according to loss- and gain-of-function studies. Mechanistically, it was discovered that TMEM64 increased the malignant phenotype of gliomas by accelerating the translocation of β-catenin from the cytoplasm to the nucleus, thereby activating the Wnt/β-catenin signaling pathway. Stimulation with the Wnt/β-catenin signaling pathway activator CHIR-99021 successfully reversed the malignant phenotype of glioma; however, these effects were inhibited upon TMEM64 silencing. Stimulation with the Wnt/β-catenin signaling pathway inhibitor XAV-939 successfully rescued the malignant phenotype of glioma, which was promoted upon TMEM64 overexpression. Our results provide that TMEM64 as a novel prognostic biomarker and a potential treatment target for glioma.

TMED2 promotes glioma tumorigenesis by being involved in EGFR recycling transport

Aberrant epidermal growth factor receptor (EGFR) signaling is the core signaling commonly activated in glioma. The transmembrane emp24 protein transport domain protein 2 (TMED2) interacts with cargo proteins involved in protein sorting and transport between endoplasmic reticulum (ER) and Golgi apparatus. In this study, we found the correlation between TMED2 with glioma progression and EGFR signaling through database analysis. Moreover, we demonstrated that TMED2 is essential for glioma cell proliferation, migration, and invasion at the cellular levels, as well as tumor formation in mouse models, underscoring its significance in the pathobiology of gliomas. Mechanistically, TMED2 was found to enhance EGFR-AKT signaling by facilitating EGFR recycling, thereby providing the initial evidence of TMED2's involvement in the membrane protein recycling process. In summary, our findings shed light on the roles and underlying mechanisms of TMED2 in the regulation of glioma tumorigenesis and EGFR signaling, suggesting that targeting TMED2 could emerge as a promising therapeutic strategy for gliomas and other tumors associated with aberrant EGFR signaling.

Hsa_circ_0021205 enhances lipolysis via regulating miR-195-5p/HSL axis and drives malignant progression of glioblastoma

Abnormal lipid metabolism is an essential hallmark of glioblastoma. Hormone sensitive lipase (HSL), an important rate-limiting enzyme contributed to lipolysis, which was involved in aberrant lipolysis of glioblastoma, however, its definite roles and the relevant regulatory pathway have not been fully elucidated. Our investigations disclosed high expression of HSL in glioblastoma. Knock-down of HSL restrained proliferation, migration, and invasion of glioblastoma cells while adding to FAs could significantly rescue the inhibitory effect of si-HSL on tumor cells. Overexpression of HSL further promoted tumor cell proliferation and invasion. Bioinformatics analysis and dual-luciferase reporter assay were performed to predict and verify the regulatory role of ncRNAs on HSL. Mechanistically, hsa_circ_0021205 regulated HSL expression by sponging miR-195-5p, which further promoted lipolysis and drove the malignant progression of glioblastoma. Besides, hsa_circ_0021205/miR-195-5p/HSL axis activated the epithelial-mesenchymal transition (EMT) signaling pathway. These findings suggested that hsa_circ_0021205 promoted tumorigenesis of glioblastoma through regulation of HSL, and targeting hsa_circ_0021205/miR-195-5p/HSL axis can serve as a promising new strategy against glioblastoma.

Identification of EMT-associated prognostic features among grade II/III gliomas

Grade II/III gliomas have a highly heterogeneous clinical course. Identifying prognostic biomarkers in grade II/III gliomas is essential to guide clinical management. We explored epithelial-mesenchymal transition (EMT)-related genes to uncover prognostic features in grade II/III gliomas. Consensus cluster analysis of 200 EMT-related genes classified 512 grade II/III glioma samples into two molecular subtypes, C1 and C2. The C1 subtype had significantly worse overall survival compared to the C2 subtype. Pathway analysis revealed C1 tumors were highly associated with tumor progression pathways and demonstrated higher immune cell infiltration scores. Differential expression analysis identified four genes (ACTN1, AQP1, LAMC3, NRM) that discriminated the two subtypes. Validation in external datasets confirmed that high expression of this four-gene signature predicted poor prognosis in grade II/III gliomas. Cellular experiments showed ACTN1, AQP1 and NRM promoted glioma cell proliferation, migration and invasion. We examined correlations of the signature genes with T cell exhaustion markers and found ACTN1 expression had the strongest association. Immunohistochemistry analysis further demonstrated that ACTN1 protein expression in grade II/III gliomas was negatively correlated with patient overall survival. In summary, our study identified a concise four-gene signature that robustly predicts grade II/III gliomas prognosis across multiple datasets. The signature provides clinical relevance in distinguishing more aggressive grade II/III glioma tumors. Targeting the ACTN1, AQP1 and NRM genes may offer new therapeutic opportunities to improve grade II/III gliomas patient outcomes.

Image-Based Subtype Classification for Glioblastoma Using Deep Learning: Prognostic Significance and Biologic Relevance

PURPOSE

To apply deep learning algorithms to histopathology images, construct image-based subtypes independent of known clinical and molecular classifications for glioblastoma, and produce novel insights into molecular and immune characteristics of the glioblastoma tumor microenvironment.

MATERIALS AND METHODS

Using whole-slide hematoxylin and eosin images from 214 patients with glioblastoma in The Cancer Genome Atlas (TCGA), a fine-tuned convolutional neural network model extracted deep learning features. Biclustering was used to identify subtypes and image feature modules. Prognostic value of image subtypes was assessed via Cox regression on survival outcomes and validated with 189 samples from the Clinical Proteomic Tumor Analysis Consortium (CPTAC) data set. Morphological, molecular, and immune characteristics of glioblastoma image subtypes were analyzed.

RESULTS

Four distinct subtypes and modules (imClust1-4) were identified for the TCGA patients with glioblastoma on the basis of the image feature data. The glioblastoma image subtypes were significantly associated with overall survival (OS; P = .028) and progression-free survival (P = .003). Apparent association was also observed for disease-specific survival (P = .096). imClust2 had the best prognosis for all three survival end points (eg, after 25 months, imClust2 had >7% surviving patients than the other subtypes). Examination of OS in the external validation using the unseen CPTAC data set showed consistent patterns. Multivariable Cox analyses confirmed that the image subtypes carry unique prognostic information independent of known clinical and molecular predictors. Molecular and immune profiling revealed distinct immune compositions of the tumor microenvironment in different image subtypes and may provide biologic explanations for the patterns in patients' outcomes.

CONCLUSION

Our image-based subtype classification on the basis of deep learning models is a novel tool to refine risk stratification in cancers. The image subtypes detected for glioblastoma represent a promising prognostic biomarker with distinct molecular and immune characteristics and may facilitate developing novel, individualized immunotherapies for glioblastoma.

Glioblastoma Multiforme miRNA based Comprehensive Study to Validate Phytochemicals for Effective Treatment against Deadly Tumour through In Silico Evaluation

BACKGROUND

Glioblastoma Multiforme (GBM) is a prevalent and deadly type of primary astrocytoma, constituting over 60% of adult brain tumors, and has a poor prognosis, with a high relapse rate within 7 months of diagnosis. Despite surgical, radiotherapy, and chemotherapy treatments, GBM remains challenging due to resistance. MicroRNA (miRNAs) control gene expression at transcriptional and post-transcriptional levels by targeting their messenger RNA (mRNA), and also contribute to the development of various neoplasms, including GBM.

METHODS

The present study focuses on exploring the miRNAs-based pathogenesis of GBM and evaluating most potential plant-based therapeutic agents with in silico analysis. Gene chips were retrieved from the Gene Expression Omnibus (GEO) database, followed by the Robust- Rank- Aggereg algorithm to determine the Differentially Expressed miRNAs (DEMs). The predicted targets were intersected with the GBM-associated genes, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of the overlapping genes was performed. At the same time, five phytochemicals were selected for the Connectivity map (CMap), and the most efficient ones were those that had undergone molecular docking analysis to obtain the potential therapeutic agents.

RESULTS

The hsa-miR-10b, hsa-miR-21, and hsa-miR-15b were obtained, and eight genes were found to be associated with glioma pathways; VSIG4, PROCR, PLAT, and ITGB2 were upregulated while, CAMK2B, PDE1A, GABRA1, and KCNJ6 were downregulated. The drugs Resveratrol and Quercetin were identified as the most prominent drugs.

CONCLUSION

These miRNAs-based drugs can be used as a curative agent for the treatment of GBM. However, in vivo, experimental data, and clinical trials are necessary to provide an alternative to conventional GBM cancer chemotherapy.

RPL22L1, a novel candidate oncogene promotes temozolomide resistance by activating STAT3 in glioblastoma

Aggressiveness and drug resistance are major challenges in the clinical treatment of glioblastoma (GBM). Our previously research reported a novel candidate oncogene ribosomal protein L22 like 1 (RPL22L1). The aim of this study was to elucidate the potential role and mechanism of RPL22L1 in progression and temozolomide (TMZ) resistance of GBM. Online database, tissue microarrays and clinical tissue specimens were used to evaluate the expression and clinical implication of RPL22L1 in GBM. We performed cell function assays, orthotopic and subcutaneous xenograft tumor models to evaluate the effects and molecular mechanisms of RPL22L1 on GBM. RPL22L1 expression was significantly upregulated in GBM and associated with poorer prognosis. RPL22L1 overexpression enhanced GBM cell proliferation, migration, invasion, TMZ resistance and tumorigenicity, which could be reduced by RPL22L1 knockdown. Further, we found RPL22L1 promoted mesenchymal phenotype of GBM and the impact of these effects was closely related to EGFR/STAT3 pathway. Importantly, we observed that STAT3 specific inhibitor (Stattic) significantly inhibited the malignant functions of RPL22L1, especially on TMZ resistance. RPL22L1 overexpressed increased combination drug sensitive of Stattic and TMZ both in vitro and in vivo. Moreover, Stattic effectively restored the sensitive of RPL22L1 induced TMZ resistance in vitro and in vivo. Our study identified a novel candidate oncogene RPL22L1 which promoted the GBM malignancy through STAT3 pathway. And we highlighted that Stattic combined with TMZ therapy might be an effective treatment strategy in RPL22L1 high-expressed GBM patients.

Improving the efficacy of anti-EGFR drugs in GBM: Where we are going?

The therapies targeting mutations of driver genes in cancer have advanced into clinical trials for a variety of tumors. In glioblastoma (GBM), epidermal growth factor receptor (EGFR) is the most commonly mutated oncogene, and targeting EGFR has been widely investigated as a promising direction. However, the results of EGFR pathway inhibitors have not been satisfactory. Limited blood-brain barrier (BBB) permeability, drug resistance, and pathway compensation mechanisms contribute to the failure of anti-EGFR therapies. This review summarizes recent research advances in EGFR-targeted therapy for GBM and provides insight into the reasons for the unsatisfactory results of EGFR-targeted therapy. By combining the results of preclinical studies with those of clinical trials, we discuss that improved drug penetration across the BBB, the use of multi-target combinations, and the development of peptidomimetic drugs under the premise of precision medicine may be promising strategies to overcome drug resistance in GBM.

Redox Homeostasis and Beyond: The Role of Wild-Type Isocitrate Dehydrogenases for the Pathogenesis of Glioblastoma

Significance: Glioblastoma is an aggressive and devastating brain tumor characterized by a dismal prognosis and resistance to therapeutic intervention. To support catabolic processes critical for unabated cellular growth and defend against harmful reactive oxygen species, glioblastoma tumors upregulate the expression of wild-type isocitrate dehydrogenases (IDHs). IDH enzymes catalyze the oxidative decarboxylation of isocitrate to α-ketoglutarate (α-KG), NAD(P)H, and CO2. On molecular levels, IDHs epigenetically control gene expression through effects on α-KG-dependent dioxygenases, maintain redox balance, and promote anaplerosis by providing cells with NADPH and precursor substrates for macromolecular synthesis. Recent Advances: While gain-of-function mutations in IDH1 and IDH2 represent one of the most comprehensively studied mechanisms of IDH pathogenic effects, recent studies identified wild-type IDHs as critical regulators of normal organ physiology and, when transcriptionally induced or down regulated, as contributing to glioblastoma progression. Critical Issues: Here, we will discuss molecular mechanisms of how wild-type IDHs control glioma pathogenesis, including the regulation of oxidative stress and de novo lipid biosynthesis, and provide an overview of current and future research directives that aim to fully characterize wild-type IDH-driven metabolic reprogramming and its contribution to the pathogenesis of glioblastoma. Future Directions: Future studies are required to further dissect mechanisms of metabolic and epigenomic reprogramming in tumors and the tumor microenvironment, and to develop pharmacological approaches to inhibit wild-type IDH function. Antioxid. Redox Signal. 39, 923-941.

JAK3 Inhibition Regulates Stemness and Thereby Controls Glioblastoma Pathogenesis

Glioblastoma multiforme (GBM) is the most deadly brain tumor, effective treatment options for which still remain elusive. The current treatment procedure of maximal resection followed by chemotherapy has proved to be grossly insufficient to prevent disease progression and death. Despite best efforts, the maximum survival post-diagnosis is a mere 1.5 years. Therefore, there is a huge unmet clinical need to find effective therapeutic procedures to prevent the pathogenesis and relapse of GBM. Small-molecule inhibitors of signaling pathways are an attractive option to prevent various types of tumors. However, no effective small-molecule inhibitors have been successful against GBM in clinical trials. Various signaling pathways are altered and an array of signaling molecules, transcription factors (TFs), and epigenetic modifying factors have been implicated in the pathogenesis of GBM. JAK-STAT pathway alteration is an important contributor to GBM pathogenesis and relapse. Many small-molecule inhibitors of JAKs, or STAT TFs, especially JAK2 and STAT3, have been assessed for their anti-tumor activity in GBM. However, no definitive success so far has been achieved. Herein, by using two small-molecule inhibitors of JAK3, we show that they are quite effective in inhibiting GBM cell proliferation and neurosphere formation, downregulating their stemness character, and inducing differentiation into neuronal origin cells. The effect of a single treatment with the drugs, both in a serum-containing differentiation medium and in a proliferation medium containing EGF and FGF, was really strong in limiting GBM cell growth, suggesting a potential therapeutic application for these JAK inhibitors in GBM therapy.

Glioblastoma Vascular Plasticity Limits Effector T-cell Infiltration and Is Blocked by cAMP Activation

Glioblastoma (GBM) is the deadliest form of brain cancer. It is a highly angiogenic and immunosuppressive malignancy. Although immune checkpoint blockade therapies have revolutionized treatment for many types of cancer, their therapeutic efficacy in GBM has been far less than expected or even ineffective. In this study, we found that the genomic signature of glioma-derived endothelial cells (GdEC) correlates with an immunosuppressive state and poor prognosis of patients with glioma. We established an in vitro model of GdEC differentiation for drug screening and used this to determine that cyclic adenosine monophosphate (cAMP) activators could effectively block GdEC formation by inducing oxidative stress. Furthermore, cAMP activators impaired GdEC differentiation in vivo, normalized the tumor vessels, and altered the tumor immune profile, especially increasing the influx and function of CD8+ effector T cells. Dual blockade of GdECs and PD-1 induced tumor regression and established antitumor immune memory. Thus, our study reveals that endothelial transdifferentiation of GBM shapes an endothelial immune cell barrier and supports the clinical development of combining GdEC blockade and immunotherapy for GBM. See related Spotlight by Lee et al., p. 1300.

Strategies increasing the effectiveness of temozolomide at various levels of anti-GBL therapy

Glioblastoma (GBL) is the most common (60-70% of primary brain tumours) and the most malignant of the glial tumours. Although current therapies remain palliative, they have been proven to prolong overall survival. Within an optimal treatment regimen (incl. surgical resection, radiation therapy, and chemotherapy) temozolomide as the current anti-GBL first-line chemotherapeutic has increased the median overall survival to 14-15 months, and the percentage of patients alive at two years has been reported to rise from 10.4% to 26.5%. Though, the effectiveness of temozolomide chemotherapy is limited by the serious systemic, dose-related side effects. Therefore, the ponderation regarding novel treatment methods along with innovative formulations is crucial to emerging the therapeutic potential of the widely used drug simultaneously reducing the drawbacks of its use. Herein the complex temozolomide application restrictions present at different levels of therapy as well as, the currently proposed strategies aimed at reducing those limitations are demonstrated. Approaches increasing the efficacy of anti-GBL treatment are addressed. Our paper is focused on the most recent developments in the field of nano/biomaterials-based systems for temozolomide delivery and their functionalization towards more effective blood-brain-barrier crossing and/or tumour targeting. Appropriate designing accounting for the physical and chemical features of formulations along with distinct routes of administration is also discussed. In addition, considering the multiple resistance mechanisms, the molecular heterogeneity and the evolution of tumour the purposely selected delivery methods, the combined therapeutic approaches and specifically focused on GBL cells therapies are reviewed.

Dissection of transcriptomic and epigenetic heterogeneity of grade 4 gliomas: implications for prognosis

BACKGROUND

Grade 4 glioma is the most aggressive and currently incurable brain tumor with a median survival of one year in adult patients. Elucidating novel transcriptomic and epigenetic contributors to the molecular heterogeneity underlying its aggressiveness may lead to improved clinical outcomes.

METHODS

To identify grade 4 glioma -associated 5-hydroxymethylcytosine (5hmC) and transcriptomic features as well as their cross-talks, genome-wide 5hmC and transcriptomic profiles of tissue samples from 61 patients with grade 4 gliomas and 9 normal controls were obtained for differential and co-regulation/co-modification analyses. Prognostic models on overall survival based on transcriptomic features and the 5hmC modifications summarized over genic regions (promoters, gene bodies) and brain-derived histone marks were developed using machine learning algorithms.

RESULTS

Despite global reduction, the majority of differential 5hmC features showed higher modification levels in grade 4 gliomas as compared to normal controls. In addition, the bi-directional correlations between 5hmC modifications over promoter regions or gene bodies and gene expression were greatly disturbed in grade 4 gliomas regardless of IDH1 mutation status. Phenotype-associated co-regulated 5hmC-5hmC modules and 5hmC-mRNA modules not only are enriched with different molecular pathways that are indicative of the pathogenesis of grade 4 gliomas, but also are of prognostic significance comparable to IDH1 mutation status. Lastly, the best-performing 5hmC model can predict patient survival at a much higher accuracy (c-index = 74%) when compared to conventional prognostic factor IDH1 (c-index = 57%), capturing the molecular characteristics of tumors that are independent of IDH1 mutation status and gene expression-based molecular subtypes.

CONCLUSIONS

The 5hmC-based prognostic model could offer a robust tool to predict survival in patients with grade 4 gliomas, potentially outperforming existing prognostic factors such as IDH1 mutations. The crosstalk between 5hmC and gene expression revealed another layer of complexity underlying the molecular heterogeneity in grade 4 gliomas, offering opportunities for identifying novel therapeutic targets.

TRIB1 confers therapeutic resistance in GBM cells by activating the ERK and Akt pathways

GBM (Glioblastoma) is the most lethal CNS (Central nervous system) tumor in adults, which inevitably develops resistance to standard treatments leading to recurrence and mortality. TRIB1 is a serine/threonine pseudokinase which functions as a scaffold platform that initiates degradation of its substrates like C/EBPα through the ubiquitin proteasome system and also activates MEK and Akt signaling. We found that increased TRIB1 gene expression associated with worse overall survival of GBM patients across multiple cohorts. Importantly, overexpression of TRIB1 decreased RT/TMZ (radiation therapy/temozolomide)-induced apoptosis in patient derived GBM cell lines in vitro. TRIB1 directly bound to MEK and Akt and increased ERK and Akt phosphorylation/activation. We also found that TRIB1 protein expression was maximal during G2/M transition of cell cycle in GBM cells. Furthermore, TRIB1 bound directly to HDAC1 and p53. Importantly, mice bearing TRIB1 overexpressing tumors had worse overall survival. Collectively, these data suggest that TRIB1 induces resistance of GBM cells to RT/TMZ treatments by activating the cell proliferation and survival pathways thus providing an opportunity for developing new targeted therapeutics.

Identification of a Novel Eight-Gene Risk Model for Predicting Survival in Glioblastoma: A Comprehensive Bioinformatic Analysis

Glioblastoma (GBM) is one of the most progressive and prevalent cancers of the central nervous system. Identifying genetic markers is therefore crucial to predict prognosis and enhance treatment effectiveness in GBM. To this end, we obtained gene expression data of GBM from TCGA and GEO datasets and identified differentially expressed genes (DEGs), which were overlapped and used for survival analysis with univariate Cox regression. Next, the genes' biological significance and potential as immunotherapy candidates were examined using functional enrichment and immune infiltration analysis. Eight prognostic-related DEGs in GBM were identified, namely CRNDE, NRXN3, POPDC3, PTPRN, PTPRN2, SLC46A2, TIMP1, and TNFSF9. The derived risk model showed robustness in identifying patient subgroups with significantly poorer overall survival, as well as those with distinct GBM molecular subtypes and MGMT status. Furthermore, several correlations between the expression of the prognostic genes and immune infiltration cells were discovered. Overall, we propose a survival-derived risk score that can provide prognostic significance and guide therapeutic strategies for patients with GBM.

SREBP-1 upregulates lipophagy to maintain cholesterol homeostasis in brain tumor cells

Cholesterol is a structural component of cell membranes. How rapidly growing tumor cells maintain membrane cholesterol homeostasis is poorly understood. Here, we found that glioblastoma (GBM), the most lethal brain tumor, maintains normal levels of membrane cholesterol but with an abundant presence of cholesteryl esters (CEs) in its lipid droplets (LDs). Mechanistically, SREBP-1 (sterol regulatory element-binding protein 1), a master transcription factor that is activated upon cholesterol depletion, upregulates critical autophagic genes, including ATG9B, ATG4A, and LC3B, as well as lysosome cholesterol transporter NPC2. This upregulation promotes LD lipophagy, resulting in the hydrolysis of CEs and the liberation of cholesterol from the lysosomes, thus maintaining plasma membrane cholesterol homeostasis. When this pathway is blocked, GBM cells become quite sensitive to cholesterol deficiency with poor growth in vitro. Our study unravels an SREBP-1-autophagy-LD-CE hydrolysis pathway that plays an important role in maintaining membrane cholesterol homeostasis while providing a potential therapeutic avenue for GBM.