Glioblastoma and Other Primary Brain Malignancies in Adults: A Review

Prospects of marine-derived compounds as potential therapeutic agents for glioma

CONTEXT

Glioma, the most common primary malignant brain tumour, is a grave health concern associated with high morbidity and mortality. Current treatments, while effective to some extent, are often hindered by factors such as the blood-brain barrier and tumour microenvironment. This underscores the pressing need for exploring new pharmacologically active anti-glioma compounds.

METHODS

This review synthesizes information from major databases, including Chemical Abstracts, Medicinal and Aromatic Plants Abstracts, ScienceDirect, SciFinder, Google Scholar, Scopus, PubMed, Springer Link and relevant books. Publications were selected without date restrictions, using terms such as 'Hymenocrater spp.,' 'phytochemical,' 'pharmacological,' 'extract,' 'essential oil' and 'traditional uses.' General web searches using Google and Yahoo were also performed. Articles related to agriculture, ecology, synthetic work or published in languages other than English or Chinese were excluded.

RESULTS

The marine environment has been identified as a rich source of diverse natural products with potent antitumour properties.

CONCLUSIONS

This paper not only provides a comprehensive review of marine-derived compounds but also unveils their potential in treating glioblastoma multiforme (GBM) based on functional classifications. It encapsulates the latest research progress on the regulatory biological functions and mechanisms of these marine substances in GBM, offering invaluable insights for the development of new glioma treatments.

The prognostic effect of mechanical, ultrastructural, and ECM signatures in glioblastoma core and rim

Glioblastoma (GBM) is a highly invasive, aggressive brain cancer that carries a median survival of 15 months and is resistant to standard therapeutics. Recent studies have demonstrated that intratumoral heterogeneity plays a critical role in promoting resistance by mediating tumor adaptation through microenvironmental cues. GBM can be separated into two distinct regions-a core and a rim, which are thought to drive specific aspects of tumor evolution. These differences in tumor progression are regulated by the diverse biomolecular and biophysical signals in these regions, but the acellular biophysical characteristics remain poorly described. This study investigates the mechanical and ultrastructural characteristics of the tumor extracellular matrix (ECM) in patient-matched GBM core and rim tissues. Seven patient-matched tumor core and rim samples and one non-neoplastic control were analyzed using atomic force microscopy, scanning electron microscopy, and immunofluorescence imaging to quantify mechanical, ultrastructural, and ECM composition changes. The results reveal significant differences in biophysical parameters between GBM core, rim, and non-neoplastic tissues. The GBM core is stiffer, denser, and is rich in ECM proteins hyaluronic acid and tenascin-C when compared to tumor rim and non-neoplastic tissues. These alterations are intimately related and have prognostic effect with stiff, dense tissue correlating with longer progression-free survival. These findings reveal new insights into the spatial heterogeneity of biophysical parameters in the GBM tumor microenvironment and identify a set of characteristics that may correlate with patient prognosis. In the long term, these characteristics may aid in the development of strategies to combat therapeutic resistance.

Impact of frailty on survival glioblastoma, IDH-wildtype patients

PURPOSE

Frailty increases the risk of mortality among patients. We studied the prognostic significance of frailty using the modified 5-item frailty index (5-mFI) in patients harboring a newly diagnosed supratentorial glioblastoma, IDH-wildtype.

METHODS

We retrospectively reviewed records of patients surgical treated at a single neurosurgical institution at the standard radiochemotherapy era (January 2006 - December 2021). Inclusion criteria were: age ≥ 18, newly diagnosed glioblastoma, IDH-wildtype, supratentorial location, available data to assess the 5-mFI index.

RESULTS

A total of 694 adult patients were included. The median overall survival was longer in the non-frail subgroup (5-mFI < 2, n = 538 patients; 14.3 months, 95%CI 12.5-16.0) than in the frail subgroup (5-mFI ≥ 2, n = 156 patients; 4.7 months, 95%CI 4.0-6.5 months; p < 0.001). 5-mFI ≥ 2 (adjusted Hazard Ratio (aHR) 1.31; 95%CI 1.07-1.61; p = 0.009) was an independent predictor of a shorter overall survival while age ≤ 60 years (aHR 0.78; 95%CI 0.66-0.93; p = 0.007), KPS score ≥ 70 (aHR 0.71; 95%CI 0.58-0.87; p = 0.001), unilateral location (aHR 0.67; 95%CI 0.52-0.87; p = 0.002), total removal (aHR 0.54; 95%CI 0.44-0.64; p < 0.0001), and standard radiochemotherapy protocol (aHR 0.32; 95%CI 0.26-0.38; p < 0.0001) were independent predictors of a longer overall survival. Frailty remained an independent predictor of overall survival within the subgroup of patients undergoing a first-line oncological treatment after surgery (n = 549) and within the subgroup of patients who benefited from a total removal plus adjuvant standard radiochemotherapy (n = 209).

CONCLUSION

In newly diagnosed supratentorial glioblastoma, IDH-wildtype patients treated at the standard combined radiochemotherapy era, frailty, defined using a 5-mFI score ≥ 2 was an independent predictor of overall survival.

TRIM6 promotes glioma malignant progression by enhancing FOXO3A ubiquitination and degradation

PURPOSE

TRIM6, an E3 ubiquitin ligase with tripartite motif, directly targets protein substrates for degradation through ubiquitination. Studies have shown that TRIM6 plays a significant role in tumor development in various human malignancies. Thus, the aim of this study was to investigate the importance of TRIM6 and its associated mechanism in promoting the progression of glioma.

METHODS

The expression of TRIM6 and its prognostic value in glioma patients were collected from the TCGA and CGGA databases. The effects of TRIM6 on glioma were investigated in vitro by CCK8, colony formation, wound healing, and transwell assays. Co-IP and western blot analysis were used to detect the interaction between TRIM6 and FOXO3A. The effects of TRIM6 were verified in vivo in subcutaneously xenograft models, and tumor size, and immunohistochemical changes were observed.

RESULTS

Our analysis of TRIM6 expression in glioma tissues revealed a high level of expression, and the heightened expression of TRIM6 showed a positive correlation with the unfavorable prognosis among glioma/GBM patients. Through loss-of-function and gain-of-function experiments, we observed a profound impact on the proliferation, invasion, and migration abilities of glioma cells both in vitro and in vivo upon deletion of TRIM6. Conversely, the overexpression of TRIM6 intensified the malignant characteristics of glioma. Additionally, our findings revealed a significant interaction between TRIM6 and FOXO3A, wherein TRIM6 contributed to the destabilization of FOXO3A protein by promoting its ubiquitination and subsequent degradation. Experiments conducted in the rescue study affirmed that the promotion of glioma cell proliferation, invasion, and migration is facilitated by TRIM6 through the suppression of FOXO3A protein levels.

CONCLUSIONS

These observations imply that the TRIM6-FOXO3A axis could potentially serve as an innovative focus for intervening in glioma.

4,5-Dimethoxycanthin-6-one Inhibits Glioblastoma Stem Cell and Tumor Growth by Inhibiting TSPAN1 Interaction with TM4SF1

Glioblastoma stem cells (GSCs) have been implicated in the self-renewal and treatment resistance of glioblastoma (GBM). Our previous study found that 4,5-dimethoxycanthin-6-one has the potential to inhibit GBM cell proliferation. This current study aims to elucidate the molecular mechanism underlying the effects of 4,5-dimethoxycanthin-6-one in GBM development. The effect of 4,5-dimethoxycanthin-6-one on GSC formation and differentiation was explored in human GBM cell lines U251 and U87. Subsequently, 4,5-dimethoxycanthin-6-one binding to tetraspanin 1 (TSPAN1) / transmembrane 4 L six family member 1 (TM4SF1) was analyzed by molecular simulation docking. Co-immunoprecipitation (Co-IP) and immunofluorescence (IF) were used to assess the interactions between TSPAN1 and TM4SF1 in GSCs. Cell proliferation was detected by cell counting kit-8 (CCK-8) and colony formation assay. To evaluate cell migration, invasion and apoptosis, we employed wound healing assay, transwell and flow cytometry, respectively. Furthermore, subcutaneous xenograft tumor models in nude mice were constructed to evaluate the impact of 4,5-dimethoxycanthin-6-one on GSCs in vivo by examining tumor growth and histological characteristics. 4,5-Dimethoxycanthin-6-one inhibited GSC formation and promoted stem cell differentiation in a concentration-dependent manner. Molecular docking models of 4,5-dimethoxycanthin-6-one with TM4SF1 and TSPAN1 were constructed. Then, the interaction between TSPAN1 and TM4SF1 in GSC was clarified. Moreover, 4,5-dimethoxycanthin-6-one significantly inhibited the expressions of TM4SF1 and TSPAN1 in vitro and in vivo. Overexpression of TSPAN1 partially reversed the inhibitory effects of 4,5-dimethoxycanthin-6-one on GSC formation, proliferation, migration and invasion. 4,5-Dimethoxycanthin-6-one inhibited GBM progression by inhibiting TSPAN1/TM4SF1 axis. 4,5-Dimethoxycanthin-6-one might be a novel and effective drug for the treatment of GBM.

Breaking Down Glioma-Microenvironment Crosstalk

High-grade gliomas (HGGs) are the commonest primary brain cancers. They are characterized by a pattern of aggressive growth and diffuse infiltration of the host brain that severely limits the efficacy of conventional treatments and patient outcomes, which remain generally poor. Recent work has described a suite of mechanisms via which HGGs interact, predominantly bidirectionally, with various cell types in the host brain including neurons, glial cells, immune cells, and vascular elements to drive tumor growth and invasion. These insights have the potential to inspire novel approaches to HGG therapy that are critically needed. This review explores HGG-host brain interactions and considers whether and how they might be exploited for therapeutic gain.

Quantification of the Engraftment Status of Mesenchymal Stem Cells in Glioma Using Dual-Modality Magnetic Resonance Imaging and Bioluminescence Imaging

RATIONALE AND OBJECTIVES

The tumor-tropic properties of mesenchymal stem cells (MSCs) enable them to serve as appealing cellular vehicles for delivering therapeutic agents to treat malignant glioma. However, the exact engraftment status of MSCs in glioma via different administration routes remains unclear due to the lack of quantitative analysis. This study aimed to quantify the engraftment of MSCs in glioma after administration via different routes using non-invasive dual-modality magnetic resonance imaging (MRI) and bioluminescence imaging (BLI).

MATERIALS AND METHODS

MSCs were transduced with a lentivirus overexpressing ferritin heavy chain (FTH) and firefly luciferase (FLUC) reporter genes to yield FTH- and FLUC-overexpressed MSCs (FTH-FLUC-MSCs). Wistar rats bearing intracranial C6 glioma received peritumoral, intratumoral, intra-arterial, and intravenous injection of FTH-FLUC-MSCs, respectively. MRI and BLI were performed to monitor FTH-FLUC-MSCs in vivo.

RESULTS

FTH-FLUC-MSCs administered via peritumoral, intratumoral and intra-arterial routes migrated specially toward the intracranial glioma in vivo, as detected by MRI and BLI. As quantified by the BLI signal intensity, the percentages of FTH-FLUC-MSCs in the glioma were significantly higher with peritumoral injection (61%) and intratumoral injection (71%) compared to intra-arterial injection (30%) and intravenous injection (0%). Peritumorally injected FTH-FLUC-MSCs showed a gradual decline, with approximately 6% of FTH-FLUC-MSCs still retained within the tumor up to 11 days after injection. Meanwhile, the number of FTH-FLUC-MSCs injected via other routes dropped quickly, and none were detectable by day 11 post-injection.

CONCLUSION

Peritumoral delivery of FTH-FLUC-MSCs offers robust engraftment and could be used as the optimal delivery route for treating malignant glioma.

Glioma grade and post-neurosurgical meningitis risk

BACKGROUND

Post-neurosurgical meningitis (PNM) constitutes a grave complication associated with substantial morbidity and mortality. This study aimed to determine the risk factors predisposing patients to PNM following surgery for low- and high-grade gliomas.

METHODS

We conducted a retrospective analysis encompassing all patients who underwent glioma surgery involving craniotomy at Turku University Hospital, Turku, Finland, between 2011 and 2018. Inclusion criteria for PNM were defined as follows: (1) Positive cerebrospinal fluid (CSF) culture, (2) CSF leukocyte count ≥ 250 × 106/L with granulocyte percentage ≥ 50%, or (3) CSF lactate concentration ≥ 4 mmol/L, detected after glioma surgery. Glioma grades 3-4 were classified as high-grade (n = 261), while grades 1-2 were designated as low-grade (n = 84).

RESULTS

Among the 345 patients included in this study, PNM developed in 7% (n = 25) of cases. The median time interval between glioma surgery and diagnosis of PNM was 12 days. Positive CSF cultures were observed in 7 (28%) PNM cases, with identified pathogens encompassing Staphylococcus epidermidis (3), Staphylococcus aureus (2), Enterobacter cloacae (1), and Pseudomonas aeruginosa (1). The PNM group exhibited a higher incidence of reoperations (52% vs. 18%, p < 0.001) and revision surgery (40% vs. 6%, p < 0.001) in comparison to patients without PNM. Multivariable analysis revealed that reoperation (OR 2.63, 95% CI 1.04-6.67) and revision surgery (OR 7.08, 95% CI 2.55-19.70) were significantly associated with PNM, while glioma grade (high-grade vs. low-grade glioma, OR 0.81, 95% CI 0.30-2.22) showed no significant association.

CONCLUSIONS

The PNM rate following glioma surgery was 7%. Patients requiring reoperation and revision surgery were at elevated risk for PNM. Glioma grade did not exhibit a direct link with PNM; however, the presence of low-grade gliomas may indirectly heighten the PNM risk through an increased likelihood of future reoperations. These findings underscore the importance of meticulous post-operative care and infection prevention measures in glioma surgeries.

Human translesion DNA polymerases ι and κ mediate tolerance to temozolomide in MGMT-deficient glioblastoma cells

Glioblastoma (GBM) is a highly aggressive brain tumor associated with poor patient survival. The current standard treatment involves invasive surgery, radiotherapy, and chemotherapy employing temozolomide (TMZ). Resistance to TMZ is, however, a major challenge. Previous work from our group has identified candidate genes linked to TMZ resistance, including genes encoding translesion synthesis (TLS) DNA polymerases iota (Polɩ) and kappa (Polκ). These specialized enzymes are known for bypassing lesions and tolerating DNA damage. Here, we investigated the roles of Polɩ and Polκ in TMZ resistance, employing MGMT-deficient U251-MG glioblastoma cells, with knockout of either POLI or POLK genes encoding Polɩ and Polκ, respectively, and assess their viability and genotoxic stress responses upon subsequent TMZ treatment. Cells lacking either of these polymerases exhibited a significant decrease in viability following TMZ treatment compared to parental counterparts. The restoration of the missing polymerase led to a recovery of cell viability. Furthermore, knockout cells displayed increased cell cycle arrest, mainly in late S-phase, and lower levels of genotoxic stress after TMZ treatment, as assessed by a reduction of γH2AX foci and flow cytometry data. This implies that TMZ treatment does not trigger a significant H2AX phosphorylation response in the absence of these proteins. Interestingly, combining TMZ with Mirin (double-strand break repair pathway inhibitor) further reduced the cell viability and increased DNA damage and γH2AX positive cells in TLS KO cells, but not in parental cells. These findings underscore the crucial roles of Polɩ and Polκ in conferring TMZ resistance and the potential backup role of homologous recombination in the absence of these TLS polymerases. Targeting these TLS enzymes, along with double-strand break DNA repair inhibition, could, therefore, provide a promising strategy to enhance TMZ's effectiveness in treating GBM.

Causal relationship between type 2 diabetes and glioblastoma: bidirectional Mendelian randomization analysis

As the prevalence of Type 2 Diabetes Mellitus (T2DM) and Glioblastoma (GBM) rises globally, the relationship between T2DM and GBM remains controversial. This study aims to investigate whether genetically predicted T2DM is causally associated with GBM. We performed bidirectional Mendelian randomization (MR) analysis using data from genome-wide studies on T2DM (N = 62,892) and GBM (N = 218,792) in European populations. The results of the inverse-variance weighted (IVW) approach served as the primary outcomes. We applied Cochran's Q test and MR-Egger regression for heterogeneity assessment. Leave-one-out analysis was used to evaluate whether any single SNP significantly influenced the observed effect. Our findings reveal a significant causal association between T2DM and an increased risk of GBM (OR [95% CI] 1.70 [1.09, 2.65], P = 0.019). Conversely, the reverse association between T2DM and GBM was insignificant (OR [95% CI] 1.00 [0.99, 1.01], P = 0.408) (P > 0.40). Furthermore, the results from Cochran's Q-test and funnel plots in the MR-Egger method indicated no evidence of pleiotropy between the SNPs and GBM. Additionally, we mapped causal SNPs to genes and identified 10 genes, including MACF1, C1orf185, PTGFRN, NOTCH2, ABCB10, GCKR, THADA, RBMS1, SPHKAP, and PPARG, located on chromosomes 1, 2, and 3. These genes are involved in key biological processes such as the BMP signaling pathway and various metabolic pathways relevant to both conditions. This study provides robust evidence of a significant causal relationship between T2DM and an increased risk of GBM. The identified SNP-mapped genes highlight potential biological mechanisms underlying this association.

Radiogenomics as an Integrated Approach to Glioblastoma Precision Medicine

PURPOSE OF REVIEW

Isocitrate dehydrogenase wild-type glioblastoma is the most aggressive primary brain tumour in adults. Its infiltrative nature and heterogeneity confer a dismal prognosis, despite multimodal treatment. Precision medicine is increasingly advocated to improve survival rates in glioblastoma management; however, conventional neuroimaging techniques are insufficient in providing the detail required for accurate diagnosis of this complex condition.

RECENT FINDINGS

Advanced magnetic resonance imaging allows more comprehensive understanding of the tumour microenvironment. Combining diffusion and perfusion magnetic resonance imaging to create a multiparametric scan enhances diagnostic power and can overcome the unreliability of tumour characterisation by standard imaging. Recent progress in deep learning algorithms establishes their remarkable ability in image-recognition tasks. Integrating these with multiparametric scans could transform the diagnosis and monitoring of patients by ensuring that the entire tumour is captured. As a corollary, radiomics has emerged as a powerful approach to offer insights into diagnosis, prognosis, treatment, and tumour response through extraction of information from radiological scans, and transformation of these tumour characteristics into quantitative data. Radiogenomics, which links imaging features with genomic profiles, has exhibited its ability in characterising glioblastoma, and determining therapeutic response, with the potential to revolutionise management of glioblastoma. The integration of deep learning algorithms into radiogenomic models has established an automated, highly reproducible means to predict glioblastoma molecular signatures, further aiding prognosis and targeted therapy. However, challenges including lack of large cohorts, absence of standardised guidelines and the 'black-box' nature of deep learning algorithms, must first be overcome before this workflow can be applied in clinical practice.

Mechanism of Action of KL-50, a Candidate Imidazotetrazine for the Treatment of Drug-Resistant Brain Cancers

Aberrant DNA repair is a hallmark of cancer, and many tumors display reduced DNA repair capacities that sensitize them to genotoxins. Here, we demonstrate that the differential DNA repair capacities of healthy and transformed tissue may be exploited to obtain highly selective chemotherapies. We show that the novel N3-(2-fluoroethyl)imidazotetrazine "KL-50" is a selective toxin toward tumors that lack the DNA repair protein O6-methylguanine-DNA-methyltransferase (MGMT), which reverses the formation of O6-alkylguanine lesions. We establish that KL-50 generates DNA interstrand cross-links (ICLs) by a multistep process comprising DNA alkylation to generate an O6-(2-fluoroethyl)guanine (O6FEtG) lesion, slow unimolecular displacement of fluoride to form an N1,O6-ethanoguanine (N1,O6EtG) intermediate, and ring-opening by the adjacent cytidine. The slow rate of N1,O6EtG formation allows healthy cells expressing MGMT to reverse the initial O6FEtG lesion before it evolves to N1,O6EtG, thereby suppressing the formation of toxic DNA-MGMT cross-links and reducing the amount of DNA ICLs generated in healthy cells. In contrast, O6-(2-chloroethyl)guanine lesions produced by agents such as lomustine and the N3-(2-chloroethyl)imidazotetrazine mitozolomide rapidly evolve to N1,O6EtG, resulting in the formation of DNA-MGMT cross-links and DNA ICLs in healthy tissue. These studies suggest that careful consideration of the rates of chemical DNA modification and biochemical DNA repair may lead to the identification of other tumor-specific genotoxic agents.

Neuroinflammation in Glioblastoma: Progress and Perspectives

Glioblastoma is the most common and malignant primary brain tumor, with high morbidity and mortality. Despite an aggressive, multimodal treatment regimen, including surgical resection followed by chemotherapy and radiotherapy, the prognosis of glioblastoma patients remains poor. One formidable challenge to advancing glioblastoma therapy is the complexity of the tumor microenvironment. The tumor microenvironment of glioblastoma is a highly dynamic and heterogeneous system that consists of not only cancerous cells but also various resident or infiltrating inflammatory cells. These inflammatory cells not only provide a unique tumor environment for glioblastoma cells to develop and grow but also play important roles in regulating tumor aggressiveness and treatment resistance. Targeting the tumor microenvironment, especially neuroinflammation, has increasingly been recognized as a novel therapeutic approach in glioblastoma. In this review, we discuss the components of the tumor microenvironment in glioblastoma, focusing on neuroinflammation. We discuss the interactions between different tumor microenvironment components as well as their functions in regulating glioblastoma pathogenesis and progression. We will also discuss the anti-tumor microenvironment interventions that can be employed as potential therapeutic targets.

The combination of temozolomide and perifosine synergistically inhibit glioblastoma by impeding DNA repair and inducing apoptosis

Temozolomide (TMZ) is widely utilized as the primary chemotherapeutic intervention for glioblastoma. However, the clinical use of TMZ is limited by its various side effects and resistance to chemotherapy. The present study revealed the synergistic inhibition of glioblastoma through the combined administration of TMZ and perifosine. This combination therapy markedly diminished BRCA1 expression, resulting in the suppression of DNA repair mechanisms. Furthermore, the combination of TMZ and perifosine elicited caspase-dependent apoptosis, decreasing glioblastoma cell viability and proliferation. The observed synergistic effect of this combination therapy on glioblastoma was validated in vivo, as evidenced by the substantial reduction in glioblastoma xenograft growth following combined treatment with TMZ and perifosine. In recurrent glioma patients, higher BRCA1 expression is associated with worse prognosis, especially the ones that received TMZ-treated. These findings underscore the potent antitumor activity of the AKT inhibitor perifosine when combined with TMZ and suggest that this approach is a promising strategy for clinical glioblastoma treatment.

Toxoplasma gondii infection supports the infiltration of T cells into brain tumors

Few T cells infiltrate into primary brain tumors, fundamentally hampering the effectiveness of immunotherapy. We hypothesized that Toxoplasma gondii, a microorganism that naturally elicits a Th1 response in the brain, can promote T cell infiltration into brain tumors despite their immune suppressive microenvironment. Using a mouse genetic model for medulloblastoma, we found that T. gondii infection induced the infiltration of activatable T cells into the tumor mass and led to myeloid cell reprogramming toward a T cell-supportive state, without causing severe health issues in mice. The study provides a concrete foundation for future studies to take advantage of the immune modulatory capacity of T. gondii to facilitate brain tumor immunotherapy.

Single Nucleus Total RNA Sequencing of Formalin-Fixed Paraffin-Embedded Gliomas

Gliomas, the predominant form of brain cancer, comprise diverse malignant subtypes with limited curative therapies available. The insufficient understanding of their molecular diversity and evolutionary processes hinders the advancement of new treatments. Technical complexities associated with formalin-fixed paraffin-embedded (FFPE) clinical samples hinder molecular-level analyses of gliomas. Current single-cell RNA sequencing (scRNA-seq) platforms are inadequate for large-scale clinical applications. In this study, automated snRandom-seq is developed, a high-throughput single-nucleus total RNA sequencing platform optimized for archival FFPE samples. This platform integrates automated single-nucleus isolation and droplet barcoding systems with the random primer-based scRNA-seq chemistry, accommodating a broad spectrum of sample types. The automated snRandom-seq is applied to analyze 116 492 single nuclei from 17 FFPE samples of various glioma subtypes, including rare clinical samples and matched primary-recurrent glioblastomas (GBMs). The study provides comprehensive insights into the molecular characteristics of gliomas at the single-cell level. Abundant non-coding RNAs (ncRNAs) with distinct expression profiles across different glioma clusters and uncovered promising recurrence-related targets and pathways in primary-recurrent GBMs are identified. These findings establish automated snRandom-seq as a robust tool for scRNA-seq of FFPE samples, enabling exploration of molecular diversities and tumor evolution. This platform holds significant implications for large-scale integrative and retrospective clinical research.

A Synopsis of Biomarkers in Glioblastoma: Past and Present

Accounting for 48% of malignant brain tumors in adults, glioblastoma has been of great interest in the last decades, especially in the biomolecular and neurosurgical fields, due to its incurable nature and notable neurological morbidity. The major advancements in neurosurgical technologies have positively influenced the extent of safe tumoral resection, while the latest progress in the biomolecular field of GBM has uncovered new potential therapeutical targets. Although GBM currently has no curative therapy, recent progress has been made in the management of this disease, both from surgical and molecular perspectives. The main current therapeutic approach is multimodal and consists of neurosurgical intervention, radiotherapy, and chemotherapy, mostly with temozolomide. Although most patients will develop treatment resistance and tumor recurrence after surgical removal, biomolecular advancements regarding GBM have contributed to a better understanding of this pathology and its therapeutic management. Over the past few decades, specific biomarkers have been discovered that have helped predict prognosis and treatment responses and contributed to improvements in survival rates.

The Use of Apparent Diffusion Coefficient Values for Differentiating Bevacizumab-Related Cytotoxicity from Tumor Recurrence and Radiation Necrosis in Glioblastoma

OBJECTIVES

Glioblastomas (GBM) are the most common primary invasive neoplasms of the brain. Distinguishing between lesion recurrence and different types of treatment related changes in patients with GBM remains challenging using conventional MRI imaging techniques. Therefore, accurate and precise differentiation between true progression or pseudoresponse is crucial in deciding on the appropriate course of treatment. This retrospective study investigated the potential of apparent diffusion coefficient (ADC) map values derived from diffusion-weighted imaging (DWI) as a noninvasive method to increase diagnostic accuracy in treatment response.

METHODS

A cohort of 21 glioblastoma patients (mean age: 59.2 ± 11.8, 12 Male, 9 Female) that underwent treatment with bevacizumab were selected. The ADC values were calculated from the DWI images obtained from a standardized brain protocol across 1.5-T and 3-T MRI scanners. Ratios were calculated for rADC values. Lesions were classified as bevacizumab-induced cytotoxicity based on characteristic imaging features (well-defined regions of restricted diffusion with persistent diffusion restriction over the course of weeks without tissue volume loss and absence of contrast enhancement). The rADC value was compared to these values in radiation necrosis and recurrent lesions, which were concluded in our prior study. The nonparametric Wilcoxon signed rank test with p < 0.05 was used for significance.

RESULTS

The mean ± SD age of the selected patients was 59.2 ± 11.8. ADC values and corresponding mean rADC values for bevacizumab-induced cytotoxicity were 248.1 ± 67.2 and 0.39 ± 0.10, respectively. These results were compared to the ADC values and corresponding mean rADC values of tumor progression and radiation necrosis. Significant differences between rADC values were observed in all three groups (p < 0.001). Bevacizumab-induced cytotoxicity had statistically significant lower ADC values compared to both tumor recurrence and radiation necrosis.

CONCLUSION

The study demonstrates the potential of ADC values as noninvasive imaging biomarkers for differentiating recurrent glioblastoma from radiation necrosis and bevacizumab-induced cytotoxicity.

MicroRNAs as the pivotal regulators of Temozolomide resistance in glioblastoma

Glioblastoma (GBM) is an aggressive nervous system tumor with a poor prognosis. Although, surgery, radiation therapy, and chemotherapy are the current standard protocol for GBM patients, there is still a poor prognosis in these patients. Temozolomide (TMZ) as a first-line therapeutic agent in GBM can easily cross from the blood-brain barrier to inhibit tumor cell proliferation. However, there is a high rate of TMZ resistance in GBM patients. Since, there are limited therapeutic choices for GBM patients who develop TMZ resistance; it is required to clarify the molecular mechanisms of chemo resistance to introduce the novel therapeutic targets. MicroRNAs (miRNAs) regulate chemo resistance through regulation of drug metabolism, absorption, DNA repair, apoptosis, and cell cycle. In the present review we discussed the role of miRNAs in TMZ response of GBM cells. It has been reported that miRNAs mainly induced TMZ sensitivity by regulation of signaling pathways and autophagy in GBM cells. Therefore, miRNAs can be used as the reliable diagnostic/prognostic markers in GBM patients. They can also be used as the therapeutic targets to improve the TMZ response in GBM cells.

Brain-targeting redox-sensitive micelles for codelivery of TMZ and β-lapachone for glioblastoma therapy

Glioblastoma (GBM) is a central nervous system cancer with high incidence and poor survival rates. Enhancing drug penetration of the blood-brain barrier (BBB) and targeting efficacy is crucial for improving treatment outcomes. In this study, we developed a redox-sensitive targeted nano-delivery system (HCA-A2) for temozolomide (TMZ) and β-lapachone (β-Lapa). This system used hyaluronic acid (HA) as the hydrophilic group, arachidonic acid (CA) as the hydrophobic group, and angiopep-2 (A2) as the targeting group. Control systems included non-redox sensitive (HDA-A2) and non-targeting (HCA) versions. In vitro, HCA-TMZ-Lapa micelles released 100 % of their payload in a simulated tumor microenvironment within 24 h, compared to 43.97 % under normal conditions. HCA-A2 micelles, internalized via clathrin-mediated endocytosis, showed stronger cytotoxicity and better BBB penetration and cellular uptake than controls. In vivo studies demonstrated superior tumor growth inhibition with HCA-A2 micelles, indicating their potential for GBM treatment.

Nanoparticles Coated with Brain Microvascular Endothelial Cell Membranes can Target and Cross the Blood-Brain Barrier to Deliver Drugs to Brain Tumors

The blood-brain barrier (BBB) contains tightly connected brain microvascular endothelial cells (BMECs) that hinder drug delivery to the brain, which makes brain tumors difficult to treat. Previous studies have shown that nanoparticles coated with tumor cell membranes selectively target their homologous tumors. Therefore, this study investigated whether bEnd.3-line BMEC membrane-coated nanoparticles with poly(lactide-co-glycolide)-poly(ethylene glycol)-based doxorubicin-loaded cores (BM-PDs) can be used to target BMECs and cross the BBB. In vitro, the BM-PDs effectively target BMECs and cross a BBB model. The BM-PDs enter the BMECs via macropinocytosis, clathrin-mediated endocytosis, caveolin-mediated endocytosis, and membrane fusion, which result in excellent cellular uptake. The BM-PDs also show excellent cellular uptake in brain tumor cells. In vivo, the BM-PDs target BMECs, cross the BBB, accumulate in brain tumors, and efficiently kill tumor cells. Therefore, the proposed strategy has great therapeutic potential owing to its ability to cross the BBB to reach brain tumors.

Multi-scale brain attributes contribute to the distribution of diffuse glioma subtypes

Gliomas are primary brain tumors and are among the most malignant types. Adult-type diffuse gliomas can be classified based on their histological and molecular signatures as IDH-wildtype glioblastoma, IDH-mutant astrocytoma, and IDH-mutant and 1p/19q-codeleted oligodendroglioma. Recent studies have shown that each subtype of glioma has its own specific distribution pattern. However, the mechanisms underlying the specific distributions of glioma subtypes are not entirely clear despite partial explanations such as cell origin. To investigate the impact of multi-scale brain attributes on glioma distribution, we constructed cumulative frequency maps for diffuse glioma subtypes based on T1w structural images and evaluated the spatial correlation between tumor frequency and diverse brain attributes, including postmortem gene expression, functional connectivity metrics, cerebral perfusion, glucose metabolism, and neurotransmitter signaling. Regression models were constructed to evaluate the contribution of these factors to the anatomic distribution of different glioma subtypes. Our findings revealed that the three different subtypes of gliomas had distinct distribution patterns, showing spatial preferences toward different brain environmental attributes. Glioblastomas were especially likely to occur in regions enriched with synapse-related pathways and diverse neurotransmitter receptors. Astrocytomas and oligodendrogliomas preferentially occurred in areas enriched with genes associated with neutrophil-mediated immune responses. The functional network characteristics and neurotransmitter distribution also contributed to oligodendroglioma distribution. Our results suggest that different brain transcriptomic, neurotransmitter, and connectomic attributes are the factors that determine the specific distributions of glioma subtypes. These findings highlight the importance of bridging diverse scales of biological organization when studying neurological dysfunction.

A targetable PRR11-DHODH axis drives ferroptosis- and temozolomide-resistance in glioblastoma

Temozolomide (TMZ) is a widely utilized chemotherapy treatment for patients with glioblastoma (GBM), although drug resistance constitutes a major therapeutic hurdle. Emerging evidence suggests that ferroptosis-mediated therapy could offer an appropriate alternative treatment option against cancer cells that are resistant to certain drugs. However, recurrent gliomas display robust ferroptosis resistance, although the precise mechanism of resistance remains elusive. In the present work, we report that proline rich protein 11 (PRR11) depletion significantly sensitizes GBM cells to TMZ by inducing ferroptosis. Mechanistically, PRR11 directly binds to and stabilizes dihydroorotate dehydrogenase (DHODH), which leads to glioma ferroptosis-resistant in a DHODH-dependent manner in vivo and in vitro. Furthermore, PRR11 inhibits HERC4 and DHODH binding, by suppressing the recruitment of E3 ubiquitin ligase HERC4 and polyubiquitination degradation of DHODH at the K306 site, which maintains DHODH protein stability. Importantly, downregulated PRR11 increases lipid peroxidation and alters DHODH-mediated mitochondrial morphology, thereby promoting ferroptosis and increasing TMZ chemotherapy sensitivity. In conclusion, our results reveal a mechanism via which PRR11 drives ferroptosis resistance and identifies ferroptosis induction and TMZ as an attractive combined therapeutic strategy for GBM.

Clinical analysis of the efficacy of radiation therapy for primary high-grade gliomas guided by biological rhythms

OBJECTIVE

High-grade glioma (HGG) patients frequently encounter treatment resistance and relapse, despite numerous interventions seeking enhanced survival outcomes yielding limited success. Consequently, this study, rooted in our prior research, aimed to ascertain whether leveraging circadian rhythm phase attributes could optimize radiotherapy results.

METHODS

In this retrospective analysis, we meticulously selected 121 HGG cases with synchronized rhythms through Cosinor analysis. Post-surgery, all subjects underwent standard radiotherapy alongside Temozolomide chemotherapy. Random allocation ensued, dividing patients into morning (N = 69) and afternoon (N = 52) radiotherapy cohorts, enabling a comparison of survival and toxicity disparities.

RESULTS

The afternoon radiotherapy group exhibited improved overall survival (OS) and progression-free survival (PFS) relative to the morning cohort. Notably, median OS extended to 25.6 months versus 18.5 months, with P = 0.014, with median PFS at 20.6 months versus 13.3 months, with P = 0.022, post-standardized radiotherapy. Additionally, lymphocyte expression levels in the afternoon radiation group 32.90(26.10, 39.10) significantly exceeded those in the morning group 31.30(26.50, 39.20), with P = 0.032.

CONCLUSIONS

This study underscores the markedly prolonged average survival within the afternoon radiotherapy group. Moreover, lymphocyte proportion demonstrated a notable elevation in the afternoon group. Timely and strategic adjustments of therapeutic interventions show the potential to improve therapeutic efficacy, while maintaining vigilant systemic immune surveillance. A comprehensive grasp of physiological rhythms governing both the human body and tumor microenvironment can refine treatment efficacy, concurrently curtailing immune-related damage-a crucial facet of precision medicine.

Glioblastoma and brain connectivity: the need for a paradigm shift

Despite substantial advances in cancer treatment, for patients with glioblastoma prognosis remains bleak. The emerging field of cancer neuroscience reveals intricate functional interplays between glioblastoma and the cellular architecture of the brain, encompassing neurons, glia, and vessels. New findings underscore the role of structural and functional connections within hierarchical networks, known as the connectome. These connections contribute to the location, spread, and recurrence of a glioblastoma, and a patient's overall survival, revealing a complex interplay between the tumour and the CNS. This mounting evidence prompts a paradigm shift, challenging the perception of glioblastomas as mere foreign bodies within the brain. Instead, these tumours are intricately woven into the structural and functional fabric of the brain. This radical change in thinking holds profound implications for the understanding and treatment of glioblastomas, which could unveil new prognostic factors and surgical strategies and optimise radiotherapy. Additionally, a connectivity approach suggests that non-invasive brain stimulation could disrupt pathological neuron-glioma interactions within specific networks.

Construction and Validation of Nomograms for Predicting Overall Survival and Cancer-Specific Survival in Patients with Primary Anaplastic Oligodendroglioma

OBJECTIVE

Anaplastic oligodendroglioma (AOD) is a rare high-grade central nervous system tumor. The current research on prognostic prediction of AOD remains limited. This study aimed to identify prognostic factors and establish the nomograms to predict overall survival (OS) and cancer-specific survival (CSS) for patients with AOD.

METHODS

Patients diagnosed with AOD between 1992 and 2020 were extracted from the Surveillance, Epidemiology, and End Result database. We performed univariate and multivariate Cox regression analyses to identify independent prognostic factors based on the training group. Kaplan-Meier survival curves were used to compare the impact of various independent factors on patient prognosis. For OS and CSS, the nomograms were constructed and verified by the validation group. Harrell''s concordance index, receiver operating characteristic curves, calibration curves, and decision curve analyses were used to assess the discrimination, consistency, and clinical value of the nomograms.

RESULTS

A total of 1202 AOD patients were enrolled, being randomly divided into training (n = 841) and validation (n = 361) groups (7:3 ratio). Univariate and multivariate Cox analysis identified 4 significant independent factors (tumor site, age, surgery, and chemotherapy). For OS and CSS, Harrell''s concordance index were 0.731 (0.705-0.757) and 0.728 (0.701-0.754) in the training group, 0.688 (0.646-0.731) and 0.684 (0.639-0.729) in the validation group, respectively. Receiver operating characteristic curves and Calibration curves showed good discrimination and consistency, respectively. In addition, the decision curve analyses curves showed the nomograms have good clinical benefits.

CONCLUSIONS

We successfully established the nomograms to predict the OS and CSS for AOD patients. The nomograms showed good performance in prognostic prediction, assisting clinicians in evaluating patient prognosis and personalizing treatment plans.

A Manganese-Based Nanodriver Coordinates Tumor Prevention and Suppression through STING Activation in Glioblastoma

Glioblastoma (GBM), the most prevalent and aggressive primary malignant brain tumor, exhibits profound immunosuppression and demonstrates a low response rate to current immunotherapy strategies. Manganese cations (Mn2+) directly activate the cGAS/STING pathway and induce the unique catalytic synthesis of 2'3'-cGAMP to facilitate type I IFN production, thereby enhancing innate immunity. Here, a telodendrimer and Mn2+-based nanodriver (PLHM) with a small size is developed, which effectively target lymph nodes through the blood circulation and exhibit tumor-preventive effects at low doses of Mn2+ (3.7 mg kg-1). On the other hand, the PLHM nanodriver also exhibits apparent antitumor effects in GBM-bearing mice via inducing in vivo innate immune responses. The combination of PLHM with doxorubicin nanoparticles (PLHM-DOX NPs) results in superior inhibition of tumor growth in GBM-bearing mice due to the synergistic potentiation of STING pathway functionality by Mn2+ and the presence of cytoplasmic DNA. These findings demonstrate that PLHM-DOX NPs effectively stimulate innate immunity, promote dendritic cell maturation, and orchestrate cascaded infiltration of CD8 cytotoxic T lymphocytes within glioblastomas characterized by low immunogenicity. These nanodivers chelated with Mn2+ show promising potential for tumor prevention and antitumor effects on glioblastoma by activating the STING pathway.

Generation of B7-H3 isoform regulated by ANXA2/NSUN2/YBX1 axis in human glioma

In recent years, in the development of emerging immunotherapy, B7-H3 is also termed as CD276 and has become a novel chimeric antigen receptor (CAR)-T target against glioma and other tumours, and aroused extensive attention. However, B7-H3 has three isoforms (2, 3 and 4Ig) with the controversial expression and elusive function in tumour especially glioma. The current study mainly focuses on the regulatory factors and related mechanisms of generation of different B7-H3 isoforms. First, we have determined that 2Ig is dominant in glioma with high malignancy, and 4Ig is widely expressed, whereas 3Ig shows negative expression in all glioma. Next, we have further found that RNA binding protein annexin A2 (ANXA2) is essential for B7-H3 isoform maintenance, but fail to determine the choice of 4Ig or 2Ig. RNA methyltransferase NOP2/Sun RNA methyltransferase 2 (NSUN2) and 5-methylcytosine reader Y-box binding protein 1 (YBX1) facilitate the production of 2Ig. Our findings have uncovered a series of factors (ANXA2/NSUN2/YBX1) that can determine the alternative generation of different isoforms of B7-H3 in glioma. Our result aims to help peers gain a clearer understanding of the expression and regulatory mechanisms of B7H3 in tumour patients, and to provide better strategies for designing B7H3 as a target in immunotherapy.

Biological Activity of Natural and Synthetic Peptides as Anticancer Agents

Cancer is one of the leading causes of morbidity and death worldwide, making it a serious global health concern. Chemotherapy, radiotherapy, and surgical treatment are the most used conventional therapeutic approaches, although they show several side effects that limit their effectiveness. For these reasons, the discovery of new effective alternative therapies still represents an enormous challenge for the treatment of tumour diseases. Recently, anticancer peptides (ACPs) have gained attention for cancer diagnosis and treatment. ACPs are small bioactive molecules which selectively induce cancer cell death through a variety of mechanisms such as apoptosis, membrane disruption, DNA damage, immunomodulation, as well as inhibition of angiogenesis, cell survival, and proliferation pathways. ACPs can also be employed for the targeted delivery of drugs into cancer cells. With over 1000 clinical trials using ACPs, their potential for application in cancer therapy seems promising. Peptides can also be utilized in conjunction with imaging agents and molecular imaging methods, such as MRI, PET, CT, and NIR, improving the detection and the classification of cancer, and monitoring the treatment response. In this review we will provide an overview of the biological activity of some natural and synthetic peptides for the treatment of the most common and malignant tumours affecting people around the world.

Network pharmacology-based investigation of the effects of Shenqi Fuzheng injection on glioma proliferation and migration via the SRC/PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

In the clinic, Shenqi Fuzheng Injection (SFI) is used as an adjuvant for cancer chemotherapy. However, the molecular mechanism is unclear.

AIM OF THE STUDY

We screened potential targets of SFI action on gliomas by network pharmacology and performed experiments to validate possible molecular mechanisms against gliomas.

MATERIALS AND METHODS

We consulted relevant reports on the SFI and glioma incidence from PubMed and Web of Science and focused on the mechanism through which the SFI inhibits glioma. According to the literature, two primary SFI components-Codonopsis pilosula (Franch.) Nannf. and Astragalus membranaceus (Fisch.) Bunge-have been found. All plant names have been sourced from "The Plant List" (www.theplantlist.org). The cell lines U87, T98G and GL261 were used in this study. The inhibitory effects of SFI on glioma cells U87 and T98G were detected by CCK-8 assay, EdU, plate cloning assay, scratch assay, Transwell assay, immunofluorescence, flow cytometry and Western blot. A subcutaneous tumor model of C57BL/6 mice was constructed using GL261 cells, and the SFI was evaluated by HE staining and immunohistochemistry. The targets of glioma and the SFI were screened using network pharmacology.

RESULTS

A total of 110 targets were enriched, and a total of 26 major active components in the SFI were investigated. There were a total of 3,343 targets for gliomas, of which 79 targets were shared between the SFI and glioma tissues. SFI successfully prevented proliferation and caused cellular S-phase blockage in U87 and T98G cells, thus decreasing their growth. Furthermore, SFI suppressed cell migration by downregulating EMT marker expression. According to the results of the in vivo tests, the SFI dramatically decreased the development of tumors in a transplanted tumour model. Network pharmacological studies revealed that the SRC/PI3K/AKT signaling pathway may be the pathway through which SFI exerts its anti-glioma effects.

CONCLUSIONS

The findings revealed that the SRC/PI3K/AKT signaling pathway may be involved in the mechanism through which SFI inhibits the proliferation and migration of glioma cells.

Network-Based Transcriptome Analysis Reveals FAM3C as a Novel Potential Biomarker for Glioblastoma

Glioblastoma (GBM) is the most common form of malignant primary brain tumor with a high mortality rate. The aim of the present study was to investigate the clinical significance of Family with Sequence Similarity 3, Member C, FAM3C, in GBM using bioinformatic-integrated analysis. First, we performed the transcriptomic integration analysis to assess the expression profile of FAM3C in GBM using several data sets (RNA-sequencing and scRNA-sequencing), which were obtained from TCGA and GEO databases. By using the STRING platform, we investigated FAM3C-coregulated genes to construct the protein-protein interaction network. Next, Metascape, Enrichr, and CIBERSORT databases were used. We found FAM3C high expression in GBM with poor survival rates. Further, we observed, via FAM3C coexpression network analysis, that FAM3C plays key roles in several hallmarks of cancer. Surprisingly, we also highlighted five FAM3C‑coregulated genes overexpressed in GBM. Specifically, we demonstrated the association between the high expression of FAM3C and the abundance of the different immune cells, which may markedly worsen GBM prognosis. For the first time, our findings suggest that FAM3C not only can be a new emerging biomarker with promising therapeutic values to GBM patients but also gave a new insight into a potential resource for future GBM studies.

Incidence of venous thromboembolism and bleeding in patients with malignant central nervous system neoplasm: Systematic review and meta-analysis

Central nervous system (CNS) malignant neoplasms may lead to venous thromboembolism (VTE) and bleeding, which result in rehospitalization, morbidity and mortality. We aimed to assess the incidence of VTE and bleeding in this population.

METHODS

This systematic review and meta-analysis (PROSPERO CRD42023423949) were based on a standardized search of PubMed, Virtual Health Library and Cochrane (n = 1653) in July 2023. After duplicate removal, data screening and collection were conducted by independent reviewers. The combined rates and 95% confidence intervals for the incidence of VTE and bleeding were calculated using the random effects model with double arcsine transformation. Subgroup analyses were performed based on sex, age, income, and type of tumor. Heterogeneity was calculated using Cochran's Q test and I2 statistics. Egger's test and funnel graphs were used to assess publication bias.

RESULTS

Only 36 studies were included, mainly retrospective cohorts (n = 30, 83.3%) from North America (n = 20). Most studies included were published in high-income countries. The sample size of studies varied between 34 and 21,384 adult patients, mostly based on gliomas (n = 30,045). For overall malignant primary CNS neoplasm, the pooled incidence was 13.68% (95%CI 9.79; 18.79) and 11.60% (95%CI 6.16; 18.41) for VTE and bleeding, respectively. The subgroup with elderly people aged 60 or over had the highest incidence of VTE (32.27% - 95%CI 14.40;53.31). The studies presented few biases, being mostly high quality. Despite some variability among the studies, we observed consistent results by performing sensitivity analysis, which highlight the robustness of our findings.

CONCLUSIONS

Our study showed variability in the pooled incidence for both overall events and subgroup analyses. It was highlighted that individuals over 60 years old or diagnosed with GBM had a higher pooled incidence of VTE among those with overall CNS malignancies. It is important to note that the results of this meta-analysis refer mainly to studies carried out in high-income countries. This highlights the need for additional research in Latin America, and low- and middle-income countries.

TRIM37 interacts with EZH2 to epigenetically suppress PTCH1 and regulate stemness in glioma stem cells through sonic hedgehog pathway

BACKGROUND

Glioma stem cells (GSCs), which are known for their therapy resistance, play a substantial role in treatment inefficacy for glioblastoma multiforme (GBM). TRIM37, a member of the tripartite motif (TRIM) protein family initially linked to a rare growth disorder, has been recognized for its oncogenic role. However, the mechanism by which TRIM37 regulates tumor growth in glioma and GSCs is unclear.

METHODS

For the in vitro experiments, gene expression was measured by western blotting, RT-qPCR, and immunofluorescence. Cell viability was detected by CCK-8, and cell apoptosis was detected by flow cytometry. The interaction between Enhancer of Zeste Homolog 2 (EZH2) and TRIM37 was verified by co-immunoprecipitation (Co-IP). The interaction between EZH2 and the PTCH1 promoter was verified using dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP). For the in vivo experiments, an orthotopically implanted glioma mouse model was used to validate tumor growth.

RESULTS

The expression of TRIM37 is higher in GSCs compared with matched non-GSCs. TRIM37 knockdown promotes apoptosis, decreased stemness in GSCs, and reduces tumor growth in GSCs xenografts of nude mice. TRIM37 and EZH2 co-localize in the nucleus and interact with each other. TRIM37 knockdown or EZH2 inhibition downregulates the protein expressions associated with the Sonic Hedgehog (SHH) pathway. EZH2 epigenetically downregulates PTCH1 to activate SHH pathway in GSCs.

CONCLUSIONS

TRIM37 maintains the cell growth and stemness in GSCs through the interaction with EZH2. EZH2 activates SHH stem cell signaling pathway by downregulating the expression of SHH pathway suppressor PTCH1. Our findings suggest that TRIM37 may be a potential therapeutic target for GBM.

Decoding the tumour-modulatory roles of LIMK2

LIM domains kinase 2 (LIMK2) is a 72 kDa protein that regulates actin and cytoskeleton reorganization. Once phosphorylated by its upstream activator (ROCK1), LIMK2 can phosphorylate cofilin to inactivate it. This relieves the levering stress on actin and allows polymerization to occur. Actin rearrangement is essential in regulating cell cycle progression, apoptosis, and migration. Dysregulation of the ROCK1/LIMK2/cofilin pathway has been reported to link to the development of various solid cancers such as breast, lung, and prostate cancer and liquid cancer like leukemia. This review aims to assess the findings from multiple reported in vitro, in vivo, and clinical studies on the potential tumour-regulatory role of LIMK2 in different human cancers. The findings of the selected literature unraveled that activated AKT, EGF, and TGF-β pathways can upregulate the activities of the ROCK1/LIMK2/cofilin pathway. Besides cofilin, LIMK2 can modulate the cellular levels of other proteins, such as TPPP1, to promote microtubule polymerization. The tumour suppressor protein p53 can transactivate LIMK2b, a splice variant of LIMK2, to induce cell cycle arrest and allow DNA repair to occur before the cell enters the next phase of the cell cycle. Additionally, several non-coding RNAs, such as miR-135a and miR-939-5p, could also epigenetically regulate the expression of LIMK2. Since the expression of LIMK2 is dysregulated in several human cancers, measuring the tissue expression of LIMK2 could potentially help diagnose cancer and predict patient prognosis. As LIMK2 could play tumour-promoting and tumour-inhibiting roles in cancer development, more investigation should be conducted to carefully evaluate whether introducing a LIMK2 inhibitor in cancer patients could slow cancer progression without posing clinical harms.

Progress of nanoparticle drug delivery system for the treatment of glioma

Gliomas are typical malignant brain tumours affecting a wide population worldwide. Operation, as the common treatment for gliomas, is always accompanied by postoperative drug chemotherapy, but cannot cure patients. The main challenges are chemotherapeutic drugs have low blood-brain barrier passage rate and a lot of serious adverse effects, meanwhile, they have difficulty targeting glioma issues. Nowadays, the emergence of nanoparticles (NPs) drug delivery systems (NDDS) has provided a new promising approach for the treatment of gliomas owing to their excellent biodegradability, high stability, good biocompatibility, low toxicity, and minimal adverse effects. Herein, we reviewed the types and delivery mechanisms of NPs currently used in gliomas, including passive and active brain targeting drug delivery. In particular, we primarily focused on various hopeful types of NPs (such as liposome, chitosan, ferritin, graphene oxide, silica nanoparticle, nanogel, neutrophil, and adeno-associated virus), and discussed their advantages, disadvantages, and progress in preclinical trials. Moreover, we outlined the clinical trials of NPs applied in gliomas. According to this review, we provide an outlook of the prospects of NDDS for treating gliomas and summarise some methods that can enhance the targeting specificity and safety of NPs, like surface modification and conjugating ligands and peptides. Although there are still some limitations of these NPs, NDDS will offer the potential for curing glioma patients.

Hypoxia-induced activation of HIF-1alpha/IL-1beta axis in microglia promotes glioma progression via NF-κB-mediated upregulation of heparanase expression

BACKGROUND

Glioma is a common tumor that occurs in the brain and spinal cord. Hypoxia is a crucial feature of the tumor microenvironment. Tumor-associated macrophages/microglia play a crucial role in the advancement of glioma. This study aims to illuminate the detailed mechanisms by which hypoxia regulates microglia and, consequently, influences the progression of glioma.

METHODS

The glioma cell viability and proliferation were analyzed by cell counting kit-8 assay and 5-ethynyl-2'-deoxyuridine assay. Wound healing assay and transwell assay were implemented to detect glioma cell migration and invasion, respectively. Enzyme-linked immunosorbent assay was conducted to detect protein levels in cell culture medium. The protein levels in glioma cells and tumor tissues were evaluated using western blot analysis. The histological morphology of tumor tissue was determined by hematoxylin-eosin staining. The protein expression in tumor tissues was determined using immunohistochemistry. Human glioma xenograft in nude mice was employed to test the influence of hypoxic microglia-derived interleukin-1beta (IL-1β) and heparanase (HPSE) on glioma growth in vivo.

RESULTS

Hypoxic HMC3 cells promoted proliferation, migration, and invasion abilities of U251 and U87 cells by secreting IL-1β, which was upregulated by hypoxia-induced activation of hypoxia inducible factor-1alpha (HIF-1α). Besides, IL-1β from HMC3 cells promoted glioma progression and caused activation of nuclear factor-κB (NF-κB) and upregulation of HPSE in vivo. We also confirmed that IL-1β facilitated HPSE expression in U251 and U87 cells by activating NF-κB. Hypoxic HMC3 cells-secreted IL-1β facilitated the proliferation, migration, and invasion of U251 and U87 cells via NF-κB-mediated upregulation of HPSE expression. Finally, we revealed that silencing HPSE curbed the proliferation and metastasis of glioma in mice.

CONCLUSION

Hypoxia-induced activation of HIF-1α/IL-1β axis in microglia promoted glioma progression via NF-κB-mediated upregulation of HPSE expression.

Bedside ultrasound-assisted puncture and drainage under local anesthesia: A novel approach for early post-operative space-occupying tumor bed cysts of glioma resection

OBJECTIVES

To investigate the causes of space-occupying tumor bed cysts formed early after glioma resection by measuring the osmotic pressure gradient between cystic fluid, serum, and cerebrospinal fluid (CSF) and propose a new method of bedside ultrasound-assisted puncture and drainage (UAP&D) under local anesthesia for treatment.

METHODS

Bedside UAP&D under local anesthesia was performed through a burr hole on the skull flap.Following a successful puncture, cystic fluid was collected, while blood and CSF were obtained through vein and lumbar puncture, respectively. The osmotic pressure of all fluids collected was measured. The appearance, biochemical composition, and results of microbial culture of cystic fluid and CSF were analyzed. Within 24 h after UAP&D, a CT examination and Glasgow coma scale (GCS) were assessed.

RESULTS

The osmotic pressure of cystic fluid was higher than that of serum and CSF. White blood cell count and protein concentration were higher in the cystic fluid compared to the CSF. Conversely, the concentration of chloride ions and glucose were lower. CT scan confirmed the correct placement of the cysts' drainage tube and that the cysts' volume decreased significantly with continued drainage. Accompanied by a reduction in the volume of cysts, there were significant improvements in GCS score within 24 h after UAP&D. All drainage tubes were removed within 2-5 days, and no puncture tract hemorrhage or infection was observed.

CONCLUSION

The osmotic pressure gradient between cystic fluid, serum, and CSF caused the formation of early post-operative space-occupying tumor bed cysts for glioma. UAP&D aligns with the concept that micro-invasive neurosurgery is an effective treatment method for such cysts.

SRSF9 promotes cell proliferation and migration of glioblastoma through enhancing CDK1 expression

BACKGROUND

Glioblastoma (GBM) is a highly aggressive and prevalent brain tumor that poses significant challenges in treatment. SRSF9, an RNA-binding protein, is essential for cellular processes and implicated in cancer progression. Yet, its function and mechanism in GBM need clarification.

METHODS

Bioinformatics analysis was performed to explore differential expression of SRSF9 in GBM and its prognostic relevance to glioma patients. SRSF9 and CDK1 expression in GBM cell lines and patients' tissues were quantified by RT-qPCR, Western blot or immunofluorescence assay. The role of SRSF9 in GBM cell proliferation and migration was assessed by MTT, Transwell and colony formation assays. Additionally, transcriptional regulation of CDK1 by SRSF9 was investigated using ChIP-PCR and dual-luciferase assays.

RESULTS

The elevated SRSF9 expression correlates to GBM stages and poor survival of glioma patients. Through gain-of-function and loss-of-function strategies, SRSF9 was demonstrated to promote proliferation and migration of GBM cells. Bioinformatics analysis showed that SRSF9 has an impact on cell growth pathways including cell cycle checkpoints and E2F targets. Mechanistically, SRSF9 appears to bind to the promoter of CDK1 gene and increase its transcription level, thus promoting GBM cell proliferation.

CONCLUSIONS

These findings uncover the cellular function of SRSF9 in GBM and highlight its therapeutic potential for GBM.

Crebanine, an aporphine alkaloid, induces cancer cell apoptosis through PI3K-Akt pathway in glioblastoma multiforme

Glioblastoma multiforme (GBM) is one of the most prevalent and lethal primary central nervous system malignancies. GBM is notorious for its high rates of recurrence and therapy resistance and the PI3K/Akt pathway plays a pivotal role in its malignant behavior. Crebanine (CB), an alkaloid capable of penetrating the blood-brain barrier (BBB), has been shown to have inhibitory effects on proinflammatory molecules and multiple cancer cell lines via pathways such as PI3K/Akt. This study aims to investigate the efficacy and mechanisms of CB treatment on GBM. It is the first study to elucidate the anti-tumor role of CB in GBM, providing new possibilities for GBM therapy. Through a series of experiments, we demonstrate the significant anti-survival, anti-clonogenicity, and proapoptotic effects of CB treatment on GBM cell lines. Next-generation sequencing (NGS) is also conducted and provides a complete list of significant changes in gene expression after treatment, including genes related to apoptosis, the cell cycle, FoxO, and autophagy. The subsequent protein expressions of the upregulation of apoptosis and downregulation of PI3K/Akt are further proved. The clinical applicability of CB to GBM treatment could be high for its BBB-penetrating feature, significant induction of apoptosis, and blockage of the PI3K/Akt pathway. Future research is needed using in vivo experiments and other therapeutic pathways shown in NGS for further clinical or in vivo studies.

TRIM24 Cooperates with Ras Mutation to Drive Glioma Progression through snoRNA Recruitment of PHAX and DNA-PKcs

The factors driving glioma progression remain poorly understood. Here, the epigenetic regulator TRIM24 is identified as a driver of glioma progression, where TRIM24 overexpression promotes HRasV12 anaplastic astrocytoma (AA) progression into epithelioid GBM (Ep-GBM)-like tumors. Co-transfection of TRIM24 with HRasV12 also induces Ep-GBM-like transformation of human neural stem cells (hNSCs) with tumor protein p53 gene (TP53) knockdown. Furthermore, TRIM24 is highly expressed in clinical Ep-GBM specimens. Using single-cell RNA-sequencing (scRNA-Seq), the authors show that TRIM24 overexpression impacts both intratumoral heterogeneity and the tumor microenvironment. Mechanically, HRasV12 activates phosphorylated adaptor for RNA export (PHAX) and upregulates U3 small nucleolar RNAs (U3 snoRNAs) to recruit Ku-dependent DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Overexpressed TRIM24 is also recruited by PHAX to U3 snoRNAs, thereby facilitating DNA-PKcs phosphorylation of TRIM24 at S767/768 residues. Phosphorylated TRIM24 induces epigenome and transcription factor network reprogramming and promotes Ep-GBM-like transformation. Targeting DNA-PKcs with the small molecule inhibitor NU7441 synergizes with temozolomide to reduce Ep-GBM tumorigenicity and prolong animal survival. These findings provide new insights into the epigenetic regulation of Ep-GBM-like transformation and suggest a potential therapeutic strategy for patients with Ep-GBM.

State of the Art in Low-Grade Glioma Management: Insights From Isocitrate Dehydrogenase and Beyond

Low-grade gliomas present a formidable challenge in neuro-oncology because of the challenges imposed by the blood-brain barrier, predilection for the young adult population, and propensity for recurrence. In the past two decades, the systematic examination of genomic alterations in adults and children with primary brain tumors has uncovered profound new insights into the pathogenesis of these tumors, resulting in more accurate tumor classification and prognostication. It also identified several common recurrent genomic alterations that now define specific brain tumor subtypes and have provided a new opportunity for molecularly targeted therapeutic intervention. Adult-type diffuse low-grade gliomas are frequently associated with mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2), resulting in production of 2-hydroxyglutarate, an oncometabolite important for tumorigenesis. Recent studies of IDH inhibitors have yielded promising results in patients at early stages of disease with prolonged progression-free survival (PFS) and delayed time to radiation and chemotherapy. Pediatric-type gliomas have high rates of alterations in BRAF, including BRAF V600E point mutations or BRAF-KIAA1549 rearrangements. BRAF inhibitors, often combined with MEK inhibitors, have resulted in radiographic response and improved PFS in these patients. This article reviews emerging approaches to the treatment of low-grade gliomas, including a discussion of targeted therapies and how they integrate with the current treatment modalities of surgical resection, chemotherapy, and radiation.

Heat-inducible CAR-T overcomes adverse mechanical tumor microenvironment in a 3D bioprinted glioblastoma model

Glioblastoma (GBM) presents a significant therapeutic challenge due to the limited efficacy of existing treatments. Chimeric antigen receptor (CAR) T-cell therapy offers promise, but its potential in solid tumors like GBM is undermined by the physical barrier posed by the extracellular matrix (ECM). To address the inadequacies of traditional 2D cell culture, animal models, and Matrigel-based 3D culture in mimicking the mechanical characteristics of tumor tissues, we employed biomaterials and digital light processing-based 3D bioprinting to fabricate biomimetic tumor models with finely tunable ECM stiffness independent of ECM composition. Our results demonstrated that increased material stiffness markedly impeded CAR-T cell penetration and tumor cell cytotoxicity in GBM models. The 3D bioprinted models enabled us to examine the influence of ECM stiffness on CAR-T cell therapy effectiveness, providing a clinically pertinent evaluation tool for CAR-T cell development in stiff solid tumors. Furthermore, we developed an innovative heat-inducible CAR-T cell therapy, effectively overcoming the challenges posed by the stiff tumor microenvironment.

Sphingolipid Signaling and Complement Activation in Glioblastoma: A Promising Avenue for Therapeutic Intervention

Glioblastoma is the most common and aggressive type of malignant brain tumor with a poor prognosis due to the lack of effective treatment options. Therefore, new treatment options are required. Sphingolipids are essential components of the cell membrane, while complement components are integral to innate immunity, and both play a critical role in regulating glioblastoma survival signaling. This review focuses on recent studies investigating the functional roles of sphingolipid metabolism and complement activation signaling in glioblastoma. It also discusses how targeting these two systems together may emerge as a novel therapeutic approach.

Image-based assessment of natural killer cell activity against glioblastoma stem cells

Glioblastoma (GBM) poses a significant challenge in oncology and stands as the most aggressive form of brain cancer. A primary contributor to its relentless nature is the stem-like cancer cells, called glioblastoma stem cells (GSCs). GSCs have the capacity for self-renewal and tumorigenesis, leading to frequent GBM recurrences and complicating treatment modalities. While natural killer (NK) cells exhibit potential in targeting and eliminating stem-like cancer cells, their efficacy within the GBM microenvironment is limited due to constrained infiltration and function. To address this limitation, novel investigations focusing on boosting NK cell activity against GSCs are imperative. This study presents two streamlined image-based assays assessing NK cell migration and cytotoxicity towards GSCs. It details protocols and explores the strengths and limitations of these methods. These assays could aid in identifying novel targets to enhance NK cell activity towards GSCs, facilitating the development of NK cell-based immunotherapy for improved GBM treatment.

AS1411 binds to nucleolin via its parallel structure and disrupts the exos-miRNA-27a-mediated reciprocal activation loop between glioma and astrocytes

The interaction between glioma cells and astrocytes promotes the proliferation of gliomas. Micro-RNAs (miRNAs) carried by astrocyte exosomes (exos) may be involved in this process, but the mechanism remains unclear. The oligonucleotide AS1411, which consists of 26 bases and has a G-quadruplex structure, is an aptamer that targets nucleolin. In this study, we demonstrate exosome-miRNA-27a-mediated cross-activation between astrocytes and glioblastoma and show that AS1411 reduces astrocytes' pro-glioma activity. The enhanced affinity of AS1411 toward nucleolin is attributed to its G-quadruplex structure. After binding to nucleolin, AS1411 inhibits the entry of the NF-κB pathway transcription factor P65 into the nucleus, then downregulates the expression of miRNA-27a in astrocytes surrounding gliomas. Then, AS1411 downregulates astrocyte exosome-miRNA-27a and upregulates the expression of INPP4B, the target gene of miRNA-27a in gliomas, thereby inhibiting the PI3K/AKT pathway and inhibiting glioma proliferation. These results were verified in mouse orthotopic glioma xenografts and human glioma samples. In conclusion, the parallel structure of AS1411 allows it to bind to nucleolin and disrupt the exosome-miRNA-27a-mediated reciprocal activation loop between glioma cells and astrocytes. Our results may help in the development of a novel approach to therapeutic modulation of the glioma microenvironment.

HAS2 facilitates glioma cell malignancy and suppresses ferroptosis in an FZD7-dependent manner

Glioma is the most common malignant tumor in the central nervous system, and it is crucial to uncover the factors that influence prognosis. In this study, we utilized Mfuzz to identify a gene set that showed a negative correlation with overall survival in patients with glioma. Gene Ontology (GO) enrichment analyses were then undertaken to gain insights into the functional characteristics and pathways associated with these genes. The expression distribution of Hyaluronan Synthase 2 (HAS2) was explored across multiple datasets, revealing its expression patterns. In vitro and in vivo experiments were carried out through gene knockdown and overexpression to validate the functionality of HAS2. Potential upstream transcription factors of HAS2 were predicted using transcriptional regulatory databases, and these predictions were experimentally validated using ChIP-PCR and dual-luciferase reporter gene assays. The results showed that elevated expression of HAS2 in glioma indicates poor prognosis. HAS2 was found to play a role in activating an antiferroptosis pathway in glioma cells. Inhibiting HAS2 significantly increased cellular sensitivity to ferroptosis-inducing agents. Finally, we determined that the oncogenic effect of HAS2 is mediated by the key receptor of the WNT pathway, FZD7.

TUFM in health and disease: exploring its multifaceted roles

The nuclear-encoded mitochondrial protein Tu translation elongation factor, mitochondrial (TUFM) is well-known for its role in mitochondrial protein translation. Originally discovered in yeast, TUFM demonstrates significant evolutionary conservation from prokaryotes to eukaryotes. Dysregulation of TUFM has been associated with mitochondrial disorders. Although early hypothesis suggests that TUFM is localized within mitochondria, recent studies identify its presence in the cytoplasm, with this subcellular distribution being linked to distinct functions of TUFM. Significantly, in addition to its established function in mitochondrial protein quality control, recent research indicates a broader involvement of TUFM in the regulation of programmed cell death processes (e.g., autophagy, apoptosis, necroptosis, and pyroptosis) and its diverse roles in viral infection, cancer, and other disease conditions. This review seeks to offer a current summary of TUFM's biological functions and its complex regulatory mechanisms in human health and disease. Insight into these intricate pathways controlled by TUFM may lead to the potential development of targeted therapies for a range of human diseases.

Biological Insights and Radiation-Immuno-Oncology Developments in Primary and Secondary Brain Tumors

Malignant central nervous system (CNS) cancers include a group of heterogeneous dis-eases characterized by a relative resistance to treatments and distinguished as either primary tumors arising in the CNS or secondary tumors that spread from other organs into the brain. Despite therapeutic efforts, they often cause significant mortality and morbidity across all ages. Radiotherapy (RT) remains the main treatment for brain cancers, improving associated symptoms, improving tumor control, and inducing a cure in some. However, the ultimate goal of cancer treatment, to improve a patient's survival, remains elusive for many CNS cancers, especially primary tumors. Over the years, there have thus been many preclinical studies and clinical trials designed to identify and overcome mechanisms of resistance to improve outcomes after RT and other therapies. For example, immunotherapy delivered concurrent with RT, especially hypo-fractionated stereotactic RT, is synergistic and has revolutionized the clinical management and outcome of some brain tumors, in particular brain metastases (secondary brain tumors). However, its impact on gliomas, the most common primary malignant CNS tumors, remains limited. In this review, we provide an overview of radioresistance mechanisms, the emerging strategies to overcome radioresistance, the role of the tumor microenviroment (TME), and the selection of the most significant results of radiation-immuno-oncological investigations. We also identify novel therapeutic opportunities in primary and secondary brain tumors with the purpose of elucidating current knowledge and stimulating further research to improve tumor control and patients' survival.

Advances in Anti-Cancer Drug Development: Metformin as Anti-Angiogenic Supplemental Treatment for Glioblastoma

According to the WHO 2016 classification, glioblastoma is the most prevalent primary tumor in the adult central nervous system (CNS) and is categorized as grade IV. With an average lifespan of about 15 months from diagnosis, glioblastoma has a poor prognosis and presents a significant treatment challenge. Aberrant angiogenesis, which promotes tumor neovascularization and is a prospective target for molecular target treatment, is one of its unique and aggressive characteristics. Recently, the existence of glioma stem cells (GSCs) within the tumor, which are tolerant to chemotherapy and radiation, has been linked to the highly aggressive form of glioblastoma. Anti-angiogenic medications have not significantly improved overall survival (OS), despite various preclinical investigations and clinical trials demonstrating encouraging results. This suggests the need to discover new treatment options. Glioblastoma is one of the numerous cancers for which metformin, an anti-hyperglycemic medication belonging to the Biguanides family, is used as first-line therapy for type 2 diabetes mellitus (T2DM), and it has shown both in vitro and in vivo anti-tumoral activity. Based on these findings, the medication has been repurposed, which has shown the inhibition of many oncopromoter mechanisms and, as a result, identified the molecular pathways involved. Metformin inhibits cancer cell growth by blocking the LKB1/AMPK/mTOR/S6K1 pathway, leading to selective cell death in GSCs and inhibiting the proliferation of CD133+ cells. It has minimal impact on differentiated glioblastoma cells and normal human stem cells. The systematic retrieval of information was performed on PubMed. A total of 106 articles were found in a search on metformin for glioblastoma. Out of these six articles were Meta-analyses, Randomized Controlled Trials, clinical trials, and Systematic Reviews. The rest were Literature review articles. These articles were from the years 2011 to 2024. Appropriate studies were isolated, and important information from each of them was understood and entered into a database from which the information was used in this article. The clinical trials on metformin use in the treatment of glioblastoma were searched on clinicaltrials.gov. In this article, we examine and evaluate metformin's possible anti-tumoral effects on glioblastoma, determining whether or not it may appropriately function as an anti-angiogenic substance and be safely added to the treatment and management of glioblastoma patients.

A glutamatergic biomarker panel enables differentiating Grade 4 gliomas/astrocytomas from brain metastases

Background

The differentiation of high-grade glioma and brain tumors of an extracranial origin is eminent for the decision on subsequent treatment regimens. While in high-grade glioma, a surgical resection of the tumor mass is a fundamental part of current standard regimens, in brain metastasis, the burden of the primary tumor must be considered. However, without a cancer history, the differentiation remains challenging in the imaging. Hence, biopsies are common that may help to identify the tumor origin. An additional tool to support the differentiation may be of great help. For this purpose, we aimed to identify a biomarker panel based on the expression analysis of a small sample of tissue to support the pathological analysis of surgery resection specimens. Given that an aberrant glutamate signaling was identified to drive glioblastoma progression, we focused on glutamate receptors and key players of glutamate homeostasis.

Methods

Based on surgically resected samples from 55 brain tumors, the expression of ionotropic and metabotropic glutamate receptors and key players of glutamate homeostasis were analyzed by RT-PCR. Subsequently, a receiver operating characteristic (ROC) analysis was performed to identify genes whose expression levels may be associated with either glioblastoma or brain metastasis.

Results

Out of a total of 29 glutamatergic genes analyzed, nine genes presented a significantly different expression level between high-grade gliomas and brain metastases. Of those, seven were identified as potential biomarker candidates including genes encoding for AMPA receptors GRIA1, GRIA2, kainate receptors GRIK1 and GRIK4, metabotropic receptor GRM3, transaminase BCAT1 and the glutamine synthetase (encoded by GLUL). Overall, the biomarker panel achieved an accuracy of 88% (95% CI: 87.1, 90.8) in predicting the tumor entity. Gene expression data, however, could not discriminate between patients with seizures from those without.

Conclusion

We have identified a panel of seven genes whose expression may serve as a biomarker panel to discriminate glioblastomas and brain metastases at the molecular level. After further validation, our biomarker signatures could be of great use in the decision making on subsequent treatment regimens after diagnosis.