Glioma: molecular signature and crossroads with tumor microenvironment

Engineered nanovesicles targeting SERPINE1 overcome temozolomide resistance in glioblastoma

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with limited treatment options due to its resistance to temozolomide (TMZ). This study explores a novel therapeutic approach using engineered cell membrane nanovesicles loaded with SERPINE1 inhibitors to combat TMZ resistance. High-throughput sequencing identified pivotal genes associated with resistance, while the nanovesicles demonstrated excellent stability and the ability to cross the blood-brain barrier. Functional assays revealed significant suppression of GBM cell viability, migration, and invasion, accompanied by reduced expression of SERPINE1 and VEGF, suggesting inhibition of angiogenesis and tumor progression. These findings highlight the potential of SERPINE1-targeted nanovesicles as an innovative and effective strategy for overcoming TMZ resistance in GBM.

lncRNA BBOX1-AS1 regulates the miR-382-5p/CBX3 Signalling pathway to affect the proliferation and apoptosis of glioblastoma cells

OBJECTIVE

This study aims to investigate the role of long noncoding RNA (lncRNA) BBOX1-AS1 in regulating the miR-382-5p/CBX3 axis and its impact on glioblastoma cell proliferation and apoptosis.

METHODS

U-87 MG glioblastoma cells were divided into the following groups: control, si-NC, si-BBOX1-AS1, si-BBOX1-AS1 + inhibitor NC, si-BBOX1-AS1 + miR-382-5p inhibitor, miR-NC, miR-382-5p mimic, miR-382-5p mimic+pc-NC, and miR-382-5p mimic+pc-CBX3. The expression levels of lncRNAs BBOX1-AS1, miR-382-5p, and CBX3 were detected via qRT-PCR. Cell proliferation was assessed via MTT assays. Apoptosis rates and caspase 3 activity were measured via flow cytometry and caspase 3 activity assay kits. Western blotting was used to evaluate CBX3 protein expression. Dual-luciferase reporter assays were conducted to verify the relationship between the lncRNA BBOX1-AS1 and miR-382-5p. A similar assay was performed for miR-382-5p and CBX3.

RESULTS

Compared to normal human astrocytes (HA1800), glioblastoma cells (T98G, HS 683, U251, and U87 MG) exhibited higher levels of lncRNA BBOX1-AS1 and CBX3, along with lower levels of miR-382-5p (P < 0.05). Compared with the si-NC cells, the U-87 MG cells in the si-BBOX1-AS1 group presented reduced lncRNA BBOX1-AS1 expression, proliferation ability, and CBX3 protein expression but increased miR-382-5p levels, apoptosis rates, and Caspase 3 activity (P < 0.05). Compared with the si-BBOX1-AS1 + inhibitor NC group, the si-BBOX1-AS1 + miR-382-5p inhibitor group presented decreased miR-382-5p levels, apoptosis rates, and Caspase 3 activity but increased CBX3 protein expression and proliferation ability (P < 0.05). Compared with the control, the miR-382-5p mimic reduced CBX3 protein expression and proliferation ability while increasing the apoptosis rate and caspase 3 activity (P < 0.05). However, overexpression of CBX3 (miR-382-5p mimic+pc-CBX3) reversed the effects of the miR-382-5p mimic (P < 0.05). Dual-luciferase assays confirmed the relationships between lncRNA BBOX1-AS1 and miR-382-5p and between miR-382-5p and CBX3 (P < 0.05).

CONCLUSION

Knockdown of lncRNA BBOX1-AS1 inhibits U-87 MG cell proliferation and promotes apoptosis by upregulating miR-382-5p and downregulating CBX3 expression.

The JAK1/STAT3 pathway mediates the effects of SERPINH1 on glioma EMT

Glioma is marked by swift cell proliferation, extensive invasion and poor outcomes. Serine protease inhibitor H1 (SERPINH1) encoding heat shock protein 47, a collagen-specific molecular chaperone, plays a role in a number of cancers. However, its definite role in glioma remains unclear. The aim of the present study was to investigate the role of SERPINH1 in glioma progression, especially its impact on cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT). The glioma cell lines LN229, T98, U251 and U87MG were transfected with lentivirus for stable knockdown or overexpression of SERPINH1. Assays assessing cell proliferation, migration and invasion were conducted to investigate the role of SERPINH1 in these processes. Bioinformatic analysis was conducted using The Cancer Genome Atlas and the Chinese Glioma Genome Atlas databases to identify potential molecular pathways associated with SERPINH1. Western blotting (WB) was employed to examine the expression of significant proteins in the JAK1/STAT3 signaling pathway and EMT markers. Nude mice were used for in vivo experiments to evaluate tumor growth and changes related to EMT. Overexpression of SERPINH1 notably increased glioma cell proliferation, migration and invasion, whereas knockdown suppressed these activities. Bioinformatic analyses revealed that SERPINH1 is closely associated with the JAK1/STAT3 signaling pathway and EMT-related genes. WB results confirmed that SERPINH1 regulates the activation of JAK1/STAT3 and influences the levels of EMT markers such as N- and E-cadherin. The JAK1/STAT3 agonist RO8191 partially rescued glioma cell behavior in the SERPINH1 knockdown group, while the inhibitor STATTIC partially weakened the enhanced effects in the SERPINH1 overexpression group. In vivo, SERPINH1 overexpression accelerated tumor growth and EMT progression, while knockdown resulted in a reduction in tumor size and the expression of EMT markers. SERPINH1 is essential for glioma progression, enhancing cell proliferation, migration, invasion and EMT by activating the JAK1/STAT3 signaling pathway. These results indicate that targeting SERPINH1 could provide a promising new approach for glioma therapy.

Charged dendrimers reduce glioblastoma viability by modulating lysosomal activity and HMGB1-RAGE interaction

Dendrimers and dendrimer-based self-assembly systems have emerged as promising nanocarriers for a variety of applications, including anti-cancer therapies, modulation of the tumor microenvironment, and imaging. Here, we explored the therapeutic potential of two charged dendrimers, dendritic polyglycerol sulfate (dPGS) and dendritic polyglycerol amine (dPGA), in the context of glioblastoma multiforme (GBM). Docosahexaenoic acid (DHA) has shown potential in GBM. We therefore examined dPGS and dPGA effects alone and in combination with DHA. Using 2D cell models and 3D tumoroids, we showed that DHA with dPGA reduced tumor integrity and cell viability. dPGS reduced oxidative stress, whereas dPGA reduced lysosomal acidification, contributing to cellular dysfunction. Both dendrimers influence the interaction between high mobility group box 1 (HMGB1) and the receptor for advanced glycation end products (RAGE). The surfaces of the HMGB1-RAGE complex provide binding sites for interactions of charged molecules like dPGS and dPGA, suggesting the contribution of these interactions to cytotoxicity. In summary, our findings show that combining DHA with charged dendrimers (dPGS and dPGA) enhances GBM cytotoxicity through several mechanisms, involving lysosomal alkalinization, lipid peroxidation and modulation of the HMGB1-RAGE complex.

Therapeutic efficacy of TMTP1-modified EVs in overcoming bone metastasis and immune resistance in PIK3CA mutant NSCLC

Non-small cell lung cancer (NSCLC) with PIK3CA mutations demonstrates significant challenges in treatment due to enhanced bone metastasis and immune checkpoint resistance. This study investigates the efficacy of tumor-targeting peptide 1-modified cancer stem cell-derived extracellular vesicles (TMTP1-TSRP-EVs) in reshaping the tumor microenvironment and reversing immune checkpoint resistance in NSCLC. By integrating TMTP1-TSRP into EVs, we aim to specifically deliver therapeutic agents to NSCLC cells, focusing on inhibiting the PI3K/Akt/mTOR pathway, a crucial driver of oncogenic activity and immune evasion in PIK3CA-mutated cells. Our comprehensive in vitro and in vivo analyses show that TMTP1-TSRP-EVs significantly inhibit tumor growth, reduce PD-L1 expression, and enhance CD8+ T cell infiltration, effectively reversing the immune-suppressive microenvironment. Moreover, the in vivo models confirm that our approach not only suppresses bone metastases but also overcomes primary resistance to immune checkpoint inhibitors by modulating the expression of key immunological markers. These findings suggest that targeted delivery of TMTP1-TSRP-EVs could provide a novel therapeutic strategy for treating PIK3CA-mutant NSCLC, offering significant improvements over traditional therapies by directly targeting the molecular pathogenesis of tumor resistance and metastasis. Molecular Mechanisms Reshaping the TME to Halt PI3K-Mutant Bone Metastasis of NSCLC and Overcoming Primary ICI Resistance. (Created by BioRender).

Single-cell RNA sequencing for characterizing the immune communication and iron metabolism roles in CD31+ glioma cells

Background

Gliomas are aggressive brain tumors marked by complex cellular interactions and significant immune cell infiltration. This study investigated the role of CD31+ immune cells, specifically macrophages and T cells, in the glioma microenvironment through single-cell RNA sequencing (scRNA-seq).

Methods

We employed the CellChat framework to map cell-cell communication pathways and used Monocle3 for pseudotime trajectory analysis to characterize the signaling and developmental progressions within CD31+ cells. Pathways such as osteopontin (SPP1) and major histocompatibility complex class II (MHC-II) were analyzed in terms of their role in immune regulation, and we examined the expression of ferritin, an iron-binding protein, to assess its potential function in modulating CD31+ cell activity.

Results

Our findings highlight the expression of key pathways, including SPP1 and MHC-II, influencing immune regulation. Ferritin was found to be highly expressed in CD31+ cells, suggesting a dual role in iron metabolism and immune modulation within the glioma microenvironment.

Conclusions

This study clarified the distinct roles of CD31+ immune cells in glioma progression and identified ferritin as a potential therapeutic target for modulating immune responses in gliomas. These findings may offer new directions in glioma research and the development of immunotherapy, which can aid in improving treatment outcomes.

Fn14-targeting, NIR-II responsive nanomaterials for enhanced radiotherapy against glioblastomas

Radiotherapy is a common treatment option for patients with glioblastoma multiforme. However, tumor heterogeneity causes varying responses to radiation among different tumor subpopulations. Cancer cells that endure radiotherapy exhibit radioresistance, resulting in the ineffectiveness of radiation therapy and eventual tumor relapse. In this study, we discovered that the fibroblast growth factor-inducible 14 (Fn14)-positive tumor cells were enriched in tumor residual foci after radiation, ultimately leading to treatment failure. Fn14-expressing glioma cells survived ionizing radiation through preferential activation of DNA damage checkpoint response. We have thus engineered an Fn14-targeting and NIR-II responsive plasmonic gold nanosystem named Fn14-AuNPs, which can precisely internalize into Fn14-overexpressed glioma cells and have an excellent BBB-crossing capability. As gold nanoparticles, by inhibition of DNA repair processes and induction of G2/M cells cycle arrest, Fn14-AuNPs nanoparticles improved the radiosensitivity of tumor cells. Meanwhile, Fn14-AuNPs induced localized heat under NIR-II photoirradiation, thus impeding RT-induced DNA damage checkpoint response. This versatile nanosensitizer, combined with NIR-II laser photoirradiation, can eradicate radioresistant subpopulations of glioblastoma and improve the therapeutic effect of radiotherapy. This finding presents an effective radiosensitization strategy by targeting radioresistant subpopulations, which can efficiently overcome the constraints imposed in clinical radiotherapy and offer a hopeful avenue to enhance the treatment effectivity of radiotherapy in glioblastoma.

Immune response recalibration using immune therapy and biomimetic nano-therapy against high-grade gliomas and brain metastases

Although with aggressive standards of care like surgical resection, chemotherapy, and radiation, high-grade gliomas (HGGs) and brain metastases (BM) treatment has remained challenging for more than two decades. However, technological advances in this field and immunotherapeutic strategies have revolutionized the treatment of HGGs and BM. Immunotherapies like immune checkpoint inhibitors, CAR-T targeting, oncolytic virus-based therapy, bispecific antibody treatment, and vaccination approaches, etc., are emerging as promising avenues offering new hope in refining patient's survival benefits. However, selective trafficking across the blood-brain barrier (BBB), immunosuppressive tumor microenvironment (TME), metabolic alteration, and tumor heterogeneity limit the therapeutic efficacy of immunotherapy for HGGs and BM. Furthermore, to address this concern, the NanoBioTechnology-based bioinspired delivery system has been gaining tremendous attention in recent years. With technological advances such as Trojan horse targeting and infusing/camouflaging nanoparticles surface with biological molecules/cells like immunocytes, erythrocytes, platelets, glioma cell lysate and/or integrating these strategies to get hybrid membrane for homotypic recognition. These biomimetic nanotherapy offers advantages over conventional nanoparticles, focusing on greater target specificity, increased circulation stability, higher active loading capacity, BBB permeability (inherent inflammatory chemotaxis of neutrophils), decreased immunogenicity, efficient metabolism-based combinatorial effects, and prevention of tumor recurrence by induction of immunological memory, etc. provide new age of improved immunotherapies outcomes against HGGs and BM. In this review, we emphasize on neuro-immunotherapy and the versatility of these biomimetic nano-delivery strategies for precise targeting of hard-to-treat and most lethal HGGs and BM. Moreover, the challenges impeding the clinical translatability of these approaches were addressed to unmet medical needs of brain cancers.

Clusterin-mediated polarization of M2 macrophages: a mechanism of temozolomide resistance in glioblastoma stem cells

Glioblastoma remains one of the most lethal malignancies, largely due to its resistance to standard chemotherapy such as temozolomide. This study investigates a novel resistance mechanism involving glioblastoma stem cells (GSCs) and the polarization of M2-type macrophages, mediated by the extracellular vesicle (EV)-based transfer of Clusterin. Using 6-week-old male CD34+ humanized huHSC-(M-NSG) mice (NM-NSG-017) and glioblastoma cell lines (T98G and U251), we demonstrated that GSC-derived EVs enriched with Clusterin induce M2 macrophage polarization, thereby enhancing temozolomide resistance in glioblastoma cells. Single-cell and transcriptome sequencing revealed close interactions between GSCs and M2 macrophages, highlighting Clusterin as a key mediator. Our findings indicate that Clusterin-rich EVs from GSCs drive glioblastoma cell proliferation and resistance to temozolomide by modulating macrophage phenotypes. Targeting this pathway could potentially reverse resistance mechanisms, offering a promising therapeutic approach for glioblastoma. This study not only sheds light on a critical pathway underpinning glioblastoma resistance but also lays the groundwork for developing therapies targeting the tumor microenvironment. Our results suggest a paradigm shift in understanding glioblastoma resistance, emphasizing the therapeutic potential of disrupting EV-mediated communication in the tumor microenvironment.

Identification of distinct profiles of glioblastoma through the immunocapture of extracellular vesicles from patient plasma

Glioblastoma (GBM), a primary brain tumor, exhibits intratumoral heterogeneity and dynamic spatial-temporal changes. GBM-derived extracellular vesicles (EVs), reflecting tumor characteristics, present potential as liquid-biopsy markers for early diagnosis and monitoring. This study aims to evaluate molecular signatures of plasma-derived EVs from GBM patients using a conventional flow cytometer. EVs have been isolated from glioma patients and healthy controls (HCs) plasma using density gradient ultracentrifugation (DGU). EVs were evaluated by bead-based multiplex analysis in a conventional flow cytometer. Principal component analysis (PCA), hierarchical clustering, and correlation analysis provided comprehensive insights into EV characteristics. EVs successfully isolated were visualized in transmission and scanning electron microscopy (STEM). Bead-based multiplex analysis in flow cytometer detected the level of 37 EV surface markers, including tumor-related, cancer stem cell, endothelial cell, and immune cell- specific antigens. PCA identified the EV surface markers that are most significant for differentiating the subjects, and hierarchical clustering revealed four distinct clusters based on EV surface marker levels. EV molecular signature demonstrated considerable heterogeneity across patient clusters. The presence of CD29 emerged not only as a defining factor for a cluster of patients, but also served as a marker to differentiate patients from HCs.

Tumor microenvironment: recent advances in understanding and its role in modulating cancer therapies

Tumor microenvironment (TME) denotes the non-cancerous cells and components presented in the tumor, including molecules produced and released by them. Interactions between cancer cells, immune cells, stromal cells, and the extracellular matrix within the TME create a dynamic ecosystem that can either promote or hinder tumor growth and spread. The TME plays a pivotal role in either promoting or inhibiting tumor growth and dissemination, making it a critical factor to consider in the development of effective cancer therapies. Understanding the intricate interplay within the TME is crucial for devising effective cancer therapies. Combination therapies involving inhibitors of immune checkpoint blockade (ICB), and/or chemotherapy now offer new approaches for cancer therapy. However, it remains uncertain how to best utilize these strategies in the context of the complex tumor microenvironment. Oncogene-driven changes in tumor cell metabolism can impact the TME to limit immune responses and present barriers to cancer therapy. Cellular and acellular components in tumor microenvironment can reprogram tumor initiation, growth, invasion, metastasis, and response to therapies. Components in the TME can reprogram tumor behavior and influence responses to treatments, facilitating immune evasion, nutrient deprivation, and therapeutic resistance. Moreover, the TME can influence angiogenesis, promoting the formation of blood vessels that sustain tumor growth. Notably, the TME facilitates immune evasion, establishes a nutrient-deprived milieu, and induces therapeutic resistance, hindering treatment efficacy. A paradigm shift from a cancer-centric model to a TME-centric one has revolutionized cancer research and treatment. However, effectively targeting specific cells or pathways within the TME remains a challenge, as the complexity of the TME poses hurdles in designing precise and effective therapies. This review highlights challenges in targeting the tumor microenvironment to achieve therapeutic efficacy; explore new approaches and technologies to better decipher the tumor microenvironment; and discuss strategies to intervene in the tumor microenvironment and maximize therapeutic benefits.

Cross-Talk Between Cancer and Its Cellular Environment-A Role in Cancer Progression

The tumor microenvironment is a dynamic and complex three-dimensional network comprising the extracellular matrix and diverse non-cancerous cells, including fibroblasts, adipocytes, endothelial cells and various immune cells (lymphocytes T and B, NK cells, dendritic cells, monocytes/macrophages, myeloid-derived suppressor cells, and innate lymphoid cells). A constantly and rapidly growing number of studies highlight the critical role of these cells in shaping cancer survival, metastatic potential and therapy resistance. This review provides a synthesis of current knowledge on the modulating role of the cellular microenvironment in cancer progression and response to treatment.

Matrix Stiffness Regulates Interleukin-10 Secretion in Human Microglia (HMC3) via YAP-Mediated Mechanotransduction

Microglia, as resident immune cells in the brain, adhere to the extracellular matrix and typically exhibit anti-inflammatory polarization under normal physiological conditions. Despite their pivotal roles, the regulatory effects of extracellular matrix properties on microglial function and the associated molecular mechanisms remain inadequately understood. Here, we elucidate how matrix stiffness modulates interleukin-10 (IL-10) secretion in human microglia (HMC3) via yes-associated protein (YAP)-mediated mechanotransduction. Using soft collagen Ⅰ-coated hydrogels, we observed a substantial reduction in IL-10 secretion, accompanied by a decrease in the expression and nuclear localization of YAP compared to cells adhered to glass substrates. With increasing hydrogel substrate stiffness, the expression and nuclear localization of YAP were enhanced, leading to an elevated secretion of IL-10. Subsequently, to further investigate the relationship between YAP and IL-10, we performed YAP depletion experiments, which revealed that nuclear exclusion of YAP suppressed IL-10 secretion. Interestingly, overexpression of YAP in microglia did not markedly affect IL-10 levels. We seeded YAP-knockdown microglia onto hydrogels of varying stiffness, and no significant differences were observed in IL-10 secretion. Our findings suggested that cytoskeletal polymerization was crucial for the regulation of IL-10 secretion mediated by YAP. Given the crucial role of IL-10 in the tumor microenvironment, we further found shYAP-microglia attenuated the pro-proliferative effect of microglia on gliomas. Besides, when YAP was silenced, actin of human microglia decreased, and their contractility was weakened. In summary, this study identifies YAP as a pivotal molecule in controlling cytokine secretion and sensing matrix stiffness in microglia. These insights offer potential therapeutic avenues for glioma treatment by targeting YAP-mediated pathways in microglial cells.

Integrated Analysis to Reveal Heterogeneity of Tumor-Associated Neutrophils in Glioma

BACKGROUND

Glioma, characterized by its cellular and molecular heterogeneity, presents formidable challenges in treatment strategy and prognostic assessment. The tumor microenvironment (TME) profoundly influences tumor behavior and treatment response, with tumor-associated neutrophils (TANs) playing a complex but understudied role. This study aimed to investigate the heterogeneity and role of TANs in glioma and to develop a prognostic model.

METHODS

Analysis of scRNA-seq data identified cellular subpopulations and differentially expressed neutrophil-related genes (DE-NRGs). Bulk RNA-seq was obtained from four independent datasets. Molecular subtypes of glioma samples were determined by consensus clustering. WGCNA was conducted to elucidate the association between gene modules and subtypes. We developed a risk score model. Expression of selected genes was confirmed using immunohistochemistry (IHC). In vitro experiments were also performed for functional verification, including CCK8, EdU, Transwell, and TUNEL assays.

RESULTS

A total of 108 DE-NRGs for TANs were identified based on scRNA-seq data. Two molecular subtypes were characterized, showing significant differences in prognosis and clinical features. Immune-related analyses demonstrated varied immunological characteristics between subtypes. The risk score model was constructed with 7 genes, including AEBP1, CAVIN1, DCTD, DEPP1, DUSP6, FKBP9, and UGCG. It showed significant prognostic value and was validated across three external datasets. The mutation landscape highlighted higher IDH mutation prevalence in low-risk groups. Drug sensitivity analysis indicated TMZ resistance in high-risk groups. In vitro experiments showed that UGCG could promote glioma cell proliferation, migration, and invasion, while decreasing apoptosis.

CONCLUSION

This study explored the heterogeneity of TANs and developed a prognostic model, providing insights for prognostic prediction and guiding personalized treatment strategies in glioma. Declaration of Generative AI in Scientific Writing: The authors declare nonuse of generative AI and AI-assisted technologies in the writing process.

The research progress on meningeal metastasis in solid tumors

Meningeal metastasis (MM), particularly Leptomeningeal metastases (LM), represents the advanced stage of solid tumors and poses a significant threat to patients' lives. Moreover, it imposes a substantial burden on society. LM represents the ultimate and most fatal stage of solid tumors, inflicting devastating consequences on patients and imposing a substantial burden on society. The incidence of LM continues to rise annually, emphasizing the urgent need for early recognition and treatment initiation in individuals with LM to significantly extend overall patient survival. Despite rapid advancements in current LM detection and treatment methods, the diagnosis of LM remains constrained by several limitations such as low diagnostic efficiency, the therapeutic outcomes remain suboptimal. Furthermore, there is currently no universally recognized industry standard for LM treatment, further underscoring its status as an unresolved challenge in tumor management. Additionally, progress towards elucidating the mechanisms underlying MM has stagnated. Therefore, this review aims to comprehensively summarize recent research advances pertaining to MM in solid tumors by elucidating its underlying mechanisms, exploring diagnostic and prognostic biomarkers while addressing existing research challenges.

EFNB1 drives glioma progression and shapes the immune microenvironment: a potential prognostic biomarker

Gliomas, a heterogeneous group of tumors affecting the brain and spinal cord, present a significant clinical challenge. Ephrin B1 (EFNB1) has been implicated in various malignancies. However, its role in gliomas remained poorly understood. Hence, this study aimed to elucidate the connection between EFNB1 and the progression of glioma. A retrospective RNA-seq analysis was conducted by utilizing the data from glioma patients in the TCGA and CGGA databases. Kaplan-Meier survival analysis and multivariate regression models were employed to evaluate the prognostic significance of EFNB1. RT-PCR was used to quantify EFNB1 expression in glioma tissues and cell lines. Meanwhile, in vitro assays were carried out to assess its functional roles in glioma cells. Our findings demonstrated that EFNB1 expression was significantly elevated in gliomas and other cancers. Moreover, high EFNB1 expression was closely correlated with advanced clinical stages and poor prognosis. Notably, multivariate analysis identified EFNB1 as an independent prognostic factor for overall survival. KEGG pathway analysis suggested that EFNB1 was involved in critical biological processes, including the cell cycle, protein processing in the endoplasmic reticulum, Epstein-Barr virus infection, and Salmonella infection. Furthermore, EFNB1 expression was associated with immune cell infiltration, particularly Th2 cells, macrophages, and plasmacytoid dendritic cells. In glioma cells, EFNB1 expression was markedly increased. Consequently, functional experiments demonstrated that EFNB1 knockdown inhibited glioma cell proliferation, invasion, and migration. These results highlighted EFNB1 as a novel independent prognostic biomarker and suggest its potential role in shaping the immunological microenvironment of gliomas.

METTL3/YTDHF1 Stabilizes MTCH2 mRNA to Regulate Ferroptosis in Glioma Cells

BACKGROUND

Gliomas are aggressive brain tumors known for their poor prognosis and resistance to standard treatment options. Ferroptosis is an iron-dependent form of regulated cell death that has emerged as a promising target for cancer treatment. This study examined how the methyltransferase-like 3/YTH domain family protein 1 (METTL3/YTHDF1) axis influences ferroptosis and glioma progression by stabilizing mitochondrial carrier homolog 2 (MTCH2) messenger RNA (mRNA).

METHODS

MTCH2 expression in glioma tissues and cell lines was evaluated through quantitative real-time polymerase chain reaction (PCR) and western blot analyses. To assess the effects of MTCH2 knockdown and overexpression on glioma cell functions, we performed a series of functional assays, including cell viability, colony formation, and measurements of lipid reactive oxygen species (lipid ROS) and malondialdehyde (MDA) levels. Additionally, we conducted RNA immunoprecipitation (RIP) and RNA stability assays to explore the underlying mechanisms governing the interaction between METTL3, YTHDF1, and the stability of MTCH2 mRNA.

RESULTS

MTCH2 was significantly upregulated in glioma tissues and cell lines. Silencing of MTCH2 resulted in decreased glioma cell proliferation and induced ferroptosis, as evidenced by increased lipid peroxidation and ROS accumulation. Conversely, overexpression of MTCH2 enhanced glioma cell survival and reduced ferroptosis. METTL3-mediated N6-methyladenosine (m6A) modification enhanced MTCH2 mRNA stability by enabling YTHDF1 to bind and protect the modified mRNA from degradation.

CONCLUSION

The METTL3/YTHDF1/MTCH2 axis plays a critical role in glioma progression by inhibiting ferroptosis and promoting tumor cell survival. Targeting this pathway may provide a new and effective treatment strategy for glioma patients.

Ketogenic diet induces an inflammatory reactive astrocytes phenotype reducing glioma growth

The use of a ketogenic diet (KD) in glioma is currently tested as an adjuvant treatment in standard chemotherapy regimens. The metabolic shift induced by the KD leads to the generation of ketone bodies that can influence glioma cells and the surrounding microenvironment, but the mechanisms have not yet been fully elucidated. Here, we investigated the potential involvement of glial cells as mediators of the KD-induced effects on tumor growth and survival rate in glioma-bearing mice. Specifically, we describe that exposing glioma-bearing mice to a KD or to β-hydroxybutyrate (β-HB), one of the main KD metabolic products, reduced glioma growth in vivo, induced a pro-inflammatory phenotype in astrocytes and increased functional glutamate transporters. Moreover, we described increased intracellular basal Ca2+ levels in GL261 glioma cells treated with β-HB or co-cultured with astrocytes. These data suggest that pro-inflammatory astrocytes triggered by β-HB can be beneficial in counteracting glioma proliferation and neuronal excitotoxicity, thus protecting brain parenchyma.

Research trends in glioma chemoradiotherapy resistance: a bibliometric analysis (2003-2023)

Background

Glioma is the most aggressive primary malignant tumor of the central nervous system, characterized by high recurrence rates and resistance to chemoradiotherapy, making therapeutic resistance a major challenge in neuro-oncology. Recent research emphasizes the role of the tumor microenvironment (TME) and immune modulation in glioma progression and resistance. Despite these advances, a comprehensive bibliometric analysis of research trends in glioma chemoradiotherapy resistance over the past two decades is lacking. This study aims to systematically evaluate the research landscape, identify emerging hotspots, and provide guidance for future investigations.

Methods

Articles on glioma chemoradiotherapy resistance published between 2003 and 2023 were retrieved from the Web of Science Core Collection, resulting in 4,528 publications. Bibliometric tools, including VOSviewer, CiteSpace, and R packages such as bibliometrix and ggplot2, were used to analyze co-authorship networks, keyword evolution, and citation bursts to identify collaboration patterns, thematic developments, and influential contributions.

Results

Publication output increased significantly between 2013 and 2022, peaking at 650 articles in 2022. Over 1,000 institutions from 88 countries contributed to this research. The United States, Switzerland, and Germany showed the highest citation impact, while China led in publication volume but demonstrated relatively lower citation influence. The research focus has shifted from traditional topics such as the "MGMT gene" to emerging areas including the "tumor microenvironment," "immune infiltration," and "nanoparticles." The androgen receptor was identified as a promising but underexplored therapeutic target.

Conclusions

Research on glioma chemoradiotherapy resistance has seen substantial growth, with increasing emphasis on immune modulation, the tumor microenvironment, and novel therapeutic targets such as the androgen receptor. This study represents the first comprehensive bibliometric analysis of this field, providing a detailed overview of research trends and potential directions for future studies. The findings highlight the need for strengthened international collaboration and multidisciplinary approaches to address the challenges of therapeutic resistance in glioma.

Circadian rhythm related genes signature in glioma for drug resistance prediction: a comprehensive analysis integrating transcriptomics and machine learning

BACKGROUND

Gliomas, 24% of all primary brain tumors, have diverse histology and poor survival rates, with about 70% recurring due to acquired or de novo resistance. Insomnia in patients is correlated strongly with circadian rhythm disruptions. The correlation between circadian rhythm disorders and drug resistance of some tumors has been proved. However, the precise mechanism underlying the relationship between glioma and circadian rhythm disorders has not been elucidated.

METHODS

Circadian rhythm-related genes (CRRGs) were identified using the least absolute shrinkage and selection operator (LASSO) regression, and stochastic gradient descent (SGD) was performed to form a circadian rhythm-related score (CRRS) model. The studies of immune cell infiltration, genetic variations, differential gene expression pattern, and single cell analysis were performed for exploring the mechanisms of chemotherapy resistance in glioma. The relationship between CRRGs and chemosensitivity was also confirmed by IC 50 (half maximal inhibitory concentration) analysis.

RESULT

Signatures of 16 CRRGs were screened out and identified. Based on the CRRS model, an optimal comprehensive nomogram was created, exhibiting a favorable potential for predicting drug resistance in samples. Immune infiltration, cell-cell communication, and single cell analysis all indicated that high CRRS group was closely related to innate immune cells. IC50 analysis showed that CRRG knockdown enhanced the chemosensitivity of glioma.

CONCLUSION

A significant correlation between CRRGs, drug resistance of glioma, and innate immune cells was found, which might hold a significant role in the drug resistance of glioma.

Natural Source of Drugs Targeting Central Nervous System Tumors-Focus on NAD(P)H Oxidoreductase 1 (NQO1) Activity

Central nervous system (CNS) tumors involve a large and diverse group of malignancies that arise from various cell types within the brain tissue. Although there are advances in treatments, CNS tumors still remain challenging, due to their complex biology and the delicate nature of the surrounding tissue. NAD(P)H O=oxidoreductase 1 (NQO1) is an enzyme that plays a critical role in the detoxification of quinones, protecting cells from oxidative stress. In CNS tumors this enzyme is often overexpressed, which contributes to the resistance of tumor cells to chemotherapy by enhancing their antioxidant defenses. NQO1 influences the progression of CNS tumors by affecting downstream signaling pathways, such as those involving the transcription factor SNAIL, as well as others that are associated with tumor behavior. Plants represent a valuable source of numerous constituents with different chemical structures known to affect different molecular signaling pathways associated with different pathologies.

PLIN1 suppresses glioma progression through regulating lipid metabolism

Glioma is a common and destructive brain tumor, which is highly heterogeneous with poor prognosis. Developing diagnostic and prognostic markers to identify and treat glioma early would significantly improve the therapeutic outcomes. Here, we conducted RNA next-generation sequencing with 33 glioma samples and 15 normal brain samples. We found Perilipin 1 (PLIN1) downregulated in glioma and correlated with poorer outcome. Subsequent experiments revealed that up regulation of PLIN1 led to repressed cell growth and invasion in glioma. Moreover, overexpression of PLIN1 increased lipid accumulation in glioma cells, with increasing expression of lipid biosynthesis related genes and decreasing expression of lipolysis related genes. Mechanically, we revealed that the PI3K/AKT axis could regulate PLIN1 levels in glioma, that inhibition of the activity of PI3K/AKT axis could increase PLIN1 levels in glioma. In conclusion, the dysregulation PI3K/AKT axis led to PLIN1 downregulation and the following tumor proliferation, invasion and lipid metabolism reprogramming in glioma.

Decoding the Role of Kinesin Superfamily Proteins in Glioma Progression

Glioma is a highly aggressive and invasive brain tumor with limited treatment options, highlighting the need for novel therapeutic approaches. Kinesin superfamily proteins (KIFs) are a diverse group of motor proteins that play essential roles in cellular processes such as mitosis, intracellular transport, and signal transduction, all of which are crucial for tumorigenesis. This review focuses on the multifaceted role of KIFs in glioma, examining their clinical relevance, contribution to tumor progression, and potential as therapeutic targets. We discuss how KIFs influence key aspects of glioma biology, including cell proliferation, invasion, migration, and metastasis. Furthermore, we explore the regulation of the cell cycle and critical signaling pathways associated with glioma, such as PI3K-Akt, Wnt/β-catenin, and Hedgehog signaling by KIFs. The review also addresses the emerging interplay between KIFs and non-coding RNAs, including circular RNAs (circRNAs) and microRNAs (miRNAs), in glioma progression. Finally, we examine current therapeutic strategies targeting KIFs, including immunotherapy, chemotherapy, and small-molecule inhibitors, and their potential to improve treatment outcomes for glioma patients. By synthesizing these insights, this review underscores the significance of KIFs in glioma pathogenesis and their promise as novel therapeutic targets in the fight against glioma.

Emerging Approaches in Glioblastoma Treatment: Modulating the Extracellular Matrix Through Nanotechnology

Glioblastoma's (GB) complex tumor microenvironment (TME) promotes its progression and resistance to therapy. A critical component of TME is the extracellular matrix (ECM), which plays a pivotal role in promoting the tumor's invasive behavior and aggressiveness. Nanotechnology holds significant promise for GB treatment, with the potential to address challenges posed by both the blood-brain barrier and the GB ECM. By enabling targeted delivery of therapeutic and diagnostic agents, nanotechnology offers the prospect of improving treatment efficacy and diagnostic accuracy at the tumor site. This review provides a comprehensive exploration of GB, including its epidemiology, classification, and current treatment strategies, alongside the intricacies of its TME. It highlights nanotechnology-based strategies, focusing on nanoparticle formulations such as liposomes, polymeric nanoparticles, and gold nanoparticles, which have shown promise in GB therapy. Furthermore, it explores how different emerging nanotechnology strategies modulate the ECM to overcome the challenges posed by its high density, which restricts drug distribution within GB tumors. By emphasizing the intersection of nanotechnology and GB ECM, this review underscores an innovative approach to advancing GB treatment. It addresses the limitations of current therapies, identifies new research avenues, and emphasizes the potential of nanotechnology to improve patient outcomes.

ITGB4/GNB5 axis promotes M2 macrophage reprogramming in NSCLC metastasis

OBJECTIVE

Metastasis of non-small cell lung cancer (NSCLC) is a leading cause of high mortality. In recent years, the role of M2 macrophages in promoting tumor metastasis within the tumor microenvironment has garnered increasing attention. This study aims to investigate the role and potential mechanisms of the ITGB4/GNB5 axis in regulating M2 macrophage reprogramming and influencing NSCLC metastasis.

METHODS

This study first used single-cell sequencing technology to reveal the diverse subpopulation structure of NSCLC tumor tissues. Data analysis then identified the correlation between M2 macrophages and the malignant phenotype of NSCLC. Flow cytometry and immunohistochemistry were used to detect changes in M2 macrophages in NSCLC tissues. The impact of the ITGB4/GNB5 axis on M2 macrophage function was assessed through RNA sequencing and proteomic analysis. Finally, in vitro cell experiments and in vivo mouse models were used to validate the function and regulatory mechanisms of this axis.

RESULTS

Our study found diverse cellular subpopulations in NSCLC tumor tissues, with M2 macrophages closely associated with the malignant phenotype of NSCLC. We identified ITGB4 as a characteristic gene of NSCLC and predicted GNB5 as an interacting gene through database analysis. Activation of the ITGB4/GNB5 axis was shown to enhance M2 macrophage polarization, promoting their accumulation in the tumor microenvironment. This change further facilitated NSCLC invasion and metastasis by modulating related cytokines and signaling pathways. Animal experiments demonstrated that inhibition of the ITGB4/GNB5 axis significantly reduced tumor growth and metastasis.

CONCLUSION

The ITGB4/GNB5 axis reshapes the TME by promoting M2 macrophage polarization and functional enhancement, thereby facilitating tumor invasion and metastasis in NSCLC. This research provides new insights into the molecular mechanisms of NSCLC and offers potential molecular targets for future targeted therapies.

Development and experimental validation of dephosphorylation-related biomarkers to assess prognosis and immunotherapeutic response in gliomas

Background

Gliomas are common aggressive brain tumors with poor prognosis. Dephosphorylation-related biomarkers are in a void in gliomas. This study aims to construct a validated prognostic risk model for dephosphorylation, which will provide new directions for clinical treatment, prognostic assessment, and temozolomide (TMZ) resistance in glioma patients.

Methods

Screening dephosphorylation-related genes (DRGs) and transcriptome expression data from The Cancer Genome Atlas (TCGA), Molecular signatures database (MSigDB) and constructing risk scoring models. Kaplan-Meier (K-M), nomogram and ROC curve were used to assess the predictive efficacy of the model. Gene set enrichment analysis (GSEA), immune cell infiltration, immunotherapy response and chemotherapeutic drug sensitivity analysis were performed in this study. The correlation between chemotherapeutic drugs and the half maximal inhibitory concentration (IC50) values of 12 DRGs was analyzed. Cell division cycle 25A (CDC25A) and TMZ were screened and verified by experiments. Quantitative Real-Time PCR (qRT-PCR) detection of mRNA expression of 12 genes in human normal glial cells and two glioma cell lines. Transfection techniques overexpressed and knocked down CDC25A. qRT-PCR and Western Blot (WB) were used to detect the mRNA and protein expression levels of CDC25A. Subsequently, verify the effect of CDC25A on TMZ resistance in glioma cells.

Results

The model established in this study was able to accurately predict the prognosis of glioma patients. Besides, there were significant differences in GSEA, immune cell infiltration, immunotherapeutic response and chemotherapeutic drug sensitivity analysis between glioma patients in the high and low risk groups. The results of CCK8 experiments showed that overexpression of CDC25A increased the susceptibility of U251 and LN229 cells to TMZ, and knockdown of CDC25A attenuated the susceptibility of U251 and LN229 cells to TMZ.

Identification of cancer-associated fibroblast subtypes and prognostic model development in breast cancer: role of the RUNX1/SDC1 axis in promoting invasion and metastasis

In this study, we identified cancer-associated fibroblast (CAF) molecular subtypes and developed a CAF-based prognostic model for breast cancer (BRCA). The heterogeneity of cancer-associated fibroblasts (CAFs) and their significant involvement in the advancement of BRCA were discovered employing single-cell RNA sequencing. Notably, we discovered that the RUNX1/SDC1 axis enhances BRCA cell invasion and metastasis. RUNX1 transcriptionally upregulates SDC1, which facilitates extracellular matrix remodeling and promotes tumor cell migration. This finding highlights the vital contribution of CAFs to the tumor microenvironment and provides new potential targets for therapeutic intervention. The predictive model showcased remarkable precision in anticipating patient outcomes and could guide personalized treatment strategies.

Crosstalk between CD180-overexpression macrophages and glioma cells worsens patient survival through malignant phenotype promotion and immunosuppressive regulation

BACKGROUND

Understanding the molecular mechanisms in immunosuppressive regulation is crucial for improving immunotherapeutic strategies. Macrophages, the major immune cells in tumor microenvironment (TME), play a dual role in tumor progression. CD180, primarily expressed in macrophages, remains unclear and requires further investigation.

METHODS

RNA-seq data were obtained to analyze CD180 expression in gliomas and assess its prognostic value. The comprehensive immune infiltration analysis was performed. Single-cell RNA-seq (scRNA-seq) data were used to examine CD180 expression distribution at the cellular level. CD180-overexpression macrophages were co-cultured with three glioma cell lines. The effects on glioma cell behavior were evaluated through qRT-PCR, Western blot, CCK-8 assay, EdU assay, Transwell assay, TUNEL assay, and flow cytometry. Differentially expressed genes (DEGs) and their potential biological functions were analyzed between different CD180 expression groups. Consensus clustering was used to identify CD180-related glioma subtypes.

RESULTS

CD180 was significantly upregulated in glioma samples and associated with poor prognosis. High CD180 expression was correlated with increased immune cell infiltration, particularly macrophages, and elevated levels of immune checkpoints. Analysis of scRNA-seq data revealed the predominant expression of CD180 in macrophages within the glioma TME. In vitro experiments demonstrated that CD180-overexpression macrophages promoted glioma cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT), while decreasing apoptosis. Mutations in TP53 and PTEN were significantly more prevalent in the high CD180 expression group. We identified nine chemotherapeutic agents that were more effective in glioma patients with high CD180 expression. Additionally, two CD180-related glioma subtypes with distinct prognosis were identified.

CONCLUSIONS

This study confirmed the prognostic role of CD180 in glioma and its involvement in immunosuppressive regulation and malignant phenotype promotion. Therefore, CD180 was considered as a promising target for immunotherapeutic strategies in glioma treatment.

Solid cancer-directed CAR T cell therapy that attacks both tumor and immunosuppressive cells via targeting PD-L1

Chimeric antigen receptor (CAR) T cell therapy has encountered limited success in solid tumors. The lack of dependable antigens and the immunosuppressive tumor microenvironment (TME) are major challenges. Within the TME, tumor cells along with immunosuppressive cells employ an immune-evasion mechanism that upregulates programmed death ligand 1 (PD-L1) to deactivate effector T cells; this makes PD-L1 a reliable, universal target for solid tumors. We developed a novel PD-L1 CAR (MC9999) using our humanized anti-PD-L1 monoclonal antibody, designed to simultaneously target tumor and immunosuppressive cells. The antigen-specific antitumor effects of MC9999 CAR T cells were observed consistently across four solid tumor models: breast cancer, lung cancer, melanoma, and glioblastoma multiforme (GBM). Notably, intravenous administration of MC9999 CAR T cells eradicated intracranially established LN229 GBM tumors, suggesting penetration of the blood-brain barrier. The proof-of-concept data demonstrate the cytolytic effect of MC9999 CAR T cells against immunosuppressive cells, including microglia HMC3 cells and M2 macrophages. Furthermore, MC9999 CAR T cells elicited cytotoxicity against primary tumor-associated macrophages within GBM tumors. The concept of targeting both tumor and immunosuppressive cells with MC9999 was further validated using CAR T cells derived from cancer patients. These findings establish MC9999 as a foundation for the development of effective CAR T cell therapies against solid tumors.

Extracellular Vesicles from Plasma of Patients with Glioblastoma Promote Invasion of Glioblastoma Cells Even After Tumor Resection

Background: Glioblastoma (GB) is a highly aggressive tumor, whose progression is mediated by secretion of extracellular vesicles (EVs), which can pass the brain-blood barrier and be found in the plasma. Here, we performed a comparative analysis of the effects of EVs from the plasma of healthy donors (hEVs) and GB patients before (bEVs) and after (aEVs) tumor surgical resection on invasion of normal astrocytes and GB cells. Methods: We performed the transwell invasion assay, analyzed MAP kinases activation by Western blotting, studied SNAI1/SNAI2 cellular localization by confocal microscopy, measured cadherins expression by flow cytometry, and analyzed secretion of cytokines, which regulate migration and inflammation, by immunoassay. Results: hEVs did not affect invasion of astrocytes and GB cells, there was down-regulated cadherins expression in astrocytes, while there was increased E- and N-cadherin expression in GB cells. hEVs increased the secretion of inflammation and adhesion regulators both in astrocytes and GB cells. bEVs enhanced the invasion of GB cells but not of astrocytes via MAP AKT, JNK1/2/3, and p38 kinases activation, stimulated the clasterization of SNAI1 in the GB cell nucleus, promoted an E/N cadherin switch, and caused the secretion of inflammation and adhesion regulators in astrocytes and GB cells. aEVs exhibited the most of pro-oncogenic effects of bEVs (stimulation of GB cell invasion, SNAI1 nuclear localization, JNK1/2/3 activation, E/N cadherin switch, and secretion of inflammation and adhesion regulators in astrocytes and GB cells). However, aEVs effects were less pronounced than those of bEVs. Conclusions: In our study, we revealed common and different effects of plasma-derived hEVs, aEVs, and bEVs. hEVs can stimulate some pro-oncogenic effects in GB cells. Being less tumorigenic then bEVs, aEVs are still able to promote invasion of GB cells, probably remaining after tumor resection.

Indoleamine 2,3-dioxygenase-1 involves in CD8+T cell exhaustion in glioblastoma via regulating tryptophan levels

Indoleamine 2,3-dioxygenase-1 (IDO-1) is an enzyme that catalyzes the metabolism of tryptophan (Trp). It is expressed in limited amounts in normal tissues but significantly upregulated during inflammation and infection. Various inflammatory factors, especially IFN-γ, can induce the expression of IDO-1. While extensive research has been conducted on the role of IDO-1 in tumors, its specific role in complex central nervous system tumors such as glioblastoma (GBM) remains unclear. This study aims to explore the role of IDO-1 in the development of GBM and analyze its association with tryptophan levels and CD8+T cell exhaustion in the tumor region. To achieve this, we constructed an orthotopic mouse glioblastoma tumor model to investigate the specific mechanisms between IDO-1, GBM, and CD8+T cell exhaustion. Our results showed that IDO-1 can promote CD8+T cell exhaustion by reducing tryptophan levels. When IDO-1 was knocked down in glioblastoma cells, other cells within the tumor microenvironment upregulated IDO-1 expression to compensate for the loss and enhance immunosuppressive effects. Therefore, the data suggest that the GBM microenvironment controls tryptophan levels by regulating IDO-1 expression, which plays a critical role in immune suppression. These findings support the use of immune therapy in combination with IDO-1 inhibitors or tryptophan supplementation as a potential treatment strategy.

Endocannabinoid Receptor 2 Function is Associated with Tumor-Associated Macrophage Accumulation and Increases in T Cell Number to Initiate a Potent Antitumor Response in a Syngeneic Murine Model of Glioblastoma

Introduction: Glioblastoma patients have a highly immunosuppressive tumor microenvironment and systemic immunosuppression that comprise a major barrier to immune checkpoint therapy. Based on the production of endocannabinoids by glioblastomas, we explored involvement of endocannabinoid receptor 2 (CB2R), encoded by the CNR2 gene, which is predominantly expressed by immune cells, in glioblastoma-related immunosuppression. Materials & Methods: Bioinformatics of human glioblastoma databases was used to correlate enzymes involved in the synthesis and degradation of endocannabinoids, as well as CB2Rs, with patient overall survival. Intrastriatal administration of luciferase-expressing, murine GL261 glioblastoma cells was used to establish in in vivo glioblastoma model for characterization of tumor growth and intratumoral immune cell infiltration, as well as provide immune cells for in vitro co-culture experiments. Involvement of CB2Rs was determined by treatment with CB2R agonist (GW405833) or CB2R antagonist (AM630). ELISA, FACS, and immunocytochemistry were used to determine perforin, granzyme B, and surface marker levels. Results: Bioinformatics of human glioblastoma databases showed high expression of CB2R and elevated endocannabinoid production correlated with poorer prognosis, and involved immune-associated pathways. AM630treatment of GL261 glioblastoma-bearing mice induced a potent antitumor response, with survival plateauing at 50% on Day 40, when all control mice (median survival 28 days) and mice treated with GW405833 (median survival 21 days) had died. Luciferase tumor imaging revealed accelerated tumor growth by GW405833 treatment, but stable or regressing tumors in AM630-treated mice. Notably, in spleens, AM630 treatment caused an 83% decrease in monocytes/macrophages, and 1.8- and 1.6-fold increases in CD8+ and CD4+ cells, respectively. Within tumors, there was a corresponding decrease in tumor-associated macrophages (TAMs) and increase in CD8+ T cells. In vitro, lymphocytes from AM630-treated mice showed greater cytotoxic function (increased percentage of perforin- and granzyme B-positive CD8+ T cells). Discussion: These results suggest that inhibition of CB2R enhances both immunosuppressive TAM infiltration and systemic T-cell suppression through CB2R activation, and that inhibition of CB2Rs can potently counter both the immunosuppressive tumor microenvironment, as well as systemic immunosuppression in glioblastoma.

Using Multi-Omics Analysis to Explore Diagnostic Tool and Optimize Drug Therapy Selection for Patients with Glioma Based on Cross-Talk Gene Signature

Background

The heterogeneity of prognosis and treatment benefits among patients with gliomas is due to tumor microenvironment characteristics. However, biomarkers that reflect microenvironmental characteristics and predict the prognosis of gliomas are limited. Therefore, we aimed to develop a model that can effectively predict prognosis, differentiate microenvironment signatures, and optimize drug selection for patients with glioma.

Materials and Methods

The CIBERSORT algorithm, bulk sequencing analysis, and single-cell RNA (scRNA) analysis were employed to identify significant cross-talk genes between M2 macrophages and cancer cells in glioma tissues. A predictive model was constructed based on cross-talk gene expression, and its effect on prognosis, recurrence prediction, and microenvironment characteristics was validated in multiple cohorts. The effect of the predictive model on drug selection was evaluated using the OncoPredict algorithm and relevant cellular biology experiments.

Results

A high abundance of M2 macrophages in glioma tissues indicates poor prognosis, and cross-talk between macrophages and cancer cells plays a crucial role in shaping the tumor microenvironment. Eight genes involved in the cross-talk between macrophages and cancer cells were identified. Among them, periostin (POSTN), chitinase 3 like 1 (CHI3L1), serum amyloid A1 (SAA1), and matrix metallopeptidase 9 (MMP9) were selected to construct a predictive model. The developed model demonstrated significant efficacy in distinguishing patient prognosis, recurrent cases, and characteristics of high inflammation, hypoxia, and immunosuppression. Furthermore, this model can serve as a valuable tool for guiding the use of trametinib.

Conclusions

In summary, this study provides a comprehensive understanding of the interplay between M2 macrophages and cancer cells in glioma; utilizes a cross-talk gene signature to develop a predictive model that can predict the differentiation of patient prognosis, recurrence instances, and microenvironment characteristics; and aids in optimizing the application of trametinib in glioma patients.

Curcumin Derivatives in Medicinal Chemistry: Potential Applications in Cancer Treatment

Curcumin, a naturally occurring compound found in the rhizome of Curcuma plants, particularly in turmeric (Curcuma longa L.), exhibits a broad range of biological activities, including anti-inflammatory, antioxidant, and anticancer properties. Curcumin has demonstrated effectiveness in inhibiting tumor growth, arousing interest for its potential in treating various cancers, such as breast, lung, prostate, and brain cancers. However, the clinical application of curcumin is limited due to its low chemical stability, poor water solubility, and low bioavailability. In response to these challenges, structural modifications of curcumin have been explored to improve its pharmacological properties, including enhanced anticancer selectivity index and bioavailability. This review highlights promising chemical modifications of curcumin that could lead to the development of more effective anticancer therapies. By functionalizing the parent curcumin molecule, researchers aim to create more stable and bioavailable compounds with enhanced therapeutic potential, making curcumin derivatives promising candidates for medical applications.

Potential Mechanism and Involvement of p120-Catenin in the Malignant Biology of Glioma

OBJECTIVE

This study analyzed the influence of p120-catenin (catenin [cadherin-associated protein], delta 1 [CTNND1]) on the malignant characteristics of glioma and elucidated the potential underlying mechanism.

METHODS

The p120 expression level was assessed in the brain tissues of 42 glioma patients and 10 patients with epilepsy by using the immunohistochemical method. Meanwhile, quantitative polymerase chain reaction (QT-PCR) technology was employed to assess the expression of p120 in the brain tissues of 71 glioma patients and 13 epilepsy patients. LN229, U251, and U87 glioma cells were used for in vitro analysis and categorized into four treatment groups : siRNA-blank control (BC) group (no RNA sequence was transfected), siRNA-negative control (NC) group (transfected control RNA sequences with no effect), and siRNA-1 and siRNA-2 groups (two p120-specific interfering RNA transfection). p120 expression in these treatment groups was quantified by western blotting assay. The migratory and invasive capabilities of glioma cells were studied by wound healing assay and Transwell invasion assay, respectively, under different treatment conditions. MTT (3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide) assay and cell cycle and apoptosis assay were used to determine glioma cell proliferation and apoptosis, respectively. Enzymelabeled assay was performed to measure intracellular calcium ion concentration. Immunofluorescence assay was performed for determining microtubule formation and glioma cell distribution.

RESULTS

Brain tissues of the glioma group exhibited a remarkable increase in the p120 expression level as compared to brain tissues of the nontumor group (p<0.05). Furthermore, a strong positive correlation was noted between the malignancy degree in glioma brain tissues and p120 expression in Western blotting (r=0.906, p<0.0001) and QT-PCR (F=830.6, p<0.01). Compared to the BC and NC groups, the siRNA transfection groups showed a significant suppression in p120 expression in glioma cells (p<0.05), with a marked attenuation in the invasive, migratory, and proliferative capabilities of glioma cells as well as an increase in apoptotic potential (p<0.05). Enzyme-labeled assay showed a remarkable increase in calcium concentration in glioma cells after siRNA treatment. Immunofluorescence assay revealed that the microtubule formation ability of glioma cells reduced after siRNA treatment.

CONCLUSION

p120 has a pivotal involvement in facilitating glioma cell invasion and proliferation by potentially modulating these processes through its involvement in microtubule formation and regulation of intracellular calcium ion levels.

VCAN in the extracellular matrix drives glioma recurrence by enhancing cell proliferation and migration

Introduction

Gliomas are the most prevalent primary malignant intracranial tumors, characterized by high rates of therapy resistance, recurrence, and mortality. A major factor contributing to the poor prognosis of gliomas is their ability to diffusely infiltrate surrounding and even distant brain tissues, rendering complete total resection almost impossible and leading to frequent recurrences. The extracellular matrix (ECM) plays a key role in the tumor microenvironment and may significantly influence glioma progression, recurrence, and therapeutic response.

Methods

In this study, we first identified the ECM and the Versican (VCAN), a key ECM protein, as critical contributors to glioma recurrence through a comprehensive analysis of transcriptomic data comparing recurrent and primary gliomas. Using single-cell sequencing, we revealed heterogeneous distribution patterns and extensive intercellular communication among ECM components. External sequencing and immunohistochemical (IHC) staining further validated that VCAN is significantly upregulated in recurrent gliomas and is associated with poor patient outcomes.

Results

Functional assays conducted in glioma cell lines overexpressing VCAN demonstrated that VCAN promotes cell proliferation and migration via the PI3K/Akt/AP-1 signaling pathway. Furthermore, inhibiting the PI3K/Akt pathway effectively blocked VCAN-mediated glioma progression.

Conclusion

These findings provide valuable insights into the mechanisms underlying glioma recurrence and suggest that targeting both VCAN and the PI3K/Akt pathway could represent a promising therapeutic strategy for managing recurrent gliomas.

Deciphering the CNS-glioma dialogue: Advanced insights into CNS-glioma communication pathways and their therapeutic potential

The field of cancer neuroscience has rapidly evolved, shedding light on the complex interplay between the nervous system and cancer, with a particular focus on the relationship between the central nervous system (CNS) and gliomas. Recent advancements have underscored the critical influence of CNS activity on glioma progression, emphasizing the roles of neurons and neuroglial cells in both the onset and evolution of gliomas. This review meticulously explores the primary communication pathways between the CNS and gliomas, encompassing neuro-glioma synapses, paracrine mechanisms, extracellular vesicles, tunneling nanotubes, and the integrative CNS-immune-glioma axis. It also evaluates current and emerging therapeutic interventions aimed at these pathways and proposes forward-looking perspectives for research in this domain.

Preliminary studies on changes in the amount of tryptophan metabolites in human glioma tissues

BACKGROUND

We have developed and validated methods for the determination of three major tryptophan metabolites metabolized by the kynurenine pathway, namely kynurenine (KYN), 3-hydroxykynurenine (3-HK), and 3-hydroxyanthranilic acid (3-HAA). KYN and 3-HK were determined using RP-HPLC-UV, and 3-HAA using RP-HPLC-FL. We then developed a comparative method based on CE-UV. The developed methods were validated and 36 samples of human brain glioma tissue homogenates were assayed in all 4 grades of malignancy, and the concentration levels of assayed metabolites were compared with available clinical data.

RESULTS

Each of the methods is characterized by high precision, accuracy and repeatability, and the determined LOQ values indicate the possibility of performing quantitative analysis on the available samples of human glioma tumors (36 samples in grades G1-G4). The concentration values of selected metabolites obtained using HPLC methods were subjected to statistical analysis and preliminary clinical data processing. We found statistically significant differences in the concentrations of KYN, 3-HK and 3-HAA between the various grades of the disease, and characterized these differences more precisely by means of the Dunn-Bonferroni post hoc test. We did not find that the patient's environment or habits significantly affected the metabolites concentration of the study samples population. In addition, we showed a high positive correlation between KYN, 3-HK and 3-HAA, which appears to be a characteristic that describes metabolic changes of Trp in relation to KYN, 3-HK and 3-HAA, and indicates potential diagnostic value.

SIGNIFICANCE

The preliminary studies carried out contribute new knowledge on the molecular basis of human brain glioma. They also provide valuable information useful for the development of glioma diagnostics, differentiation of disease grades and assessment of the patient's condition. The obtained relationships between metabolite concentrations and the grade of malignancy of the disease and correlations between metabolite concentrations constitute the basis for further broader biochemical and clinical analysis.

Expression of CREBBP and EP300 Associated With Tumor Volume in Patients With Grade-3 Glioma: A Retrospective Analysis

Background

Reliable predictive data are crucial for making accurate treatment decisions in glioma patients, but it can be challenging to obtain due to limited information in many cases. Numerous research studies have indicated the involvement of cyclic adenosine monophosphate (cAMP)-response element binding protein (CREBBP) and E1A binding protein p300 (EP300) in tumorigenesis and tumor progression across various types.

Methods

The messenger RNA (mRNA) expression levels of CREBBP and EP300 were retrospectively analyzed in 17 grade-3 glioma patients. The SYBR Green real-time polymerase chain reaction (RT-PCR) technique was employed for mRNA expression analysis, with the glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH) used as a reference gene for data normalization. In addition, the relationship between CREBBP, EP300 expression and patients' clinical information, imaging features, histologic features, immune factors, and overall survival was assessed through univariate analyses.

Results

The analysis of the data unveiled a statistically significant upregulation of CREBBP and EP300 mRNA expression levels in large gliomas as compared with their smaller counterparts (P < .05). Histological examination using hematoxylin and eosin (H&E) staining exhibited marked cellular heterogeneity, with heightened cell density observed specifically within tumors displaying elevated CREBBP expression levels. In contrast, there was a substantial downregulation of complement 3 and complement 4 within larger tumor volumes when compared with smaller ones (P < .05). However, these findings do not serve as clinically relevant prognostic indicators for glioma.

Conclusions

It is suggested that higher expression levels of CREBBP and EP300 are positively associated with increased tumor volume. Inhibition of CREBBP and EP300 enhances local immunogenicity, leading to the recruitment of immune cells and release of cytokines for effective tumor eradication, ultimately resulting in the inhibition of tumor growth.

Emerging role of tumor microenvironmental nutrients and metabolic molecules in ferroptosis: Mechanisms and clinical implications

In recent years, ferroptosis has gradually attracted increasing attention because of its important role in tumors. Ferroptosis resistance is an important cause of tumor metastasis, recurrence and drug resistance. Exploring the initiating factors and specific mechanisms of ferroptosis has become a key strategy to block tumor progression and improve drug sensitivity. As the external space in direct contact with tumor cells, the tumor microenvironment has a great impact on the biological function of tumor cells. The relationships between abnormal environmental characteristics (hypoxia, lactic acid accumulation, etc.) in the microenvironment and ferroptosis of tumor cells has not been fully characterized. This review focuses on the characteristics of the tumor microenvironment and summarizes the mechanisms of ferroptosis under different environmental factors, aiming to provide new insights for subsequent targeted therapy. Moreover, considering the presence of anticancer drugs in the microenvironment, we further summarize the mechanisms of ferroptosis to provide new strategies for the sensitization of tumor cells to drugs.

Glioblastoma Tumor Microenvironment: An Important Modulator for Tumoral Progression and Therapy Resistance

The race to find an effective treatment for glioblastoma (GBM) remains a critical topic, because of its high aggressivity and impact on survival and the quality of life. Currently, due to GBM's high heterogeneity, the conventional treatment success rate and response to therapy are relatively low, with a median survival rate of less than 20 months. A new point of view can be provided by the comprehension of the tumor microenvironment (TME) in pursuance of the development of new therapeutic strategies to aim for a longer survival rate with an improved quality of life and longer disease-free interval (DFI). The main components of the GBM TME are represented by the extracellular matrix (ECM), glioma cells and glioma stem cells (GSCs), immune cells (microglia, macrophages, neutrophils, lymphocytes), neuronal cells, all of them having dynamic interactions and being able to influence the tumoral growth, progression, and drug resistance thus being a potential therapeutic target. This paper will review the latest research on the GBM TME and the potential therapeutic targets to form an up-to-date strategy.

High expression of SIGLEC7 may promote M2-type macrophage polarization leading to adverse prognosis in glioma patients

Introduction

Gliomas are the most common primary intracranial tumors, known for their high invasiveness and destructiveness. Sialic acid-binding immunoglobulin-like lectin 7 (SIGLEC7) is present in various immune cells, especially macrophages, and significantly affects immune homeostasis and cancer cell response. However, research on the role and prognostic impact of SIGLEC7 in glioma patients is currently limited.

Methods

We utilized transcriptomic data from 702 glioma patients in The Cancer Genome Atlas (TCGA) and 693 glioma patients in the Chinese Glioma Genome Atlas (CGGA), along with clinical samples we collected, to comprehensively investigate the impact of SIGLEC7 on glioma expression patterns, biological functions, and prognostic value. We focused on its role in glioma-related immune responses and immune cell infiltration and analyzed its expression at the single-cell level. Finally, we validated the role of SIGLEC7 in gliomas through tissue and cell experiments.

Results

SIGLEC7 expression was significantly increased in glioma patients with malignant characteristics. Survival analysis indicated that glioma patients with high SIGLEC7 expression had significantly lower survival rates. Gene function analysis revealed that SIGLEC7 is primarily involved in immune and inflammatory responses and is strongly negatively correlated with tumor-associated immune regulation. Additionally, the expression of most immune checkpoints was positively correlated with SIGLEC7, and immune cell infiltration analysis clearly demonstrated a significant positive correlation between SIGLEC7 expression and M2 macrophage infiltration levels. Single-cell analysis, along with tissue and cell experiments, confirmed that SIGLEC7 enhances macrophage polarization towards the M2 phenotype, thereby promoting glioma invasiveness through the immunosuppressive effects of M2 macrophages. Cox regression analysis and the establishment of survival prediction models indicated that high SIGLEC7 expression is an unfavorable prognostic factor for glioma patients.

Discussion

High SIGLEC7 expression predicts poor prognosis in glioma patients and is closely associated with M2 macrophages in the tumor environment. In the future, SIGLEC7 may become a promising target for glioma immunotherapy.

Comprehensive analysis of the prognostic and immunological signature of TNFAIP8 family genes in human glioma

TNFAIP8 family molecules have been recognized for their involvement in the progression of tumors across a range of cancer types. Emerging experimental data suggests a role for certain TNFAIP8 family molecules in the development of glioma. Nonetheless, the comprehensive understanding of the genomic alterations, prognostic significance, and immunological profiles of TNFAIP8 family molecules in glioma remains incomplete. In the study, using the comprehensive bioinformatics tools, we explored the unique functions of 4 TNFAIP8 members including TNFAIP8, TNFAIP8L1, TNFAIP8L2 and TNFAIP8L3 in glioma. The expressions of TNFAIP8, TNFAIP8L1, TNFAIP8L2, and TNFAIP8L3 were notably upregulated in glioma tissues compared to normal tissues. Furthermore, survival analysis indicated that elevated expression levels of TNFAIP8, TNFAIP8L1 and TNFAIP8L2 were correlated with unfavorable outcomes in terms of overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI) among glioma patients. Genetic modifications, such as mutations and copy number alterations, within the TNFAIP8 family exhibited a significant association with extended OS, DSS and PFS in individuals diagnosed with glioma. The findings suggest a noteworthy correlation between TNFAIP8 family members and the age and 1p/19q codeletion status of glioma patients. We also found that there were significant relationships between TNFAIP8 family expression and tumor immunity in glioma. Furthermore, functional annotation of TNFAIP8 family members and their co-expressed genes in gliomas was carried out using GO and KEGG pathway analysis. The GO analysis revealed that the primary biological processes influenced by the TNFAIP8 family co-expressed genes included cell chemotaxis, temperature homeostasis, and endocytic vesicle formation. Additionally, the KEGG analysis demonstrated that TNFAIP8 family co-expressed genes are involved in regulating various pathways such as inflammatory mediator regulation of TRP channels, pathways in cancer, prolactin signaling pathway, and Fc gamma R-mediated phagocytosis. Overall, the findings suggest that TNFAIP8 family members may play a significant role in the development of glioma and have the potential to serve as prognostic indicators and therapeutic targets for individuals with glioma.

Diffusion kurtosis imaging-based habitat analysis identifies high-risk molecular subtypes and heterogeneity matching in diffuse gliomas

OBJECTIVE

High-risk types of diffuse gliomas in adults include isocitrate dehydrogenase (IDH) wild-type glioblastomas and grade 4 astrocytomas. Achieving noninvasive prediction of high-risk molecular subtypes of gliomas is important for personalized and precise diagnosis and treatment.

METHODS

We retrospectively collected data from 116 patients diagnosed with adult diffuse gliomas. Multiple high-risk molecular markers were tested, and various habitat models and whole-tumor models were constructed based on preoperative routine and diffusion kurtosis imaging (DKI) sequences to predict high-risk molecular subtypes of gliomas. Feature selection and model construction utilized Least absolute shrinkage and selection operator (LASSO) and support vector machine (SVM). Finally, the Wilcoxon rank-sum test was employed to explore the correlation between habitat quantitative features (intra-tumor heterogeneity score，ITH score) and heterogeneity, as well as high-risk molecular subtypes.

RESULTS

The results showed that the habitat analysis model based on DKI performed remarkably well (with AUC values reaching 0.977 and 0.902 in the training and test sets, respectively). The model's performance was further enhanced when combined with clinical variables. (The AUC values were 0.994 and 0.920, respectively.) Additionally, we found a close correlation between ITH score and heterogeneity, with statistically significant differences observed between high-risk and non-high-risk molecular subtypes.

INTERPRETATION

The habitat model based on DKI is an ideal means for preoperatively predicting high-risk molecular subtypes of gliomas, holding significant value for noninvasively alerting malignant gliomas and those with malignant transformation potential.

Hypoxia conduces the glioma progression by inducing M2 macrophage polarization via elevating TNFSF9 level in a histone-lactylation-dependent manner

Hypoxia is a critical factor contributing to a poor prognosis and challenging glioma therapy. Previous studies have indicated that hypoxia drives M2 polarization of macrophages and promotes cancer progression in various solid tumors. However, the more complex and diverse mechanisms underlying this process remain to be elucidated. Here, we aimed to examine the functions of hypoxia in gliomas and preliminarily investigate the underlying mechanisms of M2 macrophage polarization caused by hypoxia. We found that hypoxia significantly enhances the malignant phenotypes of U87 and U251 cells by regulating glycolysis. In addition, hypoxia mediated accumulation of the glycolysis product [lactic acid (LA)], which is subsequently absorbed by macrophages to induce its M2 polarization, and this process is reverted by both the glycolysis inhibitor and silenced monocarboxylate transporter (MCT-1) in macrophages, indicating that M2 macrophage polarization is associated with the promotion of glycolysis by hypoxia. Interestingly, we also found that hypoxia mediated LA accumulation in glioma cells upon uptake by macrophages upregulates H3K18La expression and promotes tumor necrosis factor superfamily member 9 (TNFSF9) expression in a histone-lactylation-dependent manner based on the results of chromatin immunoprecipitation sequencing (ChIP seq) enrichment analysis. Subsequent in vitro and in vivo experiments further indicated that TNFSF9 facilitated glioma progression. Mechanistically, hypoxia-mediated LA accumulation in glioma cells is taken up by macrophages and then induces its M2 macrophage polarization by regulating TNFSF9 expression via MCT-1/H3K18La signaling, thus facilitating the malignant progression of gliomas.NEW & NOTEWORTHY Our study revealed that hypoxia induces the production of LA accumulation through glycolysis in glioma cells, which is subsequently absorbed by macrophages and leads to its M2 polarization via the MCT-1/H3K18La/TNFSF9 axis, ultimately significantly promoting the malignant progression of glioma cells. These findings are novel and noteworthy as they provide insights into the connection between energy metabolism and epigenetics in gliomas.

Engineered Cell Membrane-Coated Nanoparticles: New Strategies in Glioma Targeted Therapy and Immune Modulation

Gliomas, the most prevalent primary brain tumors, pose considerable challenges due to their heterogeneity, intricate tumor microenvironment (TME), and blood-brain barrier (BBB), which restrict the effectiveness of traditional treatments like surgery and chemotherapy. This review provides an overview of engineered cell membrane technologies in glioma therapy, with a specific emphasis on targeted drug delivery and modulation of the immune microenvironment. This study investigates the progress in engineered cell membranes, encompassing physical, chemical, and genetic alterations, to improve drug delivery across the BBB and effectively target gliomas. The examination focuses on the interaction of engineered cell membrane-coated nanoparticles (ECM-NPs) with the TME in gliomas, emphasizing their potential to modulate glioma cell behavior and TME to enhance therapeutic efficacy. The review further explores the involvement of ECM-NPs in immunomodulation techniques, highlighting their impact on immune reactions. While facing obstacles related to membrane stability and manufacturing scalability, the review outlines forthcoming research directions focused on enhancing membrane performance. This review underscores the promise of ECM-NPs in surpassing conventional therapeutic constraints, proposing novel approaches for efficacious glioma treatment.

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.

Identification of TNFAIP6 as a reliable prognostic indicator of low-grade glioma

Glioma is the most common primary malignant tumor in the brain, characterizing by high disability rate and high recurrence rate. Although low-grade glioma (LGG) has a relative benign biological behavior, the prognosis of LGG patients still varies greatly. Glioma stem cells (GSCs) are considered as the chief offenders of glioma cell proliferation, invasion and resistance to therapies. Our study screened a series of glioma stem cell-related genes (GSCRG) based on mDNAsi and WCGNA, and finally established a reliable single-gene prognostic model through 101 combinations of 10 machine learning methods. Our result suggested that the expression level of TNFAIP6 is negatively correlated with the prognosis of LGG patients, which may be the result of pro-cancer signaling pathways activation and immunosuppression. In general, this study revealed that TNFAIP6 is a robust and valuable prognostic factor in LGG, and may be a new target for LGG treatment.

SFRP4 protein expression is reduced in high grade astrocytomas which is not caused by the methylation of its promoter

Introduction

Epigenetics play a vital role in stratifying CNS tumors and gliomas. The importance of studying Secreted frizzled-related protein 4 (SFRP4) in gliomas is to improve diffuse glioma methylation profiling. Here we examined the methylation status of SFRP4 promoter and the level of its protein expression in diffuse gliomas WHO grades 2-4.

Methods

SFRP4 expression was detected by immunohistochemistry and evaluated semi-quantitatively. In the tumor hot-spot area, the intensity of protein expression in 200 cells was determined using ImageJ (National Institutes of Health, United States). The assessment of immunopositivity was based on the IRS score (Immunoreactivity Score). Promoter methylation was examined by methylation specific-PCR (MSP) in fifty-one diffuse glioma samples and appropriate controls. Isolated DNA was treated with bisulfite conversion and afterwards used for MSP. Public databases (cBioPortal, COSMIC and LOVD) were searched to corroborate the results.

Results and discussion

SFRP4 protein expression in glioblastomas was very weak or non-existent in 86.7% of samples, moderate in 13.3%, while strong expression was not observed. The increase in astrocytoma grade resulted in SFRP4 protein decrease (p = 0.008), indicating the loss of its antagonistic role in Wnt signaling. Promoter methylation of SFRP4 gene was found in 16.3% of cases. Astrocytomas grade 2 had significantly more methylated cases compared to grade 3 astrocytomas (p = 0.004) and glioblastomas (p < 0.001), which may indicate temporal niche of methylation in grade 2. Furthermore, the expression levels of SFRP4 were high in samples with methylated SFRP4 promoter and low or missing in unmethylated cases (Pearson's R = -0.413; p = 0.003). We also investigated the association of SFRP4 changes to key Wnt regulators GSK3β and DKK3 and established a positive correlation between methylations of SFRP4 and GSK3β (Pearson's R = 0.323; p = 0.03). Furthermore, SFRP4 expression was correlated to unmethylated DKK3 (Chi square = 7.254; p = 0.027) indication that Wnt signaling antagonist is associated to negative regulator's demethylation.

Conclusion

The study contributes to the recognition of the significance of epigenetic changes in diffuse glioma indicating that restoring SFRP4 protein holds potential as therapeutic avenue. Reduced expression of SFRP4 in glioblastomas, not following promoter methylation pattern, suggests another mechanism, possible global methylation, that turns off SFRP4 expression in higher grades.