Immune checkpoint blockade in glioblastoma: from tumor heterogeneity to personalized treatment

GBM immunotherapy: Exploring molecular and clinical frontiers

GBM is the most common, aggressive, and intracranial primary brain tumor; it originates from the glial progenitor cells, has poor overall survival (OS), and has limited treatment options. In this decade, GBM immunotherapy is in trend and preferred over several conventional therapies, due to their better patient survival outcome. This review explores the clinical trials of several immunotherapeutic approaches (immune checkpoint blockers (ICBs), CAR T-cell therapy, cancer vaccines, and adoptive cell therapy) with their efficacy and safety. Despite significant progress, several challenges (viz., immunosuppressive microenvironment, heterogeneity, and blood-brain barrier (BBB)) were experienced that hamper their immunotherapeutic potential. Furthermore, these challenges were clinically studied to be resolved by multiple combinatorial approaches, discussed in the later part of the review. Thus, this review suggests the clinical use and potential of immunotherapy in GBM and provides the holistic recent knowledge and future perspectives.

Comprehensive machine learning-based integration develops a novel prognostic model for glioblastoma

In this study, we developed a new prognostic model for glioblastoma (GBM) based on an integrated machine learning algorithm. We used univariate Cox regression analysis to identify prognostic genes by combining six GBM cohorts. Based on the prognostic genes, 10 machine learning algorithms were integrated into 117 algorithm combinations, and the artificial intelligence prognostic signature (AIPS) with the greatest average C-index was chosen. The AIPS was compared with 10 previously published models by univariate Cox analysis and the C-index. We compared the differences in prognosis, tumor immune microenvironment (TIME), and immunotherapy sensitivity between the high and low AIPS score groups. The AIPS based on the random survival forest algorithm with the highest average C-index (0.868) was selected. Compared with the previous 10 prognostic models, our AIPS has the highest C-index. The AIPS was closely linked to the clinical features of GBM. We discovered that patients in the low score group had improved prognoses, a more active TIME, and were more sensitive to immunotherapy. Finally, we verified the expression of several key genes by western blotting and immunohistochemistry. We identified an ideal prognostic signature for GBM, which might provide new insights into stratified treatment approaches for GBM patients.

Prospective Molecular Targets for Natural Killer Cell Immunotherapy against Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common type of primary malignant brain tumor and has a dismal overall survival rate. To date, no GBM therapy has yielded successful results in survival for patients beyond baseline surgical resection, radiation, and chemotherapy. Immunotherapy has taken the oncology world by storm in recent years and there has been movement from researchers to implement the immunotherapy revolution into GBM treatment. Natural killer (NK) cell-based immunotherapies are a rising candidate to treat GBM from multiple therapeutic vantage points: monoclonal antibody therapy targeting tumor-associated antigens (TAAs), immune checkpoint inhibitors, CAR-NK cell therapy, Bi-specific killer cell engagers (BiKEs), and more. NK therapies often focus on tumor antigens for targeting. Here, we reviewed some common targets analyzed in the fight for GBM immunotherapy relevant to NK cells: EGFR, HER2, CD155, and IL-13Rα2. We further propose investigating the Lectin-like Transcript 1 (LLT1) and cell surface proliferating cell nuclear antigen (csPCNA) as targets for NK cell-based immunotherapy.

Microenvironmental regulation of tumor-associated neutrophils in malignant glioma: from mechanism to therapy

Glioma is the most common primary intracranial tumor in adults, with high incidence, recurrence, and mortality rates. Tumor-associated neutrophils (TANs) are essential components of the tumor microenvironment (TME) in glioma and play a crucial role in glioma cell proliferation, invasion and proneural-mesenchymal transition. Besides the interactions between TANs and tumor cells, the multi-dimensional crosstalk between TANs and other components within TME have been reported to participate in glioma progression. More importantly, several therapies targeting TANs have been developed and relevant preclinical and clinical studies have been conducted in cancer therapy. In this review, we introduce the origin of TANs and the functions of TANs in malignant behaviors of glioma, highlighting the microenvironmental regulation of TANs. Moreover, we focus on summarizing the TANs-targeted methods in cancer therapy, aiming to provide insights into the mechanisms and therapeutic opportunities of TANs in the malignant glioma microenvironment.

Advances in the treatment of IDH-mutant gliomas

PURPOSE OF REVIEW

Isocitrate dehydrogenase (IDH) mutation is a defining molecular driver of WHO grade 2-4 astrocytomas and oligodendrogliomas. In this article, we review the recent therapeutic approaches specifically targeting IDH-mutant gliomas and summarize ongoing clinical trials in this population.

RECENT FINDINGS

The IDH inhibitor vorasidenib recently demonstrated its efficacy after surgical resection in grade 2 IDH-mutated gliomas. Several studies in patients with IDH-mutant gliomas are currently exploring various strategies to target IDH mutations, including the use of small-molecule inhibitors, immunotherapies, peptide vaccines and agents targeting metabolic and epigenomic vulnerabilities.

SUMMARY

Mutant-IDH targeting holds significant promise in treating progressive or recurrent IDH-mutant gliomas. Recent results with IDH inhibitors will change practice and influence the existing guidelines in a near future.

Open-Source Throttling of CD8+ T Cells in Brain with Low-Intensity Focused Ultrasound-Guided Sequential Delivery of CXCL10, IL-2, and aPD-L1 for Glioblastoma Immunotherapy

Improving clinical immunotherapy for glioblastoma (GBM) relies on addressing the immunosuppressive tumor microenvironment (TME). Enhancing CD8+ T cell infiltration and preventing its exhaustion holds promise for effective GBM immunotherapy. Here, a low-intensity focused ultrasound (LIFU)-guided sequential delivery strategy is developed to enhance CD8+ T cells infiltration and activity in the GBM region. The sequential delivery of CXC chemokine ligand 10 (CXCL10) to recruit CD8+ T cells and interleukin-2 (IL-2) to reduce their exhaustion is termed an "open-source throttling" strategy. Consequently, up to 3.39-fold of CD8+ T cells are observed with LIFU-guided sequential delivery of CXCL10, IL-2, and anti-programmed cell death 1 ligand 1 (aPD-L1), compared to the free aPD-L1 group. The immune checkpoint inhibitors (ICIs) therapeutic efficacy is substantially enhanced by the reversed immunosuppressive TME due to the expansion of CD8+ T cells, resulting in the elimination of tumor, prolonged survival time, and long-term immune memory establishment in orthotopic GBM mice. Overall, LIFU-guided sequential cytokine and ICIs delivery offers an "open-source throttling" strategy of CD8+ T cells, which may present a promising strategy for brain-tumor immunotherapy.

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.

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.

Immunomodulatory signalling networks in glioblastoma multiforme: a comprehensive review of therapeutic approaches

Glioblastoma multiforme is a very aggressive type of cancer with high mortality and poor prognosis worldwide. Advanced treatment options with an understanding of the molecules and signalling mechanisms involved in this type of cancer have the potential to increase targeted therapy and decrease off-target effects, resistance, and recurrence. Glioblastoma multiforme (GBM) presents a complex tumour microenvironment with numerous cellular components and an extracellular matrix comprising multiple components. A deeper understanding of these components and corresponding signalling pathways can increase the success of immune checkpoint inhibitors in the treatment of GBM. The discovery of specific molecular changes and biomarkers has led to the investigation of tailored treatments for individual patients. Combination therapies targeting multiple pathways or utilizing different modalities are emerging as a promising strategy albeit with challenges in drug delivery to the brain. The review presents a comprehensive update of the various immunomodulatory signalling networks in GBM and highlights the corresponding therapeutic approaches by targeting them.

GPR65 contributes to constructing immunosuppressive microenvironment in glioma

Glioma, especially glioblastoma patients, present highly heterogeneous and immunosuppressive microenvironment, leading to their poor response to treatment and survival. Targeting the tumor microenvironment is considered a promising therapeutic strategy. M2 macrophages are highly infiltrated in glioma tissue, even up to 50% of the total number of bulk tissue cells. Here, we identified GPR65 as the hub gene of the M2 macrophage-related module in glioma through WGCNA analysis. The expression and prognosis analysis suggested that GPR65 was positively correlated with the malignancy and poor prognosis of glioma, and the heterogeneity analysis found that GPR65 was highly expressed in the vascular proliferation area of glioma, which matched the spatial expression characteristics of M2 macrophages. We further verified that GPR65 was highly expressed in macrophages but not tumor cells in the glioma microenvironment by single-cell data analysis and immunofluorescence. Most importantly, we found that inhibition of GPR65 was sufficient to reduce macrophages' polarization response to glioma cell and break the malignant cooperation with glioma cells. Our study reports the expression characteristics and malignant behavior of GPR65 in the glioma microenvironment, which provides a new alternative target of treatment to glioma microenvironment.

Pickering emulsion-guided monomeric delivery of monophosphoryl lipid A for enhanced vaccination

Immunological adjuvants are vaccine components that enhance long-lasting adaptive immune responses to weakly immunogenic antigens. Monophosphoryl lipid A (MPLA) is a potent and safe vaccine adjuvant that initiates an early innate immune response by binding to the Toll-like receptor 4 (TLR4). Importantly, the binding and recognition process is highly dependent on the monomeric state of MPLA. However, current vaccine delivery systems often prioritize improving the loading efficiency of MPLA, while neglecting the need to maintain its monomeric form for optimal immune activation. Here, we introduce a Pickering emulsion-guided MPLA monomeric delivery system (PMMS), which embed MPLA into the oil-water interface to achieve the monomeric loading of MPLA. During interactions with antigen-presenting cells, PMMS functions as a chaperone for MPLA, facilitating efficient recognition by TLR4 regardless of the presence of lipopolysaccharide-binding proteins. At the injection site, PMMS efficiently elicited local immune responses, subsequently promoting the migration of antigen-internalized dendritic cells to the lymph nodes. Within the draining lymph nodes, PMMS enhanced antigen presentation and maturation of dendritic cells. In C57BL/6 mice models, PMMS vaccination provoked potent antigen-specific CD8+ T cell-based immune responses. Additionally, PMMS demonstrated strong anti-tumor effects against E.G7-OVA lymphoma. These data indicate that PMMS provides a straightforward and efficient strategy for delivering monomeric MPLA to achieve robust cellular immune responses and effective cancer immunotherapy.

The roles of tertiary lymphoid structures in genitourinary cancers: molecular mechanisms, therapeutic strategies, and clinical applications

The presence of tertiary lymphoid structures (TLSs) associated with distinct treatment efficacy and clinical prognosis has been identified in various cancer types. However, the mechanistic roles and clinical implications of TLSs in genitourinary (GU) cancers remain incompletely explored. Despite their potential role as predictive markers described in numerous studies, it is essential to comprehensively evaluate the characteristics of TLSs, including drivers of formation, structural foundation, cellular compositions, maturation stages, molecular features, and specific functionality to maximize their positive impacts on tumor-specific immunity. The unique contributions of these structures to cancer progression and biology have fueled interest in these structures as mediators of antitumor immunity. Emerging data are trying to explore the effects of therapeutic interventions targeting TLSs. Therefore, a better understanding of the molecular and phenotypic heterogeneity of TLSs may facilitate the development of TLSs-targeting therapeutic strategies to obtain optimal clinical benefits for GU cancers in the setting of immunotherapy. In this review, the authors focus on the phenotypic and functional heterogeneity of TLSs in cancer progression, current therapeutic interventions targeting TLSs and the clinical implications and therapeutic potential of TLSs in GU cancers.

Caspase-4 in glioma indicates deterioration and unfavorable prognosis by affecting tumor cell proliferation and immune cell recruitment

Gliomas are the most common malignant tumors of the central nervous system, accounting for approximately 80% of all malignant brain tumors. Accumulating evidence suggest that pyroptosis plays an essential role in the progression of cancer. Unfortunately, the effect of the pyroptosis-related factor caspase-4 (CASP4) on immunotherapy and drug therapy for tumors has not been comprehensively investigated. In this study, we systematically screened six hub genes by pooling differential pyroptosis-related genes in The Cancer Genome Atlas (TCGA) glioma data and the degree of centrality of index-related genes in the protein-protein interaction network. We performed functional and pathway enrichment analyses of the six hub genes to explore their biological functions and potential molecular mechanisms. We then investigated the importance of CASP4 using Kaplan-Meier survival analysis of glioma patients. TCGA and the Chinese Glioma Genome Atlas (CGGA) databases showed that reduced CASP4 expression leads to the potent clinical deterioration of glioma patients. Computational analysis of the effect of CASP4 on the infiltration level and recruitment of glioma immune cells revealed that CASP4 expression was closely associated with a series of tumor-suppressive immune checkpoint molecules, chemokines, and chemokine receptors. We also found that aberrant CASP4 expression correlated with chemotherapeutic drug sensitivity. Finally, analysis at the cellular and tissue levels indicated an increase in CASP4 expression in glioma, and that CASP4 inhibition significantly inhibited the proliferation of glioma cells. Thus, CASP4 is implicated as a new prognostic biomarker for gliomas with the potential to further guide immunotherapy and chemotherapy strategies for glioma patients.

Epigenetic clocks and gliomas: unveiling the molecular interactions between aging and tumor development

Gliomas, the most prevalent and aggressive primary brain tumors, represent a diverse group of malignancies originating from glial cells. These tumors account for significant brain tumor-related morbidity and mortality, with higher incidence rates in North America and Europe compared to Asia and Africa. Genetic predispositions and environmental factors, particularly ionizing radiation, critically impact glioma risk. Epigenetics, particularly DNA methylation, plays a pivotal role in glioma research, with IDH-mutant gliomas showing aberrant methylation patterns contributing to tumorigenesis. Epigenetic clocks, biomarkers based on DNA methylation patterns predicting biological age, have revealed significant insights into aging and tumor development. Recent studies demonstrate accelerated epigenetic aging in gliomas, correlating with increased cancer risk and poorer outcomes. This review explores the mechanisms of epigenetic clocks, their biological significance, and their application in glioma research. Furthermore, the clinical implications of epigenetic clocks in diagnosing, prognosticating, and treating gliomas are discussed. The integration of epigenetic clock data into personalized medicine approaches holds promise for enhancing therapeutic strategies and patient outcomes in glioma treatment.

Adeno-associated virus delivered CXCL9 sensitizes glioblastoma to anti-PD-1 immune checkpoint blockade

There are numerous mechanisms by which glioblastoma cells evade immunological detection, underscoring the need for strategic combinatorial treatments to achieve appreciable therapeutic effects. However, developing combination therapies is difficult due to dose-limiting toxicities, blood-brain-barrier, and suppressive tumor microenvironment. Glioblastoma is notoriously devoid of lymphocytes driven in part by a paucity of lymphocyte trafficking factors necessary to prompt their recruitment and activation. Herein, we develop a recombinant adeno-associated virus (AAV) gene therapy that enables focal and stable reconstitution of the tumor microenvironment with C-X-C motif ligand 9 (CXCL9), a powerful call-and-receive chemokine for lymphocytes. By manipulating local chemokine directional guidance, AAV-CXCL9 increases tumor infiltration by cytotoxic lymphocytes, sensitizing glioblastoma to anti-PD-1 immune checkpoint blockade in female preclinical tumor models. These effects are accompanied by immunologic signatures evocative of an inflamed tumor microenvironment. These findings support AAV gene therapy as an adjuvant for reconditioning glioblastoma immunogenicity given its safety profile, tropism, modularity, and off-the-shelf capability.

An Update on the Clinical Status, Challenges, and Future Directions of Oncolytic Virotherapy for Malignant Gliomas

OPINION STATEMENT

Malignant gliomas are common central nervous system tumors that pose a significant clinical challenge due to the lack of effective treatments. Glioblastoma (GBM), a grade 4 malignant glioma, is the most prevalent primary malignant brain tumor and is associated with poor prognosis. Current clinical trials are exploring various strategies to combat GBM, with oncolytic viruses (OVs) appearing particularly promising. In addition to ongoing and recently completed clinical trials, one OV (Teserpaturev, Delytact®) received provisional approval for GBM treatment in Japan. OVs are designed to selectively target and eliminate cancer cells while promoting changes in the tumor microenvironment that can trigger and support long-lasting anti-tumor immunity. OVs offer the potential to remodel the tumor microenvironment and reverse systemic immune exhaustion. Additionally, an increasing number of OVs are armed with immunomodulatory payloads or combined with immunotherapy approaches in an effort to promote anti-tumor responses in a tumor-targeted manner. Recently completed oncolytic virotherapy trials can guide the way for future treatment individualization through patient preselection, enhancing the likelihood of achieving the highest possible clinical success. These trials also offer valuable insight into the numerous challenges inherent in malignant glioma treatment, some of which OVs can help overcome.

Generation of glioblastoma in mice engrafted with human cytomegalovirus-infected astrocytes

Mounting evidence is identifying human cytomegalovirus (HCMV) as a potential oncogenic virus. HCMV has been detected in glioblastoma multiforme (GB). Herewith, we present the first experimental evidence for the generation of CMV-Elicited Glioblastoma Cells (CEGBCs) possessing glioblastoma-like traits that lead to the formation of glioblastoma in orthotopically xenografted mice. In addition to the already reported oncogenic HCMV-DB strain, we isolated three HCMV clinical strains from GB tissues that transformed HAs toward CEGBCs and generated spheroids from CEGBCs that resulted in the appearance of glioblastoma-like tumors in xenografted mice. These tumors were nestin-positive mostly in the invasive part surrounded by GFAP-positive reactive astrocytes. The glioblastoma immunohistochemistry phenotype was confirmed by EGFR and cMet gene amplification in the tumor parallel to the detection of HCMV IE and UL69 genes and proteins. Our results fit with an HCMV-induced glioblastoma model of oncogenesis in vivo which will open the door to new therapeutic approaches and assess the anti-HCMV treatment as well as immunotherapy in fighting GB which is characterized by poor prognosis.

Synthesis and Characterization of a Novel PET Tracer for Noninvasive Evaluation of FGL1 Status in Tumors

Fibrinogen-like protein 1 (FGL1) is a potential novel immune checkpoint target for malignant tumor diagnosis and therapy. Accurate detection of FGL1 levels in tumors via noninvasive PET imaging might be beneficial for managing the disease. To achieve this, multiple FGL1-targeting peptides (FGLP) were designed, and a promising candidate, 68Ga-NOTA-FGLP2, was identified through a high-throughput screening approach using microPET imaging of 68Ga-labeled peptides. Subsequent in vitro cell experiments showed that uptake values of 68Ga-NOTA-FGLP2 in FGL1 positive Huh7 tumor cells were significantly higher than those in FGL1 negative U87 MG tumor cells. Further microPET imaging showed that the Huh7 xenografts were clearly visualized with a favorable contrast. ROI analysis showed that the uptake values of the tracer in Huh7 xenografts were 2.63 ± 0.07% ID/g at 30 min p.i.. After treatment with an excess of unlabeled FGLP2, the tumor uptake significantly decreased to 0.54 ± 0.05% ID/g at 30 min p.i.. Moreover, the uptake in U87 MG xenografts was 0.44 ± 0.06% ID/g at the same time point. The tracer was excreted mainly through the renal system. 18F-FDG PET imaging was also performed in mice bearing Huh7 and U87 MG xenografts, respectively. However, there was no significant difference in the uptake between the tumors with different FGL1 expressions. Preclinical data indicated that 68Ga-NOTA-FGLP2 might be a suitable radiotracer for in vivo noninvasive visualization of tumors with abundant expression of FGL1. Further investigation of 68Ga-NOTA-FGLP2 for tumor diagnosis and therapy is undergoing.

Modularized supramolecular assemblies for hypoxia-activatable fluorescent visualization and image-guided theranostics

Rationale: Molecular imaging of microenvironment by hypoxia-activatable fluorescence probes has emerged as an attractive approach to tumor diagnosis and image-guided treatment. Difficulties remain in its translational applications due to hypoxia heterogeneity in tumor microenvironments, making it challenging to image hypoxia as a reliable proxy of tumor distribution. Methods: We report a modularized theranostics platform to fluorescently visualize hypoxia via light-modulated signal compensation to overcome tumor heterogeneity, thereby serving as a diagnostic tool for image-guided surgical resection and photodynamic therapy. Specifically, the platform integrating dual modules of fluorescence indicator and photodynamic moderator using supramolecular host-guest self-assembly, which operates cooperatively as a cascaded "AND" logic gate. First, tumor enrichment and specific fluorescence turn-on in hypoxic regions were accessible via tumor receptors and cascaded microenvironment signals as simultaneous inputs of the "AND" gate. Second, image guidance by a lighted fluorescence module and light-mediated endogenous oxygen consumption of a photodynamic module as dual inputs of "AND" gate collaboratively enabled light-modulated signal compensation in situ, indicating homogeneity of enhanced hypoxia-related fluorescence signals throughout a tumor. Results: In in vitro and in vivo analyses, the biocompatible platform demonstrated several strengths including a capacity for dual tumor targeting to progressively facilitate specific fluorescence turn-on, selective signal compensation, imaging-time window extension conducive to precise normalized image-guided treatment, and the functionality of tumor glutathione depletion to improve photodynamic efficacy. Conclusion: The hypoxia-activatable, image-guided theranostic platform demonstrated excellent potential for overcoming hypoxia heterogeneity in tumors.

Overcoming Barriers in Glioblastoma-Advances in Drug Delivery Strategies

The world of cancer treatment is evolving rapidly and has improved the prospects of many cancer patients. Yet, there are still many cancers where treatment prospects have not (or hardly) improved. Glioblastoma is the most common malignant primary brain tumor, and even though it is sensitive to many chemotherapeutics when tested under laboratory conditions, its clinical prospects are still very poor. The blood-brain barrier (BBB) is considered at least partly responsible for the high failure rate of many promising treatment strategies. We describe the workings of the BBB during healthy conditions and within the glioblastoma environment. How the BBB acts as a barrier for therapeutic options is described as well as various approaches developed and tested for passing or opening the BBB, with the ultimate aim to allow access to brain tumors and improve patient perspectives.

Ultrasound-mediated delivery of doxorubicin to the brain results in immune modulation and improved responses to PD-1 blockade in gliomas

Given the marginal penetration of most drugs across the blood-brain barrier, the efficacy of various agents remains limited for glioblastoma (GBM). Here we employ low-intensity pulsed ultrasound (LIPU) and intravenously administered microbubbles (MB) to open the blood-brain barrier and increase the concentration of liposomal doxorubicin and PD-1 blocking antibodies (aPD-1). We report results on a cohort of 4 GBM patients and preclinical models treated with this approach. LIPU/MB increases the concentration of doxorubicin by 2-fold and 3.9-fold in the human and murine brains two days after sonication, respectively. Similarly, LIPU/MB-mediated blood-brain barrier disruption leads to a 6-fold and a 2-fold increase in aPD-1 concentrations in murine brains and peritumoral brain regions from GBM patients treated with pembrolizumab, respectively. Doxorubicin and aPD-1 delivered with LIPU/MB upregulate major histocompatibility complex (MHC) class I and II in tumor cells. Increased brain concentrations of doxorubicin achieved by LIPU/MB elicit IFN-γ and MHC class I expression in microglia and macrophages. Doxorubicin and aPD-1 delivered with LIPU/MB results in the long-term survival of most glioma-bearing mice, which rely on myeloid cells and lymphocytes for their efficacy. Overall, this translational study supports the utility of LIPU/MB to potentiate the antitumoral activities of doxorubicin and aPD-1 for GBM.

Extracellular vesicles in glioblastoma: a challenge and an opportunity

Glioblastoma is a highly heterogeneous tumor whose pathophysiological complexities dictate both the diagnosis of disease severity as well as response to therapy. Conventional diagnostic tools and standard treatment regimens have only managed to achieve limited success in the management of patients suspected of glioblastoma. Extracellular vesicles are an emerging liquid biopsy tool that has shown great promise in resolving the limitations presented by the heterogeneous nature of glioblastoma. Here we discuss the contrasting yet interdependent dual role of extracellular vesicles as communication agents that contribute to the progression of glioblastoma by creating a heterogeneous microenvironment and as a liquid biopsy tool providing an opportunity to accurately identify the disease severity and progression.

MCM5 is a Novel Therapeutic Target for Glioblastoma

Objective

MCM5 is a DNA licensing factor involved in cell proliferation and has been previously established as an excellent biomarker in a number of malignancies. Nevertheless, the role of MCM5 in GBM has not been fully clarified. The present study aimed to investigate the potential roles of MCM5 in the treatment of GBM and to elucidate its underlying mechanism, which is beneficial for developing new therapeutic strategies and predicting prognosis.

Methods

Firstly, we obtained transcriptomic and proteomic data from the TCGA and CPTAC databases on glioma patients. Employing the DeSeq2 R package, we then identified genes with joint differential expression in GBM tissues subjected to chemotherapy. To develop a prognostic risk score model, we performed univariate and multivariate Cox regression analyses. In vitro knockdown and overexpression of MCM5 were used to further investigate the biological functions of GBM cells. Additionally, we also delved into the upstream regulation of MCM5, revealing associations with several transcription factors. Finally, we investigated differences in immune cell infiltration and drug sensitivity across diverse risk groups identified in the prognostic risk model.

Results

In this study, the chemotherapy-treated GBM samples exhibited consistent alterations in 46 upregulated and 94 downregulated genes at both the mRNA and protein levels. Notably, MCM5 emerged as a gene with prognostic significance as well as potential therapeutic relevance. In vitro experiments subsequently validated the role of increased MCM5 expression in promoting GBM cell proliferation and resistance to TMZ. Correlations with transcription factors such as CREB1, CTCF, NFYB, NRF1, PBX1, TEAD1, and USF1 were discovered during upstream regulatory analysis, enriching our understanding of MCM5 regulatory mechanisms. The study additionally delves into immune cell infiltration and drug sensitivity, providing valuable insights for personalized treatment approaches.

Conclusion

This study identifies MCM5 as a key player in GBM, demonstrating its prognostic significance and potential therapeutic relevance by elucidating its role in promoting cell proliferation and resistance to chemotherapy.

Nanoparticles for efficient drug delivery and drug resistance in glioma: New perspectives

Gliomas are the most common primary tumors of the central nervous system, with glioblastoma multiforme (GBM) having the highest incidence, and their therapeutic efficacy depends primarily on the extent of surgical resection and the efficacy of postoperative chemotherapy. The role of the intracranial blood-brain barrier and the occurrence of the drug-resistant gene O6-methylguanine-DNA methyltransferase have greatly limited the efficacy of chemotherapeutic agents in patients with GBM and made it difficult to achieve the expected clinical response. In recent years, the rapid development of nanotechnology has brought new hope for the treatment of tumors. Nanoparticles (NPs) have shown great potential in tumor therapy due to their unique properties such as light, heat, electromagnetic effects, and passive targeting. Furthermore, NPs can effectively load chemotherapeutic drugs, significantly reduce the side effects of chemotherapeutic drugs, and improve chemotherapeutic efficacy, showing great potential in the chemotherapy of glioma. In this article, we reviewed the mechanisms of glioma drug resistance, the physicochemical properties of NPs, and recent advances in NPs in glioma chemotherapy resistance. We aimed to provide new perspectives on the clinical treatment of glioma.

Epigenetic regulation of tumor-immune symbiosis in glioma

Glioma is a type of aggressive and incurable brain tumor. Patients with glioma are highly resistant to all types of therapies, including immunotherapies. Epigenetic reprogramming is a key molecular hallmark in tumors across cancer types, including glioma. Mounting evidence highlights a pivotal role of epigenetic regulation in shaping tumor biology and therapeutic responses through mechanisms involving both glioma cells and immune cells, as well as their symbiotic interactions in the tumor microenvironment (TME). In this review, we discuss the molecular mechanisms of epigenetic regulation that impacts glioma cell biology and tumor immunity in both a cell-autonomous and non-cell-autonomous manner. Moreover, we provide an overview of potential therapeutic approaches that can disrupt epigenetic-regulated tumor-immune symbiosis in the glioma TME.

Tenacissoside H repressed the progression of glioblastoma by inhibiting the PI3K/Akt/mTOR signaling pathway

Glioblastoma (GBM) is one of the most common intracranial primary malignancies with the highest mortality rate, and there is a lack of effective treatments. In this study, we examined the anti-GBM activity of Tenacissoside H (TH), an active component isolated from the traditional Chinese medicine Marsdenia tenacissima (Roxb.) Wight & Arn (MT), and investigated the potential mechanism. Firstly, we found that TH decreased the viability of GBM cells by inducing cell cycle arrest and apoptosis, and inhibited the migration of GBM cells. Furthermore, combined with the Gene Expression Omnibus database (GEO) and network pharmacology as well as molecular docking, TH was shown to inhibit GBM progression by directly regulating the PI3K/Akt/mTOR pathway, which was further validated in vitro. In addition, the selective PI3K agonist 740 y-p partially restored the inhibitory effects of TH on GBM cells. Finally, TH inhibited GBM progression in an orthotopic transplantation model by inactivating the PI3K/Akt/mTOR pathway in vivo. Conclusively, our results suggest that TH represses GBM progression by inhibiting the PI3K/Akt/mTOR signaling pathway in vitro and in vivo, and provides new insight for the treatment of GBM patients.

Enhancing cancer immunotherapy with photodynamic therapy and nanoparticle: making tumor microenvironment hotter to make immunotherapeutic work better

Cancer immunotherapy has made tremendous advancements in treating various malignancies. The biggest hurdle to successful immunotherapy would be the immunosuppressive tumor microenvironment (TME) and low immunogenicity of cancer cells. To make immunotherapy successful, the 'cold' TME must be converted to 'hot' immunostimulatory status to activate residual host immune responses. To this end, the immunosuppressive equilibrium in TME should be broken, and immunogenic cancer cell death ought to be induced to stimulate tumor-killing immune cells appropriately. Photodynamic therapy (PDT) is an efficient way of inducing immunogenic cell death (ICD) of cancer cells and disrupting immune-restrictive tumor tissues. PDT would trigger a chain reaction that would make the TME 'hot' and have ICD-induced tumor antigens presented to immune cells. In principle, the strategic combination of PDT and immunotherapy would synergize to enhance therapeutic outcomes in many intractable tumors. Novel technologies employing nanocarriers were developed to deliver photosensitizers and immunotherapeutic to TME efficiently. New-generation nanomedicines have been developed for PDT immunotherapy in recent years, which will accelerate clinical applications.

Immunotherapeutic Strategies for the Treatment of Glioblastoma: Current Challenges and Future Perspectives

Despite decades of research and the best up-to-date treatments, grade 4 Glioblastoma (GBM) remains uniformly fatal with a patient median overall survival of less than 2 years. Recent advances in immunotherapy have reignited interest in utilizing immunological approaches to fight cancer. However, current immunotherapies have so far not met the anticipated expectations, achieving modest results in their journey from bench to bedside for the treatment of GBM. Understanding the intrinsic features of GBM is of crucial importance for the development of effective antitumoral strategies to improve patient life expectancy and conditions. In this review, we provide a comprehensive overview of the distinctive characteristics of GBM that significantly influence current conventional therapies and immune-based approaches. Moreover, we present an overview of the immunotherapeutic strategies currently undergoing clinical evaluation for GBM treatment, with a specific emphasis on those advancing to phase 3 clinical studies. These encompass immune checkpoint inhibitors, adoptive T cell therapies, vaccination strategies (i.e., RNA-, DNA-, and peptide-based vaccines), and virus-based approaches. Finally, we explore novel innovative strategies and future prospects in the field of immunotherapy for GBM.

Focused ultrasound-assisted delivery of immunomodulating agents in brain cancer

Focused ultrasound (FUS) combined with intravascularly circulating microbubbles can transiently increase the permeability of the blood-brain barrier (BBB) to enable targeted therapeutic delivery to the brain, the clinical testing of which is currently underway in both adult and pediatric patients. Aside from traditional cancer drugs, this technique is being extended to promote the delivery of immunomodulating therapeutics to the brain, including antibodies, immune cells, and cytokines. In this manner, FUS approaches are being explored as a tool to improve and amplify the effectiveness of immunotherapy for both primary and metastatic brain cancer, a particularly challenging solid tumor to treat. Here, we present an overview of the latest groundbreaking research in FUS-assisted delivery of immunomodulating agents to the brain in pre-clinical models of brain cancer, and place it within the context of the current immunotherapy approaches. We follow this up with a discussion on new developments and emerging strategies for this rapidly evolving approach.

Impact of tissue-agnostic approvals on management of primary brain tumors

Novel tissue-agnostic therapeutics targeting driver mutations in tumor cells have been recently approved by FDA, driven by basket trials that have demonstrated their efficacy and safety across diverse tumor histology. However, the relative rarity of primary brain tumors (PBTs) has limited their representation in early trials of tissue-agnostic medications. Thus, consensus continues to evolve regarding utility of tissue-agnostic medications in routine practice for PBTs, a diverse group of neoplasms characterized by limited treatment options and unfavorable prognoses. We describe current and potential impact of tissue-agnostic approvals on management of PBTs. We discuss data from clinical trials for PBTs regarding tissue-agnostic targets, including BRAFV600E, neurotrophic tyrosine receptor kinase (NTRK) fusions, microsatellite instability-high (MSI-High), mismatch repair deficiency (dMMR), and high tumor mutational burden (TMB-H), in context of challenges in managing PBTs. Described are additional tissue-agnostic targets that hold promise for benefiting patients with PBTs, including RET fusion, fibroblast growth factor receptor (FGFR), ERBB2/HER2, and KRASG12C, and TP53Y220C.

Multimodal neuro-nanotechnology: Challenging the existing paradigm in glioblastoma therapy

Integrating multimodal neuro- and nanotechnology-enabled precision immunotherapies with extant systemic immunotherapies may finally provide a significant breakthrough for combatting glioblastoma (GBM). The potency of this approach lies in its ability to train the immune system to efficiently identify and eradicate cancer cells, thereby creating anti-tumor immune memory while minimizing multi-mechanistic immune suppression. A critical aspect of these therapies is the controlled, spatiotemporal delivery of structurally defined nanotherapeutics into the GBM tumor microenvironment (TME). Architectures such as spherical nucleic acids or poly(beta-amino ester)/dendrimer-based nanoparticles have shown promising results in preclinical models due to their multivalency and abilities to activate antigen-presenting cells and prime antigen-specific T cells. These nanostructures also permit systematic variation to optimize their distribution, TME accumulation, cellular uptake, and overall immunostimulatory effects. Delving deeper into the relationships between nanotherapeutic structures and their performance will accelerate nano-drug development and pave the way for the rapid clinical translation of advanced nanomedicines. In addition, the efficacy of nanotechnology-based immunotherapies may be enhanced when integrated with emerging precision surgical techniques, such as laser interstitial thermal therapy, and when combined with systemic immunotherapies, particularly inhibitors of immune-mediated checkpoints and immunosuppressive adenosine signaling. In this perspective, we highlight the potential of emerging treatment modalities, combining advances in biomedical engineering and neurotechnology development with existing immunotherapies to overcome treatment resistance and transform the management of GBM. We conclude with a call to action for researchers to leverage these technologies and accelerate their translation into the clinic.

The need for paradigm shift: prognostic significance and implications of standard therapy-related systemic immunosuppression in glioblastoma for immunotherapy and oncolytic virotherapy

Despite significant advances in our knowledge regarding the genetics and molecular biology of gliomas over the past two decades and hundreds of clinical trials, no effective therapeutic approach has been identified for adult patients with newly diagnosed glioblastoma, and overall survival remains dismal. Great hopes are now placed on combination immunotherapy. In clinical trials, immunotherapeutics are generally tested after standard therapy (radiation, temozolomide, and steroid dexamethasone) or concurrently with temozolomide and/or steroids. Only a minor subset of patients with progressive/recurrent glioblastoma have benefited from immunotherapies. In this review, we comprehensively discuss standard therapy-related systemic immunosuppression and lymphopenia, their prognostic significance, and the implications for immunotherapy/oncolytic virotherapy. The effectiveness of immunotherapy and oncolytic virotherapy (viro-immunotherapy) critically depends on the activity of the host immune cells. The absolute counts, ratios, and functional states of different circulating and tumor-infiltrating immune cell subsets determine the net immune fitness of patients with cancer and may have various effects on tumor progression, therapeutic response, and survival outcomes. Although different immunosuppressive mechanisms operate in patients with glioblastoma/gliomas at presentation, the immunological competence of patients may be significantly compromised by standard therapy, exacerbating tumor-related systemic immunosuppression. Standard therapy affects diverse immune cell subsets, including dendritic, CD4+, CD8+, natural killer (NK), NKT, macrophage, neutrophil, and myeloid-derived suppressor cell (MDSC). Systemic immunosuppression and lymphopenia limit the immune system's ability to target glioblastoma. Changes in the standard therapy are required to increase the success of immunotherapies. Steroid use, high neutrophil-to-lymphocyte ratio (NLR), and low post-treatment total lymphocyte count (TLC) are significant prognostic factors for shorter survival in patients with glioblastoma in retrospective studies; however, these clinically relevant variables are rarely reported and correlated with response and survival in immunotherapy studies (e.g., immune checkpoint inhibitors, vaccines, and oncolytic viruses). Our analysis should help in the development of a more rational clinical trial design and decision-making regarding the treatment to potentially improve the efficacy of immunotherapy or oncolytic virotherapy.

CD8+CD103+PD1+TIM3+ T cells in glioblastoma microenvironment correlate with prognosis

Glioblastoma, isocitrate dehydrogenase-wildtype (GB), is the most common and aggressive primary brain malignancy with poor outcome. Immune checkpoint inhibitors (ICIs) have been tested in GB and, despite disappointing results, the identification of a small subgroup of responders underlies the need to improve our understanding of the tumour microenvironment (TME) immunity. This study aimed to determine whether the expression of selected immune checkpoints on tissue-resident memory T cells (Trm) may predict patient outcome. We conducted a single cohort observational study. Tumour samples were collected from 45 patients with histologically confirmed GB (WHO grade 4) and processed to obtain single-cell suspensions. Patients were assessed for the correlation of Trm phenotype with overall survival (OS) or progression-free survival (PFS) using multiparametric flow cytometry and uni/multivariate analyses. Levels of Trm expressing programmed cell death protein 1 (PD1) and T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) were found to be linked to clinical outcome. Low frequency of Trm expressing PD1 or TIM3 or both markers defined subgroups as independent positive prognostic factors for patient survival. On multivariate analysis, low CD8+CD103+PD1+TIM3+ Trm and Karnofsky performance status (KPS) ≥70 were confirmed to be the most predictive independent factors associated with longer OS (hazard ratios-HR [95%CI]: 0.14 [0.04-0.52] p < 0.001, 0.39 [0.16-0.96] p = 0.04, respectively). The CD8+CD103+ Trm subgroups were also age-related predictors for survival in GB.

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

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

RUNX1/NPM1/H3K4me3 complex contributes to extracellular matrix remodeling via enhancing FOSL2 transcriptional activation in glioblastoma

Extracellular matrix (ECM) remodeling has been implicated in the tumor malignant progression and immune escape in glioblastoma (GBM). Runt-related transcription factor 1 (RUNX1) is a vital transcriptional factor for promoting tumorigenesis and invasion in mesenchymal subtype of GBM. But the correlation between RUNX1 and ECM genes expression and regulatory mechanism of RUNX1 on ECM genes expression remain poorly understood to date. In this study, by using integral analysis of chromatin immunoprecipitation-sequencing and RNA sequencing, we reported that RUNX1 positively regulated the expression of various ECM-related genes, including Fibronectin 1 (FN1), Collagen type IV alpha 1 chain (COL4A1), and Lumican (LUM), in GBM. Mechanistically, we demonstrated that RUNX1 interacted with Nucleophosmin 1 (NPM1) to maintain the chromatin accessibility and facilitate FOS Like 2, AP-1 Transcription Factor Subunit (FOSL2)-mediated transcriptional activation of ECM-related genes, which was independent of RUNX1's transcriptional function. ECM remodeling driven by RUNX1 promoted immunosuppressive microenvironment in GBM. In conclusion, this study provides a novel mechanism of RUNX1 binding to NPM1 in driving the ECM remodeling and GBM progression.

Small Molecule Immunomodulators as Next-Generation Therapeutics for Glioblastoma

Glioblastoma (GBM), the most aggressive astrocytic glioma, remains a therapeutic challenge despite multimodal approaches. Immunotherapy holds promise, but its efficacy is hindered by the highly immunosuppressive GBM microenvironment. This review underscores the urgent need to comprehend the intricate interactions between glioma and immune cells, shaping the immunosuppressive tumor microenvironment (TME) in GBM. Immunotherapeutic advancements have shown limited success, prompting exploration of immunomodulatory approaches targeting tumor-associated macrophages (TAMs) and microglia, constituting a substantial portion of the GBM TME. Converting protumor M2-like TAMs to antitumor M1-like phenotypes emerges as a potential therapeutic strategy for GBM. The blood-brain barrier (BBB) poses an additional challenge to successful immunotherapy, restricting drug delivery to GBM TME. Research efforts to enhance BBB permeability have mainly focused on small molecules, which can traverse the BBB more effectively than biologics. Despite over 200 clinical trials for GBM, studies on small molecule immunomodulators within the GBM TME are scarce. Developing small molecules with optimal brain penetration and selectivity against immunomodulatory pathways presents a promising avenue for combination therapies in GBM. This comprehensive review discusses various immunomodulatory pathways in GBM progression with a focus on immune checkpoints and TAM-related targets. The exploration of such molecules, with the capacity to selectively target key immunomodulatory pathways and penetrate the BBB, holds the key to unlocking new combination therapy approaches for GBM.

ERK1/2 Phosphorylation Predicts Survival in Recurrent Glioblastoma Following Intracerebral and Adjuvant PD-1/CTLA-4 Immunotherapy: A REMARK-guided Analysis

PURPOSE

Evidence suggests that MAPK pathway activation, as measured by ERK1/2 phosphorylation (p-ERK), predicts overall survival (OS) in patients with recurrent glioblastoma receiving anti-PD-1 therapy. We aimed to validate these findings in independent cohorts.

EXPERIMENTAL DESIGN

In a 24-patient clinical trial on recurrent glioblastoma and high-grade gliomas, we examined the link between p-ERK levels and OS. Patients received intravenous nivolumab, followed by maximal safe resection and an intracerebral injection of either ipilimumab alone or combined with nivolumab. Biweekly adjuvant nivolumab was then administered up to five times (NCT03233152). Using REporting recommendations for tumor MARKER prognostic studies (REMARK) criteria, we conducted independent analyses for p-ERK quantification and statistical evaluations. Additional comparative analysis included prior cohorts, totaling 65 patients. Cox proportional hazards models and meta-analysis were employed to assess p-ERK as a predictive biomarker after immunotherapy.

RESULTS

Lower median p-ERK+ cell density was observed compared with prior studies, likely due to variable tissue processing across cohorts. Nonetheless, high p-ERK was associated with prolonged OS, particularly in isocitrate dehydrogenase wild-type glioblastomas (P = 0.036). Median OS for high and low p-ERK patients were 55.6 and 30 weeks, respectively. Multivariable analysis reinforced p-ERK's significance in survival prediction (P = 0.011). Upon p-ERK normalization across cohorts (n = 65), meta-analysis supported the survival benefit of elevated tumor p-ERK levels (P = 0.0424).

CONCLUSIONS

This study strengthens the role of p-ERK as a predictive biomarker for OS in patients with glioblastoma on immune checkpoint blockade. Future research should focus on further validation in prospective trials and the standardization of preanalytical variables influencing p-ERK quantification.

Glioma-Immune Cell Crosstalk in Tumor Progression

Glioma progression is a complex process controlled by molecular factors that coordinate the crosstalk between tumor cells and components of the tumor microenvironment (TME). Among these, immune cells play a critical role in cancer survival and progression. The complex interplay between cancer cells and the immune TME influences the outcome of immunotherapy and other anti-cancer therapies. Here, we present an updated view of the pro- and anti-tumor activities of the main myeloid and lymphocyte cell populations in the glioma TME. We review the underlying mechanisms involved in crosstalk between cancer cells and immune cells that enable gliomas to evade the immune system and co-opt these cells for tumor growth. Lastly, we discuss the current and experimental therapeutic options being developed to revert the immunosuppressive activity of the glioma TME. Knowledge of the complex interplay that elapses between tumor and immune cells may help develop new combination treatments able to overcome tumor immune evasion mechanisms and enhance response to immunotherapies.

'Slicing' glioblastoma drivers with the Swiss cheese model

The Swiss cheese model is used to assess risks and explain accidents in a variety of industries. This model can be applied to dissect the homeostatic mechanisms whose cumulative dysregulation contributes to disease states, including cancer. Using glioblastoma (GBM) as an exemplar, we discuss how specific protumorigenic mechanisms collectively drive disease by affecting genomic integrity, epigenetic regulation, metabolic homeostasis, and antitumor immunity. We further highlight how host factors, such as hormonal differences and aging, impact this process, and the interplay between these 'system failures' that enable tumor progression and foster therapeutic resistance. Finally, we examine therapies that consider the interactions between these elements, which may comprise more effective approaches given the multifaceted protumorigenic mechanisms that drive GBM.

Cancer vaccines in the clinic

Vaccines are an important tool in the rapidly evolving repertoire of immunotherapies in oncology. Although cancer vaccines have been investigated for over 30 years, very few have achieved meaningful clinical success. However, recent advances in areas such antigen identification, formulation development and manufacturing, combination therapy regimens, and indication and patient selection hold promise to reinvigorate the field. Here, we provide a timely update on the clinical status of cancer vaccines. We identify and critically analyze 360 active trials of cancer vaccines according to delivery vehicle, antigen type, indication, and other metrics, as well as highlight eight globally approved products. Finally, we discuss current limitations and future applications for clinical translation of cancer vaccines.

Identification of efferocytosis-related subtypes in gliomas and elucidating their characteristics and clinical significance

Introduction: Gliomas, the most prevalent tumors of the central nervous system, are known for their aggressive nature and poor prognosis. The heterogeneity among gliomas leads to varying responses to the same treatments, even among similar glioma types. In our study, we efferocytosis-related subtypes and explored their characteristics in terms of immune landscape, intercellular communication, and metabolic processes, ultimately elucidating their potential clinical implications. Methods and Results: We first identified efferocytosis-related subtypes in Bulk RNA-seq using the NMF algorithm. We then preliminarily demonstrated the correlation of these subtypes with efferocytosis by examining enrichment scores of cell death pathways, macrophage infiltration, and the expression of immune ligands. Our analysis of single-cell RNA-seq data further supported the association of these subtypes with efferocytosis. Through enrichment analysis, we found that efferocytosis-related subtypes differ from other types of gliomas in terms of immune landscape, intercellular communication, and substance metabolism. Moreover, we found that the efferocytosis-related classification is a prognostic factor with robust predictive performance by calculating the AUC values. We also found that efferocytosis-related subtypes, when compared with other gliomas in drug sensitivity, survival, and TIDE scores, show a clear link to the effectiveness of chemotherapy, radiotherapy, and immunotherapy in glioma patients. Discussion: We identified efferocytosis-related subtypes in gliomas by analyzing the expression of 137 efferocytosis-associated genes, exploring their characteristics in immune landscape, intercellular communication, metabolic processes, and genomic variations. Moreover, we discovered that the classification of efferocytosis-related subtypes has a strong prognostic predictive power and holds potential significance in guiding clinical treatment.

Association between brain cancer immunogenetic profile and in silico immunogenicities of 11 viruses

Several viruses including human herpes viruses (HHVs), human polyomavirus JCV, and human papilloma virus (HPV) have been implicated in brain cancer, albeit inconsistently. Since human leukocyte antigen (HLA) is centrally involved in the human immune response to viruses and has been implicated in brain cancer, we evaluated in silico the immunogenicity between 69 Class I HLA alleles with epitopes of proteins of 9 HHVs, JCV, and HPV with respect to a population-based HLA-brain cancer profile. We found that immunogenicity varied widely across HLA alleles with HLA-C alleles exhibiting the highest immunogenicity, and that immunogenicity scores were negatively associated with the population-based HLA-brain cancer profile, particularly for JCV, HHV6A, HHV5, HHV3, HHV8, and HHV7. Consistent with the role of HLA in foreign antigen elimination, the findings suggest that viruses with proteins of high HLA immunogenicity are eliminated more effectively and, consequently, less likely to cause brain cancer; conversely, the absence of highly immunogenic HLA may allow the viral antigens to persist, contributing to cancer.

Unexpected Transient Glioblastoma Regression in a Patient Previously Treated with Bacillus Calmette-Guérin Therapy: A Case Report and Immunomodulatory Effects Hypothesis

(1) Background: Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with limited treatment options and poor prognosis. Bacillus Calmette-Guérin (BCG), a live attenuated strain of Mycobacterium bovis, has been used as an immunotherapeutic agent in bladder cancer and has shown non-specific beneficial effects. This report presents a unique case of GBM regression following BCG therapy for bladder cancer, suggesting the potential systemic immunomodulatory effects of BCG on GBM. (2) Case Presentation: A 67-year-old male with a history of bladder cancer treated with BCG presented with neurological symptoms. Imaging revealed two GBM lesions, and surgery was performed to remove one. Subsequently, the patient experienced complete tumor regression after initial stability. (3) Conclusions: This case highlights the potential of BCG or other immunotherapies in GBM treatment and underscores the need for further research. Understanding the immunomodulatory effects of BCG on GBM could lead to innovative therapies for this devastating disease; although, overcoming the immune evasion mechanisms in the brain is a significant challenge. Further investigation is warranted to explore this promising avenue of research.

Advancing personalized medicine in brain cancer: exploring the role of mRNA vaccines

Advancing personalized medicine in brain cancer relies on innovative strategies, with mRNA vaccines emerging as a promising avenue. While the initial use of mRNA vaccines was in oncology, their stunning success in COVID-19 resulted in widespread attention, both positive and negative. Regardless of politically biased opinions, which relate more to the antigenic source than form of delivery, we feel it is important to objectively review this modality as relates to brain cancer. This class of vaccines trigger robust immune responses through MHC-I and MHC-II pathways, in both prophylactic and therapeutic settings. The mRNA platform offers advantages of rapid development, high potency, cost-effectiveness, and safety. This review provides an overview of mRNA vaccine delivery technologies, tumor antigen identification, combination therapies, and recent therapeutic outcomes, with a particular focus on brain cancer. Combinatorial approaches are vital to maximizing mRNA cancer vaccine efficacy, with ongoing clinical trials exploring combinations with adjuvants and checkpoint inhibitors and even adoptive cell therapy. Efficient delivery, neoantigen identification, preclinical studies, and clinical trial results are highlighted, underscoring mRNA vaccines' potential in advancing personalized medicine for brain cancer. Synergistic combinatorial therapies play a crucial role, emphasizing the need for continued research and collaboration in this area.

CXCL9 recombinant adeno-associated virus (AAV) virotherapy sensitizes glioblastoma (GBM) to anti-PD-1 immune checkpoint blockade

The promise of immunotherapy to induce long-term durable responses in conventionally treatment resistant tumors like glioblastoma (GBM) has given hope for patients with a dismal prognosis. Yet, few patients have demonstrated a significant survival benefit despite multiple clinical trials designed to invigorate immune recognition and tumor eradication. Insights gathered over the last two decades have revealed numerous mechanisms by which glioma cells resist conventional therapy and evade immunological detection, underscoring the need for strategic combinatorial treatments as necessary to achieve appreciable therapeutic effects. However, new combination therapies are inherently difficult to develop as a result of dose-limiting toxicities, the constraints of the blood-brain barrier, and the suppressive nature of the GBM tumor microenvironment (TME). GBM is notoriously devoid of lymphocytes driven in part by a paucity of lymphocyte trafficking factors necessary to prompt their recruitment, infiltration, and activation. We have developed a novel recombinant adeno-associated virus (AAV) gene therapy strategy that enables focal and stable reconstitution of the GBM TME with C-X-C motif ligand 9 (CXCL9), a powerful call-and-receive chemokine for cytotoxic T lymphocytes (CTLs). By precisely manipulating local chemokine directional guidance, AAV-CXCL9 increases tumor infiltration by CD8-postive cytotoxic lymphocytes, sensitizing GBM to anti-PD-1 immune checkpoint blockade (ICB). These effects are accompanied by immunologic signatures evocative of an inflamed and responsive TME. These findings support targeted AAV gene therapy as a promising adjuvant strategy for reconditioning GBM immunogenicity given its excellent safety profile, TME-tropism, modularity, and off-the-shelf capability, where focal delivery bypasses the constrains of the blood-brain barrier, further mitigating risks observed with high-dose systemic therapy.

The Role of Antibody-Based Therapies in Neuro-Oncology

This review explores the evolving landscape of antibody-based therapies in neuro-oncology, in particular, immune checkpoint inhibitors and immunomodulatory antibodies. We discuss their mechanisms of action, blood-brain barrier (BBB) penetration, and experience in neuro-oncological conditions. Evidence from recent trials indicates that while these therapies can modulate the tumor immune microenvironment, their clinical benefits remain uncertain, largely due to challenges with BBB penetration and tumor-derived immunosuppression. This review also examines emerging targets such as TIGIT and LAG3, the potential of antibodies in modulating the myeloid compartment, and tumor-specific targets for monoclonal antibody therapy. We further delve into advanced strategies such as antibody-drug conjugates and bispecific T cell engagers. Lastly, we explore innovative techniques being investigated to enhance antibody delivery, including CAR T cell therapy. Despite current limitations, these therapies hold significant therapeutic potential for neuro-oncology. Future research should focus on optimizing antibody delivery to the CNS, identifying novel biological targets, and discovering combination therapies to address the hostile tumor microenvironment.

Therapeutic cell-based vaccines for glioblastoma multiforme

Glioblastoma multiforme (GBM), a highly aggressive tumor, poses significant challenges in achieving successful treatment outcomes. Conventional therapeutic modalities including surgery, radiation, and chemotherapy have demonstrated limited efficacy, primarily attributed to the complexities associated with drug delivery to the tumor site and tumor heterogeneity. To address this critical need for innovative therapies, the potential of cancer vaccines utilizing tumor cells and dendritic cells has been explored for GBM treatment. This article provides a comprehensive review of therapeutic vaccinations employing cell-based vaccine strategies for the management of GBM. A meticulous evaluation of 45 clinical trials involving more than 1500 participants revealed that cell-based vaccinations have exhibited favorable safety profiles with minimal toxicity. Moreover, these vaccines have demonstrated modest improvements in overall survival and progression-free survival among patients. However, certain limitations still persist. Notably, there is a need for advancements in the development of potent antigens to evoke immune responses, as well as the optimization of dosage regimens. Consequently, while cell-based vaccinations show promise as a potential therapeutic approach for GBM, further research is imperative to overcome the current limitations. The ultimate objective is to surmount these obstacles and establish cell-based vaccinations as a standard therapeutic modality for GBM.

Methods behind oncolytic virus-based DC vaccines in cancer: Toward a multiphase combined treatment strategy for Glioblastoma (GBM) patients

Glioblastoma (GBM) remains an orphan cancer disease with poor outcome. Novel treatment strategies are needed. Immunotherapy has several modes of action. The addition of active specific immunotherapy with dendritic cell vaccines resulted in improved overall survival of patients. Integration of DC vaccination within the first-line combined treatment became a challenge, and immunogenic cell death immunotherapy during chemotherapy was introduced. We used a retrospective analysis using real world data to evaluate the complex combined treatment, which included individualized multimodal immunotherapy during and after standard of care, and which required adaptations during treatment, and found a further improvement of overall survival. We also discuss the use of real world data as evidence. Novel strategies to move the field of individualized multimodal immunotherapy forward for GBM patients are reviewed.

Genetic predisposition to altered blood cell homeostasis is associated with glioma risk and survival

Glioma is a highly fatal brain tumor comprised of molecular subtypes with distinct clinical trajectories. Observational studies have suggested that variability in immune response may play a role in glioma etiology. However, their findings have been inconsistent and susceptible to reverse causation due to treatment effects and the immunosuppressive nature of glioma. We applied genetic variants associated (p<5×10-8) with blood cell traits to a meta-analysis of 3418 glioma cases and 8156 controls. Genetically predicted increase in the platelet to lymphocyte ratio (PLR) was associated with an increased risk of glioma (odds ratio (OR)=1.25, p=0.005), especially in IDH-mutant (IDHmut OR=1.38, p=0.007) and IDHmut 1p/19q non-codeleted (IDHmut-noncodel OR=1.53, p=0.004) tumors. However, reduced glioma risk was observed for higher counts of lymphocytes (IDHmut-noncodel OR=0.70, p=0.004) and neutrophils (IDHmut OR=0.69, p=0.019; IDHmut-noncodel OR=0.60, p=0.009), which may reflect genetic predisposition to enhanced immune-surveillance. In contrast to susceptibility, there was no association with survival in IDHmut-noncodel; however, in IDHmut 1p/19q co-deleted tumors, we observed higher mortality with increasing genetically predicted counts of lymphocytes (hazard ratio (HR)=1.65, 95% CI: 1.24-2.20), neutrophils (HR=1.49, 1.13-1.97), and eosinophils (HR=1.59, 1.18-2.14). Polygenic scores for blood cell traits were also associated with tumor immune microenvironment features, with heterogeneity by IDH status observed for 17 signatures related to interferon signaling, PD-1 expression, and T-cell/Cytotoxic responses. In summary, we identified novel, immune-mediated susceptibility mechanisms for glioma with potential disease management implications.