Glioblastoma-infiltrated innate immune cells resemble M0 macrophage phenotype

Dynamics of inflammatory signals within the tumor microenvironment

Tumor stroma, or tumor microenvironment (TME), has been in the spotlight during recent years for its role in tumor development, growth, and metastasis. It consists of a myriad of elements, including tumor-associated macrophages, cancer-associated fibroblasts, a deregulated extracellular matrix, endothelial cells, and vascular vessels. The release of proinflammatory molecules, due to the inflamed microenvironment, such as cytokines and chemokines is found to play a pivotal role in progression of cancer and response to therapy. This review discusses the major key players and important chemical inflammatory signals released in the TME. Furthermore, the latest breakthroughs in cytokine-mediated crosstalk between immune cells and cancer cells have been highlighted. In addition, recent updates on alterations in cytokine signaling between chronic inflammation and malignant TME have also been reviewed.

High ELK3 expression is associated with the wild type IDH1 in glioma and enhances infiltration of M2 macrophages

BACKGROUND

The ETS transcription factor ELK3 has been identified as a novel oncogene that plays a significant role in the pathological processes and progression of various human cancers. Recent research indicates that ELK3 may serve as a potential prognostic molecular marker for glioma; however, its mechanistic role in glioma remains insufficiently explored.

PURPOSE

This study aimed to investigate the impact of ELK3 on glioma prognosis, examine the regulatory influence of IDH1 on ELK3, and assess the role of ELK3 in tumor immune infiltration.

METHODS

Bioinformatics techniques were employed to identify the gene ELK3, which exhibited significant differential expression and was associated with grading and prognosis in the public database. This finding was validated through immunohistochemistry and RT-qPCR, while the association between ELK3 expression and IDH1 status was confirmed using Western blotting and IHC. Furthermore, ELK3 expression demonstrated a positive correlation with the infiltration of M2 macrophages, as evidenced by immune co-culture studies.

RESULTS

The study identified ELK3 as significantly differentially expressed and associated with tumor grading and prognosis through analyses of public databases. Univariate and multivariate Cox proportional hazards regression analyses established ELK3 as an independent negative prognostic factor. Within The TCGA cohort, a prognostic nomogram was developed by integrating ELK3 with other clinical indicators, and its efficacy was evaluated using ROC curves and calibration curves. The nomogram demonstrated robust performance, with an AUC of no less than 0.9, and showed strong concordance in both internal and external validation cohorts. Furthermore, ELK3 expression was linked to the DNA methylation and mutation status of IDH1. Gene profiling related to ELK3 was constructed, revealing its potential biological functions in immunoregulatory processes through functional enrichment analysis. ELK3 expression exhibited a positive correlation with macrophage and neutrophil infiltration, consistent with findings from the TIMER and spatial transcriptomics. Additionally, ELK3 expression showed a moderate correlation with CD163 expression, suggesting its role in promoting immune infiltration involving M2 macrophages.

CONCLUSIONS

ELK3 is a potential prognostic marker for poor outcomes in diffuse glioma and may play a regulatory role in immune infiltration, particularly by enhancing M2 macrophage-mediated immune infiltration.

Exploring the tumor microenvironment in diffuse intrinsic pontine glioma: immunological insights and therapeutic challenges

Diffuse intrinsic pontine glioma (DIPG) is a rare and highly aggressive pediatric brain tumor with a median survival of less than 12 months. The tumor arises in the pons, making surgical resection unfeasible and limiting treatment options to palliative radiation, which offers minimal survival benefit. One of the major challenges in treating DIPG is the poorly understood tumor immune microenvironment, which has hindered the development of effective immunotherapies. DIPG tumors are considered to be immunologically cold with limited immune cell infiltration. Recent studies have begun to reveal the complex and heterogeneous immune landscape of DIPG, highlighting distinct immunological subgroups. This review aims to provide a comprehensive overview of the immune landscape of DIPG based on the latest insights, identify research gaps, and suggest potential areas for future investigation to improve treatment outcomes for patients with DIPG.

Dual blockade of GSTK1 and CD47 improves macrophage-mediated phagocytosis on cancer cells

CD47 is a crucial anti-phagocytic signal in regulating macrophage responses and its manipulation offers the therapeutic potential in cancer treatment. However, in many cases, blockade of CD47 by itself is insufficient to activate macrophage effectively, indicating other unidentified phagocytosis-regulating factors to resist the macrophage activity. In this study, a genome-wide human CRISPR-Cas9 library was developed for comprehensive screening of phagocytosis-regulating factors in the context of CD47 blockade. The screening results identified GSTK1 as a potential anti-phagocytic signal counteracting the efficacy of CD47-based phagocytosis. The disruption of GSTK1 significantly increased the phagocytosis rate of cancer cells by macrophages in combination with anti-CD47 antibody. Further mechanism investigation unveiled that GSTK1 blockade increased the membrane exposure of calreticulin in different cancer cells, which might be the primary mechanism driving enhanced macrophage-mediated phagocytosis. To this end, siGSTK1-loaded nanoparticles (siGSTK1-LNPs) were designed to suppress the GSTK1 expression efficiently. The comparable phagocytosis efficacy was also observed when combining siGSTK1-LNPs with anti-CD47 antibody. Above all, GSTK1 blockade was identified as a promising and feasible stimulus for enhancing the effectiveness of anti-CD47 antibody, introducing a novel and effective combination approach in cancer immunotherapy.

NLRP3 Inflammasome Activation Expands the Immunosuppressive Myeloid Stroma and Antagonizes the Therapeutic Benefit of STING Activation in Glioblastoma

Glioblastoma (GBM) is the most common and deadly primary brain malignancy and is clinically refractory to immunotherapy. Active NLRP3 inflammasome signaling and IL-1β secretion have been observed in GBM, and NLRP3-driven myeloid-derived suppressor cell (MDSC) recruitment can mediate cancer immune evasion. Agonists of the cytosolic double-stranded DNA-sensing stimulator of IFN gene (STING) pathway can mediate proinflammatory conversion of cancer MDSCs; however, secretion of the NLRP3 products IL-1β and IL-18 has also been observed in certain myeloid populations following STING activation. In this study, we aimed to determine both the potential mechanistic synergy between STING and NLRP3 agonists, and the effects of this innate immune combination on the GBM tumor immune landscape. We find that STING activation does not prime pro-IL-1β expression for activated NLRP3 inflammasome secretion. In subcutaneous GL261 GBM, we show that NLRP3 activation expands the immunosuppressive myeloid stroma primarily via granulocytic MDSC recruitment and antagonizes the benefit of STING activation. In brain GL261, we find that NLRP3 activation expands granulocytic MDSCs but does not antagonize the therapeutic benefit of STING activation. Finally, we report that mesenchymal subtype GBM tumors have elevated neutrophil, IL-1β, and NLRP3 gene expression, a setting where our data suggest that NLRP3 activation could counteract STING agonists.

SIGNIFICANCE

NLRP3 inflammasome signaling, which suppresses antitumor immunity in some cancers, has been observed in GBM tissues. NLRP3 activation in GBM induces granulocyte-dependent tumor immunosuppression and antagonizes the therapeutic efficacy of STING activation.

Spatial transcriptomics reveal high T cell and monocyte status as predictive and prognostic markers in pancreatic cancer

BACKGROUND

In the present study, we intended to discover predictive or prognostic factors of pancreatic ductal adenocarcinoma (PDAC). We intended to investigate the differences between PDAC cases that are treated with upfront surgery (UFS) and surgery after neoadjuvant FOLFIRINOX chemotherapy (NAT), and cases with good and poor responses to NAT, using digital spatial profiling (DSP) and immunohistochemical (IHC) analysis.

METHODS

Forty-eight PDAC cases that were surgically resected with or without NAT were included. A tissue microarray was constructed for DSP and IHC. Pathological tumor regression to NAT was graded based on the College of American Pathologists (CAP) system.

RESULTS

Between the UFS and NAT groups, there were no significant differentially expressed genes in all cell types. In the NAT group, MFAP4 and EGR3 were upregulated in CAP 2 in pan CK- and CD45-negative cells. Gene set enrichment analysis of CD45-positive cells showed that genes related to B or T cell-associated pathways were enriched in CAP 2, which correlated with the IHC; higher CD3-, CD4-, and CD8-positive cell densities in CAP 2. Multivariate analysis revealed age, high monocyte infiltration, and high CD68-positive cell infiltration as independent prognostic factors for overall survival.

CONCLUSIONS

Increased expression of MFAP4 and EGR3 as well as high CD3-, CD4-, and CD8-positive cell infiltration may be predictive markers of the NAT response in PDAC. Additionally, high monocyte infiltration and high CD68-positive cell infiltration could serve as prognostic markers for PDAC.

The Basis for Targeting the Tumor Macrophage Compartment in Glioblastoma Immunotherapy

Background: Glioblastoma (GBM) remains the most aggressive primary brain tumor with limited treatment options. The immunosuppressive tumor microenvironment (TME), largely shaped by tumor-associated macrophages (TAMs), represents a significant barrier to effective immunotherapy. Objective: This review aims to explore the role of TAMs within the TME, highlighting the phenotypic plasticity, interactions with tumor cells, and potential therapeutic targets to enhance anti-tumor immunity. Findings: TAMs constitute a substantial portion of the TME, displaying functional plasticity between immunosuppressive and pro-inflammatory phenotypes. Strategies targeting TAMs include depletion, reprogramming, and inhibition of pro-tumor signaling pathways. Preclinical studies show that modifying TAM behavior can shift the TME towards a pro-inflammatory state, enhancing antitumor immune responses. Clinical trials investigating inhibitors of TAM recruitment, polarization, and downstream signaling pathways reveal promising yet limited results, necessitating further research to optimize approaches. Conclusions: Therapeutic strategics targeting TAM plasticity through selective depletion, phenotypic reprogramming, or modulation of downstream immunosuppressive signals represent promising avenues to overcome GBM-associated immunosuppression. Early clinical trials underscore their safety and feasibility, yet achieving meaningful clinical efficacy requires deeper mechanistic understanding and combinatorial approaches integrating macrophage-direct therapies with existing immunotherapeutic modalities.

Exploring tumor-associated macrophages in glioblastoma: from diversity to therapy

Glioblastoma is the most aggressive and lethal cancer of the central nervous system, presenting substantial treatment challenges. The current standard treatment, which includes surgical resection followed by temozolomide and radiation, offers limited success. While immunotherapies, such as immune checkpoint inhibitors, have proven effective in other cancers, they have not demonstrated significant efficacy in GBM. Emerging research highlights the pivotal role of tumor-associated macrophages (TAMs) in supporting tumor growth, fostering treatment resistance, and shaping an immunosuppressive microenvironment. Preclinical studies show promising results for therapies targeting TAMs, suggesting potential in overcoming these barriers. TAMs consist of brain-resident microglia and bone marrow-derived macrophages, both exhibiting diverse phenotypes and functions within the tumor microenvironment. This review delves into the origin, heterogeneity, and functional roles of TAMs in GBM, underscoring their dual roles in tumor promotion and suppression. It also summarizes recent progress in TAM-targeted therapies, which may, in combination with other treatments like immunotherapy, pave the way for more effective and personalized strategies against this aggressive malignancy.

Reciprocal Modulation of Tumour and Immune Cell Motility: Uncovering Dynamic Interplays and Therapeutic Approaches

Dysregulated cell movement is a hallmark of cancer progression and metastasis, the leading cause of cancer-related mortality. The metastatic cascade involves tumour cell migration, invasion, intravasation, dissemination, and colonisation of distant organs. These processes are influenced by reciprocal interactions between cancer cells and the tumour microenvironment (TME), including immune cells, stromal components, and extracellular matrix proteins. The epithelial-mesenchymal transition (EMT) plays a crucial role in providing cancer cells with invasive and stem-like properties, promoting dissemination and resistance to apoptosis. Conversely, the mesenchymal-epithelial transition (MET) facilitates metastatic colonisation and tumour re-initiation. Immune cells within the TME contribute to either anti-tumour response or immune evasion. These cells secrete cytokines, chemokines, and growth factors that shape the immune landscape and influence responses to immunotherapy. Notably, immune checkpoint blockade (ICB) has transformed cancer treatment, yet its efficacy is often dictated by the immune composition of the tumour site. Elucidating the molecular cross-talk between immune and cancer cells, identifying predictive biomarkers for ICB response, and developing strategies to convert cold tumours into immune-active environments is critical to overcoming resistance to immunotherapy and improving patient survival.

7aaRGD - a novel SPP1/integrin signaling-blocking peptide reverses immunosuppression and improves anti-PD-1 immunotherapy outcomes in experimental gliomas

BACKGROUND

Immune checkpoint inhibitors (ICIs) present clinical benefits in many cancer patients but invariably fail in glioblastoma (GBM), the most common and deadly primary brain tumor. The lack of ICIs efficacy in GBM is attributed to the accumulation of tumor-reprogrammed glioma-associated myeloid cells (GAMs) that create a "cold" immunosuppressive tumor microenvironment (TME), impeding the infiltration and activation of effector T cells. GBM-derived αvβ3/αvβ5-integrin ligands, including SPP1, were shown to mediate the emergence of GAMs. We hypothesized that a combination strategy aiming to block the reprogramming of GAMs using a synthetic 7aaRGD peptide that targets SPP1/integrin signaling might overcome resistance to ICIs and reinvigorate anti-tumor immunity.

METHODS

Matrigel invasion assay was used to test the efficacy of 7aaRGD in glioma-microglia co-cultures. We determined the impact of 7aaRGD, administered as a monotherapy or combined with PD-1 blockade, on tumor growth, GAMs accumulation and phenotypes, arginase-1 levels and neovasculature in experimental gliomas. The effects of treatments on the tumor immune landscape were dissected using multiparameter flow cytometry, immunocytochemistry, cytokine profiling and RNA-seq analysis of sorted GAMs followed by CITE-seq based data deconvolution.

RESULTS

7aaRGD efficiently blocked microglia-dependent invasion of human and mouse glioma cells in vitro. Intratumorally delivered 7aaRGD alone did not reduce tumor growth in orthotopic gliomas but prevented the emergence of immunosuppressive GAMs and led to normalization of peritumoral blood vessels. Combining 7aaRGD with anti-PD-1 antibody resulted in reduced tumor growth, with an increase in the number of proliferating, interferon-ɣ producing CD8+T cells and depletion of regulatory T cells. Transcriptomic profiles of myeloid cells were altered by the combined treatment, reflecting the restored "hot" inflammatory TME and boosted immunotherapy responses. Intratumoral administration of 7aaRGD similarly modified the phenotypes of GAMs in human U87-MG gliomas in immunocompromised mice. Exploration of transcriptomic datasets revealed that high expression of integrin receptor coding genes in pre-treatment biopsies was associated with a poorer response to immune check-point blockade in patients with several types of cancers.

CONCLUSIONS

We demonstrate that combining the blockade of SPP1/integrin signaling with ICIs modifies innate immunity and reinvigorates adaptive antitumor responses, which paves the way to improve immunotherapy outcomes in GBM.

MUC1 and MUC4 expression are inversely correlated and trigger immunological response and transport pathways in adult-type diffuse gliomas

Adult-type diffuse gliomas arise from glial or progenitor cells. These tumors are currently classified as astrocytoma isocitrate dehydrogenase (IDH)-mutant or IDH-mutant oligodendroglioma with co-deletion of chromosomal arms 1p and 19q, both of which could be either slow-growing tumors, or glioblastoma (GBM), which is a more aggressive tumor. Despite advances in diagnosis and treatment, the median survival time after GBM diagnosis remains low at approximately 15 months, with a 5-year overall survival (OS) rate of 6.8 %. Therefore, new biomarker and therapeutic target discoveries are required to improve prognosis. Mucin 1 (MUC1) and MUC4 are membrane-bound mucins and potential biomarkers of several tumors. However, the role of these mucins in adult gliomas has not been well explored. In this retrospective study, in silico analysis of data from patients with adult-type diffuse glioma revealed differential methylation and expression patterns of MUC1 and MUC4 between GBM and non-GBM groups. In the GBM group, decreased methylation and elevated expression of MUC1 were observed (r = -0.25, p < 0.0001), whereas increased methylation and decreased expression of MUC4 were observed (r = -0.13, p = 0.1344). Conversely, in the non-GBM group, MUC1 exhibited higher methylation and lower expression (r = -0.27, p < 0.0001), whereas MUC4 showed lower methylation and higher expression (r = -0.32, p < 0.0001). The expression of these genes influenced OS in adult patients with glioma (p = 0.0344), with high MUC1 and low MUC4 expression associated with worse OS. MUC1 and MUC4 expression correlated with that of MUC20 in both GBM (r = 0.54) and non-GBM (r = 0.53) groups (p < 0.0001). Functional enrichment analysis identified the biological roles of MUC1-co-expressed genes as involvement in innate immunity, antigen processing, and proinflammatory responses in both the non-GBM and GBM groups, and integrin-based signaling pathways in the GBM group. MUC4-co-expressed genes are involved in ion transport in GBM patients. Using molecular docking, we observed that MUC1 domains physically interact with immune response-related proteins, such as receptors for advanced glycation end products (RAGE), major histocompatibility complex II (MHC-II), and extracellular matrix receptor integrin alpha 2 (ITGA2). To our knowledge, this is the first retrospective study and in silico analysis demonstrating the relevance and correlation of MUC1 and MUC4 in adult gliomas. These findings elucidate the molecular mechanisms underlying adult-type diffuse glioma progression and highlight MUC1 and MUC4 as potential prognostic markers and therapeutic targets for glioma management.

Advancements in nanotheranostics for glioma therapy

Gliomas are brain tumors mainly derived from glial cells that are difficult to treat and cause high mortality. Radiation, chemotherapy, and surgical excision are the conventional treatments for gliomas. Patients who have surgery or have undergone chemotherapy for glioma treatment have poor prognosis with tumor recurrence. In particular, for glioblastoma, the 5-year average survival rate is 4-7%, and the median survival is 12-18 months. A number of issues hinder effective treatment such as, poor surgical resection, tumor heterogeneity, insufficient drug penetration across the blood-brain barrier, multidrug resistance, and difficulties with drug specificity. Nanotheranostic-mediated drug delivery is becoming a well-researched consideration, and an efficient non-invasive method for delivering chemotherapeutic drugs to the target area. Theranostic nanomedicines, which incorporate therapeutic drugs and imaging agents for personalized therapies, can be used for preventing overdose of non-responders. Through the identification of massive and complicated information from next-generation sequencing, machine learning enables for precise prediction of therapeutic outcomes and post-treatment management for patients with cancer. This article gives a thorough overview of nanocarrier-mediated drug delivery with a brief introduction to drug delivery challenges. In addition, this assessment offers a current summary of preclinical and clinical research on nanomedicines for gliomas. In the future, nanotheranostics will provide personalized treatment for gliomas and other treatable cancers.

Identification of potential diagnostic targets and therapeutic strategies for anoikis-related biomarkers in lung squamous cell carcinoma using machine learning and computational virtual screening

Objective

Lung squamous cell carcinoma (LUSC) is a common subtype of non-small cell lung cancer (NSCLC) characterized by high invasiveness, high metastatic potential, and drug resistance, resulting in poor patient prognosis. Anoikis, a specific form of apoptosis triggered by cell detachment from the extracellular matrix (ECM), plays a crucial role in tumor metastasis. Resistance to anoikis is a key mechanism by which cancer cells acquire metastatic potential. Although several studies have identified biomarkers related to LUSC, the role of anoikis-related genes (ARGs) remains largely unexplored.

Methods

Anoikis-related genes were obtained from the Harmonizome and GeneCards databases, and 222 differentially expressed genes (DEGs) in LUSC were identified via differential expression analysis. Univariate Cox regression analysis identified 74 ARGs significantly associated with survival, and a prognostic model comprising 8 ARGs was developed using LASSO and multivariate Cox regression analyses. The model was internally validated using receiver operating characteristic (ROC) curves and Kaplan-Meier (K-M) survival curves. Differences in immune cell infiltration and gene expression between high- and low-risk groups were analyzed. Virtual drug screening and molecular dynamics simulations were performed to evaluate the therapeutic potential of CSNK2A1, a key gene in the model. Finally, in vitro experiments were conducted to validate the therapeutic effects of the identified drug on LUSC.

Results

The 8-gene prognostic model demonstrated excellent predictive performance and stability. Significant differences in immune cell infiltration and immune microenvironment characteristics were observed between the high- and low-risk groups, suggesting the critical role of ARGs in shaping the immune landscape of LUSC. Virtual drug screening identified Dihydroergotamine as having the highest binding affinity for CSNK2A1. Molecular dynamics simulations confirmed that the CSNK2A1-Dihydroergotamine complex exhibited strong binding stability. Further in vitro experiments demonstrated that Dihydroergotamine significantly inhibited LUSC cell viability, migration, and invasion, and downregulated CSNK2A1 expression.

Conclusion

This study is the first to construct an anoikis-related prognostic model for LUSC, highlighting its role in the tumor immune microenvironment and providing insights into personalized therapy. Dihydroergotamine exhibited significant anti-LUSC activity and holds promise as a potential therapeutic agent. CSNK2A1 emerged as a robust candidate for early diagnosis and a therapeutic target in LUSC.

Single-nucleus and spatial landscape of the sub-ventricular zone in human glioblastoma

The sub-ventricular zone (SVZ) is the most well-characterized neurogenic area in the mammalian brain. We previously showed that in 65% of patients with glioblastoma (GBM), the SVZ is a reservoir of cancer stem-like cells that contribute to treatment resistance and the emergence of recurrence. Here, we build a single-nucleus RNA-sequencing-based microenvironment landscape of the tumor mass and the SVZ of 15 patients and two histologically normal SVZ samples as controls. We identify a ZEB1-centered mesenchymal signature in the tumor cells of the SVZ. Moreover, the SVZ microenvironment is characterized by tumor-supportive microglia, which spatially coexist and establish crosstalks with tumor cells. Last, differential gene expression analyses, predictions of ligand-receptor and incoming/outgoing interactions, and functional assays reveal that the interleukin (IL)-1β/IL-1RAcP and Wnt-5a/Frizzled-3 pathways represent potential therapeutic targets in the SVZ. Our data provide insights into the biology of the SVZ in patients with GBM and identify potential targets of this microenvironment.

Is modulation of immune checkpoints on glioblastoma-infiltrating myeloid cells a viable therapeutic strategy?

The field of immunology has traditionally focused on immune checkpoint modulation of adaptive immune cells. However, many malignancies such as glioblastoma are mostly devoid of T cells and rather are enriched with immunosuppressive myeloid cells of the innate immune system. While some immune checkpoint targets are shared between adaptive and innate immunity, myeloid-specific checkpoints could also serve as potential therapeutics. To better understand the impact of immune checkpoint blockade on myeloid cells, we systematically summarize the current literature focusing on the direct immunological effects of PD-L1/PD-1, CD24/Siglec-10, collagen/LAIR-1, CX3CL1/CX3CR1, and CXCL10/CXCR3. By synthesizing the molecular mechanisms and the translational implications, we aim to prioritize agents in this category of therapeutics for glioblastoma.

Markers of tumor-associated macrophages and microglia exhibit high intratumoral heterogeneity in human glioblastoma tissue

BACKGROUND

Human glioblastoma multiforme (GBM) is a highly aggressive tumor with insufficient therapies available. Especially, novel concepts of immune therapies fail due to a complex immunosuppressive microenvironment, high mutational rates, and inter-patient variations. The intratumoral heterogeneity is currently not sufficiently investigated.

METHODS

Biopsies from six different locations were taken in a cohort of 16 GBM patients who underwent surgery. The tissue slides were analyzed utilizing high-content imaging microscopy and algorithm-based image quantification. Several immune markers for macrophage and microglia subpopulations were investigated. Flow cytometry was used to validate key results. Besides the surface marker, cytokines were measured and categorized based on their heterogenicity and overall expression.

RESULTS

M2-like antigens, including CD204, CD163, Arg1, and CSF1R, showed comparatively higher expression, with GFAP displaying the least intratumoral heterogeneity. In contrast, anti-tumor-macrophage-like antigens, such as PSGL-1, CD16, CD68, and MHC-II, exhibited low overall expression and concurrent high intratumoral heterogeneity. CD16 and PSGL-1 were the most heterogeneous antigens. High expression levels were observed for cytokines IL-6, VEGF, and CCL-2. VILIP-a was revealed to differentiate most in principle component analysis. Cytokines with the lowest overall expression, such as TGF-β1, β-NGF, TNF-α, and TREM1, showed low intratumoral heterogeneity, in contrast to βNGF, TNF-α, and IL-18, which displayed high heterogeneity despite low expression.

CONCLUSION

The study showed high intratumoral heterogeneity in GBM, emphasizing the need for a more detailed understanding of the tumor microenvironment. The described findings could be essential for future personalized treatment strategies and the implementation of reliable diagnostics in GBM.

Understanding the Immune System and Biospecimen-Based Response in Glioblastoma: A Practical Guide to Utilizing Signal Redundancy for Biomarker and Immune Signature Discovery

Glioblastoma (GBM) is a primary central nervous system malignancy with a median survival of 15-20 months. The presence of both intra- and intertumoral heterogeneity limits understanding of biological mechanisms leading to tumor resistance, including immune escape. An attractive field of research to examine treatment resistance are immune signatures composed of cluster of differentiation (CD) markers and cytokines. CD markers are surface markers expressed on various cells throughout the body, often associated with immune cells. Cytokines are the effector molecules of the immune system. Together, CD markers and cytokines can serve as useful biomarkers to reflect immune status in patients with GBM. However, there are gaps in the understanding of the intricate interactions between GBM and the peripheral immune system and how these interactions change with standard and immune-modulating treatments. The key to understanding the true nature of these interactions is through multi-omic analysis of tumor progression and treatment response. This review aims to identify potential non-invasive blood-based biomarkers that can contribute to an immune signature through multi-omic approaches, leading to a better understanding of immune involvement in GBM.

Development of a Prognostic Risk Model for Esophageal Cancer Based on M0 Macrophage-Related Genes

Background

This study investigates the prognostic value of M0 macrophage-related genes (M0MRGs) in esophageal cancer (ESCA) and identifies novel targets for immunotherapy.

Methods

Differentially expressed genes (DEGs) were screened with ESCA-related expression profile data (GSE5364 and GSE17351) from the GEO database, followed by GO and KEGG pathway enrichment analyses. Then, immune cell infiltration was examined with the CIBERSORT algorithm and multiplex fluorescence-based immunohistochemistry (MP-IHC). ESCA-related gene expression data and relevant clinical information were retrieved from TCGA. M0MRGs were identified with TCGA-ESCA based on Spearman's correlation coefficient. Additionally, LASSO and Cox regression analyses were conducted to further construct an M0MRG-related prognostic model. ATP6V0D2 and MMP12 expression in ESCA was analyzed with tissue microarray. Finally, the half maximal inhibitory concentrations (IC50) of commonly used chemotherapeutics in TCGA-ESCA were calculated with the "oncoPredict" R package.

Conclusion

In summary, ATP6V0D2 and MMP12 were crucial components in a prognostic risk model for ESCA and were associated with poor prognoses, implicating the involvement of elevated M0 macrophages in disease progression and providing potential therapeutic targets and strategies for ESCA.

Glioblastoma-associated macrophages: A key target in overcoming glioblastoma therapeutic resistance

Glioblastoma multiforme (GBM) is recognized as the most aggressive and malignant form of brain cancer, characterized by a highly heterogeneous phenotype, poor prognosis, and a median survival time of less than 16 months. Recent studies have highlighted the critical role of glioblastoma-associated macrophages (GAMs) in promoting tumor progression and resistance not only to immunotherapy but also to radiotherapy and chemotherapy. GAMs actively suppress immune responses, promote angiogenesis, facilitate tumor metastasis, and induce therapy resistance, through various mechanisms such as cytokines production, signaling pathways regulation, and angiogenesis. In this context, understanding these regulatory mechanisms is essential for developing efficient therapies. Preclinical studies have investigated diverse approaches to target these cells, both as monotherapies or in combination with other treatments. While these approaches have shown promise in strengthening antitumor immune responses in animal models, their clinical success remains to be fully determined. Herein, we provide a comprehensive overview of GAMs's role in GBM therapeutic resistance and summarizes existing approaches to target GAMs in overcoming tumor resistance.

Microglia and macrophages in glioblastoma: landscapes and treatment directions

Glioblastoma is the most common primary malignant tumour of the central nervous system and remains uniformly and rapidly fatal. The tumour-associated macrophage (TAM) compartment comprises brain-resident microglia and bone marrow-derived macrophages (BMDMs) recruited from the periphery. Immune-suppressive and tumour-supportive TAM cell states predominate in glioblastoma, and immunotherapies, which have achieved striking success in other solid tumours have consistently failed to improve survival in this 'immune-cold' niche context. Hypoxic and necrotic regions in the tumour core are found to enrich, especially in anti-inflammatory and immune-suppressive TAM cell states. Microglia predominate at the invasive tumour margin and express pro-inflammatory and interferon TAM cell signatures. Depletion of TAMs, or repolarisation towards a pro-inflammatory state, are appealing therapeutic strategies and will depend on effective understanding and classification of TAM cell ontogeny and state based on new single-cell and spatial multi-omic in situ profiling. Here, we explore the application of these datasets to expand and refine TAM characterisation, to inform improved modelling approaches, and ultimately underpin the effective manipulation of function.

The roles of extracellular vesicles in gliomas: Challenge or opportunity?

Gliomas are increasingly becoming a major disease affecting human health, and current treatments are not as effective as expected. Deeper insights into glioma heterogeneity and the search for new diagnostic and therapeutic strategies appear to be urgent. Gliomas adapt to their surroundings and form a supportive tumor microenvironment (TME). Glioma cells will communicate with the surrounding cells through extracellular vesicles (EVs) carrying bioactive substances such as nucleic acids, proteins and lipids which is related to the modification to various metabolic pathways and regulation of biological behaviors, and this regulation can be bidirectional, widely existing between cells in the TME, constituting a complex network of interactions. This complex regulation can affect glioma therapy, leading to different types of resistance. Because of the feasibility of EVs isolation in various body fluids, they have a promising usage in the diagnosis and monitoring of gliomas. At the same time, the nature of EVs to cross the blood-brain barrier (BBB) confers potential for their use as drug delivery systems. In this review, we will focus on the roles and functions of EVs derived from different cellular origins in the glioma microenvironment and the intercellular regulatory networks, and explore possible clinical applications in glioma diagnosis and precision therapy.

Immunological challenges and opportunities in glioblastoma multiforme: A comprehensive view from immune system lens

Glioblastoma multiforme (GBM), also known as grade IV astrocytoma, is the most common and deadly brain tumour. It has a poor prognosis and a low survival rate. GBM cells' immunological escape mechanism helps them resist advanced multimodal therapy. In physiological homeostasis, brain astrocytes and microglia suppress infections and clear the potential pathogen from the system. However, in severe pathological conditions like cancer, the immune response fails to eliminate mutated and rapidly over-proliferating GBM cells. The malignant cells' interactions with immune cells and the neoplasm's immunosuppressive environment enable the avoidance and their clearance. Immunotherapy efficiently addresses these difficulties, as shown by sufficient evidence. This review discusses how GBM cells inhibit and elude the immune system. These include MHC molecule expression alteration and PD-L1 and CTLA-4 immune checkpoint overexpression. Without co-stimulation, these changes induce effector T-cell tolerance and anergy. The review also covers how MDSCs, TAMs, Herpes Virus Entry Mediators, and Human cytomegalovirus protein decrease the effector immune response against glioblastoma. The latter part discusses various therapies that are available in the market or under clinical trials which revolves around combating resistance against the available multimodal therapies. The recent trends indicate that there are various monoclonal antibodies and peptide-based vaccines that can be utilized to overcome the immune evasion technique harbored by GBM cells. A strategic development of Immunotherapy considering these hallmarks of immune evasion may help in designing a therapy that may prove to be effective in killing the GBM cells thereby, improving the overall survival of GBM-affected patients.

Challenges and Outlooks in Precision Medicine: Expectations Versus Reality

Recent developments in technology have led to rapid advances in precision medicine, especially due to the rise of next-generation sequencing and molecular profiling. These technological advances have led to rapid advances in research, including increased tumor subtype resolution, new therapeutic agents, and mechanistic insights. Certain therapies have even been approved for molecular biomarkers across histopathological diagnoses; however, translation of research findings to the clinic still faces a number of challenges. In this review, the authors discuss several key challenges to the clinical integration of precision medicine, including the blood-brain barrier, both a lack and excess of molecular targets, and tumor heterogeneity/escape from therapy. They also highlight a few key efforts to address these challenges, including new frontiers in drug delivery, a rapidly expanding treatment repertoire, and improvements in active response monitoring. With continued improvements and developments, the authors anticipate that precision medicine will increasingly become the gold standard for clinical care.

Characterisation of the tumour microenvironment in primary and recurrent glioblastomas

AIMS

Glioblastoma patients have a dismal prognosis, due to inevitable tumour recurrence and respond poorly to immunotherapy. Tumour-associated microglia/macrophages (TAMs) dominate the glioblastoma tumour microenvironment and have been implicated in tumour progression and immune evasion. Early recurrent glioblastomas contain focal reactive regions with occasional fibrosis, chronic inflammation, TAMs and tumour cells. Surgical specimens from these tumours are rare and provide crucial insights into glioblastoma recurrence biology. This study aimed to characterise TAM- and lymphocyte phenotypes in primary vs early- and late-recurrent glioblastomas.

METHODS

Patient-matched primary and recurrent glioblastomas were compared between patients with early recurrences (n = 11, recurrence ≤6 months) and late recurrences (n = 12, recurrence after 12-19 months). Double-immunofluorescence stains combining Iba1 with HLA-DR, CD14, CD68, CD74, CD86, CD163, CD204 and CD206 along with stains for CD20, CD3, CD8 and FOXP3 were quantified with software-based classifiers.

RESULTS

Reactive regions in early recurrent tumours contained more TAMs (31.4% vs 21.7%, P = 0.01), which showed increased expression of CD86 (59.4% vs 38.4%, P = 0.04), CD204 (48.5% vs 28.4%, P = 0.03), CD206 (25.5% vs 14.4%, P = 0.04) and increased staining intensity for CD163 (86.4 vs 57.7 arbitrary units, P = 0.02), compared to late recurring tumours. Reactive regions contained more B-lymphocytes compared to patient-matched primary tumours (0.71% vs 0.40%, P = 0.04). Fractions of total, cytotoxic and regulatory T-lymphocytes did not differ.

CONCLUSIONS

Early recurrent glioblastomas showed enrichment for TAMs, expressing both pro- and anti-inflammatory markers and B-lymphocytes. This may indicate a time-dependent response to immunotherapy explained by time-dependent alterations in the immune-microenvironment in recurrent glioblastomas.

Radiation immunodynamics in patients with glioblastoma receiving chemoradiation

Introduction

This is a prospective, rigorous inquiry into the systemic immune effects of standard adjuvant chemoradiotherapy, for WHO grade 4, glioblastoma. The purpose is to identify peripheral immunologic effects never yet reported in key immune populations, including myeloid-derived suppressor cells, which are critical to the immune suppressive environment of glioblastoma. We hypothesize that harmful immune-supportive white blood cells, myeloid derived suppressor cells, expand in response to conventionally fractionated radiotherapy with concurrent temozolomide, essentially promoting systemic immunity similar what is seen in chronic diseases like diabetes and heart disease.

Methods

16 patients were enrolled in a single-institution, observational, immune surveillance study where peripheral blood was collected and interrogated by flow cytometry and RNAseq. Tumor tissue from baseline assessment was analyzed with spatial proteomics to link peripheral blood findings to baseline tissue characteristics.

Results

We identified an increase in myeloid-derived suppressor cells during the final week of a six-week treatment of chemoradiotherapy in peripheral blood of patients that were not alive at two years after diagnosis compared to those who were living. This was also associated with a decrease in CD8+ T lymphocytes that produced IFNγ, the potent anti-tumor cytokine.

Discussion

These data suggest that, as in chronic inflammatory disease, systemic immunity is impaired following delivery of adjuvant chemoradiotherapy. Finally, baseline investigation of myeloid cells within tumor tissue did not differ between survival groups, indicating immune surveillance of peripheral blood during adjuvant therapy may be a critical missing link to educate our understanding of the immune effects of standard of care therapy for glioblastoma.

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.

Decoding the secret of extracellular vesicles in the immune tumor microenvironment of the glioblastoma: on the border of kingdoms

Over the last decades, extracellular vesicles (EVs) have become increasingly popular for their roles in various pathologies, including cancer and neurological and immunological disorders. EVs have been considered for a long time as a means for normal cells to get rid of molecules it no longer needs. It is now well established that EVs play their biological roles also following uptake or by the interaction of EV surface proteins with cellular receptors and membranes. In this review, we summarize the current status of EV production and secretion in glioblastoma, the most aggressive type of glioma associated with high mortality. The main purpose is to shed light on the EVs as a universal mediator of interkingdom and intrakingdom communication in the context of tumor microenvironment heterogeneity. We focus on the immunomodulatory EV functions in glioblastoma-immune cross-talk to enhance immune escape and reprogram tumor-infiltrating immune cells. We critically examine the evidence that GBM-, immune cell-, and microbiome-derived EVs impact local tumor microenvironment and host immune responses, and can enter the circulatory system to disseminate and drive premetastatic niche formation in distant organs. Taking into account the current state of the art in intratumoral microbiome studies, we discuss the emerging role of bacterial EV in glioblastoma and its response to current and future therapies including immunotherapies.

Expressions of the satellite repeat HSAT5 and transposable elements are implicated in disease progression and survival in glioma

The glioma genome encompasses a complex array of dysregulatory events, presenting a formidable challenge in managing this devastating disease. Despite the widespread distribution of repeat and transposable elements across the human genome, their involvement in glioma's molecular pathology and patient survival remains largely unexplored. In this study, we aimed to characterize the links between the expressions of repeat/transposable elements with disease progression and survival in glioma patients. Hence, we analyzed the expression levels of satellite repeats and transposons along with genes in low-grade glioma (LGG) and high-grade glioma (HGG). Endogenous transposable elements LTR5 and HERV_a-int exhibited higher expression in HGG patients, along with immune response-related genes. Altogether, 16 transposable elements were associated with slower progression of disease in LGG patients. Conversely, 22 transposons and the HSAT5 satellite repeat were linked to a shorter event-free survival in HGG patients. Intriguingly, our weighted gene coexpression network analysis (WGCNA) disclosed that the HSAT5 satellite repeat resided in the same module network with genes implicated in chromosome segregation and nuclear division; potentially hinting at its contribution to disease pathogenesis. Collectively, we report for the first time that repeat and/or transposon expression could be related to disease progression and survival in glioma. The expressions of these elements seem to exert a protective effect during LGG-to-HGG progression, whereas they could have a detrimental impact once HGG is established. The results presented herein could serve as a foundation for further experimental work aimed at elucidating the molecular regulation of glioma genome.

Current approaches in glioblastoma multiforme immunotherapy

Glioblastoma multiform (GBM) is the most prevalent CNS (central nervous system) tumor in adults, with an average survival length shorter than 2 years and rare metastasis to organs other than CNS. Despite extensive attempts at surgical resecting, the inherently permeable nature of this disease has rendered relapse nearly unavoidable. Thus, immunotherapy is a feasible alternative, as stimulated immune cells can enter into the remote and inaccessible tumor cells. Immunotherapy has revolutionized patient upshots in various malignancies and might introduce different effective ways for GBM patients. Currently, researchers are exploring various immunotherapeutic strategies in patients with GBM to target both the innate and acquired immune responses. These approaches include reprogrammed tumor-associated macrophages, the use of specific antibodies to inhibit tumor progression and metastasis, modifying tumor-associated macrophages with antibodies, vaccines that utilize tumor-specific dendritic cells to activate anti-tumor T cells, immune checkpoint inhibitors, and enhanced T cells that function against tumor cells. Despite these findings, there is still room for improving the response faults of the many currently tested immunotherapies. This study aims to review the currently used immunotherapy approaches with their molecular mechanisms and clinical application in GBM.

Protocol to quantify immune cell distribution from the vasculature to the glioma microenvironment on sequential immunofluorescence multiplex images

Although myeloid-derived immune cells can be dispersed throughout the tumor microenvironment (TME), anti-tumor effector cells are confined to the perivascular space. Here, we present a protocol to quantify immune cell distribution from tumor vasculature to its glioma microenvironment on sequential immunofluorescence multiplex images. We describe steps for sequential immunofluorescence multiplex staining, image generation, and storage. We then detail the procedures for tissue, vessel, and nuclei segmentation; cell phenotyping; data extraction; and training using RStudio and Spyder.

Identification of a risk model for prognostic and therapeutic prediction in renal cell carcinoma based on infiltrating M0 cells

The tumor microenvironment (TME) comprises immune-infiltrating cells that are closely linked to tumor development. By screening and analyzing genes associated with tumor-infiltrating M0 cells, we developed a risk model to provide therapeutic and prognostic guidance in clear cell renal cell carcinoma (ccRCC). First, the infiltration abundance of each immune cell type and its correlation with patient prognosis were analyzed. After assessing the potential link between the depth of immune cell infiltration and prognosis, we screened the infiltrating M0 cells to establish a risk model centered on three key genes (TMEN174, LRRC19, and SAA1). The correlation analysis indicated a positive correlation between the risk score and various stages of the tumor immune cycle, including B-cell recruitment. Furthermore, the risk score was positively correlated with CD8 expression and several popular immune checkpoints (ICs) (TIGIT, CTLA4, CD274, LAG3, and PDCD1). Additionally, the high-risk group (HRG) had higher scores for tumor immune dysfunction and exclusion (TIDE) and exclusion than the low-risk group (LRG). Importantly, the risk score was negatively correlated with the immunotherapy-related pathway enrichment scores, and the LRG showed a greater therapeutic benefit than the HRG. Differences in sensitivity to targeted drugs between the HRG and LRG were analyzed. For commonly used targeted drugs in RCC, including axitinib, pazopanib, temsirolimus, and sunitinib, LRG had lower IC50 values, indicating increased sensitivity. Finally, immunohistochemistry results of 66 paraffin-embedded specimens indicated that SAA1 was strongly expressed in the tumor samples and was associated with tumor metastasis, stage, and grade. SAA1 was found to have a significant pro-tumorigenic effect by experimental validation. In summary, these data confirmed that tumor-infiltrating M0 cells play a key role in the prognosis and treatment of patients with ccRCC. This discovery offers new insights and directions for the prognostic prediction and treatment of ccRCC.

Biomaterial strategies for regulating the neuroinflammatory response

Injury and disease in the central nervous system (CNS) can result in a dysregulated inflammatory environment that inhibits the repair of functional tissue. Biomaterials present a promising approach to tackle this complex inhibitory environment and modulate the mechanisms involved in neuroinflammation to halt the progression of secondary injury and promote the repair of functional tissue. In this review, we will cover recent advances in biomaterial strategies, including nanoparticles, hydrogels, implantable scaffolds, and neural probe coatings, that have been used to modulate the innate immune response to injury and disease within the CNS. The stages of inflammation following CNS injury and the main inflammatory contributors involved in common neurodegenerative diseases will be discussed, as understanding the inflammatory response to injury and disease is critical for identifying therapeutic targets and designing effective biomaterial-based treatment strategies. Biomaterials and novel composites will then be discussed with an emphasis on strategies that deliver immunomodulatory agents or utilize cell-material interactions to modulate inflammation and promote functional tissue repair. We will explore the application of these biomaterial-based strategies in the context of nanoparticle- and hydrogel-mediated delivery of small molecule drugs and therapeutic proteins to inflamed nervous tissue, implantation of hydrogels and scaffolds to modulate immune cell behavior and guide axon elongation, and neural probe coatings to mitigate glial scarring and enhance signaling at the tissue-device interface. Finally, we will present a future outlook on the growing role of biomaterial-based strategies for immunomodulation in regenerative medicine and neuroengineering applications in the CNS.

Non-Tumor Cells within the Tumor Microenvironment-The "Eminence Grise" of the Glioblastoma Pathogenesis and Potential Targets for Therapy

Glioblastoma (GBM) is the most common malignancy of the central nervous system in adults. GBM has high levels of therapy failure and its prognosis is usually dismal. The phenotypic heterogeneity of the tumor cells, dynamic complexity of non-tumor cell populations within the GBM tumor microenvironment (TME), and their bi-directional cross-talk contribute to the challenges of current therapeutic approaches. Herein, we discuss the etiology of GBM, and describe several major types of non-tumor cells within its TME, their impact on GBM pathogenesis, and molecular mechanisms of such an impact. We also discuss their value as potential therapeutic targets or prognostic biomarkers, with reference to the most recent works on this subject. We conclude that unless all "key player" populations of non-tumor cells within the TME are considered, no breakthrough in developing treatment for GBM can be achieved.

Neutrophils in glioma microenvironment: from immune function to immunotherapy

Glioma is a malignant tumor of the central nervous system (CNS). Currently, effective treatment options for gliomas are still lacking. Neutrophils, as an important member of the tumor microenvironment (TME), are widely distributed in circulation. Recently, the discovery of cranial-meningeal channels and intracranial lymphatic vessels has provided new insights into the origins of neutrophils in the CNS. Neutrophils in the brain may originate more from the skull and adjacent vertebral bone marrow. They cross the blood-brain barrier (BBB) under the action of chemokines and enter the brain parenchyma, subsequently migrating to the glioma TME and undergoing phenotypic changes upon contact with tumor cells. Under glycolytic metabolism model, neutrophils show complex and dual functions in different stages of cancer progression, including participation in the malignant progression, immune suppression, and anti-tumor effects of gliomas. Additionally, neutrophils in the TME interact with other immune cells, playing a crucial role in cancer immunotherapy. Targeting neutrophils may be a novel generation of immunotherapy and improve the efficacy of cancer treatments. This article reviews the molecular mechanisms of neutrophils infiltrating the central nervous system from the external environment, detailing the origin, functions, classifications, and targeted therapies of neutrophils in the context of glioma.

Triggering receptor expressed on myeloid cells 2 (TREM2) regulates phagocytosis in glioblastoma

BACKGROUND

Glioblastomas (GBMs) are central nervous system tumors that resist standard-of-care interventions and even immune checkpoint blockade. Myeloid cells in the tumor microenvironment can contribute to GBM progression; therefore, emerging immunotherapeutic approaches include reprogramming these cells to achieve desirable antitumor activity. Triggering receptor expressed on myeloid cells 2 (TREM2) is a myeloid signaling regulator that has been implicated in a variety of cancers and neurological diseases with contrasting functions, but its role in GBM immunopathology and progression is still under investigation.

METHODS

Our reverse translational investigations leveraged single-cell RNA sequencing and cytometry of human gliomas to characterize TREM2 expression across myeloid subpopulations. Using 2 distinct murine glioma models, we examined the role of Trem2 on tumor progression and immune modulation of myeloid cells. Furthermore, we designed a method of tracking phagocytosis of glioma cells in vivo and employed in vitro assays to mechanistically understand the influence of TREM2 signaling on tumor uptake.

RESULTS

We discovered that TREM2 expression does not correlate with immunosuppressive pathways, but rather showed strong a positive association with the canonical phagocytosis markers lysozyme (LYZ) and macrophage scavenger receptor (CD163) in gliomas. While Trem2 deficiency was found to be dispensable for gliomagenesis, Trem2+ myeloid cells display enhanced tumor uptake compared to Trem2- cells. Mechanistically, we demonstrate that TREM2 mediates phagocytosis via Syk signaling.

CONCLUSIONS

These results indicate that TREM2 is not associated with immunosuppression in gliomas. Instead, TREM2 is an important regulator of phagocytosis that may be exploited as a potential therapeutic strategy for brain tumors.

SorLA restricts TNFα release from microglia to shape a glioma-supportive brain microenvironment

SorLA, encoded by the gene SORL1, is an intracellular sorting receptor of the VPS10P domain receptor gene family. Although SorLA is best recognized for its ability to shuttle target proteins between intracellular compartments in neurons, recent data suggest that also its microglial expression can be of high relevance for the pathogenesis of brain diseases, including glioblastoma (GBM). Here, we interrogated the impact of SorLA on the functional properties of glioma-associated microglia and macrophages (GAMs). In the GBM microenvironment, GAMs are re-programmed and lose the ability to elicit anti-tumor responses. Instead, they acquire a glioma-supporting phenotype, which is a key mechanism promoting glioma progression. Our re-analysis of published scRNA-seq data from GBM patients revealed that functional phenotypes of GAMs are linked to the level of SORL1 expression, which was further confirmed using in vitro models. Moreover, we demonstrate that SorLA restrains secretion of TNFα from microglia to restrict the inflammatory potential of these cells. Finally, we show that loss of SorLA exacerbates the pro-inflammatory response of microglia in the murine model of glioma and suppresses tumor growth.

Upregulation of HLA-II related to LAG-3+CD4+ T cell infiltration is associated with patient outcome in human glioblastoma

Glioblastoma (GBM) is the most common malignant diffuse glioma of the brain. Although immunotherapy with immune checkpoint inhibitors (ICIs), such as programmed cell death protein (PD)-1/PD ligand-1 inhibitors, has revolutionized the treatment of several cancers, the clinical benefit in GBM patients has been limited. Lymphocyte-activation gene 3 (LAG-3) binding to human leukocyte antigen-II (HLA-II) plays an essential role in triggering CD4+ T cell exhaustion and could interfere with the efficiency of anti-PD-1 treatment; however, the value of LAG-3-HLA-II interactions in ICI immunotherapy for GBM patients has not yet been analyzed. Therefore, we aimed to investigate the expression and regulation of HLA-II in human GBM samples and the correlation with LAG-3+CD4+ T cell infiltration. Human leukocyte antigen-II was highly expressed in GBM and correlated with increased LAG-3+CD4+ T cell infiltration in the stroma. Additionally, HLA-IIHighLAG-3High was associated with worse patient survival. Increased interleukin-10 (IL-10) expression was observed in GBM, which was correlated with high levels of HLA-II and LAG-3+ T cell infiltration in stroma. HLA-IIHighIL-10High GBM associated with LAG-3+ T cells infiltration synergistically showed shorter overall survival in patients. Combined anti-LAG-3 and anti-IL-10 treatment inhibited tumor growth in a mouse brain GL261 tumor model. In vitro, CD68+ macrophages upregulated HLA-II expression in GBM cells through tumor necrosis factor-α (TNF-α). Blocking TNF-α-dependent inflammation inhibited tumor growth in a mouse GBM model. In summary, T cell-tumor cell interactions, such as LAG-3-HLA-II, could confer an immunosuppressive environment in human GBM, leading to poor prognosis in patients. Therefore, targeting the LAG-3-HLA-II interaction could be beneficial in ICI immunotherapy to improve the clinical outcome of GBM patients.

Single-nucleus and spatial landscape of the sub-ventricular zone in human glioblastoma

The sub-ventricular zone (SVZ) is the most well-characterized neurogenic area in the mammalian brain. We previously showed that in 65% of patients with glioblastoma (GBM), the SVZ is a reservoir of cancer stem-like cells that contribute to treatment resistance and emergence of recurrence. Here, we built a single-nucleus RNA-sequencing-based microenvironment landscape of the tumor mass (T_Mass) and the SVZ (T_SVZ) of 15 GBM patients and 2 histologically normal SVZ (N_SVZ) samples as controls. We identified a mesenchymal signature in the T_SVZ of GBM patients: tumor cells from the T_SVZ relied on the ZEB1 regulatory network, whereas tumor cells in the T_Mass relied on the TEAD1 regulatory network. Moreover, the T_SVZ microenvironment was predominantly characterized by tumor-supportive microglia, which spatially co-exist and establish heterotypic interactions with tumor cells. Lastly, differential gene expression analyses, predictions of ligand-receptor and incoming/outgoing interactions, and functional assays revealed that the IL-1β/IL-1RAcP and Wnt-5a/Frizzled-3 pathways are therapeutic targets in the T_SVZ microenvironment. Our data provide insights into the biology of the SVZ in GBM patients and identify specific targets of this microenvironment.

A paclitaxel-hyaluronan conjugate (ONCOFID-P-B™) in patients with BCG-unresponsive carcinoma in situ of the bladder: a dynamic assessment of the tumor microenvironment

BACKGROUND

The intravesical instillation of the paclitaxel-hyaluronan conjugate ONCOFID-P-B™ in patients with bacillus Calmette-Guérin (BCG)-unresponsive bladder carcinoma in situ (CIS; NCT04798703 phase I study), induced 75 and 40% of complete response (CR) after 12 weeks of intensive phase and 12 months of maintenance phase, respectively. The aim of this study was to provide a detailed description of the tumor microenvironment (TME) of ONCOFID-P-B™-treated BCG-unresponsive bladder CIS patients enrolled in the NCT04798703 phase I study, in order to identify predictive biomarkers of response.

METHODS

The composition and spatial interactions of tumor-infiltrating immune cells and the expression of the most relevant hyaluronic acid (HA) receptors on cancer cells, were analyzed in biopsies from the 20 patients enrolled in the NCT04798703 phase I study collected before starting ONCOFID-P-B™ therapy (baseline), and after the intensive and the maintenance phases. Clinical data were correlated with cell densities, cell distribution and cell interactions. Associations between immune populations or HA receptors expression and outcome were analyzed using univariate Cox regression and log-rank analysis.

RESULTS

In baseline biopsies, patients achieving CR after the intensive phase had a lower density of intra-tumoral CD8+ cytotoxic T lymphocytes (CTL), but also fewer interactions between CTL and macrophages or T-regulatory cells, as compared to non-responders (NR). NR expressed higher levels of the HA receptors CD44v6, ICAM-1 and RHAMM. The intra-tumoral macrophage density was positively correlated with the expression of the pro-metastatic and aggressive variant CD44v6, and the combined score of intra-tumoral macrophage density and CD44v6 expression had an AUC of 0.85 (95% CI 0.68-1.00) for patient response prediction.

CONCLUSIONS

The clinical response to ONCOFID-P-B™ in bladder CIS likely relies on several components of the TME, and the combined evaluation of intra-tumoral macrophages density and CD44v6 expression is a potentially new predictive biomarker for patient response. Overall, our data allow to advance a potential rationale for combinatorial treatments targeting the immune infiltrate such as immune checkpoint inhibitors, to make bladder CIS more responsive to ONCOFID-P-B™ treatment.

SIRPB1 regulates inflammatory factor expression in the glioma microenvironment via SYK: functional and bioinformatics insights

BACKGROUND

SIRPB1 expression is upregulated in various tumor types, including gliomas, and is known to contribute to tumor progression; nevertheless, its function in the immune milieu of gliomas is still mainly unknown.

METHODS

This study, we analyzed 1152 normal samples from the GTEx database and 670 glioma samples from the TCGA database to investigate the relationship between the expression of SIRPB1 and clinicopathological features. Moreover, SIRPB1 gene knockout THP-1 cell lines were constructed using CRISPR/Cas9 and were induced into a co-culture of macrophages and glioma cells in vitro to learn more about the role of SIRPB1 in the glioma immune milieu. Lastly, we established a prognostic model to predict the effect of SIRPB1 on prognosis.

RESULTS

Significantly higher levels of SIRPB1 expression were found in gliomas, which had an adverse effect on the immune milieu and correlated poorly with patient survival. SIRPB1 activation with certain antibodies results in SYK phosphorylation and the subsequent activation of calcium, MAPK, and NF-κB signaling pathways. This phenomenon is primarily observed in myeloid-derived cells as opposed to glioma cells. In vitro co-culture demonstrated that macrophages with SIRPB1 knockout showed decreased IL1RA, CCL2, and IL-8, which were recovered upon ectopic expression of SIRPB1 but reduced again following treatment with SYK inhibitor GS9973. Critically, a lower overall survival rate was linked to increased SIRPB1 expression. Making use of SIRPB1 expression along with additional clinicopathological variables, we established a nomogram that showed a high degree of prediction accuracy.

CONCLUSIONS

Our study demonstrates that glioma cells can be activated by macrophages via SIRPB1, subsequently reprogramming the TME, suggesting that SIRPB1 could serve as a promising therapeutic target for gliomas.

Histone modification-linked prognostic model for ovarian cancer reveals LBX2 as a novel growth promoter

Ovarian cancer (OC) is a deadly disease with limited treatment options and poor overall survival rates. This study aimed to investigate the role of histone modification-related genes in predicting the prognosis of OC patients. Transcriptome data from multiple cohorts, including bulk RNA-Seq data and single-cell scRNA-Seq data, were collected. Gene set enrichment analysis was used to identify enriched gene sets in the histone modification pathway. Differentially expressed genes (DEGs) between histone modification-high and histone modification-low groups were identified using Lasso regression. A prognostic model was constructed using five selected prognostic genes from the DEGs in the TCGA-OV cohort. The study found enrichment of gene sets in the histone modification pathway and identified five prognostic genes associated with OC prognosis. The constructed risk score model based on histone modification-related genes was correlated with immune infiltration of T cells and M1 macrophages. Mutations are more prevalent in the high-risk group compared to the low-risk group. Several drugs were screened against the model genes. Through in vitro experiments, we confirmed the expression patterns of the model genes. LBX2 facilitates the proliferation of OC. Histone modification-related genes have the potential to serve as biomarkers for predicting OC prognosis. Targeting these genes may lead to the development of more effective therapies for OC. Additionally, LBX2 represents a novel cell proliferation promoter in OC carcinogenesis.

Pathway-based stratification of gliomas uncovers four subtypes with different TME characteristics and prognosis

Increasing evidences have found that the interactions between hypoxia, immune response and metabolism status in tumour microenvironment (TME) have clinical importance of predicting clinical outcomes and therapeutic efficacy. This study aimed to develop a reliable molecular stratification based on these key components of TME. The TCGA data set (training cohort) and two independent cohorts from CGGA database (validation cohort) were enrolled in this study. First, the enrichment score of 277 TME-related signalling pathways was calculated by gene set variation analysis (GSVA). Then, consensus clustering identified four stable and reproducible subtypes (AFM, CSS, HIS and GLU) based on TME-related signalling pathways, which were characterized by differences in hypoxia and immune responses, metabolism status, somatic alterations and clinical outcomes. Among the four subtypes, HIS subtype had features of immunosuppression, oxygen deprivation and active energy metabolism, resulting in a worst prognosis. Thus, for better clinical application of this acquired stratification, we constructed a risk signature by using the LASSO regression model to identify patients in HIS subtype accurately. We found that the risk signature could accurately screen out the patients in HIS subtype and had important reference value for individualized treatment of glioma patients. In brief, the definition of the TME-related subtypes was a valuable tool for risk stratification in gliomas. It might serve as a reliable prognostic classifier and provide rational design of individualized treatment, and follow-up scheduling for patients with gliomas.

Disulfiram Inhibits Opsonin-Independent Phagocytosis and Migration of Human Long-Lived In Vitro Cultured Phagocytes from Multiple Inflammatory Diseases

Disulfiram (DSF), an anti-alcoholism medicine, exerts treatment effects in patients suffering from persistent Borreliosis and also exhibits anti-cancer effects through its copper chelating derivatives and induction of oxidative stress in mitochondria. Since chronic/persistent borreliosis is characterized by increased amounts of pro-inflammatory macrophages, this study investigated opsonin-independent phagocytosis, migration, and surface marker expression of in vivo activated and in vitro cultured human monocyte-derived phagocytes (macrophages and dendritic cells) with and without DSF treatment. Phagocytosis of non-opsonized Dynabeads® M-450 and migration of macrophages and dendritic cells were monitored using live cell analyzer Juli™ Br for 24 h, imaging every 3.5 min. To simultaneously monitor phagocyte function, results were analyzed by a newly developed software based on the differential phase contrast images of cells before and after ingestion of Dynabeads. DSF decreased the phagocytic capacities exhibited by in vitro enriched and long-lived phagocytes. Although no chemotactic gradient was applied to the test system, vigorous spontaneous migration was observed. We therefore set up an algorithm to monitor and quantify both phagocytosis and migration simultaneously. DSF not only reduced phagocytosis in a majority of these long-lived phagocytes but also impaired their migration. Despite these selective effects by DSF, we found that DSF reduced the expression densities of surface antigens CD45 and CD14 in all of our long-lived phagocytes. In cells with a high metabolic activity and high mitochondrial contents, DSF led to cell death corresponding to mitochondrial oxidative stress, whereas metabolically inactive phagocytes survived our DSF treatment protocol. In conclusion, DSF affects the viability of metabolically active phagocytes by inducing mitochondrial stress and secondly attenuates phagocytosis and migration in some long-lived phagocytes.

Systemic and local immunosuppression in glioblastoma and its prognostic significance

The effectiveness of tumor therapy, especially immunotherapy and oncolytic virotherapy, critically depends on the activity of the host immune cells. However, various local and systemic mechanisms of immunosuppression operate in cancer patients. Tumor-associated immunosuppression involves deregulation of many components of immunity, including a decrease in the number of T lymphocytes (lymphopenia), an increase in the levels or ratios of circulating and tumor-infiltrating immunosuppressive subsets [e.g., macrophages, microglia, myeloid-derived suppressor cells (MDSCs), and regulatory T cells (Tregs)], as well as defective functions of subsets of antigen-presenting, helper and effector immune cell due to altered expression of various soluble and membrane proteins (receptors, costimulatory molecules, and cytokines). In this review, we specifically focus on data from patients with glioblastoma/glioma before standard chemoradiotherapy. We discuss glioblastoma-related immunosuppression at baseline and the prognostic significance of different subsets of circulating and tumor-infiltrating immune cells (lymphocytes, CD4+ and CD8+ T cells, Tregs, natural killer (NK) cells, neutrophils, macrophages, MDSCs, and dendritic cells), including neutrophil-to-lymphocyte ratio (NLR), focus on the immune landscape and prognostic significance of isocitrate dehydrogenase (IDH)-mutant gliomas, proneural, classical and mesenchymal molecular subtypes, and highlight the features of immune surveillance in the brain. All attempts to identify a reliable prognostic immune marker in glioblastoma tissue have led to contradictory results, which can be explained, among other things, by the unprecedented level of spatial heterogeneity of the immune infiltrate and the significant phenotypic diversity and (dys)functional states of immune subpopulations. High NLR is one of the most repeatedly confirmed independent prognostic factors for shorter overall survival in patients with glioblastoma and carcinoma, and its combination with other markers of the immune response or systemic inflammation significantly improves the accuracy of prediction; however, more prospective studies are needed to confirm the prognostic/predictive power of NLR. We call for the inclusion of dynamic assessment of NLR and other blood inflammatory markers (e.g., absolute/total lymphocyte count, platelet-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, systemic immune-inflammation index, and systemic immune response index) in all neuro-oncology studies for rigorous evaluation and comparison of their individual and combinatorial prognostic/predictive significance and relative superiority.

Hypoxic glioblastoma-cell-derived extracellular vesicles impair cGAS-STING activity in macrophages

BACKGROUND

Solid tumors such as glioblastoma (GBM) exhibit hypoxic zones that are associated with poor prognosis and immunosuppression through multiple cell intrinsic mechanisms. However, release of extracellular vesicles (EVs) has the potential to transmit molecular cargos between cells. If hypoxic cancer cells use EVs to suppress functions of macrophages under adequate oxygenation, this could be an important underlying mechanism contributing to the immunosuppressive and immunologically cold tumor microenvironment of tumors such as GBM.

METHODS

EVs were isolated by differential ultracentrifugation from GBM cell culture supernatant. EVs were thoroughly characterized by transmission and cryo-electron microscopy, nanoparticle tracking analysis (NTA), and EV marker expression by Western blot and fluorescent NTA. EV uptake by macrophage cells was observed using confocal microscopy. The transfer of miR-25/93 as an EV cargo to macrophages was confirmed by miRNA real-time qPCR. The impact of miR-25/93 on the polarization of recipient macrophages was shown by transcriptional analysis, cytokine secretion and functional assays using co-cultured T cells.

RESULTS

We show that indirect effects of hypoxia can have immunosuppressive consequences through an EV and microRNA dependent mechanism active in both murine and human tumor and immune cells. Hypoxia enhanced EV release from GBM cells and upregulated expression of miR-25/93 both in cells and in EV cargos. Hypoxic GBM-derived EVs were taken up by macrophages and the miR-25/93 cargo was transferred, leading to impaired cGAS-STING pathway activation revealed by reduced type I IFN expression and secretion by macrophages. The EV-treated macrophages downregulated expression of M1 polarization-associated genes Cxcl9, Cxcl10 and Il12b, and had reduced capacity to attract activated T cells and to reactivate them to release IFN-γ, key components of an efficacious anti-tumor immune response.

CONCLUSIONS

Our findings suggest a mechanism by which immunosuppressive consequences of hypoxia mediated via miRNA-25/93 can be exported from hypoxic GBM cells to normoxic macrophages via EVs, thereby contributing to more widespread T-cell mediated immunosuppression in the tumor microenvironment.

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.

Glioblastoma vaccines: past, present, and opportunities

Glioblastoma (GBM) is one of the most lethal central nervous systems (CNS) tumours in adults. As supplements to standard of care (SOC), various immunotherapies improve the therapeutic effect in other cancers. Among them, tumour vaccines can serve as complementary monotherapy or boost the clinical efficacy with other immunotherapies, such as immune checkpoint blockade (ICB) and chimeric antigen receptor T cells (CAR-T) therapy. Previous studies in GBM therapeutic vaccines have suggested that few neoantigens could be targeted in GBM due to low mutation burden, and single-peptide therapeutic vaccination had limited efficacy in tumour control as monotherapy. Combining diverse antigens, including neoantigens, tumour-associated antigens (TAAs), and pathogen-derived antigens, and optimizing vaccine design or vaccination strategy may help with clinical efficacy improvement. In this review, we discussed current GBM therapeutic vaccine platforms, evaluated and potential antigenic targets, current challenges, and perspective opportunities for efficacy improvement.

Current state of immune checkpoints therapy for glioblastoma

Glioblastoma (GBM), one of the most aggressive forms of brain cancer, has limited treatment options. Recent years have witnessed the remarkable success of checkpoint inhibitor immunotherapy across various cancer types. Against this backdrop, several clinical trials investigating checkpoint inhibitors for GBM are underway in multiple countries. Furthermore, the integration of immunotherapy with traditional treatment approaches is now emerging as a highly promising strategy. This review summarizes the latest advancements in checkpoint inhibitor immunotherapy for GBM treatment. We provide a concise yet comprehensive overview of current GBM immunotherapy options. Additionally, this review underscores combination strategies and potential biomarkers for predicting response and resistance in GBM immunotherapies.

Tumor-derived extracellular vesicles: how they mediate glioma immunosuppression

Gliomas, the most common malignant brain tumor, present a grim prognosis despite available treatments such as surgical resection, temozolomide (TMZ) therapy, and radiation therapy. This is due to their aggressive growth, high level of immunosuppression, and the blood-brain barrier (BBB), which obstruct the effective exchange of therapeutic drugs. Gliomas can significantly affect differentiation and function of immune cells by releasing extracellular vesicles (EVs), resulting in a systemic immunosuppressive state and a highly immunosuppressive microenvironment. In the tumor immune microenvironment (TIME), the primary immune cells are regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages (TAMs). In particular, glioma-associated TAMs are chiefly composed of monocyte-derived macrophages and brain-resident microglia. These cells partially exhibit characteristics of a pro-tumorigenic, anti-inflammatory M2-type. Glioma-derived EVs can hijack TAMs to differentiate into tumor-supporting phenotypes or directly affect the maturation of peripheral blood monocytes (PBMCs) and promote the activation of MDSCs. In addition, EVs impair the ability of dendritic cells (DCs) to process antigens, subsequently hindering the activation of lymphocytes. EVs also impact the proliferation, differentiation, and activation of lymphocytes. This is primarily evident in the overall reduction of CD4 + helper T cells and CD8 + T cells, coupled with a relative increase in Tregs, which possess immunosuppressive characteristics. This study investigates thoroughly how tumor-derived EVs impair the function of immune cells and enhance immunosuppression in gliomas, shedding light on their potential implications for immunotherapy strategies in glioma treatment.

Spatial and temporal heterogeneity of tumor immune microenvironment between primary tumor and brain metastases in NSCLC

BACKGROUND

Brain metastasis is a common outcome in non-small cell lung cancer, and despite aggressive treatment, its clinical outcome is still frustrating. In recent years, immunotherapy has been developing rapidly, however, its therapeutic outcomes for primary lung cancer and brain metastases are not the same, suggesting that there may be differences in the immune microenvironment of primary lung cancer and brain metastases, however, we currently know little about these differences.

METHODS

Seventeen paired samples of NSCLC and their brain metastases and 45 other unpaired brain metastases samples were collected for the current study. Immunohistochemical staining was performed on all samples for the following markers: immune checkpoints CTLA-4, PD-1, PD-L1, B7-H3, B7-H4, IDO1, and EphA2; tumor-infiltrating lymphocytes (TILs) CD3, CD4, CD8, and CD20; tumor-associated microglia/macrophages (TAMs) CD68 and CD163; and tumor proliferation index Ki-67. The differences in expression of these markers were compared in 17 paired samples, and the effect of the expression level of these markers on the prognosis of patients was analyzed in lung adenocarcinoma brain metastases samples. Subsequently, multiplex immunofluorescence staining was performed in a typical lung-brain paired sample based on the aforementioned results. The multiplex immunofluorescence staining results revealed the difference in tumor immune microenvironment between primary NSCLC and brain metastases.

RESULTS

In 17 paired lesions, the infiltration of CTLA-4+ (P = 0.461), PD-1+ (P = 0.106), CD3+ (P = 0.045), CD4+ (P = 0.037), CD8+ (P = 0.008), and CD20+ (P = 0.029) TILs in brain metastases were significantly decreased compared with primary tumors. No statistically significant difference was observed in the CD68 (P = 0.954) and CD163 (P = 0.654) TAM infiltration between primary NSCLC and paired brain metastases. In all the brain metastases lesions, the expression of PD-L1 is related to the time interval of brain metastases in NSCLC. In addition, the Cox proportional hazards regression models showed high expression of B7-H4 (hazard ratio [HR] = 3.276, 95% confidence interval [CI] 1.335-8.041, P = 0.010) and CD68 TAM infiltration (HR = 3.775, 95% CI 1.419-10.044, P = 0.008) were independent prognosis factors for lung adenocarcinoma brain metastases patients.

CONCLUSIONS

Both temporal and spatial heterogeneity is present between the primary tumor and brain metastases of NCSLC. Brain metastases lesions exhibit a more immunosuppressive tumor immune microenvironment. B7-H4 and CD68+ TAMs may have potential therapeutic value for lung adenocarcinoma brain metastases patients.