Transcriptomics-based characterization of the immuno-stromal microenvironment in pediatric low-grade glioma.

Immunologic treatment options are uncommon in low-grade gliomas, although such therapies might be beneficial for inoperable and aggressive cases. Knowledge of the immune and stromal cells in low-grade gliomas is highly relevant for such approaches but still needs to be improved. Published gene-expression data from 400 low-grade gliomas and 193 high-grade gliomas were gathered to quantify 10 microenvironment cell populations with a deconvolution method designed explicitly for brain tumors. First, we investigated general differences in the microenvironment of low- and high-grade gliomas. Lower-grade and high-grade tumors cluster together, respectively, and show a general similarity within and distinct differences between these groups, the main difference being a higher infiltration of fibroblasts and T cells in high-grade gliomas. Among the analyzed entities, gangliogliomas and pleomorphic xanthoastrocytomas presented the highest overall immune cell infiltration. Further analyses of the low-grade gliomas presented three distinct microenvironmental signatures of immune cell infiltration, which can be divided into T-cell/dendritic/natural killer cell-, neutrophilic/B lineage/natural killer cell-, and monocytic/vascular/stromal-cell-dominated immune clusters. These clusters correlated with tumor location, age, and histological diagnosis but not with sex or progression-free survival. A survival analysis showed that the prognosis can be predicted from gene expression, clinical data, and a combination of both with a support vector machine and revealed the negative prognostic relevance of vascular markers. Overall, our work shows that low- and high-grade gliomas can be characterized and differentiated by their immune cell infiltration. Low-grade gliomas cluster into three distinct immunologic tumor microenvironments, which may be of further interest for upcoming immunotherapeutic research.

Immunotherapy revolutionizing brain metastatic cancer treatment: personalized strategies for transformative outcomes.

Brain metastatic cancer poses a significant clinical challenge, with limited treatment options and poor prognosis for patients. In recent years, immunotherapy has emerged as a promising strategy for addressing brain metastases, offering distinct advantages over conventional treatments. This review explores the evolving landscape of tumor immunotherapy in the context of brain metastatic cancer, focusing on the intricate interplay between the tumor microenvironment (TME) and immunotherapeutic approaches. By elucidating the complex interactions within the TME, including the role of immune cells, cytokines, and extracellular matrix components, this review highlights the potential of immunotherapy to reshape the treatment paradigm for brain metastases. Leveraging immune checkpoint inhibitors, cellular immunotherapies, and personalized treatment strategies, immunotherapy holds promise in overcoming the challenges posed by the blood-brain barrier and immunosuppressive microenvironment of brain metastases. Through a comprehensive analysis of current research findings and future directions, this review underscores the transformative impact of immunotherapy on the management of brain metastatic cancer, offering new insights and opportunities for personalized and precise therapeutic interventions.

Anti-tumor effect of innovative tumor treatment device OM-100 through enhancing anti-PD-1 immunotherapy in glioblastoma growth.

Glioblastoma (GBM) is associated with a median survival rate of less than 15 months, necessitating innovative treatment approaches. This study investigates the safety and efficacy of the low-frequency magnetic field (LFMF) OM-100 instrument in GBM therapy. In vitro experiments utilized normal astrocyte and GBM cell lines, determining that OM-100 at 100 kHz for 72 h selectively targeted GBM cells without harming normal cells. Subsequent analyses revealed OM-100's impact on cell viability, apoptosis, migration, invasion, reactive oxide species levels, and PD-L1 expression. In vivo studies on mice with U87-induced GBM demonstrated OM-100's synergy with anti-PD-1 therapy, leading to significant tumor volume reduction and increased apoptosis. Notably, OM-100 exhibited safety in healthy mice. Overall, OM-100 could enhance anti-PD-1 immunotherapy effectiveness probably by directly inhibiting tumor proliferation and migration as well as promoting PD-L1 expression, offering a promising therapeutic strategy for GBM treatment.

A real-world observation of patients with glioblastoma treated with a personalized peptide vaccine.

Current treatment outcome of patients with glioblastoma (GBM) remains poor. Following standard therapy, recurrence is universal with limited survival. Tumors from 173 GBM patients are analysed for somatic mutations to generate a personalized peptide vaccine targeting tumor-specific neoantigens. All patients were treated within the scope of an individual healing attempt. Among all vaccinated patients, including 70 treated prior to progression (primary) and 103 treated after progression (recurrent), the median overall survival from first diagnosis is 31.9 months (95% CI: 25.0-36.5). Adverse events are infrequent and are predominantly grade 1 or 2. A vaccine-induced immune response to at least one of the vaccinated peptides is detected in blood samples of 87 of 97 (90%) monitored patients. Vaccine-specific T-cell responses are durable in most patients. Significantly prolonged survival is observed for patients with multiple vaccine-induced T-cell responses (53 months) compared to those with no/low induced responses (27 months; P = 0.03). Altogether, our results highlight that the application of personalized neoantigen-targeting peptide vaccine is feasible and represents a promising potential treatment option for GBM patients.

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

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

Progesterone boosts abiraterone-driven target and NK cell therapies against glioblastoma.

INTRODUCTION: Glioblastoma (GBM) poses a significant challenge in oncology, with median survival times barely extending beyond a year due to resistance to standard therapies like temozolomide (TMZ). This study introduces a novel therapeutic strategy combining progesterone (Prog) and abiraterone (Abi) aimed at enhancing GBM treatment efficacy by modulating the tumor microenvironment and augmenting NK cell-mediated immunity. METHODS: We employed in vitro and in vivo GBM models to assess the effects of Prog and Abi on cell viability, proliferation, apoptosis, and the immune microenvironment. Techniques included cell viability assays, Glo-caspase 3/7 apoptosis assays, RNA-seq and qPCR for gene expression, Seahorse analysis for mitochondrial function, HPLC-MS for metabolomics analysis, and immune analysis by flow cytometry to quantify NK cell infiltration. RESULTS: Prog significantly reduced the IC50 of Abi in TMZ-resistant GBM cell, suggesting the enhanced cytotoxicity. Treatment induced greater apoptosis than either agent alone, suppressed tumor growth, and prolonged survival in mouse models. Notably, there was an increase in CD3-/CD19-/CD56+/NK1.1+ NK cell infiltration in treated tumors, indicating a shift towards an anti-tumor immune microenvironment. The combination therapy also resulted in a reduction of MGMT expression and a suppression of mitochondrial respiration and glycolysis in GBM cells. CONCLUSION: The combination of Prog and Abi represents a promising therapeutic approach for GBM, showing potential in suppressing tumor growth, extending survival, and modulating the immune microenvironment. These findings warrant further exploration into the clinical applicability of this strategy to improve outcomes for GBM patients.

EphA3-targeted chimeric antigen receptor T cells are effective in glioma and generate curative memory T cell responses.

BACKGROUND: High-grade gliomas including glioblastoma (GBM) and diffuse midline gliomas (DMG) represent the most lethal and aggressive brain cancers where current treatment modalities offer limited efficacy. Chimeric antigen receptor (CAR) T cell therapies have emerged as a promising strategy, boasting tumor-specific targeting and the unique ability to penetrate the blood-brain barrier. However, the effective clinical application hinges on the optimal choice of antigen, with a limited number, currently under investigation. METHODS: We employed cell surface proteomic analysis of primary human high-grade glioma samples from both adult and pediatric patients. This led to the identification of Ephrin type-A receptor 3 (EphA3) as a prevalently expressed target. We engineered a second-generation EphA3-targeted CAR T cell and assessed function using in vitro and in vivo models of GBM and DMG. RESULTS: EphA3-targeted CAR T cells demonstrated robust antigen-specific killing of human GBM and DMG cell lines in vitro. In an orthotopic xenograft NSG mouse model, EphA3-targeted CAR T cells not only effectively eradicated tumors but also established a functional T cell population protective on rechallenge. Remarkably, mice rechallenged with a second contralateral orthotopic tumor implantation achieved complete tumor clearance and maintained a sustained complete response 6 months following initial treatment. CONCLUSION: Building on the proven safety profile of EphA3 antibodies in clinical settings, our study provides compelling preclinical evidence supporting the efficacy of EphA3-targeted CAR T cells against high-grade gliomas. These findings underscore the potential for transitioning this innovative therapy into clinical trials, aiming to revolutionize the treatment landscape for patients afflicted with these formidable brain cancers.

EphA3 CAR T cells are effective against glioblastoma in preclinical models.

BACKGROUND: Adoptive T-cell therapy targeting antigens expressed in glioblastoma has emerged as a potential therapeutic strategy to prevent or delay recurrence and prolong overall survival in this aggressive disease setting. Ephrin receptor A3 (EphA3), which is highly expressed in glioblastoma; in particular, on the tumor vasculature and brain cancer stem cells, is an ideal target for immune-based therapies. METHODS: We have designed an EphA3-targeted chimeric antigen receptor (CAR) using the single chain variable fragment of a novel monoclonal antibody, and assessed its therapeutic potential against EphA3-expressing patient-derived glioblastoma neurospheres, organoids and xenografted glioblastoma tumors in immunodeficient mice. RESULTS: In vitro expanded EphA3 CAR T cells from healthy individuals efficiently recognize and kill EphA3-positive glioblastoma cells in vitro. Furthermore, these effector cells demonstrated curative efficacy in an orthotopic xenograft model of glioblastoma. EphA3 CAR T cells were equally effective in targeting patient-derived neurospheres and infiltrate, disaggregate, and induce apoptosis in glioblastoma-derived organoids. CONCLUSIONS: This study provides compelling evidence supporting the therapeutic potential of EphA3 CAR T-cell therapy against glioblastoma by targeting EphA3 associated with brain cancer stem cells and the tumor vasculature. The ability to target patient-derived glioblastoma underscores the translational significance of this EphA3 CAR T-cell therapy in the pursuit of effective and targeted glioblastoma treatment strategies.

Extracellular Matrix Structure and Interaction with Immune Cells in Adult Astrocytic Tumors.

The extracellular matrix (ECM) is a dynamic set of molecules produced by the cellular component of normal and pathological tissues of the embryo and adult. ECM acts as critical regulator in various biological processes such as differentiation, cell proliferation, angiogenesis, and immune control. The most frequent primary brain tumors are gliomas and by far the majority are adult astrocytic tumors (AATs). The prognosis for patients with these neoplasms is poor and the treatments modestly improves survival. In the literature, there is a fair number of studies concerning the composition of the ECM in AATs, while the number of studies relating the composition of the ECM with the immune regulation is smaller. Circulating ECM proteins have emerged as a promising biomarker that reflect the general immune landscape of tumor microenvironment and may represent a useful tool in assessing disease activity. Given the importance it can have for therapeutic and prognostic purposes, the aim of our study is to summarize the biological properties of ECM components and their effects on the tumor microenvironment and to provide an overview of the interactions between major ECM proteins and immune cells in AATs. As the field of immunotherapy in glioma is quickly expanding, we retain that current data together with future studies on ECM organization and functions in glioma will provide important insights into the tuning of immunotherapeutic approaches.

HMGB1/TREM2 positive feedback loop drives the development of radioresistance and immune escape of glioblastoma by regulating TLR4/Akt signaling.

BACKGROUND: Radioresistance and immune escape are crucial reasons for unsatisfactory therapeutic effects of glioblastoma (GBM). Although triggering receptor expressed on myeloid cells-2 (TREM2) involved in forming immunosuppressive microenvironment, but the underlying mechanism and its roles in mediating cancer radioresistance remain unclear, moreover, the efficient delivery of drugs targeting TREM2 to GBM encounters serious challenges. Hence, this study aimed to elucidate the effect and mechanisms of targeted TREM2 silencing on reversing the radioresistance and immune escape of GBM aided by a glutathione-responsive biomimetic nanoparticle (NP) platform. METHODS: Radioresistant GBM cell lines and TREM2 stable knockdown GBM cell lines were firstly established. RNA sequencing, colony formation assay, western blot, enzyme-linked immunosorbent assay and co-immunoprecipitation assay were used to detect the molecular mechanisms of TREM2 in regulating the radioresistance and immune escape of GBM. The glutathione-responsive biomimetic NP, angiopep-2 (A2)- cell membrane (CM)-NP/siTREM2/spam1, was then constructed to triply and targeted inhibit TREM2 for in vivo study. Orthotopic GBM-bearing mouse models were established to evaluate the anti-GBM effect of TREM2 inhibition, multiplex immunofluorescence assay was conducted to detect the infiltration of immune cells. RESULTS: TREM2 was a regulator in accelerating the radioresistance and immune escape of GBM through participating in DNA damage repair and forming a positive feedback loop with high mobility group box 1 (HMGB1) to cascade the activation of Toll-like receptor 4 (TLR4)/protein kinase B (Akt) signaling. A2-CM-NP/siTREM2/spam1 was successfully synthesized with excellent passive targeting, active targeting and homologous targeting, and the in vivo results exhibited its remarkable anti-GBM therapeutic effect through promoting the infiltration of type 1 helper T cells and CD8+T cells, reducing the infiltration of type 2 helper T cells and regulatory T cells, repolarizing macrophages to M1-type, and decreasing the secretion of pro-tumor and immunosuppressive cytokines. CONCLUSIONS: Targeting TREM2 therapy is a promising avenue for optimizing radiotherapy and immunotherapy to improve the prognosis of GBM patients.

Targeted opening of the blood-brain barrier facilitates doxorubicin/anti-PD-1-based chemoimmunotherapy of glioblastoma.

Doxorubicin is a prototypical inducer of immunogenic cell death (ICD) that sensitizes to subsequent immunotherapy by PD-1 blockade. However, this systemic drug combination fails against glioblastoma, hidden behind the blood-brain barrier (BBB). A recent work delineates a biophysical method for BBB permeabilization that yields effective preclinical effects of chemoimmunotherapy.

Density of tertiary lymphoid structures predicts clinical outcome in breast cancer brain metastasis.

BACKGROUND: Patients with breast cancer brain metastases (BCBM) experience a rapid decline in their quality of life. Recently, tertiary lymphoid structures (TLSs), analogs of secondary lymphoid organs, have attracted extensive attention. However, the potential clinical implications of TLSs in BCBMs are poorly understood. In this study, we evaluated the density and composition of TLSs in BCBMs and described their prognostic value. METHODS: Clinicopathological data were collected from 98 patients (2015-2021). TLSs were evaluated, and a TLS scoring system was constructed. Differences in progression-free survival (PFS) and overall survival (OS) between groups were calculated using the Kaplan-Meier method. Immunohistochemistry and multiplex immunofluorescence (mIF) were used to assess TLSs heterogeneity. RESULTS: TLSs were identified in 47 patients with BCBM. High TLSs density indicated favorable survival (OS, p=0.003; PFS, p<0.001). TLS was positively associated with OS (p=0.0172) and PFS (p=0.0161) in the human epidermal growth factor receptor type 2-positive subtype, and with prolonged OS (p=0.0482) in the triple-negative breast cancer subtype. The mIF results showed significant differences in the percentages of T follicular helper (Tfh) cells, M2 macrophages, cytotoxic T lymphocytes, and CD8+TIM-3+ T lymphocytes between the groups of TLS scores 0-3 (cytotoxic T lymphocytes, p=0.044; Tfh, p=0.021; M2 macrophages, p=0.033; CD8+TIM-3+ T lymphocytes, p=0.018). Furthermore, novel nomograms incorporating the TLS scores and other clinicopathological predictors demonstrated prominent predictability of the 1-year, 3-year, and 5-year outcomes of BCBMs (area under the curve >0.800). CONCLUSION: Our results highlight the impact of TLSs abundance on the OS and PFS of patients with BCBM. Additionally, we described the immune composition of TLSs and proposed novel nomograms to predict the prognosis of patients with BCBM.

Histone acetylation risk model predicts prognosis and guides therapy selection in glioblastoma: implications for chemotherapy and anti-CTLA-4 immunotherapy.

BACKGROUND: Glioblastoma is characterized by high aggressiveness, frequent recurrence, and poor prognosis. Histone acetylation-associated genes have been implicated in its occurrence and development, yet their predictive ability in glioblastoma prognosis remains unclear. RESULTS: This study constructs a histone acetylation risk model using Cox and LASSO regression analyses to evaluate glioblastoma prognosis. We assessed the model's prognostic ability with univariate and multivariate Cox regression analyses. Additionally, immune infiltration was evaluated using ESTIMATE and TIMER algorithms, and the SubMAP algorithm was utilized to predict responses to CTLA4 inhibitor. Multiple drug databases were applied to assess drug sensitivity in high- and low-risk groups. Our results indicate that the histone acetylation risk model is independent and reliable in predicting prognosis. CONCLUSIONS: Low-risk patients showed higher immune activity and longer overall survival, suggesting anti-CTLA4 immunotherapy suitability, while high-risk patients might benefit more from chemotherapy. This model could guide personalized therapy selection for glioblastoma patients.

Elevated SLC3A2 associated with poor prognosis and enhanced malignancy in gliomas.

The role of SLC3A2, a gene implicated in disulfidptosis, has not been characterized in gliomas. This study aims to clarify the prognostic value of SLC3A2 and its influence on glioma. We evaluated the expression of SLC3A2 and its prognostic importance in gliomas using publicly accessible databases and our clinical glioma samples and with reliance on Meta and Cox regression analysis approaches. Functional enrichment analyses were performed to explore SLC3A2's function. Immune infiltration was evaluated using CIBERSORT, ssGSEA, and single-cell sequencing data. Additionally, Tumor immune dysfunction and exclusion (TIDE) and epithelial-mesenchymal transition scores were determined. CCK8, colony formation, migration, and invasion assays were utilized in vitro, and an orthotopic glioma xenograft model was employed in vivo, to investigate the role of SLC3A2 in gliomas. Bioinformatics analyses indicated high SLC3A2 expression correlates with adverse clinicopathological features and poor patient prognosis. Upregulated SLC3A2 influenced the tumor microenvironment by altering immune cell infiltration, particularly of macrophages, and tumor migration and invasion. SLC3A2 expression positively correlated with immune therapy indicators, including immune checkpoints and TIDE. Elevated SLC3A2 was revealed as an independent risk element for poor glioma prognosis through Cox regression analyses. In vitro experiments showed that reduced SLC3A2 expression decreased cell proliferation, migration, and invasion. In vivo, knockdown of SLC3A2 led to a reduction in tumor volume and prolonged survival in tumor-bearing mice. Therefore, SLC3A2 is a prognostic biomarker and associated with immune infiltration in gliomas.

Immuno-oncologic profiling of pediatric brain tumors reveals major clinical significance of the tumor immune microenvironment.

With the success of immunotherapy in cancer, understanding the tumor immune microenvironment (TIME) has become increasingly important; however in pediatric brain tumors this remains poorly characterized. Accordingly, we developed a clinical immune-oncology gene expression assay and used it to profile a diverse range of 1382 samples with detailed clinical and molecular annotation. In low-grade gliomas we identify distinct patterns of immune activation with prognostic significance in BRAF V600E-mutant tumors. In high-grade gliomas, we observe immune activation and T-cell infiltrates in tumors that have historically been considered immune cold, as well as genomic correlates of inflammation levels. In mismatch repair deficient high-grade gliomas, we find that high tumor inflammation signature is a significant predictor of response to immune checkpoint inhibition, and demonstrate the potential for multimodal biomarkers to improve treatment stratification. Importantly, while overall patterns of immune activation are observed for histologically and genetically defined tumor types, there is significant variability within each entity, indicating that the TIME must be evaluated as an independent feature from diagnosis. In sum, in addition to the histology and molecular profile, this work underscores the importance of reporting on the TIME as an essential axis of cancer diagnosis in the era of personalized medicine.

AGBL4 promotes malignant progression of glioblastoma via modulation of MMP-1 and inflammatory pathways.

Introduction: Glioblastoma multiforme (GBM), the most common primary malignant brain tumor, is notorious for its aggressive growth and dismal prognosis. This study aimed to elucidate the molecular underpinnings of GBM, particularly focusing on the role of AGBL4 and its connection to inflammatory pathways, to discover viable therapeutic targets. Methods: Single-cell sequencing was utilized to examine the expression levels of AGBL4 and functional assays were performed to assess the effects of AGBL4 modulation. Results: Our findings identified the significant upregulation of AGBL4 in GBM, which correlated with adverse clinical outcomes. Functional assays demonstrated that AGBL4 knockdown inhibited GBM cell proliferation, migration, and invasion and influenced inflammatory response pathways, while AGBL4 overexpression promoted these activities. Further investigation revealed that AGBL4 exerted its oncogenic effects through modulation of MMP-1, establishing a novel regulatory axis critical for GBM progression and inflammation. Discussion: Both AGBL4 and MMP-1 may be pivotal molecular targets, offering new avenues for targeted therapy in GBM management.

A Self-Cascade Penetrating Brain Tumor Immunotherapy Mediated by Near-Infrared II Cell Membrane-Disrupting Nanoflakes via Detained Dendritic Cells.

Immunotherapy can potentially suppress the highly aggressive glioblastoma (GBM) by promoting T lymphocyte infiltration. Nevertheless, the immune privilege phenomenon, coupled with the generally low immunogenicity of vaccines, frequently hampers the presence of lymphocytes within brain tumors, particularly in brain tumors. In this study, the membrane-disrupted polymer-wrapped CuS nanoflakes that can penetrate delivery to deep brain tumors via releasing the cell-cell interactions, facilitating the near-infrared II (NIR II) photothermal therapy, and detaining dendritic cells for a self-cascading immunotherapy are developed. By convection-enhanced delivery, membrane-disrupted amphiphilic polymer micelles (poly(methoxypoly(ethylene glycol)-benzoic imine-octadecane, mPEG-b-C18) with CuS nanoflakes enhances tumor permeability and resides in deep brain tumors. Under low-power NIR II irradiation (0.8 W/cm2), the intense heat generated by well-distributed CuS nanoflakes actuates the thermolytic efficacy, facilitating cell apoptosis and the subsequent antigen release. Then, the positively charged polymer after hydrolysis of the benzoic-imine bond serves as an antigen depot, detaining autologous tumor-associated antigens and presenting them to dendritic cells, ensuring sustained immune stimulation. This self-cascading penetrative immunotherapy amplifies the immune response to postoperative brain tumors but also enhances survival outcomes through effective brain immunotherapy.

Tumor biomechanics as a novel imaging biomarker to assess response to immunotherapy in a murine glioma model.

Glioblastoma is the most common and aggressive primary malignant brain tumor with poor prognosis. Novel immunotherapeutic approaches are currently under investigation. Even though magnetic resonance imaging (MRI) is the most important imaging tool for treatment monitoring, response assessment is often hampered by therapy-related tissue changes. As tumor and therapy-associated tissue reactions differ structurally, we hypothesize that biomechanics could be a pertinent imaging proxy for differentiation. Longitudinal MRI and magnetic resonance elastography (MRE) were performed to monitor response to immunotherapy with a toll-like receptor 7/8 agonist in orthotopic syngeneic experimental glioma. Imaging results were correlated to histology and light sheet microscopy data. Here, we identify MRE as a promising non-invasive imaging method for immunotherapy-monitoring by quantifying changes in response-related tumor mechanics. Specifically, we show that a relative softening of treated compared to untreated tumors is linked to the inflammatory processes following therapy-induced re-education of tumor-associated myeloid cells. Mechanistically, combined effects of myeloid influx and inflammation including extracellular matrix degradation following immunotherapy form the basis of treated tumors being softer than untreated glioma. This is a very early indicator of therapy response outperforming established imaging metrics such as tumor volume. The overall anti-tumor inflammatory processes likely have similar effects on human brain tissue biomechanics, making MRE a promising tool for gauging response to immunotherapy in glioma patients early, thereby strongly impacting patient pathway.