Necrotic reshaping of the glioma microenvironment drives disease progression

Insights of immune cell heterogeneity, tumor-initiated subtype transformation, drug resistance, treatment and detecting technologies in glioma microenvironment

BACKGROUND

With the gradual understanding of glioma development and the immune microenvironment, many immune cells have been discovered. Despite the growing comprehension of immune cell functions and the clinical application of immunotherapy, the precise roles and characteristics of immune cell subtypes, how glioma induces subtype transformation of immune cells and its impact on glioma progression have yet to be understood.

AIM OF THE REVIEW

In this review, we comprehensively center on the four major immune cells within the glioma microenvironment, particularly neutrophils, macrophages, lymphocytes, myeloid-derived suppressor cells (MDSCs), and other significant immune cells. We discuss (1) immune cell subtype markers, (2) glioma-induced immune cell subtype transformation, (3) the mechanisms of each subtype influencing chemotherapy resistance, (4) therapies targeting immune cells, and (5) immune cell-associated single-cell sequencing. Eventually, we identified the characteristics of immune cell subtypes in glioma, comprehensively summarized the exact mechanism of glioma-induced immune cell subtype transformation, and concluded the progress of single-cell sequencing in exploring immune cell subtypes in glioma.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In conclusion, we have analyzed the mechanism of chemotherapy resistance detailly, and have discovered prospective immunotherapy targets, excavating the potential of novel immunotherapies approach that synergistically combines radiotherapy, chemotherapy, and surgery, thereby paving the way for improved immunotherapeutic strategies against glioma and enhanced patient outcomes.

Targeting mesenchymal monocyte-derived macrophages to enhance the sensitivity of glioblastoma to temozolomide by inhibiting TNF/CELSR2/p65/Kla-HDAC1/EPAS1 axis

INTRODUCTION

Temozolomide (TMZ) resistance poses a significant challenge to the treatment of aggressive and highly lethal glioblastomas (GBM). Monocyte-derived Macrophages (MDM) within the tumor microenvironment are key factors contributing to TMZ resistance in GBM. Lactate-mediated histone lysine lactylation (Kla) plays a crucial role in the regulation of tumor progression. However, the mechanism through which MDM-induced Kla expression promotes TMZ resistance in GBM remains unclear.

OBJECTIVES

The objective of this study s to identify a subtype of MDM with therapeutic potential target and to elucidate the mechanisms through which this subtype of MDM contributes to tumor malignant progression and TMZ resistance.

METHODS

We integrated single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics data to evaluate whether mesenchymal (MES) MDM is associated with poor prognosis. By establishing a subtype model of GBM cells for the first time, we validated the mechanism by which MES-MDM promotes subtype conversion of tumor cells. Using patient-derived GBM organoids and an intracranial orthotopic GBM model, we demonstrated that targeting MES-MDM increased GBM sensitivity to TMZ treatment.

RESULTS

We identified a novel MDM subtype, MES-MDM, in the hypoxic niches of the perinecrotic region characterized by high TREM1 expression, which fueled GBM progression. Hypoxia drived MES-MDM signatures by activating ATF3 transcription. MES-MDM facilitated the transition from the NPC to the MES subtype in GBM cells, in which Histone Deacetylase 1 (HDAC1) Kla, induced by the TNF-CELSR2/p65 signaling pathway, promoted this conversion, thereby promoting TMZ resistance. Targeting MES-MDM with TREM1 inhibitory peptides amplified TMZ sensitivity, offering a potential strategy for overcoming resistance to therapy in GBM. Targeting TREM1 enhanced the effectiveness of anti-PD-1 immunotherapy.

CONCLUSION

This study provides a potential therapeutic strategy for patients with MES-subtype GBM by targeting MES-MDM in combination with TMZ or PD-1 antibody treatment.

A clinically relevant model and method to study necrosis as a driving force in glioma restructuring and progression

All glioblastoma (GBM) molecular subsets share the common trait of accelerated progression following necrosis, which cannot be adequately explained by cellular proliferation arising from accumulated genetic alterations. Counter to dogma that "cancer outgrows its blood supply," we suggest that development of necrosis is not merely a consequence of aggressive neoplastic growth but could be a contributing force causing tumor microenvironment (TME) restructuring and biologic progression. Mechanisms related to necrotic contributions are poorly understood due to a lack of methods to study necrosis as a primary variable. To reveal spatiotemporal changes related to necrosis directly, we developed a mouse model and methodology designed to induce clinically relevant thrombotic vaso-occlusion within GBMs in an immunocompetent RCAS/tv-a mouse model to study TME restructuring by intravital microscopy and demonstrate its impact on glioma progression. Diffuse high-grade gliomas are generated by introducing RCAS-PDGFB-RFP and RCAS-Cre in a Nestin/tv-a; TP53fl/fl PTENfl/fl background mouse. We then photoactivate Rose Bengal in specific, targeted blood vessels within the glioma to induce thrombosis, hypoxia, and necrosis. Following induced necrosis, GBMs undergo rapid TME restructuring and radial expansion, with immunosuppressive bone marrow-derived, tumor-associated macrophages (TAMs) and glioma stem cells (GSCs) increasing dramatically in the perinecrotic niche. Collectively, this model introduces necrosis as the primary variable and captures glioma TME and growth dynamics in a manner that will facilitate therapeutic development to antagonize these mechanisms of progression.

Comparative Clinical-Imaging and Histogenetic Analysis Between Astrocytoma IDH-Mutant Grade 4 and Glioblastoma IDH-Wildtype-Is There Really a Worse One?

Background: Brain tumors pose a significant health threat, leading to high morbidity and mortality rates. Astrocytoma IDH-mutant grade 4 (A4IDHmt) and glioblastoma IDH-wildtype (G4IDHwt) exhibit similar clinical and imaging characteristics. This study aims to highlight the differences in their clinical evolution and histogenetic aspects with the possible therapeutic impact, as well as the adverse prognostic factors in patient survival. Methods: We performed a 10-year retrospective study of grade 4 gliomas, evaluating immunomarkers and FISH tests. We also quantified tumor necrosis and microvascular density. Results: A total of 81 cases were identified; 54.32% were A4IDHmt. We observed that A4IDHmt patients were younger (34.10% under 50) and had a higher survival rate (4.55%). This group also exhibited a more pronounced microvascular density (p = 0.010) and proliferative index (p = 0.026). G4IDHwt was associated with larger tumor volumes (94.84 cm3 vs. 86.14 cm3), lower resectability rates (82.88% vs. 87.67%), and a more significant immature cell population (83.78% vs. 68.18%). In the case of both, the negative risk on survival in the univariate analysis is given by advanced age (A4IDHmt: HR = 1.035, G4IDHwt: HR = 1.045) and p53 immunopositivity (A4IDHmt: HR = 6.962, G4IDHwt: HR = 4.680). Conclusions: The negative risk factors for A4IDHmt include the rapid onset of clinical symptoms (HR = 2.038), diabetes mellitus (HR = 2.311), arterial hypertension (HR = 2.325), residual tumor (HR = 2.662), increased residual tumor volume (HR = 1.060), increased microvascular density (HR = 1.096), and high tumor necrosis (HR = 1.097). For G4IDHwt, the negative risk factors consist of increased residual volume (HR = 1.023), lost PTEN immunoreaction (HR = 33.133), and unmethylated DNA status (HR = 6.765, respectively HR = 20.573). Even if it has more risk factors, A4IDHmt is the lesser evil.

Preoperative prediction of IDH genotypes and prognosis in adult-type diffuse gliomas: intratumor heterogeneity habitat analysis using dynamic contrast-enhanced MRI and diffusion-weighted imaging

BACKGROUND

Intratumor heterogeneity (ITH) is a key biological characteristic of gliomas. This study aimed to characterize ITH in adult-type diffuse gliomas and assess the feasibility of using habitat imaging based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) to preoperatively predict isocitrate dehydrogenase (IDH) genotypes and prognosis.

METHODS

Sixty-three adult-type diffuse gliomas with known IDH genotypes were enrolled. Volume transfer constant (Ktrans) and apparent diffusion coefficient (ADC) maps were acquired from DCE-MRI and DWI, respectively. After tumor segmentation, the k-means algorithm clustered Ktrans and ADC image voxels to generate spatial habitats and extract quantitative image features. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were used to evaluate IDH predictive performance. Multivariable logistic regression models were constructed and validated using leave-one-out cross-validation, and the contrast-enhanced subgroup was analyzed independently. Kaplan-Meier and Cox proportional hazards regression analyses were used to investigate the relationship between tumor habitats and progression-free survival (PFS) in the two IDH groups.

RESULTS

Three habitats were identified: Habitat 1 (hypo-vasopermeability and hyper-cellularity), Habitat 2 (hypo-vasopermeability and hypo-cellularity), and Habitat 3 (hyper-vasopermeability). Compared to the IDH wild-type group, the IDH mutant group exhibited lower mean Ktrans values in Habitats 1 and 2 (both P < 0.001), higher volume (P < 0.05) and volume percentage (pVol, P < 0.01) of Habitat 2, and lower volume and pVol of Habitat 3 (both P < 0.001). The optimal logistic regression model for IDH prediction yielded an AUC of 0.940 (95% confidence interval [CI]: 0.880-1.000), which improved to 0.948 (95% CI: 0.890-1.000) after cross-validation. Habitat 2 contributed the most to the model, consistent with the findings in the contrast-enhanced subgroup. In IDH wild-type group, pVol of Habitat 2 was identified as a significant risk factor for PFS (high- vs. low-pVol subgroup, hazard ratio = 2.204, 95% CI: 1.061-4.580, P = 0.034), with a value below 0.26 indicating a 5-month median survival benefit.

CONCLUSIONS

Habitat imaging employing DCE-MRI and DWI may facilitate the characterization of ITH in adult-type diffuse gliomas and serve as a valuable adjunct in the preoperative prediction of IDH genotypes and prognosis.

CLINICAL TRIAL NUMBER

Not applicable.

HSPA5-mediated glioma hypoxia tolerance promotes M2 macrophage polarization under hypoxic microenvironment

BACKGROUND

The tumor microenvironment (TME), with hallmark features of hypoxia and immunosuppression, plays a crucial role in the progression of various solid tumors. However, the intricate interplay between tumor hypoxia and the formation of tumor immune microenvironment in glioma remains incompletely understood.

METHODS

In the present study, we initially identified genes associated with tumor hypoxia and the immune microenvironment through GSEA and IMMPORT database analysis. We subsequently identified hypoxia- and immune-related genes associated with glioma prognosis through further cross-analysis and multidatabase integrated analysis. HSPA5 was ultimately identified as a potential target gene related to the formation of the hypoxic microenvironment and immune microenvironment in glioma. Furthermore, we conducted MTT, colony formation, EdU, migration and invasion assays and intracranial orthotopic tumor model analysis to further evaluate the impact of interfering with HSPA5 expression on the hypoxic and immune microenvironments of glioma.

RESULTS

We found that HSPA5 is highly expressed in glioma cells and tissues and is associated with a poor prognosis. Further investigation revealed that hypoxia promotes the malignant biological characteristics of glioma and reshaping the Immunosuppressive phenotype of tumor-associated macrophages (TAMs) through upregulation of the HIF-1α/HSPA5 axis. Silencing HSPA5 alleviated glioma hypoxia tolerance and induced the polarization of TAMs toward the M1 phenotype. The induced macrophages could exhibit a tumor-suppressive effect.

CONCLUSION

These observations suggest that HSPA5 upregulation promotes glioma progression by inducing hypoxia tolerance and reshaping the Immunosuppressive phenotype of TAMs. Therefore, targeting HSPA5 may be a novel therapeutic strategy for glioma.

Gastric Cancer Models Developed via GelMA 3D Bioprinting Accurately Mimic Cancer Hallmarks, Tumor Microenvironment Features, and Drug Responses

Current in vitro models for gastric cancer research, such as 2D cell cultures and organoid systems, often fail to replicate the complex extracellular matrix (ECM) found in vivo. For the first time, this study utilizes a gelatin methacryloyl (GelMA) hydrogel, a biomimetic ECM-like material, in 3D bioprinting to construct a physiologically relevant gastric cancer model. GelMA's tunable mechanical properties allow for the precise manipulation of cellular behavior within physiological ranges. Genetic and phenotypic analyses indicate that the 3D bioprinted GelMA (3Db) model accurately mimics the clinical tumor characteristics and reproduces key cancer hallmarks, such as cell proliferation, invasion, migration, angiogenesis, and the Warburg effect. Comparisons of gene expression and drug responses between the 3Db model and patient-derived xenograft models, both constructed from primary gastric cancer cells, validate the model's clinical relevance. The ability of the 3Db model to closely simulate in vivo conditions highlights its crucial role in identifying treatment targets and predicting patient-specific responses, showcasing its potential in high-throughput drug screening and clinical applications. This study is the first to report the pivotal role of GelMA-based 3D bioprinting in advancing gastric cancer research and regenerative medicine.

The metastatic cascade through the lens of therapeutic inhibition

Metastasis is a main cause of cancer-related death, and a deeper understanding of the metastatic process will inform more targeted and mechanistic approaches that can abrogate challenges in treatment efficacy and toxicity. Several steps throughout the metastatic cascade, from angiogenesis to secondary tumor formation, offer specific vulnerabilities to therapies that can lead to the decline or cessation of metastatic progression. A deeper understanding of the metastatic cascade also allows combination systemic therapies to be used synergistically. In this review, we describe current treatment modalities in the context of multiple steps of the metastatic cascade. We highlight their mechanisms and present their efficacy across multiple cancers. This work also presents targets within the metastatic cascade in need of more research that can advance the landscape of treatments and lead to the goal of metastatic cancer remission.

Bi-exponential diffusion-weighted imaging for differentiating high-grade gliomas from solitary brain metastases: a VOI-based histogram analysis

This study investigated the use of bi-exponential diffusion-weighted imaging (DWI) combined with structural features to differentiate high-grade glioma (HGG) from solitary brain metastasis (SBM). A total of 57 patients (31 HGG, 26 SBM) who underwent pre-surgical multi-b DWI and structural MRI (T1W, T2W, T1W + C) were included. Volumes of interest (VOI) in the peritumoral edema area (PTEA) and enhanced tumor area (ETA) were selected for analysis. Histogram features of slow diffusion coefficient (Dslow), fast diffusion coefficient (Dfast), and perfusion fraction (frac) were extracted. Results showed that HGG patients had higher skewness of Dfast (P = 0.022) and frac (P = 0.077), higher kurtosis of Dslow (P = 0.019) and frac (P = 0.025), and lower entropy of Dslow (P = 0.005) and frac (P = 0.001) within the ETA. Additionally, HGG exhibited lower mean frac in both ETA (P = 0.007) and PTEA (P = 0.017). Combining skewness of frac in ETA with clear tumor margin enhanced diagnostic performance, achieving an optimal AUC of 0.79. These findings suggest that histogram analysis of diffusion and perfusion characteristics in ETA and structural features can effectively differentiate HGG from SBM.

Potential of Natural Products in the Treatment of Glioma: Focus on Molecular Mechanisms

Despite the waning of traditional treatments for glioma due to possible long-term issues, the healing possibilities of substances derived from nature have been reignited in the scientific community. These natural substances, commonly found in fruits and vegetables, are considered potential alternatives to pharmaceuticals, as they have been shown in prior research to impact pathways surrounding cancer progression, metastases, invasion, and resistance. This review will explore the supposed molecular mechanisms of different natural components, such as berberine, curcumin, coffee, resveratrol, epigallocatechin-3-gallate, quercetin, tanshinone, silymarin, coumarin, and lycopene, concerning glioma treatment. While the benefits of a balanced diet containing these compounds are widely recognized, there is considerable scope for investigating the efficacy of these natural products in treating glioma.

Bioinformatic analysis constructs an optimal prognostic index for survival-related variables (OPISV) based on whole-genome expression data in Glioblastoma

PURPOSE

Using clinical information and transcriptomic sequencing data from glioblastoma (GBM) patients in the TCGA database to perform gene-by-gene analysis that is aligned with individual patient characteristics and develop an optimal prognostic index of survival-related variables (OPISV) through iterative machine learning techniques to predict the prognosis of GBM patients.

STUDY DESIGN

The TCGA dataset was utilized as the training dataset, while two GEO datasets served as independent validation cohorts. Initially, survival analysis (p < 0.001***), differential gene expression analysis (p < 0.05*), and univariate Cox regression analysis (p < 0.05*) were employed to identify genes that are highly correlated with patient prognosis and exhibit significant differences in survival status. Subsequently, incorporating the non-excludable variable of age, a multivariate Cox regression analysis was performed in a stepwise manner to construct the OPISV. Finally, logistic and LASSO regressions were used to validate the association between the identified genes and patient survival. The OPISV performance is evaluated and its potential mechanisms are explored.

RESULTS

Age, CTSD, PTPRN, PTPRN2, NSUN5, DNAJC30 and SOX21 emerged as the optimal variables through multivariate Cox regression iterations. Further analysis characterized Age, PTPRN and DNAJC30 as independent prognostic risk factors for constructing OPISV, which is validated with external GEO datasets and GEPIA database. In OPISV_high populations, significantly upregulated GABAergic synapse function was exposed. Differential genes identified from gene clustering of the GABAergic synapse pathway and gene module highly correlated with GABAergic synapse in the WGCNA analysis are pointing unequivocally to the glioma progress.

CONCLUSION

OPISV is feasible for predicting patient survival, as it may serve as a potential mechanism underlying the involvement of GABAergic synapses in the progression of GBM.

Profiling hypoxia signaling reveals a lncRNA signature contributing to immunosuppression in high-grade glioma

Background

Hypoxic conditions in glioma are linked to tumor aggressiveness, poor prognosis, and treatment resistance. Long non-coding RNAs (lncRNAs) play key roles in the hypoxic and immune microenvironment of cancers, but their link to hypoxia-induced immunosuppression in high-grade glioma (HGG) is not well-studied.

Methods

Gene expression profiles from TCGA and CGGA, along with clinical and genomic data, were analyzed. Bioinformatics methods including Consensus Clustering, Pearson correlation, and Cox regression analyses were used. Cell proliferation was assessed using cell counting kit-8 and colony formation assays. Glioma-macrophage interactions were evaluated using a co-culture model.

Results

Hypoxia subtype clustering showed hypoxic stress correlates with worse HGG prognosis. Eight hypoxia-related lncRNAs (AP000695.4, OSMR-AS1, AC078883.3, RP11-545E17.3, LINC01057, LINC01503, TP73-AS1, and LINC00672) with prognostic value were identified, forming a risk signature that separated patients into distinct prognostic groups. Multivariate Cox regression confirmed the signature as an independent prognostic factor. High-risk patients had greater hypoxia, leading to an immunosuppressive environment and immunotherapy resistance via tumor-associated macrophages (TAMs). TP73-AS1 significantly influenced hypoxia-induced TAM infiltration and M2 polarization.

Conclusions

We profiled hypoxic stress in HGG and developed an 8-lncRNA hypoxia-related signature predicting patient survival and immunotherapy response, emphasizing its role in hypoxia-induced immunosuppression.

Soloxolone para-methylanilide effectively suppresses aggressive phenotype of glioblastoma cells including TGF-β1-induced glial-mesenchymal transition in vitro and inhibits growth of U87 glioblastoma xenografts in mice

Soloxolone amides are semisynthetic triterpenoids that can cross the blood-brain barrier and inhibit glioblastoma growth both in vitro and in vivo. Here we investigate the impact of these compounds on processes associated with glioblastoma invasiveness and therapy resistance. Screening of soloxolone amides against glioblastoma cells revealed the ability of compound 7 (soloxolone para-methylanilide) to inhibit transforming growth factor-beta 1 (TGF-β1)-induced glial-mesenchymal transition Compound 7 inhibited morphological changes, wound healing, transwell migration, and expression of mesenchymal markers (N-cadherin, fibronectin, Slug) in TGF-β1-induced U87 and U118 glioblastoma cells, while restoring their adhesiveness. Confocal microscopy and molecular docking showed that 7 reduced SMAD2/3 nuclear translocation probably by direct interaction with the TGF-β type I and type II receptors (TβRI/II). In addition, 7 suppressed stemness of glioblastoma cells as evidenced by inhibition of colony forming ability, spheroid growth, and aldehyde dehydrogenase (ALDH) activity. Furthermore, 7 exhibited a synergistic effect with temozolomide (TMZ) on glioblastoma cell viability. Using N-acetyl-L-cysteine (NAC) and flow cytometry analysis of Annexin V-FITC-, propidium iodide-, and DCFDA-stained cells, 7 was found to synergize the cytotoxicity of TMZ by inducing ROS-dependent apoptosis. Further in vivo studies showed that 7, alone or in combination with TMZ, effectively suppressed the growth of U87 xenograft tumors in mice. Thus, 7 demonstrated promising potential as a component of combination therapy for glioblastoma, reducing its invasiveness and increasing its sensitivity to chemotherapy.

[Establishment of an Engineered Bacterial Membrane Biomimetic Nanodrug Delivery System and Its Role in the Treatment of Glioma]

Objective

To develop engineered bacterial membrane biomimetic nanoparticles, Angiopep-2 E. coli membrane (ANG-2 EM)@PDA-PEI-CpG (ANG-2 EM@PPC), for efficient targeted drug delivery in the treatment of glioma, and to provide theoretical and technical support for targeted glioma therapy.

Methods

The expression of inaX-N-angiopep-2 engineered bacteria was constructed in the laboratory, and ANG-2 EM was obtained through lysozyme treatment and ultrafiltration centrifugation. ANG-2 EM@PPC was prepared by ultrasonication of bacterial membranes. Western blotting, agarose gel electrophoresis, and transmission electron microscopy (TEM) were used to verify the preparation. Particle size and Zeta potential were measured to investigate the stability of ANG-2 EM@PPC. Regarding cell experiments, CCK-8 assay was performed to determine the effect of ANG-2 EM@PPC on the survival rate of neutrophils. A flow chamber model was designed and constructed, and the uptake efficiency of neutrophils was measured by flow cytometry to investigate the hitchhiking efficiency of ANG 2 EM@PPC on neutrophils in inflammatory environment. Neutrophil death patterns were characterized by fluorescence microscopy, and flow cytometry and Western blotting were performed to examine neutrophil apoptotic bodies and the proportion of apoptotic bodies produced. Regarding animal experiments, a mouse model of in situ glioma was established and the inflammatory environment of tumor tissue was verified. The tumor model mice were divided into three groups, including DiR group, EM@PPC group, and ANG-2 EM@PPC group (all n=3), which were injected with DiR, ANG-2 EM@PDA-PEI-CpG, and EM@PDA-PEI-CpG via the tail vein, respectively (all at 10 mg/kg). Fluorescence images of organs and the brain were used to examine the distribution of the three formulations in vivo and in the brain. The tumor model mice were further divided into PBS group, PDA group, PC group, PPC group, EM@PPC group, and ANG-2 EM@PPC group (all n=4), which were injected with PBS, PDA, PC, PPC, EM@PPC, and ANG-2 EM@PPC injected via the tail vein, respectively (all at 10 mg/kg). Imaging was performed in vivo to observe tumor regression, and the survival rate and body mass of mice were measured to evaluate in vivo pharmacodynamics. TUNEL staining (brain tissue) and HE staining (brain, heart, liver, spleen, lung and kidney tissues) were performed to evaluate the therapeutic effect.

Results

The results of TEM showed successful preparation of engineered bacterial membrane biomimetic nanoparticles, with PPC exhibiting a distinct shell-core structure and a shell thickness of about 8.2 nm. Due to the coating of ANG-2 EM, the shell thickness of ANG-2 EM@PPC increased to about 9.6 nm, with a clear bacterial membrane layer on the surface. Stability was maintained for at least one week. ANG-2 EM@PPC had no significant effect on the activity of neutrophils according to the findings from the CCK-8 assay. Flow cytometry showed that ANG-2 EM@PPC uptake is enhanced in activated neutrophils and hitchhiking on neutrophils was more efficient in the stationary state than that in the flowing condition. Compared with the EM@PPC group, the neutrophil hitchhiking ability of the ANG-2 EM@PPC group was enhanced (uptake efficiency 24.9% vs. 31.1%). Fluorescence microscopy showed that ANG-2 EM@PPC changed the death pathway of neutrophils from neutrophil extracellular traps-osis (NETosis) to apoptosis. Western blot confirmed the production of neutrophil apoptotic bodies, and flow cytometry showed that the production rate was as high as 77.7%. Animal experiments showed that there was no significant difference in the distribution of engineered bacterial membrane biomimetic nanoparticles in the organs (heart, liver, spleen, lungs, and kidney) in the DiR group, the EM@PPC gropu, and the ANG-2 EM@PPC group (P>0.05), but there was higher distribution in the brain tissue in EM@PPC and ANG-2 EM@PPC groups compared to the DiR group (P<0.05). Engineered bacterial membrane biomimetic nanoparticles crossed the blood-brain barrier (BBB), and exhibited high affinity to and internalization by neutrophils located in brain tumors. Compared with PBS, PDA, PC, and PPC groups, the survival rate and body mass of mice in the EM@PPC group were improved, tumor fluorescence intensity was weakened, and apoptotic cells were increased. These trends were even more prominent in the ANG-2 EM@PPC group. No abnormality was found in the HE staining of any group.

Conclusion

An ANG-2 EM@PPC nanodelivery system with inflammation response characteristics was successfully prepared, capable of crossing BBB and targeting the tumor inflammatory microenvironment to improve the anti-glioma efficacy. This study provides a new drug delivery strategy for glioma treatment and offers a new idea for targeted drug delivery in the non-invasive inflammatory microenvironments in other central nervous system diseases.

Differentiation of glioma and solitary brain metastasis: a multi-parameter magnetic resonance imaging study using histogram analysis

BACKGROUND

Differentiation of glioma and solitary brain metastasis (SBM), which requires biopsy or multi-disciplinary diagnosis, remains sophisticated clinically. Histogram analysis of MR diffusion or molecular imaging hasn't been fully investigated for the differentiation and may have the potential to improve it.

METHODS

A total of 65 patients with newly diagnosed glioma or metastases were enrolled. All patients underwent DWI, IVIM, and APTW, as well as the T1W, T2W, T2FLAIR, and contrast-enhanced T1W imaging. The histogram features of apparent diffusion coefficient (ADC) from DWI, slow diffusion coefficient (Dslow), perfusion fraction (frac), fast diffusion coefficient (Dfast) from IVIM, and MTRasym@3.5ppm from APTWI were extracted from the tumor parenchyma and compared between glioma and SBM. Parameters with significant differences were analyzed with the logistics regression and receiver operator curves to explore the optimal model and compare the differentiation performance.

RESULTS

Higher ADCkurtosis (P = 0.022), frackurtosis (P<0.001),and fracskewness (P<0.001) were found for glioma, while higher (MTRasym@3.5ppm)10 (P = 0.045), frac10 (P<0.001),frac90 (P = 0.001), fracmean (P<0.001), and fracentropy (P<0.001) were observed for SBM. frackurtosis (OR = 0.431, 95%CI 0.256-0.723, P = 0.002) was independent factor for SBM differentiation. The model combining (MTRasym@3.5ppm)10, frac10, and frackurtosis showed an AUC of 0.857 (sensitivity: 0.857, specificity: 0.750), while the model combined with frac10 and frackurtosis had an AUC of 0.824 (sensitivity: 0.952, specificity: 0.591). There was no statistically significant difference between AUCs from the two models. (Z = -1.14, P = 0.25).

CONCLUSIONS

The frac10 and frackurtosis in enhanced tumor region could be used to differentiate glioma and SBM and (MTRasym@3.5ppm)10 helps improving the differentiation specificity.

Sexual-biased necroinflammation is revealed as a predictor of bevacizumab benefit in glioblastoma

BACKGROUND

Glioblastoma (GBM) is a highly malignant brain tumor that affects men more often than women. In addition, the former shows a poorer survival prognosis. To date, the reason for this sex-specific aggressiveness remains unclear. Therefore, the aim of this study is to investigate tumor processes that explain these sex differences.

METHODS

This was a retrospective study of GBM patients which was stratified according to sex. A cohort with 73 tumors was analyzed with immunohistochemistry, RNA-seq and RT-qPCR to characterize differences in vascular and immunological profiles. Transcriptomic profiling, gene set enrichment analysis, and pathway enrichment analysis were used for discovering molecular pathways predominant in each group. We further investigated the therapeutic effect of bevacizumab (vascular endothelial growth factor A (VEGFA) blocking antibody) in a retrospective GBM cohort (36 tumors) based on sex differences.

RESULTS

We found that under hypoxic tumor conditions, 2 distinct tumor immuno-angiogenic ecosystems develop linked to sex differences and ESR1 expression is generated. One of these subgroups, which includes male patients with low ESR1 expression, is characterized by vascular fragility associated with the appearance of regions of necrosis and high inflammation (called necroinflamed tumors). This male-specific tumor subtype shows high inflammation related to myeloid-derived suppressor cells infiltration. Using this stratification, we identified a possible group of patients who could respond to bevacizumab (BVZ) and revealed a genetic signature that may find clinical applications as a predictor of those who may benefit most from this treatment.

CONCLUSIONS

This study provides a stratification based on the sexual differences in GBM, which associates the poor prognosis with the presence of immunosuppressive myeloid cells in the necrotic areas. This new stratification could change the current prognosis of GBM and identifies those who respond to BVZ treatment.

Programmed cell death disrupts inflammatory tumor microenvironment (TME) and promotes glioblastoma evolution

Glioblastoma (GBM) is the most common malignant brain tumor and has a dismal prognosis even under the current first-line treatment, with a 5-year survival rate less than 7%. Therefore, it is important to understand the mechanism of treatment resistance and develop new anti-tumor strategies. Induction of programmed cell death (PCD) has become a promising anti-tumor strategy, but its effectiveness in treating GBM remains controversial. On the one hand, PCD triggers tumor cell death and then release mediators to draw in immune cells, creating a pro-inflammatory tumor microenvironment (TME). One the other hand, mounting evidence suggests that PCD and inflammatory TME will force tumor cells to evolve under survival stress, leading to tumor recurrence. The purpose of this review is to summarize the role of PCD and inflammatory TME in the tumor evolution of GBM and promising methods to overcome tumor evolution.

Enhancing CAR-T cell metabolism to overcome hypoxic conditions in the brain tumor microenvironment

The efficacy of chimeric antigen receptor T cell (CAR-T) therapy has been limited against brain tumors to date. CAR-T cells infiltrating syngeneic intracerebral SB28 EGFRvIII gliomas revealed impaired mitochondrial ATP production and a markedly hypoxic status compared with ones migrating to subcutaneous tumors. Drug screenings to improve metabolic states of T cells under hypoxic conditions led us to evaluate the combination of the AMPK activator metformin and the mTOR inhibitor rapamycin (Met+Rap). Met+Rap-pretreated mouse CAR-T cells showed activated PPAR-γ coactivator 1α (PGC-1α) through mTOR inhibition and AMPK activation, and a higher level of mitochondrial spare respiratory capacity than those pretreated with individual drugs or without pretreatment. Moreover, Met+Rap-pretreated CAR-T cells demonstrated persistent and effective antiglioma cytotoxic activities in the hypoxic condition. Furthermore, a single intravenous infusion of Met+Rap-pretreated CAR-T cells significantly extended the survival of mice bearing intracerebral SB28 EGFRvIII gliomas. Mass cytometric analyses highlighted increased glioma-infiltrating CAR-T cells in the Met+Rap group, with fewer Ly6c+CD11b+ monocytic myeloid-derived suppressor cells in the tumors. Finally, human CAR-T cells pretreated with Met+Rap recapitulated the observations with murine CAR-T cells, demonstrating improved functions under in vitro hypoxic conditions. These findings advocate for translational and clinical exploration of Met+Rap-pretreated CAR-T cells in human trials.

Molecular diversity in isocitrate dehydrogenase-wild-type glioblastoma

In the dynamic landscape of glioblastoma, the 2021 World Health Organization Classification of Central Nervous System tumours endeavoured to establish biological homogeneity, yet isocitrate dehydrogenase-wild-type (IDH-wt) glioblastoma persists as a tapestry of clinical and molecular diversity. Intertumoural heterogeneity in IDH-wt glioblastoma presents a formidable challenge in treatment strategies. Recent strides in genetics and molecular biology have enhanced diagnostic precision, revealing distinct subtypes and invasive patterns that influence survival in patients with IDH-wt glioblastoma. Genetic and molecular biomarkers, such as the overexpression of neurofibromin 1, phosphatase and tensin homolog and/or cyclin-dependent kinase inhibitor 2A, along with specific immune cell abundance and neurotransmitters, correlate with favourable outcomes. Conversely, increased expression of epidermal growth factor receptor tyrosine kinase, platelet-derived growth factor receptor alpha and/or vascular endothelial growth factor receptor, coupled with the prevalence of glioma stem cells, tumour-associated myeloid cells, regulatory T cells and exhausted effector cells, signifies an unfavourable prognosis. The methylation status of O6-methylguanine-DNA methyltransferase and the influence of microenvironmental factors and neurotransmitters further shape treatment responses. Understanding intertumoural heterogeneity is complemented by insights into intratumoural dynamics and cellular interactions within the tumour microenvironment. Glioma stem cells and immune cell composition significantly impact progression and outcomes, emphasizing the need for personalized therapies targeting pro-tumoural signalling pathways and resistance mechanisms. A successful glioblastoma management demands biomarker identification, combination therapies and a nuanced approach considering intratumoural variability. These advancements herald a transformative era in glioblastoma comprehension and treatment.

Identifying PLAUR as a Pivotal Gene of Tumor Microenvironment and Regulating Mesenchymal Phenotype of Glioblastoma

The mesenchymal (MES) phenotype of glioblastoma (GBM) is the most aggressive and therapy-resistant subtype of GBM. The MES phenotype transition during tumor progression results from both tumor-intrinsic genetic alterations and tumor-extrinsic microenvironmental factors. In this study, we sought to identify genes that can modulate the MES phenotype via both mechanisms. By integrating weighted gene co-expression network analysis (WGCNA) and the differential expression analysis of hypoxia-immunosuppression-related genes, we identified the plasminogen activator, urokinase receptor (PLAUR) as the hub gene. Functional enrichment analysis and GSVA analysis demonstrated that PLAUR was associated with the MES phenotype of glioma and the hypoxia-immunosuppression-related microenvironmental components. Single-cell sequencing analysis revealed that PLAUR mediated the ligand-receptor interaction between tumor-associated macrophages (TAMs) and glioma cells. Functional experiments in vitro with cell lines or primary glioma cells and xenograft models using BALB/c nude mice confirmed the role of PLAUR in promoting the MES phenotype of GBM. Our findings indicate that PLAUR regulates both glioma cells and tumor cell-extrinsic factors that favor the MES phenotype and suggest that PLAUR might be a potential target for GBM therapy.

Immune Assessment Today: Optimizing and Standardizing Efforts to Monitor Immune Responses in Cancer and Beyond

As part of a symposium, current and former directors of Immune Monitoring cores and investigative oncologists presented insights into the past, present and future of immune assessment. Dr. Gnjatic presented a classification of immune monitoring technologies ranging from universally applicable to experimental protocols, while emphasizing the need for assay harmonization. Dr. Obeng discussed physiologic differences among CD8 T cells that align with anti-tumor responses. Dr. Lyerly presented the Soldano Ferrone lecture, commemorating the passionate tumor immunologist who inspired many, and covered a timeline of monitoring technology development and its importance to immuno-oncology. Dr. Sonabend presented recent achievements in glioblastoma treatment, accentuating the range of monitoring techniques that allowed him to refine patient selection for clinical trials. Dr. Guevara-Patiño focused on hypoxia within the tumor environment and stressed that T cell viability is not to be confused with functionality. Dr. Butterfield accentuated monitoring of dendritic cell metabolic (dys)function as a determinant for tumor vaccine success. Lectures were interspersed with select abstract presentations. To summarize the concepts, Dr. Maecker from Stanford led an informative forum discussion, pointing towards the future of immune monitoring. Immune monitoring continues to be a guiding light towards effective immunotherapeutic strategies.

Myeloid cell-derived creatine in the hypoxic niche promotes glioblastoma growth

Glioblastoma (GBM) is a malignancy dominated by the infiltration of tumor-associated myeloid cells (TAMCs). Examination of TAMC metabolic phenotypes in mouse models and patients with GBM identified the de novo creatine metabolic pathway as a hallmark of TAMCs. Multi-omics analyses revealed that TAMCs surround the hypoxic peri-necrotic regions of GBM and express the creatine metabolic enzyme glycine amidinotransferase (GATM). Conversely, GBM cells located within these same regions are uniquely specific in expressing the creatine transporter (SLC6A8). We hypothesized that TAMCs provide creatine to tumors, promoting GBM progression. Isotopic tracing demonstrated that TAMC-secreted creatine is taken up by tumor cells. Creatine supplementation protected tumors from hypoxia-induced stress, which was abrogated with genetic ablation or pharmacologic inhibition of SLC6A8. Lastly, inhibition of creatine transport using the clinically relevant compound, RGX-202-01, blunted tumor growth and enhanced radiation therapy in vivo. This work highlights that myeloid-to-tumor transfer of creatine promotes tumor growth in the hypoxic niche.

Potential roles for efferocytosis in glioblastoma immune evasion

Glioblastoma is an aggressive and incurable brain cancer. This cancer establishes both local and systemic immunosuppression that creates a major obstacle to effective immunotherapies. Many studies point to tumor-resident myeloid cells (primarily microglia and macrophages) as key mediators of this immunosuppression. Myeloid cells exhibit a high level of plasticity with respect to their phenotype and are capable of both stimulating and repressing immune responses. How glioblastomas recruit myeloid cells and exploit them to avoid the immune system is an active area of research. Macrophages can acquire an immunosuppressive phenotype as a consequence of exposure to cytokines such as TGFB1 or IL4; in addition, macrophages can acquire an immunosuppressive phenotype as a consequence of the engulfment of apoptotic cells, a process referred to as efferocytosis. There is substantial evidence that glioblastoma cells are able to secrete cytokines and other factors that induce an immunosuppressive phenotype in macrophages and microglia. However, less is known about the contribution of efferocytosis to immunosuppression in glioblastoma. Here I review the literature in this area and discuss the potential of efferocytosis inhibition to improve glioblastoma response to immunotherapy.

IFN-γ Triggered IFITM2 Expression to Induce Malignant Phenotype in Elderly GBM

Advanced age is an important risk factor for the worse clinical presentation of gliomas, especially glioblastoma (GBM). The tumor microenvironment (TME) in elderly GBM (eGBM) patients is considerably different from that in young ones, which causes the inferior clinical outcome. Based on the data from the Chinese Glioma Genome Atlas RNA sequence (CGGA RNA-seq), the Cancer Genome Atlas RNA array (TCGA RNA-array), and gene set enrichment (GSE) 16011 array sets, the differential genes and function between eGBM (≥ 60 years old) and young GBM (yGBM, 20-60 years old) groups were explored. Immunohistochemistry (IHC) was utilized to depict the abundance of CD8+ cells (the main resource of IFN-γ) and IFITM2 protein expression in GBM samples. Furthermore, reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting (WB) were performed to verify the link between IFN-γ and IFITM2. Moreover, the small-interfering RNA (siRNA) of IFITM2 was used to explore the function of IFITM2 in GBM. Characterized by inflammatory TME and higher IFITM2 expression, eGBM harbored a shorter survival time. Chemotaxis and inflammatory cytokine-related genes were enriched in the eGBM group, with more infiltrative CD8+ T cells. The IHC of CD8 and IFITM2-staining could demonstrate these results. In addition, the IFN-γ response pathway was activated in eGBM and resulted in a dismal outcome. Next, it was found that IFITM2 triggered by IFN-γ played a key role in IFN-γ-induced malignant phenotype in eGBM.

Enhancing CAR-T Cell Metabolism to Overcome Hypoxic Conditions in the Brain Tumor Microenvironment

The efficacy of chimeric antigen receptor (CAR)-T therapy has been limited against brain tumors to date. CAR-T cells infiltrating syngeneic intracerebral SB28-EGFRvIII glioma revealed impaired mitochondrial ATP production and a markedly hypoxic status compared to ones migrating to subcutaneous tumors. Drug screenings to improve metabolic states of T cells under hypoxic conditions led us to evaluate the combination of AMPK activator Metformin and the mTOR inhibitor Rapamycin (Met+Rap). Met+Rap-pretreated mouse CAR-T cells showed activated PPAR-gamma coactivator 1α (PGC-1α) through mTOR inhibition and AMPK activation, and a higher level of mitochondrial spare respiratory capacity than those pretreated with individual drugs or without pretreatment. Moreover, Met+Rap-pretreated CAR-T cells demonstrated persistent and effective anti-glioma cytotoxic activities in the hypoxic condition. Furthermore, a single intravenous infusion of Met+Rap-pretreated CAR-T cells significantly extended the survival of mice bearing intracerebral SB28-EGFRvIII gliomas. Mass cytometric analyses highlighted increased glioma-infiltrating CAR-T cells in the Met+Rap group with fewer Ly6c+ CD11b+ monocytic myeloid-derived suppressor cells in the tumors. Finally, human CAR-T cells pretreated with Met+Rap recapitulated the observations with murine CAR-T cells, demonstrating improved functions in vitro hypoxic conditions. These findings advocate for translational and clinical exploration of Met+Rap-pretreated CAR-T cells in human trials.

Hsa_circRNA_0084043 promoting tumorigenesis in glioma through miR-577 sponging

Circular RNAs (circRNAs) are important non-coding RNAs (ncRNAs) involved in the development of multiple human diseases, especially cancers. circRNA_0084043 is significantly involved in the progression of melanoma. However, whether circRNA_0084043 is associated with glioma remains unknown. In this study, the upregulation of circRNA_0084043 in glioma and the association between circRNA_0084043 and glioma grade were identified. Our results showed that circRNA_0084043 is significantly involved in the proliferative, migratory, and invasive capacities of glioma cells. The results obtained from starBase, luciferase reporter assays, RNA immunoprecipitation assays, and RNA pull-down assays demonstrated that circRNA_0084043 acts as a direct sponge for miR-577. TargetScan algorithm was used to identify potential miR-577 targets, it was found that sorting nexin 5 (SNX5) is a candidate bound to miR-577. Finally, cell experiments testified that circRNA_0084043 enhanced growth, migration and invasion of glioma through the regulation of miR-577-mediated SNX5. Taken together, we concluded that circRNA_0084043 in the miR-577/SNX5 axis can be used as a candidate target for glioma therapy.

Intratumoral thrombosis as a histological biomarker for predicting epidermal growth factor receptor alteration and poor prognosis in patients with glioblastomas

PURPOSE

Intratumoral thrombosis is a specific finding in glioblastomas and considered the origin of palisading necrosis. Its distribution and contribution to the glioblastoma pathophysiology and systemic thrombosis are obscure, although deep vein thrombosis is a common complication in glioblastoma cases.

METHODS

Clinicopathological and genetic analyses were performed on 97 glioblastoma tissue specimens to elucidate the role of thrombotic events and associated molecular abnormalities.

RESULTS

Morphologically, intratumoral thrombosis was observed more frequently in vessels composed of single-layered CD34-positive endothelium and/or αSMA-positive pericytes in the tumor periphery, compared to microvascular proliferation with multi-channeled and pericyte-proliferating vessels in the tumor center. Intratumoral thrombosis was significantly correlated with the female sex, high preoperative D-dimer levels, and epidermal growth factor receptor (EGFR) amplification. The presence of one or more thrombi in 20 high-power fields was a predictive marker of EGFR amplification, with a sensitivity of 81.5% and specificity of 52.6%. RNA sequencing demonstrated that the group with many thrombi had higher EGFR gene expression levels than the group with few thrombi. The tumor cells invading along the vessels in the tumor periphery were positive for wild-type EGFR but negative for EGFRvIII, whereas the cells around the microvascular proliferation (MVP) in the tumor center were positive for both wild-type EGFR and EGFRvIII. Intratumoral thrombosis is an independent poor prognostic factor.

CONCLUSIONS

Aberrant but exquisitely regulated EGFR can induce thrombosis in non-MVP vessels in the tumor invasion area and then promote palisading necrosis, followed by hypoxia, abnormal angiogenesis, and further tumor cell invasion.

Imaging Spectrum of the Developing Glioblastoma: A Cross-Sectional Observation Study

Glioblastoma (GBM) has the typical radiological appearance (TRA) of a centrally necrotic, peripherally enhancing tumor with surrounding edema. The objective of this study was to determine whether the developing GBM displays a spectrum of imaging changes detectable on routine clinical imaging prior to TRA GBM. Patients with pre-operative imaging diagnosed with GBM (1 January 2014-31 March 2022) were identified from a neuroscience center. The imaging was reviewed by an experienced neuroradiologist. Imaging patterns preceding TRA GBM were analyzed. A total of 76 out of 555 (14%) patients had imaging preceding TRA GBM, 57 had solitary lesions, and 19 had multiple lesions (total = 84 lesions). Here, 83% of the lesions had cortical or cortical/subcortical locations. The earliest imaging features for 84 lesions were T2 hyperintensity/CT low density (n = 18), CT hyperdensity (n = 51), and T2 iso-intensity (n = 15). Lesions initially showing T2 hyperintensity/CT low density later showed T2 iso-intensity. When CT and MRI were available, all CT hyperdense lesions showed T2 iso-intensity, reduced diffusivity, and the following enhancement patterns: nodular 35%, solid 29%, none 26%, and patchy peripheral 10%. The mean time to develop TRA GBM from T2 hyperintensity was 140 days and from CT hyperdensity was 69 days. This research suggests that the developing GBM shows a spectrum of imaging features, progressing through T2 hyperintensity to CT hyperdensity, T2 iso-intensity, reduced diffusivity, and variable enhancement to TRA GBM. Red flags for non-TRA GBM lesions are cortical/subcortical CT hyperdense/T2 iso-intense/low ADC. Future research correlating this imaging spectrum with pathophysiology may provide insight into GBM growth patterns.

Expression of intra-tumoral necrosis-associated cytokine pattern correlated with prognosis and immune status in glioma

Intra-tumoral necrosis (ITN) is reported to be an independent prognostic factor in glioma. However, knowledge of ITN is mainly limited to pseudopalisadwe, while its other aspects were neglected. Therefore, a deeper understanding of ITN could be valuable for understanding its exact role in glioma. The only reliable ITN model was time-dependently achieved with the GL261 syngeneic mouse model. The ITN-associated expression pattern was enriched from RNA sequencing. TCGA glioma samples were clustered into a high-expression group (HEG) and a low-expression group (LEG) based on their pattern and their association with prognosis, clinical status, immune status, and therapeutic responsiveness were compared. Mouse glioma with ITN demonstrated invasive histology. Cytokine signaling was significantly enriched in necrotic mouse glioma compared with non-necrotic glioma tissues. Nine pro-inflammatory (IL6, PPBP, IL1A, TNFSF11, CXCL11, CXCL9, CXCL10, CXCL3, and CCL8) and two anti-inflammatory cytokine (IL1RN and IL10) genes were found to be related to ITN-associated cytokine patterns. Comparative analysis showed that HEG had a significantly shorter survival time, five differentially distributed clinical statuses, more infiltrated immune cells, greater expression of immune checkpoints, and better therapeutic responsiveness than LEG. In conclusion, the ITN-associated cytokine pattern is characteristically expressed in glioma with ITN and might indicate necrosis missed in histology diagnosis. Its expression pattern could predict the prognosis, tumor grade, immune status, and therapeutic responsiveness of glioma patients.

The coagulation-related genes for prognosis and tumor microenvironment in pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a malignancy characterized by challenging early diagnosis and poor prognosis. It is believed that coagulation has an impact on the tumor microenvironment of PDAC. The aim of this study is to further distinguish coagulation-related genes and investigate immune infiltration in PDAC.

METHODS

We gathered two subtypes of coagulation-related genes from the KEGG database, and acquired transcriptome sequencing data and clinical information on PDAC from The Cancer Genome Atlas (TCGA) database. Using an unsupervised clustering method, we categorized patients into distinct clusters. We investigated the mutation frequency to explore genomic features and performed enrichment analysis, utilizing Gene Ontology (GO) and Kyoto Encyclopedia of Genes (KEGG) to explore pathways. CIBERSORT was used to analyze the relationship between tumor immune infiltration and the two clusters. A prognostic model was created for risk stratification, and a nomogram was established to assist in determining the risk score. The response to immunotherapy was assessed using the IMvigor210 cohort. Finally, PDAC patients were recruited, and experimental samples were collected to validate the infiltration of neutrophils using immunohistochemistry. In addition, and identify the ITGA2 expression and function were identified by analyzing single cell sequencing data.

RESULTS

Two coagulation-related clusters were established based on the coagulation pathways present in PDAC patients. Functional enrichment analysis revealed different pathways in the two clusters. Approximately 49.4% of PDAC patients experienced DNA mutation in coagulation-related genes. Patients in the two clusters displayed significant differences in terms of immune cell infiltration, immune checkpoint, tumor microenvironment and TMB. We developed a 4-gene prognostic stratified model through LASSO analysis. Based on the risk score, the nomogram can accurately predict the prognosis in PDAC patients. We identified ITGA2 as a hub gene, which linked to poor overall survival (OS) and short disease-free survival (DFS). Single-cell sequencing analysis demonstrated that ITGA2 was expressed by ductal cells in PDAC.

CONCLUSIONS

Our study demonstrated the correlation between coagulation-related genes and the tumor immune microenvironment. The stratified model can predict the prognosis and calculate the benefits of drug therapy, thus providing the recommendations for clinical personalized treatment.

Macrophages in Recurrent Glioblastoma as a Prognostic Factor in the Synergistic System of the Tumor Microenvironment

Glioblastoma (GBM) is a common and highly malignant primary tumor of the central nervous system in adults. Ever more recent papers are focusing on understanding the role of the tumor microenvironment (TME) in affecting tumorigenesis and the subsequent prognosis. We assessed the impact of macrophages in the TME on the prognosis in patients with recurrent GBM. A PubMed, MEDLINE and Scopus review was conducted to identify all studies dealing with macrophages in the GBM microenvironment from January 2016 to December 2022. Glioma-associated macrophages (GAMs) act critically in enhancing tumor progression and can alter drug resistance, promoting resistance to radiotherapy and establishing an immunosuppressive environment. M1 macrophages are characterized by increased secretion of proinflammatory cytokines, such as IL-1ß, tumor necrosis factor (TNF), IL-27, matrix metalloproteinase (MMPs), CCL2, and VEGF (vascular endothelial growth factor), IGF1, that can lead to the destruction of the tissue. In contrast, M2 is supposed to participate in immunosuppression and tumor progression, which is formed after being exposed to the macrophage M-CSF, IL-10, IL-35 and the transforming growth factor-ß (TGF-β). Because there is currently no standard of care in recurrent GBM, novel identified targeted therapies based on the complex signaling and interactions between the glioma stem cells (GSCs) and the TME, especially resident microglia and bone-marrow-derived macrophages, may be helpful in improving the overall survival of these patients in the near future.

Local and systemic effects of IDH mutations on primary glioma patients

Adult gliomas are divided into isocitrate dehydrogenase (IDH) wild-type and IDH mutant subtypes according to the new 2021 World Health Organization classification system. However, the local and systemic effects of IDH mutations on primary glioma patients are not well illustrated. Retrospective analysis, immune-cell infiltration analysis, meta-analysis, and immunohistochemistry assay were applied in the present study. The results from our cohort showed that IDH mutant gliomas own a lower proliferating rate compared to that in wild-type gliomas. Patients with mutant IDH exhibited a higher frequency of seizures in both our cohort and the cohort from the meta-analysis. Mutations in IDH result in lower levels of intra-tumour but higher levels of circulating CD4+ and CD8+ T lymphocytes. Levels of neutrophils in both intra-tumour and circulating blood were lower in IDH mutant gliomas. Moreover, IDH mutant glioma patients receiving radiotherapy in combination with chemotherapy exhibited better overall survival with respect to radiotherapy alone. Mutations in IDH alters the local and circulating immune microenvironment, and increases the sensitivity of tumour cell to chemotherapy.

Anti-Vascular Endothelial Growth Factor Therapy Abolishes Glioma-Associated Endothelial Cell-Induced Tumor Invasion

Tumor-remodeled endothelial cells not only facilitate the formation of tumor angiogenesis but also promote tumorigenesis. In this study, we aimed to explore the interaction between glioma-associated endothelial cells (GAEs) and glioma cells. We found that different subtypes of glioma owned distinct GAE abundance. Glioma patients with high GAE abundance exhibited poor prognosis. Both the results of the bioinformatics analysis and the in vitro co-culture system assay revealed that GAE promoted glioma cell invasion. Besides, anti-vascular endothelial growth factor (VEGF) therapy partially abolished the effects of GAE on gliomas. Moreover, anti-VEGF therapy upregulated IL-2 expression in GAE, and exogenous IL-2 administration inhibits GAE-induced glioma cell invasion. Collectively, our present study provides a novel outstanding of the interaction between GAE and glioma cells.

Deciphering diffuse glioma immune microenvironment as a key to improving immunotherapy results

PURPOSE OF REVIEW

Immunotherapeutic approaches have yet to demonstrate their clinical efficacy in diffuse gliomas. Evidence is mounting that the central nervous system is subject to immune surveillance, but brain tumours manage to escape due to factors intrinsic to their tumoral immune microenvironment (TME). This review aims to discuss the recently characterized molecular bases of the glioma TME and the potentially actionable targets to improve immunotherapeutic results in these hard-to-treat cancers.

RECENT FINDINGS

Single-cell studies defined the composition of the glioma immune TME and its peculiarities compared with other solid cancers. In isocitrate dehydrogenase (IDH) wildtype gliomas, the TME is enriched in myeloid cells (monocyte-derived macrophages and resident microglia) with mainly immunosuppressive functions. Lymphocytes can infiltrate the glioma TME, but are exposed to multiple immunomodulating signals that render them in a state of deep exhaustion. IDH mutant gliomas produce the oncometabolite D-2-hydroxyglutarate with negative effects on leukocyte recruitment and function, resulting in the induction of an 'immune-desert' TME.

SUMMARY

Several molecular pathways have been recently identified in the induction of an 'immune-hostile' microenvironment in diffuse gliomas, unravelling potential vulnerabilities to targeted immunotherapies.

5-Hydroxymethylcytosines in circulating cell-free DNA reveal a diagnostic biomarker for glioma

Gliomas typically have unfavorable prognosis, due to late detection and interventions. However, effective biomarkers for early glioma diagnosis based on 5-hydroxymethylcytosines (5 hm C) in circulating cell-free DNA (cfDNA) are not currently available. 5 hm C profiles in GSE132118 set were subjected for establishment of diagnostic model using the LASSO (least absolute shrinkage and selection operator) algorithm. The 5 hm C-based models demonstrated great potency in differentiating healthy subjects from gliomas, with area under the curves (AUCs) > 0.91 in the training and validation sets. Moreover, the indicator performed well in combination with clinicopathological characteristics to differentiate glioblastomas (GBMs) from lower grade glioma (LGGs). Enrichment analysis on 5 hm C profiles displayed great correlation with glioma pathophysiology. The 5 hm C-derived biomarker might act as an effective and non-invasive measure in glioma screening.

Tumor Temperature: Friend or Foe of Virus-Based Cancer Immunotherapy

The temperature of a solid tumor is often dissimilar to baseline body temperature and, compared to healthy tissues, may be elevated, reduced, or a mix of both. The temperature of a tumor is dependent on metabolic activity and vascularization and can change due to tumor progression, treatment, or cancer type. Despite the need to function optimally within temperature-variable tumors, oncolytic viruses (OVs) are primarily tested at 37 °C in vitro. Furthermore, animal species utilized to test oncolytic viruses, such as mice, dogs, cats, and non-human primates, poorly recapitulate the temperature profile of humans. In this review, we discuss the importance of temperature as a variable for OV immunotherapy of solid tumors. Accumulating evidence supports that the temperature sensitivity of OVs lies on a spectrum, with some OVs likely hindered but others enhanced by elevated temperatures. We suggest that in vitro temperature sensitivity screening be performed for all OVs destined for the clinic to identify potential hinderances or benefits with regard to elevated temperature. Furthermore, we provide recommendations for the clinical use of temperature and OVs.

Neutrophils: New Critical Regulators of Glioma

In cancer, neutrophils are an important part of the tumour microenvironment (TME). Previous studies have shown that circulating and infiltrating neutrophils are associated with malignant progression and immunosuppression in gliomas. However, recent studies have shown that neutrophils have an antitumour effect. In this review, we focus on the functional roles of neutrophils in the circulation and tumour sites in patients with glioma. The mechanisms of neutrophil recruitment, immunosuppression and the differentiation of neutrophils are discussed. Finally, the potential of neutrophils as clinical biomarkers and therapeutic targets is highlighted. This review can help us gain a deeper and systematic understanding of the role of neutrophils, and provide new insights for treatment in gliomas.

Cell death in development, maintenance, and diseases of the nervous system

Cell death, be it of neurons or glial cells, marks the development of the nervous system. Albeit relatively less so than in tissues such as the gut, cell death is also a feature of nervous system homeostasis-especially in context of adult neurogenesis. Finally, cell death is commonplace in acute brain injuries, chronic neurodegenerative diseases, and in some central nervous system tumors such as glioblastoma. Recent studies are enumerating the various molecular modalities involved in the execution of cells. Intimately linked with cell death are mechanisms of disposal that remove the dead cell and bring about a tissue-level response. Heretofore, the association between these methods of dying and physiological or pathological responses has remained nebulous. It is envisioned that careful cartography of death and disposal may reveal novel understandings of disease states and chart new therapeutic strategies in the near future.