Glioblastoma evolution and heterogeneity from a 3D whole-tumor perspective

Immune cell targeting-mediated cytomimetic drug delivery system for BBB-penetrating and precise therapy of in situ glioma

Gliomas are a group of highly malignant tumors that are prone to recurrence after surgery. Due to the limitation of the blood-brain barrier (BBB), most antitumor drugs cannot cross it. Therefore, improving the delivery efficiency of antitumor drugs in their treatment remains a significant challenge. Herein, we report a unique cellular biomimetic drug delivery system (CTP@RAW) that benefits from the exceptional immune homing and long-term tracking ability of RAW 264.7 cells to specifically penetrate BBB and target tumor sites. The drug (TMZ) is encapsulated in RAW264.7 to avoid being cleared or degraded by the blood, improve bioavailability and reduce systemic toxicity. And that, owning to polydopamine (PDA) coating on the quantum dots-drug nanoparticles, which can endogenously and controllably release TMZ in response to certain tumor microenvironment (high GSH and low pH). This delivery system can also achieve precise localization and real-time visualization of tumors via fluorescence imaging. The released drugs effectively inhibit tumor growth by regulating cytokine expression levels, including GFAP, Ki67, Caspase-3, and TNF-α. Our study demonstrates that this drug delivery system can cross BBB, improve drug delivery efficiency, and has excellent potential for visualization and precision treatment of in situ gliomas.

Differentiating Glioma Recurrence and Pseudoprogression by APTw CEST MRI

OBJECTIVES

Recurrent glioma is highly treatment resistant due to its metabolic, cellular, and molecular heterogeneity and invasiveness. Tumor monitoring by conventional MRI has shortcomings to assess these key glioma characteristics. Recent studies introduced chemical exchange saturation transfer for metabolic imaging in oncology and assessed its diagnostic value for newly diagnosed glioma. This prospective study investigates amide proton transfer-weighted (APTw) MRI at 3 T as an imaging biomarker to elucidate the molecular heterogeneity and invasion patterns of recurrent glioma in comparison to pseudoprogression (PsPD).

MATERIALS AND METHODS

We performed a monocenter, prospective trial and screened 371 glioma patients who received tumor monitoring between August 2021 and March 2024 at our institution. The study included IDH wildtype astrocytoma and IDH mutant astrocytoma and oligodendroglioma, graded according to the WHO 2021 classification. Patients had received clinical standard of care treatment including surgical resection and radiochemotherapy prior to study inclusion. Patients were monitored by 3 monthly MRI follow-up imaging, and response assessment was performed according to the RANO criteria. Within this cohort, we identified 30 patients who presented with recurrent glioma and 12 patients with PsPD. In addition to standard anatomical sequences (FLAIR and T1-w Gd-enhanced sequences), MRI included APTw imaging. After sequence co-registration, semiautomated segmentation was performed of the FLAIR lesion, CE lesion, resection cavity, and the contralateral normal-appearing white matter, and APTw signals were quantified in these regions of interest.

RESULTS

APTw values were highest in solid, Gd-enhancing tumor parts as compared with the nonenhancing FLAIR lesion (APTw: 1.99% vs 1.36%, P = 0.001), whereas there were no detectable APTw alterations in the normal-appearing white matter (APTw: 0.005%, P < 0.001 compared with FLAIR). Patients with progressive disease had higher APTw levels compared with patients with PsPD (APTw: 1.99% vs 1.26%, P = 0.008). Chemical exchange saturation transfer identified heterogeneity within the FLAIR lesion that was not detectable by conventional sequences. There were also focal APTw signal peaks within contrast enhancing lesions as putative metabolic hotspots within recurrent glioma. The resection cavity developed an APTw increase at recurrence that was not detectable prior to recurrence nor in patients with PsPD (APTw before recurrence: 0.6% vs 2.68% at recurrence, P = 0.03).

CONCLUSIONS

Our study shows that APTw imaging can differentiate PD and PsPD. We identify previously undetectable imaging patterns during glioma recurrence, which include alterations within resection cavity associated with disease progression. Our work highlights the clinical potential of APTw imaging for glioma monitoring and further establishes it as an imaging biomarker in neuro-oncology.

Network pharmacology and in vitro experiments based strategy to explore the effects of Jujuboside A on the proliferation and migration ability of glioma cells

OBJECTIVE

This study predicted and verified the effects of Jujuboside A (JuA) on the proliferation and migration ability of glioma cells to developing new therapies for glioma treatment.

METHODS

The druggability of JuA was determined by using cheminformatics. Network pharmacology was used to analyse common targets, biological function and metabolic pathways of JuA against glioma. The core targets of JuA against glioma were validated by using molecular docking. The biological functions of JuA were verified by in vitro experiments.

RESULTS

Cheminformatics results showed that JuA is possible to be a drug. Network pharmacology revealed 294 shared targets between JuA and glioma, which were associated with proliferation, migration, and multiple signalling pathways. A total of 16 core targets related to the signalling pathways were verified by molecular docking. The in vitro experiments showed that JuA could inhibit cell proliferation and migration, decrease cell numbers and alter cell morphology.

CONCLUSION

The results of network pharmacology and in vitro experiments indicate that JuA has significant toxic effects on glioma cells, and can play a therapeutic role in treating glioma by inhibiting the proliferation and migration of glioma cells.

Genomic landscape of diffuse glioma revealed by whole genome sequencing

Diffuse gliomas are the commonest malignant primary brain tumour in adults. Herein, we present analysis of the genomic landscape of adult glioma, by whole genome sequencing of 403 tumours (256 glioblastoma, 89 astrocytoma, 58 oligodendroglioma; 338 primary, 65 recurrence). We identify an extended catalogue of recurrent coding and non-coding genetic mutations that represents a source for future studies and provides a high-resolution map of structural variants, copy number changes and global genome features including telomere length, mutational signatures and extrachromosomal DNA. Finally, we relate these to clinical outcome. As well as identifying drug targets for treatment of glioma our findings offer the prospect of improving treatment allocation with established targeted therapies.

Surface engineering of NIR-II luminescent gold nanoclusters for brain glioma-targeted imaging

Ultrasmall gold nanoclusters (AuNCs) with photoluminescence in the second near-infrared region (NIR-II) have emerged as promising probes for in vivo biomedical applications. However, it remains a challenge to utilize NIR-II-emitting AuNCs for imaging brain glioblastoma (GBM), which is highly lethal and hard to diagnose in time. Herein, we have presented systematic investigations on the brain delivery and GBM targeting efficacies of NIR-II-emitting AuNCs protected by different ligands. We first synthesized four types of AuNCs with surface coatings of small thiolated ligands and proteins, and then studied their in vitro penetration capability into the blood-brain barrier (BBB) and in vivo GBM targeting performances. It was found that the BBB permeability of AuNCs determined by the in vitro transwell model was not evidently affected by the surface ligands. Significantly, AuNCs protected by albumin exhibited notably extended blood circulation and less skull binding compared to those protected by small ligands, enabling superior in vivo brain GBM-targeted NIR-II PL imaging. We also modified the albumin-AuNCs with targeting peptides to improve in vivo imaging contrast. Additionally, AuNCs had negligible toxic effects on major organs as well as brain tissues and neurons, corroborating their good biocompatibility. This study examined the surface engineering of NIR-II luminescent AuNCs for brain GBM targeting, which may offer insights into the future design of AuNCs for bioapplications.

An Early Progression Biomarker in Glioblastoma: Microcirculatory Heterogeneity on Ultrasound Localization Microscopy

OBJECTIVE

Microcirculatory heterogeneity plays an essential role in the initiation and progression of glioblastoma (GBM). This study employs super-resolution ultrasound imaging to visualize the microcirculatory heterogeneity in GBM, with the objective of illustrating its predictive value in histological assessments.

METHODS

This in vivo study explored the microvasculature in GBM models using 15 Sprague-Dawley rats, divided into three groups based on tumor growth stages (12, 18 and 24 d post-implantation). Ultrasound localization microscopy (ULM) was employed to assess microvascular morphology, hemodynamics and heterogeneity. Structural, functional and heterogeneity parameters at different tumor growth stages were quantified using Kruskal-Wallis H tests, or analysis of variance, followed by Bonferroni correction to characterize tumor progression. Linear correlations between these quantitative parameters and pathological indicators, including histological vascular density (VD-H), proliferation index and histological vascular maturity index (VMI-H), were evaluated. A stepwise linear regression model was constructed to assess the predictive performance in relation to histological parameters.

RESULTS

Compared to histology, ULM enabled the earlier detection of tumor progression. The quantitative parameters derived from ULM provided a more comprehensive assessment than conventional metrics such as tumor size and immunohistochemistry. Multivariate analysis exhibited significant correlations among curvature, blood flow orientation variance (OV) and VD-H. Additionally, curvature, blood flow and OV demonstrated significant correlations with the proliferation index, while blood flow and fractal dimension showed significant associations with VMI-H. Heterogeneity parameters exhibited superior predictive power for certain histological features compared to microvascular morphology and functional perfusion.

CONCLUSION

ULM provides a basis for early, non-invasive in vivo imaging and quantification of microvascular structures in rat GBM and demonstrates super-resolution predictive capability for histological parameters.

Detection of Gene Fusions and Rearrangements in Formalin-Fixed, Paraffin-Embedded Solid Tumor Specimens Using High-Throughput Chromosome Conformation Capture

Chromosomal structural variants (SVs) are major contributors to cancer development. Although multiple methods exist for detecting SVs, they are limited in throughput, such as fluorescent in situ hybridization and targeted panels, and use RNA, which degrades in formalin-fixed, paraffin-embedded (FFPE) blocks and is unable to detect SVs that do not produce a fusion transcript. High-throughput chromosome conformation capture (Hi-C) is a DNA-based next-generation sequencing (NGS) method that preserves the spatial conformation of the genome, capturing long-range genetic interactions and SVs. Herein, a retrospective study analyzing 71 FFPE specimens from 10 different solid tumors was performed. Results showed high concordance (98%) with clinical fluorescent in situ hybridization and RNA NGS in detecting known SVs. Furthermore, Hi-C provided insight into the mechanism of SV formation, including chromothripsis and extrachromosomal DNA, and detected rearrangements between genes and regulatory regions, all of which are undetectable by RNA NGS. Lastly, SVs were detected in 71% of cases in which previous clinical methods failed to identify a driver. Of these, 14% were clinically actionable based on current medical guidelines, and an additional 14% were not in medical guidelines but involve targetable biomarkers. Current data suggest that Hi-C is a robust and accurate method for genome-wide SV analyses from FFPE tissue and can be incorporated into current clinical NGS workflows.

Brain-wide neuronal circuit connectome of human glioblastoma

Glioblastoma (GBM) infiltrates the brain and can be synaptically innervated by neurons, which drives tumour progression1,2. Synaptic inputs onto GBM cells identified so far are largely short range and glutamatergic3,4. The extent of GBM integration into the brain-wide neuronal circuitry remains unclear. Here we applied rabies virus-mediated and herpes simplex virus-mediated trans-monosynaptic tracing5,6 to systematically investigate circuit integration of human GBM organoids transplanted into adult mice. We found that GBM cells from multiple patients rapidly integrate into diverse local and long-range neural circuits across the brain. Beyond glutamatergic inputs, we identified various neuromodulatory inputs, including synapses between basal forebrain cholinergic neurons and GBM cells. Acute acetylcholine stimulation induces long-lasting elevation of calcium oscillations and transcriptional reprogramming of GBM cells into a more motile state via the metabotropic CHRM3 receptor. CHRM3 activation promotes GBM cell motility, whereas its downregulation suppresses GBM cell motility and prolongs mouse survival. Together, these results reveal the striking capacity for human GBM cells to rapidly and robustly integrate into anatomically diverse neuronal networks of different neurotransmitter systems. Our findings further support a model in which rapid connectivity and transient activation of upstream neurons may lead to a long-lasting increase in tumour fitness.

Gene regulatory networks analysis for the discovery of prognostic genes in gliomas

Gliomas are the most common and aggressive primary tumors of the central nervous system. Dysregulated transcription factors (TFs) and genes have been implicated in glioma progression, yet these tumors' overall structure of gene regulatory networks (GRNs) remains undefined. We analyzed transcriptional data from 989 primary gliomas in The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) to address this. GRNs were reconstructed using the RTN package which identifies regulons-sets of genes regulated by a common TF based on co-expression and mutual information. Regulon activity was evaluated through Gene Set Enrichment Analysis. Elastic net regularization and Cox regression identified 31 and 32 prognostic genes in the TCGA and CGGA datasets, respectively, with 11 genes overlapping, many of which are associated with neural development and synaptic processes. GAS2L3, HOXD13, and OTP demonstrated the strongest correlations with survival outcomes among these. Single-cell RNA-seq analysis of 201,986 cells revealed distinct expression patterns for these genes in glioma subpopulations, particularly oligoprogenitor cells. This study uncovers key GRNs and prognostic genes in gliomas, offering new insights into tumor biology and potential therapeutic targets.

Evolutionary paths towards metastasis

The evolution of metastasis in humans is considerably less well understood than the biology of early carcinogenesis. For over a century, clinicians and scientists have been debating whether metastatic potential is the intrinsic property of a cancer, pre-determined by the molecular characteristics of the tumour founder cell, or whether metastatic capacity evolves in a stepwise fashion as the tumour grows, akin to the multistage accumulation of oncogenic alterations that give rise to the first cancer cell. In this Perspective, I examine how genetic analyses of primary tumours and matched metastases can distinguish between these two competing metastasis evolution models, with particular emphasis on the utility of metastatic randomness - a quantitative measure that reflects whether metastases arise from a random selection of primary tumour subclones or whether they are enriched for descendants of privileged lineages that have acquired pro-metastatic traits. Probable metastasis evolution trajectories in tumours with high and low baseline metastatic capacity are discussed, along with the role of seeding rates and selection at different metastatic host sites. Finally, I argue that trailblazing insights into human metastasis biology are immediately possible if we make a concerted effort to apply existing experimental and theoretical tools to the right patient cohorts.

Current and Future Applications of 5-Aminolevulinic Acid in Neurosurgical Oncology

Maximal safe surgical resection is the gold standard in brain tumor surgery. Fluorescence-guided surgery (FGS) is one of many intraoperative techniques that have been designed with the intention of accomplishing this goal. 5-aminolevulinic acid (5-ALA) is one of the main fluorophores that facilitates FGS in neurosurgical oncology. Multiple different types of brain tumors can take in and metabolize 5-ALA into protoporphyrin IX (PpIX) through the mitochondria heme biosynthesis pathway. PpIX then selectively accumulates in brain tumor cells due to decreased ferrochelatase activity and emits red fluorescence (630-720 nm) when excited with blue light (375-440 nm). This mechanism allows neurosurgeons to better visualize tumor burden and increase extent of resection while preserving non-cancerous brain parenchyma and, specifically, eloquent white matter tracts, if combined with mapping techniques, thereby minimizing morbidity while improving survival. While 5-ALA use is well established in the treatment of high-grade gliomas, its applicability in recurrent high-grade and non-enhancing IDH-mutant low-grade gliomas, as well as non-glial tumors, is less established or limited by certain features of their cellular and molecular biology. This review aims to discuss the current landscape of 5-ALA utility across the diverse range of brain tumors, practical considerations that optimize its current use in neurosurgery, modern clinical limitations of 5-ALA, and how its application can be expanded by combining its use with other techniques that overcome current limitations.

Single-cell and spatial transcriptomic insights into glioma cellular heterogeneity and metabolic adaptations

Glioblastoma, one of the most aggressive and heterogeneous malignant tumors, presents significant challenges for clinical management due to its cellular and metabolic complexity. This review integrates recent advancements in single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics to elucidate glioblastoma's cellular heterogeneity and metabolic reprogramming. Diverse cellular subpopulations, including malignant proliferative cells, stem-like cells, mesenchymal-like cells, and immune-related cells, contribute to tumor progression, treatment resistance, and microenvironmental interactions. Spatial transcriptomics has further revealed distinct spatial distributions of these subpopulations, highlighting differences in metabolic activities between the tumor core and periphery. Key metabolic adaptations, such as enhanced glycolysis, fatty acid oxidation, and glutamine metabolism, play critical roles in supporting tumor growth, immune evasion, and therapeutic resistance. Targeting these metabolic pathways, especially in combination with immunotherapy, represents a promising avenue for glioblastoma treatment. This review emphasizes the importance of integrating single-cell and spatial multi-omics technologies to decode glioblastoma's metabolic landscape and explore novel therapeutic strategies. By addressing current challenges, such as metabolic redundancy and spatiotemporal dynamics, this work provides insights into advancing precision medicine for glioblastoma.

Three-dimensional regulatory hubs support oncogenic programs in glioblastoma

Dysregulation of enhancer-promoter communication in the three-dimensional (3D) nucleus is increasingly recognized as a potential driver of oncogenic programs. Here, we profiled the 3D enhancer-promoter networks of patient-derived glioblastoma stem cells to identify central regulatory nodes. We focused on hyperconnected 3D hubs and demonstrated that hub-interacting genes exhibit high and coordinated expression at the single-cell level and are associated with oncogenic programs that distinguish glioblastoma from low-grade glioma. Epigenetic silencing of a recurrent hub-with an uncharacterized role in glioblastoma-was sufficient to cause downregulation of hub-connected genes, shifts in transcriptional states, and reduced clonogenicity. Integration of datasets across 16 cancers identified "universal" and cancer-type-specific 3D hubs that enrich for oncogenic programs and factors associated with worse prognosis. Genetic alterations could explain only a small fraction of hub hyperconnectivity and increased activity. Overall, our study provides strong support for the potential central role of 3D regulatory hubs in controlling oncogenic programs and properties.

Single-Cell Profiling and Proteomics-Based Insights Into mTORC1-Mediated Angio+TAMs Polarization in Recurrent IDH-Mutant Gliomas

BACKGROUND

IDH mutant gliomas often exhibit recurrence and progression, with the mTORC1 pathway and tumor-associated macrophages potentially contributing to these processes. However, the precise mechanisms are not fully understood. This study seeks to investigate these relationships using proteomic, phosphoproteomic, and multi-dimensional transcriptomic approaches.

METHODS

This study established a matched transcriptomic, proteomic, and phosphoproteomic cohort of IDH-mutant gliomas with recurrence and progression, incorporating multiple glioma-related datasets. We first identified the genomic landscape of recurrent IDH-mutant gliomas through multi-dimensional differential enrichment, GSVA, and deconvolution analyses. Next, we explored tumor-associated macrophage subpopulations using single-cell sequencing in mouse models of IDH-mutant and wild-type gliomas, analyzing transcriptional changes via AddmodelScore and pseudotime analysis. We then identified these subpopulations in matched primary and recurrent IDH-mutant datasets, investigating their interactions with the tumor microenvironment and performing deconvolution to explore their contribution to glioma progression. Finally, spatial transcriptomics was used to map these subpopulations to glioma tissue sections, revealing spatial co-localization with mTORC1 and angiogenesis-related pathways.

RESULTS

Multi-dimensional differential enrichment, GSVA, and deconvolution analyses indicated that the mTORC1 pathway and the proportion of M2 macrophages are upregulated during the recurrence and progression of IDH-mutant gliomas. CGGA database analysis showed that mTORC1 activity is significantly higher in recurrent IDH-mutant gliomas compared to IDH-wildtype, with a correlation to M2 macrophage infiltration. KSEA revealed that AURKA is enriched during progression, and its inhibition reduces mTORC1 pathway activity. Single-cell sequencing in mouse models identified a distinct glioma subpopulation with upregulated mTORC1, exhibiting both M2 macrophage and angiogenesis transcriptional features, which increased after implantation of IDH-mutant tumor cells. Similarly, human glioma single-cell data revealed the same subpopulation, with cell-cell communication analysis showing active VEGF signaling. Finally, spatial transcriptomics deconvolution confirmed the co-localization of this subpopulation with mTORC1 and VEGFA in high-grade IDH-mutant gliomas.

CONCLUSIONS

Our findings suggest mTORC1 activation and Angio-TAMs play key roles in the recurrence and progression of IDH-mutant gliomas.

Challenges and Emerging Strategies of Immunotherapy for Glioblastoma

Glioblastoma (GBM) is recognized as the most lethal primary malignant tumor of the central nervous system. Although traditional treatments can somewhat prolong patient survival, the overall prognosis remains grim. Immunotherapy has become an effective method for GBM treatment. Oncolytic virus, checkpoint inhibitors, CAR T cells and tumor vaccines have all been applied in this field. Moreover, the combining of immunotherapy with traditional radiotherapy, chemotherapy, or gene therapy can further improve the treatment outcome. This review systematically summarizes the features of GBM, the recent progress of immunotherapy in overcoming GBM.

Current landscape and future directions of targeted-alpha-therapy for glioblastoma treatment

Glioblastoma (GB) is the most aggressive malignancy of the central nervous system. Despite two decades of intensive research since the establishment of the standard of care, emerging strategies have yet to produce consistent satisfactory outcomes. Because of its specific localisation and intricate characteristics, GB is a uniquely regulated solid tumour with a strong resistance to therapy. Advances in targeted radionuclide therapy (TRT), particularly with the introduction of a-emitting radionuclides, have unveiled potential avenues for the management of GB. Recent preclinical and clinical studies underscored promising advancements for targeted-α-therapy (TAT), but these therapeutic approaches exhibit a vast design heterogeneity, encompassing diverse radionuclides, vectors, target molecules, and administration modalities. This review seeks to critically assess the therapeutic landscape of GB through the perspective of TAT. Here, the focus is made on the advancements and limitations of in vivo explorations, pilot studies, and clinical trials, to determine the best directions for future investigations. In doing so, we hope to identify existing challenges and draw insights that might pave the way towards a more effective therapeutic approach.

Overcoming immunotherapy resistance in glioblastoma: challenges and emerging strategies

Glioblastoma (GBM) is the most common and aggressive primary brain tumor in adults, characterized by rapid proliferation, extensive infiltration, and significant intratumoral heterogeneity. Despite advancements in conventional treatments, including surgery, radiotherapy, and chemotherapy, the prognosis for GBM patients remains poor, with a median survival of approximately 15 months. Immunotherapy has emerged as a promising alternative; however, the unique biological and immunological features, including its immunosuppressive tumor microenvironment (TME) and low mutational burden, render it resistant to many immunotherapeutic strategies. This review explores the key challenges in GBM immunotherapy, focusing on immune evasion mechanisms, the blood-brain barrier (BBB), and the TME. Immune checkpoint inhibitors and CAR-T cells have shown promise in preclinical models but have limited clinical success due to antigen heterogeneity, immune cell exhaustion, and impaired trafficking across the BBB. Emerging strategies, including dual-targeting CAR-T cells, engineered immune cells secreting therapeutic molecules, and advanced delivery systems to overcome the BBB, show potential for enhancing treatment efficacy. Addressing these challenges is crucial for improving GBM immunotherapy outcomes.

Therapeutic Targets in Glioblastoma: Molecular Pathways, Emerging Strategies, and Future Directions

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults, characterized by rapid growth, invasive infiltration into surrounding brain tissue, and resistance to conventional therapies. Despite advancements in surgery, radiotherapy, and chemotherapy, median survival remains approximately 15 months, underscoring the urgent need for innovative treatments. Key considerations informing treatment development include oncogenic genetic and epigenetic alterations that may dually serve as therapeutic targets and facilitate treatment resistance. Various immunotherapeutic strategies have been explored and continue to be refined for their anti-tumor potential. Technical aspects of drug delivery and blood-brain barrier (BBB) penetration have been addressed through novel vehicles and techniques including the incorporation of nanotechnology. Molecular profiling has emerged as an important tool to individualize treatment where applicable, and to identify patient populations with the most drug sensitivity. The goal of this review is to describe the spectrum of potential GBM therapeutic targets, and to provide an overview of key trial outcomes. Altogether, the progress of clinical and preclinical work must be critically evaluated in order to develop therapies for GBM with the strongest therapeutic efficacy.

Neurooncology: 2025 update

This collection of studies highlights groundbreaking advancements in brain tumor research, particularly primary CNS tumors and brain metastasis. One major focus is the tumor microenvironment, where alterations in cerebral microcirculation and hypoxic-ischemic conditions have been shown to influence metastatic progression. In glioblastoma, recurrent tumors exhibit distinct DNA methylation profiles, and global DNA methylation has emerged as an independent diagnostic marker for IDH-wildtype glioblastoma. A whole-tumor perspective further emphasizes the extensive intratumoral heterogeneity driving glioblastoma evolution. The immune landscape of glioblastoma is another key area of research. Cranioencephalic functional lymphoid units have been implicated in tumor progression, while time-dependent single-cell phenotyping offers novel insights into immune cell dynamics within glioblastoma. Additionally, histone serotonylation has been identified as a critical epigenetic regulator in ependymoma tumorigenesis. Diagnostic and prognostic innovations are paving the way for improved patient care. Histomorphological features provide enhanced prognosis prediction for glioblastoma patients. Confocal laser microscopy enables real-time intraoperative histopathological diagnostics, and sequencing of cerebrospinal fluid-derived cell-free DNA presents a promising non-invasive diagnostic approach. Together, these top studies of 2024 underscore the complexity of brain tumor biology and the integration of epigenetics, immune interactions, and advanced diagnostics into clinical practice. These insights mark significant progress toward personalized treatment strategies and improved outcomes in neurooncology.

Temporal Apparent Diffusion Coefficient Changes During Chemoradiation: An Imaging Biomarker for Tumor Response Monitoring and Spatial Recurrence Prediction in Glioblastoma

PURPOSE

Apparent diffusion coefficient (ADC) from diffusion-weighted imaging has been shown to detect early treatment response in glioblastoma. This prospective observational serial imaging study aimed to compare ADC changes in gross tumor volume (GTV) regions that developed recurrence versus those that remained recurrence-free.

METHODS AND MATERIALS

Patients with glioblastoma underwent diffusion-weighted imaging at radiation planning (baseline, fraction 0), fraction 10, fraction 20, and 1 month after completing a 6-week course of chemoradiation. Recurrence was contoured at the earliest magnetic resonance imaging showing progression. The intersection of the GTV and recurrence was labeled resistant-GTV, whereas nonintersecting GTV was labeled sensitive-GTV. ADC values and percentage changes from fraction 0 were compared between these regions.

RESULTS

Eighty patients were analyzed. Median absolute ADC values for resistant (0.94 μm2/ms; IQR, 0.84-1.08) and sensitive-GTV (0.93 μm2/ms; IQR, 0.87-1.13) were similar at baseline (P = .193), but statistically significant differences were observed from the start of radiation therapy. Median ADC changes from baseline for resistant- and sensitive-GTV were +2.5% versus +15.1% at fraction 10 (P < .001), +8.1% versus +23.1% at fraction 20 (P < .001), and +21.2% versus +36.4% at 1 month after completing a 6-week course of chemoradiation (P <.001), respectively. Smaller ADC changes at fraction 10 (odds ratio, 0.95; P = .005) and fraction 20 (odds ratio, 0.95; P = .010) were independent predictors of increased risk of GTV failure, adjusting for O6-methylguanine DNA methyltransferase promoter methylation and extent of surgical resection.

CONCLUSIONS

Temporal ADC changes are promising imaging biomarkers for treatment response and spatial recurrence prediction and may provide a target for magnetic resonance imaging-guided biologically adapted radiation clinical trials.

An MRI Radiogenomic Signature to Characterize the Transcriptional Heterogeneity Associated with Prognosis and Biological Functions in Glioblastoma

BACKGROUND

The study sought to establish a radiogenomic signature to evaluate the transcriptional heterogeneity that reflects the prognosis and tumour-related biological functions of patients with glioblastoma.

METHODS

Transcriptional subclones were identified via fully unsupervised deconvolution of RNA sequencing. A genomic prognostic risk score was developed from transcriptional subclone proportions in the development dataset (n = 532) and independently verified in the testing dataset (n = 225). Multimodal magnetic resonance imaging (MRI) analysis involved feature extraction from three distinct anatomical regions across four imaging sequences. Key features were selected to construct a radiogenomic signature predictive of the genomic risk score in the radiogenomic dataset (n = 99), with subsequent survival analysis conducted in the image testing dataset (n = 233).

RESULTS

A total of 8 transcriptional subclones were identified, of which the metabolic pathway subclone and spinocerebellar ataxia subclone were independent risk factors for overall survival. The genomic risk score effectively differentiated patient subgroups with divergent survival outcomes in both development (p < 0.001) and testing datasets (p = 0.0003). Nineteen radiomic features were selected to construct a radiogenomic signature, with these features being linked to hallmark cancer pathways and the malignant behaviours of cancer cells. The radiogenomic signature predicted overall survival in the image testing dataset (hazard ratios (HR) = 1.67, p = 0.011).

CONCLUSIONS

A prognostic radiogenomic signature was established and verified to characterize transcriptional subclones with underlying biological functions in glioblastoma.

Convection-Enhanced Delivery of Auristatin-Conjugated Layer-by-Layer Nanoparticles for Glioblastoma Treatment

Glioblastoma (GBM) has limited treatment options, as the restrictive blood-brain barrier (BBB) prevents most therapeutics from accumulating at sufficient levels in the brain. Convection-enhanced delivery (CED) offers a method for administering therapeutics directly into brain tumor tissue, but free drugs can be cleared rapidly and may be toxic to off-target cells. Drug-loaded nanoparticles (NPs) are a promising platform to prolong the residence time and improve cellular targeting of therapeutics. We designed drug-conjugated NPs comprising a liposomal core modified with a layer-by-layer (LbL) polymer coating to promote tumor penetration, retention, and tumor-selective cellular association. Covalent conjugation of the potent microtubule inhibitor monomethyl auristatin-F (MMAF) to lipid headgroups resulted in striking potency against a range of patient-derived GBM cell lines compared to free MMAF and outperformed an EGFR-targeted antibody-drug conjugate of MMAF under clinical investigation. In vivo, a single CED infusion of LbL-functionalized MMAF NPs in orthotopic GBM-bearing mice displayed improved distribution and retention of both the NPs and the MMAF payload within the tumor. The LbL coating promotes selective uptake by GBM cells and prolongs drug retention, overcoming limitations of rapid clearance associated with traditional CED approaches. This treatment inhibited tumor progression and significantly extended survival compared to free MMAF, MMAF-conjugated liposomes, and an EGFR-MMAF antibody-drug conjugate. This NP platform offers a promising strategy for enhancing local GBM therapy by improving drug exposure within tumors while minimizing systemic toxicity.

Spatial 3D genome organization reveals intratumor heterogeneity in primary glioblastoma samples

Glioblastoma (GBM) is the most prevalent malignant brain tumor with poor prognosis. Although chromatin intratumoral heterogeneity is a characteristic feature of GBM, most current studies are conducted at a single tumor site. To investigate the GBM-specific 3D genome organization and its heterogeneity, we conducted Hi-C experiments in 21 GBM samples from nine patients, along with three normal brain samples. We identified genome subcompartmentalization and chromatin interactions specific to GBM, as well as extensive intertumoral and intratumoral heterogeneity at these levels. We identified copy number variants (CNVs) and structural variations (SVs) and demonstrated how they disrupted 3D genome structures. SVs could not only induce enhancer hijacking but also cause the loss of enhancers to the same gene, both of which contributed to gene dysregulation. Our findings provide insights into the GBM-specific 3D genome organization and the intratumoral heterogeneity of this organization and open avenues for understanding this devastating disease.

Microvascular heterogeneity exploration in core and invasive zones of orthotopic rat glioblastoma via ultrasound localization microscopy

BACKGROUND

We studied the microvascular structure and function of in situ glioblastoma using ultrasound localization microscopy (ULM).

METHODS

The in vivo study was conducted via craniotomy in six Sprague-Dawley rats. Capillary pattern, capillary hemodynamics, and functional quantitative parameters were compared among tumor core, invasive zone, and normal brain tissue with ex vivo micro-computed tomography (micro-CT) and scanning electron microscopy. Correlations between quantitative parameters and histopathological vascular density (VD-H), proliferation index, and histopathological vascular maturity index (VMI-H) were evaluated. Kruskal-Wallis H, ANOVA, Mann-Whitney U, Pearson, and Spearman correlation statistics were used.

RESULTS

Compared to the tumor core, the invasive zone exhibited higher microvascularity structural disorder and complexity, increased hemodynamic heterogeneity, higher local blood flow perfusion (p ≤ 0.033), and slightly lower average flow velocity (p = 0.873). Significant differences were observed between the invasive zone and normal brain tissue across all parameters (p ≤ 0.001). ULM demonstrated higher microstructural resolution compared to micro-CT and a nonsignificant difference compared to scanning electron microscopy. The invasive zone vascular density correlated with VD-H (r = 0.781, p < 0.001). Vessel diameter (r = 0.960, p < 0.001), curvature (r = 0.438, p = 0.047), blood flow velocity (r = 0.487, p = 0.025), and blood flow volume (r = 0.858, p < 0.001) correlated with proliferation index. Vascular density (r = -0.444, p = 0.044) and fractal dimension (r = -0.933, p < 0.001) correlated with VMI-H.

CONCLUSION

ULM provided high-resolution, noninvasive imaging of glioblastoma microvascularity, offering insights into structural/functional abnormalities.

RELEVANCE STATEMENT

ULM technology based on ultrafast ultrasound can accurately quantify the microvessels of glioblastoma, providing a new method for evaluating the effectiveness of antiangiogenic therapy and visualizing disease progression. This method may facilitate early therapeutic assessment.

KEY POINTS

ULM reliably captures the vascular structures and hemodynamic features of glioblastoma in rats. Micro-CT and scanning electron microscopy validated its effectiveness in microvascular non-invasion characterization. ULM is expected to effectively evaluate glioblastoma anti-vascular therapy response.

Tumour-wide RNA splicing aberrations generate actionable public neoantigens

T cell-based immunotherapies hold promise in treating cancer by leveraging the immune system's recognition of cancer-specific antigens1. However, their efficacy is limited in tumours with few somatic mutations and substantial intratumoural heterogeneity2-4. Here we introduce a previously uncharacterized class of tumour-wide public neoantigens originating from RNA splicing aberrations in diverse cancer types. We identified T cell receptor clones capable of recognizing and targeting neoantigens derived from aberrant splicing in GNAS and RPL22. In cases with multi-site biopsies, we detected the tumour-wide expression of the GNAS neojunction in glioma, mesothelioma, prostate cancer and liver cancer. These neoantigens are endogenously generated and presented by tumour cells under physiologic conditions and are sufficient to trigger cancer cell eradication by neoantigen-specific CD8+ T cells. Moreover, our study highlights a role for dysregulated splicing factor expression in specific cancer types, leading to recurrent patterns of neojunction upregulation. These findings establish a molecular basis for T cell-based immunotherapies addressing the challenges of intratumoural heterogeneity.

Molecular principles underlying aggressive cancers

Aggressive tumors pose ultra-challenges to drug resistance. Anti-cancer treatments are often unsuccessful, and single-cell technologies to rein drug resistance mechanisms are still fruitless. The National Cancer Institute defines aggressive cancers at the tissue level, describing them as those that spread rapidly, despite severe treatment. At the molecular, foundational level, the quantitative biophysics discipline defines aggressive cancers as harboring a large number of (overexpressed, or mutated) crucial signaling proteins in major proliferation pathways populating their active conformations, primed for their signal transduction roles. This comprehensive review explores highly aggressive cancers on the foundational and cell signaling levels, focusing on the differences between highly aggressive cancers and the more treatable ones. It showcases aggressive tumors as harboring massive, cancer-promoting, catalysis-primed oncogenic proteins, especially through certain overexpression scenarios, as predisposed aggressive tumor candidates. Our examples narrate strong activation of ERK1/2, and other oncogenic proteins, through malfunctioning chromatin and crosslinked signaling, and how they activate multiple proliferation pathways. They show the increased cancer heterogeneity, plasticity, and drug resistance. Our review formulates the principles underlying cancer aggressiveness on the molecular level, discusses scenarios, and describes drug regimen (single drugs and drug combinations) for PDAC, NSCLC, CRC, HCC, breast and prostate cancers, glioblastoma, neuroblastoma, and leukemia as examples. All show overexpression scenarios of master transcription factors, transcription factors with gene fusions, copy number alterations, dysregulation of the epigenetic codes and epithelial-to-mesenchymal transitions in aggressive tumors, as well as high mutation loads of vital upstream signaling regulators, such as EGFR, c-MET, and K-Ras, befitting these principles.

Spatial biology - unravelling complexity within the glioblastoma microenvironment

The advent and refinement of state-of-the-art spatial biology technologies have facilitated analysis that combines the advantages of high-throughput single cell analysis with techniques that preserve tissue architecture. This combination of cellular phenotyping with retained spatial context provides a much greater understanding of cellular interactions within the tumour microenvironment (TME). For glioblastoma, with its significant intra-tumoural heterogeneity, cellular plasticity, and complex TME, appreciating and understanding these spatial patterns may prove key to improving patient outcomes. This review examines the advances in spatial biology techniques, discusses how these methodologies are being applied to study glioblastoma, and explores how spatial information improves understanding of the TME. Ultimately, it is this spatial context that will accelerate the identification of more effective treatments for glioblastoma.

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.

Single-cell sequencing elucidates the mechanism of NUSAP1 in glioma and its diagnostic and prognostic significance

Background

Personalized precision medicine (PPPM) in cancer immunology and oncology is a rapidly advancing field with significant potential. Gliomas, known for their poor prognosis, rank among the most lethal brain tumors. Despite advancements, there remains a critical need for precise, individualized treatment strategies.

Methods

We conducted a comprehensive analysis of RNA-seq and microarray data from the TCGA and GEO databases, supplemented by single-cell RNA sequencing (scRNA-seq) data from glioma patients. By integrating single-cell sequencing analysis with foundational experiments, we investigated the molecular variations and cellular interactions within neural glioma cell subpopulations during tumor progression.

Results

Our single-cell sequencing analysis revealed distinct gene expression patterns across glioma cell subpopulations. Notably, differentiation trajectory analysis identified NUSAP1 as a key marker for the terminal subpopulation. We found that elevated NUSAP1 expression correlated with poor prognosis, prompting further investigation of its functional role through both cellular and animal studies.

Conclusions

NUSAP1-based risk models hold potential as predictive and therapeutic tools for personalized glioma treatment. In-depth exploration of NUSAP1's mechanisms in glioblastoma could enhance our understanding of its response to immunotherapy, suggesting that targeting NUSAP1 may offer therapeutic benefits for glioma patients.

IDH-mutant astrocytomas with primitive neuronal component have a distinct methylation profile and a higher risk of leptomeningeal spread

IDH-mutant astrocytomas are diffuse gliomas that are defined by characteristic mutations in IDH1 or IDH2 and do not have complete 1p/19q co-deletion. The established grading criteria include histological features of brisk mitotic activity (grade 3) and necrosis and/or microvascular proliferation (grade 4). In addition, homozygous deletion of the CDKN2A/B locus has recently been implemented as a molecular marker for grade 4 IDH-mutant astrocytomas. Here, we describe a subgroup of high-grade IDH-mutant astrocytomas characterised by a primitive neuronal component based on histology and a distinct DNA methylation profile (n = 51, ASTRO PNC). Misinterpretation as carcinoma metastasis was common, since GFAP expression was absent in the primitive neuronal component, whereas TTF-1 expression was detected in 15/19 cases (79%) based on immunohistochemistry. Apart from mutations in IDH1, TP53, and ATRX, we observed enrichment for alterations in RB1 (n = 19/51, 37%) and MYCN (n = 14/51, 27%). Homozygous CDKN2A/B deletion (n = 1/51, 2%) and CDK4 amplification (n = 3/51, 6%) were relatively rare events. Clinical (n = 31 patients) and survival data (n = 23 patients) indicate a clinical behaviour similar to other CNS WHO grade 4 IDH-mutant astrocytomas, however with an increased risk for leptomeningeal (n = 7) and extra-axial (n = 2) spread. Taken together, ASTRO PNC is defined by a distinct molecular and histological appearance that can mimic metastatic disease and typically follows an aggressive clinical course.

Brain-targeting drug delivery systems: The state of the art in treatment of glioblastoma

Glioblastoma (GBM) is the most prevalent primary malignant brain tumor, characterized by a high mortality rate and a poor prognosis. The blood-brain barrier (BBB) and the blood-tumor barrier (BTB) present significant obstacles to the efficacy of tumor-targeted pharmacotherapy, thereby impeding the therapeutic potential of numerous candidate drugs. Targeting delivery of adequate doses of drug across the BBB to treat GBM has become a prominent research area in recent years. This emphasis has driven the exploration and evaluation of diverse technologies for GBM pharmacotherapy, with some already undergoing clinical trials. This review provides a thorough overview of recent advancements and challenges in targeted drug delivery for GBM treatment. It specifically emphasizes systemic drug administration strategies to assess their potential and limitations in GBM treatment. Furthermore, this review highlights promising future research directions in the development of intelligent drug delivery systems aimed at overcoming current challenges and enhancing therapeutic efficacy against GBM. These advancements not only support foundational research on targeted drug delivery systems for GBM but also offer methodological approaches for future clinical applications.

Protein kinase inhibitors as targeted therapy for glioblastoma: a meta-analysis of randomized controlled clinical trials

Glioblastoma (GBM) is the most common and lethal primary brain tumor. The standard treatment for newly diagnosed GBM includes surgical resection, when feasible, followed by radiotherapy and temozolomide-based chemotherapy. Upon disease progression, the anti-vascular endothelial growth factor-A (VEGF-A) monoclonal antibody bevacizumab, can be considered. Given the limited efficacy of pharmacological treatments, particularly for the recurrent disease, several molecularly targeted interventions have been explored, such as small-molecule protein kinase inhibitors (PKIs), inhibiting tyrosine kinase growth factor receptors and downstream signaling pathways involved in GBM angiogenesis and infiltrative behavior. This meta-analysis, based on searches in PubMed and Web Of Science, evaluated 12 randomized controlled trials (RCTs) examining PKIs in patients with newly diagnosed or recurrent GBM. Pooled analysis of shared clinical outcomes - progression-free survival (PFS) and overall survival (OS) - revealed a lack of significant improvements with the use of PKIs. In newly diagnosed GBM, no significant differences were observed in median [-1.02 months, 95 % confidence interval (CI), -2.37-0.32, p = 0.14] and pooled [hazard ratio (HR) = 1.13, 95 % CI, 0.95-1.35, p = 0.17) OS, or in median (0.34 months, 95 % CI, -0.9-1.58, p = 0.60) and pooled (HR = 0.98, 95 % CI, 0.76-1.27, p = 0.89) PFS, when comparing PKI addition to standard chemo-radiotherapy versus chemo-radiotherapy alone. In recurrent GBM, three different analyses were conducted: PKI versus other treatments, PKI combined with other treatments versus those treatments alone, PKI versus PKI combined with other treatments. Also, across these analyses, no significant clinical benefits were found. For instance, when comparing PKI treatment with other treatments, median OS and PFS showed no significant difference (-0.78 months, 95 % CI, -2.12-0.55, p = 0.25; -0.23 months, 95 % CI, -0.79-0.34, p = 0.43, respectively), and similar non-significant results were observed in the pooled analyses (OS: HR = 0.89, 95 % CI, 0.59-1.32, p = 0.55; PFS: HR = 0.83, 95 % CI, 0.63-1.11, p = 0.21). Despite these overall negative findings, some data indicate improved clinical outcomes in a subset of GBM patients treated with certain PKIs (i.e., regorafenib) and encourage further research to identify PKIs with better blood-brain barrier penetration and lower risk for resistance development.

Gemistocytic tumor cells programmed for glial scarring characterize T cell confinement in IDH-mutant astrocytoma

Isocitrate dehydrogenase 1/2 mutant (IDHmt) astrocytoma is considered a T cell-deprived tumor, yet little is known regarding the phenotypes underlying T cell exclusion. Using bulk, single nucleus and spatial RNA and protein profiling, we demonstrate that a distinct spatial organization underlies T cell confinement to the perivascular space (T cell cuff) in IDHmt astrocytoma. T cell cuffs are uniquely characterized by a high abundance of gemistocytic tumor cells (GTC) in the surrounding stroma. Integrative analysis shows that GTC-high tumors are enriched for lymphocytes and tumor associated macrophages (TAM) and express immune cell migration and activation programs. Specifically, GTCs constitute a distinct sub-cluster of the astrocyte-like tumor cell state that co-localizes with immune reactive TAMs. Neighboring GTCs and TAMs express receptor-ligand pairs characteristic of reactive astrogliosis and glial scarring, such as SPP1/CD44 and IL-1β/IL1R1. Collectively, we reveal that T cell confinement in IDHmt astrocytomas associates with GTC-TAM networks that mimic glial scarring mechanisms.

Bridging the gap between tumor and disease: Innovating cancer and glioma models

Recent advances in cancer biology and therapeutics have underscored the importance of preclinical models in understanding and treating cancer. Nevertheless, current models often fail to capture the complexity and patient-specific nature of human tumors, particularly gliomas. This review examines the strengths and weaknesses of such models, highlighting the need for a new generation of models. Emphasizing the critical role of the tumor microenvironment, tumor, and patient heterogeneity, we propose integrating our advanced understanding of glioma biology with innovative bioengineering and AI technologies to create more clinically relevant, patient-specific models. These innovations are essential for improving therapeutic development and patient outcomes.

Cancer neuroscience and glioma: clinical implications

In recent years, it has been increasingly recognized that tumor growth relies not only on support from the surrounding microenvironment but also on the tumors capacity to adapt to - and actively manipulate - its niche. While targeting angiogenesis and modulating the local immune environment have been explored as therapeutic approaches, these strategies have yet to yield effective treatments for brain tumors and remain under refinement. More recently, the nervous system itself has been explored as a critical environmental support for cancer, with extensive neuro-tumoral interactions observed both intracranially and in extracranial sites containing neural components. In the brain, interactions between glioma cells as well as metastatic lesions with neural components have clinical implications for diagnostics, risk assessments, neurological sequelae, and the development of innovative therapeutics. Here, we review these neuro-tumoral dynamics, emphasizing aspects relevant to neurosurgical practice.

Enhancement of the nontumor component in newly diagnosed glioblastoma as a more accurate predictor of local recurrence location: a multicenter study

Background

Although the spatial heterogeneity of glioblastoma (GBM) can be clearly mapped by the habitats generated by magnetic resonance imaging (MRI), the means to accurately predicting the spatial location of local recurrence (SLLR) remains a significant challenge. The aim of this study was to identify the different degrees enhancement of GBM, including the nontumor component and tumor component, and determine their relationship with SLLR.

Methods

A retrospective analysis was performed from three tertiary medical centers, totaling 728 patients with 109 radiation-induced temporal lobe necrosis (TLN) of nasopharyngeal carcinoma (NPC) and 619 with GBM. The spatial location of nontumor component enhancement (SLNTE) and the spatial location of tumor component enhancement (SLTE) for the preoperative images of patients with GBM were identified using TLN as the nontumor component reference by clustering analysis, and then their relationship with the SLLR was analyzed. Decision tree models of 10-fold cross-validation based on SLNTE and SLTE built to predict the SLLR. The area under the curve (AUC) was used to evaluate the predictive efficacy of these models.

Results

The SLNTE had a stronger spatial relationship with SLLR than did SLTE (χ2=4.77; P=0.029). In data set 3, both the SLNTE and SLTE were associated with the SLLR (rSLNTE=0.70, P<0.001; rSLTE=0.34, P=0.005). In data set 4, the SLLR was correlated with SLNTE but not with SLTE (rSLNTE=0.59, P=0.029; rSLTE=0.20, P=0.50). In data sets 3 and 4, the SLNTE-based decision tree models predicted the SLLR with 81% and 79% accuracy, respectively, and the AUC values were greater than 0.80 and 0.75, respectively. Meanwhile, the SLTE-based decision tree models predicted the SLLR with 72% and 50% accuracy, respectively, with AUC values of 0.70 and 0.60, respectively.

Conclusions

Radiation-induced TLN of NPC is a highly effective reference indicator for detecting nontumor components. The tumor periphery adjacent to the nontumor component enhancement of GBM may be associated with a higher risk of local recurrence, which may provide a more accurate imaging basis for performing supertotal resection.

Heterogeneity of intracellular calcium signaling of glioblastoma cells depends on intratumoral location and migration state

Background

Glioblastoma (GB), is an incurable brain tumor characterized by extreme malignancy and invasiveness, and the cellular mechanisms underlying such a severe phenotype are not completely understood. Although calcium (Ca2+) plays an important part in tumor proliferation and infiltration, it remains unclear whether Ca2+ signaling in GB cells is related to its location within the tumor and on the infiltrative potential of the cells.

Methods

In this study, we developed a stably transfected GL261 cell line that coexpresses a red fluorescent protein for actin cytoskeleton staining and the intracellular Ca2+ sensor, GCaMP6s. By means of intravital 2-photon imaging, we have characterized the morphological and functional properties of cells at different locations within the tumor.

Results

Our results showed that cells located at the tumor core are densely packed and rounded in shape, contrasting sharply with the polarized morphology observed in the peripheral cells. This anatomical heterogeneity corresponded to notable variations of the physiological phenotype: cells at the tumor core displayed low Ca2+ activity and very limited motility, while peripheral cells displayed intense Ca2+ activity and increased migration rates. Moreover, peripheral cells formed a cellular ensemble characterized by synchronized Ca2+ activity accompanied by a directionally biased collective motility.

Conclusions

These findings suggest that GB cells manifest activity patterns depending upon their spatial location within the tumor and that these correlate with their migration.

Three-dimensional regulatory hubs support oncogenic programs in glioblastoma

Dysregulation of enhancer-promoter communication in the context of the three-dimensional (3D) nucleus is increasingly recognized as a potential driver of oncogenic programs. Here, we profiled the 3D enhancer-promoter networks of primary patient-derived glioblastoma stem cells (GSCs) in comparison with neuronal stem cells (NSCs) to identify potential central nodes and vulnerabilities in the regulatory logic of this devastating cancer. Specifically, we focused on hyperconnected 3D regulatory hubs and demonstrated that hub-interacting genes exhibit high and coordinated expression at the single-cell level and strong association with oncogenic programs that distinguish IDH-wt glioblastoma patients from low-grade glioma. Epigenetic silencing of a recurrent 3D enhancer hub-with an uncharacterized role in glioblastoma-was sufficient to cause concordant downregulation of multiple hub-connected genes along with significant shifts in transcriptional states and reduced clonogenicity. By integrating published datasets from other cancer types, we also identified both universal and cancer type-specific 3D regulatory hubs which enrich for varying oncogenic programs and nominate specific factors associated with worse outcomes. Genetic alterations, such as focal duplications, could explain only a small fraction of the detected hyperconnected hubs and their increased activity. Overall, our study provides computational and experimental support for the potential central role of 3D regulatory hubs in controlling oncogenic programs and properties.

Glioblastoma functional heterogeneity and enrichment of cancer stem cells with tumor recurrence

Glioblastoma (GBM) is an incurable disease with high intratumoral heterogeneity. Bioinformatic studies have examined transcriptional heterogeneity with differing conclusions. Here, we characterize GBM heterogeneity and highlight critical phenotypic and hierarchical roles for quiescent cancer stem cells (qCSCs). Unsupervised single-cell transcriptomic analysis of patient-derived xenografts (PDXs) delineates six GBM transcriptional states with unique tumor exclusive gene signatures, five of which display congruence with central nervous system (CNS) cell lineages. We employ a surrogate tumor evolution assay by serial xenograft transplantation to demonstrate faithful preservation of somatic mutations, transcriptome, and qCSCs. PDX chemotherapy results in CSC resistance and expansion, also seen in recurrent patient GBM. In aggregate, these novel GBM transcriptional signatures exclusively identify tumor cells and define the hierarchical landscape as stable biologically discernible cell types that allow capture of their evolution upon recurrence, emphasizing the importance of CSCs and demonstrating general relevance to all GBM.

Bioprinting of a multi-composition array to mimic intra-tumor heterogeneity of glioblastoma for drug evaluation

Microextrusion printing is widely used to precisely manufacture microdevices, microphysiological systems, and biological constructs that feature micropatterns and microstructures consisting of various materials. This method is particularly useful for creating biological models that recapitulate in vivo-like cellular microenvironments. Although there is a recent demand for high-throughput data from a single in vitro system, it remains challenging to fabricate multiple models with a small volume of bioinks in a stable and precise manner due to the spreading and evaporation issues of the extruded hydrogel. As printing time increases, the extruded bioink spreads and evaporates, leading to technical problems that decrease printing resolution and stability, as well as biological problems that affect 3D culture space and cell viability. In this study, we describe a novel microextrusion bioprinting technique to stably fabricate a multi-composition array consisting of massive and nanoliter-scale hydrogel dots by using multi-bioink printing and aerosol-based crosslinking techniques to prevent spreading and evaporation issues. We confirmed that the crosslinking aerosol effectively prevented spreading and evaporation by analyzing the morphological changes of the extruded hydrogel. By adjusting the extruding ratio of the bioinks, we were able to print a multi-composition array. This stable and massive array printing technique allowed us to improve the replicates of biological models and provide various data from a single culture system. The array printing technique was applied to recapitulate the intra-tumor heterogeneity of glioblastoma and assess temozolomide efficacy on the array model.

Chromatin accessibility: biological functions, molecular mechanisms and therapeutic application

The dynamic regulation of chromatin accessibility is one of the prominent characteristics of eukaryotic genome. The inaccessible regions are mainly located in heterochromatin, which is multilevel compressed and access restricted. The remaining accessible loci are generally located in the euchromatin, which have less nucleosome occupancy and higher regulatory activity. The opening of chromatin is the most important prerequisite for DNA transcription, replication, and damage repair, which is regulated by genetic, epigenetic, environmental, and other factors, playing a vital role in multiple biological progresses. Currently, based on the susceptibility difference of occupied or free DNA to enzymatic cleavage, solubility, methylation, and transposition, there are many methods to detect chromatin accessibility both in bulk and single-cell level. Through combining with high-throughput sequencing, the genome-wide chromatin accessibility landscape of many tissues and cells types also have been constructed. The chromatin accessibility feature is distinct in different tissues and biological states. Research on the regulation network of chromatin accessibility is crucial for uncovering the secret of various biological processes. In this review, we comprehensively introduced the major functions and mechanisms of chromatin accessibility variation in different physiological and pathological processes, meanwhile, the targeted therapies based on chromatin dynamics regulation are also summarized.

Analysis of DNA Methylation in Gliomas: Assessment of Preanalytical Variables

Precision oncology is driven by biomarkers. For glioblastoma multiforme (GBM), the most common malignant adult primary brain tumor, O6-methylguanine-DNA methyltransferase (MGMT) gene promoter methylation is an important prognostic and treatment clinical biomarker. Time-consuming preanalytical steps such as biospecimen storage, fixation, sampling, and processing are sources of data irreproducibility, and all these preanalytical variables are confounded by intratumor heterogeneity of MGMT promoter methylation. To assess the effect of preanalytical variables on GBM DNA methylation, tissue storage/sampling (CryoGrid), sample preparation multisonicator (PIXUL), and 5-methylcytosine DNA immunoprecipitation (Matrix-MeDIP-qPCR/seq) platforms were used. MGMT promoter methylation status assayed by MeDIP-qPCR was validated with methylation-specific polymerase chain reaction. MGMT promoter methylation levels in frozen and formalin-fixed paraffin-embedded sample pairs were not statistically different, confirming the reliability of formalin-fixed paraffin-embedded for MGMT promoter methylation analysis. Warm ex vivo ischemia (up to 4 hours at 37 °C) and 3 cycles of repeated sample thawing and freezing did not statistically impact 5-methylcytosine at MGMT promoter, exon, and enhancer regions, indicating the resistance of DNA methylation to common variations in sample processing conditions that might be encountered in research and clinical settings. Twenty-six percent to 34% of specimens exhibited intratumor heterogeneity in the MGMT DNA promoter methylation. These data demonstrate that variations in sample fixation, ischemia duration and temperature, and DNA methylation assay technique do not have a statistically significant impact on MGMT promoter methylation assessment. However, intratumor methylation heterogeneity underscores the value of multiple biopsies at different GBM geographic tumor sites in the evaluation of MGMT promoter methylation status. Matrix-MeDIP-seq analysis revealed that MGMT promoter methylation status clustered with other differentially methylated genomic loci (eg, HOXA and lncRNAs) that are resilient to variation in the above preanalytical conditions. These observations offer new opportunities to develop more granular data-based epigenetic GBM biomarkers. In this regard, the high-throughput CryoGrid-PIXUL-Matrix toolbox could be useful.

Functional profiling of murine glioma models highlights targetable immune evasion phenotypes

Cancer-intrinsic immune evasion mechanisms and pleiotropy are a barrier to cancer immunotherapy. This is apparent in certain highly fatal cancers, including high-grade gliomas and glioblastomas (GBM). In this study, we evaluated two murine syngeneic glioma models (GL261 and CT2A) as preclinical models for human GBM using functional genetic screens, single-cell transcriptomics and machine learning approaches. Through CRISPR genome-wide co-culture killing screens with various immune cells (cytotoxic T cells, natural killer cells, and macrophages), we identified three key cancer-intrinsic evasion mechanisms: NFκB signaling, autophagy/endosome machinery, and chromatin remodeling. Additional fitness screens identified dependencies in murine gliomas that partially recapitulated those seen in human GBM (e.g., UFMylation). Our single-cell analyses showed that different glioma models exhibited distinct immune infiltration patterns and recapitulated key immune gene programs observed in human GBM, including hypoxia, interferon, and TNF signaling. Moreover, in vivo orthotopic tumor engraftment was associated with phenotypic shifts and changes in proliferative capacity, with murine tumors recapitulating the intratumoral heterogeneity observed in human GBM, exhibiting propensities for developmental- and mesenchymal-like phenotypes. Notably, we observed common transcription factors and cofactors shared with human GBM, including developmental (Nfia and Tcf4), mesenchymal (Prrx1 and Wwtr1), as well as cycling-associated genes (Bub3, Cenpa, Bard1, Brca1, and Mis18bp1). Perturbation of these genes led to reciprocal phenotypic shifts suggesting intrinsic feedback mechanisms that balance in vivo cellular states. Finally, we used a machine-learning approach to identify two distinct immune evasion gene programs, one of which represents a clinically-relevant phenotype and delineates a subpopulation of stem-like glioma cells that predict response to immune checkpoint inhibition in human patients. This comprehensive characterization helps bridge the gap between murine glioma models and human GBM, providing valuable insights for future therapeutic development.

GBM immunotherapy: Exploring molecular and clinical frontiers

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

High-throughput identification of repurposable neuroactive drugs with potent anti-glioblastoma activity

Glioblastoma, the most aggressive primary brain cancer, has a dismal prognosis, yet systemic treatment is limited to DNA-alkylating chemotherapies. New therapeutic strategies may emerge from exploring neurodevelopmental and neurophysiological vulnerabilities of glioblastoma. To this end, we systematically screened repurposable neuroactive drugs in glioblastoma patient surgery material using a clinically concordant and single-cell resolved platform. Profiling more than 2,500 ex vivo drug responses across 27 patients and 132 drugs identified class-diverse neuroactive drugs with potent anti-glioblastoma efficacy that were validated across model systems. Interpretable molecular machine learning of drug-target networks revealed neuroactive convergence on AP-1/BTG-driven glioblastoma suppression, enabling expanded in silico screening of more than 1 million compounds with high patient validation accuracy. Deep multimodal profiling confirmed Ca2+-driven AP-1/BTG-pathway induction as a neuro-oncological glioblastoma vulnerability, epitomized by the anti-depressant vortioxetine synergizing with current standard-of-care chemotherapies in vivo. These findings establish an actionable framework for glioblastoma treatment rooted in its neural etiology.

Supercontinuum-tailoring multicolor imaging reveals spatiotemporal dynamics of heterogeneous tumor evolution

Tumor heterogeneity and tumor evolution contribute to cancer treatment failure. To understand how selective pressures drive heterogeneous tumor evolution, it would be useful to image multiple important components and tumor subclones in vivo. We propose a supercontinuum-tailoring two-photon microscope (SCT-TPM) and realize simultaneous observation of nine fluorophores with a single light beam, breaking through the 'color barrier' of intravital two-photon fluorescence imaging. It achieves excitation multiplexing only by modulating the phase of fiber supercontinuum (SC), allowing to capture rapid events of multiple targets with maintaining precise spatial alignment. We employ SCT-TPM to visualize the spatiotemporal dynamics of heterogeneous tumor evolution under host immune surveillance, particularly the behaviors and interactions of six tumor subclones, immune cells and vascular network, and thus infer the trajectories of tumor progression and clonal competition. SCT-TPM opens up the possibility of tumor lineage tracking and mechanism exploration in living biological systems.

The Three Pillars of Glioblastoma: A Systematic Review and Novel Analysis of Multi-Omics and Clinical Data

Glioblastoma is the most fatal and common malignant brain tumor, excluding metastasis and with a median survival of approximately one year. While solid tumors benefit from newly approved drugs, immunotherapy, and prevention, none of these scenarios are opening for glioblastoma. The key to unlocking the peculiar features of glioblastoma is observing its molecular and anatomical features tightly entangled with the host's central nervous system (CNS). In June 2024, we searched the PUBMED electronic database. Data collection and analysis were conducted independently by two reviewers. Results: A total of 215 articles were identified, and 192 were excluded based on inclusion and exclusion criteria. The remaining 23 were used for collecting divergent molecular pathways and anatomical features of glioblastoma. The analysis of the selected papers revealed a multifaced tumor with extreme variability and cellular reprogramming that are observable within the same patient. All the variability of glioblastoma could be clustered into three pillars to dissect the physiology of the tumor: 1. necrotic core; 2. vascular proliferation; 3. CNS infiltration. These three pillars support glioblastoma survival, with a pivotal role of the neurovascular unit, as supported by the most recent paper published by experts in the field.

SUMOylation modification of HNRNPK at the K422 site promotes invasion in glioblastoma

Glioblastoma multiforme (GBM) is a highly heterogeneous brain tumor with limited treatment options. Recent studies revealed cellular heterogeneity and the potential for interconversion between distinct cell types on the basis of RNA sequencing and single-cell analyses. The ability of different cell types to adapt to their surrounding environment and undergo transformation significantly complicates the study and treatment of GBM. In this study, we reveal that HNRNPK-SUMO1 expression is predominantly found in the GBM infiltration area. SUMOylation of the K422 residue of HNRNPK interferes with its DNA binding ability, thereby disrupting downstream transcription, and ultimately leading to transitions between different states of glioblastoma stem cells. Although the proneural subtype is considered to have a better prognosis, transitioning towards this state promotes tumor invasion. These findings serve as a reminder to exercise caution when considering treatments targeting specific cellular subtypes.