Sporadic hemangioblastomas (sHBs) are less prevalent than those in von Hippel-Lindau (VHL) disease. Surgical resection and radiation therapy remain the standard treatments, and medical treatment options for sHBs are limited. While belzutifan shows a favorable response in VHL-associated HBs, its efficacy in sHBs is uncertain. We present a case of probable belzutifan-induced tumor reduction in a patient with sHB. We present a case of a 65-year-old man with progressive right-sided hemifacial paresthesia, retro-orbital pain, and periorbital edema, subsequently diagnosed with progressive right trigeminal nerve-associated sHB. The patient did not meet clinical or genetic criteria for VHL disease. Serial magnetic resonance imaging (MRI) demonstrated significant tumor progression over seven years. Treatment included 12.5 Gy of radiation in 2016, subtotal resection in 2021, and re-radiation with 50.6 Gy in 2022. Repeat debulking resection was deemed high-risk due to tumor location, and prior treatment precluded further re-radiation. Following multidisciplinary review and patient preference, medical therapy was pursued, and belzutifan at 120 mg/day was initiated. MRI demonstrated tumor reduction from 3.4 cm to 3.1 cm by month 2. Due to anemia and fatigue, belzutifan was reduced and continued at 80 mg/day with stable hemoglobin above 10.0 and tolerable fatigue. Serial brain MRIs showed a durable tumor reduction, with a −7.00 mm/year median linear growth rate reduction by month 13. To our knowledge, this is the first report of belzutifan treatment for sHB, resulting in tumor reduction. Belzutifan may offer a possible treatment option for residual, progressive, and/or pre-surgical sHBs.

Glioblastoma (GBM) is a devastating disease, with standard-of-care therapies still yielding dismal survival outcomes. GBM cells are protected by the blood-brain and blood-tumor barriers, which severely limit therapeutic agent delivery from the bloodstream. Focused ultrasound (FUS), in combination with microbubbles (MBs), addresses this challenge by enhancing drug delivery. However, dilated and tortuous brain tumor vasculature disrupts MB flux and oscillation, which may limit FUS-mediated delivery. Here, we evaluated whether normalizing tumor vasculature via chronic neoadjuvant VEGFR2 inhibition (aVEGFR2, DC101) improves subsequent FUS-mediated small molecule drug delivery. After aVEGFR2 administration had pre-normalized GL261 glioma vasculature through reduced permeability and vascular caliber, T1 mapping MRI of FUS-delivered Multihance (MH) contrast agent, a model small molecule drug, yielded no change in total delivery. However, radiomic analysis of the T1 maps indicated that FUS-mediated model drug penetration into otherwise poorly accessible tumor regions was improved with aVEGFR2 pre-treatment. This improvement was accompanied by acoustic signatures suggestive of more stable MB oscillation. These results were then compared to those achieved with acute aVEGF pre-treatment, a regimen that copied the permeability reduction of chronic aVEGFR2 without reducing vascular caliber. This comparison identified reduced vascular caliber as the probable mechanism of improved delivery uniformity, perhaps acting through a shift in MB oscillation towards more stable regimes. Our results indicate that neoadjuvant aVEGFR2 cooperates with FUS-mediated small molecule drug delivery through a unique biophysical mechanism. This mechanism may be leveraged to further augment the efficacy of combination therapies against GBM that entail blocking VEGF signaling.

This study investigates the synergistic therapeutic potential of a novel combination of the repurposed drug simvastatin with irinotecan chemotherapy towards glioblastoma (GBM) and the underlying molecular mechanisms. In vitro efficacy of simvastatin and irinotecan alone and in combination against diverse GBM lines (U251MG, G34, SB28) was assessed using mechanistically distinct cell viability assays. RNA-Sequencing was performed to uncover the top pathways and genes affected by these drugs, followed by validation of promising pathways (TGF-β signaling and cell death) using targeted phosphoproteomics and in vitro genetic manipulation and functional assays. We observed robust in vitro synergy at nanomolar concentrations between simvastatin and irinotecan across diverse GBM lines. Notably, irinotecan alone and in combination with simvastatin reduced mRNA expression of TGF-β family members. Targeted phosphoproteomics and functional experiments further showed significant inhibition of TGF-β signaling with both treatment types. Additionally, a role for apoptosis and enrichment of caspase-independent cell death pathways (autophagy, ferroptosis) as well as immunological (interferons, complement, inflammatory responses, TNF-α) and oncogenic (K-RAS/ERK) signaling pathways were observed with the combination treatment. Besides the first detailed demonstration of a robust synergy between simvastatin and irinotecan against GBM lines, this study shows for the first time that both irinotecan and the combination treatment converge on inhibition of TGF-β signaling. This is notable given the lack of TGF-β inhibitors in the clinic. Collectively, this study provides preclinical data suggesting this novel drug combination be tested in patients with GBM and TGF-β driven cancers.

Cellular invasion is a primary challenge to complete resection and treatment of glioblastoma, the most aggressive and deadly primary brain tumor. The brain tumor microenvironment actively stimulates glioma invasion through a multitude of cellular, chemical, and biophysical cues. We and others have shown elevated interstitial fluid flow at the tumor border is one such biophysical cue that directly stimulates invasion through tumor-intrinsic signaling and, in other tumor types, priming of cancer-associated stromal cells. It is currently unclear if interstitial flow similarly primes neuroglial cells to promote glioma cell dissemination and can be targeted for therapeutic purposes. Here, we show elevated interstitial flow upregulates expression of sphingosine-1-phosphate receptor 3 (S1PR3) in glial astrocytes and microglia, which drives glioma cell invasion via chemotaxis. Flow-induced expression of glial S1PR3 is tumor-independent and displays a biphasic relationship to fluid shear stress magnitude in vitro and flow rate in vivo . Inhibition of glial S1PR3 in a tissue engineered culture model and orthotopic mouse model abrogates flow-stimulated invasion, demonstrating a tumor-extrinsic approach to limiting glioblastoma progression. Given prior evidence of a pro-inflammatory role for glial S1PR3, identification of S1PR3 as a disease-agnostic marker of flow-stimulated glia may also have therapeutic implications across myriad neuropathologies.

Background:Glioblastoma (GBM) is an aggressive brain cancer with limited treatment options and high recurrence rates. The blood-brain barrier (BBB) impedes therapeutic delivery for the brain, limiting systemic treatment efficacy. Focused ultrasound (FUS) combined with microbubbles (MBs) can transiently open the BBB (BBBO), enhancing drug delivery and modulating the tumor immune microenvironment (TME). However, the disorganized and leaky vasculature in GBM limits the effectiveness of FUS-mediated BBBO. Vascular normalization using antiangiogenic therapy may enhance both immune modulation and delivery. This study aimed to investigate whether vascular normalization via VEGFR-2 blockade with DC101, alone or in combination with FUS+MBs, improves TME remodeling in a murine GBM model. Methods:CT2A glioma-bearing mice were treated with DC101, a VEGFR2 inhibitor, either alone or in combination with FUS+MBs. Tumor growth, survival, vessel permeability, immune cell profiling, and adhesion molecule expression were evaluated using immunohistochemistry, flow cytometry, and confocal microscopy. Results:DC101 monotherapy significantly reduced tumor growth and prolonged survival. It reduced tumor vessel permeability and increased ICAM1 expression on CD31+ endothelial cells, consistent with vascular normalization. DC101 also reduced FOXP3+ regulatory T cells (Tregs) and increased the CD8/Treg ratio, indicating a more immunostimulatory TME. However, the addition of FUS+MBs in this normalized vascular environment did not further alter the immune landscape, suggesting a stable, quiescent TME. Conclusion:DC101-mediated vascular normalization beneficially remodels the GBM TME and creates a quiescent platform for supporting future FUS-based therapeutic delivery. This combinatorial strategy offers a promising approach to overcoming BBB-related barriers in glioma treatment.

Effective salvage therapy for atypical and anaplastic meningiomas has not been established. Phase I/II clinical trial evidence for using cyclin-dependent kinase (CDK) inhibitors to treat meningiomas, in particular abemaciclib, has been documented. We aim to report a case to demonstrate the possible utility of a multitargeted treatment approach in aggressive meningiomas. We present a 38-year-old woman with progressive multifocal Grade 2 atypical meningiomas expressing clinical and radiologic response to a multi-drug regimen centered on abemaciclib based on genetic profiling. Mechanistically, combining abemaciclib with drugs that antagonize potential resistance mechanisms induced by CDK inhibitors, may synergistically promote cytotoxic effects in meningiomas. This case highlights the combination of abemaciclib with chloroquine and disulfiram/copper as a prospective novel salvage therapy for recurrent atypical meningiomas.

Stereoselective recognition is a powerful means to differentiate selective versus non-specific activity of small molecules in complex biological systems. Here, we disclose stereochemically defined, sulfonyltriazole inhibitors of the lipid enzyme diacylglycerol kinase-alpha (DGKα), a key metabolic checkpoint for T cell effector function. Acute treatment with the covalent DGKα inhibitor AHL-7160 recruited endogenous DGKα to the plasma membrane in a stereoselective and isozyme-specific manner. The membrane translocation activity of AHL-7160 correlated with blockade of cellular phosphatidic acid production and potentiation of primary T cell-mediated killing of a glioblastoma cell line. Quantitative chemoproteomics revealed Y669 and K411 as sites of AHL-7160 modification on endogenous DGKα in cells. Extended treatments resulted in proteasome-dependent and proteome-wide selective degradation of DGKα in T cells. Collectively, these findings establish covalent DGKα ligands as potent molecular glues with translational potential in immunotherapy.

Glioblastoma recurrence is a major hindrance to treatment success and is driven by the invasion of glioma stem cells (GSCs) into healthy tissue that are inaccessible to surgical resection and are resistant to existing chemotherapies. Tissue-level fluid movement, or interstitial fluid flow (IFF), regulates GSC invasion in a manner dependent on the tumor microenvironment (TME), highlighting the need for model systems that incorporate both IFF and the TME. We present an accessible method for replicating the invasive TME in glioblastoma: a hyaluronan-collagen I hydrogel composed of human GSCs, astrocytes, and microglia seeded in a tissue culture insert. Elevated IFF can be represented by applying a fluid pressure head to the hydrogel. Additionally, this model can be tuned to replicate inter- or intra-patient differences in cellular ratios, flow rates, or matrix stiffnesses. Invasion can be quantified, while gels can be harvested for a variety of outcomes, including GSC invasion, flow cytometry, protein or RNA extraction, or imaging.

In glioblastoma, a mesenchymal phenotype is associated with especially poor patient outcomes. Various glioblastoma microenvironmental factors and therapeutic interventions are purported drivers of the mesenchymal transition, but the degree to which these cues promote the same mesenchymal transitions and the uniformity of those transitions, as defined by molecular subtyping systems, is unknown. Here, we investigate this question by analyzing publicly available patient data, surveying commonly measured transcripts for mesenchymal transitions in glioma-initiating cells (GIC), and performing next-generation RNA sequencing of GICs. Analysis of patient tumor data reveals that TGFβ, TNFα, and hypoxia signaling correlate with the mesenchymal subtype more than the proneural subtype. In cultured GICs, the microenvironment-relevant growth factors TGFβ and TNFα and the chemotherapeutic temozolomide promote expression of commonly measured mesenchymal transcripts. However, next-generation RNA sequencing reveals that growth factors and temozolomide broadly promote expression of both mesenchymal and proneural transcripts, in some cases with equal frequency. These results suggest that glioblastoma mesenchymal transitions do not occur as distinctly as in epithelial-derived cancers, at least as determined using common subtyping ontologies and measuring response to growth factors or chemotherapeutics. Further understanding of these issues may identify improved methods for pharmacologically targeting the mesenchymal phenotype in glioblastoma.

Glioblastoma (GBM) is a common and devastating primary brain tumor, with median survival of 16–18 months after diagnosis in the setting of substantial resistance to standard-of-care and inevitable tumor recurrence. Recent work has implicated the brain microenvironment as being critical for GBM proliferation, invasion, and resistance to treatment. GBM does not operate in isolation, with neurons, astrocytes, and multiple immune populations being implicated in GBM tumor progression and invasiveness. The goal of this review article is to provide an overview of the available in vitro, ex vivo, and in vivo experimental models for assessing GBM-brain interactions, as well as discuss each model’s relative strengths and limitations. Current in vitro models discussed will include 2D and 3D co-culture platforms with various cells of the brain microenvironment, as well as spheroids, whole organoids, and models of fluid dynamics, such as interstitial flow. An overview of in vitro and ex vivo organotypic GBM brain slices is also provided. Finally, we conclude with a discussion of the various in vivo rodent models of GBM, including xenografts, syngeneic grafts, and genetically-engineered models of GBM.

The laminar flow profiles in microfluidic systems coupled to rapid diffusion at flow streamlines have been widely utilized to create well-controlled chemical gradients in cell cultures for spatially directing cell migration. However, within hydrogel-based closed microfluidic systems of limited depth (<= 0.1 mm), the biomechanical cues for the cell culture are dominated by cell interactions with channel surfaces rather than with the hydrogel microenvironment. Also, leaching of poly(dimethylsiloxane) (PDMS) constituents in closed systems and the adsorption of small molecules to PDMS alter chemotactic profiles. To address these limitations, we present the patterning and integration of a PDMS-free open fluidic system, wherein the cell-laden hydrogel directly adjoins longitudinal channels that are designed to create chemotactic gradients across the 3D culture width, while maintaining uniformity across its similar to 1 mm depth to enhance cell-biomaterial interactions. This hydrogel-based open fluidic system is assessed for its ability to direct migration of U87 glioma cells using a hybrid hydrogel that includes hyaluronic acid (HA) to mimic the brain tumor microenvironment and gelatin methacrylate (GelMA) to offer the adhesion motifs for promoting cell migration. Chemotactic gradients to induce cell migration across the hydrogel width are assessed using the chemokine CXCL12, and its inhibition by AMD3100 is validated. This open-top hydrogel-based fluidic system to deliver chemoattractant cues over square-centimeter-scale areas and millimeter-scale depths can potentially serve as a robust screening platform to assess emerging glioma models and chemotherapeutic agents to eradicate them.

This file contains supplementary figures, primer sequences for PCR, and supplementary references

PDF file - 247K, Transfection efficiency of U87 cells infected with lentiviruses encoding anti-miR-148, mCherry, and hygromycin resistance gene.

Supplemental Tables 1-3. Supplementary Table 1: Correlations in the vandetanib/RT/TMZ arm between best radiographic responses with pre-treatment and on-treatment changes in blood biomarkers. Supplementary Table 2: Correlations in the vandetanib/RT/TMZ arm between overall survival with pre-treatment and on-treatment changes in blood biomarkers. Supplementary Table 3: Comparison of PFS or OS by log-rank p-value based on tissue biomarker analysis

PDF file - 23K, miR-148a inhibits MIG6 and BIM mRNA expression.

PDF file - 25K, MIG6 mediates the effects of miR-148a on cell proliferation.

Radiation therapy (RT) provides therapeutic benefits for patients with glioblastoma (GBM), but inevitably in-duces poorly understood global changes in GBM and its microenvironment (TME) that promote radio -resistance and recurrence. Through a cell surface marker screen, we identified that CD142 (tissue factor or F3) is robustly induced in the senescence-associated b-galactosidase (SA-bGal)-positive GBM cells after irradiation. F3 promotes clonal expansion of irradiated SA-bGal+ GBM cells and orchestrates oncogenic TME remodeling by activating both tumor-autonomous signaling and extrinsic coagulation pathways. Intratumoral F3 signaling induces a mesenchymal-like cell state transition and elevated chemokine secretion. Simultaneously, F3 -mediated focal hypercoagulation states lead to activation of tumor-associated macrophages (TAMs) and extracellular matrix (ECM) remodeling. A newly developed F3-targeting agent potently inhibits the aforementioned oncogenic events and impedes tumor relapse in vivo. These findings support F3 as a critical regulator for therapeutic resistance and oncogenic senescence in GBM, opening potential therapeutic avenues.

Supplemental Figure: Mean plasma concentrations of vandetanib.