Hypoxia-driven protease legumain promotes immunosuppression in glioblastoma.

Glioblastoma (GBM) is a hypoxic and "immune-cold" tumor containing rich stromal signaling molecules and cell populations, such as proteases and immunosuppressive tumor-associated macrophages (TAMs). Here, we seek to profile and characterize the potential proteases that may contribute to GBM immunosuppression. Legumain (LGMN) emerges as the key protease that is highly enriched in TAMs and transcriptionally upregulated by hypoxia-inducible factor 1-alpha (HIF1α).

Repurposing Clemastine to Target Glioblastoma Cell Stemness.

Brain tumor-initiating cells (BTICs) and tumor cell plasticity promote glioblastoma (GBM) progression. Here, we demonstrate that clemastine, an over-the-counter drug for treating hay fever and allergy symptoms, effectively attenuated the stemness and suppressed the propagation of primary BTIC cultures bearing amplification. These effects on BTICs were accompanied by altered gene expression profiling indicative of their more differentiated states, resonating with the activity of clemastine in promoting the differentiation of normal oligodendrocyte progenitor cells (OPCs) into mature oligodendrocytes.

Kunitz-type protease inhibitor TFPI2 remodels stemness and immunosuppressive tumor microenvironment in glioblastoma.

Glioblastoma (GBM) tumors consist of multiple cell populations, including self-renewing glioblastoma stem cells (GSCs) and immunosuppressive microglia. Here we identified Kunitz-type protease inhibitor TFPI2 as a critical factor connecting these cell populations and their associated GBM hallmarks of stemness and immunosuppression. TFPI2 promotes GSC self-renewal and tumor growth via activation of the c-Jun N-terminal kinase-signal transducer and activator of transcription (STAT)3 pathway.

CDK7 and CDK9 inhibition interferes with transcription, translation, and stemness, and induces cytotoxicity in GBM irrespective of temozolomide sensitivity.

Background: Glioblastoma (GBM) is refractory to current treatment modalities while side effects of treatments result in neurotoxicity and cognitive impairment. Here we test the hypothesis that inhibiting CDK7 or CDK9 would effectively combat GBM with reduced neurotoxicity.

Methods: We examined the effect of a CDK7 inhibitor, THZ1, and multiple CDK9 inhibitors (SNS032, AZD4573, NVP2, and JSH150) on GBM cell lines, patient-derived temozolomide (TMZ)-resistant and responsive primary tumor cells and glioma stem cells (GSCs).

Spatially resolved transcriptomic profiles reveal unique defining molecular features of infiltrative 5ALA-metabolizing cells associated with glioblastoma recurrence.

Background: Spatiotemporal heterogeneity originating from genomic and transcriptional variation was found to contribute to subtype switching in isocitrate dehydrogenase-1 wild-type glioblastoma (GBM) prior to and upon recurrence. Fluorescence-guided neurosurgical resection utilizing 5-aminolevulinic acid (5ALA) enables intraoperative visualization of infiltrative tumors outside the magnetic resonance imaging contrast-enhanced regions. The cell population and functional status of tumor responsible for enhancing 5ALA-metabolism to fluorescence-active PpIX remain elusive.

Isolation and profiling of viable tumor cells from human ex vivo glioblastoma cultures through single-cell transcriptomics.

Single-cell RNA-sequencing (scRNA-seq) is becoming a ubiquitous method in profiling the cellular transcriptomes of both malignant and non-malignant cells from the human brain. Here, we present a protocol to isolate viable tumor cells from human ex vivo glioblastoma cultures for single-cell transcriptomic analysis. We describe steps including surgical tissue collection, sectioning, culturing, primary tumor cells inoculation, growth tracking, fluorescence-based cell sorting, and population-enriched scRNA-seq.

Sialic acid metabolism orchestrates transcellular connectivity and signaling in glioblastoma.

Background: In glioblastoma (GBM), the effects of altered glycocalyx are largely unexplored. The terminal moiety of cell coating glycans, sialic acid, is of paramount importance for cell-cell contacts. However, sialic acid turnover in gliomas and its impact on tumor networks remain unknown.

Technical report: surgical preparation of human brain tissue for clinical and basic research.

Background: The study of the distinct structure and function of the human central nervous system, both in healthy and diseased states, is becoming increasingly significant in the field of neuroscience. Typically, cortical and subcortical tissue is discarded during surgeries for tumors and epilepsy. Yet, there is a strong encouragement to utilize this tissue for clinical and basic research in humans.

Postoperative risk of IDH-mutant glioma-associated seizures and their potential management with IDH-mutant inhibitors.

Seizures are a frequent complication of adult-type diffuse gliomas, and are often difficult to control with medications. Gliomas with mutations in isocitrate dehydrogenase 1 or 2 (IDHmut) are more likely than IDH-wild type (IDHwt) gliomas to cause seizures as part of their initial clinical presentation. However, whether IDHmut is also associated with seizures during the remaining disease course, and whether IDHmut inhibitors can reduce seizure risk, are unclear.

Generation of B-cell-based cellular vaccine for cancer in murine models.

A B-cell-based cellular vaccine (B), produced from 4-1BBL B cells, can select tumor-specific B cells that, upon ex vivo culture, can generate tumor-specific antibodies and activate T cells. Here, we present a protocol to generate a B-cell-based vaccine in a CT2A orthotopic glioma murine model. We describe steps for B production involving glioma cell implantation, tissue harvesting, 4-1BBL B cell isolation, and activation.

Oncogenic long noncoding RNA LINC02283 enhances PDGF receptor A-mediated signaling and drives glioblastoma tumorigenesis.

Background: Long noncoding RNAs (lncRNAs) regulate the etiology of complex diseases and cancers, including glioblastoma (GBM). However, lncRNA-based therapies are limited because the mechanisms of action of many lncRNAs with their binding partners are not completely understood.

Methods: We used transcriptomic and genomic data to analyze correlations between LINC02283 and PDGFRA (platelet-derived growth factor receptor A).

STING agonist-loaded, CD47/PD-L1-targeting nanoparticles potentiate antitumor immunity and radiotherapy for glioblastoma.

As a key component of the standard of care for glioblastoma, radiotherapy induces several immune resistance mechanisms, such as upregulation of CD47 and PD-L1. Here, leveraging these radiotherapy-elicited processes, we generate a bridging-lipid nanoparticle (B-LNP) that engages tumor-associated myeloid cells (TAMCs) to glioblastoma cells via anti-CD47/PD-L1 dual ligation. We show that the engager B-LNPs block CD47 and PD-L1 and promote TAMC phagocytic activity.

Glioblastoma-instructed microglia transition to heterogeneous phenotypic states with phagocytic and dendritic cell-like features in patient tumors and patient-derived orthotopic xenografts.

Background: A major contributing factor to glioblastoma (GBM) development and progression is its ability to evade the immune system by creating an immune-suppressive environment, where GBM-associated myeloid cells, including resident microglia and peripheral monocyte-derived macrophages, play critical pro-tumoral roles. However, it is unclear whether recruited myeloid cells are phenotypically and functionally identical in GBM patients and whether this heterogeneity is recapitulated in patient-derived orthotopic xenografts (PDOXs). A thorough understanding of the GBM ecosystem and its recapitulation in preclinical models is currently missing, leading to inaccurate results and failures of clinical trials.

Radiosensitization of IDH-Mutated Gliomas through ZMYND8 - a Pathway to Improved Outcomes.

Isocitrate dehydrogenase 1-mutant (IDH1m) gliomas are recalcitrant tumors for which radiotherapy remains a standard treatment. A recent study identified ZMYND8 as a key mediator of radioresistance for IDH1m gliomas, and pharmacologic targeting of this pathway may heighten radiotherapy-induced tumor response, providing a prospect of improved clinical outcomes. See related article by Carney et al.

Intranasal delivery of nanoliposomal SN-38 for treatment of diffuse midline glioma.

Objective: Diffuse midline gliomas, including diffuse intrinsic pontine gliomas (DIPGs), are among the most malignant and devastating childhood brain cancers. Despite aggressive treatment, nearly all children with these tumors succumb to their disease within 2 years of diagnosis. Due to the anatomical location of the tumors within the pons, surgery is not a treatment option, and distribution of most systematically administered drugs is limited by the blood-brain barrier (BBB).

Challenging Cases in Neuro-Oncology.

Neuro-oncology encompasses a broad field focusing on an array of neoplasms, many of which can mimic several diseases. Neurologists will often be involved in the initial diagnostic evaluation and management of these patients. Their insight is central to optimizing the diagnostic yield and providing high-level clinical care.

Determining venous thromboembolism risk in patients with adult-type diffuse glioma.

Venous thromboembolism (VTE) is a life-threating condition that is common in patients with adult-type diffuse gliomas, yet thromboprophylaxis is controversial because of possible intracerebral hemorrhage. Effective VTE prediction models exist for other cancers, but not glioma. Our objective was to develop a VTE prediction tool to improve glioma patient care, incorporating clinical, blood-based, histologic, and molecular markers.

Neuro-oncology at the American Society for Clinical Oncology 2022 Annual Meeting.

In the following brief report, we highlight the advances in the neuro-oncology space from the ASCO 2022 Annual Meeting. We put into context the phase 2 and 3 trials and how these may alter the standard of care going forward. In addition, we highlight some other earlier work that will lead to future and potentially practice-changing trials.

A multi-institutional phase II trial of bevacizumab for recurrent and refractory meningioma.

Background: Systemic therapies for refractory meningiomas are limited with no FDA-approved therapeutics. Vascular endothelial growth factor (VEGF) is a signaling protein associated with neovascularization, peritumoral edema, and meningioma tumorigenesis.

Methods: This phase II study investigates the efficacy of bevacizumab (BEV), a VEGF binding monoclonal antibody, in patients with progressive Grade I (G1M), Grade II (G2M), Grade III (G3M) meningioma, and other non-parenchymal tumors including vestibular schwannoma ( = 4) and hemangiopericytoma ( = 4) with the primary endpoint of progression-free survival rate at 6-months (PFS-6).

ELK3 modulates the antitumor efficacy of natural killer cells against triple negative breast cancer by regulating mitochondrial dynamics.

Background: Triple negative breast cancer (TNBC) is the most lethal subtype of breast cancer due to its aggressive behavior and frequent development of resistance to chemotherapy. Although natural killer (NK) cell-based immunotherapy is a promising strategy for overcoming barriers to cancer treatment, the therapeutic efficacy of NK cells against TNBC is below expectations. E26 transformation-specific transcription factor ELK3 (ELK3) is highly expressed in TNBCs and functions as a master regulator of the epithelial-mesenchymal transition.

DNA damage and metabolic mechanisms of cancer drug resistance.

Cancer drug resistance is one of the main barriers to overcome to ensure durable treatment responses. While many pivotal advances have been made in first combination therapies, then targeted therapies, and now broadening out to immunomodulatory drugs or metabolic targeting compounds, drug resistance is still ultimately universally fatal. In this brief review, we will discuss different strategies that have been used to fight drug resistance from synthetic lethality to tumor microenvironment modulation, focusing on the DNA damage response and tumor metabolism both within tumor cells and their surrounding microenvironment.

Unconventional Protein Secretion in Brain Tumors Biology: Enlightening the Mechanisms for Tumor Survival and Progression.

Non-canonical secretion pathways, collectively known as unconventional protein secretion (UPS), are alternative secretory mechanisms usually associated with stress-inducing conditions. UPS allows proteins that lack a signal peptide to be secreted, avoiding the conventional endoplasmic reticulum-Golgi complex secretory pathway. Molecules that generally rely on the canonical pathway to be secreted may also use the Golgi bypass, one of the unconventional routes, to reach the extracellular space.