Quiñones‐Hinojosa, Alfredo

Abstract Extracellular matrix (ECM) stiffening correlates with tumor invasion in various cancer types, including glioblastoma (GBM). Increased matrix stiffness promotes a migratory phenotype through dysregulation of cell-ECM bidirectional communication. Exposure to stiffer environments is sensed by cells, which then adapt in ways that promote invasive behavior. These adaptive changes are imprinted onto the cells and persist even after they are placed in new, softer microenvironments via a process known as “mechanical memory.” Mechanical memory is believed to be driven by mechanosensitive transcription factor activity and epigenetic remodeling. Glioblastoma recurrence is linked to the ability of cells to disperse and infiltrate the surrounding healthy tissue. Extracellular matrix stiffness in GBM is heterogeneous; it starts with a softer tumor core and becomes progressively stiffer toward the tumor’s edges, potentially promoting sustained tumor invasion through mechanical memory. This review discusses the role of ECM stiffness in cancer cell behavior and the implications of ECM stiffening in GBM. We then describe the findings associated with mechanical memory and relay underlying mechanisms currently understood to drive the preservation of mechanically primed phenotypes. Finally, we discuss how matrix stiffness can drive migratory phenotypes in GBM cells and the potential role that progressive ECM dysregulation at the tumor periphery can link the formation of invasive tumor niches to the aggressive, resistant, and mesenchymal-like phenotypes present in GBM recurrent tumors.

Study Design Systematic Review. Objective To assess the current literature regarding the accuracy of different imaging modalities and criteria used to assess lumbar fusion, and their correlation with surgical direct observation as the current Gold Standard. Methods Following PRISMA guidelines, we conducted a comprehensive search of PubMed, Embase, Google Scholar, and Cochrane Library, studies were included if they focused on patients with a prior history of lumbar interbody fusion and at least 1 year of radiographic follow-up. The review assessed the sensitivity, specificity, and accuracy of different imaging techniques, and their correlation with surgical findings. Results Thirteen studies (1989-2019) were reviewed, including 715 patients, common imaging modalities included plain radiographs (53.8%), Computed Tomography (CT) (69.2%), and dynamic radiographs (30.7%). CT appeared as the most utilized modality post-2006. There was substantial variability in diagnostic accuracy, with CT showing high variability in sensitivity and specificity. Descriptive criteria for fusion were widely used, but interobserver agreement was generally low. Conclusion The review highlights a lack of standardized criteria for assessing lumbar fusion. Despite advancements in imaging techniques, the variability in diagnostic parameters suggests a need for consensus and multicentric studies to stablish reliable, universal criteria for evaluating fusion success.

Abstract Glioblastoma (GBM), the most aggressive primary brain tumor in adults, presents significant challenges due to its universal recurrence and limited survival rates, exacerbated when proximal to the lateral ventricles (LV). The subpopulation of brain tumor-initiating cells (BTICs) plays a pivotal role in tumor initiation and invasiveness, interacting with the microenvironment, particularly the cellular components in the subventricular zone (SVZ). Some mechanisms of intercellular communication present in the SVZ include paracrine, autocrine, direct cell contact, gap junctions, nanotubes, and more recently extracellular vesicles (EVs). EVs are membrane-bound particles released by cells that are central to intercellular communication. They have the ability to carry bioactive proteins, RNA, and other molecules that influence recipient cell behavior.This study investigates the role of EVs in GBM's communication with non-cancer cells. Our findings indicate that BTIC-derived EVs promote migration and proliferation (*p < 0.02, ****p <0.001) in neural progenitor cells (NPCs) in vitro, highlighting the EVs' role in altering the microenvironment. To identify the protein cargo contained in GBM-derived EVs, we utilized the innovative proximity-labeling system TurboID. We successfully induced TurboID expression in primary-cultured human BTICs from GBM patients, enabling the unbiased biotinylation of proteins in EVs. We isolated biotinylated proteins from BTIC lysates and BTIC-EVs, preserving the integrity of EVs, and conducted proteomic analysis via mass spectrometry. Our method marks the first implementation of TurboID for unbiased global labeling of EV protein cargo in primary GBM cells. This approach facilitates the investigation of EV-mediated communication and potential therapeutic targets, contributing to the understanding of GBM's complex interactions with the brain's microenvironment and the identification of biomarkers for improved diagnosis and treatment response. Citation Format: Marissa Russo, Emily Norton-Ramos, Maria Jose Ulloa Navas, Alfredo Quinones-Hinojosa, Hugo Guerrero-Cazares. Elucidating glioblastoma-derived extracellular vesicle cargo using TurboID: Implications for tumor microenvironment adaptation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6579.

Immunosuppression within the tumor microenvironment (TME) poses a significant challenge to the efficacy of Chimeric Antigen Receptor (CAR) T-cell therapy in solid tumors, including glioblastoma (GBM), the most common and deadly primary brain tumor. Tumor and TME-residing immunosuppressive cells can hijack program death 1(PD1) pathway to evade antitumor T-cell immunity by upregulating its ligand, PD-L1. Thus, targeting PD-L1 emerges as a promising therapeutic strategy to simultaneously eliminate tumor cells and immunosuppressive components within the TME. We developed a novel PD-L1-targeting CAR T-cell therapy, MC9999, and investigated its therapeutic effects against GBM. The antigen-specific cytotoxicity of MC9999 CAR T-cells was firmly validated using a LN229 GBM cell line and its PD-L1-deficient variant, as well as patient-derived brain tumor-initiating cells (BTICs). Furthermore, in vivo therapeutic antitumor effects were confirmed in orthotopic GBM models through intracranial administration of MC9999 CAR T-cells. To pave the way to the translation of MC9999 CAR T-cell therapy to patient bedside, we established a unique experimental system using patient-specific CAR T-cells against their own tumor and immunosuppressive cells. High-quality, patient-specific MC9999 CAR T-cells were manufactured using T cells isolated from peripheral blood, while paired autologous BTICs were generated to serve as target cells. Autologous immunosuppressive cells include monocyte-derived M2 macrophages from patient’s peripheral blood and tumor-associated macrophages (TAMs) isolated from patient’s tumor. Data from multiple patients’ samples consistently demonstrated that these patient-specific MC9999 CAR T-cells elicited robust cytotoxicity against autologous GBM tumor and TME-residing immunosuppressive cells, supporting our hypothesis that targeting PD-L1 effectively address both tumor and its TME. Immunohistochemistry (IHC) staining of our GBM patients’ tissues showed that PD-L1 expression was restricted to tumor cells and macrophages /microglia within the tumor, with no expression detected in neurons, astrocytes, oligodendrocytes, or blood vessels. These findings suggest that MC9999 CAR T-cells can be safely delivered to the brain without compromising normal cell populations. Ongoing studies are underway to further validate the safety profile of MC9999 CAR T-cell therapy. Collectively, the data obtained from this preclinical study support the effectiveness, feasibility and safety of local administration of MC9999 CAR T-cells as a promising new approach for GBM treatment. These encouraging results have motivated us to prepare an Investigational New Drug application to initiate a phase I clinical trial. Citation Format: Yan Luo, Yaqing Qie, Maria J. Ulloa-Navas, Jesus E. Sanchez-Garavito, Vanessa K. Jones, Martha E. Gadd, Mieu M. Brooks, Tanya Hundal, Andrew D. Brim, Isas K. Vazquez-Rosario, Haidong Dong, Alfredo Quinones-Hinojosa, Hong Qin. Intracranial delivery of MC9999 CAR T-cell therapy: a novel strategy to simultaneously eliminate GBM tumors and immunosuppressive components in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4812.

OBJECTIVE Unmet global neurosurgical needs pose a significant challenge, as do unequal opportunities for neurosurgical education and training across the globe. Mission:BRAIN is a nonprofit organization working to provide neurosurgical expertise and resources to both patients and healthcare providers in underserved areas. It operates globally, with local chapters involving primarily medical students. Its presence in Europe has expanded in the last few years with initiatives that contribute to shaping an international approach to global neurosurgery challenges. The authors aim to investigate the impact of student-led organizations, such as Mission:BRAIN, on global neurosurgery, with a focus on low-income countries and low- to middle-income countries, while also assessing the changes observed within the European group during its initial 2 years. METHODS Quantitative and qualitative analyses were employed to investigate changes in the number of chapters, members, and events. The perceived impact was evaluated using a Likert scale survey administered to European members. RESULTS Between 2022 and 2023, the number of European chapters increased by 150% (n = 10) and memberships doubled. Of the 102 survey respondents, 56.9% were female and 42.2% were male. Similarly, the number of events grew by 240%, with a significant increase in educational events (325%, p = 0.007). Participation in events increased by 10.13%, reflecting growing interest and engagement. For most members (72.6%), the activities in the European region have increased global awareness of the importance of neurosurgical care in underserved areas; for 45.1% of them, outreach events have effectively communicated the importance of neurosurgical care to nonmedical audiences. For 67.6% of the members, European chapters have contributed to fostering collaboration and knowledge sharing among medical students and healthcare providers. Furthermore, 59% agreed that Mission:BRAIN initiatives have contributed to addressing disparities in neurosurgical care and education. CONCLUSIONS Mission:BRAIN’s growth in Europe showcases the pivotal role of medical students. The impact of the organization’s activities demonstrates the students’ potential to contribute to the overarching effort of bridging worldwide gaps in healthcare and education and calls for their active participation and recognition.

Abstract Purpose: Monitoring disease progression in patients with high-grade gliomas (HGG) is challenging due to treatment-related changes in imaging and the requirement for neurosurgical intervention to obtain diagnostic tissue. DNA junctions in HGG often amplify oncogenes, making these DNA fragments potentially more abundant in blood than monoallelic mutations. In this study, we piloted a cell-free DNA approach for disease detection in the plasma of patients with HGG by leveraging patient-specific DNA junctions associated with oncogene amplifications. Experimental Design: Whole-genome sequencing of grade 3 or 4 isocitrate dehydrogenase–mutant or wild-type astrocytomas was utilized to identify amplified junctions. Individualized qPCR assays were developed using patient-specific primers designed for the amplified junction. ctDNA levels containing these junctions were measured in patient plasma samples. Results: Unique amplified junctions were evaluated by individualized semi-qPCR assays in presurgical plasma of 18 patients, 15 with tumor-associated focal amplifications and three without tumor-associated focal amplifications. high copy-number junctions were robustly detected in the plasma of 14 of 15 (93.3%) patients with amplified junctions and none of the controls. Changes in junction abundance correlated with disease trajectory in serial plasma samples from five patients, including increased abundance of amplified junctions preceding radiographic disease progression. Conclusions: In patients with grade 3 or 4 astrocytomas who had tumor-associated amplifications, patient-specific amplified junctions were successfully detected in assayed plasma from most patients. Longitudinal analysis of plasma samples correlated with disease trajectory, including cytoreduction and progression.

BACKGROUND AND OBJECTIVES: Despite standard of care with maximal safe resection and chemoradiation, glioblastoma (GBM) is the most common and aggressive type of primary brain cancer. Surgical resection provides a window of opportunity to locally treat gliomas while the patient is recovering and before initiating concomitant chemoradiation. The objective was to assess the safety and establish the maximum tolerated dose of adipose-derived mesenchymal stem cells (AMSCs) for the treatment of recurrent GBM. Secondary objectives were to assess the toxicity profile and long-term survival outcomes of patients enrolled in the trial. In addition, biospecimens will be collected to explore the local and systemic responses to this therapy. METHODS: We will conduct a phase 1, dose-escalated, nonrandomized, open-label, clinical trial of patients with GBM who are undergoing surgical resection for recurrence. Up to 18 patients will receive intracavitary application of AMSCs encapsulated in fibrin glue during surgical resection. All patients will be followed for up to 5 years for safety and survival data. Adverse events will be recorded using the CTCAE V5.0. EXPECTED OUTCOMES: This study will explore the maximum tolerated dose of AMSCs along with the toxicity profile of this therapy in patients with recurrent GBM. In addition, preliminary long-term survival and progression-free survival outcome analysis will be used to power further randomized studies. Finally, cerebrospinal fluid and blood will be obtained throughout the treatment period to investigate circulating molecular and inflammatory tumoral/stem cell markers and explore the mechanism of action of the therapeutic intervention. DISCUSSION: This prospective translational study will determine the initial safety and toxicity profile of local delivery of AMSCs for recurrent GBM. It will also provide additional survival metrics for future randomized trials.