Glioblastoma Multiforme Tumors Research Articles

3D-Printed Tumor-on-a-Chip Model for Investigating the Effect of Matrix Stiffness on Glioblastoma Tumor Invasion.

Glioblastoma multiform (GBM) tumor progression has been recognized to be correlated with extracellular matrix (ECM) stiffness. Dynamic variation of tumor ECM is primarily regulated by a family of enzymes which induce remodeling and degradation. In this paper, we investigated the effect of matrix stiffness on the invasion pattern of human glioblastoma tumoroids. A 3D-printed tumor-on-a-chip platform was utilized to culture human glioblastoma tumoroids with the capability of evaluating the effect of stiffness on tumor progression. To induce variations in the stiffness of the collagen matrix, different concentrations of collagenase were added, thereby creating an inhomogeneous collagen concentration. To better understand the mechanisms involved in GBM invasion, an in silico hybrid mathematical model was used to predict the evolution of a tumor in an inhomogeneous environment, providing the ability to study multiple dynamic interacting variables. The model consists of a continuum reaction-diffusion model for the growth of tumoroids and a discrete model to capture the migration of single cells into the surrounding tissue. Results revealed that tumoroids exhibit two distinct patterns of invasion in response to the concentration of collagenase, namely ring-type and finger-type patterns. Moreover, higher concentrations of collagenase resulted in greater invasion lengths, confirming the strong dependency of tumor behavior on the stiffness of the surrounding matrix. The agreement between the experimental results and the model's predictions demonstrates the advantages of this approach in investigating the impact of various extracellular matrix characteristics on tumor growth and invasion.

Unravelling the Glioblastoma Tumour Microenvironment: Can Aptamer Targeted Delivery Become Successful in Treating Brain Cancers?

The key challenges to treating glioblastoma multiforme (GBM) are the heterogeneous and complex nature of the GBM tumour microenvironment (TME) and difficulty of drug delivery across the blood-brain barrier (BBB). The TME is composed of various neuronal and immune cells, as well as non-cellular components, including metabolic products, cellular interactions, and chemical compositions, all of which play a critical role in GBM development and therapeutic resistance. In this review, we aim to unravel the complexity of the GBM TME, evaluate current therapeutics targeting this microenvironment, and lastly identify potential targets and therapeutic delivery vehicles for the treatment of GBM. Specifically, we explore the potential of aptamer-targeted delivery as a successful approach to treating brain cancers. Aptamers have emerged as promising therapeutic drug delivery vehicles with the potential to cross the BBB and deliver payloads to GBM and brain metastases. By targeting specific ligands within the TME, aptamers could potentially improve treatment outcomes and overcome the challenges associated with larger therapies such as antibodies.

Neuroblastoma and Glioblastoma Cases With Amplified Oncogenes Have Reduced Numbers of Tumor-Resident Adaptive Immune Receptor Recombinations.

In certain cancers, oncogene amplification is correlated with an immunologically cold or noninflamed, tumor immune microenvironment (TIME) and a worse prognosis, for example, in the case of MYCN-amplified neuroblastoma (NBL). However, for other cancer types, the relationship between oncogene amplification and immune response is more complicated or unresolved. One such cancer is glioblastoma multiforme (GBM), in which the epidermal growth factor receptor (EGFR) oncogene is commonly amplified. Unlike MYCN-amplified NBL, EGFR-amplified GBM has not been shown to correlate with a distinct survival probability. Given this contrasting state for NBL and GBM, we sought to apply a genomics approach to evaluating the immune response for cases with gene amplification. Our results confirmed and added further specificity to the cold TIME of MYCN-amplified NBL. Moreover, we demonstrated a novel state of immunologically cold EGFR-amplified GBM tumors. This approach to using copy number variation and immune receptor recombination read recovery levels to assess gene amplification and TIME, respectively, may be particularly efficient for the rapid evaluation of many other cancer types.

SYST-31 PROBIOTIC DELIVERY TO ORTHOTOPIC GLIOBLASTOMA MULTIFORME MODELS AS AN IMMUNOTHERAPY

Abstract Therapeutic bacteria have been shown to be effective as an immunotherapy in several types of solid tumors because of their inherent immunogenicity and ability to target tumor tissue with systemic administration. Furthermore, advances in synthetic biology enable production and release of cancer therapeutics from bacteria. However, there is little work describing therapeutic probiotics in brain cancers such as glioblastoma multiforme (GBM). To bridge this gap, we tested different routes of administration for delivery of engineered strains of E. coli Nissle (EcN), and observed the colonization of orthotopic GBM tumors in immunocompetent mouse models. In these models, we successfully colonized tumors using both intratumoral and intravenous injection with little to no observable off-target colonization. This specificity in both delivery methods demonstrates that systemic delivery of wild-type EcN is sufficient to achieve targeted colonization of the tumor. After systemic delivery of bacteria was established in GBM, we sought to reduce edema reactions to the bacteria that occurred after colonization. To reduce the inflammatory response, we treated the edema with antibodies against vascular endothelial growth factor (VEGF), which are a clinical standard treatment for high intracranial pressure. Injecting anti-VEGF antibodies prior to bacteria administration substantially increased the survival rate compared to the mice not given anti-VEGF, suggesting that anti-VEGF significantly reduces the toxicity resulting from the bacteria that has been observed in our work and that of other works. This work therefore opens up the possibility of further work in optimizing the engineered strains for treating GBM.

Effect of folic acid-linked chitosan-coated PLGA-based curcumin nanoparticles on the redox system of glioblastoma cancer cells.

Oxidative stress is one of the carcinogenic mechanisms underlying the development of glioblastoma multiforme (GBM), a highly aggressive brain tumor type associated with poor prognosis. Curcumin is known to be an efficient antioxidant, anti-inflammatory, and anticancer compound. However, its poor solubility in water, inappropriate pharmacokinetics, and low bioavailability limit its use as an antitumor drug. We prepared PLGA-based curcumin nanoparticles changed with folic acid and chitosan (curcumin-PLGA-CS-FA) and evaluated its effects on GBM tumor cells' redox status. The nanoprecipitation method was used to synthesize CU nanoparticles (CU-NPs). The size, morphology, and stability were characterized by DLS, SEM, and zeta potential analysis, respectively. The CU-NPs' toxic properties were studied by MTT assay and measuring the intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) concentrations. The study was completed by measuring the gene expression levels and activity of superoxide dismutase, catalase, glutaredoxin, and thioredoxin antioxidant enzymes. The size, polydispersity index, and zeta potential of CU-NPs were 77.27 nm, 0.29, and -22.45 mV, respectively. The encapsulation efficiency was approximately 98%. Intracellular ROS and MDA levels decreased after CU-NP treatment. Meanwhile, the CU-NPs increased gene expression and activity of superoxide dismutase, catalase, glutaredoxin, and thioredoxin antioxidant enzymes. CU-NPs might be effective in the prevention and treatment of glioblastoma cancer by modulating the antioxidant-oxidant balance.

Neurosurgical Treatment of Brain Tumors: An Analysis of Current Strategies

We have extensively studied the strategies available to many patients admitted to the Neurosurgery Department of the Khyber Teaching Hospital, Peshawar to combat malignant brain diseases. Our survey focused on interviewing leading neurosurgeons, learning about their procedures, and carefully reviewing numerous previous case studies. During our study, a total of sixty cases were observed. We found that craniotomy was the most prevalent method for removing brain tumours, followed by endoscopic surgery and that some patients were sent to specialized clinics for stereotactic and radio surgical procedures. The findings revealed a correlation between tumour type and tumour site, with glioblastoma multiforme and metastatic brain tumours having the greatest rates of morbidity and mortality after surgery. According to the results, craniotomy is the go-to neurosurgical operation for removing brain tumours, and the kind of brain tumour is a crucial determinant in determining the risk of postoperative complications and mortality. The results of this study may have far-reaching consequences for the development of neurosurgical knowledge and technique.

The application of cannabidiol in the treatment of glioblastoma

Glioblastoma multiforme (GBM), a high-grade astrocytoma, is an incurable brain tumor associated with genetic heterogeneity and dysregulated signaling pathways. As alternations of the endocannabinoid system have been demonstrated in GBM cells, the substances affecting its key elements may potentially inhibit tumor progression. Preclinical models indicate that CBD inhibits GBM tumor growth by inhibiting cellular proliferation, migration, and invasion but also promotes autophagy and apoptosis of tumor cells. Moreover, clinical trials indicate the safety and positive results regarding the survival of GBM patients upon cannabinoids treatment. Nevertheless, more human clinical trials with large sample sizes are urgently needed to implement cannabinoids, including CBD, into standard GBM treatment.

Influence of physical and radiobiological models on evaluation of radiotherapy treatment fractionation schedules for GBM brain tumours

This study aims to evaluate the radiotherapy planning performance considering the clinical results of glioblastoma multiforme (GBM)-treated patients from both physical and radiobiological perspectives. Radiotherapy plans are done for 20 patients with GBM tumors who have received radical VMAT treatment on Eclipse-13.5. Dosimetric and radiobiological evaluation metrics are estimated to compare the two plans in terms of TCP, NTCP, and P+ in the context of the evaluated physical metrics. Both conventional and hypofractionation give better dose homogeneity and conformity to the tumour. In addition, hypofractionation schedule coverage targets cells with radiation doses higher than conventional schemes. However, both schedules are at acceptable and safe levels. Statistically, the calculated metrics showed good significance between conventional and hypofractionated radiotherapy schedules. The results have led to the safe use of hypofractionated radiotherapy that can be extended for different tumours, which helps in breaking down the waiting list of patients in many hospitals, especially in cases of pandemics such as COVID-19.

Role of extent of resection on the survival of glioblastoma multiforme

Background. Glioblastoma Multiforme (GBM) is the most prevalent form of brain cancer. The effect of Extent of Resection (EOR) on GBM survival is controversial. EOR degree, pre- and postoperative tumour volume estimation, and significance to residual tumour volume are still challenged. GBM has a 14-month Overall Survival (OS) rate. There is no evidence of a link between EOR and OS survival. We wish to determine whether GBM tumour removal increases survival. Methods. At the Regional Center for Neurosurgery and Neurology in Uzhhorod, Ukraine, we conducted a retrospective evaluation of 86 consecutive patients diagnosed with glioblastoma who underwent surgery between January 1, 2010, and December 31, 2020, and who are being followed until January 1, 2022. Patients were selected if they met the following criteria: they were at least 18 years old, they had a diagnosis of glioblastoma (primary, secondary, or recurrent), they were either IDH mutants or wild types, they had an MRI within 2 weeks before surgery, and they had another MRI within 72 hours after surgery. Before and after surgery, we did a volumetric analysis of gadolinium-enhanced T1 MRI scans of the tumour to figure out EOR. Partial resection (PR) is <70%, sub-total resection (STR) is 70-90%, near-total resection (NTR) is 91-99%, and gross total resection (GTR) is >99%. By comparing pre- and post-operative volumes with the EOR, the Kaplan-Meier survival curve and Cox's regression analysis determined the impact of the EOR on survival rates. Many researchers considered a p value of 0.05 or below to be significant. Results. A total of 86 patients were included in the analysis after being subjected to the criteria used to narrow the pool of potential participants. The average length of time people lived was 15 months. For PR patients, the median survival time was 3 months, for STR patients it was 10 months, and for NTR patients it was 16 months. Patients receiving GTR, on the other hand, had a considerably better outcome, with a median survival time of 36 months. This data demonstrate a direct correlation between EOR and survival rates. It was discovered that EOR improvement affected post-op survival. High EOR patients have a better prognosis for survival. Adjuvant therapy, pre- and post-operative KPS score, pre- and post-operative tumour volume, and gender also contributed significantly to enhanced survival. Conclusion. Patients with glioblastoma appear to benefit from a more aggressive treatment strategy that combines maximal safe resection with the use of salvage adjuvant therapy. There was a correlation between complete resection (gross total resection) of intracranial GBM and improved survival. Whenever feasible, complete surgical removal of the tumour is recommended.

Intra-lesion injection of activated Natural Killer (NK) cells in recurrent malignant brain tumors

Despite multi-modal therapies for patients with malignant brain tumors, their median survival is < 2 years. Recently, NK cells have provided cancer immune surveillance through their direct natural cytotoxicity and by modulating dendritic cells to enhance the presentation of tumor antigens and regulate T-cell-mediated antitumor responses. However, the success of this treatment modality in brain tumors is unclear. The main reasons are; the brain tumor microenvironment, the NK cell preparations and administration, and the donor selection. Our previous study showed that intracranial injection of activated haploidentical NK cells resulted in the eradication of glioblastoma tumor mass in the animal model without any evidence of tumor recurrence. Therefore, in the present study, we evaluated the safety of intra-surgical cavity or intra cerebrospinal fluid (CSF) Injectionofex vivoactivated haploidentical NK cells in six patients with recurrent glioblastoma multiform (GBM) and malignant brain tumors resistance to chemo/radiotherapy. Our results indicated that activated haploidentical NK cells express activator and inhibitor markers and can kill the tumor cells. However, their cytotoxic potential on patient-derived GBM (PD-GBM) was more than that of its cell line. Also, their infusion increased the overall disease control rate by about 33.3%, with a mean survival of 400 days. Moreover, we showed that local administration of the activated haploidentical NK cells in malignant brain tumors is safe, feasible, tolerated at higher doses, and cost-effective.

Study of Gene Expression in Glioblastoma Hypoxic Model

Inspite of multi model cure therapy the mortality rate among the patients of brain tumor always remain high.The low survival rate is due to the ability of these tumors to recur quickly and aggressively. The cellular, genetic, and epigenetic heterogeneity of Glioblastoma multiforme tumors makes designing targeted treatments difficult. Within the tumor there are distinct subpopulations of cells that are stem-like in their behavior and are critical as therapeutic target. The regulation of these cells at molecular level is not yet properly studied. The presence of hypoxic environment controls the stem cells and slower down the progression of tumor. The goal of this work is to use PCR to determine gene expression in glial cells that have been exposed to hypoxia.

NADPH Oxidase Subunit CYBB Confers Chemotherapy and Ferroptosis Resistance in Mesenchymal Glioblastoma via Nrf2/SOD2 Modulation.

Glioblastoma multiforme (GBM) is a highly heterogeneous disease with a mesenchymal subtype tending to exhibit more aggressive and multitherapy-resistant features. Glioblastoma stem-cells derived from mesenchymal cells are reliant on iron supply, accumulated with high reactive oxygen species (ROS), and susceptible to ferroptosis. Temozolomide (TMZ) treatment is the mainstay drug for GBM despite the rapid development of resistance in mesenchymal GBM. The main interconnection between mesenchymal features, TMZ resistance, and ferroptosis are poorly understood. Herein, we demonstrated that a subunit of NADPH oxidase, CYBB, orchestrated mesenchymal shift and promoted TMZ resistance by modulating the anti-ferroptosis circuitry Nrf2/SOD2 axis. Public transcriptomic data re-analysis found that CYBB and SOD2 were highly upregulated in the mesenchymal subtype of GBM. Accordingly, our GBM cohort confirmed a high expression of CYBB in the GBM tumor and was associated with mesenchymal features and poor clinical outcome. An in vitro study demonstrated that TMZ-resistant GBM cells displayed mesenchymal and stemness features while remaining resilient to erastin-mediated ferroptosis by activating the CYBB/Nrf2/SOD2 axis. The CYBB maintained a high ROS state to sustain the mesenchymal phenotype, TMZ resistance, and reduced erastin sensitivity. Mechanistically, CYBB interacted with Nrf2 and consequently regulated SOD2 transcription. Compensatory antioxidant SOD2 essentially protected against the deleterious effect of high ROS while attenuating ferroptosis in TMZ-resistant cells. An animal study highlighted the protective role of SOD2 to mitigate erastin-triggered ferroptosis and tolerate oxidative stress burden in mice harboring TMZ-resistant GBM cell xenografts. Therefore, CYBB captured ferroptosis resilience in mesenchymal GBM. The downstream compensatory activity of CYBB via the Nrf2/SOD2 axis is exploitable through erastin-induced ferroptosis to overcome TMZ resistance.

Distinct Cholesterol Localization in Glioblastoma Multiforme Revealed by Mass Spectrometry Imaging.

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor in adults and is highly resistant to chemo- and radiotherapies. GBM has been associated with alterations in lipid contents, but lipid metabolism reprogramming in tumor cells is not fully elucidated. One of the key hurdles is to localize the lipid species that are correlated with tumor growth and invasion. A better understanding of the localization of abnormal lipid metabolism and its vulnerabilities may open up to novel therapeutic approaches. Here, we use time-of-flight secondary ion mass spectrometry (ToF-SIMS) to spatially probe the lipid composition in a GBM biopsy from two regions with different histopathologies: one region with most cells of uniform size and shape, the homogeneous part, and the other with cells showing a great variation in size and shape, the heterogeneous part. Our results reveal elevated levels of cholesterol, diacylglycerols, and some phosphatidylethanolamine in the homogeneous part, while the heterogeneous part was dominated by a variety of fatty acids, phosphatidylcholine, and phosphatidylinositol species. We also observed a high expression of cholesterol in the homogeneous tumor region to be associated with large cells but not with macrophages. Our findings suggest that ToF-SIMS can distinguish in lipid distribution between parts within a human GBM tumor, which can be linked to different molecular mechanisms.

Nucleic acid immunotherapeutics and vaccines: A promising approach to glioblastoma multiforme treatment

Glioblastoma multiforme (GBM) is a deadly and difficult to treat primary brain tumor for which satisfactory therapeutics have yet to be discovered. While cancer immunotherapeutics, such as immune checkpoint inhibitors, have successfully improved the treatment of some other types of cancer, the poorly immunogenic GBM tumor cells and the immunosuppressive GBM tumor microenvironment have made it difficult to develop GBM immunotherapeutics. Nucleic acids therapeutics and vaccines, particularly those of mRNA, have become a popular field of research in recent years. This review presents the progress of nucleic acid therapeutics and vaccines for GBM and briefly covers some representative delivery methods of nucleic acids to the central nervous system (CNS) for GBM therapy.

Abstract 443: Therapeutic targeting of GPR68 activated by acidic extracellular microenvironment induces ferroptosis in glioblastoma cells

Abstract The Warburg Effect is a common feature of cancer cells characterized by increased glucose uptake and fermentation of glucose to lactate even in the presence of oxygen. While it is commonly accepted that Warburg Effect promotes the growth, survival, proliferation, and long-term maintenance of cancers, its precise function and its downstream mediators remain unclear. A key physiological consequence of the Warburg effect is lactate secretion, which acidifies the tumor milieu, thought to promote oncogenesis and confer tumor resistance to chemotherapy and radiotherapy. Glioblastoma multiforme (GBM) is one of the most aggressive and deadly cancers, characterized by cellular heterogeneity and plasticity, which are thought to drive extreme therapeutic resistance. Despite their heterogeneity, common hallmarks of GBM tumors are high levels of aerobic glycolysis (“Warburg Effect”) and a resultant acidic tumor microenvironment (TME), which promotes tumor progression. In an in vivo zebrafish developmental screen, we identified ogremorphin (OGM), a small molecule inhibitor of GPR68/OGR-1, a G-protein coupled receptor (GPCR) which is activated by extracellular protons. Using ogremorphin and pHluorin2-GPI, a novel sensor of extracellular acidification, we demonstrate that glioblastoma cells acidify their own environment in vitro and activate GPR68, and visualize, for the first time, the establishment of the acidic extracellular microenvironment during the formation of GBM spheroids in vitro. Selective inhibition of GPR68 causes robust cell death in all 12 glioblastoma cell lines tested to date, despite genetic and molecular heterogeneity, without toxicity on healthy cells in whole animals. Mechanistically, GPR68 inhibition activates ferroptosis, a programmed cell death characterized by lipid peroxidation, in an ATF4 (activating transcription factor 4)-dependent manner. Finally, in GBM cells, ogremorphin treatment demonstrates strong synergistic effects with the frontline therapeutics temozolomide and ionizing radiation. Our results indicate that GPR68 activation by extracellular acidification is a key cancer survival pathway downstream of the Warburg Effect, and that GPR68 inhibition, either alone or in combination with temozolomide and radiation therapy, is a promising therapeutic approach to selectively induce ferroptosis in GBM tumors. Citation Format: Charles H. Williams, Leif R. Neitzel, Jessica Cornell, Samantha Rea, Ian Mills, Maya Silver-Isenstadt, Jovanni D. Ahmad, Henry Brem, Betty Tyler, Eli E. Bar, Charles C. Hong. Therapeutic targeting of GPR68 activated by acidic extracellular microenvironment induces ferroptosis in glioblastoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 443.

Abstract 5114: Development of personalized RNA-based immunotherapeutics for glioblastom

Abstract Background: The development of successful immunotherapy targeting antigens in glioblastoma multiforme (GBM) remains a challenge owing to antigen heterogeneity and the low mutation burden in GBM. Cancer immunogenomics represents a complementary approach to the application of genomics in developing novel immunotherapies for GBM. Our goal is to develop a personalized RNA-based therapeutic vaccine that simultaneously targets a selected pool of tumor rejection antigens including all neoantigens and tumor-associated antigens (TAAs) as identified using cancer immunogenomics. We evaluated the treatment efficacy of these RNA therapeutics in combination with adoptive cellular therapy and checkpoint inhibitors. Methods: We identified immunogenic neoantigens and TAAs that are aberrantly overexpressed in KR158-luc and GL261 murine GBM tumors using our cancer immunogenomics pipeline called the Open Reading Frame Antigen Network (O.R.A.N.). A tumor antigen-specific RNA library was created for each tumor using a novel gene enrichment strategy and validated by RNAseq. Tumor-bearing animals were treated with adoptively transferred ex vivo expanded lymphocytes and dendritic cells loaded with the tumor antigen-specific RNA as vaccines. Additionally, we treated animals with the tumor antigen-specific RNA vaccines in combination with anti-PD-1 checkpoint-blockade therapy. Tumor progression and survival outcomes were analyzed to evaluate the treatment efficacies. We determined the peripheral and tumor-infiltrating lymphocyte responses using flow cytometry, TCR sequencing, and single cell RNAseq. Results: The tumor antigen-specific RNA vaccines were significantly effective in slowing the progression of murine GBM tumors in combination with both the adoptive cellular therapy and the checkpoint blockade therapy and improved the outcome of these therapies as compared to monotherapy alone. Additionally, we identified antigen-specific T cells targeting several of our predicted antigens and an increase in tumor-infiltrating lymphocytes and memory T cells in the treated animals. Conclusion: Here, we developed an RNA-based immunotherapy that simultaneously targets numerous tumor-specific antigens and demonstrated its therapeutic efficacy in preclinical models of GBM. Citation Format: Vrunda Trivedi, Changlin Yang, Oleg Yegorov, Kelena Klippel, Graeme Fenton, Christina von Roemeling, Lan Hoang-Minh, Elizabeth Ogando-Rivas, Paul Castillo, Kyle Dyson, Ginger Moore, Duane Mitchell. Development of personalized RNA-based immunotherapeutics for glioblastom. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5114.

Abstract 691: Irradiated whole tumor cells pulsed with mannan-BAM, TLR ligands and anti-CD40 antibody serve as a potent tumor cell vaccine against glioblastoma

Abstract Despite numerous therapeutic advances in cancers, the treatment of glioblastoma multiforme (GBM) remains a challenge. Boosting T-lymphocyte mediated responses against GBM offers a promising approach towards solving this problem. Herein, we present a therapeutic vaccination strategy that promotes the phagocytosis of tumor cells, enhances tumor antigen presentation, and induces a tumor-specific adaptive immune response with subsequent tumor eradication. This strategy consists of subcutaneous injection of irradiated whole tumor cells (rWTC) pulsed with phagocytic agonists (Mannan-BAM), TLR ligands (LTA, Poly (I:C), and R-848), and anti-CD40 agonistic antibody (collectively abbreviated as rWTC-MBTA). We evaluated the therapeutic efficacy of rWTC-MBTA strategy in mouse syngeneic GBM tumor models with GL261 and SB28 cells. In GL261 GBM model, complete regression (CR) of intracranial tumors was achieved in 70% (7/10) of rWTC-MBTA treated animals while none survived in the control group. Of note, the therapeutic efficacy of rWTC-MBTA was abolished in CD4-T and/or CD8-T lymphocyte depleted mice. Immunophenotyping analyses of peripheral lymph nodes and brain tumors of rWTC-MBTA treated mice demonstrated increased antigen presenting cells (dendritic cells and MHC II+ monocytes) and increased cytotoxic IFNγ, TNFα, and granzyme B-secreting CD4-T and CD8-T cells. All three CR mice that were rechallenged with GL261 cells intracranially 14 months after their last rWTC-MBTA treatment resisted tumor development, confirming the establishment of long-term immunological memory. In SB28 GBM model, 80% (8/10) rWTC-MBTA treated mice survived past 95 days after tumor cell implantation without any GBM-related symptoms, with median survival being only 35 days in control groups. In summary, our study demonstrated that rWTC-MBTA strategy can induce potent adaptive immune response against GBM in pre-clinical models. Citation Format: Herui Wang, Rogelio Medina, Juan Ye, Samik Chakraborty, Ondrej Uher, Mitchell Sun, Jan Zenka, Mark R. Gilbert, Karel Pacak, Zhengping Zhuang. Irradiated whole tumor cells pulsed with mannan-BAM, TLR ligands and anti-CD40 antibody serve as a potent tumor cell vaccine against glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 691.

Abstract 4442: Dual benefit of MALT1 blockade in glioblastoma

Abstract Background: Glioblastoma multiforme (GBM) is the most common and aggressive malignant primary brain tumor. Despite advances in treatment modalities, GBM remains largely incurable and new treatment approaches are desperately needed. An innovative strategy for cancer therapy is to combine the inhibition of cancer cell-intrinsic oncogenic signaling with cancer cell-extrinsic immunological activation of the tumor microenvironment (TME). MALT1 represents a candidate target whose inhibition may provide this dual benefit. Originally identified as a proto-oncoprotein in lymphoma, MALT1 has recently also been implicated in multiple solid tumors, including GBM, and significant effort has been made to develop MALT1 protease inhibitors as anti-cancer agents. Interestingly, blockade of MALT1 protease has also been shown to selectively reprogram tumor infiltrating Treg cells into antitumor effector cells. Based on these observations, we hypothesized that in GBM, MALT1 acts both within tumor cells and within cells of the TME to promote tumorigenesis and MALT1 inhibitor treatment could thus have dual benefit. Methods/Results: We assembled a panel of mouse and human GBM cell lines and performed western-blot analysis to show that these cells demonstrate constitutive MALT1 expression and proteolytic activity. MALT1 blockade in GBM cells, using siRNA or MALT1 protease inhibitors, reduces viability and clonogenic potential, suggesting that inhibition of MALT1 could impair tumor cell survival. Single-cell RNAseq data from public datasets demonstrated that myeloid cells have the highest MALT1 expression in the GBM TME. Our data indicate that co-culture of macrophages with GBM cells induces MALT1-NF-κB activation within the macrophages and this is associated with polarization towards an M2-like immunosuppressive phenotype. Additionally, treating primary human or mouse macrophages with MALT1-protease inhibitor prevents GBM-induced M2-polarization, increases M1-polarization and enhances GBM cell killing. In a syngeneic orthotopic mouse model, GBM tumor growth is impaired, and survival is extended when tumor cells are implanted into MALT1-protease dead (PD) host mice (mice which harbor a point mutation in the MALT1-protease catalytic cysteine) as compared to when implanted into wild-type host mice. MALT1-PD mice demonstrate a less immunosuppressive GBM TME with increased M1-macrophages and decreased M2-macrophages, MDSCs and Tregs. Taken together, our findings suggest that inhibiting MALT1 protease in TME cells promotes anti-tumor immunity against brain tumors. Conclusions: Our studies suggest MALT1 protease as a new therapeutic target in GBM whose inhibition could have dual benefit via both direct effect on tumor cells and by reversing the immunosuppressive TME. Citation Format: Juliana Hofstatter Azambuja, Saigopalakrishna S. Yerneni, Gabriela N. Debom, Lisa M. Maurer, Hannah E. Butterfield, Linda R. Klei, Gary Kohanbash, Peter C. Lucas, Linda M. McAllister-Lucas. Dual benefit of MALT1 blockade in glioblastoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4442.

Glioblastoma multiforme growth prediction using a Proliferation-Invasion model based on nonlinear time-fractional 2D diffusion equation

The glioblastoma multiforme (GBM) is the fast-growing and aggressive type of tumor of the brain or spinal cord that is associated with high morbidity and mortality. Therefore, accurate knowledge of the tumor growth process in different time intervals seems necessary to adopt optimal treatment methods. In this study, with a combination of available early stages imaging data and using image processing methods, a time fractional reaction–diffusion equation based on the moving least squares method was implemented for predicting the growth of the GBM tumor model implemented in the mouse brain. The obtained results demonstrate that the Proliferation-Invasion model implemented by a time fractional form shows more agreement with the experimental results. As a result, using a fractional derivative of order α=0.9 results in the lowest prediction error of the tumor surface (less than 1%). In addition, to reducing the cost and side effects of theranostic methods, the presented model will have the possibility to consider the effects of therapeutic factors, such as hyperthermia, radiography, and surgery, on tumor growth. The ability to use the patient’s characteristics in diagnostic and treatment considerations and the development of personalized medicine can also be considered one of the capabilities of the presented model.

Non-invasive prediction of overall survival time for glioblastoma multiforme patients based on multimodal MRI radiomics.

Glioblastoma multiforme (GBM) is the most common and deadly primary malignant brain tumor. As GBM tumor is aggressive and shows high biological heterogeneity, the overall survival (OS) time is extremely low even with the most aggressive treatment. If the OS time can be predicted before surgery, developing personalized treatment plans for GBM patients will be beneficial. Magnetic resonance imaging (MRI) is a commonly used diagnostic tool for brain tumors with high-resolution and sound imaging effects. However, in clinical practice, doctors mainly rely on manually segmenting the tumor regions in MRI and predicting the OS time of GBM patients, which is time-consuming, subjective and repetitive, limiting the effectiveness of clinical diagnosis and treatment. Therefore, it is crucial to segment the brain tumor regions in MRI, and an accurate pre-operative prediction of OS time for personalized treatment is highly desired. In this study, we present a multimodal MRI radiomics-based automatic framework for non-invasive prediction of the OS time for GBM patients. A modified 3D-UNet model is built to segment tumor subregions in MRI of GBM patients; then, the radiomic features in the tumor subregions are extracted and combined with the clinical features input into the Support Vector Regression (SVR) model to predict the OS time. In the experiments, the BraTS2020, BraTS2019 and BraTS2018 datasets are used to evaluate our framework. Our model achieves competitive OS time prediction accuracy compared to most typical approaches.