Primary Brain Cancer Research Articles

Response to Gorter et al. regarding "Acceptability and feasibility of neurocognitive assessments with adults with primary brain cancer and brain metastases: A systematic review".

Response to Gorter et al. regarding "Acceptability and feasibility of neurocognitive assessments with adults with primary brain cancer and brain metastases: A systematic review".

Unveiling the Influence of Tumor Microenvironment and Spatial Heterogeneity on Temozolomide Resistance in Glioblastoma Using an Advanced Human In Vitro Model of the Blood-Brain Barrier and Glioblastoma.

Glioblastoma (GBM) is the most common primary malignant brain cancer in adults with a dismal prognosis. Temozolomide (TMZ) is the first-in-line chemotherapeutic; however, resistance is frequent and multifactorial. While many molecular and genetic factors have been linked to TMZ resistance, the role of the solid tumor morphology and the tumor microenvironment, particularly the blood-brain barrier (BBB), is unknown. Here, the authorsinvestigate these using a complex in vitro model for GBM and its surrounding BBB. The model recapitulates important clinical features such as a dense tumor core with tumor cells that invade along the perivascular space; and a perfusable BBB with a physiological permeability and morphology that is altered in the presence of a tumor spheroid. It isdemonstrated that TMZ sensitivity decreases with increasing cancer cell spatial organization, and that the BBB can contribute to TMZ resistance. Proteomic analysis with next-generation low volume sample workflows of these cultured microtissues revealed potential clinically relevant proteins involved in tumor aggressiveness and TMZ resistance, demonstrating the utility of complex in vitro models for interrogating the tumor microenvironment and therapy validation.

PTEN regulates expression of its pseudogene in glioblastoma cells in DNA methylation-dependent manner

Glioblastoma (GBM) is the most aggressive and frequent type of primary brain cancer in adult patients. One of the key molecular features associated with GBM pathogenesis is the dysfunction of PTEN oncosuppressor. In addition to PTEN gene, humans and several primates possess processed PTEN pseudogene (PTENP1) that gives rise to long non-coding RNA lncPTENP1-S. Regulation and functions of PTEN and PTENP1 are highly interconnected, however, the exact molecular mechanism of how these two genes affect each other remains unclear. Here, we analyzed the methylation level of the CpG islands (CpGIs) in the promoter regions of PTEN and PTENP1 in patient-derived GBM neurospheres. We found that increased PTEN methylation corelates with decreased PTEN mRNA level. Unexpectedly, we showed the opposite trend for PTENP1. Using targeted methylation and demethylation of PTENP1 CpGI, we demonstrated that DNA methylation increases lncPTENP1-S expression in the presence of wild type PTEN protein but decreases lncPTENP1-S expression if PTEN protein is absent. Further experiments revealed that PTEN protein binds to PTENP1 promoter region and inhibits lncPTENP1-S expression if its CpGI is demethylated. Interestingly, we did not detect any effect of lncPTENP1-S on the level of PTEN mRNA, indicating that in GBM cells PTENP1 is a downstream target of PTEN rather than its upstream regulator. Finally, we studied the functions of lncPTENP1-S and demonstrated that it plays a pro-oncogenic role in GBM cells by upregulating the expression of cancer stem cell markers and decreasing cell adhesion.

SYST-14 D2C7 CAR EFFECTIVELY AND SAFELY TREATS EGFRWT AND EGFRVIII-EXPRESSING TUMORS FOLLOWING INTRACRANIAL ADMINISTRATION

Abstract Glioblastoma (GBM) is the most aggressive primary brain cancer with a median survival of less than 16 months. Therefore, significant treatment advances are of critical need. Immunotherapies, such as chimeric antigen receptor (CAR) T cells, have achieved remarkable success in eliminating hematological cancers. Unfortunately, CARs have overall failed to control solid tumors. One major reason for this failure is tumor heterogeneity, a characteristic especially true of GBM. In GBM, EGFRvIII is a commonly targeted tumor antigen; however, only a subset of tumor cells will express EGFRvIII. Thus, EGFRvIII-negative cells easily escape EGFRvIII-targeting CAR therapies. A better approach would be to target multiple antigens or an antigen that is more homogeneously expressed throughout the tumor. More commonly than EGFRvIII expression, glioma cells overexpress the wildtype isoform of EGFR (EGFRwt). Simultaneously targeting EGFRvIII and EGFRwt, instead of targeting each independently, with a CAR will theoretically expand the amount of tumor that will be eliminated by the CAR. Here, we adapted the D2C7scFv that binds both EGFRwt and EGFRvIII into a third generation CAR. D2C7 CAR potently and specifically killed EGFRwt and EGFRvIII-expressing U87 glioma, but not U87 with EGFR knocked out. In xenograft models, intracranially administered D2C7 CAR significantly prolonged survival of mice bearing orthotopic U87vIII, U87 (EGFRwt), and heterogeneous U87/U87vIII tumors compared tocontrols. Additionally, D2C7 CAR was an effective treatment in an orthotopic EGFR-expressing medulloblastoma model. Furthermore, D2C7 CAR treatment led to a significant survival benefit in mice bearing intrancranial A431, an aggressive, EGFR-expressing carcinoma line, a model of metastasis to the brain. Importantly, D2C7 CAR did not show reactivity towards normal tissue with EGFR expression, suggesting a tumor-specific epitope of EGFR is being targeted. Together, these data provide evidence that D2C7 CAR can treat EGFR/EGFRvIII heterogeneous or homogeneous primary or metastatic brain tumors with potentially little-to-no off-tumor toxicity.

The Current Landscape of Glioblastoma Biomarkers in Body Fluids.

Glioblastoma (GBM) is a highly aggressive and lethal primary brain cancer that necessitates early detection and accurate diagnosis for effective treatment and improved patient outcomes. Traditional diagnostic methods, such as imaging techniques and tissue biopsies, have limitations in providing real-time information and distinguishing treatment-related changes from tumor progression. Liquid biopsies, used to analyze biomarkers in body fluids, offer a non-invasive and dynamic approach to detecting and monitoring GBM. This article provides an overview of GBM biomarkers in body fluids, including circulating tumor cells (CTCs), cell-free DNA (cfDNA), cell-free RNA (cfRNA), microRNA (miRNA), and extracellular vesicles. It explores the clinical utility of these biomarkers for GBM detection, monitoring, and prognosis. Challenges and limitations in implementing liquid biopsy strategies in clinical practice are also discussed. The article highlights the potential of liquid biopsies as valuable tools for personalized GBM management but underscores the need for standardized protocols and further research to optimize their clinical utility.

Perivascular invasion of primary human glioblastoma cells in organotypic human brain slices: human cells migrating in human brain.

Glioblastoma (GBM) is an aggressive primary brain cancer. Lack of effective therapy is related to its highly invasive nature. GBM invasion has been studied with reductionist systems that do not fully recapitulate the cytoarchitecture of the brain. We describe a human-derived brain organotypic model to study the migratory properties of GBMIDH-wild type ex vivo. Non-tumor brain samples were obtained from patients undergoing surgery (n = 7). Organotypic brain slices were prepared, and green fluorescent protein (GFP)-labeled primary human GBM IDH-wild type cells (GBM276, GBM612, GBM965) were placed on the organotypic slice. Migration was evaluated via microscopy and immunohistochemistry. After placement, cells migrated towards blood vessels; initially migrating with limited directionality, sending processes in different directions, and increasing their speed upon contact with the vessel. Once merged, migration speed decreased and continued to decrease with time (p < 0.001). After perivascular localization, migration is limited along the blood vessels in both directions. The percentage of cells that contact blood vessels and then continue to migrate along the vessel was 92.5% (-3.9/ + 2.9)% while the percentage of cells that migrate along the blood vessel and leave was 7.5% (-2.9/ + 3.9) (95% CI, Clopper-Pearson (exact); n = 256 cells from six organotypic cultures); these percentages are significantly different from the random (50%) null hypothesis (z = 13.6; p < 10-7). Further, cells increase their speed in response to a decrease in oxygen tension from atmospheric normoxia (20% O2) to anoxia (1% O2) (p = 0.033). Human organotypic models can accurately study cell migrationex vivo. GBM IDH-wild type cells migrate toward the perivascular space in blood vessels and their migratory parameters change once they contact vascular structures and under hypoxic conditions. This model allows the evaluation of GBM invasion, considering the human brain microenvironment when cells are removed from their native niche after surgery.

MGCG regulates glioblastoma tumorigenicity via hnRNPK/ATG2A and promotes autophagy

Glioblastoma (GBM) is the most common malignant primary brain cancer in adults and has constantly been a focus of research. Long noncoding RNAs (lncRNAs) play important roles in the development of cancers. To illustrate the role of lncRNAs in the development of glioblastoma, high-throughput RNA sequencing was performed to obtain the transcripts using three freshly isolated tumor tissue samples from GBM patients and three normal brain tissue samples from the traumatic brain of patients. Then, a lncRNA, MGCG (MGC70870 is expressed at a high level in glioblastoma), which has not been reported previously in GBM, was found to be associated with the prognosis of patients. The results of bioinformatic analysis showed that MGCG was correlated with autophagy and positively correlated with the expression of the autophagy-related gene ATG2A. The data of mass spectrometry demonstrated that the hnRNPK protein was a direct target interacting with MGCG, and MGCG/hnRNPK promoted the development of GBM by enhancing the translation of ATG2A and autophagy. In conclusion, the present study showed that MGCG has the potential to promote the development of GBM and may become a candidate for molecular diagnostics and treatment of tumors.

Screening Ion Channels in Cancer Cells.

Ion channels are critical for cell development and maintaining cell homeostasis. The perturbation of ion channel function contributes to the development of a broad range of disorders or channelopathies. Cancer cells utilize ion channels to drive their own development, as well as to improve as a tumor and to assimilate in a microenvironment that includes various non-cancerous cells. Furthermore, increases in levels of growth factors and hormones within the tumor microenvironment can result in enhanced ion channel expression, which contributes to cancer cell proliferation and survival. Thus, the pharmacological targeting of ion channels is potentially a promising approach to treating solid malignancies, including primary and metastatic brain cancers. Herein, protocols to characterize the function of ion channels in cancerous cells and approaches to analyze modulators of ion channels to determine their impact on cancer viability are described. These include staining a cell(s) for an ion channel(s), testing the polarized state of mitochondria, establishing ion channel function using electrophysiology, and performing viability assays to assess drug potency.

Nanozymes with Peroxidase-like Activity for Ferroptosis-Driven Biocatalytic Nanotherapeutics of Glioblastoma Cancer: 2D and 3D Spheroids Models.

Glioblastoma (GBM) is the most common primary brain cancer in adults. Despite the remarkable advancements in recent years in the realm of cancer diagnosis and therapy, regrettably, GBM remains the most lethal form of brain cancer. In this view, the fascinating area of nanotechnology has emerged as an innovative strategy for developing novel nanomaterials for cancer nanomedicine, such as artificial enzymes, termed nanozymes, with intrinsic enzyme-like activities. Therefore, this study reports for the first time the design, synthesis, and extensive characterization of innovative colloidal nanostructures made of cobalt-doped iron oxide nanoparticles chemically stabilized by a carboxymethylcellulose capping ligand (i.e., Co-MION), creating a peroxidase-like (POD) nanozyme for biocatalytically killing GBM cancer cells. These nanoconjugates were produced using a strictly green aqueous process under mild conditions to create non-toxic bioengineered nanotherapeutics against GBM cells. The nanozyme (Co-MION) showed a magnetite inorganic crystalline core with a uniform spherical morphology (diameter, 2R = 6-7 nm) stabilized by the CMC biopolymer, producing a hydrodynamic diameter (HD) of 41-52 nm and a negatively charged surface (ZP~-50 mV). Thus, we created supramolecular water-dispersible colloidal nanostructures composed of an inorganic core (Cox-MION) and a surrounding biopolymer shell (CMC). The nanozymes confirmed the cytotoxicity evaluated by an MTT bioassay using a 2D culture in vitro of U87 brain cancer cells, which was concentration-dependent and boosted by increasing the cobalt-doping content in the nanosystems. Additionally, the results confirmed that the lethality of U87 brain cancer cells was predominantly caused by the production of toxic cell-damaging reactive oxygen species (ROS) through the in situ generation of hydroxyl radicals (·OH) by the peroxidase-like activity displayed by nanozymes. Thus, the nanozymes induced apoptosis (i.e., programmed cell death) and ferroptosis (i.e., lipid peroxidation) pathways by intracellular biocatalytic enzyme-like activity. More importantly, based on the 3D spheroids model, these nanozymes inhibited tumor growth and remarkably reduced the malignant tumor volume after the nanotherapeutic treatment (ΔV~40%). The kinetics of the anticancer activity of these novel nanotherapeutic agents decreased with the time of incubation of the GBM 3D models, indicating a similar trend commonly observed in tumor microenvironments (TMEs). Furthermore, the results demonstrated that the 2D in vitro model overestimated the relative efficiency of the anticancer agents (i.e., nanozymes and the DOX drug) compared to the 3D spheroid models. These findings are notable as they evidenced that the 3D spheroid model resembles more precisely the TME of "real" brain cancer tumors in patients than 2D cell cultures. Thus, based on our groundwork, 3D tumor spheroid models might be able to offer transitional systems between conventional 2D cell cultures and complex biological in vivo models for evaluating anticancer agents more precisely. These nanotherapeutics offer a wide avenue of opportunities to develop innovative nanomedicines for fighting against cancerous tumors and reducing the frequency of severe side effects in conventionally applied chemotherapy-based treatments.

The safety, feasibility, and efficacy of an 18-week exercise intervention for adults with primary brain cancer – the BRACE study

Purpose To determine the safety, feasibility, and potential effect of an 18-week exercise intervention for adults with primary brain cancer. Materials and methods Eligible patients were 12-26-weeks post-radiotherapy for brain cancer. The individually-prescribed weekly exercise was ≥150-minutes of moderate-intensity exercise, including two resistance-training sessions. The intervention was deemed “safe” if exercise-related, serious adverse events (SAE) were experienced by <10% of participants, and feasible if recruitment, retention, and adherence rates were ≥75%, and ≥75% compliance rates were achieved in ≥75% of weeks. Patient-reported and objectively-measured outcomes were assessed at baseline, mid-intervention, end-intervention, and 6-month follow-up, using generalized estimating equations. Results Twelve participants enrolled (51 ± 19.5 years, 5 females). There were no exercise-related SAEs. The intervention was feasible (recruitment:80%, retention:92%, adherence:83%). Participants completed a median of 172.8 (min:77.5, max:560.8) minutes of physical activity per week. 17% met the compliance outcome threshold for ≥75% of the intervention. Improvements in quality of life (mean change (95% CI): 7.9 units (1.9, 13.8)), functional well-being (4.3 units (1.4, 7.2)), depression (−2.0 units (−3.8, −0.2)), activity (112.8 min (42.1, 183.4)), fitness (56.4 meters (20.4, 92.5)), balance (4.9 s (0.9, 9.0)), and lower-body strength (15.2 kg (9.3, 21.1)) were observed end-intervention. Conclusion Preliminary evidence support that exercise is safe and beneficial to the quality of life and functional outcomes for people with brain cancer.Registration: ACTRN12617001577303

Combination beta-adrenergic blockade and immunotherapy for the treatment of primary and metastatic brain cancer.

e14017 Background: Brain tumors present a unique challenge to immunotherapeutic success, as immune responses in patients with brain tumors are suppressed both within the tumor microenvironment and peripherally. The systemic immunosuppression observed in brain tumor patients limits the capacity of the immune system to respond to immunotherapy. Brain tumor patients, particularly those with primary brain tumors like glioblastoma, represent a population in dire need of more thoughtful, targeted treatment approaches. Through this work we present an immunosuppressive axis specifically activated in the context of intracranial malignancies that inhibits immunotherapeutic success in these patients. We demonstrate that overactive adrenergic signaling is a major barrier to immunotherapeutic success. More specifically, beta-adrenergic signaling is known to suppress immune responses in various contexts. Our data indicate that combining beta-adrenergic blockade with immunotherapy provides a survival benefit in the setting of brain tumors, where immunotherapy alone has proven ineffective. Methods: Using the SEER Medicaid database, we retrospectively examined outcomes in patients with melanoma and lung adenocarcinoma brain metastasis who received checkpoint blockade therapy alone vs those concurrently on beta-blocker therapy. Results: We found that patients receiving combination therapy showed increased overall survival compared to those receiving checkpoint blockade alone. We then validated these findings in preclinical models of both glioma and melanoma brain metastases, demonstrating that combining immunotherapy and propranolol, a highly-prescribed FDA-approved beta-blocker, extended survival. Conclusions: Moving forward, we suggest that combination therapy with propranolol and immunotherapy, particularly checkpoint blockade, represents a promising translational treatment platform for patients with primary or metastatic intracranial malignancies.

Phenotypic diversity of T cells in human primary and metastatic brain tumors revealed by multiomic interrogation

The immune-specialized environment of the healthy brain is tightly regulated to prevent excessive neuroinflammation. However, after cancer development, a tissue-specific conflict between brain-preserving immune suppression and tumor-directed immune activation may ensue. To interrogate potential roles of T cells in this process, we profiled these cells from individuals with primary or metastatic brain cancers via integrated analyses on the single-cell and bulk population levels. Our analysis revealed similarities and differences in T cell biology between individuals, with the most pronounced differences observed in a subgroup of individuals with brain metastasis, characterized by accumulation of CXCL13-expressing CD39+ potentially tumor-reactive T (pTRT) cells. In this subgroup, high pTRT cell abundance was comparable to that in primary lung cancer, whereas all other brain tumors had low levels, similar to primary breast cancer. These findings indicate that T cell-mediated tumor reactivity can occur in certain brain metastases and may inform stratification for treatment with immunotherapy.

O019 Studying telomere biology and genomic instability in gliomas

Abstract Introduction Glioblastoma (GBM) is the most aggressive primary brain cancer. Identifying novel markers which stratify patients and predict response to targeted therapies is a priority. Telomeres are caps on chromosome ends protecting them from aberrant DNA damage response. Telomere length (TL) alterations and fusions are key markers for genomic instability and high-resolution telomere analysis provides powerful prognostic and predictive information in several tumour types. We therefore studied telomeric profiles and fusions in GBM patients and related this to clinical outcome. Methods Tumours from 151 adults with isocitrate dehydrogenase-wildtype GBMs were analysed for TL using the precision High-Throughput Single Telomere Length Analysis technique. 67 patients underwent further multiplex long-range polymerase chain reaction to identify fusions via Southern hybridisation using telomere-adjacent 33P radioisotope-labelled probes. Telomere fusions from 10 tumours that exhibited the highest frequency of fusions were characterised with long-read Nanopore sequencing. Results GBMs display short telomeres with a median length of 4.0kb. Shorter TLs in patients with unmethylated O6-methylguanine DNA methyltransferase status (commonest current biomarker) conferred worse survival (HR 2.13, p = 0.002). 66/67 (98.5%) patients analysed revealed telomeric fusions. Nanopore sequencing validated these events, while confirming the presence of microhomology and telomeric deletion. This mutational spectrum is consistent with utilisation of specific DNA repair pathways in mediating telomere fusion. Conclusion This study provides the first mechanistic evidence of dysfunctional telomeres in adult GBMs and suggests TL analysis may provide independent prognostic information. The presence of telomere fusions indicates significant genomic instability and may favour targeted therapies for patients exhibiting this signature.

Elucidating the cellular mechanisms underlying adoptive cell transfer in models of glioma

Abstract Despite advances in solid tumor biology and oncology, pediatric and adult primary brain cancer and metastasis to the brain harbor dismal prognosis and poor outcomes. One avenue to overcome these clinical challenges is through developing robust immunotherapy to better target the tumor. Our group has previously shown that adoptive cellular therapy (ACT) provides therapeutic benefit against central nervous system (CNS) malignancies, namely medulloblastoma, brain stem glioma and glioblastoma. In this study, we characterized cell cycling differences of immune cellular sub-populations in peripheral lymphoid and tumor tissue compartments in vivo. ACT was conducted in orthotopic KR158 luciferase tumor-bearing mice, a syngeneic murine glioma model. Following completion of ACT, bromodeoxyuridine (BRDU) was administered to mice 12-hours prior to tissue collection and flow cytometry was utilized to measure the level of BRDU incorporation. 7-aminoactinomycin D was used in conjunction with BRDU to provide insight into all phases of the cell cycle. We observed significant differences in cycling populations of myeloid derived suppressor cells (MDSC) and T cells. In mice receiving ACT, MDSCs found in secondary lymphoid tissues were significantly more proliferative. In the tumor microenvironment (TME), proliferating MDSCs were significantly reduced compared to mice that did not receive treatment. Frequencies of proliferating CD4+ and CD8+ T-cells were significantly increased in cervical lymph node and TME, but reduced in spleen. These findings suggest that ACT changes immune cycling and migration dynamics in lymphoid tissue and TME to potentially promote antitumor T-cell responses and minimize tumor-mediated immunosuppression. 5R01NS112315-04

Glioblastoma Microenvironment and Invasiveness: New Insights and Therapeutic Targets.

Glioblastoma (GBM) is the most common and malignant primary brain cancer in adults. Without treatment the mean patient survival is approximately 6 months, which can be extended to 15 months with the use of multimodal therapies. The low effectiveness of GBM therapies is mainly due to the tumor infiltration into the healthy brain tissue, which depends on GBM cells' interaction with the tumor microenvironment (TME). The interaction of GBM cells with the TME involves cellular components such as stem-like cells, glia, endothelial cells, and non-cellular components such as the extracellular matrix, enhanced hypoxia, and soluble factors such as adenosine, which promote GBM's invasiveness. However, here we highlight the role of 3D patient-derived glioblastoma organoids cultures as a new platform for study of the modeling of TME and invasiveness. In this review, the mechanisms involved in GBM-microenvironment interaction are described and discussed, proposing potential prognosis biomarkers and new therapeutic targets.

Abstract 106: Intratumoral heterogeneity of glioblastoma is attributed to precancerous cells derived from neural stem cells

Abstract Glioblastoma (GBM) is the most common and aggressive primary brain cancer in adults. We and other groups have identified mutation-harboring neural stem cells (NSCs) in the subventricular zone (SVZ) as cells-of-origin carrying driver mutations (Lee et al, Nature 2018). However, little is known about the evolutional process by which mutation-harboring NSCs in the SVZ transform into distant cancer cells with a high degree of molecular heterogeneity. Here, using a spontaneous, somatic mouse model that recapitulates human GBM arising from NSCs that carry driver mutations, we show that mutation-harboring NSCs transform into precancerous cells through oligodendrocyte progenitor cell (OPC) lineage specification during tumor evolution. These precancerous cells show dysregulated translation and/or modification of extracellular matrix (ECM) prior to tumor formation. They subsequently give rise to GBMs with intratumoral heterogeneity exhibiting multiple developmental cell states as in human GBM, and also show activation of additional transcriptional programs, including immune evasion, ECM remodeling, epithelial-mesenchymal transition, and proliferation. Importantly, we further identified precancerous cell populations carrying driver mutations, namely gain of chromosome 7 and loss of chromosome 10 in tumor-free SVZ tissues from GBM patients with intratumoral heterogeneity. These human precancerous cells indeed exhibited OPC and neural progenitor cell-like expression patterns similar to those in our spontaneous GBM mouse model. Thus, our results demonstrate that cell-type specification of precancerous cells with oncogenic transcriptional programs underlie evolution of GBM from mutation-harboring NSCs and intratumoral heterogeneity. Citation Format: Jeong Ho Lee, Hyun Jung Kim, Seok-Gu Kang. Intratumoral heterogeneity of glioblastoma is attributed to precancerous cells derived from neural stem 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 106.

Abstract 1081: Co-targeting CK1epsilon and PIK3CB/p110beta to treat glioblastoma

Abstract The purpose of this study is to determine whether co-inhibition of CK1epsilon and PIK3CB/p110β is an effective therapeutic treatment for Glioblastoma (GBM). GBM is the most common and malignant primary brain cancer in adults. GBM has a dismal prognosis of death within 6 months if left untreated, thus there is a clinically unmet need for new and effective treatments. CK1epsilon has been identified as a GBM survival kinase gene. CK1epsilon promotes growth of GBM cells by inhibiting β-catenin. However, blocking CK1epsilon alone fails to completely block tumor growth perhaps because β-catenin can be regulated by other kinases. PIK3CB/p110β is another GBM survival kinase gene which also acts upstream of β-catenin. As seen with CK1epsilon, blocking PIK3CB/p110β alone also fails to completely block tumor growth. It is possible that blocking either CK1epsilon or PIK3CB/p110β alone does not substantially activate β-catenin to induce massive GBM cell death, thus limiting their therapeutic efficacy as a single agent. It is therefore imperative to investigate if co-targeting CK1epsilon and PIK3CB/p110β yields a synergistic inhibitory effect on GBM cell growth. GBM cells were treated with either DMSO (control), IC261 (chemical inhibitor of CK1epsilon), AZD6482 (chemical inhibitor of PIK3CB/p110β), or both IC261 and AZD6482. Cell viability was measured using the MTS viability assay. Cell viability for the treatment groups were as follows: AZD6482 (88.81%), IC261 (66.78%), and combination of AZD6482+IC261 (42.59%). Statistical analysis of drug synergy using the Bliss independence model yielded an Excess Over Bliss score greater than 0%, indicating a synergistic effect. To further elucidate the mechanism of GBM cell death, immunoblotting will also be performed to detect β-catenin activity after inhibition of CK1epsilon and PIK3CB/p110β. Overall, preliminary results show that co-inhibition of CK1epsilon and PIK3CB/p110β with chemical inhibitors yields synergistic GBM cell death. Citation Format: Eileen Xu. Co-targeting CK1epsilon and PIK3CB/p110beta to treat 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 1081.

Abstract 4917: High-frequency irreversible electroporation ablation of glioma alters extracellular vesicles and disrupts the blood-brain barrier endothelium

Abstract High-frequency irreversible electroporation (H-FIRE) is a nonthermal tumor ablation technology that kills cancer cells via pulsed electric fields. H-FIRE has been shown to precisely and nonthermally ablate brain tumors while transiently disrupting the peritumoral blood-brain barrier (BBB). The enhanced BBB permeability post-tumor ablation can be exploited to enhance therapeutic delivery to invasive tumor margins, but the mechanisms of H-FIRE-induced BBB disruption remain incompletely characterized. We hypothesize that bystander effects of H-FIRE tumor cell ablation, specifically the release of tumor-derived extracellular vesicles (TDEVs), mediate peritumoral BBB endothelium disruption. F98 glioma and bEnd.3 cerebral endothelial cell lines modelled primary brain cancer and the BBB endothelium, respectively. F98 glioma cells were treated in vitro with sham treatment, a sub-ablative (1,500 V/cm), or an ablative (3,000 V/cm) electric field dose of H-FIRE, and TDEVs were isolated from the supernatants via filtration and ultracentrifugation. Post-H-FIRE TDEVs were characterized via nanoparticle tracking analysis and transmission electron microscopy, with ablative doses of H-FIRE resulting in decreased release of TDEVs compared to sub-ablative H-FIRE and sham treatment. Post-H-FIRE TDEVs were then applied to Transwell models of the BBB endothelium to evaluate the effect of H-FIRE-induced TDEVs on BBB endothelium permeability. TDEVs released after the ablative H-FIRE dose (3,000 V/cm) significantly increased permeability of the BBB endothelium in vitro compared to TDEVs released after sub-ablative and sham H-FIRE treatment. TDEVs were then fluorescently labelled with CFSE, and confocal microscopy was used to characterize internalization of post-H-FIRE TDEVs by cerebral endothelial cells. The TDEVs released after ablative doses of H-FIRE were significantly internalized by bEnd.3 cerebral endothelial cells, while TDEVs released after sub-ablative and sham treatment were not internalized. The proteomic payloads of the post-H-FIRE TDEVs were characterized using mass spectrometry, and clustering analysis demonstrated that the in vitro BBB-modulatory TDEVs released after 3,000 V/cm H-FIRE had distinct proteomic payloads compared to the non-BBB-modulatory TDEV populations released after sham and 1,500 V/cm H-FIRE treatment. Proteins associated with proteasomal degradation, cellular adhesion, and modulation of junctional integrity were increased in the BBB-modulatory group of TDEVs. Taken together, our results suggest that H-FIRE ablation of glioma significantly alters the proteomic cargo of TDEVs to increase internalization of TDEVs by cerebral endothelial cells and increase permeability of the BBB endothelium. Citation Format: Kelsey Murphy, Kenneth Aycock, Spencer Marsh, Alayna Hay, Christine Chang, Shay Bracha, Robert Gourdie, Rafael Davalos, John H. Rossmeisl, Nikolaos Dervisis. High-frequency irreversible electroporation ablation of glioma alters extracellular vesicles and disrupts the blood-brain barrier endothelium. [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 4917.

Mechanical nanosurgery of chemoresistant glioblastoma using magnetically controlled carbon nanotubes.

Glioblastoma (GBM) is the most common and aggressive primary brain cancer. Despite multimodal treatment including surgery, radiotherapy, and chemotherapy, median patient survival has remained at ~15 months for decades. This situation demands an outside-the-box treatment approach. Using magnetic carbon nanotubes (mCNTs) and precision magnetic field control, we report a mechanical approach to treat chemoresistant GBM. We show that GBM cells internalize mCNTs, the mobilization of which by rotating magnetic field results in cell death. Spatiotemporally controlled mobilization of intratumorally delivered mCNTs suppresses GBM growth in vivo. Functionalization of mCNTs with anti-CD44 antibody, which recognizes GBM cell surface-enriched antigen CD44, increases mCNT recognition of cancer cells, prolongs mCNT enrichment within the tumor, and enhances therapeutic efficacy. Using mouse models of GBM with upfront or therapy-induced resistance to temozolomide, we show that mCNT treatment is effective in treating chemoresistant GBM. Together, we establish mCNT-based mechanical nanosurgery as a treatment option for GBM.

Trajectories of participation in daily life among individuals newly diagnosed with cancer: A 5-month longitudinal study.

To determine how participation in daily life is impacted during the first six months following a new cancer diagnosis and to identify risk factors for participation restrictions. Patient-reported outcomes (PROs) were used to suggest referrals to rehabilitation services. Participants (n = 123) were adults (> 18years) with the newly diagnosed primary brain, breast, colorectal, or lung cancer. PROs were collected at baseline (within 30days of diagnosis/treatment initiation), two and five months post baseline. Daily life participation was assessed through the community participation indicators (CPI) (score range: 0-1) and patient-reported outcome measurement information system (PROMIS) ability to participate, (score range: 20-80; mean: 50, SD: 10). PROMIS-43 profile was also completed. Linear mixed-effect models with random intercept evaluated change in participation over time. The baseline total sample mean CPI score was 0.56; patients reported mildly impaired participation based on PROMIS scores (baseline: 46.19, 2-month follow-up: 44.81, 5months: 44.84). However, no statistically significant changes in participation were observed over the study period. Risk factors for lower participation included receiving chemotherapy, lower physical function, higher anxiety and fatigue, and reduction in employment, p < 0.05. PROs indicated that roughly half of the participants may benefit from physical or occupational therapy or mental health support, but only 20-36% were referred by their medical team. People newly diagnosed with cancer experience impaired participation, but they are infrequently referred to supportive services such as rehabilitation. The use of PROs to assess participation, physical function, and mental health can promote access to supportive care services by identifying patients who may benefit from rehabilitation beyond those identified through routine clinical care.