bluuebunny/crossref_metadata_2025 huggingface dataset:
SURG-09. SUCCESSFUL SAFETY AND EFFICACY OF GAMMATILE INTRACRANIAL BRACHYTHERAPY IMPLANTED DURING AWAKE CRANIOTOMY
Authors: McClelland III Shearwood , Gardner Ulysses , Le Yi , Ng Sook Kien , Shah Mitesh , Watson Gordon
Published: November 2021

INTRODUCTION

GammaTile intracranial brachytherapy utilizing cesium-131 seeds has demonstrated encouraging safety and local control results in a single-arm precommercial study, and recently received Food and Drug Administration clearance. The authors report the first case of GammaTile intraoperative brachytherapy performed during an awake craniotomy.

METHODS

A 50-year-old man suffered a generalized tonic-clonic seizure while a vehicle passenger. MRI revealed a 2.8 cm left lateral frontal lesion nearing his Broca’s area. Open brain biopsy revealed IDH-wildtype MGMT unmethylated GBM. Unfortunately, despite several interventions (awake craniotomy, adjuvant chemoradiation with temozolomide, Avastin, tumor treating fields) he suffered tumor progression near the left parietal resection cavity. Due to the location of this tumor, re-resection was planned with awake craniotomy and language mapping. A preoperative planning session involving Radiation Oncology and Neurosurgery identified the area of the expected postoperative bed, and consequently five GammaTiles were ordered, each containing 4 cesium-131 3.5 U seeds.

RESULTS

During surgery, once the tumor was mapped, bipolar stimulation was performed while the patient spoke in complete sentences until going into speech arrest on the posterior edge of the gyrus, indicative of language cortex. Following this mapping, microsurgical maximal safe resection occurred, after which areas at risk for tumor residual/recurrence were determined in consultation with Radiation Oncology. Subsequently, Neurosurgery placed all five GammaTiles (20 cesium-131 seeds total) in customized forward fashion to optimally cover the dosimetric needs of these areas. Following GammaTile placement, closure was completed and radioactive surveys of the room remained within state statue. Postoperative dosimetry yielded excellent coverage, and speech function was maintained.

CONCLUSIONS

The first reported case of GammaTile intraoperative brachytherapy during awake craniotomy supports the safety and feasibility of this treatment strategy. This case indicates that for patients with tumors adjacent to eloquent cortex, awake craniotomy can allow for maximum safe resection and implantation of intraoperative brachytherapy.
TAMI-03. PROGNOSTIC SIGNIFICANCE OF NEUTROPHIL-TO-LYMPHOCYTE RATIO (NLR) IN PATIENTS WITH BRAIN METASTASES FROM DIFFERENT TUMOR ORIGINS
Authors: Deng Guanhua , Wen Lei , Zhou zhaoming , Shan Changguo , Lai Mingyao , Zhou Cheng , Cai Linbo
Published: November 2021

PURPOSE

Brain metastases (BMs) represent the most common adult intracranial malignancy. The prognosis of BMs is subject to many factors, i.e., the number, size and locations of the metastatic sites, tumor origins, pathologic types, gene mutation status, metastatic sites, and KPS etc. This study aimed to evaluate the prognostic value of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) in brain metastases.

METHODS

A total of 480 patients diagnosed with brain metastases from a wide range of tumor origins, i.e., NSCLC, SCLC, breast cancer, melanoma, prostate, kidney, gastrointestinal cancer, cervical carcinoma, ovarian cancer, choriocarcinoma of uterus were retrospectively analyzed. Pre-radiotherapy NLR, PLR, and LMR were calculated as total neutrophil/lymphocyte, platelet/Lymphocyte, lymphocyte/monocyte, respectively. Survival rates were estimated using the Kaplan-Meier survival analysis. Cox regression models were used to identify independent prognostic factors.

RESULTS

The median overall survival (OS) was 14.4 months [95%CI: 13.4-15.5]. The median overall survival after radiotherapy was significantly different between patients with NLR< 4 and those with NLR≥4 (OS 16.3 mo. vs. 12.2 mo., P< 0.0001). No signiﬁcant difference was observed between PLR vs. OS, and LMR vs. OS (PLR< 180: HR=1.221, P=0.240; LMR< 4: HR=0.753, P=0.141). The Cox regression model for the continuous metric values revealed that the NLR increased every 1.0 was associated with additional 5.9% of fatal risk (HR: 1.059; 95%CI = 1.033–1.087, P< 0.0001). NLR was validated as an independent prognostic factor for risk of death after adjusting for sex, age, and KPS.

CONCLUSIONS

We revealed pre-treatment NLR is an independent prognostic factor in patients with brain metastases for poor OS, independent of different tumor origins. The NLR warrants further studies using sub-group analysis and validation in external cohorts. Future studies in this parameter have a potential to facilitate more precise risk-stratifications to guide personalized treatment for BM.
TAMI-20. GLIOMA CELLS REPROGRAM SERINE-DEPENDENT ONE-CARBON METABOLISM TO SURVIVE GLUTAMINE STARVATION
Authors: Tanaka Kazuhiro , Nagashima Hiroaki , Fujita Yuichi , Hashiguchi Mitsuru , Sasayama Takashi
Published: November 2021

Cancer cells optimize nutrient utilization to supply energetic and biosynthetic pathways. This metabolic process also includes redox maintenance and epigenetic regulation through nucleic acid and protein methylation, which enhance tumorigenicity and clinical resistance. However, less is known about how cancer cells exhibit metabolic flexibility to sustain cell growth and survival from nutrient starvation. Here, we find that serine and glycine levels were higher in low-nutrient regions of tumors in glioblastoma multiforme (GBM) patients than they were in other regions. Metabolic and functional studies in GBM cells demonstrated that serine availability and one-carbon metabolism support glioma cell survival following glutamine deprivation. Serine synthesis was mediated through autophagy rather than glycolysis. Gene expression analysis identified upregulation of methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) to regulate one-carbon metabolism in GBM patient-derived sphere cells as well as in GBM cells. In clinical samples, MTHFD2 expression was highest in the nutrient-poor areas around “pseudopalisading necrosis.” Genetic suppression of MTHFD2 and autophagy inhibition caused tumor cell death and growth inhibition of glioma cells upon glutamine deprivation. These results may have important implications for serine-dependent one-carbon metabolism for glioma cells to survive glutamine starvation and suggest a new therapeutic strategy for patients with malignant glioma.
TAMI-30. THERAPY INDUCED REPROGRAMMING DRIVES GLIOMA VASCULAR TRANSDIFFERENTIATION AND TUMOR RECURRENCE
Authors: Muthukrishnan Sree Deepthi , Kawaguchi Riki , Nair Pooja , Prasad Rachna , Alvarado Alvaro , Qin Yue , Condro Michael , Kornblum Harley
Published: November 2021

Therapy-resistant glioma cells elicit phenotypic plasticity leading to aggressive tumor recurrence. Here, we employed single-cell and whole transcriptomic analyses to uncover that a standard glioma treatment, radiation induces a dynamic shift in functional states of glioma cells allowing for acquisition of mesenchymal-like and vascular-like phenotypes. The predominant phenotype switch induced by radiation in surviving tumor cells is transdifferentiation to endothelial-like and pericyte-like cells. The transdifferentiated cells in turn promote proliferation of radiated tumor cells, and their selective depletion results in reduced tumor growth and recurrence post-treatment. The acquisition of vascular-like phenotype is driven by increased chromatin accessibility in vascular genes, and blocking P300-mediated histone acetyltransferase activity prior to radiation treatment inhibits vascular transdifferentiation and tumor growth. Our findings indicate that radiation therapy reprograms tumor cells driving vascular transdifferentiation, and highlights HAT inhibitors as potential therapeutic target for preventing GBM relapse
TAMI-40. PEDIATRIC H3K27M MUTANT GLIOMAS UNDERGO METABOLIC REPROGRAMMING THAT CAN BE LEVERAGED FOR NON-INVASIVE METABOLIC IMAGING
Authors: Tran Meryssa , Batsios Georgios , Taglang Céline , Gillespie Anne Marie , Nazarian Javad , Mueller Sabine , Viswanath Pavithra
Published: November 2021

Diffuse midline gliomas (DMGs) are a universally lethal form of childhood cancer. The infiltrative nature of DMGs makes them difficult to visualize by conventional magnetic resonance imaging. Genomics studies indicate that DMGs are driven by unique histone H3K27M mutations that result in broad epigenetic dysregulation. Many of the resulting changes in gene expression have the potential to induce metabolic reprogramming, which has been identified as a hallmark of cancer. The goal of this study was to dissect metabolic reprogramming in preclinical DMG models in order to identify novel magnetic resonance spectroscopy (MRS)-detectable metabolic biomarkers that can be exploited for non-invasive imaging. First, we used 1H-MRS, which reports on steady-state metabolism, to examine H3K27M mutant SF7761 cells and H3 wild-type normal human astrocytes (NHA). Lactate, glutathione and phosphocholine, which are involved in glycolysis, redox and phospholipid metabolism respectively, were elevated in SF7761 cells relative to NHAs. Mechanistically, these metabolic alterations were associated with upregulation of key enzymes including hexokinase 2, glutamate cysteine ligase and choline kinase a. Importantly, in vivo 1H-MRS showed elevated lactate, glutathione and total choline (combined signal from choline, phosphocholine and glycerophosphocholine) in mice bearing orthotopic SF7761 tumors relative to tumor-free controls. We then examined alterations in dynamic metabolic pathways in our models. Using thermally-polarized 13C-MRS, we identified elevated production of [2-13C]-lactate from [2-13C]-glucose in SF7761 cells relative to NHAs. Hyperpolarized 13C-MRS is a method of enhancing the 13C-MR signal such that metabolic fluxes can be interrogated with high sensitivity. Hyperpolarized [1-13C]-pyruvate flux to [1-13C]-lactate non-invasively monitors glycolysis and is in clinical trials in adult glioma patients. Importantly, hyperpolarized [1-13C]-pyruvate metabolism to lactate was elevated in SF7761 cells relative to NHAs. Collectively, our studies suggest that H3K27M mutant DMGs undergo reprogramming of glucose, redox and phospholipid metabolism that can be leveraged for non-invasive 1H- and hyperpolarized 13C-MRS-based imaging.
TAMI-57. INDUCTION OF FERROPTOSIS PROMOTES IMMUNOGENIC CELL DEATH AND ACTIVATION OF THE IMMUNE MICROENVIRONMENT IN GLIOMA
Authors: Argenziano Michael , Banu Matei , Dovas Athanassios , Zhao Wenting , Furnari Julia , Higgins Dominique , Upadhyayula Pavan , Mahajan Aayushi , Humala Nelson , Sims Peter , Bruce Jeffrey N , Canoll Peter
Published: November 2021

Gliomas are immune cold tumors. Effective therapeutic strategies capable of inducing an immune response are lacking.Here we present evidence that ferroptosis, a form of iron-mediated lipid peroxidation-based cell death, may promote anti-tumor immunity via stimulation of phagocytosis and pro-inflammatory activities in microglia. While ferroptosis has shown promise in induction of glioma cell death, the immunogenic and microenvironmental effects of glioma ferroptosis are poorly understood. First, we tested the in vitro effects of the glutathione peroxidase 4 (GPX4) inhibitor RSL3, a ferroptosis inducer, on murine glioma cell lines. Using flow cytometry, we discovered that RSL3 treatment led to membrane translocation of the pro-phagocytic antigen calreticulin, known hallmark of immunogenic cell death, by an average log2-fold-change of 2.53 (p= 0.03) compared to DMSO-treated controls. This effect correlated with lipid peroxidation, as assessed by BODIPY-C11 staining. To further test the effects of ferroptosis on glioma cell-microglia crosstalk, we prepared acute brain tumor slices from both mouse and human glioma samples, and treated them with RSL3. Quantification of immunofluorescent staining from three independent human slice cultures after RSL3 treatment demonstrated a significant increase in calreticulin abundance as compared to control (p < 0.001). Importantly, this effect was significantly diminished with addition of ferrostatin, an inhibitor of ferroptosis, demonstrating that ferroptosis induction was directly responsible for calreticulin translocation. Single-cell RNAseq on mouse and human acute glioma slice cultures treated with RSL3 demonstrated significant overexpression of calreticulin in the tumor population, and positive enrichment of interferon signaling, antigen presentation, and phagocytosis ontologies in both tumor and myeloid compartments. These findings suggest that ferroptosis-induced translocation of calreticulin on the surface of glioma cells promotes activation of the local immune microenvironment by increasing tumor antigen presentation and pro-inflammatory cytokine release by tumor-associated microglia. Thus, ferroptosis-inducing drugs may promote anti-tumor immunity through the activation of immunogenic cell death signals.
TAMI-63. INHIBITION OF LINEAGE STATES WITHIN GBM OVERCOMES CHEMO-RESISTANCE
Authors: Joseph Kevin , Maier Julian , Ravi Vidyha , Beck Jürgen , Hofmann Ulrich , Heiland Dieter Henrik , Schnell Oliver
Published: November 2021

OBJECTIVE

Novel insights into the developmental trajectory exhibited by glioblastoma (GBM) have shown that it has the capability to respond to its microenvironment by clonal selection of specific transcriptional phenotypes. Using the same mechanisms, malignant GBM develop intrinsic mechanisms to resist chemotherapeutic treatments. In this study, we determine the role of the metabotropic glutamate receptor 3 (mGluR3) in chemoresistance and show that inhibition of mGluR3 leads to significant loss of tumor growth volume when concomitantly treated with Temozolomide.

METHODS

Transcriptomic analysis was carried out post mGlur3 receptor inhibition using LY341495 (100nM), to study loss of transcriptional programs. Morphological and cellular kinetic analysis was carried out post inhibition, to determine apoptosis/necrosis rate, when combined with Temozolomide. The efficacy of the treatment within a human like environment was assessed using our novel human cortical GBM model.

RESULTS

We present transcriptional and morphological evidence that mGluR3 inhibition using LY341495 leads to loss of both lineage (FDR< 0.01) and reactive (FDR< 0.01) transcription programs. This leads to a loss of ability to evade cytotoxicity when combined with Temozolomide treatment, validated using kinetic apoptosis (p< 0.01). When our cortical GBM model was used to study the effect of treatment within the appropriate microenvironment, we see that the combination therapy leads to a significant reduction in tumor growth (p< 0.01) over the course of 10 days.

CONCLUSION

Through the integration of diversified molecular-biological analyses, we illustrate a new picture of how glutamate signaling via mGluR3 interacts with phenotypical GBM transcriptional programs to evade effective therapy, the inhibition of which leads to loss of chemo-resistance.
TAMI-67. INVESTIGATION OF THE COMPLEMENT SYSTEM IN THE IRRADIATED BRAIN TUMOR MICROENVIRONMENT
Authors: Rosberg Rebecca , Smolag Karolina , Pantazopoulou Vasiliki , Blom Anna , Pietras Alexander
Published: November 2021

Glioblastoma is the most common and aggressive primary brain tumor in adults. Despite treatment through surgery, irradiation and chemotherapy all patients suffer recurrence of treatment-resistant tumors and the survival prognosis remains poor. The recurrence of tumors is driven by the invasive nature of the tumor and appears to be related to cells with stem like characteristics that are present in perivascular and hypoxic niches. Previous studies from our lab showed that astrocytes grown in hypoxic or irradiated conditions increase the stemness of glioma cells. The altered behavior of the astrocytes leads to increased cell size and a change in secreted cytokines. Reactive astrocytes are important in other central nervous system (CNS) diseases involved in tissue repair such as traumatic brain injury and Alzheimer’s disease. Interestingly, in several neurological diseases, reactive astrocytes upregulate complement proteins, especially complement component 3 (C3). However, it remains relatively unexplored how these complement proteins in stromal astrocytes are expressed in glioblastoma. Tissue sections from our glioma mouse model shows presence of C3 around hypoxic areas where there is an abundance of astrocytes. We have also shown that astrocytes grown at 21%, 1% and 0.1% oxygen upregulate complement protein C3 as well as other proteins associated with a more extensive infiltrative phenotype of glioblastoma. Datasets with human patients showed that C3 expression was correlated with higher grade tumors and that patients with tumors expressing C3 had more risk to get new tumors after primary treatment (including but not limited to radiotherapy). In this ongoing project, we are investigating whether activation of the complement system in the tumor microenvironment contributes to tumor progression. The upregulation of C3 in astrocytes in hypoxic conditions could therefore through local complement activation possibly led to tumor promoting signaling leading to beneficial survival of therapies of nearby glioma cells.
TAMI-72. DIVERSITY OF CELLULAR COMMUNICATION IN GLIOBLASTOMA
Authors: Joseph Kevin , Vollmer Lea , Ravi Vidyha , Beck Jürgen , Hofmann Ulrich , Schnell Oliver , Heiland Dieter Henrik
Published: November 2021

OBJECTIVE

Owing to recent advances in understanding of the active functional states exhibited within glioblastoma (GBM), intra-tumoral cellular signaling has moved into focus of neuro-oncology. In this study, we aim to explore the diversity of transcellular signaling and investigate correlations between transcriptional dynamics and functional signaling.

METHODS

Electrophysiological characterization of GBM was carried out using planar microelectrodes and Ca2+ imaging, in both 2D cell culture as well as in our novel human cortical GBM model. Exposure to physiologically relevant conditions present within the tumor was carried out to identify specific signaling cells of interest and capture the signaling diversity in response to environmental conditions. Transcriptional dynamics and plasticity were examined by means of scRNA-sequencing with CRISPR based perturbation, spatial transcriptomics and deep long-read RNA-sequencing.

RESULTS

Electrophysiological profiles of multiple primary GBM cell lines revealed characteristics of scale-free networks (R2=0.875), confirmed in both 2D culture as well as a human neocortical GBM model. When GBM was cultured in a “in-vivo” like environment, basal activity was significantly higher (50%, p=0.01). Cellular signaling was directly correlated to changes in the environment, like hypoxia or glutamatergic activation, and total inhibition of electrical signaling required the usage of synaptic inhibitors. Using single-cell RNA sequencing and proteomics, several synaptogenesis related genes were identified to play a crucial role in the lineage states present in GBM. CRISPR based perturbation of these genes resulted in alterations in cellular morphology and decreased cellular connectivity (p< 0.01), with loss of scale free features (R2=0.35), and transcriptomic loss of developmental lineages (FDR< 0.01), leading to significant inhibition of GBM stress response.

CONCLUSION

Our findings highlight the role of electrical signaling in glioblastoma. Cellular stressors induce intercellular signaling, leading to transcriptional adaptation suggesting that there exists a highly complex and powerful mechanism for dynamic transcriptional state adaptation.
TAMI-74. SPATIOTEMPORAL MULTI-OMIC LANDSCAPE OF HUMAN MEDULLOBLASTOMA AT SINGLE CELL RESOLUTION
Authors: Liu Hailong , Qiu Xiaoguang , Jiang Tao
Published: November 2021

Medulloblastoma is the most common malignant childhood tumor type with distinct molecular subgroups. While advances in the comprehensive treatment have been made, the mortality in the high-risk group is still very high, driven by an incomplete understanding of cellular diversity. Here we use single-nucleus RNA expression, chromatin accessibility and spatial transcriptomic profiling to generate an integrative multi-omic map in 40 human medulloblastomas spanning all molecular subgroups and human postnatal cerebella, which is supplemented by the bulk whole genome and RNA sequences across 300 cases. This approach provides spatially resolved insights into the medulloblastoma and cerebellum transcriptome and epigenome with identification of distinct cell-type in the tumor microenvironment. Medulloblastoma exhibited three tumor subpopulations including the quiescent, the differentiated, and a stem-like (proliferating) population unique to cancer, which localized to an immunosuppressive-vascular niche. We identified and validated mechanisms of stem-like to differentiated process among the malignant cells that drive tumor progression. Integration of single-cell and spatial data mapped ligand-receptor networks to specific cell types, revealing stem-like malignant cells as a hub for intercellular communication. Multiple features of potential immunosuppression and angiogenesis were observed, including Treg cells and endothelial cells co-localization in compartmentalized tumor stroma. Collectively, our study provides an integrative molecular landscape of human medulloblastoma and represents a reference to advance mechanistic and therapeutic studies of pediatric neuro-oncological disease.
TMOD-01. AN IN VIVO FUNCTIONAL GENOMICS SCREEN TO IDENTIFY NOVEL DRIVERS OF LUNG-TO-BRAIN METASTASIS
Authors: Aghaei Nikoo , Lam Fred C , Kasper Ekkhard , Venugopal Chitra , Singh Sheila K
Published: November 2021

INTRODUCTION

Brain metastases, the most common tumors of the central nervous system, occur in approximately 20% of primary adult cancers. In particular, 40% of patients with non-small cell lung cancer develop brain metastasis. As systemic therapies for the treatment of non-small cell lung cancer become increasingly effective at controlling primary disease, patients are ironically succumbing to their brain metastases. This highlights a large unmet need to develop novel targeted therapies for the treatment of lung-to-brain metastases (LBM). We hypothesize that an in vivo functional genomic screen can identify novel genes that drive LBM.

METHODS

To do this, we developed a patient-derived xenograft (PDX) mouse model of LBM using patient lung cancer cell lines. This PDX model of LBM enables the use of fluorescent and bioluminescent in vivo imaging to track the progression of lung tumor and brain metastases.

RESULTS

We have performed an in vivo genome-wide CRISPR activation screening to identify novel drivers of LBM. We will derive candidate genes through mouse brain and lung tissue sequencing after mice reach endpoint.

EXPECTED AREA OF FINDINGS

This platform will lead to potential therapeutic targets to prevent the formation of LBM and prolong the survival of patients with non-small cell lung cancer.

LIMITATIONS

There may be limitations in getting candidate hits that overlap in all mice in our first replicate. This can be remedied by conducting the in vivo screen in at least three biological replicates.

CONCLUSION

To the best of our knowledge, this is the first genome-wide in vivo CRISPR activation screen searching for drivers of LBM using a PDX animal model. This study can provide a framework to gain a deeper understanding of the regulators of BM formation which will hopefully lead to targeted drug discovery.
TMOD-25. LATENT SOX9-POSITIVE CELLS BEHIND MYC-DRIVEN MEDULLOBLASTOMA RELAPSE
Authors: Borgenvik Anna , Bolin Sara , Savov Vasil , Holmberg Karl O , Zhao Miao , Rosén Gabriela , Hutter Sonja , Garancher Alexandra , Rahmanto Aldwin Suryo , Bergström Tobias , Mainwaring Oliver , Sattanino Damiana , Verbaan Annemieke D , Rusert Jessica , Sundström Anders , Dang Yonglong , Wenz Amelie , Richardson Stacey , Fotaki Grammatiki , Giraud Geraldine , Hill Rebecca , Dubuc Adrian , Kalushkova Antonia , Remke Marc , Cancer Matko , Jernberg-Wiklund Helena , Chen xingqi , Taylor Michael D , Sangfelt Olle , Clifford Steven , Schüller Ulrich , Wechsler-Reya Robert , Weishaupt Holger , Swartling Fredrik
Published: November 2021

Tumor recurrence developing from therapy resistance, immune escape and metastasis is the leading cause of death in medulloblastoma, the most frequent malignant pediatric brain tumor. Amplification of MYC genes is the most common genetic alteration in Group 3 and Group 4 subgroups that constitute two thirds of medulloblastoma. SOX9 is a transcription factor present in stem cells in the normal brain but is limited to rare, quiescent cells in medulloblastoma patients with MYC gene amplifications. By studying paired primary-recurrent patient samples and patient-derived xenografts we here identified significant accumulation of SOX9-positive cells in Group 3 and Group 4 relapses. To follow relapse at the single cell level we developed an inducible dual Tet model of MYC-driven MB, where MYC was re-directed from the treatment-sensitive bulk cells to resistant, dormant SOX9-positive cells by doxycycline. In this model, distant recurrent tumors and spinal metastases developed. SOX9 promoted immune escape, DNA repair suppression and was essential for recurrence. Tumor cell dormancy was non-hierarchical, migratory and depended on MYC suppression by SOX9 to promote relapse. By using computational modeling and treatment we also showed how doxorubicin and MGMT inhibitors were specifically targeting recurrent cells that could be of potential use in future treatments for patients affected by these fatal relapses.
TMOD-31. AN ORGANOTYPIC TISSUE PLATFORM TO BRIDGE IN VITRO AND IN VIVO ASSAYS FOR BRAIN CANCER TREATMENT
Authors: Mann Breanna , Bell Noah , Dunn Denise , Floyd Scott , Hingtgen Shawn , Satterlee Andrew
Published: November 2021

Brain cancers remain one of the greatest medical challenges. The lack of experimentally tractable models that recapitulate brain structure/function represents a major impediment. Platforms that enable functional testing in high-fidelity models are urgently needed to accelerate the identification and translation of therapies to improve outcomes for patients suffering from brain cancer. In vitro assays are often too simple and artificial while in vivo studies can be time-intensive and complicated. Our live, organotypic brain slice platform can be used to seed and grow brain cancer cell lines, allowing us to bridge the existing gap in models. These tumors can rapidly establish within the brain slice microenvironment, and morphologic features of the tumor can be seen within a short period of time. The growth, migration, and treatment dynamics of tumors seen on the slices recapitulate what is observed in vivo yet is missed by in vitro models. Additionally, the brain slice platform allows for the dual seeding of different cell lines to simulate characteristics of heterogeneous tumors. Furthermore, live brain slices with embedded tumor can be generated from tumor-bearing mice. This method allows us to quantify tumor burden more effectively and allows for treatment and retreatment of the slices to understand treatment response and resistance that may occur in vivo. This brain slice platform lays the groundwork for a new clinically relevant preclinical model which provides physiologically relevant answers in a short amount of time leading to an acceleration of therapeutic translation.
CNTM-01. Evaluating Traditional and Non-Traditional Eloquent Areas in Patients with Brain Tumors: Large-scale Network Analysis Using a Machine Learning-Based Platform
Authors: Morell Alexis , Eichberg Daniel , Shah Ashish , Luther Evan , Lu Victor , Komotar Ricardo , Ivan Michael
Published: November 2021

BACKGROUND

Developing mapping tools that allow identification of traditional or non-traditional eloquent areas is necessary to minimize the risk of postoperative neurologic deficits. The objective of our study is to evaluate the use of a novel cloud-based platform that uses machine learning to identify cerebral networks in patients with brain tumors.

METHODS

We retrospectively included all adult patients who underwent surgery for brain tumor resection or thermal ablation at our Institution between the 16th of February and the 15th of May of 2021. Pre and postoperative contrast-enhanced MRI with T1-weighted and high-resolution Diffusion Tensor Imaging (DTI) sequences were uploaded into the Quicktome platform. After processing the data, we categorized the integrity of seven large-scale brain networks: sensorimotor, visual, ventral attention, central executive, default mode, dorsal attention and limbic. Affected networks were correlated with pre and postoperative clinical data, including neurologic deficits.

RESULTS

Thirty-five (35) patients were included in the study. The average age of the sample was 63.2 years, and 51.4% (n=18) were females. The most affected network was the central executive network (40%), followed by the dorsal attention and default mode networks (31.4%), while the least affected were the visual (11%) and ventral attention networks (17%). Patients with preoperative deficits showed a significantly higher number of altered networks before the surgery (p=0.021), compared to patients without deficits. In addition, we found that patients without neurologic deficits had an average of 2.06 large-scale networks affected, with 75% of them not being related to traditional eloquent areas as the sensorimotor, language or visual circuits.

CONCLUSIONS

The Quicktome platform is a practical tool that allows automatic visualization of large-scale brain networks in patients with brain tumors. Although further studies are needed, it may assist in the surgical management of traditional and non-traditional eloquent areas.
ITVT-01. 5-ALA PDT and Targeting MEK/ERK Signaling Elicits Synergistic Antitumor Effects in Diffuse Midline Glioma
Authors: Price Gabrielle , Rivera Daniel , Bouras Alexandros
Published: November 2021

Diffuse midline gliomas are highly invasive, unresectable tumors in children. To date, there is no effective treatment for DMG. Concurrent radiotherapy (RT) and systemic therapies, the standard of care, has only been successful in providing limited disease control. The major obstacle to therapy is the selectively permeable blood brain barrier (BBB) that limits systemic drug delivery. Given the unmet need for penetrant and minimally invasive DMG treatments, photodynamic therapy (PDT), with the precursor photosensitizing agent 5-aminolevulinic acid (5-ALA), is an oncologic treatment that holds promise. 5-ALA PDT of tumors occurs by targeting tumor cells that accumulate the 5-ALA metabolite, protoporphyrin IX (PPIX), with 635 nm light to create deadly reactive oxygen species (ROS). We explore the synergism of 5-ALA PDT with the MEK inhibitor, trametinib, since the RAS/MEK signaling pathway regulates tumor cell proliferation and survival and has been shown to therapeutically enhance PDT in select carcinoma models. We demonstrated that sub-micromolar levels of 5-ALA PDT and nanomolar levels of trametinib successfully decrease cell proliferation and induce apoptosis in DMG cell lines. Cell viability assays revealed that drug response differs based on the histone mutation (H3.1 or H3.3) of the line. Mechanisms of decreased cell survival involves the generation of reactive oxygen species that induces programmed cell death. Through the use of a DMG genetically engineered mouse model, we also found 5-ALA PDT to induce apoptosis in vivo. The synergistic effects of MEK inhibition and 5-ALA PDT in vitro and apoptotic effects of 5-ALA PDT in vivo, highlights the potential therapeutic efficacy of this treatment modality.
ITVT-10. Using functional Ultrasound (fUS) for real-time, depth-resolved functional and vascular delineation of brain tumors with micrometer-millisecond precision
Authors: Soloukey Sadaf , Verhoef Luuk , Mastik Frits , Generowicz Bastian , Bos Eelke , Schouten Joost , Harhangi Biswadjiet , Collée Ellen , Satoer Djaina , Smits Marion , Dirven Clemens , De Zeeuw Chris , Koekkoek Sebastiaan , Vincent Arnaud , Kruizinga Pieter
Published: November 2021

BACKGROUND

Neurosurgical practice still relies heavily on pre-operatively acquired images to guide tumor resections, a practice which comes with inherent pitfalls such as registration inaccuracy due to brain shift, and lack of real-time functional or morphological feedback. Here we describe functional Ultrasound (fUS) as a new high-resolution, depth-resolved, MRI/CT-registered imaging technique able to detect functional regions and vascular morphology during awake and anesthesized tumor resections.

MATERIALS AND METHODS

fUS relies on high-frame-rate (HFR) ultrasound, making the technique sensitive to very small motions caused by vascular dynamics (µDoppler) and allowing measurements of changes in cerebral blood volume (CBV) with micrometer-millisecond precision. This opens up the possibility to 1) detect functional response, as CBV-changes reflect changes in metabolism of activated neurons through neurovascular coupling, and 2) visualize in-vivo vascular morphology of pathological and healthy tissue with high resolution at unprecedented depths. During a range of anesthetized and awake neurosurgical procedures we acquired vascular and functional images of brain and spinal cord using conventional ultrasound probes connected to a research acquisition system. Building on Brainlab’s Intra-Operative Navigation modules, we co-registered our intra-operative Power Doppler Images (PDIs) to patient-registered MRI/CT-data in real-time.

RESULTS

During meningioma and glioma resections, our co-registered PDIs revealed fUS’ ability to visualize the tumor’s feeding vessels and vascular borders in real-time, with a level of detail unprecedented by conventional MRI-sequences. During awake resections, fUS was able to detect distinct, ESM-confirmed functional areas as activated during conventional motor and language tasks. In all cases, images were acquired with micrometer-millisecond (300 µm, 1.5–2.0 ms) precision at imaging depths exceeding 5 cm.

CONCLUSION

fUS is a new real-time, high-resolution and depth-resolved imaging technique, combining favorable imaging specifications with characteristics such as mobility and ease of use which are uniquely beneficial for a potential image-guided neurosurgical tool.
Immunotherapeutic early-phase clinical trials and malignant gliomas: A single-center experience and comprehensive immunophenotyping of circulating leukocytes
Authors: Simonelli Matteo , Persico Pasquale , Capucetti Arianna , Carenza Claudia , Franzese Sara , Lorenzi Elena , Dipasquale Angelo , Losurdo Agnese , Giordano Laura , Pessina Federico , Navarria Pierina , Politi Letterio S , Mavilio Domenico , Locati Massimo , Della Bella Silvia , Santoro Armando , Bonecchi Raffaella
Published: November 2021

Background

Immunotherapeutic early-phase clinical trials (ieCTs) increasingly adopt large expansion cohorts exploring novel agents across different tumor types. High-grade glioma (HGG) patients are usually excluded from these trials.

Methods

Data of patients with recurrent HGGs treated within multicohort ieCTs between February 2014 and August 2019 (experimental group, EG) at our Phase I Unit were retrospectively reviewed and compared to a matched control group (CG) of patients treated with standard therapies. We retrospectively evaluated clinical, laboratory, and molecular parameters through univariate and multivariate analysis. A prospective characterization of circulating leukocyte subpopulations was performed in the latest twenty patients enrolled in the EG, with a statistical significance cutoff of P < .1.

Results

Thirty HGG patients were treated into six ieCTs. Fifteen patients received monotherapies (anti-PD-1, anti-CSF-1R, anti-TGFβ, anti-cereblon), fifteen patients combination regimens (anti-PD-L1 + anti-CD38, anti-PD-1 + anti-CSF-1R). In the EG, median progression-free survival and overall survival (OS) from treatment initiation were 1.8 and 8.6 months; twelve patients survived more than 12 months, and two of them more than 6 years. Univariate analysis identified O6-methylguanine DNA methyltransferase (MGMT) promoter methylation and total protein value at six weeks as significantly correlated with a better outcome. Decreased circulating neutrophils and increased conventional dendritic cells levels lead to significantly better OS.

Conclusions

A subgroup of EG patients achieved remarkably durable disease control. MGMT promoter methylation identifies patients who benefit more from immunotherapy. Monitoring dynamic changes of innate immune cell populations may help to predict clinical outcomes.
Evaluation of Flavor Effects on Oral Nicotine Liking and/or Disliking Using the Taste Reactivity Test in Rats
Authors: Bagdas Deniz , Rupprecht Laura E , Nunes Eric J , Schillinger Emma , Immanuel Judah J , Addy Nii A
Published: November 2021

Introduction

Tobacco product flavors may change the sensory properties of nicotine, such as taste and olfactory cues, which may alter nicotine reward and aversion and nicotine taking behavior. The hedonic or aversive value of a taste stimulus can be evaluated by examining affective orofacial movements in rodents.

Aims and Methods

We characterized taste responses to various oral nicotine concentrations using the taste reactivity test in rats. We also evaluated the impact of menthol and benzaldehyde (cherry, almond) flavorants on both ingestive and aversive responses to oral nicotine. Adult Sprague-Dawley rats (n = 5–10 per sex per group) were implanted with intraoral catheters and received 20 infusions (200 µl/ea). Nicotine (1–100 µg/mL) was evaluated in taste reactivity test to determine taste responses to nicotine. Later, the effects of menthol (50 µg/mL) and benzaldehyde (100 µg/mL) on the taste responses to nicotine were determined.

Results

Nicotine at low concentrations (3 µg/mL in males, 1 µg/mL in females) elicited significantly greater ingestive responses compared with water, whereas higher nicotine concentrations (≥30 µg/mL in males, ≥10 µg/mL in females) elicited significant aversive reactions. Thus, intraoral nicotine induced both hedonic and aversive responses in a concentration- and sex-dependent manner. Females were more sensitive to nicotine’s concentration. The addition of menthol or benzaldehyde significantly increased the hedonic responses to nicotine, and significantly decreased the aversive nicotine responses.

Conclusions

Oral nicotine induces both hedonic and aversive taste responses, which may represent liking and disliking. Menthol and benzaldehyde can alter the orosensory experience of nicotine, which may influence nicotine’s abuse liability.

Implications

Our work represents a model to study impact of flavors on oral nicotine liking and disliking responses in rats. Moreover, our findings show that menthol and benzaldehyde alter the orosensory experience of nicotine, suggesting that both could influence nicotine’s abuse liability.
Antipseudomonal Versus Narrow-Spectrum Agents for the Treatment of Community-Onset Intra-abdominal Infections
Authors: Worden Lacy J , Dumkow Lisa E , VanLangen Kali M , Beuschel Thomas S , Jameson Andrew P
Published: November 2021

Background

Antipseudomonal antibiotics are often used to treat community-acquired intra-abdominal infections (CA-IAIs) despite common causative pathogens being susceptible to more narrow-spectrum agents. The purpose of this study was to compare treatment-associated complications in adult patients treated for CA-IAI with antipseudomonal versus narrow-spectrum regimens.

Methods

This retrospective cohort study included patients >18 years admitted for CA-IAI treated with antibiotics. The primary objective of this study was to compare 90-day treatment-associated complications between patients treated empirically with antipseudomonal versus narrow-spectrum regimens. Secondary objectives were to compare infection and treatment characteristics along with patient outcomes. Subgroup analyses were planned to compare outcomes of patients with low-risk and high-risk CA-IAIs and patients requiring surgical intervention versus medically managed.

Results

A total of 350 patients were included: antipseudomonal, n=204; narrow spectrum, n=146. There were no differences in 90-day treatment-associated complications between groups (antipseudomonal 15.1% vs narrow spectrum 11.3%, P=.296). In addition, no differences were observed in hospital length of stay, 90-day readmission, Clostridiodes difficile, or mortality. In multivariate logistic regression, treatment with a narrow-spectrum regimen (odds ratio [OR], 0.75; 95% confidence interval, 0.39–1.45) was not independently associated with the primary outcome. No differences were observed in 90-day treatment-associated complications for (1) patients with low-risk (antipseudomonal 15% vs narrow spectrum 9.6%, P=.154) or high-risk CA-IAI (antipseudomonal 15.8% vs narrow spectrum 22.2%, P=.588) or (2) those who were surgically (antipseudomonal 8.5% vs narrow spectrum 9.2%, P=.877) or medically managed (antipseudomonal 23.1 vs narrow spectrum 14.5, P=.178).

Conclusions

Treatment-associated complications were similar among patients treated with antipseudomonal and narrow-spectrum antibiotics. Antipseudomonal therapy is likely unnecessary for most patients with CA-IAI.
Invertibility conditions for field transformations with derivatives: Toward extensions of disformal transformation with higher derivatives
Authors: Babichev Eugeny , Izumi Keisuke , Tanahashi Norihiro , Yamaguchi Masahide
Published: November 2021

We discuss a field transformation from fields ψa to other fields ϕi that involves derivatives, $\phi _i = \bar{\phi }_i(\psi _a, \partial _\alpha \psi _a, \ldots ;x^\mu )$, and derive conditions for this transformation to be invertible, primarily focusing on the simplest case that the transformation maps between a pair of fields and involves up to their first derivatives. General field transformation of this type changes the number of degrees of freedom; hence, for the transformation to be invertible, it must satisfy certain degeneracy conditions so that additional degrees of freedom do not appear. Our derivation of necessary and sufficient conditions for invertible transformation is based on the method of characteristics, which is used to count the number of independent solutions of a given differential equation. As applications of the invertibility conditions, we show some non-trivial examples of the invertible field transformations with derivatives, and also give a rigorous proof that a simple extension of the disformal transformation involving a second derivative of the scalar field is not invertible.
pH-responsive delivery of H2 through ammonia borane-loaded mesoporous silica nanoparticles improves recovery after spinal cord injury by moderating oxidative stress and regulating microglial polarization
Authors: Liu Yi , Wang Yeying , Xiao Bing , Tang Guoke , Yu Jiangming , Wang Weiheng , Xu Guohua , Ye Xiaojian
Published: November 2021

Imbalance of oxidative and inflammatory regulation is the main contributor to neurofunctional deterioration and failure of rebuilding spared neural networks after spinal cord injury (SCI). As an emerging biosafe strategy for protecting against oxidative and inflammatory damage, hydrogen (H2) therapy is a promising approach for improving the microenvironment to allow neural regeneration. However, achieving release of H2 at sufficient concentrations specifically into the injured area is critical for the therapeutic effect of H2. Thus, we assembled SiO2@mSiO2 mesoporous silica nanoparticles and loaded them with ammonia borane (AB), which has abundant capacity and allows controllable release of H2 in an acid-dependent manner. The release of H2 from AB/SiO2@mSiO2 was satisfactory at pH 6.6, which is approximately equal to the microenvironmental acidity after SCI. After AB/SiO2@mSiO2 were intrathecally administered to rat models of SCI, continuous release of H2 from these nanoparticles synergistically enhanced neurofunctional recovery, reduced fibrotic scar formation and promoted neural regeneration by suppressing oxidative stress reaction. Furthermore, in the subacute phase of SCI, microglia were markedly polarized toward the M2 phenotype by H2 via inhibition of TLR9 expression in astrocytes. In conclusion, H2 delivery through AB/SiO2@mSiO2 has the potential to efficiently treat SCI through comprehensive modulation of the oxidative and inflammatory imbalance in the microenvironment.
Preparation of EGCG decorated, injectable extracellular vesicles for cartilage repair in rat arthritis
Authors: Song Changwei , Xu Shibo , Chang Linna , Zhao Xingjun , Mei Xifan , Ren Xiuli , Chen Zhenhua
Published: November 2021

Arthritis is a kind of chronic inflammatory autoimmune disease, which can destroy joint cartilage and bone, leading to joint pain, joint swelling, and limited mobility. Traditional therapies have many side effects or focus too much on anti-inflammation while neglecting joint repair. In this experiment, we combined Epigallocatechin gallate (EGCG) with extracellular vesicles derived from macrophages to treat rheumatoid arthritis. Sustained-release resulted in a significant decrease in chondrocyte expression of hypoxia-inducible factor 1-alpha, a decrease in apoptosis-related proteins Cytochrome C, Caspase-3, Caspase-9, and Bax. Molecular biological analysis showed that extracellular vesicles-encapsulated EGCG (EVs-EGCG) more significantly upregulated type II collagen expression by about 1.8-fold than EGCG alone, which was more beneficial for arthritis repair. Animal experiments revealed that these EGCG-coated extracellular vesicles significantly reduced swelling, decreased synovial hyperplasia, repaired cartilage, and attenuated arthritis-related pathology scores in arthritic rats. Measurement data showed that EVs-EGCG treatment reduced joint swelling by approximately 39.5% in rheumatoid rats. In vitro studies have shown that this EVs-EGCG can increase the expression of cartilage type II collagen and reduce apoptosis of chondrocytes. Moreover, it was demonstrated in vivo experiments to reduce cartilage destruction in rheumatoid arthritis rats, providing a solution for the treatment of rheumatoid arthritis.
Purinergic signalling in systemic sclerosis
Authors: Höppner Jakob , Bruni Cosimo , Distler Oliver , Robson Simon C , Burmester Gerd R , Siegert Elise , Distler Jörg H W
Published: November 2021

SSc is a chronic autoimmune rheumatic disease that involves numerous organs and presents major management challenges. The histopathologic hallmarks of SSc include vasculopathy, fibrosis and autoimmune phenomena involving both innate and adaptive immune systems. Purinergic signalling is a pathway that may be implicated in the pathophysiology of several of these disease manifestations. Extracellular purines are potent signalling mediators, which have been shown to be dysregulated in SSc. As examples, purines can exacerbate vasculopathy and provoke platelet dysfunction; as well as contributing to immune dysregulation. Elements of purinergic signalling further promote organ and tissue fibrosis in several disease models. Here, we provide an overview of extracellular purine metabolism in purinergic signalling and link disorders of these to the molecular pathology of SSc. We also discuss targeting the purinergic signalling and explore the translational applications for new therapeutic options in SSc.