bluuebunny/crossref_metadata_2025 huggingface dataset:
TMIC-42. LOCAL TISSUE METABOLOMICS BASED BIOMARKERS OF RESPONSE TO THERAPY FOR GLIOBLASTOMA
Authors: Rajani Karishma , Carlstrom Lucas , Jacobs Joshua , Schroeder Mark , Olson Ian , Wang Xuewei , Sarkaria Jann , Burns Terry
Published: November 2019

Glioblastoma (GBM) is a common deadly malignant brain cancer of the central nervous system (CNS), with a median survival of 12–15 months. Scientific advancements are lacking in developing effective therapies for both primary GBM, as well as secondary GBMs, that typically originate as malignant transformation of lower-grade isocitrate dehydrogenase (IDH) 1-mutant tumors. The unique metabolomic profile of IDH1-mutant tumors may present opportunities to develop biomarker signatures of therapeutic efficacy. Microdialysis is an extracellular fluid sampling collection technique utilizing a perfused semipermeable catheter to permit diffusion of molecules between brain interstitium and the perfusate. We hypothesized that microdialysis may identify a metabolomics-based biomarker response to therapy in IDH1-mutant tumors. To test this hypothesis, orthotopic xenografts were generated from two patient-derived GBM lines harboring mutations in IDH1. Perfusates were collected from intra-cranial tumors in aythmic nude mice sampled at baseline and 72h post treatment with temozolomide, an oral alkylating agent used to treat IDH1-mutant gliomas, compared with vehicle treatment, and TMZ-treated non-tumor bearing animals. Perfusates were analyzed via unsupervised metabolomic profiling using both gas and liquid chromatography-mass spectrometry (GC/LC-MS). Tumor specific metabolites such as carnitine and pyruvic acid were detected in microdialysate from tumor bearing mice compared to non-tumor bearing mice. Microdialysis is a feasible technology to identify metabolomics-based biomarker in IDH1-mutant PDX. This work is complemented by parallel analysis of non-IDH1-mutant and TMZ resistant xenografts to yield predictive in vivo tissue biomarkers of drug responsiveness translatable to clinical practice.
TMIC-43. ROLE OF EXTRACELLULAR FERRITIN HEAVY CHAIN PROTEIN IN GLIOBLASTOMA MULTIFORME
Authors: Pandya Bhavyata , Ravi Vagisha , Connor James
Published: November 2019

Increased expression of Ferritin heavy chain (FHC) protein has been associated with poor prognosis in Glioblastoma Multiforme (GBM) which is one of the most aggressive and common types of brain cancer. GBM patients have also been found to have increased extracellular ferritin levels, in their serum and cerebrospinal fluid (CSF), which are lowered once the source/tumor has been resected. Extracellular FHC can function as an iron delivery protein, and increasing amount of iron has been known to contribute to tumor initiation and proliferation. To study the effect of extracellular FHC in GBM cells we used patient derived GBM, CD133+ cancer stem cells (GSCs) from the pro-neural (T3691) and mesenchymal (T387) subtypes. Using recombinant FHC, conjugated with quantum dots (QD), we observed significant increase in cellular viability and intracellular uptake of FHC by the GSCs in a dose dependent manner. Our lab has previously shown that extracellular FHC interacts with T-Cell Immunoglobulin Mucin Receptor 1 (Tim-1) in the human oligodendrocytes. In order to determine if GSCs express the Tim-1 receptor we first confirmed its expression on GSCs using immunoblotting and immunocytochemistry. To test if FHC interacts with Tim-1, we performed knockdown of Tim-1 using siRNAs. However, the siRNA was not able to downregulate the Tim-1 receptors. Next, we exposed the GSCs to Sema4A, which has been shown in our previous studies to interact with Tim-1 receptor on human oligodendrocytes and is toxic to oligodendrocytes. The GSCs however were not affected by the saturable concentration of Sema4A. Thus, through this study we have shown the expression of potential FHC receptors on GSCs and a robust effect of H-ferritin on GSCs proliferation. Further experiments are warranted in this direction to understand this extracellular FHC uptake pathway and its role in GBM cell proliferation.
TMIC-44. IL-1 ANTAGONIST ANAKINRA INHIBITS GLIOBLASTOMA PROLIFERATION BY ANTAGONIZING THE PROINFLAMMATORY MICROENVIRONMENT
Authors: Effinger David , Hübner Max , Wu Tingting , Thon Niklas , Kreth Friedrich-Wilhelm , Kreth Simone
Published: November 2019

INTRODUCTION

The recombinant IL-1 receptor antagonist anakinra prevents binding of IL-1 to its receptor and blocks IL-1β-mediated proinflammatory signaling. It is currently used in the treatment of autoinflammatory diseases. As inflammation is a major driver of malignancy, we hypothesized that anakinra – by ameliorating the inflammatory tumor environment – might be capable to mitigate glioblastoma (GBM) progression.

METHODS

T98G GBM cells were cultivated with PBMC, separated by cell culture inserts with or without anakinra and incubated 48h in 5% O2 mimicking the GBM microenvironment. T-cells were obtained by magnetic bead isolation. mRNA expression levels were measured by quantitative Real-Time-PCR (qRT-PCR). Cytokine production was assessed by ELISA. Cell proliferation was analyzed by flow cytometric quantification of Ki-67 protein expression. Anakinra has been provided by Swedish Orphan Biovitrum AB (Sweden). Results are presented as mean±SEM, p-Values were calculated using Student’s t-test.

RESULTS

After administration of anakinra, mRNA expression levels of the inflammatory and proangiogenic genes IL-1β, COX-2, CCL2 and IL-8 were reduced in T98G (-64%±19.1%, -56.2%±21.3%, -87.1%±28.8%, -91.7%±27.2%, n=7, p< 0.05). Surprisingly, no changes of these targets were detectable in PBMC. However, in T-cells, anakinra induced mRNA expression of Th2 transcription factor GATA3 and the antiinflammatory cytokines IL-4 and IL-10 (+6,7%±4,6%, +36,1%±22,9%, +69,1%32,8%, n=10, p< 0.05). The expression of the protumorigenic genes IL-22, IL-17 as well as IFNγ was dramatically repressed (-63.2%±21.9%, -88.1%±21.7%, -85.6%±45.2%, n=10, p< 0.05), protein secretion of IL-22 and IFNγ was strongly blocked (-36.3%±9.1%, -13.9%±0.5%, n=6, p< 0.05). Importantly, treatment with anakinra markedly attenuated GBM cell proliferation (-20.1%±5%, n=4, p< 0.05).

CONCLUSION

Anakinra indeed puts the brake on proinflammatory signaling pathways in GBM cells and simultaneously promotes a shift towards an anti-inflammatory T-cell phenotype. As a result, GBM proliferation is diminished. Hence, administration of anakinra might be an interesting and novel therapeutic approach to reduce Glioblastoma aggressiveness.
TMIC-48. MACROPHAGE DEPLETION COMBINED WITH RADIATION IN A PRECLINICAL MEDULLOBLASTOMA MODEL
Authors: Crotty Erin , Brasel Ken , Pakiam Fiona , Girard Emily , Olson James
Published: November 2019

BACKGROUND

Radiation induces a measurable immune response, yet this anti-tumor immunity is often suboptimal at eliminating residual brain tumor cells. Medulloblastomas, along with other pediatric brain tumors, tend to recur in the primary resection bed following irradiation. Infiltrating macrophage within the tumor (TAM) are radioresistant immune cells that may limit the effectiveness of radiotherapy and promote tumor regrowth through their immunosuppressive and pro-tumorigenic functions. Therefore, we explored whether CSF-1 receptor (CSF1R) inhibition, and essentially TAM depletion, could augment radiation and/or reduce local recurrence.

METHODS

Selected CSF1R inhibitors were tested on both human and mouse macrophage in vitro. In vivo studies were performed on a patient-derived orthotopic xenograft (PDOX) model of Group 3 medulloblastoma, Med411-FH. Macrophage depletion was achieved using the anti-murine CSF1R antibody, AFS98, injected intra-peritoneally 10 days prior to, concurrently, and after radiation.

RESULTS

CSF1R antibodies and small molecule tyrosine kinase inhibitors were effective at stanching macrophage survival in culture. In a PDOX medulloblastoma model, both classes of CSF1R inhibitors were effective at reducing macrophage in the brain after approximately 10 days of administration, with maximal effect of 90% depletion achieved after 21 days. In a combinatorial study of AFS98 and irradiation, TAM depletion conferred a very modest effect on tumor growth (p=0.003) and had no effect on overall survival when combined with radiation (p=0.86). Interestingly, we did observe a trend toward reduction in metastatic spinal disease following radiation in the AFS98-treated cohort.

CONCLUSION

CSF1R antibody administration effectively eliminated macrophage and microglia in the brain and spine, suggesting adequate blood-brain barrier penetration in our xenograft model. While CSF1R inhibition combined with radiation was ineffective at prolonging survival, further studies are needed to investigate a modest effect on brain tumor growth and an observed (yet not statistically significant) difference in metastatic spinal recurrence in drug-treated animals.
TMIC-51. GBP1 RECRUITS MACROPHAGES TO PROMOTE GLIOBLASTOMA GROWTH
Authors: Chen Lili , Li Ming
Published: November 2019

Guanylate binding protein 1 (GBP1) is an interferon-inducible large GTPase which plays a key role in tumor development, but the molecular mechanism is poorly understood. Here we investigated whether GBP1 could influence the tumor microenvironment in glioblastoma, the most common and malignant brain tumor. We found that forced expression of GBP1 in glioblastoma cells induced macrophage polarization toward an M2 phenotype via upregulating Chemokine (C-C motif) ligand 2 (CCL2). CCL2 acted via its receptor C-C chemokine receptor 2 (CCR2) to enhance macrophage cell migration in vitro. The M2 macrophages in turn promoted glioblastoma cell proliferation and migration. The orthotopic mouse model showed that GBP1 recruited M2 macrophages into tumor to promote glioblastoma progression, and targeting CCL2/CCR2 signaling axis with a small molecule inhibitor RS504393 led to decreased macrophage attraction and M2 polarization and a significant tumor growth retardation and prolonged survival of tumor-bearing mice. Clinically, GBP1 expression positively correlated with M2 macrophage numbers and CCL2 expression in glioblastoma. Taken together, our results reveal that GBP1 modulates the tumor immune microenvironment through CCL2 induction to promote glioblastoma infiltrating growth, and targeting tumor-associated macrophages may represent a new therapeutic strategy against glioblastoma.
TMIC-53. IMPACT OF HFE EXPRESSION AND SEX ON THE TUMOR IMMUNE MICROENVIRONMENT IN GLIOBLASTOMA
Authors: Nesterova Darya , Lee Sang , Zacharia Brad , Lathia Justin , Rubin Joshua , Berens Michael , Barnholtz-Sloan Jill , Connor James
Published: November 2019

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Despite aggressive treatment, the median survival for patients with GBM remains approximately 1 year. Recent evidence demonstrates GBM is a sexually dimorphic disease, and that females have greater overall survival. We previously showed expression levels of HFE, an iron-regulating gene, significantly impacts survival in GBM. Moreover, this effect is sex-specific: females with low HFE expressing tumors have significantly longer survival than males with similar HFE expression. Moreover, HFE expression and survival appeared to correlate with markers of immune activity within the tumors. To further explore the impact of HFE expression on the immune infiltration of GBM, we utilized available TCGA GBM data for analysis by EstimateMe and DeconvuluteMe. These platforms utilize expression data to estimate the magnitude and cellular composition of immune cell infiltrates in tumors, respectively. We sought to correlate these computational measures with HFE expression levels and survival. We confirmed that immune and stromal cell infiltration of tumors is negatively correlated to survival. Consistent with our findings that high HFE levels have a negative impact on survival, high HFE expressing tumors possessed higher levels of both immune and stromal cell infiltration. Additionally, sex of the patient, but not MGMT methylation status, was significantly correlated with immune and stromal infiltration, with males displaying higher levels of infiltration. High HFE tumors were composed of greater numbers of all immune cell types than low HFE tumors. In both HFE groups, monocytes and macrophages comprised the greatest fraction of cells. At low HFE and positive MGMT methylation (where we previously noted the greatest survival differences), we find females have lower monocyte and M2 macrophage markers compared to males with similar features. Collectively, these data suggest that an HFE-immune cell infiltrate axis contributes to sex differences in GBM survival.
TMOD-03. SOMATIC MUTATIONS OF CHROMATIN REGULATOR Kmt2d IN CEREBELLAR PRECURSORS INFLUENCES SHH-MEDULLOBLASTOMA TUMORIGENESIS
Authors: Sanghrajka Reeti , Tan I-li , Wojcinski Alexandre , Rallapalli Harikrishna , Turnbull Daniel , Ge Kai , Joyner Alexandra
Published: November 2019

Medulloblastoma (MB), the most common malignant pediatric brain tumor, is a classic example of dysregulation of developmental pathways leading to tumorogenesis. Despite advancements in multi-modal therapies, most patients suffer from long-term neurocognitive and neuroendocrine disabilities. The Sonic Hedgehog subgroup of MB (SHH-MB) accounts for ~30% of all cases and originates from ATOH1+ cerebellar granule cell precursors (GCPs). Experimental data in mice has shown that activating mutations in the SHH pathway induce tumors only in rare GCPs, suggesting that additional mutations and epigenetic changes are required to influence tumor progression. The KMT2D gene, encoding the histone-lysine N-methyltransferase 2D, is amongst the ten most frequently mutated genes in MB, with somatic mutations seen in ~15% of all SHH-MB patients. We developed sporadic mouse models of SHH-MB with a low penetrance to enable studies of secondary mutations (Tan, PNAS, 2018). Immunofluorescence staining for KMT2D on early-stage SHH-MB lesions, mid-stage and late-stage tumors revealed that a subset of lesions/tumors (16/98) do not express KMT2D and are negative for H3K4me3. Interestingly, P53 and KMT2D expression showed a positive correlation in ~94% of tumors/lesions and NeuN and KMT2D showed a positive correlation in ~92% of tumors/lesions. In order to determine the roles for KMT2D in GCP proliferation and differentiation, and uncover whether and how KMT2D promotes SHH-MB tumorigenesis, we are using genetic mouse-models whereby Kmt2d is heterozygously or homozygously deleted alone, or in conjunction with activation of the SHH pathway. Mice with SHH-MB tumors expressing SmoM2 and a loss of Kmt2d develop aggressive tumors at high penetrance, with metastatic leptomeningeal spread in the brain stem and spinal cord. Thus, loss of Kmt2d increases SHH-MB tumor progression and leads to malignancy. Ongoing studies are determining how the chromatin landscape and gene expression are changed when Kmt2d is deleted in GCPs.
ACTR-70. A MULTISITE CLINICAL TRIAL OF SPECTROSCOPIC MRI-GUIDED RADIATION DOSE ESCALATION IN GLIOBLASTOMA PATIENTS
Authors: Mellon Eric , Gurbani Saumya , Ramesh Karthik , Weinberg Brent , Kleinberg Lawrence , Schreibmann Eduard , Barker Peter , Maudsley Andrew , Shim Hyunsuk , Shu Hui-Kuo
Published: November 2019

The standard of care for glioblastoma is neurosurgical resection followed by radiation therapy (RT) and temozolomide (TMZ) chemotherapy. Although RT is effective for glioblastoma, attempts to improve survival using RT dose escalation above 60 Gy have been largely unsuccessful. This may be because prior attempts have been targeted to resection cavity or enhancing tumor, which may not accurately predict areas at highest recurrence risk. To overcome the limitations of standard T1 and T2-weighted MRI in predicting tumor recurrence, we have shown that supplementation with 3D high-resolution spectroscopic MRI (sMRI) identifies actively proliferating tumor beyond areas of T1-enhancement by measuring endogenous metabolites and their ratios. Previously, we demonstrated that the choline to N-acetylaspartate ratio (Cho/NAA) best correlates with tumor cellularity in surgically resected tissue (ρ=0.82, p< 0.001) and, most importantly, areas of sMRI metabolic abnormalities predate disease recurrence in those same areas (Cordova et al, Neuro-Oncology 2016). Therefore, we seek to identify whether sMRI can be used by radiation oncologists to choose the optimal regions to target for RT dose escalation. To assess its feasibility and safety, we developed a web-based imaging platform designed specifically to incorporate sMRI into the RT planning clinical workflow and are using it in a multisite sMRI-guided dose escalation trial (NCT03137888; Emory, Johns Hopkins, U. Miami). Recently, we have completed full enrollment including 30 patients treated with sMRI-guided dose escalated RT across three institutions. We have demonstrated successful integration of sMRI into the RT planning workflow, and we have delivered sMRI-guided dose escalated RT plans to glioblastoma patients without severe adverse events to date. Follow-up data will be analyzed for overall and progression-free survival. Based on the feasibility and safety of this technique in the current trial, we plan to assess the efficacy of sMRI-guided dose-escalated RT on patient outcomes in a NCTN clinical trial.
TMOD-11. CHARACTERISATION OF THE POST-SURGICAL INVASIVE TUMOUR NICHE USING ASTROCYTE-GLIOBLASTOMA ORGANOIDS AND DECELLULARISED HUMAN BRAIN
Authors: Diksin Mohammed , Rowlinson Jonathan , Kondrashov Alexander , Denning Chris , Hughes Jaime , Constantin-Teodosiu Tim , Cui Wei , Scurr David , Ahmad Omar , Gell Christopher , Onion David , Croxall Nicola , Smith Stuart , Rahman Ruman
Published: November 2019

Glioblastoma therapeutic challenges are in considerable part due to myriad survival mechanisms which allow malignant cells to repurpose signalling pathways within discreet microenvironments. These Darwinian adaptations facilitate invasion into brain parenchyma and perivascular space. We hypothesised that pre-clinical modelling of glioma invasion by recapitulating early events occurring immediately after surgery at the glioblastoma invasive margin, could reveal the cross-talk between malignant cells and surrounding healthy astrocytes. We first generated transgenic H1-derived neural stem cells using CRISPR/Cas9-mediated knock-in of the YFP reporter gene under the control of the GFAP promoter at the AAVS1 safe harbour locus. Reproducible ultrahigh-throughput AggreWells™ (7200 mini-wells per plate) were used to create astrocyte-glioblastoma organoids, which we term ‘Gliomasphere Matrices’. YFP-labelled astrocytes were co-cultured with 10 treatment-naïve patient-derived cell lines isolated from the 5-aminolevulinic (5ALA)-determined glioblastoma invasive margin. Co-cultures were seeded upon a sequentially constructed, time-of-flight secondary ion mass spectrometry (ToF-SIMS)-characterised decellularised human brain extract. YFP-astrocytes were purified from each of the 10 Gliomasphere Matrices using fluorescence-activated cell sorting (FACS) after 6- and 10-days co-culture. RNA-sequencing of the putatively reprogrammed YFP-astrocytes showed the characteristic expression of canonical key regulators of multiple malignant diseases including high-grade glioma such as SND1 and EFNB2 in addition to the identification of a single novel marker located at chromosome 1 (C1orf61), highly expressed in malignant glioma when compared to somatic cancers according to TCGA RNA-sequencing data. Differentiated YFP-astrocytes also overexpressed IFITM2 and IFITM10, known to be involved in priming resistance against pathogenic microorganisms. This ultimately suggests a fluctuating state between malignant transformation imposed by the highly infiltrative glioma cells and the counter-action of the normal astrocytes to these deleterious invasive cells. This multi-faceted model offers a unique opportunity to recapitulate early molecular cross-talk which facilitates glioblastoma recurrence and may be utilised for high-throughput drug screening.
TMOD-35. PREDICTION OF OVERALL SURVIVAL, AND MOLECULAR MARKERS IN GLIOMAS VIA ANALYSIS OF DIGITAL PATHOLOGY IMAGES USING DEEP LEARNING
Authors: Rathore Saima , Iftikhar Muhammad , Nasrallah MacLean , Gurcan Metin , Rajpoot Nasir , Mourelatos Zissimos
Published: November 2019

BACKGROUND

Microscopic features of brain tumors, such as tumor cell morphology, type/degree of microvascular hyperplasia, mitotic activity, and extent of zonal/geographic necrosis, among many others, are measurable and reflect underlying molecular markers that are predictive of patient prognosis, signifying that quantitative analysis may provide insight into disease mechanics. We developed a computational method to predict overall-survival and molecular markers for brain tumors using deep learning on whole-slide digital images (WSDI).

METHODS

The WSDI were acquired from TCGA for 663 patients [IDH:333 wildtype, 330 mutants, 1p/19q:201 non-codeleted, 129 codeleted]. A set of 100 region-of-interest each comprising 1024x1024 that contained viable tumor with descriptive histologic characteristics and that were free of artifacts were extracted. A modified version of ResNet with architecture of 50 convolutional layers was used. The network was optimized using stochastic gradient decent optimization method with binary cross-entropy loss. Sigmoid- and linear-activation were, respectively, used as final layer for mutation and survival prediction. Data was divided into training (50%), testing (25%), and validation (25%).

RESULTS

The model predicted IDH and 1p/19q with an accuracy of 88.92%[sensitivity(se)/ specificity(sp)=87.77/84.35] and 88.23%(se/sp=87.38/88.58), respectively. The accuracy was further improved, when classification was done within homogeneous grades, for IDH [II=90.50%(se/sp=91.52/78.57), III=91.21%(se/sp=91.89/89.47), IV=92.77%(se/sp=77.78/93.51)] and 1p/19q [II=91.51%(se/sp=91.30/91.66), III=92.56(se/sp =93.33,92.04)]. The Pearson correlation coefficient between the predicted scores and overall-survival was 0.79 (p< 0.0001).

CONCLUSION

Our findings suggest that deep learning techniques can be applied to WSDI for objective, and accurate prediction of mutations and survival. Our approach, when compared with expensive molecular based assays that invariably capture molecular markers from a small part of the tumor and also destroy the tissue, could (i) offer the same service at a reduced price, (ii) enable disease characterization across the entire landscape of the tissue, (iii) be beneficial for tissues inadequate for molecular testing, and (iv) does not need physical shipping of the tissue.
SCIDOT-01. NANOPARTICLE DELIVERY OF MIRNAS TO INHIBIT GBM STEM CELLS
Authors: Lopez Hernando
Published: November 2019

Options for treating high-grade brain tumors remain limited. Recent developments in nanomedicine provide new and exciting opportunities to treat and manage brain tumors. Epigenetic modifications, involving deregulation of non-coding RNAs, in particular miRNAs, are emerging as critical determinants of gene expression and essential drivers of neoplastic phenotypes. Cationic polymers are a class of biomaterials with great promise for targeted molecular therapeutics. We combined this cutting-edge technology with our newly discovered stem cell inhibiting miRNAs to develop nano/miR to treat gliomas. We show these nano/miR distribute throughout an established tumor in vivo, and more importantly, delivering these tumor-suppressing miRNAs using PBAE polymers inhibits the growth of established GBM tumor in mouse models. Our findings demonstrate that identifying and validating stem cell-inhibitory in combination with current advances in nanomedicine will undoubtedly impact the development of novel therapies for targeting the CSC population and treating GBM.
SCIDOT-03. HYPERLOADED POLY(2-OXAZOLINE) MICELLES AS PERSONALIZED DRUG CARRIERS FOR BRAIN TUMORS
Authors: Hwang Duhyeong , Dismuke Taylor , Rosen Elias , Kagel John , Lim Chaemin , Zamboni William , Kabanov Alexander , Gershon Timothy , Sokolsky-Papkov Marina
Published: November 2019

Systemic therapies for brain tumors are complicated by dose-limiting extraneural toxicity, serum protein binding and restricted blood-brain barrier (BBB) permeability. For patients with SHH-subgroup medulloblastoma, SHH-pathway inhibition may be more effective and less toxic than current non-targeted therapy. However, vismodegib, which effectively targets SHH-driven basal cell carcinoma, has limited benefit for patients with SHH-driven medulloblastoma. Formulating vismodegib in poly(2-oxazoline) micelles (POx-vismo) improved delivery and efficacy, using medulloblastoma-prone hGFAP-Cre/SmoM2 (G-Smo) mice for a preclinical model. Compared to conventional vismodegib (c-vismo), POx-vismo increased maximum tolerated dose (MTD), tumor:serum ratio and penetration to brain and tumor. Further studies have shown the ability of POx micelles to load CDK4/6 inhibitor. Loading into POx micelles improved MTD and efficacy of palbociclib. Taken together, our results show the potential for poly(2-oxazoline) micelles delivery to make failed brain tumor treatments newly effective. This work was supported by the NCI Alliance for Nanotechnology in Cancer (U54CA198999, Carolina Center of Cancer Nanotechnology Excellence), by NINDS (R01NS088219, R01NS102627) and by the St. Baldrick’s Foundation. References: 1 H. Bader et al. Angew. Macromol. Chem. 1984, 123/124:457; A. Kabanov et al. FEBS Lett. 1989, 258:343; M. Yokoyama et al. Cancer Res. 1990, 50:1693. 2 M. Yokoyama et al. J. Exp. Clin. Med. 2011, 3:8. 3 T. Lorson et al. Biomaterials. 2018, 178:204. 4 R. Luxenhofer et al. Biomaterials 2010, 31:4972; A. Schulz et al. ACS Nano 2014, 8 (3):2686; Z. He et al. Biomaterials 2016, 101:296
SCIDOT-16. T2-WEIGHTED IMAGING MAY BE INDICATIVE OF DRUG DISTRIBUTION IN GLIOBLASTOMA PATIENTS
Authors: Jackson Pamela , Kim Minjee , Hawkins-Daarud Andrea , Singleton Kyle , Mohammad Afroz , Burns Terence , Parney Ian , Hu Leland , Kaufmann Timothy , Elmquist William , Sarkaria Jann , Swanson Kristin
Published: November 2019

OBJECTIVES

Dogma suggests that for brain tumors, regions of enhancement on T1-weighted gadolinium contrast enhanced (T1Gd) magnetic resonance imaging (MRI) correlate with intravenously delivered drug distribution as enhancement indicates a compromised blood-brain barrier (BBB). However, poor response to intravenous therapies highlights the importance of the diffuse disease beyond enhancing regions. This study investigated whether imaging features can provide an accurate prediction of drug distribution.

METHODS

Eight brain tumor patients (7 gliomas and 1 metastatic adenocarcinoma) were included in this Phase 0 trial. Presurgery T1-weighted, T1Gd, T2-weighted gadolinium contrast enhanced (T2Gd), and T2-weighted Fluid Attenuated Inversion Recovery (T2FLAIR) MRIs were acquired. All images underwent bias correction using the N4 algorithm, standardization of intensities, and registration. Prior to incision, patients received both an antibiotic cefazolin (6% BBB penetrance) and levetiracetam (80% BBB penetrance), an anti-seizure drug. Subsequently, multiple blood samples and image-guided biopsies were taken and analyzed for drug concentration using liquid chromatography mass spectrometry. Biopsy drug levels are reported as Brain-Plasma Ratio (BPR), the ratio of biopsy concentration relative to plasma concentration. Mean image intensity was extracted from an 8x8 mm window surrounding each biopsy location. Regression analysis was performed to determine which combination of image types were linearly predictive of BPR for both drugs. Correlations were also analyzed according to the biopsy location radiographic appearance.

RESULTS

Regression analysis revealed that T2Gd intensity was linearly predictive of cefazolin BPR and FLAIR intensity was linearly predictive of levetiracetam BPR (p=0.009 and 0.041, respectively). Grouping samples according the the radiographic appearance revealed that levetiracetam BPR had a similar pattern of values to that of FLAIR intensities and cefazolin BPR had a similar pattern to T2, further supporting the regression analysis results.

CONCLUSIONS

Local concentrations of drug may be related to T2-weighted signals (T2Gd and T2FLAIR) rather than the gadolinium distribution on T1Gd images.
SCIDOT-24. INCREASING INDUCED NEURAL STEM CELL PERSISTENCE IN THE TUMOR RESECTION CAVITY
Authors: Bomba Hunter , Sheets Kevin , Carey-Ewend Abigail , Goetz Morgan , Bago Juli , Khagi Simon , Hingtgen Shawn
Published: November 2019

Glioblastoma multiforme (GBM) is the most common primary brain cancer in adults. Afflicted patients have a median survival rate of only 15 months, and patient survival statistics have remained stagnant for over three decades. Current standard of care includes maximal safe tumor resection, chemotherapy, and radiation. Nevertheless, GBM is aggressive, making recurrence and deeper tumor infiltration inevitable. Neural stem cells transdifferentiated from a skin biopsy, i.e. induced neural stem cells (iNSCs), have the innate ability to home to tumors, and, when engineered with cytotoxic proteins, can actively kill cancer cells. However, direct injection of these cells into the hostile immune environment of the tumor resection cavity results in an accelerated clearance rate and therefore a shortened therapeutic window. To combat this clearance issue, we investigated the FDA-approved hemostatic matrix, Floseal, as a cell delivery platform to increase iNSC persistence. In vitro, SEM imaging showed homogeneous iNSC distribution throughout Floseal. Using our surgical resection model of GBM in mice, we delivered iNSCs into the post-surgical cavity in Floseal and by direct injection to model current clinical delivery strategies. Serial kinetic imaging showed that human iNSC persistence delivered into the cavity in Floseal persisted over 90 days, while cells directly injected into the brain parenchyma persist less than 20 days. When we investigated the impact on tumor kill, we found the increase in persistence increased survival of GBM-bearing mice more than 30 days compared to control cells. Light-sheet microscopy showed wild-type neural stem cells migrate into invasive GBM-8 tumors in the contralateral hemisphere, and we are now using this approach to validate the homing of iNSCs delivered via Floseal. Administration of iNSCs encapsulated in the biocompatible Floseal matrix offers a promising, clinically-translatable therapeutic strategy for GBM.
SCIDOT-30. GLITIPNI: A PHASE 1B CLINICAL TRIAL COMBINING SURGICAL RESECTION WITH DIRECT INTRACEREBRAL INJECTION OF IMMUNE CHECKPOINT INHIBITORS IN PATIENTS WITH RECURRENT GLIOBLASTOMA
Authors: Duerinck Johnny , Awada Gil , Katharina Schwarze Julia , Dufait Ines , Peeters Stephanie , Seynaeve Laura , Van Binst Anne-Marie , Everaert Hendrik , Michotte Alex , Rogiers Anne , Van Velthoven Vera , Neyns Bart
Published: November 2019

INTRODUCTION

Intravenous (iv) administration of PD-1 blocking mAb is largely ineffective for the treatment of recurrent glioblastoma (rGB). Combination of iv-ipilimumab (IPI) plus nivolumab (NIVO) is associated with a high incidence of irAE. Intracerebral (ic) administration of immune-checkpoint inhibiting mAb following the resection of rGB could be a more effective and safer alternative to iv-dosing.

METHODS

Patients underwent maximal safe resection of their rGB followed by ic-injection of 10mg IPI (cohort-1) or 5mg IPI plus 10mg NIVO (cohort-2) in the wall of the resection cavity. In both cohorts 10mg nivolumab was administered iv for a max of 6 doses, starting 1 day pre-operatively.

RESULTS

21 pts were included (3 in C-1, 18 in C-2; 8F/13M; median age 56y [range 38–72]; 17 de novo GB, 4 secGB). All patients underwent maximal safe surgical resection followed by ic-injection of IPI and NIVO as planned. Median number of iv-administrations of NIVO was 5 (range 1–8). Treatment was generally well tolerated. Postoperatively, 2 patients experienced a G3 symptomatic increase in perilesional cerebral edema with neurological deterioration, reversible upon steroid treatment. One patient had worsening neurological symptoms related to an inflammatory intracerebral cyst at the resection site, requiring surgical decompression 4 months post-study treatment. Most frequent AEs were fatigue (2pts G3, 8pts G2), postoperative fever (11pts G1) and headache (3pts G2); 1pt developed G3 pneumonitis. No other immune-related AEs or treatment-related deaths occurred. After median follow-up of 60 weeks, median PFS is 14.4 weeks (95% CI 11.2–17.6); 11/21 patients are alive, and 1- and 2y-OS% are respectively 46% (95% CI 19- 73%), and15% (95% CI 0–42%).

CONCLUSION

This is the first study demonstrating the safety and activity of combined surgical resection of rGB with local intracerebral administration of immune checkpoint-inhibiting mAb. Survival compares favorably to historical controls justifying further investigation of this experimental therapy.
SCIDOT-46. MicroRNA NANOCELL THERAPY FOR GLIOBLASTOMA
Authors: Babar Khan Muhammad , Ruggieri Rosamaria , Tran Nhan , Sarkaria Jann , MacDiarmid Jennifer , Brahmbhatt Himanshu , Boockvar John , Symons Marc
Published: November 2019

Therapeutic resistance stemming from inter and intra-tumoral heterogeneity is a significant impediment towards development of effective therapeutics for glioblastoma. We hypothesized that microRNAs can potentially counteract resistance emanating from such heterogeneity as they simultaneously modulate the expression of multiple proteins. We identified microRNA-34a as a unique microRNA which modulates multiple oncoproteins in GBM using two different in silico approaches. We investigated the therapeutic effects of microRNA-34a in three primary patient-derived xenografts (PDX) representing classical (GBM6), proneural (GBM118) and mesenchymal (GBM118) subtypes; four established cell lines (T98G, U251, A172, LN229) and two cell lines with acquired resistance to temozolomide (A172-TR, LN229-TR) in vitro. Glioblastoma cell cultures showed variable responses to temozolomide but microRNA-34a inhibited proliferation in all cell cultures. Furthermore, microRNA-34a also sensitized all tested cell lines to temozolomide (combination index < 0.8, p=.03) and radiation treatment (dose enhancement factor 1.7–2.2, p=0.02). Mechanistically, microRNA 34a down-regulates at least six distinct therapeutic resistance proteins. Importantly, these resistance proteins are expressed in distinct spatial niches and are prognostic for patient survival based on our analysis of the cancer genome atlas (TCGA) data. For in vivo delivery of microRNA-34a, we utilized nanocells which are derived from genetically modified bacteria, loaded with microRNA-34a and tagged with a bispecific antibody targeting EGFR. Nanocells were injected intravenously while temozolomide was administered by oral gavage in an orthotopic PDX model. We confirmed delivery of microRNA-34a to tumor by observing down-regulation of cMet and phosphorylated Akt in treated mice. Importantly, microRNA-34a nanocells resulted in significant reduction in tumor growth (p=0.021), increased survival (p<0.001) with microRNA-34a monotherapy and synergy in combination with temozolomide in vivo. Taken together, our results suggest that delivery of miR-34a may be a powerful new adjuvant for the treatment of glioblastoma in combination with temozolomide that can mitigate both inter- and intra-tumor heterogeneity.
SCIDOT-51. OVERPOWERING MULTIPLE INHIBITORY IMMUNE CHECKPOINTS WITH A SINGLE PEPTIDE INHIBITOR ENHANCED SURVIVAL IN A SPONTANEOUS HIGH-GRADE GLIOMA CANINE PILOT-TRIAL
Authors: Olin Michael , Moertel Christopher , Elisabeth Pluhar G
Published: November 2019

Given the modest effects current immune checkpoint-inhibitors have on patients with CNS tumors, we focused our studies on the novel CD200 immune checkpoint. The CD200 checkpoint suppresses the immune system through binding of the inhibitory CD200 protein to the inhibitory receptor (CD200R1) expressed on immune cells. In addition to CD200R1, the CD200 checkpoint includes activation receptors (CD200AR), which we are targeting with a peptide ligand (CD200AR-L) to reverse the inhibitory effects of the CD200 protein. We showed that spontaneous high-grade glioma dogs receiving a canine specific CD200AR-L in combination with autologous tumor lysate vaccine had an increased median overall survival of 9 months, compared to 6.3 months with lysate alone, resulting in an overall 36-month survival of 21%. However, we have a 45% event-free (progression-free) group of dogs that died of non-tumor related deaths with an extended median survival of 18 months. Six dogs remain on trial, 87% of the dogs receiving tumor lysate only died of tumor recurrence within 6 months. Serum chemistry profiles and physical examinations showed that the peptide did not induce any systemic toxicity. To determine how we obtained these unprecedented results, we focused on the mechanism of CD200AR-L/CD200AR binding. We discovered DAP10/12 signaling pathways and CD200ARs are upregulated, while the inhibitory CD200R1 is downregulated. We discovered the molecular connection between CD200, PD-1 and CTLA4. We demonstrated that our murine and human CD200AR-L downregulates the inhibitory PD-1 and PD-L1 and inhibits the upregulation of CTLA4. Therefore, we attribute the success of CD200AR-L to the ability to concurrently modulate multiple immune checkpoints. We have now developed human GMP grade CD200AR-L peptides to develop an immunotherapy approach for patients with CNS tumors; we will conduct a Phase I trial utilizing the peptide ligand concomitantly with an allogeneic GBM6-AD cell line as a tumor vaccine and the adjuvant imiquimod.
RARE-47. CHARACTERIZATION OF ADULT MEDULLOBLASTOMA; A RETROSPECTIVE REVIEW OF 200 PATIENTS AT MD ANDERSON CANCER CENTER
Authors: Majd Nazanin , Mastall Max , Hess Kenneth , Fuller Greg , Alfaro-Munoz Kristin , Gule-Monroe Maria , Huse Jason , Khatua Soumen , Rao Ganesh , Sandberg David I , Wefel Jeffrey , Yeboa Debra , Zaky Wafik , Mahajan Anita , Puduvalli Vinay , Suki Dima , Weathers Shiao-Pei , Harrison Rebecca , DeGroot John , Penas-Prado Marta
Published: November 2019

INTRODUCTION

Prospective studies for adult medulloblastoma (MB) are scarce and management guidelines are largely derived from pediatric experience and retrospective data. However, adult MB is a distinct disease for which limited data exist regarding clinical characteristic, prognostic factors, outcome based on upfront treatment, or patterns of recurrence.

METHODS

200 patients (≥18 years at diagnosis) were identified from 1978 to 2017. Survival analysis was performed using the Kaplan-Meier method.

RESULTS

Median age at diagnosis 29 (18–63); 111 (55.5%) standard-risk (SR), 59 (29.5%) high-risk (HR), 30 (15%) unknown. 188 (94%) and 97 (48.5%) underwent radiotherapy and upfront chemotherapy, respectively. Median PFS: 6.28 years (4.9–11.2); median OS: 8.8 (7.8–12.4) years. Median time to first recurrence: 8.2 (5.1-not reached); 5-year recurrence-free rate: 71% in SR and 45% in HR patients. Survival after first recurrence: 2 years (1.64–2.4). Documented recurrence and risk group were associated with survival (HR 30.4, p< 0.0001 and 2.33, p< 0.001), but metastatic status and local vs. distant recurrence were not. The effect of upfront chemotherapy on survival did not reach statistical significance in SR patients. The use of chemotherapy regimens with or without vincristine or containing cisplatin vs. carboplatin, did not alter the survival outcome. In a subgroup of 57 SR patients who were seen at initial diagnosis and for whom complete staging and treatment information were available 3 and 5-year PFS were 94% (88%, 100%) and 76% (66%, 86%); OS at 5 years, 94% (87%, 100%).

CONCLUSION

No statistically significant difference was noted in outcome of patients treated without vincristine or with carboplatin instead of cisplatin, suggesting attenuated upfront regimens could be considered to reduce toxicity. Adult MB patients recur late and have a poor post-recurrence survival, therefore long-term follow-up, development of molecular risk-adjusted upfront treatment, and optimization of rescue treatments are needed.
ANGI-10. CHEMOTHERAPEUTIC STRESS INDUCES TRANSDIFFERENTIATION OF GLIOBLASTOMA CELLS TO PROMOTE VASCULAR MIMICRY
Authors: Baisiwala Shivani , Auffinger Brenda , Caragher Seamus , Shireman Jack , Ahsan Riasat , Park Cheol , Ahmed Atique
Published: November 2019

Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumor affecting adults, with a median survival of approximately 21 months after diagnosis. A key factor underlying the limited efficacy of current treatment modalities is the remarkable plasticity exhibited by GBM cells, which allows them to effectively adapt to changes induced by our current treatment strategies. In addition to their plasticity, GBM tumors are also highly vascularized with aberrant vessels that further promote its aggressiveness. Recent research has demonstrated that GBM cells have the ability to transdifferentiate into endothelial cells (ECs), which suggests that GBM cells may use their properties of plasticity and vascularity in concert, leading to the creation of tumor-derived blood vessels. The mechanism behind this transdifferentiation remains unclear. Here, we show that treatment with temozolamide (TMZ)-based chemotherapy (the current standard of care) induces time-dependent increases in expression of markers for glioma stem cells (GSCs) and immature and mature ECs over 8 days of treatment (p < .001) in multiple patient-derived xenograft (PDX) lines. In addition, GBM tumors growing as orthotopic xenografts in nude mice showed significantly increased expression of GSC markers (CD15 and CD133) and EC markers (CD105 and CD144) after 8 days of TMZ treatment (p < .01). Ex-vivo FACS analysis of these orthotopic xenografts showed the presence of immature and mature EC populations in addition to GSC populations. To assess the functionality of these increased EC populations, a tube forming assay was performed. Results showed that the tube forming capacity of PDX lines was significantly increased (p < .01) after therapy. Furthermore, immunofluorescence analysis revealed increased tumor-derived vessels in TMZ-recurrent tumors. Overall, this study identifies chemotherapeutic stress as a new driver of transdifferentiation of tumor cells to endothelial cells and highlights cellular plasticity as a key player in therapeutic resistance and tumor recurrence.
CBMT-04. MOLECULAR MECHANISM OF OLIG2-CDK2 INTERACTION IN GLIOMA CELLS
Authors: Saito Norihiko , Hirai Nozomi , Aoki Kazuya , Sato Sho , Suzuki Ryo , Hiramoto Yu , Nakayama Haruo , hayashi Morito , Sakurai Takatoshi , Iwabuchi Satoshi
Published: November 2019

Oligodendrocyte transcription factor 2 (OLIG2) promotes proliferation of normal neural stem/progenitor cells and glioma cells. However, the mechanisms underlying the regulation of OLIG2 remain largely unknown. Here we identified OLIG2 as a critical phosphorylation target for cyclin-dependent kinase 2 (CDK2). CDK2-mediated OLIG2 phosphorylation stabilizes OLIG2 protein from proteasomal degradation. Phosphorylated OLIG2 binds to the E-Box regions of p27 promoter and represses p27 transcription, which in turn activates CDK2 in positive feedback manner. CDK2-mediated OLIG2 phosphorylation promotes cell cycle progression, cell proliferation, and tumorigenesis. OLIG2 inhibition disrupted cell cycle control mechanism by decreasing CDK2 and elevating apoptosis-related molecules. Inhibition of CDK2 activity disrupted OLIG2-CDK2 interactions and attenuated OLIG2 protein stability. In addition, OLIG2-high glioma initiating cells are highly sensitive to CDK2 inhibitor treatment, indicating that OLIG2 can be a biomarker for personalized treatment for glioblastoma patients with CDK2 inhibitors. Further investigation on these mechanisms may lead to novel targeted therapy on GBMs with high OLIG2 expression.
CBMT-12. FOCAD LOSS IMPACTS MICROTUBULE ASSEMBLY, G2/M PROGRESSION AND PATIENT SURVIVAL IN ASTROCYTIC GLIOMAS
Authors: Brand Frank , Förster Alisa , Kosfeld Anne , Bucher Martin , Thomé Carina , Raab Marc , Westphal Manfred , Pietsch Torsten , von Deimling Andreas , Reifenberger Guido , Claus Peter , Hentschel Bettina , Weller Michael , Weber Ruthild
Published: November 2019

In search of novel genes associated with glioma pathogenesis, we have previously shown that KIAA1797/FOCAD is frequently deleted in malignant gliomas and that the encoded focadhesin functions as a tumor suppressor impacting proliferation and migration of glioma cells in vitro and in vivo. Here, we examine an association of FOCAD copy number loss with overall survival of patients with astrocytic gliomas, and address the molecular mechanisms that govern the suppressive effect of focadhesin on glioma growth. FOCAD loss was associated with inferior outcome in patients with isocitrate dehydrogenase 1 or 2 (IDH)-mutant astrocytic gliomas of WHO grades II-IV. Multivariate analysis considering age at diagnosis, IDH mutation and MGMT promoter methylation status confirmed FOCAD loss as a prognostic factor for overall survival. Using a yeast two-hybrid screen and pull-down assays, we identified tubulin beta-6 and other tubulin family members as novel focadhesin-interacting partners. We demonstrate that tubulins and focadhesin co-localize at the centrosome and that focadhesin is enriched in proximity to centrioles. Focadhesin is recruited to microtubules via its interaction partner SLAIN motif family member 2 and reduces microtubule assembly rates, possibly explaining why focadhesin decreases cell migration. During the cell cycle, focadhesin levels peak in G2/M phase and influence time-dependent G2/M progression possibly via polo like kinase 1 phosphorylation, providing an explanation for focadhesin-dependent cell growth reduction. We conclude that FOCAD loss may promote biological aggressiveness and worsen clinical outcome of diffuse astrocytic gliomas by enhancing microtubule assembly and accelerating G2/M phase progression.
CBMT-19. THE ALTERNATIVE LENGTHENING OF TELOMERE (ALT) MECHANISM PROVIDES COLLATERAL SENSITIVITY TO LETHAL TELOMERIC FUSION INDUCED BY TRAPPING PARP INHIBITORS
Authors: Mukherjee Joydeep , Dalle-Ore Cecelia , Johanessen Tor-Christian , Pandita Ajay , Ohba Shigeo , Cahill Daniel , Pieper Russell O
Published: November 2019

A subset of human tumors, including all IDH1-mutant astrocytomas, use a homologous recombination-based alternative lengthening of telomere (ALT) pathway to resolve telomeric dysfunction in the absence of TERT. Because ALT is not used by normal cells, targeting of the process may provide new therapeutic options for patients with ALT-dependent tumors. We here report that reliance on the ALT mechanism makes tumors collaterally hypersensitive to clinically-available trapping PARPi (t-PARPi). Specifically we noted that astrocytoma cells dependent on the ALT-mechanism (IDH1-mutant and ATRX-deficient genetically-modified human astrocytes and MGG119 PDX) were significantly more sensitive to trapping PARPi than matched ALT-independent isogenic ATRXWT astrocytes and MGG152 PDX cells, respectively) both in vitro and in vivo. Surprisingly this hypersensitivity was not associated with BRCA-ness, the extent of PARP inhibition, or with t-PARPi-created genomic DNA damage as is the case in most PARPi-sensitive populations. Rather the enhanced activity of t-PARPi in ALT-dependent cells was associated with a novel t-PARPi-induced, lethal telomere fusion. Furthermore, the extent of chromosomal fusion was proportional to the PARP-trapping ability of the five PARP inhibitors tested, and could be prevented by exogenous expression of TERT, which eliminated reliance on ALT but did not alter levels of PARPi-induced genomic DNA damage. The extent of tPARPi-induced telomeric fusion in ALT-dependent cells, which could be directly measured in small amounts of DNA using a q-PCR approach, was also directly proportional to tPARPi-induced cell death in vitro and to prolonged survival of tumor-bearing mice in vivo. These results therefore identify clinically available tPARPi as a new treatment modality for a select and easily genetically definable group of ALT tumors, and also define telomeric fusion as a biomarker of drug action in these tumors.