bluuebunny/crossref_metadata_2025 huggingface dataset:
TMIC-47. INHIBITION OF GLIOBLASTOMA GROWTH THROUGH TUMOR-MICROENVIRONMENT CROSSTALK USING CLINICALLY SUITABLE NANOBIOCONJUGATE
Authors: Galstyan Anna , Klymyshyn Dmytro , Patil Rameshwar , Ding Hui , Shatalova Ekaterina , Holler Eggehard , Ljubimov Alexander , Black Keith , Sun Tao , Ljubimova Julia
Published: November 2019

Tumor environment in glioblastoma (GBM) is a dynamic interactive complex between tumor, immune and stem cells and extracellular matrix (ECM). In 226 patient glioma samples, we found a clinical correlation between expression of tumor vascular laminin-411 (α4β1γ1) and cancer stem cell (CSC) markers: Notch pathway members, CD133, Nestin, and c-Myc, with faster tumor recurrence and shorter survival of patients (Tao S, et al, Cancer Res., 2019). Novel nanotechnology approach to block trimeric ECM laminin-411 was developed for GBM treatment in experimental and preclinical models on human U87MG and LN229, and patient-derived TS543 and TS576 GBM cell lines. Nanobioconjugates (NBC) based on natural polymer, poly(β-L-malic acid), with antisense against laminin-411 α4 and β-chains, endosome escape unit (Ding H, et al, PNAS, USA, 2010), antibodies for blood-brain barrier (BBB) crossing and tumor targeting was characterized for toxicity and biodistribution according to FDA guidelines. Ex vivo depletion of laminin-411 α4 and β1 chains with CRISPR/Cas9 in human GBM cells led to reduced growth of intracranial tumors in mice, and significantly increased survival in hosts compared to mice with untreated cells. A nanobioconjugate potentially suitable for clinical use and capable of crossing BBB was designed to block laminin-411 expression. In biodistribution studies the NBC labeled with 125I on tyrosines of attached antibodies was accumulated in GBM but not in healthy brain tissue. Nanobioconjugate treatment of mice carrying intracranial GBM significantly increased animal survival and inhibited multiple CSC markers, Notch signaling system through the b1 integrin-Dll4 (Notch ligand) pathway. No toxicity revealed in 4 naïve Cynomolgus macaques after administration of three therapeutic 1X and acute 10X dosages of NBC. Conclusion: An efficient strategy of GBM treatment was developed via targeting a critical component of the tumor microenvironment, laminin-411, which is independent of heterogeneous genetic mutations in glioblastomas. Support: NIH grants U01CA151815, R01CA188743, R01CA206220, R01CA209921.
TMIC-49. ABROGATING CD70 EXPRESSION IN GBM RESULTS IN A REDUCED IMMUNOSUPPRESSIVE TUMOR MICROENVIRONMENT
Authors: Tao Haipeng , Jin Linchun , Mendez-Gomez Hector , Long Yu , Na Meng , Hou Alicia , Karachi Aida , Lin Zhiguo , Deleyrolle Loic , Sayour Elias , Mitchell Duane , Huang Jianping
Published: November 2019

BACKGROUND

We found that CD70, as an immune modulator, in GBM plays a critical role in immunosuppression and tumor progression. Although CD70+ tumors recruit more CD3+ T cells than CD70— tumors do in patients with GBM, CD70 on GBM is also found to be involved in promoting CD8+ T cell death. The experiments by overexpressing or silencing CD70 in a primary tumor demonstrate that it can alter cell growth, survival, migration, and morphology of GBM cells. CD70 is negatively correlated with survival in patients with gliomas. These results suggest that CD70 is involved in immunosuppression in GBM.

OBJECTIVE

To determine if abrogating CD70 in tumor using CD70CAR-T cells could reverse the immunosuppressive microenvironment and enhance overall endogenous tumor immunity against both CD70+ and CD70— tumors, which might help to overcome a key obstacle— tumor-heterogeneity using single-targeted CAR-T cell therapy.

METHODS

CD70 was overexpressed (~75% positivity) in KR158 GBM line. Murine CD70CAR T cells were used to eliminate CD70+ tumors in an immunocompetent orthotopic tumor mouse model. Tumor-bearing mice were administered the CD70CAR T and vector-tranduced T cells, followed by IVIS imaging for tumor growth. The presentation and phenotype of CAR T cells and endogenous immune cell populations in tumors and spleens were measured.

RESULTS

Five weeks post treatment, CD4+ T cells were found to be the dominant T cell population in tumors for both CAR-T and endogenous T cells. While the CAR-T cells shrank the tumors, fewer PD-1 expressing endogenous T cells, as well as granulocytic MDSC, but not monocytic MDSC were observed in the tumor (not in spleen) for the CAR-T group, compared to the vector group. No significant changes were seen for NK cells and Tregs between the groups.

CONCLUSION

This study suggests that eliminating CD70+ tumor cells may reverse the immunosuppressive landscape of the tumor microenvironment.
TMIC-55. CHARACTERIZATION OF TUMOR-MICROENVIRONMENT INTERACTIONS IN GLIOBLASTOMAS AT THE SINGLE-CELL LEVEL
Authors: Rao Rohit , Zhang Feng , Verma Ravinder , Wang Jincheng , Xin Dazhuan , Lu Richard
Published: November 2019

Glioblastomas are malignant brain tumors that carry a poor prognosis. The tumor microenvironment has been identified as an important regulator of tumor growth and may represent a novel target for therapy. Transcriptional subtypes of glioma are a major source of heterogeneity of expression in gliomas. Gliomas are highly heterogeneous diseases and can be classified into different subtypes including proneural, classical and mesenchymal tumors. We hypothesized that different subtypes of glioma will have different microenvironmental composition and exhibit distinct responses to therapies. To understand whether gliomas induced by different oncogenic drivers affect microenvironment composition, we induced mouse gliomas using a PDGFB and dnp53 driver to model proneural glioma and HRasV12 and dnp53 to model mesenchymal glioma, respectively. We performed single cell transcriptomic profiling to characterize the tumor microenvironment in these glioma models. We found that in the PDGFB/dnp53 glioma model had a large microglia contribution with about 30% tumor-associated microglia. In contrast, the HRasV12/dnp53 glioma model had only sparse microenvironmental cells. In addition, microglia in each model displayed subtype-specific gene expression programs, with microglia in the HRasV12/dnp53 tumor model expressing increased antigen presenting genes while increased levels of osteopontin in the PDGFB/dnp53 tumor model. To determine the tumor-microenvironment interactions, we performed receptor-ligand analysis using CellPhoneDb to identify secretory ligands that support tumor cell growth in microenvironmental cells. We found that tumor-associated pericytes are an important source of growth factor ligands in both PDGFB/dnp53 and HRasV12/dnp53 glioma models. We are investigating the contribution of microglia and pericytes to tumor growth and survival through cell depletion and pharmacological inhibition and determining whether the differences in tumor microglia between the models affects sensitivity to therapies including immunotherapy. Understanding how tumor-intrinsic signaling modulates microenvironment niches and tumor-microenvironment communications aids rational design of combinations targeting the malignant brain tumors.
ACTR-68. FEASIBILITY STUDY OF THE EMULATE THERAPEUTICS™ VOYAGER SYSTEM IN PATIENTS WITH RECURRENT GLIOBLASTOMA (GBM)
Authors: Barkhoudarian Garni , Badruddoja Michael , Blondin Nicholas , Chen Ricky , Chowdhary Sajeel , Cobbs Charles , Dowling Anthony , Duic Paul , Paul Flores John , Fonkem Ekokobe , McClay Edward , Nabors Louis , Salacz Michael , Vaillant Brian , Kesari Santosh
Published: November 2019

BACKGROUND

The EMulate Therapeutics Voyager system is an investigational non-sterile, non-invasive, non-thermal, non-ionizing, portable, home-use medical device that uses a specific, localized ultra-low radio frequency energy (ulRFE®) cognate for the treatment of brain cancer.

METHODS

This ongoing, open-label, multi-center study (NAT-101) is being conducted in the US and Australia in patients with recurrent GBM. There are 3 treatment groups: 32 patients treated with Voyager alone, 43 patients treated with Voyager + Investigator’s choice of anti-cancer therapy, and 21 patients treated with Voyager+lomustine+/-bevacizumab. The objective of the study is to assess if the Voyager is a safe and feasible treatment for recurrent GBM. The primary outcome measure is safety, assessed by the incidence and evaluation of adverse events (AEs) associated with the Voyager. The secondary outcome measures are progression-free survival and overall survival.

RESULTS

Enrollment is closed, and long-term treatment and follow-up is ongoing. 96 patients were enrolled and treated. 82 patients reported at least one AE, and 18 AEs were assessed as device-related (mild-moderate; 12 headache, 2 vomiting, 1 nausea, 1 confusion, 1 insomnia, and 1 skin irritation). 31 patients reported at least one serious AE, and none were assessed as device-related. 33% of patients treated with Voyager alone and 36% of patients treated with Voyager + chemotherapy were progression-free after 6 months. 58% of patients treated with Voyager alone and 60% of patients treated with Voyager + chemotherapy remained alive after 6 months; median overall survival is 7 months (95% CI=4.4±14.3) in patients treated with Voyager alone and 10 months (95% CI=6.7±11.5) in patients treated with Voyager + chemotherapy.

CONCLUSIONS

The Voyager system appears to be safe and feasible for the treatment of recurrent GBM. Given that therapy is delivered non-invasively and no device-related serious adverse events were reported, further prospective study of the investigational device is planned.
TMIC-63. ENDOCAN BRIDGING THE GAP: TUMOR ENDOTHELIAL CELL SECRETOME AND THE VASCULATURE-PROXIMAL TUMOR EDGE
Authors: Bastola Soniya , Ghochani Yasmin , Pavlyukov Marat S , Ghosh Sadashib , Kurowsky Morgan , Kornblum Harley , Nakano Ichiro
Published: November 2019

BACKGROUND

Glioblastoma (GBM) is a highly invasive, angiogenic and therapeutically resistant primary brain tumor. It is impossible to completely resect the tumor, which subsequently leaves behind tumor “edge” that can act as seeds for recurrence. We recently reported the leading “edge” and tumor core have the presence of two distinct types of glioma stem-like cells (GSCs) that resemble proneural (PN) and mesenchymal (MES) subtypes, respectively. GSCs are enriched in perivascular niches, and vascular endothelial (VE) cells are known to provide paracrine factors, radioresistance properties to GSCs. Therapeutically, targeting GBM using an anti-angiogenic anti-VEGF inhibitor, Bevacizumab, did not aid in overall survival and instead resulted in aggressive MES phenotype. Hence, it is imperative to study this nexus in greater detail to develop novel targeted therapies for VE and GBM cells. The purpose of this study was to understand the molecular mechanisms emanating from VE cells that cause the invading “edge” to recur and determine if targeting these molecular cascades can provide therapeutic benefit.

RESULTS

Using unbiased approach to identify paracrine factors from GBM patient derived VE cells, we identified endocan, a vascular endothelial cell secreted molecule, as a pro-tumorigenic factor essential for neovascularization, radioresistance, and stemness of GBM edge tumor cells. Utilizing patient-derived and mouse glioblastoma sphere models and the corresponding intracranial tumor models, we demonstrate that endocan maintains the “edge”-located glioma stem cell signature and protects glioblastoma cells from radiation-induced differentiation and apoptosis. Mechanistically, we show that endocan is a novel ligand that interacts with PDGFRa and induce its phosphorylation, leading to phosphorylation of the downstream targets PI3K and MAPK in GBM.

CONCLUSIONS

Collectively, these findings demonstrate a novel signaling axis of endocan-PDGFRa in GBM that is activated by tumor endothelial cell and plays an essential role in glioma stem cells maintenance and radioresistance in tumor “edge”.
TMOD-01. CHARACTERIZATION OF PATIENT-DERIVED PRIMARY CELL LINES AND XENOGRAFTS FOR GLIOBLASTOMA
Authors: Kijima Noriyuki , Kanematsu Daisuke , Shofuda Tomoko , Nonaka Masahiro , Iwata Ryoichi , Fukai Junya , Inoue Akihiro , Sasayama Takashi , Tsuyuguchi Naohiro , Kawashima Toshiyuki , Higuchi Yuichiro , Suemizu Hiroshi , Mori Kanji , Kishima Haruhiko , Kanemura Yonehiro
Published: November 2019

Patient-derived primary cell culture and xenograft are essential tools for translational research for glioblastoma. However, characteristics of each patient derived cell line and xenograft is not extensively studied. In this study, we aim to analyze the characteristics of our glioblastoma patient-derived cell lines and xenografts based on cell surface markers and their differentiation patterns. We have established 20 glioblastoma primary cell culture lines by serum free medium containing EGF and bFGF and found that primary cell culture lines could be classified based on the expression of CD133 and CD44. Four cell lines had high expression of both CD133 and CD44. Eleven cell lines had high expression of only CD44, three cell lines had high expression of only CD133, two cell lines had low expression of both CD133 and CD44. In addition when we induce differentiation, these cell lines showed differentiation to both glial and neuronal differentiation, but differentiation patterns were different depending on each cell line. Four cell lines showed predominant neuronal differentiation and others showed predominant glial differentiation. We next investigated in vivo characteristics of glioblastoma patient derived xenografts from these established cell lines. We have injected these cell lines into NOD/Shi-scid IL2Rγ KO mouse and histopathologically analyzed characteristics of xenografts. Each xenograft well recapitulated histological features of original patients’ tumors and tumor cells remarkably invade through subventricular zone. These results suggest that glioblastoma patient derived primary cell lines and xenografts have different characteristics of cell surface marker expressions and differentiation patterns, thus can classify these cell lines depending on cell surface marker expressions and differentiation patterns. Further analysis is needed to examine the biological importance of the differences in cell surface marker expressions and differentiation patterns.
TMOD-05. IN VIVO REPROGRAMMING OF POSTMITOTIC NEURONS INDUCES MEDULLOBLASTOMA
Authors: Aiello Giuseppe , Tiberi Luca
Published: November 2019

It is widely accepted that the “cell of origin” of tumors has to possess a proliferative capacity. Particularly for brain cancer, the transition of neural progenitors to differentiated postmitotic neurons is considered irreversible in physiological and pathological conditions. Therefore, postmitotic neurons have not been considered as suitable cell-of-origin for brain cancer. Here, we show that neurons reprograming may occur upon Shh activation and it leads to medulloblastoma (MB) formation in vivo. Shh MB is a cerebellar tumor, found in infants and adults that is thought to originate from cerebellar granule neuron progenitors. More recently, it was discovered that the two different forms of SHH MB are distinguished by different transcriptome/methylome levels suggesting that the adult SHH MB may originate from a different cell-of-origin. Relying on these data, we take advantage of a conditional Cre-Lox recombination system to recapitulate the human adult medulloblastoma pathogenesis in mice and demonstrate that post-migratory mature granule neurons can be reprogrammed in vivo. Furthermore, to define the contribution of chromatin changes in granule neurons dedifferentiation in response to Shh activation, we profiled changes in chromatin accessibility by ATAC-seq both in mouse tissue samples and also in human neurons. Upon Shh pathway activation we detected the presence of hyper-accessible chromatin regions corresponding to cis-regulatory elements specifically favouring activation of enhancers and super-enhancers. Our novel model of cancer development could explain the human SHH medulloblastoma onset in adult individuals where granule neuron progenitors are no more present. We strongly believe that our model represents an important starting point to study other tissues where postmitotic cells might originate cancer and therefore open a new field in cancer and stem cell biology.
TMOD-12. THE ROLE OF INTEGRIN α V AND CD44 IN GBM MIGRATION USING HUMAN ORGANOTYPIC SLICES
Authors: Binder Zev , Hyun Ji Kim Sarah , Wu Pei-Hsun , Giri Anjil , Gallia Gary , Pardo-Villamizar Carlos , Wirtz Denis
Published: November 2019

Current model systems used for GBM research include traditional in vitro cell line-based assays and in vivo animal studies. In vitro model systems offer the advantages of being easy to use, relatively inexpensive, and fast growing. However, these models lack key elements of the pathology they are attempting to model, including the biochemical and biophysical microenvironment and three-dimensional structure inherent to human brain tissue. In vivo model systems address these limitations, but have restrictions of their own. Species differences may result in non-applicable results and animal experiments are often not designed like clinical trials. Evidence of the limitations of current GBM models is found in the disparity between basic research findings and successful new treatments for GBMs in the clinic. Here we present an alternative model system for the study of human GBM cell motility and invasion, which features advantages of both in vitro and in vivo model systems. Using human organotypic brain slices as scaffolding for tumor growth, we explored the dynamic process of GBM cell invasion within human brain tissue. To demonstrate the utility of the model system, we investigated the effects of depletion of integrin α V (ITGAV) and CD44 on GBM cell motility. These two cell-surface proteins have been identified to have key functions in GBM cell motility. However, knockdown of ITGAV had little effect on tumor cell motility in organotypics while CD44 knockdown significantly reduced cell movement. Finally, we compare motility results from cells in human brain slices to those from cells growing on standard Matrigel and in mouse brain organotypics. We found significant differences in motility depending on the substrate in which the cells were moving. Our findings highlight the physiologic characteristics of human brain organotypics and demonstrate the use of real-time imaging in the ex vivo system.
TMOD-14. RADIOGRAPHIC, STIMULATED RAMAN HISTOLOGIC, AND MULTIPLEXED RNA-SEQUENCING ANALYSIS OF POST-TREATMENT RECURRENT HIGH-GRADE GLIOMAS
Authors: Save Akshay , Hollon Todd , Farooq Zia , Boyett Deborah , Hawkins-Daarud Andrea , Yoon Hyunsoo , Singleton Kyle , Clark-Swanson Kamala , Li Jing , Swanson Kristin , Freudiger Christian , Orringer Daniel , Lassman Andrew , Sims Peter , Grinband Jack , Canoll Peter , Bruce Jeffrey
Published: November 2019

High-grade gliomas (HGGs) nearly always recur after standard initial treatment, and the resulting mixture of recurrent tumor and treatment-induced reactive changes presents major diagnostic challenges. Anatomical imaging, such as MRI, cannot adequately distinguish progressive disease from treatment effect (pseudo-progression). Furthermore, there is marked intra-tumoral heterogeneity, such that some areas of a tumor may demonstrate necrotic treatment effect and others frank recurrence. Due to this difficulty reliably differentiating between these two clinical findings, analytic methods using multiple modalities are necessary to further our understanding of this disease process. To this end, we sought to correlate radiographic, histopathologic and molecular features of surgically sampled post-treatment suspected recurrence to identify markers distinguishing tumor growth from treatment effect. We performed Stimulated Raman Histology (SRH) imaging and highly multiplexed RNA-sequencing (PLATE-seq) on 84 MRI-localized biopsies from 39 patients with clinically suspected recurrent HGG. The SRH images were classified as recurrent tumor or gliotic/reactive tissue using a convolutional neural network trained on an independent cohort including a large set of recurrent HGG, and an automated cell-counting algorithm was used to quantify cellularity from the SRH image of each sample. Differential gene expression analysis of the PLATE-seq data was used to identify gene sets that distinguish recurrent tumor from treatment effect, and single sample gene set variation analysis (GSVA) was used to further assess the molecular and cellular composition of each MRI-localized sample. The histopathologic and molecular features of each sample were also correlated with the MRI features of the corresponding biopsy sites, and this data is currently being used to train machine learning models that predict the distribution of recurrent tumor and treatment-induced reactive changes within a patient’s radiographic lesion. These predictive radiomic models will help to guide neurosurgical sampling, and improve our ability to monitor glioma progression and response to therapy.
TMOD-16. MULTIFUNCTIONAL NANOPARTICLES USED FOR MAGNETIC RESONANCE/NIR FLUORESCENCE DUAL-MODAL IMAGING AND CHEMOTHERAPY OF GLIOMA
Authors: Zhao Shiguang
Published: November 2019

PURPOSE

Glioma is the most common malignant brain tumor and infamous for its high invasiveness and lethality. Therefore, plenty of techniques like intraoperative MRI (iMRI) and fluorescence-guided surgery were performed to improve the surgical resection rate of glioma. In addition, the chemotherapy effect of glioma was severely restricted because of the low blood-brain barrier (BBB) permeability of traditional therapeutic drugs. Doxorubicin (DOX) is a widely used antineoplastic drug, but its application in glioma therapy is prevented by the BBB. Thus, it is urgent to develop novel diagnostic methods and drug delivery systems to improve glioma treatment effect.

MATERIALS AND METHODS

In this study, we constructed a multifunctional nanotheranostic agent which integrated MR imaging, fluorescence imaging and targeting chemotherapy for glioma by encapsulating iron oxide nanoparticles, DOX and indocyanine green (ICG) with PEGylated phospholipid.

RESULTS

The obtained multifunctional were proved with an average diameter of 22.9 nm. In vitro cell experiments demonstrated that the nanoparticle effectively enhanced cellular uptake of DOX compared with that of free DOX. In vivo MR and fluorescence imaging not only demonstrated that the nanotheranostic agent effectively crossed the BBB and selectively accumulated at the tumor area, but also easily monitored the real-time therapeutic outcome. Among all treatment groups, C6 glioma-bearing rats treated with nanoparticles exhibited the maximal degree of efficacy, including the longest survival times and smallest tumor volume.

CONCLUSION

All these results suggested that the multifunctional nanoparticles could be simultaneously used for iMRI and fluorescence-guided surgery to increase the resection rates, as well as delivering chemotheraputic drugs to tumor site to improve therapeutic effect. We believe that this multifunctional nanoparticle might serve as a potential theranostic treatment for glioma in the near future.
TMOD-19. ELUCIDATING THE RESISTANCE TO IMMUNOTHERAPY IN BRAIN TUMORS USING A HUMANIZED MICROBIOME MOUSE MODEL
Authors: Dees Kory , Koo Hyunmin , Hakim Joseph , Fraser Humphreys J , Crossman David , Crowley Michael , Nabors Louis , Benveniste Etty , Morrow Casey , McFarland Braden
Published: November 2019

Although the immunotherapy anti-PD-1 works well in glioblastoma (GBM) pre-clinical mouse models, the therapy has not demonstrated a similar efficacy in patient clinical trials. Recent studies have linked the gut microbe composition to tumor growth and response to immunotherapy in some cancers. To date, all GBM pre-clinical studies have been done in mouse models using mouse gut microbiomes. There are significant differences between mouse and human microbial gut compositions, with up to 85% of gut bacteria found in laboratory mice not found in humans. Because it is known that the gut microbe composition can impact the immune system, we hypothesize that the non-responsiveness of GBM patients to immunotherapy may be due to the composition of the gut microbiome. Therefore, we have generated a humanized microbiome mouse model in which mice have been colonized by human donor microbes in their GI tract (two different healthy human donors (HuM1 and HuM2)). In preliminary results, we have found that HuM1 mice are resistant to anti-PD-1, while HuM2 mice are responders to anti-PD-1 in the GL261 syngeneic intracranial model. These mice are genetically identical and only differ in gut microbiome composition. Furthermore, we found that HuM2 mice exhibited a significant increase in cytotoxic CD8+T-cells producing IFN-γ and significant increased CD8+/Treg ratio in the spleen following anti-PD-1 treatment, which was not observed in the HuM1 mice. When testing the efficacy of standard of care temozolomide (TMZ) in our humanized mice, we found that TMZ significantly prolonged survival of both HuM1 and HuM2 mice with intracranial tumors. However, HuM2 mice exhibited superior efficacy (p< 0.001; 57% survival), compared to HuM1 mice (p< 0.01; 0% survival). We are extending these studies to analyze additional humanized microbiome lines as well as GBM patient donor lines to more accurately understand individual responses to tumor growth and responsiveness to therapies.
TMOD-27. A NEURAL CREST CELL SUBPOPULATION UNDERLIES INTRATUMOR HETEROGENEITY IN MENINGIOMA
Authors: Magill Stephen , Vasudevan Harish , Seo Kyounghee , John Liu S , Hilz Stephanie , Villanueva-Meyer Javier , Choudhury Abrar , Demaree Benjamin , Lim Daniel , Braunstein Steve , Ann Oberheim-Bush Nancy , Ullian Erik , Aghi Manish , Theodosopoulos Philip , Sneed Patricia , Abate Adam , Berger Mitchel , McDermott Mike , Costello Joseph , Raleigh David
Published: November 2019

BACKGROUND

Meningiomas are the most common primary intracranial tumor, and high grade meningiomas are resistant to most cancer therapies. Intratumor heterogeneity is a recognized source of resistance to treatment in numerous malignancies. Thus, we hypothesized that investigating molecular heterogeneity in meningiomas would elucidate biologic drivers and shed light on tumor evolution and mechanisms of resistance.

METHODS

We collected 86 spatially distinct samples at the time of resection from 13 meningiomas. Seven meningiomas were WHO grade I (46 samples), three were grade II (22 samples), and three were grade III (18 samples). Seven meningiomas were sampled at the time of salvage surgery (48 samples), and 6 were sampled at the time of initial diagnosis (38 samples). We performed multiplatform molecular profiling of these samples to identify drivers of intratumor heterogeneity, and validated our results using meningioma cells co-cultured with human cerebral organoids and RNA sequencing of paired primary and recurrent meningiomas.

RESULTS

Using bulk RNA sequencing, DNA methylation profiling and phylogenetic analysis of spatially distinct samples, we discovered significant transcriptomic, epigenomic and genomic heterogeneity in meningioma. In particular, we identified chromosomal structural alterations and differences in immune and neuronal signaling that underlie clonal evolution in high grade tumors. Using MRI-stratified bulk RNA sequencing, single nuclear RNA sequencing, RNA sequencing of paired primary and recurrent meningiomas, and live cell microscopy and single cell RNA sequencing of meningioma cells in co-culture with human cerebral organoids, we revealed a rare meningioma cell subpopulation with strong transcriptional concordance to the neural crest, a multipotent embryonic tissue that forms the meninges in development.

CONCLUSIONS

These data suggest that misactivation of a developmental cell population underlies intratumor heterogeneity in meningioma and that expression of neural crest and immediate early genes are an important step in meningeal oncogenesis.
TMOD-29. A MOUSE MODEL OF FGFR3-TACC3 UNCOVERS MECHANISMS OF GLIOMAGENESIS AND MAINTENANCE
Authors: Fnu Tala , Shi Peiguo , Zhang Jing , Iavarone Antonio , Lasorella Anna
Published: November 2019

Glioblastoma harboring Fibroblast Growth Factor Receptor 3 (FGFR3)-Transforming Acidic Coiled-Coil containing 3 (TACC-3) (FGFR3-TACC3) fusion is a distinct molecular subclass of tumors that can be targeted by FGFR kinase inhibitors. We generated a knock-in mouse in which the expression of FGFR3-TACC3 is doxycycline inducible and reversible. The tetO-FGFR3-TACC3-IRES-GFP cassette was placed into the Rosa26 locus and the FGFR3-TACC3 knock-in strain was intercrossed with GFAP-rtTA*M2 mice to trigger expression of the tetracycline transactivator (and the fusion gene) from the GFAP promoter. To recapitulate the genetic lesions that are more frequently associated with FGFR3-TACC3 in human glioblastoma, we also intercrossed the tetO-FGFR3-TACC3-IRES-GFP;GFAP-rtTA*M2 mice with TP53+/-or Ink4A+/-mouse strains. Both strains developed aggressive and infiltrating gliomas within 90 days after induction of FGFR3-TACC3 by doxycycline containing diet. Tumors occurred with a prevalence of ~50% and were found almost exclusively at two brain locations: the lateral septum and the neuro-epithelium adjacent to the fimbria of the hippocampus, thus recapitulating the restricted expression of endogenous FGFR3 in the ventral telencephalon and ganglionic eminence during development. The FGFR3-TACC3-positive glioma resembled human glioblastoma as they exhibited marked invasiveness and vascularization, elevated proliferative index and positivity for Nestin and GFAP. Rapid tumor progression caused appearance of neurological symptoms and death within few weeks. Doxycycline withdrawal from the diet of mice diagnosed with brain tumors by MRI resulted in rapid loss of FGFR3-TACC3 from glioma cells, marked inhibition of tumor growth with essentially complete glioma regression in some cases and recovery of general and neurological clinical symptoms. Our findings validate FGFR3-TACC3 as powerful oncogene that drives development of high-grade glioma from distinct areas of the brain. They also provide an accurate pre-clinical model in which glioma maintenance requires continuous expression of the fusion gene, thus supporting therapeutic targeting of the fusion protein in patients with FGFR3-TACC3-positive glioblastoma.
TMOD-30. CHARACTERIZATION OF AN ALTERNATIVELY SPLICED NTRK2 VARIANT IN GLIOMAS
Authors: Pattwell Siobhan , Arora Sonali , Cimino P J , Szulzewsky Frank , Hoellerbauer Pia , Hoffstrom Benjamin , Boiani Norman , Ozawa Tatsuya , Bolouri Hamid , Correnti Colin , Silber John , Paddison Patrick , Holland Eric
Published: November 2019

Recent work has uncovered oncogenic TRK fusions in a wide range of cancer types, including adult and pediatric gliomas. With some exceptions, many of these fusions tend to occur at very low frequencies below 1–2%, with unclear clinical significance, yet they highlight a potentially important and rapidly evolving role for NTRK1, NTRK2, NTRK3 in glioma biology. Basic scientific and clinical investigation surrounding TRKs’ role in cancer has often been hindered due to the nonspecific nature of antibodies and kinase inhibitors, combined with a lack of precise exon-specific expression data from patient populations. Tropomyosin receptor B (TrkB), encoded by the NTRK2 gene, is most known for its established roles in neuronal survival, proliferation, differentiation, apoptosis, learning, and memory. TrkB exerts diverse effects on cellular outcomes through interactions with downstream signaling cascades and has been shown to exhibit complex alternative splicing patterns. Here we show a novel role for a TrkB splice variant in human gliomas via NTRK2 transcript analyses in normal human brain and gliomas using The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression Project (GTEx). Using a novel antibody designed against this splice variant, immunostaining shows altered receptor localization within human gliomas compared to normal human brain. This NTRK2 splice variant enhances PDGF-driven gliomas in vivo in an RCAS-TVA mouse model and augments PDGF-induced signaling in vitro. Through the lens of NTRK2, these results highlight the importance of expanding upon whole gene-level and kinase-fusion analyses to explore TRK splicing in basic and translational research.
TMOD-33. AN INTEGRATED APPROACH COMBINING MATHEMATICAL AND GENOMIC METHODS TO REVEAL THE OPTIMAL TIMING OF THERAPEUTIC INTERVENTION IN WHO GRADE II DIFFUSE GLIOMA
Authors: Aoki Kosuke , Yamamoto Takashi , Suzuki Hiromichi , Maeda Sachi , Ranjit Melissa , Motomura Kazuya , Nakamura Hideo , Narita Yoshitaka , Nakada Mitsutoshi , Deguchi Shoichi , Mizoguchi Masahiro , Momii Yasutomo , Muragaki Yoshihiro , Abe Tatsuya , Akimoto Jiro , Wakabayashi Toshihiko , Haeno Hiroshi , Natsume Atsushi
Published: November 2019

BACKGROUND

In WHO grade II diffuse gliomas (low-grade gliomas, hereafter called LGGs), chemotherapy and radiotherapy contribute to prolonged survival but could induce somatic mutations. The optimal timing of treatment in LGGs remain poorly understood. To delineate this, we designed a mathematical model for tumor growth and investigate the association among the treatment, malignant transformation (MT), and the accumulation of somatic mutations revealed by whole exome sequencing (WES) in LGGs.

METHODS

Totally, 290 patients with LGGs between 1990 and 2018 were analyzed. We assessed the statuses of IDH mutation and 1p19q co-deletion in all tumors. Among all, 114 patients (39%) underwent MT during follow-up periods (mean: 82.6 months). Tumor volume was evaluated with FLAIR and/or T2-weighted MRI. MT was evaluated with contrast-enhanced MRI and/or pathological diagnosis. To investigate the number of somatic mutations in a cohort of LGGs and their patient matched recurrence, WES was performed on 88 serial samples collected at least two time-points from 39 patients.

RESULTS

Oligodendroglioma, IDH-mutant and 1p/19q-codeleted (OD) showed longer transformation-free survival compared to other subtypes. An exponential model was chosen to estimate growth rate in LGGs, since the exponential model provided a better fit to our data as compared to a linear model. The growth rate significantly decreased in the middle of chemotherapy and after radiotherapy. By contrast, these treatments increased the number of somatic mutations identified by WES and the rate of MT in each subtype. The increasing number of mutations in recurrent tumors showed strong correlation with the rise in MT rate. Based on the growth rate and the risk of MT, optimal timing of treatments could be calculated for each genetic subtype.

CONCLUSIONS

The mathematical model and WES analysis delineates the optimal timing of treatments in each subtype, which will help to decide the treatment for LGGs.
SCIDOT-08. CHILDREN’S BRAIN TUMOUR DRUG DELIVERY CONSORTIUM (CBTDDC)
Authors: Rahman Ruman , Campbell Emma , Brem Henry , Pearl Monica , Green Jordan , Janowski Miroslaw , Walczak Piotr , Tyler Betty , Warren Katherine , Singleton Will , Mullen Alexander , Boyd Marie , Veal Gareth , Hargrave Darren , van Vuurden Dannis , Powell Steven , Battaglia Giuseppe , Vivanco Igor , Al-Jamal Khuloud , Walker David
Published: November 2019

INTRODUCTION

The brain tumour community has seen significant progress in the discovery of new therapeutic targets and anticancer drugs. Unfortunately, advances in how to deliver drugs to the brain lag behind. The blood-brain barrier restricts the entry of many small-molecule drugs and nearly all large molecule drugs that have been developed to treat brain disorders.

METHODS

Following an international CNS drug delivery workshop in 2016, we were awarded funding from Children with Cancer UK to launch the Children’s Brain Tumour Drug Delivery Consortium (CBTDDC; www.cbtddc.org; @cbtddc).

RESULTS

The CBTDDC launched in 2017 (in Europe and the US) to raise awareness of the challenge of drug delivery in childhood brain tumours, and to initiate and strengthen research collaborations to accelerate the development of drug delivery systems. We ran a Workshop on Drug Delivery to the Brain, attracting 52 delegates from the UK, Belgium, Spain and Portugal. We liaised with UK-based funders over the drug delivery agenda, and with UK policy makers. In the US, we jointly organised the SIGN2019 meeting and we are currently liaising with the leads of Project ‘All In’ DIPG about how we can lend our support to this project. As of June 2019, 150 individuals have registered with the consortium, representing researchers, clinicians, charities, patient groups and industry. These stakeholders represent 70 research institutions, covering 15 countries (France, UK, Italy, Sweden, The Netherlands, USA, Greece, Germany, Belgium, Cuba, Denmark, Spain, Portugal, Israel and Egypt). We host a freely accessible online collaborative research database, containing the details of over 70 researchers.

CONCLUSION

We believe that collaboration between clinicians and multi-disciplinary researchers is vital to solving the brain tumour drug delivery challenge. We hope to raise awareness of the CBTDDC, and to extend our invitation for collaborators to join the consortium, through SCIDOT’s unrivalled drug delivery platform.
ANGI-04. A NOVEL TROY-JAK1 SIGNALING COMPLEX IN GLIOBLASTOMA INVASION
Authors: Ding Zonghui , Kloss Jean , Tuncali Serdar , Tran Nhan , Loftus Joseph
Published: November 2019

Glioblastoma (GBM) is the most common and deadly malignancy of the central nervous system in adults with a median survival of about 15 months after diagnosis. Its aggressive and highly infiltrative nature renders the current standard treatment of maximal surgical resection, radiation, and chemotherapy relatively ineffective. Identifying the molecular events that regulate GBM migration/invasion is required to develop more effective therapeutic regimens to treat GBM. Expression of TROY, an orphan receptor of the TNFR superfamily, increases with increasing glial tumor grade, inversely correlates with patient survival, stimulates GBM cell invasion in vitro and in vivo, and increases resistance to temozolomide and radiation therapy. Conversely, silencing TROY expression inhibits GBM cell invasion, increases sensitivity to temozolomide, and prolongs survival in a preclinical intracranial xenograft model. Thus, the TROY signaling pathway represents an attractive therapeutic target. We previously reported that increased TROY expression strongly activates NF-kB. We have identified for the first time that TROY forms a unique signaling complex with JAK1. Interaction with TROY stimulates phosphorylation of JAK1 and significantly increases the activation of STAT3. TROY specifically associates with JAK1 as it does not associate with other JAK family members. Co-immunoprecipitation analysis demonstrated that TROY interacts with JAK1 through its cytoplasmic domain as a TROY variant without its extracellular domain associates with JAK1 while a TROY variant without a cytoplasmic domain fails to bind JAK1. Luciferase reporter assay confirmed that full length TROY or a variant lacking the extracellular domain are able to induce STAT3 activation, but not a TROY variant lacking the cytoplasmic domain. Pharmacological inhibition of JAK1 by the FDA approved inhibitor ruxolitinib or knockdown of JAK1 by siRNAs significantly inhibited TROY-induced STAT3 activation and GBM cell migration. Together, our data indicate that the TROY-JAK1 complex represents an unappreciated therapeutic target to inhibit glioma invasion and decrease therapeutic resistance.
SCIDOT-14. ENHANCING BRAIN RETENTION OF A KIF11 INHIBITOR SIGNIFICANTLY IMPROVES ITS EFFICACY IN A MOUSE MODEL OF GLIOBLASTOMA
Authors: Gampa Gautham , Kenchappa Rajappa , Mohammad Afroz , Parrish Karen , Kim Minjee , Sarkaria Jann , Rosenfeld Steven , Elmquist William
Published: November 2019

Glioblastoma, the most common and lethal of brain tumors, is both highly invasive and proliferative. This allows tumor cells to infiltrate into regions of the brain with an intact blood brain barrier and be protected from effective therapeutics. Thus, an ideal glioblastoma therapy needs to target cellular components that drive both invasion and proliferation, with inhibitors that penetrate the blood brain barrier. The mitotic kinesin KIF11 meets these criteria and it can be targeted with ispinesib, a highly specific small molecule inhibitor. However, to be effective, ispinesib needs to cross the blood brain barrier and be retained within brain long enough to target glioblastoma cells when they are vulnerable, during mitosis.. We have examined the factors that affect distribution of ispinesib to both brain and glioblastoma. We find that delivery of ispinesib is limited by P-gp and Bcrp-mediated drug efflux at the blood brain barrier. Consequently, ispinesib levels are significantly lower in the infiltrative tumor margin relative to the tumor core, where the blood brain barrier is defective. We also show that elacridar—an inhibitor of the P-gp and Brcp efflux transporters—enhances delivery of ispinesib, and that co-administration of ispinesib with elacridar markedly slows tumor proliferation and prolongs survival in a mouse model of this disease. These results demonstrate the feasibility and efficacy of combining a potentially ideal therapeutic with a compound that enhances brain retention of this therapeutic, and provides support for utilizing this approach in clinical investigations of KIF11 inhibitors in GBM.
SCIDOT-15. DISRUPTING THE BLOOD-BRAIN BARRIER IN NEURO-ONCOLOGY: INNOVATIONS, ACHIEVEMENTS, AND LESSONS LEARNED FROM CLINICAL TRIALS
Authors: Philtheos Justine , Abbasian Aram , Karmur Brij , Mansouri Alireza
Published: November 2019

BACKGROUND

The blood-brain barrier (BBB) presents a formidable challenge for the development of effective therapeutics in neuro-oncology. Several strategies for the disruption of the BBB have been investigated in humans. An in-depth analysis of the concepts, design, and outcomes from these trials can provide insight into optimizing strategies for safe, selective, and efficacious BBB disruption for drug delivery.

METHODS

The clinicaltrials.gov database was searched on June 9th, 2019 using the term blood-brain barrier. Results were screened for studies relevant to neuro-oncology. When available, linked publications were also reviewed for supplemental information. The Pubmed database was also searched for BBB disruption strategies, to identify publications not linked to a trial registry. Details regarding patient eligibility, intervention, comparators, outcomes and other design criteria were extracted.

RESULTS

Among 288 registered studies, 42 were relevant to neuro-oncology. Drug-based methods predominated (33/42) but there has been a surge in device-based methods with all registrations after 2015. Mannitol was the most common drug-based method (16/33, 5 Phase II), followed by RMP-7 (8/33, 3 Phase II), Ang1005 (7/33, 4 Phase II and one pending Phase III), and Regadenoson (2/33, one Phase 0 and one Phase I). MR-guided focused ultrasound was the most common device-based method (5/9), followed by MR-guide laser ablation (2/9), Sonocloud (1/9), and transcranial magnetic stimulation (1/9). All device studies have been early phase. Most early phase studies focusing on safety and tolerability met objectives. Some Phase II studies showed preliminary efficacy but control arms were lacking. Many Phase II studies have been terminated/suspended.

CONCLUSIONS

Diverse BBB disruption methods have been investigated and most appear to be safe and tolerable. Advanced phase studies focusing on survival differences have been limited by heterogeneous tumors and lack of control arms. Objective establishment of BBB disruption was limited. Concerted and standardized clinical trial efforts are needed.
SCIDOT-22. INTRACEREBROVENTRICULAR DELIVERY OF TUMOR-HOMING CYTOTOXIC HUMAN INDUCED NEURAL STEM CELLS FOR TREATMENT OF BRAIN METASTASES
Authors: Jiang Wulin , Mercer-Smith Alison , Bago Juli , Khagi Simon , Anders Carey , Hingtgen Shawn
Published: November 2019

INTRODUCTION

Non-small cell lung cancer (NSCLC) and breast cancer are the most common cancers that metastasize to the brain. New therapies are needed to target and eradicate metastases. We have developed genetically-engineered induced neural stem cells (hiNSCs) derived from human fibroblasts that selectively home to tumors and release the cytotoxic protein TRAIL. Building on these results, we explored the efficacy of hiNSC therapy delivered via intracerebroventricular (ICV) injections for the treatment of metastatic foci in the brain for the first time.

METHODS

We performed in vitro efficacy and migration assays in conjunction with in vivo studies to determine the migration, persistence, and efficacy of therapeutic hiNSCs against H460 NSCLC and triple-negative breast cancer MB231-Br tumors in the brain. Following the establishment of tumors in the brains of nude mice, hiNSCs were injected directly into the tumor or the ventricle contralateral to the tumor. The migration and persistence of hiNSCs were investigated by following the bioluminescence of the hiNSCs. The therapeutic efficacy of the hiNSCs was determined by following the bioluminescence of the tumor. RESULTS/

CONCLUSION

Co-culture results demonstrated that hiNSC therapy reduced the viability of H460 and MB231-Br up to 75% and 99.8% respectively compared to non-treated controls. In vitro migration assays showed significant directional migration toward both lung and breast cancer cells within 4 days. ICV-administered hiNSC serial imaging shows that cells persisted for >1 week in the brain. Fluorescent analysis of tissue sections showed that hiNSCs co-localized with lateral and contralateral tumors within 7 days. Using H460 and MB231-Br models, kinetic tracking of intracranial tumor volumes showed intratumoral or ICV-injected therapeutic hiNSCs suppressed the growth rate of brain tumors by 31-fold and 3-fold, respectively. This work demonstrates for the first time that we can effectively deliver personalized cytotoxic tumor-homing cells through the ventricles to target brain metastases.
SCIDOT-23. LOW INTENSITY PULSED ULTRASOUND ENHANCES BLOOD-BRAIN BARRIER OPENING AND IMPROVES RESPONSE TO IMMUNOTHERAPY FOR GLIOBLASTOMA
Authors: Sabbagh Aria , Marisetty Anantha , Ott Martina , Ling Xiaoyang , Barton Emily , Caruso Hillary , Kong Ling-Yuan , Rao Ganesh , Canney Michael , Heimberger Amy B
Published: November 2019

The blood-brain barrier (BBB) is a significant obstruction to the delivery of treatments for glioblastoma. Previous studies have demonstrated the use of Low Intensity Pulsed Ultrasound (LIPU) in combination with microbubbles as a safe and therapeutic method for temporary BBB disruption to enhance chemotherapeutic delivery to the tumor and surrounding brain parenchyma. Glioblastoma has minimal T cell infiltration. In this work, we investigated if LIPU sonications (1 MHz, 0.3 MPa, 120 s duration) could enhance T cell delivery to the tumor microenvironment and enhance immunotherapy. NSG mice with established EGFRvIII+U87 tumors were treated intravenously with bioluminescent labeled epidermal growth factor receptor variant III (EGFRvIII) expressing chimeric antigen receptor (CAR) T cells with and without ultrasound BBB disruption. Combining systemic CAR T cell administration with ultrasound BBB disruption, resulted in a significant increase in CAR T cell delivery to the mouse CNS after 12 (p<0.005) and 24 hours (p<0.001) associated with enhanced median survival. In a second murine model of C57BL/6 mice bearing intracerebrally implanted GL261 gliomas, mice treated with anti-PD-1 and ultrasound BBB disruption survived 58 days relative to 39 days of mice treated with only anti-PD-1. Long-term survivors in the anti-PD-1 and anti-PD-1+ ultrasound treatment groups all remained alive after contralateral hemisphere rechallenge with GL261 glioma cells. LIPU-induced BBB disruption increases the delivery of immune therapeutics to the tumor microenvironment with an associated increase in survival and is an emerging technique for enhancing novel therapies to the clinic.