bluuebunny/crossref_metadata_2025 huggingface dataset:
SCIDOT-02. A PHASE I STUDY OF CONVECTION-ENHANCED DELIVERY OF LIPOSOMAL-IRINOTECAN (ONIVYDE) USING REAL-TIME IMAGING WITH GADOLINIUM IN PATIENTS WITH RECURRENT HIGH GRADE GLIOMAS: RESULTS THUS FAR
Authors: Kumar Karishma , Butowski Nicholas , Aghi Manish , Bankiewicz Krystof , Bringas John , Ann Oberheim Bush Nancy , Chang Susan , Clarke Jennifer , Taylor Jennie , Martin Alastair , Berger Mitchell
Published: November 2019

BACKGROUND

Chemotherapy for high grade gliomas (HGG) is limited by the blood-brain-barrier (BBB). Convection enhanced delivery (CED) improves chemotherapy delivery by utilizing fluid convection obviating the challenges of crossing the BBB while minimizing systemic toxicity. CED of nanoliposomal-irinotecan (Onivyde) showed to be a superior delivery route for anti-tumor activity in animal models. An advance of this trial is the development and use of real time CED, which utilizes MRI to visualize the CED process with the aid of co-convected contrast agents, monitoring delivery into the brain and affording for corrective action.

METHODS

This is a 3 + 3 single dose escalation trial with 2 cohorts: 20mg/ml and 40mg/ml. Onivyde and GAD were co-infused via the same catheters in a one-time delivery. The total dose was personalized based on the patient’s tumor volume, and ranged from 20–680 mg of Onivyde, given via up to 4 catheters. Tumor diameters were allowed to be 1 – 4 cm, with injection volumes ranging from 2 – 17 mL of infusate.

RESULTS

13 patients have been treated on this protocol, all in under 5 hours. There were 9 GBs, 1 gliosarcoma, 2 AAs, and 1 oligoastrocytoma. Utilizing imaging software, we correlated pre-infusion modeling of the drug distribution with post-infusion imaging. A number of technical challenges were overcome by real time monitoring; the total volume of distribution (Vd), and the Vd to volume infused (Vi) ratio for each infusion was ~2. Of all patients, the only notable AE was encephalopathy, which was resolved.

CONCLUSIONS

Image-guided distribution allows for safe real-time placement and adjustment of CED cannula of Onivyde into patient’s brains. Such methods allow for maximum tumor coverage and warrant further studies with repeat dosing.
SCIDOT-04. REPLACEMENT OF MICROGLIA BY BRAIN-ENGRAFTED MACROPHAGES PREVENTS MEMORY DEFICITS AFTER THERAPEUTIC WHOLE-BRAIN IRRADIATION
Authors: Feng Xi , Gupta Sonali , Chen David , Boosalis Zoe , Liu Sharon , Gupta Nalin , Rosi Susanna
Published: November 2019

Microglia have a distinct origin compared to blood circulating myeloid cells. Under normal physiological conditions, microglia are maintained by self-renewal, independent of hematopoietic progenitors. Following genetic or pharmacologic depletion, newborn microglia derive from the local residual pool and quickly repopulate the entire brain. The depletion of brain resident microglia during therapeutic whole-brain irradiation fully prevents irradiation-induced synaptic loss and recognition memory deficits but the mechanisms driving these protective effects are unknown. Here, we demonstrate that after CSF-1R inhibitor-mediated microglia depletion and therapeutic whole-brain irradiation, circulating monocytes engraft into the brain and replace the microglia pool. These monocyte-derived brain-engrafted macrophages have reduced phagocytic activity compared to microglia from irradiated brains, but similar to locally repopulated microglia without brain irradiation. Transcriptome comparisons reveal that brain-engrafted macrophages have both monocyte and embryonic microglia signatures. These results suggest that monocyte-derived brain-engrafted macrophages represent a novel therapeutic avenue for the treatment of brain radiotherapy-induced cognitive deficits.
SCIDOT-06. TOWARDS EXCLUSIVELY LOCAL THERAPY OF GLIOBLASTOMA - ENGINEERING IL-12Fc WITH SUPERIOR TISSUE RETENTION AND MINIMAL SYSTEMIC EXPOSURE AFTER CNS ADMINISTRATION
Authors: Beffinger Michal , Schellhammer Linda , Pantelyushin Stanislav , Zimmermann Iwan , Egloff Pascal , Buch Thorsten , Seeger Markus , vom Berg Johannes
Published: November 2019

Intratumoral application of IL-12 overrides the prevailing glioblastoma (GB) associated immunosuppression and can trigger efficient anti-tumor responses. With clinical studies currently testing local expression of IL-12 in brain tumors, concerns on IL-12 systemic toxicity via leakage resurface. The fusion to an immunoglobulin heavy chain constant region (“Fc tag”) should increase tissue retention of IL-12. However, export of IL-12Fc into the blood via the neonatal Fc receptor (FcRn) could nevertheless lead to systemic exposure. Subsequent systemic recycling via FcRn could lead to gradually increasing and eventually toxic serum concentrations.

We analysed the effect of the Fc-tag on IL-12 tissue retention and evaluated whether FcRn also is involved in brain export and systemic recycling of IL-12Fc upon local delivery. Human or murine IL-12Fc was delivered in GB-bearing or naïve wt or FcRn-humanized mice (mFcRn-/- hFcRn tg) continuously via mini osmotic pumps or as bolus via convection-enhanced delivery (CED). Brain and blood concentration levels were assessed via ELISA. FcRn affinity of IL-12Fc mutants was assessed via ELISA and surface plasmon resonance.

We observed much higher tissue retention of IL-12Fc compared to unmodified IL-12, but also an FcRn-dependent gradual increase of IL-12Fc serum levels. Testing a battery of amino acid substitutions at the FcRn interaction interface, we discovered unique substitutions that largely abolish brain export and systemic accumulation while preserving IL-12Fc functionality, leading to an over 100-fold higher brain to blood ratio than unmodified IL-12. We currently test the impact on efficacy of local IL-12Fc and checkpoint brain tumor treatment in vivo.

Achieving high local concentrations at low to absent systemic exposure is an important prerequisite for a large therapeutic window for local treatment of neurologic diseases. The novel Fc-modifications present a promising platform for reducing systemic leakage of Fc-containing therapeutics in the context of continuous or intermittent CNS delivery beyond brain cancer therapy.
SCIDOT-07. ULTRASOUND DELIVERED ALBUMIN BOUND PACLITAXEL EXTENDS SURVIVAL IN MALIGNANT GLIOMA MODELS AND OUTPERFORMS ULTRASOUND DELIVERED CREMOPHOR PACLITAXEL IN BIO-DISTRIBUTION AND SAFETY
Authors: Sonabend Adam , Dmello Crismita , Chen Li , Arrieta Victor A , Gonzalez Edgar , Robert Kane J , Magnusson Lisa , Braun Aneta H , David James C , Horbinski Craig , Canney Michael , Carpentier Alexandre , Sottilini Frédéric , Desseaux Carole , Muzzio Miguel , Stupp Roger
Published: November 2019

Paclitaxel is anti-neoplastic agent shown to be extremely potent against glioblastoma in-vitro; however, it has yet to demonstrate antitumor activity in the clinic due to its inadequate brain penetration. Ultrasound-mediated drug delivery is an emerging new technology that transiently disrupts the blood-brain barrier to allow the passage of larger molecules that under physiological conditions would not reach the brain tissue. In this preclinical study, we investigated the ability of low intensity pulsed ultrasound (LIPU), delivered with the SonoCloud System (CarThera), to increase brain paclitaxel concentrations in a murine model. LIPU increased paclitaxel concentrations in the brain 300–500% after systemic administration of two different commercially available formulations of paclitaxel; paclitaxel dissolved in Cremophor (Taxol®) and albumin-bound paclitaxel (Abraxane®). The two formulations differed in their toxicity and biodistribution profiles with albumin-bound paclitaxel exhibiting increased tolerability and brain penetration. After sonication, albumin-bound paclitaxel increased survival in an orthotropic glioma model, whereas cremophor-paclitaxel induced central nervous system toxicity. Our experiments suggest that increased paclitaxel drug delivery by opening the BBB is feasible, and an effective anti-glioma treatment. Albumin-bound paclitaxel is the preferred formulation for further investigation with the SonoCloud system in the clinical setting.
SCIDOT-18. NANOTHERAPEUTICS FOR NEUROSURGICALLY-APPLIED DRUG DELIVERY
Authors: Vasey Catherine , Taresco Vincenzo , Smith Stuart , Alexander Cameron , Rahman Ruman
Published: November 2019

Design and implementation of innovative local drug delivery systems (DDS) may overcome current limitations in GBM treatment, such as the lack of therapeutic drug concentrations reaching residual GBM cells following surgery. Here we describe a novel DDS which utilises a bespoke mechanically engineered spray device, designed for safe surgical use, to deliver a mucoadhesive hydrogel containing chemotherapeutic nanoparticles (NPs) into the tumour resection margins. The overall aim is to spray a NP and polymer solution onto the resection cavity and potentially increase penetration of anti-cancer drugs within the 2 cm reoccurrence zone beyond the infiltrative margin. The mucoadhesive gel of choice, pectin, is currently used in other in vivo applications; however we have repurposed this for the brain. Pectin is biocompatible with GBM and human astrocyte cells in vitro and showed neither toxicity nor inflammation for up to 2 weeks upon orthotopic brain injection. Pectin is biodegradable in artificial CSF and is capable of being sprayed from the engineered device. A panel of polymeric, oil-based and polymer-coated NPs have been developed and optimised to maximise drug encapsulation of etoposide and olaparib as proof-of-concept for combination drug delivery. Etoposide/olaparib was chosen due to cytotoxicity from 5 GBM cell lines, including primary lines isolated from the invasive tumour margin (Mean IC50 of 1.1 µM and 8.3 µM respectively). The optimal NP/drug formulation (based on drug encapsulation, spray capability and bio-adhesiveness) will ultimately be assessed for tolerability and efficacy using orthotopic allograft and xenograft high-grade glioma models, including measurement of penetration of drug/nanoparticle in ex vivo murine and porcine brain using novel hybrid time-of-flight/Orbitrap TM secondary ion mass spectrometer (orbiSIMS) technology.
SCIDOT-20. ADAPTING ENGINEERED CELL THERAPIES TO UNDERSTAND AND OVERCOME GLIOBLASTOMA RESISTANCE USING INTEGRATED IN VIVO AND EX VIVO MODELS
Authors: Satterlee Andrew , Dunn Denise , Floyd Scott , Hingtgen Shawn
Published: November 2019

Genetically engineered neural stem cells (NSCs) are a promising therapy for the highly aggressive brain cancer glioblastoma (GBM), yet treatment durability remains a major challenge. We sought to define the events that contribute to dynamic adaption of GBM during NSC treatment and develop strategies to convert initial tumor kill into sustained GBM suppression. Using a unique hybrid tumor model treated with human skin-derived induced NSCs (iNSCs) releasing the pro-apoptotic agent TRAIL, we investigated how spatial distribution of tumor and iNSCs affects GBM adaption throughout recurrence. Serial bioluminescent imaging (BLI) was used to track tumor volumes in vivo, while a subset of mice were sacrificed 6, 13, and 20 days post-treatment to harvest brains and generate living ex vivo tissue slices. Live animal imaging showed iNSC-TRAIL treatment rapidly decreased tumor volumes when delivered into the primary tumor mass; however, minimal impact on tumor growth was observed when cells were delivered into distal regions of the brain. In contrast, high-resolution imaging of living brain sections showed extensive impacts of iNSC-TRAIL therapy that could not be visualized with BLI. The living slices showed iNSC-TRAIL treatment into the primary tumor decreased the solid, but not the invasive, tumor burden. Treatment into the lateral ventricles did impact tumor kill and was more effective at treating the invasive tumor burden and maintaining inhibition than treatment into the contralateral parenchyma. We next utilized the living tissue slices to explore the sensitivity of the recurrent tumors to TRAIL. When therapy was applied to slices harboring recurrent tumor, treatment again significantly reduced tumor volumes, suggesting tumors had not acquired TRAIL resistance. These results informed an additional in vivo survival study and subsequent PCR analysis of untreated and recurrent tumors, and combine the fidelity of in vivo studies with the speed and spatial resolution of living brain slice technology.
ANGI-05. ORIGIN OF MICROVASCULAR PROLIFERATION IN PILOCYTIC ASTROCYTOMA - MVP IN PILOCYTIC ASTROCYTOMA MIGHT PARTIALLY COMPRISE TUMOR-DERIVED CELLS
Authors: Yamashita Shinji , Takeshima Hideo , Watanabe Takashi , Yokogami Kiyotaka
Published: November 2019

Microvascular proliferation (MVP), an aberrant vascular structure containing multilayered mitotically active endothelial- and smooth-muscle cells/pericytes, is a histopathological hallmark of glioblastoma multiforme (GBM). Although MVP tends to be associated with high-grade glioma, it has also been detected in WHO grade I pilocytic astrocytoma (PA). However, little is known about the mechanism underlying its formation. Using TP53 point mutations as a marker for tumor-derived cells, we earlier reported that MVP was partially converted from tumor cells via mesenchymal transition. In the current study we used the KIAA1549-BRAF fusion gene as a marker to assess whether MVP in PA contained tumor-derived cells. cDNA synthesized from frozen tissue of six PA patients operated at our institute was analyzed to detect the KIAA1549-BRAF fusion gene by reverse transcription polymerase chain reaction (RT-PCR) assay. The breakpoint in the fusion gene was characterized by long and accurate PCR (LA-PCR) and Sanger sequencing of genomic DNA. Distinct tumor cells and cellular components of MVP were obtained by laser microdissection. For the qualitative and quantitative detection of the KIAA1549-BRAF fusion gene we performed genomic and digital PCR assays. Fluorescence in situ hybridization (FISH) was used to assess gene fusion in cellular components of MVP. Samples from three PA patients harbored the KIAA1549 exon 15, BRAF exon 9 fusion gene. In two patient samples with abundant MVP, RT-PCR assay detected strong bands arising from the KIAA1549-BRAF fusion gene in both tumor cells and cellular components of MVP. Digital PCR showed that vis-à-vis tumor tissue, its relative expression in cellular components of MVP was 42% in one- and 76% in another sample. FISH revealed amplified signals in both tumor cells and cellular components of MVP indicative of tandem duplication. Our findings suggest that in patients with PA, some cellular components of MVP may be tumor-derived.
SCIDOT-26. THE ROLE OF TUMOR-DERIVED GRANULOCYTE MACROPHAGE COLONY STIMULATING FACTOR (GM-CSF/CSF2) IN REGULATION OF MICROGLIA-DEPENDENT INVASION IN GLIOMAS
Authors: Poleszak Katarzyna , Pasierbinska Maria , Ellert-Miklaszewska Aleksandra , Wojtas Bartosz , Wojnicki Kamil , Kaminska Bozena
Published: November 2019

Brain resident immune cells (microglia) and peripheral macrophages accumulate in malignant gliomas and constitute for 30–50% of the tumor mass. These immune cells are polarized by factors released by glioma and become the pro-invasive, immunosuppressive cells that support tumor progression. We have previously found that tumor-derived granulocyte macrophage colony stimulating factor (GM-CSF/Csf-2) is a crucial factor controlling accumulation of microglia and macrophages in murine gliomas. The analysis of TCGA dataset revealed overexpression of the CSF2 gene (encoding GM-CSF) in a set of mesenchymal glioblastomas (most aggressive WHO grade IV gliomas) and its association with high immune gene expression. To study the role of GM-CSF in microglia-stimulated glioma invasion, we used a co-culture system, which mimics microglia interactions with tumor cells. We silenced the expression of CSF2 in glioma cells and found reduced microglia-dependent invasion of glioma cells. To translate those results into clinically relevant setting, we designed and tested humanized short peptides interfering with binding of GM-CSF to its receptor. Selected peptide effectively inhibited binding of GM-CSF to its receptor as demonstrated with different methods. We selected the non-cytotoxic peptides that potently blocked microglia-dependent glioma invasion in cell co-cultures. Blocking GM-CSF-receptor signaling pathway with a neutralizing antibody against a GM-CSF receptor also inhibited microglia-dependent invasion of glioma cells. Altogether, our results demonstrate that glioma-derived GM-CSF supports pro-tumorigenic polarization of microglia turning them into cells that facilitate glioma growth and shape the immune microenvironment. The study was supported by grant 2014/15/B/NZ3/04704 from The National Science Centre, Poland.
SCIDOT-32. NEUROSURGICAL DELIVERY OF THE POLY ADP RIBOSE POLYMERASE-1 INHIBITOR OLAPARIB FROM A THERMO-RESPONSIVE BIODEGRADABLE PASTE POTENTIATES RADIOTHERAPY AND PROLONGS SURVIVAL IN HIGH-GRADE GLIOMA
Authors: Smith Stuart , Serra Riccardo , Rowlinson Jonathan , Gorelick Noah , Veal Gareth , Shakesheff Kevin , Brem Henry , Grundy Richard , Tyler Betty , Rahman Ruman
Published: November 2019

There has been considerable interest in repurposing the poly ADP ribose polymerase inhibitor and purported radiosensitiser olaparib (Lynparza), with a recent dose escalation study of olaparib plus temozolomide in recurrent GBM showing good tolerance (Fulton et al 2018). Due to systemic therapy-associated caveats such as dose-limiting toxicities and blood-brain-barrier penetration, here we assess localised post-surgical delivery of olaparib from our previously developed poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) (PLGA/PEG) thermo-sensitive biodegradable paste. Metabolic and clonogenic assays revealed impaired proliferation and clonal growth respectively, upon acute exposure of high-grade glioma cells to olaparib (3–5µM), an effect dramatically potentiated with 3Gy radiation. Flow cytometry of Annexin V+/Propidium iodide+ rodent and human high-grade glioma cells, revealed a significant cell proportion increase at late stage apoptosis when exposed to 2–3µM olaparib and 3Gy radiation (relative to untreated, olaparib alone or radiation alone). A high-grade glioma orthotopic allograft study is ongoing where we already observe a significant overall survival benefit of locally-delivered 10% and 20% w/w (drug:polymer ratio) olaparib via PLGA/PEG paste post-surgery with adjuvant radiotherapy, compared to surgery/oral temozolomide/radiotherapy (GBM standard-of-care) and surgery/systemic olaparib (120 days vs. 44 vs 30 respectively). A more pronounced survival benefit, as determined by the total number of long-term surviving animals, was observed with combined PLGA/PEG/olaparib/temozolomide/radiotherapy or PLGA/PEG/olaparib/etoposide/radiotherapy. RNAseq data from 10 GBM patients show significantly elevated levels of apoptosis-inducing factor-1 in 5-aminolevulinic acid (5ALA)+ fluorescence–activated cell sorted populations (i.e. purified tumour cells from the invasive margin), relative to 5ALA- cells, confirming PARP-1 activity in infiltrative tumour cells. Collectively our data supports a clinical rationale for localised olaparib delivery with adjuvant radiotherapy.
SCIDOT-34. BRAIN INJURY SIGNALS SYSTEMIC IMMUNOSUPPRESSION THROUGH THYMIC INVOLUTION
Authors: Ayasoufi Katayoun , K Pfaller Christian , H Khadka Roman , Jin Fang , Zheng Jiaying , R Schuelke Matthew , Evgin Laura , J Hansen Michael , T Himes Benjamin , E Fain Cori , P Tritz Zachariah , N Goddery Emma , T Yokanovich Lila , R Pease Larry , G Vile Richard , J Johnson Aaron
Published: November 2019

Systemic immunosuppression following neurological insults including stroke, traumatic brain injury, and glioblastoma (GBM) causes mortality and leads to failure of immune-modulating therapies. Exact immunological nature and the underlying mechanisms of this immunosuppression are unknown. Our goal was to define effects of neurological insults given exclusively to the brain on the thymus. The thymus is the primary immune organ responsible for T-cell development and maintenance both in children and in adults. We evaluated the brain-thymus communication using the following neurological insults: physical injury, CNS viral infection, sterile injury, tumor implantation, and seizures. All insults resulted in significant thymic involution that was reversible upon clearance of the insult. Thymic involution did not occur following similar peripheral insults. We next demonstrated that the GL261 model of GBM recapitulates hallmark features of peripheral immunosuppression observed in GBM patients including low CD4 T-cell counts. Thus, we aimed to further study the immunosuppression affecting the thymus in this clinically relevant model. Principle component analysis following RNA-sequencing of thymi from naïve and glioma-bearing mice revealed unbiased separation of the groups suggesting that the thymus is directly affected by a brain tumor. To determine the extent to which thymic involution was caused by a soluble factor we employed parabiosis. We demonstrated that thymic involution was transferable from glioma-bearing to non-tumor-bearing parabionts. Similarly, serum taken from GL261 glioma-bearing mice potently inhibited proliferation of T-cells in vitro. Together our data demonstrate that CNS-specific insults, regardless of nature, cause immunosuppression by prompting thymic involution through circulating factors. This accounts at least partially for immune deficiencies observed following neurological injuries. Identification of this suppressive factor is crucial in designing future therapeutics for GBM patients, and patients with other acute and chronic neurological trauma.
SCIDOT-36. PREDICTIVE CED INFUSION VOLUMES FOR SURGICAL PLANNING AND INFUSION REGIME STRATEGIES
Authors: Killick-Cole Clare , Woolley Max , Johnson David , Lewis Owen , Skinner Paul , Bienemann Alison , Gill Steven
Published: November 2019

Previous research and clinical trials have highlighted the utility of convection-enhanced delivery (CED) to directly administer therapeutics to the brain. This method bypasses the blood-brain barrier, which is a major obstacle in systemic drug delivery. The Renishaw Neuroinfuse™ recessed step catheter has been developed to utilise a mechanism we have termed “controlled reflux” to maximise distribution within brain targets, whereby the infusate tracks to a flow inhibiting feature. Once in contact with this feature, the flow pathway is initiated radially along the step region, facilitating a low-pressure infusion profile that minimises fast flow-rate tissue damage at the catheter tip whilst maximising coverage. This can be demonstrated through in vitro studies, in vivo preclinical work and humanitarian cases treating DIPG. The controlled reflux mechanism provides a level of infusion prediction, which can be used for catheter placement planning in order to optimize infusion distribution within a chosen target area. The Neuroinfuse™ catheter is delivered through an implantable guide tube whereby the guide tube and the catheter lengths are cut to provide bespoke features within the controlled reflux zone. By manipulating catheter step lengths this way, catheters can be designed to achieve target distribution volumes within an individual’s unique brain anatomy. Here we will present data demonstrating the utility of the acute catheter system, and its additional use as a modular component of the chronic drug delivery system. This modularisation strategy provides attributes for catheter placement and infusion distribution planning that spans across multiple indications for neuro-oncology and neurodegenerative diseases.
SCIDOT-41. NANOTHERAPEUTIC TARGETING OF TUMOR ENDOTHELIUM FOR ENHANCING DRUG DELIVERY PAST THE BLOOD-BRAIN BARRIER
Authors: Kiguchi Hiroto , Manzari Mandana , Vaynshteyn Jake , Gerwin Jeffrey , Tylawsky Daniel , Li Na , Shah Janki , Shamay Yosi , Greenblatt Matthew , Heller Daniel , Praveen Raju G
Published: November 2019

OBJECTIVE

The Sonic Hedgehog (SHH) medulloblastoma subgroup accounts for ~25% of all cases and has an intermediate prognosis. Current conventional therapies result in devastating morbidities including intellectual disability and secondary malignancies. Although molecularly targeted agents that inhibit the SHH pathway have demonstrated clinical efficacy, recent studies have shown on-target secondary toxicities on bone development suggesting new therapeutic approaches are needed.

METHODS

We investigated the efficacy of the SHH pathway inhibitor, Vismodegib packaged in a fucoidan-based nanoparticle (Fi-Vis) that targets P-selectin, a protein overexpressed on vascular endothelial cells and induced by low-dose ionizing radiation (XRT) in a time- and dose-dependent manner. This P-selectin targeting nanoparticle drug delivery system shows selectivity toward tumor vasculature and not normal brain vasculature in a genetic SHH medulloblastoma mouse model as assessed by ex vivo infrared imaging and two-photon intravital imaging.

RESULTS

Quantitative RT-PCR analysis of SHH medulloblastoma tissue following single dose XRT and Fi-Vis treatment (10mg/kg) showed a synergistic inhibition of Gli1 expression (>90% target inhibition). Furthermore, we demonstrate that very low dose XRT (0.25Gy) can induce P-selectin expression specifically within MB tumor vasculature and synergize with low dose Fi-Vis (10mg/kg) to significantly enhance mouse survival (p<0.01) when compared to radiation or Fi-Vis alone. Furthermore, assessment of bone toxicity using micro-CT and histological analysis following Fi-Vis administration in postnatal (P10) mice shows no bone toxicity when compared to free Vismodegib. Finally, in vitro studies using mouse brain endothelial cells suggest at least in part a caveolin-1 mediated transcytosis mechanism of crossing the endothelial blood-brain barrier.

CONCLUSIONS

These data suggest applicability of combined XRT and tumor vasculature-targeted nanotherapeutic dose de-escalation strategies for SHH medulloblastoma with implications for other pediatric and adult brain tumors.
SCIDOT-42. FT-2102 – A POTENT AND SELECTIVE BRAIN PENETRANT INHIBITOR OF MUTANT ISOCITRATE DEHYDROGENASE
Authors: Ribadeneira Maria , Guichard Sylvie , Yao Lili , Toms Angela , Forsyth Sanjeev , Thomson Blythe , Ehrlich Paul
Published: November 2019

BACKGROUND

Iocitrate dehydrogenase mutations (mIDH1) are present in >70% of patients with Grade II/III gliomas resulting in production and accumulation of (R)-2-hydroxyglutarate (2-HG) causing DNA hypermethylation and promoting tumorigenesis. This abstract summarizes the structure-based design of FT-2102, a potent and selective inhibitor of mutated IDH1-R132 with brain distribution (Kpuu) that is in context of minimal effective concentrations required in brain to modulate 2-HG.

METHODS

The crystal structure of mutated IDH1 in complex with FT-2102 and NADPH cofactor (2.1A resolution) was determined via sitting-drop vapour-diffusion set-ups. HCT116/IDH1 R132H were implanted in Balb/c nude mice and FT-2102 was administered orally twice daily. FT-2102 and 2-HG levels in plasma and xenografts were determined by LC/MS. In silico and in vitro models were used to determine the extent of brain distribution and ex-vivo rat data was generated to validate the projected distribution into brain tissue (Kpuu).

RESULTS

In tumor Xenograft (HCT116/IDH1-R132H), FT-2102 inhibits tumor 2-HG production with an IC50 of 24nM which is consistent with its in vitro IC50 of 18nM. FT-2102 unbound plasma concentrations of 256nM in xenografted mice were found to achieve 90% reduction of 2-HG in tumor. Rat data showed that FT-2102 partitions into brain with a Kpuu of 0.45. Based on these data, the concentration of FT-2102 in brain to significantly reduce 2HG is predicted to be 115nM. Recent publications (Natsume, et al, ASCO19) propose 90% reduction of 2-HG (90%) is associated with tumor reduction in the brain.

CONCLUSION

The structure-based design of FT-2102 has facilitated CNS penetration in animal models and is undergoing evaluation in ongoing clinical trials including patients with CNS based IDH1m tumors (NCT: 03684811).
ANGI-07. NOVEL FUSION GENE PTPRZ1-MET PROMOTES GLIOMAS ANGIOGENESIS BY UP-REGULATING EXOCRINE PROTEIN IGF2BP3
Authors: Liu Yanwei , Qiu Xiaoguang , Jiang Tao
Published: November 2019

We previously reported a novel fusion gene PTPRZ1-MET in 15% of secondary GBM (sGBM). Subsequent studies showed that ZM fusion indicates a significantly worse prognosis and promotes glioma progression by increasing MET activity. We have demonstrated hyper-activation of MAPK and STAT3 signaling and elevated angiogenesis activities in patients and subcutaneous tumors with ZM fusion. However, the angiogenesis mechanism regulated by ZM is still unclear. In this study, 66 up-regulated and 66 down-regulated genes were identified on 8 sGBMs with ZM fusion comparing gene expression with 135 negative sGBMs (fold-change >2.5 & p.value < 0.05). ZM-harboring U87 MG xenograft models were conducted and RNA sequencing was performed in 3 subcutaneous tumors with ZM-harboring U87 MG and 3 negative control. 384 up-regulated and 698 down-regulated genes were identified on 3 ZM-harboring samples comparing gene expression with 3 negative control samples (fold-change >2.5 & p.value < 0.05. Three subcutaneous tumors with ZM-harboring U87 MG were treated by a MET kinase inhibitor, PLB-1001. Finally, the expression of 13 up-regulated gene decreased and 10 down-regulated genes increased after treatment by PLB-1001. We overlapped the candidate genes between patient samples and subcutaneous tumors and 5 up-regulated and 4 down-regulated genes was appeared and most associated with ZM fusion. Prognostic analysis of 9 candidate genes on sGBM revealed that a higher expression of IGF2BP3 indicates a worse prognosis. In further study, we found that IGF2BP3 can be secreted out of the gliomas stem cells (GSCs) and promote proliferation of vascular endothelial cells and the expression of CD31. IGF2BP3 siRNA can block this pathway and inhibit the angiogenesis. Conclusion, our study demonstrated a new pathway promoting angiogenesis in gliomas. But the regulating mechanism between ZM fusion gene and IGF2BP3 deserves to do further research.
SCIDOT-44. CREATING CAUSAL CAPABILITIES IN FUNCTIONAL BRAIN MAPPING USING A CED APPROACH
Authors: Block Walter , Birns Rasmus , Olsen Miles , Hurley Samuel , Brodsky Ethan , Rajala Abigail , Filla Caitlynn , McMillan Alan , Alexander Andrew , Jenison Rick , Populin Luis
Published: November 2019

INTRODUCTION

The spatial and temporal resolution limits of functional MRI (fMRI) brain mapping provide primarily correlative information on brain connectivity. Determining how one region causally modulates and mediates activity in other regions remains difficult with fMRI. We demonstrate a simple means to add causality in resting state functional connectivity MRI (rs-fcMRI) using techniques developed first for convection-enhanced delivery (CED) of therapeutics. Here we use CED to guide and monitor pharmacologic alteration of a local brain region in anaesthetized Rhesus monkeys while monitoring rs-fcMRI signal changes.

METHODS

Pre-surgical MRI was used to determine skull locations for craniotomies for installation of NavigusTMbrain ports in two untrained monkeys slated for euthanasia. The ports were aligned in real–time to provide trajectories aimed at the central nucleus of the amygdala (CeA). Fused silica catheters were then inserted into the CeA where 24 mg of muscimol (inhibitory agent) was infused in 24 ml of buffered solution under pressure over 12 minutes, first on the right side and then on the left side. rs-fcMRI studies were done for 45 minutes before and after the unilateral infusion and then after the bilateral infusion.

RESULTS

Catheters were successfully aligned and inserted into the CeA targets with sub-mm accuracy. T2-weighted imaging detected the enhanced T2 from the infusion’s buffer. Pre-infusion rs-fcMRI provides results consistent with prior studies, which have shown that the CeA is most strongly connected to the contralateral CeA. This connectivity was significantly reduced following both unilateral and bilateral injections of muscimol into the CeA, demonstrating the effectiveness of the muscimol infusions. Conditional Grainger Causality (CGC) analysis shows unexpected new connectivity after the unilateral infusion. Upon the bilateral infusion, global effective connectivity in the region is reduced.

CONCLUSION

Expected and unexpected changes in resting state functional connectivity resulted from unilateral and bilateral infusions of inhibitory agents.
SCIDOT-48. EVALUATING THE THERAPEUTIC EFFICACY AND CONVECTION ENHANCED DELIVERY (CED) TOXICITY ANALYSIS OF CDK4/6 INHIBITOR PALBOCICLIB FOR DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)
Authors: Lee Dennis , Maachani Uday , Adeuyan Oluwaseyi , Guadix Sergio , Souweidane Mark
Published: November 2019

DIPG is a devastating, aggressive brain tumor of childhood. No chemotherapeutic agent has so far shown significant clinical efficacy and focal radiation therapy provides only temporary relief. Recent studies on the genomic aberrations of pediatric gliomas have shown that a subset of these tumors harbor focal gains in proteins of the cyclin-dependent kinase (CDK) 4/6 cell cycle pathway. H3.3K27M mutation, associated with >80% of DIPGs, has also been associated with epigenetic silencing of p16 tumor suppressor, an important effector in regulating CDK4/6 pathway. In this study, we characterized and confirmed through immunoblot analysis that proteins involved in CDK 4/6 pathway, including Rb1, are intact in multiple patient derived DIPG (SU-DIPG-IV, SU-DIPG-XIII, SU-DIPG-XVIII, SF8628) and wild type (SF9428) cell lines. Expression of p16 was decreased or undetectable in DIPG cells compared to normal astrocytes. In addition, pharmacologic inhibition of CDK4/6 with palbociclib showed dose dependent reduction in DIPG cell proliferation with IC50 ranging from 5.42uM to 21.35uM between different cell lines. However, major problems of palbociclib are that it does not readily cross the blood-brain-barrier (BBB) and has major systematic toxicities, such as myelosuppression, which limits oral dosing. One solution to overcome the BBB is convection enhanced delivery (CED) which is a form of local delivery that bypasses the BBB by placement of small diameter catheters directly into the brain tumor. With this approach, high regional drug concentration can be achieved with negligible systemic toxicity. In this study, we also observed no significant short- or long-term neurotoxicity of palbociclib delivered via CED in a mouse model. We hypothesize that the CDK4/6 cell cycle pathway has an important role in DIPG tumorigenesis and progression and that existing therapies targeting these pathways, which are already in clinical use for other cancers, can be rapidly repurposed for the treatment of DIPG through CED.
SCIDOT-52. IN SITU DELIVERY OF TUMOR TREATING FIELDS THERAPY IN GLIOBLASTOMA PATIENTS
Authors: Arle Jeffrey , Wong Eric , Korshoej Anders , Dokos Socrates , Bomzon Ze’ev , Carlson Kristen
Published: November 2019

The efficacy of Tumor-Treating Fields (TTFields) rests on the result of a large-scale clinical trial that demonstrated an increase in the survival of newly diagnosed glioblastoma patients when combined with temozolomide chemotherapy. Overall survival now extends to over 60 months in some of our patients when dexamethasone, which we suspected of interference with TTFields effects, is replaced with celecoxib to control tumor-associated inflammation. The transcranial method of delivering TTFields has not changed in light of ongoing advances in deep brain stimulation (DBS) and transcranial electric stimulation (TES), notably that the resistivity of the skull is the principle obstacle to placing therapeutic electric field strength of 2 V/cm into target tumor sites and variation in skull thickness is the main difference in TES efficiency across individuals. Realistic human head finite element modeling (FEM) predicted that surgical craniectomy beneath TTFields’ electrodes would enhance field strength at target tumor sites. Here we show that 2 V/cm can be reliably delivered to tumor sites using minimally-invasive DBS cylindrical leads or ribbon electrode arrays, pre- or post-resection. Two objections arise to the in situ method: 1) Will TTFields stimulate axons in situ? 2) Will field strength exceed safety limits for cell damage? Neural stimulation modeling and experiments show that TTFields’ frequency of 200 kHz, 1–3 orders of magnitude higher than ion channel time constants, is too high to stimulate them. Furthermore, 2 V/cm is well below cell damage limits of 700 V/mm. Thus we propose a new delivery method to improve tumor control in glioblastoma patients and to provide valuable information on TTFields’ effects via cell studies using in situ electric fields at 200 kHz.
RARE-50. PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMA – OUTCOMES IN THE ‘HAEMATOLOGY ERA’
Authors: Kumar Siddhant , Islim Abdurrahman , Smith Jeffrey , Haylock Brian , Shenoy Aditya , Husband David , Mills Samantha , Brodbelt Andrew , Chavredakis Emmanuel , Lawson David , Jenkinson Michael
Published: November 2019

BACKGROUND

Primary CNS lymphoma (PCNSL) requires a biopsy for diagnosis. Administration of corticosteroids can lead to inconclusive results and delay diagnosis. The aim of this study was to compare outcomes of patients treated under haematology compared to radiation oncologists.

METHODS

Retrospective case review of patients treated under radiation oncology (2006–2010) and haematology (2011–2016).

RESULTS

121 cases were identified (median age 63 years; range 19–84). Median WHO performance status (PS) was 1. Fourteen patients (11.6%) required repeat biopsy. 10 patients were managed palliatively due to poor PS. 67 cases were managed under haematology. Median symptom duration was 28 days (range 2–540). Median time from MRI to diagnosis was 18 days (range 6–232). 66 patients received chemotherapy, 1 received radiotherapy. Median overall survival (OS) was 8 months (95%CI:0.7–15.3), 5-year OS was 22.4%. 44 cases were managed under radiation oncology. Median symptom duration was 28 days (range 2–365). Median time from MRI to diagnosis was 16 days (range 6–309). 34 patients received radiotherapy first-line, 10 received chemotherapy. Median OS was 7 months (95%CI:0–21.5), 5-year OS was 15.9%. Multivariate analysis demonstrated PS (HR 2.02 (95%CI: 1.08–3.76)) and symptom duration (HR 0.63 (95%CI: 0.41–0.96)) to be significant prognostic indicators for OS.

CONCLUSION

The outcomes from the ‘haematology era’ are similar to those achieved by radiation oncologists. Delay in diagnosis leads to worse outcomes and highlights the ongoing need to streamline the patient pathway to improve outcomes.
ANGI-11. SEX DIFFERENCES IN IMAGING-BASED ASSESSMENT OF GLIOBLASTOMA INVASION
Authors: Christine Massey Susan , Hawkins-Daarud Andrea , Jackson Pamela , Grove Rebecca , Bakken Katrina , He Lihong , Mladek Ann , Stokes Ashley , Gonzalez Ashlyn , Nespodzany Ashley , Eschbacher Jenny , Baxter Leslie , Smith Kris , Nakaji Peter , McGee Samuel , Bendok Bernard , Burns Terence , Sarkaria Jann , Hu Leland , Swanson Kristin
Published: November 2019

INTRODUCTION

Neuroimaging dogma for glioblastoma asserts that hyperintensity on T1Gd MRI reveals the bulk of the tumor, while T2/FLAIR signal indicates edema. However, it is unclear whether this edema results from immune response or increased tumor cells. Further, one significant driver of the known sex differences in glioblastoma may be differences in immune response, due to the X-linkage of many immune genes. Based on this, we hypothesized that assumptions regarding tumor cellularity in T2/FLAIR images should be tailored to the biological sex of the patient.

METHODS

Using a retrospective cohort of 18 primary glioblastoma patients receiving multiple image-localized biopsies (82 total) and standard MRI, we assessed: distance of biopsy from T1Gd and T2 areas; a pathologist’s score of percent tumor cell density; and an imaging-based invasion metric, D/ρ. This metric is derived from the biomathematical Proliferation-Invasion model of glioma growth, which features two parameters, net growth rate (ρ) and net invasion rate (D). Their ratio D/ρ is related to degree of invasion, and is estimated from volumetric measurements of MRI abnormalities. Additionally, 25 patient-derived xenograft models implanted in females were grown until moribund, at which point brains were excised and stained for DAPI (to show all cells) and Lamin (to highlight tumor cells). Image processing of lamin-stained sections defines contours of intensity correlating with cell density.

RESULTS

Outside both the T1Gd and T2 region, male patient biopsies had higher tumor cell densities than females. Males also tended to have higher invasion metrics. Although each set derived from different patients, preclinical metrics of invasion were positively correlated with clinical invasion in females but negatively correlated in males.

CONCLUSION

Our preliminary finding that cell distribution patterns correlate with imaging metrics differently between the sexes supports the hypothesis that the degree of tumor cell density represented on certain MRI sequences may be sex-specific.
CBMT-01. ALANINE FUELS ENERGY METABOLISM OF GLIOBLASTOMA CELLS
Authors: Ijare Omkar , Baskin David , Pichumani Kumar
Published: November 2019

Despite available aggressive treatment options, glioblastoma multiforme (GBM) has a median survival of 16 months indicating an urgent unmet need to develop new therapeutic strategies. Earlier, we have demonstrated that both glucose and acetate are the two major nutrients leading to synthesis of approximately ~60% acetyl-CoA in the brain tumors. Therefore, there must be other nutrients that may contribute to bioenergetic needs of highly proliferative GBM cells. Alanine is one of the non-essential amino acids (NEAA) that is constantly produced in cancer cells through Warburg glycolysis and its role in cancer metabolism is not well understood. Recently, it has been shown that alanine produced by pancreatic stellar cells contributed to the energy metabolism in pancreatic cancer cells. However, it is not known whether GBM can use alanine as an energy source. Here, we test whether GBM cells have the ability to metabolize alanine as a fuel to meet its increased energy requirements. Patient-derived GBM cells were cultured with 2.0 mM [3-13C]alanine for the final 24 hours, harvested in 50% methanol, snap-frozen in liquid N2, freeze-thaw cycle 3 times and lysates were stored at -80 °C. Derivatized material from the frozen lysates were used for GC-MS analysis to determine carbon mass isotopomer distribution (MID) of various glycolytic and TCA cycle intermediates. Our results indicated that [3-13C]alanine entered the GBM cells and produced [3-13C]lactate via pyruvate. Also, alanine-derived [3-13C]pyruvate led to the generation of [2-13C]acetyl-CoA, which entered TCA cycle and produced M+1 13C isotopomers of citrate, glutamate, malate and aspartate. MID showed the following 13C enrichment (M+1) values: citrate, 6.9 % ± 0.3%; glutamate, 4.4% ± 0.3%; malate, 2.1% ± 0.6%; 2.1% ± 0.5%. This preliminary data shows that GBM cells are capable of utilizing alanine to generate energy and produce precursors for biomolecular synthesis.
CBMT-02. UP-REGULATION OF Γ-GLUTAMYL-TRANSFERASE CAN BE USED TO IMAGE GLIOBLASTOMA USING HYPERPOLARIZED Γ-GLUTAMYL-[1-13C]GLYCINE MRS
Authors: Batsios Georgios , Najac Chloe , Cao Peng , Viswanath Pavithra , Subramani Elavarasan , Saito Yutaro , Marie Gillespie Anne , Yoshihara Hikari , Larson Peder , Sando Shinsuke , Ronen Sabrina
Published: November 2019

γ-glutamyl-transferase (GGT) is a key enzyme in the γ-glutamyl cycle, which regulates glutathione homeostasis. The enzyme is localized on the outer cell membrane and cleaves glutathione to glutamate and cysteinylglycine. As such, it facilitates uptake of the amino acids essential for intracellular synthesis of glutathione (GSH), which is the major thiol anti-oxidant. GGT is upregulated in glioblastoma, but remains low in normal brain. It is therefore an attractive molecular imaging target for specific detection of glioblastoma. The goal of our study was therefore to assess for the first time the value of hyperpolarized (HP) γ-glutamyl-[1-13C]glycine (γ-Glu-[1-13C]Gly) for imaging glioblastoma in orthotopic tumor-bearing rats. Athymic nude rats with U87 glioblastoma tumors or tumor-free controls were investigated. First, we confirmed that GGT expression was significantly higher in U87 tumors compared to normal rat brain tissue. GSH levels were also higher. Imaging studies were then performed by injecting HP γ-Glu-[1-13C]Gly and acquiring dynamic 13C MR spectra using a flyback spectral-spatial slab sequence on a preclinical Bruker 3T MR system. The dynamic data were analyzed by measuring the signal-to-noise (SNR) ratios of the substrate (γ-Glu-[1-13C]Gly) and the product ([1-13C]Glycine). Comparison of control and tumor-bearing rats showed no statistically significant difference in the SNR of the substrate. In contrast, the SNR of the product demonstrated a significantly higher level of HP [1-13C]Glycine in the tumor-bearing rats compared to controls. Consistent with the higher levels of HP [1-13C]Glycine, the [1-13C]Gly-to-γ-Glu-[1-13C]Glycine ratio was also significantly higher in tumor-bearing animals relative to controls (0.046±0.004 vs 0.021±0.008 respectively; p=0.03). Further studies are needed to assess the generality of our findings. Nonetheless, this study demonstrates for the first time the feasibility of using γ-Glu-[1-13C]Gly to monitor GGT activity and thus could serve as a new approach for monitoring the presence of tumor.
CBMT-03. EVALUATION OF PET TRACERS TO DIFFERENTIATE IDH1 MUTANT GBM
Authors: Molotkov Andrei , Mela Angeliki , Canoll Peter D , Mintz Akiva
Published: November 2019

OBJECTIVE

PET/CT offers the unique potential to noninvasively evaluate biomarker expression and aberrant metabolism. 18F-FDG has driven PET/CT to the forefront of cancer imaging, as altered glucose metabolism is a hallmark of oncogenesis. However, 18F-FDG is suboptimal for GBM due to high physiologic uptake in normal brain. The development of alternative tracers has reignited the field of PET/CT in GBM and offers hope for diagnosis and molecular staging in GBM. We hypothesize that fundamental differences in metabolism and oncogene expression present in IDH1 mutatant gliomas can be shown using PET imaging, as has been suggested in some correlative clinical studies. Our objective was therefore to establish a causal link between IDH1 mutation in GBM and uptake of targeted PET tracers in a unique proneural GBM transgenic model characterized by p53, IDH1 mutations and PDGF expression.

METHODS

We examined the uptake of 3 blood-brain-barrier (BBB) penetrant tracers that have been used in GBM: (a) 18F-FDG, a surrogate for increased glycolysis; (b) 18F-Fluciclovine, an amino acid derivative transported into cells through the energy-independent L-type amino acid transporter (LAT) system and is approved by the FDA for prostate cancer; and (c) 11C-ER176, a tracer that binds the TSPO receptor that is generally expressed on activated microglia as well as GBM.

RESULTS

We did not observe significant differences in 18F-FDG uptake between wt and IDH mutant GBM cells. However, we found that IDH mutant GBM cells demonstrated significantly increased 18F-Fluciclovine (47%) and 11C-ER176 (53%) versus IDH wt cells.

CONCLUSION

We have established a causal link between IDH mutation status and uptake of (a) 18F-Fluciclovine, a promising FDA approved PET tracer and (b) 11C-ER176, a second generation TSPO ligand. Thus, we are performing further studies in orthotopic syngeneic GBM models to determine if PET imaging can non-invasively demonstrate molecular characterization and therapeutic stratification in glioma.