bluuebunny/crossref_metadata_2025 huggingface dataset:
SCIDOT-19. A MECHANICALLY-ENGINEERED SPRAY TO INCREASE BRAIN PENETRATION OF CHEMOTHERAPEUTIC NANOPARTICLES IN THE TREATMENT OF HIGH-GRADE GLIOMAS
Authors: McCrorie Phoebe , Taresco Vincenzo , Xu Zeyuan , Ritchie Alison , A Clarke Philip , Marlow Maria , 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-28. TARGETED NANOPARTICLES FOR IMPROVED DRUG DELIVERY TO MEDULLOBLASTOMA
Authors: Straehla Joelle P , Boehnke Natalie , Dacoba Tamara G , Hammond Paula T
Published: November 2019

Platinum-based agents remain a key component of therapy for children with medulloblastoma, despite significant systemic side effects and only modest blood-brain barrier (BBB) penetration. Cisplatin has a cerebrospinal fluid-to-plasma ratio <5% and dose-limiting side effects of nephrotoxicity, ototoxicity, and myelosuppression. Improving delivery of cisplatin across the BBB and selectively accumulating in tumors could improve its therapeutic index. To this end, we are leveraging chemical engineering techniques to rationally design cisplatin nanoparticles (NPs) to cross the BBB and preferentially enter medulloblastoma tumor cells. Using the layer-by-layer (LbL) platform to ‘wrap’ polyelectrolytes around a NP core by iterative electrostatic adsorption, we screened six negatively charged polypeptide and polysaccharide outer layers in medulloblastoma cell lines. Poly-L-aspartic acid (PLD) layered NPs had significant accumulation in tumor cells after 24 hours incubation, with an uptake index of 18±4 over unlayered control NPs. Next, we generated propargyl-functionalized PLD and used click chemistry to covalently conjugate the BBB shuttle ligands glutathione, angiopep-2, and transferrin, which have been shown to mediate transcytosis across brain endothelial cells. PLD layered NPs functionalized with angiopep-2 and transferrin had enhanced uptake in medulloblastoma tumor cells and NPs functionalized with glutathione were non-inferior to PLD layered NPs. After incubation with endothelial cells in vitro, all three BBB shuttle ligands enhanced uptake of PLD layered NPs over unlayered and non-functionalized control NPs. We then incorporated cisplatin into the nanoparticle core of this platform. Cisplatin-loaded NPs with PLD layering and ligand functionalization were more effective than free cisplatin as measured by IC50 over 72 hours in culture, and led to faster apoptosis as assessed by flow cytometry with annexin V and propidium iodide staining. In summary, functionalized nanoparticles are a promising platform to modulate drug delivery to medulloblastoma. In vivo studies using an orthotopic xenograft model are underway to investigate biodistribution, efficacy, and toxicity.
ANGI-06. FUNCTION OF FORMIN-LIKE 1 (FMNL1) IN GLIOBLASTOMA MULTIFORME
Authors: Higa Nayuta , Shinsato Yoshinari , Takajyo Tomoko , Yonezawa Hajime , Uchida Hiroyuki , Furukawa Tatsuhiko , Yoshimoto Koji
Published: November 2019

INTRODUCTION

Glioblastoma multiforme is the most common primary malignant brain tumour in adults. It is characterised by rapid proliferation, aggressive migration, and invasion into normal brain tissue. Formin proteins have been implicated in cancer progression, invasion, and migration. However, the role of FMNL1 in cancer remains unclear. We are the first to investigate FMNL1 in GBM.

METHODS

Clinical specimens were obtained from tumours surgically removed and pathologically confirmed as GBM from 217 GBM patients treated from 2000 to 2015 at the Department of Neurosurgery, Kagoshima University Hospital. We studied the expression of FMNL1 in glioblastoma samples by immunohistochemistry to analyse the correlation between FMNL1 expression, clinicopathologic variables, and patient survival. Migration and invasion assays were used to verify the effect of FMNL1 on glioblastoma cell lines. Microarray data were downloaded from TCGA and analysed using Gene Set Enrichment Analysis (GSEA).

RESULTS

FMNL1 was found to be a predictor of poor prognosis in a cohort of 217 cases (P < 0.001). GSEA showed that upregulation and downregulation of FMNL1 were associated with mesenchymal and proneural markers, respectively. Contrarily, downregulation of FMNL1 suppressed migration and invasion of glioblastoma multiforme cells via DIAPH1 and GOLGA2, respectively. Downregulation of FMNL1 also suppressed assembly of actin fibres, induced morphological changes, and diminished filamentous actin.

CONCLUSION

Our studies show that abundant FMNL1 expression in GBM patients is correlated with an unfavourable prognosis. FMNL1 is a promising therapeutic target and a useful biomarker for GBM progression.
SCIDOT-37. ASSESSING CEREBROSPINAL FLUID FLOW DYNAMICS IN PEDIATRIC PATIENTS WITH CENTRAL NERVOUS SYSTEM TUMORS
Authors: Kramer Kim , Donzellie Maria , Nwora Emmanuela , Pandit-Taskar Neeta
Published: November 2019

BACKGROUND

The incidence of abnormal CSF flow dynamics in the pediatric population with CNS tumors prior to intraventricular therapy has not been described.

METHODS

We performed a single-institution, retrospective review of patients with primary or metastatic CNS tumors treated between 2003–2018 (15 years).. Patients underwent 111-indium diethylene triamine pentaacetic acid injection into the CSF intraventricular space followed by nuclear medicine imaging at 90 minutes, 4, 24, and 48 hours (if required). CSF flow was classified as normal, delayed, asymmetric or obstructed.

RESULTS

278 CSF flow studies were performed in 224 patients, 202(90%) <18 years of age. 116(52%) patients had metastatic CNS neuroblastoma, 57(25%) had medulloblastoma, and 51(23%) had other CNS histologies. Of the 278 studies, 237(85%) were normal, 9(3%) required neurosurgical intervention, 25(9%) were delayed, and 7(3%) were asymmetric.

CONCLUSIONS

Abnormal CSF flow and necessity of neurosurgical intervention must be considered when attempting to ensure appropriate intraventricular therapy in the pediatric population.
SCIDOT-47. EFFECT OF ulRFE COGNATES EMULATING BIOACTIVE SUBSTANCES ON ANIMAL BEHAVIOR
Authors: Figueroa Xavier , Butters Mike , Donnell Scott
Published: November 2019

BACKGROUND

The EMulate Therapeutics Voyager system produces a magnetic field obtained from the magnetic fluctuations produced by molecules in solution. These recordings, ultra-low radio frequency energy (ulRFE®) cognates, are intended to emulate the effects of the molecule.

METHODS

Mice were treated with cognates for up to 120 min on the first day, then 24 h/day for the next 15 days.

RESULTS

All ulRFE cognates were well tolerated. Body weights remained stable. Animals exposed to signals derived from melatonin, THC (tetrahydrocannabinol), scotch, and ethanol showed signs of mild hypo-activity, while cognates derived from CBD (cannabidiol), Everclear, nicotine, and white wine showed mild signs of somnolence. Caffeine exposure initially caused mild hyperactivity, which returned to normal after the 120 minutes. The espresso cognate induced signs of mild hyperactivity during the initial 20-minute exposure. After 40 minutes, mild head convulsions and normal activity levels were noted. After 120 minutes, signs of hypoactivity were seen. Animals exposed to caffeine ulRFE showed signs of mild hyperactivity for the duration of the 15-day exposure, and animals exposed to nicotine, melatonin, THC, CBD, Everclear, scotch, and white wine cognates experienced mild hypo-activity. Animals exposed to espresso or 100% ethanol ulRFE remained normal during the 15-day exposure.

CONCLUSIONS

Mice displayed altered behavior when exposed to the magnetic field produced by the cognates, which, at least in part, were consistent with some effects that would be anticipated for the molecules used to create the cognates. The ulRFE technology offers potential to emulate the effects of bioactive substances across the blood:brain barrier.
CBMT-07. BIOMARKERS OF AGGRESSIVENESS IN IDH MUTANT GLIOMA
Authors: Yamasaki Tomohiro , Lita Adrian , Dowdy Tyrone , Gilbert Mark , Larion Mioara
Published: November 2019

BACKGROUND

Gliomas with isocitrate dehydrogenase (IDH) mutations in adults evolve from lower-grade gliomas to secondary glioblastomas (GBM), a fatal disease with fast progression. IDH mutation occurs early in tumorigenesis, and persistently contribute to the reprograming of glucose, lipid and amino acid metabolism. This offer a plethora of potential biomarkers of progression. However, because it is extremely difficult to detect the distribution and transfer of metabolites changing in every moment in a single cell, the involvement of metabolites produced by mutant IDH in malignant progression remains understudied.

MATERIALS AND METHODS

Raman imaging spectroscopy, which can image chemical bonds and concentration of molecules at submicron spatial resolution, enables detection of spatiotemporal changes of metabolomes in live cells. We developed the software called Biomolecular Component Analysis (BCAbox) to deconvolute the recorded raw Raman spectra, leading to detection of unique spectral features of different classes of biomolecules.

RESULTS AND CONCLUSIONS

We applied Raman imaging spectroscopy to GBM cell lines that were transfected with IDH1 mutant gene. Our results indicated that lipid metabolism has a unique profile in IDH1 mutant gliomas. Subsequent mass spectrometry analysis of extracted organelle revealed the exact classes of lipids altered in the IDH mutant glioma and suggested biomarkers unique to IDH1 mutant. We will report our validation studies of the biomarkers in patient-derived IDH mutant glioma cell lines and patients derived-orthotopic xenograft mouse models with different degrees of aggressiveness and in matched primary versus recurrent gliomas. The results of the present study may provide novel insights into the discovery of metabolic biomarkers for the malignant progression in IDH mutant gliomas.
CBMT-14. THE DIELECTRIC PROPERTIES OF BRAIN TUMOR TISSUE
Authors: Proescholdt Martin , Haj Amer , Doenitz Christian , Brawanski Alexander , Bomzon Ze’ev , Sara Hershkovich Hadas
Published: November 2019

INTRODUCTION

Recently, tumor treating fields (TTFields) were established for the treatment of newly diagnosed GBM. One of the most crucial parameters defining the treatment efficacy of TTFields is the electric field intensity, which depends on the dielectric properties of the tumor tissue. In this study we determined the dielectric properties of brain tumors by analyzing resected tissue following a fast acquisition protocol. To account for the intratumoral heterogeneity, different regions of the tumor were analyzed separately.

METHODS

A cohort of 84 patients with tumors of different histology have been recruited. Tissue probes were acquired from the vital tumor area and perinecrotic compartment. The tissue was measured immediately to avoid artifacts. A fragment was dissected from each tissue sample and was placed into a cylindrical cell with a known diameter. The impedance was recorded at frequencies 20Hz-1MHz using a software specifically developed for this study, which controls the LCR meter. The measured impedance was translated into dielectric properties of the sample (conductivity and relative permittivity) based on the parallel plate model, the recorded complex impedance and the geometry of the samples. Each tissue probe was fixed, H&E stained and histologically analyzed.

RESULTS

We found significant differences between the conductivity of different types of tumors with meningiomas showing the lowest conductivity (mean conductivity [S/m]: 0.193; range: 0.327 – 0.113) and GBM tissue exhibiting the highest conductivity values (mean conductivity [S/m]: 0.402; range: 0.893 – 0.157). Consistently, the perinecrotic areas displayed lower conductivity values compared to the solid tumor compartments. Also, we found a significant intratumoral heterogeneity in tumors of one specific histological diagnosis.

CONCLUSION

The dielectric properties of intracranial tumors appear to be depending on histological class and malignancy grade and show significant intratumoral heterogeneity. These results may allow a more precise modelling of electric field intensity distribution within the tumor.
CBMT-21. TERT PROMOTER-MUTANT GLIOBLASTOMAS EXHIBIT DEPENDENCY ON TELOMERASE
Authors: Aquilanti Elisa , Baird Duncan , Watson Jacqueline , Meyerson Matthew
Published: November 2019

TERT promoter mutations are among the most common somatic alterations in cancer and they occur in about 80% of IDH-wildtype glioblastomas. TERT promoter mutations were found to reactivate telomerase by providing a novel binding site for the GABP transcription factor. While the effects of telomerase ablation are well understood in mice and somatic human cells, these effects in cancer are yet to be fully elucidated. In this study, we used a genetic approach with CRISPR-interference to knock down telomerase in TERT promoter-mutant glioblastoma cell lines. We show that this leads to a gradual and significant reduction in proliferation. This phenotype ultimately culminates in telomere crisis, with telomere shortening, activation of the DNA damage response pathway and formation of chromatin bridges. These data suggest that anti-telomerase therapy is a potential effective approach for glioblastoma tumors.
CBMT-26. SERIAL CHARACTERIZATION OF HYPERPOLARIZED [1-13C]PYRUVATE METABOLISM IN PATIENTS WITH GLIOMA AND THE INFLUENCE OF BEVACIZUMAB
Authors: Autry Adam , Gordon Jeremy , Chen Hsin-Yu , Lafontaine Marisa , Villanueva-Meyer Javier , Chang Susan , Xu Duan , Larson Peder , Vigneron Daniel , Li Yan
Published: November 2019

Treatment-related changes often mimic or mask tumor on standard anatomic imaging, making it difficult to monitor disease recurrence. Hyperpolarized (HP) carbon-13 MR imaging allows for real-time non-invasive measurement of metabolism, which may improve patient surveillance. Here, we focused on characterizing serial HP scans in patients undergoing treatment compared to healthy controls. Serial dynamic HP C-13 MRI scans were performed on 5 patients with recurrent glioma (22 total) and 3 healthy controls (4 total) using an echo-planar imaging sequence (2.88-8cm3 spatial resolution, 3s temporal resolution, 60s), following injection of 0.43mL/kg of 250mM HP [1-13C]pyruvate. Apparent rate constants were modeled for enzymatic conversion of pyruvate-to-lactate (kPL) via cytosolic lactate dehydrogenase and pyruvate-to-bicarbonate (kPB) via mitochondrial pyruvate dehydrogenase and carbonic anhydrase. Regions of interest included normal-appearing white matter (NAWM) and T2-hyperintense lesions (T2L), which were segmented from H-1 MR images and then aligned to the HP data. Carbon voxels containing >30% of NAWM or T2L were included in the analysis. Healthy controls demonstrated consistent kPL and kPB values over 4 scans in NAWM with SD/Mean of 5% and 12%, respectively. Compared to the median kPL-NAWM of 0.022s-1 in controls, the 5 patients had median serial kPL-NAWM values of 0.023, 0.023, 0.023, 0.029, and 0.015s-1, and mean serial ratios of kPL between T2L and NAWM (kPL-T2L/kPL-NAWM) of 1.22, 1.27, 1.05, 1.32, and 1.37s-1, indicating higher values in putative tumor. Median kPB-NAWM in controls was 0.004s-1 and ranged in patients 0.003-0.006s-1. Two patients with >4 serial scans, showed consistent kPL-NAWM over standard-of-care treatment and elevated kPL-T2L within new lesions, but up to 85% increase in kPL-NAWM with bevacizumab, which may be attributed to reduced BBB permeability. Stable patients generally demonstrated consistent kPL-T2L values that were lower compared to progressive patients. Future studies will include multi-parametric 1H imaging analysis in a larger patient population.
CBMT-39. TARGETING METABOLIC PATHWAYS IN HYPOXIA FOR GLIOBLASTOMA
Authors: Gruslova Aleksandra , Lodi Alessia , Li Mengxing , Zhou Mei , Garcia Michael , Tiziani Stefano , Brenner Andrew , Caflisch Laura
Published: November 2019

BACKGROUND

Metabolic adaptation to hypoxia is a crucial consideration in combating anti-angiogenic resistance. We previously explored the potential of targeting the peroxisomal fatty acid oxidation (FAO) pathway and observed higher potency to peroxisomal FAO inhibitor thioridazine in hypoxia in vitro. In this study we further examine the effects of peroxisomal FAO enzyme ACOX1, looking at differences in mitochondrial and peroxisomal FAO in hypoxia between subtypes, and explore additional metabolic pathways that can be potentially further studied.

METHODS

We utilized a CRISPR doxycycline-inducible U251 knockout cell line for the peroxisomal FAO gene ACOX1 and examined growth and viability in 2 weeks hypoxia (2% O2). We analyzed the gene expression of 13 peroxisomal and mitochondrial FAO enzymes in six different patient-derived cell lines. Finally, we characterized serum metabolites that are associated with tumor hypoxic volume, progression-free survival, and overall survival in patients undergoing clinical trial for TH302 and bevacizumab with bevacizumab refractory tumors.

RESULTS

We observed decreased cell growth and viability (p < .03) specifically in hypoxia but not normoxia with ACOX1 knock out. We saw some changes in gene expression (|ΔΔCt| >1) in hypoxia for all genes, which differed between cell lines. ACOX1 and CPT1A expression were strongly decreased (|ΔΔCt| >2) while ACADSB expression was strongly increased for the proneural cell line. ACOX1 expression was strongly decreased in our most thioridazine-sensitive cell line. ACOX2, ACADVL, CPT1A, CPT1C, and DECR2 expression were strongly increased in one of the proneural cell lines. Twelve polar metabolites were positively or negatively correlated (|r| >.4) with both hypoxic volume and either overall survival or progression-free survival.

CONCLUSION

Peroxisomal FAO and other metabolic pathways may be essential to target in order combat metabolic resistance during anti-angiogenic therapy. Better understanding differences in metabolism in different tumor environments will help determine which targets will be most therapeutically useful.
CSIG-05. TRPM7 INDUCES MECHANISTIC TARGET OF Rap1b THROUGH DOWNREGULATION OF miR-28-5p IN GLIOMA PROLIFERATION AND INVASION
Authors: Wan Jingwei , Guo Alyssa , Liu Mingli
Published: November 2019

Our previous findings demonstrate that TRPM7 is critical in regulating human glioma tumorigenesis. miRNA participate in complex regulatory networks that may affect almost every cellular and molecular processes in glioma formation and progression, because a specific miRNA may simultaneously regulate many targets; While, a single protein target can be regulated by different miRNAs. Here, we explored the role of miRNAs in the progression of human gliomas by comparing miRNA expression profiles due to differentially expressed TRPM7. We determined 1) miRNA targets of TRPM7 by miroRNA microarray analysis upon TRPM7 silencing in glioma cell lines. 2) whether TRPM7 regulates glioma cell proliferation (MTT) and migration/invasion (transwell invasion assay) through different functional domains by transfecting wild-type human TRPM7 (wtTRPM7) or constructs with the α-kinase domain deleted (Δkinase) or with a point mutation within the ATP binding site of the α-kinase domain (K1648R-KR) into glioma cells. 3) the roles of miR-28-5p in glioma tumorigenesis by over- or under-expressing miR-28-5p in vitro. 4) whether Rap1b is a target of miR28-5p and the role of Rap1b in glioma tumorigenesis. 5) whether Rap1b can counteract the miR28-5p function on glioma tumorigenesis. We found 1) a list of 16 downregulated and 10 upregulated miRNAs that are statistically significant with fold changes greater than 2 by TRPM7 knock-down by miRNA microarray, and miR-28-5p as a promising candidate for functional analyses. 2) cell invasion was significantly reduced in Δkinase or K1648R transfectants, indicating that TRPM7 kinase activity is required for glioma cell migration/invasion. 3) overexpression of miR-28-5p caused a significant decrease in cell proliferation and migration by targeting Rap1b. 4) Co-transfection with siRap1b with miR28-5p inhibitor reduced the glioma cell proliferation and invasion caused by the latter. In summary, TRPM7 induces mechanistic target of Rap1b through downregulation of miR-28-5p in glioma proliferation and invasion.
CSIG-11. CENTRAL NERVOUS SYSTEM TUMOR PATIENTS HAVE ELEVATED LEVELS OF CIRCULATING EXTRACELLULAR VESICLES
Authors: Ricklefs Franz , Maire Cecile , Kolbe Katharina , Holz Mareike , Reimer Rudolph , Glatzel Markus , Chiocca Ennio , Westphal Manfred , Lamszus Katrin
Published: November 2019

BACKGROUND

We previously demonstrated that extracellular vesicles (EV) from CNS tumors reflect the molecular subtype of the original tumor and mediate an exchange of pro-oncogenic signals. EVs are commonly characterized by nanoparticle analysis (NTA), electron microscopy and tetraspanin markers, including CD9, CD81 and CD63. It is unclear, however, to what extent circulating tumor EVs are utilizable for diagnostic purposes and how their marker profile overlaps with EVs derived from other cell types. Aiming to define markers that allow distinction and enrichment of glioma EVs from patient blood, we utilized Imaging Flow Cytometry (IFC) to discriminate single EVs via multiple surface markers.

METHODS

EVs were isolated from blood of patients suffering from glioblastoma (n=24), anaplastic astrocytoma (n=8), brain metastasis (n=7), meningioma (n=12), pituitary gland tumor (n=11), epilepsy (n=11) and from healthy controls (n=18) and were analyzed by IFC, immunoblotting, electron microscopy and NTA. In addition, circulating EVs from PALM-GFP-GL261 and PALM-GFP-CT2A tumor-bearing mice (n=5) as well as from glioblastoma stem-like (GSC) cultures (n=4), neural stem cells (NSC), cerebral endothelial cells (cEC) and T-cells (n=4) were characterized.

RESULTS

CNS tumor patients have significantly elevated levels of circulating EVs (P < 0.001), as measured by NTA and IFC. In particular, the proportion of double positive CD9+/CD81+, CD9+/CD63+and CD63+/CD81+EVs is increased in glioblastoma patients (p=0.018) compared with healthy controls[L1]. In accordance, cultured GSCs secrete increased levels of CD9+/CD81+EVs in vitro. In the two syngeneic murine PALM-GFP glioma models, only 0.1-0.01% of circulating plasma EVs were found to be derived from intracranial tumors, underlining the need to identify markers that can enrich tumor-specific EVs for molecular profiling.

CONCLUSION

Glioma patients display increased levels of circulating plasma EVs that can be profiled by IFC, which is a unique and novel technique that facilitates discrimination of different EV subpopulations.
CSIG-16. RECONCILING TUMOR HETEROGENEITY IN GLIOBLASTOMA USING A PATHWAY-BASED APPROACH
Authors: Alvarado Alvaro , Kawaguchi Riki , Coppola Giovanni , Goldman Steven , Kornblum Harley
Published: November 2019

Despite efforts to gain a deeper understanding of its molecular architecture, glioblastoma (GBM) remains uniformly fatal. While genome-based molecular subtyping has revealed that GBMs may be parsed into several distinct molecular categories, this insight has yielded little progress towards extending patient survival. In particular, the great phenotypic heterogeneity of GBM – both inter and intratumorally – has hindered therapeutic efforts. To this end, we interrogated tumor samples using a pathway-based approach to resolve tumoral heterogeneity. Gene set enrichment analysis (GSEA) was applied to gene expression data and used to provide an overview of each sample that was then compared to others, generating sample clusters based on overall patterns of enrichment. The Cancer Genome Atlas (TCGA) samples were clustered using canonical and oncogenic signatures and in both cases the clustering was distinct from the molecular subtypes previously reported. Using principal component analysis (PCA) and other bioinformatics tools, we extracted gene sets to further characterize the pathways contributing to each of these clusters. We generated gene lists of the top common elements and Ingenuity pathway analysis exposed molecular targets that control critical pathways of each identified cluster. Similar analyses were completed in a gene expression database of patient-derived gliomasphere lines and molecular targets were also obtained. We found E2F1 to be a strong target based on gene lists from both databases. A cluster of gliomasphere lines have high enrichment scores for the gene list predicted to depend on E2F1. In vitro genetic perturbation showed decrease stem cell frequency and lower expression of cell cycle progression genes in cell lines from this cluster exclusively. Other cluster-specific targets are being validated and in vivo studies will follow momentarily. Our studies relate intertumoral heterogeneity to critical cellular pathways dysregulated in GBM, with the ultimate goal of establishing a pipeline for patient- and tumor-specific precision medicine.
CSIG-28. ROLE OF ALTERNATIVE SPLICING IN CONFERRING SPATIAL HETEROGENEITY SIGNATURES IN GBM
Authors: Ghosh Sadashib , Pavlyukov Marat S , Bastola Soniya , Li Chaoxi , Yamaguchi Shinobu , Komarova Svetlana , Yamashita Daisuke , Nakano Ichiro
Published: November 2019

Therapeutic interventions induce cell stress to trigger apoptosis in tumor cells. Specific cellular stressors, including those initiated by radio-chemotherapy, activate distinct pro-death proteins through a multitude of mechanisms. Apoptosis consists of highly regulated pathways involving post-translational modifications and cleavage of proteins leading to sequential inactivation of the main cellular processes e.g. cell cycle progression. Recently, we demonstrated that apoptotic bodies/ApoEVs in GBM transfer spliceosomal machinery components to neighboring cells, which are subsequently internalized and confer survival advantage through changes in mRNA splicing. Following the validation of the role of RBM11, a spliceosomal component in the said intercellular communication, we extended our findings in the characterization of spatially distinct clonally derived sphere lines from tumor edge and core-located tissues from GBM patients. We analyzed the expression of spliceosomal genes in edge and core-derived clones and found spatially distinct splicing capabilities and that the genes that were affected by alternative splicing events in edge and core cells have different splicing of genes that are involved in ubiquitination and regulate cell cycle progression. Downstream analyses revealed that the most promising target is MDM2. Importantly, this gene regulates cell cycle via ubiquitination. Further, western blot revealed differential expression of both RBM11 and MDM2 in egde and core-derived clones.Collectively, the data so far provides motivation for the possibility of finding cellular vulnerabilities in the splicing machinery and thus actionable targets for intervention that accounts for the bearings of spatial heterogeneity.
CMET-08. CEREBROSPINAL FLUID CARCINOEMBRYONIC ANTIGEN PREDICT PROGNOSIS IN LEPTOMENINGEAL METASTASIS FROM NON-SMALL CELL LUNG CANCER
Authors: Zhen Junjie , Li Shaoqun , Wen Lei , Lai Mingyao , Cai Linbo
Published: November 2019

BACKGROUND

Leptomeningeal metastasis (LM) is a detrimental complication of patients with non-small cell lung cancer (NSCLC) and its incidence has increased due to recent improvements in survival. The aim of this study was to identify the clinicopathological features and prognostic factors related to overall survival in NSCLC patients with LM.

METHODS

Seventy-four consecutive patients diagnosed with LM from NSCLC between 2009 and 2018 in Guangdong Sanjiu Brain Hospital were retrospectively reviewed.

RESULTS

Median KPS at diagnosis of LM were 60 (range, 20–90). Forty-seven (63.5%) patients harboring epidermal growth factor receptor (EGFR) or anaplasticlymphoma kinase (ALK) mutation while other twenty-seven patients (36.5%) were wild type or unknown status. Local treatment for LM consisted of whole-brain radiotherapy (WBRT) (52.7%), ventriculoperitoneal (VP) shunt (6.8%) and external drainage (6.8%). Systematic therapy for LM included EGFR or ALK tyrosine kinase inhibitors (TKI) (59.5%), chemotherapy (40.5%) and bevacizumab (8.1%). The median overall survival from diagnosis of LM to death was 8.1 months (95% confidence interval: 5.2 to 11.0). Patients with high Cerebrospinal Fluid (CSF) carcinoembryonic antigen (CEA) level (＞50ng/ml) had worse prognosis compared with those low CSF CEA level (≤50ng/ml) ones (p=0.02). However, there was no significant difference in survival between patients with high serum CEA and those with low serum CEA (p=0.645). EGFR/ALK mutation and EGFR/ALK TKI after LM were also identified as variables that had prognostic influence on survival, while KPS, concurrent brain metastasis, WBRT and chemotherapy had no prognostic value for survival.

CONCLUSION

Median overall survival was higher than historical experience in this retrospective analysis. It is CSF CEA level, but not serum CEA level that correlated with prognosis for LM from NSCLC.
CMET-09. A UNIQUE CASE OF PRIMARY GLIOSARCOMA WITH METASTASIS TO SACRUM ON BEVACIZUMAB
Authors: Hrachova Maya , Xiao-Tang Kong , Perez Rosenthal Mari
Published: November 2019

INTRODUCTION

Gliosarcoma is a rare variant of glioblastoma that accounts for approximately 0.48% of all adult brain tumors. Although, metastatic potential of gliosarcoma via hematogenous route has been proposed in the past, we report the first case of metastasis to the sacrum while undergoing treatment on bevacizumab. CASE REPORT: A 40-year-old woman presented with acute onset severe headache with pertinent examination findings of left upper extremity pronator drift. Imaging revealed right frontal lobe enhancing mass measuring 4.5 x 3.7 cm associated with edema and 10 mm leftward midline shift. A right frontal craniotomy for tumor debulking showed gliosarcoma (IDH wild-type, WHO grade 4). She was initiated on radiotherapy with concomitant and adjuvant temozolomide via Stupp’s protocol after second debulking surgery. Chemotherapy regimen was changed to bevacizumab when tumor progression was identified. Within six months of initiation of bevacizumab, she developed left leg shooting pain. Imaging revealed heterogeneously enhancing mass in the left hemisacral region measuring 6.2 cm concerning for metastatic process. Sacral bone biopsy showed malignant cells which were negative for an extensive immunohistochemical panel (including GFAP and Olig2), suggesting metastasis of the sarcomatous element of gliosarcoma and arguing against a second malignancy. Next generation sequencing performed on both the intracranial and sacral tumor showed an identical molecular prolife (including PTEN, NF1, TERT and TP53 genomic alterations), confirming common origin. After completion of radiation therapy to sacral region, chemotherapy regimen included lomustine followed by pembrolizumab. The patient died at 14 months after initial presentation due to disease progression.

DISCUSSION

To the best of our knowledge, this is the first case primary of gliosarcoma with metastases to the sacrum while evolved on chemotherapy with bevacizumab. The aim of this report is to bring awareness to medical community in order to expedite the diagnosis and management.
CMET-14. BRAIN METASTASES: A NEW PATHOPHYSIOLOGY, A NEW TREATMENT PARADIGM, AND, PERHAPS, A NEW PROGNOSIS
Authors: Dowd Richard , Ouyang Tao , Thamburaj Krishnamoorthy , Aregawi Dawit , Safran Howard , Zacharia Brad , Glantz Michael
Published: November 2019

INTRODUCTION

Brain metastases are widely held to reach the CNS through the blood stream. We provide evidence that the initial site of most CNS metastases is the CSF, with subsequent invasion of brain parenchyma. We also model the therapeutic implications of this novel hypothesis.

METHODS

Two neuro-radiologists independently assessed whether brain metastases were contiguous with CSF spaces in 200 consecutive patients using pre-treatment MRI. CSF was examined for malignant cells in 66 newly diagnosed, previously untreated patients. We contoured normal brain MRIs of 3 patients to calculate the percentage of brain within 5 mm of a CSF space. We queried an international neoplastic meningitis database to document response of brain metastases to intra-CSF chemotherapy.

RESULTS

Mean age was 64.2. One hundred patients were male; 143 had lung cancer, 15 melanoma, 12 gastrointestinal, 11 breast, 9 renal, 7 bladder. Mean number of metastases was 4.63. Eighty-five percent of metastases touched a CSF space. In 67% of patients, all metastases touched a CSF space. Neither histology, number or size of metastases, nor patient age predicted contiguity with CSF spaces. In our consecutive subset of patients, 44% (10/23) with one, 46% (5/11) with two, 63% (5/8) with three, and 71% (17/24) with >3 metastases had malignant cells in the CSF (R2=0.93, p=0.037). Five of 7 patients with both brain and CSF metastases receiving only IT chemotherapy experienced a substantial reduction in the size of at least some metastases. Up to 75% of the brain parenchyma lies within 5 mm of CSF spaces.

CONCLUSIONS

Our data suggest that brain metastases may access the CNS through the CSF rather than the bloodstream. IT chemotherapy may treat brain metastases. We suggest that the CSF should be monitored in all patients with, or at risk for, brain metastases. True cures may require treatment of the CSF space.
CMET-18. IMPACT OF KRAS MUTATION STATUS ON THE EFFICACY OF IMMUNOTHERAPY IN LUNG CANCER BRAIN METASTASES
Authors: Lauko Adam , Ali Assad , Sagar Soumya , Barnett Addison , Li Hong , Chao Samuel , Stevens Glen , Pennell Nathan , Peereboom David , Yu Jennifer , Murphy Erin , Angelov Lilyana , Funchain Pauline , Mohammadi Alireza , Suh John , Barnett Gene , Ahluwalia Manmeet
Published: November 2019

BACKGROUND

Immunotherapy is increasingly used in patients with non-small cell lung cancer brain metastases (NSCLCBM). KRAS mutations are associated with worse prognosis and there is no FDA approved targeted therapy. KRAS mutations are associated with increased expression of PD-L1. We evaluated the outcomes of NSCLCBM with KRAS mutations treated with immune checkpoint inhibitors (ICI).

METHODS

We reviewed 800 patients with NSCLCBM treated at our tertiary care center. 226 had known KRAS mutational status, 121 of which received immunotherapy. Overall survival (OS) was calculated from either the start of immunotherapy (when both groups received immunotherapy) or from the date of diagnosis of brain metastasis. Kaplan-Meier method and Cox Proportional hazard model were utilized to determine differences in OS and the Chi-square test was utilized to determine differences in PD-L1 expression.

RESULTS

In 109 patients where both KRAS and PD-L1 status were known, KRAS mutations had greater PD-L1 expression (80.1% vs 61.9% positive, p=0.04). There was no difference in OS between KRAS mutant vs KRAS wild-type patients treated with immunotherapy. Median survival from the start of immunotherapy was 15.6 vs 15.5 months respectively (p=0.7), after adjusting for age, KPS, lesion number and extra-cranial metastasis (HR = .91, p=.7). Patients with KRAS mutations treated with immunotherapy versus those who received chemotherapy had a 1-year OS from the diagnosis of brain metastasis of 60.9% vs 38.7% respectively (trending towards significance, p=0.05). KRAS wild-type patients treated with immunotherapy versus those who did not receive immunotherapy had a 1-year OS from the diagnosis of brain metastasis of 61.9% vs 62.5% (p=0.85), respectively.

DISCUSSION

KRAS mutations are associated with increased PD-L1 expression. Use of immunotherapy negates the poor outcomes seen traditionally in patients with NSCLCBM and KRAS mutations and it improves survival compared to use of chemotherapy. Our experience supports the use of immunotherapy in these patients.
CMET-30. COMPREHENSIVE METHYLOME ANALYSIS OF EGFR-MUTANT PRIMARY LUNG ADENOCARCINOMA AND MATCHED BRAIN METASTASIS
Authors: Mamatjan Yasin , Cabanero Michael , Zuccato Jeffrey , Weiss Jessica , Karimi Shirin , Sorotsky Hadas , Tsao Ming , Aldape Kenneth , Shepherd Frances , Zadeh Gelareh
Published: November 2019

Brain metastasis (BM) in patients with EGFR-mutant lung adenocarcinoma is a major determinant of overall survival. Novel insight into the genetic and epigenetic underpinnings of BM development is lacking. The aim of this study is to compare the methylome of EGFR-mutant primary lung adenocarcinoma (EGFRM-PLA) and matched BM to identify important alterations for the mechanisms of BM. Matched EGFRM-PLA and BM tumors from seven patients were profiled using the Illumina Infinium MethylationEPIC BeadChip array. Unsupervised clustering analyses of the 14 samples showed a similar whole DNA methylation signatures between EGFRM-PLA and BM tumors. Furthermore, PCA plot highlighted that seven matched BM and lung tumor samples were clustered together closely based on matching pairs for the most variable probes (2.5K to 10K). These observations indicate high level of concordance and the same cell of origin. However, these fourteen samples clustered into two groups based on tumor site being lung or brain based on 83K differentially methylated CpG sites. Of the 83K probes, 2.4K were either hypermethylated or hypomethylated in all lung samples. A quarter of these 2.4K probes were located in promoter regions. Specifically, we identified differences in methylation status of EGFR/ALK promoter regions in lung tumors versus BM. CNV analyses showed higher deep deletions of chromosomes and genes in BM compared to EGFRM-PLA. Leukocytes unmethylation for purity (LUMP) scores which indicate immune cell infiltration were similar between lung and BM pairs (Mean LUMP_score=0.64) consistent with high immune cell infiltration. Our results indicated a similar whole DNA methylation signature of EGFRM-PLA and matched BM, while comprehensive analysis identified important differentially methylated probes. Distinct differences in CNV alterations were observed in lung versus brain samples. The BM and EGFRM-PLA showed similar tumor purity and immune cell components. Overall, tumor methylation profiling provides clinically important information regarding biology of BM in EGFRM-PLA.
CMET-31. WHOLE BRAIN RADIOTHERAPY VERSUS STEREOTACTIC RADIOSURGERY IN POOR-PROGNOSIS PATIENTS WITH 1 – 10 BRAIN METASTASES: A RANDOMIZED FEASIBILITY STUDY
Authors: Nichol Alan , Raman Srinivas , Mou Benjamin , Hsu Fred , Valev Boris , Cheung Arthur , Vallières Isabelle , Beaton Laura , Rackley Thomas , Gondara Lovedeep
Published: November 2019

BACKGROUND

The clinical advantage of stereotactic radiosurgery (SRS) over whole brain radiotherapy (WBRT) in patients with brain metastases and poor prognosis is controversial. To investigate the feasibility of a phase III clinical trial in a population of patients with poor prognosis, we conducted a randomized feasibility study of WBRT versus SRS.

METHODS

Patients with Karnofsky performance status (KPS) ≥ 70, life expectancy of 3–6 months, based on both Diagnosis-Specific Graded Prognostic Assessments and attending oncologist opinion, and 1– 10 brain metastases with a diameter ≤ 4 cm were enrolled at six Canadian cancer centers. Patients were randomly assigned to WBRT (20 Gy in 5 fractions) or SRS (15 Gy in 1 fraction). The primary endpoint was the rate of accrual. A secondary endpoint was the ratio of screened subjects to accrued subjects. This trial is registered with ClinicalTrials.gov (NCT02220491).

RESULTS

Between January 2015 and November 2017, 210 were screened to enroll 22 patients (9.5 screened/participant) and 20 patients were randomized. The accrual rate was 0.63 patients / month. The most common reasons for exclusion were: estimated median survival outside 3–6 months (n = 40), baseline KPS below 70 (n = 28), and > 10 brain metastases (n = 28). The median survival was 7.0 months. The overall survival was 9.5 months (n = 11) for patients who had subsequent systemic therapy, compared to 3.7 months (n = 9) in patients who had none. In both arms, the cumulative incidence of retreatment with brain radiotherapy was 40%.

CONCLUSIONS

Accrual was slow and the median survival was longer than expected, but a randomized trial evaluating WBRT vs SRS in patients with poor prognosis would likely be feasible by enrolling only patients with no remaining systemic therapy options.
COMP-16. COMPREHENSIVE TRANSCRIPTOMIC ANALYSIS OF SINGLE CELLS FROM RECURRENT AND PRIMARY GLIOBLASTOMA TO PREDICT CELL-TYPE SPECIFIC THERAPEUTICS
Authors: Suter Robert , Stathias Vasileios , Jermakowicz Anna , Semonche Alexa , Ivan Michael , Komotar Ricardo , Schürer Stephan , Ayad Nagi
Published: November 2019

Glioblastoma (GBM) remains the most common adult brain tumor, with poor survival expectations, and no new therapeutic modalities approved in the last decade. Our laboratories have recently demonstrated that the integration of a transcriptional disease signature obtained from The Cancer Genome Atlas’ GBM dataset with transcriptional cell drug-response signatures in the LINCS L1000 dataset yields possible combinatorial therapeutics. Considering the extreme intra-tumor heterogeneity associated with the disease, we hypothesize that the utilization of single-cell RNA-sequencing (scRNA-seq) of patient tumors will further strengthen our predictive model by providing insight on the unique transcriptomes of the cellular niches present within these tumors, and into the transcriptional dynamics of these same cellular niches. By sequencing single-cell transcriptomes from recurrent GBM tumors resected from patients at the University of Miami, and integrating our datasets with previously published scRNA-seq data from primary GBM tumors, we are able to gain additional insight into the differences between these clinical distinctions. We have analyzed the differential expression of kinases both across and within distinct cell populations of primary and recurrent GBM tumors. This transcriptional map of kinase expression represents the heterogeneity of potential targets within individual tumors and between recurrent and primary GBM. Additionally, by generating disease signatures unique to each cellular population, and integrating these with transcriptional drug-response signatures from LINCS, we are able to predict compounds to target specific cell populations within GMB tumors. Additional computational techniques such as RNA velocity analysis and cell cycle scoring elucidate temporal insights to further prioritize these cell-type specific therapeutics, and reveal the intra-cellular dynamics present within these tumors. Collectively, our studies suggest that we have developed a novel omics pipeline based on the single cell RNA-sequencing of individual GBM cells that addresses intra-tumor heterogeneity, and may lead to novel therapeutic combinations for the treatment of this incurable disease.
DRES-01. EFFICACY OF EGFR PLUS TNF INHIBITION IN A PRECLINICAL MODEL OF GLIOBLASTOMA
Authors: Guo Gao , Gong Ke , Sarkaria Jann , Habib Amyn
Published: November 2019

EGFR gene amplification and mutation are common in glioblastoma (GBM), but EGFR inhibition is not effective in treating this tumor. EGFR inhibition may fail because EGFR is not a driver of the malignant phenotype in GBM, or because adaptive compensatory mechanisms are triggered by EGFR inhibition that prevent cell death from a loss of EGFR signaling. We have recently identified a TNFα-JNK-Axl-ERK signaling axis that mediates primary resistance to EGFR inhibition in GBM. Temozolomide (TMZ) is the most effective chemotherapy in GBM, although it has only a modest effect on overall survival. The efficacy of TMZ depends on the absence of the DNA repair protein O6-alkylguanine DNA alkyltransferase (MGMT) which reverses the DNA damage induced by TMZ. The MGMT promoter is hypermethylated in about 45% of GBMs, resulting in lack of MGMT expression. TMZ is less effective in MGMT unmethylated GBMs. Moreover, even initially responsive tumors develop a secondary resistance to TMZ. No treatment is effective in recurrent TMZ-resistant GBM. In this study, we compare the efficacy of temozolomide versus EGFR plus TNF inhibition in an orthotopic model of GBM. We find that efficacy of the two treatments is similar in MGMT-methylated GBMs. However, in MGMT-unmethylated GBMs, a combination of EGFR plus TNF inhibition is more effective. We demonstrate that the two treatment approaches target distinct and non-overlapping pathways. Furthermore, and importantly, EGFR plus TNF inhibition remains effective in TMZ-resistant recurrent GBMs and in GBMs rendered experimentally resistant to TMZ. Since the EGFR is expressed in the majority of GBMs, EGFR inhibition combined with a blunting of the accompanying TNF-driven adaptive response could be a broadly applicable and viable therapeutic approach in primary GBMs with MGMT unmethylation and in recurrent GBMs.
DRES-05. PREDICTORS OF SENSITIVITY TO COMBINED TEMOZOLOMIDE AND PARP INHIBITOR IN GLIOMA
Authors: Nagashima Hiroaki , Higuchi Fumi , Lee Christine , Rafferty Seamus , Miller Julie , Wakimoto Hiroaki , Cahill Daniel
Published: November 2019

Agents targeting the PARP enzyme family are under active development for the treatment of gliomas. PARP inhibitors (PARPi) can enhance the effect of temozolomide (TMZ) in IDH wild-type glioblastomas, and in addition recent studies have shown that PARP inhibitors can be selectively lethal in IDH1 mutant cancers. Here, we sought to identify predictors of sensitivity and resistance to PARP inhibition in gliomas. We treated 4 IDH1 mutant and 8 IDH wild-type glioma lines, as well as IDH1 mutant fibrosarcoma line HT1080, with TMZ, the PARPi olaparib, or the combination, and assessed cellular growth and survival. In dose response assessments, 7 out of 13 lines were sensitive to olaparib monotherapy (3 IDH1 mutant and 4 IDH wild-type). Combination with TMZ resulted in 6 of 13 lines responding to dual therapy, with an additive effect seen in 5 PARPi monotherapy sensitive gliomas. Notably, 5 of the 6 lines responsive to the combination harbored CDKN2A deletion, compared to none of the non-responsive lines (p=.0021). Treatment with CDK inhibitor palbociclib partially reversed sensitivity to TMZ+PARPi in HT1080, supporting a mechanistic basis for this association. PARPi sensitivity in glioma lines can be augmented by the addition of TMZ. CDKN2A deletion may serve as a potential biomarker identifying tumors sensitive to this combination therapy.