Primary Malignant Brain Research Articles

Glioblastoma in the Cerebellopontine Angle in a Patient with Neurofibromatosis Type I: A Case Report and Review of the Literature

Abstract Introduction Glioblastoma multiforme (GBM) is the most common primary brain malignancy in adults and is typically in the supratentorial cerebral hemispheres. It has been reported to occur in the posterior fossa at the cerebellopontine angle (CPA), but the incidence is extremely rare. Case Report We report a case of a patient with a history of neurofibromatosis type I (NFI) diagnosed with a GBM arising in the CPA after presenting with facial numbness and pain. Patients with NFI are known to have an increased risk of developing both benign and malignant tumors, including a propensity for brainstem gliomas. However, there is no known association between NFI and tumors of the CPA. We believe this is the first reported case of a GBM of the CPA in a patient with NFI. Conclusion Although rare, GBM should be included in the differential diagnosis of a patient with a CPA tumor, especially in patients with increased risk of malignant pathology.

Brain Tumor Segmentation and Survival Prediction Using Multimodal MRI Scans With Deep Learning.

Gliomas are the most common primary brain malignancies. Accurate and robust tumor segmentation and prediction of patients' overall survival are important for diagnosis, treatment planning and risk factor identification. Here we present a deep learning-based framework for brain tumor segmentation and survival prediction in glioma, using multimodal MRI scans. For tumor segmentation, we use ensembles of three different 3D CNN architectures for robust performance through a majority rule. This approach can effectively reduce model bias and boost performance. For survival prediction, we extract 4,524 radiomic features from segmented tumor regions, then, a decision tree and cross validation are used to select potent features. Finally, a random forest model is trained to predict the overall survival of patients. The 2018 MICCAI Multimodal Brain Tumor Segmentation Challenge (BraTS), ranks our method at 2nd and 5th place out of 60+ participating teams for survival prediction tasks and segmentation tasks respectively, achieving a promising 61.0% accuracy on the classification of short-survivors, mid-survivors and long-survivors.

Abstract 570: A glioblastoma translational pipeline: discovery of novel tumor antigens that drive GBM recurrence

Abstract Background: Glioblastoma (GBM) is the most common malignant primary adult brain tumor, characterized by extensive cellular and genetic heterogeneity. Even with surgery, temozolomide chemotherapy and radiation, tumor re-growth and patient relapse are inevitable, with a median survivorship of just 15 months. Genomic profiling studies have shown that clonal evolution within GBM may be driven by cancer treatment, such that the recurrence may no longer resemble the genetic landscape of the original primary tumor. Furthermore, intratumoral heterogeneity associated with clonal evolution complicates biomarker discovery and treatment personalization and underlies treatment failure. Thus, modeling clonal heterogeneity and evolution to understand cancer progression is critical for the development of effective therapeutic approaches. We aim to identify new therapeutic targets that drive clonal evolution in treatment-refractory GBM and develop novel and empirical therapeutic paradigms targeting recurrent GBM. Experimental Procedure: We employed a transcriptomic, proteomic and functional genomics approach to discover and validate genes that drive GBM recurrence. Using a therapy-adapted patient-derived xenograft (PDX) model of treatment-refractory GBM, we profiled the transcriptomic and proteomic landscape of treatment-naïve primary GBM through conventional chemotherapy and radiation therapy, and into recurrence. To complement the transcriptomic data, we used an unbiased genome-wide CRISPR-Cas9 screening platform to identify genes essential for self-renewal in recurrent GBM, as well as to identify novel sensitizers and suppressors of conventional therapy. Furthermore, we coupled cellular DNA barcoding technology with our PDX model to profile the clonal evolution of tumor cells through therapy. Results: Integrative analysis of deep sequencing and surface proteomics of tumor cells harvested at tumor formation, minimal residual disease after chemoradiotherapy, and tumor recurrence from the PDX model resulted in the identification of novel therapeutic targets in treatment-refractory GBM. Using CRISPR, potential targets were knocked out in patient-derived GBMs in order to characterize the effect on self-renewal and tumor formation. We report the successful barcoding of patient-derived primary, treatment-naïve GSCs at a single cell resolution that were expanded into clonal populations, intracranially engrafted in immunodeficient mice and treated with SoC therapy. Conclusion: We have generated a translational pipeline from initial target discovery, through target validation, to building new biotherapeutics against novel targets, and preclinical testing in our PDX model of treatment-resistant GBM. A promising lead panel of biotherapeutic modalities is being translated into early clinical development, generating targeted therapies and hope for future GBM patients. Note: This abstract was not presented at the meeting. Citation Format: Parvez Vora, Chitra Venugopal, Chirayu Chokshi, Maleeha Qazi, Nazanin Tatari, Kevin Brown, Nicholas Yelle, Jarrett Adams, David Tieu, Mathieu Seyfrid, Mohini Singh, Neil Savage, Minomi Subapanditha, David Bakhshinyan, Laura Kuhlmann, Thomas Kislinger, Sachdev Sidhu, Jason Moffat, Sheila Kumari Singh. A glioblastoma translational pipeline: discovery of novel tumor antigens that drive GBM recurrence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 570.

Abstract 3575: Dysregulated expression of lncRNAs in glioblastoma multiforme and their association with overall survival

Abstract Introduction: Glioblastoma multiforme (GBM) is the most frequent primary brain malignancy of astrocytic origin. The prognosis remains very poor with the median overall survival (OS) being between 12 and 16 months from diagnosis despite early use of conventional medical therapy. Identifying new therapeutic targets, as well as prognostic and predictive biomarkers for accurate stratification of patients is therefore of utmost importance. Long non-coding RNAs (lncRNAs) are regulators of gene expression having critical impact on both physiological processes and the molecular pathology of GBM, indicating their potential as biomarkers and therapeutic targets. Material and Methods: Our study included 219 GBM patients and 29 patients with non-dominant anterior temporal cortexes resected during surgery for intractable epilepsy. Informed consent approved by the local Ethical Commission was obtained from each patient. RNA (RIN > 8) from 77 specimens was used for next-generation RNA sequencing (RNAseq). rRNA depletion and cDNA library preparation were done with RiboCop rRNA Depletion Kit V1.2 (Lexogen) and NEBNext Ultra II Directional RNA Library Prep Kit for Illumina (NEB), respectively. RNAseq was performed using NextSeq 500 High Output Kit and NextSeq 500 instrument (both Illumina). 8,414 lncRNAs and their sequential variants with non-zero RPKM at least in one sample were statistically evaluated. The alignment and target counts were performed with CLC genomic workbench. Selected significantly dysregulated lncRNAs between GBM and non-tumor controls were analyzed in a larger cohort of 188 specimens by qRT-PCR and the expression data normalized to PPIA was then evaluated by Mann-Whitney U test. Results: Statistical analysis revealed 538 (P < 0.001) dysregulated lncRNAs in GBMs compared to non-tumor brain tissue samples. The expression of top 10 downregulated lncRNAs (SNAI3-AS1, LINC00882, RFPL1S, MIR137HG, TTLL7-IT1, PWAR6, LINC00634, LINC00632, DGCR5, LINC00982; logFC ≤ -2; P < 0.001) and 1 upregulated lncRNA (BTN2A3P; logFC ≥ 2; P < 0.001) in GBM and non-tumor controls was successfully validated by qRT-PCR (P < 0.0001). Moreover, the statistical analysis revealed 22 lncRNAs significantly dysregulated between patients with OS less than 12 months and those with OS equal or more than 12 months (P < 0.01). Conclusion: We observed significant dysregulation of lncRNAs in GBM tissues compared to non-tumor controls based on the results of both RNASeq and qRT-PCR. We also found 22 lncRNAs to be dysregulated in relation to overall survival. Our study indicates that lncRNAs could serve as promising diagnostic and prognostic biomarkers in GBM. This work was supported by Ministry of Health of the Czech Republic grant nr. NV18-03-00398, grant of Czech Grant Agency nr. 17-17636S, and by the Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (LQ1601). Citation Format: Marek Vecera, Jan Oppelt, Lenka Radova, Radim Lipina, Stefan Reguli, Martin Smrcka, Radim Jancalek, Michal Filip, Marketa Hermanova, Leos Kren, Jiri Sana, Alena Kopkova, Julia Kovacova, Ondrej Slaby. Dysregulated expression of lncRNAs in glioblastoma multiforme and their association with overall survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3575.

Upregulated necroptosis-pathway-associated genes are unfavorable prognostic markers in low-grade glioma and glioblastoma multiforme.

BackgroundGlioma accounts for 70% of primary brain malignancies in adults with unfavorable prognoses. In the past decades, much efforts have been invested to identify better biomarkers for predicting prognoses. Recently, necroptosis has been reported as a specialized pathway of programmed necrosis. Moreover, regulators of necroptosis-pathway-associated genes (RIPK1, RIPK3 and MLKL) were reported to be related to prognoses of many types of tumors. However, the prognostic value of these genes in diffuse glioma including low-grade glioma (LGG) and glioblastoma multiforme (GBM) remains unknown.MethodsAn online tool-Gene Expression Profiling Interactive Analysis (GEPIA) (http://gepia.cancer-pku.cn/) was used to analyze different expression of necroptosis-pathway-associated genes between tumor and normal tissue, correlation between RIPK1, RIPK3 and MLKL, the relationship between necroptosis-pathway-associated genes and prognosis [overall survival (OS) and disease-free survival (DFS)] in LGG and GBM. The median expression of RIPK1, RIPK3 and MLKL was used to divide patients into high- versus low-expression group. All graphic presentations were drawn by Gepia database.ResultsExpression of RIPK1 and RIPK3 were significantly higher in tumor tissue of GBM as compared with normal tissue. A moderate correlation between MLKL and RIPK3 was demonstrated in both LGG (R =0.79) and GBM (R =0.79). In LGG, higher expression of RIPK1, RIPK3, and MLKL were associated with poor OS and DFS with HR values of 2.2, 2, 1.9 for OS and 1.7, 1.8, 1.6 for DFS, respectively. In GBM, only a higher expression of MLKL was associated with worse OS and DFS with HR values of 1.5 and 1.6, respectively.ConclusionsRegulators of necroptosis-pathway-associated genes appear to have a potential to serve as biomarkers of prognosis in both LGG and GBM.

Targeting the androgen receptor as a novel therapeutic strategy for high-grade gliomas by suppressing glioma cancer stem cells.

e13504 Background: Glioblastoma (GBM) is the most aggressive and most common type of primary brain malignancies with median overall survival being only 20.9 months. The incidence of GBM is 50% greater in men than in women, and GBM transplanted into animals grow at a slower rate in females compared with males. Gender difference in GBM indicates that sex hormones such as androgen receptor (AR) may be involved in the tumorigenesis of GBM. A newer generation of AR antagonist, Enzalutamide, is available for prostate cancer treatment in clinic and can pass the blood-brain barrier, thus a good candidate for GBM treatment. Methods: Cell proliferation assay, cell cycle analysis, and cell apoptosis assay were performed on different GBM cell lines after Enzalutamide treatment. After treating GBM cells with or without Enzalutamide in mono-layer cell culturing or tumor spheres, cancer stem cell sub-population (CD133+ cells) in different groups was compared using flow cytometry. After enriching GBM cancer stem cells by sorting CD133+ U87MG cells out, cell proliferation assay was performed on CD133+ U87MG cells. Western blotting was performed comparing marker gene expression levels including CD133 and c-Myc with total protein isolated from GBM cells treated with Enzalutamide at different time points. A syngeneic orthotopic GBM mouse model was used for in vivo study. The size of tumors in the brain was monitored weekly with and without Enzalutamide treatment by in vivo imaging system for the luciferase activities. Results: Enzalutamide inhibited the proliferation of GBM cells both in vitro and in vivo. Enzalutamide induced apoptosis of GBM cells as well as arrested the cell cycle at G2/M phase in a cell cycle that has a potential of radio-sensitizing effect. Enzalutamide decreased the cancer stem cells population both in cultured mono-layer cells and in tumor spheres. Enzalutamide inhibited the proliferation of CD133+ U87MG cells after four days’ treatment. c-Myc is a proto-oncogene and required for maintenance of GBM cancer stem cells. Both CD133 and c-Myc expression levels decreased in GBM cell lines after Enzalutamide treatment in a time-dependent manner. Conclusions: Enzalutamide targets cancer stem cells and inhibits the proliferation of GBM.

Role of Surface Chemistry in Mediating the Uptake of Ultrasmall Iron Oxide Nanoparticles by Cancer Cells.

Ultrasmall iron oxide nanoparticles (USIONPs) (<4 nm) have recently attracted significant attention because of their potential as positive T1 magnetic resonance imaging (MRI) contrast agent contrary to larger superparamagnetic iron oxide nanoparticles (>6 nm) which act as negative T2 MRI contrast agents. However, studies on the cellular uptake behavior of these nanoparticles are very limited compared to their counterpart, larger-sized superparamagnetic iron oxide nanoparticles. In particular, the effects of specific nanoparticle parameters on the cellular uptake behavior of USIONPs by various cancer cells are not available. Here, we specifically investigated the role of USIONPs' surface functionalities [tannic acid (TA) and quinic acid (QA)] in mediating cellular uptake behavior of cancer cells pertaining to primary (U87 cells) and metastatic (MDA-MB-231Br cells) brain malignancies. Here, we chose TA and QA as representative capping molecules, wherein TA coating provides a general negatively charged nontargeting surface while QA provides a tumor-targeting surface as QA and its derivatives are known to interact with selectin receptors expressed on tumor cells and tumor endothelium. We observed differential cellular uptake in the case of TA- and QA-coated USIONPs by cancer cells. Both the cell types showed significantly higher cellular uptake of QA-coated USIONPs compared to TA-coated USIONPs at 4, 24, and 72 h. Blocking studies indicated that P-selectin cell surface receptors, in part, mediated the cellular uptake of QA-coated USIONPs. Given that P-selectin is overexpressed in cancer cells, tumor microenvironment, and at the metastatic niche, QA-coated USIONPs hold potential to be utilized as a platform for tumor-targeted drug delivery and in imaging and detection of primary and metastatic tumors.

Combined treatment with 2'-hydroxycinnamaldehyde and temozolomide suppresses glioblastoma tumorspheres by decreasing stemness and invasiveness.

Glioblastoma (GBM) is the most common and aggressive human primary brain malignancy. The key properties of GBM, stemness and invasiveness, are known to be associated with a highly unfavorable prognosis. Notably, the process of epithelial-mesenchymal transition (EMT) is closely related to the progression of GBM. On the basis of reports that 2'-hydroxycinnamaldehyde (HCA) and its derivative, 2'-benzoyloxycinnamaldehyde (BCA), suppresses EMT in several human cancer cells, we sought to evaluate the therapeutic efficacy of HCA and BCA, alone and in combination with temozolomide (TMZ), on GBM tumorspheres (TSs). Two human GBM TSs were treated with HCA, BCA, or TMZ. Therapeutic effects were evaluated by measuring ATP levels, neurosphere formation, 3D-invasion in collagen matrix, and viability. Protein expression profiles after drug treatment were evaluated by western blotting. In vivo anticancer efficacy of drugs was examined in a mouse orthotopic xenograft model. Combined treatment of GBM TSs with HCA or BCA and TMZ significantly reduced cell viability, stemness, and invasiveness. Expression levels of stemness-, invasiveness-, and mesenchymal transition-associated markers, Zeb1, N-cadherin, and β-catenin, were also substantially decreased by the combined treatment. The combined treatment also reduced tumor growth in a mouse orthotopic xenograft model. Our findings suggest that HCA and BCA, combined with TMZ, are potential therapeutic agents in the treatment of GBM.

Combined inhibition of RAC1 and Bcl-2/Bcl-xL synergistically induces glioblastoma cell death through down-regulation of the Usp9X/Mcl-1 axis.

Anti-apoptotic and pro-migratory phenotypes are hallmarks of neoplastic diseases, including primary brain malignancies. In this work, we examined whether reprogramming of the apoptotic and migratory machineries through a multi-targeting approach would induce enhanced cell death and enhanced inhibition of the migratory capacity of glioblastoma cells. Preclinical testing and molecular analyses of combined inhibition of Bcl-2/Bcl-xL and RAC1 were performed in established, primary cultured and stem-like glioblastoma cell systems. We found that the combined inhibition of Bcl-2/Bcl-xL and RAC1 resulted in synergistic pro-apoptotic and anti-migratory effects in a broad range of different glioblastoma cells. At the molecular level, we found that RAC1 inhibition led to a decreased expression of the deubiquitinase Usp9X, followed by a decreased stability of Mcl-1. We also found that the combined inhibition led to a significantly decreased migratory activity and that tumor formation of glioblastoma cells on chorion allantoic membranes of chicken embryos was markedly impaired following the combined inhibition. Our data indicate that concomitant inhibition of RAC1 and Bcl-2/Bcl-xL induces pro-apoptotic and anti-migratory glioblastoma phenotypes as well as synergistic anti-neoplastic activities. The clinical efficacy of this inhibitory therapeutic strategy warrants further evaluation.

Malignant primary brain and other central nervous system tumors diagnosed in Canada from 2009 to 2013.

BackgroundWe present a national surveillance report on malignant primary brain and other central nervous system (CNS) tumors diagnosed in the Canadian population in 2009–2013.MethodsPatients were identified through the Canadian Cancer Registry, an administrative dataset that includes cancer incidence data from all provinces/territories in Canada. Tumor types were classified by site and histology using the definitions from the Central Brain Tumor Registry of the United States (CBTRUS). Incidence rates (IRs) and 95% confidence intervals (CIs) were calculated per 100000 person-years (py) and age-standardized to the 2011 Canadian population for comparisons within Canada and to the 2000 United States population for comparisons with the US.ResultsOverall, 12515 malignant brain and other CNS tumors were diagnosed in the Canadian population in 2009–2013 (IR: 8.71/100000 py; 95% CI: 8.56, 8.86); 7085 were among males (IR: 10.06/100000 py; 95% CI: 9.82, 10.29) and 5430 among females (IR: 7.41/100000 py; 95% CI: 7.22, 7.61). Of these, 12115 were classifiable according to histological subgroups defined by CBTRUS. The most common histology was glioblastoma (IR: 4.06/100000 py; 95% CI: 3.95, 4.16). Among those aged 0–19 years, 1130 malignant brain and CNS tumors were diagnosed in 2009–2013 (IR: 3.36/100000 py; 95% CI: 3.16, 3.56). The most common histology among the pediatric population was embryonal tumor (IR: 0.74/100000 py; 95% CI: 0.65, 0.84).ConclusionsThese data represent an initial detailed report on the frequency and distribution of primary malignant brain and other CNS tumors diagnosed in the Canadian population in 2009–2013. The reported distributions of tumor diagnoses by sex and age reflected expected patterns based on the literature from similar populations. A report incorporating data on nonmalignant primary brain tumors is forthcoming.

Differential Exosomic Proteomic Patterns and Their Influence in Resveratrol Sensitivities of Glioblastoma Cells.

Glioblastoma multiforme (GBM) is the commonest primary brain malignancy with extremely poor prognosis. Resveratrol posseses anti-cancer effects, while GBM cells respond differently to it due to certain unknown reason(s). Because the tumor-derived exosomes are supposed to influence chemosensitivity, the exosomic proteins released from resveratrol-sensitive U251 and resveratrol-resistant glioblastoma LN428 cells are profiled before (N/Exo) and after drug treatment (Res/Exo) by label-free liquid chromatography-mass spectrometry (LC-MS). The therapeutic implications of the proteomic findings are estimated by gene ontology enrichment analysis (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG)-based bioinformatic analyses and further elucidated by exosome co-incubating. The results reveal that U251/N/Exo but not U251/Res/Exo enhances resveratrol sensitivity of resveratrol-resistant LN428 cells. The resveratrol sensitive properties of U251 cells are not altered by either LN428/N/Exo or LN428/Res/Exo. U251/N/Exo contains higher levels of chromatin silencing and epidermis development proteins, while U251/Res/Exo has more oxygen transport and G protein-coupled receptor. Both of LN428/N/Exo and LN428/Res/Exo are rich in the proteins related with nucleosome assembly, microtubule-based process and chromatin silencing. In conclusion, U251/N/Exo sensitizes LN428 cells to resveratrol via delivering drug sensitizing signals, suggesting the presence of additional factor(s) that may determine the resveratrol sensitivities of glioblastoma cells.

I6P7 peptide modified superparamagnetic iron oxide nanoparticles for magnetic resonance imaging detection of low-grade brain gliomas.

Glioma, the most severe primary brain malignancy, has very low survival rates and a high level of recurrence. Nowadays, conventional treatments for these patients are suffering a similar plight owing to the distinctive features of the malignant gliomas, for example chemotherapy is limited by the blood-brain barrier while surgery and radiation therapy are affected by the unclear boundaries of tumor from normal tissue. In the present study, a novel superparamagnetic iron oxide (SPIO) nanoprobe for enhanced T2-weighted magnetic resonance imaging (MRI) was developed. A frequently used MRI probe, SPIO nanoparticles, was coated with a silica outer layer and for the first time was covalently modified with interleukin-6 receptor targeting peptides (I6P7) to promote transportation through the blood-brain barrier and recognition of low-grade gliomas. The efficiency of transcytosis across the blood-brain barrier was examined in vitro using a transwell invasion model and in vivo in nude mice with orthotopic low-grade gliomas. The targeting nanoprobe showed significant MRI enhancement and has potential for use in the diagnosis of low-grade gliomas.

Arterial and Venous Thromboembolic Safety of Bevacizumab in Patients with High Grade Gliomas

INTRODUCTIONBevacizumab, an angiogenesis inhibitor targeting vascular endothelial growth factor A, is used for the treatment of recurrent glioblastoma, the most common primary brain malignancy in adults. Multiple studies demonstrate the efficacy of bevacizumab on progression-free and overall survival of patients with recurrent glioblastoma. However, real world safety data of bevacizumab in patients with glioblastoma is limited on serious adverse outcomes including arterial and venous thrombosis. Our study aimed to evaluate the risk of arterial thromboembolism (ATE) and venous thromboembolism (VTE) in a population-based sample of adult patients with high grade gliomas.METHODWe conducted a nested case-control study within a retrospective cohort of patients receiving treatment for high grade gliomas under the protocol by Stupp, et al. (radiotherapy plus concomitant/adjuvant temezolomide). Patients were sampled from the Truven Health MarketScan® Research Database, containing administrative health claims data of over 40 million commercially insured enrollees and their dependents, between 2009 and 2015. A validated algorithm was used to identify patients with high grade gliomas that underwent craniotomy (index time) with external beam radiation and temozolomide-based treatment occurring within 91 days (cohort entry time). Patients were excluded if they received craniotomy, radiation, temozolomide or bevacizumab during year prior to surgery or had one of our outcomes of interest (ATE or VTE) during the cohort ascertainment period (between index and cohort entry dates). Patients were required to have continuous health plan enrollment during the 12-month baseline and follow up periods (unless died). Surgical procedures and chemotherapy treatments were identified using diagnostic and procedural medical and pharmacy claims data. These data sources were also used to identify VTE risk factors, including medical conditions, procedures and medication use, and to calculate modified Charlson comorbidity index scores at baseline.Cases of ATE and VTE were each identified in the overall cohort using a validated algorithm for administrative claims data. For ATE and VTE separately, each case was matched to up to ten controls on sex, age group, index time and follow-up duration using incidence density sampling with replacement. Exposure to bevacizumab was characterized as any use (yes vs. no) and recent use (last bevacizumab infusion within 30 days prior event or control censoring). We estimated relative risk of ATE and VTE associated with bevacizumab in separate models using conditional logistic regression models to calculate adjusted odds ratios (aOR) and 95% confidence interval (CI). All multivariable models were adjusted for sex, age, and comorbidity index scores; models for risk of VTE were also adjusted for number of baseline VTE risk factors and VTE prophylaxis received.RESULTSOur final study cohort included 2157 patients undergoing treatment for high grade gliomas. We identified 25 ATE cases and 99 VTE cases and matched incidence density-sampled controls (n=170 for ATE; n=819 for VTE) for our nested case-control analysis. A higher proportion of ATE cases received bevacizumab during follow up compared to the controls (28% vs. 17%). In multivariable analyses, no statistically significant increase in ATE risk was observed with bevacizumab overall (aOR 1.51, 95% CI 0.54-4.24), although confidence intervals were wide given the few events observed. Compared to controls in the VTE analysis, cases had a slightly higher proportion of baseline VTE risk factors (2 or more: 17% vs. 13%) and treatment with bevacizumab (13% vs. 9%). However, we found no significant increased risk of VTE associated with bevacizumab overall (aOR 1.40, 95% CI 0.71-2.75) or recent infusion of bevacizumab (aOR 1.40, 95% CI 0.65-3.01).CONCLUSIONSOur findings from this large retrospective cohort of patients undergoing treatment for high grade glioma provide little evidence in support of the increased risk of ATE and VTE reported with use of bevacizumab in other cancer sites. Our study was limited by an overall small number of ATE events observed, and further research is needed to confirm safety of bevacizumab with respect to arterial thrombosis. These population-based estimates show no significant increase in risk of VTE associated with bevacizumab and suggest its safe use in the treatment of high grade gliomas. DisclosuresLee:AbbVie Inc.: Research Funding. Patel:Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Honoraria.

Rapid discrimination of pediatric brain tumors by mass spectrometry imaging

PurposeMedulloblastoma, the most common primary pediatric malignant brain tumor, originates in the posterior fossa of the brain. Pineoblastoma, which originates within the pineal gland, is a rarer malignancy that also presents in the pediatric population. Medulloblastoma and pineoblastoma exhibit overlapping clinical features and have similar histopathological characteristics. Histopathological similarities confound rapid diagnoses of these two tumor types. We have conducted a pilot feasibility study analyzing the molecular profile of archived frozen human tumor specimens using mass spectrometry imaging (MSI) to identify potential biomarkers capable of classifying and distinguishing between medulloblastoma and pineoblastoma.MethodsWe performed matrix-assisted laser desorption ionization Fourier transform ion cyclotron resonance mass spectrometry imaging on eight medulloblastoma biopsy specimens and three pineoblastoma biopsy specimens. Multivariate statistical analyses were performed on the MSI dataset to generate classifiers that distinguish the two tumor types. Lastly, the molecules that were discriminative of tumor type were queried against the Lipid Maps database and identified.ResultsIn this pilot study we show that medulloblastoma and pineoblastoma can be discriminated using molecular profiles determined by MSI. The highest-ranking discriminating classifiers of medulloblastoma and pineoblastoma were glycerophosphoglycerols and sphingolipids, respectively.ConclusionWe demonstrate proof-of-concept that medulloblastoma and pineoblastoma can be rapidly distinguished by using MSI lipid profiles. We identified biomarker candidates capable of distinguishing these two histopathologically similar tumor types. This work expands the current molecular knowledge of medulloblastoma and pineoblastoma by characterizing their lipidomic profiles, which may be useful for developing novel diagnostic, prognostic and therapeutic strategies.

Combined c-Met/Trk Inhibition Overcomes Resistance to CDK4/6 Inhibitors in Glioblastoma.

Glioblastoma (GBM) is the most common primary brain malignancy and carries an extremely poor prognosis. Recent molecular studies revealed the CDK4/6-Rb-E2F axis and receptor tyrosine kinase (RTK) signaling to be deregulated in most GBM, creating an opportunity to develop more effective therapies by targeting both pathways. Using a phospho-RTK protein array, we found that both c-Met and TrkA-B pathways were significantly activated upon CDK4/6 inhibition in GBM cells. We therefore investigated the efficacy of combined CDK4/6 and c-Met/TrkA-B inhibition against GBM. We show that both c-Met and TrkA-B pathways transactivate each other, and targeting both pathways simultaneously results in more efficient pathway suppression. Mechanistically, inhibition of CDK4/6 drove NF-κB-mediated upregulation of hepatocyte growth factor, brain-derived neurotrophic factor, and nerve growth factor that in turn activated both c-Met and TrkA-B pathways. Combining the CDK4/6 inhibitor abemaciclib with the c-Met/Trk inhibitor altiratinib or the corresponding siRNAs induced apoptosis, leading to significant synergy against GBM. Collectively, these findings demonstrate that the activation of c-Met/TrkA-B pathways is a novel mechanism involved in therapeutic resistance of GBM to CDK4/6 inhibition and that dual inhibition of c-Met/Trk with CDK4/6 should be considered in future clinical trials.Significance: CDK4/6 inhibition in glioblastoma activates the c-Met and TrkA-B pathways mediated by NF-κB and can be reversed by a dual c-Met/Trk inhibitor. Cancer Res; 78(15); 4360-9. ©2018 AACR.

Abstract 1666: Novel glucose transporter inhibitors decrease glioblastoma growth and glucose uptake

Abstract Glioblastoma multiform (GBM) is the most common primary malignant adult brain tumor and one of the deadliest cancers. Patients with GBM typically undergo surgical resection, radiation and chemotherapy with temozolomide. Complete tumor resection is virtually impossible due to tumor location and the highly infiltrative nature of GBM, which leads to disease recurrence near the original tumor site. As such, these patients have a dramatically decreased life expectancy. Therapeutic development to prolong survival has been hampered by a high degree of inter- and intra-tumoral heterogeneity. Contributing to tumor heterogeneity is a subset of highly tumorigenic cells, termed brain tumor initiating cells (BTICs), that are able to self-renew and can be highly invasive and therapy resistant. BTICs are often enriched in perinecrotic regions, a GBM hallmark, where they can survive under nutrient restriction via increased glucose transporter 3 expression (GLUT3). GLUT3 has a 5-fold greater capacity for glucose transport than the other major glucose transporter isoform in the brain, GLUT1, and is typically restricted to neurons, testis, preimplantation embryos, and stem cells. GLUT3 expression is elevated in many solid tumor types, including GBM, and correlates with poor patient prognosis. Previously, we have shown that knockdown of GLUT3 in BTICs significantly inhibits their growth both in vitro and in vivo, indicating GLUT3 is a possible target for therapeutic intervention. Using structure based virtual screening, we have identified novel GLUT inhibitors that preferentially decrease the growth and glucose uptake of BTICs with minimal toxicity to non-malignant cells in vitro. Preliminary in vivo assessment of these compounds has not indicated toxicity. Our goal is to identify a potential new therapeutic option targeting metabolic reprogramming for the treatment of glioblastoma, as well as other tumor types. Citation Format: Catherine J. Libby, Sixue Zhang, Gloria A. Benavides, Yanjie Li, Matthew Redmann, Anh N. Tran, Arphaxad Otamias, Victor Darley-Usmar, Marek Napierala, Jianhua Zhang, Wei Zhang, Anita Hjelmeland. Novel glucose transporter inhibitors decrease glioblastoma growth and glucose uptake [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1666.

Abstract 1424: Elucidating the microRNA-203 specific biological processes in glioblastoma cells from high-throughput RNA-sequencing

Abstract Glioblastoma (GBM) is the most common primary malignant intracranial adult brain tumor. Allelic deletion on chromosome 14q play an essential role in GBM pathogenesis, and this chromosome 14q site was thought to harbor multiple tumor suppressor gene associated with GBM, a region that also encodes microRNA-203 (miR-203). This study was conducted to identify gene expression profile changes associated with mir-203 expression by high-throughput RNA sequencing. Enrichment analyses for gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis revealed that mir-203 expression had a strong, negative effect on a number of fundamental and interconnected biological processes involved in cell growth and proliferation. The biological processes mostly influenced were p53 signaling pathway, FoxO signaling pathway, DNA replication, cell cycle, MAPK signaling pathway and Apoptosis. In total, 847 upregulated and 345 downregulated differentially expressed genes (DEGs) were identified in control versus miR203 expressing glioma cells. After GO enrichment, the downregulated DEGs and miR-203 predicted target genes such as BCL-2, SPARC, PDGFA, CREB were found to be mainly enriched in cell cycle regulation and apoptosis processes, whereas the upregulated DEGs, such as CCND1, E2F1 were involved in the DNA replication and cell cycle regulation of gene expression. We also demonstrate that mir-203 expression suppressed BCL-2 protein and mRNA by western blotting and qRT-PCR analysis. Moreover, co-transfection experiments using a luciferase-based reporter assay demonstrated that mir-203 directly regulated BCL-2 expression and BCL-2 overexpression suppressed mir-203 mediated cell death. Knowledge gained through this profiling study can facilitate targeted therapeutic interventions. Citation Format: Bhavesh K. Ahir, Herbert H. Engelhard, Sajani S. Lakka. Elucidating the microRNA-203 specific biological processes in glioblastoma cells from high-throughput RNA-sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1424.

Development of a prognostic model for glioblastoma patients treated with standard therapy: A prospective study from a single institution.

e14086Background: Glioblastoma is the most malignant and lethal primary brain tumor. Standard therapy comprises maximal safe surgical resection, radiation therapy plus concomitant and adjuvant temo...

Potent Antitumour Effects of Novel Pentabromobenzylisothioureas Studied on Human Glial-derived Tumour Cell Lines.

Tumours of astroglial origin are the most common primary brain malignancy characterized by infiltrative growth and resistance to standard antitumour therapy. Glioma progression is thought to be related to various intracellular signal transduction pathways that involve the activation of protein kinases. Protein kinases play important roles in cell differentiation, proliferation, and survival. Recently, novel, specific inhibitors of constitutively active serine/threonine kinases and structurally similar isothiourea derivatives were suggested to induce apoptosis and inhibit proliferation in several types of human cancer cells. In this study, we examined the cytotoxic and proapoptotic activities of selected modified pentabromobenzyl isothioureas (ZKKs) in an adult human glioblastoma (T98G) and a subependymal giant cell astrocytoma cell (SEGA) line. We evaluated cell proliferation, viability, and apoptosis. Two pentabromobenzyl isothiourea bromide derivatives, ZKK-13 and N,N,N'-trimethyl-ZKK1 (TRIM), exhibited the most potent cytotoxic and proapoptotic efficacies against human glioma-derived cells, even at a very low concentration (1 μM). ZKK-13 (25-50 μM) inhibited cell growth by approximately 80-90% in 24 and 48 h of treatment. We showed that selected ZKKs exerted antiproliferative activity against astroglial neoplastic cells of both low- and high-grade tumour malignancy classes. No synergistic effects were detected when ZKKs were combined with serine/threonine kinase inhibitors. Our findings indicated that modified ZKKs show promise for the treatment of glioma-derived brain tumours.

Assessment of psychological distress among Asian adolescents and young adults (AYA) cancer patients using the distress thermometer: a prospective, longitudinal study.

Since few studies have investigated whether the Distress Thermometer (DT) in Asian adolescent and young adult (AYA) cancer patients (between 15 and 39years), we investigated the appropriateness of the DT as a screening tool for psychological symptom burden in these AYA patients and to evaluate AYA patients' distress across a trajectory of three time points longitudinally over a 6-month period. This was a prospective, longitudinal study. Recruited Asian AYA patients were diagnosed with lymphomas, sarcomas, primary brain malignancies, or germ cell tumors. Patients completed the DT, PedsQL Generic Core Scales, and the Rotterdam Symptom Checklist. Data were analyzed using STATA version 15. Approximately half of the patients experienced clinically significant DT distress (distress score ≥ 4) early in their cancer journey with 43.1% patients presenting with distress at time of diagnosis and 47.7% patients 1month after diagnosis. Among AYA patients > 24years old, worry (68.3%), insurance/financial issues (61%), treatment decisions (43.9%), work/school issues (41.5%), nervousness (41.5%), and sadness (41.5%) were the top five identified problems. On the other hand, the top five identified problems among AYA ≤ 24 years were worry (54.2%), nervousness (41.7%), bathing/dressing problems (37.5%), work/school issues (33.3%), and fatigue (33.3%). DT scores were significantly associated with certain psychological symptom burden items such as worry (p < 0.001), depressed mood (p = 0.020), and nervousness (p = 0.015). The DT is a useful screening tool for psychological distress in AYA cancer patients with clinically significant distress being identified in the early phases of the cancer journey.