bims-malgli 2021-10-10 papers

bims-malgli

Biomed News

on Biology of malignant gliomas

Issue of 2021–10–10
nineteen papers selected by
Oltea Sampetrean, Keio University

Transcription Elongation Machinery Is a Druggable Dependency and Potentiates Immunotherapy in Glioblastoma Stem Cells.
The aryl hydrocarbon receptor: a diagnostic and therapeutic target in glioma.
Hydrogen sulfide operates as a glioblastoma suppressor and is lost under high fat diet.
Subventricular zone involvement is associated with worse outcome in glioma WHO grade 2 depending on molecular markers.
Identification of Rac guanine nucleotide exchange factors promoting Lgl1 phosphorylation in glioblastoma.
BRAF mutations may identify a clinically distinct subset of glioblastoma.
Intracranially injectable multi-siRNA nanomedicine for the inhibition of glioma stem cells.
Glioblastoma patient-derived cell-based phenotypic drug screening and identification of possible action mechanisms through proteomic analysis.
Targeting EYA2 tyrosine phosphatase activity in glioblastoma stem cells induces mitotic catastrophe.
Oncogenic activity of glucocorticoid receptor β is controlled by ubiquitination-dependent interaction with USP49 in glioblastoma cells.
Functional drug susceptibility testing using single-cell mass predicts treatment outcome in patient-derived cancer neurosphere models.
DHHC9-mediated GLUT1 S-palmitoylation promotes glioblastoma glycolysis and tumorigenesis.
Avelumab in newly diagnosed glioblastoma.
Identification of Gender-Specific Molecular Differences in Glioblastoma (GBM) and Low-Grade Glioma (LGG) by the Analysis of Large Transcriptomic and Epigenomic Datasets.
The EGFRvIII transcriptome in glioblastoma, a meta-omics analysis.
Etched in Code: Revisiting glioma risk factors through the exome.
An oncolytic virus expressing a full-length antibody enhances antitumor innate immune response to glioblastoma.
A Systematic Review of the Tumor-Infiltrating CD8+ T-Cells/PD-L1 Axis in High-Grade Glial Tumors: Toward Personalized Immuno-Oncology.
CBTRUS Statistical Report: Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2014-2018.

Cancer Discov. 2021 Oct 06. pii: candisc.1848.2020. [Epub ahead of print]

Transcription Elongation Machinery Is a Druggable Dependency and Potentiates Immunotherapy in Glioblastoma Stem Cells.

Zhixin Qiu, Linjie Zhao, Jia Z Shen, Zhengyu Liang, Qiulian Wu, Kailin Yang, Lihua Min, Ryan C Gimple, Qiyuan Yang, Shruti Bhargava, Chunyu Jin, Cheryl Kim, Denise Hinz, Deobrat Dixit, Jean A Bernatchez, Briana C Prager, Guoxin Zhang, Zhen Dong, Deguan Lv, Xujun Wang, Leo J Y Kim, Zhe Zhu, Katherine A Jones, Ye Zheng, Xiuxing Wang, Jair L Siqueira-Neto, Lukas Chavez, Xiang-Dong Fu, Charles Spruck, Jeremy N Rich.

Glioblastoma (GBM) is the most lethal primary brain cancer characterized by therapeutic resistance, which is promoted by GBM stem cells (GSCs). Here, we interrogated gene expression and whole genome CRISPR/Cas9 screening in a large panel of patient-derived GSCs, differentiated glioblastoma cells (DGCs), and neural stem cells (NSCs) to identify master regulators of GSC stemness, revealing an essential transcription state with increased RNA polymerase II-mediated transcription. The YY1 and transcriptional CDK9 complex was essential for GSC survival and maintenance in vitro and in vivo. YY1 interacted with CDK9 to regulate transcription elongation in GSCs. Genetic or pharmacological targeting of YY1-CDK9 complex elicited RNA m6A modification-dependent interferon responses, reduced regulatory T cell infiltration, and augmented efficacy of immune checkpoint therapy in glioblastoma. Collectively, these results suggest that YY1-CDK9 transcription elongation complex defines a targetable cell state with active transcription, suppressed interferon responses, and immunotherapy resistance in glioblastoma.

DOI: https://doi.org/10.1158/2159-8290.CD-20-1848
Drug Discov Today. 2021 Oct 05. pii: S1359-6446(21)00427-X. [Epub ahead of print]

The aryl hydrocarbon receptor: a diagnostic and therapeutic target in glioma.

Ting Xiang Lim, Muneer Ahamed, David C Reutens.

  Glioblastoma multiforme (GBM) is a deadly disease; 5-year survival rates have shown little improvement over the past 30 years. In vivo positron emission tomography (PET) imaging is an important method of identifying potential diagnostic and therapeutic molecular targets non-invasively. The aryl hydrocarbon receptor (AhR) is a transcription factor that regulates multiple genes involved in immune response modulation and tumorigenesis. The AhR is an attractive potential drug target and studies have shown that its activation by small molecules can modulate innate and adaptive immunity beneficially and prevent AhR-mediated tumour promotion in several cancer types. In this review, we provide an overview of the role of the AhR in glioma tumorigenesis and highlight its potential as an emerging biomarker for glioma therapies targeting the tumour immune response and PET diagnostics.

Keywords:  AhR; GBM; PET imaging; biomarker; immunotherapy

DOI:  https://doi.org/10.1016/j.drudis.2021.09.021
Mol Cell Oncol. 2021 ;8(4): 1973312

Hydrogen sulfide operates as a glioblastoma suppressor and is lost under high fat diet.

Daniel J Silver, Justin D Lathia, Christopher Hine.

  Glioblastoma (GBM) is one of the deadliest and aggressive forms of brain cancer. Environmental and intrinsic factors such as Western Diet and advanced age can function as powerful accelerants to the progression of GBM. Recently, we discovered that pre-clinical GBM models subject to an obesogenic and age-accelerating high fat diet (HFD) presented with hyperaggressive GBM phenotypes, including treatment-refractory cancer stem cell (CSC) enrichment. Mechanistically, HFD suppressed production of the gasotransmitter hydrogen sulfide (H2S) and its downstream sulfhydration signaling in the brain. Likewise, we observed dramatic loss of sulfhydration in brains of GBM patients. Importantly, we showed the tumor suppressive effects of H2S against GBM in cell culture and in vivo. Here, we discuss these recent findings and provide insight into how they can be leveraged to improve treatment modalities, prognosis, and quality of life for GBM patients.

Keywords:  Glioblastoma (GBM); cancer stem cells (CSCS); cystathionine beta-synthase (CBS); cystathionine gamma-lyase (CGL); high fat diet (HFD); hydrogen sulfide (H2S); mercaptopyruvate sulfurtransferase (MPST); oleic acid (OA); sry transcription factor 2 (SOX2); sulfhydration; transsulfuration

DOI:  https://doi.org/10.1080/23723556.2021.1973312
Sci Rep. 2021 Oct 08. 11(1): 20045

Subventricular zone involvement is associated with worse outcome in glioma WHO grade 2 depending on molecular markers.

Philipp Karschnia, Jonathan Weller, Jens Blobner, Veit M Stoecklein, Mario M Dorostkar, Kai Rejeski, Robert Forbrig, Maximilian Niyazi, Louisa von Baumgarten, Jorg Dietrich, Joerg-Christian Tonn, Niklas Thon.

Neural stem cells within the subventricular zone were identified as cells of origin driving growth of high-grade gliomas, and anatomical involvement of the subventricular zone has been associated with an inferior clinical outcome. Whether the association between poor outcome and subventricular zone involvement also applies to glioma of lower grades is unclear. We therefore analysed a retrospective cohort of 182 patients with glioma grade 2 (according to the WHO 2016 classification) including 78 individuals (43%) with subventricular zone involvement. Patients with and without subventricular zone involvement did not differ in regard to demographics, histopathology, and molecular markers. Notably, subventricular zone involvement was a negative prognostic marker for malignant progression and overall survival on uni- and multivariate analysis. When patients were stratified according to the cIMPACT-NOW update 6, subventricular zone involvement was negatively associated with outcome in IDH-wildtype astrocytomas and 1p19q-codeleted oligodendrogliomas but not in IDH-mutant astrocytomas. Collectively, subventricular zone involvement may represent a risk factor for worse outcome in glioma WHO grade 2 depending on the molecular tumor signature. The present data confirm the relevance of molecular glioma classifications as proposed by the cIMPACT-NOW update 6. These findings warrant evaluation in prospective cohorts.

DOI: https://doi.org/10.1038/s41598-021-97714-5
J Biol Chem. 2021 Oct 05. pii: S0021-9258(21)00974-1. [Epub ahead of print] 101172

Identification of Rac guanine nucleotide exchange factors promoting Lgl1 phosphorylation in glioblastoma.

Sylvie J Lavictoire, Danny Jomaa, Alexander Gont, Karen Jardine, David P Cook, Ian Aj Lorimer.

  The protein Lgl1 is a key regulator of cell polarity. We previously showed that Lgl1 is inactivated by hyperphosphorylation in glioblastoma as a consequence of PTEN tumour suppressor loss and aberrant activation of the PI 3-kinase pathway; this contributes to glioblastoma pathogenesis both by promoting invasion and repressing glioblastoma cell differentiation. Lgl1 is phosphorylated by atypical protein kinase C that has been activated by binding to a complex of the scaffolding protein Par6 and active, GTP-bound Rac. The specific Rac guanine nucleotide exchange factors that generate active Rac to promote Lgl1 hyperphosphorylation in glioblastoma are unknown. We used CRISPR/Cas9 to knockout PREX1, a PI 3-kinase pathway-responsive Rac guanine nucleotide exchange factor, in patient-derived glioblastoma cells. Knockout cells had reduced Lgl1 phosphorylation which was reversed by re-expressing PREX1. They also had reduced motility and an altered phenotype suggestive of partial neuronal differentiation; consistent with this, RNA-seq analyses identified sets of PREX1-regulated genes associated with cell motility and neuronal differentiation. PREX1 knockout in glioblastoma cells from a second patient did not affect Lgl1 phosphorylation. This was due to overexpression of a short isoform of the Rac guanine nucleotide exchange factor TIAM1; knockdown of TIAM1 in these PREX1 knockout cells reduced Lgl1 phosphorylation. These data show that PREX1 links aberrant PI 3-kinase signaling to Lgl1 phosphorylation in glioblastoma, but that TIAM1 is also to fill this role in a subset of patients. This redundancy between PREX1 and TIAM1 is only partial, as motility was impaired in PREX1 knockout cells from both patients.

Keywords:  LLGL1; Lgl1; PREX1; TIAM1; cell differentiation; cell motility; cell polarity; glioblastoma; glioma; lethal giant larvae; phosphatidylinositol signaling

DOI:  https://doi.org/10.1016/j.jbc.2021.101172
Sci Rep. 2021 Oct 08. 11(1): 19999

BRAF mutations may identify a clinically distinct subset of glioblastoma.

Samantha N McNulty, Katherine E Schwetye, Cole Ferguson, Chad E Storer, George Ansstas, Albert H Kim, David H Gutmann, Joshua B Rubin, Richard D Head, Sonika Dahiya.

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Prior studies examining the mutational landscape of GBM revealed recurrent alterations in genes that regulate the same growth control pathways. To this regard, ~ 40% of GBM harbor EGFR alterations, whereas BRAF variants are rare. Existing data suggests that gain-of-function mutations in these genes are mutually exclusive. This study was designed to explore the clinical, pathological, and molecular differences between EGFR- and BRAF-mutated GBM. We reviewed retrospective clinical data from 89 GBM patients referred for molecular testing between November 2012 and December 2015. Differences in tumor mutational profile, location, histology, and survival outcomes were compared in patients with EGFR- versus BRAF-mutated tumors, and microarray data from The Cancer Genome Atlas was used to assess differential gene expression between the groups. Individuals with BRAF-mutant tumors were typically younger and survived longer relative to those with EGFR-mutant tumors, even in the absence of targeted treatments. BRAF-mutant tumors lacked distinct histomorphology but exhibited unique localization in the brain, typically arising adjacent to the lateral ventricles. Compared to EGFR- and IDH1-mutant tumors, BRAF-mutant tumors showed increased expression of genes related to a trophoblast-like phenotype, specifically HLA-G and pregnancy specific glycoproteins, that have been implicated in invasion and immune evasion. Taken together, these observations suggest a distinct clinical presentation, brain location, and gene expression profile for BRAF-mutant tumors. Pending further study, this may prove useful in the stratification and management of GBM.

DOI: https://doi.org/10.1038/s41598-021-99278-w
Neurooncol Adv. 2021 Jan-Dec;3(1):3(1): vdab104

Intracranially injectable multi-siRNA nanomedicine for the inhibition of glioma stem cells.

Cheripelil Abraham Manju, Kottarapat Jeena, Ranjith Ramachandran, Maneesh Manohar, Anna Mathew Ambily, Koythatta Meethalveedu Sajesh, Genekehal Siddaramana Gowd, Krishnakumar Menon, Keechilat Pavithran, Ashok Pillai, Shantikumar V Nair, Manzoor Koyakutty.

   Background: Nanoparticle siRNA-conjugates are promising clinical therapeutics as indicated by recent US-FDA approval. In glioma stem cells (GSC), multiple stemness associated genes were found aberrant. We report intracranially injectable, multi-gene-targeted siRNA nanoparticle gel (NPG) for the combinatorial silencing of 3 aberrant genes, thus inhibiting the tumorogenic potential of GSCs.
Methods: NPG loaded with siRNAs targeted against FAK, NOTCH-1, and SOX-2 were prepared by the self-assembly of siRNAs with protamine-hyaluronic acid combination. Electron microscopy, DLS, and agarose gel electrophoresis were used for the physicochemical characterization. Cell transfection and gene-silencing efficiency were studied using human mesenchymal stem cells and rat C6 glioma-derived GSCs. Neurosphere inhibition was tested in vitro using GSCs derived from C6 cell line and glioma patient samples. Patient-derived xenograft model and orthotopic rat glioma model were used to test the effect of NPG on in vivo tumorigenicity.
Results: The siRNA nanoparticles with an average size ~ 250 nm and ~ 95% loading efficiency showed cellular uptake in ~95.5% GSCs. Simultaneous gene silencing of FAK, NOTCH-1, and SOX-2 led to the inhibition of neurosphere formation by GSCs, whereas normal stem cells remained unaffected and retained neuronal differentiation capability. GBM PDX models manifested significant impairment in the tumorigenic potential of NPG treated GSCs. Intracranial injection of NPG inhibited tumor growth in orthotopic rat brain tumor model.
Conclusion: Intracranially injectable n-siRNA NPG targeted to multiple stem-cell signaling impairs glioma initiation capabilities of GSCs and inhibited tumor growth in vivo.

Keywords:  cancer stem cells; gene silencing; nanoparticle; neurosphere; self-assembly

DOI:  https://doi.org/10.1093/noajnl/vdab104
STAR Protoc. 2021 Dec 17. 2(4): 100849

Glioblastoma patient-derived cell-based phenotypic drug screening and identification of possible action mechanisms through proteomic analysis.

Young Eun Kim, Hyun Young Kim, Daeyoung Jung, Dukjin Kang, Do-Hyun Nam, Hye Jin Nam, Heeyeong Cho.

  Because glioblastoma (GBM) exhibits high heterogeneity, it is desirable to use patient-derived cells from the first stage of screening for GBM drug discovery. Here, we describe a protocol to culture patient-derived GBM cells on the extracellular matrix-coated plates to allow high-throughput screening. Further, we detail approaches to identify the mechanism of action (MOA) of the selected effective drug through proteomics. This protocol will be useful for researchers interested in drug screening and the MOA of drugs. For complete details on the use and execution of this protocol, please refer to Nam et al. (2021).

Keywords:  Cancer; Cell Biology; Cell culture; Cell-based Assays; High Throughput Screening; Mass Spectrometry; Protein Biochemistry; Proteomics

DOI:  https://doi.org/10.1016/j.xpro.2021.100849
J Exp Med. 2021 Nov 01. pii: e20202669. [Epub ahead of print]218(11):

Targeting EYA2 tyrosine phosphatase activity in glioblastoma stem cells induces mitotic catastrophe.

Guoxin Zhang, Zhen Dong, Ryan C Gimple, Arthur Wolin, Qiulian Wu, Zhixin Qiu, Lisa M Wood, Jia Z Shen, Li Jiang, Linjie Zhao, Deguan Lv, Briana C Prager, Leo J Y Kim, Xiuxing Wang, Lingdi Zhang, Ryan L Anderson, Jeffrey K Moore, Shideng Bao, Thomas H Keller, Grace Lin, Congbao Kang, Petra Hamerlik, Rui Zhao, Heide L Ford, Jeremy N Rich.

Glioblastoma ranks among the most lethal of primary brain malignancies, with glioblastoma stem cells (GSCs) at the apex of tumor cellular hierarchies. Here, to discover novel therapeutic GSC targets, we interrogated gene expression profiles from GSCs, differentiated glioblastoma cells (DGCs), and neural stem cells (NSCs), revealing EYA2 as preferentially expressed by GSCs. Targeting EYA2 impaired GSC maintenance and induced cell cycle arrest, apoptosis, and loss of self-renewal. EYA2 displayed novel localization to centrosomes in GSCs, and EYA2 tyrosine (Tyr) phosphatase activity was essential for proper mitotic spindle assembly and survival of GSCs. Inhibition of the EYA2 Tyr phosphatase activity, via genetic or pharmacological means, mimicked EYA2 loss in GSCs in vitro and extended the survival of tumor-bearing mice. Supporting the clinical relevance of these findings, EYA2 portends poor patient prognosis in glioblastoma. Collectively, our data indicate that EYA2 phosphatase function plays selective critical roles in the growth and survival of GSCs, potentially offering a high therapeutic index for EYA2 inhibitors.

DOI: https://doi.org/10.1084/jem.20202669
Mol Cancer Res. 2021 Oct 05. pii: molcanres.1068.2020. [Epub ahead of print]

Oncogenic activity of glucocorticoid receptor β is controlled by ubiquitination-dependent interaction with USP49 in glioblastoma cells.

Yaling Hu, Yingdi Jiang, Zhenhao Zhang, Jingjing Wang, Bo Zhang, Lingli Gong, Li Ji, Zhening Pu, Xusheng Yang, Jian Zou, Ying Yin.

Previous studies have demonstrated that glucocorticoid receptor β (GRβ) functions as an oncoprotein, regulating the malignant phenotypes and stem-like cells maintaining in human glioblastoma (GBM). Of the GR isoforms, GRβ and GRα are highly homologous, though the mechanism underlying the distinct functions of these two isoforms in GBM has not been clarified. Here by establishing a C-terminal deletion mutant, we determined that GRβ can be ubiquitinated. We also found that its C-terminal is essential for this ubiquitination. The mutation of a lysine to arginine at residue 733 (K733R) blocked the ubiquitination of GRβ, indicating that K733 is a key site for ubiquitination. Using K733R to establish non-ubiquitinated GRβ, we demonstrated that ubiquitination not only regulates the stability and nuclear translocation of GRβ, but is also a vital mechanism for its oncogenic functions in vitro and in vivo. Protein interaction assay further indicated that ubiquitin-specific protease 49 (USP49) is a GRβ-binding protein and the interaction depends on GRβ ubiquitination. USP49 knockdown resulted in a decrease of cell proliferation, invasion, and an increase of cell apoptosis. More importantly, USP49 knockdown increased ubiquitination and amplified the oncogenic effects of GRβ, confirming the decisive role of ubiquitination on GRβ carcinogenicity. Taken together, these findings established that ubiquitination is a vial process for GRβ the execution of oncogenic functions in GBM and that the K733 site is crucial for ubiquitination of GRβ. Implications: This work is the first identify of the activation GRβ by a single lysine point-mediated ubiquitination and proteasome degradation, which determines its oncogenic functions in GBM.

DOI: https://doi.org/10.1158/1541-7786.MCR-20-1068
Cell Rep. 2021 Oct 05. pii: S2211-1247(21)01247-X. [Epub ahead of print]37(1): 109788

Functional drug susceptibility testing using single-cell mass predicts treatment outcome in patient-derived cancer neurosphere models.

Max A Stockslager, Seth Malinowski, Mehdi Touat, Jennifer C Yoon, Jack Geduldig, Mahnoor Mirza, Annette S Kim, Patrick Y Wen, Kin-Hoe Chow, Keith L Ligon, Scott R Manalis.

  Functional precision medicine aims to match individual cancer patients to optimal treatment through ex vivo drug susceptibility testing on patient-derived cells. However, few functional diagnostic assays have been validated against patient outcomes at scale because of limitations of such assays. Here, we describe a high-throughput assay that detects subtle changes in the mass of individual drug-treated cancer cells as a surrogate biomarker for patient treatment response. To validate this approach, we determined ex vivo response to temozolomide in a retrospective cohort of 69 glioblastoma patient-derived neurosphere models with matched patient survival and genomics. Temozolomide-induced changes in cell mass distributions predict patient overall survival similarly to O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation and may aid in predictions in gliomas with mismatch-repair variants of unknown significance, where MGMT is not predictive. Our findings suggest cell mass is a promising functional biomarker for cancers and drugs that lack genomic biomarkers.

Keywords:  cancer; cell mass; cell size; functional drug susceptibility testing; glioblastoma

DOI:  https://doi.org/10.1016/j.celrep.2021.109788
Nat Commun. 2021 Oct 07. 12(1): 5872

DHHC9-mediated GLUT1 S-palmitoylation promotes glioblastoma glycolysis and tumorigenesis.

Zhenxing Zhang, Xin Li, Fan Yang, Chao Chen, Ping Liu, Yi Ren, Pengkai Sun, Zixiong Wang, Yongping You, Yi-Xin Zeng, Xinjian Li.

Glucose transporter GLUT1 is a transmembrane protein responsible for the uptake of glucose into the cells of many tissues through facilitative diffusion. Plasma membrane (PM) localization is essential for glucose uptake by GLUT1. However, the mechanism underlying GLUT1 PM localization remains enigmatic. We find that GLUT1 is palmitoylated at Cys207, and S-palmitoylation is required for maintaining GLUT1 PM localization. Furthermore, we identify DHHC9 as the palmitoyl transferase responsible for this critical posttranslational modification. Knockout of DHHC9 or mutation of GLUT1 Cys207 to serine abrogates palmitoylation and PM distribution of GLUT1, and impairs glycolysis, cell proliferation, and glioblastoma (GBM) tumorigenesis. In addition, DHHC9 expression positively correlates with GLUT1 PM localization in GBM specimens and indicates a poor prognosis in GBM patients. These findings underscore that DHHC9-mediated GLUT1 S-palmitoylation is critical for glucose supply during GBM tumorigenesis.

DOI: https://doi.org/10.1038/s41467-021-26180-4
Neurooncol Adv. 2021 Jan-Dec;3(1):3(1): vdab118

Avelumab in newly diagnosed glioblastoma.

Francois H Jacques, Garth Nicholas, Ian A J Lorimer, Victorine Sikati Foko, Jasmine Prevost, Nathalie Dumais, Katy Milne, Brad H Nelson, John Woulfe, Gerard Jansen, B Erik Apedaile.

   Background: Glioblastoma (GBM) is known to use both local and systemic immunosuppressive strategies. One such strategy is the expression of the immune checkpoint protein programmed cell death ligand-1 (PD-L1) by both tumor cells and tumor-associated immune cells. Recent phase III trials using IgG4 antibodies targeting PD-1, the ligand for PD-L1, failed to show any benefit. Avelumab is an IgG1 monoclonal antibody targeting PD-L1. In contrast to the previously tested immune checkpoint inhibitors, it can directly bind tumor cells and immune cells expressing PD-L1 and can induce antibody-dependent cellular cytotoxicity.
Methods: We conducted a single center, open label, phase II study where avelumab 10 mg/kg IV Q2W was added concurrently to the first monthly temozolomide cycle in patients with newly diagnosed GBM. Immunohistochemical analyses were performed on surgery samples. The primary objective was safety. Secondary objectives were efficacy outcomes according to the immunotherapy Response Assessment in Neuro Oncology criteria, progression free survival (PFS), and overall survival (OS). Exploratory objectives aimed at determining prognostic biomarkers.
Results: Thirty patients were started on therapy and two were lost to follow-up. Median follow-up time (reverse Kaplan-Meier) was 41.7 months (IQR: 28.3-43.4). Three (10.0%) patients had a related or possibly related treatment emergent adverse event that lead to transient or permanent discontinuation of avelumab. Eight (26.7%) patients had one or more immune-related adverse events, and 8 (26.7%) patients had an infusion-related reaction. The overall response rate was 23.3%, median PFS was 9.7 months, and the median OS was 15.3 months. No pretreatment biomarkers showed any predictive value.
Conclusions: The addition of avelumab to standard therapy in patients with GBM was not associated with any new safety signal. There was no apparent improvement in OS.
Trial Registration: NCT03047473 Registered February 9, 2017.

Keywords:  PD-L1; avelumab; glioblastoma; immune checkpoint inhibitor; phase II

DOI:  https://doi.org/10.1093/noajnl/vdab118
Front Oncol. 2021 ;11 699594

Identification of Gender-Specific Molecular Differences in Glioblastoma (GBM) and Low-Grade Glioma (LGG) by the Analysis of Large Transcriptomic and Epigenomic Datasets.

Md Tipu Khan, Bharat Prajapati, Simran Lakhina, Mridula Sharma, Sachin Prajapati, Kunzang Chosdol, Subrata Sinha.

  Differences in the incidence and outcome of glioma between males and females are well known, being more striking for glioblastoma (GB) than low-grade glioma (LGG). The extensive and well-annotated data in publicly available databases enable us to analyze the molecular basis of these differences at a global level. Here, we have analyzed The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases to identify molecular indicators for these gender-based differences by different methods. Based on the nature of data available/accessible, the transcriptomic profile was studied in TCGA by using DeSeq2 and in CGGA by T-test, after correction based. Only IDH1 wild-type tumors were studied in CGGA. Using weighted gene co-expression network analysis (WGCNA), network analysis was done, followed by the assessment of modular differential connectivity. Differentially affected signaling pathways were identified. The gender-based effects of differentially expressed genes on survival were determined. DNA methylation was studied as an indicator of gender-based epigenetic differences. The results clearly showed gender-based differences in both GB and LGG, whatever method or database was used. While there were differences in the results obtained between databases and methods used, some major signaling pathways such as Wnt signaling and pathways involved in immune processes and the adaptive immune response were common to different assessments. There was also a differential gender-based influence of several genes on survival. Also, the autosomal genes NOX, FRG1BP, and AL354714.2 and X-linked genes such as PUDP, KDM6A, DDX3X, and SYAP1 had differential DNA methylation and expression profile in male and female GB, while for LGG, these included autosomal genes such as CNIH3 and ANKRD11 and X-linked genes such as KDM6A, MAOB, and EIF2S3. Some, such as FGF13 and DDX3X, have earlier been shown to have a role in tumor behavior, though their dimorphic effects in males and females have not been identified. Our study thus identifies several crucial differences between male and female glioma, which could be validated further. It also highlights that molecular studies without consideration of gender can obscure critical elements of biology and emphasizes the importance of parallel but separate analyses of male and female glioma.

Keywords:  epigenetics; gender-specific analysis; glioblastoma multiforme; low-grade glioma (LGG); pathway analysis; survival analysis; transcriptomics; weighted gene co-expression network analysis (WGCNA)

DOI:  https://doi.org/10.3389/fonc.2021.699594
Neuro Oncol. 2021 Oct 05. pii: noab231. [Epub ahead of print]

The EGFRvIII transcriptome in glioblastoma, a meta-omics analysis.

Youri Hoogstrate, Santoesha A Ghisai, Maurice de Wit, Iris de Heer, Kaspar Draaisma, Job van Riet, Harmen J G van de Werken, Vincent Bours, Jan Buter, Isabelle Vanden Bempt, Marica Eoli, Enrico Franceschi, Jean-Sebastien Frenel, Thierry Gorlia, Monique C Hanse, Ann Hoeben, Melissa Kerkhof, Johan M Kros, Sieger Leenstra, Giuseppe Lombardi, Slávka Lukacova, Pierre A Robe, Juan M Sepulveda, Walter Taal, Martin Taphoorn, René M Vernhout, Annemiek M E Walenkamp, Colin Watts, Michael Weller, Filip Y F de Vos, Guido W Jenster, Martin van den Bent, Pim J French.

   BACKGROUND: EGFR is among the genes most frequently altered in glioblastoma, with exons 2-7 deletions (EGFRvIII) being amongst its most common genomic mutations. There are conflicting reports about its prognostic role and it remains unclear whether and how it differs in signalling compared with wildtype EGFR.
METHODS: To better understand the oncogenic role of EGFRvIII, we leveraged four large datasets into one large glioblastoma transcriptome dataset (n=741) alongside 81 whole-genome samples from two datasets.
RESULTS: The EGFRvIII/EGFR expression ratios differ strongly between tumours and ranges from 1% to 95%. Interestingly, the slope of relative EGFRvIII expression is near-linear, which argues against a more positive selection pressure than EGFR wildtype. An absence of selection pressure is also suggested by the similar survival between EGFRvIII positive and negative glioblastoma patients. EGFRvIII levels are inversely correlated with pan-EGFR (all wildtype and mutant variants) expression, which indicates that EGFRvIII has a higher potency in downstream pathway activation. EGFRvIII-positive glioblastomas have a lower CDK4 or MDM2 amplification incidence than EGFRvIII-negative (p=0.007), which may point towards crosstalk between these pathways. EGFRvIII-expressing tumours have an upregulation of 'classical' subtype genes compared to those with EGFR-amplification only (p=3.873e-6). Genomic breakpoints of the EGFRvIII deletions have a preference towards the 3' end of the large intron-1. These preferred breakpoints preserve a cryptic exon resulting in a novel EGFRvIII variant and preserve an intronic enhancer.
CONCLUSIONS: These data provide deeper insights into the complex EGFRvIII biology and provide new insights for targeting EGFRvIII mutated tumours.

Keywords:  Breakpoints; EGFR; EGFRvIII; RNA-seq; glioblastoma

DOI:  https://doi.org/10.1093/neuonc/noab231
Neuro Oncol. 2021 Oct 04. pii: noab233. [Epub ahead of print]

Etched in Code: Revisiting glioma risk factors through the exome.

Roy E Strowd.

DOI: https://doi.org/10.1093/neuonc/noab233
Nat Commun. 2021 Oct 08. 12(1): 5908

An oncolytic virus expressing a full-length antibody enhances antitumor innate immune response to glioblastoma.

Bo Xu, Lei Tian, Jing Chen, Jing Wang, Rui Ma, Wenjuan Dong, Aimin Li, Jianying Zhang, E Antonio Chiocca, Balveen Kaur, Mingye Feng, Michael A Caligiuri, Jianhua Yu.

Oncolytic herpes simplex virus-1 is capable of lysing tumor cells while alerting the immune system. CD47, in collaboration with SIRPα, represents an important immune checkpoint to inhibit phagocytosis by innate immune cells. Here we show locoregional control of glioblastoma by an oncolytic herpes virus expressing a full-length anti(α)-human CD47 IgG1 or IgG4 antibody. The antibodies secreted by the virus-infected glioblastoma cells block the CD47 'don't eat me' signal irrespective of the subclass; however, αCD47-IgG1 has a stronger tumor killing effect than αCD47-IgG4 due to additional antibody-dependent cellular phagocytosis by macrophages and antibody-dependent cellular cytotoxicity by NK cells. Intracranially injected αCD47-IgG1-producing virus continuously releases the respective antibody in the tumor microenvironment but not into systemic circulation; additionally, αCD47-IgG1-producing virus also improves the survival of tumor-bearing mice better than control oncolytic herpes virus combined with topical αCD47-IgG1. Results from immunocompetent mouse tumor models further confirm that macrophages, and to a lesser extent NK cells, mediate the anti-tumor cytotoxicity of antibody-producing oncolytic herpesviruses. Collectively, oncolytic herpes simplex virus-1 encoding full-length antibodies could improve immune-virotherapy for glioblastoma.

DOI: https://doi.org/10.1038/s41467-021-26003-6
Front Immunol. 2021 ;12 734956

A Systematic Review of the Tumor-Infiltrating CD8+ T-Cells/PD-L1 Axis in High-Grade Glial Tumors: Toward Personalized Immuno-Oncology.

Mahdi Abdoli Shadbad, Zahra Asadzadeh, Negar Hosseinkhani, Afshin Derakhshani, Nazila Alizadeh, Oronzo Brunetti, Nicola Silvestris, Behzad Baradaran.

  Based on preclinical findings, programmed death-ligand 1 (PD-L1) can substantially attenuate CD8+ T-cell-mediated anti-tumoral immune responses. However, clinical studies have reported controversial results regarding the significance of the tumor-infiltrating CD8+ T-cells/PD-L1 axis on the clinical picture and the response rate of patients with high-grade glial tumors to anti-cancer therapies. Herein, we conducted a systematic review according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statements to clarify the clinical significance of the tumor-infiltrating CD8+ T-cells/PD-L1 axis and elucidate the impact of this axis on the response rate of affected patients to anti-cancer therapies. Indeed, a better understanding of the impact of this axis on the response rate of affected patients to anti-cancer therapies can provide valuable insights to address the futile response rate of immune checkpoint inhibitors in patients with high-grade glial tumors. For this purpose, we systematically searched Scopus, Web of Science, Embase, and PubMed to obtain peer-reviewed studies published before 1 January 2021. We have observed that PD-L1 overexpression can be associated with the inferior prognosis of glioblastoma patients who have not been exposed to chemo-radiotherapy. Besides, exposure to anti-cancer therapies, e.g., chemo-radiotherapy, can up-regulate inhibitory immune checkpoint molecules in tumor-infiltrating CD8+ T-cells. Therefore, unlike unexposed patients, increased tumor-infiltrating CD8+ T-cells in anti-cancer therapy-exposed tumoral tissues can be associated with the inferior prognosis of affected patients. Because various inhibitory immune checkpoints can regulate anti-tumoral immune responses, the single-cell sequencing of the cells residing in the tumor microenvironment can provide valuable insights into the expression patterns of inhibitory immune checkpoints in the tumor micromovement. Thus, administrating immune checkpoint inhibitors based on the data from the single-cell sequencing of these cells can increase patients' response rates, decrease the risk of immune-related adverse events development, prevent immune-resistance development, and reduce the risk of tumor recurrence.

Keywords:  PD-L1; glioma; immune checkpoint; personalized medicine; single-cell sequencing; tumor microenvironment; tumor-infiltrating CD8+ T-cells; tumor-infiltrating lymphocytes

DOI:  https://doi.org/10.3389/fimmu.2021.734956
Neuro Oncol. 2021 Oct 05. 23(Supplement_3): iii1-iii105

CBTRUS Statistical Report: Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2014-2018.

Quinn T Ostrom, Gino Cioffi, Kristin Waite, Carol Kruchko, Jill S Barnholtz-Sloan.

The Central Brain Tumor Registry of the United States (CBTRUS), in collaboration with the CDC and NCI, is the largest population-based registry focused exclusively on primary brain and other central nervous system (CNS) tumors in the United States (US) and represents the entire US population. This report contains the most up-to-date population-based data on primary brain tumors available and supersedes all previous reports in terms of completeness and accuracy and is the first CBTRUS Report to provide the distribution of molecular markers for selected brain and CNS tumor histologies. All rates are age-adjusted using the 2000 US standard population and presented per 100,000 population. The average annual age-adjusted incidence rate (AAAIR) of all malignant and non-malignant brain and other CNS tumors was 24.25 (Malignant AAAIR=7.06, Non-malignant AAAIR=17.18). This overall rate was higher in females compared to males (26.95 versus 21.35) and non-Hispanics compared to Hispanics (24.68 versus 22.12). The most commonly occurring malignant brain and other CNS tumor was glioblastoma (14.3% of all tumors and 49.1% of malignant tumors), and the most common non-malignant tumor was meningioma (39% of all tumors and 54.5% of non-malignant tumors). Glioblastoma was more common in males, and meningioma was more common in females. In children and adolescents (age 0-19 years), the incidence rate of all primary brain and other CNS tumors was 6.21. An estimated 88,190 new cases of malignant and non-malignant brain and other CNS tumors are expected to be diagnosed in the US population in 2021 (25,690 malignant and 62,500 non-malignant). There were 83,029 deaths attributed to malignant brain and other CNS tumors between 2014 and 2018. This represents an average annual mortality rate of 4.43 per 100,000 and an average of 16,606 deaths per year. The five-year relative survival rate following diagnosis of a malignant brain and other CNS tumor was 66.9%, for a non-malignant brain and other CNS tumors the five-year relative survival rate was 92.1%.

DOI: https://doi.org/10.1093/neuonc/noab200