bims-malgli Biomed News
on Biology of malignant gliomas
Issue of 2020‒10‒18
fourteen papers selected by
Oltea Sampetrean
Keio University


  1. Cancers (Basel). 2020 Oct 11. pii: E2919. [Epub ahead of print]12(10):
    Król SK, Kaczmarczyk A, Wojnicki K, Wojtas B, Gielniewski B, Grajkowska W, Kotulska K, Szczylik C, Czepko R, Banach M, Kaspera W, Szopa W, Marchel A, Czernicki T, Kaminska B.
      Anti-tumour therapies eliminate proliferating tumour cells by induction of DNA damage, but genomic aberrations or transcriptional deregulation may limit responses to therapy. Glioblastoma (GBM) is a malignant brain tumour, which recurs inevitably due to chemo- and radio-resistance. Human RecQ helicases participate in DNA repair, responses to DNA damage and replication stress. We explored if a helicase RECQL4 contributes to gliomagenesis and responses to chemotherapy. We found upregulated RECQL4 expression in GBMs associated with poor survival of GBM patients. Increased levels of nuclear and cytosolic RECQL4 proteins were detected in GBMs on tissue arrays and in six glioma cell lines. RECQL4 was detected both in cytoplasm and mitochondria by Western blotting and immunofluorescence. RECQL4 depletion in glioma cells with siRNAs and CRISPR/Cas9 did not affect basal cell viability, slightly impaired DNA replication, but induced profound transcriptomic changes and increased chemosensitivity of glioma cells. Sphere cultures originated from RECQL4-depleted cells had reduced sphere forming capacity, stronger responded to temozolomide upregulating cell cycle inhibitors and pro-apoptotic proteins. RECQL4 deficiency affected mitochondrial network and reduced mitochondrial membrane polarization in LN18 glioblastoma cells. We demonstrate that targeting RECQL4 overexpressed in glioblastoma could be a new strategy to sensitize glioma cells to chemotherapeutics.
    Keywords:  RecQ helicases; drug sensitivity; gene knockdown; gliomas; proliferation
    DOI:  https://doi.org/10.3390/cancers12102919
  2. Cancers (Basel). 2020 Oct 13. pii: E2964. [Epub ahead of print]12(10):
    Liesche-Starnecker F, Mayer K, Kofler F, Baur S, Schmidt-Graf F, Kempter J, Prokop G, Pfarr N, Wei W, Gempt J, Combs SE, Zimmer C, Meyer B, Wiestler B, Schlegel J.
      Tumor heterogeneity is considered to be a hallmark of glioblastoma (GBM). Only more recently, it has become apparent that GBM is not only heterogeneous between patients (intertumoral heterogeneity) but more importantly, also within individual patients (intratumoral heterogeneity). In this study, we focused on assessing intratumoral heterogeneity. For this purpose, the heterogeneity of 38 treatment-naïve GBM was characterized by immunohistochemistry. Perceptible areas were rated for ALDH1A3, EGFR, GFAP, Iba1, Olig2, p53, and Mib1. By clustering methods, two distinct groups similar to subtypes described in literature were detected. The classical subtype featured a strong EGFR and Olig2 positivity, whereas the mesenchymal subtype displayed a strong ALDH1A3 expression and a high fraction of Iba1-positive microglia. 18 tumors exhibited both subtypes and were classified as "subtype-heterogeneous", whereas the areas of the other tumors were all assigned to the same cluster and named "subtype-dominant". Results of epigenomic analyses corroborated these findings. Strikingly, the subtype-heterogeneous tumors showed a clearly shorter overall survival compared to subtype-dominant tumors. Furthermore, 21 corresponding pairs of primary and recurrent GBM were compared, showing a dominance of the mesenchymal subtype in the recurrent tumors. Our study confirms the prognostic impact of intratumoral heterogeneity in GBM, and more importantly, makes this hallmark assessable by routine diagnostics.
    Keywords:  glioblastoma; glioma; heterogeneity; immunohistochemistry; methylation assay; molecular pathology; prognostic marker; relapse; therapy resistance
    DOI:  https://doi.org/10.3390/cancers12102964
  3. Cancers (Basel). 2020 Oct 14. pii: E2973. [Epub ahead of print]12(10):
    Ammer LM, Vollmann-Zwerenz A, Ruf V, Wetzel CH, Riemenschneider MJ, Albert NL, Beckhove P, Hau P.
      Glioblastoma (GBM) is the most fatal primary brain cancer in adults. Despite extensive treatment, tumors inevitably recur, leading to an average survival time shorter than 1.5 years. The 18 kDa translocator protein (TSPO) is abundantly expressed throughout the body including the central nervous system. The expression of TSPO increases in states of inflammation and brain injury due to microglia activation. Not least due to its location in the outer mitochondrial membrane, TSPO has been implicated with a broad spectrum of functions. These include the regulation of proliferation, apoptosis, migration, as well as mitochondrial functions such as mitochondrial respiration and oxidative stress regulation. TSPO is frequently overexpressed in GBM. Its expression level has been positively correlated to WHO grade, glioma cell proliferation, and poor prognosis of patients. Several lines of evidence indicate that TSPO plays a functional part in glioma hallmark features such as resistance to apoptosis, invasiveness, and proliferation. This review provides a critical overview of how TSPO could regulate several aspects of tumorigenesis in GBM, particularly in the context of the hallmarks of cancer proposed by Hanahan and Weinberg in 2011.
    Keywords:  TSPO; diagnostic marker; glioblastoma; hallmarks of cancer
    DOI:  https://doi.org/10.3390/cancers12102973
  4. Oncogene. 2020 Oct 10.
    Lattier JM, De A, Chen Z, Morales JE, Lang FF, Huse JT, McCarty JH.
      Glioblastoma (GBM), or grade IV astrocytoma, is a malignant brain cancer that contains subpopulations of proliferative and invasive cells that coordinately drive primary tumor growth, progression, and recurrence after therapy. Here, we have analyzed functions for megalencephalic leukoencephalopathy with subcortical cysts 1 (Mlc1), an eight-transmembrane protein normally expressed in perivascular brain astrocyte end feet that is essential for neurovascular development and physiology, in the pathogenesis of GBM. We show that Mlc1 is expressed in human stem-like GBM cells (GSCs) and is linked to the development of primary and recurrent GBM. Genetically inhibiting MLC1 in GSCs using RNAi-mediated gene silencing results in diminished growth and invasion in vitro as well as impaired tumor initiation and progression in vivo. Biochemical assays identify the receptor tyrosine kinase Axl and its intracellular signaling effectors as important for MLC1 control of GSC invasive growth. Collectively, these data reveal key functions for MLC1 in promoting GSC growth and invasion, and suggest that targeting the Mlc1 protein or its associated signaling effectors may be a useful therapy for blocking tumor progression in patients with primary or recurrent GBM.
    DOI:  https://doi.org/10.1038/s41388-020-01503-9
  5. Cancers (Basel). 2020 Oct 13. pii: E2960. [Epub ahead of print]12(10):
    Manini I, Caponnetto F, Dalla E, Ius T, Pepa GMD, Pegolo E, Bartolini A, Rocca G, Menna G, Loreto CD, Olivi A, Skrap M, Sabatino G, Cesselli D.
      The glioblastoma microenvironment plays a substantial role in glioma biology. However, few studies have investigated its spatial heterogeneity. Exploiting 5-ALA Fluorescence Guided Surgery (FGS), we were able to distinguish between the tumor core (ALA+), infiltrating area (ALA-PALE) and healthy tissue (ALA-) of the glioblastoma, based on the level of accumulated fluorescence. The aim of this study was to investigate the properties of the microenvironments associated with these regions. For this purpose, we isolated glioma-associated stem cells (GASC), resident in the glioma microenvironment, from ALA+, ALA-PALE and ALA- samples and compared them in terms of growth kinetic, phenotype and for the expression of 84 genes associated with cancer inflammation and immunity. Differentially expressed genes were correlated with transcriptomic datasets from TCGA/GTEX. Our results show that GASC derived from the three distinct regions, despite a similar phenotype, were characterized by different transcriptomic profiles. Moreover, we identified a GASC-based genetic signature predictive of overall survival and disease-free survival. This signature, highly expressed in ALA+ GASC, was also well represented in ALA PALE GASC. 5-ALA FGS allowed to underline the heterogeneity of the glioma microenvironments. Deepening knowledge of these differences can contribute to develop new adjuvant therapies targeting the crosstalk between tumor and its supporting microenvironment.
    Keywords:  5-aminolevulinc acid; fluorescence guided surgery; glioblastoma microenvironment; glioma associated stem cells; tumor supporting signature
    DOI:  https://doi.org/10.3390/cancers12102960
  6. Cancers (Basel). 2020 Oct 08. pii: E2888. [Epub ahead of print]12(10):
    Dinevska M, Gazibegovic N, Morokoff AP, Kaye AH, Drummond KJ, Mantamadiotis T, Stylli SS.
      Glioblastoma (GBM) is the most prevalent and malignant type of primary brain cancer. The rapid invasion and dissemination of tumor cells into the surrounding normal brain is a major driver of tumor recurrence, and long-term survival of GBM patients is extremely rare. Actin-rich cell membrane protrusions known as invadopodia can facilitate the highly invasive properties of GBM cells. Ion channels have been proposed to contribute to a pro-invasive phenotype in cancer cells and may also be involved in the invadopodia activity of GBM cells. GBM cell cytotoxicity screening of several ion channel drugs identified three drugs with potent cell killing efficacy: flunarizine dihydrochloride, econazole nitrate, and quinine hydrochloride dihydrate. These drugs demonstrated a reduction in GBM cell invadopodia activity and matrix metalloproteinase-2 (MMP-2) secretion. Importantly, the treatment of GBM cells with these drugs led to a significant reduction in radiation/temozolomide-induced invadopodia activity. The dual cytotoxic and anti-invasive efficacy of these agents merits further research into targeting ion channels to reduce GBM malignancy, with a potential for future clinical translation in combination with the standard therapy.
    Keywords:  drug repurposing; glioblastoma; glioma; invadopodia; invasion; ion channels
    DOI:  https://doi.org/10.3390/cancers12102888
  7. Cancers (Basel). 2020 Oct 10. pii: E2910. [Epub ahead of print]12(10):
    Dowdy T, Zhang L, Celiku O, Movva S, Lita A, Ruiz-Rodado V, Gilbert MR, Larion M.
      In addition to providing integrity to cellular structure, the various classes of lipids participate in a multitude of functions including secondary messengers, receptor stimulation, lymphocyte trafficking, inflammation, angiogenesis, cell migration, proliferation, necrosis and apoptosis, thus highlighting the importance of understanding their role in the tumor phenotype. In the context of IDH1mut glioma, investigations focused on metabolic alterations involving lipidomics' present potential to uncover novel vulnerabilities. Herein, a detailed lipidomic analysis of the sphingolipid metabolism was conducted in patient-derived IDH1mut glioma cell lines, as well as model systems, with the of identifying points of metabolic vulnerability. We probed the effect of decreasing D-2HG levels on the sphingolipid pathway, by treating these cell lines with an IDH1mut inhibitor, AGI5198. The results revealed that N,N-dimethylsphingosine (NDMS), sphingosine C17 and sphinganine C18 were significantly downregulated, while sphingosine-1-phosphate (S1P) was significantly upregulated in glioma cultures following suppression of IDH1mut activity. We exploited the pathway using a small-scale, rational drug screen and identified a combination that was lethal to IDHmut cells. Our work revealed that further addition of N,N-dimethylsphingosine in combination with sphingosine C17 triggered a dose-dependent biostatic and apoptotic response in a panel of IDH1mut glioma cell lines specifically, while it had little effect on the IDHWT cells probed here. To our knowledge, this is the first study that shows how altering the sphingolipid pathway in IDH1mut gliomas elucidates susceptibility that can arrest proliferation and initiate subsequent cellular death.
    Keywords:  IDHmut gliomas; N,N-dimethylsphingosine; sphinganine; sphingolipid metabolism; sphingosine
    DOI:  https://doi.org/10.3390/cancers12102910
  8. J Pathol. 2020 Oct 12.
    Blank A, Kremenetskaia I, Urbantat RM, Acker G, Turkowski K, Radke J, Schneider UC, Vajkoczy P, Brandenburg S.
      Myeloid cells are an inherent part of the microenvironment of glioblastoma multiforme (GBM). There is growing evidence for their participation in mechanisms of tumor escape, especially in development of resistance following initially promising anti-VEGF/VEGFR treatment. Thus, we sought to define the capability of myeloid cells to contribute to the expression of proangiogenic molecules in human GBM. We investigated GBM specimens in comparison to anaplastic astrocytoma (WHO grade III) and epilepsy patient samples freshly obtained from surgery. Flow cytometric analyses revealed two distinct CD11b+ CD45+ cell populations in GBM tissues, which were identified as microglia/macrophages and granulocytes. Due to varied granulocyte influx, GBM samples were subdivided into groups with low (GBM-lPMNL) and high numbers of granulocytes (GBM-hPMNL), which were related to activation of the microglia/macrophage population. Microglia/macrophages of the GBM-lPMNL group were similar to those of astrocytoma specimens, but those of GBM-hPMNL tissues revealed an altered phenotype by expressing high levels of CD163, TIE2, HIF1α, VEGF, CXCL2 and CD13. While microglia/macrophages represented the main source of alternative proangiogenic factors, additionally granulocytes participated by production of IL8 and CD13. Moreover, microglia/macrophages of the GBM-hPMNL specimens were highly associated with tumor blood vessels, accompanied by remodeling of the vascular structure. Our data emphasize that tumor-infiltrating myeloid cells might play a crucial role for limited efficacy of anti-angiogenic therapy bypassing VEGF mediated pathways through expression of alternative proangiogenic factors. This article is protected by copyright. All rights reserved.
    Keywords:  CD45; CSF; CXCL2; GBM; granulocytes; macrophages; microglia; tumor angiogenesis; tumor microenvironment
    DOI:  https://doi.org/10.1002/path.5569
  9. Cancers (Basel). 2020 Oct 12. pii: E2937. [Epub ahead of print]12(10):
    Whitehouse JP, Howlett M, Hii H, Mayoh C, Wong M, Barahona P, Ajuyah P, White CL, Buntine MK, Dyke JM, Lee S, Valvi S, Stanley J, Andradas C, Carline B, Kuchibhotla M, Ekert PG, Cowley MJ, Gottardo NG, Endersby R.
      Radiation-induced glioma (RIG) is a highly aggressive brain cancer arising as a consequence of radiation therapy. We report a case of RIG that arose in the brain stem following treatment for paediatric medulloblastoma, and the development and characterisation of a matched orthotopic patient-derived xenograft (PDX) model (TK-RIG915). Patient and PDX tumours were analysed using DNA methylation profiling, whole genome sequencing (WGS) and RNA sequencing. While initially thought to be a diffuse intrinsic pontine glioma (DIPG) based on disease location, results from methylation profiling and WGS were not consistent with this diagnosis. Furthermore, clustering analyses based on RNA expression suggested the tumours were distinct from primary DIPG. Additional gene expression analysis demonstrated concordance with a published RIG expression profile. Multiple genetic alterations that enhance PI3K/AKT and Ras/Raf/MEK/ERK signalling were discovered in TK-RIG915 including an activating mutation in PIK3CA, upregulation of PDGFRA and AKT2, inactivating mutations in NF1, and a gain-of-function mutation in PTPN11. Additionally, deletion of CDKN2A/B, increased IDH1 expression, and decreased ARID1A expression were observed. Detection of phosphorylated S6, 4EBP1 and ERK via immunohistochemistry confirmed PI3K pathway and ERK activation. Here, we report one of the first PDX models for RIG, which recapitulates the patient disease and is molecularly distinct from primary brain stem glioma. Genetic interrogation of this model has enabled the identification of potential therapeutic vulnerabilities in this currently incurable disease.
    Keywords:  brain cancer; diffuse intrinsic pontine glioma; diffuse midline glioma; medulloblastoma; paediatric cancer; patient-derived xenograft; radiation; radiation-induced glioma
    DOI:  https://doi.org/10.3390/cancers12102937
  10. Front Oncol. 2020 ;10 1631
    He Z, Wang C, Xue H, Zhao R, Li G.
      Altered metabolism of glucose, lipid and glutamine is a prominent hallmark of cancer cells. Currently, cell heterogeneity is believed to be the main cause of poor prognosis of glioblastoma (GBM) and is closely related to relapse caused by therapy resistance. However, the comprehensive model of genes related to glucose-, lipid- and glutamine-metabolism associated with the prognosis of GBM remains unclear, and the metabolic heterogeneity of GBM still needs to be further explored. Based on the expression profiles of 1,395 metabolism-related genes in three datasets of TCGA/CGGA/GSE, consistent cluster analysis revealed that GBM had three different metabolic status and prognostic clusters. Combining univariate Cox regression analysis and LASSO-penalized Cox regression machine learning methods, we identified a 17-metabolism-related genes risk signature associated with GBM prognosis. Kaplan-Meier analysis found that obtained signature could differentiate the prognosis of high- and low-risk patients in three datasets. Moreover, the multivariate Cox regression analysis and receiver operating characteristic curves indicated that the signature was an independent prognostic factor for GBM and had a strong predictive power. The above results were further validated in the CGGA and GSE13041 datasets, and consistent results were obtained. Gene set enrichment analysis (GSEA) suggested glycolysis gluconeogenesis and oxidative phosphorylation were significantly enriched in high- and low-risk GBM. Lastly Connectivity Map screened 54 potential compounds specific to different subgroups of GBM patients. Our study identified a novel metabolism-related gene signature, in addition the existence of three different metabolic status and two opposite biological processes in GBM were recognized, which revealed the metabolic heterogeneity of GBM. Robust metabolic subtypes and powerful risk prognostic models contributed a new perspective to the metabolic exploration of GBM.
    Keywords:  glioblastoma; heterogeneity; metabolism; prognosis; signature
    DOI:  https://doi.org/10.3389/fonc.2020.01631
  11. Clin Cancer Res. 2020 Oct 15. pii: clincanres.0894.2020. [Epub ahead of print]
    Montay-Gruel P, Acharya MM, Gonçalves Jorge P, Petit B, Petridis IG, Fuchs P, Leavitt R, Petersson K, Gondre M, Ollivier J, Moeckli R, Bochud F, Bailat C, Bourhis J, Germond JF, Limoli CL, Vozenin MC.
      PURPOSE: Recent data has shown that single fraction irradiation delivered to the whole brain in less than tenths of a second using FLASH radiation therapy (RT), does not elicit neurocognitive deficits in mice. This observation has important clinical implications for the management of invasive and treatment-resistant brain tumors that involves relatively large irradiation volumes with high cytotoxic doses.EXPERIMENTAL DESIGN: Therefore, we aimed at simultaneously investigating the anti-tumor efficacy and neuroprotective benefits of FLASH-RT 1-month after exposure, using a well-characterized murine orthotopic glioblastoma model. As fractionated regimens of radiotherapy are the standard of care for glioblastoma treatment, we incorporated dose fractionation to simultaneously validate the neuroprotective effects and optimized tumor treatments with FLASH-RT.
    RESULTS: The capability of FLASH-RT to minimize the induction of radiation-induced brain toxicities has been attributed to the reduction of reactive oxygen species, casting some concern that this might translate to a possible loss of anti-tumor efficacy. Our study shows that FLASH and CONV-RT are iso-efficient in delaying GBM growth for all tested regimens. Furthermore, only FLASH-RT was found to significantly spare radiation-induced cognitive deficits in learning and memory in tumor bearing animals after the delivery of large neurotoxic single dose or hypo-fractionated regimens.
    CONCLUSION: The present results show that FLASH-RT delivered with hypo-fractionated regimens is able to spare the normal brain from radiation-induced toxicities without compromising tumor cure. This exciting capability provides an initial framework for future clinical applications of FLASH-RT.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-20-0894
  12. Cancers (Basel). 2020 Oct 09. pii: E2889. [Epub ahead of print]12(10):
    Amero P, Khatua S, Rodriguez-Aguayo C, Lopez-Berestein G.
      A relatively new paradigm in cancer therapeutics is the use of cancer cell-specific aptamers, both as therapeutic agents and for targeted delivery of anticancer drugs. After the first therapeutic aptamer was described nearly 25 years ago, and the subsequent first aptamer drug approved, many efforts have been made to translate preclinical research into clinical oncology settings. Studies of aptamer-based technology have unveiled the vast potential of aptamers in therapeutic and diagnostic applications. Among pediatric solid cancers, brain tumors are the leading cause of death. Although a few aptamer-related translational studies have been performed in adult glioblastoma, the use of aptamers in pediatric neuro-oncology remains unexplored. This review will discuss the biology of aptamers, including mechanisms of targeting cell surface proteins, various modifications of aptamer structure to enhance therapeutic efficacy, the current state and challenges of aptamer use in neuro-oncology, and the potential therapeutic role of aptamers in pediatric brain tumors.
    Keywords:  aptamers; blood–brain barrier; diagnostic; neuro-oncology; pediatric; therapeutic
    DOI:  https://doi.org/10.3390/cancers12102889
  13. Front Bioeng Biotechnol. 2020 ;8 538663
    Sivakumar H, Devarasetty M, Kram DE, Strowd RE, Skardal A.
      Glioblastoma (GBM) is a lethal, incurable form of cancer in the brain. Even with maximally aggressive surgery and chemoradiotherapy, median patient survival is 14.5 months. These tumors infiltrate normal brain tissue, are surgically incurable, and universally recur. GBMs are characterized by genetic, epigenetic, and microenvironmental heterogeneity, and they evolve spontaneously over time and as a result of treatment. However, tracking such heterogeneity in real time in response to drug treatments has been impossible. Here we describe the development of an in vitro GBM tumor organoid model that is comprised of five distinct cellular subpopulations (4 GBM cell lines that represent GBM subpopulations and 1 astrocyte line), each fluorescently labeled with a different color. These multi-cell type GBM organoids are then embedded in a brain-like hyaluronic acid hydrogel for subsequent studies involving drug treatments and tracking of changes in relative numbers of each fluorescently unique subpopulation. This approach allows for the visual assessment of drug influence on individual subpopulations within GBM, and in future work can be expanded to supporting studies using patient tumor biospecimen-derived cells for personalized diagnostics.
    Keywords:  drug response; glioblastoma; organoid; spheroid; tumor heterogeneity
    DOI:  https://doi.org/10.3389/fbioe.2020.538663