bims-malgli Biomed News
on Biology of malignant gliomas
Issue of 2021‒05‒23
seventeen papers selected by
Oltea Sampetrean
Keio University

  1. Oncotarget. 2021 May 11. 12(10): 967-981
      CD4+ helper T (Th) cells play a critical role in shaping anti-tumor immunity by virtue of their ability to differentiate into multiple lineages in response to environmental cues. Various CD4+ lineages can orchestrate a broad range of effector activities during the initiation, expansion, and memory phase of endogenous anti-tumor immune response. In this clinical corelative study, we found that Glioblastoma (GBM) induces multi- and mixed-lineage immune response in the tumor microenvironment. Whole-genome bisulfite sequencing of tumor infiltrating and blood CD4+ T-cell from GBM patients showed 13571 differentially methylated regions and a distinct methylation pattern of methylation of tumor infiltrating CD4+ T-cells with significant inter-patient variability. The methylation changes also resulted in transcriptomic changes with 341 differentially expressed genes in CD4+ tumor infiltrating T-cells compared to blood. Analysis of specific genes involved in CD4+ differentiation and function revealed differential methylation status of TBX21, GATA3, RORC, FOXP3, IL10 and IFNG in tumor CD4+ T-cells. Analysis of lineage specific genes revealed differential methylation and gene expression in tumor CD4+ T-cells. Interestingly, we observed dysregulation of several ligands of T cell function genes in GBM tissue corresponding to the T-cell receptors that were dysregulated in tumor infiltrating CD4+ T-cells. Our results suggest that GBM might induce epigenetic alterations in tumor infiltrating CD4+ T-cells there by influencing anti-tumor immune response by manipulating differentiation and function of tumor infiltrating CD4+ T-cells. Thus, further research is warranted to understand the role of tumor induced epigenetic modification of tumor infiltrating T-cells to develop effective anti-GBM immunotherapy.
    Keywords:  CD4+ T cell; DNA methylation; brain cancer; glioblastoma; malignant glioma
  2. Oncogene. 2021 May 21.
      Intratumoral heterogeneity is a characteristic of glioblastomas that contain an intermixture of cell populations displaying different glioblastoma subtype gene expression signatures. Proportions of these populations change during tumor evolution, but the occurrence and regulation of glioblastoma subtype transition is not well described. To identify regulators of glioblastoma subtypes we utilized a combination of in vitro experiments and in silico analyses, using experimentally generated as well as publicly available data. Through this combined approach SOX2 was identified to confer a proneural glioblastoma subtype gene expression signature. SFRP2 was subsequently identified as a SOX2-antagonist, able to induce a mesenchymal glioblastoma subtype signature. A subset of patient glioblastoma samples with high SFRP2 and low SOX2 expression was particularly enriched with mesenchymal subtype samples. Phenotypically, SFRP2 decreased tumor sphere formation, stemness as assessed by limiting dilution assay, and overall cell proliferation but increased cell motility, whereas SOX2 induced the opposite effects. Furthermore, an SFRP2/non-canonical-WNT/KLF4/PDGFR/phospho-AKT/SOX2 signaling axis was found to be involved in the mesenchymal transition. Analysis of human tumor tissue spatial gene expression patterns showed distinct expression of SFRP2- and SOX2-correlated genes in vascular and cellular areas, respectively. Finally, conditioned media from SFRP2 overexpressing cells increased CD206 on macrophages. Together, these findings present SFRP2 as a SOX2-antagonist with the capacity to induce a mesenchymal subtype transition in glioma cells located in vascular tumor areas, highlighting its role in glioblastoma tumor evolution and intratumoral heterogeneity.
  3. Int J Oncol. 2021 Jul;pii: 45. [Epub ahead of print]59(1):
      Glioblastoma multiforme (GBM) is a primary brain tumor with a high mortality rate and a median survival time of ~14 months from the initial diagnosis. Although progress has been made in the currently available therapies, the treatment of GBM remains palliative. GBM contains subsets of GBM stem cells (GSCs) that share numerous neural stem/progenitor cell characteristics, such as expression of stem cell markers, self‑renewal and multi‑lineage differentiation capacity, thus contributing to the heterogeneity and complexity of these tumors. GSCs are potentially associated with tumor initiation and they are considered as the driving force behind tumor formation, as they possess tumor‑propagating potential and exhibit preferential resistance to radiotherapy and chemotherapy. Targeting self‑renewal signaling pathways in cancer stem cells may effectively reduce tumor recurrence and significantly improve prognosis. The aim of the present review was to summarize the current knowledge on the self‑renewal signaling pathways of GSCs and discuss potential future targeting strategies for the design of differentiation therapies.
    Keywords:  differentiation therapies; glioblastoma; glioblastoma stem cells; self‑renewal signaling pathways
  4. J Drug Target. 2021 May 20. 1-6
      Vascular normalisation refers to a 'remodeling' of the dysfunctional tumour capillary network, which regresses under the influence of anti-VEGF treatment, resulting in improved blood flow and oxygenation. RRx-001 is an anti-CD47-SIRPα small molecule with vascular normalising properties under investigation in clinical trials for the treatment of glioblastoma, brain metastases, lung cancer and colorectal cancer, with FDA Orphan Drug Designation in glioblastoma and other tumour types. This study investigated whether the improved oxygenation and perfusion that has been previously observed with RRx-001 both preclinically and clinically in the context of a brain metastasis trial was correlated with increased penetration and accumulation of the cytotoxic chemotherapies, irinotecan and temozolomide, in orthotopically implanted gliomas, priming tumours for improved response. The experiments demonstrate that administration of RRx-001 prior to temozolomide or irinotecan results in significantly increased uptake of irinotecan and temozolomide in orthotopic glioma tumours. Since the success of chemotherapy in the brain (and outside of it) is limited by subtherapeutic tumoral drug concentrations, vascular normalisation-enhanced delivery of standard cytotoxics as demonstrated with RRx-001 may mitigate or reverse clinical drug resistance and thereby improve the outcome of cancer therapy, particularly in the brain.
    Keywords:  BBB; CD-47 downregulation; Chemotherapy; RRx-001; irinotecan; temozolomide; tumor associated macrophage polarisation; vascular normalisation; vascular priming
  5. Nanoscale. 2021 May 21.
      Brain fatty acid binding protein (FABP7; B-FABP) promotes glioblastoma (GBM) cell migration and is associated with tumor infiltration, properties associated with a poor prognosis in GBM patients. FABP7-expressing neural stem-like cells are known to drive tumor migration/infiltration and resistance to treatment. We have previously shown that FABP7's effects on cell migration can be reversed when GBM cells are cultured in medium supplemented with the omega-3 fatty acid, docosahexaenoic acid (DHA). Here, we use super-resolution imaging on patient-derived GBM stem-like cells to examine the importance of FABP7 and its fatty acid ligands in mitigating GBM cell migration. As FABPs are involved in fatty acid transport from membrane to cytosol, we focus on the effect of FABP7 and its ligand DHA on GBM membrane remodeling, as well as FABP7 nanoscale domain formation on GBM membrane. Using quantitative plasma membrane lipid order imaging, we show that FABP7 expression in GBM cells correlates with increased membrane lipid order, with DHA dramatically decreasing lipid order. Using super-resolution stimulated emission depletion (STED) microscopy, we observe non-uniform distribution of FABP7 on the surface of GBM cells, with FABP7 forming punctate nanoscale domains of ∼100 nm in diameter. These nanodomains are particularly enriched at the migrating front of GBM cells. Interestingly, FABP7 nanodomains are disrupted when GBM cells are cultured in DHA-supplemented medium. We demonstrate a tight link between cell migration, a higher membrane lipid order and increased FABP7 nanoscale domains. We propose that DHA-mediated disruption of membrane lipid order and FABP7 nanodomains forms the basis of FABP7/DHA-mediated inhibition of cell migration in GBM.
  6. Neurooncol Adv. 2021 Jan-Dec;3(1):3(1): vdab038
      Background: Thalamic high-grade gliomas (HGGs) are rare tumors with a dismal prognosis. H3K27M and telomerase reverse transcriptase promoter (TERTp) mutations reportedly contribute to poor prognoses in HGG cases. We investigated the outcomes of surgically treated adult thalamic HGGs to evaluate the prognostic significance of H3K27M and TERTp mutations.Methods: We retrospectively analyzed 25 adult patients with thalamic HGG who underwent maximum surgical resection from January 1997 to March 2020. The histological and molecular characteristics, progression-free survival (PFS), and overall survival (OS) of the patients were compared. For molecular characteristics, target sequencing was used to determine the H3F3A, HIST1H3B, and TERTp mutations.
    Results: H3K27M mutations were detected in 12/25 (48.0%) patients. TERTp mutations were not detected in H3K27M-mutant gliomas but were detected in 8/13 (61.5%) of H3 wild-type gliomas. Although it was not significant, H3K27M-mutant gliomas tended to have a shorter PFS (6.7 vs 13.1 months; P = .2928) and OS (22.8 vs 24.4 months; P = .2875) than H3 wild-type gliomas. Moreover, the prognosis of TERTp-mutant gliomas was as poor as that of H3K27M-mutant gliomas. Contrary, 5 gliomas harboring both H3 and TERTp wild-type showed a better median PFS (59.2 vs 6.4 months; P = .0456) and OS (71.8 vs 24.4 months; P = .1168) than those harboring H3K27M or TERTp mutations.
    Conclusions: TERTp-mutant gliomas included in the H3 wild-type glioma group limited patient survival as they exhibited an aggressive course similar to H3K27M-mutant gliomas. Comprehensive molecular work-up for the H3 wild-type cases may further confirm this finding.
    Keywords:  H3K27M; TERT promoter mutation; adult thalamic glioma; high-grade glioma; surgical resection
  7. Oncogene. 2021 May 20.
      Glioma is the most common and fatal primary malignant brain tumor. Glioma stem cells (GSCs) may be an important factor in glioma cell proliferation, invasion, chemoradiotherapy tolerance, and recurrence. Therefore, discovering novel GSCs related circular RNAs (circRNAs) may finds out a prospective target for the treatment of glioma. A novel circRNA-CHAF1A (circCHAF1A) was first found in our study. CircCHAF1A was overexpressed in glioma and related to the low survival rate. Functionally, it was found that no matter in vitro or in vivo, circCHAF1A can facilitate the proliferation and tumorigenesis of TP53wt GSCs. Mechanistically, circCHAF1A upregulated transcription factor HOXC8 expression in GSCs through miR-211-5p sponging. Then, HOXC8 can transcriptionally upregulate MDM2 expression and inhibited the antitumor effect of p53. Furtherly, the RNA binding protein FMR1 can bind to and promoted the expression of circCHAF1A via maintaining its stability, while HOXC8 also transcribed the FMR1 expression to form a feedback loop, which may be involved in the malignant transformation of glioma. The novel feedback loop among FMR1, circCHAF1A, miR-211-5p, and HOXC8 in GSCs can facilitate the proliferation and tumorigenesis of glioma and GSCs. It also provided a helpful biomarker for diagnosis and prognostic evaluation of glioma and may be applied to molecular targeted therapy.
  8. Biomater Sci. 2021 May 21.
      Glioblastoma multiforme (GBM) is the most aggressive form of gliomas. The development of supplementary approaches for glioblastoma diagnosis, limited to imaging techniques and tissue biopsies so far, is a necessity of clinical relevance. In this context, nanotechnology might afford tools to enable early diagnosis. Upon exposure to biological media, nanoparticles are coated with a layer of proteins, the protein corona (PC), whose composition is individual and personalized. Here we show that the PC of graphene oxide nanosheets has a capacity to detect GBM using a simple one-dimensional gel electrophoresis technique. In a range of molecular weights between 100 and 120 kDa, the personalized PC from GBM patients is completely discernible from that of healthy donors and that of cancer patients affected by pancreatic adenocarcinoma and colorectal cancer. Using tandem mass spectrometry, we found that inter-alpha-trypsin inhibitor (ITI) heavy chain H4 is enriched in the PC of all tested individuals but not in the GBM patients. Overall, if confirmed on a larger cohort series, this approach could be advantageous at the first level of investigation to decide whether to carry out more invasive analyses and/or to follow up patients after surgery and/or pharmacological treatment.
  9. Biol Open. 2020 Jan 01. pii: bio.053405. [Epub ahead of print]
      Glioblastoma (GB) is the most aggressive and lethal tumour of the central nervous system (CNS). GB cells grow rapidly and display a network of projections (ultra-long tumour microtubes (TMs)), that mediate cell to cell communication. GB-TMs infiltrate throughout the brain, enwrap neurons and facilitate the depletion of the signalling molecule wingless (Wg)/WNT from the neighbouring healthy neurons. GB cells establish a positive feedback loop including Wg signalling upregulation that activates cJun N-terminal kinase (JNK) pathway and matrix metalloproteases (MMPs) production, which in turn promote further TMs infiltration, GB progression and neurodegeneration. Thus, cellular and molecular signals other than primary mutations emerge as central players of GB. Using a Drosophila model of GB, we describe the temporal organization of the main cellular events that occur in GB, including cell to cell interactions, neurodegeneration and TMs expansion. We define the progressive activation of JNK pathway signalling in GB mediated by the receptor Grindelwald (Grnd) and activated by the ligand Eiger (Egr)/TNFα produced by surrounding healthy brain tissue. We propose that cellular interactions of GB with the healthy brain tissue precede TM expansion and conclude that non-autonomous signals facilitate GB progression. These results contribute to deciphering the complexity and versatility of these incurable tumours.
    Keywords:  Cancer; Glia; Glioblastoma; JNK; Neurodegeneration; Tumour Microtubes
  10. Genome Med. 2021 May 19. 13(1): 88
      BACKGROUND: Macrophages are the most common infiltrating immune cells in gliomas and play a wide variety of pro-tumor and anti-tumor roles. However, the different subpopulations of macrophages and their effects on the tumor microenvironment remain poorly understood.METHODS: We combined new and previously published single-cell RNA-seq data from 98,015 single cells from a total of 66 gliomas to profile 19,331 individual macrophages.
    RESULTS: Unsupervised clustering revealed a pro-tumor subpopulation of bone marrow-derived macrophages characterized by the scavenger receptor MARCO, which is almost exclusively found in IDH1-wild-type glioblastomas. Previous studies have implicated MARCO as an unfavorable marker in melanoma and non-small cell lung cancer; here, we find that bulk MARCO expression is associated with worse prognosis and mesenchymal subtype. Furthermore, MARCO expression is significantly altered over the course of treatment with anti-PD1 checkpoint inhibitors in a response-dependent manner, which we validate with immunofluorescence imaging.
    CONCLUSIONS: These findings illustrate a novel macrophage subpopulation that drives tumor progression in glioblastomas and suggest potential therapeutic targets to prevent their recruitment.
    Keywords:  Cancer immunotherapy; Glioblastoma; Macrophages; Single-cell RNA-seq
  11. Cell Death Differ. 2021 May 18.
      The basic function of β-arrestin 2 (Arrb2) is to negatively regulate the G-protein-coupled receptor signaling pathway through facilitating receptor desensitization and internalization. Arrb2 has also been reported to play various roles in cancer pathology including the proliferation, migration, invasion, metastasis, and apoptosis of solid tumors. However, the molecular mechanisms underlying the tumorigenic capacities of Arrb2 have not been elucidated. Here, we show a novel function of Arrb2: Arrb2 facilitates the degradation of HIF-1α, which is a master regulator of oxygen homeostasis. We also demonstrate that Arrb2 interacts with HIF-1α and stimulates ubiquitin-mediated 26S proteasomal degradation of HIF-1α by recruiting PHD2 and pVHL. Overexpression of Arrb2 in human glioblastoma cells suppresses HIF-1α signaling, tumor growth, and angiogenesis. Consistent with this antitumorigenic effect of Arrb2, low Arrb2 expression levels correlate with high HIF-1α expression and poor glioblastoma patient survival. These results collectively reveal a novel function of Arrb2 in the oxygen-sensing mechanism that directly regulates HIF-1α stability in human cancers and suggest Arrb2 as a new potential therapeutic target for glioblastoma.
  12. Cancer Metab. 2021 May 19. 9(1): 24
      BACKGROUND: Neuroblastoma accounts for 7% of paediatric malignancies but is responsible for 15% of all childhood cancer deaths. Despite rigorous treatment involving chemotherapy, surgery, radiotherapy and immunotherapy, the 5-year overall survival rate of high-risk disease remains < 40%, highlighting the need for improved therapy. Since neuroblastoma cells exhibit aberrant metabolism, we determined whether their sensitivity to radiotherapy could be enhanced by drugs affecting cancer cell metabolism.METHODS: Using a panel of neuroblastoma and glioma cells, we determined the radiosensitising effects of inhibitors of glycolysis (2-DG) and mitochondrial function (metformin). Mechanisms underlying radiosensitisation were determined by metabolomic and bioenergetic profiling, flow cytometry and live cell imaging and by evaluating different treatment schedules.
    RESULTS: The radiosensitising effects of 2-DG were greatly enhanced by combination with the antidiabetic biguanide, metformin. Metabolomic analysis and cellular bioenergetic profiling revealed this combination to elicit severe disruption of key glycolytic and mitochondrial metabolites, causing significant reductions in ATP generation and enhancing radiosensitivity. Combination treatment induced G2/M arrest that persisted for at least 24 h post-irradiation, promoting apoptotic cell death in a large proportion of cells.
    CONCLUSION: Our findings demonstrate that the radiosensitising effect of 2-DG was significantly enhanced by its combination with metformin. This clearly demonstrates that dual metabolic targeting has potential to improve clinical outcomes in children with high-risk neuroblastoma by overcoming radioresistance.
    Keywords:  131I-MIBG; 2-DG; Metabolism; Metformin; Neuroblastoma; Radiation
  13. Acta Neuropathol Commun. 2021 May 17. 9(1): 88
      Diffuse intrinsic pontine glioma (DIPG), a rare pediatric brain tumor, afflicts approximately 350 new patients each year in the United States. DIPG is noted for its lethality, as fewer than 1% of patients survive to five years. Multiple clinical trials involving chemotherapy, radiotherapy, and/or targeted therapy have all failed to improve clinical outcomes. Recently, high-throughput sequencing of a cohort of DIPG samples identified potential therapeutic targets, including interleukin 13 receptor subunit alpha 2 (IL13Rα2) which was expressed in multiple tumor samples and comparably absent in normal brain tissue, identifying IL13Rα2 as a potential therapeutic target in DIPG. In this work, we investigated the role of IL13Rα2 signaling in progression and invasion of DIPG and viability of IL13Rα2 as a therapeutic target through the use of immunoconjugate agents. We discovered that IL13Rα2 stimulation via canonical ligands demonstrates minimal impact on both the cellular proliferation and cellular invasion of DIPG cells, suggesting IL13Rα2 signaling is non-essential for DIPG progression in vitro. However, exposure to an anti-IL13Rα2 antibody-drug conjugate demonstrated potent pharmacological response in DIPG cell models both in vitro and ex ovo in a manner strongly associated with IL13Rα2 expression, supporting the potential use of targeting IL13Rα2 as a DIPG therapy. However, the tested ADC was effective in most but not all cell models, thus selection of the optimal payload will be essential for clinical translation of an anti-IL13Rα2 ADC for DIPG.
    Keywords:  Antibody–drug conjugates; Diffuse intrinsic pontine glioma; IL13Rα2; Immunotherapy; Pediatric cancer
  14. Cancer Res. 2021 May 18. pii: canres.0035.2021. [Epub ahead of print]
      Interleukin (IL)-15 is a pleiotropic cytokine with multiple roles that improve immune responses to tumor cells. Oncolytic viruses (OV) specifically lyse tumors and activate immune responses. Systemic administration of IL-15 or its complex with the IL-15Rα and chimeric antigen receptor (CAR) natural killer (NK) cells are currently being tested in the clinic. Here we generated a herpes simplex 1-based OV expressing human IL-15/IL-15Rα sushi domain fusion protein (named OV-IL15C), as well as off-the-shelf EGFR-CAR NK cells, and studied their monotherapy and combination efficacy in vitro and in multiple glioblastoma (GBM) mouse models. In vitro, soluble IL-15/IL-15Rα complex was secreted from OV-IL15C-infected GBM cells, which promoted GBM cytotoxicity and improved survival of NK and CD8+ T cells. Frozen, readily available off-the-shelf EGFR-CAR NK cells showed enhanced killing of tumor cells compared to empty vector-transduced NK cells. In vivo, OV-IL15C significantly inhibited tumor growth and prolonged survival of GBM-bearing mice in the presence of CD8+ T cells compared to parental OV. OV-IL15C plus EGFR-CAR NK cells synergistically suppressed tumor growth and significantly improved survival compared to either monotherapy, correlating with increased intracranial infiltration and activation of NK and CD8+ T cells and elevated persistence of CAR NK cells in an immunocompetent model. Collectively, OV-IL15C and off-the-shelf EGFR-CAR NK cells represent promising therapeutic strategies for GBM treatment to improve the clinical management of this devastating disease.
  15. Nanomedicine (Lond). 2021 May 17.
    Keywords:  blood–brain barrier; convection-enhanced delivery; diffuse midline glioma; nanoparticle
  16. Neurooncol Adv. 2021 Jan-Dec;3(1):3(1): vdab039
      Background: Diffuse intrinsic pontine glioma (DIPG) is a devastating pediatric cancer with unmet clinical need. DIPG is invasive in nature, where tumor cells interweave into the fiber nerve tracts of the pons making the tumor unresectable. Accordingly, novel approaches in combating the disease are of utmost importance and receptor-driven cell invasion in the context of DIPG is under-researched area. Here, we investigated the impact on cell invasion mediated by PLEXINB1, PLEXINB2, platelet growth factor receptor (PDGFR)α, PDGFRβ, epithelial growth factor receptor (EGFR), activin receptor 1 (ACVR1), chemokine receptor 4 (CXCR4), and NOTCH1.Methods: We used previously published RNA-sequencing data to measure gene expression of selected receptors in DIPG tumor tissue versus matched normal tissue controls (n = 18). We assessed protein expression of the corresponding genes using DIPG cell culture models. Then, we performed cell viability and cell invasion assays of DIPG cells stimulated with chemoattractants/ligands.
    Results: RNA-sequencing data showed increased gene expression of receptor genes such as PLEXINB2, PDGFRα, EGFR, ACVR1, CXCR4, and NOTCH1 in DIPG tumors compared to the control tissues. Representative DIPG cell lines demonstrated correspondingly increased protein expression levels of these genes. Cell viability assays showed minimal effects of growth factors/chemokines on tumor cell growth in most instances. Recombinant SEMA4C, SEM4D, PDGF-AA, PDGF-BB, ACVA, CXCL12, and DLL4 ligand stimulation altered invasion in DIPG cells.
    Conclusions: We show that no single growth factor-ligand pair universally induces DIPG cell invasion. However, our results reveal a potential to create a composite of cytokines or anti-cytokines to modulate DIPG cell invasion.
    Keywords:  DIPG; cell invasion; chemokine/cytokine; receptor