bims-malgli Biomed News
on Biology of malignant gliomas
Issue of 2022‒02‒27
twenty papers selected by
Oltea Sampetrean
Keio University

  1. Biomedicines. 2022 Feb 11. pii: 427. [Epub ahead of print]10(2):
      Glioblastoma remains a challenging disease to treat, despite well-established standard-of-care treatments, with a median survival consistently of less than 2 years. In this review, we delineate the unique disease-specific challenges for immunotherapies, both brain-related and non-brain-related, which will need to be adequately overcome for the development of effective treatments. We also review current immunotherapy treatments, with a focus on clinical applications, and propose future directions for the field of GBM immunotherapy.
    Keywords:  GBM; biologic therapy; chemotherapy; glioblastoma; glioma; radiotherapy; surgery
  2. EMBO J. 2022 Feb 22. e109187
      Hypoxia regulates tumor angiogenesis, metabolism, and therapeutic response in malignant cancers including glioblastoma, the most lethal primary brain tumor. The regulation of HIF transcriptional factors by the ubiquitin-proteasome system is critical in the hypoxia response, but hypoxia-inducible deubiquitinases that counteract the ubiquitination remain poorly defined. While the activation of ERK1/2 also plays an important role in hypoxia response, the relationship between ERK1/2 activation and HIF regulation remains elusive. Here, we identified USP33 as essential deubiquitinase that stabilizes HIF-2alpha protein in an ERK1/2-dependent manner to promote hypoxia response in cancer cells. USP33 is preferentially induced in glioma stem cells by hypoxia and interacts with HIF-2alpha, leading to its stabilization through deubiquitination. The activation of ERK1/2 upon hypoxia promoted HIF-2alpha phosphorylation, enhancing its interaction with USP33. Silencing of USP33 disrupted glioma stem cells maintenance, reduced tumor vascularization, and inhibited glioblastoma growth. Our findings highlight USP33 as an essential regulator of hypoxia response in cancer stem cells, indicating a novel potential therapeutic target for brain tumor treatment.
    Keywords:  ERK1/2; HIF2α; USP33; deubiquitination; glioma stem cell; hypoxia response
  3. Glia. 2022 Feb 22.
      Microglia actively promotes the growth of high-grade gliomas. Within the glioma microenvironment an amoeboid microglial morphology has been observed, however the underlying causes and the related impact on microglia functions and their tumor promoting activities is unclear. Using the advantages of the larval zebrafish model, we identified the underlying mechanism and show that microglial morphology and functions are already impaired during glioma initiation stages. The presence of pre-neoplastic HRasV12 expressing cells induces an amoeboid morphology of microglia, increases microglial numbers and decreases their motility and phagocytic activity. RNA sequencing analysis revealed lower expression levels of the actin nucleation promoting factor wasla in microglia. Importantly, a microglia specific rescue of wasla expression restores microglial morphology and functions. This results in increased phagocytosis of pre-neoplastic cells and slows down tumor progression. In conclusion, we identified a mechanism that de-activates core microglial functions within the emerging glioma microenvironment. Restoration of this mechanism might provide a way to impair glioma growth.
    Keywords:  RNA sequencing; cytoskeleton; glioblastoma; microglia; morphology; phagocytosis; wasl
  4. Brain Sci. 2022 Feb 20. pii: 291. [Epub ahead of print]12(2):
      Glioma is the most common primary brain tumor, and its prognosis is poor. Glioma cells are highly invasive to the brain parenchyma. It is difficult to achieve complete resection due to the nature of the brain tissue, and tumors that invade the parenchyma often recur. The invasiveness of tumor cells has been studied from various aspects, and the related molecular mechanisms are gradually becoming clear. Cell adhesion factors and extracellular matrix factors have a strong influence on glioma invasion. The molecular mechanisms that enhance the invasiveness of glioma stem cells, which have been investigated in recent years, have also been clarified. In addition, it has been discussed from both basic and clinical perspectives that current therapies can alter the invasiveness of tumors, and there is a need to develop therapeutic approaches to glioma invasion in the future. In this review, we will summarize the factors that influence the invasiveness of glioma based on the environment of tumor cells and tissues, and describe the impact of the treatment of glioma on invasion in terms of molecular biology, and the novel therapies for invasion that are currently being developed.
    Keywords:  extracellular matrix; glioma; glioma therapy-related invasion; invasion
  5. Biomedicines. 2022 Jan 24. pii: 246. [Epub ahead of print]10(2):
      Although hotspot mutations in isocitrate dehydrogenase (IDH) genes are associated with favorable clinical outcomes in glioma, CDKN2A/B homozygous deletion has been identified as an independent predicator of poor prognosis. Accordingly, the 2021 edition of the World Health Organization (WHO) classification of tumors of the central nervous system (CNS) has adopted this molecular feature by upgrading IDH-mutant astrocytoma to CNS WHO grade IV, even in the absence of glioblastoma-specific histological features-necrosis and microvascular proliferation. This new entity of IDH-mutant astrocytoma not only signifies an exception to the generally favorable outcome of IDH-mutant glioma, but also brings into question whether, and, if so, how, CDKN2A/B homozygous deletion overrides the anti-tumor activity of IDH mutation by promoting the proliferation of stem/neural progenitor-like cells. Understanding the mechanism by which IDH mutation requires intact tumor-suppressor genes for conferring favorable outcome may improve therapeutics.
    Keywords:  CDKN2A/B; IDH mutation; TP53; WHO classification; cell cycle; glioma; immunotherapy; stem-like cell; tumor-suppressor gene
  6. Int J Mol Sci. 2022 Feb 12. pii: 2043. [Epub ahead of print]23(4):
      Glioblastoma (GB) is the most frequent malignant brain tumor among adults and currently there is no effective treatment. This aggressive tumor grows fast and spreads through the brain causing death in 15 months. GB cells display a high mutation rate and generate a heterogeneous population of tumoral cells that are genetically distinct. Thus, the contribution of genes and signaling pathways relevant for GB progression is of great relevance. We used a Drosophila model of GB that reproduces the features of human GB and describe the upregulation of the circadian gene cry in GB patients and in a Drosophila GB model. We studied the contribution of cry to the expansion of GB cells and the neurodegeneration and premature death caused by GB, and we determined that cry is required for GB progression. Moreover, we determined that the PI3K pathway regulates cry expression in GB cells, and in turn, cry is necessary and sufficient to promote Myc accumulation in GB. These results contribute to understanding the mechanisms underlying GB malignancy and lethality, and describe a novel role of Cry in GB cells.
    Keywords:  Drosophila; EGFR; PI3K; cancer; disease model; genetics; glioma; neurodegeneration
  7. Cancers (Basel). 2022 Feb 21. pii: 1092. [Epub ahead of print]14(4):
      The central nervous system (CNS) represents a complex network of different cells, such as neurons, glial cells, and blood vessels. In tumor pathology, glial cells result in the highest number of cancers, and glioblastoma (GB) is considered the most lethal tumor in this region. The development of GB leads to the infiltration of healthy tissue through the interaction between all the elements of the brain network. This results in a GB microenvironment, a complex peritumoral hallo composed of tumor cells and several non-tumor cells (e.g., nervous cells, stem cells, fibroblasts, vascular and immune cells), which might be the principal factor for the ineffective treatment due to the fact that the microenvironment modulates the biologic status of the tumor with the increase in its evasion capacity. Crosstalk between glioma cells and the brain microenvironment finally inhibits the beneficial action of molecular pathways, favoring the development and invasion of the tumor and its increasing resistance to treatment. A deeper understanding of cell-cell interactions in the tumor microenvironment (TME) and with the tumor cells could be the basis for a more efficient therapy.
    Keywords:  cellular interactions; glioblastoma; microenvironment
  8. iScience. 2022 Feb 18. 25(2): 103842
      Glioblastoma (GBM) is the most aggressive primary brain tumor characterized by infiltrative growth of malignant glioma cells into the surrounding brain parenchyma. In this study, our analysis of GBM patient cohorts revealed a significantly higher expression of Glycosyltransferase 8 domain containing 1 (GLT8D1) compared to normal brain tissue and could be associated with impaired patient survival. Increased in vitro expression of GLT8D1 significantly enhanced migration of two different sphere-forming GBM cell lines. By in silico analysis we predicted the 3D-structure as well as the active site residues of GLT8D1. The introduction of point mutations in the predicted active site reduced its glycosyltransferase activity in vitro and consequently impaired GBM tumor cell migration. Examination of GLT8D1 interaction partners by LC-MS/MS implied proteins associated with cytoskeleton and intracellular transport as potential substrates. In conclusion, we demonstrated that the enzymatic activity of glycosyltransferase GLT8D1 promotes GBM cell migration.
    Keywords:  Biochemistry; Cancer; Cell biology; Glycobiology
  9. Clin Cancer Res. 2022 Feb 14. pii: clincanres.1933.2021. [Epub ahead of print]
      PURPOSE: Tyrosine kinase inhibitors (TKIs) have poor efficacy in patients with glioblastoma (GBM). Here, we studied whether this is predominantly due to restricted blood-brain barrier penetration or more to biological characteristics of GBM.EXPERIMENTAL DESIGN: Tumor drug concentrations of the TKI sunitinib after 2 weeks of preoperative treatment was determined in 5 patients with GBM and compared with its <em>in vitro</em> inhibitory concentration (IC50) in GBM cell lines. In addition, phosphotyrosine (pTyr) directed mass spectrometry(MS)-based proteomics was performed to evaluate sunitinib-treated versus control GBM tumors.
    RESULTS: The median tumor sunitinib concentration of 1.9 µM (range 1.0 - 3.4) was 10-fold higher than in concurrent plasma, but 3 times lower than sunitinib IC50s in GBM cell lines (median 5.4 µM, 3.0-8.5; p=0.01). pTyr-phosphoproteomic profiles of tumor samples from 4 sunitinib-treated versus 7 control patients revealed 108 significantly up- and 23 downregulated (p&lt;0.05) phosphopeptides for sunitinib-treatment, resulting in an EGFR-centered signaling network. Outlier analysis of kinase activities as a potential strategy to identify drug targets in individual tumors identified 9 kinases, including MAPK10 and INSR/IGF1R.
    CONCLUSIONS: Achieved tumor sunitinib concentrations in patients with GBM are higher than in plasma, but lower than reported for other tumor types and insufficient to significantly inhibit tumor cell growth <em>in vitro</em>. Therefore, alternative TKI dosing to increase intratumoral sunitinib concentrations might improve clinical benefit for patients with GBM. In parallel, a complex profile of kinase activity in GBM was found, supporting the potential of (phospho)proteomic analysis to identify targets for (combination) treatment.
  10. Discov Oncol. 2021 Nov 11. 12(1): 50
      PURPOSE: Heparan sulfate (HS) is one of the factors that has been suggested to be associated with angiogenesis and invasion of glioblastoma (GBM), an aggressive and fast-growing brain tumor. However, it remains unclear how HS of endothelial cells is involved in angiogenesis in glioblastoma and its prognosis. Thus, we investigated the effect of endothelial cell HS on GBM development.METHODS: We generated endothelial cell-specific knockout of Ext1, a gene encoding a glycosyltransferase and essential for HS synthesis, and murine GL261 glioblastoma cells were orthotopically transplanted. Two weeks after transplantation, we examined the tumor progression and underlying mechanisms.
    RESULTS: The endothelial cell-specific Ext1 knockout (Ext1CKO) mice exhibited reduced HS expression specifically in the vascular endothelium of the brain capillaries compared with the control wild-type (WT) mice. GBM growth was significantly suppressed in Ext1CKO mice compared with that in WT mice. After GBM transplantation, the survival rate was significantly higher in Ext1CKO mice than in WT mice. We investigated how the effect of fibroblast growth factor 2 (FGF2), which is known as an angiogenesis-promoting factor, differs between Ext1CKO and WT mice by using an in vivo Matrigel assay and demonstrated that endothelial cell-specific HS reduction attenuated the effect of FGF2 on angiogenesis.
    CONCLUSIONS: HS reduction in the vascular endothelium of the brain suppressed GBM growth and neovascularization in mice.
    Keywords:  Angiogenesis; Fibroblast growth factor 2; Glioblastoma; Heparan sulfate
  11. Mol Cancer Res. 2022 Feb 21. pii: molcanres.MCR-21-0029-A.2021. [Epub ahead of print]
      Glioblastoma is a rapidly fatal malignancy typically treated with radiation and Temozolomide (TMZ), an alkylating chemotherapeutic. These cytotoxic therapies cause oxidative stress and DNA damage, yielding a senescent-like state of replicative arrest in surviving tumor cells. Unfortunately, recurrence is inevitable, and may be driven by surviving tumor cells eventually escaping senescence. A growing number of socalled "senolytic" drugs have been recently identified that are defined by their ability to selectively eliminate senescent cells. A growing inventory of senolytic drugs are under consideration for several diseases associated with aging, inflammation, DNA damage, as well as cancer. Ablation of senescent tumor cells after radiation and chemotherapy could help mitigate recurrence by decreasing the burden of residual tumor cells at risk of recurrence. This strategy has not been previously explored for glioblastoma. We evaluated a panel of 10 previously described senolytic drugs to determine if any could exhibit selective activity against human glioblastoma persisting after exposure to radiation or TMZ. Three of the 10 drugs have known activity against BCL-XL and preferentially induced apoptosis in radiated or TMZtreated glioma. This senolytic activity was observed in 12/12 human GBM cell lines. Efficacy could not be replicated with BCL-2 inhibition or senolytic agents acting against other putative senolytic targets. Knockdown of BCL-XL decreased survival of radiated GBM cells, whereas knockdown of BCL-2 or BCL-W yielded no senolytic effect. Implications: These findings imply that molecularly heterogeneous GBM lines share selective senescence-induced Bcl-XL dependency increase the significance and translational relevance of the senolytic therapy for latent glioma.
  12. Pharmaceutics. 2022 Jan 25. pii: 279. [Epub ahead of print]14(2):
      Glioblastoma multiforme (GBM) is the most common and lethal type of brain tumor, and the clinically available approaches for its treatment are not curative. Despite the intensive research, biological barriers such as the blood-brain barrier (BBB) and tumor cell membranes are major obstacles to developing novel effective therapies. Nanoparticles (NPs) have been explored as drug delivery systems (DDS) to improve GBM therapeutic strategies. NPs can circumvent many of the biological barriers posed by this devastating disease, enhancing drug accumulation in the target site. This can be achieved by employing strategies to target the transferrin receptor (TfR), which is heavily distributed in BBB and GBM cells. These targeting strategies comprise the modification of NPs' surface with various molecules, such as transferrin (Tf), antibodies, and targeting peptides. This review provides an overview and discussion on the recent advances concerning the strategies to target the TfR in the treatment of GBM, as their benefits and limitations.
    Keywords:  active targeting; blood-brain barrier; brain delivery; functionalized nanoparticles; monoclonal antibody; surface modification; targeting peptides; transferrin
  13. Pharmaceutics. 2022 Feb 02. pii: 353. [Epub ahead of print]14(2):
      Recurrent glioblastoma (GBM) remains one of the most challenging clinical issues, with no standard treatment and effective treatment options. To evaluate the efficacy of talaporfin sodium (TS) mediated photodynamic therapy (PDT) as a new treatment for this condition, we retrospectively analyzed 70 patients who underwent surgery with PDT (PDT group) for recurrent GBM and 38 patients who underwent surgery alone (control group). The median progression-free survival (PFS) in the PDT and control groups after second surgery was 5.7 and 2.2 months, respectively (p = 0.0043). The median overall survival (OS) after the second surgery was 16.0 and 12.8 months, respectively (p = 0.031). Both univariate and multivariate analyses indicated that surgery with PDT and a preoperative Karnofsky Performance Scale were significant independent prognostic factors for PFS and OS. In the PDT group, there was no significant difference regarding PFS and OS between patients whose previous pathology before recurrence was already GBM and those who had malignant transformation to GBM from lower grade glioma. There was also no significant difference in TS accumulation in the tumor between these two groups. According to these results, additional PDT treatment for recurrent GBM could have potential survival benefits and its efficacy is independent of the pre-recurrence pathology.
    Keywords:  lower grade glioma; photodynamic therapy; photosensitizer; recurrent glioblastoma; talaporfin sodium
  14. Crit Rev Oncol Hematol. 2022 Feb 18. pii: S1040-8428(22)00065-8. [Epub ahead of print] 103641
      Glioblastoma multiforme (GBM) is a malignant brain tumor with one of the worst general survivorship cases among the existing neoplasia. This aggressiveness is due to its complex molecular heterogeneity, immunohistochemistry and genetics. The current therapeutic approach brings little contribution to the improvement of the survival of the patients. Due to that, new forms of treatment have been explored, one of them being immunotherapy. In this aspect, the inflammasome pathway, which induces inflammation and immunosuppressive tumor response, contributing to the progression of the tumor, seems to be a new alternative to improve the treatment efficacy and the survival of the patients.
    Keywords:  Exosome; Glioblastoma; Human Cancers; Immunologic Response; Inflammasome; Therapeutic; Therapeutic Targets; Tumor Microenvironment
  15. J Clin Invest. 2022 Feb 24. pii: e149258. [Epub ahead of print]
      Tumor Treating Fields (TTFields), an approved therapy for glioblastoma (GBM) and malignant mesothelioma, employ non-invasive application of low-intensity, intermediate-frequency, alternating electric fields to disrupt the mitotic spindle, leading to chromosome mis-segregation and apoptosis. Emerging evidence suggest that TTFields may also induce inflammation. However, the mechanism of this property and whether it can be harnessed therapeutically are unclear. Here, we report that TTFields induced focal disruption of the nuclear envelope, leading to cytosolic release of large micronuclei clusters that intensely recruited and activated 2 major DNA sensors - cGAS (cyclic GMP-AMP synthase) and AIM2 (absent-in-melanoma-2) - and their cognate cGAS/STING (stimulator-of-interferon-genes) and AIM2/Caspase-1 inflammasomes to produce pro-inflammatory cytokines (PICs), type-1 interferons (T1IFNs), and T1IFN-responsive genes (T1IRGs). In syngeneic murine GBM models, TTFields-treated GBM cells induced anti-tumor memory immunity and cure rate of 42% to 66% in a STING- and AIM2-dependent manner. Using single-cell and bulk RNA-sequencing of peripheral blood mononuclear cells (PBMCs), we detected robust post-TTFields activation of adaptive immunity in patients with GBM via a T1IFN-based trajectory and identified a gene panel signature of TTFields effects on T cell activation and clonal expansion. Collectively, these studies defined a therapeutic strategy using TTFields as cancer immunotherapy in GBM and potentially other solid tumors.
    Keywords:  Brain cancer; Cancer immunotherapy; Innate immunity; Oncology
  16. Proc Natl Acad Sci U S A. 2022 Mar 01. pii: e2114456119. [Epub ahead of print]119(9):
      Therapeutic strategies directed at the tumor surfaceome (TS), including checkpoint inhibitor blocking antibodies, antibody drug conjugates (ADCs), and chimeric antigen receptor T (CAR-T) cells, provide a new armament to fight cancer. However, a remaining bottleneck is the lack of strategies to comprehensively interrogate patient tumors for potential TS targets. Here, we have developed a platform (tumor surfaceome mapping [TS-MAP]) integrated with a newly curated TS classifier (SURFME) that allows profiling of primary 3D cultures and intact patient glioma tumors with preserved tissue architecture. Moreover, TS-MAP specifically identifies proteins capable of endocytosis as tractable targets for ADCs and other modalities requiring toxic payload internalization. In high-grade gliomas that remain among the most aggressive forms of cancer, we show that cellular spatial organization (2D vs. 3D) fundamentally transforms the surfaceome and endocytome (e.g., integrins, proteoglycans, semaphorins, and cancer stem cell markers) with general implications for target screening approaches, as exemplified by an ADC targeting EGFR. The TS-MAP platform was further applied to profile the surfaceome and endocytome landscape in a cohort of freshly resected gliomas. We found a highly diverse TS repertoire between patient tumors, not directly associated with grade and histology, which highlights the need for individualized approaches. Our data provide additional layers of understanding fundamental to the future development of immunotherapy strategies, as well as procedures for proteomics-based target identification and selection. The TS-MAP platform should be widely applicable in efforts aiming at a better understanding of how to harness the TS for personalized immunotherapy.
    Keywords:  glioma; immunotherapy; proteomics
  17. Brain Pathol. 2022 Feb 25. e13060
      The 2021 5th edition of the WHO Classification of Tumors of the Central Nervous System reflects the discovery of genetic alterations underlying many central nervous system (CNS) neoplasms. Insights gained from technologic advances and novel applications in molecular diagnostics, including next-generation sequencing and DNA methylation-based profiling, coupled with the recognition of clinicopathologic correlates, have prompted substantial changes to CNS tumor classification; this is particularly true for pediatric low-grade gliomas and glioneuronal tumors (pLGG/GNTs). The 2021 WHO now classifies gliomas, glioneuronal tumors and neuronal tumors into 6 families, three of which encompass pLGG/LGNTs: "Pediatric type diffuse low-grade gliomas," "circumscribed astrocytic gliomas," and "glioneuronal and neuronal tumors." Among these are six newly recognized tumor types: "diffuse astrocytoma, MYB or MYBL1-altered"; "polymorphous low grade neuroepithelial tumor of the young (PLNTY)"; "diffuse low-grade glioma-MAPK altered"; "Diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC)"; "myxoid glioneuronal tumor (MGT)"; and "multinodular and vacuolating neuronal tumor (MVNT)." We review these newly recognized entities in the context of general changes to the WHO schema, discuss implications of the new classification for treatment of pLGG/LGNT, and consider strategies for molecular testing and interpretation.
    Keywords:  2021 CNS WHO; glioneuronal tumors; low-grade gliomas
  18. Oncogene. 2022 Feb 22.
      Glioblastomas (GBMs) preferentially generate acetyl-CoA from acetate as a fuel source to promote tumor growth. O-GlcNAcylation has been shown to be elevated by increasing O-GlcNAc transferase (OGT) in many cancers and reduced O-GlcNAcylation can block cancer growth. Here, we identify a novel mechanism whereby OGT regulates acetate-dependent acetyl-CoA and lipid production by regulating phosphorylation of acetyl-CoA synthetase 2 (ACSS2) by cyclin-dependent kinase 5 (CDK5). OGT is required and sufficient for GBM cell growth and regulates acetate conversion to acetyl-CoA and lipids. Elevating O-GlcNAcylation in GBM cells increases phosphorylation of ACSS2 on Ser-267 in a CDK5-dependent manner. Importantly, we show that ACSS2 Ser-267 phosphorylation regulates its stability by reducing polyubiquitination and degradation. ACSS2 Ser-267 is critical for OGT-mediated GBM growth as overexpression of ACSS2 Ser-267 phospho-mimetic rescues growth in vitro and in vivo. Importantly, we show that pharmacologically targeting OGT and CDK5 reduces GBM growth ex vivo. Thus, the OGT/CDK5/ACSS2 pathway may be a way to target altered metabolic dependencies in brain tumors.
  19. Proc Natl Acad Sci U S A. 2022 Mar 01. pii: e2103532119. [Epub ahead of print]119(9):
      An ideal cancer therapeutic strategy involves the selective killing of cancer cells without affecting the surrounding normal cells. However, researchers have failed to develop such methods for achieving selective cancer cell death because of shared features between cancerous and normal cells. In this study, we have developed a therapeutic strategy called the cancer-specific insertions-deletions (InDels) attacker (CINDELA) to selectively induce cancer cell death using the CRISPR-Cas system. CINDELA utilizes a previously unexplored idea of introducing CRISPR-mediated DNA double-strand breaks (DSBs) in a cancer-specific fashion to facilitate specific cell death. In particular, CINDELA targets multiple InDels with CRISPR-Cas9 to produce many DNA DSBs that result in cancer-specific cell death. As a proof of concept, we demonstrate here that CINDELA selectively kills human cancer cell lines, xenograft human tumors in mice, patient-derived glioblastoma, and lung patient-driven xenograft tumors without affecting healthy human cells or altering mouse growth.
    Keywords:  CRISPR; cancer; double-strand breaks; insertion/deletion