bims-malgli Biomed News
on Biology of malignant gliomas
Issue of 2021‒12‒05
thirteen papers selected by
Oltea Sampetrean
Keio University

  1. Neuro Oncol. 2021 Nov 26. pii: noab263. [Epub ahead of print]
      BACKGROUND: Isocitrate Dehydrogenase 1/2 (IDH1/2) mutations are diagnostic for Astrocytoma or Oligodendroglioma, IDH-mutant. In these IDH-mutant gliomas, retinoic acid-related gene expression is commonly silenced by DNA hypermethylation. DNA demethylating agents can epigenetically reprogram IDH-mutant cells and reduce proliferation, likely by re-expression of silenced tumor suppressor pathways. We hypothesized that DNA demethylation might restore the retinoic acid pathway and slow tumor growth. This was the rationale for a preclinical evaluation combining the DNA demethylating agent, 5-Azacytidine (5-Aza), and retinoic acid pathway activation with all-trans retinoic acid (atRA) in IDH-mutant glioma.METHODS: In this study, we evaluated the effect of 5-Aza and atRA combination on cell proliferation, apoptosis and gene expression in human glioma cells. In addition, the efficacy of combination was tested in patient-derived xenograft (PDX) bearing the IDH1R132H mutation, utilizing subcutaneous and orthotopic models.
    RESULTS: 5-Aza reduced the DNA methylation profile and increased the gene expression of retinoic acid-related genes. Combination of 5-Aza and atRA reduced cell growth, increased differentiation marker expression, and apoptosis in IDH1R132H glioma cells. Mechanistically, 5-Aza sensitized IDHIR132H glioma cells to atRA via upregulation of the retinoic acid pathway. Importantly, the drug combination reduced significantly the growth rate of subcutaneous tumors, but in an orthotopic mouse model the combination did not improve survival and 5-Aza alone provided the best survival benefit.
    CONCLUSION: Use of DNA demethylating agent in combination with retinoids shows promise, but further optimization and preclinical studies are required for treatment of intracranial IDH-mutant gliomas.
    Keywords:  5-Azacytidine; DNA methylation; Glioma; IDH1 mutation; retinoic acid
  2. Front Oncol. 2021 ;11 768758
      Electromagnetic fields (EMF) raise intracellular levels of reactive oxygen species (ROS) that can be toxic to cancer cells. Because weak magnetic fields influence spin state pairing in redox-active radical electron pairs, we hypothesize that they disrupt electron flow in the mitochondrial electron transport chain (ETC). We tested this hypothesis by studying the effects of oscillating magnetic fields (sOMF) produced by a new noninvasive device involving permanent magnets spinning with specific frequency and timing patterns. We studied the effects of sOMF on ETC by measuring the consumption of oxygen (O2) by isolated rat liver mitochondria, normal human astrocytes, and several patient derived brain tumor cells, and O2 generation/consumption by plant cells with an O2 electrode. We also investigated glucose metabolism in tumor cells using 1H and 13C nuclear magnetic resonance and assessed mitochondrial alterations leading to cell death by using fluorescence microscopy with MitoTracker™ and a fluorescent probe for Caspase 3 activation. We show that sOMF of appropriate field strength, frequency, and on/off profiles completely arrest electron transport in isolated, respiring, rat liver mitochondria and patient derived glioblastoma (GBM), meningioma and diffuse intrinsic pontine glioma (DIPG) cells and can induce loss of mitochondrial integrity. These changes correlate with a decrease in mitochondrial carbon flux in cancer cells and with cancer cell death even in the non-dividing phase of the cell cycle. Our findings suggest that rotating magnetic fields could be therapeutically efficacious in brain cancers such as GBM and DIPG through selective disruption of the electron flow in immobile ETC complexes.
    Keywords:  cancer; diffuse intrinsic pontine glioma; electron transport chain; oxygen consumption; radical pair mechanism
  3. Sci Rep. 2021 Dec 03. 11(1): 23370
      Bromodomain and extraterminal domain (BET) proteins have emerged as therapeutic targets in multiple cancers, including the most common primary adult brain tumor glioblastoma (GBM). Although several BET inhibitors have entered clinical trials, few are brain penetrant. We have generated UM-002, a novel brain penetrant BET inhibitor that reduces GBM cell proliferation in vitro and in a human cerebral brain organoid model. Since UM-002 is more potent than other BET inhibitors, it could potentially be developed for GBM treatment. Furthermore, UM-002 treatment reduces the expression of cell-cycle related genes in vivo and reduces the expression of invasion related genes within the non-proliferative cells present in tumors as measured by single cell RNA-sequencing. These studies suggest that BET inhibition alters the transcriptional landscape of GBM tumors, which has implications for designing combination therapies. Importantly, they also provide an integrated dataset that combines in vitro and ex vivo studies with in vivo single-cell RNA-sequencing to characterize a novel BET inhibitor in GBM.
  4. Lancet Oncol. 2021 Nov 24. pii: S1470-2045(21)00578-7. [Epub ahead of print]
      BACKGROUND: Effective treatments are needed to improve outcomes for high-grade glioma and low-grade glioma. The activity and safety of dabrafenib plus trametinib were evaluated in adult patients with recurrent or progressive BRAFV600E mutation-positive high-grade glioma and low-grade glioma.METHODS: This study is part of an ongoing open-label, single-arm, phase 2 Rare Oncology Agnostic Research (ROAR) basket trial at 27 community and academic cancer centres in 13 countries (Austria, Belgium, Canada, France, Germany, Italy, Japan, the Netherlands, Norway, South Korea, Spain, Sweden, and the USA). The study enrolled patients aged 18 years or older with an Eastern Cooperative Oncology Group performance status of 0, 1, or 2. Patients with BRAFV600E mutation-positive high-grade glioma and low-grade glioma received dabrafenib 150 mg twice daily plus trametinib 2 mg once daily orally until unacceptable toxicity, disease progression, or death. In the high-grade glioma cohort, patients were required to have measurable disease at baseline using the Response Assessment in Neuro-Oncology high-grade glioma response criteria and have been treated previously with radiotherapy and first-line chemotherapy or concurrent chemoradiotherapy. Patients with low-grade glioma were required to have measurable non-enhancing disease (except pilocytic astrocytoma) at baseline using the Response Assessment in Neuro-Oncology low-grade glioma criteria. The primary endpoint, in the evaluable intention-to-treat population, was investigator-assessed objective response rate (complete response plus partial response for high-grade glioma and complete response plus partial response plus minor response for low-grade glioma). This trial is ongoing, but is closed for enrolment, NCT02034110.
    FINDINGS: Between April 17, 2014, and July 25, 2018, 45 patients (31 with glioblastoma) were enrolled into the high-grade glioma cohort and 13 patients were enrolled into the low-grade glioma cohort. The results presented here are based on interim analysis 16 (data cutoff Sept 14, 2020). In the high-grade glioma cohort, median follow-up was 12·7 months (IQR 5·4-32·3) and 15 (33%; 95% CI 20-49) of 45 patients had an objective response by investigator assessment, including three complete responses and 12 partial responses. In the low-grade glioma cohort, median follow-up was 32·2 months (IQR 25·1-47·8). Nine (69%; 95% CI 39-91) of 13 patients had an objective response by investigator assessment, including one complete response, six partial responses, and two minor responses. Grade 3 or worse adverse events were reported in 31 (53%) patients, the most common being fatigue (five [9%]), decreased neutrophil count (five [9%]), headache (three [5%]), and neutropenia (three [5%]).
    INTERPRETATION: Dabrafenib plus trametinib showed clinically meaningful activity in patients with BRAFV600E mutation-positive recurrent or refractory high-grade glioma and low-grade glioma, with a safety profile consistent with that in other indications. BRAFV600E testing could potentially be adopted in clinical practice for patients with glioma.
    FUNDING: Novartis.
  5. Exp Cell Res. 2021 Nov 27. pii: S0014-4827(21)00505-X. [Epub ahead of print]410(1): 112949
      Glioma stem/initiating cells have been considered a major cause of tumor recurrence and therapeutic resistance. In this study, we have established a new glioma stem-like cell (GSC), named U373-GSC, from the U373 glioma cell line. The cells exhibited stemness properties, e.g., expression of stem cell markers, self-renewal activity, multi-lineage differentiating abilities, and drug resistance. Using U373-GSC and GSC-03A-a GSC clone previously established from patient tissue, we have identified a novel GSC-associated sialic acid-modified glycan commonly expressed in both cell lines. Lectin fluorescence staining showed that Maackia amurensis lectin II (MAL-II)-binding alpha2,3-sialylated glycan (MAL-SG) was highly expressed in GSCs, and drastically decreased during FBS induced differentiation to glioma cells or little in the parental cells. Treatment of GSCs by MAL-II, compared with other lectins, showed that MAL-II significantly suppresses cell viability and sphere formation via induction of cell cycle arrest and apoptosis of the GSCs. Similar effects were observed when the cells were treated with a sialyltransferase inhibitor or sialidase. Taken together, we demonstrate for the first time that MAL-SGs/alpha-2,3 sialylations are upregulated and control survival/maintenances of GSCs, and their functional inhibitions lead to apoptosis of GSCs. MAL-SG could be a potential marker and therapeutic target of GSCs; its inhibitors, such as MAL-II, may be useful for glioma treatment in the future.
    Keywords:  Cancer stem cell; Glycans; Lectin; Sialic acid; Sialylation
  6. Neurooncol Adv. 2021 Jan-Dec;3(1):3(1): vdab109
      Background: Cranial radiation therapy is essential in treating many pediatric cancers, especially brain tumors; however, its use comes with the risk of developing second malignancies. Cranial radiation-induced gliomas (RIGs) are aggressive high-grade tumors with a dismal prognosis, for which no standard therapy exists. A definitive molecular signature for RIGs has not yet been established. We sought to address this gap by performing a systematic review and meta-analysis of the molecular features of cranial RIGs.Methods: A systematic review of the literature was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles and case reports that described molecular analyses of cranial radiation-induced high-grade gliomas were identified and evaluated, and data extracted for collation.
    Results: Of 1727 records identified, 31 were eligible, containing 102 unique RIGs with molecular data. The most frequent genetic alterations in RIGs included PDGFRA or TP53 mutations, PDGFRA or CDK4 amplifications, and CDKN2A deletion, along with 1q gain, 1p loss and 13q loss. Of note, mutations in ACVR1, EGFR, H3F3A, HIST1H3B, HIST1H3C, IDH2, SMARCB1 or the TERT promoter were not observed. A comparative analysis revealed that RIGs are molecularly distinct from most other astrocytomas and gliomas and instead align most closely with the pedGBM_RTK1 subgroup of pediatric glioblastoma.
    Conclusions: This comprehensive analysis highlights the major molecular features of RIGs, demonstrates their molecular distinction from many other astrocytomas and gliomas, and reveals potential genetic drivers and therapeutic targets for this currently fatal disease.
    Keywords:  Radiation-induced glioma; cancer; molecular; pediatric; radiation
  7. Clin Cancer Res. 2021 Dec 03. pii: clincanres.2867.2021. [Epub ahead of print]
      BACKGROUND: Glioblastoma is a heterogeneous malignancy with multiple subpopulations of cancer cells present within any tumor. We present the results of a phase 1 clinical trial utilizing an autologous dendritic cell vaccine pulsed with lysate derived from a glioblastoma stem-like cell line.METHODS: Patients with newly diagnosed and recurrent glioblastoma were enrolled as separate cohorts. Eligibility criteria included a qualifying surgical resection or minimal tumor size, less than or equal to 4 mg dexamethasone daily dose, and Karnofsky score greater than or equal to 70. Vaccine treatment consisted of two phases: An induction phase with vaccine given weekly for 4 weeks, and a maintenance phase with vaccines administered every 8 weeks until depletion of supply or disease progression. Patients with newly diagnosed glioblastoma also received standard-of-care radiation and temozolomide. The primary objective for this open-label, single-institution trial was to assess the safety and tolerability of the autologous dendritic cell vaccine.
    RESULTS: For the 11 patients with newly diagnosed glioblastoma, median PFS was 8.75 months, and median OS was 20.36 months. For the 25 patients with recurrent glioblastoma, median PFS was 3.23 months, 6-month PFS was 24%, and median survival was 11.97 months. A subset of patients developed a cytotoxic T cell response as determined by an IFNγ ELISpot assay.
    CONCLUSIONS: In this trial, treatment of newly diagnosed and recurrent glioblastoma with autologous dendritic cell vaccine pulsed with lysate derived from an allogeneic stem-like cell line was safe and well-tolerated. Clinical outcomes add to the body of evidence suggesting that immunotherapy plays a role in the treatment of glioblastoma.
  8. Mol Oncol. 2021 Dec 02.
      Nutritional intervention is becoming more prevalent as adjuvant therapy for many cancers in view of the tumor dependence on external sources for some nutrients. However, little is known about the mechanisms that render cancer cells dependent on certain nutrients from the microenvironment. Herein, we report the dependence of glioma cells on exogenous cysteine/cystine, despite this amino acid being nonessential. Using several 13 C-tracers and analysis of cystathionine synthase and cystathioninase levels, we revealed that glioma cells were not able to support GSH synthesis through the transsulfuration pathway, which allows methionine to be converted to cysteine in cysteine/cystine deprived conditions. Therefore, we explored the nutritional deprivation in a mouse model of glioma. Animals subjected to a cysteine/cystine-free diet survived longer, although this increase did not attain statistical significance, with concomitant reductions in plasma glutathione and cysteine levels. At the end point, however, tumors displayed the ability to synthesize glutathione, although higher levels of oxidative stress were detected. We observed a compensation from the nutritional intervention revealed as the recovery of cysteine-related metabolites levels in plasma. Our study highlights a time window where cysteine deprivation can be exploited for additional therapeutic strategies.
    Keywords:  Glioma; cysteine; diet; glutathione; metabolism
  9. Neuro Oncol. 2021 Nov 26. pii: noab273. [Epub ahead of print]
      BACKGROUND: Historically, creating patient-derived models of lower grade glioma (LGG) has been challenging, contributing to few experimental platforms that support laboratory-based investigations of this disease. Although organoid modeling approaches have recently been employed to create in vitro models of high grade glioma (HGG), it is unknown whether this approach can be successfully applied to LGG.METHODS: In this study, we developed an optimized protocol for the establishment of organoids from LGG primary tissue samples by utilizing physiologic (5%) oxygenation conditions and employed it to produce the first known suite of these models. To assess their fidelity, we surveyed key biological features of patient-derived organoids using metabolic, genomic, histologic, and lineage marker gene expression assays.
    RESULTS: Organoid models were created with a success rate of 91% (n = 20/22) from primary tumor samples across glioma histological subtypes and tumor grades (WHO Grades 1-4), and a success rate of 87% (13/15) for WHO Grade 1-3 tumors. Patient-derived organoids recapitulated stemness, proliferative, and tumor-stromal composition profiles of their respective parental tumor specimens. Cytoarchitectural, mutational, and metabolic traits of parental tumors were also conserved. Importantly, LGG organoids were maintained in vitro for weeks to months and reanimated after biobanking without loss of integrity.
    CONCLUSIONS: We report an efficient method for producing faithful in vitro models of LGG. New experimental platforms generated through this approach are well positioned to support preclinical studies of this disease, particularly those related to tumor immunology, tumor-stroma interactions, identification of novel drug targets, and personalized assessments of treatment response profiles.
    Keywords:  glioblastoma; glioma; lower grade glioma; organoids; preclinical models
  10. PLoS One. 2021 ;16(12): e0251998
      To test the safety and efficacy of drugs via a high does drug heat map, a multi-spheroids array chip was developed by adopting a micropillar and microwell structure. In the chip, patient-derived cells were encapsulated in alginate and grown to maturity for more than 7 days to form cancer multi-spheroids. Multi-spheroids grown in conventional well plates require many cells and are easily damaged as a result of multiple pipetting during maintenance culture or experimental procedures. To address these issues, we applied a micropillar and microwell structure to the multi-spheroids array. Patient-derived cells from patients with Glioblastoma (GBM), the most common and lethal form of central nervous system cancer, were used to validate the array chip performance. After forming multi-spheroids with a diameter greater than 100μm in a 12×36 pillar array chip (25mm × 75mm), we tested 70 drug compounds (6 replicates) using a high-dose to determine safety and efficacy for drug candidates. Comparing the drug response of multi-spheroids derived from normal cells and cancer cells, we found that four compounds (Dacomitinib, Cediranib, LY2835219, BGJ398) did not show toxicity to astrocyte cell and were efficacious to patient-derived GBM cells.
  11. Neuro Oncol. 2021 Nov 26. pii: noab271. [Epub ahead of print]
      BACKGROUND: Veledimex (VDX)-regulatable interleukin-12 (IL-12) gene therapy in recurrent glioblastoma (rGBM) was reported to show tumor infiltration of CD8 + T cells, encouraging survival, but also up-regulation of immune checkpoint signaling, providing the rationale for a combination trial with immune checkpoint inhibition.METHODS: An open-label, multi-institutional, dose-escalation phase 1 trial in rGBM subjects (NCT03636477) accrued 21 subjects in 3 dose-escalating cohorts: 1- neo-adjuvant then ongoing nivolumab (1mg/kg) and VDX (10 mg) (n= 3); 2- neo-adjuvant then ongoing nivolumab (3 mg/kg) and VDX (10 mg) (n=3); and 3- neo-adjuvant then ongoing nivolumab (3 mg/kg) and VDX (20 mg) (n=15). Nivolumab was administered 7 (+/- 3) days before resection of the rGBM followed by peritumoral injection of IL-12 gene therapy. VDX was administered 3 hours before and then for 14 days after surgery. Nivolumab was administered every two weeks after surgery.
    RESULTS: Toxicities of the combination were comparable to IL-12 gene monotherapy and were predictable, dose-related and reversible upon withholding doses of VDX and/or nivolumab. VDX plasma pharmacokinetics demonstrate a dose-response relationship with effective brain tumor tissue VDX penetration and production of IL-12. IL-12 levels in serum peaked in all subjects at about Day 3 after surgery. Tumor IFNγ increased in post treatment biopsies. Median overall survival (mOS) for VDX 10 mg with nivolumab was 16.9 months and for all subjects was 9.8 months.
    CONCLUSION: The safety of this combination immunotherapy was established and has led to an ongoing phase 2 clinical trial of immune checkpoint blockade with controlled IL-12 gene therapy (NCT04006119).
    Keywords:  Immunotherapy; clinical trial; controlled gene expression; gene therapy; glioblastoma