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Whereas the contribution of tumor microenvironment to the profound immune suppression of glioblastoma (GBM) is clear, tumor-cell intrinsic mechanisms that regulate resistance to CD8 T cell mediated killing are less understood. Kinases are potentially druggable targets that drive tumor progression and might influence immune response. Here, we perform an in vivo CRISPR screen to identify glioma intrinsic kinases that contribute to evasion of tumor cells from CD8 T cell recognition. The screen reveals checkpoint kinase 2 (Chek2) to be the most important kinase contributing to escape from CD8 T-cell recognition. Genetic depletion or pharmacological inhibition of Chek2 with blood-brain-barrier permeable drugs that are currently being evaluated in clinical trials, in combination with PD-1 or PD-L1 blockade, lead to survival benefit in multiple preclinical glioma models. Mechanistically, loss of Chek2 enhances antigen presentation, STING pathway activation and PD-L1 expression in mouse gliomas. Analysis of human GBMs demonstrates that Chek2 expression is inversely associated with antigen presentation and T-cell activation. Collectively, these results support Chek2 as a promising target for enhancement of response to immune checkpoint blockade therapy in GBM.

Epigenetic remodeling is a molecular hallmark of gliomas, and it has been identified as a key mediator of glioma progression. Epigenetic dysregulation contributes to gliomagenesis, tumor progression, and responses to immunotherapies, as well as determining clinical features. This epigenetic remodeling includes changes in histone modifications, chromatin structure, and DNA methylation, all of which are driven by mutations in genes such as histone 3 genes (H3C1 and H3F3A), isocitrate dehydrogenase 1/2 (IDH1/2), [alpha]-thalassemia/mental retardation, X- linked (ATRX), and additional chromatin remodelers. Although much of the initial research primarily identified how the epigenetic aberrations impacted glioma progression by solely examining the glioma cells, recent studies have aimed at establishing the role of epigenetic alterations in shaping the tumor microenvironment (TME). In this review, we discuss the mechanisms by which these epigenetic phenomena in glioma remodel the TME and how current therapies targeting epigenetic dysregulation affect the glioma immune response and therapeutic outcomes. Understanding the link between epigenetic remodeling and the glioma TME provides insights into the implementation of epigenetic-targeting therapies to improve the antitumor immune response., Introduction Gliomas are the most common type of primary tumors originating in the central nervous system (CNS) (1). They are characterized as highly heterogeneous tumors, both biologically and morphologically. Gliomas [...]

Mutant isocitrate dehydrogenase 1 (IDH1-R132H; mIDH1) is a hallmark of adult gliomas. Lower grade mIDH1 gliomas are classified into 2 molecular subgroups: 1p/19q codeletion/TERT-promoter mutations or inactivating mutations in a-thalassemia/mental retardation syndrome X-linked (ATRX) and TP53. This work focuses on glioma subtypes harboring mIDH1, TP53, and ATRX inactivation. IDH1-R132H is a gain-of-function mutation that converts a-ketoglutarate into 2-hydroxyglutarate (D-2HG). The role of D-2HG within the tumor microenvironment of mIDH1/mATRX/mTP53 gliomas remains unexplored. Inhibition of D-2HG, when used as monotherapy or in combination with radiation and temozolomide (IR/TMZ), led to increased median survival (MS) of mIDH1 glioma-bearing mice. Also, D-2HG inhibition elicited anti- mIDH1 glioma immunological memory. In response to D-2HG inhibition, PD-L1 expression levels on mIDH1-glioma cells increased to similar levels as observed in WT-IDH gliomas. Thus, we combined D-2HG inhibition/IR/TMZ with anti-PDL1 immune checkpoint blockade and observed complete tumor regression in 60% of mIDH1 glioma-bearing mice. This combination strategy reduced T cell exhaustion and favored the generation of memory [CD8.sup.+] T cells. Our findings demonstrate that metabolic reprogramming elicits anti-mIDH1 glioma immunity, leading to increased MS and immunological memory. Our preclinical data support the testing of IDH-R132H inhibitors in combination with IR/TMZ and anti-PDL1 as targeted therapy for mIDH1/mATRX/mTP53 glioma patients., Introduction Gliomas are highly infiltrative brain tumors accounting for 32% of all primary central nervous system malignancies (1). With advances in molecular biology and sequencing technologies, a distinct profile of [...]

Angiotensin Type 1 (AT1) receptors are involved in cardiovascular pathology. Lozartan, the AT1 receptor blocker, in combination with exercise has been shown to be effective in improving cardiac performance. The goal of the study was to investigate the role of AT1a receptors on cardiac function, and exercise tolerance in response to aerobic exercise using AT1a receptor knockout (AT1aKO) mice. An exercise wheel system was used for the exercise paradigm. Male (C57BL/6) wild type (WT) and AT1aKO mice were randomly assigned to four groups: WT control (n=6), WT exercise (WTEX, n=8), AT1a KO (KO) control (n=5), and AT1a KO exercise (KOEX, n=8). Mice were forced to run at a velocity of 8 m/min for 1 hour, 3d/wk, for 7 wks. Echocardiography was conducted at baseline and 7 wks. Lactate was measured during several exercise sessions. Electrolytes and cardiac histology were assessed post-sacrifice. Results showed a significant increase in ejection fraction (EF%) in KOEX (72.5±1.5%) vs. WTEX and KO control (63.4±1.2% and 63.2±2.2%, respectively). Mitral valve assessment revealed a marked decrease in E-wave velocity in WTEX compared to WT control at baseline (74±1.9 vs.90±3.5 cm/s, p<0.05), while E/A wave ratio remained unchanged. Cardiomyocyte diameter was larger in WTEX compared to KOEX (29.5±0.7 vs. 25.8±0.5 μm, p<0.05). Heart to body weight ratio was significantly higher in WTEX vs. KOEX (5.5±0.2 vs. 4.3±0.1 mg/g, p<0.001). Masson’s Trichrome staining revealed higher collagen levels in WTEX myocardium compared to WT control and KOEX (16% vs. 5%). Blood lactate accumulation values were greater at 5 and 60 min of wheel running in WTEX (4.2±0.4 and 3.9±0.5 mmol/l) vs. KOEX (3.0±0.2 and 2.9±0.2 mmol/l). A basic metabolic panel revealed higher [HCO3-] in KOEX vs. WTEX (21.7±0.6 vs. 13.7±1.8 mmol/l). Cl- was lower in KOEX compared to WTEX (102.5±2.5 vs. 113.5±2.7mmol/l, p<0.05). In conclusion, AT1aKO mice exhibited improved cardiac performance without myocardium hypertrophy, greater exercise endurance, and enhanced metabolic activity in response to chronic exercise. These results suggest that the AT1a receptor is an important mediator of exercise induced cardiac dysfunction and acid-base imbalance during exercise training. [ABSTRACT FROM AUTHOR]

Background: Gliomas are the most common primary brain tumors. High-Grade Gliomas have a median survival (MS) of 18 months, while Low-Grade Gliomas (LGGs) have an MS of approximately 7.3 years. Seventy-six percent of patients with LGG express mutated isocitrate dehydrogenase (mIDH) enzyme. Survival of these patients ranges from 1 to 15 years, and tumor mutational burden ranges from 0.28 to 3.85 somatic mutations/megabase per tumor. We tested the hypothesis that the tumor mutational burden would predict the survival of patients with tumors bearing mIDH., Methods: We analyzed the effect of tumor mutational burden on patients' survival using clinical and genomic data of 1199 glioma patients from The Cancer Genome Atlas and validated our results using the Glioma Longitudinal AnalySiS consortium., Results: High tumor mutational burden negatively correlates with the survival of patients with LGG harboring mIDH ( P = .005). This effect was significant for both Oligodendroglioma (LGG- m IDH- O ; MS = 2379 vs 4459 days in high vs low, respectively; P = .005) and Astrocytoma (LGG- m IDH- A ; MS = 2286 vs 4412 days in high vs low respectively; P = .005). There was no differential representation of frequently mutated genes (eg, TP53 , ATRX , CIC , and FUBP ) in either group. Gene set enrichment analysis revealed an enrichment in Gene Ontologies related to cell cycle, DNA-damage response in high versus low tumor mutational burden. Finally, we identified 6 gene sets that predict survival for LGG- m IDH- A and LGG- m IDH- O ., Conclusions: we demonstrate that tumor mutational burden is a powerful, robust, and clinically relevant prognostic factor of MS in mIDH patients., (© The Author(s) 2020. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Diffuse Gliomas represent 80% of brain tumors with an average survival of the most aggressive form glioblastoma (GBM) 15-22 months from the time of diagnosis. The current standard of care includes tumor resection, chemotherapy and radiation, nevertheless, the incidence of recurrence remains high and there is a critical need for developing new therapeutic strategies. T-cell mediated immunotherapy that triggers an anti-tumor T cell-mediated memory response is a promising approach since it will not only attack the primary tumor but also prevent recurrence. Multiple immunotherapeutic strategies against glioma are currently being tested in clinical trials. We have developed an immune-mediated gene therapy (Thymidine kinase plus Fms-like tyrosine kinase 3 ligand: TK/Flt3L) which induces a robust anti-tumor T cell response leading to tumor regression, long-term survival and immunological memory in GBM models. Efficacy of the anti-glioma T cell therapy is determined by anti-tumor specific effector T cells. Therefore, assessing effector T cell activation status and function are critical readouts for determining the effectiveness of the therapy. Here, we detail methodologies to evaluate tumor specific T-cell responses using a genetically engineered Sleeping Beauty transposase-mediated glioma model. We first describe the glioma model and the generation of neurospheres (NS) that express the surrogate antigen cOVA. Then, we describe functional assays to determine anti-tumor T-cell response., (© 2020 Elsevier Inc. All rights reserved.)

Despite advances in uncovering the molecular mechanisms that mediate glioma progression and the implementation of novel therapeutic modalities, patients' prognosis remains dismal. This is due to both systemic and local tumor induced immune suppression. We are particularly interested in the role played by infiltrating immunosuppressive myeloid derived suppressor cells (MDSCs) in the glioma tumor microenvironment (TME). This immunosuppressive TME also interferes with the effectiveness of immunotherapies against glioma. Development of multipronged treatment approaches is imperative when aiming to generate a robust anti-glioma immune response. Evaluating the inhibitory potential of MDSCs within the TME is an important aspect for developing effective treatments for glioma. Herein, we discuss methodology to assess the inhibitory effects of MDSCs isolated from the TME using a mouse glioma model., (© 2020 Elsevier Inc. All rights reserved.)

Aminopeptidase-A (APA) is a less well-studied enzyme of the renin-angiotensin system. We propose that it is involved in cardiac angiotensin (ANG) metabolism and its pathologies. ANG-(1-7) can ameliorate remodeling after myocardial injury. The aims of this study are to (1) develop mass spectrometric (MS) approaches for the assessment of ANG processing by APA within the myocardium; and (2) investigate the role of APA in cardiac ANG-(1-7) metabolism after myocardial infarction (MI) using sensitive MS techniques. MI was induced in C57Bl/6 male mice by ligating the left anterior descending (LAD) artery. Frozen mouse heart sections (in situ assay) or myocardial homogenates (in vitro assay) were incubated with the endogenous APA substrate, ANG II. Results showed concentration- and time-dependent cardiac formation of ANG III from ANG II, which was inhibited by the specific APA inhibitor, 4-amino-4-phosphonobutyric acid. Myocardial APA activity was significantly increased 24 h after LAD ligation (0.82 ± 0.02 vs. 0.32 ± 0.02 ρmol·min(-1)·μg(-1), MI vs. sham, P < 0.01). Both MS enzyme assays identified the presence of a new peptide, ANG-(2-7), m/z 784, which accumulated in the MI (146.45 ± 6.4 vs. 72.96 ± 7.0%, MI vs. sham, P < 0.05). Use of recombinant APA enzyme revealed that APA is responsible for ANG-(2-7) formation from ANG-(1-7). APA exhibited similar substrate affinity for ANG-(1-7) compared with ANG II {Km (ANG II) = 14.67 ± 1.6 vs. Km [ANG-(1-7)] = 6.07 ± 1.12 μmol/l, P < 0.05}. Results demonstrate a novel role of APA in ANG-(1-7) metabolism and suggest that the upregulation of APA, which occurs after MI, may deprive the heart of cardioprotective ANG-(1-7). Thus APA may serve as a potentially novel therapeutic target for management of tissue remodeling after MI.