scholarly journals MODL-25. REPLICATION REPAIR DEFICIENT MOUSE MODELS PROVIDE INSIGHT ON HYPERMUTANT BRAIN TUMOURS, MECHANISMS OF IMMUNE EVASION, AND COMBINATORIAL IMMUNOTHERAPY

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii416-iii416
Author(s):  
Melissa Galati ◽  
Li Li ◽  
Sumedha Sudhaman ◽  
Tatiana Lipman ◽  
Lucie Stengs ◽  
...  
Keyword(s):  
Mouse Model ◽  
Brain Tumours ◽  
Checkpoint Inhibitors ◽  
Therapeutic Interventions ◽  
Normal Brain ◽  
Transplanted Tumors ◽  
Repair Deficiency ◽  
Combinatorial Immunotherapy ◽  
Normal Brain Development

Abstract Replication repair deficiency (RRD) is the leading cause of hypermutant brain tumours in children. RRD is caused by defects in one of four mismatch repair (MMR) genes and mutations in POLE or POLD1. Such tumours are resistant to common therapeutic agents and animal models are needed to study RRD in vivo and test novel therapies like immune checkpoint inhibitors (ICIs). To model RRD brain tumours specifically, we engineered a Pole mutant mouse model harbouring the S459F mutation (PoleS459F). We combined PoleS459F mice with conditional Msh2 knockout (Msh2LoxP) and Nestin-cre mice. All Nestin-cre+Msh2LoxP/LoxPPoleS459F/+ mice rapidly succumbed to posterior fossa brain tumours between 8.6 and 12.4 weeks. Importantly, tumours exhibited hallmark “ultrahypermutation” (~350 mutations/Mb) and the corresponding signatures characteristic of human combined MMR and POLE-proofreading glioblastoma. Interestingly, Nestin-cre+Msh2LoxP/LoxPPoleS459F/S459F mice failed to establish normal cerebella, suggesting such mutational loads may not support normal brain development. Furthermore, OLIG2-cre+Msh2LoxP/LoxPPoleS459F/+ mice failed to develop tumors. Tumors transplanted into syngeneic vs immunocompromised animals egrafted well orthotopically in the mouse hindbrain but significantly less efficiently when engrafted subcutaneously. Furthermore, immunocompromised and subcutaneous tumors revealed striking differences in mutational burden and clonal architecture, suggestive of nonautonomous immunoediting. Finally, anti-PD1 was sufficient to treat subcutaneously engrafted tumors in immunocompetent animals. This first mouse model of immunocompetent, hypermutant brain tumors can be used to uncover unique characteristics of RRD tumour evolution and allow for immune based therapeutic preclinical testing. Experiments to assess combinational ICIs and other therapeutic interventions in orthotopically transplanted tumors will also be presented.

scholarly journals Protein Kinase A Distribution in Meningioma

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1686 ◽  
Author(s):  
Caretta ◽  
Denaro ◽  
D’Avella ◽  
Mucignat-Caretta
Keyword(s):  
Brain Tissue ◽  
Catalytic Subunit ◽  
Therapeutic Interventions ◽  
Normal Brain ◽  
Local Concentration ◽  
Correlation Pattern ◽  
Catalytic Subunits ◽  
Tissue Specimens ◽  
Pka Catalytic Subunit

Deregulation of intracellular signal transduction pathways is a hallmark of cancer cells, clearly differentiating them from healthy cells. Differential intracellular distribution of the cAMP-dependent protein kinases (PKA) was previously detected in cell cultures and in vivo in glioblastoma and medulloblastoma. Our goal is to extend this observation to meningioma, to explore possible differences among tumors of different origins and prospective outcomes. The distribution of regulatory and catalytic subunits of PKA has been examined in tissue specimens obtained during surgery from meningioma patients. PKA RI subunit appeared more evenly distributed throughout the cytoplasm, but it was clearly detectable only in some tumors. RII was present in discrete spots, presumably at high local concentration; these aggregates could also be visualized under equilibrium binding conditions with fluorescent 8-substituted cAMP analogues, at variance with normal brain tissue and other brain tumors. The PKA catalytic subunit showed exactly overlapping pattern to RII and in fixed sections could be visualized by fluorescent cAMP analogues. Gene expression analysis showed that the PKA catalytic subunit revealed a significant correlation pattern with genes involved in meningioma. Hence, meningioma patients show a distinctive distribution pattern of PKA regulatory and catalytic subunits, different from glioblastoma, medulloblastoma, and healthy brain tissue. These observations raise the possibility of exploiting the PKA intracellular pathway as a diagnostic tool and possible therapeutic interventions.

scholarly journals Elucidation of the BMI1 interactome identifies novel regulatory roles in glioblastoma

NAR Cancer ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Verónica Freire-Benéitez ◽  
Nicola Pomella ◽  
Thomas O Millner ◽  
Anaëlle A Dumas ◽  
Maria Victoria Niklison-Chirou ◽  
...  
Keyword(s):  
Chromatin Immunoprecipitation ◽  
Protein Composition ◽  
Mrna Splicing ◽  
Cholesterol Transport ◽  
Normal Brain ◽  
Regulatory Functions ◽  
Polycomb Repressive Complex 1 ◽  
Normal Brain Development

Abstract Glioblastoma (GBM) is the most common and aggressive intrinsic brain tumour in adults. Epigenetic mechanisms controlling normal brain development are often dysregulated in GBM. Among these, BMI1, a structural component of the Polycomb Repressive Complex 1 (PRC1), which promotes the H2AK119ub catalytic activity of Ring1B, is upregulated in GBM and its tumorigenic role has been shown in vitro and in vivo. Here, we have used protein and chromatin immunoprecipitation followed by mass spectrometry (MS) analysis to elucidate the protein composition of PRC1 in GBM and transcriptional silencing of defining interactors in primary patient-derived GIC lines to assess their functional impact on GBM biology. We identify novel regulatory functions in mRNA splicing and cholesterol transport which could represent novel targetable mechanisms in GBM.

scholarly journals EXTH-35. LASER INTERSTITIAL THERMAL THERAPY INCREASES BLOOD-BRAIN BARRIER AND BLOOD-TUMOR BARRIER PERMEABILITY IN A MOUSE MODEL OF GLIOBLASTOMA

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi89-vi89
Author(s):  
Mounica Paturu ◽  
Afshin Salehi ◽  
Matthew Caine ◽  
Tatenda Mahlokozera ◽  
Hiroko Yano ◽  
...  
Keyword(s):  
Mouse Model ◽  
Blood Brain Barrier ◽  
Thermal Therapy ◽  
Brain Barrier ◽  
Therapeutic Window ◽  
Normal Brain ◽  
Human Igg ◽  
Laser Interstitial Thermal Therapy ◽  
Blood Brain

Abstract INTRODUCTION A central challenge in glioblastoma treatment is the presence of the blood-brain barrier (BBB) and blood-tumor barrier (BTB), which prevent access of drugs to the brain and tumor respectively. Recent evidence in patients suggests laser interstitial thermal therapy (LITT), used clinically for tumor ablation, locally disrupts BBB integrity, potentially creating a therapeutic window to deliver otherwise brain-impermeant agents. METHODS A mouse model for LITT, established using a Nd-YAG laser coupled to a 600 mm fiber optic and thermocouple probe, was inserted via burrhole to target the somatosensory cortex. Syngeneic GL261 tumor cells were stereotactically implanted prior to LITT. BBB and BTB permeability were assessed through measurement of fluorescein and doxorubicin after IV injection. Permeability of IV dextran (10 and 70 kDa) and human IgG was monitored by immunohistochemistry (IHC) analysis. Mechanisms of BBB breakdown in vivo were explored utilizing electron microscopy and IHC. RESULTS By fluorescein assay, LITT-induced BBB and BTB permeability began one day post-treatment and was sustained for at least 2 weeks. Additionally, both normal brain and brain tumors demonstrated an increase in Dextran 10 kDa, Dextran 70 kDa, and human IgG extravasation after IV injection in vivo. Mechanistically, we provide evidence that LITT triggers both a decrease in tight junction integrity and an increase in brain endothelial cell transcytosis. As proof-of-concept that LITT can enhance tumor delivery of systemic drugs, LITT increased IV doxorubicin permeability in brain in vivo. Moreover, LITT plus doxorubicin significantly increased survival in brain tumor-bearing mice compared to doxorubicin or LITT alone. CONCLUSIONS Our data suggest that LITT increases BBB and BTB permeability over a defined time window to large molecular weight agents, including antibodies, through multiple cellular mechanisms. Our preclinical results with LITT plus doxorubicin, which mirror a current clinical trial, indicate LITT can enhance the efficacy of systemically delivered drugs.

In Vivo Magnetic Resonance Imaging and 31P Spectroscopy of Large Human Brain Tumours at 1.5 Tesla

1988 ◽  
Vol 29 (1) ◽  
pp. 77-82 ◽  
Author(s):  
C. Thomsen ◽  
K. E. Jensen ◽  
E. Achten ◽  
O. Henriksen
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Human Brain ◽  
Brain Tumours ◽  
Surface Coil ◽  
Normal Brain ◽  
Resonance Imaging ◽  
Before And After ◽  
Human Brain Tumours

31P MR spectroscopy of human brain tumours is one feature of magnetic resonance imaging. Eight patients with large superficial brain tumours and eight healthy volunteers were examined with 31P spectroscopy using an 8 cm surface coil for volume selection. Seven frequencies were resolved in our spectra. The spectra from patients with brain tumours showed a great scatter, but generally they overlapped those obtained in normal brain tissue. No characteristic pattern of the spectra was seen in the tumours. One patient with a metastasis from a small cell carcinoma of the lung was examined before and after chemotherapy. The spectra showed considerable changes during chemotherapy. It is concluded that 31P spectroscopy using surface coils is of limited value for tumour characterization, but may add useful information in monitoring the effect of chemotherapy.

scholarly journals Engineered nanoparticles for systemic siRNA delivery to malignant brain tumours

Nanoscale ◽  
2019 ◽  
Vol 11 (42) ◽  
pp. 20045-20057 ◽  
Author(s):  
Johan Karlsson ◽  
Yuan Rui ◽  
Kristen L. Kozielski ◽  
Amanda L. Placone ◽  
Olivia Choi ◽  
...  
Keyword(s):  
Mouse Model ◽  
Gene Silencing ◽  
Blood Brain Barrier ◽  
Brain Tumours ◽  
Sirna Delivery ◽  
Engineered Nanoparticles ◽  
Brain Barrier ◽  
Blood Brain ◽  
Malignant Brain Tumours

Bioreducible nanoparticles were engineered for safe and effective systemic siRNA delivery, including crossing the blood–brain barrier to achieve in vivo gene silencing in an orthotopic glioblastoma mouse model.

scholarly journals Glucose transporter Glut1 controls diffuse invasion phenotype with perineuronal satellitosis in diffuse glioma microenvironment

2020 ◽  
Author(s):  
Masafumi Miyai ◽  
Tomohiro Kanayama ◽  
Fuminori Hyodo ◽  
Takamasa Kinoshita ◽  
Takuma Ishihara ◽  
...  
Keyword(s):  
Mouse Model ◽  
Glucose Transporter ◽  
Aerobic Glycolysis ◽  
Normal Brain ◽  
Diffuse Glioma ◽  
Loss Of Function ◽  
Human Gliomas ◽  
Glucose Transporter 1 ◽  
Transporter Glut1

Abstract Background Gliomas typically escape surgical resection and recur due to their “diffusion invasion” phenotype, enabling them to infiltrate diffusely into the normal brain parenchyma. Over the past 80 years, studies have revealed two key features of the “diffuse invasion” phenotype, designated the Scherer's secondary structure, and include perineuronal satellitosis (PS) and perivascular satellitosis (PVS). However, the mechanisms are still unknown. Methods We established a mouse glioma cell line (IG27) by manipulating the histone H3K27M mutation, frequently harboring in diffuse intrinsic pontine gliomas, that reproduced the diffusion invasion phenotype, PS and PVS, following intracranial transplantation in the mouse brain. Further, to broadly apply the results in this mouse model to human gliomas, we analyzed data from 66 glioma patients. Results Increased H3K27 acetylation in IG27 cells activated glucose transporter 1 (Glut1) expression and induced aerobic glycolysis and TCA cycle activation, leading to lactate, acetyl-CoA, and oncometabolite production irrespective of oxygen and glucose levels. Gain- and loss-of-function in vivo experiments demonstrated that Glut1 controls the PS of glioma cells, i.e., attachment to and contact with neurons. GLUT1 is also associated with early progression in glioma patients. Conclusions Targeting the transporter Glut1 suppresses the unique phenotype, “diffuse invasion” in the diffuse glioma mouse model. This work leads to promising therapeutic and potential useful imaging targets for anti-invasion in human gliomas widely.

Normal Brain Development and Aging: Quantitative Analysis at in Vivo MR Imaging in Healthy Volunteers

Radiology ◽  
2000 ◽  
Vol 216 (3) ◽  
pp. 672-682 ◽  
Author(s):  
Eric Courchesne ◽  
Heather J. Chisum ◽  
Jeanne Townsend ◽  
Angilene Cowles ◽  
James Covington ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Mr Imaging ◽  
Brain Development ◽  
Healthy Volunteers ◽  
Normal Brain ◽  
Development And Aging ◽  
Normal Brain Development

P13.10 Chemoattraction of glioma cells in a local hydrogel trap and immune control associated with improved survival and cognitive functions in a mouse model of glioblastoma resection

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii34-ii34
Author(s):  
H Castel ◽  
E Laillet De Montulle ◽  
M Dubois ◽  
F Ferracci ◽  
A Mutel ◽  
...  
Keyword(s):  
Mouse Model ◽  
Cognitive Functions ◽  
Ex Vivo ◽  
Glioma Cells ◽  
Boyden Chamber ◽  
Synthetic Analog ◽  
Normal Brain ◽  
Urotensin Ii

Abstract BACKGROUND Glioblastoma (GB) is the most aggressive brain primary tumor. The prognosis remains poor mainly due to the invasiveness of glioma cells, radio and/or chemoresistance and GB-induced immunosuppressive environment. Here, we propose to use a local delivery system based on a biocompatible hydrogel containing the chemopeptide urotensin II (hUII) or a biased synthetic analog DAB8-hUII, to “trap” GB cells, and/or to control immune cells expressing its G protein-coupled receptor UT, leading to tumor regression and neurological benefit, in a mouse model of GB resection. MATERIAL AND METHODS In vitro, invasion towards UII/analog across different hydrogels or glue of human or murine GB-GFP cell lines was evaluated in Boyden chamber and cloning ring assays. In vivo GB cells were intrastriatally xenografted, then resected while hydrogel- or glue-containing UII/analog was injected in the cavity resection. Behavioral tests, brain immunohistochemical analyses and mouse survival were then investigated. RESULTS In vitro, invasive capacity of human U87 and 42MG or murine GL261 and CT2A GB cells was stimulated by UII loaded into hydrogel-based hyaluronic acid supplemented with collagen or other chemicals, PNIPAAm-PEG, or thrombin-fibrin glue. In vivo, injection of UII- or DAB8-hUII-loaded glue into the cavity resection of GL261 and CT2A GB in C57BL/6 mice significantly improved survival compared with tumor and resected experimental conditions. Neurological status was also tested before and after GB resection. We found that GL261 and CT2A cell-bearing mice expressed altered spontaneous activity, emotion and cognitive functions. Intracavity injection of the glue improved resignation and anxiety and increased motor activity and cognition with a best cognitive recovery with hUII and DAB-8-hUII-loaded glue groups. Ex vivo brain analyses revealed high expression of UT and UII in some GB GFP-positive cells and macrophages within GB core and at the interface with the normal brain, GB cells expressing UT migrating along tortuous podocalyxin+ vascular components. In brains bearing hydrogel/hUII glue, vascularization appears modified and GFAP+ astrocytes and F4/80+ macrophages were highly recruited in the border of the cavity, compared with the other conditions. CONCLUSION A local glue containing UII may trap GB cells and remodel the tumor microenvironment responsible for survival and cognitive improvements, providing new option in the therapeutic arsenal of GB.

scholarly journals Dual Functions of Dab1 during Brain Development

2008 ◽  
Vol 29 (2) ◽  
pp. 324-332 ◽  
Author(s):  
Libing Feng ◽  
Jonathan A. Cooper
Keyword(s):  
Brain Development ◽  
Binding Sites ◽  
Tyrosine Kinases ◽  
Normal Development ◽  
The Other ◽  
Normal Brain ◽  
Phosphorylation Sites ◽  
Src Family Tyrosine Kinases ◽  
Normal Brain Development

ABSTRACT Reelin coordinates the movements of neurons during brain development by signaling through the Dab1 adaptor and Src family tyrosine kinases. Experiments with cultured neurons have shown that when Dab1 is phosphorylated on tyrosine, it activates Akt and provides a scaffold for assembling signaling complexes, including the paralogous Crk and CrkL adaptors. The roles of Akt and Dab1 complexes during development have been unclear. We have generated two Dab1 alleles, each lacking two out of the four putative tyrosine phosphorylation sites. Neither allele supports normal brain development, but each allele complements the other. Two tyrosines are required for Reelin to stimulate Dab1 phosphorylation at the other sites, to activate Akt, and to downregulate Dab1 levels. The other two tyrosines are required to stimulate a Crk/CrkL-C3G pathway. The absence of Crk/CrkL binding sites and C3G activation causes an unusual layering phenotype. These results show that Reelin-induced Akt stimulation and Dab1 turnover are not sufficient for normal development and suggest that Dab1 acts both as a kinase switch and as a scaffold for assembling signaling complexes in vivo.

scholarly journals Connexin hemichannel inhibition ameliorates epidermal pathology in a mouse model of keratitis ichthyosis deafness syndrome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caterina Sellitto ◽  
Leping Li ◽  
Thomas W. White
Keyword(s):  
Mouse Model ◽  
Skin Diseases ◽  
Point Mutations ◽  
Childhood Mortality ◽  
Therapeutic Interventions ◽  
Flufenamic Acid ◽  
Gene Encoding ◽  
Connexin Hemichannel

AbstractMutations in five different genes encoding connexin channels cause eleven clinically defined human skin diseases. Keratitis ichthyosis deafness (KID) syndrome is caused by point mutations in the GJB2 gene encoding Connexin 26 (Cx26) which result in aberrant activation of connexin hemichannels. KID syndrome has no cure and is associated with bilateral hearing loss, blinding keratitis, palmoplantar keratoderma, ichthyosiform erythroderma and a high incidence of childhood mortality. Here, we have tested whether a topically applied hemichhanel inhibitor (flufenamic acid, FFA) could ameliorate the skin pathology associated with KID syndrome in a transgenic mouse model expressing the lethal Cx26-G45E mutation. We found that FFA blocked the hemichannel activity of Cx26-G45E in vitro, and substantially reduced epidermal pathology in vivo, compared to untreated, or vehicle treated control animals. FFA did not reduce the expression of mutant connexin hemichannel protein, and cessation of FFA treatment allowed disease progression to continue. These results suggested that aberrant hemichannel activity is a major driver of skin disease in KID syndrome, and that the inhibition of mutant hemichannel activity could provide an attractive target to develop novel therapeutic interventions to treat this incurable disease.

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