Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
1.
Acta Neuropathol ; 142(1): 159-177, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33934221

RESUMO

Tauopathies, including Alzheimer's disease (AD) and frontotemporal lobar degeneration with Tau pathology (FTLD-tau), are a group of neurodegenerative disorders characterized by Tau hyperphosphorylation. Post-translational modifications of Tau such as phosphorylation and truncation have been demonstrated to be an essential step in the molecular pathogenesis of these tauopathies. In this work, we demonstrate the existence of a new, human-specific truncated form of Tau generated by intron 12 retention in human neuroblastoma cells and, to a higher extent, in human RNA brain samples, using qPCR and further confirming the results on a larger database of human RNA-seq samples. Diminished protein levels of this new Tau isoform are found by Westernblotting in Alzheimer's patients' brains (Braak I n = 3; Braak II n = 6, Braak III n = 3, Braak IV n = 1, and Braak V n = 10, Braak VI n = 8) with respect to non-demented control subjects (n = 9), suggesting that the lack of this truncated isoform may play an important role in the pathology. This new Tau isoform exhibits similar post-transcriptional modifications by phosphorylation and affinity for microtubule binding, but more interestingly, is less prone to aggregate than other Tau isoforms. Finally, we present evidence suggesting this new Tau isoform could be linked to the inhibition of GSK3ß, which would mediate intron 12 retention by modulating the serine/arginine rich splicing factor 2 (SRSF2). Our results show the existence of an important new isoform of Tau and suggest that further research on this less aggregation-prone Tau may help to develop future therapies for Alzheimer's disease and other tauopathies.


Assuntos
Doença de Alzheimer/metabolismo , Tauopatias/genética , Proteínas tau/química , Proteínas tau/genética , Processamento Alternativo , Linhagem Celular , Linhagem Celular Tumoral , Glicogênio Sintase Quinase 3 beta/metabolismo , Humanos , Íntrons/genética , Microtúbulos/metabolismo , Neuroblastoma/metabolismo , Fosforilação , Processamento de Proteína Pós-Traducional , Fatores de Processamento de Serina-Arginina/genética , Tauopatias/metabolismo , Proteínas tau/metabolismo
2.
Glia ; 67(2): 404-417, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30506943

RESUMO

Genetic lesions in glioblastoma (GB) include constitutive activation of PI3K and EGFR pathways to drive cellular proliferation and tumor malignancy. An RNAi genetic screen, performed in Drosophila melanogaster to discover new modulators of GB development, identified a member of the secretory pathway: kish/TMEM167A. Downregulation of kish/TMEM167A impaired fly and human glioma formation and growth, with no effect on normal glia. Glioma cells increased the number of recycling endosomes, and reduced the number of lysosomes. In addition, EGFR vesicular localization was primed toward recycling in glioma cells. kish/TMEM167A downregulation in gliomas restored endosomal system to a physiological state and altered lysosomal function, fueling EGFR toward degradation by the proteasome. These endosomal effects mirrored the endo/lysosomal response of glioma cells to Brefeldin A (BFA), but not the Golgi disruption and the ER collapse, which are associated with the undesirable toxicity of BFA in other cancers. Our results suggest that glioma growth depends on modifications of the vesicle transport system, reliant on kish/TMEM167A. Noncanonical genes in GB could be a key for future therapeutic strategies targeting EGFR-dependent gliomas.


Assuntos
Neoplasias Encefálicas/metabolismo , Proteínas de Drosophila/metabolismo , Regulação Neoplásica da Expressão Gênica/fisiologia , Glioma/metabolismo , Transporte Proteico/genética , Animais , Animais Geneticamente Modificados , Encéfalo/citologia , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Proteínas de Drosophila/genética , Drosophila melanogaster , Inibidores Enzimáticos/farmacologia , Receptores ErbB/genética , Receptores ErbB/metabolismo , Feminino , Glioma/patologia , Xenoenxertos , Humanos , Leupeptinas/farmacologia , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Masculino , Camundongos , Interferência de RNA/fisiologia
3.
Hum Mol Genet ; 25(4): 792-806, 2016 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-26721933

RESUMO

Mitochondrial anomalies have been previously reported in patients' brain and peripheral tissue, suggesting their relevance in sporadic Alzheimer's disease (AD). The present work evaluates mitochondrial function and recycling in human fibroblasts and brain biopsies. Functional studies using patients' skin fibroblasts showed slower mitochondrial membrane potential recovery after a mitochondrial insult together with alterations in lysosomes and autophagy, accompanied by an increase of oxidized and ubiquitinated proteins. Impairment in mitophagy has been proven in these cells due to diminished PARK2 and insufficient vesicle induction, accumulating depolarized mitochondria and PINK1. Augmented Δ1 PINK1 fragment levels suggest an inhibitory effect over PARK2 translocation to the mitochondria, causing the accumulation of activated PINK1. Moreover, the overexpression of PARK2 diminished ubiquitinated proteins accumulation, improves its targeting to mitochondria and potentiates autophagic vesicle synthesis. This allows the reversion of mitophagy failure reflected in the recovery of membrane potential and the decrease of PINK1 and mitochondria accumulation. Sporadic AD fibroblasts exhibited alterations similar to what it could be found in patients' hippocampal samples at early stages of the disease, where there was an accumulation of PINK1 and Δ1 PINK1 together with abnormally increased mitochondrial content. Our findings indicate that mitophagy alterations can be considered a new hallmark of sporadic AD and validate the use of fibroblasts for modelling this pathology.


Assuntos
Doença de Alzheimer/patologia , Mitocôndrias/patologia , Mitofagia/fisiologia , Ubiquitina-Proteína Ligases/biossíntese , Idoso , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/terapia , Autofagia/fisiologia , Encéfalo/metabolismo , Encéfalo/patologia , Estudos de Casos e Controles , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Lisossomos/metabolismo , Lisossomos/patologia , Masculino , Potencial da Membrana Mitocondrial/fisiologia , Pessoa de Meia-Idade , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Cultura Primária de Células , Proteínas Quinases/metabolismo , Transfecção , Ubiquitina-Proteína Ligases/administração & dosagem , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
4.
Stem Cells ; 33(3): 646-60, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25407338

RESUMO

Many solid tumors contain a subpopulation of cells with stem characteristics and these are known as cancer stem cells (CSCs) or tumor-initiating cells (TICs). These cells drive tumor growth and appear to be regulated by molecular pathway different from other cells in the tumor bulk. Here, we set out to determine whether elements of the PI3K-AKT pathway are necessary to maintain the CSC-like phenotype in breast tumor cells and for these cells to survive, bearing in mind that the identification of such elements is likely to be relevant to define future therapeutic targets. Our results demonstrate a close relationship between the maintenance of the CSC-like phenotype and the survival of these TICs. Inhibiting PI3K activity, or eliminating AKT activity, mostly that of the AKT1 isoform, produces a clear drop in TICs survival, and a reduction in the generation and growth of CD44(High) /CD24(Low) mammospheres. Surprisingly, the apoptosis of these TICs that is triggered by AKT1 deficiency is also associated with a loss of the stem cell/mesenchymal phenotype and a recovery of epithelial-like markers. Finally, we define downstream effectors that are responsible for controlling the CSC-phenotype, such as FoxO-Bim, and the death of these cells in the absence of AKT1. In summary, these data closely link the maintenance of the stem cell-like phenotype and the survival of these cells to the AKT-FoxO-Bim pathway.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Fatores de Transcrição Forkhead/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Apoptose , Proteína 11 Semelhante a Bcl-2 , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Feminino , Proteína Forkhead Box O1 , Humanos , Células MCF-7 , Fenótipo , Transdução de Sinais
5.
Neuro Oncol ; 26(7): 1213-1227, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38411438

RESUMO

BACKGROUND: Glioblastoma (GBM) is a highly malignant brain tumor that affects men more often than women. In addition, the former shows a poorer survival prognosis. To date, the reason for this sex-specific aggressiveness remains unclear. Therefore, the aim of this study is to investigate tumor processes that explain these sex differences. METHODS: This was a retrospective study of GBM patients which was stratified according to sex. A cohort with 73 tumors was analyzed with immunohistochemistry, RNA-seq and RT-qPCR to characterize differences in vascular and immunological profiles. Transcriptomic profiling, gene set enrichment analysis, and pathway enrichment analysis were used for discovering molecular pathways predominant in each group. We further investigated the therapeutic effect of bevacizumab (vascular endothelial growth factor A (VEGFA) blocking antibody) in a retrospective GBM cohort (36 tumors) based on sex differences. RESULTS: We found that under hypoxic tumor conditions, 2 distinct tumor immuno-angiogenic ecosystems develop linked to sex differences and ESR1 expression is generated. One of these subgroups, which includes male patients with low ESR1 expression, is characterized by vascular fragility associated with the appearance of regions of necrosis and high inflammation (called necroinflamed tumors). This male-specific tumor subtype shows high inflammation related to myeloid-derived suppressor cells infiltration. Using this stratification, we identified a possible group of patients who could respond to bevacizumab (BVZ) and revealed a genetic signature that may find clinical applications as a predictor of those who may benefit most from this treatment. CONCLUSIONS: This study provides a stratification based on the sexual differences in GBM, which associates the poor prognosis with the presence of immunosuppressive myeloid cells in the necrotic areas. This new stratification could change the current prognosis of GBM and identifies those who respond to BVZ treatment.


Assuntos
Bevacizumab , Neoplasias Encefálicas , Glioblastoma , Necrose , Humanos , Bevacizumab/uso terapêutico , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Glioblastoma/metabolismo , Masculino , Feminino , Estudos Retrospectivos , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/metabolismo , Prognóstico , Pessoa de Meia-Idade , Antineoplásicos Imunológicos/uso terapêutico , Inflamação/patologia , Inflamação/tratamento farmacológico , Idoso , Adulto , Inibidores da Angiogênese/uso terapêutico , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/genética , Seguimentos , Caracteres Sexuais , Taxa de Sobrevida
6.
Hum Mol Genet ; 20(14): 2807-22, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21531789

RESUMO

Friedreich's ataxia (FRDA) is an autosomal recessive disease caused by mutations that produce a deficiency in frataxin. Despite the importance of neurodegeneration in FRDA, little is known about the consequences of frataxin deficiency in neuronal cells. Here we describe a neuronal cell model for FRDA based on the use of lentiviral vectors that carry minigenes encoding frataxin-specific shRNAs that silence the expression of this gene. These lentivectors can knockdown frataxin expression in human neuroblastoma SH-SY5Y cells, which results in large-scale cell death in differentiated neuron-like cells but not in undifferentiated neuroblastoma cells. Frataxin-deficient neuron-like cells appear to die through apoptosis that is accompanied by up-regulation of p53, PUMA and Bax and activation of caspase-3. No significant autophagy is observed in frataxin-deficient neuron-like cells and the pharmacological activation of autophagy does not significantly increase neuronal cell death in response to the frataxin deficiency. Cell death triggered by frataxin knockdown can be impaired by interference with p53, caspase inhibitors and gene transfer of FXN. These results suggest that frataxin gene silencing in human neuron-like cells may constitute a useful cell model to characterize the molecular changes triggered by frataxin deficiency in neurons, as well as to search for therapies that may protect against neurodegeneration.


Assuntos
Apoptose , Inativação Gênica , Proteínas de Ligação ao Ferro/biossíntese , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Linhagem Celular , Ataxia de Friedreich/genética , Ataxia de Friedreich/metabolismo , Ataxia de Friedreich/terapia , Humanos , Proteínas de Ligação ao Ferro/genética , Modelos Biológicos , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo , Frataxina
7.
Neuroscience ; 518: 38-53, 2023 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-35272005

RESUMO

Tauopathies are a group of neurodegenerative diseases among which are many of the most prevalent and with higher incidence worldwide, such as Alzheimer's disease (AD). According to the World Health Organization, this set of diseases will continue to increase their incidence, affecting millions of people by 2050. All of them are characterized by aberrant aggregation of tau protein in neurons and glia that are distributed in different brain regions according to their susceptibility. Numerous studies reveal that synaptic regulation not only has a neuronal component, but glia plays a fundamental role in it beyond its neuroinflammatory role. Despite this, it has not been emphasized how the glial inclusions of tau in this cell type directly affect this and many other essential functions, whose alterations have been related to the development of tauopathies. In this way, this review shows how tau inclusions in glia influence the synaptic dysfunctions that result in the cognitive symptoms characteristic of tauopathies. Thus, the mechanisms affected by inclusions in neurons, astrocytes, and oligodendrocytes are unraveled.


Assuntos
Doença de Alzheimer , Tauopatias , Humanos , Proteínas tau/metabolismo , Tauopatias/metabolismo , Neuroglia/metabolismo , Neurônios/metabolismo , Doença de Alzheimer/metabolismo , Encéfalo/metabolismo
8.
Acta Neuropathol Commun ; 11(1): 79, 2023 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-37165457

RESUMO

Glial-origin brain tumors, including glioblastomas (GBM), have one of the worst prognoses due to their rapid and fatal progression. From an oncological point of view, advances in complete surgical resection fail to eliminate the entire tumor and the remaining cells allow a rapid recurrence, which does not respond to traditional therapeutic treatments. Here, we have reviewed new immunotherapy strategies in association with the knowledge of the immune micro-environment. To understand the best lines for the future, we address the advances in the design of neoantigen vaccines and possible new immune modulators. Recently, the efficacy and availability of vaccine development with different formulations, especially liposome plus mRNA vaccines, has been observed. We believe that the application of new strategies used with mRNA vaccines in combination with personalized medicine (guided by different omic's strategies) could give good results in glioma therapy. In addition, a large part of the possible advances in new immunotherapy strategies focused on GBM may be key improving current therapies of immune checkpoint inhibitors (ICI), given the fact that this type of tumor has been highly refractory to ICI.


Assuntos
Neoplasias Encefálicas , Vacinas Anticâncer , Glioblastoma , Glioma , Humanos , Glioblastoma/patologia , Vacinas Anticâncer/uso terapêutico , Fatores Imunológicos , Glioma/tratamento farmacológico , Imunoterapia/métodos , Neoplasias Encefálicas/patologia , Microambiente Tumoral
9.
Neuroscientist ; 28(3): 222-237, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-33446074

RESUMO

The brain is endowed with a unique cellular composition and organization, embedded within a vascular network and isolated from the circulating blood by a specialized frontier, the so-called blood-brain barrier (BBB), which is necessary for its proper function. Recent reports have shown that increments in the permeability of the blood vessels facilitates the entry of toxic components and immune cells to the brain parenchyma and alters the phenotype of the supporting astrocytes. All of these might contribute to the progression of different pathologies such as brain cancers or neurodegenerative diseases. Although it is well known that BBB breakdown occurs due to pericyte malfunctioning or to the lack of stability of the blood vessels, its participation in the diverse neural diseases needs further elucidation. This review summarizes what it is known about BBB structure and function and how its instability might trigger or promote neuronal degeneration and glioma progression, with a special focus on the role of pericytes as key modulators of the vasculature. Moreover, we will discuss some recent reports that highlights the participation of the BBB alterations in glioma growth. This pan-disease analysis might shed some light into these otherwise untreatable diseases and help to design better therapeutic approaches.


Assuntos
Doenças do Sistema Nervoso Central , Glioma , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Glioma/metabolismo , Glioma/patologia , Humanos , Pericitos/fisiologia
10.
Neurotherapeutics ; 19(1): 408-420, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35099769

RESUMO

Glioblastomas (GBMs) are the most frequent and highly aggressive brain tumors, being resistant to all cytotoxic and molecularly targeted agents tested so far. There is, therefore, an urgent need to find novel therapeutic approaches and/or alternative targets to bring treatment options to patients. Here, we first show that GBMs express high levels of N-MYC protein, a transcription factor involved in normal brain development. A novel stapled peptide designed to specifically target N-MYC protein monomer, IDP-410, is able to impair the formation of N-MYC/MAX complex and reduce the stability of N-MYC itself. As a result, the viability of GBM cells is compromised. Moreover, the efficacy is found dependent on the levels of expression of N-MYC. Finally, we demonstrate that IDP-410 reduces GBM growth in vivo when administered systemically, both in subcutaneous and intracranial xenografts, reducing the vascularization of the tumors, highlighting a potential relationship between the function of N-MYC and the expression of mesenchymal/angiogenic genes. Overall, our results strengthen the view of N-MYC as a therapeutic target in GBM and strongly suggest that IDP-410 could be further developed to become a first-in-class inhibitor of N-MYC protein, affecting not only tumor cell proliferation and survival, but also the interplay between GBM cells and their microenvironment.


Assuntos
Neoplasias Encefálicas , Glioblastoma , Neoplasias Encefálicas/genética , Linhagem Celular Tumoral , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Humanos , Proteína Proto-Oncogênica N-Myc/genética , Proteína Proto-Oncogênica N-Myc/metabolismo , Proteína Proto-Oncogênica N-Myc/uso terapêutico , Neovascularização Patológica/tratamento farmacológico , Peptídeos/genética , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Microambiente Tumoral
11.
Neurooncol Adv ; 4(1): vdac155, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36325374

RESUMO

Background: Temozolomide (TMZ) is an oral alkylating agent active against gliomas with a favorable toxicity profile. It is part of the standard of care in the management of glioblastoma (GBM), and is commonly used in low-grade gliomas (LGG). In-silico mathematical models can potentially be used to personalize treatments and to accelerate the discovery of optimal drug delivery schemes. Methods: Agent-based mathematical models fed with either mouse or patient data were developed for the in-silico studies. The experimental test beds used to confirm the results were: mouse glioma models obtained by retroviral expression of EGFR-wt/EGFR-vIII in primary progenitors from p16/p19 ko mice and grown in-vitro and in-vivo in orthotopic allografts, and human GBM U251 cells immobilized in alginate microfibers. The patient data used to parametrize the model were obtained from the TCGA/TCIA databases and the TOG clinical study. Results: Slow-growth "virtual" murine GBMs benefited from increasing TMZ dose separation in-silico. In line with the simulation results, improved survival, reduced toxicity, lower expression of resistance factors, and reduction of the tumor mesenchymal component were observed in experimental models subject to long-cycle treatment, particularly in slowly growing tumors. Tissue analysis after long-cycle TMZ treatments revealed epigenetically driven changes in tumor phenotype, which could explain the reduction in GBM growth speed. In-silico trials provided support for implementation methods in human patients. Conclusions: In-silico simulations, in-vitro and in-vivo studies show that TMZ administration schedules with increased time between doses may reduce toxicity, delay the appearance of resistances and lead to survival benefits mediated by changes in the tumor phenotype in slowly-growing GBMs.

12.
Mol Ther ; 18(2): 394-403, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19935779

RESUMO

Reversible immortalization holds great potential for primary tissue expansion to develop cell-based therapies as well as for basic research. Human olfactory ensheathing glia (hOEG) are promising candidates for treating spinal cord injury and for studying extrinsic neuroregenerative mechanisms. We used lentivectors with Cre/loxP technology to achieve reversible gene transfer of BMI1, SV40 large T antigen (TAg), a short hairpin RNA against p53 (shp53), and the catalytic subunit of telomerase (TERT) in primary cultures of hOEG from human donor cadaver olfactory bulbs. Several combinations of these genes were able to immortalize hOEG, conserving their antigenic markers and neuroregenerative properties but only those transduced by BMI1/TERT did not accumulate karyotypic alterations or increase senescence marker levels. Strikingly, these were also the only cells which continued to proliferate after transgene removal by Cre recombinase delivery, whereas hOEG immortalized by shp53 or TAg in combination with TERT entered into growth arrest and died. These data support the idea that immortalization and halting senescent changes are separate processes; hOEG immortalized by BMI1/TERT can revert back to their former primary cell replicative state when deimmortalized, whereas those transduced by the other combinations depend on the presence of these transgenes to maintain their aberrant proliferative state.


Assuntos
Proliferação de Células , Senescência Celular/fisiologia , Bulbo Olfatório/citologia , Adolescente , Antígenos Transformantes de Poliomavirus/genética , Western Blotting , Células Cultivadas , Senescência Celular/genética , Feminino , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Cariotipagem , Lentivirus/genética , Proteínas Nucleares/genética , Complexo Repressor Polycomb 1 , Proteínas Proto-Oncogênicas/genética , Proteínas Repressoras/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Telomerase/genética , Proteína Supressora de Tumor p53/genética
13.
Oxid Med Cell Longev ; 2021: 1643631, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33510835

RESUMO

[This corrects the article DOI: 10.1155/2017/9302761.].

14.
Cancer Res ; 81(8): 2142-2156, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33593822

RESUMO

The extraordinary plasticity of glioma cells allows them to contribute to different cellular compartments in tumor vessels, reinforcing the vascular architecture. It was recently revealed that targeting glioma-derived pericytes, which represent a big percentage of the mural cell population in aggressive tumors, increases the permeability of the vessels and improves the efficiency of chemotherapy. However, the molecular determinants of this transdifferentiation process have not been elucidated. Here we show that mutations in EGFR stimulate the capacity of glioma cells to function as pericytes in a BMX- (bone marrow and X-linked) and SOX9-dependent manner. Subsequent activation of platelet-derived growth factor receptor beta in the vessel walls of EGFR-mutant gliomas stabilized the vasculature and facilitated the recruitment of immune cells. These changes in the tumor microenvironment conferred a growth advantage to the tumors but also rendered them sensitive to pericyte-targeting molecules such as ibrutinib or sunitinib. In the absence of EGFR mutations, high-grade gliomas were enriched in blood vessels, but showed a highly disrupted blood-brain barrier due to the decreased BMX/SOX9 activation and pericyte coverage, which led to poor oxygenation, necrosis, and hypoxia. Overall, these findings identify EGFR mutations as key regulators of the glioma-to-pericyte transdifferentiation, highlighting the intricate relationship between the tumor cells and their vascular and immune milieu. Our results lay the foundations for a vascular-dependent stratification of gliomas and suggest different therapeutic vulnerabilities determined by the genetic status of EGFR. SIGNIFICANCE: This study identifies the EGFR-related mechanisms that govern the capacity of glioma cells to transdifferentiate into pericytes, regulating the vascular and immune phenotypes of the tumors. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/8/2142/F1.large.jpg.


Assuntos
Neoplasias Encefálicas/irrigação sanguínea , Transdiferenciação Celular , Microambiente Celular , Glioma/irrigação sanguínea , Mutação , Pericitos/fisiologia , Adenina/análogos & derivados , Adenina/farmacologia , Inibidores da Angiogênese/farmacologia , Animais , Vasos Sanguíneos/metabolismo , Vasos Sanguíneos/patologia , Barreira Hematoencefálica/metabolismo , Medula Óssea , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Cromossomos Humanos X , Receptores ErbB/genética , Glioma/imunologia , Glioma/patologia , Humanos , Imunidade Celular , Isocitrato Desidrogenase/genética , Camundongos , Pericitos/efeitos dos fármacos , Pericitos/metabolismo , Piperidinas/farmacologia , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Fatores de Transcrição SOX9 , Sunitinibe/farmacologia , Hipóxia Tumoral , Microambiente Tumoral
15.
Br J Haematol ; 148(1): 59-68, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19804454

RESUMO

Gain-of-function mutations of kit tyrosine kinase receptor are associated with mastocytosis. Two subclones of the HMC1 mast leukaemia cell line were used; both express an identical KIT allele-specific regulatory type mutation (V560G), but differ in that one also expresses an enzymatic site type mutation (D816V) that confers on them resistance to imatinib mesylate tyrosine kinase inhibitor. In both cell lines, proliferation was suppressed and apoptosis induced by the combination of KIT gene silencing and alpha-tocopherol succinate (alpha-TOS), a derivate of alpha-tocopherol, also known as vitamin E. Furthermore, HMC1 cells with decreased kit levels by KIT silencing, failed to form tumours when xenotransplanted into immunocompromised mice and the animals were treated systemically with alpha-TOS. Targeting kit in the presence of alpha-TOS represents a new approach against proliferation of human mast leukaemia cell lines.


Assuntos
Terapia Genética/métodos , Mastocitose/terapia , Proteínas Proto-Oncogênicas c-kit/genética , alfa-Tocoferol/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Transformação Celular Neoplásica/genética , Terapia Combinada , Técnicas de Silenciamento de Genes , Inativação Gênica , Humanos , Mastocitose/patologia , Camundongos , Camundongos Nus , Mutação , Transplante de Neoplasias , Transplante Heterólogo , Células Tumorais Cultivadas
16.
Cancers (Basel) ; 12(6)2020 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-32570988

RESUMO

Brain tumors encompass a diverse group of neoplasias arising from different cell lineages. Tumors of glial origin have been the subject of intense research because of their rapid and fatal progression. From a clinical point of view, complete surgical resection of gliomas is highly difficult. Moreover, the remaining tumor cells are resistant to traditional therapies such as radio- or chemotherapy and tumors always recur. Here we have revised the new genetic and epigenetic classification of gliomas and the description of the different transcriptional subtypes. In order to understand the progression of the different gliomas we have focused on the interaction of the plastic tumor cells with their vasculature-rich microenvironment and with their distinct immune system. We believe that a comprehensive characterization of the glioma microenvironment will shed some light into why these tumors behave differently from other cancers. Furthermore, a novel classification of gliomas that could integrate the genetic background and the cellular ecosystems could have profound implications in the efficiency of current therapies as well as in the development of new treatments.

17.
Cancers (Basel) ; 12(1)2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31947645

RESUMO

Despite the high frequency of EGFR and TP53 genetic alterations in gliomas, little is known about their crosstalk during tumor progression. Here, we described a mutually exclusive distribution between mutations in these two genes. We found that wild-type p53 gliomas are more aggressive than their mutant counterparts, probably because the former accumulate amplifications and/or mutations in EGFR and show a stronger activation of this receptor. In addition, we identified a series of genes associated with vesicular trafficking of EGFR in p53 wild-type gliomas. Among these genes, TMEM167A showed the strongest implication in overall survival in this group of tumors. In agreement with this observation, inhibition of TMEM167A expression impaired the subcutaneous and the intracranial growth of wild-type p53 gliomas, regardless of the presence of EGFR mutations. In the absence of p53 mutations, TMEM167A knockdown reduced the acidification of intracellular vesicles, affecting the autophagy process and impairing EGFR trafficking and signaling. This effect was mimicked by an inhibitor of the vacuolar ATPase. We propose that the increased aggressiveness of wild-type p53 gliomas might be due to the increase in growth factor signaling activity, which depends on the regulation of vesicular trafficking by TMEM167A.

18.
Redox Biol ; 30: 101425, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31918259

RESUMO

Transcription factor NRF2 orchestrates a cellular defense against oxidative stress and, so far, has been involved in tumor progression by providing a metabolic adaptation to tumorigenic demands and resistance to chemotherapeutics. In this study, we discover that NRF2 also propels tumorigenesis in gliomas and glioblastomas by inducing the expression of the transcriptional co-activator TAZ, a protein of the Hippo signaling pathway that promotes tumor growth. The expression of the genes encoding NRF2 (NFE2L2) and TAZ (WWTR1) showed a positive correlation in 721 gliomas from The Cancer Genome Atlas database. Moreover, NRF2 and TAZ protein levels also correlated in immunohistochemical tissue arrays of glioblastomas. Genetic knock-down of NRF2 decreased, while NRF2 overexpression or chemical activation with sulforaphane, increased TAZ transcript and protein levels. Mechanistically, we identified several NRF2-regulated functional enhancers in the regulatory region of WWTR1. The relevance of the new NRF2/TAZ axis in tumorigenesis was demonstrated in subcutaneous and intracranial grafts. Thus, intracranial inoculation of NRF2-depleted glioma stem cells did not develop tumors as determined by magnetic resonance imaging. Forced TAZ overexpression partly rescued both stem cell growth in neurospheres and tumorigenicity. Hence, NRF2 not only enables tumor cells to be competent to proliferate but it also propels tumorigenesis by activating the TAZ-mediated Hippo transcriptional program.


Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Transativadores/genética , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Bases de Dados Genéticas , Feminino , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Glioblastoma/metabolismo , Células HEK293 , Via de Sinalização Hippo , Humanos , Masculino , Camundongos , Transplante de Neoplasias , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Análise Serial de Tecidos , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional
19.
Cancers (Basel) ; 12(11)2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-33147752

RESUMO

BACKGROUND: Gliomas remain refractory to all attempted treatments, including those using immune checkpoint inhibitors. The characterization of the tumor (immune) microenvironment has been recognized as an important challenge to explain this lack of response and to improve the therapy of glial tumors. METHODS: We designed a prospective analysis of the immune cells of gliomas by flow cytometry. Tumors with or without isocitrate dehydrogenase 1/2 (IDH1/2) mutations were included in the study. The genetic profile and the presence of different molecular and cellular features of the gliomas were analyzed in parallel. The findings were validated in syngeneic mouse models. RESULTS: We observed that few immune cells infiltrate mutant IDH1/2 gliomas whereas the immune content of IDH1/2 wild-type tumors was more heterogeneous. Some of them contained an important immune infiltrate, particularly enriched in myeloid cells with immunosuppressive features, but others were more similar to mutant IDH1/2 gliomas, with few immune cells and a less immunosuppressive profile. Notably, we observed a direct correlation between the percentage of leukocytes and the presence of vascular alterations, which were associated with a reduced expression of Tau, a microtubule-binding protein that controls the formation of tumor vessels in gliomas. Furthermore, overexpression of Tau was able to reduce the immune content in orthotopic allografts of GL261 cells, delaying tumor growth. CONCLUSIONS: We have confirmed the reduced infiltration of immune cells in IDH1/2 mutant gliomas. By contrast, in IDH1/2 wild-type gliomas, we have found a direct correlation between the presence of vascular alterations and the entrance of leukocytes into the tumors. Interestingly, high levels of Tau inversely correlated with the vascular and the immune content of gliomas. Altogether, our results could be exploited for the design of more successful clinical trials with immunomodulatory molecules.

20.
Sci Transl Med ; 12(527)2020 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-31969485

RESUMO

Gliomas that express the mutated isoforms of isocitrate dehydrogenase 1/2 (IDH1/2) have better prognosis than wild-type (wt) IDH1/2 gliomas. However, how these mutant (mut) proteins affect the tumor microenvironment is still a pending question. Here, we describe that the transcription of microtubule-associated protein TAU (MAPT), a gene that has been classically associated with neurodegenerative diseases, is epigenetically controlled by the balance between wt and mut IDH1/2 in mouse and human gliomas. In IDH1/2 mut tumors, we found high expression of TAU that decreased with tumor progression. Furthermore, MAPT was almost absent from tumors with epidermal growth factor receptor (EGFR) mutations, whereas its trancription negatively correlated with overall survival in gliomas carrying wt or amplified (amp) EGFR We demonstrated that the overexpression of TAU, through the stabilization of microtubules, impaired the mesenchymal/pericyte-like transformation of glioma cells by blocking EGFR, nuclear factor kappa-light-chain-enhancer of activated B (NF-κB) and the transcriptional coactivator with PDZ-binding motif (TAZ). Our data also showed that mut EGFR induced a constitutive activation of this pathway, which was no longer sensitive to TAU. By inhibiting the transdifferentiation capacity of EGFRamp/wt tumor cells, TAU protein inhibited angiogenesis and favored vascular normalization, decreasing glioma aggressiveness and increasing their sensitivity to chemotherapy.


Assuntos
Receptores ErbB/metabolismo , Glioma/metabolismo , Isocitrato Desidrogenase/metabolismo , Proteínas tau/metabolismo , Animais , Western Blotting , Linhagem Celular , Células Endoteliais/metabolismo , Receptores ErbB/genética , Glioma/genética , Humanos , Imuno-Histoquímica , Isocitrato Desidrogenase/genética , Camundongos , Mutação/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas tau/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA