Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
Cell ; 187(17): 4733-4750.e26, 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-38971152

RESUMO

We identify a population of Protogenin-positive (PRTG+ve) MYChigh NESTINlow stem cells in the four-week-old human embryonic hindbrain that subsequently localizes to the ventricular zone of the rhombic lip (RLVZ). Oncogenic transformation of early Prtg+ve rhombic lip stem cells initiates group 3 medulloblastoma (Gr3-MB)-like tumors. PRTG+ve stem cells grow adjacent to a human-specific interposed vascular plexus in the RLVZ, a phenotype that is recapitulated in Gr3-MB but not in other types of medulloblastoma. Co-culture of Gr3-MB with endothelial cells promotes tumor stem cell growth, with the endothelial cells adopting an immature phenotype. Targeting the PRTGhigh compartment of Gr3-MB in vivo using either the diphtheria toxin system or chimeric antigen receptor T cells constitutes effective therapy. Human Gr3-MBs likely arise from early embryonic RLVZ PRTG+ve stem cells inhabiting a specific perivascular niche. Targeting the PRTGhigh compartment and/or the perivascular niche represents an approach to treat children with Gr3-MB.


Assuntos
Meduloblastoma , Células-Tronco Neoplásicas , Humanos , Meduloblastoma/patologia , Meduloblastoma/metabolismo , Animais , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Camundongos , Rombencéfalo/metabolismo , Rombencéfalo/embriologia , Neoplasias Cerebelares/metabolismo , Neoplasias Cerebelares/patologia , Células Endoteliais/metabolismo , Nicho de Células-Tronco , Células-Tronco/metabolismo , Técnicas de Cocultura , Estruturas Embrionárias , Metencéfalo/embriologia
2.
Cell ; 181(6): 1329-1345.e24, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32445698

RESUMO

Posterior fossa A (PFA) ependymomas are lethal malignancies of the hindbrain in infants and toddlers. Lacking highly recurrent somatic mutations, PFA ependymomas are proposed to be epigenetically driven tumors for which model systems are lacking. Here we demonstrate that PFA ependymomas are maintained under hypoxia, associated with restricted availability of specific metabolites to diminish histone methylation, and increase histone demethylation and acetylation at histone 3 lysine 27 (H3K27). PFA ependymomas initiate from a cell lineage in the first trimester of human development that resides in restricted oxygen. Unlike other ependymomas, transient exposure of PFA cells to ambient oxygen induces irreversible cellular toxicity. PFA tumors exhibit a low basal level of H3K27me3, and, paradoxically, inhibition of H3K27 methylation specifically disrupts PFA tumor growth. Targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.


Assuntos
Ependimoma/genética , Ependimoma/metabolismo , Epigenoma/genética , Neoplasias Infratentoriais/genética , Neoplasias Infratentoriais/metabolismo , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Linhagem Celular , Proliferação de Células/genética , Metilação de DNA/genética , Epigenômica/métodos , Histonas/genética , Histonas/metabolismo , Humanos , Lactente , Lisina/genética , Lisina/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Mutação/genética
3.
Nature ; 609(7929): 1021-1028, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36131014

RESUMO

Medulloblastoma (MB) comprises a group of heterogeneous paediatric embryonal neoplasms of the hindbrain with strong links to early development of the hindbrain1-4. Mutations that activate Sonic hedgehog signalling lead to Sonic hedgehog MB in the upper rhombic lip (RL) granule cell lineage5-8. By contrast, mutations that activate WNT signalling lead to WNT MB in the lower RL9,10. However, little is known about the more commonly occurring group 4 (G4) MB, which is thought to arise in the unipolar brush cell lineage3,4. Here we demonstrate that somatic mutations that cause G4 MB converge on the core binding factor alpha (CBFA) complex and mutually exclusive alterations that affect CBFA2T2, CBFA2T3, PRDM6, UTX and OTX2. CBFA2T2 is expressed early in the progenitor cells of the cerebellar RL subventricular zone in Homo sapiens, and G4 MB transcriptionally resembles these progenitors but are stalled in developmental time. Knockdown of OTX2 in model systems relieves this differentiation blockade, which allows MB cells to spontaneously proceed along normal developmental differentiation trajectories. The specific nature of the split human RL, which is destined to generate most of the neurons in the human brain, and its high level of susceptible EOMES+KI67+ unipolar brush cell progenitor cells probably predisposes our species to the development of G4 MB.


Assuntos
Diferenciação Celular , Neoplasias Cerebelares , Meduloblastoma , Metencéfalo , Diferenciação Celular/genética , Linhagem da Célula , Neoplasias Cerebelares/classificação , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/patologia , Cerebelo/embriologia , Cerebelo/patologia , Subunidades alfa de Fatores de Ligação ao Core/genética , Proteínas Hedgehog/metabolismo , Histona Desmetilases , Humanos , Antígeno Ki-67/metabolismo , Meduloblastoma/classificação , Meduloblastoma/genética , Meduloblastoma/patologia , Metencéfalo/embriologia , Metencéfalo/patologia , Proteínas Musculares , Mutação , Fatores de Transcrição Otx/deficiência , Fatores de Transcrição Otx/genética , Proteínas Repressoras , Proteínas com Domínio T/metabolismo , Fatores de Transcrição
4.
J Cell Sci ; 137(5)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-37970744

RESUMO

Embryos repair wounds rapidly, with no inflammation or scarring. Embryonic wound healing is driven by the collective movement of the cells around the lesion. The cells adjacent to the wound polarize the cytoskeletal protein actin and the molecular motor non-muscle myosin II, which accumulate at the wound edge forming a supracellular cable around the wound. Adherens junction proteins, including E-cadherin, are internalized from the wound edge and localize to former tricellular junctions at the wound margin, in a process necessary for cytoskeletal polarity. We found that the cells adjacent to wounds in the Drosophila embryonic epidermis polarized Talin, a core component of cell-extracellular matrix (ECM) adhesions, which preferentially accumulated at the wound edge. Integrin knockdown and inhibition of integrin binding delayed wound closure and reduced actin polarization and dynamics around the wound. Additionally, disrupting integrins caused a defect in E-cadherin reinforcement at tricellular junctions along the wound edge, suggesting crosstalk between integrin-based and cadherin-based adhesions. Our results show that cell-ECM adhesion contributes to embryonic wound repair and reveal an interplay between cell-cell and cell-ECM adhesion in the collective cell movements that drive rapid wound healing.


Assuntos
Actinas , Integrinas , Animais , Actinas/metabolismo , Integrinas/metabolismo , Caderinas/metabolismo , Movimento Celular/fisiologia , Junções Intercelulares/metabolismo , Drosophila/metabolismo , Cicatrização/fisiologia , Adesão Celular
5.
Bioinformatics ; 38(2): 594-596, 2022 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-34390579

RESUMO

SUMMARY: Our increasing ability to resolve fine details using light microscopy is matched by an increasing need to quantify images in order to detect and measure phenotypes. Despite their central role in cell biology, many image analysis tools require a financial investment, are released as proprietary software, or are implemented in languages not friendly for beginners, and thus are used as black boxes. To overcome these limitations, we have developed PyJAMAS, an open-source tool for image processing and analysis written in Python. PyJAMAS provides a variety of segmentation tools, including watershed and machine learning-based methods; takes advantage of Jupyter notebooks for the display and reproducibility of data analyses; and can be used through a cross-platform graphical user interface or as part of Python scripts via a comprehensive application programming interface. AVAILABILITY AND IMPLEMENTATION: PyJAMAS is open-source and available at https://bitbucket.org/rfg_lab/pyjamas. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Microscopia , Software , Reprodutibilidade dos Testes , Processamento de Imagem Assistida por Computador , Idioma
7.
J Org Chem ; 82(8): 4265-4278, 2017 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-28357857

RESUMO

Selective addition of radicals to isonitriles can be harnessed for initiating reaction cascades designed to overcome the stereoelectronic restrictions on homoallylic ring expansion in alkyne reactions and to develop a new general route for the preparation of N-heteroaromatics. This method utilizes alkenes as synthetic equivalents of alkynes by coupling homoallylic ring expansion to yield the formal "6-endo" products with aromatization via stereoelectronically assisted C-C bond scission. Computational analysis of the homoallyic expansion potential energy surface reveals that the indirect 5-exo/3-exo/retro-3-exo path is faster than the direct 6-endo-trig closure, revealing the general exo-preference for the cyclization processes.

8.
Org Biomol Chem ; 15(19): 4135-4143, 2017 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-28398443

RESUMO

Chemoselective addition of radicals to isonitriles can be harnessed for initiating reaction cascades designed to overcome the stereoelectronic restrictions on homoallylic ring expansion in alkyne reactions and to develop a new general route for the preparation of N-heteroaromatics. This method utilizes alkenes as synthetic equivalents of alkynes by coupling homoallylic ring expansion to yield the formal "6-endo" products with aromatization via stereoelectronically assisted C-C bond scission. Detailed computational analysis of the individual steps of the homoallylic expansion sequence maps effects of substituents and structural constraints on this multi-step potential energy surface.

9.
Proc Natl Acad Sci U S A ; 109(18): 6993-8, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22509029

RESUMO

Vascular smooth muscle cells (VSMC) have been suggested to arise from various developmental sources during embryogenesis, depending on the vascular bed. However, evidence also points to a common subpopulation of vascular progenitor cells predisposed to VSMC fate in the embryo. In the present study, we use binary transgenic reporter mice to identify a Tie1(+)CD31(dim)vascular endothelial (VE)-cadherin(-)CD45(-) precursor that gives rise to VSMC in vivo in all vascular beds examined. This precursor does not represent a mature endothelial cell, because a VE-cadherin promoter-driven reporter shows no expression in VSMC during murine development. Blockade of Notch signaling in the Tie1(+) precursor cell, but not the VE-cadherin(+) endothelial cell, decreases VSMC investment of developing arteries, leading to localized hemorrhage in the embryo at the time of vascular maturation. However, Notch signaling is not required in the Tie1(+) precursor after establishment of a stable artery. Thus, Notch activity is required in the differentiation of a Tie1(+) local precursor to VSMC in a spatiotemporal fashion across all vascular beds.


Assuntos
Diferenciação Celular/fisiologia , Mioblastos de Músculo Liso/citologia , Mioblastos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/metabolismo , Neovascularização Fisiológica , Receptores Notch/metabolismo , Animais , Antígenos CD/genética , Artérias/embriologia , Artérias/crescimento & desenvolvimento , Artérias/metabolismo , Sequência de Bases , Caderinas/deficiência , Caderinas/genética , Diferenciação Celular/genética , Primers do DNA/genética , Feminino , Antígenos Comuns de Leucócito/deficiência , Antígenos Comuns de Leucócito/genética , Camundongos , Camundongos Transgênicos , Neovascularização Fisiológica/genética , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Gravidez , Receptor de TIE-1/metabolismo , Receptores Notch/antagonistas & inibidores , Transdução de Sinais
10.
Arterioscler Thromb Vasc Biol ; 33(3): 510-2, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23288167

RESUMO

OBJECTIVE: We have recently described that Notch activates nitric oxide (NO) signaling in the embryonic endocardium. Both Notch signaling and NO signaling have been shown to be important during adult arteriogenesis. Notch has been shown to be required for remodeling of the collateral vessels, whereas NO is required for the initial vasodilatory response to ischemia. Whether Notch also has an impact on the vasodilatory phase of arteriogenesis after ischemia is not known. We tested the hypothesis that endothelial cell-Notch function is required for NO induction and vasodilation, in response to ischemia in the adult vasculature. METHODS AND RESULTS: We observed a significant decrease in NO levels in the dorsal aorta using a mouse model where Notch was inhibited in endothelial cell in a Tet-inducible fashion. In a femoral artery ligation model, inhibition of endothelial cell-Notch reduced reperfusion and NO generation, as quantified by laser Doppler perfusion imaging and by phosphoendothelial NO synthase, nitrotyrosine, and phosphovasodilator-stimulated phosphoprotein staining, respectively. CONCLUSIONS: Endothelial Notch activation is required for NO production and reactive vasodilation in a femoral artery ligation model.


Assuntos
Endotélio Vascular/metabolismo , Isquemia/metabolismo , Músculo Esquelético/irrigação sanguínea , Receptores Notch/metabolismo , Vasodilatação , Animais , Moléculas de Adesão Celular/metabolismo , Circulação Colateral , Modelos Animais de Doenças , Endotélio Vascular/fisiopatologia , Artéria Femoral/cirurgia , Membro Posterior , Isquemia/genética , Isquemia/fisiopatologia , Fluxometria por Laser-Doppler , Ligadura , Camundongos , Camundongos Transgênicos , Proteínas dos Microfilamentos/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Fosfoproteínas/metabolismo , Fosforilação , Fluxo Sanguíneo Regional , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismo
11.
Nat Cell Biol ; 25(3): 493-507, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36849558

RESUMO

How abnormal neurodevelopment relates to the tumour aggressiveness of medulloblastoma (MB), the most common type of embryonal tumour, remains elusive. Here we uncover a neurodevelopmental epigenomic programme that is hijacked to induce MB metastatic dissemination. Unsupervised analyses of integrated publicly available datasets with our newly generated data reveal that SMARCD3 (also known as BAF60C) regulates Disabled 1 (DAB1)-mediated Reelin signalling in Purkinje cell migration and MB metastasis by orchestrating cis-regulatory elements at the DAB1 locus. We further identify that a core set of transcription factors, enhancer of zeste homologue 2 (EZH2) and nuclear factor I X (NFIX), coordinates with the cis-regulatory elements at the SMARCD3 locus to form a chromatin hub to control SMARCD3 expression in the developing cerebellum and in metastatic MB. Increased SMARCD3 expression activates Reelin-DAB1-mediated Src kinase signalling, which results in a MB response to Src inhibition. These data deepen our understanding of how neurodevelopmental programming influences disease progression and provide a potential therapeutic option for patients with MB.


Assuntos
Neoplasias Cerebelares , Meduloblastoma , Humanos , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Meduloblastoma/genética , Fosforilação , Epigenômica , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismo , Moléculas de Adesão Celular Neuronais/genética , Moléculas de Adesão Celular Neuronais/metabolismo , Moléculas de Adesão Celular Neuronais/farmacologia , Neoplasias Cerebelares/genética , Epigênese Genética , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo
12.
Nat Commun ; 12(1): 1749, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33741928

RESUMO

Sonic hedgehog medulloblastoma encompasses a clinically and molecularly diverse group of cancers of the developing central nervous system. Here, we use unbiased sequencing of the transcriptome across a large cohort of 250 tumors to reveal differences among molecular subtypes of the disease, and demonstrate the previously unappreciated importance of non-coding RNA transcripts. We identify alterations within the cAMP dependent pathway (GNAS, PRKAR1A) which converge on GLI2 activity and show that 18% of tumors have a genetic event that directly targets the abundance and/or stability of MYCN. Furthermore, we discover an extensive network of fusions in focally amplified regions encompassing GLI2, and several loss-of-function fusions in tumor suppressor genes PTCH1, SUFU and NCOR1. Molecular convergence on a subset of genes by nucleotide variants, copy number aberrations, and gene fusions highlight the key roles of specific pathways in the pathogenesis of Sonic hedgehog medulloblastoma and open up opportunities for therapeutic intervention.


Assuntos
Neoplasias Cerebelares/genética , Regulação Neoplásica da Expressão Gênica , Proteínas Hedgehog/genética , Meduloblastoma/genética , Transcriptoma , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Redes Reguladoras de Genes , Variação Genética , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Transdução de Sinais/genética , Adulto Jovem
13.
Nat Med ; 26(5): 720-731, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32341580

RESUMO

Recurrent medulloblastoma and ependymoma are universally lethal, with no approved targeted therapies and few candidates presently under clinical evaluation. Nearly all recurrent medulloblastomas and posterior fossa group A (PFA) ependymomas are located adjacent to and bathed by the cerebrospinal fluid, presenting an opportunity for locoregional therapy, bypassing the blood-brain barrier. We identify three cell-surface targets, EPHA2, HER2 and interleukin 13 receptor α2, expressed on medulloblastomas and ependymomas, but not expressed in the normal developing brain. We validate intrathecal delivery of EPHA2, HER2 and interleukin 13 receptor α2 chimeric antigen receptor T cells as an effective treatment for primary, metastatic and recurrent group 3 medulloblastoma and PFA ependymoma xenografts in mouse models. Finally, we demonstrate that administration of these chimeric antigen receptor T cells into the cerebrospinal fluid, alone or in combination with azacytidine, is a highly effective therapy for multiple metastatic mouse models of group 3 medulloblastoma and PFA ependymoma, thereby providing a rationale for clinical trials of these approaches in humans.


Assuntos
Neoplasias Encefálicas/terapia , Vacinas Anticâncer/administração & dosagem , Líquido Cefalorraquidiano/efeitos dos fármacos , Ependimoma/terapia , Imunoterapia Adotiva/métodos , Meduloblastoma/terapia , Animais , Neoplasias Encefálicas/líquido cefalorraquidiano , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/patologia , Neoplasias Cerebelares/líquido cefalorraquidiano , Neoplasias Cerebelares/imunologia , Neoplasias Cerebelares/patologia , Neoplasias Cerebelares/terapia , Líquido Cefalorraquidiano/imunologia , Criança , Pré-Escolar , Sistemas de Liberação de Medicamentos/métodos , Ependimoma/líquido cefalorraquidiano , Ependimoma/imunologia , Ependimoma/patologia , Feminino , Células HEK293 , Humanos , Lactente , Injeções Intraventriculares , Masculino , Meduloblastoma/líquido cefalorraquidiano , Meduloblastoma/imunologia , Meduloblastoma/patologia , Camundongos , Metástase Neoplásica , Receptores de Antígenos Quiméricos/administração & dosagem , Receptores de Antígenos Quiméricos/genética , Receptores de Antígenos Quiméricos/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Linfócitos T/transplante , Resultado do Tratamento , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Cancer Res ; 79(22): 5799-5811, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31519687

RESUMO

Eliminating leukemic stem cells (LSC) is a sought after therapeutic paradigm for the treatment of acute myeloid leukemia (AML). While repression of aryl hydrocarbon receptor (AHR) signaling has been shown to promote short-term maintenance of primitive AML cells in culture, no work to date has examined whether altered AHR signaling plays a pathologic role in human AML or whether it contributes at all to endogenous LSC function. Here, we show AHR signaling is repressed in human AML blasts and preferentially downregulated in LSC-enriched populations within leukemias. A core set of AHR targets are uniquely repressed in LSCs across diverse genetic AML subtypes. In vitro and in vivo administration of the specific AHR agonist FICZ significantly impaired leukemic growth, promoted differentiation, and repressed self-renewal. Furthermore, LSCs suppressed a set of FICZ-responsive AHR target genes that function as tumor suppressors and promoters of differentiation. FICZ stimulation did not impair normal hematopoietic stem and progenitor (HSPC) function, and failed to upregulate a prominent LSC-specific AHR target in HSPCs, suggesting that differential mechanisms govern FICZ-induced AHR signaling manifestations in HSCs versus LSCs. Altogether, this work highlights AHR signaling suppression as a key LSC-regulating control mechanism and provides proof of concept in a preclinical model that FICZ-mediated AHR pathway activation enacts unique transcriptional programs in AML that identify it as a novel chemotherapeutic approach to selectively target human LSCs. SIGNIFICANCE: The AHR pathway is suppressed in leukemic stem cells (LSC), therefore activating AHR signaling is a potential therapeutic option to target LSCs and to treat acute myeloid leukemia.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Leucemia Mieloide Aguda/genética , Células-Tronco Neoplásicas/patologia , Receptores de Hidrocarboneto Arílico/genética , Transdução de Sinais/genética , Animais , Diferenciação Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Células-Tronco Hematopoéticas/patologia , Humanos , Leucemia Mieloide Aguda/patologia , Camundongos , Regiões Promotoras Genéticas/genética
16.
Chem Commun (Camb) ; 51(64): 12831-4, 2015 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-26165765

RESUMO

Stereoelectronic restrictions on homoallylic ring expansion in alkyne cascades can be overcome by using alkenes as synthetic equivalents of alkynes in reaction cascades that are terminated by C-C bond fragmentation. Implementation of this approach using Mn(iii)-mediated reaction of o-alkenyl isocyanides and boronic acids leads to efficient synthesis of substituted quinolines.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA