Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 61
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Commun ; 11(1): 1407, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32179751

RESUMO

Leukaemogenic mutations commonly disrupt cellular differentiation and/or enhance proliferation, thus perturbing the regulatory programs that control self-renewal and differentiation of stem and progenitor cells. Translocations involving the Mll1 (Kmt2a) gene generate powerful oncogenic fusion proteins, predominantly affecting infant and paediatric AML and ALL patients. The early stages of leukaemogenic transformation are typically inaccessible from human patients and conventional mouse models. Here, we take advantage of cells conditionally blocked at the multipotent haematopoietic progenitor stage to develop a MLL-r model capturing early cellular and molecular consequences of MLL-ENL expression based on a clear clonal relationship between parental and leukaemic cells. Through a combination of scRNA-seq, ATAC-seq and genome-scale CRISPR-Cas9 screening, we identify pathways and genes likely to drive the early phases of leukaemogenesis. Finally, we demonstrate the broad utility of using matched parental and transformed cells for small molecule inhibitor studies by validating both previously known and other potential therapeutic targets.

2.
Science ; 367(6477): 586-590, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-32001657

RESUMO

The initiating mutations that contribute to cancer development are sometimes present in premalignant cells. Whether therapies targeting these mutations can eradicate premalignant cells is unclear. Acute myeloid leukemia (AML) is an attractive system for investigating the effect of preventative treatment because this disease is often preceded by a premalignant state (clonal hematopoiesis or myelodysplastic syndrome). In Npm1c/Dnmt3a mutant knock-in mice, a model of AML development, leukemia is preceded by a period of extended myeloid progenitor cell proliferation and self-renewal. We found that this self-renewal can be reversed by oral administration of a small molecule (VTP-50469) that targets the MLL1-Menin chromatin complex. These preclinical results support the hypothesis that individuals at high risk of developing AML might benefit from targeted epigenetic therapy in a preventative setting.

3.
Cell Rep ; 30(3): 739-754.e4, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31968250

RESUMO

Vitamin D (VD) is a known differentiating agent, but the role of VD receptor (VDR) is still incompletely described in acute myeloid leukemia (AML), whose treatment is based mostly on antimitotic chemotherapy. Here, we present an unexpected role of VDR in normal hematopoiesis and in leukemogenesis. Limited VDR expression is associated with impaired myeloid progenitor differentiation and is a new prognostic factor in AML. In mice, the lack of Vdr results in increased numbers of hematopoietic and leukemia stem cells and quiescent hematopoietic stem cells. In addition, malignant transformation of Vdr-/- cells results in myeloid differentiation block and increases self-renewal. Vdr promoter is methylated in AML as in CD34+ cells, and demethylating agents induce VDR expression. Association of VDR agonists with hypomethylating agents promotes leukemia stem cell exhaustion and decreases tumor burden in AML mouse models. Thus, Vdr functions as a regulator of stem cell homeostasis and leukemic propagation.

4.
Nat Protoc ; 15(2): 266-315, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31907453

RESUMO

Mouse models of human cancer have transformed our ability to link genetics, molecular mechanisms and phenotypes. Both reverse and forward genetics in mice are currently gaining momentum through advances in next-generation sequencing (NGS). Methodologies to analyze sequencing data were, however, developed for humans and hence do not account for species-specific differences in genome structures and experimental setups. Here, we describe standardized computational pipelines specifically tailored to the analysis of mouse genomic data. We present novel tools and workflows for the detection of different alteration types, including single-nucleotide variants (SNVs), small insertions and deletions (indels), copy-number variations (CNVs), loss of heterozygosity (LOH) and complex rearrangements, such as in chromothripsis. Workflows have been extensively validated and cross-compared using multiple methodologies. We also give step-by-step guidance on the execution of individual analysis types, provide advice on data interpretation and make the complete code available online. The protocol takes 2-7 d, depending on the desired analyses.

5.
Blood ; 135(4): 269-273, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-31697828

RESUMO

Although acquisition of leukemia-associated somatic mutations by 1 or more hematopoietic stem cells is inevitable with advancing age, its consequences are highly variable, ranging from clinically silent clonal hematopoiesis (CH) to leukemic progression. To investigate the influence of heritable factors on CH, we performed deep targeted sequencing of blood DNA from 52 monozygotic (MZ) and 27 dizygotic (DZ) twin pairs (aged 70-99 years). Using this highly sensitive approach, we identified CH (variant allele frequency ≥0.5%) in 62% of individuals. We did not observe higher concordance for CH within MZ twin pairs as compared with that within DZ twin pairs, or to that expected by chance. However, we did identify 2 MZ pairs in which both twins harbored identical rare somatic mutations, suggesting a shared cell of origin. Finally, in 3 MZ twin pairs harboring mutations in the same driver genes, serial blood samples taken 4 to 5 years apart showed substantial twin-to-twin variability in clonal trajectories. Our findings propose that the inherited genome does not exert a dominant influence on the behavior of adult CH and provide evidence that CH mutations may be acquired in utero.

6.
Nature ; 577(7789): 266-270, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31827282

RESUMO

Acute myeloid leukaemia (AML) is a heterogeneous disease characterized by transcriptional dysregulation that results in a block in differentiation and increased malignant self-renewal. Various epigenetic therapies aimed at reversing these hallmarks of AML have progressed into clinical trials, but most show only modest efficacy owing to an inability to effectively eradicate leukaemia stem cells (LSCs)1. Here, to specifically identify novel dependencies in LSCs, we screened a bespoke library of small hairpin RNAs that target chromatin regulators in a unique ex vivo mouse model of LSCs. We identify the MYST acetyltransferase HBO1 (also known as KAT7 or MYST2) and several known members of the HBO1 protein complex as critical regulators of LSC maintenance. Using CRISPR domain screening and quantitative mass spectrometry, we identified the histone acetyltransferase domain of HBO1 as being essential in the acetylation of histone H3 at K14. H3 acetylated at K14 (H3K14ac) facilitates the processivity of RNA polymerase II to maintain the high expression of key genes (including Hoxa9 and Hoxa10) that help to sustain the functional properties of LSCs. To leverage this dependency therapeutically, we developed a highly potent small-molecule inhibitor of HBO1 and demonstrate its mode of activity as a competitive analogue of acetyl-CoA. Inhibition of HBO1 phenocopied our genetic data and showed efficacy in a broad range of human cell lines and primary AML cells from patients. These biological, structural and chemical insights into a therapeutic target in AML will enable the clinical translation of these findings.

8.
Nat Commun ; 10(1): 4543, 2019 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-31586074

RESUMO

Sequencing studies of diffuse large B cell lymphoma (DLBCL) have identified hundreds of recurrently altered genes. However, it remains largely unknown whether and how these mutations may contribute to lymphomagenesis, either individually or in combination. Existing strategies to address this problem predominantly utilize cell lines, which are limited by their initial characteristics and subsequent adaptions to prolonged in vitro culture. Here, we describe a co-culture system that enables the ex vivo expansion and viral transduction of primary human germinal center B cells. Incorporation of CRISPR/Cas9 technology enables high-throughput functional interrogation of genes recurrently mutated in DLBCL. Using a backbone of BCL2 with either BCL6 or MYC, we identify co-operating genetic alterations that promote growth or even full transformation into synthetically engineered DLBCL models. The resulting tumors can be expanded and sequentially transplanted in vivo, providing a scalable platform to test putative cancer genes and to create mutation-directed, bespoke lymphoma models.


Assuntos
Linfócitos B/patologia , Linfoma Difuso de Grandes Células B/genética , Cultura Primária de Células/métodos , Animais , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Proliferação de Células/genética , Técnicas de Cocultura/métodos , Vetores Genéticos/genética , Centro Germinativo/citologia , Ensaios de Triagem em Larga Escala , Humanos , Linfoma Difuso de Grandes Células B/patologia , Camundongos , Gradação de Tumores , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-6/genética , Proteínas Proto-Oncogênicas c-myc/genética , Retroviridae/genética , Transdução Genética , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Sci Rep ; 9(1): 9139, 2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31235852

RESUMO

Acute myeloid leukemia (AML) is a heterogeneous disease with respect to its genetic and molecular basis and to patients´ outcome. Clinical, cytogenetic, and mutational data are used to classify patients into risk groups with different survival, however, within-group heterogeneity is still an issue. Here, we used a robust likelihood-based survival modeling approach and publicly available gene expression data to identify a minimal number of genes whose combined expression values were prognostic of overall survival. The resulting gene expression signature (4-GES) consisted of 4 genes (SOCS2, IL2RA, NPDC1, PHGDH), predicted patient survival as an independent prognostic parameter in several cohorts of AML patients (total, 1272 patients), and further refined prognostication based on the European Leukemia Net classification. An oncogenic role of the top scoring gene in this signature, SOCS2, was investigated using MLL-AF9 and Flt3-ITD/NPM1c driven mouse models of AML. SOCS2 promoted leukemogenesis as well as the abundance, quiescence, and activity of AML stem cells. Overall, the 4-GES represents a highly discriminating prognostic parameter in AML, whose clinical applicability is greatly enhanced by its small number of genes. The newly established role of SOCS2 in leukemia aggressiveness and stemness raises the possibility that the signature might even be exploitable therapeutically.

11.
Blood ; 134(4): 383-388, 2019 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-31186273

RESUMO

Activating mutations in FMS-like tyrosine kinase receptor-3 (FLT3) and Nucleophosmin-1 (NPM1) are most frequent alterations in acute myeloid leukemia (AML), and are often coincidental. The mutational status of NPM1 has strong prognostic relevance to patients with point mutations of the FLT3 tyrosine kinase domain (TKD), but the biological mechanism underlying this effect remains unclear. In the present study, we investigated the effect of the coincidence of NPM1c and FLT3-TKD. Although expression of FLT3-TKD is not sufficient to induce a disease in mice, coexpression with NPM1c rapidly leads to an aggressive myeloproliferative disease in mice with a latency of 31.5 days. Mechanistically, we could show that FLT3-TKD is able to activate the downstream effector molecule signal transducer and activator of transcription 5 (STAT5) exclusively in the presence of mutated NPM1c. Moreover, NPM1c alters the cellular localization of FLT3-TKD from the cell surface to the endoplasmic reticulum, which might thereby lead to the aberrant STAT5 activation. Importantly, aberrant STAT5 activation occurs not only in primary murine cells but also in patients with AML with combined FLT3-TKD and NPM1c mutations. Thus, our data indicate a new mechanism, how NPM1c mislocalizes FLT3-TKD and changes its signal transduction ability.


Assuntos
Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Mutação , Proteínas Nucleares/genética , Transdução de Sinais , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/metabolismo , Substituição de Aminoácidos , Animais , Modelos Animais de Doenças , Retículo Endoplasmático/metabolismo , Duplicação Gênica , Regulação Leucêmica da Expressão Gênica , Humanos , Camundongos , Proteínas Nucleares/metabolismo , Transporte Proteico , Fator de Transcrição STAT5/metabolismo , Sequências de Repetição em Tandem
12.
Curr Opin Genet Dev ; 54: 83-87, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-31063922

RESUMO

Acute myeloid leukemia (AML) is an aggressive cancer that remains lethal to the majority of sufferers. Whilst the mainstay treatments for this condition have remained largely unchanged over the past five decades, progress in deciphering its pathogenesis has accelerated in recent years, propelled in part by advances in cancer genomics and mechanistic studies of leukemogenic mutations. Newer molecular therapies targeting aberrant biological pathways are currently under investigation with a few moving closer to clinical use. However, collectively, these new therapies are not predicted to have a major impact on clinical outcomes and the need for the identification of further therapeutic targets in AML remains critical. Recently the use of CRISPR-Cas9 systems for genome editing and their potential application in genome-wide screening has opened a new frontier for unbiased discovery of therapeutic vulnerabilities in cancer and AML was the first disease in which this technology was systematically applied. In this review we give an overview of recent advances in identifying novel therapeutic vulnerabilities of AML using CRISPR-Cas9 and discuss possible future applications of CRISPR technologies in this field.


Assuntos
Sistemas CRISPR-Cas/genética , Ensaios de Seleção de Medicamentos Antitumorais , Leucemia Mieloide Aguda/tratamento farmacológico , Edição de Genes , Genoma Humano/genética , Genômica , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Mutação/genética
13.
J Exp Med ; 216(4): 966-981, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30890554

RESUMO

Epigenetic regulators, such as EZH2, are frequently mutated in cancer, and loss-of-function EZH2 mutations are common in myeloid malignancies. We have examined the importance of cellular context for Ezh2 loss during the evolution of acute myeloid leukemia (AML), where we observed stage-specific and diametrically opposite functions for Ezh2 at the early and late stages of disease. During disease maintenance, WT Ezh2 exerts an oncogenic function that may be therapeutically targeted. In contrast, Ezh2 acts as a tumor suppressor during AML induction. Transcriptional analysis explains this apparent paradox, demonstrating that loss of Ezh2 derepresses different expression programs during disease induction and maintenance. During disease induction, Ezh2 loss derepresses a subset of bivalent promoters that resolve toward gene activation, inducing a feto-oncogenic program that includes genes such as Plag1, whose overexpression phenocopies Ezh2 loss to accelerate AML induction in mouse models. Our data highlight the importance of cellular context and disease phase for the function of Ezh2 and its potential therapeutic implications.

14.
Nat Commun ; 10(1): 1415, 2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30926791

RESUMO

B-cell lymphoma (BCL) is the most common hematologic malignancy. While sequencing studies gave insights into BCL genetics, identification of non-mutated cancer genes remains challenging. Here, we describe PiggyBac transposon tools and mouse models for recessive screening and show their application to study clonal B-cell lymphomagenesis. In a genome-wide screen, we discover BCL genes related to diverse molecular processes, including signaling, transcriptional regulation, chromatin regulation, or RNA metabolism. Cross-species analyses show the efficiency of the screen to pinpoint human cancer drivers altered by non-genetic mechanisms, including clinically relevant genes dysregulated epigenetically, transcriptionally, or post-transcriptionally in human BCL. We also describe a CRISPR/Cas9-based in vivo platform for BCL functional genomics, and validate discovered genes, such as Rfx7, a transcription factor, and Phip, a chromatin regulator, which suppress lymphomagenesis in mice. Our study gives comprehensive insights into the molecular landscapes of BCL and underlines the power of genome-scale screening to inform biology.


Assuntos
Elementos de DNA Transponíveis/genética , Testes Genéticos/métodos , Linfoma de Células B/genética , Animais , Sistemas CRISPR-Cas/genética , Células Clonais , Dosagem de Genes , Regulação Neoplásica da Expressão Gênica , Genes Neoplásicos , Genes Supressores de Tumor , Estudos de Associação Genética , Humanos , Perda de Heterozigosidade , Linfoma de Células B/patologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos B/metabolismo , Reprodutibilidade dos Testes
15.
Genome Res ; 29(4): 564-575, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30796038

RESUMO

The epigenetic regulator TET2 is frequently mutated in hematological diseases. Mutations have been shown to arise in hematopoietic stem cells early in disease development and lead to altered DNA methylation landscapes and an increased risk of hematopoietic malignancy. Here, we show by genome-wide mapping of TET2 binding sites in different cell types that TET2 localizes to regions of open chromatin and cell-type-specific enhancers. We find that deletion of Tet2 in native hematopoiesis as well as fully transformed acute myeloid leukemia (AML) results in changes in transcription factor (TF) activity within these regions, and we provide evidence that loss of TET2 leads to attenuation of chromatin binding of members of the basic helix-loop-helix (bHLH) TF family. Together, these findings demonstrate that TET2 activity shapes the local chromatin environment at enhancers to facilitate TF binding and provides an example of how epigenetic dysregulation can affect gene expression patterns and drive disease development.


Assuntos
Cromatina/metabolismo , Proteínas de Ligação a DNA/metabolismo , Elementos Facilitadores Genéticos , Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide Aguda/genética , Proteínas Proto-Oncogênicas/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Linhagem Celular , Células Cultivadas , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Leucemia Mieloide Aguda/metabolismo , Camundongos , Ligação Proteica
18.
Nat Commun ; 9(1): 5378, 2018 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-30568163

RESUMO

We recently identified the splicing kinase gene SRPK1 as a genetic vulnerability of acute myeloid leukemia (AML). Here, we show that genetic or pharmacological inhibition of SRPK1 leads to cell cycle arrest, leukemic cell differentiation and prolonged survival of mice transplanted with MLL-rearranged AML. RNA-seq analysis demonstrates that SRPK1 inhibition leads to altered isoform levels of many genes including several with established roles in leukemogenesis such as MYB, BRD4 and MED24. We focus on BRD4 as its main isoforms have distinct molecular properties and find that SRPK1 inhibition produces a significant switch from the short to the long isoform at the mRNA and protein levels. This was associated with BRD4 eviction from genomic loci involved in leukemogenesis including BCL2 and MYC. We go on to show that this switch mediates at least part of the anti-leukemic effects of SRPK1 inhibition. Our findings reveal that SRPK1 represents a plausible new therapeutic target against AML.


Assuntos
Leucemia Mieloide Aguda/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Fatores de Transcrição/metabolismo , Pontos de Checagem do Ciclo Celular , Proteínas de Ciclo Celular , Diferenciação Celular , Cromatina/metabolismo , Epigênese Genética , Células HL-60 , Hematopoese , Humanos , Células K562 , Isoformas de Proteínas/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genética , Processamento de RNA
19.
Sci Rep ; 8(1): 13537, 2018 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-30202034

RESUMO

Anaplastic meningioma is a rare and aggressive brain tumor characterised by intractable recurrences and dismal outcomes. Here, we present an integrated analysis of the whole genome, transcriptome and methylation profiles of primary and recurrent anaplastic meningioma. A key finding was the delineation of distinct molecular subgroups that were associated with diametrically opposed survival outcomes. Relative to lower grade meningiomas, anaplastic tumors harbored frequent driver mutations in SWI/SNF complex genes, which were confined to the poor prognosis subgroup. Aggressive disease was further characterised by transcriptional evidence of increased PRC2 activity, stemness and epithelial-to-mesenchymal transition. Our analyses discern biologically distinct variants of anaplastic meningioma with prognostic and therapeutic significance.


Assuntos
Regulação Neoplásica da Expressão Gênica , Neoplasias Meníngeas/genética , Meningioma/genética , Recidiva Local de Neoplasia/genética , Transcriptoma/genética , Idoso , Metilação de DNA/genética , Progressão da Doença , Feminino , Perfilação da Expressão Gênica , Genômica/métodos , Humanos , Masculino , Neoplasias Meníngeas/mortalidade , Neoplasias Meníngeas/patologia , Neoplasias Meníngeas/cirurgia , Meningioma/mortalidade , Meningioma/patologia , Meningioma/cirurgia , Pessoa de Meia-Idade , Gradação de Tumores , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/patologia , Prognóstico , Análise de Sobrevida , Sequenciamento Completo do Genoma
20.
Front Immunol ; 9: 1784, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30147686

RESUMO

A diverse B-cell receptor (BCR) repertoire is required to bind a wide range of antigens. BCRs are generated through genetic recombination and can be diversified through somatic hypermutation (SHM) or class-switch recombination (CSR). Patterns of repertoire diversity can vary substantially between different health conditions. We use isotype-resolved BCR sequencing to compare B-cell evolution and class-switch fate in healthy individuals and in patients with chronic lymphocytic leukemia (CLL). We show that the patterns of SHM and CSR in B-cells from healthy individuals are distinct from CLL. We identify distinct properties of clonal expansion that lead to the generation of antibodies of different classes in healthy, malignant, and non-malignant CLL BCR repertoires. We further demonstrate that BCR diversity is affected by relationships between antibody variable and constant regions leading to isotype-specific signatures of variable gene usage. This study provides powerful insights into the mechanisms underlying the evolution of the adaptive immune responses in health and their aberration during disease.


Assuntos
Linfócitos B/metabolismo , Rearranjo Gênico do Linfócito B , Switching de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/genética , Receptores de Antígenos de Linfócitos B/genética , Hipermutação Somática de Imunoglobulina , Linfócitos B/imunologia , Linfócitos B/patologia , Humanos , Isotipos de Imunoglobulinas/genética , Região de Junção de Imunoglobulinas/genética , Região Variável de Imunoglobulina/genética , Leucemia Linfocítica Crônica de Células B/imunologia , Leucemia Linfocítica Crônica de Células B/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/patologia , Família Multigênica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA