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1.
Nat Med ; 25(12): 1839-1842, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31768065

RESUMO

Histiocytoses are clonal hematopoietic disorders frequently driven by mutations mapping to the BRAF and MEK1 and MEK2 kinases. Currently, however, the developmental origins of histiocytoses in patients are not well understood, and clinically meaningful therapeutic targets outside of BRAF and MEK are undefined. In this study, we uncovered activating mutations in CSF1R and rearrangements in RET and ALK that conferred dramatic responses to selective inhibition of RET (selpercatinib) and crizotinib, respectively, in patients with histiocytosis.


Assuntos
Quinase do Linfoma Anaplásico/genética , Histiocitose/genética , Proteínas Proto-Oncogênicas c-ret/genética , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Adolescente , Adulto , Aminopiridinas/farmacologia , Benzotiazóis/farmacologia , Criança , Pré-Escolar , Feminino , Genoma Humano , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/patologia , Histiocitose/tratamento farmacológico , Histiocitose/patologia , Humanos , Lactente , Masculino , Mutação , Ácidos Picolínicos/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/farmacologia , Piridinas/farmacologia , Pirróis/farmacologia , Receptores Proteína Tirosina Quinases/genética , Gêmeos Monozigóticos , Sequenciamento Completo do Exoma , Adulto Jovem
2.
Nature ; 574(7777): 273-277, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31578525

RESUMO

Transcription and pre-mRNA splicing are key steps in the control of gene expression and mutations in genes regulating each of these processes are common in leukaemia1,2. Despite the frequent overlap of mutations affecting epigenetic regulation and splicing in leukaemia, how these processes influence one another to promote leukaemogenesis is not understood and, to our knowledge, there is no functional evidence that mutations in RNA splicing factors initiate leukaemia. Here, through analyses of transcriptomes from 982 patients with acute myeloid leukaemia, we identified frequent overlap of mutations in IDH2 and SRSF2 that together promote leukaemogenesis through coordinated effects on the epigenome and RNA splicing. Whereas mutations in either IDH2 or SRSF2 imparted distinct splicing changes, co-expression of mutant IDH2 altered the splicing effects of mutant SRSF2 and resulted in more profound splicing changes than either mutation alone. Consistent with this, co-expression of mutant IDH2 and SRSF2 resulted in lethal myelodysplasia with proliferative features in vivo and enhanced self-renewal in a manner not observed with either mutation alone. IDH2 and SRSF2 double-mutant cells exhibited aberrant splicing and reduced expression of INTS3, a member of the integrator complex3, concordant with increased stalling of RNA polymerase II (RNAPII). Aberrant INTS3 splicing contributed to leukaemogenesis in concert with mutant IDH2 and was dependent on mutant SRSF2 binding to cis elements in INTS3 mRNA and increased DNA methylation of INTS3. These data identify a pathogenic crosstalk between altered epigenetic state and splicing in a subset of leukaemias, provide functional evidence that mutations in splicing factors drive myeloid malignancy development, and identify spliceosomal changes as a mediator of IDH2-mutant leukaemogenesis.


Assuntos
Processamento Alternativo/genética , Carcinogênese/genética , Epigênese Genética , Leucemia Mieloide Aguda/genética , Animais , Linhagem Celular Tumoral , Proliferação de Células , Metilação de DNA , Proteínas de Ligação a DNA/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Isocitrato Desidrogenase/genética , Masculino , Mutação/genética , RNA Polimerase II/metabolismo , Fatores de Processamento de Serina-Arginina/genética , Transcriptoma
4.
J Hematol Oncol ; 12(1): 85, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31439003

RESUMO

We tested whether a single nucleotide polymorphism (SNP) that affects splicing of CD33 predicted response to treatment in adults with acute myeloid leukemia (AML) who received the novel CD33 antibody-drug conjugate SGN-CD33A. This genotype, for the CD33 splice site SNP rs12459419, was not associated with clinical response (30% CR/CRi in both groups), event-free survival, or overall survival.

5.
Nature ; 571(7765): 355-360, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31270458

RESUMO

Defining the transcriptomic identity of malignant cells is challenging in the absence of surface markers that distinguish cancer clones from one another, or from admixed non-neoplastic cells. To address this challenge, here we developed Genotyping of Transcriptomes (GoT), a method to integrate genotyping with high-throughput droplet-based single-cell RNA sequencing. We apply GoT to profile 38,290 CD34+ cells from patients with CALR-mutated myeloproliferative neoplasms to study how somatic mutations corrupt the complex process of human haematopoiesis. High-resolution mapping of malignant versus normal haematopoietic progenitors revealed an increasing fitness advantage with myeloid differentiation of cells with mutated CALR. We identified the unfolded protein response as a predominant outcome of CALR mutations, with a considerable dependency on cell identity, as well as upregulation of the NF-κB pathway specifically in uncommitted stem cells. We further extended the GoT toolkit to genotype multiple targets and loci that are distant from transcript ends. Together, these findings reveal that the transcriptional output of somatic mutations in myeloproliferative neoplasms is dependent on the native cell identity.


Assuntos
Genótipo , Mutação , Transtornos Mieloproliferativos/genética , Transtornos Mieloproliferativos/patologia , Neoplasias/genética , Neoplasias/patologia , Transcriptoma/genética , Animais , Antígenos CD34/metabolismo , Calreticulina/genética , Linhagem Celular , Proliferação de Células , Células Clonais/classificação , Células Clonais/metabolismo , Células Clonais/patologia , Endorribonucleases/metabolismo , Hematopoese/genética , Células-Tronco Hematopoéticas/classificação , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/patologia , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Camundongos , Modelos Moleculares , Transtornos Mieloproliferativos/classificação , NF-kappa B/metabolismo , Neoplasias/classificação , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Mielofibrose Primária/genética , Mielofibrose Primária/patologia , Proteínas Serina-Treonina Quinases/metabolismo , Análise de Sequência de RNA/métodos , Análise de Célula Única/métodos , Resposta a Proteínas não Dobradas/genética
6.
Cancer Discov ; 9(10): 1452-1467, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31285298

RESUMO

Altered expression of XPO1, the main nuclear export receptor in eukaryotic cells, has been observed in cancer, and XPO1 has been a focus of anticancer drug development. However, mechanistic evidence for cancer-specific alterations in XPO1 function is lacking. Here, genomic analysis of 42,793 cancers identified recurrent and previously unrecognized mutational hotspots in XPO1. XPO1 mutations exhibited striking lineage specificity, with enrichment in a variety of B-cell malignancies, and introduction of single amino acid substitutions in XPO1 initiated clonal, B-cell malignancy in vivo. Proteomic characterization identified that mutant XPO1 altered the nucleocytoplasmic distribution of hundreds of proteins in a sequence-specific manner that promoted oncogenesis. XPO1 mutations preferentially sensitized cells to inhibitors of nuclear export, providing a biomarker of response to this family of drugs. These data reveal a new class of oncogenic alteration based on change-of-function mutations in nuclear export signal recognition and identify therapeutic targets based on altered nucleocytoplasmic trafficking. SIGNIFICANCE: Here, we identify that heterozygous mutations in the main nuclear exporter in eukaryotic cells, XPO1, are positively selected in cancer and promote the initiation of clonal B-cell malignancies. XPO1 mutations alter nuclear export signal recognition in a sequence-specific manner and sensitize cells to compounds in clinical development inhibiting XPO1 function.This article is highlighted in the In This Issue feature, p. 1325.

7.
Nature ; 569(7757): 576-580, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31092926

RESUMO

Genetic and epigenetic intra-tumoral heterogeneity cooperate to shape the evolutionary course of cancer1. Chronic lymphocytic leukaemia (CLL) is a highly informative model for cancer evolution as it undergoes substantial genetic diversification and evolution after therapy2,3. The CLL epigenome is also an important disease-defining feature4,5, and growing populations of cells in CLL diversify by stochastic changes in DNA methylation known as epimutations6. However, previous studies using bulk sequencing methods to analyse the patterns of DNA methylation were unable to determine whether epimutations affect CLL populations homogeneously. Here, to measure the epimutation rate at single-cell resolution, we applied multiplexed single-cell reduced-representation bisulfite sequencing to B cells from healthy donors and patients with CLL. We observed that the common clonal origin of CLL results in a consistently increased epimutation rate, with low variability in the cell-to-cell epimutation rate. By contrast, variable epimutation rates across healthy B cells reflect diverse evolutionary ages across the trajectory of B cell differentiation, consistent with epimutations serving as a molecular clock. Heritable epimutation information allowed us to reconstruct lineages at high-resolution with single-cell data, and to apply this directly to patient samples. The CLL lineage tree shape revealed earlier branching and longer branch lengths than in normal B cells, reflecting rapid drift after the initial malignant transformation and a greater proliferative history. Integration of single-cell bisulfite sequencing analysis with single-cell transcriptomes and genotyping confirmed that genetic subclones mapped to distinct clades, as inferred solely on the basis of epimutation information. Finally, to examine potential lineage biases during therapy, we profiled serial samples during ibrutinib-associated lymphocytosis, and identified clades of cells that were preferentially expelled from the lymph node after treatment, marked by distinct transcriptional profiles. The single-cell integration of genetic, epigenetic and transcriptional information thus charts the lineage history of CLL and its evolution with therapy.

8.
Nat Commun ; 10(1): 1874, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31015400

RESUMO

Cancer evolution is fueled by epigenetic as well as genetic diversity. In chronic lymphocytic leukemia (CLL), intra-tumoral DNA methylation (DNAme) heterogeneity empowers evolution. Here, to comprehensively study the epigenetic dimension of cancer evolution, we integrate DNAme analysis with histone modification mapping and single cell analyses of RNA expression and DNAme in 22 primary CLL and 13 healthy donor B lymphocyte samples. Our data reveal corrupted coherence across different layers of the CLL epigenome. This manifests in decreased mutual information across epigenetic modifications and gene expression attributed to cell-to-cell heterogeneity. Disrupted epigenetic-transcriptional coordination in CLL is also reflected in the dysregulation of the transcriptional output as a function of the combinatorial chromatin states, including incomplete Polycomb-mediated gene silencing. Notably, we observe unexpected co-mapping of typically mutually exclusive activating and repressing histone modifications, suggestive of intra-tumoral epigenetic diversity. Thus, CLL epigenetic diversification leads to decreased coordination across layers of epigenetic information, likely reflecting an admixture of cells with diverging cellular identities.


Assuntos
Linfócitos B/metabolismo , Cromatina/metabolismo , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Leucemia Linfocítica Crônica de Células B/genética , Metilação de DNA , Evolução Molecular , Inativação Gênica , Genes de Cadeia Pesada de Imunoglobulina/genética , Voluntários Saudáveis , Código das Histonas/genética , Histonas/genética , Histonas/metabolismo , Humanos , Leucemia Linfocítica Crônica de Células B/sangue , Proteínas do Grupo Polycomb/genética , Proteínas do Grupo Polycomb/metabolismo , Regiões Promotoras Genéticas/genética , Análise de Sequência de RNA , Análise de Célula Única/métodos , Sequenciamento Completo do Exoma
9.
Blood Adv ; 3(7): 1033-1038, 2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30940638

RESUMO

The Follicular Lymphoma (FL) International Prognostic Index (FLIPI) and FLIPI-2 are well-described clinical risk models. Age >60 years at diagnosis is a risk factor in both scores. Recently, we showed that older age is not associated with higher risk of disease progression or inferior treatment efficacy. Instead, shorter survival of older patients results mainly from an increased risk of nonrelapse deaths. This questions the value of age as a meaningful component of scores intended to predict disease-specific survival. The newly proposed PRIMA-prognostic index (PRIMA-PI) only includes ß2-microglobulin levels and bone marrow infiltration as risk factors. Here, we independently validate the PRIMA-PI in a clinical trial cohort of 475 patients with advanced FL who uniformly received cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, prednisone, and rituximab (R-CHOP) as frontline therapy. The PRIMA-PI separated 3 similar sized risk cohorts with 5-year progression-free survival (PFS) rates of 74%, 59%, and 39%, respectively (P < .0001). Furthermore, we compare the PRIMA-PI with the FLIPI and FLIPI-2. We demonstrate that the PRIMA-PI has the highest specificity to identify high-risk patients (80% for 5-year PFS) because of its superior risk stratification in patients >60 years (73% vs 33% [FLIPI] and 47% [FLIPI-2] for 5-year PFS). Thus, the PRIMA-PI is a promising clinical tool to stringently identify patients at highest risk of poor outcome after frontline R-CHOP for advanced FL, and is particularly useful in patients with older age. Further validation in non-R-CHOP treated cohorts is needed.

10.
Cancer Cell ; 35(3): 369-384.e7, 2019 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-30799057

RESUMO

RNA-binding proteins (RBPs) are essential modulators of transcription and translation frequently dysregulated in cancer. We systematically interrogated RBP dependencies in human cancers using a comprehensive CRISPR/Cas9 domain-focused screen targeting RNA-binding domains of 490 classical RBPs. This uncovered a network of physically interacting RBPs upregulated in acute myeloid leukemia (AML) and crucial for maintaining RNA splicing and AML survival. Genetic or pharmacologic targeting of one key member of this network, RBM39, repressed cassette exon inclusion and promoted intron retention within mRNAs encoding HOXA9 targets as well as in other RBPs preferentially required in AML. The effects of RBM39 loss on splicing further resulted in preferential lethality of spliceosomal mutant AML, providing a strategy for treatment of AML bearing RBP splicing mutations.


Assuntos
Redes Reguladoras de Genes , Marcação de Genes/métodos , Leucemia Mieloide Aguda/patologia , Proteômica/métodos , Proteínas de Ligação a RNA/genética , Regulação para Cima , Processamento Alternativo , Animais , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Feminino , Regulação Neoplásica da Expressão Gênica , Células HL-60 , Proteínas de Homeodomínio/genética , Humanos , Células Jurkat , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Masculino , Camundongos , Transplante de Neoplasias , Prognóstico , Proteínas de Ligação a RNA/metabolismo , Análise de Sequência de RNA/métodos , Análise de Sobrevida
11.
Cancer Cell ; 34(2): 225-241.e8, 2018 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-30107174

RESUMO

Mutations affecting RNA splicing factors are the most common genetic alterations in myelodysplastic syndrome (MDS) patients and occur in a mutually exclusive manner. The basis for the mutual exclusivity of these mutations and how they contribute to MDS is not well understood. Here we report that although different spliceosome gene mutations impart distinct effects on splicing, they are negatively selected for when co-expressed due to aberrant splicing and downregulation of regulators of hematopoietic stem cell survival and quiescence. In addition to this synthetic lethal interaction, mutations in the splicing factors SF3B1 and SRSF2 share convergent effects on aberrant splicing of mRNAs that promote nuclear factor κB signaling. These data identify shared consequences of splicing-factor mutations and the basis for their mutual exclusivity.


Assuntos
Mutação , Neoplasias/genética , Spliceossomos , Animais , Caspase 8/genética , Feminino , Hematopoese , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NF-kappa B/fisiologia , Fosfoproteínas/genética , Fatores de Processamento de RNA/genética , Fatores de Processamento de Serina-Arginina/genética
12.
Blood ; 132(16): 1695-1702, 2018 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-30126979

RESUMO

Duodenal-type follicular lymphoma (DTFL) is a rare and highly indolent follicular lymphoma (FL) variant. It is morphologically and immunophenotypically indistinguishable from typical FL, characterized by restricted involvement of intestinal mucosa, and lacks extraintestinal manifestations. The molecular determinants of this distinct clinical behavior are largely unknown. Thirty-eight diagnostic biopsies from patients with DTFL were evaluated. The 10-year overall survival rate was 100% in clinically evaluable patients (n = 19). We compared the targeted mutation profile of DTFL (n = 31), limited-stage typical FL (LSTFL; n = 17), and advanced-stage typical FL (ASTFL; n = 241). The mutation frequencies of recurrently mutated genes, including CREBBP, TNFRSF14/HVEM, and EZH2 were not significantly different. However, KMT2D was less commonly mutated in DTFL (52%) and LSTFL (24%) as compared with ASTFL (79%). In ASTFL, 41% of KMT2D-mutated cases harbored multiple mutations in KMT2D, as compared with only 12% in LSTFL (P = .019) and 0% in DTFL (P < .0001). Whole exome and targeted sequencing of DTFL revealed high mutation frequencies of EEF1A1 (35%) and HVCN1 (22%). We compared the immune microenvironment gene expression signatures of DTFL (n = 8) and LSTFL (n = 7). DTFL clearly separated from LSTFL by unsupervised, hierarchical clustering of 147 chemokines and cytokines and was enriched for a chronic inflammation signature. In conclusion, the mutational landscape of DTFL is highly related to typical FL. The lower frequency of multiple mutations in KMT2D in DTFL and LSTFL indicates an increasing selection pressure for complete KMT2D loss in ASTFL pathogenesis. The highly dissimilar immune microenvironment of DTFL suggests a central role in the biology of this disease.


Assuntos
Biomarcadores Tumorais/genética , Proteínas de Ligação a DNA/genética , Neoplasias Duodenais/imunologia , Inflamação/imunologia , Linfoma Folicular/imunologia , Mutação , Proteínas de Neoplasias/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Citocinas/metabolismo , Análise Mutacional de DNA , Neoplasias Duodenais/genética , Neoplasias Duodenais/patologia , Exoma , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Humanos , Inflamação/genética , Inflamação/patologia , Linfoma Folicular/genética , Linfoma Folicular/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Taxa de Sobrevida , Microambiente Tumoral , Adulto Jovem
13.
Oncogene ; 37(34): 4692-4710, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29755131

RESUMO

Estrogen receptor alpha (ERα) is a ligand-activated nuclear receptor that directs proliferation and differentiation in selected cancer cell types including mammary-derived carcinomas. These master-regulatory functions of ERα require trans-acting elements such as the pioneer factor FOXA1 to establish a genomic landscape conducive to ERα control. Here, we identify the H3K4 methyltransferase KMT2C as necessary for hormone-driven ERα activity and breast cancer proliferation. KMT2C knockdown suppresses estrogen-dependent gene expression and causes H3K4me1 and H3K27ac loss selectively at ERα enhancers. Correspondingly, KMT2C loss impairs estrogen-driven breast cancer proliferation but has no effect on ER- breast cells. Whereas KMT2C loss disrupts estrogen-driven proliferation, it conversely promotes tumor outgrowth under hormone-depleted conditions. In accordance, KMT2C is one of the most frequently mutated genes in ER-positive breast cancer with KMT2C deletion correlating with significantly shorter progression-free survival on anti-estrogen therapy. From a therapeutic standpoint, KMT2C-depleted cells that develop hormone-independence retain their dependence on ERα, displaying ongoing sensitivity to ERα antagonists. We conclude that KMT2C is a key regulator of ERα activity whose loss uncouples breast cancer proliferation from hormone abundance.


Assuntos
Neoplasias da Mama/metabolismo , Proteínas de Ligação a DNA/metabolismo , Receptor alfa de Estrogênio/metabolismo , Estrogênios/metabolismo , Proteínas de Neoplasias/metabolismo , Animais , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Células HEK293 , Fator 3-alfa Nuclear de Hepatócito/metabolismo , Humanos , Células MCF-7 , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Intervalo Livre de Progressão , Transdução de Sinais/fisiologia
14.
J Exp Med ; 215(6): 1729-1747, 2018 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-29643185

RESUMO

Additional sex combs like 1 (ASXL1) is frequently mutated in myeloid malignancies and clonal hematopoiesis of indeterminate potential (CHIP). Although loss of ASXL1 promotes hematopoietic transformation, there is growing evidence that ASXL1 mutations might confer an alteration of function. In this study, we identify that physiological expression of a C-terminal truncated Asxl1 mutant in vivo using conditional knock-in (KI) results in myeloid skewing, age-dependent anemia, thrombocytosis, and morphological dysplasia. Although expression of mutant Asxl1 altered the functions of hematopoietic stem cells (HSCs), it maintained their survival in competitive transplantation assays and increased susceptibility to leukemic transformation by co-occurring RUNX1 mutation or viral insertional mutagenesis. KI mice displayed substantial reductions in H3K4me3 and H2AK119Ub without significant reductions in H3K27me3, distinct from the effects of Asxl1 loss. Chromatin immunoprecipitation followed by next-generation sequencing analysis demonstrated opposing effects of wild-type and mutant Asxl1 on H3K4me3. These findings reveal that ASXL1 mutations confer HSCs with an altered epigenome and increase susceptibility for leukemic transformation, presenting a novel model for CHIP.


Assuntos
Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Hematopoese , Leucemia/genética , Leucemia/patologia , Mutação/genética , Proteínas Repressoras/genética , Adulto , Animais , Sequência de Bases , Epigênese Genética , Regulação Leucêmica da Expressão Gênica , Técnicas de Introdução de Genes , Genoma Humano , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/metabolismo , Histonas/metabolismo , Humanos , Leucemia Mieloide Aguda/patologia , Camundongos , Mutagênese/genética , Síndromes Mielodisplásicas/patologia , Fenótipo , Ligação Proteica , Proteínas Repressoras/metabolismo , Transcrição Genética
16.
Nature ; 549(7672): 389-393, 2017 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-28854169

RESUMO

The pathophysiology of neurodegenerative diseases is poorly understood and there are few therapeutic options. Neurodegenerative diseases are characterized by progressive neuronal dysfunction and loss, and chronic glial activation. Whether microglial activation, which is generally viewed as a secondary process, is harmful or protective in neurodegeneration remains unclear. Late-onset neurodegenerative disease observed in patients with histiocytoses, which are clonal myeloid diseases associated with somatic mutations in the RAS-MEK-ERK pathway such as BRAF(V600E), suggests a possible role of somatic mutations in myeloid cells in neurodegeneration. Yet the expression of BRAF(V600E) in the haematopoietic stem cell lineage causes leukaemic and tumoural diseases but not neurodegenerative disease. Microglia belong to a lineage of adult tissue-resident myeloid cells that develop during organogenesis from yolk-sac erythro-myeloid progenitors (EMPs) distinct from haematopoietic stem cells. We therefore hypothesized that a somatic BRAF(V600E) mutation in the EMP lineage may cause neurodegeneration. Here we show that mosaic expression of BRAF(V600E) in mouse EMPs results in clonal expansion of tissue-resident macrophages and a severe late-onset neurodegenerative disorder. This is associated with accumulation of ERK-activated amoeboid microglia in mice, and is also observed in human patients with histiocytoses. In the mouse model, neurobehavioural signs, astrogliosis, deposition of amyloid precursor protein, synaptic loss and neuronal death were driven by ERK-activated microglia and were preventable by BRAF inhibition. These results identify the fetal precursors of tissue-resident macrophages as a potential cell-of-origin for histiocytoses and demonstrate that a somatic mutation in the EMP lineage in mice can drive late-onset neurodegeneration. Moreover, these data identify activation of the MAP kinase pathway in microglia as a cause of neurodegeneration and this offers opportunities for therapeutic intervention aimed at the prevention of neuronal death in neurodegenerative diseases.


Assuntos
Células Precursoras Eritroides/patologia , Sistema de Sinalização das MAP Quinases , Mutação , Células Progenitoras Mieloides/patologia , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Proteínas Proto-Oncogênicas B-raf/genética , Animais , Células Clonais/enzimologia , Células Clonais/metabolismo , Células Clonais/patologia , Modelos Animais de Doenças , Células Precursoras Eritroides/enzimologia , Células Precursoras Eritroides/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Histiocitose/enzimologia , Histiocitose/genética , Histiocitose/metabolismo , Histiocitose/patologia , Humanos , Macrófagos/enzimologia , Macrófagos/metabolismo , Macrófagos/patologia , Masculino , Camundongos , Microglia/enzimologia , Microglia/metabolismo , Microglia/patologia , Mosaicismo , Células Progenitoras Mieloides/enzimologia , Células Progenitoras Mieloides/metabolismo , Doenças Neurodegenerativas/enzimologia , Doenças Neurodegenerativas/metabolismo , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/metabolismo
17.
Cancer Discov ; 7(9): 1018-1029, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28619981

RESUMO

Bruton tyrosine kinase (BTK) links the B-cell antigen receptor (BCR) and Toll-like receptors with NF-κB. The role of BTK in primary central nervous system (CNS) lymphoma (PCNSL) is unknown. We performed a phase I clinical trial with ibrutinib, the first-in-class BTK inhibitor, for patients with relapsed or refractory CNS lymphoma. Clinical responses to ibrutinib occurred in 10 of 13 (77%) patients with PCNSL, including five complete responses. The only PCNSL with complete ibrutinib resistance harbored a mutation within the coiled-coil domain of CARD11, a known ibrutinib resistance mechanism. Incomplete tumor responses were associated with mutations in the B-cell antigen receptor-associated protein CD79B. CD79B-mutant PCNSLs showed enrichment of mammalian target of rapamycin (mTOR)-related gene sets and increased staining with PI3K/mTOR activation markers. Inhibition of the PI3K isoforms p110α/p110δ or mTOR synergized with ibrutinib to induce cell death in CD79B-mutant PCNSL cells.Significance: Ibrutinib has substantial activity in patients with relapsed or refractory B-cell lymphoma of the CNS. Response rates in PCNSL were considerably higher than reported for diffuse large B-cell lymphoma outside the CNS, suggesting a divergent molecular pathogenesis. Combined inhibition of BTK and PI3K/mTOR may augment the ibrutinib response in CD79B-mutant human PCNSLs. Cancer Discov; 7(9); 1018-29. ©2017 AACR.See related commentary by Lakshmanan and Byrd, p. 940This article is highlighted in the In This Issue feature, p. 920.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Linfoma de Células B/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Adulto , Tirosina Quinase da Agamaglobulinemia , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Proteínas Adaptadoras de Sinalização CARD/genética , Neoplasias do Sistema Nervoso Central/sangue , Neoplasias do Sistema Nervoso Central/líquido cefalorraquidiano , Neoplasias do Sistema Nervoso Central/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Guanilato Ciclase/genética , Humanos , Linfoma de Células B/sangue , Linfoma de Células B/líquido cefalorraquidiano , Linfoma de Células B/metabolismo , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Mutação , Inibidores de Proteínas Quinases/efeitos adversos , Inibidores de Proteínas Quinases/farmacocinética , Proteínas Tirosina Quinases/antagonistas & inibidores , Pirazóis/efeitos adversos , Pirazóis/farmacocinética , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinética , Resultado do Tratamento , Adulto Jovem
18.
Nat Commun ; 8: 15429, 2017 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-28516957

RESUMO

Additional sex combs-like (ASXL) proteins are mammalian homologues of additional sex combs (Asx), a regulator of trithorax and polycomb function in Drosophila. While there has been great interest in ASXL1 due to its frequent mutation in leukemia, little is known about its paralog ASXL2, which is frequently mutated in acute myeloid leukemia patients bearing the RUNX1-RUNX1T1 (AML1-ETO) fusion. Here we report that ASXL2 is required for normal haematopoiesis with distinct, non-overlapping effects from ASXL1 and acts as a haploinsufficient tumour suppressor. While Asxl2 was required for normal haematopoietic stem cell self-renewal, Asxl2 loss promoted AML1-ETO leukemogenesis. Moreover, ASXL2 target genes strongly overlapped with those of RUNX1 and AML1-ETO and ASXL2 loss was associated with increased chromatin accessibility at putative enhancers of key leukemogenic loci. These data reveal that Asxl2 is a critical regulator of haematopoiesis and mediates transcriptional effects that promote leukemogenesis driven by AML1-ETO.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide Aguda/genética , Proteínas de Fusão Oncogênica/genética , Proteínas Repressoras/genética , Animais , Transplante de Medula Óssea , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Modelos Animais de Doenças , Haploinsuficiência , Hematopoese/genética , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Integrases/genética , Integrases/metabolismo , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Knockout , Proteínas de Resistência a Myxovirus/genética , Proteínas de Resistência a Myxovirus/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Proteínas Repressoras/deficiência , Transdução de Sinais , Análise de Sobrevida
20.
Nat Med ; 22(6): 672-8, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27135740

RESUMO

Mutations in genes encoding splicing factors (which we refer to as spliceosomal genes) are commonly found in patients with myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). These mutations recurrently affect specific amino acid residues, leading to perturbed normal splice site and exon recognition. Spliceosomal gene mutations are always heterozygous and rarely occur together with one another, suggesting that cells may tolerate only a partial deviation from normal splicing activity. To test this hypothesis, we engineered mice to express a mutated allele of serine/arginine-rich splicing factor 2 (Srsf2(P95H))-which commonly occurs in individuals with MDS and AML-in an inducible, hemizygous manner in hematopoietic cells. These mice rapidly succumbed to fatal bone marrow failure, demonstrating that Srsf2-mutated cells depend on the wild-type Srsf2 allele for survival. In the context of leukemia, treatment with the spliceosome inhibitor E7107 (refs. 7,8) resulted in substantial reductions in leukemic burden, specifically in isogenic mouse leukemias and patient-derived xenograft AMLs carrying spliceosomal mutations. Whereas E7107 treatment of mice resulted in widespread intron retention and cassette exon skipping in leukemic cells regardless of Srsf2 genotype, the magnitude of splicing inhibition following E7107 treatment was greater in Srsf2-mutated than in Srsf2-wild-type leukemia, consistent with the differential effect of E7107 on survival. Collectively, these data provide genetic and pharmacologic evidence that leukemias with spliceosomal gene mutations are preferentially susceptible to additional splicing perturbations in vivo as compared to leukemias without such mutations. Modulation of spliceosome function may thus provide a new therapeutic avenue in genetically defined subsets of individuals with MDS or AML.


Assuntos
Leucemia Mieloide Aguda/genética , Síndromes Mielodisplásicas/genética , Fatores de Processamento de Serina-Arginina/genética , Spliceossomos/genética , Anemia Aplástica/genética , Animais , Doenças da Medula Óssea/genética , Transplante de Medula Óssea , Catálise , Linhagem Celular Tumoral , Compostos de Epóxi/farmacologia , Citometria de Fluxo , Técnicas de Introdução de Genes , Hemizigoto , Hemoglobinúria Paroxística/genética , Humanos , Macrolídeos/farmacologia , Camundongos , Camundongos Knockout , Mutação , Transplante de Neoplasias , Processamento de RNA/efeitos dos fármacos , Processamento de RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
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