RESUMO
How hematopoietic stem cells (HSCs) coordinate the regulation of opposing cellular mechanisms such as self-renewal and differentiation commitment remains unclear. Here we identified the transcription factor and chromatin remodeler Satb1 as a critical regulator of HSC fate. HSCs lacking Satb1 had defective self-renewal, were less quiescent and showed accelerated lineage commitment, which resulted in progressive depletion of functional HSCs. The enhanced commitment was caused by less symmetric self-renewal and more symmetric differentiation divisions of Satb1-deficient HSCs. Satb1 simultaneously repressed sets of genes encoding molecules involved in HSC activation and cellular polarity, including Numb and Myc, which encode two key factors for the specification of stem-cell fate. Thus, Satb1 is a regulator that promotes HSC quiescence and represses lineage commitment.
Assuntos
Células-Tronco Hematopoéticas/fisiologia , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Animais , Diferenciação Celular/genética , Linhagem da Célula/genética , Polaridade Celular/genética , Sobrevivência Celular/genética , Células Cultivadas , Montagem e Desmontagem da Cromatina/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Proteínas de Ligação à Região de Interação com a Matriz/genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismoRESUMO
Neomorphic mutations in isocitrate dehydrogenase 1 (IDH1) are driver mutations in acute myeloid leukemia (AML) and other cancers. We report the development of new allosteric inhibitors of mutant IDH1. Crystallographic and biochemical results demonstrated that compounds of this chemical series bind to an allosteric site and lock the enzyme in a catalytically inactive conformation, thereby enabling inhibition of different clinically relevant IDH1 mutants. Treatment of IDH1 mutant primary AML cells uniformly led to a decrease in intracellular 2-HG, abrogation of the myeloid differentiation block and induction of granulocytic differentiation at the level of leukemic blasts and more immature stem-like cells, in vitro and in vivo. Molecularly, treatment with the inhibitors led to a reversal of the DNA cytosine hypermethylation patterns caused by mutant IDH1 in the cells of individuals with AML. Our study provides proof of concept for the molecular and biological activity of novel allosteric inhibitors for targeting different mutant forms of IDH1 in leukemia.
Assuntos
Di-Hidropiridinas/farmacologia , Inibidores Enzimáticos/farmacologia , Isocitrato Desidrogenase/antagonistas & inibidores , Leucemia Mieloide Aguda/tratamento farmacológico , Pirazóis/farmacologia , Regulação Alostérica , Sítio Alostérico , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ilhas de CpG , Cristalografia por Raios X , Citosina/química , Citosina/metabolismo , Metilação de DNA/efeitos dos fármacos , Di-Hidropiridinas/química , Di-Hidropiridinas/farmacocinética , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacocinética , Granulócitos/efeitos dos fármacos , Granulócitos/enzimologia , Granulócitos/patologia , Humanos , Isocitrato Desidrogenase/química , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Cinética , Leucemia Mieloide Aguda/enzimologia , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Masculino , Camundongos , Modelos Moleculares , Mutação , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/enzimologia , Células-Tronco Neoplásicas/patologia , Cultura Primária de Células , Ligação Proteica , Pirazóis/química , Pirazóis/farmacocinética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Acute myeloid leukemia (AML) is characterized by disruption of HSC and progenitor cell differentiation. Frequently, AML is associated with mutations in genes encoding epigenetic modifiers. We hypothesized that analysis of alterations in DNA methylation patterns during healthy HSC commitment and differentiation would yield epigenetic signatures that could be used to identify stage-specific prognostic subgroups of AML. We performed a nano HpaII-tiny-fragment-enrichment-by-ligation-mediated-PCR (nanoHELP) assay to compare genome-wide cytosine methylation profiles between highly purified human long-term HSC, short-term HSC, common myeloid progenitors, and megakaryocyte-erythrocyte progenitors. We observed that the most striking epigenetic changes occurred during the commitment of short-term HSC to common myeloid progenitors and these alterations were predominantly characterized by loss of methylation. We developed a metric of the HSC commitmentassociated methylation pattern that proved to be highly prognostic of overall survival in 3 independent large AML patient cohorts, regardless of patient treatment and epigenetic mutations. Application of the epigenetic signature metric for AML prognosis was superior to evaluation of commitment-based gene expression signatures. Together, our data define a stem cell commitmentassociated methylome that is independently prognostic of poorer overall survival in AML.
Assuntos
Diferenciação Celular , Epigênese Genética , Células-Tronco Hematopoéticas/fisiologia , Leucemia Mieloide Aguda/patologia , Metilação de DNA , Humanos , Estimativa de Kaplan-Meier , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/mortalidade , Prognóstico , Modelos de Riscos Proporcionais , TranscriptomaRESUMO
Homeobox domain-containing transcription factors are important regulators of hematopoiesis. Here, we report that increased levels of nonclustered H2.0-like homeobox (HLX) lead to loss of functional hematopoietic stem cells and formation of aberrant progenitors with unlimited serial clonogenicity and blocked differentiation. Inhibition of HLX reduces proliferation and clonogenicity of leukemia cells, overcomes the differentiation block, and leads to prolonged survival. HLX regulates a transcriptional program, including PAK1 and BTG1, that controls cellular differentiation and proliferation. HLX is overexpressed in 87% of patients with acute myeloid leukemia (AML) and independently correlates with inferior overall survival (n = 601, p = 2.3 × 10(-6)). Our study identifies HLX as a key regulator in immature hematopoietic and leukemia cells and as a prognostic marker and therapeutic target in AML.