RESUMEN
Design of small molecules that disrupt protein-protein interactions, including the interaction of RAS proteins and their effectors, may provide chemical probes and therapeutic agents. We describe here the synthesis and testing of potential small-molecule pan-RAS ligands, which were designed to interact with adjacent sites on the surface of oncogenic KRAS. One compound, termed 3144, was found to bind to RAS proteins using microscale thermophoresis, nuclear magnetic resonance spectroscopy, and isothermal titration calorimetry and to exhibit lethality in cells partially dependent on expression of RAS proteins. This compound was metabolically stable in liver microsomes and displayed anti-tumor activity in xenograft mouse cancer models. These findings suggest that pan-RAS inhibition may be an effective therapeutic strategy for some cancers and that structure-based design of small molecules targeting multiple adjacent sites to create multivalent inhibitors may be effective for some proteins.
Asunto(s)
Antineoplásicos/farmacología , Terapia Molecular Dirigida , Proteínas Proto-Oncogénicas p21(ras)/antagonistas & inhibidores , Proteínas Proto-Oncogénicas p21(ras)/química , Animales , Antineoplásicos/química , Calorimetría , Línea Celular , Fibroblastos/metabolismo , Xenoinjertos , Humanos , Ratones , Trasplante de Neoplasias , Neoplasias/tratamiento farmacológico , Neoplasias Pancreáticas/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras , Transducción de Señal , Bibliotecas de Moléculas PequeñasRESUMEN
Sequencing efforts led to the identification of somatic mutations that could affect the self-renewal and differentiation of cancer-initiating cells. One such recurrent mutation targets the binding pocket of the ubiquitin ligase Fbxw7. Missense FBXW7 mutations are prevalent in various tumors, including T cell acute lymphoblastic leukemia (T-ALL). To study the effects of such lesions, we generated animals carrying regulatable Fbxw7 mutant alleles. Here, we show that these mutations specifically bolster cancer-initiating cell activity in collaboration with Notch1 oncogenes but spare normal hematopoietic stem cell function. We were also able to show that FBXW7 mutations specifically affect the ubiquitylation and half-life of c-Myc protein, a key T-ALL oncogene. Using animals carrying c-Myc fusion alleles, we connected Fbxw7 function to c-Myc abundance and correlated c-Myc expression to leukemia-initiating activity. Finally, we demonstrated that small-molecule-mediated suppression of MYC activity leads to T-ALL remission, suggesting an effective therapeutic strategy.
Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteínas F-Box/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Proteínas de Ciclo Celular/genética , Modelos Animales de Enfermedad , Proteínas F-Box/genética , Proteína 7 que Contiene Repeticiones F-Box-WD , Células Madre Hematopoyéticas/metabolismo , Humanos , Ratones , Ratones Noqueados , Mutación Missense , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Proteínas Proto-Oncogénicas c-myc/antagonistas & inhibidores , Receptor Notch1/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Ubiquitina-Proteína Ligasas/genética , UbiquitinaciónRESUMEN
Clonal haematopoiesis involves the expansion of certain blood cell lineages and has been associated with ageing and adverse health outcomes1-5. Here we use exome sequence data on 628,388 individuals to identify 40,208 carriers of clonal haematopoiesis of indeterminate potential (CHIP). Using genome-wide and exome-wide association analyses, we identify 24 loci (21 of which are novel) where germline genetic variation influences predisposition to CHIP, including missense variants in the lymphocytic antigen coding gene LY75, which are associated with reduced incidence of CHIP. We also identify novel rare variant associations with clonal haematopoiesis and telomere length. Analysis of 5,041 health traits from the UK Biobank (UKB) found relationships between CHIP and severe COVID-19 outcomes, cardiovascular disease, haematologic traits, malignancy, smoking, obesity, infection and all-cause mortality. Longitudinal and Mendelian randomization analyses revealed that CHIP is associated with solid cancers, including non-melanoma skin cancer and lung cancer, and that CHIP linked to DNMT3A is associated with the subsequent development of myeloid but not lymphoid leukaemias. Additionally, contrary to previous findings from the initial 50,000 UKB exomes6, our results in the full sample do not support a role for IL-6 inhibition in reducing the risk of cardiovascular disease among CHIP carriers. Our findings demonstrate that CHIP represents a complex set of heterogeneous phenotypes with shared and unique germline genetic causes and varied clinical implications.
Asunto(s)
COVID-19 , Enfermedades Cardiovasculares , Humanos , Hematopoyesis Clonal/genética , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/genéticaRESUMEN
Leukemia cell proliferation requires up-regulation and rewiring of metabolic pathways to feed anabolic cell growth. Oncogenic drivers directly and indirectly regulate metabolic pathways, and aberrant metabolism is central not only for leukemia proliferation and survival, but also mediates oncogene addiction with significant implications for the development of targeted therapies. This review explores leukemia metabolic circuitries feeding anabolism, redox potential, and energy required for tumor propagation with an emphasis on emerging therapeutic opportunities.
Asunto(s)
Leucemia/metabolismo , Redes y Vías Metabólicas , Proliferación Celular , Humanos , Leucemia/fisiopatología , Oxidación-ReducciónRESUMEN
NOTCH1 is a well-established lineage specifier for T cells and among the most frequently mutated genes throughout all subclasses of T cell acute lymphoblastic leukemia (T-ALL). How oncogenic NOTCH1 signaling launches a leukemia-prone chromatin landscape during T-ALL initiation is unknown. Here we demonstrate an essential role for the high-mobility-group transcription factor Tcf1 in orchestrating chromatin accessibility and topology, allowing aberrant Notch1 signaling to convey its oncogenic function. Although essential, Tcf1 is not sufficient to initiate leukemia. The formation of a leukemia-prone epigenetic landscape at the distal Notch1-regulated Myc enhancer, which is fundamental to this disease, is Tcf1-dependent and occurs within the earliest progenitor stage even before cells adopt a T lymphocyte or leukemic fate. Moreover, we discovered a unique evolutionarily conserved Tcf1-regulated enhancer element in the distal Myc-enhancer, which is important for the transition of preleukemic cells to full-blown disease.
Asunto(s)
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Carcinogénesis/genética , Línea Celular Tumoral , Cromatina/genética , Humanos , Oncogenes , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Receptor Notch1/genéticaRESUMEN
Mixed-phenotype acute leukemia is a rare subtype of leukemia in which both myeloid and lymphoid markers are co-expressed on the same malignant cells. The pathogenesis is largely unknown, and the treatment is challenging. We previously reported the specific association of the recurrent t(8;12)(q13;p13) chromosomal translocation that creates the ETV6-NCOA2 fusion with T/myeloid leukemias. Here we report that ETV6-NCOA2 initiates T/myeloid leukemia in preclinical models; ectopic expression of ETV6-NCOA2 in mouse bone marrow hematopoietic progenitors induced T/myeloid lymphoma accompanied by spontaneous Notch1-activating mutations. Similarly, cotransduction of human cord blood CD34+ progenitors with ETV6-NCOA2 and a nontransforming NOTCH1 mutant induced T/myeloid leukemia in immunodeficient mice; the immunophenotype and gene expression pattern were similar to those of patient-derived ETV6-NCOA2 leukemias. Mechanistically, we show that ETV6-NCOA2 forms a transcriptional complex with ETV6 and the histone acetyltransferase p300, leading to derepression of ETV6 target genes. The expression of ETV6-NCOA2 in human and mouse nonthymic hematopoietic progenitor cells induces transcriptional dysregulation, which activates a lymphoid program while failing to repress the expression of myeloid genes such as CSF1 and MEF2C. The ETV6-NCOA2 induced arrest at an early immature T-cell developmental stage. The additional acquisition of activating NOTCH1 mutations transforms the early immature ETV6-NCOA2 cells into T/myeloid leukemias. Here, we describe the first preclinical model to depict the initiation of T/myeloid leukemia by a specific somatic genetic aberration.
Asunto(s)
Regulación Leucémica de la Expresión Génica , Células Madre Hematopoyéticas/metabolismo , Leucemia Mieloide/genética , Coactivador 2 del Receptor Nuclear/genética , Proteínas de Fusión Oncogénica/genética , Proteínas Proto-Oncogénicas c-ets/genética , Proteínas Represoras/genética , Animales , Transformación Celular Neoplásica , Células Cultivadas , Femenino , Células Madre Hematopoyéticas/patología , Humanos , Leucemia Mieloide/patología , Ratones , Ratones Endogámicos C57BL , Ratones SCID , Proteína ETS de Variante de Translocación 6RESUMEN
The Plant Homeodomain 6 gene (PHF6) encodes a nucleolar and chromatin-associated leukemia tumor suppressor with proposed roles in transcription regulation. However, specific molecular mechanisms controlled by PHF6 remain rudimentarily understood. Here we show that PHF6 engages multiple nucleosome remodeling protein complexes, including nucleosome remodeling and deacetylase, SWI/SNF and ISWI factors, the replication machinery and DNA repair proteins. Moreover, after DNA damage, PHF6 localizes to sites of DNA injury, and its loss impairs the resolution of DNA breaks, with consequent accumulation of single- and double-strand DNA lesions. Native chromatin immunoprecipitation sequencing analyses show that PHF6 specifically associates with difficult-to-replicate heterochromatin at satellite DNA regions enriched in histone H3 lysine 9 trimethyl marks, and single-molecule locus-specific analyses identify PHF6 as an important regulator of genomic stability at fragile sites. These results extend our understanding of the molecular mechanisms controlling hematopoietic stem cell homeostasis and leukemia transformation by placing PHF6 at the crossroads of chromatin remodeling, replicative fork dynamics, and DNA repair.
Asunto(s)
Ensamble y Desensamble de Cromatina , Leucemia , Cromatina/genética , Reparación del ADN , Humanos , Nucleosomas , Proteínas Represoras/genética , Proteínas Represoras/metabolismoRESUMEN
Enhancers control dynamic changes in gene expression and orchestrate the tightly controlled transcriptional circuitries that direct and coordinate cell growth, proliferation, survival, lineage commitment, and differentiation during lymphoid development. Enhancer hijacking and neoenhancer formation at oncogene loci, as well as aberrant activation of oncogene-associated enhancers, can induce constitutive activation of self-perpetuating oncogenic transcriptional circuitries, and contribute to the malignant transformation of immature lymphoid progenitors in acute lymphoblastic leukemia (ALL). In this review, we present recent discoveries of the role of enhancer dynamics in mouse and human lymphoid development, and discuss how genetic and epigenetic alterations of enhancer function can promote leukemogenesis, and potential strategies for targeting the enhancer machinery in the treatment of ALL.
Asunto(s)
Elementos de Facilitación Genéticos , Leucemia-Linfoma Linfoblástico de Células Precursoras , Animales , Carcinogénesis/genética , Diferenciación Celular , Elementos de Facilitación Genéticos/genética , Ratones , Leucemia-Linfoma Linfoblástico de Células Precursoras/genéticaRESUMEN
Relapsed acute lymphoblastic leukaemia (ALL) is associated with resistance to chemotherapy and poor prognosis. Gain-of-function mutations in the 5'-nucleotidase, cytosolic II (NT5C2) gene induce resistance to 6-mercaptopurine and are selectively present in relapsed ALL. Yet, the mechanisms involved in NT5C2 mutation-driven clonal evolution during the initiation of leukaemia, disease progression and relapse remain unknown. Here we use a conditional-and-inducible leukaemia model to demonstrate that expression of NT5C2(R367Q), a highly prevalent relapsed-ALL NT5C2 mutation, induces resistance to chemotherapy with 6-mercaptopurine at the cost of impaired leukaemia cell growth and leukaemia-initiating cell activity. The loss-of-fitness phenotype of NT5C2+/R367Q mutant cells is associated with excess export of purines to the extracellular space and depletion of the intracellular purine-nucleotide pool. Consequently, blocking guanosine synthesis by inhibition of inosine-5'-monophosphate dehydrogenase (IMPDH) induced increased cytotoxicity against NT5C2-mutant leukaemia lymphoblasts. These results identify the fitness cost of NT5C2 mutation and resistance to chemotherapy as key evolutionary drivers that shape clonal evolution in relapsed ALL and support a role for IMPDH inhibition in the treatment of ALL.
Asunto(s)
5'-Nucleotidasa/genética , 5'-Nucleotidasa/metabolismo , Evolución Clonal , Resistencia a Antineoplásicos/genética , Mutación/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Animales , Proliferación Celular , Modelos Animales de Enfermedad , Femenino , Mutación con Ganancia de Función/genética , Guanosina/biosíntesis , Células HEK293 , Humanos , IMP Deshidrogenasa/antagonistas & inhibidores , IMP Deshidrogenasa/metabolismo , Masculino , Mercaptopurina/farmacología , Mercaptopurina/uso terapéutico , Ratones , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Purinas/metabolismo , Receptor Notch1/metabolismo , Recurrencia , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
ZFP36L1 and ZFP36L2 are RNA-binding proteins (RBPs) that interact with AU-rich elements in the 3' untranslated region of mRNA, which leads to mRNA degradation and translational repression. Here we show that mice that lacked ZFP36L1 and ZFP36L2 during thymopoiesis developed a T cell acute lymphoblastic leukemia (T-ALL) dependent on the oncogenic transcription factor Notch1. Before the onset of T-ALL, thymic development was perturbed, with accumulation of cells that had passed through the beta-selection checkpoint without first expressing the T cell antigen receptor beta-chain (TCRbeta). Notch1 expression was higher in untransformed thymocytes in the absence of ZFP36L1 and ZFP36L2. Both RBPs interacted with evolutionarily conserved AU-rich elements in the 3' untranslated region of Notch1 and suppressed its expression. Our data establish a role for ZFP36L1 and ZFP36L2 during thymocyte development and in the prevention of malignant transformation.
Asunto(s)
Proteínas Nucleares/deficiencia , Leucemia-Linfoma Linfoblástico de Células T Precursoras/inmunología , Linfocitos T/inmunología , Timo/inmunología , Tristetraprolina/deficiencia , Secuencia de Aminoácidos , Animales , Factor 1 de Respuesta al Butirato , Secuencia Conservada , Humanos , Inmunofenotipificación , Estimación de Kaplan-Meier , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Proteínas Nucleares/genética , Proteínas Nucleares/inmunología , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/inmunología , Receptor Notch1/genética , Receptor Notch1/inmunología , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Alineación de Secuencia , Timo/crecimiento & desarrollo , Transcripción Genética , Tristetraprolina/genética , Tristetraprolina/inmunologíaRESUMEN
Hematopoietic stem cell (HSC) differentiation is regulated by cell-intrinsic and cell-extrinsic cues. In addition to transcriptional regulation, post-translational regulation may also control HSC differentiation. To test this hypothesis, we visualized the ubiquitin-regulated protein stability of a single transcription factor, c-Myc. The stability of c-Myc protein was indicative of HSC quiescence, and c-Myc protein abundance was controlled by the ubiquitin ligase Fbw7. Fine changes in the stability of c-Myc protein regulated the HSC gene-expression signature. Using whole-genome genomic approaches, we identified specific regulators of HSC function directly controlled by c-Myc binding; however, adult HSCs and embryonic stem cells sensed and interpreted c-Myc-regulated gene expression in distinct ways. Our studies show that a ubiquitin ligase-substrate pair can orchestrate the molecular program of HSC differentiation.
Asunto(s)
Diferenciación Celular/fisiología , Células Madre Hematopoyéticas/citología , Ubiquitina-Proteína Ligasas/inmunología , Animales , Ciclo Celular/genética , Ciclo Celular/inmunología , Proteínas de Ciclo Celular/inmunología , Diferenciación Celular/genética , Inmunoprecipitación de Cromatina , Citometría de Flujo , Células Madre Hematopoyéticas/inmunología , Células Madre Hematopoyéticas/metabolismo , Ratones , Ratones Noqueados , Proteínas Proto-Oncogénicas c-myc/inmunologíaRESUMEN
Activating mutations in cytosolic 5'-nucleotidase II (NT5C2) are considered to drive relapse formation in acute lymphoblastic leukemia (ALL) by conferring purine analog resistance. To examine the clinical effects of NT5C2 mutations in relapsed ALL, we analyzed NT5C2 in 455 relapsed B-cell precursor ALL patients treated within the ALL-REZ BFM 2002 relapse trial using sequencing and sensitive allele-specific real-time polymerase chain reaction. We detected 110 NT5C2 mutations in 75 (16.5%) of 455 B-cell precursor ALL relapses. Two-thirds of relapses harbored subclonal mutations and only one-third harbored clonal mutations. Event-free survival after relapse was inferior in patients with relapses with clonal and subclonal NT5C2 mutations compared with those without (19% and 25% vs 53%, P < .001). However, subclonal, but not clonal, NT5C2 mutations were associated with reduced event-free survival in multivariable analysis (hazard ratio, 1.89; 95% confidence interval, 1.28-2.69; P = .001) and with an increased rate of nonresponse to relapse treatment (subclonal 32%, clonal 12%, wild type 9%, P < .001). Nevertheless, 27 (82%) of 33 subclonal NT5C2 mutations became undetectable at the time of nonresponse or second relapse, and in 10 (71%) of 14 patients subclonal NT5C2 mutations were undetectable already after relapse induction treatment. These results show that subclonal NT5C2 mutations define relapses associated with high risk of treatment failure in patients and at the same time emphasize that their role in outcome is complex and goes beyond mutant NT5C2 acting as a targetable driver during relapse progression. Sensitive, prospective identification of NT5C2 mutations is warranted to improve the understanding and treatment of this aggressive ALL relapse subtype.
Asunto(s)
5'-Nucleotidasa/genética , Mutación , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Adolescente , Alelos , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Biomarcadores , Niño , Preescolar , Análisis Mutacional de ADN , Femenino , Frecuencia de los Genes , Humanos , Lactante , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Pronóstico , Recurrencia , Adulto JovenRESUMEN
The nuclear receptor-binding SET domain (NSD) family of histone methyltransferases is associated with various malignancies, including aggressive acute leukemia with NUP98-NSD1 translocation. While NSD proteins represent attractive drug targets, their catalytic SET domains exist in autoinhibited conformation, presenting notable challenges for inhibitor development. Here, we employed a fragment-based screening strategy followed by chemical optimization, which resulted in the development of the first-in-class irreversible small-molecule inhibitors of the nuclear receptor-binding SET domain protein 1 (NSD1) SET domain. The crystal structure of NSD1 in complex with covalently bound ligand reveals a conformational change in the autoinhibitory loop of the SET domain and formation of a channel-like pocket suitable for targeting with small molecules. Our covalent lead-compound BT5-demonstrates on-target activity in NUP98-NSD1 leukemia cells, including inhibition of histone H3 lysine 36 dimethylation and downregulation of target genes, and impaired colony formation in an NUP98-NSD1 patient sample. This study will facilitate the development of the next generation of potent and selective inhibitors of the NSD histone methyltransferases.
Asunto(s)
Antineoplásicos/farmacología , Inhibidores Enzimáticos/farmacología , Regulación Leucémica de la Expresión Génica , N-Metiltransferasa de Histona-Lisina/antagonistas & inhibidores , Leucocitos/efectos de los fármacos , Proteínas de Complejo Poro Nuclear/genética , Proteínas de Fusión Oncogénica/antagonistas & inhibidores , Antineoplásicos/síntesis química , Sitios de Unión , Inhibidores Enzimáticos/síntesis química , N-Metiltransferasa de Histona-Lisina/genética , N-Metiltransferasa de Histona-Lisina/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Cinética , Leucemia/tratamiento farmacológico , Leucemia/enzimología , Leucemia/genética , Leucemia/patología , Leucocitos/enzimología , Leucocitos/patología , Modelos Moleculares , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/genética , Proteína 1 del Sitio de Integración Viral Ecotrópica Mieloide/metabolismo , Proteínas de Complejo Poro Nuclear/metabolismo , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Transducción de Señal , Especificidad por Sustrato , Células Tumorales CultivadasRESUMEN
Mutations in the cytosolic 5' nucleotidase II (NT5C2) gene drive resistance to thiopurine chemotherapy in relapsed acute lymphoblastic leukemia (ALL). Mechanistically, NT5C2 mutant proteins have increased nucleotidase activity as a result of altered activating and autoregulatory switch-off mechanisms. Leukemias with NT5C2 mutations are chemoresistant to 6-mercaptopurine yet show impaired proliferation and self-renewal. Direct targeting of NT5C2 or inhibition of compensatory pathways active in NT5C2 mutant cells may antagonize the emergence of NT5C2 mutant clones driving resistance and relapse in ALL.
Asunto(s)
5'-Nucleotidasa , Proliferación Celular , Mercaptopurina/uso terapéutico , Mutación , Proteínas de Neoplasias , Leucemia-Linfoma Linfoblástico de Células Precursoras , Proliferación Celular/efectos de los fármacos , Proliferación Celular/genética , Resistencia a Antineoplásicos/efectos de los fármacos , Resistencia a Antineoplásicos/genética , Humanos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimología , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologíaRESUMEN
Chronic lymphocytic leukaemia (CLL) is a frequent disease in which the genetic alterations determining the clinicobiological behaviour are not fully understood. Here we describe a comprehensive evaluation of the genomic landscape of 452 CLL cases and 54 patients with monoclonal B-lymphocytosis, a precursor disorder. We extend the number of CLL driver alterations, including changes in ZNF292, ZMYM3, ARID1A and PTPN11. We also identify novel recurrent mutations in non-coding regions, including the 3' region of NOTCH1, which cause aberrant splicing events, increase NOTCH1 activity and result in a more aggressive disease. In addition, mutations in an enhancer located on chromosome 9p13 result in reduced expression of the B-cell-specific transcription factor PAX5. The accumulative number of driver alterations (0 to ≥4) discriminated between patients with differences in clinical behaviour. This study provides an integrated portrait of the CLL genomic landscape, identifies new recurrent driver mutations of the disease, and suggests clinical interventions that may improve the management of this neoplasia.
Asunto(s)
Leucemia Linfocítica Crónica de Células B/genética , Mutación/genética , Regiones no Traducidas 3'/genética , Empalme Alternativo/genética , Linfocitos B/metabolismo , Proteínas Portadoras/genética , Cromosomas Humanos Par 9/genética , Análisis Mutacional de ADN , ADN de Neoplasias/genética , Proteínas de Unión al ADN , Elementos de Facilitación Genéticos/genética , Genómica , Humanos , Leucemia Linfocítica Crónica de Células B/metabolismo , Leucemia Linfocítica Crónica de Células B/patología , Proteínas del Tejido Nervioso/genética , Proteínas Nucleares/genética , Factor de Transcripción PAX5/biosíntesis , Factor de Transcripción PAX5/genética , Proteína Tirosina Fosfatasa no Receptora Tipo 11/genética , Receptor Notch1/genética , Receptor Notch1/metabolismo , Factores de Transcripción/genéticaRESUMEN
T-cell acute lymphoblastic leukaemia (T-ALL) is a haematological malignancy with a dismal overall prognosis, including a relapse rate of up to 25%, mainly because of the lack of non-cytotoxic targeted therapy options. Drugs that target the function of key epigenetic factors have been approved in the context of haematopoietic disorders, and mutations that affect chromatin modulators in a variety of leukaemias have recently been identified; however, 'epigenetic' drugs are not currently used for T-ALL treatment. Recently, we described that the polycomb repressive complex 2 (PRC2) has a tumour-suppressor role in T-ALL. Here we delineated the role of the histone 3 lysine 27 (H3K27) demethylases JMJD3 and UTX in T-ALL. We show that JMJD3 is essential for the initiation and maintenance of T-ALL, as it controls important oncogenic gene targets by modulating H3K27 methylation. By contrast, we found that UTX functions as a tumour suppressor and is frequently genetically inactivated in T-ALL. Moreover, we demonstrated that the small molecule inhibitor GSKJ4 (ref. 5) affects T-ALL growth, by targeting JMJD3 activity. These findings show that two proteins with a similar enzymatic function can have opposing roles in the context of the same disease, paving the way for treating haematopoietic malignancies with a new category of epigenetic inhibitors.
Asunto(s)
Histona Demetilasas/metabolismo , Histona Demetilasas con Dominio de Jumonji/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimología , Animales , Benzazepinas/farmacología , Epigénesis Genética/efectos de los fármacos , Histona Demetilasas/genética , Histonas/química , Histonas/metabolismo , Histona Demetilasas con Dominio de Jumonji/antagonistas & inhibidores , Lisina/metabolismo , Metilación/efectos de los fármacos , Ratones , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Pirimidinas/farmacología , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismoRESUMEN
Activating mutations of NOTCH1 (a well-known oncogene in T-cell acute lymphoblastic leukemia) are present in â¼4-13% of chronic lymphocytic leukemia (CLL) cases, where they are associated with disease progression and chemorefractoriness. However, the specific role of NOTCH1 in leukemogenesis remains to be established. Here, we report that the active intracellular portion of NOTCH1 (ICN1) is detectable in â¼50% of peripheral blood CLL cases lacking gene mutations. We identify a "NOTCH1 gene-expression signature" in CLL cells, and show that this signature is significantly enriched in primary CLL cases expressing ICN1, independent of NOTCH1 mutation. NOTCH1 target genes include key regulators of B-cell proliferation, survival, and signal transduction. In particular, we show that NOTCH1 transactivates MYC via binding to B-cell-specific regulatory elements, thus implicating this oncogene in CLL development. These results significantly extend the role of NOTCH1 in CLL pathogenesis, and have direct implications for specific therapeutic targeting.
Asunto(s)
Linfocitos B/fisiología , Leucemia Linfocítica Crónica de Células B/genética , Receptor Notch1/genética , Linfocitos B/patología , Proliferación Celular/genética , Regulación Leucémica de la Expresión Génica , Genes myc , Humanos , Mutación , Receptor Notch1/sangreRESUMEN
The Notch1 gene is a major oncogenic driver and therapeutic target in T-cell acute lymphoblastic leukemia (T-ALL). However, inhibition of NOTCH signaling with γ-secretase inhibitors (GSIs) has shown limited antileukemic activity in clinical trials. Here we performed an expression-based virtual screening to identify highly active antileukemic drugs that synergize with NOTCH1 inhibition in T-ALL. Among these, withaferin A demonstrated the strongest cytotoxic and GSI-synergistic antileukemic effects in vitro and in vivo. Mechanistically, network perturbation analyses showed eIF2A-phosphorylation-mediated inhibition of protein translation as a critical mediator of the antileukemic effects of withaferin A and its interaction with NOTCH1 inhibition. Overall, these results support a role for anti-NOTCH1 therapies and protein translation inhibitor combinations in the treatment of T-ALL.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Biosíntesis de Proteínas/efectos de los fármacos , Receptor Notch1/antagonistas & inhibidores , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Línea Celular Tumoral , Sinergismo Farmacológico , Inhibidores Enzimáticos/uso terapéutico , Perfilación de la Expresión Génica , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Terapia Molecular Dirigida/métodos , Fosforilación/efectos de los fármacos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patología , Receptor Notch1/genética , Receptor Notch1/metabolismo , Transducción de Señal/efectos de los fármacos , Witanólidos/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto , eIF-2 Quinasa/metabolismoRESUMEN
Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas frequently associated with poor prognosis and for which genetic mechanisms of transformation remain incompletely understood. Using RNA sequencing and targeted sequencing, here we identify a recurrent in-frame deletion (VAV1 Δ778-786) generated by a focal deletion-driven alternative splicing mechanism as well as novel VAV1 gene fusions (VAV1-THAP4, VAV1-MYO1F, and VAV1-S100A7) in PTCL. Mechanistically these genetic lesions result in increased activation of VAV1 catalytic-dependent (MAPK, JNK) and non-catalytic-dependent (nuclear factor of activated T cells, NFAT) VAV1 effector pathways. These results support a driver oncogenic role for VAV1 signaling in the pathogenesis of PTCL.