RESUMEN
Targeting nucleotide biosynthesis is a proven strategy for the treatment of cancer but is limited by toxicity, reflecting the fundamental nucleotide requirement of dividing cells. The rate limiting step in de novo pyrimidine synthesis is of interest, being catalyzed by two homologous enzymes, CTP synthase 1 (CTPS1) and CTPS2, that could be differentially targeted. Herein, analyses of publicly available datasets identified an essential role for CTPS1 in multiple myeloma (MM), linking high expression of CTPS1 (but not CTPS2) with advanced disease and poor outcomes. In cellular experiments, CTPS1 knockout induced apoptosis of MM cell lines. Exposure of MM cells to STP-B, a novel and highly selective pharmacological inhibitor of CTPS1, inhibited proliferation, induced S phase arrest and led to cell death by apoptosis. Mechanistically, CTPS1 inhibition by STP-B activated DNA damage response (DDR) pathways and induced double-strand DNA breaks which accumulated in early S phase. Combination of STP-B with pharmacological inhibitors of key components of the DDR pathway (ATR, CHEK1 or WEE1) resulted in synergistic growth inhibition and early apoptosis. Taken together, these findings identify CTPS1 as a promising new target in MM, either alone or in combination with DDR pathway inhibition.
Asunto(s)
Mieloma Múltiple , Humanos , Mieloma Múltiple/tratamiento farmacológico , Mieloma Múltiple/genética , Apoptosis , Muerte Celular , Proteínas de la Ataxia Telangiectasia Mutada , Nucleótidos , Daño del ADN , Línea Celular Tumoral , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/metabolismo , Proteínas Tirosina Quinasas , Proteínas de Ciclo Celular/metabolismoRESUMEN
Relapse is associated with therapy resistance and is a major cause of death in acute myeloid leukemia (AML). It is thought to result from the accretion of therapy-refractory leukemic stem cells. Genetic and transcriptional changes that are recurrently gained at relapse are likely to contribute to the increased stemness and decreased therapy responsiveness at this disease stage. Despite the recent approval of several targeted drugs, chemotherapy with cytosine arabinoside and anthracyclines is still the mainstay of AML therapy. Accordingly, a number of studies have investigated genetic and gene expression changes between diagnosis and relapse of patients subjected to such treatment. Genetic alterations recurrently acquired at relapse were identified, but were restricted to small proportions of patients, and their functional characterization is still largely pending. In contrast, the expression of a substantial number of genes was altered consistently between diagnosis and recurrence of AML. Recent studies corroborated the roles of the upregulation of SOCS2 and CALCRL and of the downregulation of MTSS1 and KDM6A in therapy resistance and/or stemness of AML. These findings spur the assumption that functional investigations of genes consistently altered at recurrence of AML have the potential to promote the development of novel targeted drugs that may help to improve the outcome of this currently often fatal disease.
Asunto(s)
Proteína Similar al Receptor de Calcitonina/biosíntesis , Regulación Leucémica de la Expresión Génica , Histona Demetilasas/biosíntesis , Leucemia Mieloide Aguda , Proteínas de Microfilamentos/biosíntesis , Proteínas de Neoplasias/biosíntesis , Células Madre Neoplásicas/metabolismo , Proteínas Supresoras de la Señalización de Citocinas/biosíntesis , Humanos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patología , Leucemia Mieloide Aguda/terapia , RecurrenciaRESUMEN
All-trans retinoic acid (atRA) has a dramatic impact on the survival of patients with acute promyelocytic leukemia, but its therapeutic value in other types of acute myeloid leukemia (AML) has so far remained unclear. Given that AML is a stem cell-driven disease, recent studies have addressed the effects of atRA on leukemic stem cells (LSCs). atRA promoted stemness of MLL-AF9-driven AML in an Evi1-dependent manner but had the opposite effect in Flt3-ITD/Nup98-Hoxd13-driven AML. Overexpression of the stem cell-associated transcription factor EVI1 predicts a poor prognosis in AML, and is observed in different genetic subtypes, including cytogenetically normal AML. Here, we therefore investigated the effects of Evi1 in a mouse model for cytogenetically normal AML, which rests on the combined activity of Flt3-ITD and Npm1c mutations. Experimental expression of Evi1 on this background strongly promoted disease aggressiveness. atRA inhibited leukemia cell viability and stem cell-related properties, and these effects were counteracted by overexpression of Evi1. These data further underscore the complexity of the responsiveness of AML LSCs to atRA and point out the need for additional investigations which may lay a foundation for a precision medicine-based use of retinoids in AML.
RESUMEN
Overexpression of IL2RA, which encodes the alpha chain of the IL2 receptor, is associated with chemotherapy resistance and poor outcome in acute myeloid leukemia (AML). The clinical potential of anti-IL2RA therapy is, therefore, being explored in early-stage clinical trials. Notwithstanding, only very limited information regarding the biological function of IL2RA in AML is available. Using genetic manipulation of IL2RA expression as well as antibody-mediated inhibition of IL2RA in human cell lines, mouse models, and primary patient samples, we investigated the effects of IL2RA on AML cell proliferation and apoptosis, and on pertinent signaling pathways. The impact of IL2RA on the properties of leukemic stem cells (LSC) and on leukemogenesis were queried. IL2RA promoted proliferation and cell-cycle activity and inhibited apoptosis in human AML cell lines and primary cells. These phenotypes were accompanied by corresponding alterations in cell-cycle machinery and in pathways associated with cell survival and apoptosis. The biological roles of IL2RA were confirmed in two genetically distinct AML mouse models, revealing that IL2RA inhibits differentiation, promotes stem cell-related properties, and is required for leukemogenesis. IL2RA antibodies inhibited leukemic, but not normal, hematopoietic cells and synergized with other antileukemic agents in this regard. Collectively, these data show for the first time that IL2RA plays key biological roles in AML and underscore its value as a potential therapeutic target in this disease. SIGNIFICANCE: This study identifies IL2RA as a potential therapeutic target in AML, where it is shown to regulate proliferation, differentiation, apoptosis, stem cell-related properties, and leukemogenesis.
Asunto(s)
Subunidad alfa del Receptor de Interleucina-2/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Animales , Anticuerpos Monoclonales/farmacología , Apoptosis/genética , Estudios de Casos y Controles , Línea Celular Tumoral , Proliferación Celular/genética , Femenino , Regulación Leucémica de la Expresión Génica , Humanos , Subunidad alfa del Receptor de Interleucina-2/inmunología , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/mortalidad , Ratones Endogámicos C57BL , Pronóstico , Células Madre/patología , Tirosina Quinasa 3 Similar a fms/genéticaRESUMEN
Acute myeloid leukemia (AML) is an aggressive, often fatal hematopoietic malignancy. All-trans retinoic acid (atRA), one of the first molecularly targeted drugs in oncology, has greatly improved the outcome of a subtype of AML, acute promyelocytic leukemia (APL). In contrast, atRA has so far provided little therapeutic benefit in the much larger group of patients with non-APL AML. Attempts to identify genetically or molecularly defined subgroups of patients that may respond to atRA have not yielded consistent results. Since AML is a stem cell-driven disease, understanding the effectiveness of atRA may require an appreciation of its impact on AML stem cells. Recent studies reported that atRA decreased stemness of AML with an FLT3-ITD mutation, yet increased it in AML1-ETO driven or EVI1-overexpressing AML. This review summarizes the role of atRA in normal hematopoiesis and in AML, focusing on its impact on AML stem cells.
Asunto(s)
Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Promielocítica Aguda/tratamiento farmacológico , Células Madre Neoplásicas/efectos de los fármacos , Tretinoina/farmacología , Animales , Apoptosis/efectos de los fármacos , Hematopoyesis/efectos de los fármacos , HumanosRESUMEN
The neuropeptide CGRP, acting through the G-protein coupled receptor CALCRL and its coreceptor RAMP1, plays a key role in migraines, which has led to the clinical development of several inhibitory compounds. Recently, high CALCRL expression has been shown to be associated with a poor prognosis in acute myeloid leukemia (AML). We investigate, therefore, the functional role of the CGRP-CALCRL axis in AML. To this end, in silico analyses, human AML cell lines, primary patient samples, and a C57BL/6-based mouse model of AML are used. We find that CALCRL is up-regulated at relapse of AML, in leukemic stem cells (LSCs) versus bulk leukemic cells, and in LSCs versus normal hematopoietic stem cells. CGRP protects receptor-positive AML cell lines and primary AML samples from apoptosis induced by cytostatic drugs used in AML therapy, and this effect is inhibited by specific antagonists. Furthermore, the CGRP antagonist olcegepant increases differentiation and reduces the leukemic burden as well as key stem cell properties in a mouse model of AML. These data provide a basis for further investigations into a possible role of CGRP-CALCRL inhibition in the therapy of AML.
Asunto(s)
Péptido Relacionado con Gen de Calcitonina/metabolismo , Proteína Similar al Receptor de Calcitonina/metabolismo , Resistencia a Antineoplásicos , Leucemia Mieloide Aguda/metabolismo , Células Madre Neoplásicas/metabolismo , Animales , Antibióticos Antineoplásicos/farmacología , Antibióticos Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Proteína Similar al Receptor de Calcitonina/antagonistas & inhibidores , Línea Celular Tumoral , Daunorrubicina/farmacología , Daunorrubicina/uso terapéutico , Dipéptidos/farmacología , Dipéptidos/uso terapéutico , Femenino , Células Madre Hematopoyéticas/metabolismo , Humanos , Leucemia Mieloide Aguda/tratamiento farmacológico , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad , Piperazinas , Quinazolinas/farmacología , Quinazolinas/uso terapéutico , Transducción de SeñalRESUMEN
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.
Asunto(s)
Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Proteínas Supresoras de la Señalización de Citocinas/genética , Animales , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Humanos , Leucemia Mieloide Aguda/diagnóstico , Ratones , Células Madre Neoplásicas/patología , PronósticoRESUMEN
The complement, coagulation, and fibrinolytic systems are crucial for the maintenance of tissue homeostasis. To date numerous interactions and cross-talks have been identified between these cascades. In line with this, here we propose a novel, hitherto unknown interaction between the complement inhibitor C4b-binding protein (C4BP) and plasminogen of the fibrinolytic pathway. Binding of C4BP to Streptococcus pneumoniae is a known virulence mechanism of this pathogen and it was increased in the presence of plasminogen. Interestingly, the acute phase variant of C4BP lacking the ß-chain and protein S binds plasminogen much stronger than the main isoform containing the ß-chain and protein S. Indeed, the complement control protein (CCP) 8 domain of C4BP, which would otherwise be sterically hindered by the ß-chain, primarily mediates this interaction. Moreover, the lysine-binding sites in plasminogen kringle domains facilitate the C4BP-plasminogen interaction. Furthermore, C4BP readily forms complexes with plasminogen in fluid phase and such complexes are present in human serum and plasma. Importantly, whereas the presence of plasminogen did not affect the factor I cofactor activity of C4BP, the activation of plasminogen by urokinase-type plasminogen activator to active plasmin was significantly augmented in the presence of C4BP. Taken together, our data demonstrate a novel interaction between two proteins of the complement and fibrinolytic system. Most complexes might be formed during the acute phase of inflammation and have an effect on the homeostasis at the site of injury or acute inflammation.