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T-cell lymphoblastic lymphoma (T-LBL) and T-cell acute lymphoblastic leukemia (T-ALL) have common and distinguishing clinical and molecular features. Molecular prognostic factors are needed for T-LBL. We assessed the prevalence and prognostic impact of the T-cell receptor ß (TRB)::NOTCH1 fusion in 192 T-LBL and 167 pediatric T-ALL patients, using novel multiplex PCR and genomic capture high-throughput sequencing techniques. The fusion was detected in twelve T-LBL patients (6.3 %) but in none of the T-ALL patients (p=0.0006, Fisher's exact test). In T-LBL, the TRB::NOTCH1 fusion was associated with a significantly higher incidence of relapse (67% versus 17% in gene fusion-negative patients, p<0.001, Fisher's exact test). The breakpoint in TRB, was most frequently located in J2-7 (n=6). In NOTCH1, the breakpoints varied between exon 24 and 27. Consequently, a truncated NOTCH1 with its dimerization, regulation and signal transduction domains gets controlled by strong TRB enhancer elements. This study reveals a novel recurrent genetic variant with significant prognostic relevance in T-LBL, which was absent in T-ALL. The TRB::NOTCH1 fusion in T-LBL suggests a possible unique pathogenic mechanism divergent from T-ALL. Further studies will validate the role of the TRB::NOTCH1 fusion as prognostic marker in T-LBL and elucidate its pathogenic mechanisms.
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Persistence of residual disease after induction chemotherapy is a strong predictor of relapse in acute lymphoblastic leukemia (ALL). The bone marrow microenvironment may support escape from treatment. Using three-dimensional fluorescence imaging of ten primary ALL xenografts we identified sites of predilection in the bone marrow for resistance to induction with dexamethasone, vincristine and doxorubicin. We detected B-cell precursor ALL cells predominantly in the perisinusoidal space at early engraftment and after chemotherapy. The spatial distribution of T-ALL cells was more widespread with contacts to endosteum, nestin+ pericytes and sinusoids. Dispersion of T-ALL cells in the bone marrow increased under chemotherapeutic pressure. A subset of slowly dividing ALL cells was transiently detected upon shortterm chemotherapy, but not at residual disease after chemotherapy, challenging the notion that ALL cells escape treatment by direct induction of a dormant state in the niche. These lineage-dependent differences point to niche interactions that may be more specifically exploitable to improve treatment.
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Linfoma de Burkitt , Leucemia Bifenotípica Aguda , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Leucemia-Linfoma Linfoblástico de Células Precursoras , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Humanos , Médula Ósea , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Linfoma de Burkitt/tratamiento farmacológico , Microambiente TumoralRESUMEN
Modern cancer therapies increased the survival rates of acute myeloid leukemia (AML) patients tremendously. However, the complexity of the disease and the identification of new targets require the adaptation of treatment protocols to reduce side effects and increase benefit for the patients. One key regulator of leukemogenesis and chemotherapy resistance in AML is the Hedgehog (HH) signaling pathway. It is deregulated in numerous cancer entities and inhibition of its downstream transcription factors GLI translates into anti-leukemic effects. One major regulator of GLI is BRD4, a BET family member with epigenetic functions. We investigated the effect of ZEN-3365, a novel BRD4 inhibitor, on AML cells in regard to the HH pathway. We show that ZEN-3365 alone or in combination with GANT-61 reduced GLI promoter activity, cell proliferation and colony formation in AML cell lines and primary cells. Our findings strongly support the evaluation of the BRD4 inhibitor ZEN-3365 as a new therapeutic option in AML.
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Antineoplásicos/farmacología , Proteínas de Ciclo Celular/antagonistas & inhibidores , Proteínas Hedgehog/metabolismo , Leucemia Mieloide Aguda/tratamiento farmacológico , Factores de Transcripción/antagonistas & inhibidores , Proteínas de Ciclo Celular/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Humanos , Leucemia Mieloide Aguda/metabolismo , Transducción de Señal/efectos de los fármacos , Factores de Transcripción/metabolismoRESUMEN
Aberrant activation of the hedgehog (HH) pathway is observed in many neoplasms, including acute myeloid leukemia (AML). The glioma-associated oncogene homolog (GLI) transcription factors are the main downstream effectors of the HH signaling cascade and are responsible for the proliferation and maintenance of leukemic stem cells, which support chemotherapy resistance and leukemia relapse. Cytarabine (Ara-C)-resistant variants of AML cell lines were established through long-term cultivation with successively increasing Ara-C concentrations. Subsequently, differences in GLI expression were analyzed by RT-qPCR. GLI3 mRNA levels were detectable in parental Kasumi-1, OCI-AML3, and OCI-AML5 cells, whereas GLI3 expression was completely silenced in all resistant counterparts. Therefore, we generated GLI3-knockdown cell lines using small hairpin RNAs (shRNA) and evaluated their sensitivity to Ara-C in vitro. The knockdown of GLI3 partly abolished the effect of Ara-C on colony formation and induction of apoptosis, indicating that GLI3 downregulation results in Ara-C resistance. Moreover, we analyzed the expression of several genes involved in Ara-C metabolism and transport. Knockdown of GLI3 resulted in the upregulation of SAM and HD domain-containing protein 1 (SAMHD1), cytidine deaminase (CDA), and ATP-binding cassette C11 (ABCC11)/multidrug resistance-associated protein 8 (MRP8), each of which has been identified as a predictive marker for Ara-C response in acute myeloid leukemia. Our results demonstrate that GLI3 downregulation is a potential mechanism to induce chemotherapy resistance in AML.
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Apoptosis/genética , Citarabina/farmacología , Resistencia a Antineoplásicos/genética , Leucemia Mieloide Aguda/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Transducción de Señal/genética , Proteína Gli3 con Dedos de Zinc/metabolismo , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Citarabina/metabolismo , Citidina Desaminasa/genética , Citidina Desaminasa/metabolismo , Regulación hacia Abajo , Técnicas de Silenciamiento del Gen , Silenciador del Gen , Humanos , Leucemia Mieloide Aguda/genética , Proteínas del Tejido Nervioso/genética , Proteína 1 que Contiene Dominios SAM y HD/genética , Proteína 1 que Contiene Dominios SAM y HD/metabolismo , Transducción de Señal/efectos de los fármacos , Proteína Gli3 con Dedos de Zinc/genéticaRESUMEN
Introduction: Myeloid malignancies are caused by uncontrolled proliferation of neoplastic cells and lack of mature hematopoietic cells. Beside intrinsic genetic and epigenetic alterations within the neoplastic population, abnormal function of the bone marrow stroma promotes the neoplastic process. To overcome the supportive action of the microenvironment, recent research focuses on the development of targeted therapies, inhibiting the interaction of malignant cells and niche cells.Areas covered: This review covers regulatory networks and potential druggable pathways within the hematopoietic stem cell niche. Recent insights into the cell-to-cell interactions in the bone marrow microenvironment are presented. We performed literature searches using PubMed Database from 2000 to the present.Expert opinion: Future therapy of myeloid malignancies must focus on targeted, personalized treatment addressing specific alterations within the malignant and the supporting niche cells. This includes treatments to overcome resistance mechanisms against chemotherapeutic agents mediated by supporting microenvironment. Novel techniques employing sequencing approaches, Crisp/Cas9, or transgenic mouse models are required to elucidate specific interactions between components of the bone marrow niche to identify new therapeutic targets.
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Neoplasias Hematológicas/terapia , Terapia Molecular Dirigida , Trastornos Mieloproliferativos/terapia , Animales , Antineoplásicos/farmacología , Células de la Médula Ósea/citología , Neoplasias Hematológicas/patología , Humanos , Ratones , Ratones Transgénicos , Trastornos Mieloproliferativos/patología , Nicho de Células Madre/fisiología , Células del Estroma/citología , Microambiente TumoralRESUMEN
The bone marrow is the home of hematopoiesis and is therefore a hotspot for the development of hematopoietic diseases. Complex interactions between the bone marrow microenvironment and hematopoietic stem cells must find a balance between proliferation, differentiation and homeostasis of the stem cell compartment. Changes in this tightly regulated network can provoke malignant transformation, leading to hematopoietic diseases. Here we focus on acute myeloid leukemia (AML), since this is the most frequent acute leukemia in adulthood with very poor overall survival rates and where relapse after chemotherapy continues to be a major challenge, driving demand for new therapeutic strategies. Current research is focusing on the identification of specific interactions between leukemic blasts and their niche components, which may be exploited as novel treatment targets along with induction chemotherapy. Significant progress has been gained over the last few years in the field of high-resolution imaging. Confocal ex vivo and intravital microscopy have revealed a detailed map of bone marrow structures and components; as well as identifying numerous alterations in the stem cell niche that correspond to disease progression. However, the underlying mechanisms are still not completely understood and due to the complexity, their elucidation remains a challenging. This review discusses the constitution of the AML niche in the bone marrow, the improvement in visualization of the complex three-dimensional niche structures and points out new therapeutic strategies to increase the overall survival of AML patients.
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The microenvironment shapes cell behavior and determines metastatic outcomes of tumors. We addressed how microenvironmental cues control tumor cell invasion in pediatric medulloblastoma (MB). We show that bFGF promotes MB tumor cell invasion through FGF receptor (FGFR) in vitro and that blockade of FGFR represses brain tissue infiltration in vivo. TGF-ß regulates pro-migratory bFGF function in a context-dependent manner. Under low bFGF, the non-canonical TGF-ß pathway causes ROCK activation and cortical translocation of ERK1/2, which antagonizes FGFR signaling by inactivating FGFR substrate 2 (FRS2), and promotes a contractile, non-motile phenotype. Under high bFGF, negative-feedback regulation of FRS2 by bFGF-induced ERK1/2 causes repression of the FGFR pathway. Under these conditions, TGF-ß counters inactivation of FRS2 and restores pro-migratory signaling. These findings pinpoint coincidence detection of bFGF and TGF-ß signaling by FRS2 as a mechanism that controls tumor cell invasion. Thus, targeting FRS2 represents an emerging strategy to abrogate aberrant FGFR signaling.
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Factor 2 de Crecimiento de Fibroblastos/farmacología , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Transducción de Señal/efectos de los fármacos , Factor de Crecimiento Transformador beta/farmacología , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Neoplasias Cerebelosas/metabolismo , Neoplasias Cerebelosas/patología , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Humanos , Meduloblastoma/metabolismo , Meduloblastoma/patología , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 3 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Quinasas Asociadas a rho/antagonistas & inhibidores , Quinasas Asociadas a rho/genética , Quinasas Asociadas a rho/metabolismoRESUMEN
Receptor tyrosine kinase (RTK)-dependent signaling has been implicated in the pathogenesis of acute lymphoblastic leukemia (ALL) of childhood. However, the RTK-dependent signaling state and its interpretation with regard to biological behavior are often elusive. To decipher signaling circuits that link RTK activity with biological output in vivo, we established patient-derived xenograft ALL (PDX-ALL) models with dependencies on fms-like tyrosine kinase 3 (FLT3) and platelet-derived growth factor receptor ß (PDGFRB), which were interrogated by phosphoproteomics using iTRAQ mass spectrometry. Signaling circuits were determined by receptor type and cellular context with few generic features, among which we identified group I p21-activated kinases (PAKs) as potential therapeutic targets. Growth factor stimulation markedly increased catalytic activities of PAK1 and PAK2. RNA interference (RNAi)-mediated or pharmacological inhibition of PAKs using allosteric or adenosine triphosphate (ATP)-competitive compounds attenuated cell growth and increased apoptosis in vitro. Notably, PAK1- or PAK2-directed RNAi enhanced the antiproliferative effects of the type III RTK and protein kinase C inhibitor midostaurin. Treatment of FLT3- or PDGFRB-dependent ALLs with ATP-competitive PAK inhibitors markedly decreased catalytic activities of both PAK isoforms. In FLT3-driven ALL, this effect was augmented by coadministration of midostaurin resulting in synergistic effects on growth inhibition and apoptosis. Finally, combined treatment of FLT3 D835H PDX-ALL with the ATP-competitive group I PAK inhibitor FRAX486 and midostaurin in vivo significantly prolonged leukemia progression-free survival compared with midostaurin monotherapy or control. Our study establishes PAKs as potential downstream targets in RTK-dependent ALL of childhood, the inhibition of which might help prevent the selection or acquisition of resistance mutations toward tyrosine kinase inhibitors.
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Antineoplásicos/farmacología , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Quinasas p21 Activadas/antagonistas & inhibidores , Animales , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Niño , Modelos Animales de Enfermedad , Regulación Leucémica de la Expresión Génica/efectos de los fármacos , Humanos , Linfopoyesis/genética , Ratones , Leucemia-Linfoma Linfoblástico de Células Precursoras/etiología , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Tirosina Quinasas/genética , Proteínas Tirosina Quinasas/metabolismo , Proteoma , Resultado del Tratamiento , Ensayos Antitumor por Modelo de Xenoinjerto , Quinasas p21 Activadas/genética , Quinasas p21 Activadas/metabolismoRESUMEN
"Humanised" mouse models have emerged over past years as powerful tools for investigating human haematopoiesis and immunity. They allowed the identification of key factors for the maintenance and function of normal and leukaemic human haematopoietic stem cells. These findings have been widely used to dissect the pathogenesis of multiple myeloid and lymphoid neoplasms, such as acute myeloid leukaemia and acute lymphoblastic leukaemia. Furthermore, these models can serve as a stepping-stone to clinical trials by testing novel drugs that target leukaemic stem cells. The investigation of human immunity in vivo is also of great interest in both the context of understanding the innate and adaptive immune system and responses to viral infections with exclusive human tropism, such as Epstein-Barr virus and human immunodeficiency virus. This review focuses on recent advances in the study of human haematopoiesis and immunity in humanised mouse models, underlining their relevance and limitations.
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Enfermedades Transmisibles/fisiopatología , Enfermedades Transmisibles/terapia , Modelos Animales de Enfermedad , Hematopoyesis , Animales , VIH , Herpesvirus Humano 4 , Humanos , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/fisiopatología , Linfoma/fisiopatología , RatonesRESUMEN
CRISPR-Cas9 based knockout strategies are increasingly used to analyze gene function. However, redundancies and overlapping functions in biological signaling pathways can call for generating multi-gene knockout cells, which remains a relatively laborious process. Here we detail the application of multi-color LentiCRISPR vectors to simultaneously generate single and multiple knockouts in human cells. We provide a complete protocol, including guide RNA design, LentiCRISPR cloning, viral production and transduction, as well as strategies for sorting and screening knockout cells. The validity of the process is demonstrated by the simultaneous deletion of up to four programmed cell death mediators in leukemic cell lines and patient-derived acute lymphoblastic leukemia xenografts, in which single cell cloning is not feasible. This protocol enables any lab with access to basic cellular biology equipment, a biosafety level 2 facility and fluorescence-activated cell sorting capabilities to generate single and multi-gene knockout cell lines or primary cells efficiently within one month.