RESUMO
MYCN amplification occurs in approximately 20-30% of neuroblastoma patients and correlates with poor prognosis. The TH-MYCN transgenic mouse model mimics the development of human high-risk neuroblastoma and provides strong evidence for the oncogenic function of MYCN. In this study, we identified mitotic dysregulation as a hallmark of tumor initiation in the pre-cancerous ganglia from TH-MYCN mice that persists through tumor progression. Single-cell quantitative-PCR of coeliac ganglia from 10-day-old TH-MYCN mice revealed overexpression of mitotic genes in a subpopulation of premalignant neuroblasts at a level similar to single cells derived from established tumors. Prophylactic treatment using antimitotic agents barasertib and vincristine significantly delayed the onset of tumor formation, reduced pre-malignant neuroblast hyperplasia, and prolonged survival in TH-MYCN mice. Analysis of human neuroblastoma tumor cohorts showed a strong correlation between dysregulated mitosis and features of MYCN amplification, such as MYC(N) transcriptional activity, poor overall survival, and other clinical predictors of aggressive disease. To explore the therapeutic potential of targeting mitotic dysregulation, we showed that genetic and chemical inhibition of mitosis led to selective cell death in neuroblastoma cell lines with MYCN over-expression. Moreover, combination therapy with antimitotic compounds and BCL2 inhibitors exploited mitotic stress induced by antimitotics and was synergistically toxic to neuroblastoma cell lines. These results collectively suggest that mitotic dysregulation is a key component of tumorigenesis in early neuroblasts, which can be inhibited by the combination of antimitotic compounds and pro-apoptotic compounds in MYCN-driven neuroblastoma.
Assuntos
Antimitóticos , Neuroblastoma , Humanos , Camundongos , Animais , Proteína Proto-Oncogênica N-Myc/genética , Proteína Proto-Oncogênica N-Myc/metabolismo , Linhagem Celular Tumoral , Camundongos Transgênicos , Neuroblastoma/tratamento farmacológico , Neuroblastoma/genética , Neuroblastoma/patologia , Transformação Celular Neoplásica/genética , Regulação Neoplásica da Expressão GênicaRESUMO
Hematopoietic stem and progenitor cells (HSPCs) rely on a complex interplay among transcription factors (TFs) to regulate differentiation into mature blood cells. A heptad of TFs (FLI1, ERG, GATA2, RUNX1, TAL1, LYL1, LMO2) bind regulatory elements in bulk CD34+ HSPCs. However, whether specific heptad-TF combinations have distinct roles in regulating hematopoietic differentiation remains unknown. We mapped genome-wide chromatin contacts (HiC, H3K27ac, HiChIP), chromatin modifications (H3K4me3, H3K27ac, H3K27me3) and 10 TF binding profiles (heptad, PU.1, CTCF, STAG2) in HSPC subsets (stem/multipotent progenitors plus common myeloid, granulocyte macrophage, and megakaryocyte erythrocyte progenitors) and found TF occupancy and enhancer-promoter interactions varied significantly across cell types and were associated with cell-type-specific gene expression. Distinct regulatory elements were enriched with specific heptad-TF combinations, including stem-cell-specific elements with ERG, and myeloid- and erythroid-specific elements with combinations of FLI1, RUNX1, GATA2, TAL1, LYL1, and LMO2. Furthermore, heptad-occupied regions in HSPCs were subsequently bound by lineage-defining TFs, including PU.1 and GATA1, suggesting that heptad factors may prime regulatory elements for use in mature cell types. We also found that enhancers with cell-type-specific heptad occupancy shared a common grammar with respect to TF binding motifs, suggesting that combinatorial binding of TF complexes was at least partially regulated by features encoded in DNA sequence motifs. Taken together, this study comprehensively characterizes the gene regulatory landscape in rare subpopulations of human HSPCs. The accompanying data sets should serve as a valuable resource for understanding adult hematopoiesis and a framework for analyzing aberrant regulatory networks in leukemic cells.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core , Células-Tronco Hematopoéticas , Humanos , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Regulação da Expressão Gênica , Hematopoese/genética , Cromatina/metabolismoRESUMO
Prokaryotic evolution is influenced by the exchange of genetic information between species through a process referred to as recombination. The rate of recombination is a useful measure for the adaptive capacity of a prokaryotic population. We introduce Rhometa (https://github.com/sid-krish/Rhometa), a new software package to determine recombination rates from shotgun sequencing reads of metagenomes. It extends the composite likelihood approach for population recombination rate estimation and enables the analysis of modern short-read datasets. We evaluated Rhometa over a broad range of sequencing depths and complexities, using simulated and real experimental short-read data aligned to external reference genomes. Rhometa offers a comprehensive solution for determining population recombination rates from contemporary metagenomic read datasets. Rhometa extends the capabilities of conventional sequence-based composite likelihood population recombination rate estimators to include modern aligned metagenomic read datasets with diverse sequencing depths, thereby enabling the effective application of these techniques and their high accuracy rates to the field of metagenomics. Using simulated datasets, we show that our method performs well, with its accuracy improving with increasing numbers of genomes. Rhometa was validated on a real S. pneumoniae transformation experiment, where we show that it obtains plausible estimates of the rate of recombination. Finally, the program was also run on ocean surface water metagenomic datasets, through which we demonstrate that the program works on uncultured metagenomic datasets.
Assuntos
Metagenoma , Metagenômica , Metagenômica/métodos , Metagenoma/genética , Análise de Sequência de DNA/métodos , Funções Verossimilhança , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Software , Recombinação Genética/genética , AlgoritmosRESUMO
Mouse haematopoietic stem cells (HSCs) first emerge at embryonic day 10.5 (E10.5), on the ventral surface of the dorsal aorta, by endothelial-to-haematopoietic transition. We investigated whether mesenchymal stem cells, which provide an essential niche for long-term HSCs (LT-HSCs) in the bone marrow, reside in the aorta-gonad-mesonephros and contribute to the development of the dorsal aorta and endothelial-to-haematopoietic transition. Here we show that mesoderm-derived PDGFRA+ stromal cells (Mesp1der PSCs) contribute to the haemogenic endothelium of the dorsal aorta and populate the E10.5-E11.5 aorta-gonad-mesonephros but by E13.5 were replaced by neural-crest-derived PSCs (Wnt1der PSCs). Co-aggregating non-haemogenic endothelial cells with Mesp1der PSCs but not Wnt1der PSCs resulted in activation of a haematopoietic transcriptional programme in endothelial cells and generation of LT-HSCs. Dose-dependent inhibition of PDGFRA or BMP, WNT and NOTCH signalling interrupted this reprogramming event. Together, aorta-gonad-mesonephros Mesp1der PSCs could potentially be harnessed to manufacture LT-HSCs from endothelium.
Assuntos
Hemangioblastos , Mesonefro , Animais , Aorta , Hematopoese/genética , Células-Tronco Hematopoéticas , Mesoderma , CamundongosRESUMO
Myocardial infarction (MI, or heart attack) is a leading cause of death worldwide. Myocardial ischaemia reperfusion (I/R) injury typical of MI events is also associated with the development of cardiac fibrosis and heart failure in patients. Fibulin-3 is an extracellular matrix component that plays a role in regulating MI response in the heart. In this study, we generated and compared in vitro cardiac spheroids (CSs) from wild type (WT) and fibulin-3 knockout (Fib-3 KO) mice. These were then exposed to pathophysiological changes in oxygen (O2) concentrations to mimic an MI event. We finally measured changes in contractile function, cell death, and mRNA expression levels of cardiovascular disease genes between WT and Fib-3 KO CSs. Our results demonstrated that there are significant differences in growth kinetics and endothelial network formation between WT and Fib-3 KO CSs, however, they respond similarly to changes in O2 concentrations. Fib-3 deficiency resulted in an increase in viability of cells and improvement in contraction frequency and fractional shortening compared to WT I/R CSs. Gene expression analyses demonstrated that Fib-3 deficiency inhibits I/R injury and cardiac fibrosis and promotes angiogenesis in CSs. Altogether, our findings suggest that Fib-3 deficiency makes CSs resistant to I/R injury and associated cardiac fibrosis and helps to improve the vascular network in CSs.
RESUMO
Current preclinicalin vitroandin vivomodels of cardiac injury typical of myocardial infarction (MI, or heart attack) and drug induced cardiotoxicity mimic only a few aspects of these complex scenarios. This leads to a poor translation of findings from the bench to the bedside. In this study, we biofabricated for the first time advancedin vitromodels of MI and doxorubicin (DOX) induced injury by exposing cardiac spheroids (CSs) to pathophysiological changes in oxygen (O2) levels or DOX treatment. Then, contractile function and cell death was analyzed in CSs in control verses I/R and DOX CSs. For a deeper dig into cell death analysis, 3D rendering analyses and mRNA level changes of cardiac damage-related genes were compared in control verses I/R and DOX CSs. Overall,in vitroCSs recapitulated major features typical of thein vivoMI and drug induced cardiac damages, such as adapting intracellular alterations to O2concentration changes and incubation with cardiotoxic drug, mimicking the contraction frequency and fractional shortening and changes in mRNA expression levels for genes regulating sarcomere structure, calcium transport, cell cycle, cardiac remodelling and signal transduction. Taken together, our study supports the use of I/R and DOX CSs as advancedin vitromodels to study MI and DOX-induced cardiac damge by recapitulating their complexin vivoscenario.
Assuntos
Infarto do Miocárdio , Miocárdio , Cardiotoxicidade/metabolismo , Doxorrubicina/farmacologia , Coração , Humanos , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Changes in gene regulation and expression govern orderly transitions from hematopoietic stem cells to terminally differentiated blood cell types. These transitions are disrupted during leukemic transformation, but knowledge of the gene regulatory changes underpinning this process is elusive. We hypothesized that identifying core gene regulatory networks in healthy hematopoietic and leukemic cells could provide insights into network alterations that perturb cell state transitions. A heptad of transcription factors (LYL1, TAL1, LMO2, FLI1, ERG, GATA2, and RUNX1) bind key hematopoietic genes in human CD34+ hematopoietic stem and progenitor cells (HSPCs) and have prognostic significance in acute myeloid leukemia (AML). These factors also form a densely interconnected circuit by binding combinatorially at their own, and each other's, regulatory elements. However, their mutual regulation during normal hematopoiesis and in AML cells, and how perturbation of their expression levels influences cell fate decisions remains unclear. In this study, we integrated bulk and single-cell data and found that the fully connected heptad circuit identified in healthy HSPCs persists, with only minor alterations in AML, and that chromatin accessibility at key heptad regulatory elements was predictive of cell identity in both healthy progenitors and leukemic cells. The heptad factors GATA2, TAL1, and ERG formed an integrated subcircuit that regulates stem cell-to-erythroid transition in both healthy and leukemic cells. Components of this triad could be manipulated to facilitate erythroid transition providing a proof of concept that such regulatory circuits can be harnessed to promote specific cell-type transitions and overcome dysregulated hematopoiesis.
Assuntos
Fator de Transcrição GATA2/genética , Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide Aguda/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Células Eritroides/metabolismo , Células Eritroides/patologia , Redes Reguladoras de Genes , Hematopoese , Humanos , Leucemia Mieloide Aguda/patologia , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Regulador Transcricional ERG/genéticaRESUMO
Terminally differentiated murine osteocytes and adipocytes can be reprogrammed using platelet-derived growth factor-AB and 5-azacytidine into multipotent stem cells with stromal cell characteristics. We have now optimized culture conditions to reprogram human adipocytes into induced multipotent stem (iMS) cells and characterized their molecular and functional properties. Although the basal transcriptomes of adipocyte-derived iMS cells and adipose tissue-derived mesenchymal stem cells were similar, there were changes in histone modifications and CpG methylation at cis-regulatory regions consistent with an epigenetic landscape that was primed for tissue development and differentiation. In a non-specific tissue injury xenograft model, iMS cells contributed directly to muscle, bone, cartilage, and blood vessels, with no evidence of teratogenic potential. In a cardiotoxin muscle injury model, iMS cells contributed specifically to satellite cells and myofibers without ectopic tissue formation. Together, human adipocyte-derived iMS cells regenerate tissues in a context-dependent manner without ectopic or neoplastic growth.
Assuntos
Azacitidina , Fator de Crescimento Derivado de Plaquetas , Adipócitos , Tecido Adiposo , Animais , Azacitidina/farmacologia , Diferenciação Celular , Células Cultivadas , Humanos , Camundongos , Células-Tronco Multipotentes , MúsculosRESUMO
Signals driving aberrant self-renewal in the heterogeneous leukemia stem cell (LSC) pool determine aggressiveness of acute myeloid leukemia (AML). We report that a positive modulator of canonical WNT signaling pathway, RSPO-LGR4, upregulates key self-renewal genes and is essential for LSC self-renewal in a subset of AML. RSPO2/3 serve as stem cell growth factors to block differentiation and promote proliferation of primary AML patient blasts. RSPO receptor, LGR4, is epigenetically upregulated and works through cooperation with HOXA9, a poor prognostic predictor. Blocking the RSPO3-LGR4 interaction by clinical-grade anti-RSPO3 antibody (OMP-131R10/rosmantuzumab) impairs self-renewal and induces differentiation in AML patient-derived xenografts but does not affect normal hematopoietic stem cells, providing a therapeutic opportunity for HOXA9-dependent leukemia.
Assuntos
Leucemia Mieloide/genética , Células-Tronco Neoplásicas/metabolismo , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais/genética , Trombospondinas/genética , Doença Aguda , Animais , Anticorpos Monoclonais/farmacologia , Linhagem Celular Tumoral , Perfilação da Expressão Gênica/métodos , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Células HL-60 , Humanos , Células K562 , Estimativa de Kaplan-Meier , Leucemia Mieloide/tratamento farmacológico , Leucemia Mieloide/metabolismo , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Células-Tronco Neoplásicas/efeitos dos fármacos , Receptores Acoplados a Proteínas G/imunologia , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células THP-1 , Trombospondinas/imunologia , Trombospondinas/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Modulators of epithelial-to-mesenchymal transition (EMT) have recently emerged as novel players in the field of leukemia biology. The mechanisms by which EMT modulators contribute to leukemia pathogenesis, however, remain to be elucidated. Here we show that overexpression of SNAI1, a key modulator of EMT, is a pathologically relevant event in human acute myeloid leukemia (AML) that contributes to impaired differentiation, enhanced self-renewal, and proliferation of immature myeloid cells. We demonstrate that ectopic expression of Snai1 in hematopoietic cells predisposes mice to AML development. This effect is mediated by interaction with the histone demethylase KDM1A/LSD1. Our data shed new light on the role of SNAI1 in leukemia development and identify a novel mechanism of LSD1 corruption in cancer. This is particularly pertinent given the current interest surrounding the use of LSD1 inhibitors in the treatment of multiple different malignancies, including AML.
Assuntos
Transformação Celular Neoplásica , Transição Epitelial-Mesenquimal/genética , Histona Desmetilases/metabolismo , Leucemia Mieloide Aguda/patologia , Fatores de Transcrição da Família Snail/fisiologia , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Células HEK293 , Células HL-60 , Histona Desmetilases/genética , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Camundongos , Camundongos Transgênicos , Ligação Proteica , Fatores de Transcrição da Família Snail/genética , Fatores de Transcrição da Família Snail/metabolismoRESUMO
Inhibition of the Menin (MEN1) and MLL (MLL1, KMT2A) interaction is a potential therapeutic strategy for MLL-rearranged (MLL-r) leukemia. Structure-based design yielded the potent, highly selective, and orally bioavailable small-molecule inhibitor VTP50469. Cell lines carrying MLL rearrangements were selectively responsive to VTP50469. VTP50469 displaced Menin from protein complexes and inhibited chromatin occupancy of MLL at select genes. Loss of MLL binding led to changes in gene expression, differentiation, and apoptosis. Patient-derived xenograft (PDX) models derived from patients with either MLL-r acute myeloid leukemia or MLL-r acute lymphoblastic leukemia (ALL) showed dramatic reductions of leukemia burden when treated with VTP50469. Multiple mice engrafted with MLL-r ALL remained disease free for more than 1 year after treatment. These data support rapid translation of this approach to clinical trials.
Assuntos
Cromatina/efeitos dos fármacos , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Leucemia Mieloide Aguda/tratamento farmacológico , Proteínas Proto-Oncogênicas/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Cromatina/genética , Regulação Leucêmica da Expressão Gênica/genética , Rearranjo Gênico/efeitos dos fármacos , Rearranjo Gênico/genética , Humanos , Leucemia Mieloide Aguda/genética , Camundongos , Proteínas Proto-Oncogênicas/genética , Fatores de Transcrição/efeitos dos fármacos , Fatores de Transcrição/genéticaRESUMO
Inference of ancestry from biological evidence can provide investigative information, especially for unknown DNA donors. Although tools for predicting ancestry have been developing, ancestry research focusing on populations relevant for South Korea is not common and markers are seldom chosen specifically to differentiate Koreans from other East Asian and South East Asian populations. Here, we report ancestry informative markers (AIMs) for distinguishing six East/South East Asian regional populations: China, Japan, Indonesia, Philippines, South Korea and Thailand. Individual genotypes from these six populations were available in PanSNPdb: The HUGO Pan-Asian SNP Database. To select AIMs, we calculated four population divergence metrics for each SNP: Nei's FST, Rosenberg's Informativeness (In), the average absolute allele frequency difference between populations (δFmean) and the maximum allele frequency difference between populations (δFmax). Based on these values, we selected 100 single nucleotide polymorphisms (SNPs) for distinguishing the six populations, 13 of which exhibited large allele frequency differences between Koreans and non-Koreans. To assess the performance of the AIMs, we performed principal coordinates analysis (PCoA) on the individuals from all six populations and inferred ancestral population clusters using the STRUCTURE program. In conclusion, we found that the selected AIMs can be applied to distinguish the six East/South East Asian groups and we suggest the markers in this study will be helpful to establish ancestry panels for Korea and neighbouring populations.
Assuntos
Povo Asiático/genética , Marcadores Genéticos , Genética Populacional , Polimorfismo de Nucleotídeo Único , Ásia , Impressões Digitais de DNA , Bases de Dados Genéticas , Frequência do Gene , Genótipo , Humanos , Análise de Componente PrincipalRESUMO
Acute myeloid leukemia (AML) is a complex disease characterized by a diverse range of recurrent molecular aberrations that occur in many different combinations. Components of transcriptional networks are a common target of these aberrations, leading to network-wide changes and deployment of novel or developmentally inappropriate transcriptional programs. Genome-wide techniques are beginning to reveal the full complexity of normal hematopoietic stem cell transcriptional networks and the extent to which they are deregulated in AML, and new understandings of the mechanisms by which AML cells maintain self-renewal and block differentiation are starting to emerge. The hope is that increased understanding of the network architecture in AML will lead to identification of key oncogenic dependencies that are downstream of multiple network aberrations, and that this knowledge will be translated into new therapies that target these dependencies. Here, we review the current state of knowledge of network perturbation in AML with a focus on major mechanisms of transcription factor dysregulation, including mutation, translocation, and transcriptional dysregulation, and discuss how these perturbations propagate across transcriptional networks. We will also review emerging mechanisms of network disruption, and briefly discuss how increased knowledge of network disruption is already being used to develop new therapies.
Assuntos
Redes Reguladoras de Genes/genética , Leucemia Mieloide Aguda/genética , Transcrição Gênica/genética , Células-Tronco Hematopoéticas/metabolismo , Humanos , Leucemia Mieloide Aguda/metabolismo , Mutação/genética , Fatores de Transcrição/genética , Translocação Genética/genéticaRESUMO
The stem cell leukemia (Scl or Tal1) protein forms part of a multimeric transcription factor complex required for normal megakaryopoiesis. However, unlike other members of this complex such as Gata1, Fli1, and Runx1, mutations of Scl have not been observed as a cause of inherited thrombocytopenia. We postulated that functional redundancy with its closely related family member, lymphoblastic leukemia 1 (Lyl1) might explain this observation. To determine whether Lyl1 can substitute for Scl in megakaryopoiesis, we examined the platelet phenotype of mice lacking 1 or both factors in megakaryocytes. Conditional Scl knockout (KO) mice crossed with transgenic mice expressing Cre recombinase under the control of the mouse platelet factor 4 (Pf4) promoter generated megakaryocytes with markedly reduced but not absent Scl These Pf4Sclc-KO mice had mild thrombocytopenia and subtle defects in platelet aggregation. However, Pf4Sclc-KO mice generated on an Lyl1-null background (double knockout [DKO] mice) had severe macrothrombocytopenia, abnormal megakaryocyte morphology, defective pro-platelet formation, and markedly impaired platelet aggregation. DKO megakaryocytes, but not single-knockout megakaryocytes, had reduced expression of Gata1, Fli1, Nfe2, and many other genes that cause inherited thrombocytopenia. These gene expression changes were significantly associated with shared Scl and Lyl1 E-box binding sites that were also enriched for Gata1, Ets, and Runx1 motifs. Thus, Scl and Lyl1 share functional roles in platelet production by regulating expression of partner proteins including Gata1. We propose that this functional redundancy provides one explanation for the absence of Scl and Lyl1 mutations in inherited thrombocytopenia.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/fisiologia , Plaquetas/fisiologia , Proteínas de Neoplasias/fisiologia , Proteína 1 de Leucemia Linfocítica Aguda de Células T/fisiologia , Trombopoese/genética , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fator de Transcrição GATA1/genética , Fator de Transcrição GATA1/metabolismo , Regulação da Expressão Gênica , Megacariócitos/patologia , Megacariócitos/fisiologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Proteínas de Neoplasias/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Trombocitopenia/sangue , Trombocitopenia/genéticaRESUMO
In patients with a single ventricle, failure of the cardiovascular system may be prevented by substituting the missing sub-pulmonary ventricle with a pump. The aim of this study was to design and evaluate a device for long-term cavopulmonary support. A radial pump with two inlets and two outlets, a single impeller, mechanical bearings, and dual motor configuration was developed. Motor and fluid dynamic components were designed and simulated using computational methods including thermal effects. Hydraulic properties were determined in-vitro with 3D-printed prototypes. The pump design was virtually implanted in an MRI-derived total cavopulmonary connection (TCPC). Computational fluid dynamics (CFD) showed flow fields without regions of flow stagnation (velocity < 0.1â¯m/s) and only minor recirculations within the pump between 2-10â¯L/min against pressure heads of 0-50â¯mmHg at 2500-5000â¯rpm. The computed maximum temperature increase of blood due to motor heat was 1.3â¯K. Virtual implantation studies showed that the pump would introduce an additional volume of approximately 4â¯mL. Experimentally determined hydraulic performance results agreed well with CFD (deviation of <1.3â¯mmHg) and indicated pressure-sensitive characteristics (â¼-2.6â¯mmHg/(L/min)) while balancing the two inlet pressures (∆P < 2.5â¯mmHg) under imbalanced inflow conditions. Through in-silico and in-vitro investigations, we demonstrated a promising pump design, which fulfills the basic requirements for long-term cavopulmonary support.
Assuntos
Técnica de Fontan/instrumentação , Coração Auxiliar , Simulação por Computador , Hemodinâmica , Humanos , Modelos Cardiovasculares , Impressão Tridimensional , Desenho de Prótese/instrumentação , Artéria PulmonarRESUMO
Identification of determinants of fate choices in hematopoietic stem cells (HSCs) is essential to improve the clinical use of HSCs and to enhance our understanding of the biology of normal and malignant hematopoiesis. Here, we show that high-mobility group AT hook 2 (HMGA2), a nonhistone chromosomal-binding protein, is highly and preferentially expressed in HSCs and in the most immature progenitor cell subset of fetal, neonatal, and adult human hematopoiesis. Knockdown of HMGA2 by short hairpin RNA impaired the long-term hematopoietic reconstitution of cord blood (CB)-derived CB CD34+ cells. Conversely, overexpression of HMGA2 in CB CD34+ cells led to overall enhanced reconstitution in serial transplantation assays accompanied by a skewing toward the myeloerythroid lineages. RNA-sequencing analysis showed that enforced HMGA2 expression in CD34+ cells induced gene-expression signatures associated with differentiation toward megakaryocyte-erythroid and myeloid lineages, as well as signatures associated with growth and survival, which at the protein level were coupled with strong activation of AKT. Taken together, our findings demonstrate a key role of HMGA2 in regulation of both proliferation and differentiation of human HSPCs.
Assuntos
Proteína HMGA2/genética , Hematopoese , Células-Tronco Hematopoéticas/citologia , Animais , Proliferação de Células , Células Cultivadas , Células Eritroides/citologia , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/metabolismo , Humanos , Camundongos SCID , Células Mieloides/citologia , Regulação para CimaRESUMO
Despite recent advances in targeted and immune-based therapies, advanced stage melanoma remains a clinical challenge with a poor prognosis. Understanding the genes and cellular processes that drive progression and metastasis is critical for identifying new therapeutic strategies. Here, we found that the GTPase RAB27A was overexpressed in a subset of melanomas, which correlated with poor patient survival. Loss of RAB27A expression in melanoma cell lines inhibited 3D spheroid invasion and cell motility in vitro, and spontaneous metastasis in vivo. The reduced invasion phenotype was rescued by RAB27A-replete exosomes, but not RAB27A-knockdown exosomes, indicating that RAB27A is responsible for the generation of pro-invasive exosomes. Furthermore, while RAB27A loss did not alter the number of exosomes secreted, it did change exosome size and altered the composition and abundance of exosomal proteins, some of which are known to regulate cancer cell movement. Our data suggest that RAB27A promotes the biogenesis of a distinct pro-invasive exosome population. These findings support RAB27A as a key cancer regulator, as well as a potential prognostic marker and therapeutic target in melanoma.
Assuntos
Exossomos/metabolismo , Melanoma/metabolismo , Melanoma/patologia , Proteínas rab27 de Ligação ao GTP/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Meios de Cultivo Condicionados , Exossomos/genética , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Melanoma/genética , Melanoma Experimental/genética , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Melanossomas/genética , Melanossomas/metabolismo , Camundongos , Invasividade Neoplásica , Nevo/genética , Nevo/metabolismo , Proteômica , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Esferoides Celulares , Proteínas rab27 de Ligação ao GTP/biossíntese , Proteínas rab27 de Ligação ao GTP/genéticaRESUMO
Glucocorticoids play a critical role in the treatment of lymphoid malignancies. While glucocorticoid efficacy can be largely attributed to lymphocyte-specific apoptosis, its molecular basis remains elusive. Here, we studied genome-wide lymphocyte-specific open chromatin domains (LSOs), and integrated LSOs with glucocorticoid-induced RNA transcription and chromatin modulation using an in vivo patient-derived xenograft model of acute lymphoblastic leukemia (ALL). This led to the identification of LSOs critical for glucocorticoid-induced apoptosis. Glucocorticoid receptor cooperated with CTCF at these LSOs to mediate DNA looping, which was inhibited by increased DNA methylation in glucocorticoid-resistant ALL and non-lymphoid cell types. Our study demonstrates that lymphocyte-specific epigenetic modifications pre-determine glucocorticoid resistance in ALL and may account for the lack of glucocorticoid sensitivity in other cell types.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Cromatina/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Glucocorticoides/farmacologia , Linfócitos/efeitos dos fármacos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Apoptose/efeitos dos fármacos , Azacitidina/administração & dosagem , Azacitidina/farmacologia , Cromatina/genética , Cromatina/metabolismo , Dexametasona/administração & dosagem , Dexametasona/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Glucocorticoides/administração & dosagem , Humanos , Linfócitos/metabolismo , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismoRESUMO
Purpose:MLH1 is a major tumor suppressor gene involved in the pathogenesis of Lynch syndrome and various sporadic cancers. Despite their potential pathogenic importance, genomic regions capable of regulating MLH1 expression over long distances have yet to be identified.Experimental Design: Here, we use chromosome conformation capture (3C) to screen a 650-kb region flanking the MLH1 locus to identify interactions between the MLH1 promoter and distal regions in MLH1-expressing and nonexpressing cells. Putative enhancers were functionally validated using luciferase reporter assays, chromatin immunoprecipitation, and CRISPR-Cas9-mediated deletion of endogenous regions. To evaluate whether germline variants in the enhancer might contribute to impaired MLH1 expression in patients with suspected Lynch syndrome, we also screened germline DNA from a cohort of 74 patients with no known coding mutations or epimutations at the MLH1 promoter.Results: A 1.8-kb DNA fragment, 35 kb upstream of the MLH1 transcription start site enhances MLH1 gene expression in colorectal cells. The enhancer was bound by CTCF and CRISPR-Cas9-mediated deletion of a core binding region impairs endogenous MLH1 expression. A total of 5.4% of suspected Lynch syndrome patients have a rare single-nucleotide variant (G > A; rs143969848; 2.5% in gnomAD European, non-Finnish) within a highly conserved CTCF-binding motif, which disrupts enhancer activity in SW620 colorectal carcinoma cells.Conclusions: A CTCF-bound region within the MLH1-35 enhancer regulates MLH1 expression in colorectal cells and is worthy of scrutiny in future genetic screening strategies for suspected Lynch syndrome associated with loss of MLH1 expression. Clin Cancer Res; 24(18); 4602-11. ©2018 AACR.