Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 612
Filtrar
2.
Oncogene ; 43(6): 447-456, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38102337

RESUMO

TAL1 is one of the most frequently dysregulated genes in T-ALL and is overexpressed in about 50% of T-ALL cases. One of the molecular mechanisms of TAL1 overexpression is abnormal mutations in the upstream region of the TAL1 promoter that introduce binding motifs for the MYB transcription factor. MYB binding at this location creates a 5' TAL1 super-enhancer (SE), which leads to aberrant expression of TAL1 and is associated with unfavorable clinical outcomes. Although targeting TAL1 is considered to be an attractive therapeutic strategy for patients with T-ALL, direct inhibition of transcription factors is challenging. Here, we show that KLF4, a known tumor suppressor in leukemic cells, suppresses SE-driven TAL1 expression in T-ALL cells. Mechanistically, KLF4 downregulates MYB expression by directly binding to its promoter and inhibits the formation of 5' TAL1 SE. In addition, we found that APTO-253, a small molecule inducer of KLF4, exerts an anti-leukemic effect by targeting SE-driven TAL1 expression in T-ALL cells. Taken together, our results suggest that the induction of KLF4 is a promising strategy to control TAL1 expression and could be a novel treatment for T-ALL patients with a poor prognosis.


Assuntos
Leucemia-Linfoma de Células T do Adulto , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Humanos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Elementos Facilitadores Genéticos , Fatores de Transcrição/genética , Leucemia-Linfoma de Células T do Adulto/genética
3.
Leukemia ; 37(10): 1982-1993, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37591940

RESUMO

TAL1+ T-cell acute lymphoblastic leukemia (T-ALL) is a distinct subtype of leukemia with poor outcomes. Through the cooperation of co-activators, including RUNX1, GATA3, and MYB, the TAL1 oncoprotein extends the immature thymocytes with autonomy and plays an important role in the development of T-ALL. However, this process is not yet well understood. Here, by investigating the transcriptome and prognosis of T-ALL from multiple cohorts, we found that S1PR3 was highly expressed in a subset of TAL1+ T-ALL (S1PR3hi TAL1+ T-ALL), which showed poor outcomes. Through pharmacological and genetic methods, we identified a specific survival-supporting role of S1P-S1PR3 in TAL1+ T-ALL cells. In T-ALL cells, TAL1-RUNX1 up-regulated the expression of S1PR3 by binding to the enhancer region of S1PR3 gene. With hyperactivated S1P-S1PR3, T-ALL cells grew rapidly, partly by activating the KRAS signal. Finally, we assessed S1PR3 inhibitor TY-52156 in T-ALL patient-derived xenografts (PDXs) mouse model. We found that TY-52156 attenuated leukemia progression efficiently and extended the lifespan of S1PR3hi TAL1+ T-ALL xenografts. Our findings demonstrate that S1PR3 plays an important oncogenic role in S1PR3hi TAL1+ T-ALL and may serve as a promising therapeutic target.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Humanos , Animais , Camundongos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo , Timócitos/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética
4.
Leukemia ; 37(10): 1969-1981, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37591943

RESUMO

A hallmark of T-cell acute lymphoblastic leukemia (T-ALL) is the dysregulated expression of oncogenic transcription factors (TFs), including TAL1, NOTCH1 and MYC. Rewiring of the transcriptional program disrupts the tightly controlled spatiotemporal expression of downstream target genes, thereby contributing to leukemogenesis. In this study, we first identify an evolutionarily conserved enhancer element controlling the MYCN oncogene (named enhMYCN) that is aberrantly activated by the TAL1 complex in T-ALL cells. TAL1-positive T-ALL cells are highly dependent on MYCN expression for their maintenance in vitro and in xenograft models. Interestingly, MYCN drives the expression of multiple genes involved in the mevalonate pathway, and T-ALL cells are sensitive to inhibition of HMG-CoA reductase (HMGCR), a rate-limiting enzyme of this pathway. Importantly, MYC and MYCN regulate the same targets and compensate for each other. Thus, MYCN-positive T-ALL cells display a dual dependence on the TAL1-MYCN and NOTCH1-MYC pathways. Together, our results demonstrate that enhMYCN-mediated MYCN expression is required for human T-ALL cells and implicate the TAL1-MYCN-HMGCR axis as a potential therapeutic target in T-ALL.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Humanos , Proteína Proto-Oncogênica N-Myc/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Ácido Mevalônico , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo , Linfócitos T/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo
6.
PLoS Biol ; 21(6): e3002175, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37379322

RESUMO

T-cell acute lymphoblastic leukemia (T-ALL) protein 1 (TAL1) is a central transcription factor in hematopoiesis. The timing and level of TAL1 expression orchestrate the differentiation to specialized blood cells and its overexpression is a common cause of T-ALL. Here, we studied the 2 protein isoforms of TAL1, short and long, which are generated by the use of alternative promoters as well as by alternative splicing. We analyzed the expression of each isoform by deleting an enhancer or insulator, or by opening chromatin at the enhancer location. Our results show that each enhancer promotes expression from a specific TAL1 promoter. Expression from a specific promoter gives rise to a unique 5' UTR with differential regulation of translation. Moreover, our study suggests that the enhancers regulate TAL1 exon 3 alternative splicing by inducing changes in the chromatin at the splice site, which we demonstrate is mediated by KMT2B. Furthermore, our results indicate that TAL1-short binds more strongly to TAL1 E-protein partners and functions as a stronger transcription factor than TAL1-long. Specifically TAL1-short has a unique transcription signature promoting apoptosis. Finally, when we expressed both isoforms in mice bone marrow, we found that while overexpression of both isoforms prevents lymphoid differentiation, expression of TAL1-short alone leads to hematopoietic stem cell exhaustion. Furthermore, we found that TAL1-short promoted erythropoiesis and reduced cell survival in the CML cell line K562. While TAL1 and its partners are considered promising therapeutic targets in the treatment of T-ALL, our results show that TAL1-short could act as a tumor suppressor and suggest that altering TAL1 isoform's ratio could be a preferred therapeutic approach.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Animais , Camundongos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Cromatina , Hematopoese/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/patologia , Isoformas de Proteínas/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Fatores de Transcrição/metabolismo
7.
Zhonghua Xue Ye Xue Za Zhi ; 44(2): 132-136, 2023 Feb 14.
Artigo em Chinês | MEDLINE | ID: mdl-36948867

RESUMO

Objective: To assess the clinical characteristics and prognosis of patients with SIL-TAL1-positive T-cell acute lymphoblastic leukemia (T-ALL) . Methods: The clinical data of 19 SIL-TAL1-positive T-ALL patients admitted to the First Affiliated Hospital of Soochow University between January 2014 and February 2022 were retrospectively computed and contrasted with SIL-TAL1-negative T-ALL patients. Results: The median age of the 19 SIL-TAL1-positive T-ALL patients was 15 (7 to 41 years) , including 16 males (84.2%) . SIL-TAL1-positive T-ALL patients had younger age, higher WBC, and hemoglobin compared with SIL-TAL1-negative T-ALL patients. There was no discrepancy in gender distribution, PLT, chromosome abnormality distribution, immunophenotyping, and complete remission (CR) rate. The 3-year overall survival (OS) was 60.9% and 74.4%, respectively (HR=2.070, P=0.071) . The 3-year relapse-free survival (RFS) was 49.2% and 70.6%, respectively (HR=2.275, P=0.040) . The 3-year RFS rate of SIL-TAL1-positive T-ALL patients was considerably lower than SIL-TAL1-negative T-ALL patients. Conclusion: SIL-TAL1-positive T-ALL patients were connected to younger age, higher WBC, higher HGB, and poor outcome.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Adolescente , Adulto , Humanos , Masculino , Adulto Jovem , Aberrações Cromossômicas , Proteínas de Fusão Oncogênica/genética , Prognóstico , Recidiva , Estudos Retrospectivos , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Linfócitos T , Feminino , Criança
8.
FASEB J ; 37(4): e22870, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36929052

RESUMO

Enhancers activate gene transcription remotely, which requires tissue specific transcription factors binding to them. GATA1 and TAL1 are hematopoietic/erythroid-specific factors and often bind together to enhancers, activating target genes. Interestingly, we found that some hematopoietic/erythroid genes are transcribed in a GATA1-dependent but TAL1-independnet manner. They appear to have enhancers within a relatively short distance. In this study, we paired highly transcribed hematopoietic/erythroid genes with the nearest GATA1/TAL1-binding enhancers and analyzed these putative enhancer-gene pairs depending on distance between them. Enhancers located at various distances from genes in the pairs, which was not related to transcription level of the genes. However, genes with enhancers at short distances away tended to be transcriptionally unaffected by TAL1 depletion. Histone H3K27ac extended from the enhancers to target genes. The H3K27ac extension was maintained without TAL1, even though it disappeared owing to the loss of GATA1. Intergenic RNA was highly transcribed from the enhancers to nearby target genes, independent of TAL1. Taken together, TAL1-independent transcription of hematopoietic/erythroid genes appears to be promoted by enhancers present in a short distance. These enhancers are likely to activate nearby target genes by tracking the intervening regions.


Assuntos
DNA Intergênico , Elementos Facilitadores Genéticos , Hematopoese , Histonas , DNA Intergênico/genética , DNA Intergênico/metabolismo , Hematopoese/genética , Histonas/genética , Histonas/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA/metabolismo , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo
9.
Mol Cancer ; 22(1): 12, 2023 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-36650499

RESUMO

The acquisition of genetic abnormalities engendering oncogene dysregulation underpins cancer development. Certain proto-oncogenes possess several dysregulation mechanisms, yet how each mechanism impacts clinical outcome is unclear. Using T-cell acute lymphoblastic leukemia (T-ALL) as an example, we show that patients harboring 5'super-enhancer (5'SE) mutations of the TAL1 oncogene identifies a specific patient subgroup with poor prognosis irrespective of the level of oncogene dysregulation. Remarkably, the MYB dependent oncogenic 5'SE can be targeted using Mebendazole to induce MYB protein degradation and T-ALL cell death. Of note Mebendazole treatment demonstrated efficacy in vivo in T-ALL preclinical models. Our work provides proof of concept that within a specific oncogene driven cancer, the mechanism of oncogene dysregulation rather than the oncogene itself can identify clinically distinct patient subgroups and pave the way for future super-enhancer targeting therapy.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Humanos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Mebendazol
10.
Haematologica ; 108(5): 1259-1271, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36632736

RESUMO

T-cell acute lymphocytic leukemia protein 1 (TAL1) is one of the most frequently deregulated oncogenes in T-cell acute lymphoblastic leukemia (T-ALL). Its deregulation can occur through diverse cis-alterations, including SIL-TAL1 microdeletions, translocations with T-cell Receptor loci, and more recently described upstream intergenic non-coding mutations. These mutations consist of recurrent focal microinsertions that create an oncogenic neo-enhancer accompanied by activating epigenetic marks. This observation laid the groundwork for an innovative paradigm concerning the activation of proto-oncogenes via genomic alterations of non-coding intergenic regions. However, for the majority of T-ALL expressing TAL1 (TAL1+), the deregulation mechanism remains 'unresolved'. We took advantage of H3K27ac and H3K4me3 chromatin immunoprecipitation sequencing data of eight cases of T-ALL, including five TAL1+ cases. We identified a putative novel oncogenic neo-enhancer downstream of TAL1 in an unresolved monoallelic TAL1+ case. A rare but recurrent somatic heterozygous microinsertion within this region creates a de novo binding site for MYB transcription factor. Here we demonstrate that this mutation leads to increased enhancer activity, gain of active epigenetic marks, and TAL1 activation via recruitment of MYB. These results highlight the diversity of non-coding mutations that can drive oncogene activation.


Assuntos
Elementos Facilitadores Genéticos , Leucemia-Linfoma Linfoblástico de Células T Precursoras , Proteína 1 de Leucemia Linfocítica Aguda de Células T , Humanos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Mutação , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Linfócitos T/metabolismo , Fatores de Transcrição/genética
11.
Haematologica ; 108(2): 367-381, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-36073513

RESUMO

T-cell acute lymphoblastic leukemia (T-ALL) is a malignancy of thymic T-cell precursors. Overexpression of oncogenic transcription factor TAL1 is observed in 40-60% of human T-ALL cases, frequently together with activation of the NOTCH1 and PI3K-AKT pathways. In this study, we performed chemical screening to identify small molecules that can inhibit the enhancer activity driven by TAL1 using the GIMAP enhancer reporter system. Among approximately 3,000 compounds, PIK- 75, a known inhibitor of PI3K and CDK, was found to strongly inhibit the enhancer activity. Mechanistic analysis demonstrated that PIK-75 blocks transcriptional activity, which primarily affects TAL1 target genes as well as AKT activity. TAL1-positive, AKT-activated T-ALL cells were very sensitive to PIK-75, as evidenced by growth inhibition and apoptosis induction, while T-ALL cells that exhibited activation of the JAK-STAT pathway were insensitive to this drug. Together, our study demonstrates a strategy targeting two types of core machineries mediated by oncogenic transcription factors and signaling pathways in T-ALL.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Humanos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo , Janus Quinases/metabolismo , Transdução de Sinais , Fatores de Transcrição STAT/metabolismo , Fatores de Transcrição/genética , Linfócitos T/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo
13.
Sci Rep ; 12(1): 16974, 2022 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-36217016

RESUMO

Progress in the generation of Hematopoietic Stem and Progenitor Cells (HSPCs) in vitro and ex vivo has been built on the knowledge of developmental hematopoiesis, underscoring the importance of understanding this process. HSPCs emerge within the embryonic vasculature through an Endothelial-to-Hematopoietic Transition (EHT). The transcriptional regulator Tal1 exerts essential functions in the earliest stages of blood development, but is considered dispensable for the EHT. Nevertheless, Tal1 is expressed with its binding partner Lmo2 and it homologous Lyl1 in endothelial and transitioning cells at the time of EHT. Here, we investigated the function of these genes using a mouse embryonic-stem cell (mESC)-based differentiation system to model hematopoietic development. We showed for the first time that the expression of TAL1 in endothelial cells is crucial to ensure the efficiency of the EHT process and a sustained hematopoietic output. Our findings uncover an important function of Tal1 during the EHT, thus filling the current gap in the knowledge of the role of this master gene throughout the whole process of hematopoietic development.


Assuntos
Células Endoteliais , Hematopoese , Animais , Diferenciação Celular/genética , Células Endoteliais/metabolismo , Endotélio , Hematopoese/genética , Células-Tronco Hematopoéticas/metabolismo , Camundongos , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo
14.
Sci Rep ; 12(1): 7226, 2022 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-35508511

RESUMO

The transcription factor complex, consisting of LMO2, TAL1 or LYL1, and GATA2, plays an important role in capillary sprouting by regulating VEGFR2, DLL4, and angiopoietin 2 in tip cells. Overexpression of the basic helix-loop-helix transcription factor LYL1 in transgenic mice results in shortened tails. This phenotype is associated with vessel hyperbranching and a relative paucity of straight vessels due to DLL4 downregulation in tip cells by forming aberrant complex consisting of LMO2 and LYL1. Knockdown of LMO2 or TAL1 inhibits capillary sprouting in spheroid-based angiogenesis assays, which is associated with decreased angiopoietin 2 secretion. In the same assay using mixed TAL1- and LYL1-expressing endothelial cells, TAL1 was found to be primarily located in tip cells, while LYL1-expressing cells tended to occupy the stalk position in sprouts by upregulating VEGFR1 than TAL1. Thus, the interaction between LMO2 and TAL1 in tip cells plays a key role in angiogenic switch of sprouting angiogenesis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Angiopoietina-2 , Proteínas com Domínio LIM/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Células Endoteliais , Proteínas com Domínio LIM/genética , Camundongos , Proteínas de Neoplasias/genética , Neovascularização Fisiológica/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética
15.
Int J Mol Sci ; 23(9)2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35563322

RESUMO

The B-cell CLL/lymphoma 11B gene (BCL11B) plays a crucial role in T-cell development, but its role in T-cell malignancies is still unclear. To study its role in the development of T-cell neoplasms, we generated an inducible BCL11B knockout in a murine T cell leukemia/lymphoma model. Mice, bearing human oncogenes TAL BHLH Transcription Factor 1 (TAL1; SCL) or LIM Domain Only 1 (LMO1), responsible for T-cell acute lymphoblastic leukemia (T-ALL) development, were crossed with BCL11B floxed and with CRE-ER/lox mice. The mice with a single oncogene BCL11Bflox/floxCREtg/tgTAL1tg or BCL11Bflox/floxCREtg/tgLMO1tg were healthy, bred normally, and were used to maintain the mice in culture. When crossed with each other, >90% of the double transgenic mice BCL11Bflox/floxCREtg/tgTAL1tgLMO1tg, within 3 to 6 months after birth, spontaneously developed T-cell leukemia/lymphoma. Upon administration of synthetic estrogen (tamoxifen), which binds to the estrogen receptor and activates the Cre recombinase, the BCL11B gene was knocked out by excision of its fourth exon from the genome. The mouse model of inducible BCL11B knockout we generated can be used to study the role of this gene in cancer development and the potential therapeutic effect of BCL11B inhibition in T-cell leukemia and lymphoma.


Assuntos
Leucemia de Células T , Fatores de Transcrição , Animais , Modelos Animais de Doenças , Proteínas com Domínio LIM/genética , Leucemia de Células T/genética , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Proteínas Nucleares/genética , Proteínas Repressoras/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/genética
16.
Phytomedicine ; 102: 154150, 2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35569185

RESUMO

BACKGROUND: Thrombocytopenia (TP) remains a challenge in clinical hematology. TP may have serious consequences, such as recurrent skin and mucosal bleeding and increased risk of intracranial and internal organ hemorrhage. However, effective and safe therapeutic drugs for the long-term management of TP are still lacking. PURPOSE: This study aimed to identify more effective active compounds for TP therapy. METHODS: Liquid chromatography-mass spectrometry-nuclear magnetic resonance analysis was used to confirm the medicinal species and chemical structure of Hirsutine (HS). The proliferation of HS was examined by Cell Counting Kit (CCK-8) assay on cells lines. The effect of HS on megakaryocyte differentiation was analyzed by evaluating the expression of CD41, CD42b, and DNA ploidy via flow cytometry (FCM). The morphology of megakaryocytes and intermediate cells was observed using an optical microscope. K562 cells were then stained with Giemsa and benzidine. qRT-PCR was used to examine the mRNA expression of GATA-1, GATA-2, FOG-1, TAL-1, RUNX-1, NF-E2, and KLF-1 in K562 cells. Protein levels of the transcription factors were analyzed by western blotting. An MEK inhibitor was used to verify the relationship between the MEK/ERK signaling pathway and CD41/CD42b (FCM), FOG-1, and TAL-1. The Kunming thrombocytopenia mouse model was established by X-ray irradiation (4 Gy) and used to test HS activity and related hematopoietic organ index in vivo. Finally, computer simulations of molecular docking were used to predict the binding energies between HS-MEK and HS-ERK. RESULTS: We preliminarily identified HS by screening a plant-sourced compound library for natural compounds with megakaryocytic differentiation and maturation (MKD/MKM)-promoting activity. We found that HS not only enhanced MKD/MKM of K562 and Meg01 cells, but also suppressed the decline of peripheral platelet levels in X-ray-induced myelosuppressive mice. In addition, HS promoted MKD via activation of MEK-ERK-FOG1/TAL1 signaling, which may be the key molecular mechanism of HS action in TP treatment. Molecular docking simulations further verified that HS targets the signaling protein MEK with high-affinity. CONCLUSION: In this study, we report for the first time that hirsutine boosts MKD/MKM through the MEK/ERK/FOG1/TAL1 signaling pathway and thus represents a promising treatment option for TP.


Assuntos
Trombocitopenia , Trombopoese , Alcaloides , Animais , Diferenciação Celular , Humanos , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Simulação de Acoplamento Molecular , Transdução de Sinais , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo , Fatores de Transcrição/metabolismo
17.
Front Immunol ; 13: 867443, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35401501

RESUMO

Early T-cell development is precisely controlled by E proteins, that indistinguishably include HEB/TCF12 and E2A/TCF3 transcription factors, together with NOTCH1 and pre-T cell receptor (TCR) signalling. Importantly, perturbations of early T-cell regulatory networks are implicated in leukemogenesis. NOTCH1 gain of function mutations invariably lead to T-cell acute lymphoblastic leukemia (T-ALL), whereas inhibition of E proteins accelerates leukemogenesis. Thus, NOTCH1, pre-TCR, E2A and HEB functions are intertwined, but how these pathways contribute individually or synergistically to leukemogenesis remain to be documented. To directly address these questions, we leveraged Cd3e-deficient mice in which pre-TCR signaling and progression through ß-selection is abrogated to dissect and decouple the roles of pre-TCR, NOTCH1, E2A and HEB in SCL/TAL1-induced T-ALL, via the use of Notch1 gain of function transgenic (Notch1ICtg) and Tcf12+/- or Tcf3+/- heterozygote mice. As a result, we now provide evidence that both HEB and E2A restrain cell proliferation at the ß-selection checkpoint while the clonal expansion of SCL-LMO1-induced pre-leukemic stem cells in T-ALL is uniquely dependent on Tcf12 gene dosage. At the molecular level, HEB protein levels are decreased via proteasomal degradation at the leukemic stage, pointing to a reversible loss of function mechanism. Moreover, in SCL-LMO1-induced T-ALL, loss of one Tcf12 allele is sufficient to bypass pre-TCR signaling which is required for Notch1 gain of function mutations and for progression to T-ALL. In contrast, Tcf12 monoallelic deletion does not accelerate Notch1IC-induced T-ALL, indicating that Tcf12 and Notch1 operate in the same pathway. Finally, we identify a tumor suppressor gene set downstream of HEB, exhibiting significantly lower expression levels in pediatric T-ALL compared to B-ALL and brain cancer samples, the three most frequent pediatric cancers. In summary, our results indicate a tumor suppressor function of HEB/TCF12 in T-ALL to mitigate cell proliferation controlled by NOTCH1 in pre-leukemic stem cells and prevent NOTCH1-driven progression to T-ALL.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Humanos , Camundongos , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Proteínas Proto-Oncogênicas/metabolismo , Receptor Notch1/genética , Receptor Notch1/metabolismo , Receptores de Antígenos de Linfócitos T , Proteína 1 de Leucemia Linfocítica Aguda de Células T , Linfócitos T/metabolismo , Fatores de Transcrição/metabolismo
18.
Haematologica ; 107(10): 2304-2317, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35354248

RESUMO

TAL1 is ectopically expressed in about 30% of T-cell acute lymphoblastic leukemia (T-ALL) due to chromosomal rearrangements leading to the STIL-TAL1 fusion genes or due to non-coding mutations leading to a de novo enhancer driving TAL1 expression. Analysis of sequence data from T-ALL cases demonstrates a significant association between TAL1 expression and activating mutations of the PI3K-AKT pathway. We investigated the oncogenic function of TAL1 and the possible cooperation with PI3K-AKT pathway activation using isogenic pro-T-cell cultures ex vivo and in vivo leukemia models. We found that TAL1 on its own suppressed T-cell growth, in part by affecting apoptosis genes, while the combination with AKT pathway activation reduced apoptosis and was strongly driving cell proliferation ex vivo and leukemia development in vivo. As a consequence, we found that TAL1+AKTE17K transformed cells are more sensitive to PI3K-AKT pathway inhibition compared to AKTE17K transformed cells, related to the negative effect of TAL1 in the absence of activated PI3K-AKT signaling. We also found that both TAL1 and PI3K-AKT signaling increased the DNA-repair signature in T cells resulting in synergy between PARP and PI3K-AKT pathway inhibition. In conclusion, we have developed a novel mouse model for TAL1+AKTE17K driven T-ALL development and have identified a vulnerability of these leukemia cells to PI3K-AKT and PARP inhibitors.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Animais , DNA , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo , Linfócitos T/metabolismo
19.
Int J Mol Sci ; 22(15)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34360789

RESUMO

The erythroid Krüppel-like factor EKLF/KLF1 is a hematopoietic transcription factor binding to the CACCC DNA motif and participating in the regulation of erythroid differentiation. With combined use of microarray-based gene expression profiling and the promoter-based ChIP-chip assay of E14.5 fetal liver cells from wild type (WT) and EKLF-knockout (Eklf-/-) mouse embryos, we identified the pathways and direct target genes activated or repressed by EKLF. This genome-wide study together with the molecular/cellular analysis of the mouse erythroleukemic cells (MEL) indicate that among the downstream direct target genes of EKLF is Tal1/Scl. Tal1/Scl encodes another DNA-binding hematopoietic transcription factor TAL1/SCL, known to be an Eklf activator and essential for definitive erythroid differentiation. Further identification of the authentic Tal gene promoter in combination with the in vivo genomic footprinting approach and DNA reporter assay demonstrate that EKLF activates the Tal gene through binding to a specific CACCC motif located in its promoter. These data establish the existence of a previously unknow positive regulatory feedback loop between two DNA-binding hematopoietic transcription factors, which sustains mammalian erythropoiesis.


Assuntos
Eritropoese , Feto/embriologia , Hematopoese Extramedular , Fatores de Transcrição Kruppel-Like/metabolismo , Fígado/embriologia , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo , Animais , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Camundongos Knockout , Elementos de Resposta , Proteína 1 de Leucemia Linfocítica Aguda de Células T/genética
20.
J Mol Med (Berl) ; 99(10): 1447-1458, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34223928

RESUMO

The NF-κB signaling pathway is an important downstream pathway of oncogenic Notch1 in T cell acute lymphoblastic leukemia (T-ALL) cells. However, the molecular mechanisms underlying the cascade activation of Notch1 in T-ALL cells are poorly understood. Here, we evaluated the role of CARMA1 in Notch1-induced NF-κB activation in T-ALL cells. CARMA1 was highly and specifically expressed in T-ALL cells and correlated with the prognosis of T-ALL patients. Interestingly, CARMA1 knockdown only inhibited the growth and proliferation of SIL-TAL1 fusion gene-negative T-ALL cells. In addition, CARMA1 knockdown arrested T-ALL cells at the G1 phase. Furthermore, CARMA1 knockdown significantly inhibited the proliferation of T-ALL cells in vivo and prolonged the survival of mice. Mechanistically, CARMA1 deficiency abolished Notch1-induced NF-κB transcriptional activation and significantly reduced expression levels of the NF-κB target genes c-Myc, Bcl-2, and CCR7. Taken together, these results of our study identify CARMA1 as one of the crucial mediators of Notch1-induced transformation of T-All cells, suggesting that CARMA1 is a promising therapeutic target for T-ALL due to its specific expression in lymphocytes. KEY MESSAGES: CARMA1 contributes to cell survival only in SIL-TAL1 negative T-ALL cells. CARMA1 is a crucial mediator of Notch1-induced activation of NF-κB pathway. CARMA1 is a promising therapeutic target for T-ALL.


Assuntos
Proteínas Adaptadoras de Sinalização CARD/metabolismo , Guanilato Ciclase/metabolismo , NF-kappa B/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Receptor Notch1/metabolismo , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Células Jurkat , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Transdução de Sinais/fisiologia , Proteína 1 de Leucemia Linfocítica Aguda de Células T/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...