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1.
Nature ; 628(8007): 442-449, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38538798

RESUMO

Whereas oncogenes can potentially be inhibited with small molecules, the loss of tumour suppressors is more common and is problematic because the tumour-suppressor proteins are no longer present to be targeted. Notable examples include SMARCB1-mutant cancers, which are highly lethal malignancies driven by the inactivation of a subunit of SWI/SNF (also known as BAF) chromatin-remodelling complexes. Here, to generate mechanistic insights into the consequences of SMARCB1 mutation and to identify vulnerabilities, we contributed 14 SMARCB1-mutant cell lines to a near genome-wide CRISPR screen as part of the Cancer Dependency Map Project1-3. We report that the little-studied gene DDB1-CUL4-associated factor 5 (DCAF5) is required for the survival of SMARCB1-mutant cancers. We show that DCAF5 has a quality-control function for SWI/SNF complexes and promotes the degradation of incompletely assembled SWI/SNF complexes in the absence of SMARCB1. After depletion of DCAF5, SMARCB1-deficient SWI/SNF complexes reaccumulate, bind to target loci and restore SWI/SNF-mediated gene expression to levels that are sufficient to reverse the cancer state, including in vivo. Consequently, cancer results not from the loss of SMARCB1 function per se, but rather from DCAF5-mediated degradation of SWI/SNF complexes. These data indicate that therapeutic targeting of ubiquitin-mediated quality-control factors may effectively reverse the malignant state of some cancers driven by disruption of tumour suppressor complexes.


Assuntos
Complexos Multiproteicos , Mutação , Neoplasias , Proteína SMARCB1 , Animais , Feminino , Humanos , Masculino , Camundongos , Linhagem Celular Tumoral , Sistemas CRISPR-Cas , Edição de Genes , Neoplasias/genética , Neoplasias/metabolismo , Proteína SMARCB1/deficiência , Proteína SMARCB1/genética , Proteína SMARCB1/metabolismo , Proteínas Supressoras de Tumor/deficiência , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Complexos Multiproteicos/química , Complexos Multiproteicos/metabolismo , Proteólise , Ubiquitina/metabolismo
2.
Blood ; 143(7): 619-630, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-37890156

RESUMO

ABSTRACT: UBTF tandem duplications (UBTF-TDs) have recently emerged as a recurrent alteration in pediatric and adult acute myeloid leukemia (AML). UBTF-TD leukemias are characterized by a poor response to conventional chemotherapy and a transcriptional signature that mirrors NUP98-rearranged and NPM1-mutant AMLs, including HOX-gene dysregulation. However, the mechanism by which UBTF-TD drives leukemogenesis remains unknown. In this study, we investigated the genomic occupancy of UBTF-TD in transformed cord blood CD34+ cells and patient-derived xenograft models. We found that UBTF-TD protein maintained genomic occupancy at ribosomal DNA loci while also occupying genomic targets commonly dysregulated in UBTF-TD myeloid malignancies, such as the HOXA/HOXB gene clusters and MEIS1. These data suggest that UBTF-TD is a gain-of-function alteration that results in mislocalization to genomic loci dysregulated in UBTF-TD leukemias. UBTF-TD also co-occupies key genomic loci with KMT2A and menin, which are known to be key partners involved in HOX-dysregulated leukemias. Using a protein degradation system, we showed that stemness, proliferation, and transcriptional signatures are dependent on sustained UBTF-TD localization to chromatin. Finally, we demonstrate that primary cells from UBTF-TD leukemias are sensitive to the menin inhibitor SNDX-5613, resulting in markedly reduced in vitro and in vivo tumor growth, myeloid differentiation, and abrogation of the UBTF-TD leukemic expression signature. These findings provide a viable therapeutic strategy for patients with this high-risk AML subtype.


Assuntos
Proteínas de Homeodomínio , Leucemia Mieloide Aguda , Humanos , Criança , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Fatores de Transcrição , Proteína Meis1/genética
3.
Proc Natl Acad Sci U S A ; 120(16): e2220134120, 2023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-37036970

RESUMO

Bromo- and extra-terminal domain inhibitors (BETi) have exhibited therapeutic activities in many cancers. However, the mechanisms controlling BETi response and resistance are not well understood. We conducted genome-wide loss-of-function CRISPR screens using BETi-treated KMT2A-rearranged (KMT2A-r) cell lines. We revealed that Speckle-type POZ protein (SPOP) gene (Speckle Type BTB/POZ Protein) deficiency caused significant BETi resistance, which was further validated in cell lines and xenograft models. Proteomics analysis and a kinase-vulnerability CRISPR screen indicated that cells treated with BETi are sensitive to GSK3 perturbation. Pharmaceutical inhibition of GSK3 reversed the BETi-resistance phenotype. Based on this observation, a combination therapy regimen inhibiting both BET and GSK3 was developed to impede KMT2A-r leukemia progression in patient-derived xenografts in vivo. Our results revealed molecular mechanisms underlying BETi resistance and a promising combination treatment regimen of ABBV-744 and CHIR-98014 by utilizing unique ex vivo and in vivo KMT2A-r PDX models.


Assuntos
Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Leucemia , Humanos , Quinase 3 da Glicogênio Sintase/metabolismo , Linhagem Celular Tumoral , Leucemia/tratamento farmacológico , Leucemia/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Repressoras/metabolismo
5.
J Pathol ; 257(5): 579-592, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35342947

RESUMO

Mesenchymal chondrosarcoma is a rare, high-grade, primitive mesenchymal tumor. It accounts for around 2-10% of all chondrosarcomas and mainly affects adolescents and young adults. We previously described the HEY1-NCOA2 as a recurrent gene fusion in mesenchymal chondrosarcoma, an important breakthrough for characterizing this disease; however, little study had been done to characterize the fusion protein functionally, in large part due to a lack of suitable models for evaluating the impact of HEY1-NCOA2 expression in the appropriate cellular context. We used iPSC-derived mesenchymal stem cells (iPSC-MSCs), which can differentiate into chondrocytes, and generated stable transduced iPSC-MSCs with inducible expression of HEY1-NCOA2 fusion protein, wildtype HEY1 or wildtype NCOA2. We next comprehensively analyzed both the DNA binding properties and transcriptional impact of HEY1-NCOA2 expression by integrating genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) and expression profiling (RNA-seq). We demonstrated that HEY1-NCOA2 fusion protein preferentially binds to promoter regions of canonical HEY1 targets, resulting in transactivation of HEY1 targets, and significantly enhances cell proliferation. Intriguingly, we identified that both PDGFB and PDGFRA were directly targeted and upregulated by HEY1-NCOA2; and the fusion protein, but not wildtype HEY1 or NCOA2, dramatically increased the level of phospho-AKT (Ser473). Our findings provide a rationale for exploring PDGF/PI3K/AKT inhibition in treating mesenchymal chondrosarcoma. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.


Assuntos
Neoplasias Ósseas , Condrossarcoma Mesenquimal , Adolescente , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Carcinogênese , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Transformação Celular Neoplásica , Condrossarcoma Mesenquimal/genética , Condrossarcoma Mesenquimal/metabolismo , Condrossarcoma Mesenquimal/patologia , Fusão Gênica , Genômica , Humanos , Coativador 2 de Receptor Nuclear/genética , Coativador 2 de Receptor Nuclear/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Adulto Jovem
6.
Nucleic Acids Res ; 46(D1): D186-D193, 2018 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-29069459

RESUMO

Gene overlap plays various regulatory functions on transcriptional and post-transcriptional levels. Most current studies focus on protein-coding genes overlapping with non-protein-coding counterparts, the so called natural antisense transcripts. Considerably less is known about the role of gene overlap in the case of two protein-coding genes. Here, we provide OverGeneDB, a database of human and mouse 5' end protein-coding overlapping genes. The database contains 582 human and 113 mouse gene pairs that are transcribed using overlapping promoters in at least one analyzed library. Gene pairs were identified based on the analysis of the transcription start site (TSS) coordinates in 73 human and 10 mouse organs, tissues and cell lines. Beside TSS data, resources for 26 human lung adenocarcinoma cell lines also contain RNA-Seq and ChIP-Seq data for seven histone modifications and RNA Polymerase II activity. The collected data revealed that the overlap region is rarely conserved between the studied species and tissues. In ∼50% of the overlapping genes, transcription started explicitly in the overlap regions. In the remaining half of overlapping genes, transcription was initiated both from overlapping and non-overlapping TSSs. OverGeneDB is accessible at http://overgenedb.amu.edu.pl.


Assuntos
Bases de Dados Genéticas , Homologia de Genes , Animais , Expressão Gênica , Código das Histonas , Humanos , Camundongos , Família Multigênica , Fases de Leitura Aberta , Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo , Análise de Sequência de RNA , Fatores de Transcrição/metabolismo , Sítio de Iniciação de Transcrição
7.
PLoS Genet ; 11(10): e1005579, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26474060

RESUMO

Gene retroposition leads to considerable genetic variation between individuals. Recent studies revealed the presence of at least 208 retroduplication variations (RDVs), a class of polymorphisms, in which a retrocopy is present or absent from individual genomes. Most of these RDVs resulted from recent retroduplications. In this study, we used the results of Phase 1 from the 1000 Genomes Project to investigate the variation in loss of ancestral (i.e. shared with other primates) retrocopies among different human populations. In addition, we examined retrocopy expression levels using RNA-Seq data derived from the Ilumina BodyMap project, as well as data from lymphoblastoid cell lines provided by the Geuvadis Consortium. We also developed a new approach to detect novel retrocopies absent from the reference human genome. We experimentally confirmed the existence of the detected retrocopies and determined their presence or absence in the human genomes of 17 different populations. Altogether, we were able to detect 193 RDVs; the majority resulted from retrocopy deletion. Most of these RDVs had not been previously reported. We experimentally confirmed the expression of 11 ancestral retrogenes that underwent deletion in certain individuals. The frequency of their deletion, with the exception of one retrogene, is very low. The expression, conservation and low rate of deletion of the remaining 10 retrocopies may suggest some functionality. Aside from the presence or absence of expressed retrocopies, we also searched for differences in retrocopy expression levels between populations, finding 9 retrogenes that undergo statistically significant differential expression.


Assuntos
Evolução Molecular , Duplicação Gênica , Genoma Humano , Polimorfismo Genético , Animais , Regulação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Projeto Genoma Humano , Humanos , Primatas/genética
8.
Plant Cell Physiol ; 57(1): e8, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26657895

RESUMO

Long non-coding RNAs (lncRNAs) represent a class of potent regulators of gene expression that are found in a wide array of eukaryotes; however, our knowledge about these molecules in plants is still very limited. In particular, a number of model plant species still lack comprehensive data sets of lncRNAs and their annotations, and very little is known about their biological roles. To meet these shortcomings, we created an online database of lncRNAs in 10 model plant species. The lncRNAs were identified computationally using dozens of publicly available RNA sequencing (RNA-Seq) libraries. Expression values, coding potential, sequence alignments as well as other types of data provide annotation for the identified lncRNAs. In order to better characterize them, we investigated their potential roles in splicing modulation and deregulation of microRNA functions. The data are freely available for searching, browsing and downloading from an online database called CANTATAdb (http://cantata.amu.edu.pl, http://yeti.amu.edu.pl/CANTATA/).


Assuntos
Bases de Dados de Ácidos Nucleicos , Regulação da Expressão Gênica de Plantas , MicroRNAs/genética , Plantas/genética , RNA Longo não Codificante/genética , Internet , RNA de Plantas/genética , Análise de Sequência de RNA , Interface Usuário-Computador
9.
Mol Biol Evol ; 30(2): 384-96, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23066043

RESUMO

Gene duplicates generated via retroposition were long thought to be pseudogenized and consequently decayed. However, a significant number of these genes escaped their evolutionary destiny and evolved into functional genes. Despite multiple studies, the number of functional retrogenes in human and other genomes remains unclear. We performed a comparative analysis of human, chicken, and worm genomes to identify "orphan" retrogenes, that is, retrogenes that have replaced their progenitors. We located 25 such candidates in the human genome. All of these genes were previously known, and the majority has been intensively studied. Despite this, they have never been recognized as retrogenes. Analysis revealed that the phenomenon of replacing parental genes with their retrocopies has been taking place over the entire span of animal evolution. This process was often species specific and contributed to interspecies differences. Surprisingly, these retrogenes, which should evolve in a more relaxed mode, are subject to a very strong purifying selection, which is, on average, two and a half times stronger than other human genes. Also, for retrogenes, they do not show a typical overall tendency for a testis-specific expression. Notably, seven of them are associated with human diseases. Recognizing them as "orphan" retrocopies, which have different regulatory machinery than their parents, is important for any disease studies in model organisms, especially when discoveries made in one species are transferred to humans.


Assuntos
Genoma Humano , Retroelementos , Sequência de Aminoácidos , Animais , Análise por Conglomerados , Complexos Endossomais de Distribuição Requeridos para Transporte/química , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Duplicação Gênica , Perfilação da Expressão Gênica , Ordem dos Genes , Estudos de Associação Genética , Humanos , Masculino , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , Dados de Sequência Molecular , Paraplegia/genética , Filogenia , Pseudogenes , Alinhamento de Sequência
10.
Syst Biol ; 62(6): 901-12, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23925510

RESUMO

Gene trees record the combination of gene-level events, such as duplication, transfer and loss (DTL), and species-level events, such as speciation and extinction. Gene tree-species tree reconciliation methods model these processes by drawing gene trees into the species tree using a series of gene and species-level events. The reconstruction of gene trees based on sequence alone almost always involves choosing between statistically equivalent or weakly distinguishable relationships that could be much better resolved based on a putative species tree. To exploit this potential for accurate reconstruction of gene trees, the space of reconciled gene trees must be explored according to a joint model of sequence evolution and gene tree-species tree reconciliation. Here we present amalgamated likelihood estimation (ALE), a probabilistic approach to exhaustively explore all reconciled gene trees that can be amalgamated as a combination of clades observed in a sample of gene trees. We implement the ALE approach in the context of a reconciliation model (Szöllosi et al. 2013), which allows for the DTL of genes. We use ALE to efficiently approximate the sum of the joint likelihood over amalgamations and to find the reconciled gene tree that maximizes the joint likelihood among all such trees. We demonstrate using simulations that gene trees reconstructed using the joint likelihood are substantially more accurate than those reconstructed using sequence alone. Using realistic gene tree topologies, branch lengths, and alignment sizes, we demonstrate that ALE produces more accurate gene trees even if the model of sequence evolution is greatly simplified. Finally, examining 1099 gene families from 36 cyanobacterial genomes we find that joint likelihood-based inference results in a striking reduction in apparent phylogenetic discord, with respectively. 24%, 59%, and 46% reductions in the mean numbers of duplications, transfers, and losses per gene family. The open source implementation of ALE is available from https://github.com/ssolo/ALE.git.


Assuntos
Classificação/métodos , Filogenia , Simulação por Computador , Cianobactérias/classificação , Cianobactérias/genética , Reprodutibilidade dos Testes , Análise de Sequência de DNA
11.
Leukemia ; 38(5): 981-990, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38429501

RESUMO

PICALM: MLLT10 fusion is a rare but recurrent genetic driver in acute leukemias. To better understand the genomic landscape of PICALM::MLLT10 (PM) positive acute leukemia, we performed genomic profiling and gene expression profiling in twenty PM-positive patients, including AML (n = 10), T-ALL/LLy (n = 8), Mixed-phenotype acute leukemia (MPAL), T/B (n = 1) and acute undifferentiated leukemia (AUL) (n = 1). Besides confirming the known activation of HOXA, differential gene expression analysis compared to hematopoietic stem cells demonstrated the enrichment of genes associated with cell proliferation-related pathways and relatively high expression of XPO1 in PM-AML and PM-T-ALL/LLy. Our study also suggested PHF6 disruption as a key cooperating event in PICALM::MLLT10-positive leukemias. In addition, we demonstrated differences in gene expression profiles as well as remarkably different spectra of co-occurring mutations between PM-AML and PM-T-ALL/LLy. Alterations affecting TP53 and NF1, hallmarks of PM-AML, are strongly associated with disease progression and relapse, whereas EZH2 alterations are highly enriched in PM-T-ALL/LLy. This comprehensive genomic and transcriptomic profiling provides insights into the pathogenesis and development of PICALM::MLLT10 positive acute leukemia.


Assuntos
Perfilação da Expressão Gênica , Proteínas de Fusão Oncogênica , Humanos , Proteínas de Fusão Oncogênica/genética , Criança , Adolescente , Masculino , Feminino , Adulto Jovem , Adulto , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Genômica/métodos , Fatores de Transcrição/genética , Pré-Escolar , Biomarcadores Tumorais/genética , Regulação Leucêmica da Expressão Gênica , Prognóstico , Transcriptoma
12.
Leukemia ; 38(5): 991-1002, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38454121

RESUMO

MGA (Max-gene associated) is a dual-specificity transcription factor that negatively regulates MYC-target genes to inhibit proliferation and promote differentiation. Loss-of-function mutations in MGA have been commonly identified in several hematological neoplasms, including acute myeloid leukemia (AML) with RUNX1::RUNX1T1, however, very little is known about the impact of these MGA alterations on normal hematopoiesis or disease progression. We show that representative MGA mutations identified in patient samples abolish protein-protein interactions and transcriptional activity. Using a series of human and mouse model systems, including a newly developed conditional knock-out mouse strain, we demonstrate that loss of MGA results in upregulation of MYC and E2F targets, cell cycle genes, mTOR signaling, and oxidative phosphorylation in normal hematopoietic cells, leading to enhanced proliferation. The loss of MGA induces an open chromatin state at promoters of genes involved in cell cycle and proliferation. RUNX1::RUNX1T1 expression in Mga-deficient murine hematopoietic cells leads to a more aggressive AML with a significantly shortened latency. These data show that MGA regulates multiple pro-proliferative pathways in hematopoietic cells and cooperates with the RUNX1::RUNX1T1 fusion oncoprotein to enhance leukemogenesis.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core , Proteínas de Ligação a DNA , Leucemia Mieloide Aguda , Mutação , Proteínas Proto-Oncogênicas , Proteína 1 Parceira de Translocação de RUNX1 , Animais , Humanos , Camundongos , Proliferação de Células , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Camundongos Knockout , Proteínas de Fusão Oncogênica/genética , Proteína 1 Parceira de Translocação de RUNX1/genética , Fatores de Transcrição/genética
13.
Genome Biol ; 25(1): 16, 2024 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-38216972

RESUMO

BACKGROUND: The oncogenic protein HOXA9 plays a critical role in leukemia transformation and maintenance, and its aberrant expression is a hallmark of most aggressive acute leukemia. Although inhibiting the upstream regulators of HOXA9 has been proven as a significant therapeutic intervention, the comprehensive regulation network controlling HOXA9 expression in leukemia has not been systematically investigated. RESULTS: Here, we perform genome-wide CRISPR/Cas9 screening in the HOXA9-driven reporter acute leukemia cells. We identify a poorly characterized RNA-binding protein, RBM5, as the top candidate gene required to maintain leukemia cell fitness. RBM5 is highly overexpressed in acute myeloid leukemia (AML) patients compared to healthy individuals. RBM5 loss triggered by CRISPR knockout and shRNA knockdown significantly impairs leukemia maintenance in vitro and in vivo. Through domain CRISPR screening, we reveal that RBM5 functions through a noncanonical transcriptional regulation circuitry rather than RNA splicing, such an effect depending on DNA-binding domains. By integrative analysis and functional assays, we identify HOXA9 as the downstream target of RBM5. Ectopic expression of HOXA9 rescues impaired leukemia cell proliferation upon RBM5 loss. Importantly, acute protein degradation of RBM5 through auxin-inducible degron system immediately reduces HOXA9 transcription. CONCLUSIONS: We identify RBM5 as a new upstream regulator of HOXA9 and reveal its essential role in controlling the survival of AML. These functional and molecular mechanisms further support RBM5 as a promising therapeutic target for myeloid leukemia treatment.


Assuntos
Proteínas de Homeodomínio , Leucemia Mieloide Aguda , Humanos , Proteínas de Ciclo Celular/metabolismo , Proliferação de Células , Proteínas de Ligação a DNA/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas Oncogênicas/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas Supressoras de Tumor/metabolismo
14.
Cell Rep Med ; 5(3): 101468, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38508144

RESUMO

Neuroblastoma with MYCN amplification (MNA) is a high-risk disease that has a poor survival rate. Neuroblastoma displays cellular heterogeneity, including more differentiated (adrenergic) and more primitive (mesenchymal) cellular states. Here, we demonstrate that MYCN oncoprotein promotes a cellular state switch in mesenchymal cells to an adrenergic state, accompanied by induction of histone lysine demethylase 4 family members (KDM4A-C) that act in concert to control the expression of MYCN and adrenergic core regulatory circulatory (CRC) transcription factors. Pharmacologic inhibition of KDM4 blocks expression of MYCN and the adrenergic CRC transcriptome with genome-wide induction of transcriptionally repressive H3K9me3, resulting in potent anticancer activity against neuroblastomas with MNA by inducing neuroblastic differentiation and apoptosis. Furthermore, a short-term KDM4 inhibition in combination with conventional, cytotoxic chemotherapy results in complete tumor responses of xenografts with MNA. Thus, KDM4 blockade may serve as a transformative strategy to target the adrenergic CRC dependencies in MNA neuroblastomas.


Assuntos
Histona Desmetilases , Neuroblastoma , Humanos , Proteína Proto-Oncogênica N-Myc/genética , Linhagem Celular Tumoral , Neuroblastoma/tratamento farmacológico , Neuroblastoma/genética , Proteínas Oncogênicas/metabolismo , Histona Desmetilases com o Domínio Jumonji/genética
15.
Nat Commun ; 14(1): 7464, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-38016946

RESUMO

Accumulating evidence indicates that HOXA9 dysregulation is necessary and sufficient for leukemic transformation and maintenance. However, it remains largely unknown how HOXA9, as a homeobox transcriptional factor, binds to noncoding regulatory sequences and controls the downstream genes. Here, we conduct dropout CRISPR screens against 229 HOXA9-bound peaks identified by ChIP-seq. Integrative data analysis identifies reproducible noncoding hits, including those located in the distal enhancer of FLT3 and intron of CDK6. The Cas9-editing and dCas9-KRAB silencing of the HOXA9-bound sites significantly reduce corresponding gene transcription and impair cell proliferation in vitro, and in vivo by transplantation into NSG female mice. In addition, RNA-seq, Q-PCR analysis, chromatin accessibility change, and chromatin conformation evaluation uncover the noncoding regulation mechanism of HOXA9 and its functional downstream genes. In summary, our work improves our understanding of how HOXA9-associated transcription programs reconstruct the regulatory network specifying MLL-r dependency.


Assuntos
Proteínas de Homeodomínio , Leucemia , Feminino , Camundongos , Animais , Proteínas de Homeodomínio/metabolismo , Fatores de Transcrição/metabolismo , Leucemia/genética , Proteínas de Neoplasias/metabolismo , Regulação para Cima , Cromatina , Regulação Leucêmica da Expressão Gênica
16.
Sci Adv ; 9(1): eabq3951, 2023 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-36608120

RESUMO

Metastases arise from rare cancer cells that successfully adapt to the diverse microenvironments encountered during dissemination through the bloodstream and colonization of distant tissues. How cancer cells acquire the ability to appropriately respond to microenvironmental stimuli remains largely unexplored. Here, we report an epigenetic pliancy mechanism that allows cancer cells to successfully metastasize. We find that a decline in the activity of the transcriptional repressor ZBTB18 defines metastasis-competent cancer cells in mouse models. Restoration of ZBTB18 activity reduces chromatin accessibility at the promoters of genes that drive metastasis, such as Tgfbr2, and this prevents TGFß1 pathway activation and consequently reduces cell migration and invasion. Besides repressing the expression of metastatic genes, ZBTB18 also induces widespread chromatin closing, a global epigenetic adaptation previously linked to reduced phenotypic flexibility. Thus, ZBTB18 is a potent chromatin regulator, and the loss of its activity enhances chromatin accessibility and transcriptional adaptations that promote the phenotypic changes required for metastasis.


Assuntos
Cromatina , Proteínas Repressoras , Animais , Camundongos , Cromatina/genética , Epigênese Genética , Proteínas Repressoras/genética
17.
Res Sq ; 2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37790524

RESUMO

MGA (Max-gene associated) is a dual-specificity transcription factor that negatively regulates MYC-target genes to inhibit proliferation and promote differentiation. Loss-of-function mutations in MGA have been commonly identified in several hematological neoplasms, including acute myeloid leukemia (AML) with RUNX1::RUNX1T1, however, very little is known about the impact of these MGA alterations on normal hematopoiesis or disease progression. We show that representative MGA mutations identified in patient samples abolish protein-protein interactions and transcriptional activity. Using a series of human and mouse model systems, including a newly developed conditional knock-out mouse strain, we demonstrate that loss of MGA results in upregulation of MYC and E2F targets, cell cycle genes, mTOR signaling, and oxidative phosphorylation in normal hematopoietic cells, leading to enhanced proliferation. The loss of MGA induces an open chromatin state at promotors of genes involved in cell cycle and proliferation. RUNX1::RUNX1T1 expression in Mga-deficient murine hematopoietic cells leads to a more aggressive AML with a significantly shortened latency. These data show that MGA regulates multiple pro-proliferative pathways in hematopoietic cells and cooperates with the RUNX1::RUNX1 T1 fusion oncoprotein to enhance leukemogenesis.

18.
medRxiv ; 2023 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-37873138

RESUMO

Sequence-based genetic testing currently identifies causative genetic variants in ∼50% of individuals with developmental and epileptic encephalopathies (DEEs). Aberrant changes in DNA methylation are implicated in various neurodevelopmental disorders but remain unstudied in DEEs. Rare epigenetic variations ("epivariants") can drive disease by modulating gene expression at single loci, whereas genome-wide DNA methylation changes can result in distinct "episignature" biomarkers for monogenic disorders in a growing number of rare diseases. Here, we interrogate the diagnostic utility of genome-wide DNA methylation array analysis on peripheral blood samples from 516 individuals with genetically unsolved DEEs who had previously undergone extensive genetic testing. We identified rare differentially methylated regions (DMRs) and explanatory episignatures to discover causative and candidate genetic etiologies in 10 individuals. We then used long-read sequencing to identify DNA variants underlying rare DMRs, including one balanced translocation, three CG-rich repeat expansions, and two copy number variants. We also identify pathogenic sequence variants associated with episignatures; some had been missed by previous exome sequencing. Although most DEE genes lack known episignatures, the increase in diagnostic yield for DNA methylation analysis in DEEs is comparable to the added yield of genome sequencing. Finally, we refine an episignature for CHD2 using an 850K methylation array which was further refined at higher CpG resolution using bisulfite sequencing to investigate potential insights into CHD2 pathophysiology. Our study demonstrates the diagnostic yield of genome-wide DNA methylation analysis to identify causal and candidate genetic causes as ∼2% (10/516) for unsolved DEE cases.

19.
Life Sci Alliance ; 5(1)2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34667079

RESUMO

DNA methylation at enhancers and CpG islands usually leads to gene repression, which is counteracted by DNA demethylation through the TET protein family. However, how TET enzymes are recruited and regulated at these genomic loci is not fully understood. Here, we identify TET2, the glycosyltransferase OGT and a previously undescribed proline and serine rich protein, PROSER1 as interactors of UTX, a component of the enhancer-associated MLL3/4 complexes. We find that PROSER1 mediates the interaction between OGT and TET2, thus promoting TET2 O-GlcNAcylation and protein stability. In addition, PROSER1, UTX, TET1/2, and OGT colocalize on many genomic elements genome-wide. Loss of PROSER1 results in lower enrichment of UTX, TET1/2, and OGT at enhancers and CpG islands, with a concomitant increase in DNA methylation and transcriptional down-regulation of associated target genes and increased DNA hypermethylation encroachment at H3K4me1-predisposed CpG islands. Furthermore, we provide evidence that PROSER1 acts as a more general regulator of OGT activity by controlling O-GlcNAcylation of multiple other chromatin signaling pathways. Taken together, this study describes for the first time a regulator of TET2 O-GlcNAcylation and its implications in mediating DNA demethylation at UTX-dependent enhancers and CpG islands and supports an important role for PROSER1 in regulating the function of various chromatin-associated proteins via OGT-mediated O-GlcNAcylation.


Assuntos
Ilhas de CpG , Desmetilação do DNA , Proteínas de Ligação a DNA/metabolismo , Dioxigenases/metabolismo , Elementos Facilitadores Genéticos , Histona Desmetilases/metabolismo , Animais , Linhagem Celular , Cromatina/genética , Cromatina/metabolismo , Sequenciamento de Cromatina por Imunoprecipitação , Biologia Computacional/métodos , Técnicas de Silenciamento de Genes , Glicosilação , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Camundongos , Modelos Biológicos , Ligação Proteica , Transporte Proteico
20.
Life Sci Alliance ; 5(11)2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35820704

RESUMO

The mitotic deacetylase complex MiDAC has recently been shown to play a vital physiological role in embryonic development and neurite outgrowth. However, how MiDAC functionally intersects with other chromatin-modifying regulators is poorly understood. Here, we describe a physical interaction between the histone H3K27 demethylase UTX, a complex-specific subunit of the enhancer-associated MLL3/4 complexes, and MiDAC. We demonstrate that UTX bridges the association of the MLL3/4 complexes and MiDAC by interacting with ELMSAN1, a scaffolding subunit of MiDAC. Our data suggest that MiDAC constitutes a negative genome-wide regulator of H4K20ac, an activity which is counteracted by the MLL3/4 complexes. MiDAC and the MLL3/4 complexes co-localize at many genomic regions, which are enriched for H4K20ac and the enhancer marks H3K4me1, H3K4me2, and H3K27ac. We find that MiDAC antagonizes the recruitment of UTX and MLL4 and negatively regulates H4K20ac, and to a lesser extent H3K4me2 and H3K27ac, resulting in transcriptional attenuation of associated genes. In summary, our findings provide a paradigm how the opposing roles of chromatin-modifying components, such as MiDAC and the MLL3/4 complexes, balance the transcriptional output of specific gene expression programs.


Assuntos
Elementos Facilitadores Genéticos , Histonas , Cromatina/genética , Elementos Facilitadores Genéticos/genética , Expressão Gênica , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/genética , Histonas/metabolismo
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