RESUMO
In this study, we delve into the impact of genotoxic anticancer drug treatment on the chromatin structure of human cells, with a particular focus on the effects of doxorubicin. Using Hi-C, ChIP-seq, and RNA-seq, we explore the changes in chromatin architecture brought about by doxorubicin and ICRF193. Our results indicate that physiologically relevant doses of doxorubicin lead to a local reduction in Hi-C interactions in certain genomic regions that contain active promoters, with changes in chromatin architecture occurring independently of Top2 inhibition, cell cycle arrest, and differential gene expression. Inside the regions with decreased interactions, we detected redistribution of RAD21 around the peaks of H3K27 acetylation. Our study also revealed a common structural pattern in the regions with altered architecture, characterized by two large domains separated from each other. Additionally, doxorubicin was found to increase CTCF binding in H3K27 acetylated regions. Furthermore, we discovered that Top2-dependent chemotherapy causes changes in the distance decay of Hi-C contacts, which are driven by direct and indirect inhibitors. Our proposed model suggests that doxorubicin-induced DSBs cause cohesin redistribution, which leads to increased insulation on actively transcribed TAD boundaries. Our findings underscore the significant impact of genotoxic anticancer treatment on the chromatin structure of the human genome.
Assuntos
Cromatina , Cromossomos , Humanos , Fator de Ligação a CCCTC/genética , Sítios de Ligação , Cromossomos/metabolismo , Doxorrubicina/farmacologiaRESUMO
The differentiation of self-renewing progenitor cells requires not only the regulation of lineage- and developmental stage-specific genes but also the coordinated adaptation of housekeeping functions from a metabolically active, proliferative state toward quiescence. How metabolic and cell-cycle states are coordinated with the regulation of cell type-specific genes is an important question, because dissociation between differentiation, cell cycle, and metabolic states is a hallmark of cancer. Here, we use a model system to systematically identify key transcriptional regulators of Ikaros-dependent B cell-progenitor differentiation. We find that the coordinated regulation of housekeeping functions and tissue-specific gene expression requires a feedforward circuit whereby Ikaros down-regulates the expression of Myc. Our findings show how coordination between differentiation and housekeeping states can be achieved by interconnected regulators. Similar principles likely coordinate differentiation and housekeeping functions during progenitor cell differentiation in other cell lineages.
Assuntos
Linfócitos B/citologia , Genes myc , Células Precursoras de Linfócitos B/citologia , Animais , Linfócitos B/metabolismo , Ciclo Celular/fisiologia , Diferenciação Celular/genética , Linhagem da Célula , Bases de Dados Genéticas , Regulação para Baixo , Regulação da Expressão Gênica , Genes Essenciais , Humanos , Fator de Transcrição Ikaros/metabolismo , Ativação Linfocitária , Camundongos , Células Precursoras de Linfócitos B/metabolismo , Fatores de Transcrição/metabolismoRESUMO
Cohesin is important for 3D genome organization. Nevertheless, even the complete removal of cohesin has surprisingly little impact on steady-state gene transcription and enhancer activity. Here we show that cohesin is required for the core transcriptional response of primary macrophages to microbial signals, and for inducible enhancer activity that underpins inflammatory gene expression. Consistent with a role for inflammatory signals in promoting myeloid differentiation of hematopoietic stem and progenitor cells (HPSCs), cohesin mutations in HSPCs led to reduced inflammatory gene expression and increased resistance to differentiation-inducing inflammatory stimuli. These findings uncover an unexpected dependence of inducible gene expression on cohesin, link cohesin with myeloid differentiation, and may help explain the prevalence of cohesin mutations in human acute myeloid leukemia.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Diferenciação Celular/genética , Autorrenovação Celular/genética , Proteínas Cromossômicas não Histona/metabolismo , Células-Tronco Hematopoéticas/fisiologia , Leucemia Mieloide Aguda/genética , Macrófagos/fisiologia , Proteínas Nucleares/genética , Fosfoproteínas/genética , Animais , Proteínas de Ciclo Celular/genética , Células Cultivadas , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA , Regulação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Inflamação/genética , Lipopolissacarídeos/imunologia , Camundongos , Camundongos Knockout , Mutação/genética , CoesinasRESUMO
A recent article makes a compelling case for a new mechanism by which heterozygous mutations in isocitrate dehydrogenases (IDH1/2)--implicated in cancer--undermine gene regulation. 2-Hydroxyglutarate (2HG) produced by mutant IDH alters the binding of the chromosomal organizer protein CTCF, disrupting the spatial and regulatory organization of the genome.