RESUMO
The blood system serves as a key model for cell differentiation and cancer. It is orchestrated by precise spatiotemporal expression of crucial transcription factors. One of the key master regulators in the hematopoietic systems is PU.1. Reduced levels of PU.1 are characteristic for human acute myeloid leukemia (AML) and are known to induce AML in mouse models. Here, we show that transcriptional downregulation of PU.1 is an active process involving an alternative promoter in intron 3 that is induced by RUNX transcription factors driving noncoding antisense transcription. Core-binding factor (CBF) fusions RUNX1-ETO and CBFß-MYH11 in t(8;21) and inv(16) AML, respectively, activate the PU.1 antisense promoter that results in a shift from sense toward antisense transcription and myeloid differentiation blockade. In patients with CBF-AML, we found that an elevated antisense/sense transcript and promoter accessibility ratio represents a hallmark compared with normal karyotype AML or healthy CD34+ cells. Competitive interaction of an enhancer with the proximal or the antisense promoter forms a binary on/off switch for either myeloid or T-cell development. Leukemic CBF fusions thus use a physiological mechanism used by T cells to decrease sense transcription. Our study is the first example of a sense/antisense promoter competition as a crucial functional switch for gene expression perturbation by oncogenes. Hence, this disease mechanism reveals a previously unknown Achilles heel for future precise therapeutic targeting of oncogene-induced chromatin remodeling.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade beta de Fator de Ligação ao Core/genética , Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide Aguda/genética , Proteínas Proto-Oncogênicas/genética , Transativadores/genética , Elementos Antissenso (Genética)/genética , Linhagem Celular Tumoral , Fusão Gênica , Humanos , Proteínas de Fusão Oncogênica/genética , Regiões Promotoras Genéticas , Proteína 1 Parceira de Translocação de RUNX1/genética , Células Tumorais CultivadasRESUMO
Human induced pluripotent stem (iPS) cells can be derived from lineage-restricted cells and represent an important tool to develop novel patient-specific cell therapies and research models for inherited and acquired diseases. Recently, patient-derived iPS cells, containing donor genetic background, have offered a breakthrough approach to study human genetics of neurodegenerative diseases. By offering an unlimited source of patient-specific disease-relevant cells, iPS cells hold great promise for understanding disease mechanisms, identifying molecular targets and developing phenotypic screens for drug discovery. This review will discuss the potential impact of using iPS cell-derived models in multiple sclerosis (MS) research and highlight some of the current challenges and prospective for generating novel therapeutic treatments for MS patients.
Assuntos
Diferenciação Celular/genética , Terapia Baseada em Transplante de Células e Tecidos , Células-Tronco Pluripotentes Induzidas , Esclerose Múltipla/terapia , Linhagem da Célula , Humanos , Esclerose Múltipla/genética , Medicina de PrecisãoRESUMO
Reprogramming somatic cells into induced pluripotent stem (iPS) cells is nowadays approaching effectiveness and clinical grade. Potential uses of this technology include predictive toxicology, drug screening, pathogenetic studies and transplantation. Here, we review the basis of current iPS cell technology and potential applications in hematology, ranging from disease modeling of congenital and acquired hemopathies to hematopoietic stem and other blood cell transplantation.
Assuntos
Células-Tronco Pluripotentes Induzidas/fisiologia , Animais , Hematologia/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Células-Tronco Pluripotentes Induzidas/citologiaRESUMO
BACKGROUND: Polymorphisms in genes involved in detoxification and DNA-repair pathways may modify the individual's risk for genomic damage, and, as a consequence, the risk of developing malignant diseases. PATIENTS AND METHODS: We performed a case-control study including 160 cases of acute myeloid leukaemia (AML) and 162 matched controls to test the impact of six genomic polymorphisms on the risk to develop AML and/or therapy-related AML. RESULTS: We found a significantly higher prevalence of the polymorphic variants RAD51-G135C and CYP3A4-A-290G genes in AML cases, when compared with controls (P = 0.02 and P = 0.04), increasing the risk of AML 2.1-folds (95% CI: 1.1-4.0) and 3.2-fold (95% CI: 1.1-11.5), respectively. Carriers of both the RAD51-G135C and CYP3A4-A-290G variants were at highest AML risk (P = 0.003; OR:13,6; 95% CI: 2.0-585.5), suggesting a synergistic effect between these polymorphisms. CONCLUSIONS: These results suggest that polymorphic variants in DNA-repair and detoxification enzymes may co-operate in modulating the individual's risk of AML.