RESUMEN
Cancer cells reprogram their energy metabolic system from the mitochondrial oxidative phosphorylation (OXPHOS) pathway to a glucose-dependent aerobic glycolysis pathway. This metabolic reprogramming phenomenon is known as the Warburg effect, a significant hallmark of cancer. However, the detailed mechanisms underlying this event or triggering this reprogramming remain largely unclear. Here, we found that histone H2B monoubiquitination (H2Bub1) negatively regulates the Warburg effect and tumorigenesis in human lung cancer cells (H1299 and A549 cell lines) likely through controlling the expression of multiple mitochondrial respiratory genes, which are essential for OXPHOS. Moreover, our work also suggested that pyruvate kinase M2 (PKM2), the rate-limiting enzyme of glycolysis, can directly interact with H2B in vivo and in vitro and negatively regulate the level of H2Bub1. The inhibition of cell proliferation and nude mice xenograft of human lung cancer cells induced by PKM2 knockdown can be partially rescued through lowering H2Bub1 levels, which indicates that the oncogenic function of PKM2 is achieved, at least partially, through the control of H2Bub1. Furthermore, PKM2 and H2Bub1 levels are negatively correlated in cancer specimens. Therefore, these findings not only provide a novel mechanism triggering the Warburg effect that is mediated through an epigenetic pathway (H2Bub1) but also reveal a novel metabolic regulator (PKM2) for the epigenetic mark H2Bub1. Thus, the PKM2-H2Bub1 axis may become a promising cancer therapeutic target.
Asunto(s)
Epigénesis Genética , Histonas/metabolismo , Ubiquitinación , Efecto Warburg en Oncología , Animales , Carcinogénesis/genética , Carcinogénesis/patología , Proteínas Portadoras/metabolismo , Línea Celular Tumoral , Proliferación Celular/genética , Respiración de la Célula/genética , Células HEK293 , Humanos , Masculino , Proteínas de la Membrana/metabolismo , Ratones Endogámicos BALB C , Ratones Desnudos , Mitocondrias/genética , Simulación del Acoplamiento Molecular , Unión Proteica , Hormonas Tiroideas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Proteínas de Unión a Hormona TiroideRESUMEN
Multiple sclerosis (MS) is an inflammatory demyelinating disease of CNS. Astragalus polysaccharides (APS), the main active extract from astragalus membranaceus which is a kind of traditional Chinese medicinal herb, is associated with a variety of immunomodulatory activities. We have evaluated the therapeutic effects of APS in the animal model of MS, experimental autoimmune encephalomyelitis (EAE). It was found that APS could effectively alleviate EAE through inhibiting MOG35-55-specific T cell proliferation and reducing the expression of proinflammatory cytokines, which is mediated by up-regulating the expression of PD-1/PD-Ls signaling pathway. Our results demonstrated that EAE could be suppressed significantly by APS administration. It indicated that APS might be a potential of developing innovative drug for the therapy of MS.
Asunto(s)
Antiinflamatorios/uso terapéutico , Astragalus propinquus/química , Antígeno B7-H1/biosíntesis , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Fitoterapia , Gomas de Plantas/uso terapéutico , Proteína 2 Ligando de Muerte Celular Programada 1/biosíntesis , Receptor de Muerte Celular Programada 1/biosíntesis , Transducción de Señal/efectos de los fármacos , Animales , Antiinflamatorios/farmacología , Antígeno B7-H1/genética , Antígeno B7-H1/fisiología , Citocinas/biosíntesis , Citocinas/genética , Encefalomielitis Autoinmune Experimental/inducido químicamente , Femenino , Inflamación , Ratones , Ratones Endogámicos C57BL , Glicoproteína Mielina-Oligodendrócito/toxicidad , Fragmentos de Péptidos/toxicidad , Gomas de Plantas/farmacología , Proteína 2 Ligando de Muerte Celular Programada 1/genética , Proteína 2 Ligando de Muerte Celular Programada 1/fisiología , Receptor de Muerte Celular Programada 1/genética , Receptor de Muerte Celular Programada 1/fisiología , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Médula Espinal/efectos de los fármacos , Médula Espinal/inmunología , Médula Espinal/patología , Subgrupos de Linfocitos T/efectos de los fármacos , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/patología , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Dysregulation of the homeostatic balance of histone H3 di- and tri-methyl lysine 27 (H3K27me2/3) levels caused by the mis-sense mutation of histone H3 (H3K27M) is reported to be associated with various types of cancers. In this study, we found that reduction in H3K27me2/3 caused by H3.1K27M, a mutation of H3 variants found in patients with diffuse intrinsic pontine glioma (DIPG), dramatically attenuated the presence of 53BP1 (also known as TP53BP1) foci and the capability of non-homologous end joining (NHEJ) in human dermal fibroblasts. H3.1K27M mutant cells showed increased rates of genomic insertions/deletions and copy number variations, as well as an increase in p53-dependent apoptosis. We further showed that both hypo-H3K27me2/3 and H3.1K27M interacted with FANCD2, a central player in the choice of DNA repair pathway. H3.1K27M triggered the accumulation of FANCD2 on chromatin, suggesting an interaction between H3.1K27M and FANCD2. Interestingly, knockdown of FANCD2 in H3.1K27M cells recovered the number of 53BP1-positive foci, NHEJ efficiency and apoptosis rate. Although these findings in HDF cells may differ from the endogenous regulation of the H3.1K27M mutant in the specific tumor context of DIPG, our results suggest a new model by which H3K27me2/3 facilitates NHEJ and the maintenance of genome stability.This article has an associated First Person interview with the first author of the paper.
Asunto(s)
Cromatina/metabolismo , Reparación del ADN por Unión de Extremidades , Enzimas Reparadoras del ADN/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/metabolismo , Histonas/metabolismo , Neoplasias del Tronco Encefálico/genética , Neoplasias del Tronco Encefálico/metabolismo , Línea Celular , Cromatina/genética , Reparación del ADN , Enzimas Reparadoras del ADN/genética , Proteínas de Unión al ADN/genética , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/genética , Fibroblastos , Inestabilidad Genómica , Glioma/genética , Glioma/metabolismo , Células HEK293 , Histonas/genética , Humanos , Metilación , Proteína 1 de Unión al Supresor Tumoral P53/genética , Proteína 1 de Unión al Supresor Tumoral P53/metabolismoRESUMEN
Autophagy is an evolutionarily conserved cellular process that primarily participates in lysosome-mediated protein degradation. Although autophagy is a cytoplasmic event, how epigenetic pathways are involved in the regulation of autophagy remains incompletely understood. Here, we found that H2B monoubiquitination (H2Bub1) is down-regulated in cells under starvation conditions and that the decrease in H2Bub1 results in the activation of autophagy. We also identified that the deubiquitinase USP44 is responsible for the starvation-induced decrease in H2Bub1. Furthermore, the changes in H2Bub1 affect the transcription of genes involved in the regulation of autophagy. Therefore, this study reveals a novel epigenetic pathway for the regulation of autophagy through H2Bub1.
Asunto(s)
Autofagia/genética , Epigénesis Genética , Histonas/metabolismo , Ubiquitinación/genética , Animales , Proteínas Relacionadas con la Autofagia/antagonistas & inhibidores , Proteínas Relacionadas con la Autofagia/genética , Proteínas Relacionadas con la Autofagia/metabolismo , Diferenciación Celular , ADN (Citosina-5-)-Metiltransferasas/metabolismo , ADN Metiltransferasa 3A , Regulación hacia Abajo , Células Madre Embrionarias/citología , Células Madre Embrionarias/metabolismo , Endopeptidasas/genética , Endopeptidasas/metabolismo , Técnicas de Silenciamiento del Gen , Células HEK293 , Células HeLa , Histonas/química , Histonas/genética , Humanos , Ratones , Modelos Biológicos , ARN Interferente Pequeño/genética , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Ubiquitina Tiolesterasa , Proteasas Ubiquitina-Específicas/antagonistas & inhibidores , Proteasas Ubiquitina-Específicas/genética , Proteasas Ubiquitina-Específicas/metabolismo , ADN Metiltransferasa 3BRESUMEN
Stem-cell-derived hepatocyte transplantation is considered as a potential method for the therapy of acute and chronic liver failure. However, the low efficiency of differentiation into mature and functional hepatocytes remains a major challenge for clinical applications. By using polyethyleneimine-modified silica nanoparticles, this study develops a system for sustained delivery of growth factors, leading to induce hepatocyte-like cells (iHeps) from mouse embryonic stem cells (mESCs) and improve the expression of endoderm and hepatocyte-specific genes and proteins significantly, thus producing a higher population of functional hepatocytes in vitro. When transplanted into liver-injured mice after four weeks, mESC-derived definitive endoderm cells treated with this delivery system show higher integration efficiency into the host liver, differentiated into iHeps in vivo and significantly restored the injured liver. Therefore, these findings reveal the multiple advantages of functionalized nanoparticles to serve as efficient delivery platforms to promote stem cell differentiation in the regenerative medicine.
RESUMEN
Chromatin is a highly organized and dynamic structure in eukaryotic cells. The change of chromatin structure is essential in many cellular processes, such as gene transcription, DNA damage repair and others. Anti-silencing function 1 (ASF1) is a histone chaperone that participates in chromatin higher-order organization and is required for appropriate chromatin assembly. In this study, we identified the E2 ubiquitin-conjugating enzyme RAD6 as an evolutionary conserved interacting protein of ASF1 in D. melanogaster and H. sapiens that promotes the turnover of ASF1A by cooperating with a well-known E3 ligase, MDM2, via ubiquitin-proteasome pathway in H. sapiens. Further functional analyses indicated that the interplay between RAD6 and ASF1A associates with tumorigenesis. Together, these data suggest that the RAD6-MDM2 ubiquitin ligase machinery is critical for the degradation of chromatin-related proteins.
Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Enzimas Ubiquitina-Conjugadoras/metabolismo , Animales , Western Blotting , Proteínas de Ciclo Celular/genética , Línea Celular , Línea Celular Tumoral , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citología , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Regulación Neoplásica de la Expresión Génica , Células HEK293 , Células Hep G2 , Histonas/metabolismo , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Microscopía Confocal , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Proteínas Proto-Oncogénicas c-mdm2/genética , Interferencia de ARN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Enzimas Ubiquitina-Conjugadoras/genética , UbiquitinaciónRESUMEN
Histone H2B monoubiquitination is a key histone modification that has significant effects on chromatin higher-order structure and gene transcription. Multiple biological processes have been suggested to be tightly related to the dynamics of H2B monoubiquitination. However, a comprehensive understanding of biological roles of H2B monoubiquitination is still poorly understood. In the present study, we developed an efficient tool to disrupt endogenous H2B monoubiquitination levels by using an H2BK120R mutant construct expressed in human cells. Genome-wide microarray analysis of these cells revealed a potential global view of biological functions of H2B monoubiquitination. Bioinformatics analysis of our data demonstrated that while H2B monoubiquitination expectedly affected a number of previously reported biological pathways, we also uncovered the influence of this histone modification on many novel biological processes. Therefore, our work provided valuable information for understanding the role of H2B monoubiquitination and indicated potential directions for its further studies.
Asunto(s)
Histonas/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Ubiquitinación , Animales , Diferenciación Celular/genética , Cromatina/metabolismo , Daño del ADN/genética , Reparación del ADN/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Células HEK293 , Células HeLa , Histonas/genética , Humanos , Ratones , Células Madre Embrionarias de Ratones/citología , Proteínas Mutantes/metabolismo , Mutación/genética , Ubiquitina/metabolismoRESUMEN
Protein ubiquitinylation regulates protein stability and activity. RAD6, an E2 ubiquitin-conjugating enzyme, which that has been substantially biochemically characterized, functions in a number of biologically relevant pathways, including cell cycle progression. In this study, we show that RAD6 promotes the G1-S transition and cell proliferation by regulating the expression of cyclin D1 (CCND1) in human cells. Furthermore, our data indicate that RAD6 influences the transcription of CCND1 by increasing monoubiquitinylation of histone H2B and trimethylation of H3K4 in the CCND1 promoter region. Our study presents, for the first time, an evidence for the function of RAD6 in cell cycle progression and cell proliferation in human cells, raising the possibility that RAD6 could be a new target for molecular diagnosis and prognosis in cancer therapeutics.
