RESUMEN
Many oncogenic insults deregulate RNA splicing, often leading to hypersensitivity of tumors to spliceosome-targeted therapies (STTs). However, the mechanisms by which STTs selectively kill cancers remain largely unknown. Herein, we discover that mis-spliced RNA itself is a molecular trigger for tumor killing through viral mimicry. In MYC-driven triple-negative breast cancer, STTs cause widespread cytoplasmic accumulation of mis-spliced mRNAs, many of which form double-stranded structures. Double-stranded RNA (dsRNA)-binding proteins recognize these endogenous dsRNAs, triggering antiviral signaling and extrinsic apoptosis. In immune-competent models of breast cancer, STTs cause tumor cell-intrinsic antiviral signaling, downstream adaptive immune signaling, and tumor cell death. Furthermore, RNA mis-splicing in human breast cancers correlates with innate and adaptive immune signatures, especially in MYC-amplified tumors that are typically immune cold. These findings indicate that dsRNA-sensing pathways respond to global aberrations of RNA splicing in cancer and provoke the hypothesis that STTs may provide unexplored strategies to activate anti-tumor immune pathways.
Asunto(s)
Antivirales/farmacología , Inmunidad/efectos de los fármacos , Empalmosomas/metabolismo , Neoplasias de la Mama Triple Negativas/inmunología , Neoplasias de la Mama Triple Negativas/patología , Inmunidad Adaptativa/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Citoplasma/efectos de los fármacos , Citoplasma/metabolismo , Femenino , Amplificación de Genes/efectos de los fármacos , Humanos , Intrones/genética , Ratones , Terapia Molecular Dirigida , Proteínas Proto-Oncogénicas c-myc/metabolismo , Empalme del ARN/efectos de los fármacos , Empalme del ARN/genética , ARN Bicatenario/metabolismo , Transducción de Señal/efectos de los fármacos , Empalmosomas/efectos de los fármacos , Neoplasias de la Mama Triple Negativas/genéticaRESUMEN
The NRF2 transcription factor controls a cell stress program that is implicated in cancer and there is great interest in targeting NRF2 for therapy. We show that NRF2 activity depends on Fructosamine-3-kinase (FN3K)-a kinase that triggers protein de-glycation. In its absence, NRF2 is extensively glycated, unstable, and defective at binding to small MAF proteins and transcriptional activation. Moreover, the development of hepatocellular carcinoma triggered by MYC and Keap1 inactivation depends on FN3K in vivo. N-acetyl cysteine treatment partially rescues the effects of FN3K loss on NRF2 driven tumor phenotypes indicating a key role for NRF2-mediated redox balance. Mass spectrometry reveals that other proteins undergo FN3K-sensitive glycation, including translation factors, heat shock proteins, and histones. How glycation affects their functions remains to be defined. In summary, our study reveals a surprising role for the glycation of cellular proteins and implicates FN3K as targetable modulator of NRF2 activity in cancer.
Asunto(s)
Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Animales , Carcinoma Hepatocelular/patología , Femenino , Técnicas de Silenciamiento del Gen , Glucosa/metabolismo , Glicosilación , Células HEK293 , Células Hep G2 , Xenoinjertos , Humanos , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Neoplasias Hepáticas/patología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones Desnudos , Ratones SCID , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Transducción GenéticaRESUMEN
Nuclear pore complexes (NPCs) regulate nuclear-cytoplasmic transport, transcription, and genome integrity in eukaryotic cells. However, their functional roles in cancer remain poorly understood. We interrogated the evolutionary transcriptomic landscape of NPC components, nucleoporins (Nups), from primary to advanced metastatic human prostate cancer (PC). Focused loss-of-function genetic screen of top-upregulated Nups in aggressive PC models identified POM121 as a key contributor to PC aggressiveness. Mechanistically, POM121 promoted PC progression by enhancing importin-dependent nuclear transport of key oncogenic (E2F1, MYC) and PC-specific (AR-GATA2) transcription factors, uncovering a pharmacologically targetable axis that, when inhibited, decreased tumor growth, restored standard therapy efficacy, and improved survival in patient-derived pre-clinical models. Our studies molecularly establish a role of NPCs in PC progression and give a rationale for NPC-regulated nuclear import targeting as a therapeutic strategy for lethal PC. These findings may have implications for understanding how NPC deregulation contributes to the pathogenesis of other tumor types.
Asunto(s)
Factor de Transcripción E2F1/metabolismo , Glicoproteínas de Membrana/metabolismo , Poro Nuclear/fisiología , Neoplasias de la Próstata/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Factores de Transcripción/metabolismo , Transporte Activo de Núcleo Celular , Carcinogénesis , Núcleo Celular/metabolismo , Proliferación Celular , Factor de Transcripción GATA2/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Membrana Nuclear , Proteínas de Complejo Poro Nuclear , Transducción de SeñalRESUMEN
While mutations affecting protein-coding regions have been examined across many cancers, structural variants at the genome-wide level are still poorly defined. Through integrative deep whole-genome and -transcriptome analysis of 101 castration-resistant prostate cancer metastases (109X tumor/38X normal coverage), we identified structural variants altering critical regulators of tumorigenesis and progression not detectable by exome approaches. Notably, we observed amplification of an intergenic enhancer region 624 kb upstream of the androgen receptor (AR) in 81% of patients, correlating with increased AR expression. Tandem duplication hotspots also occur near MYC, in lncRNAs associated with post-translational MYC regulation. Classes of structural variations were linked to distinct DNA repair deficiencies, suggesting their etiology, including associations of CDK12 mutation with tandem duplications, TP53 inactivation with inverted rearrangements and chromothripsis, and BRCA2 inactivation with deletions. Together, these observations provide a comprehensive view of how structural variations affect critical regulators in metastatic prostate cancer.
Asunto(s)
Variación Estructural del Genoma/genética , Neoplasias de la Próstata/genética , Anciano , Anciano de 80 o más Años , Proteína BRCA2/metabolismo , Quinasas Ciclina-Dependientes/metabolismo , Variaciones en el Número de Copia de ADN , Exoma , Perfilación de la Expresión Génica/métodos , Genómica/métodos , Humanos , Masculino , Persona de Mediana Edad , Mutación , Metástasis de la Neoplasia/genética , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Receptores Androgénicos/genética , Receptores Androgénicos/metabolismo , Secuencias Repetidas en Tándem/genética , Proteína p53 Supresora de Tumor/metabolismo , Secuenciación Completa del Genoma/métodosRESUMEN
The super elongation complex (SEC) is required for robust and productive transcription through release of RNA polymerase II (Pol II) with its P-TEFb module and promoting transcriptional processivity with its ELL2 subunit. Malfunction of SEC contributes to multiple human diseases including cancer. Here, we identify peptidomimetic lead compounds, KL-1 and its structural homolog KL-2, which disrupt the interaction between the SEC scaffolding protein AFF4 and P-TEFb, resulting in impaired release of Pol II from promoter-proximal pause sites and a reduced average rate of processive transcription elongation. SEC is required for induction of heat-shock genes and treating cells with KL-1 and KL-2 attenuates the heat-shock response from Drosophila to human. SEC inhibition downregulates MYC and MYC-dependent transcriptional programs in mammalian cells and delays tumor progression in a mouse xenograft model of MYC-driven cancer, indicating that small-molecule disruptors of SEC could be used for targeted therapy of MYC-induced cancer.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias Experimentales/tratamiento farmacológico , Factor B de Elongación Transcripcional Positiva/metabolismo , Proteínas Represoras/metabolismo , Elongación de la Transcripción Genética/efectos de los fármacos , Factores de Elongación Transcripcional/metabolismo , Animales , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Drosophila , Femenino , Células HCT116 , Células HEK293 , Respuesta al Choque Térmico , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Unión Proteica/efectos de los fármacos , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , ARN Polimerasa II/metabolismo , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacologíaRESUMEN
R-2-hydroxyglutarate (R-2HG), produced at high levels by mutant isocitrate dehydrogenase 1/2 (IDH1/2) enzymes, was reported as an oncometabolite. We show here that R-2HG also exerts a broad anti-leukemic activity in vitro and in vivo by inhibiting leukemia cell proliferation/viability and by promoting cell-cycle arrest and apoptosis. Mechanistically, R-2HG inhibits fat mass and obesity-associated protein (FTO) activity, thereby increasing global N6-methyladenosine (m6A) RNA modification in R-2HG-sensitive leukemia cells, which in turn decreases the stability of MYC/CEBPA transcripts, leading to the suppression of relevant pathways. Ectopically expressed mutant IDH1 and S-2HG recapitulate the effects of R-2HG. High levels of FTO sensitize leukemic cells to R-2HG, whereas hyperactivation of MYC signaling confers resistance that can be reversed by the inhibition of MYC signaling. R-2HG also displays anti-tumor activity in glioma. Collectively, while R-2HG accumulated in IDH1/2 mutant cancers contributes to cancer initiation, our work demonstrates anti-tumor effects of 2HG in inhibiting proliferation/survival of FTO-high cancer cells via targeting FTO/m6A/MYC/CEBPA signaling.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias Encefálicas/tratamiento farmacológico , Glioma/tratamiento farmacológico , Glutaratos/farmacología , Leucemia/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Adenosina/análogos & derivados , Adenosina/metabolismo , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/metabolismo , Animales , Antineoplásicos/uso terapéutico , Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Línea Celular Tumoral , Glutaratos/uso terapéutico , Células HEK293 , Humanos , Células Jurkat , Ratones , Proteínas Proto-Oncogénicas c-myc/metabolismo , Procesamiento Postranscripcional del ARNRESUMEN
Cyclin-dependent kinase 9 (CDK9) promotes transcriptional elongation through RNAPII pause release. We now report that CDK9 is also essential for maintaining gene silencing at heterochromatic loci. Through a live cell drug screen with genetic confirmation, we discovered that CDK9 inhibition reactivates epigenetically silenced genes in cancer, leading to restored tumor suppressor gene expression, cell differentiation, and activation of endogenous retrovirus genes. CDK9 inhibition dephosphorylates the SWI/SNF protein BRG1, which contributes to gene reactivation. By optimization through gene expression, we developed a highly selective CDK9 inhibitor (MC180295, IC50 = 5 nM) that has broad anti-cancer activity in vitro and is effective in in vivo cancer models. Additionally, CDK9 inhibition sensitizes to the immune checkpoint inhibitor α-PD-1 in vivo, making it an excellent target for epigenetic therapy of cancer.
Asunto(s)
Quinasa 9 Dependiente de la Ciclina/metabolismo , Animales , Línea Celular Tumoral , Quinasa 9 Dependiente de la Ciclina/antagonistas & inhibidores , Quinasa 9 Dependiente de la Ciclina/genética , ADN Helicasas/genética , ADN Helicasas/metabolismo , Metilación de ADN , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-myc/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacología , Relación Estructura-Actividad , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
The fusion oncoprotein CBFß-SMMHC, expressed in leukemia cases with chromosome 16 inversion, drives leukemia development and maintenance by altering the activity of the transcription factor RUNX1. Here, we demonstrate that CBFß-SMMHC maintains cell viability by neutralizing RUNX1-mediated repression of MYC expression. Upon pharmacologic inhibition of the CBFß-SMMHC/RUNX1 interaction, RUNX1 shows increased binding at three MYC distal enhancers, where it represses MYC expression by mediating the replacement of the SWI/SNF complex component BRG1 with the polycomb-repressive complex component RING1B, leading to apoptosis. Combining the CBFß-SMMHC inhibitor with the BET inhibitor JQ1 eliminates inv(16) leukemia in human cells and a mouse model. Enhancer-interaction analysis indicated that the three enhancers are physically connected with the MYC promoter, and genome-editing analysis demonstrated that they are functionally implicated in deregulation of MYC expression. This study reveals a mechanism whereby CBFß-SMMHC drives leukemia maintenance and suggests that inhibitors targeting chromatin activity may prove effective in inv(16) leukemia therapy.
Asunto(s)
Apoptosis , Cromatina/metabolismo , Proteínas de Fusión Oncogénica/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-myc/metabolismo , Animales , Apoptosis/efectos de los fármacos , Azepinas/farmacología , Azepinas/uso terapéutico , Bencimidazoles/farmacología , Bencimidazoles/uso terapéutico , Línea Celular Tumoral , Proteínas Cromosómicas no Histona/química , Proteínas Cromosómicas no Histona/metabolismo , Inversión Cromosómica/efectos de los fármacos , Subunidad alfa 2 del Factor de Unión al Sitio Principal/química , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , ADN/química , ADN/metabolismo , ADN Helicasas/metabolismo , Modelos Animales de Enfermedad , Humanos , Estimación de Kaplan-Meier , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/mortalidad , Leucemia Mieloide Aguda/patología , Ratones , Ratones Endogámicos C57BL , Proteínas Nucleares/metabolismo , Proteínas de Fusión Oncogénica/metabolismo , Complejo Represivo Polycomb 1/metabolismo , Regiones Promotoras Genéticas , Unión Proteica , Proteínas Proto-Oncogénicas c-myc/genética , Factores de Transcripción/química , Factores de Transcripción/metabolismo , Triazoles/farmacología , Triazoles/uso terapéuticoRESUMEN
Oct4, Sox2, Klf4, and cMyc (OSKM) reprogram somatic cells to pluripotency. To gain a mechanistic understanding of their function, we mapped OSKM-binding, stage-specific transcription factors (TFs), and chromatin states in discrete reprogramming stages and performed loss- and gain-of-function experiments. We found that OSK predominantly bind active somatic enhancers early in reprogramming and immediately initiate their inactivation genome-wide by inducing the redistribution of somatic TFs away from somatic enhancers to sites elsewhere engaged by OSK, recruiting Hdac1, and repressing the somatic TF Fra1. Pluripotency enhancer selection is a stepwise process that also begins early in reprogramming through collaborative binding of OSK at sites with high OSK-motif density. Most pluripotency enhancers are selected later in the process and require OS and other pluripotency TFs. Somatic and pluripotency TFs modulate reprogramming efficiency when overexpressed by altering OSK targeting, somatic-enhancer inactivation, and pluripotency enhancer selection. Together, our data indicate that collaborative interactions among OSK and with stage-specific TFs direct both somatic-enhancer inactivation and pluripotency-enhancer selection to drive reprogramming.
Asunto(s)
Reprogramación Celular , Factores de Transcripción/metabolismo , Animales , Cromatina/metabolismo , Fibroblastos/metabolismo , Código de Histonas , Factor 4 Similar a Kruppel , Factores de Transcripción de Tipo Kruppel/metabolismo , Ratones , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Elementos Reguladores de la Transcripción , Factores de Transcripción SOXB1/metabolismo , Elementos Silenciadores TranscripcionalesRESUMEN
The two oncogenes KRas and Myc cooperate to drive tumorigenesis, but the mechanism underlying this remains unclear. In a mouse lung model of KRasG12D-driven adenomas, we find that co-activation of Myc drives the immediate transition to highly proliferative and invasive adenocarcinomas marked by highly inflammatory, angiogenic, and immune-suppressed stroma. We identify epithelial-derived signaling molecules CCL9 and IL-23 as the principal instructing signals for stromal reprogramming. CCL9 mediates recruitment of macrophages, angiogenesis, and PD-L1-dependent expulsion of T and B cells. IL-23 orchestrates exclusion of adaptive T and B cells and innate immune NK cells. Co-blockade of both CCL9 and IL-23 abrogates Myc-induced tumor progression. Subsequent deactivation of Myc in established adenocarcinomas triggers immediate reversal of all stromal changes and tumor regression, which are independent of CD4+CD8+ T cells but substantially dependent on returning NK cells. We show that Myc extensively programs an immune suppressive stroma that is obligatory for tumor progression.
Asunto(s)
Adenocarcinoma/inmunología , Adenoma/inmunología , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/inmunología , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Adenoma/genética , Adenoma/patología , Animales , Carcinogénesis , Quimiocinas CC/inmunología , Modelos Animales de Enfermedad , Femenino , Inflamación/inmunología , Inflamación/metabolismo , Interleucina-23/inmunología , Neoplasias Pulmonares/patología , Proteínas Inflamatorias de Macrófagos/inmunología , Macrófagos/inmunología , Masculino , Ratones , Microambiente TumoralRESUMEN
Oncogenic activation of MYC in cancers predominantly involves increased transcription rather than coding region mutations. However, MYC-dependent lymphomas frequently acquire point mutations in the MYC phosphodegron, including at threonine 58 (T58), where phosphorylation permits binding via the FBW7 ubiquitin ligase triggering MYC degradation. To understand how T58 phosphorylation functions in normal cell physiology, we introduced an alanine mutation at T58 (T58A) into the endogenous c-Myc locus in the mouse germline. While MYC-T58A mice develop normally, lymphomas and myeloid leukemias emerge in â¼60% of adult homozygous T58A mice. We found that primitive hematopoietic progenitor cells from MYC-T58A mice exhibit aberrant self-renewal normally associated with hematopoietic stem cells (HSCs) and up-regulate a subset of MYC target genes important in maintaining stem/progenitor cell balance. In lymphocytes, genomic occupancy by MYC-T58A was increased at all promoters compared with WT MYC, while genes differentially expressed in a T58A-dependent manner were significantly more proximal to MYC-bound enhancers. MYC-T58A lymphocyte progenitors exhibited metabolic alterations and decreased activation of inflammatory and apoptotic pathways. Our data demonstrate that a single point mutation stabilizing MYC is sufficient to skew target gene expression, producing a profound gain of function in multipotential hematopoietic progenitors associated with self-renewal and initiation of lymphomas and leukemias.
Asunto(s)
Proteína 7 que Contiene Repeticiones F-Box-WD , Neoplasias Hematológicas , Linfoma , Proteínas Proto-Oncogénicas c-myc , Animales , Ratones , Células Germinativas/metabolismo , Células Madre Hematopoyéticas/metabolismo , Mutación Puntual , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteína 7 que Contiene Repeticiones F-Box-WD/metabolismoRESUMEN
Granulomas are immune cell aggregates formed in response to persistent inflammatory stimuli. Granuloma macrophage subsets are diverse and carry varying copy numbers of their genomic information. The molecular programs that control the differentiation of such macrophage populations in response to a chronic stimulus, though critical for disease outcome, have not been defined. Here, we delineate a macrophage differentiation pathway by which a persistent Toll-like receptor (TLR) 2 signal instructs polyploid macrophage fate by inducing replication stress and activating the DNA damage response. Polyploid granuloma-resident macrophages formed via modified cell divisions and mitotic defects and not, as previously thought, by cell-to-cell fusion. TLR2 signaling promoted macrophage polyploidy and suppressed genomic instability by regulating Myc and ATR. We propose that, in the presence of persistent inflammatory stimuli, pathways previously linked to oncogene-initiated carcinogenesis instruct a long-lived granuloma-resident macrophage differentiation program that regulates granulomatous tissue remodeling.
Asunto(s)
Daño del ADN , Granuloma/inmunología , Macrófagos/inmunología , Mycobacterium tuberculosis/inmunología , Animales , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Diferenciación Celular , Proliferación Celular , Humanos , Inflamación/inmunología , Lipoproteínas/inmunología , Ratones , Ratones Endogámicos C57BL , Mitosis , Proteínas Proto-Oncogénicas c-myc/metabolismo , Receptor Toll-Like 2RESUMEN
MYC's key role in oncogenesis and tumor progression has long been established for most human cancers. In melanoma, its deregulated activity by amplification of 8q24 chromosome or by upstream signaling coming from activating mutations in the RAS/RAF/MAPK pathway-the most predominantly mutated pathway in this disease-turns MYC into not only a driver but also a facilitator of melanoma progression, with documented effects leading to an aggressive clinical course and resistance to targeted therapy. Here, by making use of Omomyc, the most characterized MYC inhibitor to date that has just successfully completed a phase I clinical trial, we show for the first time that MYC inhibition in melanoma induces remarkable transcriptional modulation, resulting in severely compromised tumor growth and a clear abrogation of metastatic capacity independently of the driver mutation. By reducing MYC's transcriptional footprint in melanoma, Omomyc elicits gene expression profiles remarkably similar to those of patients with good prognosis, underlining the therapeutic potential that such an approach could eventually have in the clinic in this dismal disease.
Asunto(s)
Melanoma , Humanos , Pronóstico , Melanoma/genética , Transducción de Señal , Carcinogénesis , Transformación Celular Neoplásica , Proteínas Proto-Oncogénicas c-myc/metabolismoRESUMEN
Foxo transcription factors play an essential role in regulating specialized lymphocyte functions and in maintaining T cell quiescence. Here, we used a system in which Foxo1 transcription-factor activity, which is normally terminated upon cell activation, cannot be silenced, and we show that enforcing Foxo1 activity disrupts homeostasis of CD4 conventional and regulatory T cells. Despite limiting cell metabolism, continued Foxo1 activity is associated with increased activation of the kinase Akt and a cell-intrinsic proliferative advantage; however, survival and cell division are decreased in a competitive setting or growth-factor-limiting conditions. Via control of expression of the transcription factor Myc and the IL-2 receptor ß-chain, termination of Foxo1 signaling couples the increase in cellular cholesterol to biomass accumulation after activation, thereby facilitating immunological synapse formation and mTORC1 activity. These data reveal that Foxo1 regulates the integration of metabolic and mitogenic signals essential for T cell competitive fitness and the coordination of cell growth with cell division.
Asunto(s)
Linfocitos T CD4-Positivos/fisiología , Proteína Forkhead Box O1/metabolismo , Linfocitos T Reguladores/fisiología , Animales , Proliferación Celular , Células Cultivadas , Colesterol/metabolismo , Proteína Forkhead Box O1/genética , Perfilación de la Expresión Génica , Homeostasis , Sinapsis Inmunológicas/metabolismo , Subunidad beta del Receptor de Interleucina-2/genética , Subunidad beta del Receptor de Interleucina-2/metabolismo , Activación de Linfocitos , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Ratones , Ratones Noqueados , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Transducción de SeñalRESUMEN
The Myc proto-oncogene has been intensively studied in tumorigenesis and development. A new paper in Cell reports the role of Myc as a determinant of mammalian longevity. Myc heterozygous mice exhibit extended lifespans resulting from alterations in multiple cellular processes distinct from those observed in other longevity models.
Asunto(s)
Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Animales , Femenino , MasculinoRESUMEN
MYC is a highly pleiotropic transcription factor whose deregulation promotes cancer. In contrast, we find that Myc haploinsufficient (Myc(+/-)) mice exhibit increased lifespan. They show resistance to several age-associated pathologies, including osteoporosis, cardiac fibrosis, and immunosenescence. They also appear to be more active, with a higher metabolic rate and healthier lipid metabolism. Transcriptomic analysis reveals a gene expression signature enriched for metabolic and immune processes. The ancestral role of MYC as a regulator of ribosome biogenesis is reflected in reduced protein translation, which is inversely correlated with longevity. We also observe changes in nutrient and energy sensing pathways, including reduced serum IGF-1, increased AMPK activity, and decreased AKT, TOR, and S6K activities. In contrast to observations in other longevity models, Myc(+/-) mice do not show improvements in stress management pathways. Our findings indicate that MYC activity has a significant impact on longevity and multiple aspects of mammalian healthspan.
Asunto(s)
Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Envejecimiento , Animales , Tamaño Corporal , Femenino , Longevidad , Linfoma/genética , Masculino , Redes y Vías Metabólicas , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , TranscriptomaRESUMEN
Telomerase is intimately associated with stem cells and cancer, because it catalytically elongates telomeres-nucleoprotein caps that protect chromosome ends1. Overexpression of telomerase reverse transcriptase (TERT) enhances the proliferation of cells in a telomere-independent manner2-8, but so far, loss-of-function studies have provided no evidence that TERT has a direct role in stem cell function. In many tissues, homeostasis is shaped by stem cell competition, a process in which stem cells compete on the basis of inherent fitness. Here we show that conditional deletion of Tert in the spermatogonial stem cell (SSC)-containing population in mice markedly impairs competitive clone formation. Using lineage tracing from the Tert locus, we find that TERT-expressing SSCs yield long-lived clones, but that clonal inactivation of TERT promotes stem cell differentiation and a genome-wide reduction in open chromatin. This role for TERT in competitive clone formation occurs independently of both its reverse transcriptase activity and the canonical telomerase complex. Inactivation of TERT causes reduced activity of the MYC oncogene, and transgenic expression of MYC in the TERT-deleted pool of SSCs efficiently rescues clone formation. Together, these data reveal a catalytic-activity-independent requirement for TERT in enhancing stem cell competition, uncover a genetic connection between TERT and MYC and suggest that a selective advantage for stem cells with high levels of TERT contributes to telomere elongation in the male germline during homeostasis and ageing.
Asunto(s)
Competencia Celular , Células Clonales , Células Madre , Telomerasa , Animales , Masculino , Ratones , Diferenciación Celular , Linaje de la Célula , Cromatina/metabolismo , Cromatina/genética , Células Clonales/citología , Células Clonales/enzimología , Células Clonales/metabolismo , Eliminación de Gen , Genes myc , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Espermatogonias/citología , Espermatogonias/metabolismo , Células Madre/citología , Células Madre/enzimología , Células Madre/metabolismo , Telomerasa/deficiencia , Telomerasa/genética , Telomerasa/metabolismo , Transcripción Reversa , Biocatálisis , Homeostasis , EnvejecimientoRESUMEN
High-intensity transcription and replication supercoil DNA to levels that can impede or halt these processes. As a potent transcription amplifier and replication accelerator, the proto-oncogene MYC must manage this interfering torsional stress. By comparing gene expression with the recruitment of topoisomerases and MYC to promoters, we surmised a direct association of MYC with topoisomerase 1 (TOP1) and TOP2 that was confirmed in vitro and in cells. Beyond recruiting topoisomerases, MYC directly stimulates their activities. We identify a MYC-nucleated "topoisome" complex that unites TOP1 and TOP2 and increases their levels and activities at promoters, gene bodies, and enhancers. Whether TOP2A or TOP2B is included in the topoisome is dictated by the presence of MYC versus MYCN, respectively. Thus, in vitro and in cells, MYC assembles tools that simplify DNA topology and promote genome function under high output conditions.
Asunto(s)
ADN-Topoisomerasas de Tipo II/metabolismo , Neoplasias/enzimología , Proteínas de Unión a Poli-ADP-Ribosa/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , Transcripción Genética , Animales , Replicación del ADN , ADN-Topoisomerasas de Tipo I/genética , ADN-Topoisomerasas de Tipo I/metabolismo , ADN-Topoisomerasas de Tipo II/genética , ADN de Neoplasias/biosíntesis , ADN de Neoplasias/genética , ADN Superhelicoidal/biosíntesis , ADN Superhelicoidal/genética , Activación Enzimática , Regulación Neoplásica de la Expresión Génica , Células HCT116 , Humanos , Células K562 , Complejos Multienzimáticos , Neoplasias/genética , Neoplasias/patología , Proteínas de Unión a Poli-ADP-Ribosa/genética , Regiones Promotoras Genéticas , Unión Proteica , Proteínas Proto-Oncogénicas c-myc/genética , RatasRESUMEN
Non-covalent complexes of glycolytic enzymes, called metabolons, were postulated in the 1970s, but the concept has been controversial. Here we show that a c-Myc-responsive long noncoding RNA (lncRNA) that we call glycoLINC (gLINC) acts as a backbone for metabolon formation between all four glycolytic payoff phase enzymes (PGK1, PGAM1, ENO1, and PKM2) along with lactate dehydrogenase A (LDHA). The gLINC metabolon enhances glycolytic flux, increases ATP production, and enables cell survival under serine deprivation. Furthermore, gLINC overexpression in cancer cells promotes xenograft growth in mice fed a diet deprived of serine, suggesting that cancer cells employ gLINC during metabolic reprogramming. We propose that gLINC makes a functional contribution to cancer cell adaptation and provide the first example of a lncRNA-facilitated metabolon.
Asunto(s)
Biomarcadores de Tumor/metabolismo , Proteínas Portadoras/metabolismo , Proteínas de Unión al ADN/metabolismo , Glucólisis , Proteínas de la Membrana/metabolismo , Neoplasias/enzimología , Fosfoglicerato Quinasa/metabolismo , Fosfoglicerato Mutasa/metabolismo , Fosfopiruvato Hidratasa/metabolismo , ARN Largo no Codificante/metabolismo , Hormonas Tiroideas/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Biomarcadores de Tumor/genética , Proteínas Portadoras/genética , Proliferación Celular , Proteínas de Unión al ADN/genética , Femenino , Regulación Enzimológica de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Células HEK293 , Células HeLa , Células Hep G2 , Humanos , L-Lactato Deshidrogenasa/genética , L-Lactato Deshidrogenasa/metabolismo , Proteínas de la Membrana/genética , Ratones Desnudos , Complejos Multienzimáticos , Neoplasias/genética , Neoplasias/patología , Fosfoglicerato Quinasa/genética , Fosfoglicerato Mutasa/genética , Fosfopiruvato Hidratasa/genética , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , ARN Largo no Codificante/genética , Serina/deficiencia , Hormonas Tiroideas/genética , Carga Tumoral , Proteínas Supresoras de Tumor/genética , Proteínas de Unión a Hormona TiroideRESUMEN
T lymphocytes and B lymphocytes integrate activating signals to control the size of their proliferative response. Here we report that such control was achieved by timed changes in the production rate of cell-cycle-regulating proto-oncoprotein Myc, with division cessation occurring when Myc levels fell below a critical threshold. The changing pattern of the level of Myc was not affected by cell division, which identified the regulating mechanism as a cell-intrinsic, heritable temporal controller. Overexpression of Myc in stimulated T cells and B cells did not sustain cell proliferation indefinitely, as a separate 'time-to-die' mechanism, also heritable, was programmed after lymphocyte activation and led to eventual cell loss. Together the two competing cell-intrinsic timed fates created the canonical T cell and B cell immune-response pattern of rapid growth followed by loss of most cells. Furthermore, small changes in these timed processes by regulatory signals, or by oncogenic transformation, acted in synergy to greatly enhance cell numbers over time.