RESUMEN
Pancreatic acinar cells rely on PTF1 and other transcription factors to deploy their transcriptional program. We identify NFIC as a NR5A2 interactor and regulator of acinar differentiation. NFIC binding sites are enriched in NR5A2 ChIP-Sequencing peaks. Nfic knockout mice have a smaller, histologically normal, pancreas with reduced acinar gene expression. NFIC binds and regulates the promoters of acinar genes and those involved in RNA/protein metabolism, and Nfic knockout pancreata show defective ribosomal RNA maturation. NFIC dampens the endoplasmic reticulum stress program through binding to gene promoters and is required for resolution of Tunicamycin-mediated stress. NFIC is down-regulated during caerulein pancreatitis and is required for recovery after damage. Normal human pancreata with low levels of NFIC transcripts display reduced expression of genes down-regulated in Nfic knockout mice. NFIC expression is down-regulated in mouse and human pancreatic ductal adenocarcinoma. Consistently, Nfic knockout mice develop a higher number of mutant Kras-driven pre-neoplastic lesions.
Asunto(s)
Carcinoma Ductal Pancreático , Factores de Transcripción NFI , Neoplasias Pancreáticas , Ribosomas , Animales , Humanos , Ratones , Células Acinares/metabolismo , Carcinoma Ductal Pancreático/patología , Ratones Noqueados , Factores de Transcripción NFI/metabolismo , Páncreas/metabolismo , Neoplasias Pancreáticas/patologíaRESUMEN
Bladder cancer is a highly prevalent tumor, requiring the urgent development of novel therapies, especially for locally advanced and metastatic disease. Nintedanib is a potent antifibrotic angio-kinase inhibitor, which has shown clinical efficacy in combination with chemotherapy in patients with locally advanced muscle-invasive bladder cancer. Nintedanib inhibits fibroblast growth factor receptors (FGFRs), validated targets in patients with bladder cancer harboring FGFR3/2 genetic alterations. Here, we aimed at studying its mechanisms of action to understand therapy resistance, identify markers predictive of response, and improve the design of future clinical trials. We have used a panel of genetically well-characterized human bladder cancer cells to identify the molecular and transcriptomic changes induced upon treatment with nintedanib, in vitro and in vivo, at the tumor and stroma cell levels. We showed that bladder cancer cells display an intrinsic resistance to nintedanib treatment in vitro, independently of their FGFR3 status. However, nintedanib has higher antitumor activity on mouse xenografts. We have identified PI3K activation as a resistance mechanism against nintedanib in bladder cancer and evidenced that the combination of nintedanib with the PI3K inhibitor alpelisib has synergistic antitumor activity. Treatment with this combination is associated with cell-cycle inhibition at the tumoral and stromal levels and potent nontumor cell autonomous effects on α-smooth muscle actin-positive tumor infiltrating cells and tumor vasculature. The combination of nintedanib with PI3K inhibitors not only reversed bladder cancer resistance to nintedanib but also enhanced its antiangiogenic effects.
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Neoplasias Pulmonares , Neoplasias de la Vejiga Urinaria , Humanos , Ratones , Animales , Fosfatidilinositol 3-Quinasas/uso terapéutico , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias de la Vejiga Urinaria/tratamiento farmacológico , Neoplasias de la Vejiga Urinaria/genética , Células del Estroma , Línea Celular TumoralRESUMEN
BACKGROUND: VCN-01 is an oncolytic adenovirus (Ad5 based) designed to replicate in cancer cells with dysfunctional RB1 pathway, express hyaluronidase to enhance virus intratumoral spread and facilitate chemotherapy and immune cells extravasation into the tumor. This phase I clinical trial was aimed to find the maximum tolerated dose/recommended phase II dose (RP2D) and dose-limiting toxicity (DLT) of the intravenous delivery of the replication-competent VCN-01 adenovirus in patients with advanced cancer. METHODS: Part I: patients with advanced refractory solid tumors received one single dose of VCN-01. Parts II and III: patients with pancreatic adenocarcinoma received VCN-01 (only in cycle 1) and nab-paclitaxel plus gemcitabine (VCN-concurrent on day 1 in Part II, and 7 days before chemotherapy in Part III). Patients were required to have anti-Ad5 neutralizing antibody (NAbs) titers lower than 1/350 dilution. Pharmacokinetic and pharmacodynamic analyses were performed. RESULTS: 26% of the patients initially screened were excluded based on high NAbs levels. Sixteen and 12 patients were enrolled in Part I and II, respectively: RP2D were 1×1013 viral particles (vp)/patient (Part I), and 3.3×1012 vp/patient (Part II). Fourteen patients were included in Part III: there were no DLTs and the RP2D was 1×1013 vp/patient. Observed DLTs were grade 4 aspartate aminotransferase increase in one patient (Part I, 1×1013 vp), grade 4 febrile neutropenia in one patient and grade 5 thrombocytopenia plus enterocolitis in another patient (Part II, 1×1013 vp). In patients with pancreatic adenocarcinoma overall response rate were 50% (Part II) and 50% (Part III). VCN-01 viral genomes were detected in tumor tissue in five out of six biopsies (day 8). A second viral plasmatic peak and increased hyaluronidase serum levels suggested replication after intravenous injection in all patients. Increased levels of immune biomarkers (interferon-γ, soluble lymphocyte activation gene-3, interleukin (IL)-6, IL-10) were found after VCN-01 administration. CONCLUSIONS: Treatment with VCN-01 is feasible and has an acceptable safety. Encouraging biological and clinical activity was observed when administered in combination with nab-paclitaxel plus gemcitabine to patients with pancreatic adenocarcinoma. TRIAL REGISTRATION NUMBER: NCT02045602.
Asunto(s)
Adenocarcinoma , Neoplasias Pancreáticas , Adenocarcinoma/patología , Adenoviridae/genética , Albúminas , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Desoxicitidina/análogos & derivados , Humanos , Hialuronoglucosaminidasa/uso terapéutico , Paclitaxel , Neoplasias Pancreáticas/tratamiento farmacológico , Gemcitabina , Neoplasias PancreáticasRESUMEN
Social cognition is progressively acquired from childhood to early adulthood. Nevertheless there is a shortage of social cognition scales with normative data for Spanish children and adolescents. Social Attribution Task-Multiple Choice (SAT-MC) and its alternate version SAT-MC-II are social cognition instruments that measure mentalization skills in adults with psychosis. This study aimed to report psycho- metric characteristics and normative data of the Spanish version of SAT-MC and SAT-MC-II in a sample of minors.
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Trastornos Psicóticos , Percepción Social , Adolescente , Adulto , Niño , Humanos , Pruebas Neuropsicológicas , Reproducibilidad de los ResultadosRESUMEN
Cystic neoplasms of the pancreas are an increasingly important public health problem. The majority of these lesions are benign but some progress to invasive pancreatic ductal adenocarcinoma (PDAC). There is a dearth of mouse models of these conditions. The orphan nuclear receptor NR5A2 regulates development, differentiation, and inflammation. Germline Nr5a2 heterozygosity sensitizes mice to the oncogenic effects of mutant Kras in the pancreas. Here, we show that - unlike constitutive Nr5a2+/- mice - conditional Nr5a2 heterozygosity in pancreatic epithelial cells, combined with mutant Kras (KPN+/- ), leads to a dramatic replacement of the pancreatic parenchyma with cystic structures and an accelerated development of high-grade PanINs and PDAC. Timed histopathological analyses indicated that in KPN+/- mice PanINs precede the formation of cystic lesions and the latter precede PDAC. A single episode of acute caerulein pancreatitis is sufficient to accelerate the development of cystic lesions in KPN+/- mice. Epithelial cells of cystic lesions of KPN+/- mice express MUC1, MUC5AC, and MUC6, but lack expression of MUC2, CDX2, and acinar markers, indicative of a pancreato-biliary/gastric phenotype. In accordance with this, in human samples we found a non-significantly decreased expression of NR5A2 in mucinous tumours, compared with conventional PDAC. These results highlight that the effects of loss of one Nr5a2 allele are time- and cell context-dependent. KPN+/- mice represent a new model to study the formation of cystic pancreatic lesions and their relationship with PanINs and classical PDAC. Our findings suggest that pancreatitis could also contribute to acceleration of cystic tumour progression in patients. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Asunto(s)
Carcinoma Ductal Pancreático/patología , Neoplasias Pancreáticas/patología , Receptores Citoplasmáticos y Nucleares/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Animales , Carcinoma Ductal Pancreático/genética , Progresión de la Enfermedad , Células Epiteliales/patología , Femenino , Heterocigoto , Humanos , Masculino , Ratones , Persona de Mediana Edad , Quiste Pancreático/patología , Conductos Pancreáticos/patología , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Receptores Citoplasmáticos y Nucleares/genéticaRESUMEN
Defects in transcriptional regulators of pancreatic exocrine differentiation have been implicated in pancreatic tumorigenesis, but the molecular mechanisms are poorly understood. The locus encoding the transcription factor HNF1A harbors susceptibility variants for pancreatic ductal adenocarcinoma (PDAC), while KDM6A, encoding Lysine-specific demethylase 6A, carries somatic mutations in PDAC. Here, we show that pancreas-specific Hnf1a null mutant transcriptomes phenocopy those of Kdm6a mutations, and both defects synergize with KrasG12D to cause PDAC with sarcomatoid features. We combine genetic, epigenomic, and biochemical studies to show that HNF1A recruits KDM6A to genomic binding sites in pancreatic acinar cells. This remodels the acinar enhancer landscape, activates differentiated acinar cell programs, and indirectly suppresses oncogenic and epithelial-mesenchymal transition genes. We also identify a subset of non-classical PDAC samples that exhibit the HNF1A/KDM6A-deficient molecular phenotype. These findings provide direct genetic evidence that HNF1A deficiency promotes PDAC. They also connect the tumor-suppressive role of KDM6A deficiency with a cell-specific molecular mechanism that underlies PDAC subtype definition.
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Células Acinares/metabolismo , Carcinoma Ductal Pancreático/genética , Factor Nuclear 1-alfa del Hepatocito/genética , Histona Demetilasas/genética , Neoplasias Pancreáticas/genética , Animales , Carcinoma Ductal Pancreático/metabolismo , Epigénesis Genética , Regulación Neoplásica de la Expresión Génica , Redes Reguladoras de Genes , Factor Nuclear 1-alfa del Hepatocito/metabolismo , Histona Demetilasas/metabolismo , Humanos , Ratones , Mutación , Especificidad de Órganos , Páncreas/metabolismo , Neoplasias Pancreáticas/metabolismoRESUMEN
Among malignant mesotheliomas (MM), the sarcomatoid subtype is associated with higher chemoresistance and worst survival. Due to its low incidence, there has been little progress in the knowledge of the molecular mechanisms associated with sarcomatoid MM, which might help to define novel therapeutic targets. In this work, we show that loss of PTEN expression is frequent in human sarcomatoid MM and PTEN expression levels are lower in sarcomatoid MM than in the biphasic and epithelioid subtypes. Combined Pten and Trp53 deletion in mouse mesothelium led to nonepithelioid MM development. In Pten;Trp53-null mice developing MM, the Gαi2-coupled receptor subunit activated MEK/ERK and PI3K, resulting in aggressive, immune-suppressed tumors. Combined inhibition of MEK and p110ß/PI3K reduced mouse tumor cell growth in vitro. Therapeutic inhibition of MEK and p110ß/PI3K using selumetinib (AZD6244, ARRY-142886) and AZD8186, two drugs that are currently in clinical trials, increased the survival of Pten;Trp53-null mice without major toxicity. This drug combination effectively reduced the proliferation of primary cultures of human pleural (Pl) MM, implicating nonepithelioid histology and high vimentin, AKT1/2, and Gαi2 expression levels as predictive markers of response to combined MEK and p110ß/PI3K inhibition. Our findings provide a rationale for the use of selumetinib and AZD8186 in patients with MM with sarcomatoid features. This constitutes a novel targeted therapy for a poor prognosis and frequently chemoresistant group of patients with MM, for whom therapeutic options are currently lacking. SIGNIFICANCE: Mesothelioma is highly aggressive; its sarcomatoid variants have worse prognosis. Building on a genetic mouse model, a novel combination therapy is uncovered that is relevant to human tumors.
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Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Fosfatidilinositol 3-Quinasa Clase I/antagonistas & inhibidores , Neoplasias Pulmonares/tratamiento farmacológico , Mesotelioma/tratamiento farmacológico , Quinasas de Proteína Quinasa Activadas por Mitógenos/antagonistas & inhibidores , Neoplasias Peritoneales/tratamiento farmacológico , Neoplasias Pleurales/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Compuestos de Anilina/farmacología , Compuestos de Anilina/uso terapéutico , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Bencimidazoles/farmacología , Bencimidazoles/uso terapéutico , Proliferación Celular/efectos de los fármacos , Cromonas/farmacología , Cromonas/uso terapéutico , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Modelos Animales de Enfermedad , Epitelio/patología , Femenino , Técnicas de Sustitución del Gen , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Mesotelioma/genética , Mesotelioma/patología , Mesotelioma Maligno , Ratones , Ratones Noqueados , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Terapia Molecular Dirigida/métodos , Fosfohidrolasa PTEN/genética , Neoplasias Peritoneales/genética , Neoplasias Peritoneales/patología , Peritoneo/patología , Pleura/patología , Neoplasias Pleurales/genética , Neoplasias Pleurales/patología , Cultivo Primario de Células , Pronóstico , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteína p53 Supresora de Tumor/genéticaRESUMEN
OBJECTIVE: Reduced performance in several cognitive domains has been repeatedly related to hepatitis C virus (HCV). Nevertheless, there is no consensus about the severity or cognitive profile. Moreover, other possible influential variables are scarcely controlled. The aim of this study is to define the specific cognitive profile in HCV after controlling for confounding variables. METHODS: Forty-two HCV patients were distributed in 2groups according to the presence of co-infection with human immunodeficiency virus; a third group with 22 healthy controls was also included. The neuropsychological assessment included tests that assess processing speed, executive functioning, verbal memory, visual memory and working memory. Measures of depression (BDI), anxiety (HAM-A), fatigue (MAF), anhedonia (PAS), insomnia (ISI), quality of life (SF-36) and history of drug abuse (DAST-20) were taken in order to explore differences among groups and to control for their possible influence on cognitive performance. RESULTS: HCV patients (including human immunodeficiency virus-coinfection) performed significantly worse in all cognitive measures. However, when the effect of BDI, HAM-A, MAF, ISI, SF-36 & DAST-20 was controlled, only verbal memory of HCV patients differed among groups. Coinfected patients performed worse in verbal memory. CONCLUSIONS: According to previous studies verbal memory is the unique cognitive domain related to the effect of HCV. The present study does not support that the neurovirulence effect of HCV is decreasing cognitive performance in HCV patients. Nevertheless, the present study cannot relate the fronto-striatal disruption with the cognitive performance in HCV patients.
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Trastornos del Conocimiento/virología , Hepacivirus , Hepatitis C/psicología , Calidad de Vida , Adulto , Anhedonia , Ansiedad/diagnóstico , Estudios de Casos y Controles , Depresión/diagnóstico , Función Ejecutiva , Fatiga/diagnóstico , Femenino , Infecciones por VIH/psicología , Humanos , Masculino , Memoria , Persona de Mediana Edad , Análisis Multivariante , Pruebas Neuropsicológicas , Trastornos del Inicio y del Mantenimiento del Sueño/diagnóstico , Factores Socioeconómicos , Trastornos Relacionados con Sustancias/diagnósticoRESUMEN
Chronic inflammation increases the risk of developing one of several types of cancer. Inflammatory responses are currently thought to be controlled by mechanisms that rely on transcriptional networks that are distinct from those involved in cell differentiation. The orphan nuclear receptor NR5A2 participates in a wide variety of processes, including cholesterol and glucose metabolism in the liver, resolution of endoplasmic reticulum stress, intestinal glucocorticoid production, pancreatic development and acinar differentiation. In genome-wide association studies, single nucleotide polymorphisms in the vicinity of NR5A2 have previously been associated with the risk of pancreatic adenocarcinoma. In mice, Nr5a2 heterozygosity sensitizes the pancreas to damage, impairs regeneration and cooperates with mutant Kras in tumour progression. Here, using a global transcriptomic analysis, we describe an epithelial-cell-autonomous basal pre-inflammatory state in the pancreas of Nr5a2+/- mice that is reminiscent of the early stages of pancreatitis-induced inflammation and is conserved in histologically normal human pancreases with reduced expression of NR5A2 mRNA. In Nr5a2+/-mice, NR5A2 undergoes a marked transcriptional switch, relocating from differentiation-specific to inflammatory genes and thereby promoting gene transcription that is dependent on the AP-1 transcription factor. Pancreatic deletion of Jun rescues the pre-inflammatory phenotype, as well as binding of NR5A2 to inflammatory gene promoters and the defective regenerative response to damage. These findings support the notion that, in the pancreas, the transcriptional networks involved in differentiation-specific functions also suppress inflammatory programmes. Under conditions of genetic or environmental constraint, these networks can be subverted to foster inflammation.
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Diferenciación Celular/genética , Regulación de la Expresión Génica , Inflamación/genética , Páncreas/metabolismo , Páncreas/patología , Receptores Citoplasmáticos y Nucleares/metabolismo , Transcriptoma , Células Acinares/metabolismo , Células Acinares/patología , Animales , Cromatina/genética , Cromatina/metabolismo , Células Epiteliales/metabolismo , Células Epiteliales/patología , Redes Reguladoras de Genes/genética , Genes jun/genética , Heterocigoto , Humanos , Ratones , Especificidad de Órganos/genética , Pancreatitis/genética , Regiones Promotoras Genéticas/genética , Receptores Citoplasmáticos y Nucleares/deficiencia , Receptores Citoplasmáticos y Nucleares/genética , Factor de Transcripción AP-1/metabolismoRESUMEN
BACKGROUND AND AIMS: c-Myc is highly expressed in pancreatic multipotent progenitor cells (MPC) and in pancreatic cancer. The transition from MPC to unipotent acinar progenitors is associated with c-Myc downregulation; a role for c-Myc in this process, and its possible relationship to a role in cancer, has not been established. DESIGN: Using coimmunoprecipitation assays, we demonstrate that c-Myc and Ptf1a interact. Using reverse transcriptase qPCR, western blot and immunofluorescence, we show the erosion of the acinar programme. To analyse the genomic distribution of c-Myc and Ptf1a and the global transcriptomic profile, we used ChIP-seq and RNA-seq, respectively; validation was performed with ChIP-qPCR and RT-qPCR. Lineage-tracing experiments were used to follow the effect of c-Myc overexpression in preacinar cells on acinar differentiation. RESULTS: c-Myc binds and represses the transcriptional activity of Ptf1a. c-Myc overexpression in preacinar cells leads to a massive erosion of differentiation. In adult Ela1-Myc mice: (1) c-Myc binds to Ptf1a, and Tcf3 is downregulated; (2) Ptf1a and c-Myc display partially overlapping chromatin occupancy but do not bind the same E-boxes; (3) at the proximal promoter of genes coding for digestive enzymes, we find reduced PTF1 binding and increased levels of repressive chromatin marks and PRC2 complex components. Lineage tracing of committed acinar precursors reveals that c-Myc overexpression does not restore multipotency but allows the persistence of a preacinar-like cell population. In addition, mutant KRas can lead to c-Myc overexpression and acinar dysregulation. CONCLUSIONS: c-Myc repression during development is crucial for the maturation of preacinar cells, and c-Myc overexpression can contribute to pancreatic carcinogenesis through the induction of a dedifferentiated state.
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Células Acinares/metabolismo , Regulación hacia Abajo/genética , Homeostasis , Páncreas/metabolismo , Neoplasias Pancreáticas/genética , Proteínas Proto-Oncogénicas c-myc/genética , Animales , Diferenciación Celular , Modelos Animales de Enfermedad , Homeostasis/genética , Ratones , Factores de Transcripción/genéticaRESUMEN
OBJECTIVES: We hypothesize that time perception and executive functions are interrelated and share neuroanatomical basis, and that fluctuations in levels of cognitive effort play a role in mediating that relation. The main goal of this study was to identify brain structures activated both by increases in cognitive activity and during time perception tasks. METHODS: We performed a multimodal meta-analysis to identify common brain regions in the findings of (a) an SDM meta-analysis of neuroimaging studies assessing the brain response to increasing levels of cognitive difficulty, and (b) an ALE meta-analysis on neuroimaging of time perception (Ortuño, Guillén-Grima, López-García, Gómez, & Pla, 2011. Schizophr. Res., 125(2-3), 129-35). RESULTS AND CONCLUSIONS: Consistent with results of previous, separate meta-analyses, the current study supports the hypothesis that there exists a group of brain regions engaged both in time perception tasks and during tasks requiring cognitive effort. Thus, brain regions associated with working memory and executive functions were found to be engaged during time estimation tasks, and regions associated with time perception were found to be engaged by an increase in the difficulty of non-temporal tasks. The implication is that temporal perception and cognitive processes demanding cognitive control become interlinked when there is an increase in the level of cognitive effort demanded.
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Mapeo Encefálico , Encéfalo/fisiología , Cognición/fisiología , Función Ejecutiva/fisiología , Percepción del Tiempo/fisiología , Humanos , Imagen por Resonancia Magnética , Tomografía de Emisión de PositronesRESUMEN
OBJECTIVES: Nr5a2 participates in biliary acid metabolism and is a major regulator of the pancreatic exocrine programme. Single nucleotide polymorphisms in the vicinity of NR5A2 are associated with the risk of pancreatic ductal adenocarcinoma (PDAC). AIMS: To determine the role of Nr5a2 in pancreatic homeostasis, damage-induced regeneration and mutant KRas-driven pancreatic tumourigenesis. DESIGN: Nr5a2+/- and KRas(G12V);Ptf1a-Cre;Nr5a2+/- mice were used to investigate whether a full dose of Nr5a2 is required for normal pancreas development, recovery from caerulein-induced pancreatitis, and protection from tumour development. RESULTS: Adult Nr5a2+/- mice did not display histological abnormalities in the pancreas but showed a more severe acute pancreatitis, increased acino-ductal metaplasia and impaired recovery from damage. This was accompanied by increased myeloid cell infiltration and proinflammatory cytokine gene expression, and hyperactivation of nuclear factor κb and signal transducer and activator of transcription 3 signalling pathways. Induction of multiple episodes of acute pancreatitis was associated with more severe damage and delayed regeneration. Inactivation of one Nr5a2 allele selectively in pancreatic epithelial cells was sufficient to cause impaired recovery from pancreatitis. In comparison with Nr5a2+/+ mice, KRas(G12V);Ptf1a(Cre/+);Nr5a2+/- mice showed a non-statistically significant increase in the area affected by preneoplastic lesions. However, a single episode of acute pancreatitis cooperated with loss of one Nr5a2 allele to accelerate KRas(G12V)-driven development of preneoplastic lesions. CONCLUSIONS: A full Nr5a2 dose is required to restore pancreatic homeostasis upon damage and to suppress the KRas(G12V)-driven mouse pancreatic intraepithelial neoplasia progression, indicating that Nr5a2 is a novel pancreatic tumour suppressor. Nr5a2 could contribute to PDAC through a role in the recovery from pancreatitis-induced damage.
Asunto(s)
Neoplasias Pancreáticas/genética , Pancreatitis/genética , Proteínas Proto-Oncogénicas p21(ras)/genética , Receptores Citoplasmáticos y Nucleares/genética , Animales , Western Blotting , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/fisiopatología , Ceruletida/farmacología , Heterocigoto , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos , Ratones Noqueados , FN-kappa B/fisiología , Neoplasias Pancreáticas/etiología , Neoplasias Pancreáticas/fisiopatología , Pancreatitis/inducido químicamente , Pancreatitis/fisiopatología , Reacción en Cadena de la Polimerasa , Proteínas Proto-Oncogénicas p21(ras)/fisiología , Receptores Citoplasmáticos y Nucleares/fisiología , Factor de Transcripción STAT3/fisiología , Transducción de Señal/fisiologíaRESUMEN
OBJECTIVES: Previous studies have suggested an important role of the transcription factor Gata6 in endocrine pancreas, while GATA6 haploinsufficient inactivating mutations cause pancreatic agenesis in humans. We aimed to analyse the effects of Gata6 inactivation on pancreas development and function. DESIGN: We deleted Gata6 in all epithelial cells in the murine pancreas at the onset of its development. Acinar proliferation, apoptosis, differentiation and exocrine functions were assessed using reverse transcriptase quantitative PCR (RT-qPCR), chromatin immunoprecipitation, immunohistochemistry and enzyme assays. Adipocyte transdifferentiation was assessed using electron microscopy and genetic lineage tracing. RESULTS: Gata6 is expressed in all epithelial cells in the adult mouse pancreas but it is only essential for exocrine pancreas homeostasis: while dispensable for pancreatic development after e10.5, it is required for complete acinar differentiation, for establishment of polarity and for the maintenance of acinar cells in the adult. Gata6 regulates directly the promoter of genes coding for digestive enzymes and the transcription factors Rbpjl and Mist1. Upon pancreas-selective Gata6 inactivation, massive loss of acinar cells and fat replacement take place. This is accompanied by increased acinar apoptosis and proliferation, acinar-to-ductal metaplasia and adipocyte transdifferentiation. By contrast, the endocrine pancreas is spared. CONCLUSIONS: Our data show that Gata6 is required for the complete differentiation of acinar cells through multiple transcriptional regulatory mechanisms. In addition, it is required for the maintenance of the adult acinar cell compartment. Our studies suggest that GATA6 alterations may contribute to diseases of the human adult exocrine pancreas.
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Células Acinares/citología , Factor de Transcripción GATA6/fisiología , Páncreas Exocrino/citología , Células Acinares/patología , Células Acinares/fisiología , Animales , Apoptosis/fisiología , Diferenciación Celular/fisiología , Proliferación Celular , Femenino , Factor de Transcripción GATA6/deficiencia , Factor de Transcripción GATA6/genética , Eliminación de Gen , Masculino , Metaplasia/genética , Metaplasia/patología , Ratones , Ratones Noqueados , Páncreas Exocrino/crecimiento & desarrollo , Páncreas Exocrino/patología , Páncreas Exocrino/fisiologíaRESUMEN
Humans with heterozygous loss-of-function mutations in the hepatocyte nuclear factor-1alpha (HNF1alpha) gene develop beta-cell-deficient diabetes (maturity-onset diabetes of the young type 3), indicating that HNF1alpha gene dosage is critical in beta-cells. However, whether increased HNF1alpha expression might be beneficial or deleterious for beta-cells is unknown. Furthermore, although it is clear that HNF1alpha is required for beta-cell function, it is not known whether this role is cell autonomous or whether there is a restricted developmental time frame for HNF1alpha to elicit gene activation in beta-cells. To address this, we generated a tetracycline-inducible mouse model that transcribes HNF1alpha selectively in beta-cells in either wild-type or Hnf1alpha-null backgrounds. Short-term induction of HNF1alpha in islets from adult Hnf1alpha(-/-) mice that did not express HNF1alpha throughout development resulted in the activation of target genes, indicating that HNF1alpha has beta-cell-autonomous functions that can be rescued postnatally. However, transgenic induction throughout development, which inevitably resulted in supraphysiological levels of HNF1alpha, strikingly caused a severe reduction of cellular proliferation, increased apoptosis, and consequently beta-cell depletion and diabetes. Thus, HNF1alpha is sensitive to both reduced and excessive concentrations in beta-cells. This finding illustrates the paramount importance of using the correct concentration of a beta-cell transcription factor in both gene therapy and artificial differentiation strategies.