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1.
Cell ; 174(3): 744-757.e24, 2018 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-29887377

RESUMEN

Eukaryotic genomes are packaged into a 3-dimensional structure in the nucleus. Current methods for studying genome-wide structure are based on proximity ligation. However, this approach can fail to detect known structures, such as interactions with nuclear bodies, because these DNA regions can be too far apart to directly ligate. Accordingly, our overall understanding of genome organization remains incomplete. Here, we develop split-pool recognition of interactions by tag extension (SPRITE), a method that enables genome-wide detection of higher-order interactions within the nucleus. Using SPRITE, we recapitulate known structures identified by proximity ligation and identify additional interactions occurring across larger distances, including two hubs of inter-chromosomal interactions that are arranged around the nucleolus and nuclear speckles. We show that a substantial fraction of the genome exhibits preferential organization relative to these nuclear bodies. Our results generate a global model whereby nuclear bodies act as inter-chromosomal hubs that shape the overall packaging of DNA in the nucleus.


Asunto(s)
Núcleo Celular/ultraestructura , Mapeo Cromosómico/métodos , Cromosomas/fisiología , Nucléolo Celular , Núcleo Celular/fisiología , Cromosomas/genética , ADN/fisiología , Eucariontes , Genoma/genética , Genoma/fisiología , Humanos , Relación Estructura-Actividad
2.
Nature ; 627(8002): 196-203, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38355805

RESUMEN

It is well established that neutrophils adopt malleable polymorphonuclear shapes to migrate through narrow interstitial tissue spaces1-3. However, how polymorphonuclear structures are assembled remains unknown4. Here we show that in neutrophil progenitors, halting loop extrusion-a motor-powered process that generates DNA loops by pulling in chromatin5-leads to the assembly of polymorphonuclear genomes. Specifically, we found that in mononuclear neutrophil progenitors, acute depletion of the loop-extrusion loading factor nipped-B-like protein (NIPBL) induced the assembly of horseshoe, banded, ringed and hypersegmented nuclear structures and led to a reduction in nuclear volume, mirroring what is observed during the differentiation of neutrophils. Depletion of NIPBL also induced cell-cycle arrest, activated a neutrophil-specific gene program and conditioned a loss of interactions across topologically associating domains to generate a chromatin architecture that resembled that of differentiated neutrophils. Removing NIPBL resulted in enrichment for mega-loops and interchromosomal hubs that contain genes associated with neutrophil-specific enhancer repertoires and an inflammatory gene program. On the basis of these observations, we propose that in neutrophil progenitors, loop-extrusion programs produce lineage-specific chromatin architectures that permit the packing of chromosomes into geometrically confined lobular structures. Our data also provide a blueprint for the assembly of polymorphonuclear structures, and point to the possibility of engineering de novo nuclear shapes to facilitate the migration of effector cells in densely populated tumorigenic environments.


Asunto(s)
Movimiento Celular , Forma del Núcleo Celular , Neutrófilos , Puntos de Control del Ciclo Celular , Proteínas de Ciclo Celular/deficiencia , Proteínas de Ciclo Celular/metabolismo , Cromatina/química , Cromatina/metabolismo , Cromosomas/química , Cromosomas/metabolismo , Neutrófilos/citología , Neutrófilos/metabolismo , Conformación de Ácido Nucleico , Diferenciación Celular/genética , Inflamación/genética , Elementos de Facilitación Genéticos , Linaje de la Célula/genética
3.
Genes Dev ; 31(10): 973-989, 2017 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-28607179

RESUMEN

Developmental and lineage plasticity have been observed in numerous malignancies and have been correlated with tumor progression and drug resistance. However, little is known about the molecular mechanisms that enable such plasticity to occur. Here, we describe the function of the plant homeodomain finger protein 6 (PHF6) in leukemia and define its role in regulating chromatin accessibility to lineage-specific transcription factors. We show that loss of Phf6 in B-cell leukemia results in systematic changes in gene expression via alteration of the chromatin landscape at the transcriptional start sites of B-cell- and T-cell-specific factors. Additionally, Phf6KO cells show significant down-regulation of genes involved in the development and function of normal B cells, show up-regulation of genes involved in T-cell signaling, and give rise to mixed-lineage lymphoma in vivo. Engagement of divergent transcriptional programs results in phenotypic plasticity that leads to altered disease presentation in vivo, tolerance of aberrant oncogenic signaling, and differential sensitivity to frontline and targeted therapies. These findings suggest that active maintenance of a precise chromatin landscape is essential for sustaining proper leukemia cell identity and that loss of a single factor (PHF6) can cause focal changes in chromatin accessibility and nucleosome positioning that render cells susceptible to lineage transition.


Asunto(s)
Cromatina/genética , Regulación Neoplásica de la Expresión Génica , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Leucemia de Células B/genética , Leucemia de Células B/fisiopatología , Animales , Línea Celular Tumoral , Linaje de la Célula/genética , Cromatina/metabolismo , Resistencia a Antineoplásicos/genética , Técnicas de Inactivación de Genes , Linfoma no Hodgkin/genética , Ratones , Ratones Endogámicos C57BL , Fenotipo , Proteínas Represoras , Transducción de Señal/genética
4.
Cell ; 138(1): 114-28, 2009 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-19596239

RESUMEN

We describe a broad mechanistic framework for the transcriptional induction of mammalian primary response genes by Toll-like receptors and other stimuli. One major class of primary response genes is characterized by CpG-island promoters, which facilitate promiscuous induction from constitutively active chromatin without a requirement for SWI/SNF nucleosome remodeling complexes. The low nucleosome occupancy at promoters in this class can be attributed to the assembly of CpG islands into unstable nucleosomes, which may lead to SWI/SNF independence. Another major class consists of non-CpG-island promoters that assemble into stable nucleosomes, resulting in SWI/SNF dependence and a requirement for transcription factors that promote selective nucleosome remodeling. Some stimuli, including serum and tumor necrosis factor-alpha, exhibit a strong bias toward activation of SWI/SNF-independent CpG-island genes. In contrast, interferon-beta is strongly biased toward SWI/SNF-dependent non-CpG-island genes. By activating a diverse set of transcription factors, Toll-like receptors induce both classes and others for an optimal response to microbial pathogens.


Asunto(s)
Ensamble y Desensamble de Cromatina , Islas de CpG , Activación Transcripcional , Animales , Linfocitos T CD4-Positivos/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Humanos , Factor 3 Regulador del Interferón/metabolismo , Lipopolisacáridos/inmunología , Ratones , Nucleosomas/metabolismo , Regiones Promotoras Genéticas , Factores de Transcripción/metabolismo , Transcripción Genética
5.
PLoS Genet ; 17(11): e1009854, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34723967

RESUMEN

The forkhead box (Fox) family of transcription factors are highly conserved and play essential roles in a wide range of cellular and developmental processes. We report an individual with severe neurological symptoms including postnatal microcephaly, progressive brain atrophy and global developmental delay associated with a de novo missense variant (M280L) in the FOXR1 gene. At the protein level, M280L impaired FOXR1 expression and induced a nuclear aggregate phenotype due to protein misfolding and proteolysis. RNAseq and pathway analysis showed that FOXR1 acts as a transcriptional activator and repressor with central roles in heat shock response, chaperone cofactor-dependent protein refolding and cellular response to stress pathways. Indeed, FOXR1 expression is increased in response to cellular stress, a process in which it directly controls HSPA6, HSPA1A and DHRS2 transcripts. The M280L mutant compromises FOXR1's ability to respond to stress, in part due to impaired regulation of downstream target genes that are involved in the stress response pathway. Quantitative PCR of mouse embryo tissues show Foxr1 expression in the embryonic brain. Using CRISPR/Cas9 gene editing, we found that deletion of mouse Foxr1 leads to a severe survival deficit while surviving newborn Foxr1 knockout mice have reduced body weight. Further examination of newborn Foxr1 knockout brains revealed a decrease in cortical thickness and enlarged ventricles compared to littermate wild-type mice, suggesting that loss of Foxr1 leads to atypical brain development. Combined, these results suggest FOXR1 plays a role in cellular stress response pathways and is necessary for normal brain development.


Asunto(s)
Encéfalo/crecimiento & desarrollo , Factores de Transcripción Forkhead/fisiología , Estrés Fisiológico , Animales , Femenino , Factores de Transcripción Forkhead/genética , Células HEK293 , Humanos , Masculino , Ratones , Ratones Noqueados , Mutación Missense , Fenotipo
6.
Am J Physiol Endocrinol Metab ; 323(2): E123-E132, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-35723225

RESUMEN

Fibroblast growth factor 21 (FGF21) is increased acutely by carbohydrate ingestion and is elevated in patients with type 2 diabetes (T2D). However, the physiological significance of increased FGF21 in humans remains largely unknown. We examined whether FGF21 contributed to the metabolic improvements observed following treatment of patients with T2D with either triple (metformin/pioglitazone/exenatide) or conventional (metformin/insulin/glipizide) therapy for 3 yr. Forty-six patients with T2D were randomized to receive either triple or conventional therapy to maintain HbA1c < 6.5%. A 2-h 75-g oral glucose tolerance test (OGTT) was performed at baseline and following 3 years of treatment to assess glucose tolerance, insulin sensitivity, and ß-cell function. Plasma total and bioactive FGF21 levels were quantitated before and during the OGTT at both visits. Patients in both treatment arms experienced significant improvements in glucose control, but insulin sensitivity and ß-cell function were markedly increased after triple therapy. At baseline, FGF21 levels were regulated acutely during the OGTT in both groups. After treatment, fasting total and bioactive FGF21 levels were significantly reduced in patients receiving triple therapy, but there was a relative increase in the proportion of bioactive FGF21 compared with that observed in conventionally treated subjects. Relative to baseline studies, triple therapy treatment also significantly modified FGF21 levels in response to a glucose load. These changes in circulating FGF21 were correlated with markers of improved glucose control and insulin sensitivity. Alterations in the plasma FGF21 profile may contribute to the beneficial metabolic effects of pioglitazone and exenatide in human patients with T2D.NEW & NOTEWORTHY In patients with T2D treated with a combination of metformin/pioglitazone/exenatide (triple therapy), we observed reduced total and bioactive plasma FGF21 levels and a relative increase in the proportion of circulating bioactive FGF21 compared with that in patients treated with metformin and sequential addition of glipizide and basal insulin glargine (conventional therapy). These data suggest that FGF21 may contribute, at least in part, to the glycemic benefits observed following combination therapy in patients with T2D.


Asunto(s)
Diabetes Mellitus Tipo 2 , Resistencia a la Insulina , Metformina , Tiazolidinedionas , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Exenatida , Factores de Crecimiento de Fibroblastos , Glipizida , Hemoglobina Glucada/metabolismo , Humanos , Hipoglucemiantes/uso terapéutico , Metformina/uso terapéutico , Péptidos , Pioglitazona , Ponzoñas
7.
Ann Pharmacother ; 55(10): 1185-1194, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-33384014

RESUMEN

BACKGROUND: The US Food and Drug Administration (FDA) recommends using only FDA-reviewed pharmacogenetic information to make prescribing decisions based on genetic test results. Such information is available in drug labeling and in the Table of Pharmacogenetic Associations ("Associations table"). OBJECTIVE: To compile a list of drug-gene pairs from drug labeling and the Associations table and categorize the pharmacogenetic information and clinical outcome associated with each drug-gene pair. METHODS: This was a cross-sectional analysis of pharmacogenetic information in the Associations table and individual drug labeling in March 2020. We used the Table of Pharmacogenomic Biomarkers in Drug Labeling to identify drug labels to review. We categorized the pharmacogenetic information for each drug-gene pair according to whether the purpose was to describe (1) polymorphisms affecting drug disposition (metabolism or transport), (2) polymorphisms affecting a direct drug target, (3) variants associated with adverse drug reaction (ADR) susceptibility, (4) variants associated with therapeutic failure, (5) a biomarker-defined indication, or (6) a biomarker-defined ADR. We also categorized the clinical outcome-efficacy, safety, or unknown-associated with each drug-gene pair. We reported counts and proportions of drug-gene pairs in each pharmacogenetic information and clinical outcome category. RESULTS: We identified 308 drug-gene pairs, of which 36% were associated with a biomarker-defined drug indication, 33% with polymorphic drug metabolism, and 28% with ADR susceptibility. Most drug-gene pairs (n = 267, 87%) were associated with an efficacy or safety-related outcome. CONCLUSION AND RELEVANCE: FDA-reviewed pharmacogenetic information is available for more than 300 drug-gene pairs and can help guide prescribing decisions.


Asunto(s)
Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Farmacogenética , Estudios Transversales , Etiquetado de Medicamentos , Humanos , Estados Unidos , United States Food and Drug Administration
8.
Int J Obes (Lond) ; 44(2): 544-547, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31455871

RESUMEN

Fibroblast growth factor 21 (FGF21) is an important regulator of energy metabolism. FGF21 is inactivated by fibroblast activation protein (FAP). We investigated whether FGF21 and/or FAP are secreted from human white adipose tissue of individuals with obesity by measuring total FGF21, active FGF21, and FAP concentrations in arterialized blood and venous blood draining the subcutaneous abdominal adipose tissue (scAT). Measurements were performed under fasting conditions and after a high fat meal before and after diet-induced weight loss in 16 adults with BMI 27-35 kg/m2. FGF21 was not released from scAT, neither before nor after weight loss in agreement with an undetectable gene expression of FGF21 in this tissue. Although scAT showed significant gene expression of FAP, no release of FAP from the tissue could be detected. The high fat meal increased postprandial circulating FGF21 but not FAP. Circulating levels of FAP but not FGF21 were significantly reduced after weight loss. On the other hand, FAP expression in scAT was increased. In conclusion, release from scAT does not appear to contribute to circulating concentrations of FGF21 and FAP and their responses to ingestion of a high fat meal or weight loss, respectively, in individuals with obesity.


Asunto(s)
Factores de Crecimiento de Fibroblastos/sangre , Gelatinasas/sangre , Proteínas de la Membrana/sangre , Obesidad , Serina Endopeptidasas/sangre , Grasa Subcutánea Abdominal/metabolismo , Adulto , Dieta Reductora , Endopeptidasas , Humanos , Obesidad/sangre , Obesidad/dietoterapia , Obesidad/metabolismo
9.
Mol Cell ; 47(5): 810-22, 2012 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-22940246

RESUMEN

Understanding the principles governing mammalian gene regulation has been hampered by the difficulty in measuring in vivo binding dynamics of large numbers of transcription factors (TF) to DNA. Here, we develop a high-throughput Chromatin ImmunoPrecipitation (HT-ChIP) method to systematically map protein-DNA interactions. HT-ChIP was applied to define the dynamics of DNA binding by 25 TFs and 4 chromatin marks at 4 time-points following pathogen stimulus of dendritic cells. Analyzing over 180,000 TF-DNA interactions we find that TFs vary substantially in their temporal binding landscapes. This data suggests a model for transcription regulation whereby TF networks are hierarchically organized into cell differentiation factors, factors that bind targets prior to stimulus to prime them for induction, and factors that regulate specific gene programs. Overlaying HT-ChIP data on gene-expression dynamics shows that many TF-DNA interactions are established prior to the stimuli, predominantly at immediate-early genes, and identified specific TF ensembles that coordinately regulate gene-induction.


Asunto(s)
Inmunoprecipitación de Cromatina/métodos , Células Dendríticas/metabolismo , Regulación de la Expresión Génica , Ensayos Analíticos de Alto Rendimiento , Animales , ADN/genética , ADN/metabolismo , Ratones , Factores de Transcripción/metabolismo
10.
Exp Physiol ; 103(6): 876-883, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29663541

RESUMEN

NEW FINDINGS: What is the central question of this study? The role of FGF21 as an exercise-induced myokine remains controversial. The aim of this study was to determine whether eccentric exercise would augment the release of FGF21 and/or its regulatory enzyme, fibroblast activation protein α (FAP), from skeletal muscle tissue into the systemic circulation of healthy human volunteers. What is the main finding and its importance? Eccentric exercise does not release total or bioactive FGF21 from human skeletal muscle. However, exercise releases its regulatory enzyme, FAP, from tissue(s) other than muscle, which might play a role in the inactivation of FGF21. ABSTRACT: The primary aim of the investigation was to determine whether eccentric exercise would augment the release of the myokine fibroblast growth factor 21 (FGF21) and/or its regulatory enzyme, fibroblast activation protein α (FAP), from skeletal muscle tissue into the systemic circulation of healthy human volunteers. Physically active young healthy male volunteers (age 25.0 ± 10.7 years; body mass index 23.1 ± 7.9 kg m-2 ) completed three sets of 25 repetitions (with 5 min rest in between) of single-leg maximal eccentric contractions using their non-dominant leg, whilst the dominant leg served as a control. Arterialized blood samples from a hand vein and deep venous blood samples from the common femoral vein of the exercised leg, along with blood flow of the superficial femoral artery using Doppler ultrasound, were obtained before and after each exercise bout and every 20 min during the 3 h recovery period. Muscle biopsy samples were taken at baseline, immediately and 3 and 48 h postexercise. The main findings showed that there was no significant increase in total or bioactive FGF21 secreted from skeletal muscle into the systemic circulation in response to exercise. Furthermore, skeletal muscle FGF21 protein content was unchanged in response to exercise. However, there was a significant increase in arterialized and venous FAP concentrations, with no apparent contribution to its release from the exercised leg. These findings raise the possibility that the elevated levels of FAP might play a role in the inactivation of FGF21 during exercise.


Asunto(s)
Ejercicio Físico/fisiología , Factores de Crecimiento de Fibroblastos/sangre , Gelatinasas/sangre , Proteínas de la Membrana/sangre , Serina Endopeptidasas/sangre , Adulto , Endopeptidasas , Humanos , Masculino , Proteínas Musculares/sangre , Músculo Esquelético/metabolismo , Flujo Sanguíneo Regional/fisiología , Descanso/fisiología
11.
Angew Chem Int Ed Engl ; 57(31): 9670-9674, 2018 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-29870587

RESUMEN

Toward nitrogen functionalization, reactive terminal transition metal nitrides with high d-electron counts are of interest. A series of terminal MoIV nitride complexes were prepared within the context of exploring nitride/carbonyl coupling to cyanate. Reduction affords the first MoII nitrido complex, an early metal nitride with four valence d-electrons. The binding mode of the para-terphenyl diphosphine ancillary ligand changes to stabilize an electronic configuration with a high electron count and a formal M-N bond order of three. Even with an intact Mo≡N bond, this low-valent nitrido complex proves to be highly reactive, readily undergoing N-atom transfer upon addition of CO, releasing cyanate anion.

12.
J Hand Surg Am ; 42(7): 574.e1-574.e6, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28465015

RESUMEN

PURPOSE: To determine whether the incidence of complications varies between among types of distal phalangeal fractures in a pediatric population. METHODS: We retrospectively reviewed the medical records and radiographs of patients seen in the pediatric hand surgery clinic from 2011 to 2012 with a diagnosis of distal phalanx fracture. Patients were identified by International Classification of Diseases-Ninth Revision code (816.02 or 816.12). We reviewed 206 charts and included them in the study. Demographic data, location of the fracture, specific diagnosis, mechanism of injury, outcomes, and complications were recorded. The treating physicians clinically identified the outcomes and complications. RESULTS: Average age of patients was 7.5 years. Fracture distribution was tuft (37%), mallet (18%), Salter-Harris I/II (13%), shaft (11%), base (11%), Seymour (6%), Salter-Harris III/IV (2%), and tip amputation (1%). Complications occurred in 31% of patients. The highest rates were for Salter-Harris IV (100%), Seymour (62%), and mallet fractures (49%). There was a statistically significant difference in complication rate by diagnosis. The most common complications were infection (22%), stiffness (15%), and nail deformity (13%). CONCLUSIONS: Complications of distal phalanx fractures in children are frequent. The incidence varies by fracture type, the highest of which are for Salter-Harris IV, Seymour, and mallet fractures. Special care needs to be taken to reduce the complication rates of these common fractures. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.


Asunto(s)
Traumatismos de los Dedos/complicaciones , Falanges de los Dedos de la Mano/lesiones , Fijación de Fractura/efectos adversos , Fracturas Óseas/complicaciones , Fracturas Óseas/cirugía , Complicaciones Posoperatorias/epidemiología , Adolescente , Niño , Preescolar , Femenino , Traumatismos de los Dedos/cirugía , Humanos , Lactante , Masculino , Estudios Retrospectivos
13.
Clin J Sport Med ; 26(6): 497-501, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27783573

RESUMEN

OBJECTIVE: Pediatric head injuries occur commonly and are being reported in increasing numbers. Balance testing is a key component in the evaluation of suspected concussion, and the balance error scoring system (BESS) is likely the most well-known and widely used measure. To date, normative BESS scores for adults have been reported but not for children. DESIGN: Normative data for BESS scores and modified BESS scores were created in a cohort of healthy children. Potential variables were analyzed as predictors of BESS performance. SETTING: Local elementary and junior high schools. PARTICIPANTS: A total of 373 healthy children between the ages of 5 and 14. INTERVENTIONS: The BESS was performed on all children. ASSESSMENT OF RISK FACTORS: Gender, body mass index percentile, previous concussions, athletic participation, age, and the parental opinion of child's balance ability were examined as factors associated with the BESS score. MAIN OUTCOME MEASURES: BESS scores. RESULTS: Normative data are reported, stratified by age groups of 5 to 7 years, 8 to 10 years, and 11 to 14 years of age, for both BESS and modified BESS. Median BESS scores are 23 for children aged 5 to 7, 18 for children aged 8 to 10, and 16 for children aged 11 to 14. Median modified BESS scores are 8 for children age 5 to 7, 5 for children age 8 to 10, and 4 for children age 11 to 14. Increasing age and positive parental opinion regarding their child's balance ability were independently correlated with decreasing BESS scores (P < 0.01). CONCLUSIONS: The normative data on BESS scores for healthy children reported here provide age-stratified reference values for suspected balance alterations.


Asunto(s)
Conmoción Encefálica/diagnóstico , Examen Físico/normas , Adolescente , Niño , Preescolar , Femenino , Humanos , Masculino , Examen Físico/métodos , Estudios Prospectivos , Valores de Referencia
14.
Breast Cancer Res ; 17: 59, 2015 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-25902869

RESUMEN

INTRODUCTION: Breast cancer, the most common cause of cancer-related deaths worldwide among women, is a molecularly and clinically heterogeneous disease. Extensive genetic and epigenetic profiling of breast tumors has recently revealed novel putative driver genes, including p21-activated kinase (PAK)1. PAK1 is a serine/threonine kinase downstream of small GTP-binding proteins, Rac1 and Cdc42, and is an integral component of growth factor signaling networks and cellular functions fundamental to tumorigenesis. METHODS: PAK1 dysregulation (copy number gain, mRNA and protein expression) was evaluated in two cohorts of breast cancer tissues (n=980 and 1,108). A novel small molecule inhibitor, FRAX1036, and RNA interference were used to examine PAK1 loss of function and combination with docetaxel in vitro. Mechanism of action for the therapeutic combination, both cellular and molecular, was assessed via time-lapse microscopy and immunoblotting. RESULTS: We demonstrate that focal genomic amplification and overexpression of PAK1 are associated with poor clinical outcome in the luminal subtype of breast cancer (P=1.29×10(-4) and P=0.015, respectively). Given the role for PAK1 in regulating cytoskeletal organization, we hypothesized that combination of PAK1 inhibition with taxane treatment could be combined to further interfere with microtubule dynamics and cell survival. Consistent with this, administration of docetaxel with either a novel small molecule inhibitor of group I PAKs, FRAX1036, or PAK1 small interfering RNA oligonucleotides dramatically altered signaling to cytoskeletal-associated proteins, such as stathmin, and induced microtubule disorganization and cellular apoptosis. Live-cell imaging revealed that the duration of mitotic arrest mediated by docetaxel was significantly reduced in the presence of FRAX1036, and this was associated with increased kinetics of apoptosis. CONCLUSIONS: Taken together, these findings further support PAK1 as a potential target in breast cancer and suggest combination with taxanes as a viable strategy to increase anti-tumor efficacy.


Asunto(s)
Apoptosis/efectos de los fármacos , Neoplasias de la Mama/metabolismo , Microtúbulos/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Moduladores de Tubulina/farmacología , Quinasas p21 Activadas/antagonistas & inhibidores , Apoptosis/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/patología , Puntos de Control del Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Variaciones en el Número de Copia de ADN , Docetaxel , Sinergismo Farmacológico , Femenino , Amplificación de Genes , Expresión Génica , Humanos , Pronóstico , Transducción de Señal/efectos de los fármacos , Taxoides/farmacología , Quinasas p21 Activadas/genética , Quinasas p21 Activadas/metabolismo
15.
Proc Natl Acad Sci U S A ; 109(31): 12722-7, 2012 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-22802621

RESUMEN

Malignant glioma, the most common primary brain tumor, is generally incurable. Although phosphatidylinositol-3-kinase (PI3K) signaling features prominently in glioma, inhibitors generally block proliferation rather than induce apoptosis. Starting with an inhibitor of both lipid and protein kinases that induced prominent apoptosis and that failed early clinical development because of its broad target profile and overall toxicity, we identified protein kinase targets, the blockade of which showed selective synthetic lethality when combined with PI3K inhibitors. Prioritizing protein kinase targets for which there are clinical inhibitors, we demonstrate that cyclin-dependent kinase (CDK)1/2 inhibitors, siRNAs against CDK1/2, and the clinical CDK1/2 inhibitor roscovitine all cooperated with the PI3K inhibitor PIK-90, blocking the antiapoptotic protein Survivin and driving cell death. In addition, overexpression of CDKs partially blocked some of the apoptosis caused by PIK-75. Roscovitine and PIK-90, in combination, were well tolerated in vivo and acted in a synthetic-lethal manner to induce apoptosis in human glioblastoma xenografts. We also tested clinical Akt and CDK inhibitors, demonstrating induction of apoptosis in vitro and providing a preclinical rationale to test this combination therapy in patients.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Proteína Quinasa CDC2/antagonistas & inhibidores , Quinasa 2 Dependiente de la Ciclina/antagonistas & inhibidores , Glioma/tratamiento farmacológico , Proteínas de Neoplasias/antagonistas & inhibidores , Inhibidores de las Quinasa Fosfoinosítidos-3 , Inhibidores de Proteínas Quinasas/farmacología , Purinas/farmacología , Animales , Apoptosis/efectos de los fármacos , Proteína Quinasa CDC2/metabolismo , Línea Celular Tumoral , Quinasa 2 Dependiente de la Ciclina/metabolismo , Femenino , Glioma/enzimología , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Proteínas de Neoplasias/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Roscovitina , Ensayos Antitumor por Modelo de Xenoinjerto
16.
Carcinogenesis ; 35(11): 2485-94, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25115442

RESUMEN

Granulin-epithelin precursor (GEP) is a pluripotent secretory growth factor which promotes cancer progression in a number of human cancers. However, how cancer cells interact with GEP remains unknown. In this study, we aimed to identify the cell surface-binding partner of GEP on liver cancer cells. Human recombinant GEP (rGEP) was expressed and purified to homogeneity. The rGEP was shown to trigger phosphorylation of AKT and ERK1/2 in liver cancer cells. We demonstrated cell surface attachment of rGEP, which was blocked by prebinding of platelet-derived growth factor-AA, platelet-derived growth factor-BB and fibroblast growth factor-2. Therefore, heparan sulfate (HS) had been reasoned as the binding partner of rGEP. Heparinase digestion validated the role of HS on supporting the attachment. The heparin-binding domain of GEP was mapped to RRH(555-557) in the C-terminal region. Suppression of the HS polymerase exostosin-1 reduced the rGEP binding and rGEP-mediated signaling transduction. Suppression of a specific HS proteoglycan, glypican-3, also showed a partial reduction of rGEP binding and an inhibition on rGEP-mediated activation of AKT. Furthermore, glypican-3 was shown to correlate with the expressions of GEP in clinical samples (Spearman's ρ = 0.363, P = 0.001). This study identified HS, partly through glypican-3, as a novel binding partner of GEP on the surface of liver cancer cells.


Asunto(s)
Carcinoma Hepatocelular/genética , Glipicanos/metabolismo , Heparitina Sulfato/metabolismo , Péptidos y Proteínas de Señalización Intercelular/genética , Neoplasias Hepáticas/genética , Carcinoma Hepatocelular/patología , Factor 2 de Crecimiento de Fibroblastos/biosíntesis , Factor 2 de Crecimiento de Fibroblastos/genética , Regulación Neoplásica de la Expresión Génica , Glipicanos/antagonistas & inhibidores , Células Hep G2 , Heparitina Sulfato/genética , Humanos , Péptidos y Proteínas de Señalización Intercelular/biosíntesis , Neoplasias Hepáticas/metabolismo , Sistema de Señalización de MAP Quinasas/genética , Proteína Oncogénica v-akt/genética , Progranulinas , Unión Proteica
17.
J Am Chem Soc ; 136(32): 11272-5, 2014 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-25034459

RESUMEN

Though numerous catalysts for the dehydrogenation of ammonia borane (AB) are known, those that release >2 equiv of H2 are uncommon. Herein, we report the synthesis of Mo complexes supported by a para-terphenyl diphosphine ligand, 1, displaying metal-arene interactions. Both a Mo(0) N2 complex, 5, and a Mo(II) bis(acetonitrile) complex, 4, exhibit high levels of AB dehydrogenation, releasing over 2.0 equiv of H2. The reaction rate, extent of dehydrogenation, and reaction mechanism vary as a function of the precatalyst oxidation state. Several Mo hydrides (Mo(II)(H)2, [Mo(II)(H)](+), and [Mo(IV)(H)3](+)) relevant to AB chemistry were characterized.

18.
Toxicol Appl Pharmacol ; 278(1): 65-71, 2014 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-24769090

RESUMEN

The toxic effects of dioxins, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), mainly through activation of the aryl hydrocarbon receptor (AhR) are well documented. Fibroblast growth factor (Fgf) 21 plays critical roles in metabolic adaptation to fasting by increasing lipid oxidation and ketogenesis in the liver. The present study was performed to determine whether activation of the AhR induces Fgf21 expression. In mouse liver, TCDD increased Fgf21 mRNA in both dose- and time-dependent manners. In addition, TCDD markedly increased Fgf21 mRNA expression in cultured mouse and human hepatocytes. Moreover, TCDD increased mRNA (in liver) and protein levels (in both liver and serum) of Fgf21 in wild-type mice, but not in AhR-null mice. Chromatin immunoprecipitation assays showed that TCDD increased AhR protein binding to the Fgf21 promoter (-105/+1 base pair). Fgf21-null mice administered 200µg/kg of TCDD died within 20days, whereas wild-type mice receiving the same treatment were still alive at one month after administration. This indicates that TCDD-induced Fgf21 expression protects against TCDD toxicity. Diethylhexylphthalate (DEHP) pretreatment attenuated TCDD-induced Fgf21 expression in mouse liver and white adipose tissue, which may explain a previous report that DEHP pretreatment decreases TCDD-induced wasting. In conclusion, Fgf21 appears to be a target gene of AhR-signaling pathway in mouse and human liver.


Asunto(s)
Tejido Adiposo Blanco/efectos de los fármacos , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Crecimiento de Fibroblastos/metabolismo , Hígado/efectos de los fármacos , Receptores de Hidrocarburo de Aril/metabolismo , Tejido Adiposo Blanco/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/agonistas , Sitios de Unión , Línea Celular , Dietilhexil Ftalato/farmacología , Relación Dosis-Respuesta a Droga , Factores de Crecimiento de Fibroblastos/deficiencia , Factores de Crecimiento de Fibroblastos/genética , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Humanos , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Dibenzodioxinas Policloradas/toxicidad , Regiones Promotoras Genéticas , ARN Mensajero/metabolismo , Receptores de Hidrocarburo de Aril/agonistas , Transducción de Señal/efectos de los fármacos , Factores de Tiempo , Regulación hacia Arriba
19.
Am J Public Health ; 104(5): 796-802, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24625143

RESUMEN

Smoking is a major contributor to premature mortality among people with mental illness and substance abuse. Historically, the Substance Abuse and Mental Health Services Administration (SAMHSA) did not include smoking cessation in its mission. We describe the development of a unique partnership between SAMHSA and the University of California, San Francisco's Smoking Cessation Leadership Center. Starting with an educational summit in Virginia in 2007, it progressed to a jointly sponsored "100 Pioneers for Smoking Cessation" campaign that provided grants and technical assistance to organizations promoting cessation. By 2013, the partnership established 7 "Leadership Academies," state-level multidisciplinary collaboratives of organizations focused on cessation. This academic-public partnership increased tobacco quit attempts, improved collaboration across multiple agencies, and raised awareness about tobacco use in vulnerable populations.


Asunto(s)
Relaciones Interinstitucionales , Cese del Hábito de Fumar , United States Substance Abuse and Mental Health Services Administration/organización & administración , Universidades/organización & administración , Conducta Cooperativa , Educación en Salud , Política de Salud , Humanos , Liderazgo , Contaminación por Humo de Tabaco/legislación & jurisprudencia , Estados Unidos
20.
PLoS Genet ; 7(12): e1002401, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22174696

RESUMEN

Precise control of the innate immune response is required for resistance to microbial infections and maintenance of normal tissue homeostasis. Because this response involves coordinate regulation of hundreds of genes, it provides a powerful biological system to elucidate the molecular strategies that underlie signal- and time-dependent transitions of gene expression. Comprehensive genome-wide analysis of the epigenetic and transcription status of the TLR4-induced transcriptional program in macrophages suggests that Toll-like receptor 4 (TLR4)-dependent activation of nearly all immediate/early- (I/E) and late-response genes results from a sequential process in which signal-independent factors initially establish basal levels of gene expression that are then amplified by signal-dependent transcription factors. Promoters of I/E genes are distinguished from those of late genes by encoding a distinct set of signal-dependent transcription factor elements, including TATA boxes, which lead to preferential binding of TBP and basal enrichment for RNA polymerase II immediately downstream of transcriptional start sites. Global nuclear run-on (GRO) sequencing and total RNA sequencing further indicates that TLR4 signaling markedly increases the overall rates of both transcriptional initiation and the efficiency of transcriptional elongation of nearly all I/E genes, while RNA splicing is largely unaffected. Collectively, these findings reveal broadly utilized mechanisms underlying temporally distinct patterns of TLR4-dependent gene activation required for homeostasis and effective immune responses.


Asunto(s)
N-Metiltransferasa de Histona-Lisina/genética , Inmunidad Innata/genética , Inflamación/genética , Macrófagos/metabolismo , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/metabolismo , Animales , Células Cultivadas , Epigénesis Genética/genética , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Células Madre Hematopoyéticas , N-Metiltransferasa de Histona-Lisina/metabolismo , Histonas/genética , Histonas/metabolismo , Homeostasis , Humanos , Inmunidad Innata/inmunología , Inflamación/inmunología , Ratones , Regiones Promotoras Genéticas/genética , ARN Polimerasa II/genética , ARN Polimerasa II/metabolismo , Transducción de Señal , TATA Box/genética , Factores de Transcripción , Activación Transcripcional/genética , Activación Transcripcional/inmunología
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