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1.
Am J Pathol ; 189(3): 482-491, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30414411

RESUMEN

The transcription factor Nur77 belongs to the NR4A subfamily of nuclear hormone receptors. It features an atypical ligand-binding site that precludes canonical ligand binding, leading to the designation orphan nuclear receptor. However, recent studies show that small molecules can interact with the receptor and modulate its activity by inducing a conformational change in the Nur77 ligand-binding site. Nur77 expression and activation are rapidly induced by various physiological and pathologic stimuli. Once expressed, Nur77 initiates transcriptional activity and modulates expression of its target genes. Both in vitro and in vivo evidence shows that Nur77 dampens the immune response to proinflammatory stimuli, such as tumor necrosis factor-α, Toll-like receptor ligands, and oxidized lipids, primarily by suppressing NF-κB signaling. Although studies focusing on Nur77's role in lung pathophysiology are currently incomplete, available data support its involvement in the pathogenesis of lung diseases, including asthma, acute lung injury, and pulmonary fibrosis, and thus suggest a therapeutic potential for Nur77 activation in these diseases. This review addresses the mechanisms that control Nur77 as well as its known roles in inflammation-related lung diseases. Evidence regarding the therapeutic potential of Nur77-targeting molecules will also be presented. Although current knowledge is limited, additional research followed by clinical studies may firmly identify Nur77 as a pharmacologic target for inflammation-related lung diseases.


Asunto(s)
Enfermedades Pulmonares/metabolismo , Pulmón/metabolismo , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Transducción de Señal , Transcripción Genética , Animales , Humanos , Inflamación/metabolismo , Inflamación/patología , Pulmón/patología , Enfermedades Pulmonares/patología , Enfermedades Pulmonares/terapia , FN-kappa B/biosíntesis , Receptores Toll-Like/biosíntesis , Factor de Necrosis Tumoral alfa/biosíntesis
2.
Clin Sci (Lond) ; 134(9): 1063-1079, 2020 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-32369100

RESUMEN

Asthma is a chronic disease of the airways that has long been viewed predominately as an inflammatory condition. Accordingly, current therapeutic interventions focus primarily on resolving inflammation. However, the mainstay of asthma therapy neither fully improves lung function nor prevents disease exacerbations, suggesting involvement of other factors. An emerging concept now holds that airway remodeling, another major pathological feature of asthma, is as important as inflammation in asthma pathogenesis. Structural changes associated with asthma include disrupted epithelial integrity, subepithelial fibrosis, goblet cell hyperplasia/metaplasia, smooth muscle hypertrophy/hyperplasia, and enhanced vascularity. These alterations are hypothesized to contribute to airway hyperresponsiveness, airway obstruction, airflow limitation, and progressive decline of lung function in asthmatic individuals. Consequently, targeting inflammation alone does not suffice to provide optimal clinical benefits. Here we review asthmatic airway remodeling, focusing on airway epithelium, which is critical to maintaining a healthy respiratory system, and is the primary defense against inhaled irritants. In asthma, airway epithelium is both a mediator and target of inflammation, manifesting remodeling and resulting obstruction among its downstream effects. We also highlight the potential benefits of therapeutically targeting airway structural alterations. Since pathological tissue remodeling is likewise observed in other injury- and inflammation-prone tissues and organs, our discussion may have implications beyond asthma and lung disease.


Asunto(s)
Remodelación de las Vías Aéreas (Respiratorias)/efectos de los fármacos , Antiasmáticos/farmacología , Asma/fisiopatología , Inflamación/tratamiento farmacológico , Animales , Asma/tratamiento farmacológico , Epitelio/efectos de los fármacos , Humanos , Inflamación/fisiopatología , Pulmón/efectos de los fármacos , Pulmón/fisiopatología
3.
J Immunol ; 201(6): 1775-1783, 2018 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-30061200

RESUMEN

Airway epithelial cells (AECs) orchestrate inflammatory responses to airborne irritants that enter the respiratory system. A viscous mucus layer produced by goblet cells in the airway epithelium also contributes to a physiological defense mechanism through the physical and chemical barriers it provides. Dysregulation or impairment in these functions has been implicated as a cause of the chronic inflammation and tissue remodeling that constitute major pathological features of asthma. In particular, mucus hypersecretion leading to airway obstruction and impaired pulmonary function is associated with morbidity and mortality in asthma patients. Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor involved in a variety of cellular processes. Accumulating evidence indicates that PPARγ agonists antagonize exaggerated inflammatory responses, yet PPARγ's precise role in airway remodeling/mucus hypersecretion has yet to be defined. In this study, we created an AEC-specific PPARγ (AEC-PPARγ) deletion to investigate PPARγ's functions in a murine model of allergic airway disease. AEC-PPARγ deficiency exaggerated airway hyperresponsiveness, inflammation, cytokine expression, and tissue remodeling. We also found that PPARγ directly bound to a PPAR response element found in MUC5AC and repressed gene expression. Likewise, PPARγ regulated mucin and inflammatory factors in primary human bronchial epithelial cells. In light of the current standard therapies' limited and inadequate direct effect on airway mucus hypersecretion, our study showing AEC-PPARγ's role as a transcriptional repressor of MUC5AC highlights this receptor's potential as a pharmacological target for asthma.


Asunto(s)
Asma/inmunología , Células Epiteliales/inmunología , Regulación de la Expresión Génica/inmunología , Mucina 5AC/inmunología , PPAR gamma/inmunología , Mucosa Respiratoria/inmunología , Animales , Asma/genética , Asma/patología , Células Cultivadas , Células Epiteliales/patología , Femenino , Humanos , Inflamación/genética , Inflamación/inmunología , Inflamación/patología , Masculino , Ratones , Ratones Noqueados , Mucina 5AC/genética , PPAR gamma/genética , Mucosa Respiratoria/patología , Elementos de Respuesta/inmunología
4.
Biochem J ; 476(19): 2757-2767, 2019 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-31492735

RESUMEN

Nur77 is a transcription factor belonging to the NR4A subfamily of nuclear hormone receptors. Upon induction, Nur77 modulates the expression of its target genes and controls a variety of biological and pathophysiological processes. Prior research that revealed a structurally atypical ligand-binding domain (LBD) and failed to locate an endogenous ligand had led to a classification of Nur77 as an orphan receptor. However, several more recent studies indicate that small synthetic molecules and unsaturated fatty acids can bind to Nur77. Discovery of additional endogenous ligands will facilitate our understanding of the receptor's functions and regulatory mechanisms. Our data have identified prostaglandin A2 (PGA2), a cyclopentenone prostaglandin (PG), as such a ligand. Cyclopentenone PGs exert their biological effects primarily by forming protein adducts via the characteristic electrophilic ß-carbon(s) located in their cyclopentenone rings. Our data show that PGA2 induces Nur77 transcriptional activity by forming a covalent adduct between its endocyclic ß-carbon, C9, and Cys566 in the receptor's LBD. The importance of this endocyclic ß-carbon was substantiated by the failure of PGs without such electrophilic properties to react with Nur77. Calculated chemical properties and data from reactive molecular dynamic simulations, intrinsic reaction co-ordinate modeling, and covalent molecular docking also corroborate the selectivity of PGA2's C9 ß-carbon towards Nur77's Cys. In summary, our molecular, chemical, and structural characterization of the PGA2-Nur77 interaction provides the first evidence that PGA2 is an endogenous Nur77 agonist.


Asunto(s)
Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/agonistas , Prostaglandinas A/química , Prostaglandinas A/fisiología , Línea Celular , Humanos , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Prostaglandinas A/metabolismo , Unión Proteica , Dominios Proteicos
5.
J Immunol ; 194(6): 2551-60, 2015 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-25667416

RESUMEN

The link between autoimmune diseases and primary immunodeficiency syndromes has been increasingly appreciated. Immunologic evaluation of a young man with autoimmune enterocolopathy and unexplained infections revealed evidence of immunodeficiency, including IgG subclass deficiency, impaired Ag-induced lymphocyte proliferation, reduced cytokine production by CD8(+) T lymphocytes, and decreased numbers of NK cells. Genetic evaluation identified haploinsufficiency of NFAT5, a transcription factor regulating immune cell function and cellular adaptation to hyperosmotic stress, as a possible cause of this syndrome. Inhibition or deletion of NFAT5 in normal human and murine cells recapitulated several of the immune deficits identified in the patient. These results provide evidence of a primary immunodeficiency disorder associated with organ-specific autoimmunity linked to NFAT5 deficiency.


Asunto(s)
Enfermedades Autoinmunes/inmunología , Enfermedades Gastrointestinales/inmunología , Haploinsuficiencia/inmunología , Síndromes de Inmunodeficiencia/inmunología , Factores de Transcripción/inmunología , Animales , Enfermedades Autoinmunes/diagnóstico , Enfermedades Autoinmunes/genética , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Células Cultivadas , Citocinas/inmunología , Citocinas/metabolismo , Análisis Mutacional de ADN , Enfermedades Gastrointestinales/diagnóstico , Enfermedades Gastrointestinales/genética , Expresión Génica/inmunología , Haploinsuficiencia/genética , Humanos , Immunoblotting , Síndromes de Inmunodeficiencia/diagnóstico , Síndromes de Inmunodeficiencia/genética , Células Jurkat , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Masculino , Ratones de la Cepa 129 , Ratones Noqueados , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Adulto Joven
6.
J Biol Chem ; 287(17): 13799-812, 2012 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-22351767

RESUMEN

Talin, which is composed of head (THD) and rod domains, plays an important role in cell adhesion events in diverse species including most metazoans and Dictyostelium discoideum. Talin is abundant in the cytosol; however, it mediates adhesion by associating with integrins in the plasma membrane where it forms a primary link between integrins and the actin cytoskeleton. Cells modulate the partitioning of talin between the plasma membrane and the cytosol to control cell adhesion. Here, we combine nuclear magnetic resonance spectroscopy (NMR) with subcellular fractionation to characterize two distinct THD-rod domain interactions that control the interaction of talin with the actin cytoskeleton or its localization to the plasma membrane. An interaction between a discrete vinculin-binding region of the rod (VBS1/2a; Tln1(482-787)), and the THD restrains talin from interacting with the plasma membrane. Furthermore, we show that vinculin binding to VBS1/2a results in talin recruitment to the plasma membrane. Thus, we have structurally defined specific inter-domain interactions between THD and the talin rod domain that regulate the subcellular localization of talin.


Asunto(s)
Regulación de la Expresión Génica , Talina/biosíntesis , Actinas/metabolismo , Animales , Células CHO , Membrana Celular/metabolismo , Cricetinae , Cricetulus , Citoesqueleto/metabolismo , Citosol/metabolismo , Humanos , Espectroscopía de Resonancia Magnética/métodos , Modelos Moleculares , Conformación Proteica , Estructura Terciaria de Proteína , Fracciones Subcelulares/metabolismo , Talina/química
7.
Proc Natl Acad Sci U S A ; 105(46): 17967-72, 2008 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-19004799

RESUMEN

During blast crisis of chronic myelogenous leukemia (CML), abnormal granulocyte macrophage progenitors (GMP) with nuclear beta-catenin acquire self-renewal potential and may function as leukemic stem cells (Jamieson et al. N Engl J Med, 2004). To develop a mouse model for CML-initiating GMP, we expressed p210(BCR-ABL) in an established line of E2A-knockout mouse BM cells that retain pluripotency in ex vivo culture. Expression of BCR-ABL in these cells reproducibly stimulated myeloid expansion in culture and generated leukemia-initiating cells specifically in the GMP compartment. The leukemogenic GMP displayed higher levels of beta-catenin activity than either the nontransformed GMP or the transformed nonGMP, both in culture and in transplanted mouse BM. Although E2A-deficiency may have contributed to the formation of leukemogenic GMP, restoration of E2A-function did not reverse BCR-ABL-induced transformation. These results provide further evidence that BCR-ABL-transformed GMP with abnormal beta-catenin activity can function as leukemic stem cells.


Asunto(s)
Transformación Celular Neoplásica/patología , Proteínas de Fusión bcr-abl/metabolismo , Células Progenitoras de Granulocitos y Macrófagos/patología , Células Progenitoras Mieloides/patología , Células Madre Neoplásicas/patología , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/deficiencia , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Células Cultivadas , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , beta Catenina/metabolismo
8.
Artículo en Inglés | MEDLINE | ID: mdl-32021151

RESUMEN

Background: Glucocorticoids are commonly prescribed to treat inflammation of the respiratory system; however, they are mostly ineffective for controlling chronic obstructive pulmonary disease (COPD)-associated inflammation. This study aimed to elucidate the molecular mechanisms responsible for such glucocorticoid inefficacy in COPD, which may be instrumental to providing better patient outcomes. Roflumilast is a selective phosphodiesterase-4 (PDE4) inhibitor with anti-inflammatory properties in severe COPD patients who have a history of exacerbations. Roflumilast has a suggested ability to mitigate glucocorticoid resistance, but the mechanism is unknown. Methods: To understand the mechanism that mediates roflumilast-induced restoration of glucocorticoid sensitivity in COPD, we tested the role of glucocorticoid receptor α (GRα). Roflumilast's effects on GRα expression and transcriptional activity were assessed in bronchial epithelial cells from COPD patients. Results: We found that both GRα expression and activity are downregulated in bronchial epithelial cells from COPD patients and that roflumilast stimulates both GRα mRNA synthesis and GRα's transcriptional activity in COPD bronchial epithelial cells. We also demonstrate that roflumilast enhances dexamethasone's ability to suppress pro-inflammatory mediator production, in a GRα-dependent manner. Discussion: Our findings highlight the significance of roflumilast-induced GRα upregulation for COPD therapeutic strategies by revealing that roflumilast restores glucocorticoid sensitivity by sustaining GRα expression.


Asunto(s)
Aminopiridinas/farmacología , Benzamidas/farmacología , Dexametasona/farmacología , Células Epiteliales/efectos de los fármacos , Glucocorticoides/farmacología , Pulmón/efectos de los fármacos , Inhibidores de Fosfodiesterasa 4/farmacología , Enfermedad Pulmonar Obstructiva Crónica/tratamiento farmacológico , Receptores de Glucocorticoides/agonistas , Células Cultivadas , Ciclopropanos/farmacología , Resistencia a Medicamentos , Células Epiteliales/metabolismo , Humanos , Mediadores de Inflamación/metabolismo , Interleucina-8/metabolismo , Pulmón/metabolismo , Pulmón/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/genética , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Receptores de Glucocorticoides/genética , Receptores de Glucocorticoides/metabolismo , Factor de Transcripción ReIA/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Regulación hacia Arriba
9.
PLoS One ; 15(2): e0229256, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32084204

RESUMEN

Cigarette smoke (CS) contains multiple gaseous and particulate materials that can cause lung inflammation, and smoking is the major cause of chronic obstructive pulmonary disease (COPD). We sought to determine the mechanisms of how CS triggers lung inflammation. Nur77, a nuclear hormone receptor belonging to the immediate-early response gene family, controls inflammatory responses, mainly by suppressing the NF-κB signaling pathway. Because it is unknown if Nur77's anti-inflammatory role modulates COPD, we assessed if and how Nur77 expression and activity are altered in CS-induced airway inflammation. In lung tissues and bronchial epithelial cells from COPD patients, we found Nur77 was downregulated. In a murine model of CS-induced airway inflammation, CS promoted lung inflammation and also reduced Nur77 activity in wild type (WT) mice, whereas lungs of Nur77-deficient mice showed exaggerated CS-induced inflammatory responses. Our findings in in vitro studies of human airway epithelial cells complemented those in vivo data in mice, together showing that CS induced threonine-phosphorylation of Nur77, which is known to interfere with its anti-inflammatory functions. In summary, our findings point to Nur77 as an important regulator of CS-induced inflammatory responses and support the potential benefits of Nur77 activation for COPD treatment.


Asunto(s)
Regulación hacia Abajo/efectos de los fármacos , Nicotiana/química , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Enfermedad Pulmonar Obstructiva Crónica/genética , Humo/efectos adversos , Animales , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Humanos , Inflamación/genética , Pulmón/patología , Ratones , Fosforilación/efectos de los fármacos , Enfermedad Pulmonar Obstructiva Crónica/patología , Treonina/metabolismo
10.
Mol Cell Biol ; 26(19): 7145-54, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16980617

RESUMEN

R-Ras3/M-Ras is a member of the RAS superfamily of small-molecular-weight GTP-binding proteins. Previous studies have demonstrated high levels of expression in several regions of the central nervous system, and a constitutively active form of M-Ras promotes cytoskeletal reorganization, cellular transformation, survival, and differentiation. However, the physiological functions of M-Ras during embryogenesis and postnatal development have not been elucidated. By using a specific M-Ras antibody, we demonstrated a high level of M-Ras expression in astrocytes, in addition to neurons. Endogenous M-Ras was activated by several trophic factors in astrocytes, including epidermal growth factor (EGF), basic fibroblast growth factor, and hepatocyte growth factor. Interestingly, M-Ras activation by EGF was more sustained compared to prototypic Ras. A mouse strain deficient in M-Ras was generated to investigate its role in development. M-Ras null mice appeared phenotypically normal, and there was a lack of detectable morphological and neurological defects. In addition, primary astrocytes derived from Mras(-/-) mice did not appear to display substantial alterations in the activation of both the mitogen-activated protein kinase and phosphatidylinositol 3-kinase pathways in response to trophic factors.


Asunto(s)
Sustancias de Crecimiento/farmacología , Proteínas de Unión al GTP Monoméricas/metabolismo , Transducción de Señal/efectos de los fármacos , Animales , Astrocitos/citología , Astrocitos/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Perfilación de la Expresión Génica , Regulación de la Expresión Génica/efectos de los fármacos , Hipocampo/citología , Hipocampo/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas de Unión al GTP Monoméricas/deficiencia , Proteínas de Unión al GTP Monoméricas/genética , Fosfotransferasas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reproducibilidad de los Resultados , Proteínas ras
11.
Artículo en Inglés | MEDLINE | ID: mdl-29450204

RESUMEN

Asthma affects approximately 300 million people worldwide, significantly impacting quality of life and healthcare costs. While current therapies are effective in controlling many patients' symptoms, a large number continue to experience exacerbations or treatment-related adverse effects. Alternative therapies are thus urgently needed. Accumulating evidence has shown that the peroxisome proliferator-activated receptor (PPAR) family of nuclear hormone receptors, comprising PPARα, PPARß/δ, and PPARγ, is involved in asthma pathogenesis and that ligand-induced activation of these receptors suppresses asthma pathology. PPAR agonists exert their anti-inflammatory effects primarily by suppressing pro-inflammatory mediators and antagonizing the pro-inflammatory functions of various cell types relevant to asthma pathophysiology. Experimental findings strongly support the potential clinical benefits of PPAR agonists in the treatment of asthma. We review current literature, highlighting PPARs' key role in asthma pathogenesis and their agonists' therapeutic potential. With additional research and rigorous clinical studies, PPARs may become attractive therapeutic targets in this disease.

12.
Free Radic Biol Med ; 126: 350-357, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30118830

RESUMEN

Cigarette smoke, a source of numerous oxidants, produces oxidative stress and exaggerated inflammatory responses that lead to irreversible lung tissue damage. It is the single, most significant risk factor for chronic obstructive pulmonary disease (COPD). Although an intrinsic defense system that includes both enzymatic and non-enzymatic modulators exists to protect lung tissues against oxidative stress, impairment of these protective mechanisms has been demonstrated in smokers and COPD patients. The antioxidant enzyme GSH peroxidase (GPx) is an important part of this intrinsic defense system. Although cigarette smoke has been shown to downregulate its expression and activity, the underlying mechanism is not known. Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear hormone receptor with antioxidant effects. PPARγ activation has demonstrated protective effects against cigarette smoke-induced oxidative stress and inflammation. Molecular mechanisms for PPARγ's antioxidant function likewise remain to be elucidated. This study explored the link between PPARγ and GPx3 and found a positive association in cigarette smoke extract (CSE)-exposed human bronchial epithelial cells. Moreover, we provide evidence that identifies GPx3 as a PPARγ transcriptional target. Attenuation of antioxidant effects in the absence of GPx3 highlights the antioxidant's prominent role in mediating PPARγ's function. We also demonstrate that ligand-mediated PPARγ activation blocks CSE-induced reactive oxygen species and hydrogen peroxide production via upregulation of GPx3. In summary, our findings describing the molecular mechanisms involving GPx3 and PPARγ in CSE-induced oxidative stress and inflammation may provide valuable information for the development of more effective therapeutics for COPD.


Asunto(s)
Fumar Cigarrillos/efectos adversos , Glutatión Peroxidasa/genética , PPAR gamma/genética , Enfermedad Pulmonar Obstructiva Crónica/genética , Antioxidantes/metabolismo , Bronquios/efectos de los fármacos , Bronquios/metabolismo , Línea Celular , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Glutatión Peroxidasa/metabolismo , Humanos , Estrés Oxidativo/genética , PPAR gamma/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/patología , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos , Fumar/efectos adversos
13.
ACS Chem Biol ; 13(12): 3269-3278, 2018 12 21.
Artículo en Inglés | MEDLINE | ID: mdl-30398845

RESUMEN

PPARδ belongs to the peroxisome proliferator-activated receptor (PPAR) family of nuclear receptors. Upon activation by an agonist, PPARδ controls a variety of physiological processes via regulation of its target genes. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) is a cyclopentenone prostaglandin that features an electrophilic, α,ß-unsaturated ketone (an enone) in the cyclopentenone ring. Many of 15d-PGJ2's biological effects result from covalent interaction between C9 and the thiol group of a catalytic cysteine (Cys) in target proteins. In this study, we investigated whether 15d-PGJ2 activates PPARδ by forming a covalent adduct. Our data show that 15d-PGJ2 activates PPARδ's transcriptional activity through formation of a covalent adduct between its endocyclic enone at C9 and Cys249 in the receptor's ligand-binding domain. As expected, no adduct formation was seen following a Cys-to-Ser mutation at residue 249 (C249S) of PPARδ or with a PGD2/PGJ2 analogue that lacks the electrophilic C9. Furthermore, the PPARδ C249S mutation weakened induction of the receptor's DNA binding activity by 15d-PGJ2, which highlights the biological significance of our findings. Calculated chemical properties as well as data from molecular orbital calculations, reactive molecular dynamics simulations, and intrinsic reaction coordinate modeling also supported the selectivity of 15d-PGJ2's C9 toward PPARδ's Cys thiol. In summary, our results provide the molecular, chemical, and structural basis of 15d-PGJ2-mediated PPARδ activation, designating 15d-PGJ2 as the first covalent PPARδ ligand to be identified.


Asunto(s)
PPAR delta/agonistas , PPAR delta/metabolismo , Prostaglandina D2/análogos & derivados , Alquilación , Línea Celular , Cisteína/química , Teoría Funcional de la Densidad , Humanos , Ligandos , Modelos Químicos , Simulación de Dinámica Molecular , Mutación , PPAR delta/química , PPAR delta/genética , Prostaglandina D2/química , Prostaglandina D2/metabolismo , Prostaglandina D2/farmacología , Unión Proteica , Dominios Proteicos
14.
Cancer Res ; 65(13): 5761-8, 2005 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-15994951

RESUMEN

Prostate cancer is a leading cause of cancer death in men. Risk prognostication, treatment stratification, and the development of rational therapeutic strategies lag because the molecular mechanisms underlying the initiation and progression from primary to metastatic disease are unknown. Multiple lines of evidence now suggest that KLF6 is a key prostate cancer tumor suppressor gene including loss and/or mutation in prostate cancer tumors and cell lines and decreased KLF6 expression levels in recurrent prostate cancer samples. Most recently, we identified a common KLF6 germ line single nucleotide polymorphism that is associated with an increased relative risk of prostate cancer and the increased production of three alternatively spliced, dominant-negative KLF6 isoforms. Here we show that although wild-type KLF6 (wtKLF6) acts as a classic tumor suppressor, the single nucleotide polymorphism-increased splice isoform, KLF6 SV1, displays a markedly opposite effect on cell proliferation, colony formation, and invasion. In addition, whereas wtKLF6 knockdown increases tumor growth in nude mice >2-fold, short interfering RNA-mediated KLF6 SV1 inhibition reduces growth by approximately 50% and decreases the expression of a number of growth- and angiogenesis-related proteins. Together, these findings begin to highlight a dynamic and functional antagonism between wtKLF6 and its splice variant KLF6 SV1 in tumor growth and dissemination.


Asunto(s)
Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/genética , Transactivadores/antagonistas & inhibidores , Transactivadores/genética , Empalme Alternativo , Animales , Procesos de Crecimiento Celular/genética , Movimiento Celular/genética , Células Madre de Carcinoma Embrionario , Femenino , Regulación Neoplásica de la Expresión Génica , Silenciador del Gen , Humanos , Factor 6 Similar a Kruppel , Factores de Transcripción de Tipo Kruppel , Masculino , Ratones , Ratones Endogámicos BALB C , Invasividad Neoplásica , Células Madre Neoplásicas/patología , Neovascularización Patológica/genética , Neovascularización Patológica/patología , Neoplasias de la Próstata/irrigación sanguínea , Isoformas de Proteínas , ARN Interferente Pequeño/genética , Transfección
15.
PPAR Res ; 2017: 8252796, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28316613

RESUMEN

Lung cancer is the most common and most fatal of all malignancies worldwide. Furthermore, with more than half of all lung cancer patients presenting with distant metastases at the time of initial diagnosis, the overall prognosis for the disease is poor. There is thus a desperate need for new prevention and treatment strategies. Recently, a family of nuclear hormone receptors, the peroxisome proliferator-activated receptors (PPARs), has attracted significant attention for its role in various malignancies including lung cancer. Three PPARs, PPARα, PPARß/δ, and PPARγ, display distinct biological activities and varied influences on lung cancer biology. PPARα activation generally inhibits tumorigenesis through its antiangiogenic and anti-inflammatory effects. Activated PPARγ is also antitumorigenic and antimetastatic, regulating several functions of cancer cells and controlling the tumor microenvironment. Unlike PPARα and PPARγ, whether PPARß/δ activation is anti- or protumorigenic or even inconsequential currently remains an open question that requires additional investigation. This review of current literature emphasizes the multifaceted effects of PPAR agonists in lung cancer and discusses how they may be applied as novel therapeutic strategies for the disease.

16.
Oncotarget ; 7(16): 21527-41, 2016 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-26930717

RESUMEN

The epithelial-mesenchymal transition (EMT) endows carcinoma cells with phenotypic plasticity that can facilitate the formation of cancer stem cells (CSCs) and contribute to the metastatic cascade. While there is substantial support for the role of EMT in driving cancer cell dissemination, less is known about the intracellular molecular mechanisms that govern formation of CSCs via EMT. Here we show that ß2 and ß5 proteasome subunit activity is downregulated during EMT in immortalized human mammary epithelial cells. Moreover, selective proteasome inhibition enabled mammary epithelial cells to acquire certain morphologic and functional characteristics reminiscent of cancer stem cells, including CD44 expression, self-renewal, and tumor formation. Transcriptomic analyses suggested that proteasome-inhibited cells share gene expression signatures with cells that have undergone EMT, in part, through modulation of the TGF-ß signaling pathway. These findings suggest that selective downregulation of proteasome activity in mammary epithelial cells can initiate the EMT program and acquisition of a cancer stem cell-like phenotype. As proteasome inhibitors become increasingly used in cancer treatment, our findings highlight a potential risk of these therapeutic strategies and suggest a possible mechanism by which carcinoma cells may escape from proteasome inhibitor-based therapy.


Asunto(s)
Regulación hacia Abajo , Transición Epitelial-Mesenquimal , Células Madre Neoplásicas/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Animales , Biocatálisis/efectos de los fármacos , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Carcinogénesis/genética , Carcinogénesis/metabolismo , Carcinogénesis/patología , Línea Celular , Línea Celular Transformada , Femenino , Perfilación de la Expresión Génica/métodos , Humanos , Estimación de Kaplan-Meier , Ratones Desnudos , Inhibidores de Proteasoma/farmacología , Trasplante Heterólogo
17.
Oncogene ; 23(29): 5077-83, 2004 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-15064720

RESUMEN

The Kruppel-like transcription factor KLF6 is a novel tumor-suppressor gene mutated in a significant fraction of human prostate cancer. It is localized to human chromosome 10p14-15, a region that displays frequent loss of heterozygosity in glioblastoma multiforme (GBM). Indeed, mutations of the KLF6 gene have recently been reported in this tumor type. In this study, we report that the expression of KLF6 is attenuated in human GBM when compared with primary astrocytes. Expression of KLF6 in GBM cells reverts their tumorigenicity both in vitro and in vivo, which is correlated with its transactivation of the p21/CIP1/WAF1 promoter. Additionally, KLF6 inhibits cellular transformation induced by several oncogenes (c-sis/PDGF-B, v-src, H-Ras, and EGFR) that are components of signaling cascades implicated in GBM. Our results provide the first evidence of functional tumor suppression by KFL6, and its loss may contribute to glial tumor progression.


Asunto(s)
Genes Supresores de Tumor , Glioblastoma/genética , Proteínas Proto-Oncogénicas , Transactivadores/genética , Factores de Transcripción/metabolismo , Animales , Astrocitos/metabolismo , Neoplasias Encefálicas , Línea Celular , Transformación Celular Neoplásica , Glioblastoma/patología , Glioblastoma/prevención & control , Humanos , Factor 6 Similar a Kruppel , Factores de Transcripción de Tipo Kruppel , Ratones , Ratones Desnudos , Mutación , Trasplante de Neoplasias , Ratas , Células Tumorales Cultivadas
18.
PLoS One ; 7(3): e34056, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22457811

RESUMEN

Talins and kindlins bind to the integrin ß3 cytoplasmic tail and both are required for effective activation of integrin αIIbß3 and resulting high-affinity ligand binding in platelets. However, binding of the talin head domain alone to ß3 is sufficient to activate purified integrin αIIbß3 in vitro. Since talin is localized to the cytoplasm of unstimulated platelets, its re-localization to the plasma membrane and to the integrin is required for activation. Here we explored the mechanism whereby kindlins function as integrin co-activators. To test whether kindlins regulate talin recruitment to plasma membranes and to αIIbß3, full-length talin and kindlin recruitment to ß3 was studied using a reconstructed CHO cell model system that recapitulates agonist-induced αIIbß3 activation. Over-expression of kindlin-2, the endogenous kindlin isoform in CHO cells, promoted PAR1-mediated and talin-dependent ligand binding. In contrast, shRNA knockdown of kindlin-2 inhibited ligand binding. However, depletion of kindlin-2 by shRNA did not affect talin recruitment to the plasma membrane, as assessed by sub-cellular fractionation, and neither over-expression of kindlins nor depletion of kindlin-2 affected talin interaction with αIIbß3 in living cells, as monitored by bimolecular fluorescence complementation. Furthermore, talin failed to promote kindlin-2 association with αIIbß3 in CHO cells. In addition, purified talin and kindlin-3, the kindlin isoform expressed in platelets, failed to promote each other's binding to the ß3 cytoplasmic tail in vitro. Thus, kindlins do not promote initial talin recruitment to αIIbß3, suggesting that they co-activate integrin through a mechanism independent of recruitment.


Asunto(s)
Integrina beta3/metabolismo , Proteínas de la Membrana/fisiología , Proteínas de Neoplasias/fisiología , Glicoproteína IIb de Membrana Plaquetaria/metabolismo , Animales , Células CHO , Cricetinae , Cricetulus , Humanos
19.
Biochem Soc Trans ; 36(Pt 2): 229-34, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18363565

RESUMEN

Agonist stimulation of integrin receptors, composed of transmembrane alpha and beta subunits, leads cells to regulate integrin affinity ('activation'), a process that controls cell adhesion and migration, and extracellular matrix assembly. A final step in integrin activation is the binding of talin to integrin beta cytoplasmic domains. We used forward, reverse and synthetic genetics to engineer and order integrin activation pathways of a prototypic integrin, platelet alphaIIbbeta3. PMA activated alphaIIbbeta3 only after expression of both PKCalpha (protein kinase Calpha) and talin at levels approximating those in platelets. Inhibition of Rap1 GTPase reduced alphaIIbbeta3 activation, whereas expression of constitutively active Rap1A(G12V) bypassed the requirement for PKCalpha. Overexpression of a Rap effector, RIAM (Rap1-GTP-interacting adaptor molecule), activated alphaIIbbeta3 and bypassed the requirement for PKCalpha and Rap1. In addition, shRNA (short hairpin RNA)-mediated knockdown of RIAM blocked talin interaction with and activation of integrin alphaIIbbeta3. Rap1 activation caused the formation of an 'activation complex' containing talin and RIAM that redistributed to the plasma membrane and activated alphaIIbbeta3. The central finding was that this Rap1-induced formation of an 'integrin activation complex' leads to the unmasking of the integrin-binding site on talin, resulting in integrin activation.


Asunto(s)
Modelos Biológicos , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Proteínas Adaptadoras Transductoras de Señales/antagonistas & inhibidores , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Humanos , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/agonistas , Proteína Quinasa C-alfa/metabolismo , Transducción de Señal/fisiología , Talina/metabolismo , Proteínas de Unión al GTP rap1/metabolismo
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