Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
1.
Cancer Res ; 66(6): 3006-14, 2006 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-16540649

RESUMEN

Lysophosphatidic acid (LPA) is both a potential marker and a therapeutic target for ovarian cancer. It is critical to identify the sources of elevated LPA levels in ascites and blood of patients with ovarian cancer. We show here that human peritoneal mesothelial cells constitutively produce LPA, which accounts for a significant portion of the chemotactic activity of the conditioned medium from peritoneal mesothelial cells to ovarian cancer cells. Both production of LPA by peritoneal mesothelial cells and the chemotactic activity in the conditioned medium can be blocked by HELSS [an inhibitor of the calcium-independent phospholipase A(2) (iPLA(2))] and AACOCF(3) [an inhibitor of both cytosolic PLA(2) (cPLA(2)) and iPLA(2)]. Moreover, cell-based enzymatic activity assays for PLA(2) indicate that peritoneal mesothelial cells have strong constitutive PLA(2) activity. Receptors for LPA, LPA(2), and LPA(3) are involved in the conditioned medium-induced chemotactic activity. Invasion of ovarian cancer cells into peritoneal mesothelial cells has also been analyzed and shown to require PLA(2), LPA receptors, and the mitogen-activated protein/extracellular signal-regulated kinase kinase/extracellular signal-regulated kinase signaling pathway. Thus, we show here, for the first time, that human peritoneal mesothelial cells constitutively produce bioactive lipid signaling molecules, such as LPA, via iPLA(2) and/or cPLA(2) activities. Conditioned medium from peritoneal mesothelial cells stimulate migration, adhesion, and invasion of ovarian cancer cells, and may play similar roles in vivo.


Asunto(s)
Epitelio/metabolismo , Lisofosfolípidos/biosíntesis , Neoplasias Ováricas/patología , Peritoneo/metabolismo , Ácidos Araquidónicos/farmacología , Adhesión Celular/fisiología , Línea Celular Tumoral , Movimiento Celular/fisiología , Colágeno Tipo I , Medios de Cultivo Condicionados , Citosol/enzimología , Epitelio/enzimología , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Femenino , Fosfolipasas A2 Grupo VI , Humanos , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , Lisofosfolípidos/fisiología , Naftalenos/farmacología , Neoplasias Ováricas/enzimología , Neoplasias Ováricas/metabolismo , Cavidad Peritoneal/patología , Peritoneo/enzimología , Inhibidores de Fosfodiesterasa/farmacología , Fosfolipasas A/antagonistas & inhibidores , Fosfolipasas A/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Pironas/farmacología
2.
FASEB J ; 19(7): 819-21, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15857892

RESUMEN

Angiogenesis is critical for many physiological and pathological processes. We show here that the lipid sphingosylphosphorylcholine (SPC) induces angiogenesis in vivo and GPR4 is required for the biological effects of SPC on endothelial cells (EC). In human umbilical vein EC, down-regulation of GPR4 specifically inhibits SPC-, but not sphingosine-1-phosphate-, or vascular endothelial growth factor (VEGF)-induced tube formation. Re-introduction of GPR4 fully restores the activity of SPC. In microvascular EC, GPR4 plays a pivotal role in cell survival, growth, migration, and tube formation through both SPC-dependent and -independent pathways. The biological effects resulting from SPC/GPR4 interactions involve the activation of both phosphatidylinositol-3 kinase and Akt. Moreover, the effects of SPC on EC require SPC induced trans-phosphorylation and activation of the VEGF receptor 2. These results identify SPC and its receptor, GPR4, as critical regulators of the angiogenic potential of EC.


Asunto(s)
Células Endoteliales/fisiología , Neovascularización Fisiológica/fisiología , Fosforilcolina/análogos & derivados , Receptores Acoplados a Proteínas G/fisiología , Esfingosina/análogos & derivados , Animales , Anticuerpos/farmacología , División Celular/fisiología , Movimiento Celular/fisiología , Supervivencia Celular/fisiología , Células Cultivadas , Embrión de Pollo , Activación Enzimática , Expresión Génica/efectos de los fármacos , Humanos , Concentración de Iones de Hidrógeno , Lisofosfolípidos/farmacología , Neovascularización Fisiológica/efectos de los fármacos , Proteína Oncogénica v-akt/metabolismo , Fragmentos de Péptidos/inmunología , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilcolina/farmacología , ARN Interferente Pequeño/farmacología , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/inmunología , Receptores de Factores de Crecimiento Endotelial Vascular/fisiología , Esfingosina/farmacología , Venas Umbilicales , Factor A de Crecimiento Endotelial Vascular/farmacología
3.
FASEB J ; 17(11): 1570-2, 2003 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12824286

RESUMEN

We have reported previously that levels of lysophosphatidic acid (LPA) are elevated in the blood and ascites from patients with ovarian cancer. LPA stimulates proliferation of ovarian cancer cells and has been proposed as an autocrine growth factor. Here, we show that a novel autocrine loop of LPA promotes the migration of ovarian cancer cells, which is a critical step of tumor metastasis. We report that laminin, but not other extracellular matrix proteins, induces LPA production in ovarian cancer cells. A neutralizing antibody against beta1 integrin and a calcium-independent phospholipase A2-specific inhibitor, HELSS, block both LPA production and the haptotactic activity of laminin. Exogenously added LPA restores the migratory ability of HEY ovarian cancer cells to laminin. These data suggest that laminin-induced cell migration is mediated by LPA. We further show that a specific receptor for LPA, LPA3, is required for mediating the chemotactic activity of LPA. In addition, we show that cytosolic PLA2 is required for cell migration and its activation is phosphatidylinositol-3 kinase-dependent. These findings have revealed a new mechanism of crosstalk between a beta1 integrin receptor and a G protein-coupled receptor.


Asunto(s)
Comunicación Autocrina , Movimiento Celular , Laminina/farmacología , Lisofosfolípidos/biosíntesis , Neoplasias Ováricas/fisiopatología , Movimiento Celular/efectos de los fármacos , Proteínas de la Matriz Extracelular/farmacología , Femenino , Subunidades alfa de la Proteína de Unión al GTP Gi-Go/fisiología , Fosfolipasas A2 Grupo VI , Humanos , Integrina beta1/fisiología , Lisofosfolípidos/farmacología , Modelos Biológicos , Neoplasias Ováricas/metabolismo , Toxina del Pertussis/farmacología , Fosfatidilinositol 3-Quinasas/fisiología , Fosfolipasas A/fisiología , Fosfolipasas A2 , Células Tumorales Cultivadas
4.
Cancer Epidemiol Biomarkers Prev ; 13(7): 1185-91, 2004 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15247129

RESUMEN

OBJECTIVE: To determine whether lysophosphatidic acid (LPA) and other lysophospholipids (LPL) are useful markers for diagnosis and/or prognosis of ovarian cancer in a controlled setting. METHOD: Plasma samples were collected from ovarian cancer patients and healthy control women in Hillsborough and Pinellas counties, Florida, and processed at the University of South Florida H. Lee Moffitt Cancer Center and Research Institute (Moffitt). Case patients with epithelial ovarian cancer (n = 117) and healthy control subjects (n = 27) participated in the study. Blinded LPL analysis, including 23 individual LPL species, was performed at the Cleveland Clinic Foundation using an electrospray ionization mass spectrometry-based method. LPL levels were transmitted to Moffitt, where clinical data were reviewed and statistical analyses were performed. RESULTS: There were statistically significant differences between preoperative case samples (n = 45) and control samples (n = 27) in the mean levels of total LPA, total lysophosphatidylinositol (LPI), sphingosine-1-phosphate (S1P), and individual LPA species as well as the combination of several LPL species. The combination of 16:0-LPA and 20:4-LPA yielded the best discrimination between preoperative case samples and control samples, with 93.1% correct classification, 91.1% sensitivity, and 96.3% specificity. In 22 cases with both preoperative and postoperative samples, the postoperative levels of several LPL, including S1P, total LPA, and lysophosphatidylcholine (LPC) levels and some individual species of LPA and LPC, were significantly different from preoperative levels. CONCLUSION: LPA, LPI, LPC, and S1P appear useful as diagnostic and prognostic biomarkers of ovarian cancer.


Asunto(s)
Biomarcadores de Tumor/sangre , Lisofosfolípidos/sangre , Neoplasias Ováricas/sangre , Esfingosina/análogos & derivados , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Lisofosfolípidos/clasificación , Persona de Mediana Edad , Estadificación de Neoplasias/clasificación , Neoplasias Glandulares y Epiteliales/sangre , Neoplasias Peritoneales/sangre , Espectrometría de Masa por Ionización de Electrospray , Esfingosina/sangre
5.
Artículo en Inglés | MEDLINE | ID: mdl-12570723

RESUMEN

Lysophospholipids (LPLs), including glycerol- and sphingoid-based lipids, stimulate cell signaling and play important pathophysiological roles in humans and other animals. These LPLs include lysophosphatidic acid (LPA), lysophosphatidylinositol (LPI), lysophosphatidylcholine (LPC), lysophosphatidylserine (LPS), sphingosine-1-phosphate (S1P), and sphingosylphosphorylcholine (SPC). Analyses of LPLs in human body fluids from subjects with different pathophysiological conditions reveal not only the relevance of LPLs in human diseases, but also their potential application as biomarkers and/or therapeutic targets. In recent years, the identification and/or characterization of the plasma membrane receptors for LPLs and enzymes regulating the metabolism of LPLs have greatly facilitated our understanding of their role and signaling properties. In vitro and in vivo functional and signaling studies have revealed the broad and potent biological effects of LPLs and the mechanisms of LPL actions in different cellular systems. Development of specific antagonists for each of the LPL receptors will provide powerful tools for dissecting signaling pathways mediated by receptor subtypes. More importantly, these antagonists may serve as therapeutics for relevant diseases. Genetic depletion of LPL receptors in mice has provided and will continue to provide critical information on the pathophysiological roles of LPL receptors. It is important to further evaluate the significance of targeting these bioactive LPL receptors, their downstream signaling molecules, and/or metabolic enzymes in the treatment of cancers and other diseases.


Asunto(s)
Lisofosfolípidos/fisiología , Transducción de Señal/fisiología , Animales , Biomarcadores/química , Humanos , Lisofosfolípidos/química , Lisofosfolípidos/metabolismo
6.
Hum Mol Genet ; 16(7): 837-47, 2007 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-17341491

RESUMEN

In the majority of neurodegenerative storage disorders, neuronal death in the brain is followed by infiltration of phagocytic cells (e.g. activated microglia, astroglia and macrophages) for the efficient removal of cell corpses. However, it is increasingly evident that these phagocytes may also cause death of adjoining viable neurons contributing to rapid progression of neurodegeneration. Infantile neuronal ceroid lipofuscinosis (INCL) is a devastating, neurodegenerative, lysosomal storage disorder caused by inactivating mutations in the palmitoyl-protein thioesterase-1 (PPT1) gene. PPT1 catalyzes the cleavage of thioester linkages in S-acylated (palmitoylated) proteins and its deficiency leads to abnormal accumulation of thioesterified polypeptides (ceroid) in lysosomes causing INCL pathogenesis. PPT1-knockout (PPT1-KO) mice mimic the clinical and pathological features of human INCL including rapid neuronal death by apoptosis and phagocyte infiltration. We previously reported that in PPT1-KO mice, the neurons undergo endoplasmic reticulum stress activating unfolded protein response, which mediates caspase-12 activation and apoptosis. However, the molecular mechanism(s) by which the phagocytic cells are recruited in the PPT1-KO mouse brain remains poorly understood. We report here that increased production of lysophosphatidylcholine (LPC), catalyzed by the activation of cytosolic phospholipase A(2) (cPLA(2)) in the PPT1-KO mouse brain, is a 'lipid signal' for phagocyte recruitment. We also report that an age-dependent increase in LPC levels in the PPT1-KO mouse brain positively correlates with elevated expression of the genes characteristically associated with phagocytes. We propose that increased cPLA(2)-catalyzed LPC production in the brain is at least one of the mechanisms that mediate phagocyte infiltration contributing to INCL neuropathology.


Asunto(s)
Encéfalo/metabolismo , Lisofosfatidilcolinas/metabolismo , Fagocitos/metabolismo , Fosfolipasas A/metabolismo , Tioléster Hidrolasas/genética , Animales , Western Blotting , Encéfalo/ultraestructura , Movimiento Celular , Activación Enzimática , Galectinas/metabolismo , Expresión Génica , Proteína Ácida Fibrilar de la Glía/metabolismo , Humanos , Inmunohistoquímica , Metabolismo de los Lípidos/fisiología , Ratones , Ratones Noqueados , Microscopía Electrónica de Transmisión , Modelos Biológicos , Fagocitos/citología , Reacción en Cadena de la Polimerasa , Transducción de Señal , Espectrometría de Masa por Ionización de Electrospray , Factores de Tiempo
7.
Hum Mol Genet ; 15(2): 337-46, 2006 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-16368712

RESUMEN

Numerous proteins undergo modification by palmitic acid (S-acylation) for their biological functions including signal transduction, vesicular transport and maintenance of cellular architecture. Although palmitoylation is an essential modification, these proteins must also undergo depalmitoylation for their degradation by lysosomal proteases. Palmitoyl-protein thioesterase-1 (PPT1), a lysosomal enzyme, cleaves thioester linkages in S-acylated proteins and removes palmitate residues facilitating the degradation of these proteins. Thus, inactivating mutations in the PPT1 gene cause infantile neuronal ceroid lipofuscinosis (INCL), a devastating neurodegenerative storage disorder of childhood. Although rapidly progressing brain atrophy is the most dramatic pathological manifestation of INCL, the molecular mechanism(s) remains unclear. Using PPT1-knockout (PPT1-KO) mice that mimic human INCL, we report here that the endoplasmic reticulum (ER) in the brain cells of these mice is structurally abnormal. Further, we demonstrate that the level of growth-associated protein-43 (GAP-43), a palmitoylated neuronal protein, is elevated in the brains of PPT1-KO mice. Moreover, forced expression of GAP-43 in PPT1-deficient cells results in the abnormal accumulation of this protein in the ER. Consistent with these results, we found evidence for the activation of unfolded protein response (UPR) marked by elevated levels of phosphorylated translation initiation factor, eIF2alpha, increased expression of chaperone proteins such as glucose-regulated protein-78 and activation of caspase-12, a cysteine proteinase in the ER, mediating caspase-3 activation and apoptosis. Our results, for the first time, link PPT1 deficiency with the activation of UPR, apoptosis and neurodegeneration in INCL and identify potential targets for therapeutic intervention in this uniformly fatal disease.


Asunto(s)
Apoptosis/genética , Lipofuscinosis Ceroideas Neuronales/genética , Lipofuscinosis Ceroideas Neuronales/metabolismo , Neuronas/patología , Tioléster Hidrolasas/deficiencia , Animales , Western Blotting , Encéfalo/metabolismo , Encéfalo/ultraestructura , Células Cultivadas , Cartilla de ADN , Retículo Endoplásmico/genética , Retículo Endoplásmico/metabolismo , Retículo Endoplásmico/patología , Factor 2 Eucariótico de Iniciación/metabolismo , Proteína GAP-43/metabolismo , Inmunoprecipitación , Ratones , Ratones Noqueados , Microscopía Electrónica de Transmisión , Microscopía Fluorescente , Chaperonas Moleculares/metabolismo , Neuronas/citología , Tritio
8.
Cell ; 113(6): 717-30, 2003 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-12809603

RESUMEN

Efficient engulfment of the intact cell corpse is a critical end point of apoptosis, required to prevent secondary necrosis and inflammation. The presentation of "eat-me" signals on the dying cell is an important part of this process of recognition and engulfment by professional phagocytes. Here, we present evidence that apoptotic cells secrete chemotactic factor(s) that stimulate the attraction of monocytic cells and primary macrophages. The activation of caspase-3 in the apoptotic cell was found to be required for the release of this chemotactic factor(s). The putative chemoattractant was identified as the phospholipid, lysophosphatidylcholine. Further analysis showed that lysophosphatidylcholine was released from apoptotic cells due to the caspase-3 mediated activation of the calcium-independent phospholipase A(2). These data suggest that in addition to eat-me signals, apoptotic cells display attraction signals to ensure the efficient removal of apoptotic cells and prevent postapoptotic necrosis.


Asunto(s)
Apoptosis/fisiología , Caspasas/metabolismo , Quimiotaxis/fisiología , Células Eucariotas/enzimología , Lisofosfatidilcolinas/metabolismo , Fagocitos/enzimología , Fagocitosis/fisiología , Animales , Repetición de Anquirina/genética , Células COS , Caspasa 3 , Extensiones de la Superficie Celular/metabolismo , Inhibidores Enzimáticos/farmacología , Células Eucariotas/metabolismo , Células HT29 , Humanos , Inflamación/enzimología , Metabolismo de los Lípidos , Ratones , Fagocitos/metabolismo , Fosfolipasas A/metabolismo , Inhibidores de la Síntesis de la Proteína/farmacología , Transducción de Señal/fisiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA