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1.
Environ Sci Pollut Res Int ; 30(41): 94976-94987, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37542692

RESUMEN

Sustainable investment is widely regarded as an important market-based approach to achieving inclusive green growth. To achieve the inclusive green growth objective, companies providing sustainable products must be profitable enough to attract private capital. Oil price changes can however affect the profitability of such companies. This study assesses volatility transmission between crude oil prices and sustainable investment in the USA. Using the dynamic conditional correlation-generalized autoregressive conditional heteroskedasticity (DCC-GARCH) method, daily data from September 28, 2012, to October 19, 2022, is analyzed. There are several key findings from this analysis. The risk connectedness of crude oil and sustainable investment is found to vary with time. Results further show that the risk connectedness increases in periods of important economic and geopolitical events. The greatest risk connectedness of crude oil and sustainable investment is observed during the outbreak of coronavirus disease (COVID-19). Moreover, the result shows that crude oil is the main risk transmitter, whereas, both the energy efficiency and pollution mitigation indices (i.e., sustainable investment) are risk receivers, and crude oil is constantly dominating sustainable investment. The study findings provide valuable insights for investors and policymakers alike.


Asunto(s)
COVID-19 , Petróleo , Estados Unidos , Humanos , Inversiones en Salud , Brotes de Enfermedades , Contaminación Ambiental , Receptor DCC
2.
J Neurosci ; 42(42): 7885-7899, 2022 10 19.
Artículo en Inglés | MEDLINE | ID: mdl-36028316

RESUMEN

Anterolateral system (AS) neurons transmit pain signals from the spinal cord to the brain. Their morphology, anatomy, and physiological properties have been extensively characterized and suggest that specific AS neurons and their brain targets are concerned with the discriminatory aspects of noxious stimuli, such as their location or intensity, and their motivational/emotive dimension. Among the recently unraveled molecular markers of AS neurons is the developmentally expressed transcription factor Phox2a, providing us with the opportunity to selectively disrupt the embryonic wiring of AS neurons to gain insights into the logic of their adult function. As mice with a spinal-cord-specific loss of the netrin-1 receptor deleted in colorectal carcinoma (DCC) have increased AS neuron innervation of ipsilateral brain targets and defective noxious stimulus localization or topognosis, we generated mice of either sex carrying a deletion of Dcc in Phox2a neurons. Such DccPhox2a mice displayed impaired topognosis along the rostrocaudal axis but with little effect on left-right discrimination and normal aversive responses. Anatomical tracing experiments in DccPhox2a mice revealed defective targeting of cervical and lumbar AS axons within the thalamus. Furthermore, genetic labeling of AS axons revealed their expression of DCC on their arrival in the brain, at a time when many of their target neurons are being born and express Ntn1 Our experiments suggest a postcommissural crossing function for netrin-1:DCC signaling during the formation of somatotopically ordered maps and are consistent with a discriminatory function of some of the Phox2a AS neurons.SIGNIFICANCE STATEMENT How nociceptive (pain) signals are relayed from the body to the brain remains an important question relevant to our understanding of the basic physiology of pain perception. Previous studies have demonstrated that the AS is a main effector of this function. It is composed of AS neurons located in the spinal cord that receive signals from nociceptive sensory neurons that detect noxious stimuli. In this study, we generate a genetic miswiring of mouse AS neurons that results in a decreased ability to perceive the location of a painful stimulus. The precise nature of this defect sheds light on the function of different kinds of AS neurons and how pain information may be organized.


Asunto(s)
Neoplasias Colorrectales , Factores de Crecimiento Nervioso , Animales , Ratones , Neoplasias Colorrectales/metabolismo , Receptor DCC/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Receptores de Netrina/metabolismo , Netrina-1 , Neuronas/fisiología , Dolor/metabolismo , Receptores de Superficie Celular/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Supresoras de Tumor/genética , Tálamo
3.
Sci Rep ; 9(1): 263, 2019 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-30670742

RESUMEN

Tumour sequencing identifies highly recurrent point mutations in cancer driver genes, but rare functional mutations are hard to distinguish from large numbers of passengers. We developed a novel computational platform applying a multi-modal approach to filter out passengers and more robustly identify putative driver genes. The primary filter identifies enrichment of cancer mutations in CATH functional families (CATH-FunFams) - structurally and functionally coherent sets of evolutionary related domains. Using structural representatives from CATH-FunFams, we subsequently seek enrichment of mutations in 3D and show that these mutation clusters have a very significant tendency to lie close to known functional sites or conserved sites predicted using CATH-FunFams. Our third filter identifies enrichment of putative driver genes in functionally coherent protein network modules confirmed by literature analysis to be cancer associated. Our approach is complementary to other domain enrichment approaches exploiting Pfam families, but benefits from more functionally coherent groupings of domains. Using a set of mutations from 22 cancers we detect 151 putative cancer drivers, of which 79 are not listed in cancer resources and include recently validated cancer associated genes EPHA7, DCC netrin-1 receptor and zinc-finger protein ZNF479.


Asunto(s)
Neoplasias/genética , Oncogenes/genética , Mapas de Interacción de Proteínas/genética , Biología Computacional/métodos , Receptor DCC/genética , Receptor DCC/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Bases de Datos Genéticas/estadística & datos numéricos , Conjuntos de Datos como Asunto , Humanos , Mutación Puntual , Mapeo de Interacción de Proteínas/métodos , Receptor EphA7/genética , Receptor EphA7/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
4.
J Ethnopharmacol ; 187: 123-33, 2016 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-27106785

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: You-Gui pills (YGPs) are an effective traditional Chinese formula being used clinically for the treatment of multiple sclerosis (MS). Previous studies demonstrated that YGPs exerted the potent neuroprotective effects in murine models of experimental autoimmune encephalomyelitis (EAE), which is an equivalent animal model for multiple sclerosis (MS). However, the mechanism of YGPs functions remained unclear. AIM OF THIS STUDY: The aim of this study was to evaluate the therapeutic effect of YGPs in MOG35-55-induced EAE mice and to further elucidate the underlying molecular mechanism. METHODS: Female C57BL/6 mice were divided into six groups, including the non-treated EAE model, prednisone acetate- and 1.2, 2.4 or 4.8g/kg YGPs-treated EAE groups, and a normal control group. The EAE model was established by injecting the mice subcutaneously with MOG35-55 antigen. The body weights were measured and the neurological functions were scored in each group. The pathology and morphology of the brain and spinal cord was examined. The expression of MAP-2 was detected by immunofluorescent staining. The levels of netrin1, DCC, RhoA, Rac1, and Cdc42 were assayed by immunohistochemistry, qRT-PCR and Western blot on day 40 post-immunization (PI). RESULTS: YGPs treatments significantly reduced neurological function scores in EAE mice, where the inflammatory infiltration was reduced and the axon and myelin damage in both brain and spinal cord was alleviated. In the brain and spinal cord tissues, YGPs increased the expression of neuronal factors MAP-2, netrin1 and DCC. The expression of Rac1 and Cdc42 were increased, while RhoA was reduced following YGPs treatments. CONCLUSION: Our results demonstrated that YGPs exhibited a neuroprotective effect on promoting nerve regeneration at the brain and spinal cord in EAE mice induced by MOG35-55. Netrin1, DCC and the Rho family GTPases of RhoA, Racl, Cdc42 were involved in mediating the effects of YGPs on nerve regeneration.


Asunto(s)
Medicamentos Herbarios Chinos/uso terapéutico , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Animales , Encéfalo/efectos de los fármacos , Encéfalo/patología , Encéfalo/ultraestructura , Receptor DCC , Medicamentos Herbarios Chinos/farmacología , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Femenino , Ratones Endogámicos C57BL , Microscopía Electrónica de Transmisión , Glicoproteína Mielina-Oligodendrócito , Factores de Crecimiento Nervioso/genética , Factores de Crecimiento Nervioso/metabolismo , Regeneración Nerviosa/efectos de los fármacos , Netrina-1 , Fármacos Neuroprotectores/farmacología , Fragmentos de Péptidos , Fitoterapia , ARN Mensajero/metabolismo , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Médula Espinal/efectos de los fármacos , Médula Espinal/patología , Médula Espinal/ultraestructura , Comprimidos , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Proteínas de Unión al GTP rho/genética , Proteínas de Unión al GTP rho/metabolismo
5.
EMBO Rep ; 16(7): 851-62, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25947198

RESUMEN

Controlling the axon growth rate is fundamental when establishing brain connections. Using the thalamocortical system as a model, we previously showed that spontaneous calcium activity influences the growth rate of thalamocortical axons by regulating the transcription of Robo1 through an NF-κB-binding site in its promoter. Robo1 acts as a brake on the growth of thalamocortical axons in vivo. Here, we have identified the Netrin-1 receptor DCC as an accelerator for thalamic axon growth. Dcc transcription is regulated by spontaneous calcium activity in thalamocortical neurons and activating DCC signaling restores normal axon growth in electrically silenced neurons. Moreover, we identified an AP-1-binding site in the Dcc promoter that is crucial for the activity-dependent regulation of this gene. In summary, we have identified the Dcc gene as a novel downstream target of spontaneous calcium activity involved in axon growth. Together with our previous data, we demonstrate a mechanism to control axon growth that relies on the activity-dependent regulation of two functionally opposed receptors, Robo1 and DCC. These two proteins establish a tight and efficient means to regulate activity-guided axon growth in order to correctly establish neuronal connections during development.


Asunto(s)
Axones/fisiología , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Tálamo/fisiología , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Animales , Axones/ultraestructura , Sitios de Unión , Calcio/metabolismo , Células Cultivadas , Receptor DCC , Embrión de Mamíferos , Regulación del Desarrollo de la Expresión Génica , Conos de Crecimiento/fisiología , Ratones , FN-kappa B/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Netrina-1 , Neuronas/fisiología , Regiones Promotoras Genéticas , Receptores de Superficie Celular/química , Transducción de Señal , Tálamo/citología , Tálamo/embriología , Proteínas Supresoras de Tumor/química
6.
Curr Biol ; 24(5): 494-508, 2014 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-24560577

RESUMEN

BACKGROUND: Guidance molecules are normally presented to cells in an overlapping fashion; however, little is known about how their signals are integrated to control the formation of neural circuits. In the thalamocortical system, the topographical sorting of distinct axonal subpopulations relies on the emergent cooperation between Slit1 and Netrin-1 guidance cues presented by intermediate cellular targets. However, the mechanism by which both cues interact to drive distinct axonal responses remains unknown. RESULTS: Here, we show that the attractive response to the guidance cue Netrin-1 is controlled by Slit/Robo1 signaling and by FLRT3, a novel coreceptor for Robo1. While thalamic axons lacking FLRT3 are insensitive to Netrin-1, thalamic axons containing FLRT3 can modulate their Netrin-1 responsiveness in a context-dependent manner. In the presence of Slit1, both Robo1 and FLRT3 receptors are required to induce Netrin-1 attraction by the upregulation of surface DCC through the activation of protein kinase A. Finally, the absence of FLRT3 produces defects in axon guidance in vivo. CONCLUSIONS: These results highlight a novel mechanism by which interactions between limited numbers of axon guidance cues can multiply the responses in developing axons, as required for proper axonal tract formation in the mammalian brain.


Asunto(s)
Axones/fisiología , Glicoproteínas de Membrana/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Receptores Inmunológicos/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Receptor DCC , Regulación del Desarrollo de la Expresión Génica , Técnicas In Vitro , Glicoproteínas de Membrana/genética , Ratones Mutantes , Ratones Transgénicos , Mutación , Factores de Crecimiento Nervioso/genética , Proteínas del Tejido Nervioso/genética , Netrina-1 , Técnicas de Cultivo de Órganos , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Receptores Inmunológicos/genética , Tálamo/citología , Tálamo/crecimiento & desarrollo , Tálamo/fisiología , Proteínas Supresoras de Tumor/genética , Proteínas Roundabout
7.
Cell Cycle ; 12(7): 1058-70, 2013 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-23435205

RESUMEN

Urothelial cell carcinoma (UCC) is the second most common genitourinary malignant disease in the USA, and tobacco smoking is the major known risk factor for UCC development. Exposure to carcinogens, such as those contained in tobacco smoke, is known to directly or indirectly damage DNA, causing mutations, chromosomal deletion events and epigenetic alterations in UCC. Molecular studies have shown that chromosome 9 alterations and P53, RAS, RB and PTEN mutations are among the most frequent events in UCC. Recent studies suggested that continuous tobacco carcinogen exposure drives and enhances the selection of epigenetically altered cells in UCC, predominantly in the invasive form of the disease. However, the sequence of molecular events that leads to UCC after exposure to tobacco smoke is not well understood. To elucidate molecular events that lead to UCC oncogenesis and progression after tobacco exposure, we developed an in vitro cellular model for smoking-induced UCC. SV-40 immortalized normal HUC1 human bladder epithelial cells were continuously exposed to 0.1% cigarette smoke extract (CSE) until transformation occurred. Morphological alterations and increased cell proliferation of non-malignant urothelial cells were observed after 4 months (mo) of treatment with CSE. Anchorage-independent growth assessed by soft agar assay and increase in the migratory and invasive potential was observed in urothelial cells after 6 mo of CSE treatment. By performing a PCR mRNA expression array specific to the PI3K-AKT pathway, we found that 26 genes were upregulated and 22 genes were downregulated after 6 mo of CSE exposure of HUC1 cells. Among the altered genes, PTEN, FOXO1, MAPK1 and PDK1 were downregulated in the transformed cells, while AKT1, AKT2, HRAS, RAC1 were upregulated. Validation by RT-PCR and western blot analysis was then performed. Furthermore, genome-wide methylation analysis revealed MCAM, DCC and HIC1 are hypermethylated in CSE-treated urothelial cells when compared with non-CSE exposed cells. The methylation status of these genes was validated using quantitative methylation-specific PCR (QMSP), confirming an increase in methylation of CSE-treated urothelial cells compared to untreated controls. Therefore, our findings suggest that a tobacco signature could emerge from distinctive patterns of genetic and epigenetic alterations and can be identified using an in vitro cellular model for the development of smoking-induced cancer.


Asunto(s)
Metilación de ADN , Genoma Humano , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Fumar , Carcinoma de Células Transicionales/metabolismo , Carcinoma de Células Transicionales/patología , Proteínas de Ciclo Celular , Línea Celular , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Transformación Celular Neoplásica/efectos de los fármacos , Receptor DCC , Regulación hacia Abajo/efectos de los fármacos , Proteína Forkhead Box O1 , Factores de Transcripción Forkhead/metabolismo , Humanos , Factores de Transcripción de Tipo Kruppel/genética , Factores de Transcripción de Tipo Kruppel/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Extractos Vegetales/farmacología , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Nicotiana/química , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Neoplasias de la Vejiga Urinaria/metabolismo , Neoplasias de la Vejiga Urinaria/patología
8.
J Comp Neurol ; 521(2): 312-25, 2013 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-22806432

RESUMEN

Ascending somatosensory pathways are crossed pathways representing each side of the body in the contralateral neocortex. The principal sensory nucleus of the trigeminal nerve (PrV) relays the facial sensations to the contralateral somatosensory cortex via the ventrobasal thalamus. In the companion article (Kivrak and Erzurumlu [2012] J. Comp. Neurol. 12-0013) we described the normal development of the trigeminal lemniscal pathway in the mouse. In this study we investigated the role of midline axon navigation signals, the netrin and slit proteins. In situ hybridization assays revealed that both netrin and slit mRNAs are expressed along the midline facing the PrV axons and their receptors are expressed in developing PrV neurons. In wild-type mouse embryos, PrV axons cross the midline and take a sharp rostral turn heading toward the contralateral thalamus. Examination of trigeminal lemniscal axons in dcc knockout mice revealed absence of midline crossing between E11 and E15. However, a few axons crossed the midline at E17 and reached the contralateral thalamus, resulting in a bilateral PrV lemniscal pathway at P0. We also found that slit1, -2 or -3 single or double knockout mice have impaired development of the trigeminal-lemniscal pathway. These include axon stalling along the midline, running within the midline, and recrossing of axons back to the site of origin. Collectively, our studies indicate a cooperative role for netrin and slit proteins in midline attraction and crossing behavior of the ascending facial somatosensory projections during development.


Asunto(s)
Factores de Crecimiento Nervioso/fisiología , Proteínas del Tejido Nervioso/fisiología , Vías Nerviosas/fisiología , Transducción de Señal/fisiología , Tálamo/fisiología , Núcleos del Trigémino/fisiología , Proteínas Supresoras de Tumor/fisiología , Animales , Axones/fisiología , Carbocianinas , Receptor DCC , Femenino , Regulación del Desarrollo de la Expresión Génica/fisiología , Hibridación in Situ , Péptidos y Proteínas de Señalización Intercelular/fisiología , Proteínas de la Membrana/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Netrina-1 , Vías Nerviosas/crecimiento & desarrollo , Embarazo , Sondas ARN , Receptores de Superficie Celular/biosíntesis , Receptores de Superficie Celular/genética , Receptores Inmunológicos/fisiología , Rombencéfalo/metabolismo , Rombencéfalo/fisiología , Núcleos del Trigémino/crecimiento & desarrollo , Proteínas Supresoras de Tumor/biosíntesis , Proteínas Supresoras de Tumor/genética , Proteínas Roundabout
9.
J Neurosci ; 31(4): 1489-99, 2011 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-21273433

RESUMEN

Endocannabinoids (eCBs) are retrograde neurotransmitters that modulate the function of many types of synapses. The presence of eCBs, their CB1 receptor (CB1R), and metabolizing enzymes at embryonic and early postnatal periods have been linked to developmental processes such as neuronal proliferation, differentiation, and migration, axon guidance, and synaptogenesis. Here, we demonstrate the presence of a functional eCB system in the developing visual system and the role of CB1R during axon growth and retinothalamic development. Pharmacological treatment of retinal explants and primary cortical neuron cultures with ACEA, a selective CB1R agonist, induced a collapse of the growth cone (GC). Furthermore the application of AM251, a CB1R inverse agonist, to the neuronal cultures increased the surface area of GC. In vivo, intraocular injection of ACEA diminished retinal projection growth, while AM251 promoted growth and caused aberrant projections. In addition, compared with their wild-type littermates, CB1R-deficient adult mice revealed a lower level of eye-specific segregation of retinal projections in the dorsal lateral geniculate nucleus. Finally, we found that pharmacological modulation of CB1R affected the trafficking of Deleted in colorectal cancer (DCC) receptor to the plasma membrane in a PKA-dependent manner. Moreover, pharmacological inhibition or genetic inactivation of DCC abolished the CB1R-induced reorganization of the GC. Overall, these findings establish a mechanism by which the CB1R influences GC behavior and nervous system development in concerted action with DCC.


Asunto(s)
Axones/fisiología , Neuronas/metabolismo , Receptor Cannabinoide CB1/fisiología , Receptores de Superficie Celular/fisiología , Retina/metabolismo , Proteínas Supresoras de Tumor/fisiología , Animales , Moduladores de Receptores de Cannabinoides/metabolismo , Membrana Celular/metabolismo , Células Cultivadas , AMP Cíclico/fisiología , Proteínas Quinasas Dependientes de AMP Cíclico/fisiología , Receptor DCC , Agonismo Inverso de Drogas , Conos de Crecimiento/fisiología , Técnicas In Vitro , Ratones , Ratones Noqueados , Neurotransmisores/metabolismo , Transporte de Proteínas , Receptor Cannabinoide CB1/agonistas , Receptor Cannabinoide CB1/genética , Retina/embriología , Células Ganglionares de la Retina/metabolismo , Células Ganglionares de la Retina/ultraestructura , Tálamo/embriología , Tálamo/metabolismo
10.
J Neurosci Res ; 87(7): 1620-33, 2009 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-19115401

RESUMEN

Early events in the axonal tract formation from mammillary bodies remain poorly understood. In the present study, we reported an aberrant pattern of axonal projections from mammillary bodies to the dorsal thalamus in mice lacking the transcription factor Pax6. We found that Netrin-1 was ectopically up-regulated and that both Slit1 and Slit2 were down-regulated in the presumptive dorsal thalamus of Pax6 mutant mice. We then examined the effects of Netrin-1 and Slit2 on the mammillary axons by in utero electroporation techniques. Netrin-1 had an attractive action toward the mammillary axons. Moreover, mammillary trajectories were disorganized in Netrin-1-deficient mice. On the other hand, Slit2 had a repulsive effect on the mammillary axons. These findings suggest that the combination of Netrin and Slit may be involved in proper axonal projection from the mammillary bodies and that their misexpression in the diencephalon may cause the misrouting of these axons in Pax6 mutant mice.


Asunto(s)
Axones/ultraestructura , Proteínas del Ojo/genética , Proteínas de Homeodominio/genética , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Tubérculos Mamilares/embriología , Factores de Crecimiento Nervioso/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Factores de Transcripción Paired Box/genética , Proteínas Represoras/genética , Tálamo/embriología , Proteínas Supresoras de Tumor/metabolismo , Animales , Quimiotaxis/fisiología , Receptor DCC , Proteínas del Ojo/metabolismo , Regulación de la Expresión Génica , Proteínas de Homeodominio/metabolismo , Técnicas In Vitro , Proteínas de la Membrana/metabolismo , Ratones , Ratones Noqueados , Ratones Mutantes , Factores de Crecimiento Nervioso/genética , Netrina-1 , Vías Nerviosas/embriología , Factor de Transcripción PAX6 , Factores de Transcripción Paired Box/metabolismo , ARN Mensajero/metabolismo , Receptores de Superficie Celular/metabolismo , Receptores Inmunológicos/metabolismo , Proteínas Represoras/metabolismo , Proteínas Supresoras de Tumor/genética , Proteínas Roundabout
11.
Front Biosci ; 9: 2725-32, 2004 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-15353309

RESUMEN

Mortality from colorectal cancer, a leading cause of death in the U.S.A. and other western countries, has remained unchanged over the past 45 years. Therefore, the search for strategies to prevent the development and progression of colorectal cancer has markedly intensified. Chemoprevention is one such strategy. Accumulating evidence suggests that folic acid, a water soluble vitamin, could be an effective chemopreventive agent for colorectal cancer. Results from several studies have demonstrated that a diet deficient in folic acid may be associated with an increased risk of colonic neoplasia, whereas dietary supplementation of this nutrient may be chemopreventive. Although the mechanisms by which folic acid exerts its chemopreventive role in colorectal carcinogenesis remain to be fully elucidated, supplemental folic acid has been shown to arrest the loss of heterozygosity (LOH) of the tumor suppressor gene DCC (deleted in colorectal cancer) and to stabilize its protein in normal appearing rectal mucosa of patients with colorectal adenomas. Data from in vitro studies utilizing colon cancer cell lines suggest that supplemental folic acid or its metabolite 5-methyltetrahydrofolate (5-MTF) attenuates the expression and activation of EGF-receptor (EGFR) as well as proliferation of cells. The folic acid mediated reduction of EGFR function could partly be the result of suppression of EGFR gene through increased methylation of CpG sequences within its promoter.


Asunto(s)
Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/prevención & control , Ácido Fólico/farmacología , Animales , Línea Celular Tumoral , Proliferación Celular , Islas de CpG , Receptor DCC , Metilación de ADN , Receptores ErbB/metabolismo , Humanos , Pérdida de Heterocigocidad , Receptores de Superficie Celular/genética , Proteínas Supresoras de Tumor/genética
12.
Dis Colon Rectum ; 47(7): 1216-24, 2004 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15148649

RESUMEN

PURPOSE: The deleted in colorectal cancer (DCC) gene predicts a poor outcome for patients with colorectal carcinoma. This study was designed to investigate whether the expression of the DCC protein also can predict response to adjuvant chemotherapy. METHODS: The expression of DCC was evaluated immunohistochemically in 74 paraffin-embedded tumor samples from patients with Stage II (n = 41) and Stage III (n = 33) colorectal carcinomas. Follow-up time was at least 60 (median, 64) months. Follow-up was at least five years for all patients who are alive. End points of the study were recurrence of disease and death. Forty-eight patients received adjuvant therapy of 5-fluorouracil + levamisole; 28 were not treated. RESULTS: Fifty percent of tumors were deleted in colorectal cancer-positive (DCC+). Proportion of survival and disease-free survival were higher in the DCC+ patients (83 percent) than in deleted in colorectal cancer-negative (DCC-; 54 percent). In the DCC+ group, adjuvant treatment was a strong positive predictive factor for survival and disease-free survival. All DCC+ patients who received adjuvant chemotherapy (CHEMO+) are alive with no evidence of disease, whereas without chemotherapy (CHEMO-) only 54 percent are alive ( P = 0.0001). When stratification was performed by stage, patients in Stage II who were DCC+/CHEMO+ had survival and disease-free survival of 100 percent, whereas in DCC+/CHEMO- survival rate was 75 percent and disease-free survival rate 62 percent ( P = 0.042). Patients in Stage III who were DCC+/ CHEMO+ had survival and disease-free survival of 100 percent, whereas in DCC+/CHEMO- both dropped to zero ( P = 0.0002). On the other hand, in the DCC- tumors, there was no statistical significant relationship between chemotherapy and survival or disease-free survival (DCC-/CHEMO- had 57 percent survival; DCC-/CHEMO+ had 52 percent survival). CONCLUSIONS: DCC is a prognostic factor for colorectal cancer. Positive expression of DCC identifies a subgroup of patients who respond favorably to adjuvant chemotherapy, which resulted in our cases, in 100 percent survival and disease-free survival rates. Without treatment, the survival rate of DCC+ patients dropped significantly. We suggest that DCC immunostaining should be performed routinely. All DCC+ patients should receive adjuvant chemotherapy. For DCC- tumors, a larger cohort of patients should be studied before definitive conclusions can be drawn; however, clinical trials of new drug combinations should focus on DCC- patients.


Asunto(s)
Carcinoma/metabolismo , Moléculas de Adhesión Celular/biosíntesis , Neoplasias Colorrectales/metabolismo , Recurrencia Local de Neoplasia , Proteínas Supresoras de Tumor/biosíntesis , Adyuvantes Inmunológicos/uso terapéutico , Anciano , Antimetabolitos Antineoplásicos/uso terapéutico , Carcinoma/patología , Carcinoma/terapia , Quimioterapia Adyuvante , Colectomía , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/terapia , Receptor DCC , Femenino , Fluorouracilo/uso terapéutico , Humanos , Levamisol/uso terapéutico , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Valor Predictivo de las Pruebas , Receptores de Superficie Celular , Análisis de Supervivencia , Resultado del Tratamiento
13.
Cancer Detect Prev ; 27(4): 297-304, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12893078

RESUMEN

Loss of heterozygosity (LOH) and/or inactivation of tumor suppressor genes are implicated in the initiation and progression of many malignancies, including colorectal cancer. Although accumulating evidence suggests a chemopreventive role for folate in colorectal cancer, regulatory mechanisms are poorly understood. The primary objective of the current investigation was to determine whether folic acid would prevent LOH of the three tumor suppressor genes, deleted in colorectal cancer (DCC), adenomatous polyposis coli (APC) and p53 in macroscopically normal appearing rectal mucosa of patients with adenomatous polyps. In addition, the effect of folic acid on rectal mucosal proliferation was determined. Twenty patients were randomized in a double-blind study to receive either folic acid 5mg once daily or identical placebo tablets for 1 year. Genomic DNA and total protein were extracted from the rectal mucosa at baseline and after 1 year of treatment and analyzed for LOH and protein levels of APC, DCC and p53 genes. In addition, paraffin-embedded mucosal specimens were analyzed for proliferating cell nuclear antigen (PCNA) immunoreactivity, as a measure of cellular proliferative activity. Folate supplementation prevented LOH of DCC gene in five out of five (100%) patients who demonstrated baseline heterozygosity, whereas two out of four (50%) placebo-treated patients with baseline heterozygosity demonstrated allelic loss. Mucosal protein levels of DCC were also reduced in 7 of 10 (70%) placebo-treated patients compared to only 2 of 10 (20%) of patients treated with folate. Levels increased, however, in eight and three patients in the folic acid and placebo groups, respectively (P<0.02). Folic acid caused no change in allelic status of either APC or p53 gene. Folate supplementation caused a small, but not statistically significant, 16% reduction in mucosal proliferation, whereas placebo treatment resulted in a 88% (P<0.05) increase in this parameter, when compared with the corresponding baseline values. Our results indicate that folic acid prevents an increase in proliferation and arrests LOH of DCC gene and also stabilizes its protein in normal appearing rectal mucosa of patients with colorectal adenomas. Taken together, our data suggest that one of the ways folate may exert its chemopreventive effect is by stabilizing certain tumor suppressor gene(s) and preventing further increases in proliferation.


Asunto(s)
Adenoma/genética , Adenoma/prevención & control , Proteína de la Poliposis Adenomatosa del Colon/genética , Moléculas de Adhesión Celular/genética , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/prevención & control , Ácido Fólico/farmacología , Genes p53/genética , Hematínicos/farmacología , Pérdida de Heterocigocidad , Proteínas Supresoras de Tumor/genética , Adenoma/etiología , Administración Oral , Anciano , División Celular , Neoplasias Colorrectales/etiología , Receptor DCC , ADN de Neoplasias , Método Doble Ciego , Femenino , Humanos , Mucosa Intestinal , Masculino , Persona de Mediana Edad , Placebos , Receptores de Superficie Celular
14.
J Neurosci ; 19(22): 9900-12, 1999 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-10559399

RESUMEN

Optic nerve formation in mouse involves interactions between netrin-1 at the optic disk and the netrin-1 receptor DCC (deleted in colorectal cancer) expressed on retinal ganglion cell (RGC) axons. Deficiency in either protein causes RGC pathfinding defects at the disk leading to optic nerve hypoplasia (). Here we show that further along the visual pathway, RGC axons in netrin-1- or DCC-deficient mice grow in unusually angular trajectories within the ventral hypothalamus. In heterozygous Sey(neu) mice that also have a small optic nerve, RGC axon trajectories appear normal, indicating that the altered RGC axon trajectories in netrin-1 and DCC mutants are not secondarily caused by optic nerve hypoplasia. Intrinsic hypothalamic patterning is also affected in netrin-1 and DCC mutants, including a severe reduction in the posterior axon projections of gonadotropin-releasing hormone neurons. In addition to axon pathway defects, antidiuretic hormone and oxytocin neurons are found ectopically in the ventromedial hypothalamus, apparently no longer confined to the supraoptic nucleus in mutants. In summary, netrin-1 and DCC, presumably via direct interactions, govern both axon pathway formation and neuronal position during hypothalamic development, and loss of netrin-1 or DCC function affects both visual and neuroendocrine systems. Netrin protein localization also indicates that unlike in more caudal CNS, guidance about the hypothalamic ventral midline does not require midline expression of netrin.


Asunto(s)
Moléculas de Adhesión Celular/fisiología , Proteínas de Homeodominio , Hipotálamo/fisiología , Factores de Crecimiento Nervioso/fisiología , Neuronas/fisiología , Nervio Óptico/fisiología , Receptores de Superficie Celular/fisiología , Células Ganglionares de la Retina/fisiología , Proteínas Supresoras de Tumor , Vías Visuales/fisiología , Hormona Adrenocorticotrópica/sangre , Animales , Animales Recién Nacidos , Transporte Axonal , Axones/fisiología , Moléculas de Adhesión Celular/genética , Receptor DCC , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/fisiología , Desarrollo Embrionario y Fetal , Proteínas del Ojo , Femenino , Proteína GAP-43/deficiencia , Proteína GAP-43/genética , Proteína GAP-43/fisiología , Regulación del Desarrollo de la Expresión Génica , Genes DCC , Hormona del Crecimiento/sangre , Hipotálamo/anomalías , Hipotálamo/embriología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factores de Crecimiento Nervioso/deficiencia , Factores de Crecimiento Nervioso/genética , Receptores de Netrina , Netrina-1 , Neuronas/patología , Quiasma Óptico/embriología , Quiasma Óptico/fisiología , Nervio Óptico/anomalías , Factor de Transcripción PAX6 , Factores de Transcripción Paired Box , Receptores de Superficie Celular/deficiencia , Receptores de Superficie Celular/genética , Proteínas Represoras , Células Ganglionares de la Retina/patología , Vías Visuales/embriología
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