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1.
J Autoimmun ; 140: 103112, 2023 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-37742509

RESUMEN

Transaldolase deficiency predisposes to chronic liver disease progressing from cirrhosis to hepatocellular carcinoma (HCC). Transition from cirrhosis to hepatocarcinogenesis depends on mitochondrial oxidative stress, as controlled by cytosolic aldose metabolism through the pentose phosphate pathway (PPP). Progression to HCC is critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Although AR inactivation blocked susceptibility to hepatocarcinogenesis, it enhanced growth restriction, carbon trapping in the non-oxidative branch of the PPP and failed to reverse the depletion of glucose 6-phosphate (G6P) and liver cirrhosis. Here, we show that inactivation of the TAL-AR axis results in metabolic stress characterized by reduced mitophagy, enhanced overall autophagy, activation of the mechanistic target of rapamycin (mTOR), diminished glycosylation and secretion of paraoxonase 1 (PON1), production of antiphospholipid autoantibodies (aPL), loss of CD161+ NK cells, and expansion of CD38+ Ito cells, which are responsive to treatment with rapamycin in vivo. The present study thus identifies glycosylation and secretion of PON1 and aPL production as mTOR-dependent regulatory checkpoints of autoimmunity underlying liver cirrhosis in TAL deficiency.

2.
Rhinology ; 58(6): 574-580, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32662778

RESUMEN

BACKGROUND: The aim of this study was to compare olfactory function change in patients who underwent endoscopic skull-base surgery. METHODOLOGY: A total of 928 patients were included in this retrospective study. Olfactory function was measured using the non- validated Likert scale (0â€"100), the Cross-Cultural Smell Identification Test (CC-SIT) and the butanol threshold test (BTT). Patients were divided into two groups: an endoscopic trans-sellar approach group (ETA, n = 768) and an extended endoscopic endonasal approach group (EEEA, n = 160). The ETA group was sub-divided into Nasoseptal flap (NSF) and no NSF groups. RESULTS: Non-validated olfactory function significantly worsened in the EEEA and ETA-NSF groups compared with that in the ETA- no NSF group for at least 6 months post-operatively. Validated olfactory impairment (BTT and CC-SIT) was also significantly worse in the EEEA and NSF groups compared with that in the ETA-no NSF group 3 months post-operatively. Additionally, the degrees of non-validated and validated olfactory deterioration were not significantly different between the EEEA and ETA-NSF groups. We also found that CC-SIT score changes were significantly impaired in tuberculum sellae meningioma patients than in craniopharyn- gioma patients. CONCLUSIONS: We conclude that NSF was the key factor that led to olfactory impairment after endoscopic skull-base surgery.


Asunto(s)
Trastornos del Olfato , Procedimientos de Cirugía Plástica , Humanos , Trastornos del Olfato/etiología , Estudios Retrospectivos , Factores de Riesgo , Base del Cráneo/cirugía , Olfato
3.
Neuropathol Appl Neurobiol ; 43(7): 584-603, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28235153

RESUMEN

AIMS: The leucine-rich repeat kinase 2 (LRRK2) G2019S mutation is the most common genetic cause of Parkinson's disease (PD). There is compelling evidence that PD is not only a brain disease but also a gastrointestinal disorder; nonetheless, its pathogenesis remains unclear. We aimed to develop human neural and intestinal tissue models of PD patients harbouring an LRRK2 mutation to understand the link between LRRK2 and PD pathology by investigating the gene expression signature. METHODS: We generated PD patient-specific induced pluripotent stem cells (iPSCs) carrying an LRRK2 G2019S mutation (LK2GS) and then differentiated into three-dimensional (3D) human neuroectodermal spheres (hNESs) and human intestinal organoids (hIOs). To unravel the gene and signalling networks associated with LK2GS, we analysed differentially expressed genes in the microarray data by functional clustering, gene ontology (GO) and pathway analyses. RESULTS: The expression profiles of LK2GS were distinct from those of wild-type controls in hNESs and hIOs. The most represented GO biological process in hNESs and hIOs was synaptic transmission, specifically synaptic vesicle trafficking, some defects of which are known to be related to PD. The results were further validated in four independent PD-specific hNESs and hIOs by microarray and qRT-PCR analysis. CONCLUSION: We provide the first evidence that LK2GS also causes significant changes in gene expression in the intestinal cells. These hNES and hIO models from the same genetic background of PD patients could be invaluable resources for understanding PD pathophysiology and for advancing the complexity of in vitro models with 3D expandable organoids.


Asunto(s)
Células Madre Pluripotentes Inducidas/metabolismo , Mucosa Intestinal/metabolismo , Proteína 2 Quinasa Serina-Treonina Rica en Repeticiones de Leucina/genética , Neuronas/metabolismo , Organoides/metabolismo , Enfermedad de Parkinson/genética , Adulto , Diferenciación Celular , Femenino , Expresión Génica , Ontología de Genes , Genoma , Humanos , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/fisiología , Intestinos/citología , Masculino , Persona de Mediana Edad , Mutación , Neuronas/citología , Organoides/citología
4.
Rhinology ; 54(4): 336-341, 2016 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-27213721

RESUMEN

BACKGROUND: Acute invasive fungal rhinosinusitis (AIFR) is an aggressive opportunistic infection with a high mortality rate. Recently, non-invasive techniques have been introduced for diagnosis of invasive fungal disease. The purpose of this study is to evaluate the diagnostic significance of serum galactomannan measurement in patients with AIFR. METHODOLOGY: We conducted a retrospective case-control study of 28 patients with AIFR and 36 fungus ball (FB) patients. We evaluated clinical, laboratory, and pathologic findings along with disease course. RESULTS: In 28 patients with AIFR, there were 21 cases of invasive aspergillosis (IA) and 7 cases of invasive mucormycosis (IM). The control group was comprised of 36 patients with FB. The three-group analysis showed a statistically significant difference among the groups. At the cut-off value of 0.48, the sensitivity and specificity were 71.4% and 93.0%, respectively. Comparison of mean serum galactomannan levels in 5 non-survivors and 9 survivors at initial measurement showed no significant difference, but that became significantly different 1 week later. Statistical analysis showed that the levels of serum galactomannan decreased significantly according to the measurement-point in within survivor-group analysis. The difference in between survivor-groups analysis was also significant. CONCLUSION: Serum galactomannan measurement seems useful for early diagnosis and discrimination of fungal species in patients with AIFR. In addition, clinical outcomes may be related to the levels and patterns of serum galactomannan, especially in IA. The appropriate measurement of galactomannan might be helpful in treating the patients at high risk for AIFR.


Asunto(s)
Aspergilosis/sangre , Infecciones Fúngicas Invasoras/sangre , Mananos/sangre , Mucormicosis/sangre , Rinitis/sangre , Sinusitis/sangre , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Aspergilosis/diagnóstico , Estudios de Casos y Controles , Niño , Femenino , Galactosa/análogos & derivados , Humanos , Infecciones Fúngicas Invasoras/diagnóstico , Masculino , Persona de Mediana Edad , Mucormicosis/diagnóstico , Estudios Retrospectivos , Rinitis/diagnóstico , Sensibilidad y Especificidad , Sinusitis/diagnóstico , Adulto Joven
5.
Osteoarthritis Cartilage ; 23(4): 516-24, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25463446

RESUMEN

Mounting evidence suggests reconceptualizing osteoarthritis (OA) as an inflammatory disorder. Trauma and obesity, the common risk factors of OA, could trigger the local or systemic inflammatory cytokines cascade. Inflammatory bone loss has been well documented; yet it remains largely unknown about the link between the inflammation and hypertrophic changes of subchondral bone seen in OA, such as osteophytosis and sclerosis. Amid a cohort of inflammatory cytokines, endothelin-1 (ET-1) could stimulate the osteoblast-mediated bone formation in both physiological (postnatal growth of trabecular bone) and pathological conditions (bone metastasis of prostate or breast cancer). Also, ET-1 is known as a mitogen and contributes to fibrosis in various organs, e.g., skin, liver, lung, kidney heart and etc., as a result of inflammatory or metabolic disorders. Subchondral bone sclerosis shared the similarity with fibrosis in terms of the overproduction of collagen type I. We postulated that ET-1 might have a hand in the subchondral bone sclerosis of OA. Meanwhile, ET-1 was also able to stimulate the production of matrix metalloproteinase (MMP)-1 and 13 by articular chondrocytes and synoviocytes, by which it might trigger the enzymatic degradation of articular cartilage. Taken together, ET-1 signaling may play a role in destruction of bone-cartilage unit in the pathogenesis of OA; it warrants further investigations to potentiate ET-1 as a novel diagnostic biomarker and therapeutic target for rescue of OA.


Asunto(s)
Cartílago/fisiopatología , Endotelina-1/fisiología , Osteoartritis/etiología , Osteoartritis/fisiopatología , Osteogénesis/fisiología , Esclerosis/fisiopatología , Remodelación Ósea/fisiología , Condrocitos/fisiología , Citocinas/fisiología , Humanos , Metaloproteinasa 1 de la Matriz/fisiología , Metaloproteinasa 13 de la Matriz/fisiología , Transducción de Señal/fisiología
6.
J Neurol Neurosurg Psychiatry ; 86(3): 341-3, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24970905

RESUMEN

OBJECTIVES: Hyperekplexia is predominantly caused by mutations in the α-1 subunit of the inhibitory glycine receptor (GLRA1). Three quarters of cases show autosomal-recessive inheritance. METHODS: We carefully ascertained reports of ethnicity from our hyperekplexia research cohort. These were compared with all published cases of hyperekplexia with an identified genetic cause. Ethnicities were subgrouped as Caucasian, Asian, Arabic, Turkish, Jewish or Afro-American. RESULTS: We report the ethnicity of 90 cases: 56 cases from our service augmented by 34 cases from the literature. Homozygous deletions of exons 1 to 7 are predominantly seen in people with Turkish backgrounds (n=16/17, p<0.001). In contrast, the dominant point mutation R271 is seen in people of Asian, Caucasian and African-American heritage (n=19) but not in people with Arab or Turkish ethnicities (p<0.001). CONCLUSIONS: Self-declared ethnicity can predict gene-screening outcomes. Cultural practices influence the inheritance patterns and a Caucasian founder is postulated for R271 mutations.


Asunto(s)
Etnicidad/genética , Genotipo , Receptores de Glicina/genética , Síndrome de la Persona Rígida/etnología , Síndrome de la Persona Rígida/genética , Deleción Cromosómica , Estudios de Cohortes , Comparación Transcultural , Análisis Mutacional de ADN , Exones/genética , Frecuencia de los Genes/genética , Genes Dominantes/genética , Genes Recesivos/genética , Tamización de Portadores Genéticos , Homocigoto , Humanos , Mutación Puntual/genética
7.
Mol Psychiatry ; 19(2): 159-67, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24393807

RESUMEN

Alzheimer's disease (AD) and vascular dementia are the major causes of cognitive disorders worldwide. They are characterized by cognitive impairments along with neuropsychiatric symptoms, and that their pathogeneses show overlapping multifactorial mechanisms. Although AD has long been considered the most common cause of dementia, individuals afflicted with AD commonly exhibit cerebral vascular abnormalities. The concept of mixed dementia has emerged to more clearly identify patients with neurodegenerative phenomena exhibiting both AD and cerebral vascular pathologies-vascular damage along with ß-amyloid (Aß)-associated neurotoxicity and τ-hyperphosphorylation. Cognitive impairment has long been commonly explained through a 'neuro-centric' perspective, but emerging evidence has shed light over the important roles that neurovascular unit dysfunction could have in neuronal death. Moreover, accumulating data have been demonstrating astrocytes being the essential cell type in maintaining proper central nervous system functioning. In relation to dementia, the roles of astrocytes in Aß deposition and clearance are unclear. This article emphasizes the multiple events triggered by ischemia and the cytotoxicity exerted by Aß either alone or in association with endothelin-1 and receptor for advanced glycation end products, thereby leading to neurodegeneration in an 'astroglio-centric' perspective.


Asunto(s)
Enfermedad de Alzheimer/fisiopatología , Astrocitos/fisiología , Demencia Vascular/fisiopatología , Péptidos beta-Amiloides/metabolismo , Animales , Encéfalo/fisiopatología , Isquemia Encefálica/fisiopatología , Endotelina-1/metabolismo , Humanos
12.
Rhinology ; 52(3): 238-45, 2014 09.
Artículo en Inglés | MEDLINE | ID: mdl-25271529

RESUMEN

BACKGROUND: Extraocular muscle (EOM) injury is a rare but serious complication of endoscopic sinus surgery (ESS). The aim of this study is to describe the clinical characteristics and course of EOM injury occurring during ESS. DESIGN: Retrospective case series. METHODS: Medical records and CT images of patients who suffered from EOM injury after ESS between 2006 and 2012 were retrospectively reviewed. Patient demographics, endoscopic anatomy, type of surgery (primary or revision), predisposing risk factors, site and extent of injury on CT imaging, and associated complications were evaluated. In addition, data regarding ophthalmologic management and clinical outcomes were collected. RESULTS: Ten patients with EOM injuries after ESS were included in this study. One patient was undergoing revision ESS. All patients sustained medial rectus muscle injury and one patient suffered concurrent ipsilateral inferior rectus muscle injury. A microdebrider was used in nine cases. Right-sided injury (90% of patients) was more prevalent than left-sided injury, and 70% of injured medial rectus muscles were completely transected. After subsequent strabismus surgery, 8/9 patients regained binocular single vision in primary gaze despite residual diplopia in some gaze positions. CONCLUSION: Although proper ophthalmologic surgery after EOM injury may improve deviation in the primary gaze position, none of the patients regained normal EOM movement. Therefore, prevention of this complication through adequate surgical technique and precautions is important.


Asunto(s)
Endoscopía/efectos adversos , Músculos Oculomotores/lesiones , Senos Paranasales/cirugía , Adulto , Diplopía/etiología , Diplopía/cirugía , Endoscopía/instrumentación , Infecciones Fúngicas del Ojo/cirugía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Rinitis/cirugía , Factores de Riesgo , Sinusitis/cirugía , Estrabismo/etiología , Estrabismo/cirugía , Adulto Joven
13.
Rhinology ; 51(3): 275-9, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23943737

RESUMEN

BACKGROUND: Outfracture of the inferior turbinate (IT) presents numerous advantages, but it is generally believed that the lateralized IT will resume its original position. The purpose of this study was to evaluate the outcome of IT outfracture objectively using computed tomography (CT). METHODOLOGY: Fifteen patients who underwent bilateral IT outfracture for the removal of pituitary adenomas by the endonasal approach were enrolled. The angles between the lateral wall of the nasal cavity (NC) and IT on both sides were measured from CT scans before and at least 6 months after operation. In addition, we evaluated the effects of variables including age, thickness of IT attachment site and width of the nasal floor, on the angles. RESULTS: Regardless of the side where a Hardy retractor was placed, the angle between the lateral wall of the NC and IT decreased significantly within 6 months after the outfracture compared to preoperative values on both sides. Other variables showed no significant correlations with the angle between the IT and the lateral wall of the NC. CONCLUSION: The outfracture procedure effectively lateralized the IT and it maintained that position for at least 6 months after the operation.


Asunto(s)
Adenoma/cirugía , Endoscopía , Neoplasias Hipofisarias/cirugía , Tomografía Computarizada por Rayos X , Cornetes Nasales/diagnóstico por imagen , Cornetes Nasales/cirugía , Adulto , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Estadísticas no Paramétricas , Resultado del Tratamiento
14.
Nat Metab ; 5(1): 41-60, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36658399

RESUMEN

Oxidative stress modulates carcinogenesis in the liver; however, direct evidence for metabolic control of oxidative stress during pathogenesis, particularly, of progression from cirrhosis to hepatocellular carcinoma (HCC), has been lacking. Deficiency of transaldolase (TAL), a rate-limiting enzyme of the non-oxidative branch of the pentose phosphate pathway (PPP), restricts growth and predisposes to cirrhosis and HCC in mice and humans. Here, we show that mitochondrial oxidative stress and progression from cirrhosis to HCC and acetaminophen-induced liver necrosis are critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Both TAL and AR are confined to the cytosol; however, their inactivation distorts mitochondrial redox homeostasis in opposite directions. The results suggest that AR acts as a rheostat of carbon recycling and NADPH output of the PPP with broad implications for disease progression from cirrhosis to HCC.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Animales , Ratones , Carcinoma Hepatocelular/patología , Citosol/patología , NADP , Neoplasias Hepáticas/patología , Carcinogénesis/patología , Cirrosis Hepática/patología
15.
Int Nurs Rev ; 59(3): 369-75, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22897188

RESUMEN

PURPOSE: The purpose of this study was to develop effective intervention programmes that can reduce family caregiver burden as they provide care to stroke patients so that family caregivers can adapt to and deal with the new circumstances from the early stages of stroke. We also intended to verify the effectiveness of the developed programme. METHODS: This study employed a quasi-experimental design with a repeated-measures analysis. We included five hospitals specialized in stroke care in Seoul Metropolitan areas. Seventy-three patients from these hospitals agreed to participate in this study. RESULTS: The score of family caregiver burden decreased by 8.07 (±18.67) in the experimental group and increased by 1.65 (±7.47) in the control group, which was a significant difference (t=2.257, P=0.027) between pre- and post-intervention. The family caregiver burden of experimental group was significantly lower than the control group (F=3.649, P=0.033). CONCLUSIONS: The home-based individual tele-care intervention, in addition to the hospital-based group programme, was cost-effective and supportive in reducing family caregivers' burden by providing relevant information for their needs in timely manner.


Asunto(s)
Cuidadores/psicología , Consejo , Atención Domiciliaria de Salud , Accidente Cerebrovascular/terapia , Teléfono , Adulto , Anciano , Anciano de 80 o más Años , Hospitales de Enseñanza , Humanos , Persona de Mediana Edad , República de Corea
16.
Hernia ; 25(3): 755-764, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-32495055

RESUMEN

PURPOSE: rTAPP-VHR is a novel technique which may be added to a surgeon's armamentarium. We aim to evaluate the robotic transabdominal preperitoneal ventral hernia repair (rTAPP-VHR) learning curve based on operative times while accounting for peritoneal flap integrity. METHODS: We performed a retrospective analysis of a database collected over a 7-year period. Patients with primary ventral hernias were included and a cumulative sum analysis(CUSUM) was used to create learning curves for three subsets of operative times. A risk-adjusted CUSUM (RA-CUSUM) accounted for repair quality based on peritoneal flap completeness. The flap was considered as incomplete when peritoneal gaps were unable to be closed. RESULTS: 105 patients undergoing rTAPP-VHR were included. Learning curves were created for skin-to-skin, console, and off-console times. Patients were divided into three phases. In terms of skin-to-skin times, both phase 2&3 had a mean 11 min shorter than that of phase 1 (p = 0.0498, p = 0.0245, respectively), with a steady decrease after forty-six cases. An incomplete peritoneal flap was noted in 25/36 patients in phase 1, as compared to 5/24 and 5/45 patients in phase 2&3, respectively. When risk-adjusted for peritoneal flap completeness, gradually decreasing skin-to-skin times were observed after sixty-one cases. In terms of off-console times, the mean across three phases was 14 min, with marked improvement after forty-three cases. CONCLUSIONS: Forty-six cases were needed to achieve steadily decreasing operative times. We can assume that ensuring good-quality repairs, through maintenance of peritoneal flap integrity, was gradually improved after sixty-one cases. Moreover, familiarization with port placements and robotic docking was accomplished after forty-three cases.


Asunto(s)
Hernia Inguinal , Hernia Ventral , Laparoscopía , Procedimientos Quirúrgicos Robotizados , Hernia Inguinal/cirugía , Hernia Ventral/cirugía , Herniorrafia , Humanos , Curva de Aprendizaje , Tempo Operativo , Estudios Retrospectivos , Mallas Quirúrgicas
17.
Science ; 253(5019): 560-2, 1991 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-1857986

RESUMEN

Modulation of the activity of potassium and other ion channels is an essential feature of nervous system function. The open probability of a large conductance Ca(2+)-activated K+ channel from rat brain, incorporated into planar lipid bilayers, is increased by the addition of adenosine triphosphate (ATP) to the cytoplasmic side of the channel. This modulation takes place without the addition of protein kinase, requires Mg2+, and is mimicked by an ATP analog that serves as a substrate for protein kinases but not by a nonhydrolyzable ATP analog. Addition of protein phosphatase 1 reverses the modulation by MgATP. Thus, there may be an endogenous protein kinase activity firmly associated with this K+ channel. Some ion channels may exist in a complex that contains regulatory protein kinases and phosphatases.


Asunto(s)
Encéfalo/fisiología , Calcio/farmacología , Canales de Potasio/fisiología , Proteínas Quinasas/metabolismo , Adenosina Trifosfato/farmacología , Animales , Cinética , Membrana Dobles de Lípidos , Canales de Potasio/efectos de los fármacos , Canales de Potasio/metabolismo , Ratas
18.
Br J Anaesth ; 100(1): 50-4, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17982167

RESUMEN

BACKGROUND: Endoscopic sinus surgery (ESS) is often affected by intra-nasal bleeding, which can be influenced by various anaesthetics and preoperative conditions. This study compared the surgical condition and the amount of intra-nasal bleeding between patients given sevoflurane/remifentanil (SR) and propofol/remifentanil (PR) anaesthesia. METHODS: ASA I or II patients undergoing ESS were randomly assigned to group SR (n=20) or group PR (n=20). The extent of the preoperative surgical lesion was classified as high (> 12) and low Lund-Mackay (LM) (< or = 12) scores according to the computed tomography findings. The amount of intraoperative blood loss was calculated from the patients' haemoglobin (Hb) and the amount of blood in the suction canister. The surgeons rated the visibility of the surgical field on a numeric rating scale (NRS). RESULTS: In the high-LM score patients, the median (1st/3rd quartiles) blood loss for the SR and PR groups was 135 (121/222) and 19 (8/71) ml h(-1), respectively (P<0.01), and the mean (SD) of NRS was 5.8 (2.3) and 2.3 (1.0), respectively (P<0.05). However, in patients with low-LM score, both blood loss and NRS scores were not different between groups SR and PR. CONCLUSIONS: In the high-LM score patients, PR anaesthesia results in less blood loss and a better surgical conditions for ESS than SR anaesthesia.


Asunto(s)
Anestésicos por Inhalación , Anestésicos Intravenosos , Éteres Metílicos , Senos Paranasales/cirugía , Propofol , Adulto , Pérdida de Sangre Quirúrgica/prevención & control , Endoscopía/efectos adversos , Endoscopía/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Senos Paranasales/diagnóstico por imagen , Piperidinas , Estudios Prospectivos , Remifentanilo , Índice de Severidad de la Enfermedad , Sevoflurano , Sinusitis/diagnóstico por imagen , Sinusitis/cirugía , Tomografía Computarizada por Rayos X
20.
Oncogene ; 25(42): 5807-22, 2006 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-16909101

RESUMEN

XIAP-associated factor 1 (XAF1) is a new candidate tumor suppressor, which has been known to exert proapoptotic effects by interfering with the caspase-inhibiting activity of XIAP. To explore the XAF1's candidacy for a suppressor in urogenital tumorigenesis, we investigated the XAF1 status in a series of cancer cell lines and primary tumors derived from the bladder, kidney and prostate. Expression of XAF1 transcript was undetectable or extremely low in 60% (3/5) of bladder, 66% (10/15) of kidney, and 100% (3/3) prostate cancer cell lines. Abnormal reduction of XAF1 was also found in 33% (18/55) of primary bladder and 40% (8/20) of primary kidney tumors, and showed a correlation with advanced stage and high grade of bladder tumor. Hypermethylation at 14 CpG sites in the 5' proximal region of the XAF1 promoter was highly prevalent in cancers versus adjacent normal or benign tissues and tightly associated with reduced gene expression. XAF1 expression enhanced the apoptotic response of tumor cells to chemotherapeutic agents, such as etoposide or 5-FU. While XAF1 expression did not influence the subcellular distribution or expression of XIAP, it elevated the protein stability of p53 and its target gene expression. Moreover, the apoptosis-sensitizing and growth suppression function of XAF1 was markedly impeded by blockade of p53 function. Collectively, our study demonstrates that epigenetic alteration of XAF1 is frequent in human urogenital cancers and may contribute to the malignant progression of tumors by rendering tumor cells a survival advantage partially through the attenuated p53 response to apoptotic stresses.


Asunto(s)
Metilación de ADN , Fosfatos de Dinucleósidos/genética , Proteínas de Neoplasias/genética , Regiones Promotoras Genéticas , Proteína p53 Supresora de Tumor/genética , Neoplasias Urogenitales/genética , Proteínas Adaptadoras Transductoras de Señales , Proteínas Reguladoras de la Apoptosis , Regulación Enzimológica de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Humanos , Péptidos y Proteínas de Señalización Intracelular , Neoplasias Renales/enzimología , Neoplasias Renales/genética , Masculino , Neoplasias de la Próstata/enzimología , Neoplasias de la Próstata/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Neoplasias de la Vejiga Urinaria/enzimología , Neoplasias de la Vejiga Urinaria/genética , Neoplasias Urogenitales/enzimología
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