RESUMEN
Di-(2-ethylhexyl) phthalate (DEHP) is a widely used environmental endocrine disruptor. Many studies have reported that DEHP exposure causes reproductive toxicity and cells apoptosis. However, the mechanism by which DEHP exposure causes male reproductive toxicity remains unknown. This study investigated the role of the testicular orphan nuclear receptor4 (TR4)/Bcl-2 pathway in apoptosis induced by DEHP, which resulted in reproductive damage. To elucidate the mechanism underpinning the male reproductive toxicity of DEHP, we sought to investigate apoptotic effects, expression levels of TR4/Bcl-2 pathway in GC-2spd cells, including TR4, Bcl-2 and caspase-3. GC-2spd cells were exposed to various concentrations of DEHP (0, 50, 100, or 200µM). The results indicated that, with the increase of the concentrations of DEHP, the survival rate of cell decreased gradually. DEHP exposure at over 100µM significantly induced apoptotic cell death. DEHP decreased SOD and GSH-Px activity in 200µM group. Compared to the control group, the mRNA levels of caspase-3 increased significantly, however, Bcl-2 mRNA decreased (P<0.05). In addition, there was a significant reduction in TR4, Bcl-2 and procaspase-3 protein levels. Taken together, these results lead us to speculate that in vitro exposure to DEHP might induce apoptosis in GC-2spd cells through the TR4/Bcl-2 pathway.
Asunto(s)
Apoptosis/efectos de los fármacos , Dietilhexil Ftalato/toxicidad , Disruptores Endocrinos/toxicidad , Miembro 2 del Grupo C de la Subfamilia 2 de Receptores Nucleares/metabolismo , Plastificantes/toxicidad , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Animales , Apoptosis/fisiología , Caspasa 3/genética , Caspasa 3/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Glutatión Peroxidasa/metabolismo , Malondialdehído/metabolismo , Ratones , Proteínas Proto-Oncogénicas c-bcl-2/genética , ARN Mensajero/metabolismo , Superóxido Dismutasa/metabolismoRESUMEN
BACKGROUND: It is well known that a significant number of prostate cancers (PCa) showed different extents of radio-resistance and the tumor may recur after treatment. Recent studies demonstrated that Testicular orphan nuclear receptor 4 (TR4) could play a critical role in anti-oxidative stress responses and might modulate the DNA damage repair. The objective of this study is to investigate the role of TR4 in the radiotherapy for PCa. METHODS: The TR4 expression in tissue samples from PCa patients treated with brachytherapy was measured by immunohistochemistry (IHC). Cell survival test and colony formation assay were applied to test the radio-sensitivity of PCa cells with modulated TR4 gene expression upon irradiation. RESULTS: PCa patients with biochemical recurrence (BCR) after brachytherapy tend to have higher TR4 expression (80%, n = 30) as compared to those without BCR (36.67%, n = 30). Survival analysis demonstrated a significant higher BCR occurrence in patients with high level of TR4 expression (HR = 3.474, 95%CI 1.678-7.192, P = 0.0008). Multivariate analysis showed that the TR4 staining score on IHC was the only significant variable for predicting the PCa patients' clinical outcomes after radiotherapy (OR = 9.919, 95% CI 2.516-39.101, P = 0.001). Using cell survival test and colony forming assay, we found that the addition of functional TR4 in PC3 cells lead to elevated radio-resistance. In contrast, knocking-down TR4 in LNCaP cells resulted in increased radio-sensitivity. The γH2AX foci kinetic analysis suggested that knocking down TR4 might delay the PCa cell's DNA damage repair which would enhance the radio-sensitivity. CONCLUSION: TR4 could mediate the PCa cells' radio-sensitivity and might become a prognostic indicator for PCa patients received radiotherapy. This study provides a novel approach to manipulate radio-sensitivity of PCa cells, and may bring a promoted therapeutic outcome of radiotherapy to battle PCa in future.
Asunto(s)
Biomarcadores de Tumor/biosíntesis , Proteínas Nucleares/biosíntesis , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/radioterapia , Tolerancia a Radiación/fisiología , Proteínas Represoras/biosíntesis , Anciano , Línea Celular Tumoral , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
We show that testicular orphan nuclear receptor 4 (TR4) increases the expression of pyruvate carboxylase (PC) gene in 3T3-L1 adipocytes by direct binding to a TR4 responsive element in the murine PC promoter. While TR4 overexpression increased PC activity, oxaloacetate (OAA) and glycerol levels with enhanced incorporation of (14)C from (14)C-pyruvate into fatty acids in 3T3-L1 adipocytes, PC knockdown by short interfering RNA (siRNA) or inhibition of PC activity by phenylacetic acid (PAA) abolished TR4-enhanced fatty acid synthesis. Moreover, TR4 microRNA reduced PC expression with decreased fatty acid synthesis in 3T3-L1 adipocytes, suggesting that TR4-mediated enhancement of fatty acid synthesis in adipocytes requires increased expression of PC gene.
Asunto(s)
Adipocitos/metabolismo , Ácidos Grasos/biosíntesis , Regulación Enzimológica de la Expresión Génica , Piruvato Carboxilasa/genética , Receptores de Esteroides/metabolismo , Receptores de Hormona Tiroidea/metabolismo , Células 3T3-L1 , Animales , Técnicas de Silenciamiento del Gen , Lipogénesis , Ratones , Regiones Promotoras Genéticas/genética , Receptores de Esteroides/deficiencia , Receptores de Esteroides/genética , Receptores de Hormona Tiroidea/deficiencia , Receptores de Hormona Tiroidea/genéticaRESUMEN
While considerable effort has been made to investigate the neural mechanisms of pain, much less effort has been devoted to itch, at least until recently. However, itch is now gaining increasing recognition as a widespread and costly medical and socioeconomic issue. This is accompanied by increasing interest in the underlying neural mechanisms of itch, which has become a vibrant and rapidly-advancing field of research. The goal of the present forefront review is to describe the recent progress that has been made in our understanding of itch mechanisms.
Asunto(s)
Prurito/fisiopatología , Analgésicos Opioides/farmacología , Animales , Modelos Animales de Enfermedad , Fenómenos Electrofisiológicos/efectos de los fármacos , Fenómenos Electrofisiológicos/fisiología , Humanos , Interneuronas/fisiología , Neuronas Aferentes/efectos de los fármacos , Neuronas Aferentes/fisiología , Neurotransmisores/fisiología , Prurito/inducido químicamente , Transducción de Señal/efectos de los fármacos , Médula Espinal/efectos de los fármacos , Médula Espinal/fisiología , Nervio Trigémino/fisiopatologíaRESUMEN
Prostate cancer (PCa) stem/progenitor cells are known to have higher chemoresistance than non-stem/progenitor cells, but the underlying molecular mechanism remains unclear. We found the expression of testicular nuclear receptor 4 (TR4) is significantly higher in PCa CD133(+) stem/progenitor cells compared with CD133(-) non-stem/progenitor cells. Knockdown of TR4 levels in the established PCa stem/progenitor cells and the CD133(+) population of the C4-2 PCa cell line with lentiviral TR4 siRNA led to increased drug sensitivity to the two commonly used chemotherapeutic drugs, docetaxel and etoposide, judging from significantly reduced IC50 values and increased apoptosis in the TR4 knockdown cells. Mechanism dissection studies found that suppression of TR4 in these stem/progenitor cells led to down-regulation of Oct4 expression, which, in turn, down-regulated the IL-1 receptor antagonist (IL1Ra) expression. Neutralization experiments via adding these molecules into the TR4 knockdown PCa stem/progenitor cells reversed the chemoresistance, suggesting that the TR4-Oct4-IL1Ra axis may play a critical role in the development of chemoresistance in the PCa stem/progenitor cells. Together, these studies suggest that targeting TR4 may alter chemoresistance of PCa stem/progenitor cells, and this finding provides the possibility of targeting TR4 as a new and better approach to overcome the chemoresistance problem in PCa therapeutics.