RESUMEN
Delayed radiation myelopathy is a rare, but significant late side effect from radiation therapy that can lead to paralysis. The cellular and molecular mechanisms leading to delayed radiation myelopathy are not completely understood but may be a consequence of damage to oligodendrocyte progenitor cells and vascular endothelial cells. Here, we aimed to determine the contribution of endothelial cell damage to the development of radiation-induced spinal cord injury using a genetically defined mouse model in which endothelial cells are sensitized to radiation due to loss of the tumor suppressor p53. Tie2Cre; p53FL/+ and Tie2Cre; p53FL/- mice, which lack one and both alleles of p53 in endothelial cells, respectively, were treated with focal irradiation that specifically targeted the lumbosacral region of the spinal cord. The development of hindlimb paralysis was followed for up to 18 weeks after either a 26.7 Gy or 28.4 Gy dose of radiation. During 18 weeks of follow-up, 83% and 100% of Tie2Cre; p53FL/- mice developed hindlimb paralysis after 26.7 and 28.4 Gy, respectively. In contrast, during this period only 8% of Tie2Cre; p53FL/+ mice exhibited paralysis after 28.4 Gy. In addition, 8 weeks after 28.4 Gy the irradiated spinal cord from Tie2Cre; p53FL/- mice showed a significantly higher fractional area positive for the neurological injury marker glial fibrillary acidic protein (GFAP) compared with the irradiated spinal cord from Tie2Cre; p53FL/+ mice. Together, our findings show that deletion of p53 in endothelial cells sensitizes mice to the development of delayed radiation myelopathy indicating that endothelial cells are a critical cellular target of radiation that regulates myelopathy.
Asunto(s)
Traumatismos de la Médula Espinal/radioterapia , Animales , Relación Dosis-Respuesta en la Radiación , Células Endoteliales , Femenino , Proteína Ácida Fibrilar de la Glía/efectos de la radiación , Humanos , Masculino , Ratones , Traumatismos Experimentales por Radiación , Radiación Ionizante , Médula Espinal/efectos de los fármacos , Factores de Tiempo , Proteína p53 Supresora de Tumor/efectos de la radiaciónRESUMEN
Radiation sensitivity varies greatly between tissues. The transcription factor p53 mediates the response to radiation; however, the abundance of p53 protein does not correlate well with the extent of radiosensitivity across tissues. Given recent studies showing that the temporal dynamics of p53 influence the fate of cultured cells in response to irradiation, we set out to determine the dynamic behavior of p53 and its impact on radiation sensitivity in vivo. We find that radiosensitive tissues show prolonged p53 signaling after radiation, while more resistant tissues show transient p53 activation. Sustaining p53 using a small molecule (NMI801) that inhibits Mdm2, a negative regulator of p53, reduced viability in cell culture and suppressed tumor growth. Our work proposes a mechanism for the control of radiation sensitivity and suggests tools to alter the dynamics of p53 to enhance tumor clearance. Similar approaches can be used to enhance killing of cancer cells or reduce toxicity in normal tissues following genotoxic therapies.
Asunto(s)
Tolerancia a Radiación , Proteína p53 Supresora de Tumor/metabolismo , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Humanos , Ratones , Neoplasias/tratamiento farmacológico , Neoplasias/radioterapia , Unión Proteica/efectos de los fármacos , Proteínas Proto-Oncogénicas c-mdm2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Tolerancia a Radiación/efectos de los fármacos , Distribución Tisular/efectos de los fármacos , Carga Tumoral/efectos de los fármacos , Proteína p53 Supresora de Tumor/efectos de la radiación , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Background and objectives: The light-curing unit is considered an essential piece of equipment in every dental office. This study was conducted to evaluate the effect of Light-Emitting Diodes (LEDs) by the light cure (LC) device on gingival tissues of albino rats histologically and by regarding the expression of P53 and epidermal growth factor receptor (EGFR). Materials and methods: Gingival tissues of the rats were exposed to LEDs for 30 s with an interval of 30 s for periods of 2 and 5 min and were examined after two and four weeks of light exposure. After the set time, histological sections were studied and the P53 and EGFR expressions were evaluated immunohistochemically and by molecular methods. Results: Mild hyperplasia and mild inflammatory response were detected in higher rates after two weeks of exposure when compared to 4 weeks postexposure. Whereas fibrosis was found at a higher rate after four weeks than that found after two weeks postexposure, parakeratosis was seen only in the group that was exposed for 5 min to LC and when biopsies were taken after 2 weeks. We found that the immunohistochemical expression of P53 was not changed. Similarly, the alteration of EGFR expression was statistically nonsignificant (p > 0.05) when compared to the control group. The data obtained from the qRT-PCR reaction was analyzed using the comparative CT (2-ΔΔCT) method. Statistically, there was no significant difference in the expression of EGER and P53 gene transcripts. Conclusions: LED causes no serious alteration in P53 and EGFR expression, and only trivial histopathological changes occurred, most of which recovered after a 4-week interval.
Asunto(s)
Luces de Curación Dental , Encía/efectos de la radiación , Proteína p53 Supresora de Tumor/efectos de la radiación , Animales , Receptores ErbB/genética , Receptores ErbB/efectos de la radiación , Modelos Animales , Ratas , Proteína p53 Supresora de Tumor/genéticaRESUMEN
As a key regulator of DNA translesion synthesis (TLS) pathway, RAD18 is reported to be abnormally expressed in many kinds of cancers. In glioma, RAD18 was overexpressed in the primary and recurrent glioblastoma multiforme specimens, and its overexpression weakened ionizing radiation-induced apoptosis in glioma A172 cells. Moreover, A172 cells with mutational P53 also showed enhanced radiation resistance. And RAD18 activation induced by cyclin-dependent kinase 2 (CDK2) was repressed by P53. However, whether P53 involves in RAD18-induced radiation resistance remains unknown. Therefore, this study was conducted to explore the effects and mechanism of RAD18 in the radiation resistance of glioma and study P53 role in this process. Results showed that, RAD18 expression was obviously elevated in glioma tissues and cell lines such as U251, SHG-44, A172, U-87 MG and U-118 MG as compared with the normal brain tissues and neuroglia cells. Up-regulation of RAD18 in U-118 MG and A172 cells with lentivirus infection significantly increased cell growth and inhibited cell apoptosis, determined by CCK-8 and flow cytometry technologies. Besides, RAD18 overexpression enhanced cell growth and inhibited cell apoptosis after U-118 MG or A172 cells were irradiated at a dose of 4 Gy. On the contrary, silencing of endogenous RAD18 sensitized U-118 MG and A172 cells to radiation. Moreover, RAD18 and P53 proteins were co-located in the nucleus, and up-regulation of RAD18 decreased the expression of P53 protein and facilitated its nuclear export. Furthermore, cell growth promotion and cell apoptosis inhibition induced by RAD18 up-regulation were impaired when P53 expression was up-regulated under radiation condition. In a word, this study clarifies that RAD18 functions as a promoter in glioma progression and reduces glioma cells' sensibility to radiation through down-regulating P53, which provides new strategies to overcome the radiation resistance in glioma.
Asunto(s)
Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/radioterapia , Proteínas de Unión al ADN/biosíntesis , Glioma/metabolismo , Glioma/radioterapia , Proteína p53 Supresora de Tumor/metabolismo , Ubiquitina-Proteína Ligasas/biosíntesis , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/efectos de la radiación , Regulación hacia Abajo/fisiología , Regulación hacia Abajo/efectos de la radiación , Regulación Neoplásica de la Expresión Génica/efectos de la radiación , Humanos , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/efectos de la radiación , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/efectos de la radiaciónRESUMEN
Abnormally high production of melanin or melanogenesis in skin melanocytes results in hyperpigmentation disorders, such as melasma, senile lentigines or freckles. These hyperpigmentary skin disorders can significantly impact an individual's appearance, and may cause emotional and psychological distress and reduced quality of life. A large number of melanogenesis inhibitors have been developed, but most have unwanted side-effects. Further research is needed to better understand the mechanisms of hyperpigmentary skin disorders and to develop potent and safe inhibitors of melanogenesis. This review summarizes the current understanding of melanogenesis regulatory pathways, the potential involvement of the immune system, various drugs in current use, and emerging treatment strategies to suppress melanogenesis.
Asunto(s)
Hiperpigmentación/tratamiento farmacológico , Hiperpigmentación/metabolismo , Melaninas/biosíntesis , Factor de Transcripción Asociado a Microftalmía/antagonistas & inhibidores , Biosíntesis de Proteínas/efectos de los fármacos , Regulación hacia Abajo , Humanos , Hiperpigmentación/inmunología , Sistema de Señalización de MAP Quinasas , Factor de Transcripción Asociado a Microftalmía/metabolismo , Monofenol Monooxigenasa/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/farmacología , Azúcares/metabolismo , Azúcares/farmacología , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/efectos de la radiación , Rayos UltravioletaRESUMEN
Absorption of solar ultraviolet (UV) radiation by DNA leads to the formation of the highly mutagenic cyclobutane pyrimidine dimer (CPD). The mutagenicity of CPD is caused, in part, by the fact that their recognition and repair by the nucleotide excision repair (NER) pathway is challenging and slow. It has been previously shown that a pre-stimulation with genotoxic agents improve NER efficiency of CPD, indicating a potential adaptive response of this repair pathway. We have pre-treated human dermal fibroblasts with repeated subletal low doses of UVB (chronic low-dose of UVB; CLUV) to determine whether it could enhance NER capacity to repair CPD. Our results show that CLUV pre-treatment greatly enhances CPD repair but have little effect on the repair of another UV-induced bypirimidine photoproduct, the pyrimidine (6-4) pyrimidone photoproducts (6-4 PP). We have determined that the CLUV treatment activates p53 and we found an increase of DDB2 and XPC gene expression. This is consistent with an increasing level of NER recognition proteins, DDB2 and XPC, we found concentrated at the chromatin. This study represents the first demonstration that chronic UVB exposure can stimulate NER pathway. Altogether, these results shed light on the potential adaptability of the NER by chronic UVB irradiation and the mechanisms involved.
Asunto(s)
Adaptación Fisiológica , Aductos de ADN/metabolismo , Reparación del ADN/fisiología , Proteínas de Unión al ADN/genética , Dímeros de Pirimidina/metabolismo , ADN/efectos de la radiación , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/efectos de la radiación , Fibroblastos/metabolismo , Fibroblastos/fisiología , Fibroblastos/efectos de la radiación , Regulación de la Expresión Génica , Humanos , Transducción de Señal/efectos de la radiación , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/fisiología , Proteína p53 Supresora de Tumor/efectos de la radiación , Rayos UltravioletaRESUMEN
Despite current risk stratification systems using traditional clinicopathologic factors, many localized and locally advanced prostate cancers fail radical treatment (ie, radical prostatectomy, radiation therapy with or without androgen deprivation therapy). Therefore, a pressing need exists for enhanced methods of disease stratification through novel prognostic and predictive tools that can reliably be applied in clinical practice. Exosomes are 50- to 150-nm small vesicles released by cancer cells that reflect the genetic and nongenetic materials of parent cancer cells. Cancer cells can contain distinct sets of microRNA profiles, the expression of which can change owing to stress such as radiation therapy. These alterations or distinctions in contents allow exosomes to be used as prognostic and/or predictive biomarkers and to monitor the treatment response. Additionally, microRNAs have been shown to influence multiple processes in prostate tumorigenesis, including cell proliferation, induction of apoptosis, migration, oncogene inhibition, and radioresistance. Thus, comparative exosomal microRNA profiling at different levels could help portray tumor aggressiveness and response to radiation therapy. Although technical challenges persist in exosome isolation and characterization, recent improvements in microRNA profiling have evolved toward in-depth analyses of the exosomal cargo and its functions. We have reviewed the role of exosomes and exosomal microRNAs in biologic processes of prostate cancer progression and radiation therapy response, with a particular focus on the development of clinical assays for treatment personalization.
Asunto(s)
Exosomas/fisiología , MicroARNs/fisiología , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/radioterapia , Tolerancia a Radiación/fisiología , Senescencia Celular , Progresión de la Enfermedad , Exosomas/genética , Humanos , Masculino , MicroARNs/análisis , Fosfohidrolasa PTEN/metabolismo , Pronóstico , Neoplasias de la Próstata/mortalidad , Neoplasias de la Próstata/patología , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/efectos de la radiaciónRESUMEN
The review is devoted to an actual problem of cosmetics in gerontology, one of molecular aspects of skin aging. Cell renewal processes slow down with aging, and the proliferation apoptosis ratio shifts towards cell death. One of the most pivotal apoptotic markers is the transcription factor p53. p53 protein expression in the skin keratinocytes increases under the influence of ultraviolet radiation. Wherein when exposed to ultraviolet radiation mutant forms of p53 have been revealed in 70 % of keratinocytes. On the one hand, suppression of p53 expression decreases apoptosis in skin cells that slows down the process of aging. On the other hand, it promotes the development of tumors in the skin. Thus, maintaining the physiological balance of p53 expression in skin cells is important for the basic and practical cosmetic medicine in gerontology. In addition, p53 protein may be used as a functionality marker of skin cells when administered with geroprotective cosmetic means and instrumental cosmetology methods.
Asunto(s)
Queratinocitos/metabolismo , Envejecimiento de la Piel/fisiología , Factores de Transcripción/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Apoptosis/fisiología , Muerte Celular/fisiología , Humanos , Neoplasias Cutáneas/etiología , Factores de Transcripción/efectos de la radiación , Proteína p53 Supresora de Tumor/efectos de la radiación , Rayos UltravioletaRESUMEN
PDRG1, is short for P53 and DNA damage-regulated gene, which have been found over 10 years. Although severe studies have described the roles of PDRG1 separately in many kinds of tumors, how to act as an oncogene are unclear. To better verify the function of PDRG1 in lung cancer, both loss-function and gain-function of PDRG1 studies based on two human lung cancer lines were performed. Following the transfection of PDRG1, both A549 and 95-D cells showed significant changes in cell viability, the expression of some protein and apoptosis, which were all implied the PDRG1 is an oncogene. Another interesting finding is PDRG1 could promote radioresistance involved the ATM-p53 signaling pathway in lung cancer. If we combine radiotherapy with gene-targeted therapy together effectively, predominant effect may be acquired, which is a huge milestone in clinical cure about lung cancer.
Asunto(s)
Proteínas de la Ataxia Telangiectasia Mutada/genética , Proteínas de Unión al ADN/genética , Neoplasias Pulmonares/genética , Oncogenes/genética , Tolerancia a Radiación/genética , Proteína p53 Supresora de Tumor/genética , Animales , Proteínas de la Ataxia Telangiectasia Mutada/efectos de la radiación , Línea Celular Tumoral , Supervivencia Celular/genética , Supervivencia Celular/efectos de la radiación , Proteínas de Unión al ADN/administración & dosificación , Proteínas de Unión al ADN/efectos de la radiación , Humanos , Neoplasias Pulmonares/radioterapia , Ratones , Ratones Desnudos , Oncogenes/efectos de la radiación , Transducción de Señal/genética , Transducción de Señal/efectos de la radiación , Proteína p53 Supresora de Tumor/efectos de la radiaciónRESUMEN
Objetivos. Analizar qué factores valorados en resonancia magnética (RM) y anatomopatológicos de los tumores triple negativo (TN) se relacionan con la recidiva tumoral y con una menor supervivencia libre de enfermedad. Valorar la supervivencia y las recidivas en función de la presencia de componente in situ (CIS). Material y métodos. Estudio retrospectivo de las RM realizadas desde 2007 a 2014, con inclusión de 122 mujeres con cáncer de mama TN y RM de estadificación. En RM se valoraron las características morfológicas (tamaño, márgenes, morfología y señal interna en secuencia T2) y dinámicas (perfusión y difusión). Se estudiaron también los factores anatomopatológicos (Ki67, p53, CK5/6, grado nuclear y Scarff-Bloom) y se analizó la presencia de CIS y el grado tumoral (alto o no alto grado). Se compararon las distintas variables con la presencia de recidiva y se realizó estudio de supervivencia. Resultados. El realce no nodular presentó mayor porcentaje en el grupo de recidivas, y la diferencia fue estadísticamente significativa (p=0,038) y se relacionó con una menor supervivencia libre de enfermedad (p=0,023). La restricción a la difusión (p=0,079) y el ki67 (p=0,052) no asociaron un peor pronóstico. Se detectó CIS en el 44% de los TN, con mayor proporción en el grupo de recidiva, sin relación con una menor supervivencia (p = 0,185). Conclusión. El realce no nodular demostró ser un factor de peor pronóstico. La restricción a la difusión, el ki67 y la presencia de CIS no se asociaron a una menor supervivencia libre de enfermedad (AU)
Objectives. To analyze what factors in magnetic resonance imaging (MRI) and histological study of triple-negative breast cancers are related to tumor recurrence and to shorter disease-free survival. To analyze survival and recurrence in function of the presence of an in situ component. Material and methods. This was a retrospective study of MRI staging examinations in 122 women with triple-negative breast cancer done from 2007 through 2014. In the MRI, we evaluated morphological variables (size, margins, morphology, internal signal in T2-weighted sequences) and dynamic variables (perfusion and diffusion). In the histological study, we evaluated Ki67, p53, CK5/6, nuclear grade, and Scarff-Bloom grade, as well as the presence of an in situ component and tumor grade (high grade or not high grade). We compared the variables between patients with tumor recurrence and those without, and we conducted a survival analysis. Results. Non-nodular enhancement was more common in patients with tumor recurrence (p=0.038) and was associated with shorter disease-free survival (p=0.023). Neither diffusion restriction (p=0.079) nor ki67 (p=0.052) was associated with a worse prognosis. An in situ component was detected in 44% of triple-negative tumors, and a greater proportion of patients in the group with tumor recurrence had an in situ component; however, the presence of an in situ component was not associated with shorter survival (p = 0.185). Conclusion. Non-nodular enhancement was associated with a worse prognosis. Diffusion restriction, ki67, and the presence of an in situ component were not associated with shorter disease-free survival (AU)
Asunto(s)
Humanos , Femenino , Neoplasias de la Mama/patología , Neoplasias de la Mama , Neoplasias de la Mama Triple Negativas/patología , Neoplasias de la Mama Triple Negativas , Pronóstico , Carcinoma in Situ/patología , Carcinoma in Situ , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética/métodos , Estudios Retrospectivos , Perfusión/métodos , Antígeno Ki-67/análisis , Antígeno Ki-67/efectos de la radiación , Proteína p53 Supresora de Tumor/análisis , Proteína p53 Supresora de Tumor/efectos de la radiación , Inmunohistoquímica/métodosRESUMEN
High-risk human papillomaviruses (HR-HPVs) are the causative agents of cervical cancer, and they are also associated with a subset of head and neck squamous cell carcinomas. In addition, HPVs have also been postulated in the development of non-melanoma skin cancers (NMSC). In these cancers, the oncogene E6 is best known for its ability to inactivate the tumor suppressor p53 protein. Interestingly, in transgenic mice for HPV16 E6 (K14E6), it was reported that E6 alone induced epithelial hyperplasia and delay in differentiation in skin epidermis independently of p53 inactivation. Transforming growth factor ß (TGFß) is an important regulator of cell growth/differentiation and apoptosis, and this pathway is often lost during tumorigenesis. Ultraviolet radiation B (UVB) exposure activates diverse cellular responses, including DNA damage and apoptosis. In this study, we investigated whether the E6 oncogene alone or in combination with UVB dysregulate some components of the TGFß pathway in the epidermis of K14E6 mice. We used 8-day-old K14E6 and non-transgenic mice irradiated and unirradiated with a single dose of UVB. We found that the E6 oncogene and UVB irradiation impair the TGFß pathway in epidermis of K14E6 mice by downregulation of the TGFß type II receptor (TßRII). This loss of TßRII prevents downstream activation of Smad2 and target genes as p15, an important regulator of cell cycle progression. In summary, the TGFß signalling in cells of the epidermis is downregulated in our mouse model by both the E6 oncoprotein and the UVB irradiation.
Asunto(s)
Epidermis/efectos de la radiación , Proteínas Oncogénicas Virales/genética , Proteínas Represoras/genética , Transducción de Señal/genética , Transducción de Señal/efectos de la radiación , Factor de Crecimiento Transformador beta/genética , Factor de Crecimiento Transformador beta/efectos de la radiación , Rayos Ultravioleta , Animales , Apoptosis/efectos de la radiación , Daño del ADN/efectos de la radiación , Modelos Animales de Enfermedad , Relación Dosis-Respuesta en la Radiación , Regulación hacia Abajo/genética , Regulación hacia Abajo/efectos de la radiación , Epidermis/metabolismo , Epidermis/patología , Ratones , Ratones Transgénicos , Proteínas Oncogénicas Virales/metabolismo , Fosforilación , Proteínas Represoras/metabolismo , Proteína Smad2 , Factor de Crecimiento Transformador beta/metabolismo , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/efectos de la radiaciónRESUMEN
Breast cancer is the second leading cause of cancer mortality and the most frequent cancer found in women around the globe. The development of breast cancer is a multistep and complicated process that includes the development of ductal and lobular cells into atypical hyperplasia, carcinoma in situ, and invasive carcinoma, with an ability to metastasize. The efficacy of radiotherapy in breast cancer seems to be reduced because of a frequently observed lack of cellular sensitivity to apoptosis. Both Bcl-2 and p53 are linked to apoptosis pathways and are known to play a role in the outcome of radiotherapy. Resistance of tumor cells to therapeutic drugs and the undesirable cytotoxicity of normal cells are frequently observed in treatment outcomes in clinics. Research is, therefore, needed to develop strategies for improving the protocols of chemotherapy and radiotherapy in patients with breast cancer. This review focuses on understanding the molecular mechanisms of enhanced tumor cell killing by the combined action of certain anticancer drugs together with gamma radiation in vitro, with possible implications for practical applications in clinics.
Asunto(s)
Antineoplásicos/uso terapéutico , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Neoplasias de la Mama/patología , Radiación Ionizante , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/radioterapia , Quimioterapia , Femenino , Humanos , Hiperplasia/tratamiento farmacológico , Hiperplasia/patología , Hiperplasia/radioterapia , Proteínas Proto-Oncogénicas c-bcl-2/efectos de los fármacos , Proteínas Proto-Oncogénicas c-bcl-2/efectos de la radiación , Radioterapia , Resultado del Tratamiento , Proteína p53 Supresora de Tumor/efectos de los fármacos , Proteína p53 Supresora de Tumor/efectos de la radiaciónRESUMEN
Ultraviolet (UV) radiation is considered to be essential for the progression of actinic keratosis (AK) to squamous cell carcinoma (SCC); however, the mechanisms have not been fully elucidated. To understand this process, the effects of UV radiation on the transforming growth factor beta 1 (TGFß1)/Smads pathway and p53 in normal skin and AK were studied. Normal human skin and AK tissues were cultured and divided into the following four groups according to the UV radiation dose: 0 (control group), 5, 10, and 20 J/cm2. The tissues were radiated for four consecutive days; 24 h after radiation, the tissues were collected for investigation. Compared with the control group, greater proliferative inhibition and apoptosis were induced by UV radiation in normal skin than AK. The expression of TGFß1, Smad7, and p53 was increased in AK and normal skin, while the level of TßRII was decreased. Smad2 was reduced in AK only. The expressions of TßRI, Smad3, and Smad4 were not significantly changed. The results demonstrated that although p53 was induced, suppression of the TGFß1/Smads pathway by UV radiation might contribute to the progression of AK to SCC.
Asunto(s)
Queratosis Actínica/metabolismo , Proteínas Smad/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Rayos Ultravioleta/efectos adversos , Apoptosis/efectos de la radiación , Proliferación Celular/efectos de la radiación , Células Cultivadas , Humanos , Proteínas Serina-Treonina Quinasas/biosíntesis , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/efectos de la radiación , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptor Tipo II de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/biosíntesis , Receptores de Factores de Crecimiento Transformadores beta/metabolismo , Receptores de Factores de Crecimiento Transformadores beta/efectos de la radiación , Piel/efectos de la radiación , Proteínas Smad/biosíntesis , Proteínas Smad/efectos de la radiación , Proteína Smad2/biosíntesis , Proteína Smad2/metabolismo , Proteína Smad2/efectos de la radiación , Proteína smad3/biosíntesis , Proteína smad3/metabolismo , Proteína smad3/efectos de la radiación , Proteína Smad4/biosíntesis , Proteína Smad4/metabolismo , Proteína Smad4/efectos de la radiación , Proteína smad7/biosíntesis , Proteína smad7/metabolismo , Proteína smad7/efectos de la radiación , Factor de Crecimiento Transformador beta1/biosíntesis , Factor de Crecimiento Transformador beta1/efectos de la radiación , Proteína p53 Supresora de Tumor/biosíntesis , Proteína p53 Supresora de Tumor/efectos de la radiaciónRESUMEN
Ionizing radiation, such as that emitted by uranium, may cause mutations and consequently lead to neoplasia in human cells. The TP53 gene acts to maintain genomic integrity and constitutes an important biomarker of susceptibility. The present study investigated the main alterations observed in exons 4, 5, 6, 7, and 8 of the TP53 gene and adjacent introns in Amazonian populations exposed to radioactivity. Samples were collected from 163 individuals. Occurrence of the following alterations was observed: (i) a missense exchange in exon 4 (Arg72Pro); (ii) 2 synonymous exchanges, 1 in exon 5 (His179His), and another in exon 6 (Arg213Arg); (iii) 4 intronic exchanges, 3 in intron 7 (C â T at position 13.436; C â T at position 13.491; T â G at position 13.511) and 1 in intron 8 (T â G at position 13.958). Alteration of codon 72 was found to be an important risk factor for cancer development (P = 0.024; OR = 6.48; CI: 1.29-32.64) when adjusted for age and smoking. Thus, TP53 gene may be an important biomarker for carcinogenesis susceptibility in human populations exposed to ionizing radiation.
Asunto(s)
Exones/efectos de la radiación , Inestabilidad Genómica/efectos de la radiación , Radiación Ionizante , Proteína p53 Supresora de Tumor/genética , Adulto , Alelos , Transformación Celular Neoplásica , Exposición a Riesgos Ambientales , Humanos , Persona de Mediana Edad , Mutación , Neoplasias/epidemiología , Neoplasias/genética , Neoplasias/patología , Dosis de Radiación , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/efectos de la radiación , Uranio/toxicidadRESUMEN
The tumor-suppressor gene p53 encodes a phosphoprotein involved in the control of cell growth. p53 expression and function have been documented in malignancy, apoptosis and the aging processes. Recently, p53 has been mapped and characterized in the normal cornea across different species. In the present study, high levels of cytoplasmic p53 protein were noted in normal primary corneal epithelium cultures by immunohistochemistry and western blot analysis. Following ultraviolet (UV) irradiation, the level of cytoplasmic p53 protein expression was increased beginning from 30 min and lasting until 6 h post-irradiation and then returned close to control levels by 24 h. Cytoplasmic p53 phosphorylation was detected from 30 min following UV treatment until 6 h post-irradiation. p53 protein became apparent in the nucleus in a fraction of these cultured cells beginning 30 min following UV irradiation and was still present 24 h later. We also found that p53 colocalized with mitochondria 2 h following UV irradiation in some of the cells and remained there up to 24 h. As the expression levels of p53 transcription following UV irradiation were not significantly altered, the increase in cytoplasmic p53 protein expression may be conditional only upon post-translational stabilization. We also observed that the apoptotic index increased following UV irradiation in the same time frame as the p53 nuclear transfer and was partially suppressed by pifithrin-α, which is a reversible inhibitor of p53-mediated apoptosis and p53-dependent gene transcription. The present study offers new evidence suggesting that cytoplasmic p53 in rodent corneal epithelium is functionally active.
Asunto(s)
Apoptosis/efectos de la radiación , Epitelio Corneal/efectos de la radiación , Proteína p53 Supresora de Tumor , Animales , Anticuerpos Monoclonales/inmunología , Apoptosis/efectos de los fármacos , Benzotiazoles/farmacología , Células Cultivadas , Epitelio Corneal/metabolismo , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , ARN Mensajero/análisis , Tolueno/análogos & derivados , Tolueno/farmacología , Transcripción Genética/efectos de los fármacos , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/efectos de la radiación , Rayos UltravioletaRESUMEN
PURPOSE: The aim of this study was to study the effect of ionizing radiation on apoptosis-related protein concentrations as well as the radio-protective role of Ginkgo biloba and Angelica archangelica. The experiments were performed on 68 adult Wistar rats weighing 175 g (±10 g). Animals were subdivided into control group in which the animals received neither the protector nor the isotopes. The second group represents the animals that received 1 mCi of (99m)Tc only. The third group represents the animals that received A. archangelica for 7 days. The fourth group represents the animals that received G. biloba for 7 days. The fifth group represents the animals that received 1 mCi of (99m)Tc once after receiving A. archangelica for 7 days. The sixth group represents the animals that received mCi of (99m)Tc once after receiving G. biloba for 7 days. Radiation was administered as intravenous injection by 1 mCi of (99m)Tc with the legend methoxyisobutylisonitrile for 24 h. The concentration of p53, Bcl2 and malondialdehyde in liver as well as histopathological examination of liver cells were carried out. Results showed that apoptotic to anti-apoptotic protein ratio significantly (p < 0.05) returned to its normal ratio when radioisotopic injection was administered after the protection period for a week by both A. archangelica and G. biloba in a dose based on the animal body weight. Electron microscope photographing supported this finding. CONCLUSION: It was concluded that both antioxidants can be used as radio-protective agents in cases of ionizing radiation exposure.
Asunto(s)
Hígado/efectos de los fármacos , Extractos Vegetales/farmacología , Traumatismos Experimentales por Radiación/tratamiento farmacológico , Protectores contra Radiación/farmacología , Proteína p53 Supresora de Tumor/efectos de los fármacos , Proteína bcl-X/efectos de los fármacos , Angelica archangelica/química , Animales , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Ginkgo biloba/química , Hepatocitos/efectos de los fármacos , Hepatocitos/efectos de la radiación , Hepatocitos/ultraestructura , Inyecciones Intravenosas , Hígado/metabolismo , Hígado/efectos de la radiación , Malondialdehído/metabolismo , Traumatismos Experimentales por Radiación/metabolismo , Traumatismos Experimentales por Radiación/patología , Radiofármacos/toxicidad , Ratas , Ratas Wistar , Pertecnetato de Sodio Tc 99m/toxicidad , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/efectos de la radiación , Proteína bcl-X/metabolismo , Proteína bcl-X/efectos de la radiaciónRESUMEN
The tumor suppressor protein, p53 is one of the most important cellular defences against malignant transformation. In response to cellular stressors p53 can induce apoptosis, cell cycle arrest or senescence as well as aid in DNA repair. Which p53 function is required for tumor suppression is unclear. The proline-rich domain (PRD) of p53 (residues 58-101) has been reported to be essential for the induction of apoptosis. To determine the importance of the PRD in tumor suppression in vivo we previously generated a mouse containing a 33-amino-acid deletion (residues 55-88) in p53 (mΔpro). We showed that mΔpro mice are protected from T-cell tumors but not late-onset B-cell tumors. Here, we characterize the functionality of the PRD and show that it is important for mediating the p53 response to DNA damage induced by γ-radiation, but not the p53-mediated responses to Ha-Ras expression or oxidative stress. We conclude that the PRD is important for receiving incoming activating signals. Failure of PRD mutants to respond to the activating signaling produced by DNA damage leads to impaired downstream signaling, accumulation of mutations, which potentially leads to late-onset tumors.
Asunto(s)
Dominios Proteicos Ricos en Prolina/fisiología , Radiación Ionizante , Proteína p53 Supresora de Tumor/química , Proteína p53 Supresora de Tumor/metabolismo , Animales , Linfocitos B/metabolismo , Linfocitos B/fisiología , Linfocitos B/efectos de la radiación , Transformación Celular Neoplásica/genética , Células Cultivadas , Daño del ADN/genética , Daño del ADN/efectos de la radiación , Embrión de Mamíferos , Células Madre Embrionarias/metabolismo , Células Madre Embrionarias/fisiología , Células Madre Embrionarias/efectos de la radiación , Ratones , Ratones Noqueados , Modelos Biológicos , Prolina/química , Prolina/fisiología , Dominios Proteicos Ricos en Prolina/genética , Dominios Proteicos Ricos en Prolina/efectos de la radiación , Eliminación de Secuencia/fisiología , Estrés Fisiológico/fisiología , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/efectos de la radiaciónRESUMEN
Variant alleles of the human melanocortin 1 receptor (MC1R) reduce the ability of melanocytes to produce the dark pigment eumelanin, with R alleles being most deficient. Cultured melanocytes of MC1R R/R variant genotype give reduced responses to [Nle(4), D-Phe(7)]α-melanocyte-stimulating hormone (NDP-MSH) ligand stimulation and lower levels of DNA repair than MC1R wild-type strains. p38 controls xeroderma pigmentosum (XP)-C recruitment to DNA damage sites through regulating ubiquitylation of the DNA damage-binding protein 2 (DDB2) protein, and p53 is implicated in the nuclear excision repair process through its regulation of XP-C and DDB2 protein expression. We report the effects of MC1R ligand treatment and UVR exposure on phosphorylation of p38 and p53, and DDB2 protein expression in MC1R variant strains. Wild-type MC1R melanocyte strains grown together with keratinocytes in coculture, when treated with NDP-MSH and exposed to UVR, gave synergistic activation of p38 and p53 phosphorylation, and were not replicated by R/R variant melanocytes, which have lower basal levels of phosphorylated forms of p38. Minor increases in p38 phosphorylation status in R/R variant melanocyte cocultures could be attributed to the keratinocytes alone. We also found that MC1R wild-type strains regulate DDB2 protein levels through p38, but MC1R R/R variant melanocytes do not. This work confirms the important functional role that the MC1R receptor plays in UVR stress-induced DNA repair.
Asunto(s)
Alelos , Proteínas de Unión al ADN/metabolismo , Receptor de Melanocortina Tipo 1/genética , Proteína p53 Supresora de Tumor/metabolismo , alfa-MSH/análogos & derivados , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Células Cultivadas , Técnicas de Cocultivo , Reparación del ADN/genética , Proteínas de Unión al ADN/efectos de los fármacos , Proteínas de Unión al ADN/efectos de la radiación , Humanos , Queratinocitos , Melanocitos/efectos de los fármacos , Melanocitos/efectos de la radiación , Fosforilación/efectos de los fármacos , Fosforilación/genética , Fosforilación/efectos de la radiación , Transducción de Señal , Proteína p53 Supresora de Tumor/efectos de los fármacos , Proteína p53 Supresora de Tumor/efectos de la radiación , Rayos Ultravioleta , alfa-MSH/farmacología , Proteínas Quinasas p38 Activadas por Mitógenos/efectos de los fármacos , Proteínas Quinasas p38 Activadas por Mitógenos/efectos de la radiaciónRESUMEN
Solar ultraviolet (UV) radiation is an important risk factor in skin carcinogenesis. This has been attributed mainly to the UVB waveband because the high-energetic photons are capable of interacting with DNA and inducing DNA damage. Recently, UVA light has also gained increasing interest in relation to DNA alteration. Although UVA photons are less energetic than UVB, they comprise a major fraction of sunlight UV radiation and penetrate deep into the skin. The study was carried out to compare the acute effects of UVA and UVB light on SKH-1 mice in relation to DNA damage and associated parameters. Mice were exposed to UVA (10 and 20 J/cm(2)) or UVB (200 and 800 mJ/cm(2)) radiation. The number of DNA single-strand breaks (SSB) in lymphocytes, amount of phosphorylated histone H2AX (gamma-H2AX) and apoptosis or DNA fragmentation (TUNEL-positive cells) in skin sections and level of gamma-H2AX, activated caspase-3 and phosphorylated p53 in skin were evaluated after 4 and 24 h. SSB analyzed by alkaline comet assay were found to be 4 and 24 h following UVB and UVA treatment, respectively. TUNEL and gamma-H2AX-positive cell were observed only in UVB exposed animals at both time intervals. The level of activated caspase-3 and phospho-p53 was increased 24 h after UVA and UVB radiation and was more apparent in UVB treated mice. The results indicate that the mechanism of DNA damage caused by acute UVA exposure includes formation of SSB (oxidative damage), but not double-strand breaks.
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Daño del ADN , ADN/efectos de la radiación , Piel/efectos de la radiación , Rayos Ultravioleta/efectos adversos , Animales , Apoptosis/efectos de la radiación , Caspasa 3/efectos de la radiación , Roturas del ADN de Cadena Simple , Fragmentación del ADN , Femenino , Histonas/efectos de la radiación , Ratones , Ratones Pelados , Distribución Aleatoria , Luz Solar/efectos adversos , Proteína p53 Supresora de Tumor/efectos de la radiaciónRESUMEN
Changes of DNA structural condition, the level of membrane Fas-receptor expression, caspase-3 functional activity, concentrations of Ca2+, p53 and cytochrome c proteins of human lymphocytes in dynamics of apoptosis development induced by UV-light (240-390 nm) at doses 151, 1510, 3020 J/m2 and reactive oxygen species (superoxide anion-radical, hydroxyl radicals, hydrogen peroxide, singlet oxygen) have been studied. UV-light and reactive oxygen species have been established to induce fragmentation of lymphocyte DNA after 20 h incubation of the modified cells. It has been shown, that the increase in the expression level of membrane death Fas-receptors is observed during 1-5 h after exposure oflymphocytes to UV-light and ROS compared with intact cells. Also revealed is augmentation of lymphocyte caspase-3 functional activity 4 h after generation of singlet oxygen, hydroxyl radical and hydrogen peroxide addition, as well as 8 and 24 and 6 and 8 h after UV-irradiation of the cells at doses 151 and 1510 J/m2, correspondingly. Using DNA-comet method made it possible to tape that DNA damages (single-strand breaks) appear 15-20 min after lymphocyte UV-irradiation at doses 1510 and 3020 J/m and addition of hydrogen peroxide in concentration 10(-6) mol/l (C1 type comet) and reach their maximum 6 h after modification of the cells (C2 and C3 type comets). It has been observed, that 6 h after exposure oflymphocytes to hydrogen peroxide and UV-light at doses 1510 and 3020 J/m2, the p53 level of investigated cells raises. It has also been shown that the higher level of calcium in lymphocyte cytosol in conditions of UV-light exposure (1510 J/m2) and exogenous generation of reactive oxygen species is caused by Ca2+ exit from intracellular depots as a result of activating the components of the phosphoinositide mechanism for transferring information into a cell. Ideas about correlation between alterations of the calcium level and initiation of programmed cellular destruction of human lymphocytes after exposure to UV-irradiation and ROS is proposed. The authors come to the conclusion about the leading role of receptor-mediated (Fas-dependent) caspase- and p53-dependent ways of realizing apoptosis oflymphocytes induced by UV-light at doses 151 and 1510 J/m2 and active oxygen metabolites. The pattern of the possible intracellular events leading to apoptotic destruction of lymphocytes after their UV-irradiation is offered.