RESUMO
mRNA translation is a fundamental process for life. Selection of the translation initiation site (TIS) is crucial, as it establishes the correct open reading frame for mRNA decoding. Studies in vertebrate mRNAs discovered that a purine at -3 and a G at +4 (where A of the AUG initiator codon is numbered + 1), promote TIS recognition. However, the TIS context in other eukaryotes has been poorly experimentally analyzed. We analyzed in vitro the influence of the -3, -2, -1 and + 4 positions of the TIS context in rabbit, Drosophila, wheat, and yeast. We observed that -3A conferred the best translational efficiency across these species. However, we found variability at the + 4 position for optimal translation. In addition, the Kozak motif that was defined from mammalian cells was only weakly predictive for wheat and essentially non-predictive for yeast. We discovered eight conserved sequences that significantly disfavored translation. Due to the big differences in translational efficiency observed among weak TIS context sequences, we define a novel category that we termed 'barren AUG context sequences (BACS)', which represent sequences disfavoring translation. Analysis of mRNA-ribosomal complexes structures provided insights into the function of BACS. The gene ontology of the BACS-containing mRNAs is presented.
Assuntos
Códon de Iniciação , Sequência Conservada , Biossíntese de Proteínas , Animais , Coelhos , Códon de Iniciação/genética , Mamíferos/genética , Iniciação Traducional da Cadeia Peptídica , RNA Mensageiro/metabolismo , Leveduras , Eucariotos/genética , Eucariotos/metabolismoRESUMO
Among the different types of cancer affecting the central nervous system (CNS), glioblastoma (GB) is classified by the World Health Organization (WHO) as the most common and aggressive CNS cancer in adults. GB incidence is more frequent among persons aged 45-55 years old. GB treatments are based on tumor resection, radiation, and chemotherapies. The current development of novel molecular biomarkers (MB) has led to a more accurate prediction of GB progression. Moreover, clinical, epidemiological, and experimental studies have established genetic variants consistently associated with the risk of suffering GB. However, despite the advances in these fields, the survival expectancy of GB patients is still shorter than 2 years. Thus, fundamental processes inducing tumor onset and progression remain to be elucidated. In recent years, mRNA translation has been in the spotlight, as its dysregulation is emerging as a key cause of GB. In particular, the initiation phase of translation is most involved in this process. Among the crucial events, the machinery performing this phase undergoes a reconfiguration under the hypoxic conditions in the tumor microenvironment. In addition, ribosomal proteins (RPs) have been reported to play translation-independent roles in GB development. This review focuses on the research elucidating the tight relationship between translation initiation, the translation machinery, and GB. We also summarize the state-of-the-art drugs targeting the translation machinery to improve patients' survival. Overall, the recent advances in this field are shedding new light on the dark side of translation in GB.
RESUMO
BACKGROUND: Epidemiological evidence associates chronic exposure to particulate matter (PM) with respiratory damage and lung cancer. Inhaled PM may induce systemic effects including inflammation and metastasis. This study evaluated whether PM induces expression of adhesion molecules in lung cancer cells promoting interaction with monocytes. METHODS: The expression of early and late adhesion molecules and their receptors was evaluated in A549 (human lung adenocarcinoma) cells using a wide range of concentrations of PM2.5 and PM10. Then we evaluated cellular adhesion between A549 cells and U937 (human monocytes) cells after PM exposure. RESULTS: We found higher expression of both early and late adhesion molecules and their ligands in lung adenocarcinoma cells exposed to PM2.5 and PM10 particles present in the air pollution at Mexico City from 0.03 µg/cm2 with a statistically significant difference (p ≤ 0.05). PM10 had stronger effect than PM2.5. Both PM also stimulated cellular adhesion between tumor cells and monocytes. CONCLUSIONS: This study reveals a comprehensive expression profile of adhesion molecules and their ligands upregulated by PM2.5 and PM10 in A549 cells. Additionally these particles induced cellular adhesion of lung cancer cells to monocytes. This highlights possible implications of PM in two cancer hallmarks i.e. inflammation and metastasis, underlying the high cancer mortality associated with air pollution.
Assuntos
Adenocarcinoma de Pulmão , Poluentes Atmosféricos , Poluição do Ar , Neoplasias Pulmonares , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Poluição do Ar/análise , Linhagem Celular , Cidades , Humanos , México , Material Particulado/análise , Material Particulado/toxicidadeRESUMO
Lung cancer (LC) is the first cause of cancer-related deaths worldwide. Elucidating the pathogenesis of LC will give information on key elements of tumor initiation and development while helping to design novel targeted therapies. LC is an heterogeneous disease that has the second highest mutation rate surpassed only by melanoma, since 90% of LC occurs in tobacco smokers. However, only a small percent of smokers develops LC, indicating an inherent genomic instability. Additionally, LC in never smokers suggests other molecular mechanisms not causally linked to tobacco carcinogens. This review presents a current outlook of the connection between LC and genomic instability at the molecular and clinical level summarizing its implications for diagnosis, therapy, and prognosis. The genomic landscape of LC shows widespread alterations such as DNA methylation, point mutations, copy number variation, chromosomal translocations, and aneuploidy. Genome maintenance mechanisms including cell cycle control, DNA repair, and mitotic checkpoints open a window to translational research for finding novel diagnostic biomarkers and targeted therapies in LC.
RESUMO
Adenocarcinomas of the ampulla of Vater account for 0.5% of malignant neoplasms of the gastrointestinal tract and 6% to 20% of malignant periampullary neoplasms, with most patients being candidates for elective surgery. Our objective was to evaluate the clinicopathological prognostic factors of ampullary adenocarcinomas after surgical resection in a Mexican population. From the records of the Department of Pathology at the Instituto Nacional de Cancerología, México, cases diagnosed as adenocarcinomas of the ampulla of Vater were selected over a period of 11 years, from January 2005 to September 2015. Cases with a pancreaticoduodenectomy report were included, and from each case, demographic and pathological data of the surgical specimen were obtained. Univariate and multivariate statistical analyses were performed using the log-rank test and Cox regression. Of 157 cases diagnosed as ampullary adenocarcinomas, 104 patients were excluded as not eligible for surgical treatment at the time of diagnosis. In the remaining 53 patients, a pancreaticoduodenectomy was performed. The mean age of the entire group was 55.4 years, and most were men. Intestinal-type adenocarcinomas were more frequent (77.4%) than pancreatobiliary-type (15.1%), with most being without perineural invasion, well to moderately differentiated, and less than 3 cm in size. Lymph node metastasis and age greater than 65 years had a negative impact on overall survival of the patients. The most convenient classification of malignant epithelial tumors of the Vaterian system is according to the histopathologic phenotype grouped into intestinal-, pancreatobiliary-, and mixed-type adenocarcinomas, as well as uncommon variants.
Assuntos
Adenocarcinoma/patologia , Carcinoma Ductal Pancreático/patologia , Neoplasias do Ducto Colédoco/patologia , Neoplasias Duodenais/patologia , Adenocarcinoma/mortalidade , Adulto , Idoso , Ampola Hepatopancreática/patologia , Carcinoma Ductal Pancreático/mortalidade , Neoplasias do Ducto Colédoco/mortalidade , Estudos Transversais , Neoplasias Duodenais/mortalidade , Feminino , Humanos , Masculino , México , Pessoa de Meia-Idade , PrognósticoRESUMO
Exposure to urban particulate matter (PM) is correlated with increases in the emergence of health services due to adverse events and deaths and is mainly related to cardiorespiratory complications. The translocation of particles from the lung into circulation has been proposed as a factor that may trigger systemic effects. Monocytes may be exposed to PM, and if the monocytes are activated, then they are likely to adhere to endothelial cells in a distant organ due to the expression of receptors for adhesion molecules. In the present study, we evaluated the expression of receptors for adhesion molecules (sLex, PSGL-1, LFA-1, VLA-4 and αVß3) in monocytes (U937 cells) exposed for 3 or 18â¯h to PM10 (0.001, 0.003, 0.010, 0.030, 0.300, 3 or 30⯵g/mL). Exposed cells were co-cultured with human endothelial cells that were naive or previously exposed to the same particles. When U937 cells were exposed to PM10, similar levels of expression for early and late receptors for adhesion molecules were observed from 30â¯ng/mL as those induced by TNF-α. Cells exposed to particles at concentrations above 30â¯ng/mL were more adhesive to naive or exposed human endothelial cells. Taken together, our results suggest that it is plausible that activated monocytes may play a role in systemic effects induced by PM10 due to the size distribution of the particles and the concentrations required to trigger the expression of receptors for adhesion molecules in monocytes.
Assuntos
Moléculas de Adesão Celular/metabolismo , Monócitos/metabolismo , Material Particulado/farmacologia , Células Endoteliais/metabolismo , Humanos , Células U937RESUMO
Curcumin has protective effects against toxic agents and shows preventive properties for various diseases. Particulate material with an aerodynamic diameter of ≤10 µm (PM10) and titanium dioxide nanoparticles (TiO2-NPs) induce endothelial dysfunction and activation. We explored whether curcumin is able to attenuate different events related to endothelial activation. This includes adhesion, expression of adhesion molecules and oxidative stress induced by PM10 and TiO2-NPs. Human umbilical vein endothelial cells (HUVEC) were treated with 1, 10 and 100 µM curcumin for 1 h and then exposed to PM10 at 3 µg/cm2 or TiO2-NPs at 10 µg/cm2. Cell adhesion was evaluated by co-culture with U937 human myelomonocytic cells. Adhesion molecules expression was measured by flow cytometry after 3 or 24 h of exposure. Oxidative stress was determined by 2,7-dichlorodihydrofluorescein (H2DCF) oxidation. PM10 and TiO2-NPs induced the adhesion of U937 cells and the expression of E- and P-selectins, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and platelet-endothelial cell adhesion molecule-1 (PECAM-1). The expression of E- and P-selectins matched the adhesion of monocytes to HUVEC after 3 h. In HUVEC treated with 1 or 10 µM curcumin, the expression of adhesion molecules and monocytes adhesion was significantly diminished. Curcumin also partially reduced the H2DCF oxidation induced by PM10 and TiO2-NPs. Our results suggest an anti-inflammatory and antioxidant role by curcumin attenuating the activation caused on endothelial cells by exposure to particles. Therefore, curcumin could be useful in the treatment of diseases where an inflammatory process and endothelial activation are involved.
Assuntos
Antioxidantes/farmacologia , Curcumina/farmacologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Nanopartículas/toxicidade , Material Particulado/antagonistas & inibidores , Biomarcadores/metabolismo , Adesão Celular/efeitos dos fármacos , Cidades , Técnicas de Cocultura , Selectina E/genética , Selectina E/metabolismo , Fluoresceínas/química , Expressão Gênica , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Molécula 1 de Adesão Intercelular/genética , Molécula 1 de Adesão Intercelular/metabolismo , México , Estresse Oxidativo/efeitos dos fármacos , Selectina-P/genética , Selectina-P/metabolismo , Material Particulado/farmacologia , Molécula-1 de Adesão Celular Endotelial a Plaquetas/genética , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Titânio/farmacologia , Células U937 , Molécula 1 de Adesão de Célula Vascular/genética , Molécula 1 de Adesão de Célula Vascular/metabolismoRESUMO
Particulate matter (PM) and nanoparticles (NPs) induce activation and dysfunction of endothelial cells characterized by inhibition of proliferation, increase of adhesion and adhesion molecules expression, increase of ROS production, and death. DHEA has shown anti-inflammatory and antioxidant properties in HUVEC activated with proinflammatory agents. We evaluated if DHEA could protect against some inflammatory events produced by PM10 and TiO2 NPs in HUVEC. Adhesion was evaluated by a coculture with U937 cells, proliferation by crystal violet staining, and oxidative stress through DCFDA and Griess reagent. PM10 and TiO2 NPs induced adhesion and oxidative stress and inhibited proliferation of HUVEC; however, when particles were added in combination with DHEA, the effects previously observed were abolished independently from the tested concentrations and the time of addition of DHEA to the cultures. These results indicate that DHEA exerts significant anti-inflammatory and antioxidative effects on the damage induced by particles in HUVEC, suggesting that DHEA could be useful to counteract the harmful effects and inflammatory diseases induced by PM and NPs.
Assuntos
Adjuvantes Imunológicos/farmacologia , Desidroepiandrosterona/farmacologia , Nanopartículas/efeitos adversos , Material Particulado/efeitos adversos , Titânio/efeitos adversos , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Técnicas de Cocultura , Células Endoteliais da Veia Umbilical Humana , Humanos , Inflamação/induzido quimicamente , Inflamação/metabolismo , Inflamação/prevenção & controle , Material Particulado/farmacologia , Titânio/farmacologia , Células U937RESUMO
The effects of particulate matter (PM) on endothelial cells have been evaluated in vitro by exposing isolated endothelial cells to different types of PM. Although some of the findings from these experiments have been corroborated by in vivo studies, an in vitro model that assesses the interaction among different cell types is necessary to achieve more realistic assays. We developed an in vitro model that mimics the alveolar-capillary interface, and we challenged the model using TiO nanoparticles (TiO-NPs). Human umbilical endothelial cells (HUVECs) were cultured on the basolateral side of a membrane and pneumocytes (A549) on the apical side. Confluent co-cultures were exposed on the apical side to 10 µg/cm of TiO-NPs or 10 ng/mL of TNFα for 24 h. Unexposed cultures were used as negative controls. We evaluated monocyte adhesion to HUVECs, adhesion molecule expression, nitric oxide concentration and proinflammatory cytokine release. The TiO-NPs added to the pneumocytes induced a 3- to 4-fold increase in monocyte adhesion to the HUVECs and significant increases in the expression of adhesion molecules (4-fold for P-selectin at 8 h, and about 8- and 10-fold for E-selectin, ICAM-1, VCAM-1 and PECAM-1 at 24 h). Nitric oxide production also increased significantly (2-fold). These results indicate that exposing pneumocytes to TiO-NPs causes endothelial cell activation.
Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Nanopartículas Metálicas , Titânio/farmacologia , Células Epiteliais Alveolares/metabolismo , Adesão Celular/efeitos dos fármacos , Moléculas de Adesão Celular/metabolismo , Linhagem Celular Tumoral , Técnicas de Cocultura , Citocinas/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Óxido Nítrico/metabolismo , Células U937RESUMO
Dehydroepiandrosterone (DHEA), an adrenal steroid, has a protective role against diabetes; however, its mechanisms of action are unknown. Here, we focus on the effect of DHEA on the activation of endothelial cells induced by a high concentration of glucose. Adhesion on U937 cells, expression of adhesion molecules, production of ROS and NO, expression of eNOS, and translocation of NF-κB were evaluated in human umbilical vein endothelial cells (HUVEC) treated with high concentrations of glucose, DHEA, or both. High concentrations of glucose (>20mM) induced an increase in adhesion, an increment in mainly E-selectin and PECAM-1 expression, as well as in ROS and NO production, eNOS expression, translocation of NF-κB, and degradation of its inhibitor IκB-α. DHEA abolished adhesion and the increase of E-selectin, ICAM-1, VCAM-1, and PECAM-1 induced by glucose. In addition, DHEA completely blocked oxidative stress and decreased translocation of NF-κB and the degradation of IκB-α induced by glucose. These results suggest that DHEA protects against the activation of endothelial cells induced by high concentrations of glucose, indicating that DHEA could be useful in the treatment of hyperglycemia and diabetes.
Assuntos
Desidroepiandrosterona/farmacologia , Glucose/farmacologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Adesão Celular , Células Cultivadas , Selectina E/metabolismo , Ensaio de Desvio de Mobilidade Eletroforética , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Proteínas I-kappa B/metabolismo , Molécula 1 de Adesão Intercelular/metabolismo , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Inibidor de NF-kappaB alfa , NF-kappa B/metabolismo , Óxido Nítrico/metabolismo , Estresse Oxidativo , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Transporte Proteico/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Células U937 , Molécula 1 de Adesão de Célula Vascular/metabolismoRESUMO
Vanadium is a transition metal released into the atmosphere, as air-suspended particles, as a result of the combustion of fossil fuels and some metallurgic industry activities. Air-suspended particle pollution causes inflammation-related processes such as thrombosis and other cardiovascular events. Our aim was to evaluate the effect of vanadium pentoxide (V2O5) on endothelial cells since they are key participants in the pathogenesis of several cardiovascular and inflammatory diseases. Cell adhesion, the expression of adhesion molecules and oxidative stress, as well as proliferation, morphology and cell death of human umbilical vein endothelial cells (HUVECs) exposed to V2O5, were evaluated. Vanadium pentoxide at a 3.12 µg cm(-2) concentration induced an enhanced adhesion of the U937 macrophage cell line to HUVECs, owing to an increased expression of late adhesion molecules. HUVECs exposed to V2O5 showed an increase in ROS and nitric oxide production, and a diminished proliferation. These changes in vanadium-treated HUVECs were accompanied by severe morphological changes and apoptotic cell death. Vanadium pentoxide induced serious endothelial cell damage, probably related to the increased cardiovascular morbidity and mortality observed in individuals living in highly air-polluted areas.
Assuntos
Poluentes Atmosféricos/toxicidade , Apoptose/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Compostos de Vanádio/toxicidade , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Técnicas de Cultura de Células , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Óxido Nítrico/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
Correlations between exposure to particle matter (PM) with an aerodynamic diameter Assuntos
Apoptose/efeitos dos fármacos
, Células Endoteliais/efeitos dos fármacos
, Estresse Oxidativo/efeitos dos fármacos
, Material Particulado/toxicidade
, Morte Celular/efeitos dos fármacos
, Linhagem Celular
, Ensaio de Desvio de Mobilidade Eletroforética
, Feminino
, Humanos
, NF-kappa B/genética
, NF-kappa B/metabolismo
, Óxido Nítrico/metabolismo
, Tamanho da Partícula
, Espécies Reativas de Oxigênio/metabolismo
, Translocação Genética
, Fator de Necrose Tumoral alfa/metabolismo
RESUMO
Exposure to PM10 is associated with cardiovascular effects. We evaluated the effects of PM10 on E-Selectin expression and monocytic cell adhesion in human umbilical vein endothelial cells (HUVECs). HUVEC were exposed to PM10 (5-40 microg/cm2) for 6 h, following which surface E-Selectin expression was detected by fluorescence microscopy and flow cytometry. The effects of total particles, particles treated with polymixin-B to block the effects of endotoxin, and both soluble and insoluble fractions of particles, were assessed. Incubation with PM10 lead to a concentration-related increase of E-Selectin expression (>seven-fold increase at 40 microg/cm2). Particles pre-treated with polymixin-B inhibited E-Selectin expression to a level slightly higher than untreated particles. An increase in fluorescence was also observed with the insoluble fraction, while the soluble fraction had no significant effect. HUVEC exposed to PM10 were also evaluated for adhesivity of monocytic cells (U937). PM10 strongly increased the adhesion of U937 cells to HUVEC. In conclusion, PM10 induces endothelial cell activation, evidenced by enhanced E-Selectin expression. This activation is manifested functionally as an increase in monocytic cell adhesion. Insoluble components as well as endotoxins appear to be responsible for this activity.