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Pereira, Flavia Elias. "Role of Sodium Arsenite in Atherogenesis". The University of Montana, 2007. http://etd.lib.umt.edu/theses/available/etd-12282007-163850/.
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Epidemiological studies as well as controlled animal studies have associated exposure to arsenic through drinking water with the development of atherosclerosis. In this study, we have shown for the first time that low and environmentally relevant concentrations of arsenic accelerate atherogenesis. The objective of this study was to elucidate the mechanisms of arsenic-induced atherosclerosis by (1) characterizing the time- and concentration-dependent effects of sodium arsenite [As(III)] on the development of atherosclerosis in ApoE-/- /LDLr-/- mice, (2) determining whether As(III)-induced peroxynitrite activates protein kinase C (PKC) isotypes, α and β, in human aortic endothelial cells (HAECs) and (3) determining the effects of activation of PKC isotypes, α and β, on the endothelial barrier. Accordingly, exposure of ApoE-/- /LDLr-/- mice to As(III) in drinking water showed an increasing trend in atherosclerotic plaque formation in as early as 5 weeks within the innominate arteries. Most remarkable was the evidence that environmentally relevant concentrations of As(III) resulted in significant increase in plaque formation. Initiation of atherosclerosis results from activation/dysfunction of the vascular endothelium that maintains a semipermeable barrier between the blood and vessel wall. To elucidate the mechanism of arsenic-induced atherosclerosis, we analyzed the effect of As(III) on the endothelial monolayer integrity. Endothelial barrier is maintained by proteins of the adherens junction (AJ) such as vascular endothelial cadherin (VE-cadherin) and β-catenin, and their association with the actin cytoskeleton. Treatment of HAECs with As(III) resulted in reorganization of actin filaments into stress fibers and non-uniform VE-cadherin and β-catenin staining at cell-cell junctions. Intercellular gaps were observed with a measured increase in endothelial permeability. In addition, an increase in tyrosine phosphorylation (PY) of β-catenin was observed. These effects were mediated through As(III)-induced activation of PKCα without peroxynitrite formation. No change in PKCβ levels was detected with As(III) treatment. Inhibition of PKCα restored VE-cadherin and β-catenin staining at cell-cell junctions and abolished the formation of intercellular gaps and stress fibers. Endothelial permeability and PY of β-catenin were also reduced to basal levels. These results demonstrate that As(III) induced activation of PKCα causes PY of β-catenin and formation of stress fibers. PY of β-catenin causes weakening of the AJ and this in association with the contractile force generated by stress fibers results in gap formation and increased endothelial permeability. This could potentially accelerate the development of atherosclerosis by increasing the accumulation of oxidized low density lipoproteins and monocytes into the neo-intima of the blood vessel. The findings in this study demonstrate that arsenic disrupts the endothelial monolayer by activation of PKC signaling. Damage to the endothelium plausibly accelerates the process of atherosclerosis at an early stage as evidenced by the increase in atherosclerotic plaques in the ApoE-/- /LDLr-/- mouse model.
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Cox, David Paul. "Disruption of 8-hydroxy-2'-deoxyguanosine DNA Glycosylase (OGG1) Antioxidant Response Capacity by Sodium Arsenite". The University of Montana, 2008. http://etd.lib.umt.edu/theses/available/etd-05272008-134949/.
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8-hydroxy-2'-deoxyguanosine DNA glycosylase is the first step and rate-limiting enzyme involved in the removal of 8-hydroxy-2'-deoxyguanosine via the base excision repair pathway. Transcriptional regulation of human Ogg1 is sensitive to redox changes via modulation of intracellular glutathione. In response to changes in glutathione, changes in hOgg1 transcription occur similar to genes regulated by the transcription factor Nrf2. It was determined that positions - 47 to - 44 in the hOgg1 promoter are necessary for basal transcription of Ogg1 determined by site-directed deletion. This region is capable of interacting with nuclear protein determined by binding assays. Furthermore, transcription factor Nrf2 is identified as binding to this region determined by parallel, and competition EMSA binding assays. Exposure to arsenic has also been associated with oxidative stress and damage to DNA, specifically oxo8dG. This study identified significant increases in the cellular antioxidant glutathione, and alterations in superoxide dismutase activities subsequent to arsenite exposure in actively dividing and NGF treated PC12 cells. Assessment of Ogg1 activity and mRNA levels demonstrated a significant decrease for both measures subsequent to arsenite exposure. The effect seen was due in large part to alterations in gene transcription since direct testing revealed no effect by arsenite on Ogg1 activity. Levels of oxo8dG did not significantly change subsequent to arsenite exposure, however increased trends were evident. Characterization of Sp1 binding revealed that treatment with sodium arsenite could decrease Sp1 binding at two unique Sp1 sites in the human Ogg1 promoter. In summary, transcription factor Nrf2 is an important factor in the inducible regulation of Ogg1. Transcriptional changes in Ogg1 are further dependent on the redox status of the cell. Despite the role of Nrf2 in response to oxidative stress, sodium arsenite disrupted both the transcription and activity of Ogg1 in PC12 cells. This disruption occurred despite the induction of cellular stress response via increases in GSH and Mn SOD activity. This suggests that arsenite is acting through other mechanisms potentially through disruption of the Sp1 transcription factor.
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Mesguida, Ouiza. "Biocontrôle d’un champignon pathogène, Fomitiporia mediterranea, impliqué dans l'Esca, une maladie dévastatrice du bois de la vigne, en utilisant des bactéries isolées de Vitis vinifera". Electronic Thesis or Diss., Pau, 2024. http://www.theses.fr/2024PAUU3054.
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Les maladies du bois de la vigne (MDBs), notamment l'Esca, constituent un enjeu majeur pour la viticulture mondiale. Ces MDBs réduisent la durée de vie des vignobles, impactent la qualité des raisins et donc du vin, entraînant des pertes de revenus estimées à un milliard d'euros par an en France. Aucun traitement curatif n'est disponible depuis l'interdiction de l'arsénite de sodium au début des années 2000, le dernier pesticide chimique homologué pour contrôler les MDBs en Europe. Le développement de méthodes alternatives pour gérer les MDBs, telles que le biocontrôle, est par conséquent de la plus haute importance. Notre objectif a été de sélectionner des bactéries de biocontrôle capables d’inhiber Fomitiporia mediterranea (Fmed), l'un des principaux champignons pathogènes de l'Esca. Ce champignon dégrade le bois de la vigne, conduisant à la formation de la pourriture blanche dans le bois, l’amadou, un symptôme clé de l'Esca, où s'accumulait l'arsénite de sodium. Nos objectifs ont été d’identifier les mécanismes d'action des bactéries sélectionnées, puis d'évaluer leur efficacité au vignoble. Un criblage de 58 souches bactériennes isolées de la vigne a été réalisé in vitro afin d’évaluer leur capacité à inhiber la croissance de six souches de Fmed, via la production de métabolites volatils et diffusibles. Un second criblage a été effectué en microcosme, constitué de sciure de bois de vigne provenant de sept cépages. In vitro, les composés volatils de 51 des 58 souches ont montré une efficacité élevée pour inhiber la croissance de Fmed (>50%). Concernant les métabolites diffusibles, huit souches avaient un niveau d’efficacité similaire. En microcosme, les souches Pseudomonas lactis SV9, Pseudomonas paracarnis S45 et Paenibacillus polymyxa SV13 ont également montré une forte efficacité à inhiber Fmed, elle était cependant dépendante du cépage. Les génomes des trois souches ont été analysés, ainsi que leurs métabolomes par LC-MS/MS pour les composés diffusibles, et par SPME GC-MS pour les volatils. Paenibacillus polymyxa SV13 a inhibé la croissance de Fmed via la production de métabolites diffusibles, tandis que les deux souches de Pseudomonas ont agi principalement via leurs métabolites volatils. Parmi les composés diffusibles produits par P. polymyxa SV13 en présence de Fmed, des molécules de type fusaricidine ayant une activité antifongique ont été identifiés. Pour les métabolites volatils bactériens, les deux souches de Pseudomonas ont produit du disulfure de diméthyle, également connu comme étant un composé antifongique. Les analyses génomiques des trois souches bactériennes ont révélé des groupes de gènes responsables de la régulation des mécanismes d’antagonisme directs et indirects. Pour comprendre le mode d'action de l'arsénite de sodium sur Fmed, le transcriptome du champignon a été examiné lors de son interaction avec ce produit, ouvrant la voie à de futures analyses transcriptomiques lors de l'interaction entre Fmed et les bactéries. Le potentiel de biocontrôle de P. paracarnis S45 et P. polymyxa SV13 a été évalué lors d'un essai au vignoble (cépage Sauvignon Blanc) où ces bactéries ont été injectées dans les troncs de ceps de vigne symptomatiques. Une réduction de la sévérité de l'Esca suite à ces injections a été observée. L'efficacité du traitement variait selon le type de bois injecté, la plus grande efficacité étant observée lors d’injection dans l’amadou. Des analyses de la physiologie de la vigne, de la qualité des baies et du microbiome du bois ont également été réalisées, suite à l’injection de deux bactéries dans le tronc des ceps. Nos résultats soulignent l’importance d’études combinant la sélection d’agents de biocontrôle in vitro, la détermination de leurs modes d’action et l’évaluation de leur efficacité au champ. De futures études pourraient examiner différents modes d’application, et tester différentes formulations d’agents de biocontrôle afin d’améliorer l’efficacité de la protection au vignobleGrapevine trunk diseases (GTDs), particularly Esca, are a major challenge for viticulture worldwide. GTDs decrease the profitable lifespan of vineyards and affect berry and wine quality, leading to an estimated one billion euros in lost revenues annually in France. No curative control treatments are available since the ban of sodium arsenate in the early 2000s, the last chemical pesticide registered to control Esca in Europe. As a consequence, development of alternative methods to manage Esca, such as biological control, has become essential. Our aim was to select bacterial biological control agents (BCAs) effective against one of the main pathogenic fungi of Esca, Fomitiporia mediterranea (Fmed). This fungus degrades grapevine wood acting as a white rot pathogen. White rot is a key symptom of Esca in grapevine wood, where sodium arsenate accumulated after grapevine treatment. Our objectives were to explore the mechanisms of action of selected bacterial strains against Fmed, and subsequently assess their effectiveness in field conditions. A stepwise screening of 58 bacterial strains isolated from grapevine was carried out in vitro for their ability to inhibit the growth of six Fmed strains, through the production of volatile and agar-diffusible metabolites. A second screening was performed on microcosm, made of wood sawdust from seven grapevine cultivars. Fifty-one bacterial strains out of 58 strains tested had high efficacy in inhibiting the growth of Fmed (>50%) through volatile compounds, while eight bacterial strains exhibited strong antifungal efficacy through the production of agar-diffusible metabolites. The strains Pseudomonas lactis SV9, Pseudomonas paracarnis S45, and Paenibacillus polymyxa SV13 demonstrated strong efficacy in inhibiting Fmed in microcosms, in a cultivar-dependent manner. The whole genomes of the three strains were analyzed along with their metabolomes (LC-MS/MS for diffusible compounds and SPME GC-MS for volatile compounds). Paenibacillus polymyxa SV13 inhibited Fmed growth mainly via the production of diffusible metabolites, while the two Pseudomonas strains acted mainly via their volatile metabolites. Among the bacterial diffusible compounds, P. polymyxa SV13 produced mainly fusaricidin-type compounds in the presence of Fmed, compounds known for their antifungal activity. Regarding bacterial volatiles, both Pseudomonas strains produced dimethyl disulfide, which is also known as an antifungal molecule. Genome analyses of the three bacterial strains revealed gene clusters responsible for regulating both direct and indirect mechanisms of action in BCAs. To understand the mode of action of sodium arsenite on Fmed, the transcriptome of the fungus was examined while interacting with this chemical compound, hence paving the way for future transcriptomic analyses during the pathogen interaction with the bacterial BCAs. The biocontrol potential of the two strains P. paracarnis S45 and P. polymyxa SV13 was evaluated in a vineyard trial, by injecting them into the trunks of Esca-symptomatic grapevines of the cultivar Sauvignon Blanc. This study demonstrated a reduction in Esca severity after trunk injections of P. paracarnis S45 or P. polymyxa SV13. Treatment efficacy varied depending on the type of wood tissue injected, with the greatest efficacy observed when injected into white-rot. Analyses of grapevine physiology, berry quality and wood microbiome were also carried out, following the injection of the two bacteria into the trunk of the grapevines. Our results highlight the importance of studies combining the selection of biological control agents in vitro, deciphering their modes of action and the evaluation of their efficacy in the field. Future research could focus on optimizing application methods and refining biocontrol formulations to further enhance their effectiveness
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Aquino, Ariana Musa. "Efeito da exposição pré-puberal ao arsênio sobre parâmetros morfofuncionais na próstata ventral de ratos pubescentes". Botucatu, 2019. http://hdl.handle.net/11449/181437.
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Orientador: Wellerson Rodrigo ScaranoResumo: O arsênio é um metaloide associado ao desenvolvimento de algumas patologias, como doenças cardiovasculares, lesões dérmicas e diferentes tipos de câncer. Pouco se sabe sobre a ação do arsênio ou compostos de arsênio na próstata durante o período pré-puberal e puberdade, estágios essenciais para a morfogênese tardia da próstata. Nesse sentido, este estudo teve como objetivo estabelecer se a exposição ao arsenito de sódio (NaAsO2) interfere na morfofisiologia da próstata ventral de ratos púberes. Para isso, 30 ratos machos da linhagem Wistar, no dia pós-natal 23 (DPN23), foram distribuídos, aleatoriamente, em 3 grupos experimentais (n =10/grupo). O grupo controle (Ctrl) recebeu água filtrada (veículo); o grupo As1 recebeu 0.01 mg/L de NaAsO2; e o grupo As2 recebeu 10.0 mg/L de NaAsO2. Todas as soluções foram diluídas na água do bebedouro e estiveram disponíveis aos animais do DPN23 ao DPN53. Os hábitos alimentares e a evolução do peso corpóreo dos animais foram acompanhados durante todo o período experimental. Ao final deste período, os animais foram pesados e, em seguida, eutanasiados (DPN53). Coletou-se o sangue para mensurar os níveis de testosterona. O fígado, os rins e a próstata ventral (PV) foram coletados e pesados. Apenas a PV foi dissecada e destinada às análises histológicas (hemilobo esquerdo) e moleculares (hemilobo direito). Os resultados dos parâmetros analisados durante o período experimental revelaram que o NaAsO2 não foi capaz de causar toxicidade sistêmica em... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Arsenic is an endocrine disruptor associated with the development of some pathologies such as cardiovascular diseases, dermal lesions and different types of cancer. Little is known about the action of arsenic or arsenic compounds in the prostate during the prepubertal and puberty period, an essential stage for late morphogenesis of the prostate. Therefore, this study aimed to establish whether exposure to sodium arsenite (NaAsO2) interferes in the morphophysiology of the ventral prostate of pubertal rats. In this study, thirty male Wistar rats, on the postnatal day 23 (PND23), were randomly distributed to 3 experimental groups (n = 10/group). The control group (Ctrl) received only saline solution; the second group (As1) received 0.01 mg/L of NaAsO2; and the third group (As2) received 10.0 mg/L of NaAsO2. All solutions were diluted in drinking water and were available to the animals from DPN23 to DPN53. The eating habits and the evolution of the body weight of the animals were evaluated throughout the experimental period. At the end of this period, the animals were weighed and then euthanized (DPN53). Blood was collected to measure testosterone levels. The liver, kidneys and ventral prostate (VP) were collected and weighed. Only VP was dissected for histological analysis (left hemilobo) and molecular (right hemilobo). The results of the parameters analyzed during the experimental period revealed that NaAsO2 was not able to cause systemic toxicity in both exposed groups nor cha... (Complete abstract click electronic access below)
Mestre
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Steffens, Amanda Ann. "Low-dose of sodium arsenite causes delayed differentiation in C2C12 mouse myoblast cells through the repression of the transcription factor myogenin". Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1263410069/.
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Winski, Shannon Lee 1967. "Metabolism and toxicity of sodium arsenate in human erythrocytes". Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282320.
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Toxicity of arsenic species is dependent on chemical oxidation state. Inorganic arsenic in the trivalent state, arsenite or As(III), is more biologically active than pentavalent arsenic, arsenate or As(V), and is more toxic by most measures. As(V), however, is more stable and prevalent in the environment. One consequence of environmental exposure is peripheral vascular disease, which is primarily due to vascular changes, but toxicity to the erythrocyte has not been evaluated. To understand toxicity and the implications of arsenic oxidation state, human erythrocytes were utilized to model the uptake, biotransformation (metabolism) and toxicity of sodium arsenate, As(V). It was first established that biotransformation, both in vivo and in vitro, would not be limited by uptake of As(V) into the cell. Evidence suggested that reduction was accomplished by at least two separate pathways. All reductive metabolism was dependent on the presence of reduced thiols including both non-protein thiols (glutathione; GSH) and protein thiols (ProSH). These pathways are: (1) chemically mediated reduction by GSH and (2) protein mediated reduction. It was established that the protein-dependent pathway required a reduced protein thiol and also required the presence of GSH. This points to reduction through a redox coupling to form a protein mixed disulfide (ProSSG). Toxicity to the erythrocyte was evaluated by determining total cell death, morphologic changes and effects on the energy cofactor adenosine triphosphate (ATP). Based on these three parameters, the erythrocyte was more susceptible to As(V) and not As(III) as other tissues are. The morphologic effects on the cell were also consistent with ATP depletion. These changes were characterized by formation of morphologically altered cells that are unable to deform in circulation effectively and occlude the microcirculation. This could contribute to vascular tissue damage associated with arsenic-induced circulatory disorders. In summary, the erythrocyte is able to take in As(V) which is detrimental to the ability of the cell to perform its intended function. Biotransformation to As(III) would therefore be a detoxifying event, and understanding the factors involved in biotransformation will help to understand human susceptibility to arsenic-induced vascular disease.
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Li, Wen. "Synthesis and solubility of arsenic tri-sulfide and sodium arsenic oxy-sulfide complexes in alkaline sulfide solutions". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44546.
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Alkaline sulfide leaching (ASL) at approximately 100 ºC has been used to selectively extract arsenic and antimony from enargite and tetrahedrite concentrates. Sodium thio-arsenate has been postulated to crystallize from alkaline sulfide leaching solutions upon cooling. However, literature data on the solubility of sodium thio-arsenate as well as proof of its crystallization from ASL solutions is scant. In this thesis, the solubility of leach-produced and synthetic sodium thio-arsenate is studied.
To determine arsenic solubility in ASL solutions, sodium thio-arsenate and sodium arsenic oxide sulfide complexes are synthesized by various means and characterized by EDX, QXRD, and ICP.
The synthesis of amorphous As₂S₃, sodium arsenic oxy-sulfide complexes, and sodium thio-arsenate is first presented. For amorphous As₂S₃ synthesis, the effect of concentration of sodium sulfide (0.1 M) and hydrochloric acid (1 M), temperature (40 ~ 60 ºC), and aging time (48 hours) was optimized. The solubility of synthetic sodium arsenic oxy-sulfide complexes and sodium thio-arsenate in ASL solutions increases significantly as temperature is increased to 95 ºC. More importantly, the solubility of sodium thio-arsenate at certain temperatures is significantly affected by the concentration of sodium hydroxide and sulfide in solution. Due to the common ion effect, if NaOH and HS- concentrations are very high, the solubility of sodium thio-arsenate decreases.
Enargite leaching tests were done to characterize the precipitate that occurred upon cooling and to verify the arsenic saturation point, which should be between 38.5 ~ 58 g/L (0.51 M ~ 0.78 M) As depending on the NaOH and HS- concentration. Comparison with solubility experiments of pure sodium thio-arsenate shows that arsenic solubility in ASL solutions is supersaturated. However, direct comparison of saturation in ASL solutions and the solubility as obtained by the synthetic solutions/crystallites prepared here is not possible given the complex nature of the ASL crystallites that appear not to contain the often discussed “sodium thio-arsenate”.
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OLIVEIRA, GLEN A. M. de. "Estudo comparativo do efeito analgésico do laser em baixa intensidade de emissão infravermelha e da pasta de fluoreto de sódio a 33 porcento no tratamento da hipersensibilidade dentinária". reponame:Repositório Institucional do IPEN, 2003. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11335.
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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo
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Pickering, Edmund Ian Marcus. "Mechanical characterisation of nanowires through resonance techniques". Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/123008/1/Edmund_Pickering_Thesis.pdf.
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This thesis uses the mechanical resonance technique to investigate and characterise the mechanical behaviour of nanowires. While previous work has mainly focused on simple, uniform nanowires, this thesis extends the resonance technique to incorporate more complex morphologies. Specifically, tapered nanowires with surface effects and curved nanowires with irregular cross-sections were investigated through experiments and modelling. This works will aid in advancing the pace of nanowire development by extending the resonance technique to describe such nanowire morphologies.
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AVEGLIANO, ROSEANE P. "Estudo de dieta total no estado de Sao Paulo: estimativa de ingestao dietetica de elementos toxicos (arsenico e cadmio) e essenciais (calcio, cromo, ferro, selenio, sodio, potassio e zinco)". reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11523.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Macedo, Luciene Fagundes Lauer. "Remoção de mercúrio e arsênio em cação-azul, Prionace glauca". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-19012011-102635/.
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Os cações são importantes recursos pesqueiros que podem apresentar concentrações de mercúrio (Hg) e arsênio (As) muitas vezes acima do limite de tolerância, o que os tornam impróprios como alimento. No meio aquático estes contaminantes são convertidos em espécies orgânicas, em especial metilmercúrio (MeHg) e arsenobetaína (AB), respectivamente. O MeHg é neurotóxico, sendo o sistema nervoso em desenvolvimento o mais susceptível. A AB é pouco tóxica, no entanto, o As inorgânico está envolvido em processos de estresse oxidativo, mutagênese e principalmente carcinogênese. Neste trabalho, foi avaliada a eficiência da cisteína na remoção de Hg, a ocorência de As total e inorgânico, e a redução de sua concentração com o emprego de borohidreto de sódio e de preparos para o consumo. A redução máxima de Hg, de 59,4%, com cisteína a 0,5% em pH 5,0, não foi reproduzida quando pretendida a reutilização da solução do aminoácido, importante do ponto de vista prático. O cação-azul continha elevados níveis de As total, 1,98 a 22,56 µg/g (base úmida), que foram removidos com borohidreto de sódio em 99%, demonstrando a alta potencialidade do método usado. O As inorgânico, presente na quantidade média de 0,0086 µg/g (base úmida), foi reduzido em 27,7%. O preparo para o consumo, por cozimento em água, do cação-azul em cubos (1-2 cm3), resultou em maior remoção de As total, de 65,9 a 71,2%; no cação grelhado a redução foi de 55,4 a 60,2%. As amostras, grelhadas ou cozidas, adicionadas de sal e limão enriquecido com ácido ascórbico, e as grelhadas contendo sal e sal com limão, apresentaram redução na concentração de As inorgânico de 30,1 a 42,8%.The shark are important fishery resources that may have concentrations of mercury (Hg) and arsenic (As) often above the limit of tolerance, which makes them unsuitable as food. In the aquatic environment these contaminants are converted to organic species, particularly methylmercury (MeHg) and arsenobetaína (AB), respectively. The MeHg is neurotoxic, and the developing nervous system more susceptible. AB is slightly toxic, however, the inorganic As is involved in processes of oxidative stress, mutagenesis and carcinogenesis mainly. In this study, we evaluated the efficiency of cysteine to remove mercury, the occurrence of the total and inorganic As, and the reduction of their concentration with the use of sodium borohydride and preparations for consumption. The maximum reduction of Hg, 59.4%, with 0.5% cysteine at pH 5.0, was not reproduced when you want to reuse the solution of the amino acid, important practical point of view. The blue-shark contained high levels of the total As, 1.98 to 22.56 µg/g (wet weight), which were removed with sodium borohydride in 99%, demonstrating the high potential of the method used. The inorganic As, present in the average amount of 0.0086 µg/g (wet weight) was reduced in 27.7%. Preparation for consumption by baking in water, the blue-shark into cubes (1-2 cm3) resulted in greater removal of the total As, 65.9 to 71.2%; in the grilled shark the reduction was 55,4 to 60.2%. The samples, grilled or baked, added salt and lemon enriched with ascorbic acid, and the grilled containing salt and salt with lemon, presented reduction in the concentrations of inorganic As from 30.1 to 42.8%.
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LIN, YING-JUN y 林盈君. "The genotoxicity of sodium arsenite". Thesis, 1988. http://ndltd.ncl.edu.tw/handle/91603457637818644886.
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HUANG, RUI-YA y 黃瑞雅. "The cogenotoxicity of sodium arsenite". Thesis, 1986. http://ndltd.ncl.edu.tw/handle/18705607774501942224.
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Bau, Da-Tian y 包大. "Effect of sodium arsenite on DNA repair". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/22287856129687929489.
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博士國防醫學院
生命科學研究所
90
Chronic arsenite exposure is believed to be related to a wide variety of human disorders, including cancers. Arsenite has been reported to induce chromosome aberrations, to enhance the genotoxicity of several other mutagens, and to inhibit DNA repair. Since inhibition of DNA repair can increase genotoxicity, the co-genotoxicity of arsenite may be related to its inhibition of DNA repair. Since DNA integrity is important for cells to maintain their normal functions, the effects of arsenite on DNA integrity may play a role in the etiology of arsenic-related human disorders. The purpose of this research was to investigate the mechanisms of how arsenite inhibits DNA repair. By using DNA synthesis inhibitors to accumulate DNA strand breaks, and enzyme-incorporated comet assay to reveal DNA adducts, the inhibitory effect of arsenite on the DNA adduct excision and DNA strand break rejoining in human fibroblasts was studied. The results indicate that arsenite inhibited DNA adduct excision induced by UVC, 4-nitroquinoline 1-oxide and X-ray, but not by methyl methanesulfonate, hydrogen peroxide, sodium nitrosoprusside or 3-morpholinosydnonimine. Conversely, arsenite inhibited the DNA strand break rejoining induced by X-ray, methyl methanesulfonate, and hydrogen peroxide, but not by UVC, or 4-nitroquinoline 1-oxide. The experiments using modulators and donors indicate that nitric oxide and superoxide were involved in arsenite inhibition of DNA adduct excision, whereas, hydrogen peroxide was involved in arsenite inhibition of DNA strand break rejoining. This notion is consistent with the observation that treating human fibroblasts with arsenite also increased the production of nitric oxide and hydrogen peroxide. So far, the results suggest that arsenite inhibited adduct excision in nucleotide excision repair via nitric oxide and superoxide, whereas, arsenite inhibited DNA strand break rejoining in base excision repair via hydrogen peroxide. The result of comparing the relative inhibitory potency of arsenite on the DNA repair induced by UVC, 4-nitroquinoline 1-oxide, methyl methanesulfonate, and hydrogen peroxide, indicates that the excision of UVC-induced pyrimidine dimers was most sensitive to arsenite inhibition. Apparent inhibition could be detected with 0.5 mM arsenite. In addition to human fibroblasts, Chinese hamster ovary cells are also widely used for DNA repair studies. Therefore, the effect of arsenite on the excision of pyrimidine dimers was reexamined in Chinese hamster cells. Since binding to thiols, induction of reactive oxygen species, and induction of nitric oxide are currently the three major hypotheses for the mechanisms of arsenite toxicity, the question “which of these three pathways is involved in arsenite inhibition of UVC-induced DNA repair? was asked. By using the host cell-mediated DNA repair assay, the results show that arsenite inhibitory effect on UVC-DNA repair can be suppressed by nitric oxide synthase inhibitors. Arsenite also increased nitric oxide production and nitric oxide generators also inhibited UVC-DNA repair. Thus the involvement of nitric oxide in arsenite inhibition of pyrimidine dimer excision was confirmed in Chinese hamster ovary cells. On the other hand, the results of experiments on the effect of oxidant modulators didn’t give a clear indication that reactive oxygen species are involved in arsenite inhibition of UVC-DNA repair. Phenylarsine oxide, a strong thiol-reacting agent, didn’t inhibit pyrimidine dimer excision or UVC-DNA repair and also didn’t increase nitric oxide production. The results show conclusively that nitric oxide is involved in the inhibition of pyrimidine dimer excision by arsenite. While arsenite inhibited pyrimidine dimer excision in both Chinese hamster ovary cells and human fibroblasts, arsenite inhibited DNA strand break rejoining in UVC-irradiated Chinese hamster ovary cells but not in human fibroblasts. Therefore, different mechanisms may have involved in the UVC-induced DNA strand break rejoining in human and rodent cells. Moreover, it is well recognized that hamster cells repair UVC-induced DNA damage less efficiently than human cells. Rodent cells are proficient in the removal of 6-4 pyrimidine-pyrimidone photoproducts from the overall genome but the cyclobutane pyrimidine dimers are removed only from the transcribing strand of active genes. However, the results indicate that Chinese hamster ovary cells repaired UVC-induced T4 UV endonuclease V-digestible adducts efficiently. It is also known for some time that the genetic damage induced by UVC is primarily cyclobutane pyrimidine dimers (65-90%) and 6-4 pyrimidine-pyrimidone photoproducts (10-35%). It is true in human fibroblast, however, the results indicate that, in addition to T4 UV endonuclease V-digestible adducts, UVC also induced substantial amount of formamidopyrimidine-DNA glycosylase- and proteinase K-digestible adducts in Chinese hamster ovary cells. The biological significance of these adducts is largely unknown. By using enzyme-incorporated comet assay, arsenite was found to induce DNA adducts at similar concentration range as its inhibition of DNA repair in human fibroblasts. Therefore, induction of DNA damage and inhibition of DNA repair seem to be equally important and they may act in concert to cause human disorders. In human vascular smooth muscle cells, arsenite has been shown to induce oxidative DNA damages via activation of NADH oxidase. However, the effect of arsenite on the induction of DNA damage in human umbilical vein endothelial cells remains unknown. Since endothelial and smooth muscle cells are two most important target cells in atherosclerosis, the induction of DNA damage by arsenite in both human umbilical vein endothelial cells and vascular smooth muscle cells was investigated. Arsenite induced formamidopyrimidine-DNA glycosylase-digestible DNA adducts in both human umbilical vein endothelial cells and vascular smooth muscle cells. Surprisingly, arsenite also induced T4 UV endonuclease V-digestible DNA adducts in human umbilical vein endothelial cells, but this was not observed in vascular smooth muscle cells. Moreover, while arsenite induction of formamidopyrimidine-DNA glycosylase-digestible DNA adducts in umbilical vein endothelial cells was sensitive to the inhibitors of nitric oxide synthase, it was insensitive to catalase. Conversely, arsenite induction of formamidopyrimidine-DNA glycosylase-digestible adducts in vascular smooth muscle cells was sensitive to catalase, but it was insensitive to nitric oxide synthase inhibitors. These data suggest that arsenite may induce different types of DNA adducts in umbilical vein endothelial cells and vascular smooth muscle cells via different pathways. Since arsenic intoxication as well as sensitivity to arsenite is cell-specific, it is important that target tissues and cells are used for further investigations.
15
Yi, Chang Hsin y 張欣怡. "Stress response in human fibroblasts after treatment with gallium arsenide and sodium arsenite". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/85463634361296025680.
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碩士國立清華大學
生物技術研究所
91
English abstract While cytotoxic effects of individual gallium arsenide were well documented, the direct investigation of cytotoxic effects of dissolved gallium arsenide compound is largely unexplored. Here I showed that the cytotoxic and genotoxic effect of the long-term gallium arsenite treatment of human fibroblast cells. I also compare the influence on human fibroblasts after sodium arsenite treatment to gallium arsenide treatment. This study also proves that cells increase cellular ROS levels when human fibroblast cells were treated with these chemicals for 4 h and 12 h. In my laboratory, it had been examined that short-term exposure (4 h) of human fibroblast cells to gallium arsenide exhibit genotoxic micronuclei (MN) formation, and cytotoxic effect. Further more, I also demonstrated that long-term exposure (12 h) of human fibroblast cells to gallium arsenide exhibit genotoxic micronuclei (MN) formation, and cytotoxic effect. In addition, the p53, HO-1 and p21 protein expression was examined after 0-80 μM sodium arsenite or gallium arsenide treatment. Generally, p53 expression raises at 0-40 μM NaAsO2 and GaAs. When cells exposed to arsenic compound, largely induce HO-1 expression. After sodium arsenite or gallium arsenide treatment for 4 h, the number of cells at the cell cycle arrest at G2/M phase increases with the treatment dose. After 40 μM sodium arsenite treatment for 12 h, partial cells of a population precede program cell death. The gallium arsenide treatment groups have this phenomenon until the gallium arsenide concentration increase to 80 μM。
16
PENG, GIAN-LI y 彭千里. "Action stage of the coclastogenicity of sodium arsenite". Thesis, 1988. http://ndltd.ncl.edu.tw/handle/51518578188241424725.
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jui-chou, Cheng y 鄭瑞洲. "Sodium arsenite induces oxidative stress in human cells". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/88430827838193054134.
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碩士國立臺灣大學
動物學系
81
Many experimental evidences have supported that arsenite- induced toxicity is associated with the generation of free radicals, e.g. arsenic induces lipid peroxidation, sister chromatid exchanges, heme oxygenase (HO), glutathione S- transferase and glutathione (GSH). In our experiments, antioxidants were assessed in arsenite-treated KB cells. GSH contents was increased to 180 % of the control and it was rapidly increased during early 4 h treatment. HO was induced in a dose-dependent way and the maximal induction of HO was observed during 4 to 6 h treatment. Moreover, tin-protophyrin (SnPP), an HO inhibitor, can enhanced the cytotoxicity of arsenite, indicating that HO may play an important role in reducing the cytotoxicity of arsenite. In arsenite-treated KB cells, induced HO can be degraded very rapidly by posttreatment of SnPP. Superoxide dismutase (SOD) activity was not changed. Catalase activity was decreased to 60 % of the control and it was decreased by time-dependently. These results indicated that arsenite may result in the imbalance of free radicals in cells. In addition, our results have also shown that arsenite can induce the accumulation of H2O2 in human KB and HL 60 cells by using dichlorofluorescein (DCF) fluorescence spectrophotometry. However, the survival of arsenite-treated cells can not be notablely raised by catalase. These results suggested that arsenite may caused disturbances of cellular antioxidants and result in the accumulation of H2O2 which may not involved in arsenite cytotoxicity.
18
Ling-Huei, Yih y 易玲輝. "Induction of Cytogenetic Alterations by Sodium Arsenite in Human Fibroblasts". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/13473726570798038351.
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博士國防醫學院
生命科學研究所
86
According to epidemiology studies, arsenic compounds are recognized as human carcinogens. The cellular and molecular mechanism(s) of arsenic carcinogenicity is yet not clear. Human population with chronic arsenic exposure through drinking water ingestion show increased frequencies on chromosome aberrations and sister chromatid exchanges and increased risks for cancers of skin, lung, liver, bladder, and prostate. Although arsenite-induced cell morphological transformation is associated with cytogenetic alterations, the underlying mechanisms of arsenite-induced cytogenetic alterations remain obscure. Arsenite is inactive or too weak to induce gene point mutations, arsenite-induced cytogenetic alterations may play a crucial role in arsenic carcinogenicity. Previous studies have shown that treatment of 10 - 80 uM arsenite for 4 h induces chromosome aberrations, sister chromatid exchanges, and micronuclei via the induction of oxidative stress. In this thesis, evidence has shown that chronic (0 - 5 uM for 24 h) and acute (10 - 40 uM for 24 h) arsenite treatment resulted in different cytogenetic alterations. Chronic treatment with arsenite induced kinetochore- positive micronuclei (K+-MN) and c-anaphases probably via the alteration of mitosis, whereas acute treatment induced kinetochore-negative micronuclei (K--MN) and chromatid breaks probably via the induction of oxidative stress. Further analysis of arsenite''s effects on mitosis progression has shown that treatment of HFW cells at G2 phase with 5 uM arsenite resulted in the accumulation of cyclin B and inhibition of cdc25C phosphorylation and cdc2 dephosphorylation and led to G2 arrest. Arsenite also induced mitotic spindle derangement and chromosome segregation alterations and resulted in mitotic arrest. These deleterious effects of arsenite might lead to chromosome loss and chromosome instability in daughter cells. C-anaphases, a type of abnormal chromosome segregation, may lead to anuploidy. Treatment of HFW cell wit 5 mM arsenite for 18 h could induce c-anaphases. Treatment of nocodazole- or taxol-induced mitotic cells with arsenite also induced c-anaphases. These results indicate that arsenite could interfere with chromosome segregation during mitosis. Staurosporine, a protein kinase inhibitor, was found to reduce arsenite-induced c-anaphases, indicating that arsenite might disturb the cascades of cellular protein phosphorylation and dephosphorylation and result in abnormal chromosome segregation. These results showed that arsenite might alter protein phosphorylation status and disturb the function of mitosis regulating proteins which might result in abnormal mitosis and lead to the induction of chromosome instability. Chromosome instability is important and possibly essential in multistep carcinogenesis. Arsenite may thus invovled the initiation, promotion, and progression steps in carcinogenesis.
19
lien, Tseng Yu y 曾玉蓮. "Sodium arsenite enhances the cytotoxicity of cisplatin to mammalian cells". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/11853195325956190541.
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Hsu, Hsin-Hua y 徐新華. "Preparation of Monoclonal Antibody against Arsenic Resistant Cell Line-SA7 and Mnoclonal Antibody against Sodium Arsenite". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/33570641686829938031.
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碩士國立中央大學
生命科學研究所
86
SA7細胞為一篩選自中國倉鼠卵巢細胞(CHOA, Chinese hamster ovary cells)之抗砷細胞株.本實驗之目的在於製備對抗砷細胞株以及對抗亞砷 酸鈉之單株抗體,探討動物細胞的砷排除機制.以SA7細胞膜蛋白免疫Bala/ c老鼠,利用融合瘤技術經過酵素免疫分析法篩選,得到對CHOA細胞反應較 強的單株抗體M1G8(A)H12A E4 (M1G8-E4).由西方點墨法證明,此一單株抗 體對CHOA細胞中一約40 kDa之蛋白質具有專一性.在經過亞砷酸鈉(10-40 uM, 24小時)或醋酸鎘(20 uM, 24小時)處理後,其在細胞中的含量會明顯 增加,而在SA7細胞中則不見此蛋白質表現.CHO-K1,SA7N及人類口腔癌細 胞(KB, oral epidermoid carcinoma)與肝癌細胞(Hep G2, hepatocellular carcinoma)經亞砷酸鈉(10-40 uM, 24小時)或醋酸 鎘(20-40 uM, 24小時)處理後,也有類似的蛋白質表現.為了進一步研究此 蛋白質與亞砷酸鈉之關係,將CHOA,CHO-K1及SA7N以不同濃度之亞砷酸 鈉(10-30 uM)培養六天後,此40 kDa左右的蛋白質並未消失.將SA7細胞培 養於一般培養液,也未見此蛋白質的出現.由免疫細胞化學染色發現許多螢 光亮點分布於CHOA細胞上.嘗試以M1G8-E4-Protein-A膠體管柱純化此40 kDa之蛋白質,但未成功.此外用keyhole limpact hemocyanin(KLH)- lipoic acid-arsenite(KLA)免疫Balb/c老鼠,篩選到6株單株抗體,以其 中3株融合瘤細胞,經過不同的亞砷酸鈉-蛋白質結合物,進行酵素免疫分析 法以及用競爭性酵素免疫分析發現,此3株單株抗體只能與接合在lipoic acid及BSA之亞砷酸鈉有反應,而與BSA本身或BSA-lipoic acid結合體本身 並無反應.以單株抗體探討砷化物所造成之毒性,值得更進一步研究. The thesis was aimed to generate monoclonal antibodies specifically reacted with arsenic-resistant Chinese hamster ovary(CHOA) cells,SA7. The Balb/c mice were immunized with plasma membrane protein of SA7 cells, and the spleen cells were fused with P3 myeloma cells. After enzyme-linked immunosorbent assay(ELISA), one hybridoma generating monoclonal antibody,M1G8, preferentially reacted with CHOA cells was cloned. By Western blotting analysis, M1G8(A)H12A E4(M1G8-E4)recognized a 40 kDa protein present in CHOA cells, but not SA7 cells . After sodium arsenite(20-40 um, 24hr)or cadmium acetate(20 uM, 24hr) treatment, expression of the 40 kDa protein was enhanced in CHOA, CHO-K1 and SA7N(a revertant of SA7 cells)cells as demonstrated by Western blotting technology. Treatment of KB and Hep G2 cells with arsenite(20 uM. 24hr)or cadmium acetate(40 uM, 24hr)also induced a 40 kDa protein recognized by the monoclonal antibody M1G8-E4. SA7 cells were routinely cultured in arsenite-containing medium, however, treatment of CHOA,CHO-K1 and SA7N cells with arsenite(10-30 uM)for 6 days did not downregulate the 40 kDa protein expression. Furthermore, heat shock (45 degree c,5-20 minutes)treatment also enhanced expression of the 40 kDa protein in CHOA and CHO-K1 cells, indicating that the 40 kDa protein is a heat shock protein. By immunocytochemistry assay, the 40 kDa protein was predominately presented in CHOa cells, but nit in SA7 cells. An attempt was also made to purify the 40 kDa protein by M1G8-E4-Protein -A affinity chromatography, but unfortunately failed. This thesis also aimed to generate monoclonal antibodies against sodiumarsenite. After immunizing Balb/C mice with keyhole limpact hemocyanin(KLH)-lipoic acid-arsenite(KLA)conjugate, the hybridoma technique was performed and 6 monoclonal antibodies specifically reacted with bovine serum albumin(BSA)-lipoic acid- arsenite(BLA), but not BSA or BSA-lipoic acid, were obtained. Three of the six monoclonal antibodies were selected for further characterized.By competitive ELISA, the reaction of monoclonal antibodies with BLA did not affect by arsenite-lipoic acid(0-800 uM)or arsenite(0-800 uM), suggesting thatthe epitope of these monoclonal antibodies recognized was not only arsenite molecule, but arsenite conjugating with BSA-lipoic acid. The application of these monoclonal antibodies in arsenite toxicity study warrants further investigation.
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簡佳雯. "Molecular basis of sodium arsenite tumorigenicity in human skin HaCaT cells". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/20560242302942028516.
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江明璋. "(Study of sodium arsenite-induced neoplastic transformation in human skin HaCaT cells)". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/19031737534502696012.
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碩士國立中央大學
生命科學研究所
89
Arsenic is a naturally occurring constituent of soil and water, and arsenic metalloid is widely used in industry. The combination of lengthy environmental persistence with widespread arsenic contamination contributes to a high exposure incidence among human populations. Arsenic is a human carcinogen. With ingestion of inorganic forms of this metalloid causes primarily skin cancer, but also cancers of the bladder, liver, and kidney. However inorganic arsenic fails to induce tumors in most laboratory animals. To explore the mechanisms of arsenic carcinogenesis, we have investigated the growth property and gene expression profile in spontaneously immortalized human skin keratinocytes (HaCaT), that were continuously exposed to non-toxic doses of arsenite (0.5 and 1 mM) for approximately 6 months. Through a continuous exposure of HaCaT to non-toxic doses of arsenite(0.5 and 1 mM) for several months, HaCaT cells became apparently tumorigenic in nude mice. In addition, we have observed the following changes caused by long term exposure to arsenite: (1) higher colony forming efficiency on soft agar; (2) higher cell density at confluency; (3) more population doublings in each passage; and (4) higher levels of GSH. By Western blotting analysis, c-fos, c-jun, keratins, catalase, heme oxygenase-1 and adhesion molecular galectin-1 were inhibited in arsenite-exposured cultures. By using a colorimetric cDNA microarray analysis, we found that the expression of dihydrodiol dehydrogenase, ferritin, thioredoxin peroxidase, oxidation resistance-1 and glutamate-cysteine ligase were enhanced in 1 mM arsenite-exposured cultures. We also found that the transmembrane protein(63kD) ,catenin a2, gelsolin, caveolins and keratin 14 were decreased in 1 mM arsenite-exposured cultures. These results suggest that after long-term and low dose exposure of HaCaT cells to arsenite leads to alterations in the expression profile and tumor formation in nude mice. We have investigated the carcinogenesis in low concentration arsenite in vivo in non-tumorigenic HaCaT cells, which were subcutaneously injected into SCID mice. Through a continuous exposure of low dose arsenite (50, 100, 200 and 500 ppb) to SCID mice for approximately 5 months, HaCaT cells became apparently tumorigenic in SCID mice. This animal model may be valuable for further investigation in molecular mechanisms of arsenic carcinogenicity.
23
Kao, Ying-Hsien y 高英賢. "Biological effects of sodium arsenite on cultured human umbilical vein endothelial cells". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/16182766973514359523.
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碩士高雄醫學大學
醫學研究所
89
Arsenic is widely distributed in nature and frequently concentrated and released into the environment through industrial processes and agricultural usage such as primary copper, zinc and lead smelters, glass manufacturers, and chemical manufacturers. Drinking water contamination by arsenic remains a major public health problem. Acute and chronic arsenic exposure via drinking water has been reported in many countries of the world; especially in Argentina, Bangladesh, India, Mexico, Thailand, and Taiwan, where a large proportion of drinking water (ground water) is contaminated with a high concentration of arsenic. There were sufficient evidence from epidemiological studies to support a causal association between arsenic exposure and human diseases. General health effects that are associated with arsenic exposure include higher mortality ratio with cardiovascular disease such as atherosclerosis. Arsenic exposure also leads to degenerative peripheral vascular disease like blackfoot disease. In addition, research pointed out significantly higher standardized mortality ratios and cumulative mortality rates for cancers of the bladder, kidney, skin, liver, and colon in many areas of arsenic pollution. Others include developmental anomalies, neurologic and neurobehavioral disorders, portal fibrosis of the liver, and lung fibrosis. The purpose of this study was to investigate whether arsenic participates in the regulation of cell proliferation and other patho- and physiologic functions in vascular endothelial cells, and particularly focused on angiogenesis - one form of differentiation specific to endothelial cells. The results revealed that sodium arsenite (SA) exhibits typical biphasic biological effects on cell growth. Lower concentration (up to 1 M) of SA stimulates HUVEC proliferation. Similarly, in vitro angiogenesis assay indicated that low concentrations of SA maintain the morphogenesis of vascular tubular formation, whereas high concentration of SA revealed cytotoxic inhibition. We also demonstrated that lower concentration of SA can upregulate the expression of constitutive nitric oxide synthase (eNOS) at both transcriptional and translational levels, and that lower concentration of SA implicated a modulatory role in VEGF expression. Additionally, lower concentration of SA (<1 M) could stimulate the vWF antigen expression. vWF was demonstrated to be an indicator of representing the activation of endothelium in tumor tissue, which paralleled with the onset of angiogenesis preceding the tumor metastasis. In vitro study also demonstrated that two angiogenic factors, VEGF and bFGF, can synergistically upregulate the vWF gene expression. Therefore, we conclude that the treatment of HUVEC with SA leads to the cell proliferation and activation, which preferentially enhances the angiogenesis in vitro. The molecular mechanism(s) by which arsenic facilitates angiogenesis, however, remain to be elucidated. 二、 英文摘要……………………………… 3 三、 英文縮寫……………………………… 5 四、 前 言……………………………… 8 五、 材料與方法…………………………… 20 六、 研究結果……………………………… 32 七、 討 論……………………………… 36 八、 結論與展望…………………………… 39 九、 參考文獻……………………………… 40 十、 圖 表……………………………… 54
24
Fan, Chiu-Ting y 范秋婷. "Inhibition of glutathione reductase by sodium arsenite-induced nitric oxide in human fibroblast". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/76367427024444175459.
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碩士國立清華大學
生命科學系
90
Human fibroblasts were exposed to sodium arsenite for 4h. The cytotoxicity of sodium arsenite treatment was determinted by SRB assay. The IC50 was 30μM- 40μM. Here, the cell survival was only 20﹪of control in the exposure of 80μM sodium arsnite. This study has shown that sodium arsnite influence the cytotoxicity of HF. Treatment of HF with SA40-160μM for 4h increase the nitrite content released into cell cultured medium,indicating the elevated level of nitric oxide (NO). Peroxynitrite is a powerful modifier of intracellular proteins. The nitration of tyrosine , nitrotyrosine , is a useful marker for detecting peroxynitrite in biological samples.HF cells exposure to SA40-160μM for 4h increase nitrotyrosine level by 10-20﹪,indicating the elevated level of peroxynitrite. Cotreament with 3.2mM Nω-nitro-L-arginine methyl ester ( NAME) and 10μM SA for 4h, the survival rose from 65﹪to 78﹪. These data suggest that NO was involed in SA-induced cell death. HF cells incubated with 40-160μM SA showed glutathione reductase activity significantly decrease to less than 29-60﹪after 2h and less than 43-65﹪after 4h. After HF cells were exposed to 40μM SA for 4h and followed a postincubation in drug-free medium for 12 or 24h. Glutathione reductase(GR) activity rose from 20﹪to 30﹪after 12 and 24 h of recovery. However,GR activity did not recover to the control level wthin 24h. Cotreament of HF cells with SA and NAME（1.6 or 3.2mM） for 4h , partly restore the GR activity. At 1.6mM NAME,the percentage of the recovered GR activity was 4﹪-10﹪.At 3.2mM NAME,the percentage of the recovered GR activity was 4﹪-30﹪. The data showed that treatment with SA increased nitrite production in HF cells and that NAME could not significantly recover GR activity. HF cells exposure to SA40-160μM for 4h decrease GSH level by 16-56nmol /mg protein. This decrease in GSH content was accompanied by a simultaneous increase in GSSG level, with a GSH disappearance and GSSG production.4h after an incubation with 40μM SA, GSSG increase about 2.6-fold.Intracellular total glutathione concentration were almost unchanged suggesting that GSH synthesis did not differ from control cells after 4h. Cotreament with GR and 10μM SA for 4h, the survival rose from 65﹪to 82﹪. These data suggest that decreased glutathione reductase induced by sodium arsenite, lead to cell loss of viability.
25
See-Chang, Huang y 黃錫慶. "Studies on Sodium Arsenite-Induced Mitotic Arrest and Apoptosis in HeLa S3 Cells". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/15932305336275797160.
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博士國防醫學院
生命科學研究所
86
Arsenical compounds, known to be human carcinogens, were shown to disturb cell cycle progression and induce cytogenetic alterations in a variety of cell systems. This report has shown that a 24 h arsenite treatment induced mitotic accumulation in human cell lines. HeLa S3 and KB cells were more susceptible then other cells to mitotic accumulation, i.e., 35% of cell population is arre sted at the mitotic stage in HeLa S3 cells by 5 uM and in KB cells by 10 uM so dium arsenite, respectively. Although arsenite-arrested mitotic cells shared c ommon electrophoretic profiles or kinase activity in 8 mitotic regulatory prot eins with nocodazole arrested mitotic cells, abnormal mitotic figures such as elongated polar distance, enhanced microtubule immunofluorescence and deranged chromosome congression were observed using a microscope. The nocodazole-induc ed spindle disassembly rate was more slowly in arsenite-arrested mitotic cells than those of control mitotic cells. According to turbidity assay, arsenite a t concentrations below 100 uM significantly enhanced initial rate of microtubu le polymerization and its polymer mass. Since spindle dynamics play a crucial role on mitotic progression, these results suggest that arsenite-induced mitot ic arrest may be due to arsenite''s effects on attenuation of spindle dynamics. The survival rates of the detached mitotic HeLa S3 cells harvested from cultu restreated with 5 uM arsenite was 14% and that of the attached cells 97%, sugg esting that the cytotoxicity of arsenite at 5 uM is mainly through mitotic arr est. In fact, when arsenite-arrested mitotic cells were refed with fresh mediu m, an apoptotic process was triggered. By using Percoll density gradient fract ionation to separate apoptotic from non-apoptotic cells, apoptosis was occurre d in those cells with cyclin B degradation but without cell division. Treatmen t of arsenite-arrested mitotic cells with p34cdc2/cyclin B kinase inhibitors, such as staurosporing and 2-aminopurine, resulted in a rapid cyclin B degradat ion and mitotic exit. The interruption of mitotic arrest by enforcing mitotic exit could eliminate cell death but results in polyploidy. These results sugge st that prolonged mitotic arrest may provoke an abnormal mitotic division and finally initiate apoptosis. In addition, overexpression of apoptotic inhibitor , Bcl-2, suppressed arsenite-induced mitotic-mediated apoptosis whereas could not increase colony survival. In the present studies, we have demonstrated tha t arsenite attenuates spindle dynamics and inhibits mitotic exit. The prolonge d mitotic arrest results in cells died of apoptosis. However, the internal or external factors may interrupt mitotic-arrest, enforce mitotic exit and result in polyploidy. Since genomic instacility is known as an essential factor in m ultiple-step tumorigenicity, our results provide a possible clue to understand arsenic carcinogenicity.
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Liu, Fount y 劉芳. "Mechanisms of Cadmium Chloride-,Sodium Arsenite-, and Dimethylarsinic Acid-induced DNA Strand Breaks". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/89917606695265062252.
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碩士國立清華大學
輻射生物研究所
86
Arsenic and cadmium are well-reconized human carcinogens, but their mechanismsare not entirely clear. Recent studies suggested that reactive oxygen species(ROS) and/or reactive nitrogen species (RNS) are involved in the clastogenici-ty of arsenic and cadmium. Since chromosome aberrations mainly come from DNA damage, and DNA damages may require several cellular steps to become chromoso-me aberrations, a more simple question to be asked is: how DNA damages are in-duced by arsenic and cadmium? The aim of this invesgation is to find out whatkinds of ROS and RNS are involved in arsenic- and cadmium-induced DNA strand breaks. DNA strand breaks in sodium arsenite (SA) and cadmium chloride (Cd) treated bovine aortic endothelial cellswere analyzed by single-cell alkaline electrophoresis. The results indicate that inhibitors of nitric oxide syntha-se, Nw- nitro-L-arginine methyl ester (NAME) and S-methyl-L- thiocitrulline (MTC),scavengers of hydroxyl radicals, dimethyl sulfoxide and D-mannitol, could decrease DNA strand breaks in SA- but not in Cd-treated cells. On the contray, catalase, a scavenger of hydrogen peroxide, could decrease DNA strand breaks in Cd- but not in SA-treated cells. However, superoxide dimutase,a scavenger of superoxide, uric acid and Trolox, scavengers of peroxynitrite, could decrea-sse DNA strand breaks breaks in both SA- and in Cd-treated cells. These rsults suggest that SA may induce DNAstrand breaks via nitric oxideand peroxynitrite; and Cd induce DNA strand breaks via superoxide, hydrogenperoxide,and hydroxyl radicals. Moreover, calcium seems to be involved in both SA- and Cd-induced DNA breaks, since calcium chelators, ethylene glycol-bis (beta-ami-ethyl ether)-N, N,N',N'-tetraacetic acid (EGTA), Quin 2, 1,2-Bis(2-aminophe- noxy)ethane-N,N,N',N'-tetra-acetic acid (BAPTA), supressed SA- as well as Cd- induced DNA strand breaks. calcium ionophore, A23187, increased SA- but not Cd-induced comet. Inorganic trivalent arsenic compounds are generally recognized to be more toxic than their metabolite, methylated arsenic compounds. However, SA has recently been shown not to induce DNA strand breaks in human diploid pulmonary epithelial cells, but its metabolite, dimethylarsinic acid (DMA) does. We have compared the induction of DNA strand breaks by SA and DMA in a human embryo lung cell line, MRC-5, and in bovine aortic endothelial cells by single-cell alkaline electrophoresis. The results indicate that SA could induce DNA strand breaks in both cell lines with or wihtout the blockage of DNA repair synthesis by hydroxyurea (Hu) plus cytosine-beta-D-arabinofuranoside (AraC). Whereas, DMA did not induce DNA strand breaks without Hu/AraC. Induction of DNA strand breaks by SA plus Hu/AraC, reached a plateau by 6 h of treatment, wheras, DNA strand breaks induced by DMA plus Hu/AraC contiously increased beyound 10 h. The SA- induced DNA strand breaks were also repaired in a faster rate than that of DMA. Moreover, while the SA-induced DNA strand breaks were mediated by the nitric oxide production and were sensitive to calcium modulation, the DMA-induced DNA strand breaks were insensitive to nitric oxide synthase inhibitors and calcium modulators. These results indicate that SA and DMA induce DNA strand breaks through distinct different mechanisms.
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KE, JUN-LIANG y 柯俊良. "The differential toxicity of sodium arsenite in human fibroblasts and Chinese hamster ovary cells". Thesis, 1988. http://ndltd.ncl.edu.tw/handle/56601357234275968044.
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Lin, Yii-Ling y 林依玲. "Modulation of Human Cancer Cell Lines to Mitomycin C Susceptibility by Sodium Arsenite Pretreatment". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/18958801450118713256.
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碩士國立陽明大學
藥理學研究所
91
Arsenic has been extensively used in medicine for a long time. In recent years, therapy with arsenic trioxide offers the opportunity for a complete remission and improved survival in patients with refractory or relapsed acute promyelocytic leukemia (APL). However, therapy with arsenic in sold tumors is still on clinical trials. Mechanisms of arsenic action in cancer therapy include induction of cytodifferentiation, apoptosis, and inhibition of cell proliferation and angiogenesis, etc. The objective of this study attempts to find suitable target genes altered by arsenic and to establish an effective cancer therapy protocol for other cancers. In a preliminary cDNA microarray study in our laboratory, NAD(P)H quinone oxidoreductase 1 (NQO1), glutathione peroxidase 2 (GPX2) and heme oxygenase-1 (HO-1) were induced in human lung adenocarcinoma CL3 cells treated with 2 μM sodium arsenite for 24h. In the present study, the enhanced mRNA expression of these genes was further confirmed by Western blot assay. Among these genes, increased protein level and enzyme activity of NQO1 were confirmed by western blot technique and enzymatic activity assay. Since NQO1 is a quinone reductase that physiologically plays an important role on quinone drug metabolism, the influences of the quinone compounds’ cytotoxicity by arsenite via enhanced NQO1 expression were examined by colony forming assay in CL3 cells. Among quinone drugs tested, sodium arsenite pretreatment resulted in increased susceptibility of mitomycin C to CL3 cells but had no obvious influence on susceptibility of adriamycin, menadione and mitoxantrone. Furthermore, dicumarol, a specific inhibitor of NQO1, was shown to abrogate the increased susceptibility of CL3 cells to mitomycin C by arsenite. These results demonstrated the involvement of NQO1 in increased susceptibility to mitomycin C by arsenite pretreatment. To investigate the therapeutic potential of arsenite pretreatment in different cell types, the present results demonstrated that arsenite pretreatment resulted in increased NQO1 activity and susceptibility to mitomycin C in human lung large cell carcinoma H1299 cells and human uroepithelium MC-SV-HUC-1 cells. In contrast, arsenite pretreatment showed neither enhancement of NQO1 expression nor susceptibility to mitomycin C in human lung large cell carcinoma H460 cells. These results revealed that the therapeutic effectiveness of combination of arsenite and mitomycin C in cancer cells that NQO1 expression is enhanced by arsenite pretreatment warrants further animal and clinical trials in the future.
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Fan, Chih-Chun y 范智鈞. "Protein kinase C involved in low dose sodium arsenite-mediated heme oxygenase-1 expression". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/02034672769441583839.
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碩士國立中央大學
生命科學研究所
88
Sodium arsenite is a well-known carcinogen and may cause cardiovascular disease, such as atherosclerosis and blackfoot disease. Heme oxygenase-1 (HO-1) is an inducible enzyme that catalyzes heme degradation into iron, biliverdin, and carbon monoxide. HO-1 is induced by a variety of agents, such as heme, oxidative stress, heat shock, UV irradiation, and some heavy metals (arsenite and cadmium). HO-1 has been proposed to play a dual role in protecting cells against or stimulating intracellular oxidative injury. We investigated the induction of HO-1 by low doses of sodium arsenite (< 1 micro mol/L) in bovine aortic endothelial cells (BAEC). Our results show that both HO-1 protein and mRNA are significantly induced by treatment of BAEC cells with 1mM sodium arsenite. To examine which pathway or which signaling molecule is involved in low dose sodium arsenite-mediated induction of HO-1, several enzyme inhibitors were adopted in this study. Among these inhibitors, protein kinase C (PKC) inhibitors such as H7, staurosporine, and chelerythrine chloride decreased 1 mM sodium arsenite-induced HO-1 expression, whereas inhibitors of tyrosine kinase, nitric oxide synthase (NOS), extracellular-regulated kinase (ERK), and PI-3 kinase are unable to inhibit HO-1 induction. Furthermore, the translocation of various PKC isoforms is then examined by histoimmunochemical technique. The present results have shown that PKC-eta and PKC-epsilon are apparently translocated from cytosol to membrane after 1 micro mol/L sodium arsenite treatment. Therefore PKC-eta and PKC-epsilon is probably involved in low dose sodium arsenite-indued HO-1 expression in BAEC.
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Tseng, Belly y 曾蓓莉. "The study on sodium arsenite-induced expression of glutathione peroxidase activity in human fibroblast". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/29665865265894719035.
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碩士國立清華大學
生命科學系
88
Sodium arsenite (SA), a well defined carcinogen, will cause various cell damages but the exactly mechanism remains unknown. In this study, sodium arsenite decreased the activity of glutathione peroxidase and survival fraction in human fibroblasts (HF). Survival fraction of HF was 50 % while the cells were treated with 40 mM sodium arsenite for 4 h. Under the same SA, the antioxidant Gpx activity in HF was no difference comparing to control cells, while catalase activity was increased 1.1-fold of control. Immediately after cotreatment with 40 mM sodium arsenite and 2 mM 3-aminotriazole (3-AT, inhibitor of catalase), Gpx activity in HF was increased 30 % than those cells after 4 h treatment with 40 mM SA alone. This indicated that Gpx function was partially replaced by catalase. Cells in same SA treatment and time with or without 3-AT co-treatment following a postincubation in drug-free medium for 12 h had 30 % higher Gpx activity than those from cells without any treatment. However, HF after (a) SA treatment or (b) SA plus 3-AT treatment in similar protocol following a postincubation in drug-free medium for 24 h had only (a) 70 % or (b) 80 % Gpx activity of those from control cells, respectively. On the other hand, glutathione (GSH) content in cells responded to 4 h treatment with 40 mM SA and followed in drug-free medium for 12 h was significantly elevated form those of control cells. GSH content returned to normal level as control in similar SA-treated cells following a postincubation in drug-free medium for 24 h. These different Gpx activity and GSH content in SA-treated HF following 12 or 24 h postincubation may be resulted from the disturbance of regular cell cycle progression in cells after SA treatment, or from the production of reactive oxygen species in cells even after the removal of SA treatment. However, it required more experimental evidences to support. In the presence or absence of 2 mM 3-AT, gpx mRNA expression in HF after 40 mM SA for 4 h was increased about 40 % of those in control cells. Gpx mRNA in HF after 40 mM SA treatment for 4 h and followed a postincubation in drug-free medium for 12 or 24 h was only 70 % or 80 % of those in control cells. Treatment with 100 mM DL-buthionine-[S,R]-sulfoximine (BSO) for 4 h decrease glutathione (GSH) content in HF. Co-treatment cells with 100 mM BSO and 40 mM SA for 4 h would decrease SRB detected survival fraction to 25 % of those from untreated cells. Without BSO treatment, a 50 % survival fraction was resulted in cells after 40 mM SA treatment in the presence or absence of 2 mM 3-AT for 4 h. It was suggested that Gpx might play more important role than catalase to protect cells during SA treatment. Treatment of 40 mM SA in cells for 4 h apparently increased (about 2-fold of that in control sample) the nitrite content released in cell cultured medium, indicating the elevated level of NO. In addition, cells immediately after cotreatment with 3.2 mM NO inhibitor, Nw-nitro-L-arginine methyl ester (NAME), and 40 mM SA, the released nitrite in cultured medium was reduced to the level of control cells. Under the same treatment, Gpx from SA and NAME co-treated cells increased 20 % of those from control. These indicated that the change of Gpx activity in cells after SA treatment may be mediated from the SA-induced NO formation, causing reducing Gpx activity.
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SHEN, YING-CAI y 沈英才. "Pretreatment with sodium arsenite enhances the cytotoxicity of cisplatin-treated human cervical carcinoma cells". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/77198804862886058859.
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HU, MENG-CHUN y 胡孟春. "Sodium arsenite enhances the cytotoxicity of ultraviolet light and methyl methanesulfonate through different mechanisms". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/90311907236871325034.
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Liao, Yi-Chun y 廖翊君. "Interaction of sodium arsenite and H-Ras oncogene on carcinogenesis of human urothelial cells". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/21396448915230136409.
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博士國立陽明大學
藥理學研究所
102
Inorganic arsenite (iAs) is a human carcinogen. Numerous studies have shown that mutation-activated H-Ras is frequently observed in human urothelial carcinomas. The interaction between iAs, an environmental factor, and H-Ras, an oncogene, is not clear. To explore the effect of iAs and H-Ras on genotoxic and tumorigenesis effects, the experiments were conducted to establish the human urothelial cells stable ectopically expressing H-RasG12V, an activated H-Ras oncogene, as a platform to understand these interaction. The present results showed that H-RasG12V-transformed human urothelial cells (HUC-RAS) were more susceptible to arsenite-induced cell death, DNA damage, micronuclei (MN) formation and anchorage-independent growth than control cells (HUC-neo). Furthermore, iAs treatment induced higher intracellular levels of reactive oxygen species (ROS) in the HUC-RAS cells than in the HUC-neo cells. N-acetyl-L-cysteine, an antioxidant, could suppress the iAs-induced increases in ROS and genetic damage. This study further demonstrated that the intracellular glutathione levels were significantly elevated by the iAs treatment of the HUC-neo cells but that this effect was not observed in the HUC-RAS cells. The iAs treatment also induced higher superoxide dismutase activity in the HUC-neo cells than in the HUC-RAS cells. Alternatively, catalase activity was higher in the HUC-RAS cells than in the HUC-neo cells, but this enzyme was significantly suppressed by iAs. Moreover, iAs activated the ERK and JNK signaling pathways, which are involved in iAs-induced ROS production and genetic damage. These results suggest that elevated catalase activity in H-RasG12V-transformed cells is significantly suppressed by iAs via activation of ERK and JNK signaling pathways and hence attenuate the defense of H-RasG12V-transformed cells against iAs-induced oxidative injuries. In order to further clarify the interaction of iAs and H-Ras, the HUC-neo and HUC-RAS cells were continuously grown in the absence or presence of iAs at 0.5 μM for 30 passages and designated as to P0N, P0NA, R0R and P0RA, respectively. Of the sublines derived from subcutaneously tumor xenograft, P1R, P1RA, P2R and P2RA sublines were established. By using Illumina HumanHT-12 Expression BeadChip Whole Genome arrays cDNA analysis, 878 genes were differentially expressed among these sublines. IPA-ranked signaling networks of diseases and functions identified altered the metastasis, cell movement, migration of cells and inflammatory response signaling networks. It's worth noting that among these differentially expressed of inflammatory-related gene IL1α, IL1β, IL6 and IL8, were up-regulated in the sublines derived from iAs exposed cells as compared with those without chronic exposure to iAs. In aspects of ability to tumors formation, the P0RA sublines growth slower than P0R sublines on subcutaneously tumor xenograft, but P1RA sublines have more tumorigenic ability than P1R sublines. In this model, liver of nude mice derived from P0RA cells, and P1RA sublines have develop the necrosis phenomena and inflammation cells accumulation around the blood vessels, but not from P0R cells and P1R sublines. In addition, the data also demonstrated P2R and P2RA sublines obvious promote the lung metastasis in the NOD-SCID mouse by tail vein injection. Altogether, this study provides evidence for exposure of iAs modulates the tumorigenesis of H-Ras transformed human urothelial cells. However, further research is needed to explore the complex mechanisms. Further studies will be needed to clarify how long term exposure of iAs can induce the expression of inflammatory-related gene in cancer cells. These data may be valuable for further understanding in molecular mechanism of arsenic carcinogenicity.
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Chen, Ting-Ting y 陳婷婷. "The Cytotoxic Effects of X-ray, Cisplatin and Sodium Arsenite in E7/neo-transfected Cells". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/24mp88.
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碩士國立清華大學
生物科技研究所
92
Abstract Most human cervical cancers are caused by human papilloma virus (HPVs) infection. The HPV-E7 protein of HPV can bind to retinoblastoma protein (Rb) then inhibits the cell cycle regulation activity of Rb protein. Previous study of this lab showed that sodium arsenite (SA) could restore p53 tumor suppressor pathway in human cervical carcinoma SiHa cells, but not mutant-p53-SiHa (SiHa-p53m) cells. In present study showed that cisplatin could restore p53 expression in HPV-16 E6 containing SiHa cells after 10 mM cisplatin treatment for more than 4 hours (4 h) and enhance the radiosensitivity (in sub-G1 apoptosis) in HPV16 E6 containing SiHa cells, but not SiHa-p53m cells. Whether E7 involving in SA or cisplatin restored p53 function or cisplatin enhanced radiosensitivity (X-ray) in E6/E7 containing SiHa cells was not yet known. In order to determine E7 function in SiHa cells after treat with SA, cisplatin or X-ray, SiHa and human fibroblast (HF) cells were transfected with the retrovirus-derived vector pLXSN containing both the neo and HPV-16 E7 gene. Four individual clones (SiHa-E7#4, SiHa-E7#8, SiHa-E7#14 and HF-E7#8) were selected because of their high level of E7 protein and hypo-phosphorylated Rb protein (pRb) among a total of 30 (15 SiHa-E7; 15 HF-E7) G418-resistant transfected clones. Most E7 protein were located in the nucleus of SiHa and SiHa-E7#14 cells after immuno-fluorescence stain, but some E7 protein were found in cytoplasm surrounding the nucleus. Compared to parental SiHa cells, the SiHa-E7#14 cells have 1-3 fold more pRb protein, but less p53 and p21 protein. In HF-E7#8 cells, the E7 protein increased 3-6 fold of p53 expression than parental HF cells. The E7 effects on sub-G1 apoptosis and cytotoxicity were assayed by means of Flow-Cytometry (A) and SRB assay (B) in E7-transfected cells and parental cells. SiHa-E7#14 and HF-E7#8 cells both induced 1-3 fold sub-G1 apoptosis than parental cells after 0-8 Gy X-ray treatments. They also have 1-3 fold more sub-G1 apoptosis than parental cells after 0-5 μM cisplatin treatment for 24 h. SiHa-E7 #14 and HF-E7 #8 cells both appeared to have a 1.5-2 fold SRB-cytotoxicity than parental cells after the same dose of X-ray or cisplatin treatment. After 0-32 μM SA treatment for 24 h, SiHa and SiHa-E7#14 cells showed no significant difference in cytotoxic results from protocol (A) and (B). These results confirmed the previous study of this lab: SA induced SiHa cells’ apoptosis via decreasing E6 gene expression and then restoring p53 protein function. E7 protein had no significant effects on SA-induced apoptosis. In contrast HF-E7#8 cells induced more sub-G1 apoptosis than parental HF cells after the same dose of SA for 24 h treatment. Western blotting indicated that an increase in dose-dependent p53 and pRb protein expression (according to X-ray 0-8 Gy or cisplatin 0-10 μM for 24 h) was found in SiHa and SiHa-E7 #14 cells. In the other hand p21, p53 down stream protein, expression was a decreased in dose-dependent. The results from the above treatment showed that, active-caspase-3 protein in two kinds of SiHa cells were no different before or after treatment. P53 protein increased in both cells with agent doses in HF cells, but p53 expression level showed no difference in HF-E7#8 cells. In this study, E7 gene was successfully transfected into SiHa and HF cells stably. Flow-cytometry and SRB assay showed that, E7 protein had no significant effect on SA-induced apoptosis, but increased the sensitivity of SiHa cells to cisplatin and X-ray. The E7 protein may through binding pRb protein and decreasing p21 protein expression to increase cells undergoing apoptosis.
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Chien-Wei y 黃千維. "The Differential Effects of Sodium Arsenite, Cigarette Smoke Extract, and Methylglyoxal on Oxidative DNA Damage". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/11753347551063896869.
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碩士中山醫學大學
生物醫學科學學系碩士班
99
OGG1 is the main base excision repair protein that removes 8-oxodG from DNA. Previous studies have shown that sodium arsenite (As3+), cigarette smoke extract (CSE), and methylglyoxal (MG) can significantly induced DNA damage, including 8-oxodG in different human cell lines. And, the intracellular reactive oxygen species (ROS) generation is mainly responsible for their induction of 8-oxodG. However, the suppression of OGG1 expression or activity by As3+, CSE and MG treatments are still unknown. Therefore, the purpose of this study was to determine the possible deleterious effects of As3+, MG and CSE on gene expression and enzyme activity of OGG1. The expression level and enzyme activity of OGG1 protein were detected by Western blot and endonuclease activity assay, respectively. The levels of intracellular ROS and 8-oxodG of As3+, CSE and MG-treated cells were also detected by DCHF-DA assay using a multi-well fluorescence plate reader and immunofluorescence staining. The results showed that none of As3+ (0.1 – 1000 µM), CSE (5% – 25%) and H2O2 (1 – 15 mM) could inhibit directly the enzyme activities of FPG and hOGG1 in vitro. Surprisingly, MG (0.5 – 4 mM) could potently inhibit the enzyme activity of FPG with a dose-dependent manner (P<0.05), but it did not influence the emzyme activity of hOGG1. Interestingly, thiol antioxidants (NAC and GSH) (0.2 – 5 mM) and Cu2+ (1 – 1000 µM) also significantly inhibited the enzyme activity of both FPG and hOGG1 (P<0.01), but GSSG (0.2 – 5 mM) did not affect the FPG and hOGG1 activities. ECV304 cells treatment with As3+ (0.25 – 10 µM) could increase intracellular ROS levels. After treatment with 5 and 10 µM As3+, nuclear 8-oxodG levels were increased (P<0.05). In addition, there was a slight increase (P<0.05) in the intracellular OGG1/2 protein expression. However, it could neither induce ROS nor reduce OGG1/2 protein expression (P<0.01) after ECV304 was treated with CSE (5% - 25%) for 24 hours. Taken together, these results suggest that As3+-induced 8-oxodG formation may not be caused by a direct inhibition of hOGG1 activity but through its effect of increasing the level of ROS in ECV304 cells. In vitro, the activity of purified Fpg and hOGG1 proteins inhibited by thiol containing compounds (GSH and NAC) also suggests that cellular GSH may be involved in the regulation of the DNA repair enzyme hOGG1 in human cells.
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Khamis, Imran. "Effect of combined sodium arsenite and cadmium chloride treatment on heat shock protein gene expression in Xenopus laevis A6 kidney epithelial cells". Thesis, 2013. http://hdl.handle.net/10012/7916.
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Sodium arsenite and cadmium chloride are two widespread environmental toxicants which have deleterious effects on living organisms. At the cellular level, sodium arsenite and cadmium chloride cause oxidative stress, dysregulation of gene expression, apoptosis, and the unfolding of protein. Furthermore, both chemical stressors individually have the ability to induce heat shock protein (HSP) accumulation. HSPs are molecular chaperones that aid in protein folding, translocation and in preventing stress-induced protein aggregation. Previously, our laboratory demonstrated that treatment of A6 kidney epithelial cells of the frog Xenopus laevis, with either cadmium chloride or sodium arsenite plus a concurrent mild heat shock resulted in an enhanced accumulation of HSPs that was greater than found with the sum of the individual stressors. To the best of our knowledge, no information is available to date on the effect that these two chemical stressors have in combination on HSP accumulation in aquatic organisms. The present study examined the effect of simultaneous sodium arsenite and cadmium chloride treatment on the pattern of HSP30 and HSP70 accumulation in Xenopus A6 cells. Immunoblot analysis revealed that the relative levels of HSP30 and HSP70 accumulation in A6 cells treated concurrently with sodium arsenite and cadmium chloride for 12 h were significantly higher than the sum of HSP30 or HSP70 accumulation from cells subjected to the treatments individually. For instance, the combined 10 µM sodium arsenite plus 100 µM cadmium chloride treatment resulted in a 3.5 fold increase in HSP30 accumulation and a 2.5 fold increase in HSP70 accumulation compared to the sum of the stressors individually. This finding suggested a synergistic action between the two stressors. Pretreatment of cells with KNK437, an HSF1 inhibitor, inhibited the combined sodium arsenite- and cadmium chloride-induced accumulation of HSP30 and HSP70 suggesting that this accumulation of HSPs may be regulated, at least in part, at the level of transcription. Immunocytochemical analysis employing the use of laser scanning confocal microscopy (LSCM) revealed that simultaneous treatment of cells with the two stressors induced HSP30 accumulation primarily in the cytoplasm in a punctate pattern with some dysregulation of F-actin structure. Increased ubiquitinated protein accumulation was observed with combined 10 µM sodium arsenite and 10, 50 or 100 µM cadmium chloride treatment compared to individual stressors suggesting an impairment of the ubiquitin-proteasome degradation system. Finally, while incubation of A6 cells with 1 µM sodium arsenite plus 10 µM cadmium chloride did not induce a detectable accumulation of HSPs, the addition of a 30 °C mild heat shock resulted in a strong accumulation of HSP30 and HSP70. This study has demonstrated that concurrent sodium arsenite and cadmium chloride treatment can enhance HSP accumulation. Since HSP accumulation is triggered by proteotoxic stress, these findings are relevant given the fact that aquatic amphibians in their natural habitat may be exposed to multiple chemical stressors simultaneously.
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Ju-Pi, Li. "Investigation of roles of mitogen-activated protein kinases in cellular damage responses elicited by sodium arsenite". 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0016-0109200613402611.
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LIU, WEN-XI y 劉文熙. "Effects of sodium arsenite on DNA repair induced by ultraviolet light in hela S-3 cells". Thesis, 1989. http://ndltd.ncl.edu.tw/handle/28537487494230649213.
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Ai-Hsuan y 林艾璇. "Effect of sodium arsenite induced carbonylation on Enolase and Fascin in human umbilical vein endothelial cells". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/22529468497672054326.
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碩士中山醫學大學
營養學研究所
94
The pollution of drinking water make people expose to the inorganic arsenic and cause the chronic arsenic poisoning. Many epidemiologic studies have demonstrated that the chronic arsenic exposure associated with the increasing of chronic diseases. Exposure of arsenic would induce ROS overload and result in protein oxidation. In this study, we examined the arsenite induced protein carbonylation and the functional effects of carbonylated proteins in human umbilical vein endothelial cells (HUVECs). By two-dimensional gel electrophoresis and matrix assist laser desorption ionization time of flight mass spectrometery(MALDI-TOF/MS) analyzed methods, three of arsenic-sensitive carbonylated proteins were identified to be the α-Enolase、Fascin and Vimentin. We further examined α-Enolase by enzyme activity assay. The results showed that arsenite decreased the Enolase activity in dose-dependent. In addition, we also observed that the arsenite would disturb the F-actin filament by carbonylation of Fascin. As these results, we suggested that the protein which was modified by arsenite would lead to protein carbonylation and further to effect physiological state of cells.
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Li, Ju-Pi y 李如璧. "Investigation of roles of mitogen-activated protein kinases in cellular damage responses elicited by sodium arsenite". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/49519734679384580022.
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博士國立清華大學
生命科學系
94
Arsenic, a widely distributed natural toxicant, is highly associated with increased risk for human cancers of the lung, skin, bladder, and other internal organs. Arsenic carcinogenicity has been associated with its ability to cause genomic injury, inhibit DNA repair processes, perturb cell cycle progression, and impede cell division. Many signal transduction pathways are quickly activated upon exposing mammalian cells to arsenic, however, the mechanism that appropriate cellular responses regulated by these activated signals remains to be elucidated. In this thesis, we investigated whether mitogen-activated protein kinases (MAPKs) serves as a part of the cellular damage-response network to regulate cell cycle progression, nucleotide excision repair (NER), cytotoxicity, and genotoxicity in arsenite-treated human cells. We began to explore the ability of sodium arsenite in activating three members of MAPKs, i.e., ERK, JNK, and p38, and their cross-talks and cellular effects in asynchronous CL3 human non-small-cell lung carcinoma cells. Arsenite at doses causing ~60% cytotoxicity (50 mM, 3 h) activated sustained-ERK, -JNK, and -p38, inhibited NER-repair synthesis, and induced micronucleus formation. Upon arsenite exposure, suppression of ERK activation further enhanced JNK activity; conversely, forced expression of MKK1-ERK attenuated JNK activity. Inhibition of JNK or p38 did not affect the ability of arsenite to elicit the other two MAPKs. The results suggest that ERK down-regulates JNK activation, while p38 does not crosstalk with ERK and JNK in arsenite-treated cells. Suppression of ERK activation enhanced arsenite cytotoxicity. Inhibition of JNK did not affect arsenite cytotoxicity, yet co-inhibition of ERK and JNK synergistically enhanced it. Conversely, suppression of p38 reduced arsenite cytotoxicity. Suppression of either ERK or p38, but not JNK, decreased arsenite-induced micronucleus formation. Intriguingly, suppression of ERK activation rescued the NER synthesis inhibition after arsenite, while suppression of JNK or p38 could not. Forced expression of MKK1-ERK markedly elevated the endogenous NER synthesis, which could be suppressed by arsenite. However, the arsenite-elicited NER inhibition was recovered by reinforcing the MKK1-ERK signal. The results suggest that ERK signal exhibits dual roles in regulating NER synthesis. Thus, under arsenite exposure of exponential growing CL3 cells, p38 activation contributed to genomic instability and cell death, ERK activation played a part in NER synthesis inhibition, genomic instability, and survival, and JNK synergistically contributed to ERK-mediated survival.Furthermore, we found that G1 was the most insensitive phase to arsenite cytotoxicity, yet it was highly susceptible to arsenite in NER synthesis inhibition, micronucleus induction, and the activation of sustained-ERK and -p38 signals. In the arsenite-treated G1-enriched cells, suppression of ERK activation further enhanced cytotoxicity, yet recovered NER synthesis activity and lowered the micronucleus induction. In contrast, suppression of p38 did not show such effects on the arsenite-induced cytotoxicity and micronucleus induction. Arsenite (50 mM, 3 h) delayed the progression of G1-enriched cells for at least 12 h, partly via down-regulation of cyclin D1, cyclin E, and cyclin A protein levels, and Cdk4-, cyclin E-, cyclin A-, and Cdk2-associated kinase activities. Moreover, arsenite efficiently decreased Skp2, an activating subunit of the SCF ubiquitin ligase, and increased p21Cip1 and p27Kip1 protein levels in G1-enriched CL3 cells. Suppression of ERK activation further enhanced the G1 delay and sub-G1 populations and the decrease in cyclin D1 protein and cyclin D1-associated kinase activity. Thus, after arsenite exposure of the G1-enriched cells the sustained-ERK signal counteracted apoptosis and participated in recovery from the G1 delay via increase in cyclin D1 re-synthesis, yet the signal also mediated in NER inhibition and micronucleus formation, which may lead to carcinogenesis. We next explored whether arsenite induces the G2-checkpoint responses and roles of the activated-ERK and -p38 signals. Using the aphidicolin protocol, CL3 cells were synchronized in early-G2 and late-G2 phases. Exposing the early-G2 cells to arsenite markedly retarded the G2 progression, and decreased cyclin B1 protein level and Cdk1 kinase activity. In contrast, cyclin B1 protein level was accumulated in arsenite-treated late-G2 cells, indicating cyclin B1 exhibits distinct cell cycle-dependent sensitivity to arsenite. Cyclin B1 was polyubiquitinated and subsequently degraded via 26S proteasome in arsenite-treated early-G2 cells, which was accompanied by activation of p38 and ERK. Under arsenite, knockdown p38a expression or inhibiting p38 activation lowered the cyclin B1 ubiquitination/degradation and rescued the Cdk1 kinase activity, while forced expression of MKK3/6-p38 exhibited opposing effects. Inactivation of p38 allowed G2-to-M progression, reduced sub-G1 population, and increased cell viability in the arsenite-treated early-G2 cells. By contrast, blockage of ERK activation though did not affect the G2 delay and cyclin B1 proteolysis, markedly enhanced sub-G1 population and decreased cell viability caused by arsenite. Inactivation of either p38 or ERK in early-G2 cells decreased the arsenite-induced micronucleus. Together, the results suggest that under arsenite p38 triggers cyclin B1 degradation and connects G2 arrest and apoptosis, while ERK contributes to survival; yet, both signals may confer genomic instability. The findings obtained in this thesis have provided evidence to indicate that each MAPKs plays distinct roles in cellular damage responses after arsenite, which would contribute to carcinogenesis.
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黎雁行. "Studies of the Enhancement of Sodium Arsenite on Ioning Radiation-Induced Cytotoxicity in Human Cervical Cancer Cells". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/51485511291644295114.
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碩士國立清華大學
生命科學系
90
Numerous epidemiological studies suggest that sodium arsenite (SA) is a carcinogen. However, recent data have renewed the interest in its anti-carcinogenic properties. More than 90﹪of cervical cancer cells contain oncogenic human papillomaviruses (HPV). These cells usually possess wild-type p53 alleles, but its function is abrogated by HPV E6 oncoprotein through the ubiquitin pathway. Sodium arsenite had been shown to suppress HPV-16 E6 gene, induce p53 tumor suppressor pathway and enhanced apoptosis in E6-transfected lymphoblastoid cells. Additionally, E6-transfected TK6 cells were more sensitive to SA, but more resistant to IR than parental TK6 cells. In the present study, HPV-positive SiHa cervical cancer cells were treated with SA to examine p53 tumor suppressor pathway and apoptotic responses. After treatment with SA, it was found that SA could restore the expression of p53 and its downstream genes, p21 and mdm2, in SiHa cells in dose and time dependent manner. It was also shown that apoptosis occurred in SiHa cells through flow cytometric analysis, DNA fragmentation assay and apoptotic cells staining. In contrast to SA, X-irradiation could not restore p53 tumor suppressor pathway in SiHa cells. Pretreatment with SA could restore p53 function and enhance X-ray-induced cytotoxicity in SiHa cells. However, X-ray-induced cytotoxicity was not reduced by expression of a pCDNA3-p53m（containing mutated p53 at R273H） plasmid. Results from this study suggest that SA may serve as a radiosensitizer for X-ray therapeutic purpose in HPV-positive cancer cells. Therefore, further evidence is required to explore the relationship between SA-restored p53 expression and SA-enhanced radiosensitivity in SiHa cells.
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Chou, Ruey-Hwang y 鄒瑞煌. "The Cytotoxic Effects of Sodium Arsenite in Human Papillomaviruses E6 and E7 Oncogenes -Containing Human Cancer Cells". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/87722863907569114648.
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博士國立清華大學
生命科學系
90
Arsenic compounds are common, naturally occurring substances. They have been reported to be human carcinogens associated with malignancies of the lung, bladder, skin, liver, kidney, and prostate. However, arsenic compounds have been used as therapeutic agents for more than 2,400 years. Recently, arsenic trioxide (As2O3) was wildly used to cure acute promyelocytic leukemia (APL). The Food and Drug Administration (FDA) of the USA has approved arsenic trioxide for the treatment of APL in September 2000. Cervical cancer is the second leading cause of death from cancer in women worldwide. Over 90% of human cervical cancer cells are infected with different types of human papillomaviruses (HPVs) and possess wild type p53 and Rb tumor suppressor genes. But in these cells, normal p53 and Rb functions are abolished by HPVs E6 and E7 oncogenes, respectively. Therefore, restoration of p53 or Rb function by blocking E6/p53 or E7/Rb pathway might be a potential therapeutic purpose for these cancer cells. In the present study, we investigated the effects of sodium arsenite (SA) on HPVs E6 and E7 oncogenes, the effects of SA on apoptotic responses, and try to promote SA as a potential therapeutic agent for HPV-positive cancer cells. Two systems were used in this study: (1) the human lymphoblastoid cells (TK6 cells), and their E6-transfectants (TK6-E6 cells), (2) the human cervical carcinoma cells originally infected with HPV-16 (SiHa cells). Treatment with SA, but not X-ray, decreased the E6 mRNA levels and induced the expressions of p53, and its down stream genes, p21, and mdm2 in TK6-E6 cells. SA enhanced apoptotic responses, including more sub-G1 percentages, more activated caspase-3 fragments (17 kD), and more DNA ladder in TK6-E6 cells than these in their parental TK6 cells. According to the results from MTT assay, TK6-E6 cells were more sensitive to SA, but more resistant to ionizing radiation (IR) than TK6 cells. It implied that instead of IR, SA could be a potential therapeutic agent for E6-possitive cancer cells. In human cervical cancer cells, SA down-regulated E6 and E7 mRNA levels, restored p53 tumor suppressor pathway, and induced Rb expression. While SA restored normal p53 function, G2/M arrest in the cell cycle progression and apoptosis occurred. Transfection of a dominant-negative p53 markedly reduced the SA-induced apoptosis, indicating that p53 mediated SA-induced apoptosis in SiHa cells. Besides p53, other molecules are involved in regulation of apoptosis. Cyclic AMP-dependent protein kinase A (PKA) has been reported to inhibit E6 function by phosphorylation of threonine residue at its C-terminal region, which is not involved in p53 binding and degradation. But, E6 binds to Bak, an apoptosis inducer, at this region. In this study, I investigated the roles of PKA in regulation of SA-induced apoptosis. Pretreatment with a PKA inhibitor, HA1004, significantly reduced the SA-induced apoptotic cell death in E6-positive SiHa and TK6-E6 cells, but not in E6-negative TK6 cells. It implied that PKA played some roles in regulation of E6 function, which was involved in SA-induced apoptosis, in E6-positive cancer cells. Furthermore, pretreatment with HA1004 decreased SA-induced Bak expression only in E6-possitive cancer cells. However, HA1004 did not affect SA-induced p53 expression in both E6-positive and E6-negative cancer cells. These results suggested that PKA inhibited E6 degrading SA-induced Bak, and resulted in apoptotic cell death in E6-positive cancer cells, but PKA could not inhibit the E6 function of degradation of SA-induced p53. Base on these above results, SA-induced apoptotic cell death in HPV-positive cancer cells might result from the following: (1) down regulation of E6 and E7 oncogenes, (2) restoration of the p53 tumor suppressor pathway, and (3) at least in part, involvement of PKA in inhibition of Bak degradation by E6.
43
Yan-Cho, Lee y 李元晫. "Detection of genomic DNA alternations in sodium arsenite-treated lymphoblastoid cells by random amplified polymorphic DNA assay". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/35075218998894624845.
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碩士東海大學
生物學系
92
Abstract Epidemiologic studies demonstrated that long-term exposure to arsenic induces many human diseases, including blackfoot disease, atherosclerosis, and cancers. Although evidences show an association between arsenic and cancer, the molecular mechanism is still unclear. It is widely accepted that cancer results from the accumulation of mutations in the genes. Sodium arsenite has been shown to induce oxidative DNA damages and DNA-protein crosslinks. In this study, we used the random amplified polymorphic DNA (RAPD) assay with ninety arbitrary primers to evaluate the effects on the genomic DNA of human lymphoblastoid cells exposed to sodium arsenite. The main changes in RAPD profiles following sodium arsenite treatments were a decrease and an increase in band intensity. Two RAPD primers (D11 and F1) were more discriminated the RAPD profiles between sodium arsenite-treated and control genomic DNA. The sequences of these loci amplified with primers D11 and F1 showed highly similar to human RB1CC1 and PACE4 genes. The DNA markers were purified for the molecular detection of sodium arsenite-induced DNA damage by nucleic acid hybridization. To confirm the effect of sodium arsenite on RB1CC1 and PACE4 genes, we examined the expression of these two genes by Northern blot and RT-PCR analysis. Sodium arsenite treatment could significantly up-regulate the expression of RB1CC1 in human lymphoblastoid cells. Taken together, our results demonstrated, for the first time, that RAPD is a good tool for the detection of genomic DNA alternations and direct screening of new molecular markers related to sodium arsenite-induced carcinogenesis
44
Young, Jordan T. F. "Analysis of heat shock-, sodium arsenite- and proteasome inhibitor-induced heat shock protein gene expression in Xenopus laevis". Thesis, 2009. http://hdl.handle.net/10012/4383.
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Previous studies have focused on the effect of individual stressors on hsp gene expression in eukaryotic organisms. In the present study, I examined the effect of concurrent low doses of sodium arsenite and mild heat shock temperatures on the expression of hsp30 and hsp70 genes in Xenopus laevis A6 kidney epithelial cells. Northern hybridization and western blot analysis revealed that exposure of A6 cells to 1-10 μM sodium arsenite at a mild heat shock temperature of 30˚C enhanced hsp30 and hsp70 gene expression to a much greater extent than found with either stress individually. In cells treated simultaneously with 10 μM sodium arsenite and different heat shock temperatures, enhanced accumulation of HSP30 and HSP70 protein was first detected at 26˚C with larger responses at 28 and 30 ˚C. HSF1 activity was involved in combined stress-induced hsp gene expression since the HSF1 activation inhibitor, KNK437, inhibited HSP30 and HSP70 accumulation. Immunocytochemical analysis revealed that HSP30 was present in a granular pattern primarily in the cytoplasm in cells treated simultaneously with both stresses. Finally, prior exposure of A6 cells to concurrent sodium arsenite (10 μM ) and heat shock (30 ˚C) treatment conferred thermotolerance since it protected them against a subsequent thermal challenge at 37 ˚C. Acquired thermotolerance was not observed with cells treated with the two mild stresses individually. It is likely that the enhanced accumulation of HSPs under these conditions permits the organism to cope with multiple environmental stresses encountered in their natural aquatic habitat.
Previous studies have shown that inhibiting the activity of the proteasome also leads to the accumulation of damaged or unfolded proteins within the cell. In the second phase of this study, I report that inhibition of proteasome activity by the inhibitors carbobenzoxy-L-leucyl-L-leucyl-L-leucinal (MG132) and lactacystin induced the accumulation of HSP30 and HSP70 as well as their respective mRNAs. The accumulation of HSP30 and HSP70 in A6 cells recovering from MG132 exposure was still relatively high 24 h after treatment and it decreased substantially after 48 h. Exposing A6 cells to simultaneous MG132 and mild heat shock enhanced the accumulation of HSP30 and HSP70 to a much greater extent than with each stressor alone. HSP30 localization in A6 cells was primarily in the cytoplasm as revealed by immunocytochemistry. In some A6 cells treated with higher concentrations of MG132 and lactacystin, HSP30 was also found to localize in relatively large cytoplasmic foci. In some MG132-treated cells, HSP30 staining was substantially depleted in the cytoplasmic regions surrounding these foci. The activation of HSF1 may be involved in MG132-induced hsp gene expression in A6 cells since KNK437 inhibited the accumulation of HSP30 and HSP70. Lastly, MG132 treatment also conferred a state of thermotolerance in A6 cells such that they were able to survive a subsequent thermal challenge. Analysis of this phenomenon is important given the fact that impaired proteasomal activity has been suggested as an explanation for some of the late-onset neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease.
45
陳嘉琪. "The cytotoxic effects of cisplatin, x-ray, and sodium arsenite in non-small cell lung canaer-H1299 cells". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/5ch378.
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碩士國立清華大學
生物科技研究所
92
To determine whether p53 plays a role as a modulator of chemo- and radio- therapeutic agents in NSCLC, the stable transfection of wild-type p53 into H1299 cells were performed. In this study, the role of both wild-type and null p53 in modulating the sensitivity of H1299 cells to three therapeutic agents, cisplatin, X-ray, and sodium arsenite, is examined. The sensitivity to the three agents was tested in the sulforhodamine B (SRB) cell viability assay. The data showed that H1299 cells transfected with wild-type p53 gene had an increase in susceptibility to the three agents (2.3-fold to cisplatin, 1.7-fold to X-ray, and 2.2-fold to sodium arsenite) in comparison with parental or neo-transfected H1299 cells. Furthermore, the apoptotic cell fraction was also determined by dual-parameter flow cytometry after treatment with the three agents. By growing cells in the presence of cisplatin, X-ray, and sodium arsenite, respectively, the apoptotic fractions of H1299-S40 cells increased to 22%, 28%, and 27%, respectively. The expressions of p53, Bak (pro-apoptotic protein) and caspase3 (apoptotic proteolytic enzyme) were examined by Western blot. In p53-transfected H1299-S40 cells p53 proteins were obviously increased after treated individually with the three agents. The results showed similar Bak protein expression was found in both p53-transfected H1299-S40 and null-H1299 cells following cisplatin treatment, but not sodium arsenite treatment or X-ray exposure. In comparison, the active patterns of caspase 3 protein in H1299-S40 cells after above mentioned three agents were dramatically expressed but not in parental H1299 cells. These indicated that the p53 enhanced sensitivities to above three agents in cells through Bak-dependent or Bak-independent (cisplatin) apoptotic pathway. These observations suggest that the increase in chemo- or radio-sensitivity was attributable to wild-type p53 mediation of the process of apoptosis. In the future, the model cell line system could be used in other drugs investigation or p53 molecule related research.
46
CHEN, MEI-FANG y 陳美芳. "Posttreatment of sodium arsenite alters the mutational spectrum induced by ultraviolet light irradiation of Chinese hamster ovary cells". Thesis, 1991. http://ndltd.ncl.edu.tw/handle/38298195218611453868.
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Lee, Shu-Lien y 李叔蓮. "Effects of sodium arsenite on protein carbonylation and nitration in human umbilical vein endothelial cells: two-dimensional electrophoresis analysis". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/75345541471823856169.
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碩士中山醫學大學
營養科學研究所
92
Abstract Recent years, cardiovascular disease was one of the ten most common causes of death in Taiwan. The etiology of cardiovascular disease is contributed to a variety of factors, and the long term exposure of inorganic arsenic is one of them. Although the pathologic mechanism of arsenic on cardiovascular disease is unclear, the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) by arsenic is regarded to be one of the possible candidates. Arsenic caused oxidative stress and nitrative stress caused have been demonstrated to affect cell signaling and cell functions. This study was conducted to examine whether arsenic initiated protein carbonylation and nitration in human umbilical vein endothelial cells (HUVECs). By slot blotting analysis, results show that cellular carbonylated protein level increased 1.6-fold and 1.9-fold in HUVECs treated with 0.5 μM sodium arsenite or 2.0 mM hydrogen peroxide, respectively, as compared with control. In addition, 1.0-10 μM sodium arsenite also increased nitrated protein production as comparated with control. We further identified carbonylated proteins by two-dimensional gel electrophoresis and matrix assist laser desorption ionization time of flight mass spectrometery (MALDI-TOF/MS). As indicated, sodium arsenite seems to preferably modify certain proteins, and the patter of protein carbonylation was different from that of hydrogen peroxide. It suggests that arsenic and hydrogen peroxide may have different pathological effects. Followed by the proteomic analysis, two of arsenic-sensitive proteins were identified to be the α-enolase and actin binding protein-Facin. Due to the role of α-enolase on intracellular glycolysis and Facin on the stability of cytoskeleton, it is compelling to examine whether such an oxidative modification on certain proteins contributes to arsenic toxicity.
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江亭誼. "Tolerance induced by heat or sodium arsenite in trypanosomes isolated from different hosts and electrophoretic analyses of their isozymes". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/40055998242944456844.
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碩士國立中山大學
生物學系
87
Tulahuen (TL) and Corpus Christi (CC) strains of T. cruzi, Trypanosoma conorhini isolated form Triatoma rubrofasciata in Taipei, as well as a chiropteran trypanosome isolated from Kenting were cultivated at 27℃ and used for comparisons of their heat and arsenite tolerance. Their survivals at different temeratures and in different concentrations of sodium arsenite were monitored every 6 hours in the in vitro culture. The bat-trypanosome was identified as a heat-resistant species since it survived at 41℃for at least 24 hours, while CC strain of T. cruzi was considered as an arsenite-resistanst strain since it survived even at a very high concentration. The electrophoretic morbilities of glucose-6-phosphate dehydrogenase (G6PD) and phosphoglucose isomerase (PGI) isozymes of these four isolates of trypanosomes were compared, and an isozyme polymorphism was revealed between different strains of T. cruzi. TL strain of T. cruzi produced more than one isozyme band in both G6PD and PGI. Similar PGI pattern was observed in T. conorhini and the bat-trypanosome. Uniquely, there was not any isozyme bands of G6PD displayed by CC strain of T. cruzi. The correlation between arsenite-resistance and G6PD deficiency required further investigation and G6PD deficiency could be considered as an easier method for the identification of arsenite-resistance in trypanosomes. In cross-treatment studies with T. conorhini by using its survivals as a parameter, it has been found that sodium arsenite induced a transient state of thermotolerance. However, this type of cross-tolerance exhibited by T. conorhini showed only in one direction. Arsenite could induce thermotolerance, but heat could not induce a full protection against this chemical stressor. Results from electrophoretic analyses revealed that the protein of 36 kD decreased in intensity in all three treatments, included heat-induced thermotolerance (H-TT), arsenite-induced arsenite tolerance (A-AT), arsenite-induced thermotolerance (A-TT). However, two proteins corresponding to 72/73 and 90 kD were obviously increased in all three treatments. The band of 54 kD were also inceased in H-TT of T. conorhini, but not in A-AT or A-TT.
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Chang, Kwang-Ning y 張光寧. "4-aminophenylarsine oxide affinity column clarifying 3 proteins of the Chinese hamster ovary cells that modulated by sodium arsenite". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/62268144197720950465.
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碩士國立中央大學
生命科學研究所
87
This thesis was aimed to identify proteins modulated by arsenite in Chinese hamster ovary (CHOA) cells. The toxicity of arsenite has been proposed to resulted from its affinity for thiol groups of proteins. The affinity gel of aminophenylaophenylarsine oxide- Sepharose (PAO-Sepharose), with an arsine oxide moiety, has been employed in purifing proteins with thiol groups. The crude extract from CHOA, SA7 (an arsenic resistant CHOA cells) and SA7N (partila revertant cell from SA7) cells were applied onto the PAO-Sepharose affinity gel, and after extensive washing, the absorbed proteins were eluted with buffers containing 20 mM β- mercaptoethanol (β-ME) or dithiothreitol (DDT). Three proteins over-expressed in either CHOA or SA7 cells were identified by partial amino acid sequence analysis in this study. In the β-ME eluted fraction, two proteins, designed as CHO-M and SA7-M, were predominantly expressed in CHOA and SA7 cells. By amino acid sequence analysis, CHO-M and SA7-M were identified as galectin-1 and glutathione S-transferase π(GSTπ) respectively. In the DTT- eluted fraction, one protein (SA7-D) showed higher expression in SA7 cells. The SA7-D proteins was sequenced and showed homology to thioredoxin peroxidase II. The GSTπ(SA7-M) protein has been shown to facilitate the excretion of arsenite from SA7 cells. The galectin-1 (CHO-M) proteins belong to the galectin family and play important roles in cell proliferation and apotosis, and thioredoxin peroxidase II (SA7-D)is known to have antioxidant activity. However, the association of galectin-1 and thioredoxin peroxidase II with arsenite toxicity has not been well elucidated. Since SA7-M and SA7-D proteins were over-expressed only in SA7 cells (routinely cultured in arsenite-containing medium), but not in CHOA or SA7N cells, and CHO-M was specifically identified in CHOA cells and SA7N, but not in SA7 cells, it seems that these three proteins are be modulated by arsenite treatment to CHOA cells. The role of galectin-I and thioredoxin peroxidase II in arsenic toxicity deserve further study.
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Chang, Ching-Wen y 張競文. "Inhibition of sodium arsenite and hydrogen peroxideinduced apoptosis by phospholipid hydroperoxide glutathione peroxidase (PHGPx) in human epidermoid carcinoma A431 cells". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/84603888795740217448.
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碩士中華醫事學院
生物科技研究所
94
Many of reactive oxygen species that belong to oxygen radicals can lead cells in an oxidative damage. It has been reported that some phenomenons such as aging or tumorigenesis are associated with the damage of oxygen radicals. PHGPx belongs to a kind of antioxidant enzyme in cells that may inhibit the reaction of oxygenation by removing hydroperoxides and decrease the enzyme activity of arachidonate metabolism. Sodium arsenite (NaAsO2), a potent human carcinogen, has not been clearly understood what its carcinogenesis is. It has been suggested that the carcinogenesis of arsenite is associated with oxidative stress. Hydrogen peroxide (H2O2), a potent oxide, can be produced by way of growth factors or respiratory chain of mitochondria in organism. It has been reported the high dose of H2O2 can induce cell apoptosis, oppositely, low dose of H2O2 can inhibit apoptosis. In this study, we focused on whether PHGPx could protect cells from the damage of high dose H2O2 or As3+ in human epidermal carcinoma (A431) cells. First, we established a serial of stable transfectants with differential level of PHGPx expressing. We followed up to observe the appearance of apoptosis with caspase-3 activation or DNA fragmentation under various stimulators. A transfectant with overexpressing tag-PHGPx was more resistant to apoptosis than vector control line under highly concentration of As3+ or H2O2 treatment. In contrast, a transfectant which PHGPx was knockdown by siRNA was more sensitive to apoptosis than vector control line under similar treatment. In addition, we also found that the activation of apoptosis inducing by As3+ was mediated through both caspase-8 (Extrinsic pathway) and caspase-9 (Intrinsic pathway) signaling pathways, but only caspase-8 signal pathway by H2O2. Consequently, we concluded that PHGPx could inhibit the activation not only the extrinsic but also the intrinsic signal pathway in cells, and follow to protect cell from apoptosis under various stimulators.