Submitted by André Chamelete null (andre_ecco@hotmail.com) on 2016-02-12T14:02:00Z No. of bitstreams: 1 Dissertação de Mestrado - FINAL.pdf: 663322 bytes, checksum: 5ca648d67a3a798d08f9c68653ac3ca2 (MD5) / Approved for entry into archive by Sandra Manzano de Almeida (smanzano@marilia.unesp.br) on 2016-02-12T17:20:57Z (GMT) No. of bitstreams: 1 chamelete_a_me_sjrp.pdf: 663322 bytes, checksum: 5ca648d67a3a798d08f9c68653ac3ca2 (MD5) / Made available in DSpace on 2016-02-12T17:20:57Z (GMT). No. of bitstreams: 1 chamelete_a_me_sjrp.pdf: 663322 bytes, checksum: 5ca648d67a3a798d08f9c68653ac3ca2 (MD5) Previous issue date: 2016-01-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O BaP é um contaminante ambiental capaz de causar inflamação e desregulação de vias celulares. Pela ação da CYP1a1 e CYP1b1, é convertido a metabólitos mais reativos. A literatura mostra que o BaP aumenta a expressão de algumas citocinas próinflamatórias, como a IL-1, porém, são bem contraditórios os relatos sobre o efeito do BaP no cFOS, o qual apresenta papel importante na proliferação, na formação de tumores e, possivelmente, na inflamação. O objetivo deste estudo foi de elucidar a participação do receptor purinérgico P2X7 sobre a expressão dos genes IL-1 e cFOS, durante exposição ao BaP. Foi empregado as técnicas de qPCR para quantificação de expressão gênica, e testes de correlação e regressão entre IL-1 e cFOS. A exposição ao BaP induziu a expressão dos dois genes, além das enzimas do seu metabolismo. Quando bloqueado o receptor P2X7, além de uma menor indução das CYPs, os níveis de IL-1 e cFOS caíram abaixo dos níveis controle, sugerindo a participação do P2X7. Os testes de correlação e regressão mostraram uma relação forte direta entre IL-1 e cFOS, reforçando o papel do cFOS na inflamação. / BaP is an environmental contaminant capable to cause inflammation and impair cellular pathways. CYP1a1 and CYP1b1 convert it to more reactive metabolites. Studies show that BaP enhances some proinflammatory citokines expression, like IL-1, yet reports about BaP affecting cFOS, which plays important role in proliferation, tumor formation and inflammation, are controversial. This work aimed to elucidate whether P2X7 purinergic receptor plays a role in IL-1 and cFOS expression during BaP exposure. We applied qPCR techniques to quantify gene expression, correlation and regression assays. Our results showed that BaP raised both IL-1 and cFOS genes expression, besides CYPs ones. Morevoer, when blocking P2X7 receptor, IL-1 and cFOS expression dropped under normal levels, which suggest P2X7 participation, in addition to a smaller enzymes induction. Correlation and regression assays exhibited a strong straight relationship between IL-1 and cFOS expression, reinforcing the role of cFOS in inflammation.

No / Ethylmethanesulphonate (EMS), benzidine (BZD) and benzo[a]pyrene (B[a]P) were assayed for ability to induce mutation at the hprt locus of wild-type L5178Y mouse lymphoma cells. EMS was assayed in the absence of metabolic activation, B[a]P in the presence of metabolic activation (S-9 mix) and BZD both in the absence and presence of S-9. Treatment with EMS minus S-9 and B[a]P plus S-9, especially when the S-9 content of the incubation was 2% (v/v), produced strong dose-related increases in mutant frequency. BZD failed to induce mutation at the hprt locus, either in the absence or presence of S-9.

No description available.

Reconnu par le Centre international de recherche sur le cancer (CIRC) comme cancérigène chez l’être humain, le benzo[a]pyrène (BaP) est un des hydrocarbures aromatiques polycycliques (HAP) les plus étudiés. Souvent rencontrés dans de nombreux milieux de travail, les HAP sont un groupe de polluants omniprésents dans l’environnement, formé par des processus de combustion incomplets. Bien que le BaP présente un risque élevé pour la santé des travailleurs, il n’existe aucun biomarqueur spécifique au composé permettant le suivi et la surveillance d’exposition au BaP dans un lieu de travail. Le 3-hydroxybenzo[a]pyrène (3-OHBaP) est le métabolite du BaP le plus développé comme biomarqueur. Ce métabolite est principalement excrété dans les fèces, ainsi qu’une quantité infime dans l’urine, ce qui le rend difficile à mesurer. De plus, le 3-OHBaP montre une certaine rétention rénale, un facteur qui rend plus compliqué son utilisation en tant que biomarqueur car il oblige de prendre plusieurs critères en compte dans l’analyse de sa cinétique temporelle. Par ailleurs, le 1-hydroxypyrène (1-OHP) est un métabolite urinaire du pyrène souvent utilisé comme biomarqueur d’exposition aux HAP. Neanmoins, il s’agit du métabolite d’un HAP non-cancérigène et par conséquent sa capacité de démontrer le risque de cancer associé à une exposition donnée est faible. Ce mémoire visait à détecter et à évaluer l'exposition au BaP en suivant ses métabolites urinaires: le 4,5-dihydrodiol-benzo[a]pyrène et le 7,8-dihydrodiol-benzo[a]pyrène (le 4,5-diolBaP et le 7,8-diolBaP; les diolBaP). L’évaluation du 4,5-diolBaP et du 7,8-diolBaP s’est déroulée dans deux études: La première étude, surnommée « l’expérience du shampooing », portait sur un volontaire qui s’est exposé aux HAP dans un environnement contrôlé en utilisant un shampooing à base de goudron de houille. Cette étude a été conçue afin d’évaluer l'évolution temporelle du 7,8-diolBaP chez l'homme et de vérifier son potentiel en tant que biomarqueur d'exposition par comparaison avec le 1-OHP dans le même cadre expérimental. Elle a été réalisée avec deux expériences. La première portait sur une seule exposition et la seconde sur une exposition multiple. La deuxième étude, surnommée « l’étude des travailleurs », reposait sur une analyse comparative du 4,5-diolBaP, du 7,8-diolBaP, du 1-OHP et du 3-OHBaP dans un milieu de travail. Cette étude avait pour objectif d’évaluer les compétences des diolBaP dans un contexte réel à côté des biomarqueurs établis d'exposition au BaP et aux HAP. Cinq travailleurs d'une usine de production d'anodes en carbone ont accepté de participer à cette étude. Dans le cadre de ces deux études, les échantillons d'urine étaient analysés par la chromatographie en phase liquide à ultra-haute performance (UHPLC) couplée à la fluorescence. « L’expérience du shampooing » : L’expérience de l’exposition unique et celle de l’exposition multiple ont révélé une élimination de façon mono-exponentielle du 7,8-diolBaP, identique à celle du 1-OHP, avec des concentrations dans le même ordre de grandeur. Nous avons également confirmé un taux d’élimination plus rapide pour le 1-OHP en regardant ses pics. Le 7,8-diolBaP augmente en valeur maximale après chaque exposition, et cette découverte a mis en évidence une accumulation tout au long de la semaine, alors que pour le 1-OHP, le deuxième pic est plus grand, mais le troisième est plus petit, montrant ainsi moins d'accumulation pendant la même période temporelle. « L’étude des travailleurs »: Selon les résultats, la méthode analytique utilisée était incapable de discerner correctement le 4,5-diolBaP des autres contaminants urinaires éluant pendant le même temps de rétention. Le 7,8-diolBaP, quant à lui, élue à des concentrations urinaires d'un ordre de grandeur similaire au 1-OHP tel que vu chez tous les travailleurs évalués. Chez certains travailleurs, la concentration urinaire du 7,8-diolBaP était toujours plus élevée avant le début d'un quart de travail avec l'élimination qui avait lieu pendant le quart de travail pour fournir une valeur de concentration inférieure à la fin du quart de travail. Cependant, la concentration du 1-OHP a eu une hausse immédiate avec l'exposition, culminant à la fin de chaque quart de travail. Pour les autres travailleurs, les concentrations du 7,8-diolBaP et du 1-OHP étaient systématiquement plus élevées à la fin du quart de travail. Il est probable que ces variations indiquent les différentes voies d'exposition. Le présent mémoire a montré le potentiel du 7,8-diolBaP en tant que biomarqueur d'exposition spécifique au BaP et par conséquent, il fournit un point de départ pour explorer la quantification du lien entre l'exposition au BaP et ses effets néfastes sur la santé de l'être humain. L’utilisation de la spectrométrie de masse est nécessaire à confirmer l’identité des diolBaP avant d'aller de l'avant. / Benzo[a]pyrene (BaP) is one of the more commonly studied polycyclic aromatic hydrocarbons (PAHs), a group of omnipresent pollutants in the environment formed through incomplete combustion processes. It is listed as a confirmed carcinogen to human beings by the International Agency for Research on Cancer (IARC) and is highly present in many workplaces. Although presenting a significant health risk to workers, there are currently no convenient compound-specific biomarkers that enable the tracking and monitoring of occupational exposure to BaP. 3-Hydroxybenzo[a]pyrene (3-OHBaP) is the most developed, as a biomarker, amongst the metabolites of BaP. It’s mostly excreted with the faeces, presenting in trace amounts in urine, which makes it difficult to measure; it is also demonstrates renal retention, which adds a layer of complexity in its use as a biomarker because there are many factors to take into consideration when looking at its kinetic time course. 1-Hydroxypyrene (1-OHP), in the other hand, is a urinary metabolite of pyrene that serves as a good representative of PAH presence. It is, however, the metabolite of a non-carcinogenic PAH, and is not fully capable of representing the cancer risk posed in a given scenario. This thesis sought to detect and assess BaP exposure through tracking its urinary metabolites: 4,5-dihydrodiol-benzo[a]pyrene and 7,8-dihydrodiol-benzo[a]pyrene (4,5-diolBaP and 7,8-diolBaP; diolBaPs). 4,5-DiolBaP and 7,8-diolBaP were evaluated through two studies: The first study, the “shampoo experiment”, featured a volunteer who self-exposed to PAHs in a controlled setting by using a coal-tar-based shampoo. The study consisted of two experiments. The first focused on a single exposure and the second on multiple exposures. This study was set to evaluate the time course of 7,8-diolBaP in humans and verifying its potential as a biomarker of exposure through a comparison with 1-OHP in the same experimental framework. The second study consisted of a comparative analysis of 4,5-diolBaP, 7,8-diolBaP, 1-OHP and 3-OHBaP in an occupational setting, evaluating the competency of the diolBaPs in a real-world setting alongside established biomarkers of BaP and PAH exposure. Five workers at a carbon anode production plant volunteered to participate in this study. For both of these studies, the urine samples were analysed by ultra-high-pressure liquid chromatography (UHPLC) coupled with fluorescence. “Shampoo Experiment”: The single and multiple exposures revealed a monoexponential elimination on the part of 7,8-diolBaP, identical to 1-OHP, with similar magnitudes of concentration. 1-OHP was also confirmed to undergo a more rapid elimination from the system, where after each exposure for 7,8-diolBaP, the ensuing peak value is higher. This finding demonstrated evidence of accumulation of 7,8-diolBaP throughout the week, whereas with 1-OHP, the second peak is larger, then the third one is smaller, thus showing less accumulation over the same time frame. “Worker Study”: The results showed that the analytical method used was unable to properly discern 4,5-diolBaP from other urinary contaminants eluting during the same retention time. 7,8-DiolBaP, on the other hand, eluted at urinary concentrations that were a similar order of magnitude to 1-OHP, as can be seen in all of the workers evaluated. For some workers, the urinary concentration of 7,8-diolBaP was consistently at its peak prior to the start of a shift and elimination took place during the shift, to provide a lower concentration value at the end of the shift. With 1-OHP, the rise was immediate with exposure, peaking at the end of every shift. For other workers, both 7,8-diolBaP and 1-OHP are consistently higher at the end of the shift. These variations are likely to indicate different routes of exposure. This thesis showed the potential use of 7,8-diolBaP as a compound-specific biomarker of exposure for BaP and thus provides a starting point in exploring the quantification of BaP exposure and negative health effects in humans. Confirmation of the compound’s identity is needed through the use of mass spectrometry.

Le Benzo(a)pyrène (BaP), appartenant à la famille des hydrocarbures aromatiques polycycliques (HAP) est cancérigène pour l’homme. Nous avons développé une approche protéomique quantitative nanoLC-MS/MS label-free pour identifier des biomarqueurs liés à l’exposition au BaP dans le sécrétome des cellules hépatiques humaines exposées au BaP vs. des cellules non exposées et exposées au Benzo(e)pyrène (BeP). Le BeP, agent non classifié comme cancérigène pour l’homme, est choisi comme contrôle négatif afin de distinguer les protéines spécifiques du BaP de celles des HAP. 847 protéines ont été identifiées et quantifiées, et 55 ont été fortement surexprimées avec un ratio supérieur à 5 : la plupart de ces protéinessurexprimées sont précoces et liées au cancer. Une validation ultérieure de l'expression de ces protéines dans le plasma de la population exposée au BaP aidera dans le développement de biomarqueurs qui permettront d'améliorer la détection précoce, le pronostic et prévention. / Benzo(a)pyrene (BaP) belongs to a class of polycyclic aromatic hydrocarbon and is reported as a potent human carcinogen. We performed a nanoLC-MS/MS-based label-free quantitative proteomics approach to identify potential biomarkers of exposure in the secretome of BaPtreated vs. non-treated and Benzo(e)pyrene (BeP)-treated human hepatoma cell line HepG2.BeP-treated cells were chosen as a negative control to distinguish the BaP-specific from the HAP-specific regulated proteins: BeP is not classifiable as to its carcinogenicity to humans. 847 proteins have been identified and quantified and 55 proteins were seen as being highly upregulated with a fold change of at least 5. Most of these up-regulated proteins were focused incancer-related activities. Further validation of expression of these proteins in the plasma of BaP-exposed population will assist in the development of biomarkers that will greatly improve early detection, prognosis, prediction of treatment response and prevention.

Long interspersed nuclear element-1 (L1) is a genetic element that mobilizes throughout the mammalian genome via retrotransposition and damages host DNA via mutational insertions, chromosomal rearrangements, and reprogramming of gene expression. The cellular mechanisms responsible for aberrant L1 expression during cancer pathogenesis are unclear. Previously, we have shown that L1 reactivation in several human cell lines is dependent upon the activation of aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor member of the PAS superfamily of proteins. We also showed that ectopic expression of L1 reprograms the HepG2 genome leading to epithelial-to-mesenchymal transition (EMT). Here we present evidence that reactivation of L1 and modulation of EMT in HepG2 cells by the AhR ligand benzo(a)pyrene (BaP) is effected through the canonical TGF-β1 signaling pathway. BaP increased TGF-β1 mRNA, SMAD2 phosphorylation and decreased expression of E-Cadherin. The functional relevance of these interactions and the involvement of TGFBR1/ALK5 and SMAD2/3 were confirmed by siRNA interference. Furthermore, expression of L1-encoded ORF1p was positively correlated with the activation of TGF-β1 signaling in human hepatocarcinoma samples at various stages of malignant progression. These results indicate that ligand-mediated AhR activation regulates L1 via canonical TGF-β1 signaling and raise important questions about the molecular etiology of human hepatocarcinomas.

Mice were exposed to diesel exhaust for 9 months prior to evaluation for benzo(a)pyrene disposition. On the last day of exposure the mice were instilled intratracheally with tritiated-benzo(a)pyrene ([3H]BP). The mice were sacrificed at intervals of 2, 24, and 168 hours. Disappearance of radioactivity from lungs and liver was rapid and essentially linear with time. In lungs, liver, and testes; [3H]BP metabolites were found mainly as conjugates, a form readily excretable. Clearance of the hydrocarbon from liver and testes in exposed mice was not markedly different from that in nonexposed mice. However, mice exposed to diesel exhaust had delayed [3H]BP clearance from lungs, possibly due to [3H]BP adsorption to diesel smoke particles.

Ellipticine, an alkaloid isolated from Apocynaceae plants, exhibits significant antitumor and HIV activities. Ellipticine is a pro-drug, whose pharmacological and genotoxic effects depend on activation by cytochromes P450 (CYP) and peroxidases (Px) to a reactive species generating DNA adducts. To elucidate contribution of CYPs (and which of them) and Px to ellipticine activation, we used rat and mouse models, mice with deleted gene of NADPH:CYP reductase in the liver, thus absenting this enzyme in the liver (HRNTM ) and a control mouse line (WT), rats treated with ellipticine, and microsomal systems isolated from the liver of mouse lines and from the liver, kidney and lung of rats. The purified enzymes, CYP1A1 and 3A4, reconstituted with NADPH:CYP reductase were also used. The effect of cytochrome b5, a facultative component of the mixed function monooxygenase system, on ellipticine oxidation by CYP1A1 and 3A4 was also investigated. Carcinogenic benzo(a)pyrene (BaP), known to covalently bind to DNA after its activation with CYPs, was investigated for its potential to generate DNA adducts and to induce CYP and NADPH:CYP reductase enzymes in mouse livers. We investigated an influence of each of components of the mixed function oxidases (MFO) system on metabolism of BaP. CYP1A1 is widely accepted to be the...

Os organismos chamados de algas apresentam uma grande diversidade de espécies e ocupam uma grande variedade de nichos ecológicos. Fundamentais para a manutenção das condições que permitem a vida no planeta, inclusive porque constituem a base de cadeias tróficas de ecossistemas aquáticos, as algas vêm sofrendo com o descarte contínuo de resíduos resultantes das mais variadas atividades humanas. Por outro lado, as algas, ao serem expostas aos poluentes, podem indicar a presença dos mesmos em seus habitats por meio de seus biomarcadores. Neste sentido, este trabalho preocupou-se em caracterizar as bases moleculares da toxicidade do hidrocarboneto policíclico aromático (HPA) benzo(a)pireno (BaP), presente no petróleo cru e derivado da combustão parcial de matéria orgânica, sobre a macroalga vermelha Gracilaria birdiae, uma Rhodophyta marinha nativa. Para avaliar a agressividade do poluente, a alga foi exposta a diferentes concentrações do HPA em água do mar, tanto em situações de exposição aguda (24 e 96h) quanto crônica (7 e 15 dias). Após estes períodos de exposição, alguns biomarcadores bioquímicos e fisiológicos da alga tiveram seus comportamentos analisados. Foram eles: taxas de crescimento (TC); duas defesas antioxidantes: os níveis do tripeptídeo de baixo peso molecular glutationa (GSH) e a atividade da enzima superóxido dismutase (SOD); os níveis do dímero de glutationa GSSG; a fotossíntese da macroalga; e seu aspecto de pigmentação geral. Foi possível observar que BaP é tóxico para a macroalga G. birdiae. Aumentos da concentração do HPA nos meios de cultura das algas provocaram menores TC. A partir destes dados de TC foi possível determinar uma curva de inibição do crescimento da alga e a 7 respectiva IC50 de BaP para um período de exposição de 15 dias, com valor de 69 ng do HPA para cada mL de água do mar. Após diferentes exposições a BaP, incluindo em IC50, algas expostas a BaP apresentaram níveis reduzidos do antioxidante GSH, o mesmo efeito que fora observado para GSSG (com exceção da exposição de 96h). O desempenho fotossintético, a atividade de SOD e a pigmentação de G. birdiae mostraram ser sistemas menos sensíveis à presença de BaP, e foram prejudicados em concentrações mais elevadas do poluente, em torno de 10 a 20 µg/mL. Nestas situações, a despigmentação severa da macroalga foi acompanhada de decaimentos expressivos de alguns parâmetros fotossintéticos (i.e., rETR, RQE, Ik, β) da alga. Numa outra abordagem, alguns experimentos foram feitos com o intuito de descobrir se a alga era capaz de eliminar e biorremediar BaP presente na água do mar. Aparentemente, a alga não apresenta tal capacidade; porém, uma cinética mais detalhada se faz necessária para a confirmação desta observação. Concluindo, os resultados do trabalho corroboram outros dados da literatura a respeito da toxicidade de BaP sobre sistemas vivos. Ainda, apesar de a sensibilidade de G. birdiae a BaP não ter sido alta, foi possível apontar alguns sistemas bioquímicos da alga capazes de desempenhar papel como biomarcadores de exposição ao poluente estudado, o que pode auxiliar na tomada de medidas para o manejo e a conservação de áreas impactadas / Algae show a great biodiversity and occupy many different ecological niches. Besides being essential for the maintenance that allow life on Earth, algae are on the basis of aquatic food chains and they suffer with continuous residue discharge that comes from different human activities. However, once algae are exposed to pollutants, biomarkers can indicate its presence on the environment. The aim of this work was on the characterization of benzo(a)pyrene (BaP; a polycyclic aromatic hydrocarbon (PAH) derived from crude oil and from incomplete combustion of organic matter) toxicity against the red macroalga Gracilaria birdiae, a marine brazillian Rhodophyta. BaP toxicity in marine water was investigated under different exposure concentrations after acute (24 and 96h) and chronic (7 and 15 days) conditions. At the end of the exposures time, some of the algae`s biochemical and physiological biomarkers were analyzed: growth rate (GR); two antioxidant defenses: the low molecular weight peptide glutathione (GSH) and superoxide dismutase (SOD) enzyme activity; glutathione disulfide (GSSG) levels; the macroalga photosynthetic capacity; and the general colour aspect. Increased BaP concentrations led to a decrease of GR values. From GR data it was possible to obtain an inhibition growth curve and the respective BaP IC50 for a 15-day exposure time period with value of 69 ng/mL. After different BaP exposure conditions, including IC50, exposed algae presented decreased GSH levels, the same effects observed for GSSG (except for 96h exposure). The photosynthetic yield, SOD activity and colour aspect of G. birdiae appeared to be more resistant systems against BaP, and were affected only in higher BaP concentrations (10 to 20 µg/mL). In such situations, G. birdiae lost its red colour, which was accompanied by considerable photosynthetic parameters (i.e., rETR, RQE, Ik, β) decay. In a different approach, some experiments were done in order to discover any BaP clean-up and bioremediation played by G. birdiae. Preliminary results suggests that the alga has low remediation efficiency, although more investigations need to be done to confirm this. In summary, the results presented here show similar tendencies with literature data in respect of BaP toxicity against living organisms. Even though G. birdiae presented reasonable resistance to BaP, it was possible to identify some of the alga`s biochemical systems as BaP exposure biomarkers. This situation can be useful for impacted areas assessment and management.

Cells have lesion bypass DNA polymerases (DNAPs), often in the Y-Family, which synthesize passed DNA damage. One class of Y-Family DNAPs includes hDNAP k, EcDNAP IV and SsDbh, which insert accurately opposite N2-dG adducts, including BP-N2-dG formed from benzo[a]pyrene (BP). Another class includes hDNAP h, EcDNAP V and SsDpo4, which insert accurately opposite UV-damage. For correct Watson-Crick pairing between BP-N2-dG and dCTP, the BP moiety must be in the minor groove. On the minor groove side of the active site, k/IV/Dbh-class DNAPs have large openings that accommodate the BP moiety. Primer extension assays with purified proteins show that DNAP IV correctly inserts dCTP opposite BP more than 10-fold faster than it mis-inserts dATP, dGTP, or dTTP. In contrast, h/V/Dpo4-class DNAPs have small active site openings, which cannot accommodate BP and lead to a distorted structure and increased mutagenesis; e.g., Dpo4 has dGTP and dATP insertion rates that are 10-fold greater than those of dCTP. The opening in Dpo4 is plugged and bulky, whereas DNAP IV has a relatively spacious cavity. Consistent with this model, mutants of Dpo4 with a larger opening insert up to 10-fold more accurately opposite BP-N2-dG. Near the active site, Dpo4 has a single non-covalent bridge (NCB) between the little finger domain and the thumb-palm-fingers domain. DNAP IV and Dbh have a second, distal NCB that is 8 angstroms away from the active site towards the 3' end of the template DNA. Dpo4 becomes nearly 5-fold more accurate when mutated to carry a distal NCB, suggesting that NCB's also help control mutagenesis. Lastly, the active site of Dpo4 has a cavity in the major groove side, which may allow base flipping and dGTP insertion opposite -BP, while k/IV/Dbh-type polymerases do not. When this cavity is plugged in Dpo4 by mutagenesis or the introduction of an N-clasp motif, dGTP rates increase by nearly 20-fold. In conclusion, this data suggests that three structural regions contribute to accurate dCTP insertion opposite BP-N2-dG by k/IV/Dbh-class DNAPs: a large opening on the minor groove side near the active site, a cavity on the major groove side, and the number of non-covalent bridges between the little finger domain and the thumb-palm-fingers domain.