Le ciblage de l’activité de l’IFNα est une stratégie développée afin d’augmenter l’index thérapeutique de cette cytokine, dont l’efficacité requiert de fortes doses au site d’action, responsables d’une toxicité systémique. Du fait de l’expression ubiquitaire de son récepteur, le ciblage de l’IFNα par immunocytokine est limité. En se basant sur le concept d'immunocytokine et utilisant un IFNα muté, peu actif, une efficacité de ciblage de 3 log a pu être obtenue, dans le système humain et murin, grâce au rétablissement de l'activité de l'IFNα sur les cellules ciblées. Ces IFNα ciblés sont doués d'une activité biologique, notamment antitumorale, dont la cible cellulaire reste à déterminer. Une stratégie inverse, en cours d'optimisation, permet d'inhiber l’activité des IFN-I spécifiquement sur les cellules ciblées. Cette double stratégie de ciblage de l’activité et de l’inhibition de l’IFN devrait permettre de déterminer les cibles des effets bénéfiques et néfastes des IFN-I, avec des applications thérapeutiques éventuelles. / Targeting IFN activity is a strategy developed to increase the therapeutic index of thiscytokine, whose efficiency requires high doses to site of action, responsible for systemictoxicity. Due to the ubiquitous expression of its receptor, the targeting efficiency of IFNbasedimmunocytokine is limited. Using a mutated IFNα, poorly active, a 3 log targetingefficiency was achieved, in the human and mouse system, by restoring the activity of IFNα ontargeted cells. The biological activity of these targeted IFNα include an antitumoral effect,the cellular target remains to be determined. A reverse strategy being optimized, can inhibitIFN-I activity specifically on targeted cells. This dual targeting strategy of the activity andinhibition of IFN should identify the targets of beneficial and deleterious effects of IFN-I,with possible therapeutic applications.

Metastasis is a major cause of cancer-related deaths and there is a great need for therapies aimed at preventing the spread of cancer, for which lysyl oxidase (LOX), an amino oxidase, plays a crucial role. The general aim of the thesis project was to screen and validate compounds with LOX inhibitory activities. To achieve this goal, we built a pharmacophore model of LOX inhibitors (LOXi) and screened a database of over 4400 compounds with known anti-tumoral activity in cell assays, the Biolab’s database. Top hits from the pharmacophore screening were docked to a LOX crystal structure to assess interactions between predicted inhibitors and the enzyme, and the methodology was implemented using MOE (Molecular Operating Environment) software. The pharmacophore model here developed had 5 features and produced an enrichment factor of 20 in our refinement stage. Biolab’s database screening resulted in the discovery of 344 hits. We docked the top 100 hits against a crystal structure of LOX and the results from the top 10 compounds, ranked by their interaction energy, were further analyzed. Using computer simulation software like MOE, increases the chances of finding a true inhibitor of LOX as compared to random testing of potential inhibitors, thus saving time and resources. / Metastaser är en viktig orsak till cancerrelaterade dödsfall och det finns ett stort behov av behandlingar som syftar till att förhindra spridning av cancer, där lysyloxidas (LOX), ett aminooxidas, spelar en avgörande roll. Det allmänna syftet med avhandlingsprojektet var att screena och validera föreningar med LOX-hämmande aktiviteter genom att konstruera en farmakofilmodell av LOX-hämmare (LOXi) för att screena en databas med föreningar med känd anti-tumoral aktivitet, Biolabs databas. De bästa träffarna från farmakoforscreeningen dockades till en LOX-kristallstruktur för att bedöma interaktioner mellan förutsedda hämmare och enzymet. Metoden implementerades med hjälp av programvaran MOE (Molecular Operating Environment). Den farmakospormodell som utvecklades här hade 5 funktioner och gav en anrikningsfaktor på 20 i vårt förfiningssteg. Biolabs databasscreening resulterade i upptäckten av 344 träffar. Vi dockade de 100 bästa träffarna mot en kristallstruktur av LOX och resultaten från de 10 bästa föreningarna, rangordnade efter deras interaktionsenergi, analyserades ytterligare. Genom att använda datorsimuleringsprogram som MOE ökar chansen att hitta en verklig hämmare av LOX jämfört med slumpmässiga tester av potentiella hämmare, vilket sparar tid och resurser.

Le transfert adoptif de cellules T exprimant un récepteur chimérique reconnaissant un antigène (CAR), est un traitement qui génère des réponses impressionnantes dans les cancers hématologiques mais est beaucoup moins efficace pour le traitement de tumeurs solides. Les tumeurs solides modulent leur microenvironnement induisant des formes multiples d’immunosuppression qui inhibent l’efficacité des fonctions effectrices des cellules T ayant infiltrées la tumeur. Au cours de ma thèse, j’ai évalué le potentiel de deux stratégies pour améliorer les réponses anti-tumorales des cellules T CAR. La première se focalise sur l’étude du rôle potentiel des cellules immunes non T, exprimant un CAR sur la stimulation des fonctions et de la persistance de cellules T CAR+ dans le microenvironnement tumoral. Afin d’étudier la fonction des cellules CAR non T, nous avons généré un modèle de souris transgénique (vav-CAR) dans lequel les cellules immunes expriment un CAR reconnaissant l’antigène tumoral Her2 (ErbB2). Comme attendu, les cellules T CAR+ possèdent des fonctions anti-tumorales, mais nous avons aussi mis en évidence que les macrophages et les cellules NK exprimant le CAR montraient une réponse cytokinique, cytotoxique et phagocytiques spécifiques de l’antigène. De plus, en utilisant le modèle vav-CAR, nous avons démontré le potentiel des cellules immunes CAR+ dans le rejet des tumeurs et cela indépendamment des cellules T CD8+. Les cellules T CD4+ sont essentielles puisque leur élimination réduit considérablement les réponses anti-tumorales dans notre modèle vav-CAR. Il a été démontré que certaines sous-populations de cellules T auxiliaires participent aux réponses anti-tumorales avec les cellules Th1 et Th17 démontrant une efficacité plus robuste que les autres sous-populations. Notre deuxième stratégie s’est focalisée sur l’étude de l’impact du métabolisme au cours de la polarisation des cellules T CD4+ et plus particulièrement lors de la différenciation des cellules T CAR+ en cellules Th1. En effet, l’activation et différenciation des cellules T sont fortement associées à une augmentation des besoins métaboliques. Dans le microenvironnement tumoral, en raison de la forte demande en ressources de la tumeur, la déprivation en nutriments ainsi générée peut limiter l’accès aux nutriments d’autres types cellulaires et ainsi altérer le devenir et les fonctions des cellules immunes greffés infiltrant la tumeur. En conséquence, modifier les cellules immunes CAR+ afin qu’elles puissent résister à la compétition métabolique du microenvironnement tumoral pourrait leur permettre de conserver leurs fonctions effectrices. En étudiant l’impact de la déprivation en nutriments sur la différenciation des cellules T, nous avons trouvé que des concentrations limitantes en glutamine, l’acide aminé le plus abondant du plasma, inhibaient le potentiel des cellules T à se différencier vers la voie Th1 associée à la production d’IFNγ. Au contraire, cette condition favorisait la conversion de cellules T CD4 naïves en cellules régulatrices Foxp3+ ayant des fonctions suppressives (Tregs). De plus, nous avons montré que la présence d’un seul métabolite dérivé de la glutamine, l’α-ketoglutarate (αKG), suffisait à augmenter les fonctions effectrices anti-tumorales de plusieurs sous-types de cellules T auxiliaires CAR+, augmentant la production d’IFNγ et diminuant l’expression de FOXP3. Ainsi, durant ma thèse, j’ai développé un modèle murin vav-CAR, générant un outil permettant d’étudier et manipuler les fonctions de multiples populations de cellules immunitaires exprimant un CAR. Ce modèle permettra de promouvoir l’utilisation de cellules immunes optimisées exprimant un CAR dans le cadre d’immunothérapies dirigées contre des tumeurs solides. De plus, en utilisant ce modèle, nous avons identifié un métabolite de la glutamine, qui orchestre les réponses immunitaires au moyen d’une reprogrammation métabolique des cellules T CD4. / The adoptive transfer of T cells expressing a chimeric antigen receptor (CAR) as a treatment for cancer has achieved impressive responses in haematological malignancies, but has been less successful in the treatment of solid tumors. The tumor microenvironment of solid tumors presents multiple forms of immunosuppression, inhibiting the efficient effector function of infiltrating anti-tumor T cells. During my PhD, we assessed the potential of two strategies to enhance the anti-tumor function of CAR T cells. The first focuses on the potential of other CAR-expressing immune subsets to stimulate CAR T cell function and persistence in the tumor microenvironment. To elucidate the function of CAR-expressing non-T lymphocytes, we generated a transgenic mouse model (vav-CAR) in which immune cells express a CAR against the Her2 (ErbB2) tumor antigen. As expected, CAR T cells harboured anti-tumor function but we also found that CAR-modified macrophages and natural killer cells (NKs) exhibited significant antigen specific cytokine secretion, cytotoxicity and phagocytosis. Moreover, using the vav-CAR model, we demonstrated the potential of CAR immune cells to mediate tumor rejection independently of CD8+ T cells. CD4+ T cells were critical for this response as their deletion severely abrogated the anti-tumor responses in our vav-CAR model. Distinct T helper subsets have been shown to participate to anti-tumor responses, with Th1 and Th17 cells demonstrating a more robust efficacy as compared to other T helper subsets. Our second strategy was focused on the impact of metabolism in the polarisation of CD4+ T cells, in particular the differentiation of CAR T cells to Th1 lineage. T cell activation and polarisation is highly associated with increased metabolic needs. Given that nutrient deprivation in the tumor microenvironment, due to a high demand of the tumor for resources, can limit the nutrients available for other cell types, the fate and function of adoptively transferred immune cells may be altered upon entering the tumor. Therefore, modifying CAR immune cells to resist metabolic suppression in the tumor microenvironment may help retain their effector functions. Upon assessing the effects of nutrient deprivation on T cell differentiation, we found that limiting concentrations of glutamine, the most abundant amino acid in the plasma, inhibited the potential of T cells to undergo Th1 differentiation with associated IFNγ secretion. Rather, this condition resulted in the conversion of naïve CD4+ T cells into suppressive Foxp3+ regulatory T cells (Tregs). Furthermore, we determined that a single glutamine-derived metabolite, α-ketoglutarate (αKG), enhanced the anti-tumor effector functions of multiple CAR T helper subsets, increasing the production of IFNγ and reducing FOXP3 expression.Thus, during my PhD, I generated a vav-CAR model, providing a platform in which the function of multiple CAR-bearing immune subsets can be studied and manipulated. This model will promote the utilisation of optimized CAR-bearing immune cells in adoptive immunotherapy for solid tumors. Furthermore, using the CAR model, we have identified a glutamine metabolite that orchestrates immune responses through the metabolic reprogramming of CD4 T cells.

As fosfolipases A2 (PLA2s, E.C. 3.1.1.4) pertencem a uma superfamília de enzimas que realizam a clivagem de fosfolipídios da membrana celular em ácidos graxos e lisofosfolipídios, numa reação dependente de cálcio. As PLA2s apresentam um importante papel em várias funções celulares, incluindo manutenção dos fosfolipídios celulares, geração de prostaglandinas e leucotrienos, tradução de sinais, proliferação celular e contração muscular. O presente trabalho teve como objetivo a caracterização estrutural e funcional de uma fosfolipase A2 ácida tóxica(BmooTX-I) isolada da peçonha da serpente Bothrops moojeni. A BmooTX-I foi purificada por uma combinação de cromatografias em resinas de troca iônica (DEAE-Sephacel), exclusão molecular (Sephadex G-75) e interação hidrofóbica (Phenyl-Sepharose CL-4B). A confirmação do grau de pureza foi realizada através de análise por espectrometria de massa MALDI TOF da BmooTX-I reduzida (monômero, 13.802,66 Da) e não reduzida (dímero, 27.506,38 Da), da focalização isoelétrica (pI 4,2) e de SDS-PAGE. A região N-terminal da enzima apresentou alta homologia com outras PLA2s Asp49 de peçonhas de serpentes. A BmooTX-I apresentou também elevada atividade fosfolipásica e induziu edema moderado in vivo. Além disso, foi capaz de inibir a agregação plaquetária e a coagulação do plasma, induzir a liberação de PGI2 por HUVECs e apresentar efeito citotóxico sobre células tumorais, bactérias e fungos. O tratamento da enzima com o reagente brometo de p-bromofenacila (BPB) neutralizou a atividade enzimática e de inibição da agregação plaquetária. A determinação da miotoxicidade foi realizada através da dosagem dos níveis de CK no plasma de camundongos previamente injetados com a toxina. A análise histopatológica das fibras musculares demonstrou a presença de infiltrado inflamatório e líquido intercelular, ambos confirmados pela análise ultra-estrutural. O presente trabalho deverá contribuir para a elucidação e determinação da composição bioquímica dos venenos animais, já que as fosfolipases A2 ácidas tóxicas possuem mecanismos de ação ainda não totalmente esclarecidos. / Phospholipases A2 (PLA2s, EC 3.1.1.4) belong to a superfamily of enzymes that perform the cleavage of phospholipids of cell membranes in fatty acids and lysophospholipids in a calcium dependent reaction. PLA2s have an important role in several cellular functions, including maintenance of cellular phospholipids, the generation of prostaglandins and leukotrienes, translation signals, cell proliferation and muscle contraction. This study aimed at the structural and functional characterization of an acidic and toxic phospholipase A¬2 (BmooTX-I) isolated from Bothrops moojeni snake venom. BmooTX-I was purified by a combination of chromatographic steps on resins of ion exchange (DEAE Sephacel), molecular exclusion (Sephadex G-75) and hydrophobic interaction (Phenyl Sepharose CL-4B). The confirmation of the purity degree was analyzed by MALDI TOF mass spectrometry of reduced BmooTX-I (monomer, 13,802.66 Da) and not reduced (dimer, 27,506.38 Da), by isoelectric focusing (pI 4.2) and by SDS-PAGE. The N-terminal region of the enzyme showed high homology with other Asp49 PLA2s of snake venoms. BmooTX-I also presented high phospholipase activity and induced moderate edema in vivo. Furthermore, this enzyme was capable of inhibiting platelet aggregation and plasma coagulation, inducing the release of PGI2 by HUVECs, also showing cytotoxic effects on tumor cells, bacteria and fungi. Treatment of the enzyme with the p-bromophenacyl bromide (BPB) neutralized the enzymatic activity and the inhibition of platelet aggregation. The determination of myotoxicity was accomplished through the determination of the CK levels in plasma of mice previously injected with the toxin. The histopathological analysis of muscle fibers showed the presence of inflammatory infiltration and intercellular fluid, both confirmed by ultrastructural analysis. This work contributes to the elucidation and determination of the biochemical composition of animal venoms, since the mechanisms of action of toxic acidic phospholipases A2 are not yet fully understood.

A planta Casearia sylvestris é catalogada como planta medicinal de interesse ao SUS, indicada para o tratamento de gastrite e como cicatrizante, para ser utilizada na forma de infusão ou compressas. Assim, foi objetivo deste estudo avaliar o potencial terapêutico antiulcerogênico do extrato fluido (EF), extrato metanólico (EM) e fração diclorometano (FDM), pelo modelo de indução de úlcera por etanol-acidificado. Realizou-se também a análise fitoquímica objetivando identificar os compostos ativos presentes nos extratos, através de técnicas de cromatografia, espectrometria de massas e ressonância magnética nuclear. Os resultados obtidos mostraram que tanto o EF, quanto o EM e FDM foram eficazes na prevenção de úlceras gástricas. Além disso, foram avaliados os possíveis efeitos do EF no estresse oxidativo hepático e na indução ou inibição do complexo enzimático citocromo P450. Os resultados obtidos mostraram alteração apenas do ciclo-redox da glutationa com a razão GHS/GSSG diminuída nos animais tratados, sugerindo que deve ser ter cautela ao utilizá-lo concomitantemente a medicamentos pelo risco de interações medicamentosas. Adicionalmente, foi realizado um estudo preliminar do potencial antitumoral do EM e frações através de ensaio bioguiado de citoxicidade (ensaio sulforrodamina B), no qual foi observado pronunciada atividade citotóxica (IC50 ≤ 5µ/ml) em diferentes linhagens tumorais. A análise fitoquímica identificou flavonóides (quercetina, rutina, kaempferol) e terpenos (espatulenol, diterpeno clerodânico). Portanto, pode-se sugerir que os efeitos terapêuticos ocorrem da sinergia destes princípios ativos / The Casearia sylvestris plant is cataloged as a medicinal plant of interest to the Unified Health System in Brazil indicated for the treatment of gastritis and healing, to be used in the form of infusion or compresses. Thus, the aim of this study was to evaluate the antiulcerogenic therapeutic potential of fluid extract (EF), methanol extract (EM) and dichloromethane fraction (FDM) on ethanol/HCl induced gastric model ulcer. The results obtained showed that EF, as EM and FDM, have been effective in preventing gastric ulcers. Also, a phytochemical analysis by chromatographic techniques, mass spectrometry and nuclear magnetic resonance was carried out to identify the active constituents present in the extracts. Moreover the possible effects of EF on hepatic oxidative stress and on induction or inhibition of cytochrome P450 enzime complex were evaluated. The results obtained showed only an alteration on the redox-cycle of glutathione with the GHS/GSSG ratio decreased in treated animals, suggesting caution in the use of EF concomitantly with other drugs as there might be a risk of drug interactions. In addition, a preliminary study was carried out to evaluate through bio-guided citotocixity assay (sulforhodamine B) the antitumor potential of the EM and fractions, in which pronounced cytotoxic activity was observed (IC50 ≤ 5µg/ml) in different tumor cell lines. Therefore, it can be suggested that the therapeutic effects occur in consequence of the synergy of these active ingredients

A planta Casearia sylvestris é catalogada como planta medicinal de interesse ao SUS, indicada para o tratamento de gastrite e como cicatrizante, para ser utilizada na forma de infusão ou compressas. Assim, foi objetivo deste estudo avaliar o potencial terapêutico antiulcerogênico do extrato fluido (EF), extrato metanólico (EM) e fração diclorometano (FDM), pelo modelo de indução de úlcera por etanol-acidificado. Realizou-se também a análise fitoquímica objetivando identificar os compostos ativos presentes nos extratos, através de técnicas de cromatografia, espectrometria de massas e ressonância magnética nuclear. Os resultados obtidos mostraram que tanto o EF, quanto o EM e FDM foram eficazes na prevenção de úlceras gástricas. Além disso, foram avaliados os possíveis efeitos do EF no estresse oxidativo hepático e na indução ou inibição do complexo enzimático citocromo P450. Os resultados obtidos mostraram alteração apenas do ciclo-redox da glutationa com a razão GHS/GSSG diminuída nos animais tratados, sugerindo que deve ser ter cautela ao utilizá-lo concomitantemente a medicamentos pelo risco de interações medicamentosas. Adicionalmente, foi realizado um estudo preliminar do potencial antitumoral do EM e frações através de ensaio bioguiado de citoxicidade (ensaio sulforrodamina B), no qual foi observado pronunciada atividade citotóxica (IC50 ≤ 5µ/ml) em diferentes linhagens tumorais. A análise fitoquímica identificou flavonóides (quercetina, rutina, kaempferol) e terpenos (espatulenol, diterpeno clerodânico). Portanto, pode-se sugerir que os efeitos terapêuticos ocorrem da sinergia destes princípios ativos / The Casearia sylvestris plant is cataloged as a medicinal plant of interest to the Unified Health System in Brazil indicated for the treatment of gastritis and healing, to be used in the form of infusion or compresses. Thus, the aim of this study was to evaluate the antiulcerogenic therapeutic potential of fluid extract (EF), methanol extract (EM) and dichloromethane fraction (FDM) on ethanol/HCl induced gastric model ulcer. The results obtained showed that EF, as EM and FDM, have been effective in preventing gastric ulcers. Also, a phytochemical analysis by chromatographic techniques, mass spectrometry and nuclear magnetic resonance was carried out to identify the active constituents present in the extracts. Moreover the possible effects of EF on hepatic oxidative stress and on induction or inhibition of cytochrome P450 enzime complex were evaluated. The results obtained showed only an alteration on the redox-cycle of glutathione with the GHS/GSSG ratio decreased in treated animals, suggesting caution in the use of EF concomitantly with other drugs as there might be a risk of drug interactions. In addition, a preliminary study was carried out to evaluate through bio-guided citotocixity assay (sulforhodamine B) the antitumor potential of the EM and fractions, in which pronounced cytotoxic activity was observed (IC50 ≤ 5µg/ml) in different tumor cell lines. Therefore, it can be suggested that the therapeutic effects occur in consequence of the synergy of these active ingredients

Le TGFE (Transforming Growth Factor-E) est une cytokine ayant de nombreusesfonctions au cours de la vie embryonnaire et de la vie adulte. Au cours de la cancérogenèse,le TGFE a un effet anti-tumoral sur les épithelia sains ou immortalisés, et acquière despropriétés facilitant la progression tumorale des épithélia transformés. Afin d'étudier cettedualité fonctionnelle du TGFE, nous avons choisi comme modèle d'étude l'adénocarcinomedu pancréas, une tumeur de très mauvais pronostic, qui représente la cinquième cause demortalité par cancer dans les pays développés. Les cancers du pancréas, dans leur grandemajorité, présentent des mutations activatrices de l'oncogène Kras, sécrètent de grandequantités de TGFβ et présentent des mutations inactivatrices au niveau de gènes régulateursde la voie du TGFβ. L'objectif général de mes travaux de thèse était de comprendre le rôle duTGFβ au cours des différentes phases de la cancérogenèse pancréatique grâce à l'utilisationde souris génétiquement modifiées. Tout d'abord, nous avons montré que l'activation cibléede la voie du TGFβ dans le pancréas coopérait avec l'oncogène Kras afin d'induire unepancréatite, une inflammation du pancréas favorisant le développement tumoral. Nous avonségalement démontré le rôle suppresseur de tumeur de TIF1γ, une protéine dont la fonction estméconnue mais qui a été proposée pour réguler la voie du TGFβ. En conclusion, mes travauxont tout d'abord contribué à une meilleure compréhension des mécanismes à l'origine del'inflammation du pancréas. Ceci ouvre de nouvelles perspectives de traitement visant àinactiver le programme pro-inflammatoire du TGFβ et ainsi d'inhiber l'effet pro-tumoral dela pancréatite. D'autre part, mes travaux ont permis de mettre en évidence une nouvelle voiesuppresseur de tumeur dans le pancréas. La caractérisation des programmes anti-tumorauxmis en jeu par TIF1γ devrait permettre de définir de nouvelles stratégies thérapeutiques.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-04-04T13:49:10Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Maria Ester Barros_CD_4.pdf: 6351675 bytes, checksum: 1634d753cabb911bd4c0cf8e58182237 (MD5) / Made available in DSpace on 2017-04-04T13:49:10Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Maria Ester Barros_CD_4.pdf: 6351675 bytes, checksum: 1634d753cabb911bd4c0cf8e58182237 (MD5) Previous issue date: 2015-05-01 / CNPQ / A primeira parte deste trabalho envolveu o estudo de docking molecular, a síntese, e a avaliação das atividades antitumorais e anti-inflamatórias de lactonas -insaturadas, análogos estruturais da (-)-Massoialactona, produto natural com conhecida atividade farmacológica. O alvo biológico selecionado para o estudo de docking foi a CRM-1, e tal estudo revelou o potencial biológico dos análogos propostos. Estes análogos foram sintetizados em rendimentos que variaram entre 65-75%, e as suas atividades antitumoral e anti-inflamatória foram avaliadas, sendo que um deles mostrou-se bastante promissor. Estudos posteriores de docking molecular da lactona mais promissora revelou que, apesar dos isômeros R e S assumirem diferentes encaixes no sítio ativo da CRM-1, não há diferença significativa na energia de ligação entre esses isômeros e o alvo molecular estudado. A segunda etapa deste trabalho envolveu o estudo de docking molecular, a síntese, e a avaliação da atividade antitumoral de Z-estilbenos, análogos da Combretastatina A-4 (CA-4). O alvo biológico selecionado para o estudo de docking molecular foi o domínio da colchicina na tubulina. Os cálculos teóricos dos análogos estruturais propostos revelaram que seis desses compostos apresentam diferenças significativas nos valores de energia de ligação quando comparados com o valor teórico calculado para a CA-4, ou seja, teoricamente seriam mais ativos que o produto natural. Dos análogos selecionados a partir do docking molecular, dois foram sintetizados em bons rendimentos empregando-se como precursores teluretos vinílicos e organotrifluoroboratos de potássio. A posterior avaliação da atividade antitumoral dos compostos sintetizados revelou que os resultados obtidos estavam em concordância com o previsto no estudo teórico. / The first part of this work involved the study of molecular docking, synthesis, and the evaluation of anti-tumor and anti-inflammatory activities of unsaturated-lactones, structural analogues of (-)-Massoialactone, a natural product with known pharmacological activity. The biological target selected for the docking study was the CRM-1 and this study revealed the biological potential of the proposed analogues. These analogues were synthesized in yields ranging from 65-75%, and its anti-tumor and anti-inflammatory activities were evaluated, being one of them very promising. Further studies of molecular docking using the most promising lactone revealed that despite the R and S isomers take different fittings in the active site of CRM-1, there is no significant difference in binding energy between these isomers and the molecular target studied. The second step of this work involved the study of molecular docking, synthesis, and evaluation of antitumor activity of Z-stilbenes, analogues of combretastatin A-4. The biological target selected for the study of molecular docking was the domain of colchicine in tubulin. Theoretical calculations of the proposed structural analogues revealed that six of these compounds shown significant differences in binding energy values compared to the theoretical values calculated for the CA-4, ie, theoretically, the proposed compounds would be more active than the natural product. From the selected analogs proposed by molecular docking, two were synthesized in good yields employing vinyl tellurides and potassium organotrifluoroborates as precursors. Further evaluation of the antitumor activity of the synthesized compounds showed that the results were in agreement with the theoretical study.

As fosfolipases A2 (PLA2s, E.C. 3.1.1.4) pertencem a uma superfamília de enzimas que realizam a clivagem de fosfolipídios da membrana celular em ácidos graxos e lisofosfolipídios, numa reação dependente de cálcio. As PLA2s apresentam um importante papel em várias funções celulares, incluindo manutenção dos fosfolipídios celulares, geração de prostaglandinas e leucotrienos, tradução de sinais, proliferação celular e contração muscular. O presente trabalho teve como objetivo a caracterização estrutural e funcional de uma fosfolipase A2 ácida tóxica(BmooTX-I) isolada da peçonha da serpente Bothrops moojeni. A BmooTX-I foi purificada por uma combinação de cromatografias em resinas de troca iônica (DEAE-Sephacel), exclusão molecular (Sephadex G-75) e interação hidrofóbica (Phenyl-Sepharose CL-4B). A confirmação do grau de pureza foi realizada através de análise por espectrometria de massa MALDI TOF da BmooTX-I reduzida (monômero, 13.802,66 Da) e não reduzida (dímero, 27.506,38 Da), da focalização isoelétrica (pI 4,2) e de SDS-PAGE. A região N-terminal da enzima apresentou alta homologia com outras PLA2s Asp49 de peçonhas de serpentes. A BmooTX-I apresentou também elevada atividade fosfolipásica e induziu edema moderado in vivo. Além disso, foi capaz de inibir a agregação plaquetária e a coagulação do plasma, induzir a liberação de PGI2 por HUVECs e apresentar efeito citotóxico sobre células tumorais, bactérias e fungos. O tratamento da enzima com o reagente brometo de p-bromofenacila (BPB) neutralizou a atividade enzimática e de inibição da agregação plaquetária. A determinação da miotoxicidade foi realizada através da dosagem dos níveis de CK no plasma de camundongos previamente injetados com a toxina. A análise histopatológica das fibras musculares demonstrou a presença de infiltrado inflamatório e líquido intercelular, ambos confirmados pela análise ultra-estrutural. O presente trabalho deverá contribuir para a elucidação e determinação da composição bioquímica dos venenos animais, já que as fosfolipases A2 ácidas tóxicas possuem mecanismos de ação ainda não totalmente esclarecidos. / Phospholipases A2 (PLA2s, EC 3.1.1.4) belong to a superfamily of enzymes that perform the cleavage of phospholipids of cell membranes in fatty acids and lysophospholipids in a calcium dependent reaction. PLA2s have an important role in several cellular functions, including maintenance of cellular phospholipids, the generation of prostaglandins and leukotrienes, translation signals, cell proliferation and muscle contraction. This study aimed at the structural and functional characterization of an acidic and toxic phospholipase A¬2 (BmooTX-I) isolated from Bothrops moojeni snake venom. BmooTX-I was purified by a combination of chromatographic steps on resins of ion exchange (DEAE Sephacel), molecular exclusion (Sephadex G-75) and hydrophobic interaction (Phenyl Sepharose CL-4B). The confirmation of the purity degree was analyzed by MALDI TOF mass spectrometry of reduced BmooTX-I (monomer, 13,802.66 Da) and not reduced (dimer, 27,506.38 Da), by isoelectric focusing (pI 4.2) and by SDS-PAGE. The N-terminal region of the enzyme showed high homology with other Asp49 PLA2s of snake venoms. BmooTX-I also presented high phospholipase activity and induced moderate edema in vivo. Furthermore, this enzyme was capable of inhibiting platelet aggregation and plasma coagulation, inducing the release of PGI2 by HUVECs, also showing cytotoxic effects on tumor cells, bacteria and fungi. Treatment of the enzyme with the p-bromophenacyl bromide (BPB) neutralized the enzymatic activity and the inhibition of platelet aggregation. The determination of myotoxicity was accomplished through the determination of the CK levels in plasma of mice previously injected with the toxin. The histopathological analysis of muscle fibers showed the presence of inflammatory infiltration and intercellular fluid, both confirmed by ultrastructural analysis. This work contributes to the elucidation and determination of the biochemical composition of animal venoms, since the mechanisms of action of toxic acidic phospholipases A2 are not yet fully understood.

Deux approches potentiellement anti-tumorales, employant des nanoparticules magnétiques (NPMs) et des champs magnétiques oscillants, furent étudiées. La première, l’hyperthermie magnétique, utilise l’échauffement de NPMs au contact des cellules tumorales provoqué par un champ magnétique alternatif haute-fréquence. Durant cette thèse, il fut démontré que les forces magnéto-mécaniques induites par les inhomogénéités de champ magnétique pendant un essai d’hyperthermie magnétique n’avaient aucune influence sur la viabilité cellulaire. Egalement, des mesures magnétiques, d’XPS, et de puissance de chauffe de NPMs de fer enrobées d’une coquille de silice amorphe furent effectuées et analysées. Il fut observé que cette coquille permettait de préserver les propriétés magnétiques des NPMs suite à l’exposition à un environnement aqueux. La deuxième approche anti-tumorale utilise des NPMs soumises à un champ magnétique basse-fréquence, induisant une stimulation mécanique des cellules tumorales. Une étude théorique complète de l’influence du champ magnétique, de l’agitation thermique et des interactions magnétiques sur la force magnéto-mécanique exercée par des NPMs, fut effectuée. Elle démontra notamment que cette force augmente de manière drastique pour une assemblée de NPMs lorsque la rotation du champ magnétique induit une rupture de symétrie dans l’évolution temporelle du couple magnéto-mécanique. Expérimentalement, il fut développé différents prototypes de génération de champ magnétique tournant à basse fréquence. Des tests in vitro furent réalisés en utilisant des NPMs enrobées par une matrice de phosphatidylcholine, leur permettant d’être solidaires des membranes cellulaires. Suite à la rotation d’un champ magnétique de 40 ou 380 mT, à 10 Hz, il fut observé une réduction de la survie cellulaire. / Two anti-tumor treatments based on magnetic nanoparticles (MNPs) and oscillating magnetic field were studied. The first one, magnetic hyperthermia, uses the heat released by MNPs in contact with tumor cells under a high frequency alternating magnetic field. We have shown that the forces induced by magnetic field inhomogeneity during magnetic hyperthermia essay no influence on cellular viability. Moreover, magnetic measurements, XPS characterization and heating power evaluation of iron MNPs coated by amorphous silica shell were carried out. It was observed that this shell is able to preserve the MNP magnetic properties submitted to an aqueous environment. The second anti-tumor treatment combines MNPs and low-frequency magnetic field, inducing mechanical stress to tumor cells. A complete theoretical study on the influence of magnetic field, thermal agitation and magnetic interaction on the magneto-mechanical forces generated by the MNPs was carried out. It was demonstrated that for a MNP assembly this force increases dramatically when the rotation of the magnetic field induces a break of time reversal symmetry on the magneto-mechanical torque. Experimentally, several devices generating low frequency rotating magnetic fields were developed. Using these devices, in-vitro essays were also achieved using phosphatidylcholine coated MNPs, which bind to cellular membranes. An application of a 40 or 380 mT magnetic field rotating at 10 Hz reduced cell survival rate.