Made available in DSpace on 2016-04-26T14:53:11Z (GMT). No. of bitstreams: 1 Gustavo Ferreira Simoes.pdf: 26632165 bytes, checksum: ab38215424bd678db9b9d98e6ea5409e (MD5) Previous issue date: 2011-06-08 / Fundação de Amparo a Pesquisa do Estado de São Paulo / The emergence of the author function in the 19th century, as pointed out by Michel Foucault, was characterized by the investment in organizing, affiliating and homogenizing the diffusion of discourses from previous centuries. The author signature has risen as an existence entitled with a different status from those that used the word ordinarily at the same time that it was identified as the possible danger to be fought. Considering Foucault s suggestions, I have followed Roberto Freire s writings, with no intent of explaining it, while articulating it with his life experiences since the liberation of DOPS s dungeons, in 1965, a year after the military coup of 1964, until the publication of his last writings in the end of the 20th century. Freire s writings update the exercise of social literature undertaken by some libertarians in the beginning of the 20th century in Brazil. However, his books are not inspired by the thought of the socalled classical anarchists, but by the practices that have emerged with the protests, particularly those connected to customs, triggered by the events of 1968. Freire, dissociating himself from the projects of revolution, began to value, in the 1970s, through his books and life, certain experiences with the body, in the present, associating it to an anarchist sensualization of the existence. The analysis of his journey since 1960 when he was an activist in Ação Popular and through his experiences with The Living Theater, Wilhem Reich and the anarchism in the 1980 and 1990 was possible given the distance he kept from the notion of author. Freire s writings have been developed in movement. Therefore, one cannot impose on it a unity or explanatory restrain. Freire has dangerously sailed with his literature in the late 20th century. The navigation, according to Michel Foucault, was a privileged metaphor to those immersed in an ethical and aesthetical life in the Hellenistic and Roman antiquity. By affirming this navigation, this existence, he moved like a libertarian pilot, like an anarchist pirate / A emergência da função autor , no século XIX, como salientou Michel Foucault, caracterizava-se pelo investimento em organizar, filiar e homogeinizar a dispersão dos discursos oriunda dos séculos anteriores. A assinatura do autor irrompia como existência que possuía um status distinto daqueles que utilizavam a palavra ordinariamente, ao mesmo tempo, em que era identificada como um possível perigo a ser combatido. Seguindo as sugestões de Foucault, observei a escrita de Roberto Freire visando não explicar mas acompanhá-la em seu movimento, articulando-a às experiências da vida de Freire, desde a liberação no porão do DOPS, em 1965, um ano após o golpe militar de 1964, até a publicação de seus últimos escritos no final do século XX. A escritura de Freire atualiza o exercício da literatura social empreendida por certos libertários do início do século XX, no Brasil. Entretanto, seus livros não são animados pela reflexão dos anarquistas considerados clássicos, mas pelas práticas que irromperam com as contestações, sobretudo as ligadas aos costumes, detonadas pelos acontecimentos de 1968. Afastando-se ao longo da vida dos projetos de revolução, Freire passou a valorizar a partir da década de 1970, em seus livros e na vida, certas experiências com o corpo, no presente, associando-as a uma sensualização anarquista da existência. A análise do percurso traçado por ele desde a década de 1960, quando ainda militava na Ação Popular, passando pela descoberta do Living Theater, Wilhem Reich e afirmação do anarquismo nas décadas de 1980 e 1990, foram possíveis precisamente por um afastamento da noção de autor. A escrita de Freire se desenhou em movimento. Portanto, não há como lhe impor uma unidade, um travão explicativo. Freire navegou, junto com sua literatura, durante a segunda metade do século XX, perigosamente. A navegação, segundo Michel Foucault, era metáfora privilegiada para aqueles que se ocupavam com a vida ética e esteticamente na antiguidade helenística e romana. Afirmando essa navegação, a existência, ele deslizou como um piloto libertário, um pirata anarquista

Water resources are increasingly precious, so wastewater reclaiming has become an important source of water nowadays. There are many types of industry including conventional and hi-tech ones in the selected industrial processing zone, where different process wastewaters are treated by a centralized wastewater treatment plant. The effluent is then discharged into the ocean (EDO). On the other hand, among several other industries backside grinding (BG) wastewater generated by the IC (integrated-circuit) packaging and testing industry is treated by their owned wastewater treatment plants and then discharged onto land (EDL). Normally, BG wastewater is huge in quantity and it contains microscale and nanoscale particles. The objectives of this research were two-fold: (1) to evaluate the feasibility of using two tubular ceramic membranes (microfiltration and ultrafiltration) coupled with the electrocoagulation/electrofiltration (EC/EF) process to effectively treat the effluent discharged into the ocean, effluent discharged onto land, and BG wastewater for the purpose of reclamation; and (2) to investigate the best time for backwashing of membranes through the analysis of components of membrane fouling using resistances in series model. The experimental results showed that the ultrafiltration (UF) membrane (i.e., tubular TiO2/Al2O3 composite membrane) outperformed the mictrofiltration (MF) membrane (i.e., tubular Al2O3 membrane) in terms of permeate quality. But, generally, the later yielded a greater membrane flux. In the case of BG wastewater by UF and EC/EF, the quality of permeate met the tap water standards in terms of water quality items analyzed. As for EDO and EDL further treated by UF and EC/EF, all the analyzed water quality items of permeate, except pH and total dissolved solids, met the tap water standards in Taiwan. Thus, more efforts have to be made to reclaim these two types of effluent. Finally, the components of membrane fouling were analyzed using resistances in series model for the tested water specimens. The results showed that generally the irreversible resistance component (Rirr) had a greater contribution to a better quality of permeate than that of the reversible resistance component (Rr). It was also found that the magnitude of Rirr of BG wastewater was greater than Rirr values of the other two effluents. This might explain why the quality of permeate of the former was better than the latter. The results further indicated that Rr increased more than Rirr as the operating time elapsed, resulting in a limited improvement of permeate quality even a longer treatment time was employed. To recover the membrane flux to its optimum, in this study the best time for backwashing of membrane was determined based on the time at which Rr was greater than Rirr. However, the flux recovery was found to be in the range of 60-77% as compared with the initial flux for a virgin membrane in treating new batch of water specimens. The fraction unable to recover by backwashing might be contributed by Rirr in the membrane pores. A further acid washing would resolve this problem.

Na atual emergência da construção de um discurso social requerido para a identidade de remanescentes de quilombos, este trabalho busca refletir sobre as resistências dos trabalhadores escravizados na região mineradora do rio Guaporé, na Capitania de Mato Grosso, entre a fundação de Vila Bela da Santíssima Trindade em 1752 e anos iniciais do século 19, tendo como suporte fontes arqueológicas, documentais escritas e de memória. Propõe evidenciar as bases materiais para a construção de táticas de resistência e contraponto à estrutura repressora administrativa/senhorial escravista, e a partir delas o surgimento de quilombos como sua forma mais elaborada. Traz ainda uma possível interpretação dessa construção social em confluência com a invenção de uma economia mineradora paralela ao sistema colonial ao estabelecer os assentamentos quilombolas sobre terrenos auríferos. Ao final, sugere a existência na cidade de um reordenamento interno de falas autorizadas e ainda o surgimento de discursos a reconstruir um passado quilombola necessário. / The master\'s dissertation aims at discussing resistance strategies by enslaved workers, at the mining areas at Mato Grosso, since 1752 until the beginning of the 19th.c. The dissertation uses archaeological evidence and documents. It also aims at exploring the material culture strategies used by slaves to resist oppression, during colonial rule. It also studies maroons as a main resistance strategy, relating those settlements to alternative mining practices, out of colonial control. Last but not least, the dissertation explores the ways discourses about the past contribute to reconstruct maroon past experiences.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Programa Institucional de CapacitaÃao Docente e TÃcnica / Este trabalho identifica, descreve e analisa narrativas de mulheres em situaÃÃo de violÃncia que denunciam seus agressores à PolÃcia, no espaÃo das Delegacias da Mulher. Adotando as teorizaÃÃes sobre o poder e a violÃncia formuladas por Hannah Arendt e Michel Foucault procuro discutir relaÃÃes de gÃnero marcadas pela violÃncia, escapando Ãs polarizaÃÃes entre homem-dominador x mulher dominada. Defendo que as mulheres nÃo sà reagem à violÃncia de mÃltiplas formas, mas produzem, atravÃs de suas resistÃncias â passivas e ativas â lugares de contra-dominaÃÃo, que algumas vezes podem assumir a forma de um âpoder situacionalâ. Essas resistÃncias se manifestam atravÃs de tÃticas cotidianas protagonizadas no espaÃo da vida privada e de estratÃgias de publicizaÃÃo no espaÃo pÃblico, quando se dirigem Ãs Delegacias da Mulher. Os conceitos de aÃÃes tÃticas e estratÃgias sÃo tomados, respectivamente de Michel De Certeau e Pierre Bourdieu. O trabalho tem como campo de anÃlise as Delegacias Especiais de ProteÃÃo à Mulher do Estado de Sergipe (DEPM). A anÃlise aborda o funcionamento das Delegacias da Mulher em duas cidades sergipanas: Aracaju e Itabaiana, relacionando suas prÃticas organizacionais ao campo da PolÃcia Civil. Procuro descrever e analisar rotinas, prÃticas institucionais, traÃos da cultura organizacional, valores, crenÃas e lÃgicas que circulam no campo de interseÃÃo entre a PolÃcia Civil, as Delegacias da Mulher e as expectativas das mulheres dirigidas a esta unidade policial. Procuro identificar suas demandas a partir de duas especificidades: casos que as mulheres pretendem a criminalizaÃÃo legal do agressor e casos em que buscam as Delegacias da Mulher visando a conciliaÃÃo, a mediaÃÃo de conflitos, garantias de direitos e proteÃÃo. A metodologia combina as abordagens qualitativa e quantitativa, tendo como fontes: 836 Boletins de OcorrÃncia registrados na dÃcada de 90, vinte e uma entrevistas com mulheres denunciantes, doze entrevistas com agentes policiais e delegadas e com seis representantes de movimentos sociais. Considero tambÃm duas experiÃncias de pesquisa-intervenÃÃo, realizadas por nstituiÃÃes nÃo policiais junto Ãs DEPMs, voltadas à formaÃÃo policial, com as quais tive contato, numa situaÃÃo de observaÃÃo participante: a primeira desenvolvida pela ComissÃo de Direitos Humanos da Universidade Federal de Sergipe e a segunda pelo MUSA (Mulher e SaÃde/ Instituto de SaÃde Coletiva da Universidade Federal da Bahia). A anÃlise das prÃticas da DEPM de Aracaju à delimitada por uma variÃvel temporal: antes e depois da criaÃÃo de Centro de Atendimento a Grupos VulnerÃveis, criado em 2004. Meu interesse recai sobre a constituiÃÃo do NÃcleo de MediaÃÃo de Conflitos, que funciona nesse complexo policial e atende à DEPM de Aracaju. Defendo que a adoÃÃo formal do instrumento de mediaÃÃo num espaÃo policial implica uma revisÃo da funÃÃo social das Delegacias da Mulher. Isso supÃe superar a concepÃÃo da atividade policial como prioritariamente investigativa e repressiva, e considerar que as aÃÃes de mediaÃÃo, assistÃncia e aconselhamento desenvolvidas pelas Delegacias da Mulher ao longo do PaÃs se constituem afirmativamente como aÃÃes prÃprias do fazer policial. / This work identifies, describes and analyzes talks of women under situation of violence who denounce their aggressors to the police, at the Womenâs Police Stations. Adopting conceptions about the power and the violence formulated by Hannah Arendt and Michel Foucault I try to talk about the gender relations marked by the violence and escaping to the polarizations between dominator-man x dominated-woman. I defend that the women not only react to the violence by many different forms, but produce, through their resistance - passive and active - places of anti-domination, that sometimes can assume what I call "situational power". These resistance behaviors are revealed through quotidian tactics at the private life space and through strategies of publicizing at the public space, when they go to the Womenâs Police Stations. The concepts of tactical actions and strategies are taken, respectively from Michel De Certeau and Pierre Bourdieu. The work used as research field the Sergipe State Police Stations for Woman Protection (DEPM). I try to describe and analyze routines, ritualized institutional practices, organizational culture traces, that circule on the field of intersection among the Civil Police, The Womenâs Police Stations and the expectations of the women who look for these offices. I try to identify their demands starting from two specialties: the cases where women look for the legal criminalization of their aggressor and the cases when they go to theses stations looking for conciliation, mediation of the conflicts,guarantee of rights and protection. The methodology combines qualitative and quantitative techniques, and have as sources of information: 836 Occurrence Bulletins registered in the 1990s, twenty-one interviews with women denouncers, twelve interviews with police agents and commission agents and with six social movementsâ representatives. I also use as sources two experiences of researchintervention, carried out by not policies institutions together with the Sergipe State Police Stations for Woman Protection, dedicated to police education, with whom I experienced two situations of participant observations: the first one developed by the Human Rights Commission of the Sergipe Federal University and second by the MUSA (Woman and Health - Group of Studies on Gender Research of the Bahia Federal University). The analysis is delimited by a temporal variable: before and after the creation of an Attendance Center for Vulnerable Groups, created in 2004, to which the Police Station of the Woman of Aracaju passed if to integrate. My interest falls again into particular on the constitution of the Nucleus of Mediation of Conflicts, that functions at the Womenâs Police Stations. I defend that the formal adoption of the instrument of mediation in a police space implies in a revision of the social function of the Womenâs Police Stations. This assumes to change the conception of the police activity as mainly investigative and repressive, and to consider that the actions of mediation, assistance and counseling developed by the Womenâs Police Stations are affirmatively constituted as proper actions of the Police.

Francisella tularensis est une bactérie à Gram négatif intracellulaire facultative, agent causal de la tularémie. Cette zoonose est induite principalement par deux sous espèces : F. tularensis subsp. tularensis (type A) et F. tularensis subsp. holarctica (type B) retrouvées respectivement en Amérique du Nord et dans tout l’hémisphère Nord. Cette seconde sous espèce, moins virulente que la première induit majoritairement des formes cliniques de sévérité moyenne à modérée dites ganglionnaires. Leur traitement est basé sur l’utilisation des antibiotiques de la classe des fluoroquinolones ou des tetracyclines, l’utilisation des aminosides étant réservée aux formes graves. Les adénopathies évoluent cependant souvent vers la suppuration et la chronicité (20 à 40% des cas), malgré l’administration d’un traitement antibiotique adapté.Les travaux réalisés visent à étudier l’hypothèse de l’émergence de la résistance bactérienne chez Francisella, expliquant ces échecs thérapeutiques. Ils sont basés sur le développement et l’étude d’un modèle d’évolution in vitro de la bactérie en présence de ciprofloxacine, une fluoroquinolone. Nos travaux ont confirmé la capacité de la bactérie à évoluer vers un haut niveau de résistance à ces antibiotiques, corrélée à l’accumulation de mutations dans les gènes codant pour les topoïsomérases de type II. De plus, nous avons observé la présence sur l’ensemble des souches de F. tularensis subsp. holarctica d’un niveau de résistance cliniquement significatif induit par des mutations modifiant la sous-unité GyrA de l’ADN gyrase sur les acides aminés en position 83 et 87. La recherche de ce marqueur dans des prélèvements de patient en échec thérapeutique suite à divers traitements antibiotiques s’est avérée infructueuse.Après avoir vérifié l’action de l’antibiotique sur les bactéries dans le compartiment intracellulaire (fibroblates), nous avons recherché les autres mutations induites lors de l’évolution de Francisella en présence de fluoroquinolones. Cette étude a permis l’implication de plusieurs systèmes de transports transmembranaires dans la résistance antibiotique. Nous avons également révélé l’existence d’une seconde cible majeure impliquée dans le métabolisme du fer de la bactérie. L’altération de cette cible (FupA/B) en plus d’être associée à une augmentation de la résistance aux fluoroquinolones est corrélée à une forte diminution de la capacité de la bactérie à se multiplier dans les cellules phagocytaires. / Francisella tularensis is a gram-negative facultative intracellular bacterium, causing tularemia. This zoonosis is mainly related to two subspecies: F. tularensis subsp. tularensis (type A) and F. tularensis subsp. holarctica (type B) in North America and throughout the Northern Hemisphere, respectively. Infections with this second subspecies, less virulent than the first one, predominantly induce glandular clinical forms of mild to moderate severity. Their treatment is based on antibiotherapy using a fluoroquinolone or a tetracycline. The use of aminoglycosides is reserved for severe clinical forms. The lymph nodes infection, however, often become chronic (20 to 40% of cases), despite administration of an appropriate antibiotic treatment.The aim of this study was to verify the hypothesis of the emergence of bacterial resistance in Francisella, which could explain treatment failures. It is based on the development and study of an in vitro evolutionary experiment of the bacterium in the presence of ciprofloxacin, a fluoroquinolone. Our work confirmed the bacterium's ability to evolve towards a high-level of resistance to fluoroquinolones, this evolution being correlated with the accumulation of mutations in the genes encoding for type II topoisomerases. In addition, we observed in all strains of F. tularensis subsp. holarctica resistant to fluoroquinolones at a clinically significant level, the presence of mutations altering the GyrA subunit of DNA gyrase at amino acids positions 83 and 87. The research of this marker in clinical samples from patients with treatment failure following appropriate antibiotic treatment was however unsuccessful.After checking the action of antibiotics on bacteria internalized in the intracellular compartment in fibroblast cells, we looked for other mutations induced during the evolution of Francisella to resistance to fluoroquinolones. This study unveiled the involvement of several transmembrane transport systems in antibiotic resistance. We also revealed the existence of a second major target involved in Francisella iron metabolism. The alteration of this target (FupA/B), in addition to being associated with an increase in fluoroquinolone resistance, is correlated with a sharp decrease in the ability of the bacteria to multiply in phagocytic cells.

L’étude des modifications phénotypiques et génomiques associées à l’adaptation des pathogènes aux résistances est une étape fondamentale pour mieux comprendre et anticiper le phénomène de contournement des résistances. Le nématode à kyste Globodera pallida est un important pathogène de la pomme de terre, vis-à-vis duquel un QTL majeur de résistance, GpaVvrn, a été identifié chez Solanum vernei. Cependant, la capacité des populations de G. pallida à s’adapter à cette résistance en quelques générations seulement a été mise en évidence par évolution expérimentale. Dans ce contexte, ce travail de thèse avait pour objectifs (1) d’étudier les traits d’histoire de vie du nématode impactés par l’adaptation, afin de tester l’existence éventuelle d’un coût de virulence, et (2) d’identifier les régions génomiques impliquées dans l’adaptation, par une approche originale combinant évolution expérimentale et scans génomiques sur des lignées virulentes et avirulentes. Contre toute attente, nous avons montré que l’adaptation à la résistance issue de S. vernei entraînait une augmentation de la fitness des individus virulents sur hôte sensible. Nous avons également pu identifier des régions génomiques candidates à l’adaptation à la résistance de la plante hôte, contenant des gènes codant pour des effecteurs, et notamment des SPRYSECs, connus chez les nématodes à kyste pour être impliqués dans la suppression des défenses des plantes mais aussi dans la virulence du nématode. À terme, ces résultats s’avéreront utiles pour la conception de stratégies durables de déploiement de variétés de pommes de terre résistantes. / Studying phenotypic and genomic modifications associated with pathogen adaptation to resistance is a crucial step to better understand and anticipate resistance breakdown. The cyst nematode Globodera pallida is an important pest of potato crops, for which a major resistance QTL, GpaVvrn, has been identified in Solanum vernei. However, the capability of G. pallida populations to adapt to this resistance in only few generations has been highlighted through experimental evolution. In this context, the purposes of this work were (1) to study the nematode life-history traits impacted by adaptation, in order to test for potential existence of a virulence cost, and (2) to identify genomic regions involved in adaptation, through an original approach combining experimental evolution and genome scans on virulent and avirulent lineages. Unexpectedly, we highlighted that adaptation to resistance from S. vernei leads to an increase of virulent individual’s fitness on susceptible host. We were also able to pinpoint candidate genomic regions to adaptation to host plant resistance, containing genes encoding effectors, and especially SPRYSECs, known in cyst nematodes to be involved in suppression of host defense but also in nematode virulence. These results will ultimately be useful in order to conceive sustainable strategies of use of potato resistant cultivars

The diploma thesis deals with the issue of braking trucks at different loads. The theoretical part defines the basic construction of trucks, truck brakes, the braking process and the factors that affect braking, braking deceleration, and legislative requirements for truck brakes. The practical part describes the course of experimental measurements, the use of the technique, the place of measurement, atmospheric conditions and used trucks. At the end of the work, based on experimental measurements, the obtained values of braking deceleration of trucks are evaluated.

This thesis deals with braking effect of the truck’s engine. The theoretical part introduces the reader to the basic construction of trucks, describes most using engine and defines the factors having a significant effect on engine braking. In the practical part the reader is familiar with the technique used in making the measurement and description of the vehicle chosen for the implementation of measurement. The result of the practical part is the values obtained by measurement including their interpretation contained in the conclusion.

This thesis is dealing with measuring the deceleration of lorries when they are braked by the engine. The weight of the vehicles given is bigger than 12 tons. The thesis can be divided into theoretical and practical part. In the theoretical part there are special presumptions to manage the given problem successfully. The stress is on the construction of lorries and on driving resistances which influence the process of deceleration a lot. The thesis also analyses the technical solution of each possibilities of braking and also the function of the gearbox. In the practical part the method of measuring is described. The measurement devices are also given through which the measurements were realized. The main part of this work is made by measured values of each lorries and the interpretation of measured values itself. The final evaluation of measured data are mentioned at the end of the thesis.

[ES] El cáncer de mama triple negativo representa el 10-20% de los casos de cáncer de mama. Este subtipo molecular se caracteriza por su gran agresividad y capacidad invasiva y se asocia a un mal pronóstico. La ausencia de receptores hormonales y de HER2 hace que la quimioterapia sea el principal tratamiento sistémico eficaz. Sin embargo, varias pacientes con cáncer de mama triple negativo recaen tras recibir quimioterapia. Por lo tanto, es crucial descifrar las características moleculares y buscar nuevas herramientas terapéuticas para este subtipo. En este sentido, los microRNAs (miRNAs) están desregulados en varios tipos de cáncer y emergen como potenciales moléculas pronósticas implicadas en procesos biológicos y en la respuesta a la quimioterapia. Esta tesis titulada "Papel de los microRNAs-449 en las características del cáncer de mama: de la regulación epigenética a la resistencia a la quimioterapia" se centra en el papel de la familia miRNA-449 (miRNA-449a, miRNA-449b-5p y miRNA-449c-5p) en la modulación de la agresividad del cáncer de mama y la respuesta a la quimioterapia. Este estudio aportó pruebas de la regulación a la baja de los miRNAs-449 en líneas celulares de cáncer de mama triple negativo y en pacientes, y sugirió la desacetilación de histonas de su región promotora como mecanismo inhibidor. En particular, se observó que las histonas desacetilasas HDAC1 y SIRT1 estaban reguladas al alza en las células de cáncer de mama triple negativo, y se sugirió su inhibición como mecanismo de inhibición. Los análisis in silico señalaron a ACSL4, una enzima activadora de ácidos grasos, como diana de miARNs-449. Esto concuerda con otros estudios que señalan una alteración del metabolismo de los lípidos como causa de la progresión del cáncer. Se observó una correlación inversa entre los miRNA-449 y la expresión de ACSL4 en líneas celulares de cáncer de mama triple negativo y en pacientes, y el ensayo de reportero de luciferasa confirmó por primera vez esta diana directa de ACSL4 por los miRNA-449a y miRNA-449b-5p. Además, la sobreexpresión del microRNA-449c-5p por sí sola también produjo una regulación a la baja de ACSL4, por lo que también se sugirió una relación indirecta a través de la modulación de moléculas desconocidas. La sobreexpresión de miRNAs-449 y la infraexpresión de ACSL4 inhibieron la proliferación celular, la migración al disminuir la capacidad de sufrir el proceso de transición epitelial-mesenquimal, y la formación de colonias al regular a la baja los marcadores de troncalidad. Estos resultados sugieren una inhibición miRNAs-449 de la agresividad del cáncer de mama a través de la regulación a la baja de ACSL4. Además, basándonos en la literatura previa y en los resultados publicados por nuestro laboratorio, se evaluó la implicación de los miRNAs-449 en la respuesta a la quimioterapia a través de esta nueva diana. Los miRNAs-449 fueron regulados a la baja en las células resistentes a la doxorrubicina. A su vez, se observó una sobreexpresión de ACSL4 en células resistentes a la doxorrubicina y en pacientes que recayeron tras un tratamiento con quimioterapia. El tratamiento posterior con doxorrubicina aumentó la expresión de miRNAs-449 pero disminuyó la de ACSL4 en las células sensibles a la doxorrubicina, pero no en las resistentes, sugiriendo así una implicación de miRNAs-449 y ACSL4 en la respuesta a la quimioterapia. En este estudio, observamos que la sobreexpresión de miRNAs-449 producía sensibilidad a la doxorrubicina a través de la regulación a la baja de ACSL4 mediante ensayos de viabilidad y apoptosis. Además, la inhibición de ACSL4 disminuyó la expresión de la bomba de extrusión de fármacos ABCG2, lo que condujo a un aumento de la acumulación de doxorrubicina en las células. La implicación del miRNAs-449 en la inhibición de la agresividad y la sensibilidad a la doxorrubicina sugiere su potencial uso como herramienta terapéutica en el cáncer de mama triple negativo. / [CA] El càncer de mama triple negatiu representa el 10-20% dels casos de càncer de mama. Aquest subtipus molecular es caracteritza per la seua gran agressivitat i capacitat invasiva i s'associa a un mal pronòstic. L'absència de receptors hormonals i d'HER2 fa que la quimioteràpia siga el principal tractament sistèmic eficaç. No obstant això, diverses pacients amb càncer de mama triple negatiu recauen després de rebre quimioteràpia. Per tant, és crucial desxifrar les característiques moleculars i buscar noves eines terapèutiques per a aquest subtipus. En aquest sentit, els microRNAs (miRNAs) estan desregulats en diversos tipus de càncer i emergeixen com a potencials molècules pronósticas implicades en processos biològics i en la resposta a la quimioteràpia. Aquesta tesi titulada "Paper dels microRNAs-449 en les característiques del càncer de mama: de la regulació epigenètica a la resistència a la quimioteràpia" se centra en el paper de la família miRNA-449 (miRNA-449a, miRNA-449b-5p i miRNA-449c-5p) en la modulació de l'agressivitat del càncer de mama i la resposta a la quimioteràpia. Aquest estudi va aportar proves de la regulació a la baixa dels miRNAs-449 en línies cel·lulars de càncer de mama triple negatiu i en pacients, i va suggerir la *desacetilación d'histones de la seua regió promotora com a mecanisme inhibidor. En particular, es va observar que les histones desacetilasas HDAC1 i SIRT1 estaven regulades a l'alça en les cèl·lules de càncer de mama triple negatiu, i es va suggerir la seua inhibició com a mecanisme d'inhibició. Les anàlisis in silico van assenyalar a ACSL4, un enzim activador d'àcids grassos, com a diana de miARNs-449. Això concorda amb altres estudis que assenyalen una alteració del metabolisme dels lípids com a causa de la progressió del càncer. Es va observar una correlació inversa entre els miRNA-449 i l'expressió d'ACSL4 en línies cel·lulars de càncer de mama triple negatiu i en pacients, i l'assaig de reporter de luciferasa va confirmar per primera vegada aquesta diana directa d'ACSL4 pels miRNA-449a i miRNA-449b-5p. A més, la sobreexpressió del miRNA-449c-5p per si sola també va produir una regulació a la baixa d'ACSL4, per la qual cosa també es va suggerir una relació indirecta a través de la modulació de molècules desconegudes. La sobreexpressió de miRNAs-449 i la infraexpressió d'ACSL4 van inhibir la proliferació cel·lular, la migració en disminuir la capacitat de patir el procés de transició epitelial-mesenquimal, i la formació de colònies en regular a la baixa els marcadors de troncalitat. Aquests resultats suggereixen una inhibició de l'agressivitat del càncer de mama a través de la regulació a la baixa d'ACSL4. A més, basant-nos en la literatura prèvia i en els resultats publicats pel nostre laboratori, es va avaluar la implicació dels miRNAs-449 en la resposta a la quimioteràpia a través d'aquesta nova diana. Els miRNAs-449 van ser regulats a la baixa en les cèl·lules resistents a la doxorubicina. Al seu torn, es va observar una sobreexpressió d'ACSL4 en cèl·lules resistents a la doxorubicina i en pacients que van recaure després d'un tractament amb quimioteràpia. El tractament posterior amb doxorubicina va augmentar l'expressió de micRNAs-449 però va disminuir la d'ACSL4 en les cèl·lules sensibles a la doxorubicina, però no en les resistents, suggerint així una implicació dels miRNAs-449 i ACSL4 en la resposta a la quimioteràpia. En aquest estudi, observem que la sobreexpressió dels miRNAs-449 produïa sensibilitat a la doxorubicina a través de la regulació a la baixa d'ACSL4 mitjançant assajos de viabilitat i apoptosi. A més, la inhibició d'ACSL4 va disminuir l'expressió de la bomba d'extrusió de fàrmacs ABCG2, la qual cosa va conduir a un augment de l'acumulació de doxorubicina en les cèl·lules. La implicació dels miRNAs-449 en la inhibició de l'agressivitat i la sensibilitat a la doxorubicina suggereix el seu potencial ús com a eina terapèutica en el càncer de mama triple negatiu. / [EN] Triple-negative breast cancer accounts for 10-20% of breast cancer cases. This molecular subtype is characterized by its highly aggressive and invasive capacity being associated with a bad prognosis. The lack of hormone and HER2 receptors makes chemotherapy the main systemic effective treatment. However, several triple-negative breast cancer patients relapse after receiving chemotherapy. Therefore, deciphering the molecular characteristics and searching for new therapeutic tools for this subtype is crucial. In this sense, microRNAs (miRNAs) are found dysregulated in several cancer types and emerge as potential prognostic molecules involved in biological processes and chemotherapy response. This thesis entitled "Role of microRNAs-449 in breast cancer features: From epigenetic regulation to chemotherapy resistance" is focused on the role of the miRNA-449 (miRNA-449a, miRNA-449b-5p, and miRNA-449c-5p) family in the modulation of breast cancer aggressiveness and chemotherapy response. This study provided evidence of microRNAs-449 downregulation in triple-negative breast cancer cell lines and patients and suggested histone deacetylation of its promoter region as an inhibitor mechanism. Particularly, the histone deacetylases HDAC1 and SIRT1 were found upregulated in triple-negative breast cancer cells, and their genetic and chemical inhibition increased microRNAs-449 expression. In addition, a negative feedback loop modulation between miRNAs-449 and HDAC1/SIRT1 was observed, thus contributing to the homeostasis or tumoral phenotype of cells. In silico analyses pointed out ACSL4, a fatty acid-activating enzyme, as target of miRNAs-449. This is in concordance with other studies that pointed out an altered lipid metabolism to sustain cancer progression. An inverse correlation between microRNAs-449 and ACSL4 expression was observed in triple-negative breast cancer cell lines and patients, and luciferase reporter assay confirmed this ACSL4 direct targeting by miRNA-449a and miRNA-449b-5p for the first time. Moreover, the microRNA-449c-5p overexpression alone also produced an ACSL4 downregulation, so an indirect relationship was also suggested through the modulation of unknown molecules. MiRNAs-449 overexpression and ACSL4 knockdown inhibited cell proliferation, migration by diminishing the ability to undergo the epithelial-mesenchymal transition process, and colony formation by downregulating markers of stemness. These results suggested a microRNAs-449 inhibition of breast cancer aggressiveness through ACSL4 downregulation. Furthermore, based on previous literature and published results by our laboratory, a miRNAs-449 implication in chemotherapy response was evaluated through this novel target. MiRNAs-449 were downregulated in doxorubicin-resistant cells. In turn, ACSL4 overexpression was observed in doxorubicin-resistant cells and patients who relapsed after chemotherapy-containing treatment. Subsequent doxorubicin treatment increased miRNAs-449 but decreased ACSL4 expression in doxorubicin-sensitive, but not in resistant cells, thus suggesting a miRNAs-449 and ACSL4 implication in chemotherapy response. In this study, we observed that miRNAs-449 overexpression produced doxorubicin sensitivity through ACSL4 downregulation by viability and apoptosis assay. In addition, ACSL4 inhibition decreased the drug extrusion pump ABCG2's expression, leading to an increased doxorubicin accumulation in cells. The involvement of miRNAs-449 in the inhibition of aggressiveness and sensitivity to doxorubicin suggests its potential use as a therapeutic tool in triple-negative breast cancer. / Torres Ruiz, S. (2023). Papel de la familia de microRNAs-449 y el gen CDC20B en la respuesta a tratamientos en cáncer de mama: organoides y cultivos primarios como modelos tumorales [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/198846