• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 292
  • 104
  • 64
  • 43
  • 19
  • 18
  • 14
  • 13
  • 11
  • 9
  • 5
  • 3
  • 2
  • 2
  • 2
  • Tagged with
  • 757
  • 757
  • 195
  • 159
  • 71
  • 70
  • 70
  • 67
  • 60
  • 59
  • 58
  • 53
  • 50
  • 47
  • 47
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
511

Identificação e desenvolvimento de biomarcador para câncer de pulmão de não-pequenas células : o potencial prognóstico da cofilina-1

Müller, Carolina Beatriz January 2012 (has links)
O câncer de pulmão é responsável por aproximadamente 13% do total de casos de neoplasias malignas e por cerca de 1.4 milhões de mortes por ano em todo mundo. Esta neoplasia apresenta-se sob dois principais subtipos: câncer de pulmão de pequenas células (CPPC) e câncer de pulmão de não-pequenas células (CPNPC). Cerca de 85% dos casos de câncer de pulmão são do tipo CPNPC. Os sinais e sintomas são secundários ao crescimento do tumor primário, ao comprometimento lobo-regional, à disseminação à distância, ou são secundários às síndromes paraneoplásicas. Essas características refletem diretamente sobre as taxas de mortalidade; de cada 100 novos casos, 80 são inoperáveis e a maioria morre dentro de 3 anos. Isso significa que, apesar dos diversos avanços no diagnóstico e tratamento, o prognóstico do câncer de pulmão permanece sendo extremamente ruim, com sobrevida média de 10 meses, e cumulativa total em 5 anos de aproximadamente 12%. Atualmente, o prognóstico e a decisão terapêutica de pacientes com câncer de pulmão é baseada no TNM, Embora esse seja o procedimento considerado padrãoouro entre os profissionais de saúde, ele não leva em consideração características biológicas do tumor. Nesse contexto, a identificação de biomarcadores para câncer pode agregar importantes informações ao já estabelecido sistema TNM e resultar em tratamentos mais eficientes e em menores taxas de mortalidade. Existem 5 fases distintas que conceitualizam o desenvolvimento de um biomarcador tumoral. Através dessas fases consecutivas, é possível que se desenvolvam ferramentas úteis para triagem populacional, capazes de serem implementadas na rotina clínica para predição de desfecho do paciente, resposta terapêutica e monitoramento da doença. O presente projeto avaliou o valor prognóstico dos principais genes citados na literatura como potenciais biomarcadores para CPNPC, e verificou-se que nenhum deles apresentou significância na correlação estatística que indica poder prognóstico. Além disso, identificamos e validamos o papel prognóstico da cofilina-1 por meio de dados de microarranjo e quantificação de seu imunoconteúdo em biópsias de CPNPC. Para tanto, fizemos uso de meta-análise de bancos de dados e análise densitométrica das reações imuno-histoquímicas, seguida de correlação com dados de grau de diferenciação tumoral, classificação histológica, sexo, idade e desfecho relativo a cada caso. Além disso, desenvolvemos um método de baixo custo, fácil execução e ampla aplicação e reproducibilidade, capaz de quantificar a proteína em amostras biológicas, com potencial para ser implementado na rotina clínica e aplicamos esse método em uma coorte restrospectiva de CPNPC. Confirmamos assim o papel prognóstico da cofilina-1. Estes achados seguem a lógica das fases de desenvolvimento de um biomarcador e representam um grande passo no seu processo de validação. / Lung cancer accounts for approximately 13% of all malignant tumor cases and for about 1.4 million deaths per year worldwide. This cancer has two main subtypes: Small Cell Lung Cancer (SCLC) and Non-Small Cell Lung Cancer (NSCLC). About 85% of cases of lung cancer are NSCLC type. The signs and symptoms are secondary to the primary tumor growth, to regional lobe commitment and distant spread, or are secondary to paraneoplastic syndromes. These features reflect directly on mortality rates; 80 in every 100 new cases are inoperable and most die within 3 years. This means that, despite many advances in diagnosis treatment, the prognosis of lung cancer remains extremely poor, with median survival of 10 months, and total cumulative survival in 5-year of approximately 12%. Currently, prognosis and therapeutic decisions in patients with lung cancer is based on TNM. Although this procedure is considered gold standard among health professionals, it does not take into account the biological characteristics of the tumor. In this context, the identification of cancer biomarkers may add important information to the already established TNM system and result in better treatments and lower mortality rates. There are five distinct phases that conceptualize a tumor biomarker development of. Through these successive phases, it is possible to develop useful tools for population screening, capable of implementation in clinical practice for prediction of patient outcome, therapeutic response and disease monitoring. This project evaluated the prognostic value of major genes mentioned in literature as potential biomarkers for NSCLC and found that none of them showed statistical significance in the correlation that indicates prognostic power. It also identified and validated the prognostic role of cofilin-1 by microarray data and quantification of their immunocontent in biopsies of NSCLC. For this purpose, we used data metaanalysis and immunohistochemical reactions densitometric analysis, followed by correlation with data from tumor grade, histological classification, sex, age and outcome for each case. In addition, we developed a low-cost protocol, of easy implementation and wide application and reproducibility, able to quantify the protein in biological samples, with the potential to be implemented in clinical practice. We applied this method in a retrospective cohort of NSCLC and confirm the prognostic role of cofilin-1. These findings follow the logical phases of biomarker development and represent a major step in its validation process.
512

Análise da medida da circunferência muscular do braço como fator prognóstico em carcinoma pulmonar não-pequenas células metastático

Tartari, Rafaela Festugatto January 2012 (has links)
INTRODUÇÃO: Pacientes com câncer de pulmão metastático compreendem uma população bastante heterogênea. A média de sobrevida é de 8-10 meses, porém 25-30% dos pacientes morrem dentro de 6 meses e aproximadamente 20% sobrevivem mais que 18 meses após a disseminação da neoplasia. Por isso, além da Escala de Karnosfky (KPS) e ECOG, outros fatores são necessários para estimar o prognóstico destes pacientes, proporcionando assim uma melhor programação da terapia antitumoral e qualidade de vida, além da possibilidade de estratificar grupos para avaliação de novas drogas. A circunferência muscular do braço (CMB) estima a reserva de proteína corporal, sendo um indicador precoce de depleção nutricional. É uma medida objetiva, rápida, de baixo custo e nãoinvasiva, em comparação com outras investigações bioquímicas. OBJETIVO: Avaliar a CMB como fator prognóstico em pacientes com câncer de pulmão metastático. MÉTODOS: Foi realizada análise de sobrevida em 56 pacientes com câncer de pulmão não pequenas células (CPNPC), em estadio IV, com mais de uma metástase, os quais tiveram suas CMBs mensuradas logo após o diagnóstico. Os resultados da CMB foram classificados de acordo com o Percentual de Adequação, ajustado por sexo e idade. Os pacientes foram caracterizados como eutróficos (CMB > 90%) ou depletados (CMB <90%), e suas sobrevidas foram comparadas. RESULTADOS: A amostra apresentou idade média de 63 anos (47-80). A média do Percentual de Adequação foi de 89% (66-122), apresentando depleção 55% dos pacientes. A sobrevida média foi de 6,2 meses (95% IC:5,1-7,3). Nos pacientes eutróficos, a média de sobrevida foi 10,2 meses (95% IC: 9,2-11,1), e nos depletados foi de 5 meses (95% IC: 4,2-5,8), apresentando diferença estatisticamente significativa entre os dois grupos (P < 0.001). Esta diferença permaneceu significante na análise multivariada (P<0,001, análise de COX) com as co-variáveis KPS, idade, sexo, quimioterapia. CONCLUSÃO: Avaliação da CMB é um forte fator prognóstico em pacientes com CPNPC. Neste estudo, os pacientes depletados, com Percentual de Adequação da CMB < 90% tiveram baixa sobrevida global. / INTRODUCTION: Stage IV patients with lung cancer comprises a very heterogenous population. The median survival is 8-10 months but 25-30% of patients dies within 6 months and about 20% of patients survive longer than 18 months after metastatic spread. Strong prognostic factors other than karnofsky status or ECOG status are still needed to even better estimate the prognosis of these patients and to help in the decision making process of planning standard treatment options or to stratify patients for inclusion in innovative treatment trials. The mid arm muscular circunference (MAMC) is a bedside anthropometric measurement that estimates corporal protein reserve which is an early indicator of nutritional depletion. It has the advantages of being objective, rapid, repeatable, non-invasive and in-expensive in comparison to various biochemical investigations. OBJECTIVE: Our purpose was to evaluate MAMC as a potential prognostic factor in patients with metastatic lung cancer. METHODS: A prospective survival analysis of 56 non-selected, consecutive patients (29 women) with metastatic non small lung cancer who had their MAMC measured in the first nutritional evaluation. The MAMC results were expressed as a percentage of the expected reference values adjusted for sex and age. Patients were categorized as normal (MAMC > 90%) or depleted (AMC < 90%) and their overall survival was compared. RESULTS: The mean age of patients was 63 years (range 47 - 80). The mean MAMC percentage of the expected value was 89 (range 66 – 122), with 55% of our patients (31) classified as depleted by MAMC measurement. Median overall survival of all patients was 6,2 months (95% CI: 5,1 – 7,3). In the group of patients with normal MAMC, median overall survival was 10,2 months (95% CI: 9.2 – 11.1). In patients classified as depleted, the mean overall survival was 5.0 months (95% CI: 4.2 – 5.8). The overall survival differences between these two groups defined by the MAMC (normal x depleted), was highly statistically significant (P < 0.001 by the logrank test, HR=0.21, 95%CI: 0.09 – 0.5 for patients with normal MAMC). These differences remained significant in a multivariated analysis (P<0.001 by the Cox proportional hazards method), with the Karnofsky status, age, chemotherapy and sex as covariates. CONCLUSIONS: One measurement of mid arm muscular circumference in the first nutritional evaluation is a strong prognostic factor in patients with metastatic non small cell lung cancer. In our series, patients with <90% of expected MAMC had poor overall survival.
513

Atividade citotóxica do óleo essencial de Lippia spp. frente a células da linhagem A549 de carcinoma de pulmão humano / Cytotoxic activity of the essential oil of Lippia spp. facing cells of A549 line of human lung carcinoma

Almeida, Patrícia de Oliveira Santos 17 April 2016 (has links)
The lung carcinomas stand out as a major public health problem, therefore, are among the leading causes of cancer death worldwide. They are classified into two major histological groups: small cell lung carcinome (SCLC) and non small cell lung carcinoma non (NSCLC). In the search for novel therapies, many natural products derived from plants and other organisms has been studied for use as a source for the development of chemotherapeutic agents used in the treatment of various cancers, including carcinomas of the lung. In this context, the essential oils is part of medicinal plants produced by such as the genus Lippia that have many therapeutic properties, among them, antimicrobial, anti-inflammatory and antiproliferative. This study proposes to investigate the cytotoxic activity of essential oils of different species and genotypes of the genus Lippia plants. the Active Germplasm Bank of the Federal University of Sergipe (UFS) located at the Experimental Farm "Rural Campus of the UFS," which have varied chemical composition. For this A549 cells (lung carcinoma) were treated with increasing concentrations (20-160 / mL) essential oils Lippia gracilis (genotypes 106 and 110) of Lippia alba (genotypes 13:57) and Lippia sidoides (genotypes 102 and 104) during the 24 hour interval. Cytotoxicity of these essential oils was determined by the MTT colorimetric method. The absorbance values obtained in the treatments were normalized to the untreated cells and used to calculate IC50 values by regression analysis. IC50 values of 75.42 and 158.6 ug / ml were obtained for the LG-106 and LG-110 genotypes, respectively. For LS-102 and LS-104 genotypes IC50 were respectively 97.93 and 150.70 mg / mL and LA-13 and LA-57 genotypes these values were 86.14 and 70.34 mg / mL . Microscopic analysis of cells stained by hematoxylin-eosin showed morphological changes, including condensation of cytoplasm, chromatin condensation and nuclear fragmentation induced by all genotypes. These results suggest that the cytotoxic activity presented by the essential oils of Lippia on A549 lineage cells involves induction of programmed cell death. Therefore, it is concluded that these oils represent a promising source compounds for the development of new anti-tumor therapies. / Os carcinomas de pulmão destacam-se como um grave problema de saúde pública, pois, encontram-se entre as principais causas de morte por câncer no mundo. São classificados em dois principais grupos histológicos: carcinoma de pulmão de células pequenas (CPCP) e carcinoma de pulmão de células não pequenas (CPCNP). Na busca por terapias inovadoras, diversos produtos naturais derivados de plantas e outros organismos têm sido estudados para utilização como fonte para o desenvolvimento de quimioterápicos empregados no tratamento de diversos tipos de câncer, inclusive dos carcinomas de pulmão. Nesse contexto, insere-se os óleos essenciais produzidos por plantas medicinais como as do gênero Lippia que apresentam diversas propriedades terapêuticas, dentre elas, atividade antimicrobiana, antinflamatória e antiproliferativa. O presente trabalho propõe a investigação da atividade citotóxica dos óleos essenciais de diferentes espécies e genótipos de plantas do gênero Lippia. do Banco Ativo de Germoplasma da Universidade Federal de Sergipe (UFS), localizado na Fazenda Experimental “Campus Rural da UFS”, que apresentam variada composição química. Para isso as células A549 (Carcinoma de pulmão), foram tratadas com concentrações crescentes (20 a 160 μg/mL) de óleos essenciais de Lippia gracilis (genótipos 106 e 110), de Lippia alba (genótipos 13 e 57) e Lippia sidoides (genótipos 102 e 104) durante o intervalo de 24 horas. A citotoxicidade destes óleos essenciais foi determinada pelo método colorimétrico do MTT. Os valores das absorbâncias obtidas nos tratamentos foram normalizados com os das células não tratadas e utilizados para calcular os valores de IC por análise de regressão. Valores de IC50 de 75,42 e 158,6 μg/mL foram obtidos para os genótipos LG-106 e LG-110, respectivamente. Para os genótipos LS-102 e LS-104 as IC50 foram, respectivamente, 97,93 e 150,70 μg/mL e para os genótipos LA-13 e LA-57 estes valores foram 86,14 e 70,34 μg/mL. A análise microscópica das células coradas por hematoxilina-eosina revelou alterações morfológicas incluindo condensação do citoplasma, condensação da cromatina e a fragmentação nuclear induzidas por todos os genótipos avaliados. Estes resultados sugerem que atividade citotóxica apresentada pelos óleos essenciais de Lippia sobre células da linhagem A549 envolve a indução de morte celular programada. Com isso, conclui-se que tais óleos representam uma fonte promissora de compostos para o desenvolvimento de novas terapias antitumorais. / São Cristóvão, SE
514

O papel da quinase Aurora A na biologia das células iniciadoras de turmor pulmonares com mutação em KRAS / The role of Aurora A kinase in the biology of lung tumor initiating cells with KRAS mutations

Luiza Coimbra Scalabrini 06 December 2016 (has links)
Mutações ativadoras no gene KRAS são prevalentes em cancer de pulmão e a as vias de sinalização de RAS estão aumentadas em células iniciadoras de tumor (CITs), que são definidas como células autorrenováveis capazes de iniciar a formação tumoral, sustentar o crescimento tumoral e promover a disseminação tumoral. Entretanto, terapias direcionadas a RAS não foram efetivas até hoje e a identificação de alvos de KRAS que contribuam para o fenótipo oncogênico é necessária. Como a quinase Aurora A (AURKA) já foi implicada, tanto na oncogênese induzida por KRAS, quanto em promover a função das CITs, nós hipotetizamos que a inibição das vias de AURKA seria detrimental para a função de CITs pulmonares portadoras de KRAS oncogênica, desta forma diminuindo o comportamento maligno do câncer de pulmão. Para avaliar a função das CITs, nós usamos ensaios de crescimento de tumoresferas que permitem o crescimento seletivo de CITs in vitro. As linhagens pulmonares positivas para KRAS H358 e A549 formaram tumoresferas em cultura de baixa aderência e, quando comparadas às linhagens parentais, às células oriundas de tumoresferas apresentaram maior capacidade clonogênica in vitro e maior tumorigenicidade in vivo. Além disso, uma análise por qPCR revelou que as células oriundas de tumoresferas possuem expressão aumentada de fatores de células tronco, uma característica de CITs. Em seguida, nós inibimos a AURKA nas linhagens pulmonares positivas para KRAS H358 e A549 por interferência de RNA (RNAi) ou com um inibidor das quinases Aurora (AI II). A inibição de AURKA diminuiu a formação de tumoresferas e o crescimento destas em culturas seriadas, além de reduzir a capacidade clonogênica das células oriundas de tumoresferas. Estes resultados indicam que a AURKA é importante para a autorrenovação e a oncogenicidade de CITs, e que a AURKA induz o fenótipo tronco-tumoral, o que é corroborado pelo achado de que a inibição de AURKA nas tumoresferas reduz a expressão de fatores de célula tronco. Um destes fatores regulados por AURKA é o marcador de superfície de célula tronco CD24. De fato, quando comparadas às células cultivadas de forma aderente, as células oriundas de tumoresferas apresentam maior número de células positivas para CD24 (CD24+) e estes números são reduzidos pelo tratamento com AI II. Finalmente, nós purificamos células H358 CD24+ por citometria de fluxo e mostramos que, quando comparadas às células negativas para CD24, as células CD24+ apresentam maior capacidade de formar tumoresferas em culturas seriadas, e o tratamento com AI II inibe preferencialmente a capacidade de células CD24+ de formarem tumoresferas. Nossos resultados sugerem que uma terapia baseada na inibição de AURKA pode reduzir o número e função de CITs pulmonares portadoras de KRAS oncogênica e, portanto, pode representar uma estratégia terapêutica atraente para reduzir a recidiva e metástase no câncer de pulmão induzido por KRAS. / Activating mutations in KRAS are prevalent in lung cancer and RAS sinaling is enhanced in cancer initiating cells (CICs), which are defined as self-renewing tumor cells able to initiate tumor formation, sustain tumor growth and drive tumor dissemination. However, therapies targeted to oncogenic RAS have been ineffective to date and identification of KRAS targets that impinge on the oncogenic phenotype is warranted. Because Aurora kinase A (AURKA) has been implicated both in RAS oncogenesis and in promoting CIC function, we hypothesized that targeting AURKA pathways would impair KRAS-positive lung CIC function, thereby decreasing lung cancer malignant behavior. To evaluate CIC function, we used tumorsphere assays that allow selective growth of CICs in vitro. KRAS positive lung cancer H358 and A549 cells formed tumorspheres under low attachment conditions, and, when compared to the parental cell lines, sphere-forming cells had increased clonogenic ability in vitro and increased tumorigenicity in vivo. In addition, qPCR analysis revealed that tumorsphere cells displayed increased expression of stem cell factors, a hallmark of CICs. Next, we targeted AURKA in KRAS positive lung cancer H358 and A549 cells by RNA interference (RNAi) or with an Aurora inhibitor (AI II). AURKA targeting decreased tumorsphere formation and growth in serial cultures and reduced clonogenic growth of tumorsphere-forming cells. These results indicate that AURKA is important for CIC selfrenewal and oncogenicity and that AURKA induces a CIC phenotype, which is further underscored by the finding that AURKA targeting in tumorspheres decreases expression of stem cell factors. One such factor shown to be regulated by AURKA is the stem cell surface marker CD24. In fact, when compared to adherent cultures, A549 and H358 tumorspheres display increased numbers of CD24-positive (CD24+) cells and these numbers are reduced by AI II treatment. Finally we purified H358 CD24+cells by flow cytometry and showed that, when compared to CD24-negative cells, CD24+ cells have increased ability to form tumorspheres in serial cultures, and AI II treatment preferentially reduced the ability of CD24+ cells to form tumorspheres. Our results suggest that AURKA inhibition therapy can reduce the number and function of KRAS-positive lung CICs, and, therefore might be an attractive therapeutic strategy to reduce recurrence and metastasis in KRAS-induced lung cancer.
515

Avaliação do efeito antitumoral in vitro de nanocápsulas de núcleo lipídico de tretinoína sobre células de adenocarcinoma de pulmão, linhagem A549 / In Vitro Antitumor Activity of Tretinoin-Loaded Lipid-Core Nanocapsules on human lung adenocarcinoma cell line (A549)

Schultze, Eduarda 26 February 2013 (has links)
Made available in DSpace on 2014-08-20T13:32:47Z (GMT). No. of bitstreams: 1 dissertacao_eduarda_schultze.pdf: 1903452 bytes, checksum: 1fd6d0e0478c9c31687ae8d7882532ea (MD5) Previous issue date: 2013-02-26 / Retinoid derivatives and analogs have been widely studied as antitumor agents due to their effects on cell proliferation and differentiation. Tretinoin (TT), also known as retinoic acid is a retinoid derivative that has been used as an adjuvant in the treatment of acute promyelocytic leukemia with excellent rates of remission. This compound has antiproliferative activity in various tumor types. However, non small cell lung cancer in general exhibit strong resistance to the effects of TT, which may be related to the deficiency in the cellular up-take of TT in that cell type. A strategy to enhance the antiproliferative activity of TT is to increase the cellular internalization of the compound through carriers such as liposomes or other vesicles or nanospheres or nanocapsules. Here we evaluated TT lipid-core nanocapsules (TT-LCNC) for their power to inhibit growth, induce apoptosis and interfere with the cell cycle of lung adenocarcinoma, A549 cell line, which is resistant to treatment with TT. The results showed that TT-LCNC was able to overcome the cellular resistance to treatment with TT, reducing cell viability and inducing apoptosis, upregulation of P21 and cell cycle arrest in G1 phase. / Derivados e análogos retinóides têm sido largamente estudados como agentes antitumorais devido a seus efeitos sobre a proliferação e diferenciação celular. Tretinoína (TT), também conhecida como ácido retinóico é um derivado retinóide que tem sido usado como adjuvante no tratamento de leucemia promielocítica aguda com excelentes índices de remissão da doença. Este composto exerce atividade antiproliferativa em diversos tipos de tumores. Entretanto, células de adenocarcinoma de pulmão humano em geral exibem uma forte resistência aos efeitos da tretinoína, a qual pode estar relacionada com a deficiência na internalização celular de tretinoína nesse tipo de célula. Uma estratégia para aumentar a atividade antiproliferativa de tretinoína é aumentar a captação celular do composto através de carreadores como lipossomas ou outras vesículas como nanocápsulas ou nanoesferas. Neste trabalho nanocápsulas de núcleo lipídico contendo tretinoína (TT-LCNC) foram avaliadas quanto ao seu potencial de inibir o crescimento, induzir a apoptose e interferir com o ciclo celular de células de adenocarcinoma de pulmão, linhagem A549, resistentes ao tratamento com TT livre. Os resultados demonstraram que TT-LCNC foi capaz de superar a resistência celular ao tratamento com TT, reduzindo a viabilidade celular e induzindo apoptose, superexpressão de P21 e parada do ciclo celular em G1.
516

Caractérisation des réseaux d’interactions protéiques associés aux mutations oncogéniques principales retrouvées dans le cancer du poumon non à petites cellules / New insights and characterisation of the dynamic protein interaction landscape driven by oncogene mutations in non-small cell lung cancer

Beganton, Benoît 29 November 2017 (has links)
Le cancer du poumon est la première cause de mortalité liée au cancer en France et dans le monde. Il s’agit d’un cancer de mauvais pronostique, diagnostiqué généralement aux stades tardifs III ou IV et avec une survie à 5 ans faible, respectivement de 6 et 1%. Ce cancer comprend différents types histologiques, parmi lesquels les adénocarcinomes sont les plus fréquents et comptent pour 40% des diagnostics. L’analyse génétique par séquençage des tumeurs des patients en stade IV permet de mettre en évidence des mutations récurrentes, et généralement mutuellement exclusives, au niveau des gènes KRAS, EGFR, BRAF et ALK. L’identification de ces mutations permet dans le cadre de tests compagnons de décider de l’éligibilité du patient aux thérapies ciblées lorsqu’elles sont disponibles.Bien que ces thérapies ciblées représentent une véritable révolution dans la prise en charge des patients, une majorité de patients ne peuvent bénéficier de ces traitements car ils ne présentent pas au niveau tumoral de mutation activatrices actionnables (absence de mutation EGFR, BRAF et ALK, présence d’une mutation KRAS…). De plus, dans l’éventualité où ils peuvent être traités par une molécule orale, le bénéfice observé reste malheureusement de courte durée et tous finiront à terme par échapper au traitement, c’est le cas par exemple lors de mutations de l’EGFR.Ainsi, afin de mieux comprendre quels sont les mécanismes moléculaires associés aux phénomènes de résistances thérapeutiques observés en clinique, et dans l’objectif de proposer de nouvelles voies thérapeutiques pour les patients non éligibles aux thérapies ciblées, j’ai étudié, au niveau protéique, l’impact des mutations sur les réseaux d’interactions protéiques en utilisant la technique du BioID (proximity-dependent biotinylation identification). Plus particulièrement, je me suis intéressé aux mutations activatrices de l’EGFR, KRAS, BRAF et ALK. Les protéines de la famille RAS (HRAS, NRAS, KRAS) étant mutées dans plus de 30% des cancers, je me suis également intéressé aux réseaux d’interactions protéiques portés par ces trois isoformes afin de mettre en évidence des interactions protéiques spécifiques à l’isoforme KRAS.Au cours de ma thèse, j’ai montré que les réseaux d’interaction caractérisés par le BioID sont bien plus denses que ceux obtenus par la technique plus conventionnelle de purification par affinité, et qu’ils permettent de mettre en évidence des interacteurs spécifiquement dérégulés par l’apparition de mutations activatrices. Par ailleurs les modèles cellulaires HEK293 (cellules humaines embryonnaires de rein) et BEAS2B (cellules pulmonaires d’origine non-cancéreuses) ont montré un fort recouvrement des interacteurs identifiés, ce qui suggère que la stratégie employée est pertinente pour identifier des interacteurs spécifiques de mutations. Ce travail de thèse a permis d’identifier une série de plusieurs interacteurs spécifiques des formes mutante de KRAS, d’EGFR, de BRAF, de NRAS et de la fusion EML4-ALK. Treize interacteurs spécifiques de la forme mutée de KRAS ont été validés fonctionnellement dans des modèles cellulaires de cancers du poumon. Enfin, en utilisant les données de BioID, un modèle préliminaire de résistance de l’EGFR aux thérapies ciblées a pu être élaboré, lequel fait apparaitre les protéines CBL et IGF2R comme des protéines potentiellement impliquées dans l’acquisition des résistances aux thérapies ciblées.Ce travail de thèse propose ainsi de nouvelles perspectives quant à la détermination des mécanismes de résistance spécifiques aux thérapies ciblées et à l’identification de nouvelles cibles thérapeutiques chez les patients présentent des mutations activatrices. / Lung cancer is the leading cause of cancer-related death in France and in the world. It is a cancer of poor prognosis, diagnosed at the late stage III or IV, with a 5-years survival of 6% and 1%, respectively. This cancer encompass several histological types, and among them adenocarcinoma account for 40% of the diagnosis. Genetic sequencing of stage IV tumors highlights redundant mutations, and generally exclusives from each other’s, of KRAS, EGFR, BRAF and ALK genes. The identification of these mutations enable, within companion test, to make eligible patients for targeted therapies when molecules are available.Even though these targeted therapies represent a true revolution in patient’s care, the majority of them cannot benefit from these treatments because their tumors do not harbor activating mutations that are targetable (e.g. absence of EGFR, BRAF and ALK mutation, presence of KRAS mutation). Additionally, when they can be treated using an oral molecule, the benefit observed is unfortunately poor in terms of period of time, and all the patients will escape from the treatment. This is for example the case with EGFR mutations.To better understand the molecular mechanisms associated with the resistance events observed in the clinic, and to propose new therapeutics for patient not-eligible for targeted therapies, I studied at the proteome level, the impact these mutations on protein networks, using the BioID technology (proximity-dependent biotinylation identification). More particularly, I have been interested in the activating mutation of EGFR, KRAS, BRAF and ALK. Considering that proteins from the RAS family (HRAS, NRAS and KRAS) are mutated in around 30% of cancers, I have been also interested in the protein network of these proteins to highlight interaction specific to the KRAS isoform.During my thesis, I showed that the protein networks characterized using BioID are much more dense compared to those identified with the more conventional technic of AP-MS (Affinity-purification and mass spectrometry), and that they enable to identify interactors specifically deregulated upon activating mutation. Additionally, the HEK293 cell model (Human Embryonic Kidney) and BEAS2B cell model (non-cancerous lung cell line) showed a high overlapping degree of the interactors identified, suggesting that the strategy used is relevant to identify interactors specific to mutations. This thesis enabled to identify several interactors specific to the mutant KRAS, EGFR, BRAF, NRAS and EML4-ALk fusion. Thirteen interactors specific to the mutated-KRAS have been functionally validated in lung-cancer cell lines models. Finally, using BioID data I have been able to propose a model of EGFR resistance to targeted therapies. This model shows that CBL and IGH2R might be the EGFR partners responsible for therapeutic escape.Altogether, this thesis propose new perspective to determine resistance mechanisms and to identify new therapeutic targets for KRAS-mutated patients.
517

Significations physiopathologiques des hémorphines de type 7 dans le diabète et les cancers broncho-pulmonaires / Physiopathological significations of hemorphin-7 in diabetes and lung cancers

Féron, Delphine 30 April 2010 (has links)
Les hémorphines représentent une classe de peptides cryptiques bioactifs issus de la protéolyse de la chaîne ß de l’hémoglobine dont la présence in vivo a souvent été associée à des conditions physiologiques ou pathologiques particulières, comme les cancers. De ce fait, l’hypothèse d’utiliser ces peptides comme marqueur de pathologies avaient déjà été posé. Des études récentes au laboratoire ont montré que leur concentration sérique des hémorphines était diminuée chez les patients diabétiques. Nous avons travaillé sur une cohorte de 120 patients atteints de diabète de type 1 et 2 et nous avons étudié les différentes hypothèses permettant d’expliquer cette diminution : métabolisme des hémorphines, impact de la glycation de l’hémoglobine sur la libération des peptides. De plus, nous avons cherché à connaître le rôle de LVVH7 dans la signalisation insulinique. Les résultats obtenus suggèrent que la diminution de la concentration sérique des hémorphines de type 7 est spécifique du diabète mais que la glycation de l’hémoglobine n’a pas d’impact sur la libération des hémorphines. Parallèlement à cette étude, nous avons caractérisé les hémorphines de type 7 dans le microenvironnement du cancer broncho-pulmonaire. La cathepsine D, enzyme impliquée dans la libération de LVVH7 et VVH7 ainsi que dans le microenvironnement tumoral, a été étudié dans des cultures de lignées de cancers broncho-pulmonaires acidifiée et donc propice à la progression tumorale. Les résultats ont permis de confirmer la présence de la cathepsine D dans le surnageant de cultures des cellules cancéreuses. De plus, nous avons montré la libération d’hémorphines de type 7 dans des milieux de culture acidifiés. / Hemorphins are cryptic bioactive peptides derived from ß chain of haemoglobin proteolysis. Their biological presence has often been associated with physiological or pathological conditions, like cancers. Thus, it was already suggested that hemorphins could be used as marker of pathology. Previous studies achieved in our laboratory demonstrated that hemorphin-7 was decreased in serum of diabetic patients. We worked on a population of 120 patients with type 1 and type 2 diabetes and we studied different hypothesis: hemorphins metabolism, impact of glycated haemoglobin. Moreover, we researched the role of LVVH7 in insulin signalisation. The results suggested that hemorphin-7 concentrations in serum of diabetic patients are specific of this pathology but glycation of haemoglobin have no impact on liberation of hemorphins. In parallel, we characterized hemorphin-7 in tumor progression of lung cancers. Cathepsin D, previously demonstrated as a key enzyme in hemorphins generation and also in tumor progression, has been studied in vitro in lung cancers, cultured in acidified conditions, favourable to metastasis. In addition, we also identified hemorphin-7 liberation in acidified media culture.
518

Prévention, diagnostic précoce et traitement du cancer broncho-pulmonaire chez les personnes vivant avec le VIH : apport de la tomodensitométrie thoracique sans injection de produit de contraste / Prevention, early diagnosis and treatement of lung cancer in people living with HIV : contribution of chest computed tomography without contrast injection

Makinson, Alain 27 November 2015 (has links)
Cette thèse présente nos travaux sur la prévention, le dépistage, le diagnostic précoce, et traitement du cancer broncho-pulmonaire (CBP) chez les personnes vivant avec le VIH (PVVIH). La finalité de cette synthèse est d’améliorer la prise en charge des PVVIH atteint de ce cancer, mais aussi de développer des axes de recherche après une évaluation rigoureuse de la bibliographie. Nos recherches soulignent tout d’abord que la prise en charge thérapeutique des PVVIH atteintes d’un CBP doit être identique à celle de la population générale, l’infection par le VIH ne constituant finalement qu’une comorbidité supplémentaire. Toutefois, une spécificité de la prise en charge de ce cancer chez les PVVIH est la survenue de complications potentiellement létales secondaires aux interactions et effets toxiques additifs entre les antirétroviraux et les médicaments cytotoxiques. Ce danger nécessite une bonne coordination des équipes oncologiques et infectiologiques, probablement par le biais de réunions de concertation pluridisciplinaires spécifiques, ainsi qu’une bonne connaissance des pharmacocinétiques et pharmacodynamies des produits administrés.Notre étude ANRS EP48 HIV CHEST, qui était une étude transversale multicentrique, a inclus 442 PVVIH à risque de développer un CBP, en raison (principalement) d’un tabagisme > 20 paquets-années, un âge > 40 ans, ainsi qu’un nadir en lymphocytes TCD4 < 350 cellules/ µl. Cette étude a rempli son objectif principal, qui était de démontrer la faisabilité du dépistage du CBP chez les PVVIH en France par TDM thoracique. Le diagnostic d’un nombre important de CBP de stades localisés, et donc guérissables, apporte probablement un bénéfice essentiel aux patients inclus. Le fait qu’aucune complication grave n’ait été engendrée par les explorations diagnostiques, et que la prévalence de nodules significatifs soit dans l’intervalle des résultats d’études en population générale, sont des éléments rassurants. Nos travaux, ainsi que d’autres données de la littérature de prévalence de ce cancer en fonction des âges, font apparaître que l’âge limite de dépistage par TDM faible dose pourrait être de 45 ans chez les PVVIH. Comme en population générale, l’apport du TDM thoracique ne se limite pas au diagnostic de CBP. Il permet d’augmenter l’efficacité du diagnostic précoce de comorbidités ayant un impact sur la qualité de vie et/ou la survie par : 1) le diagnostic des tassements vertébraux, pour la majorité asymptomatique, en rapport avec une prévalence élevée de l’ostéoporose fracturaire dans cette population, 2) l’évaluation de l’emphysème et de la bronchiolite du fumeur, 3) une estimation des calcifications coronaires, qui est associée aux événements cardio-vasculaires. Ce travail a également pour intérêt d’illustrer l’épidémiologie des complications actuelles des PVVIH sous traitement antirétroviral efficace et exposées à une intoxication tabagique. La BPCO, l’emphysème, le CBP, l’athérosclérose coronaire ont une prévalence élevée dans cette population et sont des enjeux importants de santé. Cette épidémiologie rapproche la population des PVVIH de la population générale mais avec des particularités liées, aux antécédents de déficit immunitaire et de traitements antirétroviraux toxiques, et à la prévalence plus élevée des comportements à risque. Pour certaines complications cependant (emphysème, bronchiolite, score calcique), l’absence d’association avec les variables immuno-virologiques souligne la primauté des facteurs comportementaux dans la survenue de ces complications. Ainsi, l’ensemble de ces travaux qui s’articulent principalement autour de l’étude ANRS EP48 HIV CHEST souligne que la réduction des risques liée aux facteurs d’exposition (tabagisme surtout, et probablement cannabis) est une priorité chez les PVVIH à l’ère des combinaisons antirétrovirales. / This thesis is an analysis of our on-going or published works on the theme of prevention, early diagnosis, screening, and treatment of subjects living with HIV with lung cancer. The ultimate objective of this work is to improve care and prevention of lung cancer in people living with HIV (PLWHIV), and to promote research in lung cancer in this population. Our work underscores that lung cancer treatment in PLWHIV should be identical to treatments administered for lung cancer in the general population. HIV is an additional comorbidity to be taken into account, but never a contraindication for optimal therapy. However, there exist specificities in management of PLWHIV with lung cancer, including the propensity for drug-to-drug interactions and additive toxicity between cytotoxic compounds for chemotherapy and antiretroviral therapy, with potentially lethal effects. Managing these toxicities implies optimal cooperation between oncologists and specialists in HIV, as well as good knowledge of pharmacokinetics and pharmacodynamics of these different compounds.The ANRS EP48 HIV CHEST Study in a cross-sectional, multicentre study, which included 442 subjects at lung cancer risk, primarily due to their age (> 40 years), smoking hazard (> 20 pack-years), as well as a CD4 cell nadir count < 350 cells/µl. This study showed feasibility of lung cancer screening with chest Computed Tomography (CT) in PLWHIV. The early diagnosis of localized lung cancers, potentially curable, suggests clinical benefits for most participants with cancer. Also, the facts that no serious adverse events occurred with invasive diagnostic procedures and that the prevalence of positive nodules was in the range of those found in lung cancer screening studies in the general population are reassuring. Also, our work, combined with data from previous epidemiological studies, support a lower age limit for screening lung cancer with chest CT in PLWHIV at risk than in the general population, starting as early as 45 years. As in the general population, the impact of lung cancer screening with chest CT is not limited to the diagnosis of early stage lung cancers. The diagnosis of other morbidities, such as vertebral fractures, generally asymptomatic, emphysema, bronchiolitis, and coronary calcifications, have a probable positive impact on quality of life and a benefit in survival if managed adequately. Our works also illustrate the epidemiology of complications in PLWHIV under antiretroviral therapy and exposed to smoking hazards. Chronic obstructive pulmonary diseases, emphysema, lung cancer, coronary atherosclerosis have high prevalence in this subpopulation of PLWHIV. The epidemiology of these emerging morbidities is close to the epidemiology in the smoking general population, but specificities exist, due to the presence of chronic immunodeficiency, antiretroviral toxicities, and an increased prevalence of behavioural risks in PLWHIV in comparison with the general population. However, some complications are not associated with HIV-related and immunological factors, such as prevalence of emphysema, coronary calcifications, and bronchiolitis, underscoring the major impact of behavioural hazards in the occurrence of these complications.Taken together, our work highlights the importance of reducing health hazards in PLWHIV, primarily smoking and probably cannabis, to reduce the emergence of these new life-threatening morbidities in the era of highly active antiretroviral therapy.
519

Mécanismes intracellulaires de la transformation médiée par l’enveloppe de JSRV / Intracellular pathways involved in JSRV envelope mediated transformation

Monot, Margaux 16 December 2015 (has links)
Les cancers sont un groupe de maladies diverses et complexes responsables de millions de décès chaque année à travers le monde. Ces maladies sont multicausales et peuvent être engendrées par de nombreux facteurs génétiques ou environnementaux. Parmi les facteurs susceptibles de déclencher l’oncogénèse, les agents infectieux (virus, bactéries et parasites) sont à l’origine de plus de 16 % des cancers. Parmi les virus, l’étude de la famille des Retroviridae a permis de comprendre les mécanismes de l’oncogénèse virale. Certains rétrovirus portent des oncogènes d’origine cellulaire, d’autres activent des oncogènes cellulaires lors de leur insertion dans le génome de l’hôte et d’autres enfin portent des protéines virales oncogènes. Parmi ces derniers, le rétrovirus JSRV (Jaagsiekte Sheep Retrovirus) est responsable de l’adénocarcinome pulmonaire ovin chez les petits ruminants. JSRV transforme des cellules épithéliales alvéolaires et bronchiolaires via sa protéine d’enveloppe (Env) qui dérégule des voies de signalisation cellulaire contrôlant la prolifération, dont la voie Akt/mTOR (Phosphatidylinositol 3-kinase Alpha serine-Threonine-protein Kinase/ mammalian Target Of Rapamycin). Nous avons identifié la protéine cellulaire RALBP1 (RalA Binding Protein 1) comme un partenaire de Env et analysé les effets de cette interaction sur la transformation induite par JSRV. Nous avons confirmé la formation de complexes protéiques RALBP1/ Env dans les cellules de mammifères. Par inhibition de l'expression de RALBP1 avec des siRNA spécifiques, nous avons montré que la protéine cellulaire est impliquée dans le processus de transformation cellulaire induite par l’enveloppe et dans la modulation de la voie mTOR /p70S6K. Nous avons mis en évidence la sous-expression de RALBP1 dans les cellules exprimant Env in vitro, mais aussi ex vivo dans les cellules primaires tumorales et in vivo dans les tissus tumoraux. Nous avons déterminé que CDC42, un activateur de p70S6K dont l’activité est négativement régulée par RALBP1, interagit avec l’enveloppe de JSRV. Nous avons posé l’hypothèse que la diminution de RALBP1 provoquée par l’Env activerait CDC42 ce qui conduirait à l’activation p70S6K. CDC42 étant impliqué dans l’organisation du cytosquelette d’actine, nous nous sommes intéressés à l’effet de l’enveloppe sur le cytosquelette d’actine. Nous avons mis en évidence une désorganisation du cytosquelette d’actine et une perte de la polarisation des cellules exprimant l’enveloppe de JSRV. Comme de nombreux autres virus, JSRV pourrait moduler le cytosquelette d’actine des cellules épithéliales qu’il infecte afin de désorganiser l’épithélium et ainsi affecter son hôte plus efficacement / Worldwide, cancers are a group of diverse and complex diseases responsible for millions of deaths every year. These diseases are multicausal and associated with various genetic and environmental factors. Infectious agents (viruses, bacteria and parasites) are at the origin of more than 16 % of cancers. Among viruses, the study of the Retroviridae family allowed us to understand the mechanisms of viral oncogenesis. They transform cells by carrying oncogenes, by the activation of cellular oncogenes after their integration into the host genomes or by the oncogenic properties of some of their proteins. Among the later, JSRV (Jaagsiekte Sheep Retrovirus) is responsible for ovine lung adenocarcinoma in small ruminants. It transforms alveolar and bronchiolar epithelial cells via its envelope protein (Env). Env expression deregulates pathways involved in the control of cellular proliferation, such as the Akt/mTOR (Phosphatidylinositol 3-kinase Alpha serine-Threonine-protein Kinase/ mammalian Target Of Rapamycin) pathway. We identified RALBP1 (RalA Binding Protein 1) as a cellular partner of Env and analyzed the effects of these interaction on the JSRV induced transformation. We confirmed the formation of RALBP1/Env complexes in cells. By inhibition of RALBP1 expression with specific siRNA, we showed that RALBP1 is involved in Env mediated transformation and in the modulation of the mTOR/p70S6K pathway. We demonstrated the down expression of RALBP1 in vitro in cell lines expressing Env, and importantly ex vivo in primary cells derived from tumoral lungs and in vivo in tumoral lungs. We determined that CDC42, an activator of p70S6K whose activity is negatively regulated by RALBP1, interacts with the envelope of JSRV. We make the hypothesis that the activation of CDC42, following the Env-mediated decrease of RALBP1, would lead to the activation of p70S6K. As CDC42 is involved in the organization of the actin cytoskeleton, we were interested in the effect of Env on actin cytoskeleton. We showed the disorganization of actin cytoskeleton and the loss of polarization in cells expressing Env JSRV. As many viruses, JSRV could modulate the actin cytoskeleton in epithelial cells via its envelope in order to disrupt the epithelium and affect its host more efficiently
520

Disease Representations in Late Modernity: Lung Cancer Stories in the Canadian Print Media

Berger, Jessica January 2012 (has links)
The following thesis describes and analyses the representation of lung cancer in the Canadian print media. The thesis employs a theoretical framework comprised of Giddens’ theory of reflexivity and Goffman’s theory of framing, to understand the social dynamics of negotiation behind the disease’s portrayal in the media, in a late modern context. Late modernity was defined by institutional reflexivity and a focus on understanding and mitigating risk. The research was conducted through a content analysis and examined quantitative trends that contributed to a subsequent qualitative interpretation. The results show that the coverage of lung cancer decreased over time. The analysis shows a discourse of a biomedical institution that has unsuccessfully controlled the disease, a lack of patient advocacy, particularly among celebrities, and a continued conflation of smoking behaviour and lung cancer, all of which contributed to the decreasing coverage. The framing processes point to a society focused on understanding risk through studying the disease’s causes, as well as one concerned with legislative debate and behavioural prevention. The emergence of a frame focused on the patient’s lived experience might contribute to an improved representation of the disease.

Page generated in 0.0465 seconds