A inexistência de um agente terapêutico único satisfatório para o tratamento do melanoma metastático e a potencialidade do quimioterápico 5FU (5-fluorouracil) motivou esta pesquisa, a qual teve por objetivo o desenvolvimento tecnológico de sistemas carreadores micro-/ e nanoestruturados contendo 5FU a fim de aumentar sua eficácia terapêutica e reduzir a toxicidade por meio da administração pulmonar. Duas formulações pulverulentas foram desenvolvidas com polímeros naturais, sulfato de condroitina e hidroxipropil-metil-celulose, denominadas 5FU-MS e 5FU-NS, utilizando as técnicas de aspersão e atomização vibracional piezoelétrica, respectivamente. Ambas as formulações foram avaliadas quanto às características físicas e químicas, perfil toxicológico in vivo (C. elegans e em ratos Wistar), e penetração e biodisponibilidade no tecido pulmonar pela quantificação da fração livre de fármaco por microdiálise pulmonar. A análise físico-química revelou a obtenção de partículas micrométricas para 5FU-MS e submicrométricas para 5FU-NS, com diâmetros médios de partícula de 2,546 ± 0,07 m e 0,652 ± 0,03 m, e fração respirável (FR%) de 55,12 ± 2,98 e 76,84 ± 0,07, respectivamente. Ambas demonstraram características e propriedades adequadas para administração pulmonar, com capacidade de deposição nas porções média e profunda. A toxicidade das formulações avaliada em C. elegans considerou o percentual de morte, desenvolvimento, DL50 e produção de ROS para os nematodos sob tratamento agudo e crônico. Os resultados evidenciaram redução significativa da toxicidade proporcionada pela redução da taxa de morte e maior desenvolvimento dos grupos tratados com as formulações 5FU-MS e 5FU-NS em comparação ao fármaco livre, sugerindo perfis de segurança satisfatórios para administração. Além disso, 5FU-MS revelou-se um agente pró-oxidante, representando um diferencial promissor deste sistema, podendo alcançar maior sensibilização das células tumorais com menores doses. A toxicidade pulmonar aguda foi avaliada pela análise de LDH e proteínas totais no fluido de lavagem bronco-alveolar (BALF) após a administração combinada das formulações 5FU-MS e 5FU-NS para administração como um sistema terapêutico único (5FU-MS/NS), e análise de dano tecidual pulmonar em ratos. Os resultados da análise bioquímica e histológica indicaram o baixo potencial de indução de lesão tecidual a partir da administração pulmonar combinada das formulações, em relação ao fármaco livre. A análise do perfil farmacocinético por microdiálise pulmonar evidenciou o êxito no desenvolvimento dos sistemas carreadores, tornando possível duplicar o t1/2 do 5FU e aumentar significativamente a biodisponibilidade no tecido pulmonar. Os resultados obtidos indicam a eficiência das formulações 5FU-MS e 5FU-NS em alcançar os benefícios terapêuticos do fármaco 5FU com menores doses e maiores intervalos de administração. Este trabalho de tese apresenta uma abordagem promissora na terapia de neoplasias com recorrência de metástase pulmonar. / The absence of a single therapeutic agent suitable for the treatment of metastatic melanoma and the potential of 5FU chemotherapy (5-fluorouracil) motivated this study, which aimed the development of carrier systems based on micro-/ and nanostructures containing 5FU to increase the therapeutic efficacy and reduce toxicity of this drug by pulmonary administration. Two different formulations of dry powders were developed with natural polymers, chondroitin sulfate and hydroxypropyl-methyl-cellulose, denomined 5FU-MS and 5FU-NS, using the spray-drying and vibrational piezoelectric atomization techniques, respectively. Both formulations were evaluated in terms of physico-chemical characteristics, in vivo toxicological behaviors (C. elegans and in Wistar rats), bioavailability and penetration in the lung tissue by quantifying of drug free fraction by lung microdialysis. The physicochemical analysis showed that were obtained as micrometric (5FU-MS) and submicron particles (5FU-NS), with average diameters of particle 2.546 ± 0.07 m and 0.652 ± 0.03 m, and respirable fraction (FR%) of 55.12 ± 2.98 and 76.84 ± 0.07, respectively. Both showed suitable characteristics and properties for pulmonary delivery, with deposition capacity in the middle and deep lung portions. The toxicity of the formulations evaluated in C. elegans considered the death rate, body development, DL50 and production of ROS to nematodes under acute and chronic treatment. The results showed significant reduction of toxicity, reducing the death rate and greater development of the groups treated with 5FU-MS and 5FU-NS formulations compared to the free drug, suggesting satisfactory safety profile for administration. In addition, 5FU-MS proved to be a pro-oxidant agent, representing a promising differential of this system which can achieve greater sensitization of tumoral cells with lower doses. Acute pulmonary toxicity was evaluated by analyzing LDH, and total protein in the bronchoalveolar lavage fluid (BALF) after combined administration of 5FU-MS formulations and 5FU-NS for administration as a single therapeutic system (5FU-MS/NS) and analysis of lung tissue damage in rats. The results of biochemical and histological analysis indicated the low potential to induce tissue damage from the pulmonary administration of combined formulations, compared to free drug. Analysis of the pharmacokinetic profile for pulmonary microdialysis showed the successful development of carrier systems, making it possible to double the t1/2 of 5FU and significantly increase bioavailability in lung tissue. The results indicate the effectiveness of the formulations 5FU-MS and 5FU-NS in achieving the therapeutic benefits of the drug 5FU at lower doses and higher dosing intervals. This thesis work presents a promising approach to cancer therapy with lung metastasis recurrence.

>Magister Scientiae - MSc / Tyrosinase is an enzyme widely distributed in the biosphere and is found in many species of bacteria, fungi, animals, and plants; it is associated with melanin production. Even though it possesses many beneficial properties such as photoprotection, but overproduction causes undesirable effects such melasma, solar lentigines etc. Therefore, tyrosinase enzyme inhibitors are of far-ranging importance in cosmetics, medicinal products, and food industries. This study is aimed to test anti-tyrosinase activity in 37 plants from 20 families using mushroom tyrosinase inhibition method; each plant was extracted with methanol. The results showed that 17 plant extracts, exerted a considerable level of in vitro tyrosinase inhibition comparable to positive controls of kojic acid in the same solvent systems when evaluated spectrophotometrically. Among plant extracts, those that showed an inhibition rate >50 % at 50 μg/ml and ˃60 % at 200 μg/ml were A. karroo (Hayne.), A. afra Jacq. Ex Willd, C. geifolia (L.), E. racemosa (L.), H. petiolare Hilliard & B.L.Burt, M. quercifolia (L.), M. communis (L.), P. rigida (Wikstr.), P. ecklonii (Benth.), P. ericoides (L.), S. Africanacaerulea (L.), S. Africana-lutea (L.), S. antarcticus (Willd.), S. lucida (L.) F.A.Barkley, S. hamilifolius (L.), S. furcellata R.Br and T riparia which exhibited great anti-tyrosinase activity.

Le mélanome est un cancer de la peau agressif et au mauvais pronostic. Si de nouvelles solutions thérapeutiques efficaces ont été développées, les taux de réponses sont variables et transitoires. Découvrir de nouveaux mécanismes oncogéniques dans cette pathologie reste donc nécessaire. Durant mes travaux, j’ai pu démontrer que la protéine tyrosine-kinase FES est exprimée dans les mélanocytes normaux. Cette expression est largement perdue dans un panel de lignées cellulaires de mélanome, au niveau protéique et transcriptionnel ainsi que dans des cultures primaires d’échantillons de patients. La perte de FES est due à une hyper-méthylation de son promoteur et est réversible. En ré-exprimant FES de manière stable dans deux lignées cellulaires de mélanomes, j’ai montré que cette réexpression entraînait une diminution des capacités oncogéniques des cellules. De plus, en analysant les données d’une cohorte de mélanomes (TCGA), j’ai pu établir qu’une diminution importante ou une perte d’expression de FES se retrouve dans près de 40% des patients, et qu’elle est corrélée à une hyper-méthylation du gène FES. Les patients ayant une faible expression de FES présentent un moins bon pronostic soulignant l’importance de ce phénomène. Enfin, en croisant un modèle murin déficient pour le gène Fes avec un modèle de mélanome, nous observons que les tumeurs sous fond Fes KO sont plus prolifératives et plus volumineuses.Ainsi, par des analyses in vitro, sur des données de patients ou en croisant des modèles murins, j’ai pu démontrer que FES est exprimée au niveau des mélanocytes normaux et y exerce un rôle de suppresseur de tumeur. / Among skin cancers, melanoma is the most aggressive and has the worst prognosis. In the last years, new therapeutic tools have been developed but responses differ between patients and are often transient due to resistance mechanisms. This highlights the need to improve understanding of molecular mechanisms of the disease. During my thesis, I have shown for the first time that FES tyrosine kinase is expressed in normal melanocytes, and that its expression is lost at the protein and RNA levels in most melanoma cell lines. The same result is observed in a panel of 12 patients’ short-term cultures. The lack of expression is due to FES promoter hyper-methylation and can be reverted using a hypomethylating agent. By restoring FES expression in two melanoma cell lines, I observe a decrease of oncogenic properties of the cells. Moreover, the analysis of the TCGA data on melanoma indicate that FES expression is strongly decreased or lost in about 40% of patients, and that this loss of expression is correlated with FES promoter methylation. Importantly, patients with low level of FES mRNA have poor prognosis compared to FES expressing patients. Finally, Fes knock-out mice crossed with an inducible melanoma mouse model indicate that tumors proliferation and size are more important under a Fes KO background.In conclusion, by using melanoma cells in vitro, data from melanoma patients and mouse models, I have demonstrated that FES is expressed in normal melanocytes and clearly plays a tumor suppressor role.in melanoma.

Nas últimas décadas, é intensa a procura de uma explicação genética sobre a origem, crescimento e progressão do melanoma cutâneo. A tentativa de encontrar uma ligação direta entre as mutações gênicas e a origem da doença tem sido o objetivo dos pesquisadores dedicados ao estudo dessa neoplasia. Diversos métodos são utilizados na busca de uma avaliação prognóstica para a progressão do melanoma, citando-se, entre eles, a pesquisa do linfonodo sentinela, a imunoistoquímica, as técnicas moleculares e a técnica de microarray. A necessidade de estabelecer um método, com excelente sensibilidade e especificidade, tem levado os pesquisadores a buscarem melhores evidências. É importante para esses estudos a obtenção de dados confiáveis sobre as técnicas, progressão e sobrevida livre de doença. Por meio da imunoistoquímica, técnica relativamente simples e de baixo custo, a expressão da proteína p16 pode ser analisada e correlacionada com o prognóstico da doença. No melanoma cutâneo, a expressão da proteína diminui, à medida que aumenta sua agressividade, ou seja, é forte nos nevos e melanomas in situ, e fraca ou ausente nos melanomas metastáticos. Em alguns estudos, a comparação com outros marcadores é analisada. A finalidade deste estudo é fazer uma revisão da literatura internacional sobre o uso da proteína p16 como fator prognóstico para o melanoma, bem como avaliar a importância das alterações do gene p16INK4a, co-responsáveis pela gênese e evolução do melanoma.

Melanoma é um tipo maligno de lesão de pele pigmentada, e atualmente está entre os tipos de câncer existentes mais perigosos. Entretanto, diferenciar casos malignos de benignos é uma tarefa difícil mesmo para experientes especialistas, e um sistema de diagnóstico auxiliado por computador pode ser uma ferramenta bastante útil. Normalmente, este sistema inicia por um pré-processamento da imagem, isto é, remoção de artefatos indesejados, como pelos, sardas ou efeitos de sombreamento. A seguir, o sistema executa uma etapa de segmentação, identificando as bordas da lesão. Por fim, baseando-se na área da imagem identificada como lesão, diversas feições são computadas e uma classificação é gerada. Neste tese, apresentada na forma de uma coleção de artigos publicados, nós apresentamos técnicas para automaticamente executar todos estes passos, resultando em um pré-diagnóstico para uma lesão de pele pigmentada baseado apenas em uma imagem convencional (uma simples fotografia). Nós testamos nossos métodos em bases de imagens públicas e atingimos melhores resultados de segmentação e classificação que os demais métodos presentes na literatura. / Melanoma is a type of malignant pigmented skin lesion, and currently is among the most dangerous existing cancers. However, differentiating malignant and benign cases is a hard task even for experienced specialists, and a computer-aided diagnosis system can be an useful tool. Usually, the system starts by pre-processing the image, i.e. removing undesired artifacts such as hair, freckles or shading effects. Next, the system performs a segmentation step to identify the lesion boundaries. Finally, based on the image area identified as lesion, several features are computed and a classification is provided. In this Thesis, presented as a collection of published papers, we detail approaches to automatically execute all these steps, resulting in a pre-diagnosis for a pigmented skin lesion based only in a standard camera image (i.e. a simple color photograph). We tested our methods on publicly available datasets and achieved better segmentation and classification results than methods previously proposed in the literature.

Adolescents and Young Adults (AYAs) ages 15-39 years with cancer have received little attention in the medical and health fields, resulting in a lack of progress for this age group. Little is known about the unique biologic, epidemiologic, and psychosocial issues that play an integral role in the AYA cancer journey. The purposes of this study were to use the Tennessee Cancer Registry for all new cancer cases from 2004-2008 to determine 1) the main types of cancer that affect AYAs in TN, 2) the predictors of late-stage diagnosis of melanoma, and 3) the factors that predict a total thyroidectomy for cancer treatment. A total of 8,097 cancer cases were diagnosed in AYAs in Tennessee from 2004-2008. The five main cancer types were breast cancers, melanomas, thyroid cancers, lymphomas, and testicular cancers and accounted for over 50% (N=4,269) of cancers in AYAs in Tennessee during the study period. Females were significantly more likely to be diagnosed with melanomas (age adjusted incidence rate (AIR) 14.01, 95% CI 12.96-15.06) and thyroid cancers (AIR 13.39, CI 12.37-14.42) compared to males (AIR 8.08, CI 7.28-8.88 and AIR 3.50, CI 2.98-4.03, respectively). All cancer types increased with age. Individuals with government insurance (OR 8.41, CI 3.04-23.27) and those 15-19 years of age (OR 6.30, CI 1.74-22.86) had the highest risk of late-stage melanoma. Significant predictors of a using total thyroidectomy for thyroid cancer treatment included regional/distant stage cancer at diagnosis (OR 2.80, CI 1.34-5.85) compared to localized stage, papillary carcinoma (OR 2.64, CI 1.02-6.83) and papillary adenocarcinoma (OR 3.56, CI1.37-9.19) histology types compared to follicular adenocarcinoma, and residence in non-Appalachian Tennessee (OR 2.07, CI 1.26-3.42) compared to Appalachian TN. An increased awareness of cancer types that affect AYAs in Tennessee will provide a basis for developing public health campaigns for cancer prevention and control in this population. This research serves as a first step in using state-based cancer registries to identify the unique characteristics of cancer in AYAs and will set the stage for future state-based research in this underserved population.

Skin cancer is a major public health concern, and tanning remains a modifiable risk factor. Multidimensional influences, including psychosocial, individual, environmental, and policy-related factors, create the milieu for individuals to engage in tanning. Parents and physicians can modify the behavior of teens and young adults using strategies based on harm reduction. Environmental and policy-related factors similar to those used to limit smoking by restricting access of minors to cigarettes in the United States in the 20th century need to be created. Federal regulations can restrict direct advertising and the excise tax can be increased to a prohibitive amount. Social networking may assist with affect regulation.

La progression tumorale dépend d'un dialogue entre les cellules cancéreuses et leur environnement. Parmi les cellules du microenvironnement du mélanome, les adipocytes ont longtemps été ignorés. Pourtant, ces cellules sont le composant majeur de l'hypoderme, la couche la plus profonde de la peau. Ainsi, elles sont proches du mélanome lors de la tumorigenèse et, lorsque la tumeur envahi les couches profondes de la peau, les deux types cellulaires entrent en contact. Il est donc important de comprendre l'impact des adipocytes sur la progression du mélanome, d'autant plus que des études épidémiologiques montrent que l'obésité est un facteur de mauvais pronostic pour ce cancer. Le surpoids et l'obésité sont en hausse constante avec près d'un tiers de la population mondiale affectée, faisant du lien entre l'obésité et le cancer un enjeu de santé publique majeur. Parmi les différents moyens de communication cellulaire, les vésicules extracellulaires (VE) jouent un rôle important dans le cancer. Les VE régulent la communication entre les cellules cancéreuses mais aussi entre les composants du microenvironnement et la tumeur. Les VE sécrétées par les adipocytes sont peu caractérisées et leur rôle sur la progression tumorale reste à élucider. Les VE adipocytaires pourraient être modifiées qualitativement et quantitativement en obésité car différents stress (inflammation, hypoxie...), connus pour modifier les VE, sont retrouvées dans le tissu adipeux d'individus obèses. Dans ce contexte, le premier objectif de ma thèse était de caractériser les VE adipocytaires et déterminer leur impact sur le mélanome dans un contexte normopondéral et d'obésité. Les résultats obtenus montrent que ces VE favorisent la migration et l'invasion des cellules de mélanome. Une analyse protéomique a révélé une signature spécifique dans ces VE, fortement enrichies en protéines du métabolisme des acides gras (AG).[...] / It is now clear that tumor progression is the result of a permanent dialog between cancer cells and the tumor microenvironment (TME). Among the cells found within the melanoma microenvironment, adipocytes had long been ignored. However, adipocytes are the main component of the hypodermis, the deepest skin layer, and are therefore close to melanoma from tumorigenesis and, as the tumor becomes aggressive and invades the deeper skin layers, the two cell types come into contact. Thus, understanding how adipocytes influence melanoma progression is of major importance, especially since epidemiological studies show that obesity is a poor prognosis factor for melanoma. As overweight and obesity are constantly rising and affect around a third of the World's population, the link between obesity and cancer is a major public health issue. Among the different ways in which cells communicate, extracellular vesicles (EV) play a particularly important role in cancer. Moreover, not only can tumor cells communicate with each other through EV, but the cellular components of the TME also use EV to communicate with cancer cells. Adipocyte-derived EV are poorly characterized and their role in tumor progression remains to be determined. In obesity, adipocyte EV may be qualitatively and quantitatively altered since various stresses (inflammation, hypoxia etc.), which are known to modify EV, are found in the adipose tissue of obese individuals. In this context, the first aim of my thesis was to characterize adipocyte EV and their impact on melanoma in lean and obese individuals. The results obtained show that EV secreted by adipocytes promote migration and invasion of melanoma cells. Analysis of their proteome revealed a protein signature specific to adipocyte EV, which was highly associated with fatty acid (FA) metabolism, a metabolic pathway involved in tumor aggressiveness. In melanoma treated with adipocyte EV, fatty acid oxidation (FAO) is increased and FAO inhibitors reverse their pro-invasive effect. Moreover, adipocytes secrete increased numbers of EV in obesity and, using equal numbers of EV from lean or obese subjects, their effect on tumor aggressiveness is increased and remains dependent on FAO. T[...]

Le mélanome cutané est le plus agressif des cancers de la peau. Une fois métastasé, les options thérapeutiques sont limitées et peu efficaces. Dans le but de trouver de nouveaux marqueurs d'agressivité du mélanome cutané, une étude protéomique comparative entre deux lignées de mélanome murin, génétiquement semblables mais avec des agressivités différentes, a permis d'identifier l'annexine A1 (ANXA1) comme une protéine pro-invasive. Le but de ce travail de thèse a été d'évaluer la valeur pronostique d'ANXA1 et de déterminer son rôle et son mode d'action dans les processus d'invasion des mélanomes humains. Lors d'une étude immunohistologique rétrospective sur deux centres (Clermont-Ferrand et Saint-Etienne), il a été observé, indépendamment de l'indice de Breslow, une corrélation inverse entre le taux d'ANXA1 dans les tumeurs primitives de 61 patients et le délai d’apparition des métastases. Cette association est due à l’implication d’ANXA1 dans les processus d’invasion. En effet,nous avons démontré dans différentes lignées de mélanome qu'ANXA1 extracellulaire stimule les récepteurs aux peptides formylés (FPRs) exprimés par ces cellules. Cette fixation aux FPRs induit les voies des MAPK et STAT3 qui entraînent l'activation des métalloprotéases (MMP2). L'induction des MMP2 par ANXA1 augmente significativement le pouvoir invasif des lignées de mélanome. Nous avons aussi démontré qu’ANXA1 est transloquée coté externe de la membrane cytoplasmique là où elle subit un clivage par une sérine protéase qui pourrait être la nicaline. Ce clivage qui se produit après la sérine 28 n'a pas été décrit et jouerait un rôle dans la capacité invasive des mélanomes en libérant un ou des peptide(s) proinvasif(s). A long terme, ce travail vise à utiliser ANXA1 comme marqueur pronostique et/ou cible thérapeutique du mélanome cutané. / Cutaneous melanoma is the most aggressive skin cancer. Treatment options are limited and inefficient when melanoma has metastasized. In order to identify new markers of melanoma dissemination, protein profiles of two genetically similar murine melanoma cell lines have been compared. Both B16F10 and B16Bl6 cells induced primary tumours after subcutaneous graft, however, only B16Bl6 melanomas develop metastases. Among proteins differentially expressed, annexin A1 (ANXA1) is overexpressed in the aggressive B16Bl6 melanoma.The aim of the present work was to assess ANXA1 prognostic value in human melanoma and todecipher its implication in the invasion process. We report that, regardless of Breslow index, ANXA1 expression in primary tumours of 61 patients is inversely correlated with time to metastasis. This correlation is due to ANXA1 involvement in the invasion processes. Indeed, we show that in different human melanoma cell lines, extra cellular ANXA1 stimulates Formylated Peptide Receptors (FPRs). FPRs/ANXA1 interaction induces MMP2 activity through MAP Kinase and STAT3 pathways. ANXA1-stimulated MMP2 induces a significant increase of cell invasion ability. We also show that ANXA1 is externalized and localized on the cell surface where it is cleaved by a serine protease, which could be nicalin. ANXA1 cleavage occurs after Serine 28, a so far not described site. These data suggest that ANXA1 cleavage might be associated with invasion ability of melanoma cells by release of proinvasive peptide(s).These findings identify ANXA1 as a melanoma proinvasive protein that might be a promising prognosis marker and therapeutic target.

Bien qu'il concerne que 10% des cancers de la peau, le mélanome cutané est à l'origine de 80% de la mortalité due à ce type de cancer. L'objectif de mon travail de thèse était de mesurer l'efficacité cytotoxique de nouveaux complexes de platine (les NHC-Pt) dans le mélanome cutané métastatique, mais également de décrire leurs mécanismes d'action. Ces complexes pouvant être radiomarqués, nous avons vérifié l'hypothèse selon laquelle les propriétés chimiotoxiques du platine peuvent être combinées aux propriétés radiotoxiques d'électrons de faible énergie émis par l'iode 123. Enfin, ce radiomarquage a permis une première approche de la biodistribution des composés NHC-Pt. J'ai montré que le composé NHC-Pt-I2, avait un effet cytotoxique important dans des lignées de mélanome métastatiques BRAF mutés et wild-type ainsi que dans des lignées de mélanome rendues résistantes au vemurafenib, un inhibiteur de BRAF. L'obtention de cet effet après une exposition très courte (1h) des cellules, témoigne de la rapidité de déclenchement des processus cytotoxiques cellulaires, contrairement à ce qui a été observé avec le cisplatine et la dacarbazine. Les études de pharmacocinétique ont permis de rapporter l'importance de l'effet cytotoxique obtenu avec un traitement d'1h sur les cellules à une accumulation cellulaire du composé NHC-Pt-I2 importante. Cette accumulation était supérieure (95 fois) à celle du cisplatine, et permettait une induction massive de dommages à l'ADN. Les études mécanistiques ont montré que les composés NHC-Pt induisaient l'apoptose des cellules d'une part via la voie Bcl-xL, et d'autre part via une autre voie dépendante des pan-caspases non identifiée à l'heure actuelle. Le radiomarquage par l'iode-123 du composé NHC-Pt-Br2 a permis d'étudier sa biodistribution in vivo chez la souris. Le composé NHC-Pt-Br-123I présente une distribution rapide et importante vers le compartiment sanguin, une accumulation très faible dans les principaux organes, et une légère accumulation tumorale. En revanche, l'étude de la synergie des effets cytotoxiques du Pt par l'effet des électrons de faible énergie émis par l'I123 a été limitée par le très faible rendement de marquage de composés radiomarqués obtenu. Les résultats obtenus durant ce projet de thèse ont permis de révéler le potentiel important des composés NHC-Pt comme outil thérapeutique du mélanome cutané métastatique / Although only 10% of skin cancers are due to cutaneous melanoma, but it’s still responsible for 80% of the mortality caused by this type of cancer. The aim of my thesis was evaluating the cytotoxicity of new platinum complexes (NHC-Pt) in metastatic cutaneous melanoma and investigating their mechanisms of action. These complexes can be radiolabeled. We studied if chemotoxicity of platinum combined by radiotoxicity of low energy electrons emitted by 123 Iodine (123I) can lead to a higher cytotoxicity. This radiolabelling also permitted us to study the biodistribution of the NHC-Pt compounds. We have shown that the compound NHC-Pt-I2, not only had a significant cytotoxic effect on mutated and wild-type BRAF metastatic melanoma cell lines but also on melanoma cell lines resistant to vemurafenib which is a BRAF inhibitor. Getting results in a very short cell exposure time (1h), showed a rapid onset of cellular cytotoxicity, and it’s contrary to what was observed in cisplatin and dacarbazine. We also showed that cytotoxic effect obtained by 1h treatment of cells was due to higher cellular accumulation of the NHC-Pt-I2. This higher accumulation was about 95 times more than that of cisplatin and allowed much more DNA damage induction. Our Mechanistic studies showed that NHC-Pt compounds induce cell apoptosis via the Bcl-xL pathway and also there is another pathway dependent on pancaspases which is still unidentified. The radiolabelling with 123I of the NHC-Pt-Br2 enabled the in vivo study of its biodistribution in mice. The NHC-Pt-Br-123I compound had a fast and important distribution to the blood compartment, and a very slight accumulation in the main organs, and also in tumors. On the other hand, the study of amplification of Pt cytotoxicity by the effect of 123I was limited by very low labelling efficiency of radiolabelled compounds. The reason of this low efficacy may be the special commercial saline solutions of 123I that we used. The results achieved during this thesis project revealed the important potential of NHC-Pt compounds as a therapeutic tool for metastatic cutaneous melanoma