INTRODUCTION: Pancreatic Ductal Adenocarcinoma (PDAC) is an aggressive form of cancer with a high mortality rate, primarily due to lack of effective treatment options. Current therapeutic approaches are limited to surgical resection of the pancreas during early stages of the disease and to the use of non-specific chemotherapeutic drugs such as gemcitabine, neither of which has successfully improved the 5-year survival rate of PDAC. Both the lack of effective treatments and the high mortality of the disease call for the urgent need to develop new therapeutic options. OBJECTIVES: This thesis project focuses on an endogenous inhibitor of the neuropilin 2 receptor (NRP2) called semaphorin 3F (SEMA3F) and its use as a potential new drug in the fight against pancreatic cancer. By binding the transmembrane receptor neuropilin 2 (NRP2), SEMA3F can inhibit angiogenesis and cellular proliferation. Interestingly, given its role as a guidance molecule, it is also a potent mediator of cellular repulsion. All three of these effects will be analyzed in the context of this study. METHODS: Syngeneic pancreatic cancer cells were injected orthotopically in two separate groups of mice. One group involved the use of transgenic Nrp2-/- mice, and served as a way to analyze the absence of the receptor on the vasculature and how that affects the growth of the primary tumor and the formation of metastases in the liver. The other group received intravenous injections of SEMA3F-expressing and control adenovirus, and served to explore the effect of SEMA3F as a potential therapy against the growth of the primary tumor in the pancreas and distant metastases in the liver. RESULTS: We observed a decrease in pancreatic tumor and metastatic growth in the absence of Nrp2 in our transgenic mouse model compared to the WT control. Mice injected with SEMA3F-expressing adenovirus also showed a decrease in primary tumor growth as well as a reduction in the formation of metastases in the liver compared to the control. CONCLUSION: Nrp2 mediates angiogenesis in pancreatic cancer, which facilitates the growth of the primary tumor as well as the formation of metastases. Our results indicate that the anti-angiogenic, anti-proliferative and repulsive actions of SEMA3F could be used to develop an effective treatment option for PDACpancreatic ductal adenocarcinoma. / 2020-07-24T00:00:00Z

Pode-se afirmar que no século XX originou-se uma indústria farmacêutica multinacional com extraordinária capacidade de pesquisa e desenvolvimento para produzir novos fármacos. Porém, contradizendo este potencial inovador, o número de fármacos introduzidos no mercado vem declinando desde 1960 e as oportunidades abertas com os avanços da biologia molecular, da genômica, da bioinformática e da química ainda não trouxeram os resultados esperados. No Brasil, a pesquisa científica tem obtido resultados de grande relevância, mas encontra muitas dificuldades para levar novos produtos ao mercado. O objetivo principal deste trabalho é discutir estratégias de fomento para a pesquisa e desenvolvimento de fármacos no país, procurando conciliar os requisitos técnicos e econômicos deste processo com as competências preexistentes. O referencial metodológico adotado enfatiza o papel determinante das relações econômicas na pesquisa e desenvolvimento de fármacos e procura encontrar caminhos compatíveis com a realidade nacional. Para tanto, discute as características técnicas e econômicas desta atividade, bem como a estratégia das empresas inovadoras e algumas experiências brasileiras nesta área do conhecimento. Fundamentado na análise de 766 novos fármacos introduzidos no mercado mundial entre 1984-2003, nos pilares econômicos do processo de inovação e no contexto político-institucional da pesquisa e desenvolvimento de fármacos, propõe alternativas para aprimorar o desenvolvimento científico e tecnológico do setor farmacêutico brasileiro. Muitas atividades relacionadas com a pesquisa e desenvolvimento de fármacos são realizadas no país, mas encontram-se dispersas nas principais universidades, centros e institutos de pesquisa. O mapeamento destas competências representa o ponto de partida para a criação de uma rede de inovação no setor farmacêutico. Um dos gargalos identificados neste trabalho é a fragilidade do suporte institucional para negociações de alta tecnologia, do qual fazem parte as patentes, os acordos de cooperação e a transferência de tecnologia. Para viabilizar, no Brasil, a incorporação de ferramentas de alta tecnologia empregadas no desenvolvimento de fármacos foi proposta a criação do Laboratório Nacional de Pesquisa e Desenvolvimento de Fármacos. Além de garantir sofisticação técnica, este Laboratório Nacional atuaria como instituição aberta, multidisciplinar, assumindo o papel de um centro de articulação das iniciativas voltadas para o desenvolvimento de fármacos, podendo gerar recursos para financiar a pesquisa e contribuir para o desenvolvimento científico e tecnológico. Acordos de cooperação com empresas inovadoras e organismos internacionais fazem parte das estratégias para captação de recursos. Linhas de pesquisa alinhadas com as necessidades do Sistema Único de Saúde e com outras políticas do setor público também devem nortear a pesquisa e desenvolvimento de fármacos no país. A exploração de novos alvos moleculares, articulada com projetos genômicos, inovações incrementais, doenças negligenciadas e produtos naturais são apontados como áreas estratégicas. A afirmação de que o Brasil reúne as condições necessárias para participar do processo de desenvolvimento de fármacos - hipótese primária deste trabalho - encontra sustentação nos argumentos apresentados e revela que as condições para a inovação tecnológica nunca foram tão favoráveis quanto agora. Estimular o debate acerca de estratégias que possam fomentar o desenvolvimento científico e tecnológico da pesquisa e desenvolvimento de fármacos no país representa a contribuição almejada por este trabalho. / It can be asserted that in the twentieth century a multinational pharmaceutical industry with extraordinary research and development capacity to produce new drugs arose. However, contradicting this innovative potential, the number of new chemical entities introduced in the market is declining since 1960 and the opportunities open with the progresses of molecular biology, genomics, bioinformatics and chemistry haven\'t brought the expected results yet. In Brazil, the scientific research has been obtaining results of great relevance, but a lot of difficulty is found to introduce new products into the market. The main purpose of this work is to discuss fomentation strategies for the drug research and development in the country, trying to reconcile technical and economic requirements of this process with the pre-existent competences. The adopted methodological referential emphasizes the decisive role of economic relationships in drug research and development and tries to find out compatible ways with the national reality. For that, it discusses the technical and economic characteristics of this activity, as well as the strategy of innovative companies and some Brazilian experiences in this knowledge area. Based on the analysis of 766 new chemical entities introduced in world market among 1984 to 2003, in economic pillars of the innovation process and in political-institutional context of drug research and development, alternatives are proposed to straighten out the scientific and technological development of Brazilian pharmaceutical sector. Many activities related to the drug research and development are accomplished in the country, but they are scattered in the main universities, research centers and institutes. The charting of these competences represents the start up to create an innovation net in the pharmaceutical section. One of the bottlenecks identified in this work is the fragility of institutional support for high technology negotiations, of which patents, cooperation agreements and technology transference make part. To make it possible, in Brazil, incorporation of high technology tools used in drug development, creation of National Laboratory of Drug Research and Development was proposed. Besides guaranteeing technical sophistication, this National Laboratory would act as an open institution, multidisciplinary, shouldering the role of an articulation center of initiatives aiming drug development, being able to generate resources to finance research and to contribute to scientific and technological development. Cooperation agreements with innovative companies and international organisms are part of strategies to raise funds research fields aligned with the needs of the Brazilian Unique Health System (SUS) and with other policies of Public Sector also must direct the drug research and development in the country. New molecular targets evaluation articulated in genomic process, incremental innovations, neglected diseases and natural products are pointed out as strategic areas. The statement that Brazil has conditions of participating in the process of drug development - primary hypothesis of this work - finds back-up in reported arguments and reveals that conditions for technological innovation have never been as favorable as now. To stimulate the debate concerning strategies that can foment scientific and technological development of drug research and development in the country represents the contribution aimed for this work.

Orientador: Hérida Regina Nunes Salgado / Banca: Leticia Scherer Koester / Banca: Ian Castro Gamboa / Banca: Luis Vitor Silva do Sacramento / Banca: Marlus Chorilli / Resumo: Objetivou-se, neste trabalho, realizar um estudo químico-farmacológico, bem como o desenvolvimento de uma formulação galênica das folhas de Spondias dulcis Forst., conhecida popularmente como cajarana. Está planta apresenta uso popular como antiinflamatório e antisséptico. Inicialmente, foi feita uma avaliação farmacognóstica e microbiológica da droga. Em seguida, foram produzidos extratos hidroalcoólicos utilizando delineamento experimental e desenvolvido e validado um método para quantificação de polifenóis totais. O extrato hidroalcoólico foi avaliado em ensaios in vitro (atividade antimicrobiana e antioxidante) e in vivo (atividade laxante e toxicidade aguda). O componente majoritário foi identificado e isolado, utilizando técnicas de cromatografia em contracorrente e de espectroscopia. Por fim, foi desenvolvida e caracterizada uma dispersão sólida obtida com extrato e o polímero PVP K30 e avaliada sua estabilidade, utilizando cinética não isótermica. A droga vegetal foi caraterizada pela densidade aparente, tamanho de partícula, perda por dessecação, pH e teor de extrativos e controle microbiológico. A espectroscopia na região do infravermelho permitiu a identificação de grupamentos específicos provenientes de diversos metabólitos e a análise térmica identificou seis etapas de degradação. O extrato escolhido foi obtid por turboextração, utilizando a solução de 50% de etanol com 20% de droga vegetal. O método desenvolvido e validado para polifenóis totais apresentoi-se de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this work was to conduct a chemical-pharmacological study, as well as the development of a galenic formulation of the leaves of Spondias dulcis Forst., known as cajarana. This plant presents popular use as antiinflammatory and antiseptic. Initially, a pharmacological and microbiological evaluation of the herbal drug. Hydroalcoholic extracts were produced using experimental design and developed and validated a method for quantification of total polyphenols. The hydroalcoholic extract was evaluated in vitro tests (antimicrobial and antioxidant activity) and in vivo (laxative activity and acute toxicity). The main component, identified and isolated, countercurrent chromatography and spectroscopy techniques. Finally, a solid dispersion obtained with extract and the polymer PVP K30 was developed and characterized and its stability evaluated using non-isothermal kinetics. The herbal drug was characterized by apparent density, part size, desiccation loss, pH and extractive content and microbiological control. The infrared spectroscopy identified of specific data of several metabolites and a thermal analysis identified six stages of degradation. The extract were produced by turboextraction, use a solution of 50% ethanol with 20% plant drug. The method developed and validated for total polyphenols presented within the conformities in the figures of merit (selectivity, linearity, precision, accuracy and robustness). The pharmacological activity verified in the case of ... (Complete abstract click electronic access below) / Doutor

New drugs are needed for better cancer management. Clinical trials are currently underway to assess the use of flavonoids (natural polyphenols) as anticancer agents. Among them, myricetin has been shown to induce cell cycle arrest and apoptosis in pre-clinical cancer models. We hypothesised that myricetin-derived novel flavonoids designed to enhance this natural potential and improve on the drug-likeness limitations of myricetin might have increased potential for their application in the management of breast and ovarian cancer. The effect of a library of novel flavonoids was screened on 3 panels of breast and ovarian cancer cell lines, representing different molecular subtypes and phenotypes, to assess their potency. The second-generation bi-methoxylated analogue AO-1530-OMe (Oncamex) was identified as the most effective candidate in the library, with sub-micromolar concentrations exerting a strong antiproliferative effect across almost all models studied. Results suggested that changes in the hydroxylation profile, the addition of methoxylations and a decyl alkyl chain were some of the structure-activity relationships contributing to this improved efficacy. Plate assays showed 8 h treatment with Oncamex reduced cell viability and induced cytotoxicity and apoptosis, concomitant with caspase activation and PARP cleavage. Pre-incubation with an antioxidant partially blocked these effects, suggesting the possible involvement of ROS modulation in the mechanism of action of Oncamex. Fluorescence microscopy reported the quick and stable delivery of Oncamex to the mitochondria. Fluorescent probes showed that Oncamex can induce mitochondrial superoxide production at concentrations associated with its antiproliferative effects. Study of the electrochemical properties of Oncamex by cyclic voltammetry supported this. Differential gene expression analysis following a microarray experiment showed Oncamex induces changes in the expression of genes controlling cell cycle and apoptosis. Together with previous results, the findings from this analysis led to the postulation of a model for the mechanism of action of Oncamex: due to its enhanced reactivity and mitochondrial targeting, Oncamex can generate mitochondrial superoxide, leading to mitochondrial dysfunction, membrane permeabilisation and the activation of the JNK pathway and the transcription factor FOXO3, which together contribute to the induction of intrinsic apoptosis and the inhibition of proliferation. Further proliferation assays on cell culture models also reported enhanced effect of Oncamex when administered in combination with paclitaxel and TRAIL. These improved responses were observed in breast and ovarian cancer models, including cells lines characterised by their treatment-resistant phenotype. Cotreatment with Oncamex also improved the effect of tamoxifen on anti-oestrogen resistant LCC9 breast cancer cells. Results from preliminary in vivo studies in mice implanted with the MDA-MB-231 breast cancer xenograft were consistent with an antiproliferative effect of Oncamex (25mg/kg/day) in vivo, as treatment inhibited tumour growth and reduced the expression of the marker of proliferation Ki-67 without signs of systemic toxicity. Tissues from this experiment also allowed for preliminary in vivo validation of the proposed mechanism of action of Oncamex by immunohistochemistry. The in vivo cytostatic effect of Oncamex was confirmed in a second in vivo experiment, which also investigated the effect of Oncamex at higher doses or in combination with paclitaxel. In conclusion, the novel flavonoid Oncamex has shown a promising antiproliferative effect in pre-clinical models of breast and ovarian cancer, including models of treatment-resistant cancers. Preliminary in vivo studies have demonstrated a partial recapitulation of the effect of Oncamex. A mechanistic model has been proposed by which Oncamex induces intrinsic apoptosis through its redox reactivity and mitochondrial targeting. These results support the potential of this prototypic candidate, although possible work in the structure and formulation of this candidate and further study and validation of its mechanism of action is needed for its continued development as an anticancer agent.

Diseases which affect the central nervous system present a huge burden to sufferers and caregivers. In tandem with longevity, prevalences of age-related neurodegenerative diseases are increasing. However, despite the evident necessity for pharmaceutical interventions, there has been a distinct lack of drug development to combat these disorders. This is largely attributed to high financial costs of using rodent models. Thus the validation of a more cost-effective in vivo system would facilitate pharmaceutical screening. The work presented in this thesis addresses this issue by assessing the utility of zebra fish in two costly areas of translational neurobiology { lead identi cation and safety pharmacology. An aversive classical conditioning assay was developed and automated as a behavioural screening method. This robust assay allows fast assessment of cognition and cognitive decline. The effect of neurotoxin treatment on aversive learning was then assessed using this assay, demonstrating its efficacy as a screening tool for neurodegeneration research. Subsequently, a transgenic zebra fish line - expressing a mutated form of the Alzheimer's-associated human amyloid precursor protein - was assessed, demonstrating an age-related cognitive impairment. Additionally new genetic zebra fish lines were generated, which over-express genes (both endogenous and transgenic) related to Alzheimer's-like pathologies. Whilst these were not assessed within this thesis, they present promising tools for possible future investigations. Regarding safety pharmacology, regulatory bodies require all CNS-penetrant drugs be assessed for abuse potential. Zebra fish display reward responses to several common drugs of abuse (e.g. amphetamine, cocaine, morphine). Thus, the latter sections of this thesis evaluated the utility of zebra fish for assessing human abuse potential. A CPP paradigm was utilised to test a range of drugs, with the sensitivity and specificity of zebra fish compared to previous reports using rodent. Additionally, the development of a zebra fish drug discrimination assay was attempted. However the paradigms utilised failed to develop an efficacious assay.

The identification of drug treatments that are useful in diverse therapeutic settings is a significant driving force in biomedical research [Macarron et al., 2011], [Poureetezadi et al., 2014], [Lamb, 2007]. Typical means for measuring the efficacy of a drug for a given clinical application include protein-protein interactions, cell death, mitochondrial respiration and cell growth as well as broader measurements of absorption, distribution, metabolism, excretion and toxicity (ADMET), specifically related the the drug or drugs being tested [Szakcs et al., 2008]. A wide array of methods are routinely employed to perform these screens, from ligand binding assays [Wagner et al., 2016] to high-throughput proteomics [Verheul, 2014]. One method that is currently underutilized in small-molecule drug screens and drug discovery is high-throughput transcriptome sequencing, such as RNA-Seq. Although RNA-Seq is routinely used to profile patterns of genetic changes following perturbations such as drug treatment [Young et al., 2014], it has not, to my knowledge, yet been used as the primary readout of a drug screen.

INTRODUCTION: Melanoma is the most deadly skin cancer with mortality dependent on the extent and location of metastases. Lymphatic metastasis occurs early in melanoma, and tumor-associated lymphatic vessel area correlates with melanoma progression. Recently, the discovery of checkpoint inhibitors has drastically changed the treatment strategy and survival rates in melanoma. Neuropilin-2 (NRP2) is a potential common target in melanoma cells, tumor-associated lymphatic endothelial cells (LECs) and tumor-infiltrating lymphocytes (TILs). NRP2 is a cell surface receptor with competing stimulatory ligands (VEGF-A/-C) and inhibitory ligands (SEMA3F/G). AIM: The goal of this study was to investigate the role of NRP2 in both melanoma cells and the melanoma microenvironment (LECs, TILs) and to examine the effect of semaphorin 3F (SEMA3F) on the tumor cells as well as an immune modulator. RESULTS: Mouse and human melanocytes expressed NRP2 but not other vascular endothelial growth factor (VEGF) receptor tyrosine kinases in vitro and in vivo. NRP2 protein expression, as analyzed by immunohistochemistry, was upregulated in human metastatic melanoma sections. Treatment of melanoma cells in vitro with SEMA3F inhibited migration and phosphorylation of protein kinase B (AKT) but did not inhibit cell viability. SEMA3F also increased programmed cell death-ligand 1 (PD-L1) expression in melanoma. Syngeneic B16F10 melanoma did not grow in global NRP2 knockout (KO) mice but did grow in wild-type mice. In addition, mice inoculated with B16F10 were treated with SEMA3F or phosphate-buffered saline (PBS) by mini-osmotic pumps. Resulting tumors were analyzed histologically for microvessel density and presence of TILs (number and subtype). CONCLUSIONS: Expression of NRP2 protein positively correlated with melanoma progression in human patient samples. NRP2 functions differently in melanoma tumor cells than in host stromal cells (endothelial cells [ECs], LECs). In melanoma, NRP2 is not a VEGF receptor but responds to the ligand, SEMA3F. Alternately, NRP2 appears to be an important VEGF-A/-C co-receptor in tumor-associated angiogenesis and lymphangiogenesis, as demonstrated in the NRP2 transgenic mice studies. SEMA3F inhibited tumor cell migration but increased PD-L1 expression. Systemic treatment with purified SEMA3F protein in melanoma preclinical trials inhibited melanoma growth and microvessel density. Taken together, these results suggest that exploiting the NRP2/SEMA3F signaling axis may be a novel treatment strategy to be used in combination with existing immunotherapy in melanoma. / 2020-07-03T00:00:00Z

Tse, Ching Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (p. 188-200). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.vi / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Obtain information on drug targets --- p.3 / Chapter 1.2 --- Drug Design --- p.5 / Chapter 1.3 --- Interface for interaction --- p.9 / Chapter 1.4 --- Summary --- p.10 / Chapter 2 --- Background Study --- p.12 / Chapter 2.1 --- Protein Function Prediction --- p.16 / Chapter 2.2 --- Drug Design --- p.37 / Chapter 2.3 --- Visualisation and Interaction in Biomedic --- p.44 / Chapter 3 --- Overview --- p.48 / Chapter 3.1 --- Protein prediction using secondary structure analysis --- p.52 / Chapter 3.2 --- Knowledge-driven ligand design --- p.55 / Chapter 3.3 --- Interactive interface in virtual reality --- p.57 / Chapter 4 --- Protein Function Prediction --- p.60 / Chapter 4.1 --- Introduction --- p.61 / Chapter 4.1.1 --- Motivation --- p.61 / Chapter 4.1.2 --- Objective --- p.62 / Chapter 4.1.3 --- Overview --- p.63 / Chapter 4.2 --- Methods and Design --- p.66 / Chapter 4.2.1 --- Feature Cell --- p.68 / Chapter 4.2.2 --- Heterogeneous Vector --- p.71 / Chapter 4.2.3 --- Feature Cell Similarity --- p.75 / Chapter 4.2.4 --- Heterogeneous Vector Similarity --- p.79 / Chapter 4.3 --- Experiments --- p.85 / Chapter 4.3.1 --- Data Preparation --- p.85 / Chapter 4.3.2 --- Experimental Methods --- p.87 / Chapter 4.4 --- Results --- p.97 / Chapter 4.4.1 --- Scalability --- p.97 / Chapter 4.4.2 --- Cluster Quality --- p.99 / Chapter 4.4.3 --- Classification Quality --- p.102 / Chapter 4.5 --- Discussion --- p.103 / Chapter 4.6 --- Conclusion --- p.104 / Chapter 5 --- Drug Design --- p.106 / Chapter 5.1 --- Introduction --- p.107 / Chapter 5.1.1 --- Motivation --- p.107 / Chapter 5.1.2 --- Objective --- p.109 / Chapter 5.1.3 --- Overview --- p.109 / Chapter 5.2 --- Methods --- p.111 / Chapter 5.2.1 --- Fragment Joining --- p.115 / Chapter 5.2.2 --- Genetic Operators --- p.116 / Chapter 5.2.3 --- Post-Processing --- p.124 / Chapter 5.3 --- Experiments --- p.128 / Chapter 5.3.1 --- Data Preparation --- p.129 / Chapter 5.3.2 --- Experimental Methods --- p.132 / Chapter 5.4 --- Results --- p.134 / Chapter 5.4.1 --- Binding Pose --- p.134 / Chapter 5.4.2 --- Free Energy and Molecular Weight --- p.137 / Chapter 5.4.3 --- Execution Time --- p.138 / Chapter 5.4.4 --- Handling Phosphorus --- p.138 / Chapter 5.5 --- Discussions --- p.139 / Chapter 5.6 --- Conclusion --- p.140 / Chapter 6 --- Interface in Virtual Reality --- p.142 / Chapter 6.1 --- Introduction --- p.143 / Chapter 6.1.1 --- Motivation --- p.143 / Chapter 6.1.2 --- Objective --- p.145 / Chapter 6.1.3 --- Overview --- p.145 / Chapter 6.2 --- Methods and Design --- p.146 / Chapter 6.2.1 --- Hybrid Drug Synthesis --- p.147 / Chapter 6.2.2 --- Interactive Interface in Virtual Reality --- p.154 / Chapter 6.3 --- Experiments and Results --- p.171 / Chapter 6.3.1 --- Data Preparation --- p.171 / Chapter 6.3.2 --- Experimental Settings --- p.172 / Chapter 6.3.3 --- Results --- p.173 / Chapter 6.4 --- Discussions --- p.176 / Chapter 6.5 --- Conclusions --- p.179 / Chapter 7 --- Conclusion --- p.180 / A Glossary --- p.184 / Bibliography --- p.188

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

No description available.