Die vorliegende Arbeit behandelt das biologische Phänomen der Dormanz mit Hilfe mathematischer Modellierung. Dormanz beschreibt dabei einen reversiblen Zustand von Individuen, in dem die metabolische Aktivität reduziert wird und die Resistenz gegen Natureinflüsse erhöht ist. Der erste Teil der Arbeit widmet sich den ökologischen Eigenschaften. Hier wird zunächst ein Moranmodell vorgestellt, welches verschiedene Modellierungsarten von Dormanz aus der Populationsgenetik vereint und unter verschiedenen Skalierungen den schwachen seed-bank Koaleszenten und den starken seed-bank Koaleszenten als anzestralen Prozess innehat. Dadurch werden die Parameter der Koaleszenten vergleichbar. Als Anwendung betrachten wir die sogenannte species abundance distribution, welche mithilfe von Koaleszenten beschrieben werden kann. Der zweite Teil beschäftigt sich mit den Auswirkungen von Dormanz auf evolutionäre Eigenschaften und beginnt mit einer Einführung in die Theorie von adaptive dynamics. Dort werden auch verschiedene Möglichkeiten der Modellierung von Dormanz in individuenbasierten Modellen besprochen. Danach befassen wir uns mit der Erweiterung eines Modells für sympatrische Speziation um den Aspekt der Dormanz. Die canonical equation of adaptive dynamics wird - motiviert durch ein Modell mit Dormanz - für schnellere Mutationsraten aus dem sogenannten power-law Mutationsregime für einen Grenzfall hergeleitet. Die Arbeit schließt mit dem dritten Teil, in welchem ein individuenbasiertes Modell für die Entwicklung von Krebs unter dem Einfluss von Chemotherapie und unter Berücksichtigung von Dormanz vorgestellt wird. In Simulationsstudien wird untersucht, inwiefern Dormanz zu Misserfolg einer Therapie beiträgt. Ein weiteres Ziel ist die Analyse von Kombinationsbehandlung mit einem Medikament welches mit dormanten Zellen interagieren kann insbesondere unter Betrachtung verschiedener Therapieansätze zur Behandlung von dormanten Krebszellen. / The present thesis uses mathematical modelling to investigate the consequences of dormancy. Dormancy describes a reversible and protected state of reduced metabolic activity which enhances an individual's resilience to hazardous conditions. In this sense, dormancy acts as a protection mechanism against habitats with unfavourable environments. The thesis considers the impact of dormancy on ecological, evolutionary and in its broadest sense pathogenic properties of microbial populations. The first part is concerned with studying the impact of dormancy on ecology. For this, a Moran model is presented which unifies different models of dormancy from population genetics and exhibits the weak seed-bank coalescent and the strong seed-bank coalescent as the scaling limit of the ancestral process. As an application we consider the species abundance distribution which can be described using coalescent theory. In the second part we consider the influence of dormancy on evolutionary properties. The modelling framework for this is the theory of adaptive dynamics. We then show that competition-induced dormancy may favour sympatric speciation. A key aspect in the derivation of this result is the canonical equation of adaptive dynamics. We extend this equation - motivated by a model including dormancy - to power-law mutations in a limiting case. We conclude the thesis with the third part where we provide an individual-based model for the treatment of cancer with chemotherapy under consideration of dormant cancer cells. Using simulation studies, we investigate how dormancy may contribute to treatment failure. Another goal of this chapter is to analyse combination treatment with a drug which directly targets dormant cancer cells and to formulate general observations regarding various strategies to counter cancer cell dormancy.

DNA is wrapped around proteins called histones, whose modification regulates numerous cellular processes. Therefore it is not surprising that mutations in the genes that modify the histones are frequently associated with human cancer. For example, mutations in SETD2, encoding the sole enzyme that catalyses histone H3 lysine 36 trimethylation (H3K36me3), occur frequently in multiple cancer types. This identifies H3K36me3 loss as an important event in cancer development, and also as a potential therapeutic target. This thesis investigates the following questions: (1) how does the loss of H3K36me3 contribute to cancer development; and (2) what therapy can be used to kill cancers that have already lost H3K36me3. To answer the first question, this thesis shows that H3K36me3 facilitates the accurate repair of DNA double-stranded breaks (DSBs) by homologous recombination (HR). H3K36me3 promotes HR by recruiting CtIP to the site of DSBs to carry out resection, allowing the binding of HR proteins (such as RPA and RAD51) to the damage sites. Thus it is proposed that error-free HR repair within H3K36me3-decorated transcriptionally active genomic regions suppresses genetic mutations which could promote tumourigenesis. To answer the second question, this thesis reveals a clinically relevant synthetic lethal interaction between H3K36me3 loss and WEE1 inhibition. WEE1 inhibition selectively kills H3K36me3-deficient cells by inhibiting DNA replication, and subsequent fork stalling results in MUS81 endonuclease-dependent DNA damage and cell death. The mechanism is found to be synergistic depletion of RRM2 (ribonucleotide reductase small subunit), the enzyme that generates deoxyribonucleotides (dNTPs). This work reveals two pathways that regulate RRM2: one involves transcriptional activation of RRM2 by H3K36me3, and the other involves RRM2 degradation regulated by Cyclin-Dependent Kinase, CDK1 (which is controlled by WEE1, CHK1 and ATR). Based on this mechanism, the synthetic lethal interaction is expanded, from between two genes, to between two pathways. Supported by in vivo experiments, the study suggests that patients with cancers that have lost H3K36me3 could benefit from treatment with the inhibitors of WEE1, CHK1 or ATR.

Das Zytokin Interleukin-7 (IL-7) ist für die Entstehung und das Überleben reifer T Zellen von zentraler Bedeutung. Die Gabe von IL-7 führt sowohl in der Maus als auch im Menschen zu erhöhten T Zellzahlen und einem veränderten T Zellphänotyp. Folglich könnte sich die therapeutische Gabe von IL-7 bei Patienten mit geschwächtem Immunsystem positiv auswirken. Diese Hypothese wird derzeit in mehreren klinischen Studien untersucht. Bisher wurde allerdings nur die Wirkung von IL-7 auf T-Zellen studiert. Zu dessen Wirkung auf andere Immun- oder Stromazellen sowie deren IL-7-abhängigen Beitrag zur Regulation der T-Zellhomöostase ist nur wenig bekannt. Daher war es Ziel der Arbeit, den Einfluss einer therapeutischen Gabe von IL-7 auf adoptiv-transferierte T-Zellen in IL-7-Rezeptor (IL-7R)-kompetenten und defizienten lymphopenischen Mäusen zu studieren. Die Untersuchungen bestätigen, dass die Gabe von IL-7 T-Zellantworten unterstützt, zeigen jedoch auch, daß viele dieser Effekte von IL-7R-exprimierenden Wirtszellen abhängig sind. Dies weist darauf hin, dass IL-7R-vermittelte Signale in Wirtszellen indirekt T-Zellantworten beeinflussen. Zudem zeigte sich, dass effiziente anti-Tumor-T Zellantworten von IL 7R-vermittelten Signalen in Wirtszellen abhängen. Vor allem nicht-hämatopoetische Wirtszellen fungieren hier als Regulatoren der IL-7-Therapie-vermittelten T Zelldifferenzierung. Unsere Ergebnisse bestätigen außerdem, dass Stromazellen in verschiedenen Organen il-7 exprimieren und zeigen darüber hinaus, dass diese Zellen durch die Gabe von IL-7 beeinflusst werden. Wir folgern daraus, dass die Effekte der IL-7-Therapie auf T Zellhomöostase teilweise indirekt über il-7-exprimierende Stromazellen vermittelt werden. Um diese Zellen genauer identifizieren und untersuchen zu können, haben wir ein neues transgenes Mausmodell charakterisiert, was es erleichtern wird, die beteiligten molekularen Signalwege zu analysieren und den Erfolg der adoptiven T Zelltherapie zu verbessern. / Interleukin-7 (IL-7) is an essential cytokine required for the development and maintenance of mature T cell. Its availability is limited under normal conditions, but rises during lymphopenia, leading to increased T cell proliferation. The administration of recombinant IL-7 to normal or lymphopenic mice and humans results in increased T cell numbers and altered T cell phenotype. Hence, IL-7 administration could mediate therapeutic benefits in immunocompromised patients and is currently tested in several clinical trials. However, besides its well-studied effects on T cells little is known about the effect of IL-7 on other immune and non-immune cells and their influence on T cell homeostasis. Therefore, we evaluated the effect of IL-7 therapy on adoptively transferred T cells in IL-7 receptor (IL-7R)-competent and IL-7R-deficient lymphopenic mice. We confirm the benefits of IL-7 therapy on T cell responses but additionally show that many of these effects are dependent on IL-7R expression by host cells, indicating that IL-7R signaling in host cells modulates T cell responses. We show that efficient T cell responses against cancer are dependent on host IL-7R signaling. Based on studies in bone-marrow chimeric mice, we identify non-hematopoietic host cells as main regulators of IL-7 therapy-modulated T cell differentiation. We conclude from these data that IL-7 therapy affects non-hematopoietic stromal cells that modulate the success of adoptive T cell therapy. Our results confirm that stromal cells in various organs express il-7 and show that these cells are targeted by IL-7 therapy in vivo. Hence, we propose that il-7-expressing cells regulate IL-7 therapy-modulated T cell homeostasis. To identify and study these il-7 expressing stromal cells in more detail, we characterized a new transgenic mouse model that will facilitate determining the molecular pathways to improve the success of adoptive T cell therapy.

No Brasil, o Sistema de Saúde é Universalista, com o tratamento integral gratuito ao paciente com câncer, cujo direito é assegurado por Lei e regulamentado pelo Ministério da Saúde / Instituto Nacional de Câncer José Alencar Gomes da Silva (INCA), por meio de Decreto Presidencial e Portarias. A habilitação e credenciamento de Hospitais em Unidades ou Centros de Alta Complexidade em Oncologia segue critérios rígidos, que determina como sendo obrigatória a presença do Cirurgião-Dentista na equipe multiprofissional e multidisciplinar na oncoterapia. O tratamento odontológico é compulsório e imprescindível na terapia antineoplásica, para prevenir e tratar as complicações orais: hemorragia, infecção, mucosite oral, xerostomia, cárie de radiação, trismo, alterações periodontais, osteonecrose avascular, osteorradionecrose; que podem levar à interrupção da oncoterapia, acarretando um aumento considerável nos custos da terapia implementada, a piora da qualidade de vida, e em alguns casos, podendo levar o paciente a óbito. O protocolo de cuidados orais na oncoterapia é normatizado e padronizado pelo INCA. Desta forma, foi realizado estudo do tratamento odontológico em pacientes com diagnóstico de câncer atendidos no Serviço de Odontologia Oncológica do UNACON do Hospital Geral de Palmas/Tocantins, no período de abril de 2011 a dezembro de 2016. Os dados foram obtidos de forma individualizada e estruturados segundo Variáveis Demográficas (VD), Procedimento Odontológico (PO), Procedimento Odontológico por Dente (POD) e Outras Variáveis de Interesse (OVI). O impacto financeiro de PO e POD foi avaliado pela comparação entre a tabela SIGTAP do Sistema Único de Saúde (SUS) e a tabela VRPO/SOESP (Valores Referenciais para Procedimentos Odontológicos/Sindicato dos Odontologistas do Estado de São Paulo). A maior incidência de pacientes foi observada na 5ª década de vida, com tendência à proporção homem/mulher de 1:1. Foram realizados 910 procedimentos preventivos/profilaxia/atividade educativa; 1826 raspagens supra e subgengival e aplicação tópica de flúor por hemiarcada; 932 restaurações de uma e duas faces com resina fotopolimerizável; 909 exodontias; 2746 sessões de laserterapia de baixa potência. O impacto financeiro mostrou uma defasagem significativa da Tabela SIGTAP/SUS. O estudo realizado revela a importância de uma base de dados estruturada para o registro do tratamento odontológico realizado em pacientes com diagnóstico de câncer atendidos no Sistema Único de Saúde; para que com isso seja possível fomentar, nos Sistemas de Saúde no Mundo, a elaboração e padronização de protocolo de cuidados orais na terapia antineoplásica, e o planejamento dos recursos humanos e financeiros destinados ao tratamento odontológico nos pacientes oncológicos. / In Brazil, the Health System is Universalist, with free comprehensive treatment for the cancer patient, whose right is guaranteed by Law and regulated by the Ministry of Health / National Cancer Institute José Alencar Gomes da Silva (INCA), through a Presidential Decree and Ordinances. The accreditation of Hospitals in Units or Centers of High Complexity in Oncology follows rigid criteria, which determines as mandatory the presence of the Dentist in the multiprofessional and multidisciplinary team in oncotherapy. Dental treatment is compulsory and essential in antineoplastic therapy to prevent and treat oral complications: hemorrhage, infection, oral mucositis, xerostomia, radiation caries, trismus, periodontal changes, avascular osteonecrosis, osteorradionecrosis; which can lead to interruption of oncotherapy, leading to a considerable increase in the costs of the therapy implemented, worsening of quality of life, and in some cases, leading to death. The protocol of oral care in oncotherapy is standardized by INCA. In this way, a study of the dental treatment was carried out in patients diagnosed with cancer attended at the UNACON Oncological Dentistry Service of the General Hospital of Palmas / Tocantins, from april 2011 to december 2016. Data were obtained individually and structured according to Demographics Variables (VD), Dental Procedure (PO), Dental Procedure by Tooth (POD) and Other Variables of Interest (OVI). The financial impact of PO and POD was evaluated by comparing the SIGTAP table of the Unified Health System (SUS) and the VRPO / SOESP table (Reference Values for Dental Procedures / Union of Dental Practitioners of the State of São Paulo). The highest incidence of patients was observed in the 5th decade of life, with a tendency to male to female ratios of 1: 1. Nine hundred and ten (910) preventive procedures / prophylaxis / educational activity were carried out; 1826 supra and subgingival scaling and topical application of fluoride by hemiarcate; 932 single and double sided restorations with photopolymerizable resin; 909 exodontia; 2746 sessions of low power laser therapy. The financial impact showed a significant lag in the SIGTAP / SUS Table. The study reveals the importance of a structured database for the registry of dental treatment performed in patients diagnosed with cancer treated in the Unified Health System; so that it is possible to promote, in the World Health Systems, the elaboration and standardization of oral care protocol in antineoplastic therapy, and the planning of human and financial resources for dental treatment in cancer patients.

Broad distribution and activity limit the utility of anti-cancer compounds by causing unacceptable systemic toxicity and narrow therapeutic indices. To improve tumour accumulation, drug-loaded macromolecular assemblies have been designed to replace conventional surfactant-based formulations. Their nanoscale size enhances tumour accumulation via hyperpermeable vasculature and reduced lymphatic drainage. Incorporating targeting ligands introduces cell specificity through receptor-specific binding and uptake, enabling drugs to reach intracellular targets. In this work, the targeting properties of polymer nanoparticle micelles of poly(2-methyl-2-carboxytrimethylene carbonate-co-D,L-lactide)-graft-poly(ethylene glycol)-furan (poly(TMCC-co-LA)-g-PEG) were verified using in vitro and in vivo models of breast cancer. To select a relevant mouse model, the vascular and lymphovascular properties of two tumour xenograft models were compared. Greater accumulation of a model nanocarrier was observed in orthotopic mammary fat pad (MFP) tumours than size matched ectopic subcutaneous tumours, suggesting that the organ environment influenced the underlying pathophysiology. Immunostaining revealed greater vascular thickness, density and size, and thinner basement membranes in MFP tumours, likely contributing to greater blood perfusion and vascular permeability. Based on these observations, MFP tumour-bearing mice were used to characterize the pharmacokinetics and biodistribution of a taxol drug, docetaxel, encapsulated in poly(TMCC-co-LA)-g-PEG nanoparticles. The nanoparticle formulation demonstrated longer docetaxel circulation in plasma compared to the conventional surfactant-based formulation. As a result, greater docetaxel retention was uniquely measured in tumour tissue, extending exposure of tumour cells to the active compound and suggesting potential for increased anti-cancer efficacy. Furthermore, active targeting of antibody-modified nanoparticles to live cells was shown to be selective and receptor-specific. Binding isotherms were used to quantify the impact of antibody density on binding strength. The equilibrium binding constant increased linearly with the average number of antibodies per particle, which is consistent with a single antibody-antigen interaction per particle. This mechanistic understanding enables binding behaviour to be adjusted in a predictive manner and guides rational nanoparticle design. These studies validate poly(TMCC-co-LA)-g-PEG nanoparticles as a platform for targeted delivery to cancer on both a tissue and cellular level, forming a compelling justification for further pre-clinical evaluation of this system for safety and efficacy in vivo.

Herkömmliche Zytostatika greifen vornehmlich in den Zellzyklus ein und somit werden Zellen mit hoher Proliferationsrate geschädigt. Allerdings fallen hierunter nicht ausschließlich Krebszellen, sondern auch gesunde, schnell proliferierende Gewebearten. Auf Grund dessen verursacht eine klassische Chemotherapie schwerwiegende Nebenwirkungen. Neuere Therapieansätze greifen daher geno- sowie phänotypischer Unterschiede zwischen malignen und gesunden Zellpopulationen auf und können selektiv den zytotoxischen Wirkstoff in die Tumorpopulation einbringen. Dazu werden sogenannte Prodrug-Konzepte verfolgt, bei denen ein möglichst „untoxisches” Prodrug gezielt im entarteten Gewebe enzymatisch zum zytotoxischen Wirkstoff (Drug) aktiviert wird. In diesem Rahmen werden Substrate für die Antibody-Directed Enzyme Prodrug Therapy (ADEPT) hergestellt. Bei diesem Konzept wird eine hohe Tumorspezifität durch Konjugate aus Enzymen und Antikörpern erlangt, indem das Immunglobulin selektiv an tumorassoziierte Antigene bindet und durch das konjugierte Enzym die Drugfreisetzung ermöglicht wird. Die natürlichen zytotoxischen Antibiotika (+)-CC 1065 und (+)-Duocarmycin SA dienen hierbei als Leitstrukturen für die Synthese entsprechender Prodrugs. Im Rahmen der vorliegenden Arbeit wurden insgesamt zwei neue Duocarmycin-analoge Prodrugs sowie neun neue seco-Drugs synthetisiert, wobei vier Vertreter eine terminale Alkinfunktion aufweisen. Für die Darstellung der Prodrugs wurden auf die Galaktose als Glykosideinheit zurückgegriffen. Zudem wurde ein neuartiges dimeres seco Drug hergestellt, das aus zwei pharmakophoren Einheiten sowie einem verbrückenden Linker mit Alkineinheit besteht. Die jeweiligen Substanzen wurden auf ihre In-vitro-Zytotoxizitäten sowie die Eignung für eine Anwendung im ADEPT-Ansatz evaluiert. Neun der neuen Duocarmycin-Analoga wurden in Form von seco- und Prodrugs wurden im Rahmen des aktivitätsbasierten Protein-Profilings untersucht. Hierbei konnte die Aldehyddehydrogenase 1 als wichtiges Angriffsziel der Duocarmycin-Familie verifiziert werden.

Broad distribution and activity limit the utility of anti-cancer compounds by causing unacceptable systemic toxicity and narrow therapeutic indices. To improve tumour accumulation, drug-loaded macromolecular assemblies have been designed to replace conventional surfactant-based formulations. Their nanoscale size enhances tumour accumulation via hyperpermeable vasculature and reduced lymphatic drainage. Incorporating targeting ligands introduces cell specificity through receptor-specific binding and uptake, enabling drugs to reach intracellular targets. In this work, the targeting properties of polymer nanoparticle micelles of poly(2-methyl-2-carboxytrimethylene carbonate-co-D,L-lactide)-graft-poly(ethylene glycol)-furan (poly(TMCC-co-LA)-g-PEG) were verified using in vitro and in vivo models of breast cancer. To select a relevant mouse model, the vascular and lymphovascular properties of two tumour xenograft models were compared. Greater accumulation of a model nanocarrier was observed in orthotopic mammary fat pad (MFP) tumours than size matched ectopic subcutaneous tumours, suggesting that the organ environment influenced the underlying pathophysiology. Immunostaining revealed greater vascular thickness, density and size, and thinner basement membranes in MFP tumours, likely contributing to greater blood perfusion and vascular permeability. Based on these observations, MFP tumour-bearing mice were used to characterize the pharmacokinetics and biodistribution of a taxol drug, docetaxel, encapsulated in poly(TMCC-co-LA)-g-PEG nanoparticles. The nanoparticle formulation demonstrated longer docetaxel circulation in plasma compared to the conventional surfactant-based formulation. As a result, greater docetaxel retention was uniquely measured in tumour tissue, extending exposure of tumour cells to the active compound and suggesting potential for increased anti-cancer efficacy. Furthermore, active targeting of antibody-modified nanoparticles to live cells was shown to be selective and receptor-specific. Binding isotherms were used to quantify the impact of antibody density on binding strength. The equilibrium binding constant increased linearly with the average number of antibodies per particle, which is consistent with a single antibody-antigen interaction per particle. This mechanistic understanding enables binding behaviour to be adjusted in a predictive manner and guides rational nanoparticle design. These studies validate poly(TMCC-co-LA)-g-PEG nanoparticles as a platform for targeted delivery to cancer on both a tissue and cellular level, forming a compelling justification for further pre-clinical evaluation of this system for safety and efficacy in vivo.

La compréhension des mécanismes moléculaires de différentes pathologies a permis la caractérisation de gènes et de protéines impliqués dans la pathogénèse et l'identification de cibles thérapeutiques intracellulaires. La nature hydrophobique de la membrane cellulaire empêche le passage des médicaments dans les cellules. Les Cell-Penetrating Peptides (CPP) ou domaines de transduction protéiques (PTD) sont des peptides qui permettent l'internalisation de macromolécules hydrophiles in cellulo et in vivo. Un nouveau peptide issu du facteur de transcription ZEBRA du virus Epstein-Barr, et qui possède des propriétés de transduction a été caractérisé récemment dans notre laboratoire. Des études par mutagénèse de délétion de la protéine ZEBRA ont permis d'identifier la région d'acides aminés (nommé ainsi MD) impliquée dans la pénétration cellulaire. Ce peptide traverse les membranes des cellules de mammifères par un mécanisme de translocation directe, même lorsqu'il est fusionné à des molécules telles que la protéine reportrice eGFP. Le mécanisme de pénétration directe représente un grand avantage pour les applications thérapeutiques: les molécules cargos peuvent être internalisées directement dans le cytoplasme cellulaire sans dégradation et sous une forme biologiquement active. L'objectif de cette thèse est d'étudier les propriétés de pénétration cellulaire du peptide MD et d'évaluer ses applications thérapeutiques comme système de vectorisation des protéines. Ce travail est structuré en trois parties. La première partie porte sur l'étude de l'optimisation de la séquence peptidique MD par réduction de taille et l'évaluation du rôle de sa composition en acides aminés dans le processus de translocation à travers la membrane cellulaire. Cette étude a conduit à l'identification d'une séquence plus courte MD (MD11) possédant une efficacité et un mécanisme de translocation inchangés. La deuxième partie décrit une approche thérapeutique basée sur MD11 visant à la complémentation protéique d'un dysfonctionnement identifiée dans la plupart des cancers. Les cellules tumorales présentent des altérations dans la machinerie de traduction résultant dans une prolifération cellulaire incontrôlée. Parmi les différents facteurs intervenant dans la régulation de ce processus, le facteur eucaryote d'initiation 3 (eIF3) contribue à l'oncogenèse et au maintien de l'état cancéreux. Ce complexe est composé de 13 sous-unités, désignées eIF3 a-m. L'expression de certaines sous-unités est altérée dans plusieurs cancers, et en particulier la sous-unité f (eIF3f) est significativement diminuée dans le mélanome, les cancers du pancréas, de la vulve, du sein, de l'intestin et de l'ovaire. L'expression ectopique par transfection transitoire du gène eIF3f inhibe la synthèse protéique et induit l'apoptose dans le mélanome et dans les cellules cancéreuses pancréatiques. A partir de ces observations, nous avons développé une approche thérapeutique innovante pour le traitement des cancers dans lesquels la protéine manquante eIF3f est produite sous forme recombinante fusionnée à la séquence de MD11, et ensuite internalisée dans les cellules cibles tumorales. Ces résultats démontrent que le système de transfert de eIF3f basé sur MD11 représente une stratégie efficace pour supprimer la prolifération des cellules tumorales. La dernière partie de cette thèse explore la propriété de pénétration de MD11 dans les cellules de levure, et en particulier dans le champignon pathogène Candida albicans. Les résultats obtenus démontrent la polyvalence de MD11, qui fonctionne comme vecteur de protéines à activité biologique aussi bien dans la levure que dans les cellules de mammifères. Le potentiel de MD11 comme système de transport et de relargage des protéines a donc été établis, toutefois certaines améliorations en ce qui concerne la formulation des protéines de fusion et des études in vivo doivent être réalisées afin de valider son efficacité thérapeutique. / In recent years, the understanding of disease molecular mechanisms has led to the identification of genes and proteins that are altered in disease state and many therapeutic targets have been found located within cells. The protective and hydrophobic nature of plasma membrane prevents therapeutic drugs from entering cells. Cell-penetrating peptides (CPPs) or protein transduction domains (PTDs) have emerged as a group of non-invasive delivery vectors for various hydrophilic macromolecules, and several in vitro and in vivo applications as pharmaceutical carriers have been reported. A novel cell-penetrating peptide deriving from the Epstein-Barr virus ZEBRA transcription factor has been recently characterized in our laboratory. A reductionist study of full-length ZEBRA protein has allowed to identify the amino acid region (named as Minimal Domain, MD) implicated in cellular uptake. This peptide is able to cross the mammalian cell membranes via a direct translocation mechanism even when fused to cargo molecules such as eGFP reporter protein. The direct penetration mechanism represents a great advantage for therapeutic applications as the cargo molecules can be directly delivered into cells cytoplasm in a biological active form. The aim of this thesis is to explore the cell-penetrating properties of the MD peptide and evaluate its applications as therapeutic protein delivery system. This work is structured in three parts.The first part describes the study on the optimization of MD peptide sequence by size-reduction and the evaluation of its amino acid composition role in the translocation process across the cell membrane. This study has led to the identification of a shorter MD sequence (MD11) with unvaried mechanism of translocation. The second section describes a MD11-based therapeutic approach aiming at repair a dysfunction of the protein synthesis identified in most cancers. The regulation of the protein synthesis has a crucial role in governing the eukaryotic cell growth and subtle defects in the translational machinery can alter the cellular physiology and lead to cell malignancy. Among the different factors intervening in the regulation of this process, the eukaryotic initiation factor 3 (eIF3) contributes to oncogenesis and maintenance of the cancer state. This complex is composed of 13 subunits (designated eIF3 a-m). The expression of eIF3 subunits is altered in several cancers, and in particular the f subunit (eIF3f) is significantly down-regulated in pancreas, vulva, breast, melanoma, ovary and small intestine tumors. The eIF3f ectopic expression by transient gene transfection inhibits cellular protein synthesis and induces apoptosis in melanoma and pancreatic cancer cells. Starting from these observations, we developed an innovative therapeutic approach for cancer treatment in which the missing eIF3f protein is produced in vitro in fusion to MD11, and delivered to cells. These results have demonstrated that the MD11- based eIF3f transfer system may represent a powerful strategy to suppress the tumor-cell proliferation. The last part of this thesis explores the cell-penetrating property of MD11 in yeast cells, and in particular in the pathogenic fungus Candida albicans. The presented results demonstrate the versatility of MD11, functioning as vectors in both yeast and mammalian cells and as carrier for proteins with biological activity.The MD11 potential as protein delivery system is evident; however some improvements regarding the fusion protein formulation and in vivo studies should be realized to validate the effectiveness of its therapeutic application.

L’un des enjeux majeurs en nanomédecine est de développer des systèmes capables à la fois de permettre un diagnostic efficace et également de servir de plateforme thérapeutique pour combattre les infections et les neuro-dégénérescences. Dans cette optique, et afin d’améliorer la détection de tumeurs, des agents de contraste ont été développés dans le but d’augmenter le rapport signal sur bruit. Parmi ces agents, les nanoparticules (NPs) d’oxyde de fer superparamagnétiques (SPIOs) et les quantum dots (QDs) sont des candidats idéaux et ont reçu une grande attention depuis une vingtaine d’années. De surcroit, leurs propriétés spécifiques dues à leurs dimensions nanométriques et leurs formes permettent de moduler leur bio-distribution dans l’organisme. L’opportunité de revêtir ces NPs biocompatibles par des couches de polymères devraient permettre d’améliorer la stabilité de ces nanomatériaux dans l’organisme. Et par conséquent, favoriser leur biodistribution et également leur conférer de nouvelles applications en l’occurrence des applications biomédicales. Dans ce travail de thèse, nous avons développé de nouveaux systèmes thermo-répondant basés sur un cœur SPIOs ou QDs qui sont capables, à la fois, de transporter un principe actif anticancéreux, i.e. la doxorubicine (DOX) et de le relarguer dans le milieu physiologique à une température contrôlée. Deux familles de NPs ont été synthétisées. La première concerne des NPs de Fe3O4 SPIO qui ont été modifiées en surface par un copolymère thermorépondant biocompatible à base de 2-(2-methoxy) méthacrylate d’éthyle (MEO2MA), oligo (éthylène glycol) méthacrylate (OEGMA). La seconde famille, consiste en des NPs de ZnO recouverte du même copolymère. Pour la première fois, le copolymère de type P(MEO2MAX-OEGMA100-X) a été polymérisé par activateur-régénéré par transfert d’électron-polymérisation radicalaire par transfert d’atome (ARGET-ATRP). La polymérisation et copolymérisation ont été initiées à partir de la surface. Les NPs cœur/coquilles ont été caractérisées par microscopie électronique à transmission (TEM), analyse thermogravimétrique (TGA), etc. Nous avons montré que l’efficacité du procédé ARGET-ATRP pour modifier les surfaces des NPs de SiO2, Fe3O4 et de ZnO. L’influence de la configuration de la chaîne de copolymère et des propriétés interfaciales avec le solvant ou le milieu biologique en fonction de la température a été étudiée. Nous avons montré que les propriétés magnétiques des systèmes coeur/coquilles à base de Fe3O4 ne sont influencées que par la quantité de polymère greffée contrairement au QDs qui vient leur propriété optique réduire au-delà de la température de transition. Ce procédé simple et rapide que nous avons développé est efficace pour le greffage de nombreux copolymères à partir de surfaces de chimie différentes. Les expériences de largage et relarguage d’un molécule modèle telle que la DOX ont montré que ces nanosystèmes sont capables de relarguer la DOX à une température bien contrôlée, à la fois dans l’eau que dans des milieux complexes tels que les milieux biologique. De plus, les tests de cytocompatibilité ont montré que les NPs coeur/coquilles ne sont pas cytotoxiques en fonction de leur concentration dans le milieu biologique. A partir de nos résultats, il apparaît que ces nouveaux nanomatériaux pourront être envisagés comme une plateforme prometteuse pour le traitement du cancer / One of the major challenges in nanomedicine is to develop nanoparticulate systems able to serve as efficient diagnostic and/or therapeutic tools against sever diseases, such as infectious or neurodegenerative disorders. To enhance the detection and interpretation contrast agents were developed to increase the signal/noise ratio. Among them, Superparamagnetic Iron Oxide (SPIO) and Quantum Dots (QDs) nanoparticles (NPs) have received a great attention since their development as a liver contrasting agent 20 years ago for the SPIO. Furthermore, their properties, originating from the nanosized dimension and shape, allow different bio-distribution and opportunities beyond the conventional chemical imaging agents. The opportunity to coat those biocompatible NPs by a polymer shell that can ensure a better stability of the materials in the body, enhance their bio-distribution and give them new functionalities. It has appeared then that they are very challenging for medicinal applications. In this work, we have developed new responsive SPIO and QDs based NPs that are able to carry the anticancer drug doxorubicin (DOX) and release it in physiological media and at the physiological temperature. Two families of NPs were synthesized, the first one consist in superparamagnetic Fe3O4 NPs that were functionalized by a biocompatible responsive copolymer based on 2-(2-methoxy) ethyl methacrylate (MEO2MA), oligo (ethylene glycol) methacrylate (OEGMA). The second family consists in the ZnO NPs coated by the same copolymer. For the first time, P(MEO2MAX-OEGMA100-X) was grown by activator regenerated by electron transfer–atom radical polymerization (ARGET-ATRP) from the NPs surfaces by surface-initiated polymerization. The core/shell NPs were fully characterized by the combination of transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and by the physical properties of the nanostructures studied. We demonstrate the efficiency of the ARGET-ATRP process to graft polymers and copolymers at the surface of Fe3O4 and ZnO NPs. The influence of the polymer chain configuration (which leads to the aggregation of the NPs above the collapse temperature of the copolymer (LCST)) was studied. We have demonstrated that the magnetic properties of the core/shell Fe3O4-based nanostructures were only influenced by the amount of the grafted polymer and no influence of the aggregation was evidenced. This simple and fast developed process is efficient for the grafting of various co-polymers from any surfaces and the derived nanostructured materials display the combination of the physical properties of the core and the macromolecular behavior of the shell. The drug release experiments confirmed that DOX was largely released above the co-polymer LCST. Moreover, the cytocompatibility test showed that those developed NPs do not display any cytotoxicity depending on their concentration in physiological media. From the results obtained, it can be concluded that the new nanomaterials developed can be considered for further use as multi-modal cancer therapy tools

The alluring order in which complex biological networks exist in nature stimulated the interest of chemists to replicate such systems synthetically. With such examples as the deoxyribonucleic acid (DNA) double helix and the phospholipid bilayers, the influence of forces within these networks are solely credited for their excellent stability. The synthetically ordered chemical networks are also held together by interactions within them with little or no external force as seen in the natural systems. This spontaneous and reversible association of molecules or ions to form larger, more complex entities according to the intrinsic information contained in the molecules themselves is known as self-assembly. The self-assembly process is pre-eminent to the formation of ordered structures emerging spontaneously from the precursors in which, the overall structure of the final assemblies is controlled by the symmetry of each of the building blocks. The highly ordered and thermodynamically stable scaffolds are formed via non-covalent interactions including hydrophobic interaction, π-stacking, dipole-dipole interaction, ion-dipole interaction, hydrogen bonding, Van der Waals forces, solvophobic interaction and reversible metal-ligand coordination. These non-covalent interactions are termed as supramolecular interactions. Among several of these self-assembly protocols, the directional metal-ligand coordination strategy has evolved to be a well-established process for the preparation of supramolecular ensembles with pre-defined shapes, cavities and functionalities in a “one-pot” synthesis. Coordination-driven self-assembly strategy is governed by the combination of electron-deficient metal centres and electron-rich organic ligands. The outcome of the final supramolecular architecture is determined by the choice of the pre-designed metal acceptor building blocks as well as the flexibility and steric demands of the ancillary organic ligands. Accurate stoichiometry of each of the building blocks is also a very important factor in coordination-driven self-assembly; although serendipity sometimes happen which is quite unexpected. A large number of these self-assembled supramolecular networks have found useful applications in optoelectronics, material chemistry, adsorption, drug delivery, catalysis, host-guest chemistry, photo- and electro-chemical sensing as well as prospective chemotherapeutics. Transition metals are widely desired as electron-deficient building blocks in supramolecular chemistry. They readily accept lone pair of electrons from electron-rich building blocks. The functional properties of these metals have also been considered during the pre-design of these electron acceptors such that the functional property of each metal can be induced in the final architecture. Pd(II) and Pt(II) metals are highly desirable electron acceptors in supramolecular self-assembly because of their rigid square-planar nature. Nonetheless, Ru(II) and Fe(II) have also been explored as electron acceptors based on their octahedral geometry. Electron-rich building blocks have lone pairs of electrons on their donor sites (nitrogen, oxygen or sulphur) which effortlessly donate electrons to electron-deficient building blocks. The pyridyl appended ligands have been mostly used as the electron-rich building blocks in the construction of supramolecular architectures because of their predictable coordination modes and the symmetrical nature. However, imidazole appended ligands holds a distinctive spot in supramolecular chemistry because of its rotational flexibility and unpredictable binding modes which may lead to uncommon architectures not obtainable with pyridyl appended ligands. Thus, imidazole-based supramolecular architectures are less explored because the outcome of the final architecture cannot be pre-determined during the design. Ruthenium p-cymene complexes have spurred much interest in the last two decades because they possess extremely stable octahedral geometry and has been extensively used in the construction of 2D and 3D supramolecular architectures. The recent search for viable alternatives to platinum drugs in cancer chemotherapy discovered ruthenium as an excellent alternative to platinum because of its low toxicity when compared to platinum. The robustness of the arene head on interaction with biomolecules and the accumulation of large molecular weight compounds specifically in cancer cells rather than in healthy cells also improved the activity of ruthenium supramolecular architectures in cancer therapy. This recent outcome has propelled significant research channelled towards synthesizing better ruthenium-based chemotherapeutics. Additionally, the presence of two different metals in a single self-assembled architecture may also impart an increased activity when compared to the individual activity of each metal. Thus, the heterometallic supramolecular architectures can open a new kind of chemotherapeutics which may give a distinct mechanistic pathway different from those reported in literature. Chapter 1 of this thesis describes the coordination-driven self-assembly strategy with specific emphasis on ruthenium p-cymene self-assembled architectures and their applications. A brief introduction on cancer and cancer therapy is discussed. The use of mononuclear and dinuclear metal-based chemotherapeutics is included while the use of heterometallic complexes as anticancer agents was also highlighted. Chapter 2 showcases the self-assembly of a series of 2D and 3D ruthenium(II) p-cymene architectures constructed from bidentate and tridentate rigid imidazole-based ligands and dinuclear ruthenium(II) building units. The influence of the rotational flexibility of the imidazole ligands on the final architecture was probed. In spite of the likelihood of the formation of different conformational isomeric architectures (syn and anti) and/or polymeric products due to free rotation on the donor sites of the imidazole ligands, the exclusive formation of a single conformational isomer (anti) as the only product turned out to be a noteworthy observation. This indicates that the coordination mode and flexibility of imidazole ligand can control and determine the geometry, topology and conformations of the final molecular architectures. Scheme 1: Self-assembly of 2D macrocycles [2 - 7](OTf)4 employing dinuclear ruthenium(II) building units [1a - 1c](OTf)2 and bidentate rigid imidazole ligands L1 - L2 in methanol at room temperature. Furthermore, the unexpected formation of a tetranuclear cationic macrocycle [8](OTf)4 was reported in the 2 + 3 self-assembly reaction of triazine-based tridentate imidazole ligand L3 and dinuclear ruthenium(II) building unit [1a](OTf)4 over the expected hexanuclear prismatic cage [8a](OTf)6 which is quite surprising. Scheme 2: Schematic representation of the formation of an unexpected tetranuclear macrocycle [8](OTf)4 over the expected hexanuclear prismatic cage [8a](OTf)6. Chapter 3 reports the synthesis of eight octanuclear cages via the coordination-driven self-assembly of two tetradentate pyridyl-based organic ligands and four dinuclear p-cymene Ru(II) acceptor clips. These octanuclear cages were explored in vitro as potential anticancer agents against human lung adenocarcinoma A549 and human cervical cancer HeLa cell lines. Four of the cages with polyaromatic spacers in their Ru(II) acceptor clip unit showed very low micromolar IC50 values and also possess higher anticancer activity than cisplatin against the tested cancer cell lines. The four dinuclear p-cymene Ru(II) acceptor clips A3 in OC-3 and OC-7 revealed some kind of synergy which is evident in their IC50 values against the tested cancer cell lines. In addition, OC-3 and OC-7 trigger both early and late apoptotic phases while OC-4 and OC-8 trigger majorly late apoptotic phase in the cancer cell lines tested. The mechanistic pathway by which cell death is progressing is through the generation of reactive oxygen species (ROS) which is of significant amount in OC-4 and OC-8. Scheme 3: Self-assembly of the discrete octanuclear cages (OC-1 - OC-8) in methanol at room temperature and the schematic illustration of the apoptosis mechanistic pathway. Chapter 4 describes the use of “metalloligands” as electron-rich building blocks and the subsequent use of the metalloligand for “one-pot” self-assembly reactions in the presence of electron-deficient metal acceptor building blocks. The pyridyl donors are the most preferred in metalloligands because of their predictable directionality in self-assembly. The introduction of a second metal into the ligand component of the self-assembled architecture is to bestow additional functionality as well as to construct elegantly designed discrete heterobimetallic supramolecular architectures. Four discrete Ru(II)-Pt(II) hexanuclear trigonal prismatic cages were synthesized employing a tritopic platinum(II) metalloligand and four p-cymene ruthenium(II) clips via coordination-driven self-assembly. The formation of these cages were confirmed by well-known spectroscopic techniques and their structural features was elucidated by geometry optimization. In vitro anticancer studies of these heterometallic cages failed because of solubility challenges in the culture media presumably due to their high molecular weights and many alkyl groups. Scheme 4: Energy minimized structures of the heterometallic trigonal prismatic cages 3a (left) and 3b (right). Hydrogen atoms have been removed for the sake of clarity [Ru: green, Pt: pink, O: red, N: blue, P: orange, C: grey]. Chapter 5 discusses the synthesis of two bidentate platinum(II) metalloligands as well as the self-assembly of six new heterometallic rectangles obtained from four Ru2(OOꓵOO)2(p-cymene)2Cl2 pillars and two bidentate pyridyl-based platinum(II) metalloligands. The Ru4Pt2 and Ru4Pt4 rectangles were structurally characterized and supported by geometry optimisation. Additionally, two Ru4Pt2 and two Ru4Pt4 rectangles were examined for their anticancer properties in eight human cancer cell lines with the aim of checking if the platinum metal centres in the metalloligands can enhance the anticancer activity of the rectangles. The results showed that these heterometallic rectangles are cytotoxic against the cancer cell lines tested but the incorporation of platinum(II) metal(s) into the metalloligand did not further enhance the cytotoxicity in the rectangles tested as hypothesized. The mechanism of cell death is via the generation of reactive oxygen species (ROS) and two Ru4Pt4 rectangles activates both early and late apoptosis. Cell cycle analysis showed that one of the Ru4Pt4 rectangles is a moderate inhibitor of cell cycle progression at the sub G1 phase similar to cisplatin while nuclear condensation and cell blebbing in the cells was also observed in the presence of the two Ru4Pt4 rectangles tested. The overall activity of the heterometallarectangles against the cancer cell lines tested was increased when they exist as a single entity thus reiterating the importance of heterobimetallic supramolecular architectures in cancer therapy. Scheme 5: Schematic diagram of the discrete Ru4Pt4 heterometallic rectangles and illustration of the cell death pathway. The results of the investigation reported in this thesis contribute to the rapidly developing field of organometallic ruthenium(II) self-assembled anticancer chemotherapeutics with specific evidences of the mechanistic pathway of cell death. This results can further guide the design and development of better chemotherapeutics for future use.