Le carcinome hépatocellulaire (CHC) présente des mutations génétiques qui altèrent les principales voies de signalisation, notamment la voie Wnt/β-caténine. En absence de mutation génétique, certains CHC peuvent montrer une activité Wnt exacerbée suite à une inactivation épigénétique d’inhibiteurs ou à une surexpression de ligands Wnts ou de ses récepteurs. De plus, le remodelage de la matrice extracellulaire favorise la progression du CHC. Nous avons montré une association entre l’activation du signal Wnt et le remodelage de la matrice extracellulaire (MEC) dans les cirrhoses et le CHC. Puis modélisé in vitro, les effets des stimuli Wnt extracellulaires sur le phénotype de cellules hépatiques, en absence de mutation de la β-caténine. En effet, les cellules HepaRG ne présentent pas de mutations de la β-caténine, de l’axine et de p53. Ainsi, la stimulation Wnt3a des cellules HepaRG induisait la formation de palissades de cellules fusiformes. De plus, les cellules traitées exprimaient des taux élevés de αSMA, COLIV, c-MYC, CK19 et LGR5 suggérant un phénotype myofibroblastique, en accord avec l’expression des marqueurs de transition épithélio-mésenchymateuse (TEM), SNAIL et TWIST. Ces données sont en faveur du rôle déterminant du microenvironnement Wnt activé dans la progression du CHC entrainant les cellules vers un phénotype progéniteur plus agressif via une TEM. En outre, l'analyse in silico de la signature transcriptomique de l'activation non mutationnelle de la voie Wnt a révélé un réseau de gènes impliqués dans le remodelage de la MEC, la TEM et la différenciation cellulaire. Les résultats suggèrent le rôle de HAPLN1 qui affecterait la migration cellulaire et l'expression des gènes de la MEC. De plus, LGR5 semble favoriser la dédifférenciation des hépatocytes. Au total, 8 gènes marqueurs obtenus in vitro ont été validés in vivo dans une série de 81 CHC humains, par qPCR et immunohistochimie en utilisant des tissus micro-array (78 CHC et 5 foies contrôles). Au total, l'ensemble des données suggère que HAPLN1 a une valeur pronostique sur la récidive et la survie globale du CHC. HAPLN1semble être indépendant du statut mutationnel la β-caténine et des variables cliniques. De plus, sa valeur pronostique est additive avec celle de CK19 + EpCAM et il semble agir en synergie avec NOG. / Hepatocellular carcinoma (HCC) displays signaling pathway disorders, including Wnt/β-catenin. Up-regulation of extracellular Wnt pathway agonists and down-regulation of extracellular Wnt pathway inhibitors result in non-mutational activation of Wnt signaling. In addition, increased extracellular matrix remodeling fosters HCC progression. Thus, we showed that enhanced Wnt signaling is associated with extracellular matrix remodeling in human cirrhosis and cancer. To further investigate non-mutational Wnt pathway activation, we established a model of Wnt activation in HepaRG human HCC progenitor cells carrying wild-type β-catenin, axin and p53. HepaRG progenitor cells treated with Wnt3a became fusiform and grew in palisades with enhanced expression of αSMA, COLIV, CK19, c-MYC, LGR5, SNAIL and TWIST, suggesting that enhanced extracellular Wnt signaling may drive HCC cells toward a more aggressive progenitor and epithelial mesenchymal transition (EMT) phenotype. Moreover, in silico analysis of the transcriptomic signature of non-mutational Wnt activation revealed a gene network involved in ECM remodeling, EMT and cell fate. Results suggest a role of HAPLN1, affecting extracellular matrix gene expression and cell migration and of LGR5 in hepatocyte dedifferentiation. Eight genes among the HepaRG gene expression dataset were validated in vivo in a collection of 81 human HCC samples and controls by qPCR and immunohistochemistry using tissue micro-arrays (78 HCC samples and 5 normal livers) in the light of β-catenin activation and mutational status. In conclusion, data suggest that HAPLN1 has a prognostic value on overall survival and recurrence of HCC. HAPLN1 appears to be independent of clinical features and β-catenin mutationnal status. Moreover, HAPLN1 appears to have an additive prognostic value with CK19 + EpCAM and act synergistically with NOG.

L’adénocarcinome pancréatique (PDA) présente une résistance accrue aux chimiothérapies. Un concept propose que sa composition cellulaire participe à ce processus en limitant l’accès aux drogues tout en modulant les capacités des cellules tumorales. En effet, les cellules non tumorales, principalement mésenchymateuses (CAFs) et immunitaires, représentent 70% de la masse tumorale et forment le microenvironnement intra-tumoral ou stroma. L’impact du stroma dans le développement et la progression des PDA se trouve être au centre d’un large champ d’investigations cliniques. Notre première étude a porté sur un facteur neurotrophique, Slit2, impliqué dans la guidance axonale est sécrété par les CAFs. Ce dernier induit une augmentation de la migration des cellules de Schwann et des changements morphologiques et quantitatifs des cellules neuronales. Ainsi, les nerfs se retrouvent plus nombreux et de taille plus importante dans la tumeur comparée à un pancréas sain, c’est ce qu’on appelle le remodelage neural. Notre second travail a permis d’identifier un complexe multi-protéique (ANXA6/LRP1/TSP1), associé au trafic vésiculaire, présent uniquement dans le compartiment stromal et plus particulièrement dans les CAFs. Ce complexe est porté par des vésicules extracellulaires et procure un avantage prolifératif et pro-migratoire aux cellules tumorales. Les données obtenues au cours de mon travail de thèse constituent un rationnel fort pour étudier le potentiel thérapeutique des éléments permettant le dialogue entre les différents compartiments de la tumeur dans le but de sensibiliser les cellules tumorales aux chimiothérapies et ainsi d’améliorer la survie des patients. / Pancreatic adenocarcinoma (PDA) is particularly resistant to current therapies. A concept suggests that its cellular composition participates in this process, limiting drugs access and affecting tumor cells behavior. Indeed, non-tumor cells, mainly mesenchymal (including Cancer Associated Fibroblasts, CAFs) and immune cells display over 70% of the tumor mass and form the intra-tumoral microenvironment or stroma. The impact of stroma in PDA development and progression is at the center of many clinical investigations. Firstly, we studied a neurogenic factor, Slit2, implicated in axon guidance pathway and secreted by CAFs. Slit2 increases Schawnn cells migration and morphologic changes of neural cells. Indeed, nerve size and density are increased in a tumor compared to a healthy pancreas, that is called, neural remodeling. Secondly, we worked on a multi-proteic complex (ANXA6/LRP1/TSP1), associated to vesicular trafficking, only expressed in stromal compartment, and mainly in CAFs. This complex is present in extracellular vesicles and confers proliferative and pro-migratory capacities to tumor cells. Data obtained during my thesis constitute an important rationale to target the crosstalk between tumor and stromal compartment, in order to sensitize tumor cells to chemotherapy and improve patient survival.

The aim of this thesis is to design a strategy for Vodafone Czech Republic, a.s. Using the open data an analysis of macroenvironment as well as microenvironment are performed, where a definition and a breakdown of telecommunication market into five segment is made. Following is the analysis of Porter five forces, which analyses competition forces on the market as well as to the Vodafone. Further on a financial analysis and product portfolio analysis is made, which serves as the basis of Ansoff matrix. In the conclusion a synthesis of the analyses is made and several strategies are designed.

Il existe une littérature abondante sur les mécanismes cellulaires de résistance à la chimiothérapie, décrivant notamment les pompes d’efflux, les modifications des cibles (comme les topoisomérases) ou les altérations de l’apoptose. Peu de publications s’intéressent aux mécanismes de chimiorésistance liée au microenvironnement tumoral. Les agents anticancéreux doivent traverser l’interstitium tumoral pour atteindre toutes les cellules (dont les cellules hypoxiques éloignées des vaisseaux sanguins) à des concentrations suffisantes pour être létales. Les modèles de culture cellulaire en couches multiples ont permis de montrer la faible pénétration des molécules de chimiothérapie. Les techniques d’immunohistochimie permettent une mesure quantitative de la distribution de ces molécules à partir des vaisseaux sanguins. Nous avons évalué la pénétration de plusieurs inhibiteurs de topoisomérases : topotécan, doxorubicine, mitoxantrone et banoxantrone. Nous avons comparé la distribution de ces molécules à travers des tissus sains et des tissus tumoraux, démontrant la pénétration limitée des molécules de chimiothérapie dans les tumeurs. Par contre, nous avons montré que la banoxantrone pénètre rapidement et de façon uniforme. Cette pro-drogue est convertit en AQ4 (un inhibiteur de topoisomérase II ressemblant à la mitoxantrone) en condition d’hypoxie. La mitoxantrone cible les cellules bien oxygénées et AQ4 cible les cellules hypoxiques. Cette combinaison de traitement aboutit à une distribution intratumorale complémentaire et à une amélioration de l’activité antitumorale. Ainsi, optimiser la pénétration des chimiothérapies et/ou cibler spécifiquement les cellules hypoxiques peut contourner la chimiorésistance liée au microenvironnement tumoral. / There is a vast literature about mechanisms that lead to drug resistance of individual cancer cells, including drug export pumps, changes in expression of targets (such as topoisomerases) or alterations in apoptosis. A smaller number of publications has drawn attention to causes of drug resistance that depend on the solid tumour microenvironment. Drugs must penetrate the extra-vascular space to reach all of the cancer cells (including cells far from blood vessels in hypoxic condition) in sufficient concentration to cause lethal toxicity. Model systems such as multilayered cell cultures provide direct evidence of poor drug penetration through tumour tissue. In vivo techniques using quantitative immunohistochemistry allow studying drug distribution as a function of distance from the nearest blood vessel. We have evaluated the penetration of several topoisomerase inhibitors: topotecan, doxorubicine, mitoxantrone and banoxantrone (AQ4N). We have compared the distribution of these drugs through normal and tumour tissue, demonstrating the limited perivascular distribution of conventional chemotherapies in tumour. We have also showed the rapid and uniform penetration of banoxantrone. This pro-drug is reduced to AQ4 (a topoisomérase II inhibitor of similar structure to mitoxantrone) under hypoxic condition. The targeting of mitoxantrone to oxygenated regions and AQ4 to hypoxic tumour regions resulted in effective drug exposure over the entire tumour and increased tumour growth delay compared with either drug alone. Improving drug penetration and/or targeting hypoxic tumour cells may overcome chemoresistance due to the tumour microenvironment.

O transplante de células-tronco hematopoéticas (CTHs) é o tipo mais bem-sucedido de terapia celular realizado até os dias atuais. No entanto, apesar do sucesso e da relevância clínica das CTHs isoladas a partir de fontes adultas, o uso destas células tem algumas limitações em relação à sua disponibilidade, compatibilidade imunológica e risco de contaminação. Desse modo, busca-se o desenvolvimento de soluções para as dificuldades apontadas para suprir a demanda de transplantes. Uma abordagem emergente para superar este problema é baseada na cultura e diferenciação de células-tronco embrionárias humanas (CTEhs). Estas são célulastronco pluripotentes e indiferenciadas com elevada capacidade de auto-renovação e diferenciação em todas as células derivadas dos três folhetos germinativos. No entanto, os métodos de diferenciação utilizados para a produção de CTHs a partir de células pluripotentes ainda não são eficientes. Os protocolos descritos até o momento têm gerado números variados e populações de células heterogêneas, e produz apenas CTHs muito primitivas e imaturas com baixa capacidade funcional in vivo. Parte desta dificuldade pode decorrer da ineficiência do microambiente de cultura para a diferenciação. Neste trabalho, nós demonstramos um eficiente protocolo de diferenciação hematopoética baseado em cocultivo de CTEhs com fibroblastos embrionários murinos com alto rendimento na geração de célulastronco/progenitoras hematopoéticas (CTPHs) que expressam os antígenos CD45, CD43, CD31 e CD34, e apresentam potencial clonogênico in vitro equivalente ao de células mononucleares isoladas de sangue de cordão umbilical. Nós fomos capazes de produzir todas as células das linhagens eritróide e mielóide em diferentes estágios de maturação, como também células positivas para marcadores linfóides. Demonstramos ainda que as células hematopoéticas surgem no sistema de cultura a partir de um endotélio-hemogênico constituído por células CD34+CD31+. No entanto, apesar das características maduras das CTPHs obtidas por tal método, os ensaios de reconstituição hematopoiética mostraram que estas células ainda possuem limitada capacidade funcional de enxertamento em camundongos imunocomprometidos quando transplantadas por via retro-orbital. / Hematopoietic stem cells (HSC) transplant is the most successful type of cell therapy carried out to date. However, despite the success and the clinical relevance of HSC isolated from adult sources, these cells have some limitations regarding its availability, immunological compatibility and risk of contamination. Thus, we seek to develop solutions to overcome these difficulties to supply the demand for transplants. An emerging approach to overcome this problem is based on human embryonic stem cells (hESCs) culture and differentiation. These are pluripotent and undifferentiated stem cells with high capacity for self-renewal and differentiation in all cells derived from the three embryonic germ layers. However, differentiation methods used for HSC production from pluripotent cells are not efficient yet. Protocols described so far have generated varying numbers and heterogeneous cell populations, and produce only very primitive and immature HSC with low in vivo functional capacity. Part of this difficulty may result from the inefficiency of the microenvironment of culture for differentiation. Here, we demonstrate an efficient protocol based on co-culture of hESCs with mouse embryonic fibroblasts for hematopoietic differentiation with high performance to generate in vitro hematopoietic stem/progenitor cells (HSPCs) that express CD45, CD43, CD31 and CD34 antigens with high purity of positive cells. We were able to produce all cells of erythroid and myeloid lineages at different stages of maturation. Lymphoid potential of hematopoietic cells was also evidenced. We demonstrated the primitive origin of hematopoietic cells through capillary-like structures constituted by hemogenic CD34+CD31+ cells. However, despite mature features of HSPCs obtained by our protocol, hematopoietic reconstitution assays showed that these cells have yet limited functional capacity for grafting into immunocompromised mice when exogenously transplanted by retro-orbital route.

Le micro-environnement tumoral joue un rôle dans la croissance, l'invasion tumorale et la résistance aux traitements. Il est essentiel de comprendre les mécanismes qui régulent la communication entre les cellules tumorales et ce micro-environnement pour développer des thérapies efficaces. Dans ce contexte, les protéases extracellulaires de la famille des Adamalysines sont des acteurs importants dans la progression tumorale en agissant sur le remodelage de la matrice extracellulaire (MEC) et la biodisponibilité des médiateurs de communication cellulaire tels que les cytokines, les chimiokines et les facteurs de croissance. Mes travaux ont mis en évidence une nouvelle interaction entre ADAM12, un marqueur mésenchymateux induit au cours de la transition épithélio-mésenchymateuse (EMT) dépendante du TGF-β et ZO-1, une protéine d’échafaudage exprimée dans des jonctions serrées de cellules épithéliales. Ces deux protéines sont redistribuées, dans des structures de type invadopodes pour promouvoir la dégradation de la MEC. Nous avons par ailleurs réalisé un criblage in silico qui nous a permis d’identifier un cluster d’adamalysines dont les gènes sont co-exprimés chez des patients atteints d’un carcinome hépatocellulaire. Parmi ces adamalysines, nous avons mis en évidence la protéine ADAMTS12, qui joue un rôle clé dans le développement de la fibrose hépatique en lien avec une réponse inflammatoire aigüe ou chronique. / Tumor microenvironment plays a major role in tumor growth, invasion and resistance to treatments. Understanding the mechanisms that regulate communication between tumor cells and their microenvironment is essential to develop effective therapies. In this context, Adamalysin extracellular proteases play major role in tumor progression, by modulating the extracellular matrix (ECM) remodeling and the bioavailability of cell communication mediators such as cytokines, chemokines and growth factors. My work revealed a new interaction between ADAM12, a mesenchymal marker induced during the epithelial-mesenchymal transition (EMT) dependent on TGF-β and ZO-1, a scaffolding protein expressed in tight junctions of epithelial cells. Both proteins are redistributed in invadopodia-like structures to promote ECM degradation. In a second study, we carried out an in silico screening that allowed us to identify a cluster of Adamalysin genes co-expressed in patients with hepatocellular carcinoma. Among these Adamalysins we have studied the protein ADAMTS12 in more details, and shown that this protein plays a key role in the development of liver fibrosis involving an acute or chronic inflammatory response.

TRAIL ligand can trigger apoptosis of permissive human cells via engagement of its two pro- apoptotic receptors TRAIL-R1 (DR4) and TRAIL-R2 (DR5). Its ability to induce apoptosis independently on p53 status and to selectively kill cancer cells in vitro and in vivo made this ligand an attractive target in cancer research. However, acquired resistance of primary cancer cells, unsatisfactory outcome of clinical trials and recent studies arguing that TRAIL might under specific conditions promote cancer progression, opened new plethora of questions, which need to be addressed. Though both receptors DR4 and DR5 are ubiquitously expressed, different types of tumours show preference for either of the receptors. The relative participation of DR4 and DR5 in TRAIL- induced signalling is still largely unknown. To analyse TRAIL receptor-specific signalling, I prepared Strep-tagged, trimerised variants of recombinant human TRAIL ligands with high affinity for either DR4 or DR5 receptor. Using these receptor-specific ligands, I examined a contribution of individual pro-apoptotic receptors to TRAIL-induced signalling pathways. I found that in TRAIL resistant colorectal HT-29 cells but not in pancreatic PANC-1 cancer cells, DISC formation and initial caspase-8 processing proceeded comparably in both DR4- and...

Indiana University-Purdue University Indianapolis (IUPUI) / Background: Cancer is the leading cause of death worldwide and as a result is one of the most studied topics in public health. Breast cancer and prostate cancer are the most common cancers among women and men respectively. Gene expression and image features are independently prognostic of patient survival. However, it is sometimes difficult to discern how the molecular profile, e.g., gene expression, of given cells relate to their spatial layout, i.e., topology, in the tumor microenvironment (TME). However, with the advent of spatial transcriptomics (ST) and integrative bioinformatics analysis techniques, we are now able to better understand the TME of common cancers. Method: In this paper, we aim to determine the genes that are correlated with image topology features (ITFs) in common cancers which we denote topology associated genes (TAGs). To achieve this objective, we generate the correlation coefficient between genes and image features after identifying the optimal number of clusters for each of them. Applying this correlation matrix to heatmap using R package pheatmap to visualize the correlation between the two sets. The objective of this study is to identify common themes for the genes correlated with ITFs and we can pursue this using functional enrichment analysis. Moreover, we also find the similarity between gene clusters and some image features clusters using the ranking of correlation coefficient in order to identify, compare and contrast the TAGs across breast and prostate cancer ST slides. Result: The analysis shows that there are groups of gene ontology terms that are common within breast cancer, prostate cancer, and across both cancers. Notably, extracellular matrix (ECM) related terms appeared regularly in all ST slides. Conclusion: We identified TAGs in every ST slide regardless of cancer type. These TAGs were enriched for ontology terms that add context to the ITFs generated from ST cancer slides.

Cancer development and progression vary depending on tumor type, localization, invasion, immunogenicity and the ability of immune system to become activated. There are frequent interactions between tumor cells and immune cells, occuring locally at the site of primary tumor or distally through paracrine signalling of various mediators and cytokines. The main subject of this PhD thesis is to study key factors and aspects of immune response in cancer patients. In the first part, we analyzed immune cells infiltrating tumor tissues of ovarian cancer patients at different stages of disease. We focused on the dynamics of immune response, primarily on frequency of individual T lymphocyte populations in peripheral blood and tumor infiltrating T lymphocytes in tumors of early and advanced stages of ovarian cancer. We found that during disease progression there is a gradual decrease of proinflammatory Th17 and Th1 immune responses and a specific recruitment of regulatory T cells to the tumor site, which results in a significant immune suppression in the tumor microenvironment. In the second part, we demonstrated that the character of immune response in HPV-positive head and neck cancer patients is very different from the patients with tumors not associated with HPV infection. In HPV-positive patients, significantly...

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