Drug combination therapies for cancer treatment show high efficacy but often induce severe side effects, resulting in dose or cycle number reduction. We investigated the impact of neoadjuvant chemotherapy (neoCTx) adaptions on treatment outcome in 59 patients with pancreatic ductal adenocarcinoma (PDAC). Resections with tumor-free margins were significantly more frequent when full-dose neoCTx was applied. We determined if patient-derived organoids (PDOs) can be used to personalize poly-chemotherapy regimens by pharmacotyping of treatment-naïve and post-neoCTx PDAC PDOs. Five out of ten CTx-naïve PDO lines exhibited a differential response to either the FOLFIRINOX or the Gem/Pac regimen. NeoCTx PDOs showed a poor response to the neoadjuvant regimen that had been administered to the respective patient in 30% of cases. No significant difference in PDO response was noted when comparing modified treatments in which the least effective single drug was removed from the complete regimen.Drug testing of CTx-naïve PDAC PDOs and neoCTx PDOs may be useful to guide neoadjuvant and adjuvant regimen selection, respectively. Personalizing poly-chemotherapy regimens by omitting substances with low efficacy could potentially result in less severe side effects, thereby increasing the fraction of patients receiving a full course of neoadjuvant treatment.

Background Treatment of cancer patients in certified cancer centers, that meet specific quality standards in term of structures and procedures of medical care, is a national treatment goal in Germany. However, convincing evidence that treatment in certified cancer centers is associated with better outcomes in patients with pancreatic cancer is still missing. Methods We used patient-specific information (demographic characteristics, diagnoses, treatments) from German statutory health insurance data covering the period 2009–2017 and hospital characteristics from the German Standardized Quality Reports. We investigated differences in survival between patients treated in hospitals with and without pancreatic cancer center certification by the German Cancer Society (GCS) using the Kaplan–Meier estimator and Cox regression with shared frailty. Results The final sample included 45,318 patients with pancreatic cancer treated in 1,051 hospitals (96 GCS-certified, 955 not GCS-certified). 5,426 (12.0%) of the patients were treated in GCS-certified pancreatic cancer centers. Patients treated in certified and non-certified hospitals had similar distributions of age, sex, and comorbidities. Median survival was 8.0 months in GCS-certified pancreatic cancer centers and 4.4 months in non-certified hospitals. Cox regression adjusting for multiple patient and hospital characteristics yielded a significantly lower hazard of long-term, all-cause mortality in patients treated in GCS-certified pancreatic centers (Hazard ratio = 0.89; 95%-CI = 0.85–0.93). This result remained robust in multiple sensitivity analyses, including stratified estimations for subgroups of patients and hospitals. Conclusion This robust observational evidence suggests that patients with pancreatic cancer benefit from treatment in a certified cancer center in terms of survival. Therefore, the certification of hospitals appears to be a powerful strategy to improve patient outcomes in pancreatic cancer care.

Le cancer du pancréas est l’un des plus chimiorésistants, avec un taux de survie sur 5 ans inférieur à 5%. La chimiorésistance pourrait être due à la présence de cellules initiatrices de tumeur (TICs), une petite sous-population des cellules tumorales possédant la capacité de régénérer une nouvelle tumeur. Il a été démontré que la metformine cible les TICs par un mécanisme non élucidé. Il est connu que la metformine affecte le métabolisme du carbone. Il a également été démontré que le métabolisme du carbone, plus précisément la glycine décarboxylase (GLDC), est à la fois nécessaire et suffisant à l’acquisition de propriétés d’initiation tumorale. Nous proposons que la metformine cible les cellules initiatrices de tumeur en affectant le métabolisme du carbone. Nous avons utilisé des lignées cellulaires dérivées d’un modèle murin de cancer du pancréas pour comparer l’expression génique de lésions bénignes versus malignes. Les cellules malignes surexpriment Gldc. La metformine diminue l’expression de Gldc, et la surexpression de Gldc diminue la sensibilité à la metformine dans un essai de sphères tumorales. La metformine induit une augmentation du ratio NADP+/NADPH, et la surexpression de Gldc empêche cette augmentation. Nous proposons que la metformine diminue l’expression de Gldc, ce qui cause une diminution du flux du métabolisme du carbone, et donc une diminution de la production de NADPH par ce dernier. L’augmentation du ratio NADP+/NADPH inhibe la synthèse des acides gras et la régénération de la glutathione, ce qui pourrait expliquer la diminution de la formation de sphères tumorales sous traitement metformine. / Pancreatic cancer is one of the most chemoresistant cancers, with a 5-year survival rate lesser than 5%. Chemoresistance might be due to the presence of tumor-initiating cells (TICs), a small subpopulation of tumor cells with stem-like characteristics which possess the unique ability to self-renew and to generate a new tumor. Metformin has been shown to affect TICs in various cancer types, but the mechanism through which it does so is unclear. It is known that metformin affects one-carbon metabolism. It has also been shown that one-carbon metabolism, more precisely the glycine decarboxylase (GLDC) enzyme, is both necessary and sufficient to the acquisition of tumor-initiating properties. Considering this, we propose that metformin affects TICs by targeting one-carbon metabolism. Using cell lines derived from a genetically engineered mouse model of pancreatic cancer, we compared gene expression data from cells derived from benign pancreatic neoplasia with cells derived from pancreatic ductal adenocarcinoma (PDAC), and found that PDAC cells exhibited a dramatic increase in Gldc expression. Metformin treatment decreases Gldc expression in PDAC cell lines, and Gldc overexpression greatly decreases metformin sensitivity in a tumor sphere assay. Metformin induces an increase in NADP+/NADPH ratio, which is rescued by Gldc overexpression. We propose a model in which metformin decreases Gldc expression, which causes reduced flux through mitochondrial one-carbon metabolism. This results in decreased NADPH production by this pathway. This increase in NADP+/NADPH ratio impairs fatty acid biosynthesis and glutathione regeneration. Together these effects might explain the decrease of tumor sphere formation under metformin treatment.

Pancreatic cancer (PC) is extremely severe malignant disease with a five-year survival of less than 5%. Currently there is no reliable tool for the diagnosis of PC in its early stages. At the time of clinical symptoms most patients are in an advanced stage of the disease and the treatment does not usually have a significant effect. For these reasons emphasis is gradually shifting to the search for the suitable molecular markers for improvement of the diagnosis and assessment of the survival prognosis with respect to a possibility of surgical treatment. MiRNA represent one of the most promising markers, although, their examination in pancreatic tissue is a complicated process. One of the reasons is the very small amount of the source material coming from a fine needle biopsy. A second cause of problems is the subtle character of the pancreatic tissue resulting in significantly lower yields of molecular genetic analysis when compared to other epithelial tissues. An additional negative factor is heterogeneity of the tissue resulting in disproportionate representation of tumor cells within the sample. A suitable choice of procedures for isolation of nucleic acids (NA) and subsequent analysis including quantification of tumor cells is critical for accurate evaluation of the miRNA levels. This work is...

Thermoablationsverfahren werden in der klinischen Routine zur Therapie bei Patienten mit primären Lebertumoren und Lebermetastasen eingesetzt, bei denen von einer Operation abgesehen wird. Die laserinduzierte Thermotherapie (LITT) ist ein minimal invasives radiologisches Verfahren zur perkutanen Tumorablation. Mit der Magnetresonanztomographie (MRT) am Hochfeldtomographen (1.5 Tesla) steht eine radiologische Methode mit der Option einer präzisen Prozesskontrolle der Thermoablation und einer suffizienten Erfolgskontrolle zur Verfügung. Ziel dieser Arbeit war es, im Tierexperiment die Anwendung der LITT zur Ablation von Pankreasgewebe zu erproben, das Potenzial der MRT für die Prozesskontrolle der LITT am Pankreas zu bestimmen und neue MRT-Sequenzen mit neuen Kontrastmitteln für die Optimierung der Erfolgskontrolle zu erforschen. Die LITT am Pankreas im Rahmen einer Pilotstudie an 15 Läuferschweinen war perkutan komplikationsarm durchführbar, generalisierte Pankreatitiden oder Blutungen traten nicht auf. Die qualitative Prozessbeobachtung mittels thermosensitiver Sequenzen zeigte eine hohe Übereinstimmung zwischen magnetresonanztomographisch dokumentierten Thermoeffekten und histopathologisch verifizierten thermisch induzierten Nekrosen. Die Untersuchung und invasive Kalibrierung verschiedener Messmethoden in vivo zur quantitativen MRT-Thermometrie ergab Vorteile für den Einsatz der Protonenresonanzfrequenz-Methode. Zur Optimierung der Erfolgskontrolle nach LITT von Lebergewebe im Tierexperiment sowie klinisch bei Lebermetastasen wurden die MRT-Kontrastmittel Gadomesoporphyrin, Eisenoxid und Gadobutrol erprobt. Mittels Spätaufnahmen 6 - 18 h post injectionem wurden mit Gadobutrol thermisch induzierte Nekrosen präzise visualisiert. / Thermoablation of primary liver tumors and liver metastases is widely used in patients without surgical options. The laser-induced thermotherapy (LITT) is a minimal invasive radiologic procedure for percutaneous tumor ablation. With high field magnetic resonance imaging at 1.5, monitoring of thermoablation and visualization of thermal induced ablation zones can be performed precisely. Aim of this work was to investigate the feasibility of MR-guided LITT of pancreatic tissue and to optimise the contrast between thermal induced lesions, residual tumor and normal tissue after LITT procedure. MR-guided LITT was feasible in 15 female pigs, generalized pancreatitis or bleeding did not occur. MR monitoring by thermosensitive sequences precisely visualized thermal induced ablation zones verified by histopathologic examination. Best results of MR thermometry (thermo-mapping) were obtained by proton resonance frequency method. Gadolinum- mesoporphyrine, superparamagnetic iron oxides (SPIO) and gadobutrol were used to optimise ablation control. Late enhanced imaging 6 - 18 hours after injection of gadobutrol precisely visualized thermal induced necrosis. In conclusion, percutaneous MR guided LITT of pancreatic tissue of female pigs was feasible and monitoring of thermoablation could be performed accurately. In contrast to other imaging methods, MR using new contrast agents enables accurate visualization of thermal induced necrosis.

A atividade de cisteíno proteases (CP) tem sido relacionada a diferentes patologias, como no caso da leishmaniose, doença de Chagas de alguns tipos de câncer. Devido a homologia entre as cisteíno proteases presentes em altos níveis nesses sistemas celulares, foi investigada aqui a importância dessas enzimas para o desenvolvimento e estabelecimento dessas doenças a partir da atividade biológica in vitro de novos inibidores reversíveis de cisteíno proteases. De maneira geral, as substâncias apresentaram relevante atividade inibitória de cisteíno proteases expressas pelos diferentes sistemas celulares, com máximo de inibição de 42% para o Neq0554 em relação à atividade de CP expressas por Leishmania spp. e 76% em relação a atividade de CP expressas por células de câncer de pâncreas. Diferentes níveis de atividade biológica foram observados entre os sistemas celulares, porém todos apresentaram supressão em relação aos parâmetros citostáticos após a inibição da atividade de CP. Quando testados em Leishmania spp. o crescimento celular foi suprimido em pelo menos 67%, com máximo de inibição de 95% para o Neq0551 a 10 μM. Da mesma maneira, em células de câncer de pâncreas, alterações no ciclo celular e supressão dos processos de migração e formação de colônias foram os resultados mais evidentes, comretenção de 50% da capacidade de formação de colônias das células Mia-Paca2 pelo Neq0554 a 10 μM. Já em relação aos protozoários da capa Y de Trypanosoma cruzi os inibidores testados apresentaram interessante seletividade contra os parasitos, em relação à célula hospedeira LLC-MK2, além de promoverem a supressão de cerca de 80% do processo de invasão celular in vitro quando a célula hospedeira foi previamente tratada com 10 μM do inibidor Neq0662 por 2 h antes do processo de infecção. Por fim, a encapsulação do Neq0554 em apoferritina promoveu um incremento na atividade anticancerígena para células de câncer de pâncreas, com IC50 de 79 μM contra > 200 μM em relação às células de fibroblasto, aumentando sua seletividade. De maneira geral, os resultados corroboram a hipótese de a inibição de cisteíno proteases nos sistemas celulares é eficiente para promover efeitos citostáticos, podendo ser utilizada com controle e supressão do desenvolvimento das patologias. Além disso, a atividade de CP nas células de protozoários e câncer de pâncreas apresentou perfil semelhante de ação, no qual inibidores de CP não promoveram a morte em nível significativo das células, mas ressaltaram os efeitos citostáticos em relação ao crescimento celular. / Cysteine proteases (CP) activity has been related to different pathologies, such as leishmaniasis, Chagas disease and some types of cancer. Due to the homology between cysteine proteases expressed by these cellular systems, it was investigated here the importance of these enzymes for the development and establishment of these diseases based on the in vitro biological activity of novel reversible cysteine protease inhibitors. In general, the inhibitor showed a significant inhibitory activity of cysteine proteases expressed by the different cellular systems, with a maximum inhibition of 42% for Neq0554 concerning the CP activity expressed by Leishmania spp. and 76% to CP activity expressed by pancreatic cancer cells. Different profiles of biological activity were observed between the cellular systems, but all substances had significant CP activity suppression, in cytostatic levels after the inhibition of CPA. When the inhibitors were tested against Leishmania spp., the cell growth was suppressed by at least 67%, with maximum inhibition of 95% for Neq0551 at 10 μM. Similarly in pancreatic cancer cells, changes in the cell cycle profile were the most evident results, as well as the suppression of migration and colony formation ability, with 50% retention of the colony development of Mia-Paca2 cells by Neq0554 at 10 μM. In contrast, to protozoa from Trypanosoma cruzi Y strain, the inhibitors tested showed an interesting selectivity against the parasites concerning the host cell LLC-MK2, also promoting the in vitro cell invasion suppression in about 80% when the host cell was pre-treated with Neq0662 10 μM for 2 h. Finally, the encapsulation of Neq0554 promoted an increase in its anticancer activity against pancreatic cancer cells, with IC50 of 79 μM alongside > 200 μM to fibroblast cells, besides increasing its selectivity. In general, the results corroborate the hypothesis that the inhibition of cysteine proteases in the cellular systems is efficient to promote cytostatic effects, being an interesting tool to be used as control and development suppression of some pathologies. Also, CP activity in protozoa cells and pancreatic cancer showed a similar profile of action, in which cysteine protease inhibitors did not promote death at a significant level for the cells, but emphasized cytostatic effects about cell growth.

Ce travail avait deux objectifs: 1) définir des groupes de patients (pts) susceptibles de bénéficier d’un conseil génétique par l’identification de facteurs prédictifs de l’existence d’une mutation du gène CDKN2A, un des gènes majeurs de prédisposition au mélanome, dans les familles ne comportant que deux cas (Fam_2 cas). 2) la caractérisation épidémiologique et clinique d’entités particulières du mélanome dans l’objectif secondaire de contribuer à l’identification de gènes de prédisposition à ces entités. Les 2 entités étudiées étaient le mélanome cutané (MC) associé au cancer du rein (CR) et les mélanomes muqueux de la sphère ano-génitale (MMAG).Les populations d’étude sont une collection de 293 pts atteints de MC recrutés de façon consécutive sans connaissance à priori de l'histoire familiale et la collection française MELARISK qui comprend ≥ 3000 sujets prélevés appartenant à des familles à cas multiples de mélanomes ou ayant un MC survenant dans un contexte particulier (association à un autre cancer, topographie rare, survenue avant l’âge de 20 ans, MC multiples sporadiques). Nous avons étudié l'effet de 3 facteurs prédictifs potentiels sur la présence d’une mutation de CDKN2A dans une famille en fonction du nombre de pts atteints dans une famille (2 pts versus ≥3 pts). L’étude a été menée dans 483 familles françaises comprenant 387 Fam_2 cas, et 96 familles avec ≥3 pts atteints de mélanome (Fam_3+ cas). Les facteurs étudiés dans la famille un à un puis conjointement étaient : l’âge médian <50 ans au diagnostic de MC, la survenue de ≥1 cas de MC primitifs multiples (MPM) et la survenue de ≥1 cas de cancer du pancréas (CPCP). La fréquence des mutations était plus élevée dans les Fam_3+ cas (32%) que dans les Fam_2 cas (13%). Alors qu’un âge jeune au diagnostic et la survenue de ≥ 1 MPM étaient associés à la présence de mutations de CDKN2A dans les Fam_2 cas, un âge jeune au diagnostic ainsi que la présence de ≥1 cas de CP était associé significativement aux mutations de CDKN2A dans les Fam_3+ cas. L’étude a montré que les caractéristiques cliniques associées aux mutations de CDKN2A varient, en France, pays de faible incidence de mélanome, en fonction du degré d’agrégation familiale. L’identification de facteurs prédictifs de mutations de CDKN2A dans les Fam_2 cas a contribué à définir des sous-groupes de familles (âge jeune au diagnostic, survenue de MPM) dans lesquels la fréquence des mutations de CDKN2A est supérieure à 20% et auxquels il est légitime de proposer un test génétique. L’analyse des deux séries de pts MM+CR et MMAG a permis d’identifier, en les comparant à la série de MC recrutés de manière consécutive, leurs caractéristiques cliniques et histologiques. Dans ces deux séries, nos résultats ont mis en évidence un contexte de prédisposition héréditaire en partie indépendant de CDKN2A. L’étude de l’association MC et CR chez un même patient a eu deux conséquences pratiques: pour les cliniciens ces résultats suggèrent l’intérêt d’un examen dermatologique en cas de CR et l’intérêt de l’échographie abdominale dans le bilan initial d’un MC pour le dépistage du CR; pour la recherche en génétique, cette série a contribué à l’identification d’une mutation germinale dans le gène MITF qui augmente le risque de développer un MC, un CR ou l’association des deux cancers et qui a des propriétés biologiques intéressantes. L’étude des MMAG a montré que ces mélanomes pouvaient être associés à des MC chez un même malade et/ou survenir dans un contexte familial de mélanome. Le corollaire clinique de ces résultats est que l’examen dermatologique de dépistage ou de surveillance doit être à la fois cutané et muqueux dans un contexte familial de mélanome et qu’en cas de MMAG un examen dermatologique des apparentés doit être proposé comme c’est la règle dans les MC. L’absence de mutation de CDKN2A dans ces localisations muqueuses incite à entreprendre des études génétiques pour identifier les gènes impliqués. / This thesis had two main objectives: 1) To define groups of patients which may benefit from genetic counseling by identifying predictors of mutations of the CDKN2A gene, a major gene predisposing to cutaneous melanoma (CM) in families with only two cases. 2) Epidemiological and clinical characterization of specific entities of melanoma with the secondary objective of contributing to the identification of susceptibility genes for these entities. Coexistence of CM with renal cell carcinoma and mucosal anogenital melanomas were studied.The study populations are a collection of 293 melanoma patients that were ascertained systematically and the French collection MELARISK which is a collection including over 3000 subjects drawn from families with multiple cases of melanoma or melanoma occurring in a particular context (association with another cancer, rare locations, occurrence before the age of 20, multiple sporadic melanomas).We investigated association of three clinical features with the presence of a CDKN2A mutation in a family by extent of CM family clustering (2 versus ≥3 CM patients among first-degree relatives in a family).The study was conducted in 483 French families including 387 families with two melanoma patients, and 96 families with three or more patients with melanoma. The factors examined individually and in a joint analysis in a family were: median age at diagnosis <50 years, ≥1 patient in a family with multiple primary melanomas (MPM) or with pancreatic cancer. The frequency of CDKN2A mutations was higher in F3+ families (32%) than in F2 families (13%). While early age at melanoma diagnosis and occurrence of MPM in ≥1 patient were significantly associated with the risk of a CDKN2A mutation in F2 families, early age at melanoma diagnosis and occurrence of pancreatic cancer in a family were significantly associated with CDKN2A mutations in F3+ families. Thus this study showed that clinical features associated with CDKN2A mutations vary, in France, a country of low incidence of melanoma, according to the degree of familial clustering. Identifying predictors of CDKN2A mutations in families with two melanoma cases has helped to define subgroups of families (early age at CM diagnosis, and/or ≥1 MPM patient) in which the frequency of CDKN2A mutations is above 20% such that these subgroups of F2 families should be offered genetic testing.The analysis of two series of patients, either patients with melanoma coexisting with renal cell carcinoma or patients with anogenital mucosal melanoma identified their clinical and histological features by comparing them to a series of melanomas that were ascertained systematically. In both series, our results suggested a genetic predisposition at least partly independent of CDKN2A. The study of the c renal cell carcinoma; coexistence of CM and renal cancer in the same patient had two practical consequences for clinicians: it suggests the interest of a dermatologic screening visit in patients with renal cell carcinoma and that abdominal ultrasonography or computed tomography scanning performed at the initial workup and during the follow-up of patients with CM may be of value for the early detection of renal cancer. Regarding genetic research, this series has contributed to the identification of a germline mutation in the MITF gene that increases the risk of developing melanoma, renal cancer or both cancers and has interesting biological properties. The study of anogenital melanoma has shown that these melanomas could be associated with cutaneous melanoma in the same patient and it has also shown a high frequency of family history of melanoma associating mucosal and CM suggesting a shared genetic predisposition. Consequently dermatological screening or monitoring must include examination of both skin and mucosa in families with multiple cases of CM; and in case of a mucosal melanoma, a dermatological examination should be offered to relatives. The genetic mechanism has to be identified

Introdução: A escolha da via de acesso para tratamento paliativo da obstrução biliar nos tumores da confluência biliopancreática (TCBP) permanece incerta para os pacientes com baixo risco anestésico-cirúrgico ou longa expectativa de vida. Objetivo: Estudar a influência da derivação biliar mediante abordagem laparotômica e endoscópica nos resultados assistenciais e nos custos do tratamento paliativo dos TCBP. Método: Estudo coorte retrospectivo de prontuários dos pacientes portadores de TCBP submetidos ao tratamento paliativo endoscópico ou cirúrgico no Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP-USP), no período de 2002 a 2013, com análise de variáveis epidemiológicas, clínicas e assistenciais e dos custos. Resultados: Dentre os 150 pacientes com TCBP estudados, 92 (61,33%) foram submetidos à derivação das vias biliares por laparotomia (TL) e 58 (38,66%) por via endoscópica (TE), onde a prótese plástica foi utilizada na maioria dos casos (N = 38, 65,51%). Os grupos foram homogêneos para a maioria das variáveis epidemiológicas e clínicas antes dos procedimentos. As taxas de complicações precoces foram equivalentes na comparação dos grupos (55,17% para TE e 40,1% para TL), porém as complicações tardias foram mais frequentes no grupo TE (20,68% para TE e 10,34% para TL), o que se associou principalmente às recorrências das obstruções biliares. As curvas de sobrevida foram menores para TE. Não houve diferença significativa entre o custo mediano por procedimento no grupo TE (R$2.861,00) e TL (R$3.427,00) (p=0,3253). Por outro lado, o custo mediano total para o grupo TE (R$8.586,00) foi menor que o do grupo TL (R$12.810,00) (p=0,0001). Conclusão: a combinação das vantagens das duas modalidades de tratamento paliativo para os TCBP (maior sobrevida e eficácia na redução da colestase no grupo TL e menores tempo de internação e custo global no grupo TE) é uma meta a ser atingida e o acesso videolaparoscópico é uma alternativa a ser explorada. / Introduction: the advanced tumors of the biliopancreatic confluence (TCBP) often present with biliary obstruction, which can receive palliative treatment, through laparotomy, laparoscopic or endoscopic. Objective: to study the influence of laparotomy and endoscopic approaches in care results and costs of the palliative treatment of TCBP. Method: retrospective coorte study of medical records of patients with TCBP undergoing to the endoscopic and / or laparotomic palliation at the Hospital of Clinics of the Faculty of Medicine of Ribeirão Preto, University of São Paulo (HCFMRP-USP), from 2002 to 2013 with analysis of epidemiological variables, clinical, care and treatment costs. Results: among the 150 patients with TCBP studied, 92 (61.33%) underwent biliary bypass by laparotomy (TL) and 58 (38.66%) endoscopically (TE). The groups were homogeneous for most of the epidemiological and clinical variables before the procedures. The rates of early complications were similar between the groups (55.17% for TE and 40.1% for TL), but late complications were more frequent in the TE group (20.68% for TE and 10.34% for TL), which was mainly associated with the recurrence of biliary obstruction. The survival curves were lower for TE. The median cost of the procedure in the TE group (R$ 2,861.00) wasn´t different from TL (R$ 3,427.00) (p = 0,3253). On the other hand, the median total cost for the TE group (R$ 8,586.00) was lower than the TL group (R$ 12,810.00) (p = 0,0001). Conclusion: the combination of the advantages of the two methods of palliative treatment for TCBP (greater efficacy in reducing cholestasis in the TL group and lower length of stay and the overall costs in the TE group) is a goal to be achieved, and the laparoscopic access is an alternative to be explored.

L'adénocarcinome canalaire pancréatique (PDAC) est une maladie agressive dans le monde. En raison du manque d'outils de détection hautement sensibles et spécifiques à un stade précoce de la maladie et de traitements peu curatifs, la plupart des patients sont diagnostiqués à un stade incurable avec une mortalité élevée. Comprendre la pathologie moléculaire, en particulier le stade précoce de cette maladie mortelle, est d’une importance capitale pour améliorer les bons pronostics de ces patients. La première et principale partie de mes travaux reposait sur une analyse de profilage génétique dans laquelle ils mettaient en évidence le rôle de la signalisation TGFβ / Activine et du récepteur ALK4 au cours du développement de la PDAC, en plus des quatre gènes oncogéniques courants (KRAS, CDKN2A, TP53 et SMAD4). ). D'autre part, INHBA (codant pour ActivinA) en tant que membre clé des ligands de la superfamille TGFβ est une cible de l'activation oncogénique de Kras dans les cellules du canal pancréatique et a été désigné comme composant potentiel de la SASP par une analyse au sécrétome de cellules subissant une sénescence induite par Kras. . Le but de mes travaux est donc d’étudier l’impact de la signalisation ActivinA lors de l’initiation de la PDAC. Dans la première partie de mon projet, j'ai démontré qu'ActivinA était un facteur SASP protecteur de la tumeur, produit par les cellules sénescentes d'ADM / PanIN, qui limitent leur prolifération et leur expansion dans les lésions hautement prolifératives via son récepteur ALK4 lors de l'initiation du PDAC. De plus, nos travaux ont révélé que les cellules sénescentes Dclk1 + limitent l'expansion des lésions prénéoplasiques et ont un impact partiel sur le composant stromal soutenu par la signalisation ActivinA. En outre, j'ai également exploré les fonctions autocrines et paracrines de la signalisation ActivinA au dernier stade de la PDAC. Nous avons constaté que le manque de signalisation ActivinA-ALK4 chez la souris entraînait une augmentation de la capacité de prolifération des cellules tumorales et une accumulation réduite de cellules stromales, ce qui pourrait aider à expliquer leurs métastases variées et un temps de survie relativement plus long. En conclusion, mon travail donne un autre aperçu de la signalisation ActivinA et Dclk1 dans l'initiation de la PDAC et leur existence dans des cellules sénescentes au sein de lésions précurseurs pancréatiques de bas grade devrait être considérée comme une étape cruciale pour développer de nouvelles stratégies diagnostiques et thérapeutiques pour les patients atteints de PDAC / Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease worldwide and remains the ranking of 7th leading cause of cancer related death in the past 5 years. Because of the lack of highly sensitive and specific detective tools in an early stage of this disease and low curative treatments, most of the patients are diagnosed in an incurable stage and end up with a high mortality. Understanding the molecular pathology especially the early stage of this lethal disease is of great importance to improve the outcome of these patients. The first and major part of my work was based on gene profiling analysis in which they emphasized the role of TGFβ/Activin signalling and ALK4-receptor during the development of PDAC in addition to the four common oncogenic genes (KRAS, CDKN2A, TP53 and SMAD4). On the other hand, INHBA(encoding for ActivinA) as a key member of TGFβ-superfamily ligands is a target of Kras oncogenic activation in pancreatic duct cell and has been pointed a potential SASP candidate component through a secretome analysis of cells undergoing Kras induced senescence. Therefore, the aim of my work is to investigate the impact of ActivinA-signalling during PDAC initiation. In the first part of my project, I demonstrated that ActivinA as a tumour-protecting SASP factor, produced by ADM/PanINs senescent cells, that limit their proliferation and expansion into highly proliferative lesions through its ALK4 receptor in the initiation of PDAC. Furthermore, our work revealed that senescent Dclk1+ cells limit the expansion of preneoplastic lesions and partly impact the stromal component which is sustained by ActivinA-signalling. Besides, I also explored the autocrine and paracrine functions of ActivinA-signalling in the late stage of PDAC. We found that lack of ActivinA-ALK4 signalling in mice leads to an increased proliferative capacity in tumor cells and a reduced accumulation of stromal cells, which might help to explain their diverse metastasis and a relative longer survival time. To conclude, my work gives another insight of ActivinA-signalling and Dclk1 in the onset of pancreatic cancer and their existence in senescent cells within low grade pancreatic precursor lesions should be considered a crucial step for developing novel diagnostic and therapeutic strategies for PDAC patients

Ptf1a/p48 is a pancreas specific bHLH transcription factor that is required at early stages of embryonic development for pancreas formation and, during adulthood, for the proper exocrine pancreatic function. P48 also exerts an antiproliferative effect, which may exert a tumor suppressor activity. In this study, based on a yeast two-hybrid approach, we have identified new p48 partners that modulate the activity of p48. Among the newly identified putative interactors we found p/CAF, which is a coactivator that potentiates its transcriptional activity, and ICAT, an inhibitor of the &#946;-catenin/TCF signaling pathway. ICAT binds to p48 and is coexpressed with it in the pancreas during development and postnatally. Using different cellular models, ICAT overexpression in acinar tumor cells resulted in changes of the pancreatic specific gene expression pattern. Furthermore, high levels of ICAT inhibited the interaction between p48 and p/CAF. While this hetero-oligomeric complex is required for the acinar gene expression, ICAT itself is shown to be present in a reconstituted PTF1 complex in vivo. Importantly, altered ICAT expression is demonstrated in several histological types of pancreatic tumors, possibly contributing to their differentiation phenotype and neoplastic properties. / Ptf1a/p48 es un factor de transcripción bHLH específico del páncreas necesario durante los estadios tempranos del desarrollo embrionario para la formación del mismo, y para el correcto funcionamiento del páncreas exocrino en el adulto. P48 desempeña también una función antiproliferativa, la cual puede resultar en una actividad de supresión tumoral. En el presente estudio, basado en una estrategia de cribado de doble-híbrido en levadura, han sido identificadas nuevas proteínas que interaccionan y que modulan la actividad específica de p48. Entre las posibles proteínas que interaccionan y han sido identificadas de novo se encuentra p/CAF, un co-activador que potencia la actividad transcripcional de p48, y ICAT, un inhibidor de la vía de señalización de la &#946;-catenina. Se ha demostrado que ICAT se une a p48 y ambos son co-expresados en el páncreas durante el desarrollo y en el adulto. Utilizando diferentes modelos celulares, la sobreexpresión de ICAT en células tumorales acinares resultó en un cambio en el patrón de expresión de genes específicos del páncreas. Al mismo tiempo, se observó que niveles elevados de ICAT inhiben la interacción entre p48 y su co-activador p/CAF. Mientras que este complejo hetero-oligomérico es necesario para la expresión de los genes acinares, se demostró que ICAT está presente en un complejo PTF1 reconstituido in vivo. Finalmente, se observaron alteraciones en la expresión de ICAT en varios tipos histológicos de tumores pancreáticos, que posiblemente contribuyen a su fenotipo de diferenciación y propiedades neoplásicas.