(EN) Chronic lymphocytic leukemia (B-CLL) represents a disease of mature-like B-cells. Due to failed apoptosis but also due to enhanced proliferative signals, the leukemic B-cells accumulate in the peripheral blood, bone marrow, lymph nodes and spleen. The clinical course of B-CLL is very heterogeneous; in some patients B-CLL progresses very rapidly into an aggressive form. Such patients need therapy sooner while in other patients with indolent B-CLL the onset of therapy takes years. Several standard prognostic and disease progression markers are used for disease staging and monitoring, however a reliable marker that will suggest when to start therapy is unknown. Expression of small, non-coding microRNAs is often deregulated and represent important prognostic markers in variety of cancers including leukemia. Hence in our study we concentrated to miR-155, an important molecule regulating differentiation of hematopoietic cells, inflammation process and antibody production. Its aberrant expression was described in Hodgkin`s as well as in non-Hodgkin`s lymphoma, including indolent lymphoproliferations like B- CLL. Our results confirmed elevated levels of both, primary miR-155 transcript and mature form of miR-155 in our B-CLL patient samples (N=239). The aberrant expression of miR-155 in B-CLL samples...

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Atualmente, a Leucemia Linfocítica Crônica (LLC) pode ser dividida em dois grupos: um com mutações somáticas no gene da região variável da cadeia pesada da imunoglobulina (MIgVH) e outro sem mutações (NMIgVH). Alguns estudos mostraram que a expressão de CD38 na superfície das células B de LLC pode estar correlacionada com o estado mutacional do gene VHIg, entretanto, esses controversos. Estudos recentes mostraram que a expressão da proteína tirosina quinase Zap-70 está melhor associada com o estado mutacional do gene IgVH. O objetivo deste estudo foi avaliar a expressão de Zap-70 e CD38, por citometria de fluxo, nas células CD19+ de pacientes com LLC e correlacioná-los com o estádio clínico (EC), sobrevida livre de tratamento (SLT) e sobrevida global (SG). A expressão de Zap-70 e CD38 foi avaliada, em 144 de pacientes com LLC classificados nos estádios clínicos A, B e C de acordo com os critérios de Binet: 59 (41%) do EC-A, 38 (26%) do EC-B e 47 (33%) do EC-C. Foi observada menor positividade para Zap-70 e CD38 nos pacientes do EC-A do que nos EC-B e C. Quando avaliada a SLT nos pacientes do EC-A, os casos Zap-70+ assim como os CD38+ apresentaram menor SLT. A média de SG dos pacientes Zap-70+ e CD38+ foi menor quando comparado com os Zap-70- e CD38- entretanto quando correlacionada com o EC não foi observada diferença estatisticamente significante entre a expressão desses marcadores e o EC-A, B ou C. Pela analise combinada de CD38 e Zap-70, dividimos os pacientes em dois grupos (Zap-70-/CD38- e Zap-70+ ou CD38+). Observamos que a expressão positiva desses dois marcadores estava associada ao EC, uma vez que a grande maioria dos pacientes dos estádios B (74%) e C (66%) expressam Zap-70 ou CD38. Entretanto, os pacientes do EC-A, Zap-70+ ou CD38+, apresentaram SG menor quando comparado com os Zap-70-/CD38-. Essa diferença não foi observada nos pacientes do EC-B e do EC-C. Também foi observada menor SLT nos pacientes no EC-A, Zap-70+ ou CD38+. Esses resultados sugerem que análise combinada de Zap-70 e CD38 podem ser empregadas na avaliação dos pacientes do EC-A para se acompanhar a evolução clinica desse grupo de pacientes. Porém, estudos adicionais devem ser realizados para se validar a utilização clínica desses marcadores. / Actually, chronic lymphocytic leukemia (CLL) can be divided in two subsets: one with somatically mutated immunoglobulin heavy-chain variable-region genes (MIgVH) and other with unmutated sequences. (UMIgVH). Some studies have shown that CD38 expression in CLL cells are correlated with IgVH mutational status. However, the value of CD38 as surrogate IgVH mutational status is controversial. Recent studies, have found that Zap-70 protein tyrosine kinase expression is strongly associated with the mutational status IgVH. The aim of this study was to evaluate the Zap-70 and CD38 expression, for flow cytometry, in CD19+ LLC cells and correlate with the Binet’s staging system, treatment-free survival (TFS) and a overall survival (OS). Zap-70 and CD38 was evaluated, in 144 CLL patients that was classified in A, B and C Binet’s staging system: 59 (41%) in stage A, 38 (26%) in B and 47 (33%) in C. We observed low Zap-70 and CD38 expression in stage A patients than in stage B and C cases. When we analyzed the TFS in stage A patients Zap-70+ and CD38+ patients showed shorter TFS than Zap-70- and CD38-. Then we observed that the OS of Zap-70+ and CD38+ patients was, also, shorter than Zap-70- and CD38- cases. However, statistical differences was not found when Zap-70 and CD38 expression was correlated with stage A, B or C Binet’s staging system. To understand the associated Zap-70 and CD38 expression, we divided the CLL patients in two subgroups (Zap-70-/CD38 - and Zap-70+ or CD38+). We observed that CD38+ or Zap-70+ was associated Binet’s staging system, once most of stage B (74%) and C (66%) patients are Zap-70+ or CD38+. However, stage A patients, Zap-70+ or CD38+, showed shorter OS than Zap-70-/CD38-. These differences were not observed in stage B and C patients. Shorter TFS was also observed in the Zap-70+ or CD38+ stage A patients. These results suggest that combined analysis of Zap-70 and CD38 can be used to evaluate stage A patients to observe the clinical evolution of the disease. Nevertheless, other studies must be carried to confirm the clinical use of these markers.

在台灣的英文學習環境中， 閱讀能力ㄧ向被視為學習中最重要的ㄧ環 ， 然而， 閱讀所帶來的沉重負擔， 讓許多學生在有限的教學時數之下往往成為了犧牲品，特別是低成就者。班上參差不齊的英文程度,也對老師造成了教學上極大的困擾。 本研究旨在探討 ，以合作式學習法來縮短學習者程度上的差異，進而提升整體的閱讀能力。此外, 互動式閱讀技巧也分別在實驗組與控制組中教授， 以檢視其對閱讀能力的影響。 參與本研究的學生為 79名台北某公立高中的兩班九十四學年度高一新生， 實驗組施以合作式學習法，控制組則為傳統老師講授的方式， 兩組在同一時間內閱讀同一本教科書， 並分別施以前測， 後測。 最後， 並再針對所有研究對象施以問卷調查， 以期了解研究對象對合作式學習法及互動式閱讀技巧之回應。此外, 老師上課的觀察紀錄及小組的檢視表也一併在本研究中被採用。 本研究的結果摘要如下: 1. 在學生閱讀成就方面，實驗組以漸進的方式，最後超越控制組。 2. 在一學期互動式閱讀技巧實施之後， 研究對象之閱讀能力明顯提升。 3. 在實驗組中 ，高、中、 低成就者對合作式學習法展現許多雷同與少許差異的反應，但整體而言，皆傾向於正面的肯定。 4. 閱讀技巧在實驗組與控制組中似有明顯之差異， 顯見研究對象會依教學活動採取不同的閱讀技巧。 根據研究結果， 本論文擬提出對現行高中閱讀教學之建議，俾為教師及未來研究者提供參考。 / In an EFL environment in Taiwan, reading is regarded as the most essential skill. However, for most students, abundance in reading material makes them feel stressful--especially the weaker ones who tend to be sacrificed due to limited instruction time. For teachers, how to deal with a big mixed-level class has therefore become the most important task. An aim of this study was to examine the effectiveness of cooperative language learning (CLL) skills in bridging gap among students with differing academic abilities and in enhancing students' overall reading comprehension. In addition, the interactive reading approach was adopted in both the experimental and the control groups to examine its effect upon them. Participants of this study included 79 tenth-graders from two intact classes in one public senior high school in Taipei in the fall semester of 2005. The experimental group was engaged in three CLL activities and the control group was instructed in the traditional teacher-centered methods. Both groups were taught by the researcher with the interactive reading approach. During the span of this study, the participants in both groups were assigned to read nine lessons from the textbook. In the meantime, they were instructed under the CLL methods and the traditional teacher-centered methods respectively. Besides, they were given a pretest and four posttests during and after the study. In time, two questionnaires were adopted: one for investigating the reading strategies used by the participants in both groups and the other for measuring the CLL group participants' attitudes and responses of the CLL group toward CLL teaching. Besides, the teacher's classroom observation and the group processing checklists were also employed in this study. After four months of experiment, the main results of this study can now be summarized as follows: 1. The experimental group gradually outscored the control group on the reading comprehension test during the experiment. 2. The participants’ reading comprehension ability improved significantly after the implementation of interactive reading approach. 3. The results showed some similarities and differences among the high/low achievers and the average students in their perceptions toward the CLL. However, the participants' attitudes toward and responses to CLL may be described as being supportive and positive. 4. The adoption of reading strategies seemed diverse between the two groups. On the whole, when exposed to different teaching activities, the participants adopted different reading strategies accordingly. This study concludes that the effects of CLL might be better than those of individual learning in a big class on senior high school students' reading proficiency. It also suggests that the interactive reading approach can be used to enhance senior high school students' reading ability.

Η παρούσα διδακτορική διατριβή έχει ως στόχο τη δημιουργία ενός αποδοτικού μοντέλου για το Λειτουργικό Συνδυασμό Βιο-Ιατρικών δεδομένων (BioMedical data integration). Ξεκινώντας από τη σχεδιαστική ανάλυση της ιατρικής γνώσης και των προβλημάτων που προκύπτουν από τον τρόπο παραγωγής των ιατρικών δεδομένων, προχωρεί στην επίλυση των επιμέρους θεμάτων Λειτουργικού Συνδυασμού εντός ενός συγκεκριμένου ιατρικού πεδίου και καταλήγει στον ολοκληρωμένο Λειτουργικό Συνδυασμό ιατρικών δεδομένων προερχόμενων από διαφορετικές πηγές και πεδία γνώσης. Συνεχίζει με τη σχεδίαση ενός μοντέλου βάσεων δεδομένων που ακολουθεί «οριζόντια» λογική και είναι αρκετά αποδοτικό ώστε να αποκρίνεται σε πολύπλοκα και ευρείας κλίμακας ερωτήματα σε πραγματικό χρόνο. Καταλήγει με την παρουσίαση μίας ολοκληρωμένης εφαρμογής η οποία εκμεταλλευόμενη τα πλεονεκτήματα του Λειτουργικού Συνδυασμού και της οριζόντιας δομής των δεδομένων είναι σε θέση να διαχειριστεί εξετάσεις προερχόμενες από κάθε κυτταρομετρητή ροής και συνδυάζοντάς αυτές με τις υπόλοιπες αιματολογικές κλινικοεργαστηριακές εξετάσεις να απαντά σε καθημερινά και σύνθετα ερευνητικά, ιατρικά ερωτήματα. Τα πρωτότυπα ερευνητικά αποτελέσματα που προέκυψαν στα πλαίσια της παρούσης εργασίας δημοσιεύτηκαν σε έγκυρα διεθνή περιοδικά και σε διεθνή και ελληνικά συνέδρια με κριτές. / Current dissertation focuses on the creation of an efficient model for Bio-medical data integration. Starting with an analytical approach of the medical knowledge and the problems that may occur cause of the way that medical data are produced, continues with the necessary solutions for single domain data integration and concludes with the proposal of a working framework for mass data integration, originating from multiple medical domains. The proposed integration model is based on the “horizontal” logic of a database design and it’s efficient enough to produce query results in real time, even for complex real-life medical questions. The proof of concept of the working framework and its goals for mass data integration is achieved through the presentation of a medical information system. The presented system, by taking advantage of the “horizontal” database design, is able to manage Flow Cytometry measurements, originating for any available hardware and by integrating the cytometric data with other types of hematological data is able to give answers to everyday and research medical questions. All original research results that produced within the scope of this dissertation were published in international research journals and medical conferences.

Η Β-χρόνια Λεμφογενής Λευχαιμία (Β-ΧΛΛ) αποτελεί τον πιο κοινό τύπο λευχαιμίας στο Δυτικό κόσμο. Η πρόγνωσή της θεωρείται ως ένα από τα πιο ενδιαφέροντα προβλήματα απόφασης στην κλινική έρευνα και πρακτική. Για διάφορους κλινικούς και εργαστηριακούς δείκτες είναι γνωστό ότι σχετίζονται με την εξέλιξη της νόσου. Για τις παραμέτρους, όμως, που εξάγονται με ανάλυση κυτταρομετρίας ροής, οι οποίες αποτελούν τον ακρογωνιαίο λίθο της διαδικασίας διάγνωσης της νόσου, το αν προσφέρουν επιπρόσθετη προγνωστική πληροφορία αποτελεί ανοιχτό πρόβλημα. Στη διατριβή αυτή προτείνουμε ένα σύστημα υποβοήθησης για τις αποφάσεις των ειδικών του πεδίου, το οποίο πραγματοποιεί πολυπαραμετρική πρόγνωση ασθενών με Β-ΧΛΛ, συνδυάζοντας τη χρήση ποικίλων ετερογενών προγνωστικών δεικτών (κλινικών, εργαστηριακών και κυτταρομετρίας ροής) που σχετίζονται με τη νόσο. Η διάγνωση της Β-ΧΛΛ βασίζεται κυρίως στη μελέτη του αντιγονικού φαινότυπου των κυττάρων των ασθενών, η οποία διενεργείται με κυτταρομετρία ροής. Αν και η διαδικασία που ακολουθείται κατά την ανάλυση αυτή είναι σαφώς ορισμένη, ο τρόπος με τον οποίο οι εργαστηριακοί υπεύθυνοι την πραγματοποιούν παραδοσιακά χαρακτηρίζεται από ανακρίβεια και υποκειμενικότητα. Καθώς η τεχνολογία της κυτταρομετρίας ροής εξελίσσεται ραγδαία, γίνεται όλο και πιο επιτακτική η ανάγκη για την ανάπτυξη αυτοματοποιημένων μεθόδων ανάλυσης των δεδομένων που παράγει. Σε αυτά τα πλαίσια, παρουσιάζουμε ένα χρήσιμο παράδειγμα αυτοματοποιημένης ανάλυσης κυτταρομετρικών δεδομένων, η οποία δεν απαιτεί την άμεση επίβλεψη των ειδικών, για τη διάγνωση ασθενών με Β-ΧΛΛ. Οι τιμές των χαρακτηριστικών παραμέτρων που εξάγονται με εφαρμογή της προτεινόμενης μεθοδολογίας, ενσωματώνονται κατόπιν στο προαναφερθέν προγνωστικό σύστημα. Ανάγοντας το πρόβλημα της πρόγνωσης της Β-ΧΛΛ σε ένα στιγμιότυπο ταξινόμησης προτύπων, καθώς και προσομοιώνοντας κάθε ένα από τα βήματα της διαδικασίας της διάγνωσης της νόσου με ένα στιγμιότυπο συσταδοποίησης δεδομένων, αντιμετωπίσαμε τα δύο προβλήματα εφαρμόζοντας τεχνικές στατιστικής μάθησης. Εστιάσαμε σε μεθοδολογίες δικτύων πεποίθησης, χρησιμοποιώντας συγκεκριμένα το naïve-Bayes μοντέλο και για τις δύο περιπτώσεις, στην επιβλεπόμενη και στη μη επιβλεπόμενη εκδοχή του, αντίστοιχα. Τα χαρακτηριστικά και η φύση των δεδομένων (κυρίως των κυτταρομετρικών) που παράγονται από έναν παθολογικό υποκείμενο μηχανισμό, όπως αυτός της νόσου, δεν ευνοούν την απευθείας εφαρμογή του παραπάνω μοντέλου στο εκάστοτε στιγμιότυπο. Για το λόγο αυτό, συνδυάσαμε την εφαρμογή του naïve-Bayes μοντέλου με κατάλληλες ευρετικές αλγοριθμικές διαδικασίες, για την επίτευξη καλύτερων αποτελεσμάτων, με κριτήριο βέλτιστου όχι μόνο κάποιες συχνά χρησιμοποιούμενες μετρικές αποτίμησης αλγόριθμων, αλλά και τη γνώμη των αιματολόγων. Χάρη στην ιδιότητά τους να ενσωματώνουν την έμπειρη γνώση των ειδικών ως εκ των προτέρων πληροφορία αρχικοποίησης των μεθόδων μάθησής τους, οι Bayesian μεθοδολογίες κρίνονται ως οι πλέον κατάλληλες για την εφαρμογή τους σε τέτοιου τύπου προβλήματα. / B-Chronic Lymphocytic Leukemia (B-CLL) is known to be the most common type of leukemia in the Western world. Its prognosis remains one of the most interesting decision problems in clinical research and practice. Various clinical and laboratory factors are known to be associated with the evolution of the disease. However, for the parameters obtained by flow cytometry analysis, that are traditionally utilized as the cornerstone during the diagnosis procedure of the disease, whether they offer additional prognostic information is an open issue. In this dissertation, we propose a decision support system to the hematologists, that provides multiparametric B-CLL patients’ prognosis, combining the usage of diverse heterogeneous factors (clinical, laboratory and flow cytometry) associated with the disease. B-CLL diagnosis is primarily derived from the study of the antigenic phenotype of the patients’ blood cells, which is held with flow cytometry analysis. Despite the fact that the method of the analysis is well defined, the process traditionally followed by the laboratory experts is characterized by amounts of inexactness and subjectivity. As flow cytometry technology advances rapidly, the need for adequate automated (computer-assisted) analysis methodologies on the data it produces is accordingly increasing. In this context, we present a useful paradigm of automated analysis of flow cytometry data, that does not require the direct supervision of the expert, for B-CLL patients’ diagnosis. The values of the flow cytometry characteristic parameters extracted by applying the proposed methodology are afterward incorporated to the prognostic system for B-CLL mentioned above. By reducing the B-CLL prognosis problem to an instance of the pattern classification problem, as well as by simulating each step of the B-CLL diagnosis procedure with an instance of the data classification problem, we proceeded with applying statistical learning techniques. We focused on Bayesian network methodologies and utilized the naïve-Bayes model for both cases, in its supervised and unsupervised version, respectively. The characteristics of the data (especially of the flow cytometry ones) generated by a pathological underlying mechanism, like the disease’s one, did not encourage the direct use of the above model. Therefore, we combined the naïve-Bayes model with a set of suitable heuristic algorithmic procedures to obtain better results, not only with respect to some commonly used algorithmic optimality metrics, but also by considering the experts’ opinion. Due to their ability of incorporating the expert knowledge as a priori initial information to their learning methods, Bayesian methodologies are considered as the most appropriate ones to make use of in such types of applications.

Atualmente, a Leucemia Linfocítica Crônica (LLC) pode ser dividida em dois grupos: um com mutações somáticas no gene da região variável da cadeia pesada da imunoglobulina (MIgVH) e outro sem mutações (NMIgVH). Alguns estudos mostraram que a expressão de CD38 na superfície das células B de LLC pode estar correlacionada com o estado mutacional do gene VHIg, entretanto, esses controversos. Estudos recentes mostraram que a expressão da proteína tirosina quinase Zap-70 está melhor associada com o estado mutacional do gene IgVH. O objetivo deste estudo foi avaliar a expressão de Zap-70 e CD38, por citometria de fluxo, nas células CD19+ de pacientes com LLC e correlacioná-los com o estádio clínico (EC), sobrevida livre de tratamento (SLT) e sobrevida global (SG). A expressão de Zap-70 e CD38 foi avaliada, em 144 de pacientes com LLC classificados nos estádios clínicos A, B e C de acordo com os critérios de Binet: 59 (41%) do EC-A, 38 (26%) do EC-B e 47 (33%) do EC-C. Foi observada menor positividade para Zap-70 e CD38 nos pacientes do EC-A do que nos EC-B e C. Quando avaliada a SLT nos pacientes do EC-A, os casos Zap-70+ assim como os CD38+ apresentaram menor SLT. A média de SG dos pacientes Zap-70+ e CD38+ foi menor quando comparado com os Zap-70- e CD38- entretanto quando correlacionada com o EC não foi observada diferença estatisticamente significante entre a expressão desses marcadores e o EC-A, B ou C. Pela analise combinada de CD38 e Zap-70, dividimos os pacientes em dois grupos (Zap-70-/CD38- e Zap-70+ ou CD38+). Observamos que a expressão positiva desses dois marcadores estava associada ao EC, uma vez que a grande maioria dos pacientes dos estádios B (74%) e C (66%) expressam Zap-70 ou CD38. Entretanto, os pacientes do EC-A, Zap-70+ ou CD38+, apresentaram SG menor quando comparado com os Zap-70-/CD38-. Essa diferença não foi observada nos pacientes do EC-B e do EC-C. Também foi observada menor SLT nos pacientes no EC-A, Zap-70+ ou CD38+. Esses resultados sugerem que análise combinada de Zap-70 e CD38 podem ser empregadas na avaliação dos pacientes do EC-A para se acompanhar a evolução clinica desse grupo de pacientes. Porém, estudos adicionais devem ser realizados para se validar a utilização clínica desses marcadores. / Actually, chronic lymphocytic leukemia (CLL) can be divided in two subsets: one with somatically mutated immunoglobulin heavy-chain variable-region genes (MIgVH) and other with unmutated sequences. (UMIgVH). Some studies have shown that CD38 expression in CLL cells are correlated with IgVH mutational status. However, the value of CD38 as surrogate IgVH mutational status is controversial. Recent studies, have found that Zap-70 protein tyrosine kinase expression is strongly associated with the mutational status IgVH. The aim of this study was to evaluate the Zap-70 and CD38 expression, for flow cytometry, in CD19+ LLC cells and correlate with the Binet’s staging system, treatment-free survival (TFS) and a overall survival (OS). Zap-70 and CD38 was evaluated, in 144 CLL patients that was classified in A, B and C Binet’s staging system: 59 (41%) in stage A, 38 (26%) in B and 47 (33%) in C. We observed low Zap-70 and CD38 expression in stage A patients than in stage B and C cases. When we analyzed the TFS in stage A patients Zap-70+ and CD38+ patients showed shorter TFS than Zap-70- and CD38-. Then we observed that the OS of Zap-70+ and CD38+ patients was, also, shorter than Zap-70- and CD38- cases. However, statistical differences was not found when Zap-70 and CD38 expression was correlated with stage A, B or C Binet’s staging system. To understand the associated Zap-70 and CD38 expression, we divided the CLL patients in two subgroups (Zap-70-/CD38 - and Zap-70+ or CD38+). We observed that CD38+ or Zap-70+ was associated Binet’s staging system, once most of stage B (74%) and C (66%) patients are Zap-70+ or CD38+. However, stage A patients, Zap-70+ or CD38+, showed shorter OS than Zap-70-/CD38-. These differences were not observed in stage B and C patients. Shorter TFS was also observed in the Zap-70+ or CD38+ stage A patients. These results suggest that combined analysis of Zap-70 and CD38 can be used to evaluate stage A patients to observe the clinical evolution of the disease. Nevertheless, other studies must be carried to confirm the clinical use of these markers.

Nous avons identifié une nouvelle forme de phospho-S27-S33-Ku70 constitutivement surexprimée dans des cellules issues de la leucémie lymphocytaire chronique résistante à la chimiothérapie basée sur des agents alkylants de l’ADN et/ou analogues nucléotidiques. La protéine Ku70 est une protéine essentielle du maintien de la stabilité génomique par son rôle dans la réparation non-homologue (système NHEJ) des cassures double brin de l’ADN (CDB) et par sa fonction télomérique. Le laboratoire d’accueil a déjà démontré, in vitro et in vivo, dans les cellules LLC résistantes une altération de la réparation par le système NHEJ et un dysfonctionnement télomérique. Le travail de thèse a porté sur la caractérisation fonctionnelle de cette nouvelle forme phospho-S27-S33-Ku70. Pour ceci, nous avons utilisé des vecteurs d’expression permettant simultanément d’inhiber l’expression du Ku70 endogène (shRNA) et d’exprimer de façon épisomale différentes formes de Ku70 exogène. Ainsi, nous avons démontré : i) une stricte colocalisation de pS27-pS33-Ku70 avec les foyers γ-H2AX; ii) des cassures double brin (DSB) induisent la phosphorylation de S27-S33-Ku70 sous forme hétérodimère avec Ku80. Cette phosphorylation a lieu quelques minutes après le stress génotoxique et implique l'activité et l'interaction physique avec pS2056-DNA-PKcs, reliant ainsi pS27-pS33-Ku70 au système NHEJ ; iii) les cellules exprimant la forme sauvage exogène S27-S33-Ku70 ou la forme phosphomimétique E27-E33-Ku70 présentent une cinétique de réparation de l’ADN plus rapide que celle des cellules exprimant la forme mutée A27-A33-Ku70. Cependant, iv) la forme sauvage de Ku70 contribue à un niveau plus élevé d'aberrations structurales chromosomiques après la première division cellulaire suite à un stress génotoxique indiquant une infidélité lors de la réparation des dommages de l’ADN. En outre, les cellules exprimant A27-A33-Ku70 possèdent un index cellulaire plus élevé qui est corrélé avec une activation de la voie β-caténine. En adéquation avec sa surexpression dans la forme résistante de la LLC, l’ensemble de ces résultats suggère un rôle oncogénique de la forme phosphorylée de Ku70. Nous avons ensuite testé l’effet des nanodiamants hydrogénés (ND-H) dans des lignées exprimant différentes formes de Ku70. Grâce à leurs propriétés physico-chimiques les ND-H sont capables de potentialiser sous irradiation la production intracellulaire des espèces réactives de l’oxygène (ROS) et ainsi augmenter le taux des cassures (simple et double brin de l’ADN) et solliciter d’avantage le système de réparation de l’ADN. Nous observons que indépendamment de la forme exprimée de Ku70, ce double traitement induisait la sénescence cellulaire ; une découverte d’un intérêt à la fois fondamental (compréhension des voies apoptotiques vs senescence) et d’utilité pharmacologique potentielle. / We have identified a new form of phospho-S27-S33-Ku70 constitutively overexpressed in a subset of chronic lymphocytic leukemia (CLL) B cells resistant to apoptosis induced by DNA double strand breaks (DSB). Ku70 is one of the essential proteins involved in the maintenance of genomic stability through its role in DNA double strand break repair (non-homologous end-joining, NHEJ) and in telomeric protection.Laboratory previously established that resistant CLL cells disclose an upregulated NHEJ DNA repair and an impaired structure of telomeres. The goal of this thesis was to characterize the biological function(s) of this new form of Ku70. For this purpose we have constructed specific EBV-based vectors (siRNA / cDNA) enabling a simultaneous inhibition of endogenous Ku70 and an expression of different forms (mutated, wild, phosphomimetic at ser27-33) of Ku70 resistant to siRNA. Thus, we showed: i) a strict colocalisation of phospho-Ku70 with γ-H2AX foci; ii) that DSB induces the phosphorylation of Ku70 within minutes after genotoxic stress in heterodimer complex Ku70/Ku80. This phosphorylation necessitates both the physical interaction and the activity of pS2056-DNA-PKcs and/or ATM, linking phospho-Ku70 to NHEJ-mediated DNA DSB repair; iii) cells expressing mutated A27-A33-Ku70 exhibit a delayed G2/M cell cycle arrest, slower kinetic of DNA repair, lower level of genotoxic stress-induced chromosomal aberrations, and a higher cellular impedance correlated with translocation of transcriptional factor β-catenin from cytoplasmic membrane to the nucleus. Together, these data unveil an involvement of phospho-Ku70 in fast and inaccurate DNA repair; new paradigm for NHEJ regulation and to the control of resistance and maintenance of malignant cells.In parallel, we have initiated experimental approaches to explore other potential roles of phospho-Ku70. Especially, we were interested to determine whether it could play a role in an initiation of cell senescence induced by combined cells’ treatment by hydrogenated nanodiamonds (H-NDs) particles and ionizing irradiation. H-NDs exhibit positive surface charge in aqueous solutions allowing, when irradiated by photons, electrons’ emission and the release of reactive oxygen species (ROS) causing DNA damage. Effectively, we have established an intracellular increase of ROS that drive cell cycle arrest in G1/S in addition to the G2 arrest activated by irradiation alone. Finally, cells underwent the senescence process characterized byγ-galactosidaze activity, persistent large γ-H2AX foci and senescence-associated heterochromatinisation. Noteworthy, the senescence induced in this way occurred independently of Ku70 (ser27-ser33) status and irrespectively of cell resistance to genotoxic agents administrated alone; a finding of potential use in clinical trials.

Genomic integrity is important for living cells' correct functioning and propagation. Deoxyribonucleic acid as a molecule is a subject to chemical reactions with agents that can come from environment as well as from internal metabolism processes. These reactions can induce damage to DNA and thus compromise the genetic information, and result in disease and death of an organism. To mitigate the damage to DNA, cells have evolved to have multiple DNA repair pathways. Presented here is a computational study of DNA repair genes. The structure of the Homo sapiens direct DNA repair gene ALKBH1 is predicted utilizing homology modeling methods and using AlkB and DBL proteins as templates. Analysis of the obtained structure and molecular dynamics simulations give insights into potentially functionally important residues of the protein. In particular, zinc finger domains are predicted, and lysines that could perform catalytic activities are investigated. Subsequent mutagenesis experiments revealed the effect of the residues predicted to form zinc fingers on activity of ALKBH1. Structure and dynamics of AlkD, a Bascillus cereus base excision DNA repair protein is also studied. This protein has been shown to bind DNA with large alkyl adducts and perform excision catalysis without base flipping which is characteristic to other enzymes in the same family. MD simulations of AlkD revealed that B helix, which interacts with DNA, has higher fluctuations when AlkD is not bound to DNA, and thus could have a role in binding and recognition of DNA. For the purpose of finding biomarkers and to further our understanding of a mode of action of DNA repair genes, statistical methods were applied to identify mutations that are linked to cancer phenotypes. Analysis was based on case-control studies of patients with cancers of prostate, breast, pancreas, lung as well as chronic lymphocytic leukemia from NCBI dbGAP database. Those mutations that result in missense mutations were further investigated. In particular, extensive MD simulations and experimental investigations were performed on the mutation in the ALKBH7 gene that was found to be linked to prostate cancer.

L’axe adénosinergique est au cœur de divers processus pathophysiologiques. L’enzyme CD73 joue un rôle pivot dans la génération de l’adénosine en catalysant la déphosphorylation de l’adénosine monophosphate. L’adénosine contribue à un éventail large de processus biologiques et pathologiques, principalement via l’activation de récepteurs transmembranaires. L’adénosine est principalement reconnue pour son activité régulatrice des cellules immunitaires et CD73 pour son rôle dans l’accumulation de l’adénosine dans le microenvironnement tumoral. En effet, en altérant la réponse immunitaire anti-tumorale via l’inhibition des fonctions effectrices de divers types de cellules immunes, CD73 et l’adénosine sont fréquemment associés à la progression tumorale et s’inscrivent comme cibles thérapeutiques intéressantes. Les rôles de CD73 et l’adénosine dans d’autres processus immunitaires physiologiques ne sont pas tous aussi bien compris, notamment concernant les processus d’immunisations. En utilisant un modèle murin d’immunisation contre le pneumocoque, cette thèse démontre un rôle positif, mais non essentiel, de CD73 et de l’adénosine dans la commutation isotypique des lymphocytes B et la génération d’une immunité protectrice contre l’infection au S. pneumoniae. Cette découverte est pertinente au développement de stratégies thérapeutiques afin d’augmenter l’efficacité d’immunisation dépendante des cellules B, plus particulièrement chez les populations à risque en bas âge. Ensuite, alors que la modulation de l’axe adénosinergique, notamment via l’inhibition de CD73, est une avenue thérapeutique étudiée dans divers contextes de tumeurs solides, ce potentiel thérapeutique demeure largement inexploré dans des modèles de néoplasmes sanguins. En utilisant un modèle de souris transgénique de leucémie spontanée, cette thèse démontre un rôle pro-tumorigénique, avec un biais sexuel, de CD73 dans la leucémie lymphoïde chronique des lymphocytes B (LLC), via l’altération de l’immunité anti-tumorale. Enfin, alors que les rôles immunosuppressifs de CD73 et l’adénosine sont bien décrits, leurs activités pro-tumorigéniques qui s’étendent au-delà de l’immunité anti-tumorale sont peu connues. En accord avec la littérature, cette thèse explore plusieurs hypothèses selon lesquelles CD73 module l’activité métabolique mitochondriale des cellules cancéreuses. Les résultats présentés dans cette thèse suggèrent un rôle pro-tumorigénique à l’enzyme CD73, indépendant de la signalisation adénosinergique et de l’inhibition de l’immunité anti-tumorale, qui favorise la flexibilité métabolique et plus particulièrement la respiration mitochondriale des cellules cancéreuses, via la voie de récupération de la biosynthèse du nicotinamide (NAD+). En résumé, cette thèse apporte plusieurs précisions quant aux rôles biologiques de l’enzyme CD73 qui sont pertinents à l’immunisation dépendante des lymphocytes B, à la pathogénèse de la LLC ainsi qu’à la régulation de l’activité métabolique des cellules cancéreuses. Cette thèse offre de nouvelles pistes de réflexion quant au potentiel thérapeutique que renferme l’axe adénosinergique et plus particulièrement CD73, en approfondissant nos connaissances quant à l’éventail de ses fonctions. / The adenosinergic axis is central to a plethora of pathophysiological processes. The enzyme CD73 is key to the generation of adenosine by catalyzing the dephosphorylation of adenosine monophosphate. Adenosine’s contribution to biological and pathological processes is mainly carried through the activation of transmembrane receptors. Adenosine is mostly appreciated for its regulatory activity on a variety of immunes cells whereas CD73 is often referred to the enzyme responsible for adenosine accumulation within tumor microenvironment. Thus, by hindering antitumoral immune responses, CD73 and adenosine are frequently associated with cancer progression and targeting these offers great therapeutic potential in clinic. CD73 and adenosine’s role in other immune physiological processes are not fully understood, notably regarding immunization processes. Using a murine model of pneumococcal immunization, this thesis herein demonstrates a positive, but non-essential, role for CD73 and adenosine in B cells’ isotype class switching required to protective immunity against S. pneumoniae. This finding is particularly relevant to the development of novel strategies aimed at enhancing B cell-dependent immunization in high-risk populations such as young infants. While targeting the adenosinergic axis, particularly CD73, was extensively proven efficient in restoring antitumor immunity in many solid tumor contexts, its therapeutic potential in blood neoplastic malignancies remain largely unexplored. Using a transgenic mouse model of spontaneous leukemia, this thesis identifies a sex-oriented pro-tumorigenic role for CD73 in favoring B cells chronic lymphocytic leukemia (CLL) progression, through the inhibition of antitumor immunity. Finally, while immunosuppression by CD73 and adenosine is well described in cancer, other immune-independent pro-tumorigenic roles of CD73 are poorly understood. In accordance with literature, this thesis explores various hypotheses by which CD73 regulates cancer cells’ mitochondrial metabolic activity. Results presented herein suggest an immune- and adenosine signaling-independent pro-tumorigenic function for CD73 in favoring cancer cells’ metabolic flexibility and more particularly mitochondrial respiration through the nicotinamide (NAD+) salvage biosynthesis pathway. In sum, this thesis brings many insights into CD73’s biological functions relevant to B cells-dependent immunization, in CLL pathogenesis and in cancer cells’ metabolic activity. By expanding our knowledge of the extend of CD73’s biological functions, this thesis further discusses novel potential therapeutic opportunities.