The aim of this thesis was to establish the therapeutic value of the IFITM1 monoclonal antibodies and to design and develop therapeutically valuable recombinant monoclonal antibodies so as to study the implication of these novel antibodies in cancer therapy. Cancer metastasis is one of the main interests that has given rise to the design and development of innovative strategies for cancer therapeutics. The Interferon Induced Transmembrane Protein 1(IFITM1), a notable member of the IFITM family of proteins has been identified as one of the most up-regulated trans-membrane proteins in metastatic breast cancer and cervical adenocarcinoma. This interferon-regulated protein is also involved in cell migration, invasion in glioma and squamous cancers. This PhD aimed to study IFITM1 as a pro-invasive cancer target by the use of IFITM1 monoclonal antibodies that were raised against the extracellular domain of the human IFITM1 gene. The epitope mapping of IFITM1 revealed the binding activity of the IFITM1 monoclonal antibody. This gave the opportunity to design and generate to new IFITM1-specific molecular tools, in the form of recombinant IFITM1 targeted murine scFv antibody, IFITM1-CPG2 yeast fusion protein antibody for potential application in ADEPT as well as a Mouse-Human Chimeric IFITM1 antibody secreting mammalian cell line. The immunohistochemical staining of IFITM1 in tissue micro array from breast, colon and oeosphegal cancer has revealed that the majority of these cancers produce this protein. However, IFITM1 is over produced in cervical cancer indicating it’s selective over expression in cervical cells. This PhD endeavored to investigate the expression of IFITM1 at a translational and transcriptional level and to study the clinical significance of IFITM1 in cervical cancer. The antibody dependent cell mediated cytotoxic activity of the chimeric IFITM1 antibody was found to be cytotoxic to SiHa cells in vitro. In the future these molecular tools could be used to regulate and further characterize the activity of this transmembrane protein antibody. In an effort to better understand the mechanisms that regulate the activity and the over production of the IFITM1 gene and its interacting proteins, a proteomic screen of cervical cancer cells was carried out using data-independent SWATH-MS on an AB SCIEX TripleTOF™ mass spectrometer. This Mass Spec analysis provided us with a host of IFITM1 biomarkers and revealed that the IFITM1 gene and its binding proteins also cross link with the IRF1 pathway. The data presented in this thesis, demonstrates that the IFITM1 gene can be targeted to either stimulate or inhibit IFITIM1 signaling to engage IFITM1 as a potential pro-invasive extracellular receptor as a target in antibody cancer therapy. In summary, this thesis aimed to confirm the activity and the binding specificity of the IFITM1 antibody. Additionally, this thesis demonstrated a promising application of the recombinant antibody in the ADEPT technology. Characterization of IFITM1 mAb effector functions indicated that the antibody was cytotoxic to cervical cancer cells. This highlights an important element in the immune suppressive tumour microenvironment. And finally, this thesis also provides the basis for the production of recombinant mouse human chimeric antibodies that are a part of a new group of immunotherapeutic molecules paving the way for cancer therapeutics.

Les glioblastomes (GBMs) sont des tumeurs cérébrales au pronostic défavorable. La résistance aux thérapies actuelles et la rechute des GBMs pourraient être due à l'existence de cellules aux propriétés souches. L'objectif de ma thèse a été la caractérisation des cellules souches de GBMs (CSGs) isolées à partir de tumeurs. L'analyse du profil souche et de pluripotence des CSGs a montré qu'elles sont maintenues dans un état souche par SOX2 et que COL1A1 et IFITM1 peuvent être des cibles thérapeutiques potentielles. L'étude de la radiosensibilité des CSGs à travers l'analyse des courbes de clonogénicité a mis en évidence deux groupes dont un «atypique» pouvant être composé de sous-populations de cellules aux radiosensibilités différentes qu'il conviendra de caractériser. L'étude de la réparation a mis en évidence deux autres groupes dont un ayant un fort potentiel de réparation qui exprime plus fortement le gène RAD51 après irradiations. Le traitement par un inhibiteur spécifique de RAD51 ralentirait la capacité de réparation de ces cellules. Malgré cette hétérogénéité, l'inhibition de la voie Hedgehog (HH) par un vecteur glucuronylé de la cyclopamine, activé par le microenvironnement tumoral, inhibe la prolifération et l'auto-renouvellement des CSGs in vitro et ralentit la croissance tumorale in vivo. La voie HH semble être une cible thérapeutique intéressante commune à toutes les CSGs. Néanmoins, il est nécessaire de prendre en compte l'hétérogénéité dans les populations tumorales pour le développement de la médecine personnalisée. / Glioblastomas (GBMs) are brain tumors with a poor prognosis. Their resistance to current therapies and the occurrence of tumor relapse may be related to the existence of cells bearing stem cell characteristics. The aim of this PhD research was to characterize glioblastoma stem cells (GSCs) having been isolated from tumors. Analysis of the stemness and pluripotency profiles of GSCs indicated that their stemness states are maintained by SOX2 and that COL1A1 and IFITM1 may be potential therapeutic targets. Clonogenic studies of GSC radiosensitivity underscored the presence of two groups, one of them composed of sub-populations of cells with different degrees of radiosensitivity that have yet to be fully characterized. Study of DNA repair capacity highlighted two additional groups including one with high repair potential overexpressing the RAD51 gene after 4Gy. However, treatment with RAD51 inhibitor is likely to slow down repair of GSC lesions. Notwithstanding GSC heterogeneity, in our study inhibition of the Hedgehog pathway (HH) by a cyclopamine glucuronid prodrug, activated by the tumor microenvironment, inhibited in vitro proliferation and self-renewal in all the GSCs tested and slowed down tumor growth in vivo. Hence, HH pathway appears to be conserved among GSCs and constitutes an interesting potential therapeutic target. With regard to the development of personalized medicine, it is nevertheless highly advisable to take into account the pronounded heterogeneity of tumor populations.