L'objectif de cette thèse concerne la possibilité d'améliorer le diagnostic et la thérapie des gliomes par le ciblage des intégrines à l’aide du RGD et par le développement d'agents multimodaux de type alcoxyamine. L’étude de l’internalisation du RGD révèle une régulation par la densité cellulaire, paramètre histologique dans la catégorisation des gliomes. Dans notre modèle, la densité cellulaire impacte la contribution de l’endocytose clathrine-dépendante et le métabolisme mais n’influence pas le rôle du cytosquelette. La régulation de l’internalisation des peptides RGD par la densité cellulaire reste à mieux comprendre afin de perfectionner les agents utilisant ce ciblage pour l’imagerie et le diagnostic des gliomes. Dans le même temps, les propriétés multimodales des alcoxyamines ont été évaluées àdes fins théranostiques. Ces molécules s’homolysent spontanément pour libérer un nitroxyde et un radical alkylant cytotoxique pouvant en plus induire une réactivation immunitaire antitumorale. Le nitroxyde est un agent de contraste pour l’IRM rehaussée par effet Overhauser. Le fort rehaussement du signal observé à proximité du nitroxyde assure un suivi en temps réel de l’apparition de l’agent alkylant. L’adaptation des alcoxyamines pour une homolyse conditionnelle dans le gliome permettrait une action thérapeutique avec un contrôle spatial et un suivi temporel du composé cytotoxique. L’acheminement de molécules d’intérêt vers la cible est rendu difficile par la présence de barrières physiologiques. Dans ce travail, la progression de nanoparticules par la voie intratrachéale peut se substituer à celle intraveineuse avec une augmentation du temps de rétention dans le gliome. / The aim of this thesis is to improve the diagnostic and the therapy of glioma through both the integrin targeting by RGD and the development of Alkoxyamine as multimodal agent. The RGD internalization is regulated by the cellular density, a histologic parameterfor the glioma classification. In our model, the cellular density increases the contribution of both the clathrin-mediated endocytosis and the metabolism but not the one of the cytoskeletal. A better knowledge about the RGD internalization regulation by the cell density could help the MRI probe development for glioma diagnosis. Properties of alkoxyamine as multimodal agent were evaluated to perform theranostic. The spontaneous alkoxyamine homolysis give a nitroxide radical and a cytotoxic alkylating agent that could induce immune reactivation against the tumor. This nitroxide is an Overhauser enhanced MRI contrast agent. The strong signal enhancement in the nitroxide vicinity gives information in real-time about the release of the alkyl radical. Alkoxyamine adaptation for a conditional homolysis through specific glioma proteolysis activity could induce a localized alkyl therapeutic effect with a real-time monitoring. Physiological barriers limit the drug accumulation in the targeted sites. In this study, the intratracheal instillation of nanoparticles can substitute the intravenous administrationincreasing their intratumoral retention time.

Purpose: The objective of this thesis is to evaluate clinical studies that have used oncolytic viruses as treatment and to compare their treatment-outcomes on patients with malignant glioma. Method: This thesis is a systematic literature review where PubMed has been used as the database for data collection. Two searches were done using the search phrases oncolytic virus AND Glioma and oncolytic virus AND brain tumor. Several of the articles showed up multiple times in different searches. After having applied the inclusion criteria, ten of the seventeen articles were removed. Remaining were seven articles used for the thesis. Results: The study conducted by Forsythe et al., using reovirus showed the median overall survival (OS) to be 21 weeks and the median time to progression (TTP) was 4.3 weeks. The study conducted by Kicielinski et al., using REOLYSIN showed the median OS to be 140 days. Median TTP was 61 days. The study conducted by Geletneky et al., 2017 was the first dose-escalating clinical trial for the use of H-1 parvovirus. The median TTP was 111 days and the median OS was 464 days. The study conducted by Lang et al., DNX-2401 was used and in group A the median OS time was 9.5 months. In group B the median OS in the group was 13 months. In another example of an oncolytic adenovirus is ONYX-015, the median TTP after treatment for all patients was 46 days. The median OS for patients diagnosed with glioblastoma multiforme was 4.9 months and for patients with anaplastic astrocytoma and anaplastic oligodendroglioma was 11.3 months across. In a study conducted by Freeman et al. using newcastle disease virus, the OS ranged from 3-66 weeks from the start of treatment and TTP ranged from 2-53 weeks. The study conducted by Markert et al., the median OS from treatment with G207 was 7.5 months. The median TTP was around 2.5 months. Conclusion: Oncolytic viruses are promising agents for treatment against malignant gliomas. No definite outcomes of the treatment could be concluded, however, the median survival was extended in certain cases. The patients tolerated the oncolytic viruses well with no adverse effects correlated with the treatments. There are currently more virus vectors being tested as new developments are needed in this field.

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Though most primary brain gliomas present as a single mass lesion in the brain, this potential diagnosis must be considered in the differential diagnosis when faced with a case of multifocal brain mass lesions. Among the most common brain tumors in humans, glioblastomas can be classified into four classes, one of which consists of anaplastic astrocytomas (AA). Due to its significant malignant potential, a prompt stereotactic brain biopsy should be considered to allow for early diagnosis. Karyotypic analysis of the specimen may allow for the discovery of 1p12q and IDH132 gene mutations. This knowledge can be used to best determine prognosis and guide therapy.

OBJECTIVE: The overarching goal of this study was to examine the immunostimulatory potential of oHSV-1 rQNestin34.5v2 in syngeneic murine GBM models, perform in vitro screens for upregulation of immune checkpoint molecules in infected glioma cells, and evaluate the antitumor activity of the most promising combination immunovirotherapies. METHODS: The oncolytic activity of HSV-1 rQNestin34.5 was evaluated in CT-2A and GL261 syngeneic murine glioma models. Immunoassays were conducted to assess secretion of damage associated molecular patterns including ATP, HMGB1, Calreticulin, HSP70 and other proinflammatory mediators by infected glioma cells. In vitro screens for expression of inhibitory ligands by glioma cells following HSV-1 rQNestin34.5v2 infection at various doses were analyzed by flow cytometry. Intratumoral HSV-1 rQNestin34.5v2 administration and/or intraperitoneal anti-TIGIT (clone 1B4)/anti-NK1.1 treatments were performed in C57BL/6 mice bearing orthotopic CT-2A glioma to determine effect on overall survival. RESULTS: HSV-1 rQNestin34.5v2 exhibited greater capacity to infect CT-2A and minimal capacity to infect GL261 cells suggesting differences in permissiveness in HSV- 1 replication between the two GBM models. Infection stimulated immunogenic cell death as evidenced by surface expression of calreticulin and HSP70 and elevated extracellular release of ATP and HMGB1 in the GL261 model. CD155 and CD112 (both ligands of TIGIT) as well as PD-L1 were significantly highly expressed in glioma cells. TIGIT was found to be overexpressed in tumor infiltrating NK, CD4 and CD8 T cells suggesting systemic therapy with TIGIT blockade antibodies could have therapeutic utility in combination with HSV-1 rQNestin34.5v2 in GBM. Benefit in overall survival was not observed by anti-TIGIT monotherapy, and combination treatment with HSV-1 rQNestin34.5v2 exhibited modest therapeutic effect with a cure rate 25% in mice bearing intracranial CT-2A tumors. Depletion of NK cells prior to HSV-1 rQNestin34.5v2 administration attenuated brain edema and synergized with rQNestin34.5v2 virotherapy. CONCLUSION: Our findings show that the combination of HSV-1 rQNestin34.5v2 virotherapy with anti-TIGIT checkpoint blockade immunotherapy and/or NK cell inhibition represents a promising strategy to overcome primary resistance to immune checkpoint inhibitors in GBM. / 2025-02-03T00:00:00Z

Gliomas are aggressive glial cell tumors that are nearly impossible to treat successfully, yielding strikingly low survival rates for patients. Glioblastomas, the most severe type of gliomas, have even poorer prognoses. In the past decade, new literature has shown that H19, a long non-coding RNA (lncRNA), is not only highly expressed in human gliomas, but that it plays several important roles in glioma progression and can even impede certain treatment measures. H19 directly and indirectly promotes several features of glioma cells including their survival, growth, migration, invasion, metastasis – essentially every stage of glioma development – and even stemness. Simply knocking down H19, in vitro, hampered every single one of these features to some degree. High H19 levels have also been linked to a lack of response to temozolomide and radiation treatments, two of the main therapeutic methods currently used to target gliomas. In vivo observations also followed this pattern of high H19 levels correlating with glioma tumorigenicity. So far, due to the accumulation of such findings, H19 has already become valued as both a prognostic and theragnostic marker. However, having seen how damaging H19 knockdown is to gliomas, there is no reason the role of H19 should be limited to that of an indicator; rather, the proto-oncogenic lncRNA should be viewed as a potential therapeutic target. Moreover, given that high H19 expression is an attribute unique to the human embryo stage, any instances of upregulation are typically oncogenic in nature, making H19 an ideal target for cancer therapy. Thus, targeting H19 in glioma patients should be integrated into existing treatment plans as this will obstruct glioma tumorigenesis, improve responsiveness to other therapies, and is not likely to impede normal biological functions.

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No description available.

c-Cbl functions as a multifunctional adaptor and an E3 ubiquitin protein ligase. Several studies have shown that c-Cbl is involved in cytoskeleton-mediated events, but the molecular mechanisms linking c-Cbl to cytoskeletal rearrangements remain to be elucidated. Our previous results indicated that c-Cbl facilitates spreading and migration of v-Abl-transformed NIH 3T3 fibroblasts and suggested that small GTPases play important roles in the cytoskeletal effects of c-Cbl in this system. To elucidate the individual contributions of small GTPases to these effects, we assessed the roles of endogenous Rac1, RhoA and Rap1 in the c-Cbl-dependent spreading and migration of v-Abl-transformed fibroblasts overexpressing c-Cbl, using RNAi. Furthermore, since it has been shown that Rap1 can act as an upstream regulator of Rac1 in inducing cell spreading, we analyzed the interplay between Rap1 and Rac1 in the signaling pathways connecting c-Cbl to the cytoskeletal events. Our results indicate that Rac1 is essential for cell migration and spreading, whereas activation of RhoA exerts a negative effect. We have also shown that Rap1 is essential for cell spreading, although not for migration in our experimental system. Furthermore, we provide evidence that Rap1 is located upstream of Rac1 in one of the signaling pathways that regulate c-Cbl-facilitated cell spreading. Overall, our findings are consistent with the model describing the connection of c-Cbl to the cytoskeletal rearrangements via two pathways, one of which is mediated by PI3K and Rac1, and the other, by CrkL/C3G, Rap1 and Rac1. A major biological feature of glioma is the ability to invade normal brain tissue. The molecular mechanisms of glioma invasion are involved in multiple biological processes which are primarily associated with cytoskeleton-mediated events including adhesion, migration, degradation of extra cellular matrix (ECM). Biological functions of c-Cbl in glioma have not been elucidated. In this study, we examined biological roles of c-Cbl using RNAi-mediated depletion of endogenous c-Cbl and stably c-Cbl expressing glioma cells generated by lentiviral transduction and showed that c-Cbl increases invasion through degradation of ECM by upregulation of MMP2 but not through migration, adhesion, or growth of SNB19, a grade IV glioblastoma cell line. / Microbiology and Immunology / Accompanied by two .avi videos

Gliomas are the most common and difficult to treat tumors of the central nervous system. Current treatments often fail to slow progression of disease due to the high invasive nature of glioma leading to a high percentage of recurrence. Our previous studies have demonstrated that the levels of alpha; 9 beta; 1 integrin found on high grade glioma were significantly increased in comparison to normal brain tissue where the levels were negligible. We also found that interaction between alpha; 9 beta; 1 integrin and nerve growth factor (NGF) plays a major role in progression of experimental tumor. Another receptor for NGF the common neurotrophin receptor p75NTR is also overexpressed in high grade glioma. p75NTR forms a high affinity complex with the specific NGF receptor, TrkA leading to an increase in cell proliferation and survival. In the absence of an association, p75NTR is involved in transferring pro-apoptotic signals through the JNK pathway. We have found that the α 9 integrin subunit of α 9 β 1 forms a stable, cation independent complex with p75NTR on the cell membrane of glioma both in vitro using glioma derived immortalized cells lines and in vivo using glioma tissue. The co-expression of p75NTR with α 9 β 1 integrin led to optimization of integrin-dependent cellular activities such as cell survival, proliferation, and migration. Co-expression of p75NTR was also required for implanted glioma cells to migrate in a glioma-like perivascular manner away from the site of implantation as was seen in the in vivo quail chorioallantoic membrane assay. / Biology