1- Targeting immunovascular interactions to limit immunosuppression and vessel dysmorphia Glioma growth and progression are characterized by abundant development of aberrant and poorly functional blood vessels, with adverse consequences on the efficacy of drug delivery. The mechanisms underlying this vascular dysmorphia during tumor progression are poorly understood. Our longitudinal studies have identified a shift from functional angiogenesis, forming a highly branched vascular network during initial tumor growth, radically evolving towards vascular expansion linked to functional defects (leakage, loss of vascular lumen) in advanced stages of tumor growth (Mathivet et al., 2017). This transition of the vascular phenotype was accompanied by the recruitment of cytotoxic macrophages in the early stages, followed by an in situ polarization switch into immunosuppressive macrophages producing VEGF-A and moving towards perivascular areas. Targeting macrophages restores vascular structure and function, potentiating the effects of chemotherapy (Mathivet et al. 2017). Also, fine targeting of immunosuppressive repolarization of macrophages promotes the efficacy of conventional immunotherapies (Geraldo et al., 2021). This is why we are studying new molecular targets, in particular axon guidance molecules, to i) limit macrophage recruitment in the tumor microenvironment, and/or ii) limit their repolarization into immunosuppressive macrophages in order to potentiate chemotherapeutic and immunotherapeutic treatments. Fundings: ARC, Ligue contre le cancer ,ARTC, Région Nouvelle Aquitaine   2- Role of Phosphatases in Normal and Tumor Angiogenesis This project is a collaboration between the Tremblay Laboratory (Goodman Cancer Center, Mc Gill University), the team of Barbara Garmy-Susini (Institute of Metabolic and Cardiovascular Diseases, UMR 1297 University Toulouse III – Paul Sabatier) and our team. Protein tyrosine phosphatases are essential modulators of angiogenesis and have been identified as new therapeutic targets in cancer and angiogenesis. We have demonstrated that the expression of the atypical Phosphatase of Regenerative Liver 2 (PRL2) in endothelial promotes angiogenesis by increasing endothelial cell migration and the VEGF-A, DLL-4/NOTCH-1 signaling pathway (Poulet et al., 2020). Our current project aims to fully elucidate the role of PRLs in both neo-angiogenesis, lymphangiogenesis and tumor development. We will focus our attention on the signaling pathways controlled by PRLs in blood and lymphatic endothelial cells and whether the interaction with the metal transporter CNNM2 and 3 is involved, since PRLs act as a magnesium sensor. We will also investigate the role of stroma derived-PRL on tumor development and metastatic spread through both the blood and the lymphatic vasculature. Fundings: INCA, Ligue contre le cancer Nouvelle Aquitaine   3- 3D models of functional vessels: vesseloïd We have, in collaboration with the BioImaging & OptoFluidics Lab (UMR CNRS 5298 Institut d’Optique d’Aquitaine), develop a one-step strategy using a microfluidic coextrusion device to produce mature functional blood vessels. This “vesseloids” is created with alginate hydrogel tube internally coated with extracellular matrix to direct the self-assembly of a mixture of endothelial cells (ECs) and smooth muscle cells (SMCs). The resulting structure, with a lumen formed by ECs surrounded by layers of SMCs, shows properties of functional vessels like quiescence, perfusability, and contractility in response to vasoconstrictor agents (Andrique et al., 2019). We will further develop and use this original model to understand the complexity of blood and lymphatic vessels. Since blood vessels are in first line when an inflammatory process, due to infection, injury, or auto-immune disease, is triggered, we will focus on the development of an inflamed 3D vessel model used to explore vessel inflammation and test the effect of pharmacological modulators and drugs. This project include the investigation of the effect of COVID-19 on blood vessels. Fundings: ANR

 1– Glioblastoma metabolic adaptation to the tumor microenvironment Major characteristics of glioblastoma are their high intra-tumor heterogeneity and their ability to adapt to harsh conditions found in the tumor microenvironment. Among the cellular processes used by cancer cells, autophagy may play an important role in the adaptation to the stress conditions found in the tumor microenvironment. In addition to the non-selective autophagy, specific forms of autophagy can selectively degrade intracellular components linked with cellular metabolism such as mitochondria and lipid droplets and participates to metabolic adaptation. We have demonstrated, in other cancer models, that autophagy is highly regulated by the presence or absence of metabolic substrates (lactate, fatty acids) in the microenvironment and by non-cancer cells found in the tumor microenvironment (adipocytes) (Brisson et al., 2016, Fontaine et al., 2021 et Bellanger et al., 2021). Therefore, selective, and non-selective forms of autophagy might be central cellular mechanisms of the interactions between cancer cells and the surrounding microenvironment and thus participate in cancer progression. We will investigate the role of different forms of autophagy is glioblastoma, in the context of intra-tumor heterogeneity and metabolic adaptation. 2- Endocannabinoid System in Glioblastoma and Tumor Microenvironment The endocannabinoid system (ECS) plays an important role in the regulation of brain physiology and has been implicated in the progression of glioblastoma. Research suggests that modulation of the ECS, particularly through activation of the cannabinoid receptor type 1 (CB1),  inhibit tumor growth, induce cancer cell death, and reduce invasiveness. In healthy brain tissue, CB1 receptors can also be associated with the mitochondrial membrane (mtCB1) and regulate metabolic processes of neurons and astrocytes, but the role of CB1 in cancer cell metabolism has been little studied. By targeting both CB1 and mtCB1, we aim to exploit the metabolic vulnerabilities of cancer cells while simultaneously targeting the tumor microenvironment. Our research seeks to elucidate how CB1-mediated metabolic regulation can be exploited to develop novel therapies for glioblastoma, offering new hope for improved patient outcomes. 3- Plasticity and resistance of cancer stem cells of glioblastoma Despite the aggressive standard-of-care treatments that combine maximal surgical removal, ionizing radiation (IR), and chemotherapy with temozolomide (TMZ), the survival of GB patients is less than 20 months. The main challenges in the clinical management of GB tumours is their intrinsic resistance to currently applied therapies and thus, the vast majority of tumours are recurring. Tumor cell population heterogeneity, its spatiotemporal dynamic adaptation, and cellular-level phenotypic plasticity are key, interrelated contributors to treatment failure. There is now compelling evidence that intratumoral heterogeneity and tumor relapse are driven by a subset of cells with stem or progenitor cell characteristics, termed glioblastoma stem cells (GSCs). GSCs is a population of self-renewing and tumor initiating stem cells with the functional properties of therapeutic resilience, invasion, metabolic adaptations, proliferation, and angiogenesis. Thus, developing novel strategies to eradicate GB cells that exhibit the stem-like feature may represent a promising approach to fight brain cancer. Therefore, we employ state of art-techniques including genome-wide and focused genetic screens, pharmacological screens, proteomic and transcriptomic analysis, patient derived and murine models of glioblastoma to unravel the mechanisms that control the fate, tumorigenesis and resistance of GSCs to current standard of care. These studies will lead to new therapeutic avenues and can pave the way for future clinical trials for better treatment of these deadly tumors.  4-IDH mutated gliomas  IDH-1 mutated gliomas are characterized by a less aggressive biological behaviour, a clinical prognosis less influenced by tumor grade, and include diffuse low grade and intermediate grade gliomas, recently defined as Lower Grade Gliomas (LGGs). This project focuses on LGGs and how to integrate imaging and molecular heterogeneity into a tool to be used in the routine clinical practice for easily predicting LGGs progression. Predicting the prognosis using such high dimensional and heterogeneous data required specific approaches. A predictive model for patient stratification and prediction at onset of diagnosis is the ultimate deliverable that should improve the clinical management of patients. Additional results should be provided by the multilevel approach leading to a better understanding of the disease.