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Contributions négatives et positives de la galectine-9 au développement tumoral : étude dans des modèles tumoraux murins syngéniques

Abstract : Like other galectins, galectin-9 (gal-9) is an animal lectin which interacts with a defined subgroup of glycans carried by glycoproteins or glycolipids. Gal-9 associated with cells performs multiple functions in the cytoplasm, in the nucleus and at the surface of the plasma membrane. Some publications suggest that intracellular gal-9 inhibits the mobility of malignant cells and exerts an anti-metastatic effect. In addition, gal-9 can be secreted into the extracellular medium where it behaves like a cytokine with mainly immunosuppressive effects. These effects have been demonstrated in the context of human tumors and in mouse tumor models. However, so far there was no murine tumor model available to assess the pro-tumor or anti-tumor effet of gal-9 independently of gal-9 produced by infiltrating cells. To address this issue, we derived isogenic clones invalidated or not for gal-9 from 2 murine tumoral lines : CT26 (BABL/c genetic background) and MB49 (C57BL/6 genetic background), using CRISPR/Cas9 technology. In the case of the MB49 line, we were able to demonstrate a remarkable phenotype in vivo. During serial transplantations, we saw, for tumors derived from invalidated clones, a dramatic reduction in tumor growth after 3 or 4 passages in syngenic mice but not in immunodeficient mice. The emergence of the immune response responsible for this arrest of tumor growth was investigated by immunohistochemistry, multiplex cytokine assay in tumor extracts and transcriptome analysis by RNAseq. Increased intra-tumor production of interferon-γ, CXCL9 and Il-6 appears to play an important role in enhancing the immune response against KO-gal-9 tumors.
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https://tel.archives-ouvertes.fr/tel-03298760
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Submitted on : Saturday, July 24, 2021 - 1:01:13 AM
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  • HAL Id : tel-03298760, version 1

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Valentin Baloche. Contributions négatives et positives de la galectine-9 au développement tumoral : étude dans des modèles tumoraux murins syngéniques. Cancer. Université Paris-Saclay, 2020. Français. ⟨NNT : 2020UPASS117⟩. ⟨tel-03298760⟩

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