The role of galectin-1 in macrophage accumulation, phenotype and function in high-grade gliomas.

High-grade gliomas (HGG) are the most common primary tumors in the central nervous system in adults. In spite of multidisciplinary treatment the prognosis remains dismal with a median survival expectancy of 15 months. In search for new treatment strategies, immunotherapy has yielded promising results. However, only a minor subset of HGG patients seems to benefit from active immunotherapy. One of the major factors that limits the efficacy of immunotherapy is the extensive immunosuppressive environment present in HGG patients. Tumor-associated macrophages (TAMs) play an important role in the establishment of such an immunosuppressive environment. TAMs can acquire either antitumoral or protumoral functions depending on the environmental signals to which they are exposed. Macrophages that accumulate in progressing tumors often display multiple tumor-promoting functions. These findings suggest that strategies that can prevent TAM accumulation within the tumor microenvironment or that can stimulate their re-education towards cytotoxic macrophages could have a high therapeutic potential. In this project we want to explore whether galectin-1 (gal-1), a glycan-binding protein that is highly expressed in HGG, is involved in TAM recruitment and polarization. I have previously demonstrated that the targeting of glioma-derived gal-1 significantly reduced the number of TAMs which prolonged tumor-bearing mice survival.