Integrin αV (IαV) and the urokinase-type plasminogen activator receptor (uPAR) are key mediators of tumor malignancy in Glioblastoma. This study aims to characterize IαV/uPAR interaction in GBM and investigate the role played by glycans in this scenario. Protein expression and interaction were confirmed via confocal microscopy and co-immunoprecipitation. The role of N-glycosylation was evaluated using Swainsonine (SW) and PNGase F. IαV glycoproteomic analysis was performed by mass spectrometry. Sialic acids and glycan structures in IαV/uPAR interaction were tested using neuraminidase A (NeuA) and lectin interference assays, respectively. Protein expression and their interaction were detected in GBM cells, but not in low-grade glioma cells, even in cells transfected to overexpress uPAR. SW, PNGase, and NeuA treatments significantly reduced IαV/uPAR interaction. Also, lectin interference assays indicated that β1-6 branched glycans play a crucial role in this interaction. Analysis of the IαV glycosylation profile revealed the presence of complex and hybrid N-glycans in GBM, while only oligomannose N-glycans were identified in low-grade glioma. N-glycosylation inhibition and sialic acid removal reduced AKT phosphorylation. Our findings demonstrate, for the first time, the interaction between IαV and uPAR in GBM cells, highlighting the essential role of N-glycosylation, particularly β1-6 branched glycans and sialic acids.

Modulation of the immune system has been demonstrated as a powerful approach to treating cancer. Immunotherapies are generally classified as active or passive according to their ability to trigger the immune system. During the last decades, information regarding the relevance of aberrant glycosylation as a major player in tumour biology encouraged expectations for the development of new therapeutic strategies directed at glycans. Several tumour-associated carbohydrate antigens (TACAs) have been identified and validated as suitable immunotherapeutic targets, leading to promising therapeutic developments. It is known that TACAs are poorly immunogenic since they are unable to trigger a proper immune response. Given that they are not presented by major histocompatibility complex (MHC) molecules and that they induce immune tolerance, the development of active immunotherapeutic strategies against TACAs is a real challenge. However, antitumor strategies based on mimetics of TACAs have been developed and show promising results. Active immunotherapies based on TACAs mimicry can currently be grouped into strategies based on the use of mimetic peptides and anti-idiotype (Id) antibodies. In this review, we discussed the scientific basis on which these strategies are based and the available therapeutic options that have shown the best results in preclinical studies and in clinical practice.