THE INTERACTION OF INTEGRIN ALPHA V (IΑV) WITH THE UROKINASE-TYPE PLASMINOGEN ACTIVATOR RECEPTOR (UPAR), AND THE SUBSEQUENT AKT SIGNALING IN GLIOBLASTOMA, IS DEPENDENT ON THE PRESENCE OF COMPLEX AND HYBRID N-GLYCOSYLATION

GRETEL MAGALÍ FERREIRA; CYNTHIA ANTONELLA GULINO; SELENE ROJO; JEREMÍAS OMAR CASTILLO; VALERIA INÉS SEGATORI; MARIANO ROLANDO GABRI

Mar del Plata

Congreso; LXVIII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2023

Sociedad Argentina de Investigación Clínica

Integrin alpha V (I𝛼V) and urokinase-type plasminogen activatorreceptor (uPAR) are described as tumor-associated proteins in glioblastoma (GBM), being both associated with poor survival as wellas resistance to treatment. uPAR participates in the modulation ofcell behavior by binding to integrins and receptor tyrosine kinaseson the plasma membrane to form complexes that actively participate in cell signaling. While their interaction has been documentedin other malignancies, it remains uncharacterized in GBM, the mostcommon and aggressive primary brain tumor. Both proteins haveN-glycosylation sites that can potentially be involved in the interaction with other proteins. The aim of this work was to analyze therole of N-glycosylation in the interaction between I𝛼V and uPAR,and its impact on AKT signaling pathways. By employing IαV immunoprecipitation (IP) and MS/MS analysis, an oligomannose N-glycan profile was shown in low-grade glioma cells, while high-gradecells primarily exhibited complex and hybrid N-glycan structures andabundant sialic acids. uPAR expression was only detected by western blot in the high-grade cell line A172, and co-IP confirmed its interaction with IαV. Same result was observed by confocal microscopy (CM), quantified by Pearson’s coefficient analysis. Interestingly,this interaction was abrogated by treatment with the N-glycosylationinhibitor Swainsonine (SWN), and PHA-L lectin preincubation, whichrecognizes complex and hybrid N-glycans by both co-IP and CM(***p< 0.001). In contrast, this interaction was not interfered whencells were preincubated with ConA, a lectin that recognizes oligomannose N-glycans. SWN treatment resulted in a down-modulationof the AKT signaling pathway, as evidenced by a reduction in thepAKT/AKT ratio. In conclusion, our results suggest that complex andhybrid N-glycans are involved in the interaction between I𝛼V anduPAR in GBM modulating its downstream AKT signaling.