AUTOPHAGY CONDITIONS THE IMMUNE RESPONSE TO PANCREATIC TUMORS

PAPADEMETRIO, DL; LOMBARDO, T; COSTANTINO, S; PAGLILLA, N; BLANCO, G; ALVAREZ, E; LEVERMANN, M; MIHALEZ, CY

Mar del Plata

Congreso; LXIII Reunión anual de la sociedad argentina de investigación clínica (SAIC), LXVI Reunión anual de la sociedad argentina de inmunología (SAI), Reunión anual de la sociedad argentina de fisiología (SAFIS).; 2018

Pancreatic ductal adenocarcinoma (PDAC) is characterized by inducing tolerance of the immune system. In this mechanism exosomes participate as intercellular messengers, carrying molecules from the tumor cell to the immune cells. We previously described that autophagy is crucial for PDAC survival and chemoresistance. In this work we investigated the role of autophagy in the composition of tumor exosomes and their impact on the activity of Natural Killer (NK) and Dendritic cells (DC).For that, we performed the experiments using two PDAC cell lines, MIAPaCa-2 and PANC-1, and two inhibitors of autophagy, 3-Methyladenine (3-MA) and Spautin-1 (SP-1).First, we demostrated the presence of exosomes in the supernatant of cells cultured with or without 3-MA or SP-1 by electron microscopy. Besides, the treatment with 3-MA or SP-1 increased CD63 levels observed by western blot.Then, we evaluated NK cytotoxic activity using K562 cell line as target cells. For that we incubated PBMCs with exosomes obtained from supernatant of MIAPaCa-2 and PANC-1 cells treated or not with SP-1, for 2h. K562 cells were stained with CFSE. Co-cultures of PBMCs:K562 in a ratio 50:1 were performed for 4h. Cytotoxicity of NK cells was evaluated by CFSE/PI stain. Exosomes from cell supernatant treated with SP-1 stimulated cytotoxic activity of NK cells (p