EBV infection in epithelial malignancies induces resistance to antitumor natural killer cells via F3-mediated platelet aggregation.

Nasopharyngeal carcinoma (NPC) and Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) are two major EBV-associated epithelial malignancies, both of which are characterized by the infiltration of a large number of lymphocytes, including natural killer (NK) cells. Although NK cells can prevent the development of EBV-associated epithelial malignancies, EBV-infected tumor cells often develop resistance to surveillance by NK cells. Elucidating the interactions between NK cells and EBV-infected tumor cells will facilitate the development of more effective NK-mediated therapies for treating EBV-associated malignancies. Here we investigated the cytotoxic function of NK cells in EBV-associated epithelial malignancies and discovered that EBV infection-induced upregulation of F3 expression correlates with NK cell dysfunction in NPC and EBVaGC. The subsequent inhibitory effect of F3-mediated platelet aggregation on NK cell function was verified in vitro and in vivo. Mechanistically, EBV latent membrane protein 2A (LMP2A) mediated upregulation of F3 through the PI3K/AKT signaling pathway. In an NPC xenograft mouse model, inhibition of F3 restored the antitumor function of NK cells and showed therapeutic efficacy when administered with NK cell transfer. Based on these findings, EBV infection induces F3-mediated platelet aggregation that inhibits the antitumor function of NK cells, providing a rationale for developing and combining NK cell-based therapies with F3 inhibitors to treat EBV-associated epithelial malignancies.