IFN-γ-mediated suppression of ANGPT2-Tie2 in endothelial cells facilitates tumor vascular normalization during immunotherapy.

Introduction: Tumor angiogenesis is a critical biological hallmark of cancer, which involves multiple molecularly regulated signaling pathways, including the angiopoietin (ANGPT)-Tie2 and the vascular endothelial growth factor (VEGF) signaling pathways. Despite initial optimism, targeting tumor angiogenesis in the treatment of lung adenocarcinoma (LUAD) has been unsatisfactory. Currently, monotherapy with PD-1/PD-L1 inhibitors, or their combination with bevacizumab, is considered the standard therapeutic approach for LUAD. Recent studies have shown that immunotherapy suppresses tumor angiogenesis and facilitates vascular normalization. However, whether and how anti-PD-L1 therapy influences tumor vasculature remains unclear. Methods: To investigate the impact of immunotherapy on the vasculature of LUAD, a mouse model of lung adenocarcinoma was established by subcutaneous implantation of Lewis lung carcinoma cells Results: Employing a mouse model of LUAD, we demonstrated that PD-L1 blockade therapy inhibits tumor angiogenesis and normalizes vasculature in an IFN-γ-signaling-dependent manner. Notably, anti-PD-L1 therapy reduced Tie2 and ANGPT2 expression, and these effects were reversed by the JAK1/2 inhibitor. Mechanistically, we demonstrated that IFN-γ inhibited Tie2 and ANGPT2 expression in ECs, and suppressed Discussion: In conclusion, our results revealed a novel mechanism wherein IFN-γ-mediated inhibition of ANGPT2-Tie2 facilitates vascular normalization during immunotherapy in LUAD, which performs an essential function in the antitumor efficacy of immunotherapy.