Programmed death (PD)‐1/PD‐ligand 1 blockade mediates antiangiogenic effects by tumor‐derived CXCL10/11 as a potential predictive biomarker

Immune checkpoint inhibitor (ICI) programmed death (PD)‐1/PD‐ligand 1 (PD‐L1) blockade has been approved for various cancers. However, the underlying antitumor mechanisms mediated by ICIs and the predictive biomarkers remain unclear. We report the effects of anti‐PD‐L1/PD‐1 Ab in tumor angiogenesis. In syngeneic mouse models, anti‐PD‐L1 Ab inhibited tumor angiogenesis and induces net‐like hypoxia only in ICI‐sensitive cell lines. In tumor tissue and serum of ICI‐sensitive cell line‐bearing mice, interferon‐γ (IFN‐γ) inducible angiostatic chemokines CXCL10/11 were upregulated by PD‐L1 blockade. In vitro, CXCL10/11 gene upregulation by IFN‐γ stimulation in tumor cell lines correlated with the sensitivity of PD‐L1 blockade. The CXCL10/11 receptor CXCR3‐neutralizing Ab or CXCL11 silencing in tumor cells inhibited the antiangiogenic effect of PD‐L1 blockade in vivo. In pretreatment serum of lung carcinoma patients receiving anti‐PD‐1 Ab, the concentration of CXCL10/11 significantly correlated with the clinical outcome. Our results indicate the antiangiogenic function of PD‐1/PD‐L1 blockade and identify tumor‐derived CXCL10/11 as a potential circulating biomarker of therapeutic sensitivity.