Apelin inhibition prevents resistance and metastasis associated with anti‐angiogenic therapy

Abstract Angiogenesis is a hallmark of cancer, promoting growth and metastasis. Anti‐angiogenic treatment has limited efficacy due to therapy‐induced blood vessel alterations, often followed by local hypoxia, tumor adaptation, progression, and metastasis. It is therefore paramount to overcome therapy‐induced resistance. We show that Apelin inhibition potently remodels the tumor microenvironment, reducing angiogenesis, and effectively blunting tumor growth. Functionally, targeting Apelin improves vessel function and reduces polymorphonuclear myeloid‐derived suppressor cell infiltration. Importantly, in mammary and lung cancer, Apelin prevents resistance to anti‐angiogenic receptor tyrosine kinase (RTK) inhibitor therapy, reducing growth and angiogenesis in lung and breast cancer models without increased hypoxia in the tumor microenvironment. Apelin blockage also prevents RTK inhibitor‐induced metastases, and high Apelin levels correlate with poor prognosis of anti‐angiogenic therapy patients. These data identify a druggable anti‐angiogenic drug target that reduces tumor blood vessel densities and normalizes the tumor vasculature to decrease metastases.