Primary tumor hypoxia recruits CD11b /Ly6Cmed/ Ly6G immune suppressor cells and compromises NK cell cytotoxicity in the premetastatic niche

Abstract

Hypoxia within a tumor acts as a strong selective pressure that promotes angiogenesis, invasion, and metastatic spread. In this study, we used immune competent bone marrow chimeric mice and syngeneic orthotopic mammary cancer models to show that hypoxia in the primary tumor promotes premetastatic niche formation in secondary organs. Injection of mice with cell-free conditioned medium derived from hypoxic mammary tumor cells resulted in increased bone marrow-derived cell infiltration into the lung in the absence of a primary tumor and led to increased metastatic burden in mammary and melanoma experimental metastasis models. By characterizing the composition of infiltrating bone marrow-derived..