Hypoxia-Inducible Factor α Subunits Regulate Tie2-Expressing Macrophages That Influence Tumor Oxygen and Perfusion in Murine Breast Cancer.

Hypoxia-Inducible Factor α Subunits Regulate Tie2-Expressing Macrophages That Influence Tumor Oxygen and Perfusion in Murine Breast Cancer. J Immunol. 2020 Sep 16;: Authors: Steinberger KJ, Forget MA, Bobko AA, Mihalik NE, Gencheva M, Roda JM, Cole SL, Mo X, Hoblitzell EH, Evans R, Gross AC, Moldovan L, Marsh CB, Khramstov VV, Eubank TD Abstract Tie2-expressing monocytes/macrophages (TEMs) are a distinct subset of proangiogenic monocytes selectively recruited to tumors in breast cancer. Because of the hypoxic nature of solid tumors, we investigated if oxygen, via hypoxia-inducible transcription factors HIF-1α and HIF-2α, regulates TEM function in the hypoxic tumor microenvironment. We orthotopically implanted PyMT breast tumor cells into the mammary fat pads of syngeneic LysMcre, HIF-1α fl/fl /LysMcre, or HIF-2α fl/fl /LysMcre mice and evaluated the tumor TEM population. There was no difference in the percentage of tumor macrophages among the mouse groups. In contrast, HIF-1α fl/fl /LysMcre mice had a significantly smaller percentage of tumor TEMs compared with control and HIF-2α fl/fl /LysMcre mice. Proangiogenic TEMs in macrophage HIF-2α-deficient tumors presented significantly more CD31+ microvessel density but exacerbated hypoxia and tissue necrosis. Reduced numbers of proangiogenic TEMs in macrophage HIF-1α-deficient tumors presented significantly less microvessel density but tumor vessels that were more functional as l...
Source: Journal of Immunology - Category: Allergy & Immunology Authors: Tags: J Immunol Source Type: research