Integrin-Mediated Macrophage Adhesion Promotes Lymphovascular Dissemination in Breast Cancer.
De Palma, M
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Lymphatic vasculature is crucial for metastasis in triple-negative breast cancer (TNBC); however, cellular and molecular drivers controlling lymphovascular metastasis are poorly understood. We define a macrophage-dependent signaling cascade that facilitates metastasis through lymphovascular remodeling. TNBC cells instigate mRNA changes in macrophages, resulting in β4 integrin-dependent adhesion to the lymphovasculature. β4 integrin retains macrophages proximal to lymphatic endothelial cells (LECs), where release of TGF-β1 drives LEC contraction via RhoA activation. Macrophages promote gross architectural changes to lymphovasculature by increasing dilation, hyperpermeability, and disorganization. TGF-β1 drives β4 integrin clustering at the macrophage plasma membrane, further promoting macrophage adhesion and demonstrating the dual functionality of TGF-β1 signaling in this context. β4 integrin-expressing macrophages were identified in human breast tumors, and a combination of vascular-remodeling macrophage gene signature and TGF-β signaling scores correlates with metastasis. We postulate that future clinical strategies for patients with TNBC should target crosstalk between β4 integrin and TGF-β1.
Mice, Inbred BALB C
Mice, Inbred C57BL
rhoA GTP-Binding Protein
Cell Adhesion Molecules
Gene Expression Regulation, Neoplastic
Transforming Growth Factor beta1
Triple Negative Breast Neoplasms
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Cell reports, 2019, 27 (7), pp. 1967 - 1978.e4