Format

Send to

Choose Destination
J Cell Commun Signal. 2018 Mar;12(1):157-170. doi: 10.1007/s12079-017-0428-0. Epub 2017 Nov 29.

A function-blocking CD47 antibody modulates extracellular vesicle-mediated intercellular signaling between breast carcinoma cells and endothelial cells.

Author information

1
Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Building 10 Room 2S235, 10 Center Drive MSC1500, Bethesda, MD, 20892-1500, USA.
2
Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
3
Inflammation Biology Section, Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20982, USA.
4
Section of Intercellular Interactions, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20982, USA.
5
Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Building 10 Room 2S235, 10 Center Drive MSC1500, Bethesda, MD, 20892-1500, USA. droberts@mail.nih.gov.

Abstract

Tumor cells release extracellular vesicles (EVs) into the tumor microenvironment that may facilitate malignant progression and metastasis. Breast carcinoma EVs express high levels of the thrombospondin-1 and signal regulatory protein-α receptor CD47, which is the target of several experimental therapeutics currently in clinical trials. We analyzed changes in gene expression and function in human umbilical vein endothelial cells (HUVEC) induced by treatment with EVs derived from breast carcinoma cells and the effects of the function-blocking CD47 antibody B6H12 on the resulting intercellular communication. CD47+ EVs exhibited greater uptake by HUVEC compared to CD47- EVs, but the CD47 antibody did not inhibit their uptake. Global and targeted analyses of transcripts demonstrated that treatment of HUVEC with EVs derived from MDA-MB-231 breast carcinomas cells altered pathways associated with tumor necrosis factor-α signaling, angiogenesis, lymphangiogenesis, endothelial-mesenchymal transition, and extracellular matrix. EVs from triple-negative MDA-MB-231 cells were more active than EVs from less metastatic breast carcinoma cell lines. Treatment with MDA-MB-231 EVs down-regulated VEGFR2 mRNA expression and tyrosine phosphorylation while enhancing phosphorylation of the tyrosine phosphatase SHP2. VEGFR2 expression and phosphorylation in HUVEC was further inhibited by the CD47 antibody. Consistent with the observed changes in endothelial-mesenchymal transition genes and SHP2, treatment with MDA-MB-231-derived EVs decreased Zeb1 protein levels in HUVEC, whereas the CD47 antibody increased Zeb1 levels. The induction of E-selectin and other known targets of tumor necrosis factor-α signaling by EVs was also enhanced by the CD47 antibody, and E-selectin was the most up-regulated transcript following CD47 antibody treatment alone. These studies reveal several mechanisms by which therapeutics targeting CD47 could modulate tumor growth by altering the cross talk between cancer-derived EVs and nonmalignant cells in the tumor stroma.

KEYWORDS:

Angiogenesis; CD47; Endothelial-mesenchymal transition; Extracellular vesicles; Tumor microenvironment; Tumor necrosis factor-α

Supplemental Content

Full text links

Icon for Springer Icon for PubMed Central
Loading ...
Support Center