Vascular leukocytes contribute to tumor vascularization

• Published in: Blood Vol. 105; no. 2; pp. 679 - 681
• Main Authors: Conejo-Garcia, Jose R., Buckanovich, Ronald J., Benencia, Fabian, Courreges, Maria C., Rubin, Stephen C., Carroll, Richard G., Coukos, George
• Format: Journal Article
• Language: English
• Published: Washington, DC Elsevier Inc 15.01.2005; The Americain Society of Hematology
• Subjects: Animals; Antigens, CD; Biological and medical sciences; Blood vessels and receptors; Cadherins - metabolism; Female; Fundamental and applied biological sciences. Psychology; Humans; Leukocyte Common Antigens - metabolism; Leukocytes - cytology; Leukocytes - physiology; Mice; Mice, Inbred BALB C; Mice, SCID; Neovascularization, Pathologic - immunology; Ovarian Neoplasms - blood supply; Ovarian Neoplasms - immunology; Stem Cells - cytology; Stem Cells - physiology; Vertebrates: cardiovascular system; Human; Angiogenesis; Endothelial cell; Postnatal; Leukocyte; Stem cell; Blood vessel; Hematopoietic cell; Development; Tumor; Circulatory system; Vascularization
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2004-05-1906

There is no proof that hematopoietic cells contribute significantly to vasculogenesis in postnatal life. Here we report a novel leukocyte subset within ovarian carcinoma that coexpresses endothelial and dendritic cell markers. Fluorescence-activated cell sorter (FACS) analysis identified a high frequency of VE-cadherin+ CD45+ leukocytes (39% of host cells) in 10 of 10 solid tumors evaluated. This population represented less than 1% of nontumor cells in ascites and peripheral blood. At the protein level, more than 86% of these cells expressed the endothelial markers P1H12, CD34, and CD31 and leukocyte markers CD11c and major histocompatibility complex (MHC) class II. At the mRNA level, we detected TEM1, TEM7, and Thy-1, specific markers of angiogenic endothelium. Finally, this population has the capacity to generate functional blood vessels in vivo. Because of its mixed phenotype, we named this population vascular leukocytes (VLCs). Our data provide an important link between hematopoietic endothelial precursors and vascular development in postnatal life and a possible novel therapeutic target.