BMEC-1 - A HUMAN BONE-MARROW MICROVASCULAR ENDOTHELIAL-CELL LINE WITHPRIMARY-CELL CHARACTERISTICS

Bone marrow microvascular endothelial cells (BMEC) are a functional co mponent of the bone marrow stroma and have been shown to release hemat opoietic regulatory factors as well as to selectively adhere and suppo rt the proliferation and differentiation of CD34(+) hematopoietic prog enitors. An early passage of these cells was immortalized by transfect ion with a vector (pSVT) encoding the large T antigen of SV40. The tra nsformed cell line (CDC/CU.BMEC-1) expresses the SV40 transcript, reta ins the primary cell expression of Ulex europeaus and vWF/ FVIII, and incorporates acetylated low-density lipoprotein. In addition, BMEC-1 m irrors the phenotype of the primary cells with only a few exceptions. Both cell populations express the cellular adhesion molecules ICAM-1 a nd PECAM and also VCAM-1 and ELAM-1 after upregulation by tumor necros is factor-alpha. The fibronectin receptor, hyaluronate receptor, colla gen receptor, integrins VLA-alpha 3, VLA-alpha 4, and beta 4, endoglin , collagen IV, CD58, and CD61 are also expressed. The only differences are that BMEC-1 expresses higher levels of ICAM-1, CD58, CD34, CD36, and c-kit than the primary cells. The supernatants of primary cell and BMEC-1 contain stem cell factor, interleukin-6 (IL-6), granulocyte-ma crophage colony-stimulating factor (GM-CSF), IL-1 alpha, IL-11, and G- CSF. The functional significance of these hematopoietic cytokines was demonstrated in transwell cultures. Both cell populations supported th e expansion of progeny from CD34(+) cell-enriched cord blood mononucle ar cells suspended in the upper chamber. These characteristics, plus t he fact that BMEC-1 can be maintained independently of exogenous growt h factors and exhibit contact inhibition, indicate that this cell line can be used to further define the role of BMEC in hematopoiesis. (C) 1996 Academic Press, Inc.