Influence of angiogenesis inhibitors on endothelial cell morphology in vitro.
Human umbilical vein endothelial cells (HUVEC) propagated in co-culture with fibroblasts form capillary-like networks of tubes. Here we characterize the morphology and ultrastructure of HUVEC in such co-cultures and investigate the influence of different angiogenesis inhibitors on endothelial cell morphology. Addition of angiogenesis inhibitors to the co-culture disrupted endothelial network formation and influenced endothelial cell morphology in two distinct ways. Instead of characteristic capillary-like networks, the endothelial cell morphology appeared as either short cords or compact cell clusters of variable size. Electron microscopy (EM) showed that in co-culture untreated HUVEC formed capillary-like tubes with lumina and retained important ultrastructural and physiological properties of endothelial cells in functional vessels as they contained both Weibel-Palade bodies and transport vesicles. Immuno-EM showed that the endothelial cell marker CD 31 stained endothelial membranes at cell-cell contacts, and at the luminal and abluminal side of the capillary-like tubes, although most abundantly at the luminal membranes. No ultrastructural signs of apoptosis were seen in HUVEC in inhibitor-treated co-cultures. Our results demonstrate that treatment with levamisole or anti-VEGF inhibits endothelial cell differentiation into tubes or instead induces formation of compact endothelial cell clusters. Treatment with platelet factor 4, suramin and TNP-470 results in formation of short endothelial cell cords. We discuss the implications of these findings.
Friis
Tina
T
Department of Research and Development, Division of Plasma Products, Statens Serum Institut, Copenhagen, Denmark.
Hansen
Alastair B
AB
Houen
Gunnar
G
Engel
Anne-Marie
AM
D020533:Angiogenesis Inhibitors / Q000494:pharmacology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects* / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron
D020533:Angiogenesis Inhibitors