The role of VE-cadherin in osteosarcoma cells. Osteosarcoma cells can generate vasculogenic-like, patterned networks to obtain nutrients and oxygen, which mimic some function of endothelial-like cells and facilitate tumor malignant progress. These cells also express vascular endothelial-cadherin (VE-cadherin), which is generally accepted as a strictly endothelial-specific transmembrane protein. However, its role is still relatively obscure in osteosarcoma cells. So we inhibit the VE-cadherin gene expression with siRNA in osteosarcoma cells (MG63), and culture those cells in three-dimensional medium, containing Type I collagen or Matrigel, to observe the role of VE-cadherin. Western blotting analysis show that sequence-specific siRNA can significantly decrease the expression of VE-cadherin in MG63 cell. After knockdown of VE-cadherin, osteosarcoma cells can't induced angiogenic sprout and form osteosarcoma-generated, endothelial-like networks. Our data indicate that VE-cadherin may be a positive and specific regulator not only in angiogenesis, but also in vasculogenic mimicry of osteosarcoma cells. And it can be considered as a new prospective option in the combining treatment of aggressive tumor with highly vascularity, including osteosarcoma.