E‐selectin targeting to visualize tumorsin vivo

Generally angiogenic factors induce the expression of E‐selectin in vascular endothelial cells in the tumors. In this study, we employed an anti‐E‐selectin monoclonal antibody to target tumors in vivo and evaluated an optical imaging reagent to visualize tumor regions. The anti‐E‐selectin antibody was conjugated on the surface of liposomes, which encapsulated the near‐infrared fluorescent substances Cy3 or Cy5.5. The liposomes efficiently recognized human umbilical vein endothelial cells only when E‐selectin was induced by angiogenic factors such as TNF‐α in vitro. Cy5.5 encapsulated into liposomes that were conjugated with an anti‐E‐selectin antibody successfully visualized Ehrlich ascites tumor cells when transplanted into mice. Thus, E‐selectin targeting with liposomes containing a near‐infrared fluorescent dye was found effective in visualizing tumors in vivo. This strategy should be extremely useful as a method to identify sentinel lymphatic nodes and angiogenic tumors as well as use for drug delivery to tumor cells. Copyright © 2010 John Wiley & Sons, Ltd.