| Research Abstract |
Suppression of angiogenesis is of importance in cancer treatment. The molecular basis of human endothelial cell motility is obviously highly complex and is believed to be controlled by a number of molecular systems, including cell adhesion molecules, their receptors, cytoskeletal components, a junctional unit connecting the cytoskeletal components and membrane receptors, and various peptide growth factors. The aims of this study were to systematically investigate the possible involvement of proteins at the human endothelial cell surface in controlling cell motility and further identify the cell surface molecules involved in the angiogenesis. The present study utilized an approach based on the selection of HUVEC, which showed motility. We have addressed this study using functional monoclonal antibodies (MAbs), which inhibit HUVEC motility, as probes. The monoclonal antibody HM7-3 was established after immunization of mice with HUVEC, and was selected on the basis of its ability to inhibit HUVEC migration in a matrigel transwell penetration assay. HM7-3 inhibited angiogenesis using eggs and cornea of rats. cDNA cloning revealed that HM7-3 recognizes a new specific protein structure and we named this protein Angiogenesis Inhibiting Protein (AIP). However, the extent of suppression of angiogenesis is not directly related to the level of AIP expression. As AIP has several N-glycosylation sites, the function of AIP may be, in general, highly controlled by N-glycosylation. De-N-glycosylation of AIP results in the loss of functions. The further examination will be necessary for the analysis of the mechanism of AIP.
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