Increased expression of H/T-cadherin in tumor-penetrating blood vessels

Neovascularization is a prerequisite for tumor growth. Thus, selective destruction of the tumor vasculature should prevent tumor expansion. We have established a method to identify proteins that are specifically expressed on the surface of endothelial cells in tumors. CD31-positive endothelial cells were isolated from Lewis lung carcinoma lung metastases as well as from normal lung tissue. cDNAs derived from these cells were subjected to a subtractive hybridization procedure, and cDNAs overrepresented in tumor-derived endothelial cells were isolated; those encoding surface proteins were selected using a signal sequence trap assay. One isolated cDNA encoded H/T-cadherin. In this report, we show that mouse H/T-cadherin is overexpressed on endothelial cells of several tumors, whereas it is expressed only on a subset of endothelial cells in healthy organs. On the basis of the expression of H/T-cadherin in lung metastases of different tumors, we suggest that different tumors can have a differential influence on the expression of endothelial cell surface proteins.