[Targeting--a new way to identify unknown tumor markers in blood vessels]

Abstract

The expression of specific molecules on the surface of vascular endothelial cells in tumours might be a key to anticancer therapy with angiostatic drugs. A new method to find these molecules on tumour vessels, targeting, is presented here. Some of these tumour-specific molecules have been identified by means of so called phage libraries. They are gene-manipulated phages, where the surface is decorated with randomly generated short peptides. After intravenous injection a few of the peptides, expressed on the surface of the phage, attach to complementary structures on the endothelial cell, as a ligand attaches to its receptor. Through biopsies and immunohistochemistry the phage can be isolated and identified. The part of the DNA of the phage that codes for the peptide-sequence of importance is sequenced. This seeking for such vessel-addresses can in the future be used for diagnostic purposes and also for local tumour-treatment. It is envisioned that cytotoxic drugs can be coupled to peptides on nanoparticles and act locally, in order to minimize toxic systemic side effects.