ALPHA-V INTEGRINS AS RECEPTORS FOR TUMOR TARGETING BY CIRCULATING LIGANDS

Phage displaying an Arg-Gly-Asp (RGD)-containing peptide with a high a ffinity for av integrins homed to tumors when injected intravenously i nto tumor-bearing mice. A substantially higher amount of av-directed R GD phage than control phage was recovered from malignant melanomas and breast carcinoma. Antibodies detected the av-directed RGD phage in tu mor blood vessels, but not in several normal tissues. These results sh ow that the alpha v integrins present in tumor blood vessels can bind circulating ligands and that RGD peptides selective for these integrin s may be suitable tools in tumor targeting for diagnostic and therapeu tic purposes.