A few years ago Renata Pasqualini and Erkki Ruoslahti developed an in vivo selection method to identify peptides that target specific vascular beds following intravenous administration of random peptide phage-display libraries in mice. In the February issue of
They injected a large-scale, random peptide library into a terminally ill patient and collected tissue samples 15 minutes post-infusion. They recovered phage from different organs and carried out a high-throughput analysis of over 4,000 phage inserts. Comparison of the selected tripeptide motif frequencies revealed a non-random, tissue-specific distribution. They then used a phage-overlay histological assay to validate peptide sequences specific for prostate or skin tissues.
This study represents a first step towards a well-characterized map of the heterogeneity within...