Targeting Urothelium: Ex Vivo Assay Standardization and Selection of Internalizing Ligands

ABSTRACTPurpose: With the goal of targeting the human bladder using phage display technology we designed and tested a tissue binding assay on intact urothelium ex vivo. This approach may form the molecular basis for clinical development of peptide or peptidomimetic guided intravesical compounds.Materials and Methods: We screened 2 phage display random peptide libraries on human urothelium. Select peptides were tested for their binding ability to human urothelium, 2 human transitional cell carcinoma cell lines and a nontransitional cell carcinoma cell line. Next we standardized an ex vivo binding assay, validated binding of selected phage to whole urothelium, and evaluated whether receptor mediated internalization into urothelium derived cells occurred. Finally we tested if the presence of the glycosaminoglycan layer had any effect on the binding of the urothelium targeted phage.Results: Phage selected and recovered in the screening were isolated and sequenced. Displayed peptide sequences were searched aga...