[Targeting of M13 phage particles by human holotransferrin using a chemical coupling strategy]

Background and Objectives: Targeting transgene carriers and vectors to individual cells and tissues is one of the most important goals of gene therapy. Bacteriophages are of appropriate transgene carriers and there are different methods for their targeting to target cells. Present study reports preparation of targeted M13-based bacteriophage particles by a chemical coupling strategy

Materials and Methods: First, the pCMV-Script-GFP construct was produced via in vivo excision protocol from lambda-GFP Phage particles using ExAssist helper phage and XLOLR as specific host. Then, M13 phage particles bearing GFP [M13-GFP] were obtained by single stranded rescue using R408 helper phage. The human holotransferrin molecules were then coupled to the surface of phage particles by reductive amination chemistry. Transferrin molecules bind to the surface of phage particles were studied by phage-ELISA

Results: Phage-ELISA tests showed that holotransferrin molecules were coupled to the surface of M13 phage particles in a correct way and the transferrin-targgeted M13 phage particles were prepared. Further analysis showed that about 485 transferrin molecules coupled per phage particle

Conclusion: The results show that chemical coupling might be considered as a suitable strategy for targeting of M13 particles via coupling of targeting molecules in high density to the phage surface

[Screening phage display library for isolation of human colon cancer cell-binding peptide ligands]

Recently, phage display libraries have received enormous attention for identification and isolation of pharmaceutical molecules with diagnostic and therapeutic properties. Peptide libraries are known as one of the most important and widely used types of phage display libraries. In the current study, we aimed to screen the Ph.D.[TM]-7 phage display peptide library through biopanning for the identification of human colon adenocarcinoma-binding peptide ligands. Three rounds of biopanning were performed on SW480 as the target cell and fibroblast [HF-SF-PI3], AGS, KYSE-30 and Huh-7 as control cells. The displayed peptide-encoding regions in the genome of SW480-binding phages obtained from the final round of panning were amplified by plaque-PCR and subsequently sequenced. Bioinformatic tools were used to determine the sequence of target cell-binding peptides and further characterization of these peptides. Biopanning of the phage library led to the enrichment of several peptides among which the peptide with sequence "HAMRAQP" was the most dominant. Bioinformatic analysis of the isolated peptides indicated that they are not target unrelated peptides [TUP]. The peptides, in particular those with the highest frequency, due to having the capability of specific binding to SW480 cells represent the potential for use in targeting of therapeutic genes and drugs to colon cancer cells