Identification of Novel targeting peptides for PC3 cells by the screening of a phage display peptide library

Prostate cancer after lung cancer is the second cause of cancer-associated death in men. In recent years, targeted therapy of cancer has attracted researchers attention. The targeted therapy lead to decrease in side effects of drugs. Studies have indicated that targeting peptides for cancer cells represent valuable tools for diagnostic and therapeutic. Recently, phage display peptide libraries have been used for identifying targeting peptides to a variety of cancer cells. In the current study, we aim to isolate peptides targeting to PC3 cells (human prostate adenocarcinoma cells). Four rounds of subtractive panning on control cells including 5637 (bladder), Huh-7 (liver) and SW480 (colon) and AGS (stomach) and human fibroblast normal and four rounds of positive panning on PC3 (target cell) were performed. Polyclonal phage ELISA was exploited to evaluate the process of enrichment during biopanning. Subsequently, phage clones were randomly picked out from titer plates, amplified by using plaque-PCR and their genomic DNA was sequenced. Bioinformatic analysis was conducted for further characterization of isolated peptides. Several rounds of panning resulted in the enrichment of some peptides. The results of polyclonal phage ELISA are indicated that the biopanning process was successfully done. Also, in silico analysis has shown the presence of several consensus amino acid motifs in peptides. The peptides identified through biopanning can be considered as a potential specific binders to PC3 cells. Peptides with specificity binding to target cells can be used for targeted gene and drug delivery to malignant tumor cells. Further analysis of these peptides are required to show their capacity for targeted delivery of various genes and drugs into prostate cancer cells.