Screening Homing Peptide Of Bladder Cancer Cells EJ By Phage Display Peptide Library

Objective:To screen the peptides binding specifically to bladder cancer cells EJ form Ph.D-7^TM Phage Display Peptide Library in vitro.Methods:Using bladder cancer cells EJ as target cells and human normal bladder epithelial cells as adsorption cells,the Ph.D-7^TM Phage Display Peptide Library was selected for 3 rounds of subtractive screening in vitro.Then 30 positive phage clones picked randomly were identified their affinity with EJ cells by ELISA.The DNA of phage clones specifically binding to EJ cells were extracted,sequenced and analyzed.This bladder tumor homing peptide and its control peptide were compounded by solid phase chemical synthesis method.The effects of the polypeptide on the growth of EJ cells were studied by MTT test and cell injury repair test.Results:1.After three rounds of"screening,amplification and re-screening",the phages specifically binding to EJ cells were highly enriched,and the rate of recovery increased by nearly 200 times.2.Cell-ELISA analysis suggested that there were 17 positive phage clones with specific binding coefficient?2.3.The sequence of eight phage clones?R2,R5,R9,R12,R16,R17,R21,R24?was AVEAAKT.Its repeat rate was the highest and there was no homology.4.EJ cell-homing peptide AVEAAKT and its control peptide were prepared,and the purity was up to 95%.5.The results of MTT assay showed that the relative inhibition rate of the homing peptide and its control peptide was lower than 30%.The result of cell injury repair test showed that the cells of each group presented the same growth trend in unit time.It was confirmed that the homing peptide of bladder cancer had little effect on the growth of EJ cells.Conclusions:In this study,the peptide AVEAAKT,which can specifically bind to human bladder cancer cells EJ,was obtained by phage display technique in vitro.And it was confirmed that the peptide had little effect on the growth of EJ cells and there was no homology.Therefore,it may provide new ideas for early diagnosis and targeting therapy of bladder cancer.