Screening and identification of CD44v9 specific peptide ligand for gastric cancer detection / 西安交通大学学报(医学版)

ABSTRACT

【Objective】 To screen and verify a peptide ligand specific for CD44v9. 【Methods】 A 12-mer phage peptide library was screened on CD44v9 coated on solid phase. Candidate sequences emerged after sequencing. Candidate phages were selected using enzyme-linked immunosorbent assay. The best sequence was chosen for further study. Binding of C9-3 to CD44v overexpressed HEK-293 cells was determined using immunofluorescence. Binding affinity and specificity were verified on gastric cancer tissues with immunohistochemistry. 【Results】 Phages significantly were enriched during panning process. After sequencing, nine individual sequences occurred in 30 selected clones. Among the 9 candidate sequences, C9-3 exhibited the highest frequency. Results of ELISA showed that C9-3 had the highest OD value and selectivity. Thus, C9-3 was chosen for peptide probe synthesis. C9-3 probe stained CD44v overexpressed HEK-293 cells, but not empty vector transfected HEK-293 cells. Immunohistochemistry scores of C9-3 were significantly different between gastric cancer and paracancer tissues (t=3.953, P<0.01). A linear positive correlation was observed between C9-3 binding and CD44v9 expression (r=0.823, P<0.01). 【Conclusion】 In this study, peptide ligand of CD44v9 was successfully screened. The peptide can bind to cells and cancer tissues via CD44v9. It has potential for gastric targeting probes.