A novel specific small molecule peptide for non-small cell lung cancer cell A549

To screen small molecule peptide specific binding to non-small cell lung cancer cell (A549) using the "one-bead one-peptide" combinatorial library. Twenty-nine positive beads binding to A549 cell were totally obtained after primary screening. Consensus peptide sequence of -NGXG- was identified by amino acid sequencing in ten beads. Peptide cNGQGEQc was re-synthesized on beads and further studied for its cell specificity, alanine scanning and site-directed deletion. The results showed that cNGQGEQc is specific for cell attachment to non-small cell lung cancer cells including A549, Calu-I and H178, but not to other tumor cell lines. Both motif of -NGXG- and the length of six peptides are very important for A549 adhesion. Peptide cNGQGEQc labeled with FITC can specifically bind to A549 cell. In a blocking assay with anti-integrin antibodies(α 1-6, αv/β1-5), cell adhesion of A549 to peptide beads was obviously inhibited by integrin α3 combining with any αsubunits. Results suggested that small molecule peptide cNGQGEQc can bind specifically to non-small cell lung cancer cell A549 via integrin α3 on cell surface.