Identifying peptides that specifically bind to MDA-MB-468 breast cancer cells*

Abstract

Abstract Objective To use phage display technique to screen for small polypeptides that specifically bind to MDAMB-468 cells. Methods A random heptapeptide phage display library was used for in vitro screening against target MDA-MB-468 cells. SC1180 cells were used for subtractive selection. High-affinity phage DNA was extracted, and peptides were sequenced. Results (1) The original library capacity of the polypeptide library was 2 × 1013 pfu/mL, and phage titer was determined over 4 rounds. The average library capacity was 1.8 × 1013 pfu/mL. (2) Subtractive screening showed that the phage library volume of each round was 1.8 × 1012 pfu/mL, and that there was an enrichment effect in each subsequent round. Screening was stopped after the fourth round. (3) PCR results showed that the size of 39 products (78.0%) and 11 products (22%), were 300 bp and 258 bp, respectively. Thirty positive phages were selected for DNA extraction and sequencing, and the corresponding amino acid sequence was LMTRXSK. The sequence had no homology with known genes or proteins. Conclusion Using the phage display technique, we identified that the short polypeptide, LMTRXSK, specifically binds MDA-MB-468 human breast cancer cells.