Identification of a Novel Tumor-Binding Peptide for Lung Cancer Through in-vitro Panning

Tumor-targeted therapies are playing growing roles in cancer research. The exploitation of these powerful therapeutic modalities largely depends on the discovery of tumor-targeting ligands. Phage display has proven a promising high throughput screening tool for the identification of novel specific peptides with high binding affinity to cancer cells. In the present study, we describe the use of phage display to isolate peptide ligands binding specifically to human lung cancer cells. Towards this goal, we screened a phage display library of 7-mer random peptides in-vitro on non-small cell lung carcinoma (A549) as the target cell. Following selection rounds, there was a highly considerable enrichment of lung cancer-binding phages and a significant increase - 170 fold - of the phage recovery efficiency. After three rounds of in-vitro panning, a group of peptides with different frequencies were obtained. The binding efficiency and selectivity of these peptides for target and control cells were studied. The results of cellular binding assay and cell ELISA (enzyme-linked immunosorbent assay) revealed that LCP1 (Lung Cancer Peptide1) with the displayed sequence AWRTHTP is the most effective peptide in binding to lung cancer cells compared with normal lung epithelial cells and different non-lung tumor cells. In conclusion, our findings suggest that LCP1 may represent a novel peptide that binds specifically to lung cancer cells and further studies can pave the way for its application as a potential targeting moiety in the targeted delivery of diagnostic and therapeutic agents into lung malignant cells.