Aim: To identify linear peptide homing to non-small cell lung cancer (NSCLC) tumor cells using ex vivo phage display method.
Materials and methods: Twenty-six clinical patient samples were used to identify linear homing peptide, which was exposed to NSCLC cell cultures and control cell lines to determine cell binding affinity and cell localization. Also, ex vivo biodistribution was analyzed using tumor-bearing mice.
Results: The panning yielded peptide enrichment with a core motif (A)/SRXPXXX. Based on this, an amino acid sequence, ARRPKLD, was selected for characterization and named Thx-peptide. The in vitro binding properties of Thx-peptide demonstrated selectivity toward NSCLC. Internalization assays showed that Thx-Alexa and fluorescein conjugates were located in a subset of perinuclearly located lysosomes of tumor cells. Thx-peptide appeared with fluorescein-labeled peptide and peptide-DTPA-chelator complex in adenocarcinoma xenografts in mice.
Conclusion: Thx shows promise for targeted imaging and drug delivery.