Specific lung cancer peptides selected by a subtractive 3D cell-phage display technology

Background: Despite advances of the lung cancer diagnosis in the last decades, it continues to be the leading cause of death due to neoplasia in the world. Aim: To select and characterize specific peptides to lung cancer cells since new biomarkers can improve the rapid screening and early diagnosis of lung cancer, allowing a medical intervention in an effective way. Methods: The present study describes a subtractive selection through phage display technology from 3D cell lines. Briefly, BEAS-2B (human bronchial epithelial) and A549 (human lung adenocarcinoma) cell lines were 3D cultured by the magnetic levitation method. For the negative selection, a commercial library of random peptides Ph-D. c7c was incubated with 3D BEAS-2B cells to ensure specificity only to the tumor. The non-adhered phages were submitted to positive selection against 3D A549 cells. Adherent phage clones to 3D A549 cells were selected, purified, identified by DNA sequencing and submitted to enzyme immunoassay (ELISA) and flow cytometry to confirm binding to A549 cells. Results: Twenty-three different phage clones were identified and their reactivity were tested by Phage-ELISA against A549 cells. Five clones were significantly bound to the tumor cells (P < 0.05), and two of them were more reactive (P < 0.01). The specificity of these two clones was confirmed by flow cytometry demonstrated by high affinity to bind to tumor cells (57 and 33%) when compared to normal cells (14 and 11%). Conclusion: We have identified two potential bacteriophage-fused peptides with high affinity to lung cancer cells, which can be used in the diagnosis of the lung cancer and possibly as drug carriers. Financial Support: FAPEMIG, CNPq, CAPES.