Anti-ABCG2 scFv antibody of lung adenocarcinoma increases chemosensitivity and induces apoptosis through the activation of mitochondrial pathway.

ABCG2 is a multidrug resistance efflux pump expressed in many diverse tumors. The overexpression of ABCG2 is associated with resistance to a wide variety of anticancer agents, providing a noticeable setback to successful cancer therapy. Therapies targeting ABCG2 may therefore be a promising candidate for reversal of chemoresistance. The anti-ABCG2 single-chain variable fragment (scFv) antibody was constructed by phage display peptide library technology. Immunoblotting, ELISA and immunocytochemistry were used to evaluate the soluble expression and immunoreactivity of the scFv. The effects of scFv on cell function and chemosensitization were confirmed by colony formation, cell migration and CCK-8 assays. Flow cytometry was used to analyse the cell cycle and apoptosis. Radioimmunoimaging and nude mouse tumorigenicity assays were taken to determine the biodistribution and antitumor capacity of the scFv antibody. We have successfully screened out the candidate scFv antibody with an apparent molecular weight of 34 kDa. The scFv demonstrated favourable binding ability to lung adenocarcinoma cells and ABCG2 antigen, and the radioactivity was specifically aggregated at the tumor location. Furthermore, the internalized scFv resulted in antibody-mediated downregulation of ABCG2, proliferation inhibition, apoptosis and cisplatin (DDP) sensitivity. The anti-ABCG2 scFv antibody possesses good tumoraffin and antitumor activity and may therefore be an effective therapeutic agent for lung adenocarcinoma that is dependent on ABCG2 for drug resistance and survival.