Production and radioimmunoimaging of novel fully human phage display recombinant antibodies and growth inhibition of lung adenocarcinoma cell line overexpressing Prx I

Abstract

The Peroxiredoxin I (Prx I) is a member of the Peroxiredoxin family, which is

overexpressed in many diverse tumor types and is an anti-apoptosis protein for tumor

cell proliferation and survival. Therapeutic strategies targeting the Prx I may therefore

be effective broad-spectrum anticancer agents. We construct a phage display

single-chain variable fragment (scFv) antibody library and sieve out the fully human,

lung adenocarcinoma-sepcific monoclonal antibodies. The selection on Prx I was

performed using above-mentioned lung adenocarcinoma-sepcific monoclonal

antibodies with high affinity to Prx I overexpressing lung adenocarcinoma cells. The

candidate scFv sequences, based on enzyme-linked immunosorbent assay (ELISA)

screening data, were chosen for soluble expression, and a 30 kDa band was observed

on polyacrylamide gel electrophoresis as predicted. The purified antibodies were

characterized by immunoblotting and showed high specificity to Prx I-overexpressing

lung adenocarcinoma cells A549. Radioimmunoimaging was taken to evaluate

specificity and distribution of antibodies in vivo. The radiolocalization index (RI) of

tumor/serum and tumor/muscle gradually increased, reaching its peak (4.06±0.13 and

5.17±0.97, respectively) at 48 h postadministration. Single photon emission computed

tomography (SPECT) imaging showed the radioactivity was aggregated in tumor

locations and tumor imaging was clearly observed. The internalized scFv resulted in

antibody-mediated cell apoptosis and down regulation of Prx I expression. These

results demonstrate that the scFv possesses strong antitumor activity on lung

adenocarcinoma and may therefore be an effective therapeutic candidate for the

treatment of cancers that are dependent on Prx I for growth and survival.