Chicken-Derived Humanized Antibody Targeting a Novel Epitope F2pep of Fibroblast Growth Factor Receptor 2: Potential Cancer Therapeutic Agent

Fibroblast growth factors (FGFs) and their receptors control various biological functions. Dysregulated FGF signaling has been implicated in the pathogenesis of human cancers. Aberrant activation of FGF receptor 2 (FGFR2) signaling caused by FGFR2 overexpression has been observed in various human cancers, such as gastric cancer. Antibodies are highly suitable for target therapy because of their specificity toward FGFR2. Patients with cancer and aberrantly activated FGFR2 signaling can benefit from therapeutic intervention with FGFR2-targeting antibodies. In this study, we produced the anti-FGFR2 single-chain variable fragment (scFv) from immunized chickens through the phage display method. The isolated scFv S3 targeted designed epitope F2pep of FGFR2 and prevented the access of FGFs; thus, it exhibited the ability to inhibit cell growth in gastric cancer. Furthermore, scFv S3 recognized endogenous FGFR2 on the cancer cells and inhibited downstream cell signaling. To study the inhibition effect of the huma...