Inhibition of FGFR2 signaling is promising in targeted therapy of
FGFR2-related tumors. In this study, anti-FGFR2 nanobodies (Nbs) were
isolated through screening of an immune camelid phage display library.
Four rounds of biopanning were carried out with commercial human FGFR2
antigen and enrichment was assessed by ELISA and phage titration. The
gene of Nb was sub-cloned into the expression vector, and the
recombinant vector was transformed into Escherichia coli WK6
cells. The recombinant protein was purified using Ni-NTA affinity
chromatography. The anti-FGFR2 Nb (C13) was characterized by SDS-PAGE,
western blotting, competitive inhibition ELISA, flow cytometry, MTT, and
migration assay. C13 Nb recognized FGFR2 with high specificity and no
cross-reactivity was observed with other tested antigens. The affinity
of C13 Nb was calculated to be 1.5 × 10-9 M. Results of cytotoxicity showed that C13 Nb (10 µg/ml) inhibited 85% of the proliferation of T-47D cells (p < 0.001). In addition, C13 inhibited the migration of 68% of T-47D toward the source of the growth factor (p < 0.01). The flow cytometry showed that C13 Nb bound to the surface of FGFR2+
cells, T-47D cell line (96%). Results indicate the potential of
anti-FGFR2 Nb for targeted therapy of FGFR2-overexpressing tumors after
complementary investigations.