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Updated: Jun 25, 2026
Placing Growth Factor-Coated Beads on Early Stage Chicken Embryos
Published on: October 1, 2007
Impact of humanization scaffold design on the functional activity of FGFR2-targeting chicken scFvs
Shyi-Chun Yii1, Tsai-Yu Lin2, Fu-Ling Chang2
1Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan; Divisions of Urology, Department of Surgery, Far Eastern Memorial Hospital, New Taipei, Taiwan.
Abstract:
Fibroblast growth factor receptor 2 (FGFR2) is frequently overexpressed in gastric cancer and represents a promising therapeutic target. We developed FGFR2-specific single-chain variable fragments (scFvs) using a chicken-derived immune library and a refined cell-based panning strategy incorporating FGFR2-knockdown cells for negative selection. The lead clone, scFv R21, exhibited high binding affinity and strong tumor-inhibitory effects in vitro. To enable therapeutic application, R21 was humanized using three distinct framework strategies: CDR grafting, light chain replacement, and structure-guided back-mutation. Structural modeling by AlphaFold3 indicated that the hR21-Bf variant preserved CDR conformation and overall stability. Despite lower expression, hR21-Bf retained moderate FGFR2 binding affinity (KD) of 38 nM, while other variants showed markedly reduced reactivity. The hR21-Bf construct was further reformatted as a full-length human IgG1 and evaluated in a gastric cancer xenograft model. Mice treated with IgG hR21-Bf showed significant tumor growth inhibition without observable toxicity. Immunohistochemical and biochemical analyses of resected tumors confirmed reduced Ki-67 expression and downregulation of FGFR2-mediated signaling. Our study highlights the impact of scaffold selection on antibody structure and function, supporting a rational approach to antibody humanization using avian-derived libraries for cancer therapy.
Insights
Researchers developed a humanized antibody targeting Fibroblast Growth Factor Receptor 2 (FGFR2) for gastric cancer therapy. The antibody demonstrated significant tumor growth inhibition in preclinical models with no observed toxicity, highlighting its therapeutic potential.
Area of Science:
- Oncology
- Immunology
- Biotechnology
Background:
- Fibroblast Growth Factor Receptor 2 (FGFR2) overexpression is common in gastric cancer, making it a potential therapeutic target.
- Developing effective FGFR2-specific therapies is crucial for improving gastric cancer treatment outcomes.
Purpose of the Study:
- To develop and humanize an FGFR2-specific single-chain variable fragment (scFv) for potential gastric cancer therapy.
- To evaluate the therapeutic efficacy and safety of the humanized antibody in preclinical gastric cancer models.
Main Methods:
- Generated FGFR2-specific scFvs using a chicken immune library and cell-based panning with negative selection.
- Humanized the lead scFv clone (R21) using CDR grafting, light chain replacement, and structure-guided back-mutation.
- Reformatted the humanized antibody as IgG1 and tested in a gastric cancer xenograft mouse model.
Main Results:
- The humanized antibody variant hR21-Bf showed moderate FGFR2 binding affinity (38 nM) and preserved structural integrity.
- Treatment with IgG hR21-Bf significantly inhibited gastric tumor growth in mice.
- Tumor analyses confirmed reduced proliferation (Ki-67) and suppressed FGFR2 signaling.
Conclusions:
- Humanization of avian-derived scFvs is feasible and can yield effective therapeutic antibodies.
- The humanized FGFR2 antibody (IgG hR21-Bf) shows promise as a targeted therapy for gastric cancer.
- This study supports rational antibody humanization strategies for cancer treatment development.
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