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Updated: Jun 27, 2026
A GPC3-targeting Bispecific Antibody, GPC3-S-Fab, with Potent Cytotoxicity
Published on: July 12, 2018
Targeting CD16A on NK cells and GPC3 in hepatocellular carcinoma: development and functional validation of a
Liu Chen1, Yuankui Zhu1, Mingqian Feng1,2
1College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
Introduction:
Advanced hepatocellular carcinoma (HCC) poses significant therapeutic challenges due to chemotherapy resistance and limited efficacy of current targeted therapies. To address this unmet need, we developed a bispecific antibody (BsAb) platform targeting CD16A on natural killer (NK) cells and glypican-3 (GPC3), a tumor-specific antigen overexpressed in 70% of HCC cases.
Methods:
High-affinity anti-CD16A single-chain variable fragments (scFvs) were selected via phage display, followed by engineering of Fc-stabilized BsAbs (MA4-hFc(N297A)-CD16A series) to minimize FcγR-mediated toxicity. Functional validation included binding kinetics (ELISA, flow cytometry, and fluorescence co-localization analysis), in vitro cytotoxicity assays (luciferase-based killing), and in vivo efficacy studies in Huh7 xenograft models. Synergy with sorafenib was assessed using CompuSyn analysis.
Results:
The lead candidate, MA4-hFc-CD16AM19, exhibited nanomolar affinity (EC50 < 10 nM for human CD16A) with no murine cross-reactivity. It demonstrated potent, dose-dependent cytotoxicity against GPC3+ HCC lines (HepG2/Huh7/Hep3B, IC50 = 15-35 ng/mL) via NK cell activation, surpassing conventional antibody-dependent cellular cytotoxicity (ADCC). Combined with sorafenib, MA4-hFc-CD16AM19 achieved synergistic tumor suppression (CI=0.41). In vivo, BsAb treatment (5 mg/kg) significantly inhibited tumor growth in xenograft models, correlating with enhanced intratumoral NK cell infiltration without toxicity.
Conclusion:
This study introduces three innovations: (1) a species-specific CD16A binder overcoming polymorphism limitations, (2) Fc domain engineering (N297A) to optimize stability and safety, and (3) a synergistic combination strategy with sorafenib. The results provide a translatable framework for GPC3+ solid tumor immunotherapy.
Insights
A novel bispecific antibody (BsAb) targets CD16A and GPC3 for advanced hepatocellular carcinoma (HCC) immunotherapy. This BsAb shows potent NK cell-mediated cytotoxicity and synergistic effects with sorafenib, offering a promising new treatment strategy.
Area of Science:
- Immunology
- Oncology
- Biotechnology
Background:
- Advanced hepatocellular carcinoma (HCC) presents therapeutic challenges due to chemoresistance.
- Current targeted therapies for HCC have limited efficacy.
- Glypican-3 (GPC3) is a tumor-specific antigen overexpressed in most HCC cases.
Purpose of the Study:
- To develop a bispecific antibody (BsAb) platform targeting CD16A on natural killer (NK) cells and GPC3 in HCC.
- To engineer Fc-stabilized BsAbs to minimize FcγR-mediated toxicity.
- To evaluate the efficacy of the BsAb, alone and in combination with sorafenib, for HCC treatment.
Main Methods:
- Selection of high-affinity anti-CD16A single-chain variable fragments (scFvs) via phage display.
- Engineering of Fc-stabilized BsAbs with minimized FcγR-mediated toxicity.
- Functional validation using binding kinetics, in vitro cytotoxicity assays, and in vivo xenograft models.
Main Results:
- The lead BsAb candidate, MA4-hFc-CD16AM19, demonstrated nanomolar affinity for human CD16A.
- Potent, dose-dependent cytotoxicity against GPC3+ HCC lines was observed via NK cell activation.
- Synergistic tumor suppression was achieved when combined with sorafenib (CI=0.41).
- In vivo studies showed significant inhibition of tumor growth without toxicity.
Conclusions:
- The developed BsAb platform offers a translatable framework for GPC3+ solid tumor immunotherapy.
- Fc domain engineering (N297A) optimized BsAb stability and safety.
- A synergistic combination strategy with sorafenib enhances therapeutic potential.
