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Updated: Jan 10, 2026
Isolation of Next-Generation Gene Therapy Vectors through Engineering, Barcoding, and Screening of Adeno-Associated Virus AAV Capsid Variants
Published on: October 18, 2022
Antibody-guided AAV vectors for antigen-specific delivery of suicide genes
Shojiro Inano1,2, Hiroyuki Morita3, Daishi Nakagawa4
1Department of Early Clinical Development, Graduate School of Medicine, Kyoto University, Yoshida-Konoecho, Sakyo-ku, Kyoto, Japan. shoin@kuhp.kyoto-u.ac.jp.
Abstract:
Antibody-drug conjugates (ADCs) are a promising class of targeted cancer therapeutics, but their efficacy is often limited by off-target toxicity caused by payload leakage after internalization into tumor cells. To overcome this, we developed an ADC alternative using an antibody-guided adeno-associated virus (AAV) vector system that delivers suicide genes specifically to cancer cells. By displaying Protein A on the AAV VP2 capsid, we enabled IgG binding and stable complex formation on the capsid, leading to efficient antibody-guided transduction under our assay conditions. This modular platform allows flexible retargeting specific tumor-associated antigens simply by changing the antibody, without genetic re-engineering of the capsid. Using an AAV2 heparan sulfate binding knockout (HBKO) background to minimize nonspecific infection, we achieved antigen-specific transduction for multiple targets including CD20, EGFR, PSMA, CEA, and CD5 (with varying levels of enhancement depending on the target). In vitro, the system successfully directed EGFP expression and, upon delivery of the pro-apoptotic gene BAX, induced selective apoptosis in target-positive cells. Unlike conventional ADCs, this strategy is designed to minimize the risk of extracellular payload leakage and to confine cytotoxicity primarily to transduced cells, thereby supporting more selective tumor targeting. Our approach may offer a versatile alternative for targeted cancer therapy, with the potential for further development into customizable and precision-guided gene-based treatments.
Insights
This study introduces a novel antibody-guided adeno-associated virus (AAV) vector system as a cancer therapy alternative. It precisely targets cancer cells with suicide genes, reducing off-target toxicity compared to antibody-drug conjugates (ADCs).
Area of Science:
- Oncology
- Gene Therapy
- Virology
Background:
- Antibody-drug conjugates (ADCs) show promise in cancer therapy but face limitations due to off-target toxicity from payload leakage.
- Developing targeted delivery systems that minimize systemic exposure and maximize cancer cell specificity is crucial.
Purpose of the Study:
- To develop an alternative to ADCs using an antibody-guided adeno-associated virus (AAV) vector system for targeted cancer gene therapy.
- To create a modular platform for retargeting cancer cells by modifying the antibody component without re-engineering the viral capsid.
Main Methods:
- Engineered AAV VP2 capsid to display Protein A for IgG binding, enabling antibody-guided complex formation.
- Utilized an AAV2 heparan sulfate binding knockout (HBKO) background to reduce non-specific viral infections.
- Tested antigen-specific transduction targeting CD20, EGFR, PSMA, CEA, and CD5 in vitro, delivering EGFP and the pro-apoptotic gene BAX.
Main Results:
- Achieved antigen-specific transduction for multiple cancer targets with varying efficiency.
- Demonstrated successful EGFP expression and induced selective apoptosis in target-positive cancer cells upon BAX gene delivery.
- The system showed reduced risk of extracellular payload leakage compared to conventional ADCs.
Conclusions:
- The antibody-guided AAV vector system offers a versatile and potentially safer alternative for targeted cancer therapy.
- This platform enables customizable, precision-guided gene-based treatments with enhanced tumor selectivity.
- Further development could lead to advanced gene-based therapeutic strategies with minimized toxicity.
