Related Experiment Video
Updated: May 28, 2026
Combined Genetic and Chemical Capsid Modifications of Adenovirus-Based Gene Transfer Vectors for Shielding and Targeting
Published on: October 26, 2018
A cathepsin-cleavage site between the adenovirus capsid protein IX and a tumor-targeting ligand improves targeted
J de Vrij1, I J C Dautzenberg, S K van den Hengel
1Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
Abstract:
Human adenoviruses have a great potential as anticancer agents. One strategy to improve their tumor-cell specificity and anti-tumor efficacy is to include tumor-specific targeting ligands in the viral capsid. This can be achieved by fusion of polypeptide-targeting ligands with the minor capsid protein IX. Previous research suggested that protein IX-mediated targeting is limited by inefficient release of protein IX-fused ligands from their cognate receptors in the endosome. This thwarts endosomal escape of the virus particles. Here we describe that the targeted transduction of tumor cells is augmented by a cathepsin-cleavage site between the protein IX anchor and the HER2/neu-binding ZH Affibody molecule as ligand. The cathepsin-cleavage site did not interfere with virus production and incorporation of the Affibody molecules in the virus capsid. Virus particles harboring the cleavable protein IX-ligand fusion in their capsid transduced the HER2/neu-positive SKOV-3 ovarian carcinoma cells with increased efficiency in monolayer cultures, three-dimensional spheroid cultures and in SKOV-3 tumors grown on the chorioallantoic membrane of embryonated chicken eggs. These data show that inclusion of a cathepsin-cleavage sequence between protein IX and a high-affinity targeting ligand enhances targeted transduction. This modification further augments the applicability of protein IX as an anchor for coupling tumor-targeting ligands.
Insights
Adding a cathepsin-cleavage site to protein IX-fused ligands on adenoviruses improves tumor cell targeting. This enhances viral delivery for potential cancer therapies by facilitating endosomal escape.
Area of Science:
- Oncolytic virotherapy
- Molecular and Cellular Biology
- Biotechnology
Background:
- Human adenoviruses show promise as anticancer agents.
- Targeting ligands fused to capsid protein IX enhance tumor-cell specificity.
- Previous methods faced limitations due to inefficient ligand release from endosomal receptors.
Purpose of the Study:
- To improve targeted transduction of tumor cells using engineered adenoviruses.
- To investigate the efficacy of incorporating a cathepsin-cleavage site in protein IX-ligand fusions.
- To enhance endosomal escape and viral delivery to tumor cells.
Main Methods:
- Fusion of a HER2/neu-binding Affibody molecule to adenovirus protein IX via a cathepsin-cleavage site.
- Production and characterization of engineered adenovirus particles.
- Assessment of transduction efficiency in HER2/neu-positive SKOV-3 ovarian carcinoma cells using various culture models and in vivo chicken embryo models.
Main Results:
- The cathepsin-cleavage site did not impede virus production or Affibody incorporation into the capsid.
- Adenovirus particles with the cleavable protein IX-ligand fusion showed augmented transduction efficiency in SKOV-3 cells.
- Enhanced transduction was observed in monolayer cultures, 3D spheroid cultures, and in vivo tumor models.
Conclusions:
- Incorporating a cathepsin-cleavage sequence between protein IX and a targeting ligand significantly enhances targeted viral transduction.
- This strategy improves the applicability of protein IX as a versatile anchor for tumor-targeting ligands in adenoviral vectors.
- The engineered adenoviruses demonstrate increased potential for targeted cancer therapy.
More Related Videos
13:36Utilizing the Antigen Capsid-Incorporation Strategy for the Development of Adenovirus Serotype 5-Vectored Vaccine Approaches
Published on: May 6, 2015
11:58Initial Evaluation of Antibody-conjugates Modified with Viral-derived Peptides for Increasing Cellular Accumulation and Improving Tumor Targeting
Published on: March 8, 2018