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Unravelling Receptor and RGD Motif Dependence of Retargeted Adenoviral Vectors using Advanced Tumor Model Systems
M Chernyavska1, M Schmid2, P C Freitag2
1Department of Biochemistry, Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Geert Grooteplein 28, 6525 GA, Nijmegen, The Netherlands.
Abstract:
Recent advances in engineering adenoviruses are paving the way for new therapeutic gene delivery approaches in cancer. However, there is limited knowledge regarding the impact of adenoviral retargeting on transduction efficiency in more complex tumor architectures, and the role of the RGD loop at the penton base in retargeting is unclear. To address this gap, we used tumor models of increasing complexity to study the role of the receptor and the RGD motif. Employing tumor-fibroblast co-culture models, we demonstrate the importance of the RGD motif for efficient transduction in 2D through the epithelial cell adhesion molecule (EpCAM), but not the epidermal growth factor receptor (EGFR). Via optical clearing of co-culture spheroids, we show that the RGD motif is required for transduction via both receptors in 3D tumor architectures. We subsequently employed a custom-designed microfluidic model containing collagen-embedded tumor spheroids, mimicking the interplay between interstitial flow, extracellular matrix and adenoviral transduction. Image analysis of on-chip cleared spheroids indicated the importance of the RGD motif for on-chip adenoviral transduction. Together, our results show the interrelationship between receptor characteristics, the RGD motif, the 3D tumor architecture and retargeted adenoviral transduction efficiency. The findings are important for the rational design of next-generation therapeutic adenoviruses.
Insights
The RGD motif is crucial for efficient adenoviral gene delivery in complex 3D tumor models, regardless of the specific receptor used. This finding aids in designing better cancer therapies.
Area of Science:
- Biomedical Engineering
- Gene Therapy
- Oncology
Background:
- Adenoviral vectors are promising for cancer gene therapy.
- Understanding retargeting efficiency in complex tumor environments is crucial.
- The role of the RGD motif in adenoviral retargeting remains unclear.
Purpose of the Study:
- To investigate the impact of adenoviral retargeting on transduction efficiency in increasingly complex tumor models.
- To clarify the role of the RGD motif at the penton base in retargeting.
- To examine the interplay between tumor architecture, receptors, and adenoviral transduction.
Main Methods:
- Utilized tumor models of increasing complexity, including 2D co-cultures and 3D spheroids.
- Employed optical clearing techniques for enhanced visualization.
- Developed a custom microfluidic model simulating interstitial flow and extracellular matrix interactions.
- Analyzed adenoviral transduction efficiency via image analysis of cleared spheroids.
Main Results:
- The RGD motif is essential for efficient transduction in 2D models via EpCAM but not EGFR.
- In 3D tumor architectures, the RGD motif is required for transduction mediated by both EpCAM and EGFR.
- Microfluidic models confirmed the RGD motif's importance for on-chip adenoviral transduction.
- Demonstrated a clear interrelationship between receptor characteristics, RGD motif, 3D architecture, and transduction efficiency.
Conclusions:
- The RGD motif plays a critical role in adenoviral transduction efficiency within complex 3D tumor structures.
- Findings highlight the importance of considering tumor architecture and RGD motif for designing effective next-generation therapeutic adenoviruses.
- This research provides insights for the rational design of targeted adenoviral gene delivery systems in cancer therapy.
