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Ex Vivo Infection of Live Tissue with Oncolytic Viruses
Published on: June 25, 2011
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Experimental virus evolution in cancer cell monolayers, spheroids, and tissue explants
Ahmed Al-Zaher1, Pilar Domingo-Calap1, Rafael Sanjuán1
1Institute for Integrative Systems Biology (I2SysBio), Universitat de València-CSIC, C/ Catedrático Agustín Escardino 9, València 46980, Spain.
Virus Evolution
|May 27, 2021
Summary
Viral laboratory evolution in complex 3D cultures like spheroids and explants enhances virus fitness but reduces cancer cell selectivity compared to simple monolayers. Monolayer evolution offers more reproducible results and preserves oncolytic properties.
Area of Science:
- Virology
- Evolutionary Biology
- Cancer Research
Background:
- Viral laboratory evolution is crucial for applications like drug resistance prediction and optimizing therapeutic viruses.
- Studies predominantly use simplified cell monolayers, raising questions about their real-world applicability.
- Complex 3D culture models (spheroids, tissue explants) offer more physiologically relevant environments for viral evolution.
Purpose of the Study:
- To compare the laboratory evolution of an oncolytic virus (VSV-Δ51) in cell monolayers, spheroids, and tissue explants.
- To assess how different culture systems influence viral fitness, oncoselectivity, and genetic diversity.
- To determine the relevance of monolayer evolution for cancer virotherapy applications.
Main Methods:
- Serial transfer and adaptation of vesicular stomatitis virus (VSV-Δ51) in 4T1 mouse mammary tumor cells cultured as monolayers, spheroids, and tissue explants.
- Fitness assays to quantify viral adaptation.
- Deep sequencing to analyze viral genetic diversity.
- Assessment of oncoselectivity by testing viral adaptation to non-tumoral cells.
Main Results:
- VSV-Δ51 gained fitness across all three culture systems, with adaptation in complex systems correlating with increased monolayer fitness.
- Evolved viruses generally suppressed beta-interferon secretion, indicating conserved innate immune pressure.
- Monolayer-evolved viruses maintained higher oncoselectivity than spheroid-evolved viruses, which adapted to non-tumoral cells.
- Viral populations in monolayers and explants showed greater genetic diversity than those in spheroids.
- Explant evolution yielded highly variable outcomes across independent lines.
Conclusions:
- Experimental evolution in monolayers is more reproducible and better preserves oncoselectivity compared to spheroids or explants.
- While complex systems offer unique insights, monolayers capture relevant selective pressures for cancer virotherapy.
- The choice of culture system significantly impacts viral evolution outcomes and therapeutic potential.
