Modified Ad5 Oncolytic Virus with Capsid Mutations
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Solution Overview
Problem
The clinical efficacy of oncolytic adenovirus serotype Ad5 is hampered by poor tumour-specificity, extensive off-target delivery, and inactivation by innate immunity, necessitating innovative manipulation strategies to enhance its therapeutic effectiveness in cancer treatment.
Innovation Solution
A modified Ad5 serotype adenovirus is designed with specific point mutations in the hexon hypervariable region 7, fiber knob region AB loop, and penton integrin binding motif to prevent binding with coagulation factor 10, coxsackie and adenovirus receptor, and αvβ3/αvβ5 integrin, respectively, thereby reducing off-target infection and enhancing tumour specificity. Additionally, the virus is engineered to incorporate a cancer-targeting modification, such as the A20 peptide sequence, to selectively target αvβ6 integrin-expressing cancer cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ad5 is used as an oncolytic virus, then it can cause immunogenic cell death and prime immune responses, but it is rapidly inactivated by pre-existing neutralising antibodies in the host
Solution Approach 1:
The patent modifies the viral capsid proteins (hexon, fiber, penton) through specific point mutations to alter the virus's binding parameters. These mutations change the viral tropism and reduce recognition by pre-existing neutralising antibodies, allowing the virus to evade immune inactivation while maintaining oncolytic activity.
2Productivity
If Ad5 is systemically delivered, then it can reach tumor cells, but it is extensively sequestered to off-target organs via bridging interactions
Solution Approach 1:
The patent extracts and eliminates the harmful bridging interactions between the viral hexon protein and heparan sulphate proteoglycans (HSPGs) on off-target organs. By introducing point mutations in the hexon protein, the virus loses its ability to bind to HSPGs, thereby preventing sequestration in spleen and liver while maintaining tumor targeting capability.
Solution Approach 2:
The patent changes the binding parameters of the viral hexon protein through point mutations, altering its interaction profile with cellular receptors. This modifies the virus's tissue tropism to reduce off-target sequestration while preserving tumor cell entry capability.
3Ease of operation
If Ad5 uses its natural tropism via CAR binding, then it can enter host cells, but it lacks tumor specificity and infects cells with down-regulated CAR expression
Solution Approach 1:
The patent introduces local quality changes by adding tumor-specific targeting moieties (such as αvβ6 integrin-binding peptides) to the viral fiber protein. This creates heterogeneity in the viral surface properties, allowing the virus to selectively bind to tumor cells expressing specific markers while avoiding normal tissues.
Solution Approach 2:
The patent uses tumor-specific receptors (such as αvβ6 integrin) as intermediary binding sites to mediate viral entry into tumor cells. This intermediary mechanism provides a new entry pathway that is specifically expressed on tumor cells, enabling selective infection without relying on the non-specific CAR receptor.
4Manufacturing precision
If multiple point mutations are introduced to improve tumor specificity, then off-target infection is reduced, but the viral structure becomes more complex
Solution Approach 1:
The patent segments the viral capsid into distinct functional regions (hexon, fiber, penton proteins) and introduces targeted mutations in specific segments. This modular approach allows independent optimization of each protein's function to achieve tumor specificity without requiring complete redesign of the entire viral structure.
Data Source
AI summary
The invention concerns a modified oncolytic adenovirus of serotype Ad5; a pharmaceutical composition comprising same; and a method of treating cancer using same wherein said modified adenovirus comprises at least one point mutation(s) in the hexon hypervariable region 7 (HVR7 mutation) to prevent virus binding with coagulation factor 10 (FX); at least one point mutation(s) in the fiber knob region AB loop (KO1 mutation) to prevent virus binding with the coxsackie and adenovirus receptor (CAR); and at least one point mutation(s) in the penton integrin binding motif Arg-Gly-Asp (RGD) to prevent virus binding with αvβ3/αvβ5 integrin.