Establishing new technologies for the development of targeted virotherapies

Cunliffe, Tabitha 2023. Establishing new technologies for the development of targeted virotherapies. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Despite improvements in cancer treatments, there is still an unmet clinical need for effective therapeutic agents that are highly tumour specific. Oncolytic viruses hold many characteristics required for such agents, through their multi-faceted cell killing mechanisms. In particular, adenovirusbased oncolytic viruses show promise as they are easy to manipulate and have a proven safety profile in the clinic. A limiting factor for the use of these agents is the lack of suitable methods for exploiting cancer-specific receptor ligand interactions. Here, we sought to evaluate both rational and irrational approaches for the identification and exploitation of cancer-specific ligands into an adenoviral vector. The irrational approach aimed to graft the Ad5 knob protein (Ad5K) onto tailed phage P2 for subsequent hypermutation and directed evolution of the Ad5K towards cancer-specific receptors. A proof-of-principle study showed that P2 could be retargeted towards a proteinaceous receptor, OmpC, through chimeric tail fibres with a secondary phage S16. This work has additional importance for biomedical applications for new antimicrobial agents. The production of important reagents, antiP2 and anti-knob antibodies, for the evaluation of P2 chimeric particles was attempted, with the production of anti-P2 being successful. However, analysis of P2 particles with Ad5K engrafted did not show conclusive evidence on successful display or retargeting to the receptors of interest. The rational approach interrogated the crystal structure of EGFR:EGF, where key binding residues were identified and incorporated into permissive loops in the Ad5K protein. None of the five Ad5K-EGF constructs showed significant retargeting towards EGFR. Additional optimisation of this rational approach is required in further study. Although the main aim of this research to display and hypermutate the Ad5K on phage particles was unsuccessful, this research provides knowledge of research areas that are not successful and thus can inform future directions of study.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Medicine
Funders:	KESS2
Date of First Compliant Deposit:	12 May 2023
Last Modified:	12 May 2023 09:40
URI:	https://orca.cardiff.ac.uk/id/eprint/159423

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