Proteolysis targeting chimeras for the directed ubiquitination of the androgen receptor

Proteolysis targeting chimeras (PROTACs) are an emerging field of therapeutics and promising potential drug candidates. PROTACs consist of a target protein binder connected via a linker to an E3 ligase binder. PROTACs hijack the ubiquitin proteasome system to degrade the target protein in a cellular environment. This work focuses on the androgen receptor (AR) protein, a key nuclear receptor for healthy prostate development. Hence, AR inhibition and degradation are well-established strategies for treatment of prostate cancer. First, in this work stapled peptide PROTACs recruiting E3 ligase MDM2 for AR degradation were investigated. MDM2 has been underexploited as an E3 ligase for PROTACs, despite a beneficial ability to modulate the p53 protein, a vital tumour suppressor, in additional to inducing protein degradation. Using a two-component peptide stapling strategy, stapled peptide PROTACs were developed for AR degradation via recruitment of MDM2. Stapled peptides are commonly used to target challenging protein-protein interactions, such as MDM2-p53. Peptides are capable of emulating elements of protein structure, offering significant advantages over small molecule alternatives. Second, a series of small molecule MDM2 recruiting PROTACs were synthesised to establish a novel ligand capable of expanding the PROTAC toolbox. Finally, photoswitchable AR degrading PROTACs were synthesised. The photophysics and biological activity of the PROTACs were analysed. These PROTACs integrated ortho-fluoroazobenzene for light-induced conformational change. Incorporating photoswitchable moieties in pharmaceutical entities has been demonstrated to mitigate off-target toxicity, a promising strategy to reduce attrition rates in drug discovery. Improved selectivity, efficacy, and overall safety profiles could be delivered by dosing an inactive drug and using light to modulate its biological activity at the site of action.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2020

Author dc:creator

• Fowler, Elaine

Advisor dc:contributor.advisor

• Spring, David

• PROTAC
• MDM2
• Androgen Receptor
• Photoswitch
• Azobenzene

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/1612c13c-d456-4bc7-bc77-1ad879d03166/download
• https://www.rioxx.net/licenses/all-rights-reserved/

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.52529

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/305449