University of Cambridge
Novel Proteolysis Targeting Chimeras for the targeted degradation of the protein kinase CK2
Abstract
dc:description.abstractHuman protein kinase CK2 is a constitutively active serine/threonine kinase involved in numerous biological processes and is frequently overexpressed in a multitude of different cancer types. Traditional ATP-competitive CK2 inhibitors, such as CX-4945, have demonstrated therapeutic potential, but they are often limited by off-target effects and a lack of prolonged suppression of CK2 activity. PROTACs (Proteolysis Targeting Chimeras) represent a novel therapeutic strategy that can induce target degradation through the 26S proteasome, offering potential advantages in potency, selectivity, and prolonged biological activity. The aim of this project was to develop novel CK2-targeting PROTACs by conjugating a CAM4066-derived warhead to Cereblon (CRBN) and Von Hippel–Lindau (VHL) E3-ligase ligands via a linker. The project was split into three stages: development of a synthetic route towards PROTACs; synthesis of PROTAC candidates, and evaluation of their biological activity in vitro. Four VHL-based PROTACs were successfully synthesised using PEG-based linkers and an alkyl linker, along with two CRBN-based PROTACs comprising constrained linkers. The VHL PROTACs are the first reported examples of VHL-based PROTACs designed to target CK2. Preliminary biological evaluation of a half-PROTAC (modified CK2 warhead comprising a linker) confirmed that linker incorporation was well tolerated. The half-PROTAC maintained binding affinity to CK2 at the same order of magnitude as CAM4066. The key binding interactions in the αD and ATP sites were also preserved. Despite the successful synthesis and promising preliminary data, the PROTACs did not induce significant CK2 degradation when tested on HCT-116 or MDA-MB-231 cells via Western blot analysis. Similarly, degradation of CK2 using a literature-reported PROTAC was not reproducible. Overall, this work established a synthetic route to CAM4066-based PROTACs and provided promising initial biological data for the development of CK2-targeting PROTACs. Ongoing efforts will focus on linker optimisation, alternative E3-ligase ligands, and further biological evaluation to enable the development of selective CK2-targeting PROTACs for therapeutic and research applications.
Degree
thesis:*- Name dc:type.qualificationname
- Doctor of Philosophy (PhD)
- Level dc:type.qualificationlevel
- Doctoral
- Grantor dc:publisher.institution
- University of Cambridge
- Year dc:date.issued
- 2025
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Day-Riley, Sophie
- Advisor dc:contributor.advisor
-
- Spring, David
Subjects
dc:subject × 5Rights
dc:rightsIdentifiers
dc:identifier.*- Author Identifier
- 0000-0001-7355-2824
- OAI identifier oai:identifier
- oai:www.repository.cam.ac.uk:1810/398925