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Approaches Towards the Inhibition of Anti-Apoptotic Proteins 10.17863/CAM.39376 iegre, jessica 000000029074653X Spring, David R 0000000173552824 Anti-apoptotic proteins play a fundamental role in cell survival. Under physiological conditions, such proteins trigger apoptosis in defective or damaged cells only; under pathological conditions, however, they can be dysregulated allowing the cells to survive despite being harmful. Considering the importance of anti-apoptotic proteins in many physio-pathological roles, their specific inhibition is an attractive strategy to develop safe therapeutics. This thesis describes the inhibition of two classes of anti-apoptotic proteins: 1) Inhibition of the anti-apoptotic protein CK2 to develop novel anti-cancer molecules targeting pockets outside the well-conserved ATP-binding site: -Using a Fragment-Based-Drug-Discovery (FBDD) approach twelve small molecule inhibitors of CK2 were developed. The lead molecule, 3l, inhibited the catalytic activity of CK2α by binding in the cryptic αD pocket with a Kd of 4 μM. 3l stopped proliferation of colorectal cancer cells with a GI50 of 10 μM and presented improved drug-like properties and selectivity compared to previously reported inhibitors. Remarkably, 3l has the potential to be developed into a potent and selective anticancer drug. -Using a combination of rational-based approach and peptide stapling, twenty-two conformationally-constrained peptides were generated to target the protein-protein interaction (PPI) of CK2 and affect its function. The lead peptide, P7-F1C5, presented a novel, highly-functionalised constraint that allowed the molecule to become cell-permeable, exert its anti-proliferative activity in cancerous cells, and to become resistant to serum proteases. P7-F1C5 is the first macromolecule reported in the literature that binds to CK2α with sub-micromolar affinity (Kd 150 nM), and that can act as a chemical probe for targeting the PPI of CK2. 2) Inhibition of the anti-apoptotic Bcl-2 proteins to dissect their role in platelet activation and apoptosis. Bcl-2 proteins regulate cell lifespan; however, their role in non-nucleated platelets is not fully understood. The elucidation of these pathways in platelets is crucial to the development of selective anti-platelet therapeutics. To this end, this thesis describes the development and the first application of twenty-seven BH3-only peptides in human platelets highlighting how peptides can provide an alternative to conventional methodologies to study PPIs in platelets. The most promising peptide, P9-F5C5, engaged the anti-apoptotic protein Bcl-xL with 26 nM affinity and reviled a new role for the protein Bim in platelet activation. University of Cambridge 2019-07-19 Thesis Doctoral Doctor of Philosophy (PhD) en Trinity College https://www.repository.cam.ac.uk/handle/1810/292226 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/52bac316-da5b-4136-8175-cd0419ab6ec6/download 1dc710f26553c341dbdc9654823a05a6 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/8c449e72-d7b3-4ad9-ae5e-24b0afd90622/download 87eda9de84448d1f82354d60eee3eb5f https://www.rioxx.net/licenses/all-rights-reserved/ stapled peptides FBDD Peptides