REPROGRAMMING PROLIFERATION: MOLECULAR STRATEGIES AGAINST GLIOBLASTOMA & BACTERIAL PERSISTENCE

Glioblastoma and bacterial persistence, though biologically distinct, pose a shared clinical challenge due to their resilience against pharmaceutical intervention. Part One of this work aims to address limitations in the treatment of glioblastoma, which currently consists of tumour removal and placement of a solid chemotherapy into the resection cavity. This treatment is undoubtedly flawed due to insufficient surface coverage and the high rate of relapse that follows. Our work aims to develop a new post-operative brain implant containing a Mannose Binding Lectin (MBL) inhibitor. Studies have shown that inhibition of MBL, an activator of the Complement System, can reduce the loss of sensorimotor capabilities after traumatic brain injury or stroke. The exact relation between MBL and glioblastoma tumour progression remains unclear, with different research providing conflicting outcomes. This section reports the optimised half gram synthesis of a multivalent MBL inhibitor for formulation into a hydrogel-based glioblastoma chemotherapy. For the development of more potent inhibitors, the synthesis of a novel multivalent scaffold was developed to better mimic the MBLs native glycans. This therapy has the potential to protect the brain from overstimulation of the Complement System during surgical recovery and to probe the role of MBL in glioblastoma relapse Part Two investigates the molecular switch of the obscure phenotypic antibiotic resistance, i.e. temporary antibiotic tolerance. These elusive sub-populations called Persisters, can be multidrug tolerant, and often contribute to chronic and recurring infections. Furthermore, bacterial persistence is considered a starting point for genetically antibiotic-resistant bacteria. The main theory behind the switch to a persistent phenotype is the cellular accumulation of the bacterial signalling molecule, guanosine penta- or tetra-phosphate, (p)ppGpp. Concentrations of (p)ppGpp are controlled by the superfamily of RSH (RelA/ SpoT Homologue) proteins, making them potential targets for drug development. A library of anthranilic acid centred compounds were designed via in-silico structure-based design (SBD) to inhibit the synthetase active site of our model RHS protein RelSeq (S. equisimilis). This section discusses the optimised synthesis of key derivatives within the library of deceptively simple compounds. To enable 19F NMR analysis of protein–ligand interactions, we engineered the large multidomain RelSeq using 5-F-Trp labelling. 19F NMR chemical shift perturbation assays were demonstrated as a potential tool to understand the ligands binding site. These insights will support validation of SBD computational methods and optimisation of more potent inhibitors, advancing the goal of reducing chronic infections and limiting antibiotic resistance.