p53, encoded by the TP53 gene, is a critical tumour-suppressor gene that is mutated in half of all human cancers. Many of these mutants occur in the DNA binding domain and diminish either the stability of the protein or its interaction with DNA. Several small molecules that are designed to rescue the activity of mutant p53 are currently undergoing clinical trials. However, none of these molecules are likely to be a panacea for restoring p53 mutant activities, and new therapeutic modalities are sorely needed. An exciting avenue is the use of metal complexes as the basis of radically new scaffolds and developing them into therapeutic leads with metal-specific mechanisms of action. The project aims to rationally construct metal-based complexes using a fragment-based drug discovery approach as this is a barely explored, yet highly promising alternative approach. Through iterative cycles of chemical synthesis, structural biology, biophysical techniques, in vitro binding assays and cell-based assays, we will rationally develop metal-based probes targeting p53 that are potential small molecule leads. These probes will reveal whether metal complexes can restore the cellular function of p53. This is a crucial question that could open the door to the future development of new anti-cancer agents.
Objective 1 – Year 1-2
Fluorescent-based thermal shift assays of the in-house fragment libraries of expressed and purified p53 to identify chemical starting points.
Objective 2 – Year 2-3
Validation of hits and identification of the binding sites of the metallo-fragments on p53. Initiation of iterative make-test cycles to elaborate hits and explore structure-activity-relationship (SAR) through structural guidance.
Objective 3 – Year 3-4
Evaluation of high affinity complexes with phenotypic and in vivo assays.
The rotation project would entail (i) the recombinant production and purification of mutant p53, (ii) the establishment of a high-throughput assay for p53 binding using known binders as positive controls, and (iii) the in silico and biophysical screening of geometrically diverse metal complexes for binding to mutant p53.
