In cancer, progression from a normal to a fully tumourigenic phenotype involves the accumulation of mutations in genes, which control cell function. Since the acquisition of each tumour cell phenotype (immortalisation, transformation and metastasis) is associated with distinct sets of mutations, targeting mutated gene products that confer each of these tumour-specific phenotypes should be a good anti-cancer strategy. The successful treatment of cancer will require the availability of suitable therapeutic substances against a significant number of targets. We will study targets that we have identified as being very suitable. We will also attempt to identify new targets in areas where suitable therapies are lacking.
This proposal brings together groups with a very high level of expertise in structural biology, screening and design to find suitable lead molecules, as well as in identification and validation of both targets and leads using mammalian genetics and mouse gene "knock-outs". The studies of the different targets that we propose will, if successful, lay the foundation for exploitation in a full scale effort in medicinal chemistry and pharmaceutical drug discovery.
Description of the work
In this proposal we will extend our previous studies of key targets in the Rb/p53 biochemical pathways that are controlled by the cyclin D-dependent kinases and the p19ARF/Mdm2/p53 interaction. We will investigate a number of new pathways that are controlled by Ras- and Rho-family small G proteins, with an emphasis on targets that might be important in preventing metastasis and invasion. In parallel, we will attempt to identify new targets using retroviral screening technologies and we will also further study the Ras -> Ral cascade and RhoA-induced apoptosis and transformation.
A major aim will be to learn how to most effectively inhibit protein-protein interactions. We will combine site-directed mutagenesis with studies of the energetics, with a view to understanding, and possibly ultimately being able to predict, which regions are best targeted. We will combine computational and experimental approaches, using NMR spectroscopy, to design suitable molecules that might interact tightly and specifically with flatter protein surfaces. In parallel, we will develop new methodology to extend the NMR method to larger proteins and complexes by encapsulating them in reverse micelles formed in low viscosity solvents. Finally, we will develop new in vivo assays to find inhibitors of protein-protein interactions.
Milestones and expected results
We will attempt to identify small molecules, typically peptides that have a desired inhibitory function, e.g. of a kinase or of a particular protein-protein interaction. Together with the structures that we determine, such peptides will be used to further validate targets and will provide initial information for the rational design of non-peptide leads for exploitation in full scale drug discovery. Our studies of protein-protein interactions, when taken together, should considerably enhance our knowledge of whether and how it will be possible to attack these traditionally more difficult targets.
Funding SchemeCSC - Cost-sharing contracts
WC2A 3NL London
TW8 9GS Brentford
WC1N 1EH London