Title: Characterising novel regulators of the PI-3-kinase-like kinase-dependent DNA damage response and their role in preventing human disease and cancer
Funder: Cancer Research UK

Abstract: Background: The cellular DNA damage response (DDR) is a complex network of pathways coordinated by the PI-3-kinase-like kinases (PIKKs), ATM, ATR and DNA-PK. Mutations in DDR components underlie a number of human genome instability and cancer predisposition disorders, highlighting the importance of the DDR in safeguarding genomic integrity and preventing cellular transformation. Importantly, our increased understanding of the PIKK-dependent DDR has led to the generation of inhibitors specifically targeting individual components of this pathway, which are being successfully used in the clinic to selectively kill DNA repair-deficient tumours in a synthetically lethal manner. Aims: Multiple regulatory proteins function to finely tune the PIKK-dependent DDR in response to specific genotoxic lesions. This programme aims to functionally characterise several such novel regulators and elucidate their roles in maintaining genome stability and preventing cancer development: Methods: WP1: Dissecting the role of tumour suppressor protein Nibrin in the cellular response to replication stress using a unique ‘separation-of-function’ mutant. We will use a unique NBN mutation that is proficient for DNA repair, but defective for dealing with replication damage, to understand which functions of Nbn are required to maintain genome stability and suppress tumourigenesis, using both in vitro and in vivo assays. WP2: Characterisation of a novel factor that regulates ATM/ATR-dependent signalling. We have recently identified a novel factor that is crucial for maintaining replication fork stability. We aim to define how this protein coordinates PIKK activation using in vitro kinase assays, and examine the impact of its over-expression on tumourigenesis using xenograft mouse models. WP3: Understand how BOD1L promotes DNA double strand break (DSB) repair by regulating end-resection. Our preliminary observations indicate that BOD1L plays a role in DSB repair. We aim to investigate the underlying mechanism using well-characterised resection assays, whilst also examining the impact of BOD1L loss on tumour development in vivo. WP4: Characterisation of a novel regulator of DSB repair. We have recently identified an uncharacterised protein that functions to regulate the DNA-PK-dependent DDR. We aim to delineate how this new factor regulates repair, and how its catalytic activities contribute to this, using both cellular and biochemical assays. How the results will be used: The data from these objectives will increase our knowledge about how defects in the PIKK-dependent DDR contribute to cellular transformation and impact on therapeutic efficacy. Furthermore, this research will also identify potential targets for therapeutic intervention aimed at inducing catastrophic levels of genome instability in tumour cells. (Cancer sites: Leukaemia, Non-Hodgkin's Lymphoma)


Research activity codes: 2.1 BIOLOGICAL AND ENDOGENOUS FACTORS;1.1 NORMAL BIOLOGICAL DEVELOPMENT AND FUNCTIONING
Health categories: CANCER AND NEOPLASMS;GENERIC HEALTH RELEVANCE