In the Genome Stability Laboratory we are using DT40 and human cells to study the DNA damage response (DDR). Our work impacts upon our understanding of cancer as abrogation of the DDR is causally implicated in oncogenesis. Furthermore, with the notable exception of surgery, many current cancer therapeutic approaches either introduce DNA damage or target the altered DDR of cancer cells. Improved understanding of how cells respond to DNA damage will result in improved cancer diagnosis, prognosis and therapeutic interventions.
The DDR is a complex, interacting network of biochemical pathways that ultimately prevents the accumulation of cells with mutations. This response constantly surveys the genome for damage that threatens its stability. Once structural alterations have been sensed there are five broad biological outcomes: 1) DNA repair; 2) transient delays to cell cycle progression (termed checkpoints); 3) a transcriptional programme; 4) programmed cell death (apoptosis) and 5) senescence. Failure to properly integrate these biological responses results in genome instability, which in turn can result in activation of proto-oncogenes or inactivation of tumour suppressors.
We use genetic approaches, including the latest CRISPR/Cas9 technologies, to manipulate target genes inorder to faciliate biochemical (Figure 2), genetic (Figure 3) or cell biological approaches (Figure 4). Biochemical approaches include quantitative proteomics (SILAC-assisted mass spectrometry) to identify new players in the DDR (for example, see Pessina and Lowndes 2013). Genetic approaches include targeting endogenous genes using CRISPR/Cas9 technologies to introduce sequences encoding the Auxin Inducible Degron so that genes can be conditionally ‘knocked-out’ (see Eykelenboom et al 2014 for a recent example using classical gene targeting in DT40 cells).