Cancer and Genome Instability Group

The genome of every cell is constantly exposed to endogenous and exogenous factors that directly damage DNA. Their misrepair can trigger genome rearrangements that cause a plethora of inherited human syndromes with life-threatening complications including cancer, immunodeficiency and premature ageing. To prevent catastrophic changes to the information encoded in our DNA a complex network of proteins has evolved to maintain genome integrity. A characteristic feature of cancer cells is a breakdown of the repair processes, which leads to the genome becoming unstable, a process that is essential for tumourigenesis.

Our research focuses on understanding the basic molecular mechanisms by which cells detect and repair damaged DNA, and how to exploit this knowledge to improve cancer therapies.

We are particularly interested in how the repair of damaged DNA is executed during the process of genome duplication, and how chromosomal stability is achieved under stressful conditions. To address these questions, we employ state-of-the art techniques including monitoring of DNA replication at the single molecule level in living cells, isolation of proteins on newly replicated DNA (to identify novel components of the replication machinery) and super-resolution microscopy for live-cell imaging.

A long-term goal of our research is to elucidate the mechanisms by which cells maintain integrity of their genetic information and translate these basic scientific findings into the development of novel therapies for cancer.

Understanding DNA repair pathways, and how deficiencies in these pathways cause human disease requires the elucidation of a series of very complex events, including:

• Identifying the constituents of multi-protein complexes

• Characterising protein–protein interactions

• Determining protein localisations and post-translational modifications

• Reconstituting functional activity from purified components in vitro.

To comprehend these complex events we are focusing on three principle areas of research:

1. Understanding the mechanism and regulation of DNA double strand break repair

Currently we are attempting to identify and characterise how the various proteins that make up the DNA resection machinery contribute to the repair of one of the most toxic lesions that cells can suffer i.e. DNA double strand breaks (DSBs). Our lab uses high-throughput technologies, including genomic-proteomic pipelines combined with mass spectrometry-based analysis, bioinformatics and real time live cell imaging. The identification of novel co-factors that cooperate with the resection machinery to promote DSB repair could aid the development of novel treatment strategies to combat cancer and other hereditary disorders.

2. Investigating the molecular mechanisms of cellular responses to replicative stress

The ability of cells to divide allows organisms to grow and reproduce. This process requires copying and maintaining a vast amount of genetic information. Therefore, accurate replication of DNA is essential not only for the preservation of genomic integrity but also the continuation of life. To accomplish this, cells have evolved complex mechanisms to both replicate cellular DNA with high fidelity and to preserve its integrity.

Nevertheless, genomic integrity is challenged during every cell cycle by lesions present in the DNA template that can collapse the replication machinery, contributing to tumour progression by driving chromosomal instability. Our goal is to understand cellular strategies that prevent replication perturbation and mechanisms by which cells accomplish genome duplication under conditions of replicative stress. Ultimately, we want to use this information for the implementation of novel cancer treatment options.

3. Understanding the DNA repair mechanisms disrupted in the childhood cancer predisposing syndrome Fanconi anemia

Children afflicted with Fanconi anemia (FA) show developmental defects, progressive bone marrow failure and have up to 1000-fold increased risk of cancer. The genes mutated in this syndrome encode a network of ‘caretaker’ proteins, which not only ensure that DNA is accurately copied but also prevent replication failure and associated genomic instability. Consequently, a properly functioning FA pathway is important for normal development, haematopoiesis and suppression of solid tumours in everyone. This underscores the essential role of this pathway in suppressing tumour formation.

We are particularly interested in understanding how the FA proteins function to promote genome stability, and whether dysfunctional replication-mediated DNA repair is a common signal that drives FA disease progression to leukaemia. A long-term goal of our research is to elucidate the FA-dependent mechanism required to suppress the devastating haematological and malignant conditions associated with FA and use this information for the development of novel treatment options for FA sufferers.