Our trillions of cells receive thousands of DNA lesions daily, whether through physiological processes or insults and toxins. To monitor and protect their genomes, eukaryotic cells have evolved sophisticated DNA-damage response (DDR) systems that comprise DNA repair and DNA-damage signaling processes. But sometimes these repair machineries go awry. Accumulation of damaged DNA can have major consequences, from cell death to cancer. One of the most common forms of breast cancer is caused by mutations in BRCA1/2, which are an important part of a particular type of DNA repair called homologous recombination.

Because DNA repair is so important, overloading a broken repair system can be an effective way to specifically kill cancer cells. So called "synthetic lethality" drugs trigger cell death only in cells that already have a DNA repair mutation. For example, Olaparib inhibits a DNA repair enzyme called PARP1, which has little effect in healthy cells but leads to death of BRCA1/2-mutant breast cancer cells. But the fundamental interactions between the DDR pathways that underly such therapeutic opportunities are still not well understood.

Unraveling the recipe for success in DNA damage control

The DDREAMM team aims to develop a comprehensive understanding of human DDR synthetic lethal and resistant interactions to characteristic types of DNA damage, specific mutations in DDR genes and DDR enzyme inhibitors in various human cell types. An interdisciplinary set of genetic, physical, and mechanistic experiments are combined to provide new fundamental mechanistic insights into DDR pathways, identify small molecule inhibitors of these targets and potentially nurture the development of new cancer treatments.

Genetic and functional interactions between DDR components

We use next-generation CRISPR inhibition and activation (CRISPRi/a) screening tools in genome-wide approaches to uncover hypo- and hyper-morph alleles that affect cellular sensitivity to DNA double strand breaks, DDR-enzyme inhibitors and DNA-damaging agents. This will provide insights into new DDR components and regulators, define functional interactions between them, and show how their deregulation affects cellular responses to DNA-damaging agents and DDR-enzyme inhibitors

Physical and mechanistic understanding of DDR synthetic lethalities and resistances

Using proteomics and mutational outcomes, mass spectrometry and in-depth mechanistic studies, we will establish physical interaction networks within the genetic framework and reveal the signaling logic that underpins DDR outcomes. New functional interactions between DDR components will lead to a broader systems-wide understanding of DDR events, how they impact on, and are affected by, other physiological parameters.

Chemical-genetics for small molecule modulators of DDR processes

We will follow up our genetic and mechanistic work by carrying out chemical-genetic screens. This will lead to the identification of compounds that result in resistance or sensitivity when combined with DNA damage or mutations in DDR genes. We will also search for inhibitors of proteins that elicit resistance or sensitivity to DNA damage or mutations in DNA repair genes. With these approaches, we will develop small molecule tools to precisely interrogate DDR pathways which could lead to the discovery of new therapeutic agents.