Abstract A13: Identification of evolutionarily conserved genetic interactions in DNA mismatch repair

The DNA mismatch repair (MMR) system is responsible for correcting base substitution and insertion-deletion mutations (IDLs) generated during erroneous replication in bacteria, yeast and mammals. MMR complexes also recognize damaged-base mispairs resulting from environmental exposure to DNA damaging agents. The loss of MMR causes a “mutator” phenotype, resulting in the genome-wide accumulation of mutations, and is the underlying cause for Hereditary Non-polyposis Colorectal Cancer / Lynch Syndrome (HNPCC/LS) and a significant proportion of sporadic colorectal cancer (CRC). MMR-deficient tumors also display resistance to DNA damaging agents and, as a consequence, are resistant to a variety of commonly chemotherapeutic agents. Thus, the development of novel therapeutic strategies that more efficiently target MMR-deficient cancer cells would be highly desirable. A promising new direction to identify potential targets for anticancer treatment is the harnessing of synthetic lethality. Here, we have identified conserved synthetic lethal / sick genetic interactions (GIs) for MMR factors between two distant yeast species, S. pombe and S. cerevisiae . We have confirmed several of these negative GIs in mammalian cells, indicating that they are evolutionarily conserved. Specifically, we have identified a negative genetic relationship between Msh2, a major MMR component mutated in colorectal cancer, and Senp6 protease, which regulates the SUMOylation of a range of genome maintenance proteins. Our findings suggest that Senp6 is a promising new target for the treatment of MMR-deficient CRCs. Citation Format: Elena Tosti, Joseph A. Katakowski, Sonja Schaetzlein, Hyun-Soo Kim, Colm J. Ryan, Michael Shales, Assen Roguev, Nevan J. Krogan, Deborah Palliser, Michael-Christopher Keogh, Winfried Edelmann. Identification of evolutionarily conserved genetic interactions in DNA mismatch repair. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Synthetic Lethal Approaches to Cancer Vulnerabilities; May 17-20, 2013; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(5 Suppl):Abstract nr A13.