Common fragile sites (CFSs) are large chromosomal regions that exhibit gaps and breaks on metaphase chromosomes upon replication stress. They are unstable at early stages of cancer development and are often associated with chromosomal rearrangements in cancer. Since CFSs are part of the normal chromosomes, it is important to understand how CFSs are protected to maintain genome stability, thereby preventing cancer development. In this study, we propose to investigate the underlying mechanisms of how DNA damage checkpoint and DNA double-strand break (DSB) repair networks function to preserve genome integrity at CFSs. First, we will study the role of the replication machinery and replication checkpoints in the protection of stalled replication forks at CFSs. We will also investigate the involvement of replication fork regression in removing DNA secondary structures at CFSs and protecting for fork stability. Second, we will use our newly established EGFP-based repair substrates to study the pathways that are utilized to repair DSBs associated with CFSs. Since pathway choice would influence repair fidelity and genome stability at CFSs, understanding the DSB repair mechanisms to protect CFSs is extremely important for revealing the cause of cancer-related DNA lesions at CFSs. Third, oncogene expression induces CFS instability, but it remains unknown how such instability leads to cancer-prone DNA lesions. We will study the types of DNA lesions formed upon oncogene expression, and probe the roles of DNA repair and the checkpoint network in the prevention of oncogene-induced genome instability at CFSs. These studies will significantly help understand the mechanisms of cancer development that is associated with CFSs, and provide insight into cancer etiology. They will also help develop novel therapeutic strategies to prevent CFS-associated tumorigenesis.

Public Health Relevance

Common fragile sites (CFSs) are specific chromosomal regions that are prone to forming chromosomal gaps and breaks, and are often associated with chromosomal rearrangements in cancer. Since CFSs are part of normal chromosomal structures present in all human individuals, the maintenance of CFS stability is extremely important for the prevention of cancer. In this grant application, we propose to study the mechanisms of how CFSs are protected to prevent genome instability, which will provide insight into how cancer is developed and help design therapeutic strategies to prevent CFS-associated tumorigenesis.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA187052-01A1
Application #
8964289
Study Section
Radiation Therapeutics and Biology Study Section (RTB)
Program Officer
Pelroy, Richard
Project Start
2015-08-01
Project End
2020-07-31
Budget Start
2015-08-01
Budget End
2016-07-31
Support Year
1
Fiscal Year
2015
Total Cost
$433,481
Indirect Cost
$204,731
Name
Scripps Research Institute
Department
Type
DUNS #
781613492
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Wang, Hailong; Li, Shibo; Oaks, Joshua et al. (2018) The concerted roles of FANCM and Rad52 in the protection of common fragile sites. Nat Commun 9:2791
Wu, Yuehan; Lee, Suk-Hee; Williamson, Elizabeth A et al. (2015) EEPD1 Rescues Stressed Replication Forks and Maintains Genome Stability by Promoting End Resection and Homologous Recombination Repair. PLoS Genet 11:e1005675
Teixeira, Leonardo K; Wang, Xianlong; Li, Yongjiang et al. (2015) Cyclin E deregulation promotes loss of specific genomic regions. Curr Biol 25:1327-33