Genomic instability is a hallmark of cancer. The maintenance of genomic stability relies on the concerted action of a number of cellular processes, such as DNA replication, DNA repair, and cell-cycle transitions. The central coordinator of these cellular processes is the DNA damage-signaling pathway, which is often referred to as the checkpoint. In human cells, the checkpoint is orchestrated by two master kinases, ATM and ATR. While ATM is critical for the response to DNA double-stranded breaks (DSBs), ATR responds to a much broader spectrum of DNA damage and DNA replication problems. How ATR is activated by various forms of DNA damage and replication stress is a fundamental question for the research of genome maintenance. ATR forms a complex with ATRIP in human cells. We and others have shown that single-stranded DNA (ssDNA) coated by RPA is the key structure at sites of DNA damage and stressed replication forks that recruits and activates ATR-ATRIP. Nevertheless, how exactly ATR-ATRIP is activated on RPA-ssDNA and how it regulates DNA repair is still poorly understood. In this study, we have found that ATRIP is SUMOylated in a DNA damage-stimulated manner, and that ATRIP SUMOylation plays a key role in ATR activation. Furthermore, we have identified a novel function of ATR in homologous recombination (HR), providing a critical clue to the role for ATR in DNA repair. Mostly excitingly, we found that cancer cells with specific genetic alterations are addicted to the HR pathway and highly sensitive to ATR inhibitors, presenting a conceptually new way to target ATR in cancer therapy. In this application, we propose to address (1) how ATRIP SUMOylation drives ATR activation, (2) how ATR regulates HR, and (3) how to target ATR in cancers. If successful, our studies will greatly advance our understanding of the mechanism of ATR activation, the role for ATR in DNA repair, and the potential of ATR as a therapeutic target. Our research may ultimately bring the mechanistic studies on ATR to the rational use of ATR inhibitors in targeted cancer therapy.

Public Health Relevance

Genomic instability is a hallmark of cancer and an attractive target for therapy. We will investigate how ATR, a master DNA damage-signaling kinase in human cells, is activated by DNA damage and how it regulates DNA repair. Furthermore, we will explore how to attack specific vulnerabilities of cancer cells by inhibiting ATR.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM076388-10
Application #
8884966
Study Section
Molecular Genetics B Study Section (MGB)
Program Officer
Willis, Kristine Amalee
Project Start
2006-09-25
Project End
2019-08-31
Budget Start
2015-09-01
Budget End
2016-08-31
Support Year
10
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
073130411
City
Boston
State
MA
Country
United States
Zip Code
Nguyen, Hai Dang; Leong, Wan Yee; Li, Weiling et al. (2018) Spliceosome Mutations Induce R Loop-Associated Sensitivity to ATR Inhibition in Myelodysplastic Syndromes. Cancer Res 78:5363-5374
Teng, Yaqun; Yadav, Tribhuwan; Duan, Meihan et al. (2018) ROS-induced R loops trigger a transcription-coupled but BRCA1/2-independent homologous recombination pathway through CSB. Nat Commun 9:4115
Kabeche, Lilian; Nguyen, Hai Dang; Buisson, Rémi et al. (2018) A mitosis-specific and R loop-driven ATR pathway promotes faithful chromosome segregation. Science 359:108-114
Yazinski, Stephanie A; Comaills, Valentine; Buisson, Rémi et al. (2017) ATR inhibition disrupts rewired homologous recombination and fork protection pathways in PARP inhibitor-resistant BRCA-deficient cancer cells. Genes Dev 31:318-332
Ouyang, Jian; Lan, Li; Zou, Lee (2017) Regulation of DNA break repair by transcription and RNA. Sci China Life Sci 60:1081-1086
Guarner, Ana; Morris, Robert; Korenjak, Michael et al. (2017) E2F/DP Prevents Cell-Cycle Progression in Endocycling Fat Body Cells by Suppressing dATM Expression. Dev Cell 43:689-703.e5
Buisson, Rémi; Lawrence, Michael S; Benes, Cyril H et al. (2017) APOBEC3A and APOBEC3B Activities Render Cancer Cells Susceptible to ATR Inhibition. Cancer Res 77:4567-4578
Buisson, Rémi; Niraj, Joshi; Rodrigue, Amélie et al. (2017) Coupling of Homologous Recombination and the Checkpoint by ATR. Mol Cell 65:336-346
Nguyen, Hai Dang; Yadav, Tribhuwan; Giri, Sumanprava et al. (2017) Functions of Replication Protein A as a Sensor of R Loops and a Regulator of RNaseH1. Mol Cell 65:832-847.e4
Comaills, Valentine; Kabeche, Lilian; Morris, Robert et al. (2016) Genomic Instability Is Induced by Persistent Proliferation of Cells Undergoing Epithelial-to-Mesenchymal Transition. Cell Rep 17:2632-2647

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