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Saxena S, Nabel CS, Seay TW, Patel PS, Kawale AS, Crosby CR, Tigro H, Oh E, Vander Heiden MG, Hata AN, Suo Z, Zou L. Unprocessed genomic uracil as a source of DNA replication stress in cancer cells. Mol Cell 2024:S1097-2765(24)00282-X. [PMID: 38688279 DOI: 10.1016/j.molcel.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 03/26/2024] [Accepted: 04/05/2024] [Indexed: 05/02/2024]
Abstract
Alterations of bases in DNA constitute a major source of genomic instability. It is believed that base alterations trigger base excision repair (BER), generating DNA repair intermediates interfering with DNA replication. Here, we show that genomic uracil, a common type of base alteration, induces DNA replication stress (RS) without being processed by BER. In the absence of uracil DNA glycosylase (UNG), genomic uracil accumulates to high levels, DNA replication forks slow down, and PrimPol-mediated repriming is enhanced, generating single-stranded gaps in nascent DNA. ATR inhibition in UNG-deficient cells blocks the repair of uracil-induced gaps, increasing replication fork collapse and cell death. Notably, a subset of cancer cells upregulates UNG2 to suppress genomic uracil and limit RS, and these cancer cells are hypersensitive to co-treatment with ATR inhibitors and drugs increasing genomic uracil. These results reveal unprocessed genomic uracil as an unexpected source of RS and a targetable vulnerability of cancer cells.
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Affiliation(s)
- Sneha Saxena
- Mass General Cancer Center, Harvard Medical School, Charlestown, MA, USA
| | - Christopher S Nabel
- Mass General Cancer Center, Harvard Medical School, Charlestown, MA, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Turner W Seay
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Parasvi S Patel
- Mass General Cancer Center, Harvard Medical School, Charlestown, MA, USA
| | - Ajinkya S Kawale
- Mass General Cancer Center, Harvard Medical School, Charlestown, MA, USA
| | - Caroline R Crosby
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Helene Tigro
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Eugene Oh
- Mass General Cancer Center, Harvard Medical School, Charlestown, MA, USA
| | - Matthew G Vander Heiden
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA, USA
| | - Aaron N Hata
- Mass General Cancer Center, Harvard Medical School, Charlestown, MA, USA; Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Zucai Suo
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Lee Zou
- Mass General Cancer Center, Harvard Medical School, Charlestown, MA, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA.
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