PARP inhibitors (PARPi) kill BRCA1/2-mutated cancers, which become resistant when DNA repair functions are restored. Now, MUS81 nuclease inhibition due to EZH2 downregulation is found to restore DNA replication fork protection but not repair, leading to PARPi-resistance in mutant BRCA2 cells and patients. This challenges the DNA repair dominance in synthetic lethality.
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http://dx.doi.org/10.1038/ncb3638 | DOI Listing |
Abasic sites are one of the most frequent forms of DNA damage that interfere with DNA replication. However, abasic sites exhibit complex effects because they can be processed into other types of DNA damage. Thus, it remains poorly understood how abasic sites affect replisome progression, which replication-coupled repair pathways they elicit, and whether this is affected by the template strand that is damaged.
View Article and Find Full Text PDFThe DNA damage response (DDR) mechanisms that allow cells to tolerate DNA replication stress are critically important for genome stability and cell viability. Using an unbiased genetic screen we identify a role for the RING finger E3 ubiquitin ligase RNF25 in promoting DNA replication stress tolerance. In response to DNA replication stress, RNF25-deficient cells generate aberrantly high levels of single-stranded DNA (ssDNA), accumulate in S-phase and show reduced mitotic entry.
View Article and Find Full Text PDFMol Cell
January 2025
Institute for Cancer Genetics and Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pediatrics and Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA. Electronic address:
DNA replication, a fundamental process in all living organisms, proceeds with continuous synthesis of the leading strand by DNA polymerase ε (Pol ε) and discontinuous synthesis of the lagging strand by polymerase δ (Pol δ). This inherent asymmetry at each replication fork necessitates the development of methods to distinguish between these two nascent strands in vivo. Over the past decade, strand-specific sequencing strategies, such as enrichment and sequencing of protein-associated nascent DNA (eSPAN) and Okazaki fragment sequencing (OK-seq), have become essential tools for studying chromatin replication in eukaryotic cells.
View Article and Find Full Text PDFCell Death Dis
January 2025
Tianjian Laboratory of Advanced Biomedical Sciences, Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China.
Mitochondrial oxidative phosphorylation (OXPHOS) is a therapeutic vulnerability in glycolysis-deficient cancers. Here we show that inhibiting OXPHOS similarly suppresses the proliferation and tumorigenicity of glycolytically competent colorectal cancer (CRC) cells in vitro and in patient-derived CRC xenografts. While the increased glycolytic activity rapidly replenished the ATP pool, it did not restore the reduced production of aspartate upon OXPHOS inhibition.
View Article and Find Full Text PDFNat Commun
January 2025
DNA Replication Group, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, UK.
Human DNA licensing initiates replication fork assembly and DNA replication. This reaction promotes the loading of the hMCM2-7 complex on DNA, which represents the core of the replicative helicase that unwinds DNA during S-phase. Here, we report the reconstitution of human DNA licensing using purified proteins.
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