DNA double-strand breaks (DSBs) are common lesions that continually threaten genomic integrity. Failure to repair a DSB has deleterious consequences, including cell death. Misrepair is also fraught with danger, especially inappropriate end-joining events, which commonly underlie oncogenic transformation and can scramble the genome. Canonically, cells employ two basic mechanisms to repair DSBs: homologous recombination (HR) and the classical nonhomologous end-joining pathway (cNHEJ). More recent experiments identified a highly error-prone NHEJ pathway, termed alternative NHEJ (aNHEJ), which operates in both cNHEJ-proficient and cNHEJ-deficient cells. aNHEJ is now recognized to catalyze many genome rearrangements, some leading to oncogenic transformation. Here, we review the mechanisms of cNHEJ and aNHEJ, their interconnections with the DNA damage response (DDR), and the mechanisms used to determine which of the three DSB repair pathways is used to heal a particular DSB. We briefly review recent clinical applications involving NHEJ and NHEJ inhibitors.
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http://dx.doi.org/10.1146/annurev-genet-110711-155540 | DOI Listing |
Nucleic Acids Res
January 2025
Kansai Institute for Photon Science, National Institutes for Quantum Science and Technology (QST), 8-1-7 Umemidai, Kizugawa-shi, Kyoto 619-0215, Japan.
Ionizing radiation induces various types of DNA damage, and the reparability and lethal effects of DNA damage differ depending on its spatial density. Elucidating the structure of radiation-induced clustered DNA damage and its repair processes will enhance our understanding of the lethal impact of ionizing radiation and advance progress toward precise therapeutics. Previously, we developed a method to directly visualize DNA damage using atomic force microscopy (AFM) and classified clustered DNA damage into simple base damage clusters (BDCs), complex BDCs and complex double-strand breaks (DSBs).
View Article and Find Full Text PDFCytokine Growth Factor Rev
January 2025
Center for Precision Medicine, China Medical University Hospital, China Medical University, Taichung, Taiwan; Department of Pathology, College of Medicine, China Medical University, Taichung, Taiwan. Electronic address:
Receptor tyrosine kinases (RTKs) are membrane sensors that monitor alterations in the extracellular milieu and translate this information into appropriate cellular responses. Epidermal growth factor receptor (EGFR) is the most well-known model in which gene expression is upregulated by mitogenic signals through the activation of multiple signaling cascades or by nuclear translocation of the full-length EGFR protein. RON (Receptuer d'Origine Nantatise, also known as macrophage stimulating 1 receptor, MST1R) has recently gained attention as a therapeutic target for human cancer.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Immunology and Molecular Oncology Diagnostics, Veneto Institute of Oncology IOV-IRCCS, 35128 Padua, Italy.
Increased expression of branched-chain amino acid (BCAA) transaminase 1 (BCAT1) often correlates with tumor aggressiveness and drug resistance in cancer. We have recently reported that BCAT1 was overexpressed in a subgroup of T-cell acute lymphoblastic (T-ALL) samples, especially those with NOTCH1 activating mutations. Interestingly, BCAT1-depleted cells showed pronounced sensitivity to DNA-damaging agents such as etoposide; however, how BCAT1 regulates this sensitivity remains uncertain.
View Article and Find Full Text PDFBiomedicines
December 2024
Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 8 Akad. Lavrentyeva pr., Novosibirsk 630090, Russia.
The nervous system is susceptible to DNA damage and DNA repair defects, and if DNA damage is not repaired, neuronal cells can die, causing neurodegenerative diseases in humans. The overall picture of what is known about DNA repair mechanisms in the nervous system is still unclear. The current challenge is to use the accumulated knowledge of basic science on DNA repair to improve the treatment of neurodegenerative disorders.
View Article and Find Full Text PDFSci Rep
January 2025
Reproductive Biology Laboratory, Centre for Reproductive Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, 1105AZ, The Netherlands.
Radiation therapy is a common treatment modality for lung cancer, and resistance to radiation can significantly affect treatment outcomes. We recently described that lung cancer cells that express more germ cell cancer genes (GC genes, genes that are usually restricted to the germ line) can repair DNA double-strand breaks more rapidly, show higher rates of proliferation and are more resistant to ionizing radiation than cells that express fewer GC genes. The gene encoding TRIP13 appeared to play a large role in this malignant phenotype.
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