Interference with DNA Repair Mechanisms of Mammalian Cells: Cell Cycle Dependence

Author(s):  
Arthur B. Pardee ◽  
Robert J. Boorstein ◽  
Ching C. Lau
2021 ◽  
Vol 22 (24) ◽  
pp. 13296
Author(s):  
Mariarosaria De Falco ◽  
Mariarita De Felice

All organisms have evolved many DNA repair pathways to counteract the different types of DNA damages. The detection of DNA damage leads to distinct cellular responses that bring about cell cycle arrest and the induction of DNA repair mechanisms. In particular, DNA double-strand breaks (DSBs) are extremely toxic for cell survival, that is why cells use specific mechanisms of DNA repair in order to maintain genome stability. The choice among the repair pathways is mainly linked to the cell cycle phases. Indeed, if it occurs in an inappropriate cellular context, it may cause genome rearrangements, giving rise to many types of human diseases, from developmental disorders to cancer. Here, we analyze the most recent remarks about the main pathways of DSB repair with the focus on homologous recombination. A thorough knowledge in DNA repair mechanisms is pivotal for identifying the most accurate treatments in human diseases.


Author(s):  
Benjamin Foster ◽  
Martin Attwood ◽  
Ian Gibbs-Seymour

The maintenance of genome stability requires dedicated DNA repair processes and pathways that are essential for the faithful duplication and propagation of chromosomes. These DNA repair mechanisms counteract the potentially deleterious impact of the frequent genotoxic challenges faced by cells from both exogenous and endogenous agents. Intrinsic to these mechanisms, cells have an arsenal of protein factors that can be utilised to promote repair processes in response to DNA lesions. Orchestration of the protein factors within the various cellular DNA repair pathways is performed, in part, by post-translational modifications, such as phosphorylation, ubiquitin, SUMO and other ubiquitin-like modifiers (UBLs). In this review, we firstly explore recent advances in the tools for identifying factors involved in both DNA repair and ubiquitin signaling pathways. We then expand on this by evaluating the growing repertoire of proteomic, biochemical and structural techniques available to further understand the mechanistic basis by which these complex modifications regulate DNA repair. Together, we provide a snapshot of the range of methods now available to investigate and decode how ubiquitin signaling can promote DNA repair and maintain genome stability in mammalian cells.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Birgit Lohberger ◽  
Dietmar Glänzer ◽  
Nicole Eck ◽  
Sylvia Kerschbaum-Gruber ◽  
Elisabeth Mara ◽  
...  

AbstractAlthough particle therapy with protons has proven to be beneficial in the treatment of chondrosarcoma compared to photon-based (X-ray) radiation therapy, the cellular and molecular mechanisms have not yet been sufficiently investigated. Cell viability and colony forming ability were analyzed after X-ray and proton irradiation (IR). Cell cycle was analyzed using flow cytometry and corresponding regulator genes and key players of the DNA repair mechanisms were measured using next generation sequencing, protein expression and immunofluorescence staining. Changes in metabolic phenotypes were determined with nuclear magnetic resonance spectroscopy. Both X-ray and proton IR resulted in reduced cell survival and a G2/M phase arrest of the cell cycle. Especially 1 h after IR, a significant dose-dependent increase of phosphorylated γH2AX foci was observed. This was accompanied with a reprogramming in cellular metabolism. Interestingly, within 24 h the majority of clearly visible DNA damages were repaired and the metabolic phenotype restored. Involved DNA repair mechanisms are, besides the homology directed repair (HDR) and the non-homologous end-joining (NHEJ), especially the mismatch mediated repair (MMR) pathway with the key players EXO1, MSH3, and PCNA. Chondrosarcoma cells regenerates the majority of DNA damages within 24 h. These molecular mechanisms represent an important basis for an improved therapy.


2017 ◽  
Author(s):  
Charlotte R. Pfeifer ◽  
Yuntao Xia ◽  
Kuangzheng Zhu ◽  
Dazhen Liu ◽  
Jerome Irianto ◽  
...  

AbstractCancer cell invasion into tissue or narrow capillaries often elongates the nucleus and sometimes damages it, but cell cycle effects are unknown and highly relevant to tumorigenesis. Here, nuclear rupture and DNA breaks caused by constricted migration are quantified in different phases of cell cycle - which is effectively repressed. Cancer lines with varying levels of contact inhibition and lamina proteins exhibit diverse frequencies of nuclear lamina rupture after migration, with prerupture dilation of gene-edited RFP-Lamin-B1 preceding DNA repair factor leakage in pressure-controlled distension. Post-migration rupture indeed associates with mis-localized DNA repair factors and increased DNA breaks as quantified by pan-nucleoplasmic foci of γH2AX, with foci counts always suppressed in late cell cycle. When contact-inhibited cells migrate through large pores into sparse microenvironments, cells re-enter cell cycle consistent with release from contact inhibition. In contrast, constricting pores effectively delay re-entry, but the excess DNA damage nonetheless exceeds any cell cycle dependence. Partial depletion of topoisomerase does not strongly affect cell cycle or the excess DNA damage, consistent with weak dependencies on replication stress. Constricted migration thus impacts cell cycle as well as DNA damage.


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