scholarly journals Mutational impact and signature of ionizing radiation

2021 ◽  
Author(s):  
Jeonghwan Youk ◽  
Hyun Woo Kwon ◽  
Joonoh Lim ◽  
Eunji Kim ◽  
Ryul Kim ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ionizing Radiation ◽  
Mammalian Cells ◽  
Single Cells ◽  
Dna Double Strand Breaks ◽  
Structural Variations ◽  
Dna Damage And Repair ◽  
Repair Processes ◽  
Massive Number ◽  
Chaotic Nature

AbstractWhole-genome sequencing (WGS) of human tumors and normal cells exposed to various carcinogens has revealed distinct mutational patterns that provide deep insights into the DNA damage and repair processes. Although ionizing radiation (IR) is conventionally known as a strong carcinogen, its genome-wide mutational impacts have not been comprehensively investigated at the single-nucleotide level. Here, we explored the mutational landscape of normal single-cells after exposure to the various levels of IR. On average, 1 Gy of IR exposure generated ∼16 mutational events with a spectrum consisting of predominantly small nucleotide deletions and a few characteristic structural variations. In ∼30% of the post-irradiated cells, complex genomic rearrangements, such as chromoplexy, chromothripsis, and breakage-fusion-bridge cycles, were resulted, indicating the stochastic and chaotic nature of DNA repair in the presence of the massive number of concurrent DNA double-strand breaks. These mutational signatures were confirmed in the genomes of 22 IR-induced secondary malignancies. With high-resolution genomic snapshots of irradiated cells, our findings provide deep insights into how IR-induced DNA damage and subsequent repair processes operate in mammalian cells.

scholarly journals βarrestin-1 regulates DNA repair by acting as an E3-ubiquitin ligase adaptor for 53BP1

2019 ◽  
Vol 27 (4) ◽  
pp. 1200-1213 ◽  
Author(s):  
Ainhoa Nieto ◽  
Makoto R. Hara ◽  
Victor Quereda ◽  
Wayne Grant ◽  
Vanessa Saunders ◽  
...  
Keyword(s):  
Dna Damage ◽  
Ionizing Radiation ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Strand Break ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Molecular Scaffold ◽  
Strand Breaks

Abstract Cellular DNA is constantly under threat from internal and external insults, consequently multiple pathways have evolved to maintain chromosomal fidelity. Our previous studies revealed that chronic stress, mediated by continuous stimulation of the β2-adrenergic-βarrestin-1 signaling axis suppresses activity of the tumor suppressor p53 and impairs genomic integrity. In this pathway, βarrestin-1 (βarr1) acts as a molecular scaffold to promote the binding and degradation of p53 by the E3-ubiquitin ligase, MDM2. We sought to determine whether βarr1 plays additional roles in the repair of DNA damage. Here we demonstrate that in mice βarr1 interacts with p53-binding protein 1 (53BP1) with major consequences for the repair of DNA double-strand breaks. 53BP1 is a principle component of the DNA damage response, and when recruited to the site of double-strand breaks in DNA, 53BP1 plays an important role coordinating repair of these toxic lesions. Here, we report that βarr1 directs 53BP1 degradation by acting as a scaffold for the E3-ubiquitin ligase Rad18. Consequently, knockdown of βarr1 stabilizes 53BP1 augmenting the number of 53BP1 DNA damage repair foci following exposure to ionizing radiation. Accordingly, βarr1 loss leads to a marked increase in irradiation resistance both in cells and in vivo. Thus, βarr1 is an important regulator of double strand break repair, and disruption of the βarr1/53BP1 interaction offers an attractive strategy to protect cells against high levels of exposure to ionizing radiation.

scholarly journals Characteristics of mutational signatures of unknown etiology

NAR Cancer ◽  
2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Xiaoju Hu ◽  
Zhuxuan Xu ◽  
Subhajyoti De
Keyword(s):  
Dna Damage ◽  
Point Mutations ◽  
Gc Content ◽  
Unknown Origin ◽  
Unknown Etiology ◽  
Mutational Signatures ◽  
Dna Damage And Repair ◽  
Disease Etiology ◽  
Repair Processes ◽  
A Genome

Abstract Although not all somatic mutations are cancer drivers, their mutational signatures, i.e. the patterns of genomic alterations at a genome-wide scale, provide insights into past exposure to mutagens, DNA damage and repair processes. Computational deconvolution of somatic mutation patterns and expert curation pan-cancer studies have identified a number of mutational signatures associated with point mutations, dinucleotide substitutions, insertions and deletions, and rearrangements, and have established etiologies for a subset of these signatures. However, the mechanisms underlying nearly one-third of all mutational signatures are not yet understood. The signatures with established etiology and those with hitherto unknown origin appear to have some differences in strand bias, GC content and nucleotide context diversity. It is possible that some of the hitherto ‘unknown’ signatures predominantly occur outside gene regions. While nucleotide contexts might be adequate to establish etiologies of some mutational signatures, in other cases additional features, such as broader (epi)genomic contexts, including chromatin, replication timing, processivity and local mutational patterns, may help fully understand the underlying DNA damage and repair processes. Nonetheless, remarkable progress in characterization of mutational signatures has provided fundamental insights into the biology of cancer, informed disease etiology and opened up new opportunities for cancer prevention, risk management, and therapeutic decision making.

scholarly journals In situ analysis of repair processes for oxidative DNA damage in mammalian cells

2004 ◽  
Vol 101 (38) ◽  
pp. 13738-13743 ◽  
Author(s):  
L. Lan ◽  
S. Nakajima ◽  
Y. Oohata ◽  
M. Takao ◽  
S. Okano ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mammalian Cells ◽  
Oxidative Dna Damage ◽  
In Situ Analysis ◽  
Repair Processes

Interaction between Radiation and Drug Damage in Mammalian Cells. V. DNA Damage and Repair Induced in LZ Cells by Adriamycin and/or Radiation

1991 ◽  
Vol 126 (1) ◽  
pp. 80 ◽  
Author(s):  
Marguerite A. Sognier ◽  
Richard L. Eberle ◽  
Yin Zhang ◽  
James A. Belli
Keyword(s):  
Dna Damage ◽  
Mammalian Cells ◽  
Dna Damage And Repair

scholarly journals Interaction between Fibroblasts and Immune Cells Following DNA Damage Induced by Ionizing Radiation

2020 ◽  
Author(s):  
Kalaiyarasi Ragunathan ◽  
Nikki Lyn Esnardo Upfold ◽  
Valentyn Oksenych
Keyword(s):  
Dna Damage ◽  
Tumor Microenvironment ◽  
Ionizing Radiation ◽  
Immune Cells ◽  
Mammalian Cells ◽  
Cancer Associated Fibroblasts ◽  
Cell Type ◽  
Dna Damages ◽  
Damage Response ◽  
High Doses

Cancer-associated fibroblasts (CAF) form the basis of tumor microenvironment and possess immunomodulatory functions by interacting with other cells surrounding tumor, including T lymphocytes, macrophages, dendritic cells and natural killer cells. Ionizing radiation is a broadly-used method in radiotherapy to target tumors. In mammalian cells, ionizing radiation induces various types of DNA damages and DNA damage response. Being unspecific, radiotherapy affects all the cells in tumor microenvironment, including the tumor itself, CAFs and immune cells. CAFs are extremely radio-resistant and do not initiate apoptosis even at high doses of radiation. However, following radiation, CAFs become senescent and produce a distinct combination of immunoregulatory molecules. Radiosensitivity of immune cells varies depending on the cell type due to inefficient DNA repair in, for example, monocytes and granulocytes. In this minireview, we are summarizing recent findings on the interaction between CAF, ionizing radiation and immune cells in the tumor microenvironment.

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