Exposure of Normal Human Fibroblasts to Heavy-Ion Radiation Promotes Their Morphological Differentiation

Sora, Sakura; Hamada, Nobuyuki; Hara, Takamitsu; Funayama, Tomoo; Sakashita, Tetsuya; Yokota, Yuichiro; Nakano, Takashi; Kobayashi, Yasuhiko

doi:10.2187/bss.22.54

Cited by 3 publications

(2 citation statements)

References 20 publications

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“…This can happen as soon as the number of DSBs per nucleus decreases to 10–20 [52]. In cell cultures irradiated with low-LET γ-rays, the cells are arrested for relatively short periods, i.e., about 4 h. For high LET radiation, the arrest is significantly longer than for γ-rays, i.e., about 48 h and more [53,54] or even permanent [55], depending on the LET of the ion-radiation. Thus, for the LET of 15 N as used in the experiments presented here, a checkpoint arrest release can be expected if about 10–15 DSBs remain unrepaired [56].…”

Section: Discussionmentioning

confidence: 99%

Recruitment of 53BP1 Proteins for DNA Repair and Persistence of Repair Clusters Differ for Cell Types as Detected by Single Molecule Localization Microscopy

Bobkova

Depeš

Lee

et al. 2018

IJMS

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DNA double stranded breaks (DSBs) are the most serious type of lesions introduced into chromatin by ionizing radiation. During DSB repair, cells recruit different proteins to the damaged sites in a manner dependent on local chromatin structure, DSB location in the nucleus, and the repair pathway entered. 53BP1 is one of the important players participating in repair pathway decision of the cell. Although many molecular biology details have been investigated, the architecture of 53BP1 repair foci and its development during the post-irradiation time, especially the period of protein recruitment, remains to be elucidated. Super-resolution light microscopy is a powerful new tool to approach such studies in 3D-conserved cell nuclei. Recently, we demonstrated the applicability of single molecule localization microscopy (SMLM) as one of these highly resolving methods for analyses of dynamic repair protein distribution and repair focus internal nano-architecture in intact cell nuclei. In the present study, we focused our investigation on 53BP1 foci in differently radio-resistant cell types, moderately radio-resistant neonatal human dermal fibroblasts (NHDF) and highly radio-resistant U87 glioblastoma cells, exposed to high-LET 15N-ion radiation. At given time points up to 24 h post irradiation with doses of 1.3 Gy and 4.0 Gy, the coordinates and spatial distribution of fluorescently tagged 53BP1 molecules was quantitatively evaluated at the resolution of 10–20 nm. Clusters of these tags were determined as sub-units of repair foci according to SMLM parameters. The formation and relaxation of such clusters was studied. The higher dose generated sufficient numbers of DNA breaks to compare the post-irradiation dynamics of 53BP1 during DSB processing for the cell types studied. A perpendicular (90°) irradiation scheme was used with the 4.0 Gy dose to achieve better separation of a relatively high number of particle tracks typically crossing each nucleus. For analyses along ion-tracks, the dose was reduced to 1.3 Gy and applied in combination with a sharp angle irradiation (10° relative to the cell plane). The results reveal a higher ratio of 53BP1 proteins recruited into SMLM defined clusters in fibroblasts as compared to U87 cells. Moreover, the speed of foci and thus cluster formation and relaxation also differed for the cell types. In both NHDF and U87 cells, a certain number of the detected and functionally relevant clusters remained persistent even 24 h post irradiation; however, the number of these clusters again varied for the cell types. Altogether, our findings indicate that repair cluster formation as determined by SMLM and the relaxation (i.e., the remaining 53BP1 tags no longer fulfill the cluster definition) is cell type dependent and may be functionally explained and correlated to cell specific radio-sensitivity. The present study demonstrates that SMLM is a highly appropriate method for investigations of spatiotemporal protein organization in cell nuclei and how it influences the cell decision for a particular re...

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Section: Discussionmentioning

confidence: 99%

Recruitment of 53BP1 Proteins for DNA Repair and Persistence of Repair Clusters Differ for Cell Types as Detected by Single Molecule Localization Microscopy

Bobkova

Depeš

Lee

et al. 2018

IJMS

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“…Heavy ions are more genotoxic and cytotoxic to directly irradiated cells than low-LET photons like X-rays and γ-rays (Ando and Kase, 2009;Hamada, 2009;Hamada et al, 2010;Fokas et al, 2009). The mode of heavy ion-induced cell death/inactivation includes apoptosis, necrosis, autophagy, premature senescence, accelerated differentiation, together with delayed reproductive death in the progeny of irradiated cells (Al-Jahdari et al, 2009;Blakely and Chang, 2009;Hamada et al, 2006Hamada et al, , 2008aJinno-Oue et al, 2010;Kakizaki et al, 2006Kakizaki et al, , 2007Kawamura et al, 2009;Sora et al, 2008). In addition to LET, the heavy-ion response depends on ion species or ion track structure (Tsuruoka et al, 2005(Tsuruoka et al, , 2008.…”

Section: Introductionmentioning

confidence: 99%

The Bystander Response to Heavy-Ion Radiation: Intercellular Signaling Between Irradiated and Non-Irradiated Cells

Hamada

2009

Biol. Sci. Space

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Ionizing radiation-induced bystander effect is the phenomenon whereby cells that are not themselves irradiated but received signals from directly irradiated cells exhibit biological r e s p o n s e s . H u m a n e x p o s u r e t o h e av y -ion radiation occurs during manned space missions at the dose and dose rate much lower than those for cancer therapy. It should be noted herein that less irradiated cells coexist with more non-irradiated counterparts in a cell population exposed to a lower dose of radiation whose linear energy transfer is higher. The bystander effect should be thence examined to decipher the action mechanism of low-dose heavy ions. The bystander effect of heavy ions is manifested as inactivated clonogenic potential, a transient apoptotic response, delayed p53 phosphorylation, gene expression changes, a transient cell-cycle arrest, chromosome aberrations, elevated mutation fre quency and micronucleation. Proposed underpinning mechanisms involve gap junctional intercellular communication and reactive oxygen/nitrogen species. This paper reviews briefly the current knowledge of the heavy ion-induced bystander effect.The bystander effect of heavy-ion radiation − 196 −

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Recent Insights into the Biological Action of Heavy-Ion Radiation

Hamada

2009

JRR

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Biological effectiveness varies with the linear energy transfer (LET) of ionizing radiation. During cancer therapy or long-term interplanetary manned explorations, humans are exposed to high-LET energetic heavy ions that inactivate cells more effectively than low-LET photons like X-rays and gamma-rays. Recent biological studies have illustrated that heavy ions overcome tumor radioresistance caused by Bcl-2 overexpression, p53 mutations and intratumor hypoxia, and possess antiangiogenic and antimetastatic potential. Compared with heavy ions alone, the combination with chemical agents (a Bcl-2 inhibitor HA14-1, an anticancer drug docetaxel, and a halogenated pyrimidine analogue 5-iodo-2'-deoxyuridine) or hyperthermia further enhances tumor cell killing. Beer, its certain constituents, or melatonin ameliorate heavy ion-induced damage to normal cells. In addition to effects in cells directly targeted with heavy ions, there is mounting evidence for nontargeted biological effects in cells that have not themselves been directly irradiated. The bystander effect of heavy ions manifests itself as the loss of clonogenic potential, a transient apoptotic response, delayed p53 phosphorylation, alterations in gene expression profiles, and the elevated frequency of gene mutations, micronuclei and chromosome aberrations, which arise in nonirradiated cells having received signals from irradiated cells. Proposed mediating mechanisms involve gap junctional intercellular communication, reactive oxygen species and nitric oxide. This paper reviews briefly the current knowledge of the biological effects of heavy-ion irradiation with a focus on recent findings regarding its potential benefits for therapeutic use as well as on the bystander effect.

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Exposure of Normal Human Fibroblasts to Heavy-Ion Radiation Promotes Their Morphological Differentiation

Cited by 3 publications

References 20 publications

Recruitment of 53BP1 Proteins for DNA Repair and Persistence of Repair Clusters Differ for Cell Types as Detected by Single Molecule Localization Microscopy

Recruitment of 53BP1 Proteins for DNA Repair and Persistence of Repair Clusters Differ for Cell Types as Detected by Single Molecule Localization Microscopy

The Bystander Response to Heavy-Ion Radiation: Intercellular Signaling Between Irradiated and Non-Irradiated Cells

Recent Insights into the Biological Action of Heavy-Ion Radiation

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