1
|
Zaharieva EK, Sasatani M, Kamiya K. Kinetics of DNA Repair Under Chronic Irradiation at Low and Medium Dose Rates in Repair Proficient and Repair Compromised Normal Fibroblasts. Radiat Res 2021; 197:332-349. [PMID: 34958666 DOI: 10.1667/rade-21-00158.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 11/17/2021] [Indexed: 11/03/2022]
Abstract
We present time and dose dependencies for the formation of 53BP1 and γH2AX DNA damage repair foci after chronic radiation exposure at dose rates of 140, 250 and 450 mGy/day from 3 to 96 h, in human and mouse repair proficient and ATM or DNA-PK deficient repair compromised cell models. We describe the time/dose-response curves using a mathematical equation which contains a linear component for the induction of DNA damage repair foci after irradiation, and an exponential component for their resolution. We show that under conditions of chronic irradiation at low and medium dose rates, the processes of DNA double-strand breaks (DSBs) induction and repair establish an equilibrium, which in repair proficient cells manifests as a plateau-shaped dose-response where the plateau is reached within the first 24 h postirradiation, and its height is proportionate to the radiation dose rate. In contrast, in repair compromised cells, where the rate of repair may be exceeded by the DSB induction rate, DNA damage accumulates with time of exposure and total absorbed dose. In addition, we discuss the biological meaning of the observed dependencies by presenting the frequency of micronuclei formation under the same irradiation conditions as a marker of radiation-induced genomic instability. We believe that the data and analysis presented here shed light on the kinetics of DNA repair under chronic radiation and are useful for future studies in the low-to-medium dose rate range.
Collapse
Affiliation(s)
- Elena K Zaharieva
- Department of Experimental Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Megumi Sasatani
- Department of Experimental Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Kenji Kamiya
- Department of Experimental Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| |
Collapse
|
2
|
Sayed AEDH, Nagata K, Nakazawa T, Mitani H, Kobayashi J, Oda S. Low Dose-Rate Irradiation of Gamma-Rays-Induced Cytotoxic and Genotoxic Alterations in Peripheral Erythrocytes of p53-Deficient Medaka (Oryzias latipes). FRONTIERS IN MARINE SCIENCE 2021. [DOI: 10.3389/fmars.2021.773481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Morphological alterations and nuclear abnormalities in fish erythrocytes have been used in many studies as bioindicators of environmental mutagens including ionizing radiation. In this study, adult Japanese medaka (Oryzias latipes) were irradiated with gamma rays at a low dose rate (9.92 μGy/min) for 7 days, giving a total dose of 100 mGy; and morphological alterations, nuclear abnormalities, and apoptotic cell death induced in peripheral erythrocytes were investigated 8 h and 7 days after the end of the irradiation. A variety of abnormalities, such as tear-drop cell, crenated cell, acanthocyte, sickled cell, micronucleated cell, eccentric nucleus, notched nucleus, and schistocyte, were induced in the peripheral erythrocytes of the wild-type fish, and a less number of abnormalities and apoptotic cell death were induced in the p53-deficient fish. These results indicate that low dose-rate chronic irradiation of gamma rays can induce cytotoxic and genotoxic effects in the peripheral erythrocytes of medaka, and p53-deficient medaka are tolerant to the gamma-ray irradiation than the wild type on the surface.
Collapse
|
3
|
Meng Q, Zaharieva EK, Sasatani M, Kobayashi J. Possible relationship between mitochondrial changes and oxidative stress under low dose-rate irradiation. Redox Rep 2021; 26:160-169. [PMID: 34435550 PMCID: PMC8405122 DOI: 10.1080/13510002.2021.1971363] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Objectives: High dose-rate ionizing radiation (IR) causes severe DSB damage, as well as reactive oxygen species (ROS) accumulation and oxidative stress. However, it is unknown what biological processes are affected by low dose-rate IR; therefore, the molecular relationships between mitochondria changes and oxidative stress in human normal cells was investigated after low dose-rate IR.Methods: We compared several cellular response between high and low dose-rate irradiation using cell survival assay, ROS/RNS assay, immunofluorescence and western blot analysis.Results: Reduced DSB damage and increased levels of ROS, with subsequent oxidative stress responses, were observed in normal cells after low dose-rate IR. Low dose-rate IR caused several mitochondrial changes, including morphology mass, and mitochondrial membrane potential, suggesting that mitochondrial damage was caused. Although damaged mitochondria were removed by mitophagy to stop ROS leakage, the mitophagy-regulatory factor, PINK1, was reduced following low dose-rate IR. Although mitochondrial dynamics (fission/fusion events) are important for the proper mitophagy process, some mitochondrial fusion factors decreased following low dose-rate IR.Discussion: The dysfunction of mitophagy pathway under low dose-rate IR increased ROS and the subsequent activation of the oxidative stress response.
Collapse
Affiliation(s)
- Qingmei Meng
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Sciences, Kyoto University, Yoshidanihonmatsucho, Sakyo-ku, Kyoto, Japan
| | - Elena Karamfilova Zaharieva
- Department of Experimental Oncology, Research Institute for Radiation Biology and Medicine (RIRBM), Hiroshima University, Hiroshima, Japan
| | - Megumi Sasatani
- Department of Experimental Oncology, Research Institute for Radiation Biology and Medicine (RIRBM), Hiroshima University, Hiroshima, Japan
| | - Junya Kobayashi
- Department of Interdisciplinary Environment, Graduate School of Human and Environmental Sciences, Kyoto University, Yoshidanihonmatsucho, Sakyo-ku, Kyoto, Japan
- Department of Radiological Sciences, School of Health Sciences at Narita, International University of Health and Welfare, Narita, Japan
| |
Collapse
|
4
|
Lazzari G, Buono G, Zannino B, Silvano G. Breast Cancer Adjuvant Radiotherapy in BRCA1/2, TP53, ATM Genes Mutations: Are There Solved Issues? BREAST CANCER-TARGETS AND THERAPY 2021; 13:299-310. [PMID: 34012291 PMCID: PMC8126701 DOI: 10.2147/bctt.s306075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/21/2021] [Indexed: 01/08/2023]
Abstract
BRCA1, BRCA2, TP53 and ATM gene mutations are the most studied tumour suppressor genes (TSGs) influencing the loco-regional approach to breast cancer (BC). Due to altered radio sensitivity of mutated cancer cells, mastectomy has always been advised in most patients with BC linked to TSGs mutations in order to avoid or minimize the use of adjuvant radiotherapy (ART). Whether ART is safe or not in these carriers is still debated. As a result, this issue has been widely discussed in the recent ASTRO and ASCO papers, yielding important and useful recommendations on the use of ART according to the mutational status. In this review, we have highlighted the impact of these mutations on local control, toxicities, second tumors, and contralateral breast cancers (CBCs) after ART to solve remaining doubts and encourage the safe use of ART when indicated.
Collapse
Affiliation(s)
- Grazia Lazzari
- Radiation Oncology Unit, San Giuseppe Moscati Hospital, Taranto, 74100, Italy
| | - Giuseppe Buono
- Medical Oncology Unit, San Rocco Hospital, Sessa Aurunca, Caserta, 81037, Italy
| | - Benedetto Zannino
- Medical Oncology Unit, San Rocco Hospital, Sessa Aurunca, Caserta, 81037, Italy
| | - Giovanni Silvano
- Radiation Oncology Unit, San Giuseppe Moscati Hospital, Taranto, 74100, Italy
| |
Collapse
|
5
|
Liu W, Xiu N, Zhao J, Zhao L. Enhanced therapeutic effect of transcatheter arterial chemoembolization combined with radioactive I-125 seed implantation on liver cancer. Oncol Lett 2020; 20:2493-2498. [PMID: 32782568 DOI: 10.3892/ol.2020.11765] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/30/2020] [Indexed: 12/30/2022] Open
Abstract
The present study aimed to evaluate the therapeutic effect of transcatheter arterial chemoembolization (TACE) combined with radioactive I-125 (iodine-125) seed implantation on liver cancer. A total of 38 liver cancer patients in the combined treatment group were treated with lobaplatin-TACE combined with radioactive I-125 seed implantation, while 45 patients in the TACE group were treated only with lobaplatin-TACE. Patients were followed up for survival time, and the liver function, change in α-fetoprotein (AFP) and side effects were evaluated. The average survival time of patients was 6.1 months in the TACE group and 8.2 months in the combined treatment group, and the overall survival was significantly different between the two groups (P<0.05). The response rate of lesions in the combined treatment group was superior to that observed in the TACE group, and the change in AFP in the TACE group was smaller than that in the combined treatment group. Improvement in the effects on most liver function indices in the combined treatment group were better than those in the TACE group. In addition, there were no differences in the side effects experienced between the two groups. Results of this study indicate that the effect of TACE combined with radioactive I-125 seed implantation is superior to that of TACE alone for the treatment of liver cancer, which can further benefit patients.
Collapse
Affiliation(s)
- Wenbao Liu
- Department of Intervention Therapy, Laiyang Central Hospital, Yantai, Shandong 265200, P.R. China
| | - Nanguang Xiu
- Department of Intervention Therapy, Laiyang Central Hospital, Yantai, Shandong 265200, P.R. China
| | - Jinwei Zhao
- Department of Intervention Therapy, Laiyang Central Hospital, Yantai, Shandong 265200, P.R. China
| | - Lianhao Zhao
- Department of Intervention Therapy, Laiyang Central Hospital, Yantai, Shandong 265200, P.R. China
| |
Collapse
|
6
|
Abstract
PURPOSE It was first suggested more than 40 years ago that heterozygous carriers for the human autosomal recessive disorder Ataxia-Telangiectasia (A-T) might also be at increased risk for cancer. Subsequent studies have identified the responsible gene, Ataxia-Telangiectasia Mutated (ATM), characterized genetic variation at this locus in A-T and a variety of different cancers, and described the functions of the ATM protein with regard to cellular DNA damage responses. However, an overall model of how ATM contributes to cancer risk, and in particular, the role of DNA damage in this process, remains lacking. This review considers these questions in the context of contralateral breast cancer (CBC). CONCLUSIONS Heterozygous carriers of loss of function mutations in ATM that are A-T causing, are at increased risk of breast cancer. However, examination of a range of genetic variants, both rare and common, across multiple cancers, suggests that ATM may have additional effects on cancer risk that are allele-dependent. In the case of CBC, selected common alleles at ATM are associated with a reduced incidence of CBC, while other rare and predicted deleterious variants may act jointly with radiation exposure to increase risk. Further studies that characterize germline and somatic ATM mutations in breast cancer and relate the detected genetic changes to functional outcomes, particularly with regard to radiation responses, are needed to gain a complete picture of the complex relationship between ATM, radiation and breast cancer.
Collapse
Affiliation(s)
- Jonine L Bernstein
- a Department of Epidemiology and Biostatistics , Memorial Sloan Kettering Cancer Center , New York , NY , U.S.A
| | | | - Patrick Concannon
- b Genetics Institute and Department of Pathology, Immunology and Laboratory Medicine , University of Florida , Gainesville , FL , U.S.A
| |
Collapse
|
7
|
Iodine-125 Brachytherapy Prophylaxis after Radiofrequency Ablation Cannot Benefit Patients in High Risk of Locoregional Hepatocellular Carcinoma Recurrence. Sci Rep 2017. [PMID: 28623296 PMCID: PMC5473839 DOI: 10.1038/s41598-017-03831-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study evaluated if iodine-125 brachytherapy prophylaxis after radiofrequency ablation (RFA) prolongs time to recurrence (TTR) and overall survival (OS) of patients in high risk of locoregional hepatocellular carcinoma (HCC) recurrence. 116 patients with total tumor necrosis after RFA were divided into iodine-125 brachytherapy prophylaxis treatment group and control group. The primary endpoint was TTR, and secondary endpoints were OS and treatment-related adverse events. There were no significant differences among the baseline characteristics of two subgroups patients. The mean iodine-125 particles were 29.8 (26.59 ± 12.51 mCi) per patient. The mean follow-up was 25 months, and mean TTR of treatment and control groups were 21.7 and 15.9 months (P = 0.733); mean OS of two subgroups were 41.7 and 40.9 months (P = 0.316). There were no significant differences of 1-, 2-, 3-, 4-and 5-years TTR and OS and patients’ immunity pre- and 1 month post-treatment. Extrahepatic metastasis was found to have a statistically significant influence on TTR, and AFP, extrahepatic metastasis were found to have a statistically significant influence on OS by multivariate analysis. There was no major complications and procedure related death. Iodine-125 brachytherapy prophylaxis after RFA can’t improve TTR and OS of HCC patients who were in high risk of locoregional tumor recurrence.
Collapse
|
8
|
Low-dose irradiation prior to bone marrow transplantation results in ATM activation and increased lethality in Atm-deficient mice. Bone Marrow Transplant 2016; 51:560-7. [PMID: 26752140 DOI: 10.1038/bmt.2015.334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 11/29/2015] [Accepted: 12/01/2015] [Indexed: 11/08/2022]
Abstract
Ataxia telangiectasia is a genetic instability syndrome characterized by neurodegeneration, immunodeficiency, severe bronchial complications, hypersensitivity to radiotherapy and an elevated risk of malignancies. Repopulation with ATM-competent bone marrow-derived cells (BMDCs) significantly prolonged the lifespan and improved the phenotype of Atm-deficient mice. The aim of the present study was to promote BMDC engraftment after bone marrow transplantation using low-dose irradiation (IR) as a co-conditioning strategy. Atm-deficient mice were transplanted with green fluorescent protein-expressing, ATM-positive BMDCs using a clinically relevant non-myeloablative host-conditioning regimen together with TBI (0.2-2.0 Gy). IR significantly improved the engraftment of BMDCs into the bone marrow, blood, spleen and lung in a dose-dependent manner, but not into the cerebellum. However, with increasing doses, IR lethality increased even after low-dose IR. Analysis of the bronchoalveolar lavage fluid and lung histochemistry revealed a significant enhancement in the number of inflammatory cells and oxidative damage. A delay in the resolution of γ-H2AX-expression points to an insufficient double-strand break repair capacity following IR with 0.5 Gy in Atm-deficient splenocytes. Our results demonstrate that even low-dose IR results in ATM activation. In the absence of ATM, low-dose IR leads to increased inflammation, oxidative stress and lethality in the Atm-deficient mouse model.
Collapse
|
9
|
Peng S, Yang QX, Zhang T, Lu MJ, Yang G, Liu ZY, Zhang R, Zhang FJ. Lobaplatin-TACE combined with radioactive 125I seed implantation for treatment of primary hepatocellular carcinoma. Asian Pac J Cancer Prev 2015; 15:5155-60. [PMID: 25040967 DOI: 10.7314/apjcp.2014.15.13.5155] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the efficacy and safety of lobaplatin-transcatheter arterial chemoembolization (TACE) combined with radioactive 125I seed implantation in treatment of primary hepatocellular carcinoma (HCC). METHODS 75 patients with primary HCC were enrolled in the study, among them 43 receiving lobaplatin- TACE (TACE group) and 32 lobaplatin-TACE combined with 125I seed implantation (TACE+125I group). After treatment, the local remission rates and postoperative complications of two groups were compared using the Pearson Chi-square test. Overall survival in the two groups was calculated using Kaplan-Meier survival curves and the differences were tested using Log-rank test. RESULTS There were 7 cases of complete response (CR), 13 of partial response (PR), 6 of stable disease (SD) and 17 of progressive disease (PD) in the TACE group, with 13 cases of CR, 9 of PR, 5 of SD and 5 of PD in the TACE+125I group. The disease control rates of TACE and TACE+125I group were 60.5% (26/43) and 84.4% (27/32), respectively, with a significant difference between them (P < 0.05). The survival rates at 6, 12 and 18 months in the TACE group were 100.0%, 81.8% and 50.0%, respectively, and those in TACE+125I group were 100.0%, 93.8% and 65.6%. The mean survival times in the TACE and TACE+125I groups were 19.5 and 22.9 months, respectively. There was a significant difference in the overall survival rate between two groups (P < 0.05). No serious complications were encountered in either group. CONCLUSION Lobaplatin-TACE combined with 125I seed implantation is favorable and safe for treatment of primary HCC.
Collapse
Affiliation(s)
- Sheng Peng
- Department of Medical Imaging and Minimally Invasive Interventional Center; Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, Guangzhou, China E-mail :
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Takabayashi K, Kashiwagi K, Kawata T, Sato T, Matsuoka K, Hisamatsu T, Takaishi H, Hibi T, Ogata H, Yahagi N, Kitagawa Y, Shigematsu N, Kanai T. Continuous low-dose irradiation by I-125 seeds induces apoptosis of gastric cancer cells regardless of histological origin. Cancer Biol Ther 2013; 15:81-8. [PMID: 24149371 DOI: 10.4161/cbt.26610] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The efficacy of conventional radiation therapy for gastric cancer is controversial. In this study, we evaluated the in vitro and in vivo effects of continuous low-dose-rate irradiation by I-125 seeds on different histological types of gastric cancer cell lines. Three human gastric cancer cell lines (MKN74, MKN45, and NUGC4) were treated with or without continuous low-dose irradiation by I-125 seeds in vitro and in vivo. Cell viability, apoptosis, caspase-3 assay, and cell-cycle distribution were examined in vitro. Body weight and tumor volumes of BALB/c nude mice bearing MKN74, MKN45, and NUGC4 gastric cancer xenografts were measured, and in vivo cell proliferation and apoptosis assays were performed by Ki67 and TUNEL staining, respectively. Continuous low-dose-rate irradiation by I-125 seeds reduced cell viability and induced cell apoptosis through the activation of caspase-3, and led to the accumulation of cells in the G 2/M phase in vitro. It also suppressed the growth of gastric cancer xenografts in nude mice, while inhibiting cell proliferation and inducing apoptosis as demonstrated by Ki67 and TUNEL staining. Therefore, our data suggest that continuous low-dose-rate irradiation by I-125 seeds could be a promising new option for gastric cancer treatment, regardless of histological origin.
Collapse
Affiliation(s)
- Kaoru Takabayashi
- Division of Gastroenterology and Hepatology; Department of Internal Medicine; School of Medicine; Keio University; Tokyo, Japan
| | - Kazuhiro Kashiwagi
- Center for Diagnostic and Therapeutic Endoscopy; School of Medicine; Keio University; Tokyo, Japan
| | - Tetsuya Kawata
- Department of Radiology; School of Medicine; Keio University; Tokyo, Japan
| | - Toshiro Sato
- Division of Gastroenterology and Hepatology; Department of Internal Medicine; School of Medicine; Keio University; Tokyo, Japan
| | - Katsuyoshi Matsuoka
- Division of Gastroenterology and Hepatology; Department of Internal Medicine; School of Medicine; Keio University; Tokyo, Japan
| | - Tadakazu Hisamatsu
- Division of Gastroenterology and Hepatology; Department of Internal Medicine; School of Medicine; Keio University; Tokyo, Japan
| | | | - Toshifumi Hibi
- Division of Gastroenterology and Hepatology; Department of Internal Medicine; School of Medicine; Keio University; Tokyo, Japan
| | - Haruhiko Ogata
- Center for Diagnostic and Therapeutic Endoscopy; School of Medicine; Keio University; Tokyo, Japan
| | - Naohisa Yahagi
- Division of Research and Development for Minimally Invasive Treatment; Cancer Center; School of Medicine; Keio University; Tokyo, Japan
| | - Yuko Kitagawa
- Department of Surgery; School of Medicine; Keio University; Tokyo, Japan
| | - Naoyuki Shigematsu
- Department of Radiology; School of Medicine; Keio University; Tokyo, Japan
| | - Takanori Kanai
- Division of Gastroenterology and Hepatology; Department of Internal Medicine; School of Medicine; Keio University; Tokyo, Japan
| |
Collapse
|
11
|
Sugihara T, Murano H, Tanaka K. Increased γ-H2A.X intensity in response to chronic medium-dose-rate γ-ray irradiation. PLoS One 2012; 7:e45320. [PMID: 23028931 PMCID: PMC3445451 DOI: 10.1371/journal.pone.0045320] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 08/21/2012] [Indexed: 12/31/2022] Open
Abstract
Background The molecular mechanisms of DNA repair following chronic medium-dose-rate (MDR) γ-ray-induced damage remain largely unknown. Methodology/Principal Findings We used a cell function imager to quantitatively measure the fluorescence intensity of γ-H2A.X foci in MDR (0.015 Gy/h and 0.06 Gy/h) or high-dose-rate (HDR) (54 Gy/h) γ-ray irradiated embryonic fibroblasts derived from DNA-dependent protein kinase mutated mice (scid/scid mouse embryonic fibroblasts (scid/scid MEFs)). The obtained results are as follows: (1) Automatic measurement of the intensity of radiation-induced γ-H2A.X foci by the cell function imager provides more accurate results compared to manual counting of γ-H2A.X foci. (2) In high-dose-rate (HDR) irradiation, γ-H2A.X foci with high fluorescence intensity were observed at 1 h after irradiation in both scid/scid and wild-type MEFs. These foci were gradually reduced through de-phosphorylation at 24 h or 72 h after irradiation. Furthermore, the fluorescence intensity at 24 h increased to a significantly greater extent in scid/scid MEFs than in wild-type MEFs in the G1 phase, although no significant difference was observed in G2/M-phase MEFs, suggesting that DNA-PKcs might be associated with non-homologous-end-joining-dependent DNA repair in the G1 phase following HDR γ-ray irradiation. (3) The intensity of γ-H2A.X foci for continuous MDR (0.06 Gy/h and 0.015 Gy/h) irradiation increased significantly and in a dose-dependent fashion. Furthermore, unlike HDR-irradiated scid/scid MEFs, the intensity of γ-H2A.X foci in MDR-irradiated scid/scid MEFs showed no significant increase in the G1 phase at 24 h, indicating that DNA repair systems using proteins other than DNA-PKcs might induce cell functioning that are subjected to MDR γ-ray irradiation. Conclusions Our results indicate that the mechanism of phosphorylation or de-phosphorylation of γ-H2A.X foci induced by chronic MDR γ-ray irradiation might be different from those induced by HDR γ-ray irradiation.
Collapse
Affiliation(s)
- Takashi Sugihara
- Department of Radiobiology, Institute for Environmental Sciences, Rokkasho, Kamikita, Aomori, Japan.
| | | | | |
Collapse
|
12
|
Shimada M, Kobayashi J, Hirayama R, Komatsu K. Differential role of repair proteins, BRCA1/NBS1 and Ku70/DNA-PKcs, in radiation-induced centrosome overduplication. Cancer Sci 2010; 101:2531-7. [PMID: 20825415 PMCID: PMC11159506 DOI: 10.1111/j.1349-7006.2010.01702.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Centrosomes are important cytoplasmic organelles involved in chromosome segregation, defects in which can result in aneuploidy, and contribute to tumorigenesis. It is known that DNA damage causes the supernumerary centrosomes by a mechanism in which centrosomes continue to duplicate during cell cycle arrest at checkpoints. We show here that ionizing radiation induces the overduplication of centrosomes in a dose-dependent manner, and that the level of overduplication is pronounced in BRCA1- and NBS1-deficient cells, even though their checkpoint control is abrogated. Conversely, marginal increases in overduplication were observed in Ku70- and DNA-PKcs-deficient cells, which are intact in checkpoint control. The frequency of radiation-induced overduplication of centrosomes might be associated with DNA repair, as it was decreased with reduced cell killing after protracted exposures to radiation. As a result, when the frequency of radiation-induced centrosome overduplication was plotted against radiation-induced cell killing, similar curves were seen for both protracted and acute exposures in wild-type cells, Ku70-deficient, and DNA-PKcs-deficient cells, indicating a common mechanism for centrosome overduplication. However, the absence of either BRCA1 or NBS1 enhanced radiation-induced overduplication frequencies by 2-4-fold on the basis of the same cell killing. These results suggest that radiation-induced centrosome overduplication is regulated by at least two mechanisms: a checkpoint-dependent pathway involved in wild-type cells, Ku70-deficient and DNA-PKcs-deficient cells; and a checkpoint-independent pathway as observed in BRCA1-deficient and NBS1-deficient cells.
Collapse
Affiliation(s)
- Mikio Shimada
- Radiation Biology Center, Kyoto University, Kyoto, Japan
| | | | | | | |
Collapse
|
13
|
Sato K, Nishikino M, Okano Y, Ohshima S, Hasegawa N, Ishino M, Kawachi T, Numasaki H, Teshima T, Nishimura H. γ-H2AX and phosphorylated ATM focus formation in cancer cells after laser plasma X irradiation. Radiat Res 2010; 174:436-45. [PMID: 20718602 DOI: 10.1667/rr2178.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The usefulness of laser plasma X-ray pulses for medical and radiation biological studies was investigated, and the effects of laser plasma X rays were compared with those of conventional sources such as a linear accelerator. A cell irradiation system was developed that used copper-Kα (8 keV) lines from an ultrashort high-intensity laser to produce plasma. The absorbed dose of the 8 keV laser plasma X-ray pulse was estimated accurately with Gafchromic® EBT film. When the cells were irradiated with approximately 2 Gy of laser plasma X rays, the circular regions on γ-H2AX-positive cells could be clearly identified. Moreover, the numbers of γ-H2AX and phosphorylated ataxia telangiectasia mutated (ATM) foci induced by 8 keV laser plasma X rays were comparable to those induced by 4 MV X rays. These results indicate that the laser plasma X ray source may be useful for radiation biology studies.
Collapse
Affiliation(s)
- Katsutoshi Sato
- Department of Medical Physics and Engineering, Graduated School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka 565-0871, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Kitajima S, Nakamura H, Adachi M, Ijichi K, Yasui Y, Saito N, Suzuki M, Kurita K, Ishizaki K. AT cells show dissimilar hypersensitivity to heavy-ion and X-rays irradiation. JOURNAL OF RADIATION RESEARCH 2010; 51:251-255. [PMID: 20197645 DOI: 10.1269/jrr.09069] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Ataxia telangiectasia (AT) cells, with their defective double-strand break (DSB) repair processes, exhibit high sensitivity to low-LET radiation such as X-rays irradiation and gamma beams. Since heavy ion beam treatment for cancer is becoming increasingly common in Japan and elsewhere, it is important to also determine their sensitivity to high-LET radiation. For this purpose we irradiated AT and normal human cells immortalized with the human telomerase gene using high- (24-60 keV/microm carbon and 200 keV/microm iron ions) or low-LET (X-rays) radiation in non-proliferative conditions. In normal cells the RBE (relative biological effectiveness) of carbon and iron ions increased from 1.19 to 1.81 in proportion to LET. In contrast, their RBE in AT cells increased from 1.32 at 24 keV/microm to 1.59 at 40 keV/microm, and exhibited a plateau at over 40 keV/microm. In normal cells most gamma-H2AX foci induced by both carbon- and iron-ion beams had disappeared at 40 h. In AT cells, however, a significant number of gamma-H2AX foci were still observed at 40 h. The RBEs found in the AT cells after heavy-ion irradiation were consistent with the effects predicted from the presence of non-homologous end joining defects. The DSBs remaining after heavy-ion irradiation suggested defects in the AT cells' DSB repair ability.
Collapse
Affiliation(s)
- Shoichiro Kitajima
- Central Laboratory and Radiation Biology, Aichi Cancer Center Research Institute, Nagoya 464-8681, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Liao A, Wang J, Wang J, Zhuang H, Zhao Y. Relative biological effectiveness and cell-killing efficacy of continuous low-dose-rate 125I seeds on prostate carcinoma cells in vitro. Integr Cancer Ther 2010; 9:59-65. [PMID: 20150222 DOI: 10.1177/1534735409357758] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The aim of this study was to determine the effects of (125)I seeds on prostate carcinoma (PC3) cells. The relative biological effectiveness of (125)I seeds on PC3 cells with respect to (60)Co gamma rays was 1.4. Both 4 Gy of (60)Co gamma ray and (125)I seed irradiation increased the percentage of cells in G(2) phase, but there was no significant difference between these 2 types of radiation. Significantly, (125)I seeds induced higher apoptotic rates of PC3 cells compared with (60)Co gamma ray irradiation. Furthermore, Bcl-2 expression, but not caspase-3 activity, in PC3 cells was downregulated after irradiation with (125)I seed or (60)Co gamma rays.
Collapse
Affiliation(s)
- Anyan Liao
- Peking University 3rd Hospital. Beijing, China
| | | | | | | | | |
Collapse
|
16
|
Zhuang HQ, Wang JJ, Liao AY, Wang JD, Zhao Y. The biological effect of 125I seed continuous low dose rate irradiation in CL187 cells. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2009; 28:12. [PMID: 19175942 PMCID: PMC2655271 DOI: 10.1186/1756-9966-28-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 01/29/2009] [Indexed: 11/29/2022]
Abstract
Background To investigate the effectiveness and mechanism of 125I seed continuous low-dose-rate irradiation on colonic cell line CL187 in vitro. Methods The CL187 cell line was exposed to radiation of 60Coγ ray at high dose rate of 2 Gy/min and 125I seed at low dose rate of 2.77 cGy/h. Radiation responses to different doses and dose rates were evaluated by colony-forming assay. Under 125I seed low dose rate irradiation, a total of 12 culture dishes were randomly divided into 4 groups: Control group, and 2, 5, and 10 Gy irradiation groups. At 48 h after irradiation, apoptosis was detected by Annexin and Propidium iodide (PI) staining. Cell cycle arrests were detected by PI staining. In order to investigate the influence of low dose rate irradiation on the MAPK signal transduction, the expression changes of epidermal growth factor receptor (EGFR) and Raf under continuous low dose rate irradiation (CLDR) and/or EGFR monoclonal antibodies were determined by indirect immunofluorescence. Results The relative biological effect (RBE) for 125I seeds compared with 60Co γ ray was 1.41. Apoptosis rates of CL187 cancer cells were 13.74% ± 1.63%, 32.58% ± 3.61%, and 46.27% ± 3.82% after 2 Gy, 5 Gy, and 10 Gy irradiation, respectively; however, the control group apoptosis rate was 1.67% ± 0.19%. G2/M cell cycle arrests of CL187 cancer cells were 42.59% ± 3.21%, 59.84% ± 4.96%, and 34.61% ± 2.79% after 2 Gy, 5 Gy, and 10 Gy irradiation, respectively; however, the control group apoptosis rate was 26.44% ± 2.53%. P < 0.05 vs. control groups by Student's t-test were found in every treated group both in apoptosis and in G2/M cell cycle arrest. After low dose rate irradiation, EGFR and Raf expression increased, but when EGFR was blocked by a monoclonal antibody, EGFR and Raf expression did not change. Conclusion 125I seeds resulted in more effective inhibition than 60Co γ ray high dose rate irradiation in CL187 cells. Apoptosis following G2/M cell cycle arrest was the main mechanism of cell-killing effects under low dose rate irradiation. CLDR could influence the proliferation of cells via MAPK signal transduction.
Collapse
Affiliation(s)
- Hong-Qing Zhuang
- Cancer Center, Department of Radiation Oncology, Peking University Third Hospital, Beijing 100191, PR China.
| | | | | | | | | |
Collapse
|
17
|
Low-Dose Hyper-Radiosensitivity: Past, Present, and Future. Int J Radiat Oncol Biol Phys 2008; 70:1310-8. [DOI: 10.1016/j.ijrobp.2007.11.071] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/27/2007] [Accepted: 11/30/2007] [Indexed: 01/07/2023]
|
18
|
Nakamura H. hTERT-immortalized cells useful for analyzing effects of low-dose-rate radiation on human cells. JOURNAL OF RADIATION RESEARCH 2008; 49:9-15. [PMID: 18160772 DOI: 10.1269/jrr.07088] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
To establish immortal human cells, we introduced the cDNA of the human telomere reverse transcriptase (hTERT) gene into skin fibroblast cells obtained from normal and ataxia telangiectasia (AT) individuals of Japanese origin. hTERT-immortalized cells retained their original characteristics and radiosensitivity except for immortalization, suggesting that these cells might be useful for analyzing the effects of radiation on human cells.hTERT-immortalized cells from a normal individual showed a greater resistance after low-dose-rate irradiation than after high-dose-rate irradiation. In contrast, cells from AT patients irradiated at a low-dose rate showed virtually the same survival as those irradiated at a high-dose rate. In hTERT-immortalized normal cells, the genetic effects of low-dose-rate radiation were quantitatively and qualitatively less severe than those of high-dose-rate radiation. In hTERT-immortalized AT cells, some fraction of DNA damage such as DNA double-strand breaks might not be repaired, and AT cells were severely affected by low-dose-rate radiation. The activation of ataxia telangiectasia mutated (ATM) protein was confirmed during low-dose-rate radiation, and may play an important role in repair of DNA damage induced by low-dose-rate radiation. This paper reviews briefly the current research at our laboratory. The hTERT-immortalized cells may be useful in determining the effects of low-dose and low-dose-rate radiation on human cells.
Collapse
Affiliation(s)
- Hideaki Nakamura
- Central Laboratory and Radiation Biology, Aichi Cancer Center Research Institute, Nagoya, Japan.
| |
Collapse
|
19
|
Day TK, Hooker AM, Zeng G, Sykes PJ. Low dose X-radiation adaptive response in spleen and prostate of Atm knockout heterozygous mice. Int J Radiat Biol 2007; 83:523-34. [PMID: 17613125 DOI: 10.1080/09553000701420582] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE To investigate the effect of being heterozygous for a knockout mutation in the ataxia telangiectasia (Atm) gene on radiation adaptive response. MATERIALS AND METHODS DNA recombination, as measured by pKZ1 inversion frequency, was quantified by histochemistry in Atm knockout heterozygous prostate and spleen 3 days after treatment with a priming dose of 0.01 or 10 mGy X-radiation 4 h prior to a challenge dose of 1,000 mGy. RESULTS In spleen and prostate, a single dose of 0.01 mGy caused an induction in inversion frequency but a dose of 10 mGy prevented the induction of a proportion of endogenous inversions. Both doses induced an adaptive response, of similar magnitude, to a subsequent high challenge dose for chromosomal inversions in both spleen and prostate. The adaptive response completely prevented the induction of inversions from a 1,000 mGy challenge dose and also a proportion of endogenous inversions. The adaptive responses and distribution of inversions across gland cross-sections observed here in Atm knockout heterozygote prostate were similar to those induced in Atm wild-type prostate in a previous study. CONCLUSIONS Being heterozygous for a knockout mutation in the Atm gene does not affect the endogenous pKZ1 inversion frequency, the inversion response to single low radiation doses used here, or the induction of a radiation adaptive response for inversions in pKZ1 mouse spleen or prostate.
Collapse
Affiliation(s)
- Tanya K Day
- Department of Haematology and Genetic Pathology, Flinders University and Medical Centre, Bedford Park, South Australia, Australia
| | | | | | | |
Collapse
|