1
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Verma N, Tiku AB. Role of mTOR pathway in modulation of radiation induced bystander effects. Int J Radiat Biol 2021; 98:173-182. [PMID: 34855567 DOI: 10.1080/09553002.2022.2013567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE Radiation-induced bystander effect (RIBE) is considered as an important consequence of radiation exposure. Based on the type of effect induced, it has important implications in radiation therapy. mTOR pathway, a key regulator of cell survival, plays an important role in radiation-induced damages. However, the role of mTOR signaling in the modulation of RIBE is still unclear. We evaluated the role of mTOR pathway in RIBE and its relationship with the radiation response of target cells. MATERIALS AND METHODS Direct and bystander effects were evaluated by using clonogenic and MTT assay in five different cell lines. Expression of mTOR pathway proteins in directly targeted and bystander cells was studied using western blotting. RESULTS Among five different cell lines naïve HT1080 and A549 cells exhibited proliferative bystander effect induced by conditioned media and irradiated conditioned media, while no effect was observed in other cell lines. Everolimus significantly abolished the proliferative bystander effect induced in naïve cells. CONCLUSIONS These results suggested that the mTOR pathway plays an important role in RIBEs. These effects are cell type-specific and depending on the radiosensitivity of the target cells, therapeutic benefits of radiation may be modulated by treatment with mTOR inhibitors.
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Affiliation(s)
- Neha Verma
- Radiation and Cancer Therapeutics Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Ashu Bhan Tiku
- Radiation and Cancer Therapeutics Lab, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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2
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Leu JD, Wang CY, Lo CC, Lin MY, Chang CY, Hung WC, Lin ST, Wang BS, Lee YJ. Involvement of c-Myc in low dose radiation-induced senescence enhanced migration and invasion of unirradiated cancer cells. Aging (Albany NY) 2021; 13:22208-22231. [PMID: 34552037 PMCID: PMC8507273 DOI: 10.18632/aging.203527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 08/11/2021] [Indexed: 12/27/2022]
Abstract
Ionizing radiation is known to cause cell apoptosis at high dose range, but little is known about the cellular response to low dose radiation. In this study, we found that conditioned medium harvested from WI-38 lung fibroblasts and H1299 lung adenocarcinoma cells exposed to 0.1Gy to 1Gy could enhance the migration and invasion of unirradiated H1299 cells in both 2D and 3D culturing circumstances. Low dose radiation did not induce apoptosis, but induced senescence in irradiated cells. We next examined the expression of immediately early genes including c-Myc and K-Ras. Although both genes could be up-regulated by low dose radiation, induction of c-Myc was more specific to low dose range (0.5Gy) at transcriptional and translational levels. Knockdown of c-Myc by shRNA could repress the senescence induced by low dose radiation. The conditioned medium of irradiated cells induced migration of unirradiated cells was also repressed by knockdown of c-Myc. The c-Myc inhibitor 10058-F4 could suppress low dose radiation induced cell senescence, and the conditioned medium harvested from irradiated cells pretreated with 10058-F4 also lost the ability to enhance the migration of unirradiated cells. The cytokine array analysis revealed that immunosuppressive monocyte chemoattractant protein-1 increased by low dose radiation could be repressed by 10058-F4. We also showed that 10058-F4 could suppress low dose radiation induced tumor progression in a xenograft tumor model. Taken together, current data suggest that -Myc is involved in low dose radiation induced cell senescence and potent bystander effect to increase the motility of unirradiated cells.
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Affiliation(s)
- Jyh-Der Leu
- Department of Radiation Oncology, Taipei City Hospital, Taipei 110, Taiwan.,Institute of Neuroscience, National Cheng Chi University, Taipei 116, Taiwan
| | - Chung-Yih Wang
- Radiotherapy, Department of Medical Imaging, Cheng Hsin General Hospital, Taipei 112, Taiwan
| | - Chia-Chien Lo
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Min-Ying Lin
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Chun-Yuan Chang
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan.,Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, NJ 08903-2681, USA
| | - Wen-Chin Hung
- Department of Radiation Oncology, Taipei City Hospital, Taipei 110, Taiwan
| | - Shi-Ting Lin
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Bo-Shen Wang
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Yi-Jang Lee
- Department of Radiation Oncology, Taipei City Hospital, Taipei 110, Taiwan.,Cancer Progression Research Center, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
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3
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Ilyas AM, Alam MK, Musah JD, Yang M, Roy VAL, Lam YW, Lau C. CHO cell dysfunction due to radiation-induced bystander signals observed by real-time electrical impedance measurement. Biosens Bioelectron 2021; 181:113142. [PMID: 33752028 DOI: 10.1016/j.bios.2021.113142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/22/2021] [Accepted: 03/01/2021] [Indexed: 11/30/2022]
Abstract
Radiation-induced bystander effects (RIBE) have raised many concerns about radiation safety and protection. In RIBE, unirradiated cells receive signals from irradiated cells and exhibit irradiation effects. Until now, most RIBE studies have been based on morphological and biochemical characterization. However, research on the impact of RIBE on biophysical properties of cells has been lagging. Non-invasive indium tin oxide (ITO)-based impedance systems have been used as bioimpedance sensors for monitoring cell behaviors. This powerful technique has not been applied to RIBE research. In this work, we employed an electrical cell-ITO substrate impedance system (ECIIS) to study the RIBE on Chinese hamster ovary (CHO) cells. The bioimpedance of bystander CHO cells (BCHO), alpha(α)-particle (Am-241) irradiated CHO (ICHO), and untreated/unirradiated CHO (UCHO) cells were monitored with a sampling interval of 8 s over a period of 24 h. Media from ICHO cells exposed to different radiation doses (0.3 nGy, 0.5 nGy, and 0.7 nGy) were used to investigate the radiation dose dependence of BCHO cells' impedance. In parallel, we imaged the cells at times where impedance changes were observed. By analyzing the changes in absolute impedance and cell size/cell number with time, we observed that BCHO cells mimicked ICHO cells in terms of modification in cell morphology and proliferation rate. Furthermore, these effects appeared to be time-dependent and inversely proportional to the radiation dose. Hence, this approach allows a label-free study of cellular responses to RIBE with high sensitivity and temporal resolution and can provide crucial insights into the RIBE mechanism.
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Affiliation(s)
- A M Ilyas
- Department of Physics, City University of Hong Kong, Kowloon 999077, Hong Kong, China; Department of Physics, Federal University Oye-Ekiti, Ekiti State 3600001, Nigeria.
| | - Md Kowsar Alam
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon 999077, Hong Kong, China; Department of Physics, University of Chittagong, Chittagong 4331, Bangladesh
| | - Jamal-Deen Musah
- Department of Material Science and Engineering, State Key Laboratory of Terahertz and Millimeter Waves, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Mengsu Yang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Vellaisamy A L Roy
- James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Yun Wah Lam
- Department of Chemistry, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Condon Lau
- Department of Physics, City University of Hong Kong, Kowloon 999077, Hong Kong, China
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Jooyan N, Goliaei B, Bigdeli B, Faraji-Dana R, Zamani A, Entezami M, Mortazavi SMJ. Direct and indirect effects of exposure to 900 MHz GSM radiofrequency electromagnetic fields on CHO cell line: Evidence of bystander effect by non-ionizing radiation. ENVIRONMENTAL RESEARCH 2019; 174:176-187. [PMID: 31036329 DOI: 10.1016/j.envres.2019.03.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 02/13/2019] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
INTRODUCTION The rapid rise in global concerns about the adverse health effects of exposure to radiofrequency radiation (RFR) generated by common devices such as mobile phones has prompted scientists to further investigate the biological effects of these environmental exposures. Non-targeted effects (NTEs) are responses which do not need a direct exposure to be expressed and are particularly significant at low energy radiations. Although NTEs of ionizing radiation are well documented, there are scarcely any studies on non-targeted responses such as bystander effect (BE) after exposure to non-ionizing radiation. The main goal of this research is to study possible RFR-induced BE. MATERIAL AND METHODS Chinese hamster ovary cells were exposed to 900 MHz GSM RFR at an average specific absorption rate (SAR) of 2 W/kg for 4, 12 and 24 hours (h). To generate a uniformly distributed electromagnetic field and avoid extraneous RF exposures a cavity was desined and used. Cell membrane permeability, cell redox activity, metabolic and mitotic cell death and DNA damages were analyzed. Then the most effective exposure durations and statistically significant altered parameters were chosen to assess the induction of BE through medium transfer procedure. Furthermore, intra and extra cellular reactive oxygen species (ROS) levels were measured to assess the molecular mechanism of BE induced by non-ionizing radiation. RESULTS No statistically significant alteration was found in cell membrane permeability, cell redox activity, metabolic cell activity and micronuclei (MN) frequency in the cells directly exposed to RFR for 4, 12, or 24 h. However, RFR exposure for 24 h caused a statistically significant decrease in clonogenic ability as well as a statistically significant increase in olive moment in both directly exposed and bystander cells which received media from RFR-exposed cells (conditioned culture medium; CCM). Exposure to RFR also statistically significant elevated both intra and extra cellular levels of ROS. CONCLUSION Our observation clearly indicated the induction of BE in cells treated with CCM. To our knowledge, this is the first report that a non-ionizing radiation (900 MHz GSM RFR) can induce bystander effect. As reported for ionizing radiation, our results proposed that ROS can be a potential molecule in indirect effect of RFR. On the other hand, we found the importance of ROS in direct effect of RFR but in different ways.
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Affiliation(s)
- Najmeh Jooyan
- Department of Biophysics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Bahram Goliaei
- Department of Biophysics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
| | - Bahareh Bigdeli
- Department of Biophysics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Reza Faraji-Dana
- School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
| | - Ali Zamani
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Milad Entezami
- School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
| | - Seyed Mohammad Javad Mortazavi
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran; Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC), Shiraz University of Medical Sciences, Shiraz, Iran; Department of Diagnostic Imaging, Fox Chase Cancer Center, 333 Cottman Ave, Philadelphia, PA, 19111, USA.
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Mukherjee S, Chakraborty A. Radiation-induced bystander phenomenon: insight and implications in radiotherapy. Int J Radiat Biol 2019; 95:243-263. [PMID: 30496010 DOI: 10.1080/09553002.2019.1547440] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sharmi Mukherjee
- Stress biology Lab, UGC-DAE Consortium for Scientific Research, Kolkata Centre, Kolkata, West Bengal, India
| | - Anindita Chakraborty
- Stress biology Lab, UGC-DAE Consortium for Scientific Research, Kolkata Centre, Kolkata, West Bengal, India
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Tubin S, Ahmed MM, Gupta S. Radiation and hypoxia-induced non-targeted effects in normoxic and hypoxic conditions in human lung cancer cells. Int J Radiat Biol 2018; 94:199-211. [PMID: 29293036 DOI: 10.1080/09553002.2018.1422085] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE Many cell lines with anaerobic metabolism do not show cytotoxic abscopal effect (AE) following irradiation. Further, there is no existing data on the radiation- and hypoxia (H)-induced AE. The purpose of this study was to investigate and compare the status of radiation-induced abscopal effect (RIAE) in normoxic and hypoxic conditions. METHODS Lung cancer cells (A549, H460) were exposed either to hypoxia or normoxia and then irradiated (2 or 10 Gy). After 24 h, unirradiated hypoxic (H-CM) or normoxic (N-CM) conditioned media (CM) and irradiated hypoxic (H-RCM) or normoxic (N-RCM) CM was collected. Hypoxia-resistant clones (HR: A549/HR, H460/HR) were generated by continuous exposure of the cells to hypoxia. Unirradiated parental cells or HR were exposed to H-CM, N-CM, H-RCM or N-RCM. In some groups, 24 h after exposure to CM, cells were directly irradiated with 2 Gy. Cell growth was monitored using real-time cell electronic sensing system. Further, levels of hypoxia and HIF1α regulated angiogenesis related growth factors, basic fibroblast growth factor (bFGF), placental growth factor (PlGF), soluble fms-like tyrosine kinase (sFlt-1) and vascular endothelial growth factor (VEGF) were assessed in CM. RESULTS In the radio-resistant A549 cells, H-RCM was much more effective in inducing growth delay compared to N-RCM. In the radio-sensitive H460 cells, both N-RCM and H-RCM induced growth delay. Interestingly, effects of N-RCM were completely reversed in HR cells. Exposure of cells to direct irradiation (2 Gy) 24 h after incubation with CM resulted in 50-60% reduction in cell proliferation in A549/HR cells and a very significant induction of death (>95%) in H460/HR cells. Direct irradiation of parental or HR clones of A549 and H460 cells exposed to H-CM 24 h with 2 Gy induced significant reduction in cell proliferation (from 40% to >95%) in all the cells. Further, levels of sFlt-1 correlated with growth delay in all the cells. CONCLUSIONS These results for the first time demonstrate that irradiation of hypoxic cells and exposing the cells to acute hypoxia lead to significant AE.
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Affiliation(s)
- Slavisa Tubin
- a Department of Radiation Oncology , Sylvester Comprehensive Cancer Center, University of Miami Leonard Miller School of Medicine , Miami , FL , USA
| | - Mansoor M Ahmed
- b Division of Cancer Treatment and Diagnosis , National Cancer Institute, National Institutes of Health, Radiotherapy Development Branch, Radiation Research Program , Rockville , MD , USA
| | - Seema Gupta
- a Department of Radiation Oncology , Sylvester Comprehensive Cancer Center, University of Miami Leonard Miller School of Medicine , Miami , FL , USA
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7
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Bahreyni Toossi MT, Khademi S, Azimian H, Mohebbi S, Soleymanifard S. Assessment of The Dose-Response Relationship of Radiation-Induced Bystander Effect in Two Cell Lines Exposed to High Doses of Ionizing Radiation (6 and 8 Gy). CELL JOURNAL 2017; 19:434-442. [PMID: 28836405 DOI: 10.22074/cellj.2017.4343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/11/2016] [Indexed: 11/04/2022]
Abstract
OBJECTIVES The dose-response relationship of radiation-induced bystander effect (RIBE) is controversial at high dose levels. The aim of the present study is to assess RIBE at high dose levels by examination of different endpoints. MATERIALS AND METHODS This experimental study used the medium transfer technique to induce RIBE. The cells were divided into two main groups: QU-DB cells which received medium from autologous irradiated cells and MRC5 cells which received medium from irradiated QU-DB cells. Colony, MTT, and micronucleus assays were performed to quantify bystander responses. The medium was diluted and transferred to bystander cells to investigate whether medium dilution could revive the RIBE response that disappeared at a high dose. RESULTS The RIBE level in QU-DB bystander cells increased in the dose range of 0.5 to 4 Gy, but decreased at 6 and 8 Gy. The Micronucleated cells per 1000 binucleated cells (MNBN) frequency of QU-DB bystander cells which received the most diluted medium from 6 and 8 Gy QU-DB irradiated cells reached the maximum level compared to the MNBN frequency of the cells that received complete medium (P<0.0001). MNBN frequency of MRC5 cells which received the most diluted medium from 4 Gy QU-DB irradiated cells reached the maximum level compared to MNBN frequency of cells that received complete medium (P<0.0001). CONCLUSIONS Our results showed that RIBE levels decreased at doses above 4 Gy; however, RIBE increased when diluted conditioned medium was transferred to bystander cells. This finding confirmed that a negative feedback mechanism was responsible for the decrease in RIBE response at high doses. Decrease of RIBE at high doses might be used to predict that in radiosurgery, brachytherapy and grid therapy, in which high dose per fraction is applied, normal tissue damage owing to RIBE may decrease.
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Affiliation(s)
- Mohammad Taghi Bahreyni Toossi
- Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Sara Khademi
- Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Hosein Azimian
- Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Shokoufeh Mohebbi
- Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Shokouhozaman Soleymanifard
- Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Medical Physics, Omid Hospital, Mashhad, Iran.
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8
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Significance and nature of bystander responses induced by various agents. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:104-121. [DOI: 10.1016/j.mrrev.2017.05.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/05/2017] [Indexed: 02/07/2023]
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9
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Baskar R, Itahana K. Radiation therapy and cancer control in developing countries: Can we save more lives? Int J Med Sci 2017; 14:13-17. [PMID: 28138304 PMCID: PMC5278654 DOI: 10.7150/ijms.17288] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 11/01/2016] [Indexed: 01/25/2023] Open
Abstract
Globally, morbidity and mortality due to cancer are predicted to increase in both men and women in the coming decades. Furthermore, it is estimated that two thirds of these cancer-related deaths will occur in low-and middle-income countries (LMIC). In addition to morbidity and mortality, cancer also causes an enormous economic burden, especially in developing countries. There are several treatment and management options for cancer including chemotherapy, radiation therapy, surgery, and palliative care. Radiotherapy or radiation therapy (RT) can be an effective treatment, especially for localized or solid cancers; about half of cancer patients receive radiation as a curative or palliative treatment. Because of its low cost, for patients from LMIC with inoperable tumors, RT may be the only option. With the overall increase in the number of cancer patients especially in resource-starved LMIC, the need for more RT facilities further affects the economic growth of those countries. Therefore, an advanced molecular-targeted and more integrated approach involving either RT alone or with surgery and improved cancer drug access worldwide are urgent needs for cancer care.
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Affiliation(s)
| | - Koji Itahana
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore
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10
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Tu W, Dong C, Konishi T, Kobayashi A, Furusawa Y, Uchihori Y, Xie Y, Dang B, Li W, Shao C. G(2)-M phase-correlative bystander effects are co-mediated by DNA-PKcs and ATM after carbon ion irradiation. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 795:1-6. [PMID: 26774662 DOI: 10.1016/j.mrgentox.2015.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 10/30/2015] [Accepted: 11/05/2015] [Indexed: 10/22/2022]
Abstract
Accumulated evidence has shown that radiation-induced bystander effect (RIBE) may have significant implications to the efficiency of radiotherapy. Although cellular radiosensitivity relies on cell cycle status, it is largely unknown how about the relationship between RIBE and cell cycle distribution, much less the underlying mechanism. In the present study, the lung cancer A549 cells were synchronized into different cell cycle phases of G1, S and G2/M and irradiated with high linear energy transfer (LET) carbon ions. By treating nonirradiated cells with the conditioned medium from these irradiated cells, it was found that the G2-M phase cells had the largest contribution to RIBE. Meanwhile, the activity of DNA-PKcs but not ATM was increased in the synchronized G2-M phase cells in spite of both of them were activated in the asynchronous cells after carbon ion irradiation. When the G2-M phased cells were transferred with DNA-PKcs siRNA and ATM siRNA individually or treated with an inhibitor of either DNA-PKcs or ATM before carbon ion irradiation, the RIBE was effectively diminished. These results provide new evidence linking cell cycle to bystander responses and demonstrate that DNA-PKcs and ATM are two associated factors in co-regulating G2-M phase-related bystander effects.
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Affiliation(s)
- Wenzhi Tu
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
| | - Chen Dong
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China
| | - Teruaki Konishi
- Research Development and Support Center, National Institute of Radiological Sciences, Inage, Chiba 263-8555, Japan
| | - Alisa Kobayashi
- Research Development and Support Center, National Institute of Radiological Sciences, Inage, Chiba 263-8555, Japan
| | - Yoshiya Furusawa
- Research Development and Support Center, National Institute of Radiological Sciences, Inage, Chiba 263-8555, Japan
| | - Yukio Uchihori
- Research Development and Support Center, National Institute of Radiological Sciences, Inage, Chiba 263-8555, Japan
| | - Yuexia Xie
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China; Central Laboratory of Renji Hospital, Shanghai Jiaotong University, Shanghai 200001, China
| | - Bingrong Dang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Wenjian Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Chunlin Shao
- Institute of Radiation Medicine, Fudan University, Shanghai 200032, China.
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11
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Tomita M, Matsumoto H, Funayama T, Yokota Y, Otsuka K, Maeda M, Kobayashi Y. Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation. LIFE SCIENCES IN SPACE RESEARCH 2015; 6:36-43. [PMID: 26256626 DOI: 10.1016/j.lssr.2015.06.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 06/04/2023]
Abstract
In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time after irradiation.
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Affiliation(s)
- Masanori Tomita
- Radiation Safety Research Center, Central Research Institute of Electric Power Industry, 2-11-1 Iwado Kita, Komae, Tokyo 201-8511, Japan.
| | - Hideki Matsumoto
- Division of Oncology, Biomedical Imaging Research Center, University of Fukui, 23-3 Matsuoka-Shimoaitsuki, Eiheiji-cho, Fukui 910-1193, Japan
| | - Tomoo Funayama
- Microbeam Radiation Biology Group, Radiation Biology Research Division, Quantum Beam Science Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan
| | - Yuichiro Yokota
- Microbeam Radiation Biology Group, Radiation Biology Research Division, Quantum Beam Science Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan
| | - Kensuke Otsuka
- Radiation Safety Research Center, Central Research Institute of Electric Power Industry, 2-11-1 Iwado Kita, Komae, Tokyo 201-8511, Japan
| | - Munetoshi Maeda
- Radiation Safety Research Center, Central Research Institute of Electric Power Industry, 2-11-1 Iwado Kita, Komae, Tokyo 201-8511, Japan; Proton Medical Research Group, Research and Development Department, The Wakasa Wan Energy Research Center, 64-52-1 Nagatani, Tsuruga-shi, Fukui 914-0192, Japan
| | - Yasuhiko Kobayashi
- Microbeam Radiation Biology Group, Radiation Biology Research Division, Quantum Beam Science Center, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292, Japan
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Tomita M, Maeda M. Mechanisms and biological importance of photon-induced bystander responses: do they have an impact on low-dose radiation responses. JOURNAL OF RADIATION RESEARCH 2015; 56:205-19. [PMID: 25361549 PMCID: PMC4380047 DOI: 10.1093/jrr/rru099] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 09/19/2014] [Accepted: 09/29/2014] [Indexed: 06/01/2023]
Abstract
Elucidating the biological effect of low linear energy transfer (LET), low-dose and/or low-dose-rate ionizing radiation is essential in ensuring radiation safety. Over the past two decades, non-targeted effects, which are not only a direct consequence of radiation-induced initial lesions produced in cellular DNA but also of intra- and inter-cellular communications involving both targeted and non-targeted cells, have been reported and are currently defining a new paradigm in radiation biology. These effects include radiation-induced adaptive response, low-dose hypersensitivity, genomic instability, and radiation-induced bystander response (RIBR). RIBR is generally defined as a cellular response that is induced in non-irradiated cells that receive bystander signals from directly irradiated cells. RIBR could thus play an important biological role in low-dose irradiation conditions. However, this suggestion was mainly based on findings obtained using high-LET charged-particle radiations. The human population (especially the Japanese, who are exposed to lower doses of radon than the world average) is more frequently exposed to low-LET photons (X-rays or γ-rays) than to high-LET charged-particle radiation on a daily basis. There are currently a growing number of reports describing a distinguishing feature between photon-induced bystander response and high-LET RIBR. In particular, photon-induced bystander response is strongly influenced by irradiation dose, the irradiated region of the targeted cells, and p53 status. The present review focuses on the photon-induced bystander response, and discusses its impact on the low-dose radiation effect.
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Affiliation(s)
- Masanori Tomita
- Radiation Safety Research Center, Central Research Institute of Electric Power Industry, 2-11-1 Iwado Kita, Komae, Tokyo 201-8511, Japan
| | - Munetoshi Maeda
- Radiation Safety Research Center, Central Research Institute of Electric Power Industry, 2-11-1 Iwado Kita, Komae, Tokyo 201-8511, Japan Proton Medical Research Group, Research and Development Department, The Wakasa Wan Energy Research Center, 64-52-1 Nagatani, Tsuruga-shi, Fukui 914-0192, Japan
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Tubin S, Valeriani M, Salerno G, Bracci S, Stoppacciaro A, Cardelli P, Osti MF, De Sanctis V, Minniti G, Maurizi Enrici R. Manipulation of radiation-induced bystander effect in prostate adenocarcinoma by dose and tumor differentiation grade: in vitro study. Int J Radiat Biol 2015; 91:166-71. [PMID: 25174735 DOI: 10.3109/09553002.2015.959667] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE This in vitro study evaluated the ability of prostate adenocarcinoma (ADC) cells to induce radiation-induced bystander effect (RIBE) exploring the factors that may be responsible and affect its intensity. The idea was to mimic a strong, clinically applicable RIBE that could lead to the development of innovative approaches in modern radiotherapy of prostate cancer, especially for those patients with hormone-refractory ADC in which radiotherapy might have a limited role. MATERIALS AND METHODS Two human prostate cancer cell lines of different differentiation, PC-3 and DU-145, have been irradiated using wide range of doses to obtain radiation-conditioned medium (RCM), which was used to treat the unirradiated cells and to evaluate the cytokines level. Using a trypan blue dye exclusion method, cell growth was assessed. RESULTS Prostate ADC cells were able to induce RIBE; intensity depended on dose and cell differentiation. RIBE intensity of DU-145 was not correlated with the cytokines level, while for PC-3 Interleukin-6 (IL-6) correlates with strongest RIBE induced by 20 Gy. CONCLUSIONS RIBE can be manipulated by modifying radiation dose and depends on cell differentiation status. IL-6 correlates with RIBE after exposure of PC-3 to a very high dose of radiation, thus indicates its possible involvement in bystander signaling.
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Affiliation(s)
- Slavisa Tubin
- "La Sapienza" University, Sant' Andrea Hospital, Radiation Oncology , Rome , Italy
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Dai J, Itahana K, Baskar R. Quiescence does not affect p53 and stress response by irradiation in human lung fibroblasts. Biochem Biophys Res Commun 2015; 458:104-9. [PMID: 25637534 DOI: 10.1016/j.bbrc.2015.01.076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 01/17/2015] [Indexed: 01/17/2023]
Abstract
Cells in many organs exist in both proliferating and quiescent states. Proliferating cells are more radio-sensitive, DNA damage pathways including p53 pathway are activated to undergo either G1/S or G2/M arrest to avoid entering S and M phase with DNA damage. On the other hand, quiescent cells are already arrested in G0, therefore there may be fundamental difference of irradiation response between proliferating and quiescent cells, and this difference may affect their radiosensitivity. To understand these differences, proliferating and quiescent human normal lung fibroblasts were exposed to 0.10-1 Gy of γ-radiation. The response of key proteins involved in the cell cycle, cell death, and metabolism as well as histone H2AX phosphorylation were examined. Interestingly, p53 and p53 phosphorylation (Ser-15), as well as the cyclin-dependent kinase inhibitors p21 and p27, were induced similarly in both proliferating and quiescent cells after irradiation. Furthermore, the p53 protein half-life, and expression of cyclin A, cyclin E, proliferating cell nuclear antigen (PCNA), Bax, or cytochrome c expression as well as histone H2AX phosphorylation were comparable after irradiation in both phases of cells. The effect of radioprotection by a glycogen synthase kinase 3β inhibitor on p53 pathway was also similar between proliferating and quiescent cells. Our results showed that quiescence does not affect irradiation response of key proteins involved in stress and DNA damage at least in normal fibroblasts, providing a better understanding of the radiation response in quiescent cells, which is crucial for tissue repair and regeneration.
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Affiliation(s)
- Jiawen Dai
- Molecular Radiobiology Laboratory, Division of Cellular and Molecular Research, Singapore
| | - Koji Itahana
- Cancer and Stem Cell Biology Program, Duke-NUS Graduate Medical School, Singapore.
| | - Rajamanickam Baskar
- Molecular Radiobiology Laboratory, Division of Cellular and Molecular Research, Singapore; Department of Radiation Oncology, National Cancer Centre, Singapore.
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Baskar R, Dai J, Wenlong N, Yeo R, Yeoh KW. Biological response of cancer cells to radiation treatment. Front Mol Biosci 2014; 1:24. [PMID: 25988165 PMCID: PMC4429645 DOI: 10.3389/fmolb.2014.00024] [Citation(s) in RCA: 336] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/31/2014] [Indexed: 12/15/2022] Open
Abstract
Cancer is a class of diseases characterized by uncontrolled cell growth and has the ability to spread or metastasize throughout the body. In recent years, remarkable progress has been made toward the understanding of proposed hallmarks of cancer development, care, and treatment modalities. Radiation therapy or radiotherapy is an important and integral component of cancer management, mostly conferring a survival benefit. Radiation therapy destroys cancer by depositing high-energy radiation on the cancer tissues. Over the years, radiation therapy has been driven by constant technological advances and approximately 50% of all patients with localized malignant tumors are treated with radiation at some point in the course of their disease. In radiation oncology, research and development in the last three decades has led to considerable improvement in our understanding of the differential responses of normal and cancer cells. The biological effectiveness of radiation depends on the linear energy transfer (LET), total dose, number of fractions and radiosensitivity of the targeted cells or tissues. Radiation can either directly or indirectly (by producing free radicals) damages the genome of the cell. This has been challenged in recent years by a newly identified phenomenon known as radiation induced bystander effect (RIBE). In RIBE, the non-irradiated cells adjacent to or located far from the irradiated cells/tissues demonstrate similar responses to that of the directly irradiated cells. Understanding the cancer cell responses during the fractions or after the course of irradiation will lead to improvements in therapeutic efficacy and potentially, benefitting a significant proportion of cancer patients. In this review, the clinical implications of radiation induced direct and bystander effects on the cancer cell are discussed.
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Affiliation(s)
- Rajamanickam Baskar
- Division of Cellular and Molecular Research, Department of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - Jiawen Dai
- Division of Cellular and Molecular Research, Department of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - Nei Wenlong
- Division of Cellular and Molecular Research, Department of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - Richard Yeo
- Division of Cellular and Molecular Research, Department of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - Kheng-Wei Yeoh
- Division of Cellular and Molecular Research, Department of Radiation Oncology, National Cancer Centre Singapore, Singapore
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Kiuru A, Kämäräinen M, Heinävaara S, Pylkäs K, Chapman K, Koivistoinen A, Parviainen T, Winqvist R, Kadhim M, Launonen V, Lindholm C. Assessment of targeted and non-targeted responses in cells deficient in ATM function following exposure to low and high dose X-rays. PLoS One 2014; 9:e93211. [PMID: 24681528 PMCID: PMC3969311 DOI: 10.1371/journal.pone.0093211] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 03/03/2014] [Indexed: 12/05/2022] Open
Abstract
Radiation sensitivity at low and high dose exposure to X-rays was investigated by means of chromosomal aberration (CA) analysis in heterozygous ATM mutation carrier and A-T patient (biallelic ATM mutation) lymphoblastoid cell lines (LCLs). Targeted and non-targeted responses to acutely delivered irradiation were examined by applying a co-culture system that enables study of both directly irradiated cells and medium-mediated bystander effects in the same experimental setting. No indication of radiation hypersensitivity was observed at doses of 0.01 Gy or 0.1 Gy for the ATM mutation carrier LCL. The A-T patient cells also did not show low-dose response. There was significant increase in unstable CA yields for both ATM mutation carrier and A-T LCLs at 1 and 2 Gy, the A-T cells displaying more distinct dose dependency. Both chromosome and chromatid type aberrations were induced at an increased rate in the irradiated A-T cells, whereas for ATM carrier cells, only unstable chromosomal aberrations were increased above the level observed in the wild type cell line. No bystander effect could be demonstrated in any of the cell lines or doses applied. Characteristics typical for the A-T cell line were detected, i.e., high baseline frequency of CA that increased with dose. In addition, dose-dependent loss of cell viability was observed. In conclusion, CA analysis did not demonstrate low-dose (≤100 mGy) radiosensitivity in ATM mutation carrier cells or A-T patient cells. However, both cell lines showed increased radiosensitivity at high dose exposure.
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Affiliation(s)
- Anne Kiuru
- STUK-Radiation and Nuclear Safety Authority, Helsinki, Finland
| | | | | | - Katri Pylkäs
- Laboratory of Cancer Genetics and Tumor Biology, Department of Clinical Chemistry and Biocenter Oulu, University of Oulu, Oulu University Hospital, Oulu, Finland
| | | | | | | | - Robert Winqvist
- Laboratory of Cancer Genetics and Tumor Biology, Department of Clinical Chemistry and Biocenter Oulu, University of Oulu, Oulu University Hospital, Oulu, Finland
| | | | - Virpi Launonen
- STUK-Radiation and Nuclear Safety Authority, Helsinki, Finland
| | - Carita Lindholm
- STUK-Radiation and Nuclear Safety Authority, Helsinki, Finland
- * E-mail:
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Chandna S, Dagur RS, Mathur A, Natarajan AT, Harms-Ringdahl M, Haghdoost S. Agarose overlay selectively improves macrocolony formation and radiosensitivity assessment in primary fibroblasts. Int J Radiat Biol 2014; 90:401-6. [PMID: 24527670 DOI: 10.3109/09553002.2014.894650] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Primary fibroblasts are not suitable for in vitro macrocolony assay due to their inability to form distinct colonies. Here we present a modification of agarose overlay that yielded extensive improvement in their colony formation and assessment of radiosensitivity. MATERIALS AND METHODS Macrocolony formation was assessed in primary human fibroblasts VH10 and HDFn with or without overlay using 0.5% agarose in growth medium at 24 h post-seeding. Malignant human cell lines (A549, U87) and transformed non-malignant fibroblasts (AA8 hamster, MRC5 human) were used for comparison. RESULTS Agarose overlay caused significant improvement marked by early appearance (one week) of distinct colonies with high cell density and multifold higher plating efficiency than conventional macrocolony assay in VH10 and HDFn human fibroblasts. Compared to conventional assay or feeder cell supplementation, agarose overlay resulted in broader cell morphology due to improved adherence, and yielded more compact colonies. Gamma-radiation dose-response survival curves could be successfully generated for both fibroblast cell lines using this method, which yielded no such effects in the transformed/malignant cell lines tested. CONCLUSION This easy and inexpensive 'agarose overlay technique' significantly and selectively improves the fibroblast plating efficiency, thus considerably reducing time and effort to greatly benefit the survival studies on primary fibroblasts.
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Affiliation(s)
- Sudhir Chandna
- Natural Radiation Response Mechanisms Group, Division of Radiation Biosciences, Institute of Nuclear Medicine & Allied Sciences (INMAS) , Delhi , India
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Mechanisms of radiation toxicity in transformed and non-transformed cells. Int J Mol Sci 2013; 14:15931-58. [PMID: 23912235 PMCID: PMC3759894 DOI: 10.3390/ijms140815931] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 12/31/2022] Open
Abstract
Radiation damage to biological systems is determined by the type of radiation, the total dosage of exposure, the dose rate, and the region of the body exposed. Three modes of cell death—necrosis, apoptosis, and autophagy—as well as accelerated senescence have been demonstrated to occur in vitro and in vivo in response to radiation in cancer cells as well as in normal cells. The basis for cellular selection for each mode depends on various factors including the specific cell type involved, the dose of radiation absorbed by the cell, and whether it is proliferating and/or transformed. Here we review the signaling mechanisms activated by radiation for the induction of toxicity in transformed and normal cells. Understanding the molecular mechanisms of radiation toxicity is critical for the development of radiation countermeasures as well as for the improvement of clinical radiation in cancer treatment.
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Sokolov MV, Panyutin IG, Neumann RD. Whole-genome gene expression profiling reveals the major role of nitric oxide in mediating the cellular transcriptional response to ionizing radiation in normal human fibroblasts. Genomics 2012; 100:277-81. [PMID: 22814268 PMCID: PMC3483410 DOI: 10.1016/j.ygeno.2012.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 04/26/2012] [Accepted: 07/09/2012] [Indexed: 11/16/2022]
Abstract
The indirect biological effects of ionizing radiation (IR) are thought to be mediated largely by reactive oxygen and nitrogen species (ROS and RNS). However, no data are available on how nitric oxide (NO) modulates the response of normal human cells to IR exposures at the level of the whole transcriptome. Here, we examined the effects of NO and ROS scavengers, carboxy-PTIO and DMSO, on changes in global gene expression in cultured normal human fibroblasts after exposures to gamma-rays, aiming to elucidate the involvement of ROS and RNS in transcriptional response to IR. We found that NO depletion dramatically affects the gene expression in normal human cells following irradiation with gamma-rays. We observed striking (more than seven-fold) reduction of the number of upregulated genes upon NO scavenging compared to reference irradiated cell cultures. NO scavenging in irradiated IMR-90 cells results in induction of p53 signaling, DNA damage and DNA repair pathways.
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Affiliation(s)
- Mykyta V. Sokolov
- Nuclear Medicine Division, Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland, 20892, United States of America
| | - Igor G. Panyutin
- Nuclear Medicine Division, Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland, 20892, United States of America
| | - Ronald D. Neumann
- Nuclear Medicine Division, Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland, 20892, United States of America
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20
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Cytochrome-c mediated a bystander response dependent on inducible nitric oxide synthase in irradiated hepatoma cells. Br J Cancer 2012; 106:889-95. [PMID: 22274409 PMCID: PMC3305951 DOI: 10.1038/bjc.2012.9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Radiation-induced bystander effect (RIBE) has important implication in tumour radiotherapy, but the bystander signals are still not well known. METHODS The role of cytochrome-c (cyt-c) and free radicals in RIBE on human hepatoma cells HepG2 was investigated by detecting the formation of bystander micronuclei (MN) and the generation of endogenous cyt-c, inducible nitric oxide (NO) synthase (iNOS), NO, and reactive oxygen species (ROS) molecules. RESULTS When HepG2 cells were cocultured with an equal number of irradiated HepG2 cells, the yield of MN in the nonirradiated bystander cells was increased in a manner depended on radiation dose and cell coculture time, but it was diminished when the cells were treated with cyclosporin A (CsA), an inhibitor of cyt-c release. Meanwhile the CsA treatment inhibited radiation-induced NO but not ROS. Both of the depressed bystander effect and NO generation in the CsA-treated cells were reversed when 5 μM cyt-c was added in the cell coculture medium. But these exogenous cyt-c-mediated overproductions of NO and bystander MN were abolished when the cells were pretreated with s-methylisothiourea sulphate, an iNOS inhibitor. CONCLUSION Radiation-induced cyt-c has a profound role in regulating bystander response through an iNOS-triggered NO signal but not ROS in HepG2 cells.
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Blyth BJ, Sykes PJ. Radiation-induced bystander effects: what are they, and how relevant are they to human radiation exposures? Radiat Res 2011; 176:139-57. [PMID: 21631286 DOI: 10.1667/rr2548.1] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The term radiation-induced bystander effect is used to describe radiation-induced biological changes that manifest in unirradiated cells remaining within an irradiated cell population. Despite their failure to fit into the framework of classical radiobiology, radiation-induced bystander effects have entered the mainstream and have become established in the radiobiology vocabulary as a bona fide radiation response. However, there is still no consensus on a precise definition of radiation-induced bystander effects, which currently encompasses a number of distinct signal-mediated effects. These effects are classified here into three classes: bystander effects, abscopal effects and cohort effects. In this review, the data have been evaluated to define, where possible, various features specific to radiation-induced bystander effects, including their timing, range, potency and dependence on dose, dose rate, radiation quality and cell type. The weight of evidence supporting these defining features is discussed in the context of bystander experimental systems that closely replicate realistic human exposure scenarios. Whether the manifestation of bystander effects in vivo is intrinsically limited to particular radiation exposure scenarios is considered. The conditions under which radiation-induced bystander effects are induced in vivo will ultimately determine their impact on radiation-induced carcinogenic risk.
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Affiliation(s)
- Benjamin J Blyth
- Haematology and Genetic Pathology, Flinders University, Bedford Park, South Australia 5042, Australia
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Beaton LA, Burn TA, Stocki TJ, Chauhan V, Wilkins RC. Development and characterization of anin vitroalpha radiation exposure system. Phys Med Biol 2011; 56:3645-58. [DOI: 10.1088/0031-9155/56/12/012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Baskar R. Emerging role of radiation induced bystander effects: Cell communications and carcinogenesis. Genome Integr 2010; 1:13. [PMID: 20831828 PMCID: PMC2949714 DOI: 10.1186/2041-9414-1-13] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 09/12/2010] [Indexed: 02/05/2023] Open
Abstract
Ionizing radiation is an invaluable diagnostic and treatment tool used in various clinical applications. On the other hand, radiation is a known cytotoxic with a potential DNA damaging and carcinogenic effects. However, the biological effects of low and high linear energy transfer (LET) radiations are considerably more complex than previously thought. In the past decade, evidence has mounted for a novel biological phenomenon termed as "bystander effect" (BE), wherein directly irradiated cells transmit damaging signals to non-irradiated cells thereby inducing a response similar to that of irradiated cells. BE can also be induced in various cells irrespective of the type of radiation, and the BE may be more damaging in the longer term than direct radiation exposure. BE is mediated either through gap-junctions or via soluble factors released by irradiated cells. DNA damage response mechanisms represent a vital line of defense against exogenous and endogenous damage caused by radiation and promote two distinct outcomes: survival and the maintenance of genomic stability. The latter is critical for cancer avoidance. Therefore, efforts to understand and modulate the bystander responses will provide new approaches to cancer therapy and prevention. This review overviews the emerging role of BE of low and high LET radiations on the genomic instability of bystander cells and its possible implications for carcinogenesis.
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Affiliation(s)
- Rajamanickam Baskar
- Department of Radiation Oncology, Division of Cellular and Molecular Research, National Cancer Centre, Singapore.
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Jeong S, Marks BP, Ryser ET, Moosekian SR. Inactivation of Escherichia coli O157:H7 on lettuce, using low-energy X-ray irradiation. J Food Prot 2010; 73:547-51. [PMID: 20202343 DOI: 10.4315/0362-028x-73.3.547] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Low-energy X-ray irradiation was assessed as a means of eliminating Escherichia coli O157:H7 on lettuce. Round-cut iceberg lettuce samples (2.54-cm diameter) were dip or spot inoculated with a three-strain cocktail of E. coli O157:H7, stored for 24 h at 4 degrees C, and then irradiated at four dose levels up to 0.25 kGy using a prototype low-energy (70 kV) X-ray irradiator. E. coli O157:H7 survivors were quantified by plating on sorbitol MacConkey agar containing cefixime and tellurite. Dip inoculation yielded a D(10)-value of 0.040 +/- 0.001 kGy, which is 3.4 times lower than a previously reported value of 0.136 kGy using gamma radiation. The D(10)-value for E. coli O157:H7 on spot-inoculated samples was 0.078 +/- 0.008 kGy, which is about twice that of dip-inoculated samples. When 10 stacked leaves were irradiated from both sides, a dose of 0.2 kGy was achieved at the center of the stack with a surface dose of 1 kGy, corresponding to a approximately 5-log reduction of E. coli O157:H7 at the center of the stack. Based on these findings, low-energy X-ray irradiation appears to be a promising microbial inactivation strategy for leafy greens and potentially for other types of fresh produce.
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Affiliation(s)
- Sanghyup Jeong
- Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824, USA.
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Baskar R, Hande MP. A comparative study of protein kinase C activation in gamma-irradiated proliferating and confluent human lung fibroblast cells. JOURNAL OF RADIATION RESEARCH 2009; 50:415-423. [PMID: 19602851 DOI: 10.1269/jrr.08125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Exposure to low doses of radiation has been recently proven to be much more mutagenic and carcinogenic than previously thought. Since radiation sensitivity varies with different phases of cell cycle, we have investigated the activation of protein kinase C (PKC) after low doses (0.10-1 Gy) of gamma-irradiation on proliferating (log) and non-proliferating (confluent/plateau) human normal lung fibroblast (MRC-5) cells. PKC isoforms have been shown to play key roles in the regulation of proliferation, differentiation, migration and survival. In this study, we have examined the activation of phosphorylated forms of PKC isoforms (PKC-betaII, PKC-alpha/beta, PKC-theta) and non-phosphorylated PKC-alpha in an attempt to understand its kinases in total and subcellular (cytosolic and nuclear) fractions. Cytosolic fraction of the log phase cells showed an increase in activity of PKC-betaII, PKC-alpha/beta and PKC-theta with the radiation dose. However, in the nuclear fraction, PKC-betaII and PKC-theta showed higher activity than the PKC-alpha/beta. In the plateau phase cells of the cytosolic fraction, PKC-betaII showed higher activity than the PKC-alpha/beta and PKC-theta isoforms. Furthermore, in the nuclear fraction PKC-betaII and PKC-alpha/beta isoforms showed higher activity than the PKC-theta. In total cellular protein of the log phase cells, a dose dependent increase in PKC-betaII activity followed by PKC-alpha/ beta was observed and in the plateau phase of cells, PKC-betaII showed higher activity than the PKC-alpha/ beta. The specific activation of PKC isoforms in the plateau phase cells, as demonstrated for the first time, may help us to understand the radiation induced initiation of cellular transformation like hyper-proliferative phenotype, if any.
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Affiliation(s)
- Rajamanickam Baskar
- Department of Clinical Research, Singapore General Hospital, Outram Road, Singapore-169608.
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Hu B, Shen B, Su Y, Geard CR, Balajee AS. Protein kinase C epsilon is involved in ionizing radiation induced bystander response in human cells. Int J Biochem Cell Biol 2009; 41:2413-21. [PMID: 19577658 DOI: 10.1016/j.biocel.2009.06.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2009] [Revised: 06/16/2009] [Accepted: 06/29/2009] [Indexed: 12/14/2022]
Abstract
Our earlier study demonstrated the induction of PKC isoforms (betaII, PKC-alpha/beta, PKC-theta) by ionizing radiation induced bystander response in human cells. In this study, we extended our investigation to yet another important member of PKC family, PKC epsilon (PKCepsilon). PKCepsilon functions both as an anti-apoptotic and pro-apoptotic protein and it is the only PKC isozyme implicated in oncogenesis. Given the importance of PKCepsilon in oncogenesis, we wished to determine whether or not PKCepsilon is involved in bystander response. Gene expression array analysis demonstrated a 2-3-fold increase in PKCepsilon expression in the bystander human primary fibroblast cells that were co-cultured in double-sided Mylar dishes for 3h with human primary fibroblast cells irradiated with 5Gy of alpha-particles. The elevated PKCepsilon expression in bystander cells was verified by quantitative real time PCR. Suppression of PKCepsilon expression by small molecule inhibitor Bisindolylmaleimide IX (Ro 31-8220) considerably reduced the frequency of micronuclei (MN) induced both by 5Gy of gamma-rays (low LET) and alpha-particles (high LET) in bystander cells. Similar cytoprotective effects were observed in bystander cells after siRNA mediated silencing of PKCepsilon suggestive of its critical role in mediating some of the bystander effects (BE). Our novel study suggests the possibility that PKC signaling pathway may be a critical molecular target for suppression of ionizing radiation induced biological effects in bystander cells.
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Affiliation(s)
- Burong Hu
- Center for Radiological Research, Department of Radiation Oncology, College of Physicians and Surgeons, 630 West, 168th Street, VC-11, Room 239, Columbia University, New York, NY 10032, USA
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Baskar R, Sparatore A, Del Soldato P, Moore PK. Effect of S-diclofenac, a novel hydrogen sulfide releasing derivative inhibit rat vascular smooth muscle cell proliferation. Eur J Pharmacol 2008; 594:1-8. [DOI: 10.1016/j.ejphar.2008.07.029] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 07/03/2008] [Accepted: 07/10/2008] [Indexed: 12/31/2022]
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Anzenberg V, Chandiramani S, Coderre JA. LET-Dependent Bystander Effects Caused by Irradiation of Human Prostate Carcinoma Cells with X Rays or Alpha Particles. Radiat Res 2008; 170:467-76. [DOI: 10.1667/rr1312.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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