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Cherednichenko O, Pilyugina A, Nuraliev S, Azizbekova D. Persons chronically exposed to low doses of ionizing radiation: A cytogenetic dosimetry study. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2024; 894:503728. [PMID: 38432778 DOI: 10.1016/j.mrgentox.2024.503728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/10/2024] [Accepted: 01/13/2024] [Indexed: 03/05/2024]
Abstract
The dosimetry and control of exposure for individuals chronically exposed to ionizing radiation are important and complex issues. Assessment may be optimized by evaluating individual adaptation and radiosensitivity, but it is not possible for a single model to account for all relevant parameters. Our goal was to develop approaches for the calculation of doses for persons chronically exposed to ionizing radiation, taking their radiosensitivities into consideration. On the basis of ex vivo radiation of blood samples, dose-effect models were constructed for dose ranges 0.01-2.0 and 0.01-0.4 Gy, using different cytogenetic criteria. The frequencies of "dicentric chromosomes and rings" at low doses are too low to have predictive value. The different responses of subjects to radiation made it possible to categorize them according to their radiosensitivities and to generate separate dose-effect curves for radiosensitive, average, and radioresistant individuals, reducing the amount of error in retrospective dosimetry.
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Affiliation(s)
- Oksana Cherednichenko
- Laboratory of Genetic Monitoring, Institute of Genetics and Physiology, Almaty 050060, Kazakhstan.
| | - Anastassiya Pilyugina
- Laboratory of Genetic Monitoring, Institute of Genetics and Physiology, Almaty 050060, Kazakhstan
| | - Serikbai Nuraliev
- Laboratory of Genetic Monitoring, Institute of Genetics and Physiology, Almaty 050060, Kazakhstan
| | - Dinara Azizbekova
- Laboratory of Genetic Monitoring, Institute of Genetics and Physiology, Almaty 050060, Kazakhstan
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Le Reun E, Granzotto A, Pêtre A, Bodgi L, Beldjoudi G, Lacornerie T, Vallet V, Bouchet A, Al-Choboq J, Bourguignon M, Thariat J, Bourhis J, Lartigau E, Foray N. Influence of the Hypersensitivity to Low Dose Phenomenon on the Tumor Response to Hypofractionated Stereotactic Body Radiation Therapy. Cancers (Basel) 2023; 15:3979. [PMID: 37568795 PMCID: PMC10416967 DOI: 10.3390/cancers15153979] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/30/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
Stereotactic body radiation therapy (SBRT) has made the hypofractionation of high doses delivered in a few sessions more acceptable. While the benefits of hypofractionated SBRT have been attributed to additional vascular, immune effects, or specific cell deaths, a radiobiological and mechanistic model is still needed. By considering each session of SBRT, the dose is divided into hundreds of minibeams delivering some fractions of Gy. In such a dose range, the hypersensitivity to low dose (HRS) phenomenon can occur. HRS produces a biological effect equivalent to that produced by a dose 5-to-10 times higher. To examine whether HRS could contribute to enhancing radiation effects under SBRT conditions, we exposed tumor cells of different HRS statuses to SBRT. Four human HRS-positive and two HRS-negative tumor cell lines were exposed to different dose delivery modes: a single dose of 0.2 Gy, 2 Gy, 10 × 0.2 Gy, and a single dose of 2 Gy using a non-coplanar isocentric minibeams irradiation mode were delivered. Anti-γH2AX immunofluorescence, assessing DNA double-strand breaks (DSB), was applied. In the HRS-positive cells, the DSB produced by 10 × 0.2 Gy and 2 Gy, delivered by tens of minibeams, appeared to be more severe, and they provided more highly damaged cells than in the HRS-negative cells, suggesting that more severe DSB are induced in the "SBRT modes" conditions when HRS occurs in tumor. Each SBRT session can be viewed as hyperfractionated dose delivery by means of hundreds of low dose minibeams. Under current SBRT conditions (i.e., low dose per minibeam and not using ultra-high dose-rate), the response of HRS-positive tumors to SBRT may be enhanced significantly. Interestingly, similar conclusions were reached with HRS-positive and HRS-negative untransformed fibroblast cell lines, suggesting that the HRS phenomenon may also impact the risk of post-RT tissue overreactions.
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Affiliation(s)
- Eymeric Le Reun
- U1296 Unit, “Radiation: Defense, Health and Environment”, Centre Léon-Bérard, Inserm, 28 Rue Laennec, 69008 Lyon, France; (E.L.R.); (A.G.); (A.P.); (A.B.); (J.A.-C.); (M.B.)
- Service de Radio-Oncologie, Centre Hospitalier Universitaire Vaudois (CHUV), 46 Rue du Bugnon, 1011 Lausanne, Switzerland; (V.V.); (J.B.)
| | - Adeline Granzotto
- U1296 Unit, “Radiation: Defense, Health and Environment”, Centre Léon-Bérard, Inserm, 28 Rue Laennec, 69008 Lyon, France; (E.L.R.); (A.G.); (A.P.); (A.B.); (J.A.-C.); (M.B.)
| | - Adeline Pêtre
- U1296 Unit, “Radiation: Defense, Health and Environment”, Centre Léon-Bérard, Inserm, 28 Rue Laennec, 69008 Lyon, France; (E.L.R.); (A.G.); (A.P.); (A.B.); (J.A.-C.); (M.B.)
- Département de Radiothérapie, Centre Léon-Bérard, 28 Rue Laennec, 69008 Lyon, France;
| | - Larry Bodgi
- Department of Radiation Oncology, American University of Beirut Medical Center, Riad El-Solh, Beirut 1107-2020, Lebanon;
| | - Guillaume Beldjoudi
- Département de Radiothérapie, Centre Léon-Bérard, 28 Rue Laennec, 69008 Lyon, France;
| | - Thomas Lacornerie
- Département de Radiothérapie, Centre Oscar-Lambret, 3 Rue Frédéric Combemale, 59000 Lille, France; (T.L.); (E.L.)
| | - Véronique Vallet
- Service de Radio-Oncologie, Centre Hospitalier Universitaire Vaudois (CHUV), 46 Rue du Bugnon, 1011 Lausanne, Switzerland; (V.V.); (J.B.)
| | - Audrey Bouchet
- U1296 Unit, “Radiation: Defense, Health and Environment”, Centre Léon-Bérard, Inserm, 28 Rue Laennec, 69008 Lyon, France; (E.L.R.); (A.G.); (A.P.); (A.B.); (J.A.-C.); (M.B.)
| | - Joëlle Al-Choboq
- U1296 Unit, “Radiation: Defense, Health and Environment”, Centre Léon-Bérard, Inserm, 28 Rue Laennec, 69008 Lyon, France; (E.L.R.); (A.G.); (A.P.); (A.B.); (J.A.-C.); (M.B.)
| | - Michel Bourguignon
- U1296 Unit, “Radiation: Defense, Health and Environment”, Centre Léon-Bérard, Inserm, 28 Rue Laennec, 69008 Lyon, France; (E.L.R.); (A.G.); (A.P.); (A.B.); (J.A.-C.); (M.B.)
- Département de Biophysique et Médecine Nucléaire, Université Paris Saclay, Versailles St. Quentin en Yvelines, 78035 Versailles, France
| | - Juliette Thariat
- Département de Radiothérapie, Centre François-Baclesse, 3 Avenue du Général Harris, 14076 Caen, France;
| | - Jean Bourhis
- Service de Radio-Oncologie, Centre Hospitalier Universitaire Vaudois (CHUV), 46 Rue du Bugnon, 1011 Lausanne, Switzerland; (V.V.); (J.B.)
| | - Eric Lartigau
- Département de Radiothérapie, Centre Oscar-Lambret, 3 Rue Frédéric Combemale, 59000 Lille, France; (T.L.); (E.L.)
| | - Nicolas Foray
- U1296 Unit, “Radiation: Defense, Health and Environment”, Centre Léon-Bérard, Inserm, 28 Rue Laennec, 69008 Lyon, France; (E.L.R.); (A.G.); (A.P.); (A.B.); (J.A.-C.); (M.B.)
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Polgár S, Schofield PN, Madas BG. Datasets of in vitro clonogenic assays showing low dose hyper-radiosensitivity and induced radioresistance. Sci Data 2022; 9:555. [PMID: 36075916 PMCID: PMC9458642 DOI: 10.1038/s41597-022-01653-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 08/19/2022] [Indexed: 11/19/2022] Open
Abstract
Low dose hyper-radiosensitivity and induced radioresistance are primarily observed in surviving fractions of cell populations exposed to ionizing radiation, plotted as the function of absorbed dose. Several biophysical models have been developed to quantitatively describe these phenomena. However, there is a lack of raw, openly available experimental data to support the development and validation of quantitative models. The aim of this study was to set up a database of experimental data from the public literature. Using Google Scholar search, 46 publications with 101 datasets on the dose-dependence of surviving fractions, with clear evidence of low dose hyper-radiosensitivity, were identified. Surviving fractions, their uncertainties, and the corresponding absorbed doses were digitized from graphs of the publications. The characteristics of the cell line and the irradiation were also recorded, along with the parameters of the linear-quadratic model and/or the induced repair model if they were provided. The database is available in STOREDB, and can be used for meta-analysis, for comparison with new experiments, and for development and validation of biophysical models. Measurement(s) | surviving fraction of cells | Technology Type(s) | optical microscopy | Factor Type(s) | absorbed dose | Sample Characteristic - Organism | Homo sapiens • Chinese hamster • Rattus sp. | Sample Characteristic - Environment | cell culture |
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Affiliation(s)
- Szabolcs Polgár
- Doctoral School of Physics, ELTE Eötvös Loránd University, Budapest, Hungary.,Environmental Physics Department, Centre for Energy Research, Budapest, Hungary
| | - Paul N Schofield
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Balázs G Madas
- Environmental Physics Department, Centre for Energy Research, Budapest, Hungary. .,Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Budapest, Hungary.
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Frosina G. Improving control of high‐grade glioma by ultra‐hyper‐fractionated radiotherapy. J Neurosci Res 2022; 100:933-946. [DOI: 10.1002/jnr.25030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/05/2021] [Accepted: 12/13/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Guido Frosina
- Mutagenesis & Cancer Prevention Unit IRCCS Ospedale Policlinico San Martino Genova Italy
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5
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Ma CMC. Pulsed low dose-rate radiotherapy: radiobiology and dosimetry. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac4c2f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 01/17/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Pulsed low dose-rate radiotherapy (PLDR) relies on two radiobiological findings, the hyper-radiosensitivity of tumor cells at small doses and the reduced normal tissue toxicity at low dose rates. This is achieved by delivering the daily radiation dose of 2 Gy in 10 sub-fractions (pulses) with a 3 min time interval, resulting in an effective low dose rate of 0.067 Gy min−1. In vitro cell studies and in vivo animal experiments demonstrated the therapeutic potential of PLDR treatments and provided useful preclinical data. Various treatment optimization strategies and delivery techniques have been developed for PLDR on existing linear accelerators. Preliminary results from early clinical studies have shown favorable outcomes for various treatment sites especially for recurrent cancers. This paper reviews the experimental findings of PLDR and dosimetric requirements for PLDR treatment planning and delivery, and summarizes major clinical studies on PLDR cancer treatments.
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Mohammadzadeh M, Alizadeh Z, Khodabakhsh R, Pazhang Y, Mohammadi S. Monte Carlo simulation for assessing absorbed dose effects of low-dose β-radiation ( 90Sr/ 90Y) on cytotoxicity and apoptotic death in K562 cells. J Cancer Res Ther 2022; 18:200-208. [DOI: 10.4103/jcrt.jcrt_909_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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The Effect of High-Dose-Rate Pulsed Radiation on the Survival of Clinically Relevant Radioresistant Cells. Life (Basel) 2021; 11:life11121295. [PMID: 34947826 PMCID: PMC8708735 DOI: 10.3390/life11121295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/20/2021] [Accepted: 11/22/2021] [Indexed: 12/20/2022] Open
Abstract
We demonstrated that low dose pulsed radiation (0.25 Gy) at a high-dose-rate, even for very short intervals (10 s), decreases cell survival to a greater extent than single exposure to a similar total dose and dose rate. The objective of this study was to clarify whether high-dose-rate pulsed radiation is effective against SAS-R, a clinically relevant radioresistant cell line. Cell survival following high-dose-rate pulsed radiation was evaluated via a colony assay. Flow cytometry was utilized to evaluate γH2AX, a molecular marker of DNA double-strand breaks and delayed reactive oxygen species (ROS) associated with radiation-induced apoptosis. Increased cytotoxicity was observed in SAS-R and parent SAS cells in response to high dose rate pulsed radiation compared to single dose, as determined by colony assays. Residual γH2AX in both cells subjected to high-dose-rate pulsed radiation showed a tendency to increase, with a significant increase observed in SAS cells at 72 h. In addition, high-dose-rate pulsed radiation increased delayed ROS more than the single exposure did. These results indicate that high-dose-rate pulsed radiation was associated with residual γH2AX and delayed ROS, and high-dose-rate pulsed radiation may be used as an effective radiotherapy procedure against radioresistant cells.
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Wang Q, Chen Y, Chang H, Hu T, Wang J, Xie Y, Cheng J. The Role and Mechanism of ATM-Mediated Autophagy in the Transition From Hyper-Radiosensitivity to Induced Radioresistance in Lung Cancer Under Low-Dose Radiation. Front Cell Dev Biol 2021; 9:650819. [PMID: 34055781 PMCID: PMC8149741 DOI: 10.3389/fcell.2021.650819] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/07/2021] [Indexed: 11/15/2022] Open
Abstract
Objective: This study aimed to investigate the effect of ataxia telangiectasia mutated (ATM)–mediated autophagy on the radiosensitivity of lung cancer cells under low-dose radiation and to further investigate the role of ATM and its specific mechanism in the transition from hyper-radiosensitivity (HRS) to induced radioresistance (IRR). Methods: The changes in the HRS/IRR phenomenon in A549 and H460 cells were verified by colony formation assay. Changes to ATM phosphorylation and cell autophagy in A549 and H460 cells under different low doses of radiation were examined by western blot, polymerase chain reaction (PCR), and electron microscopy. ATM expression was knocked down by short interfering RNA (siRNA) transfection, and ATM-regulated molecules related to autophagy pathways were screened by transcriptome sequencing analysis. The detection results were verified by PCR and western blot. The differential metabolites were screened by transcriptome sequencing and verified by colony formation assay and western blot. The nude mouse xenograft model was used to verify the results of the cell experiments. Results: (1) A549 cells with high expression of ATM showed positive HRS/IRR, whereas H460 cells with low expression of ATM showed negative HRS/IRR. After the expression of ATM decreased, the HRS phenomenon in A549 cells increased, and the radiosensitivity of H460 cells also increased. This phenomenon was associated with the increase in the autophagy-related molecules phosphorylated c-Jun N-terminal kinase (p-JNK) and autophagy/Beclin 1 regulator 1 (AMBRA1). (2) DL-Norvaline, a product of carbon metabolism in cells, inhibited autophagy in A549 cells under low-dose radiation. DL-Norvaline increased the expression levels of ATM, JNK, and AMBRA1 in A549 cells. (3) Mouse experiments confirmed the regulatory role of ATM in autophagy and metabolism and its function in HRS/IRR. Conclusion: ATM may influence autophagy through p-JNK and AMBRA1 to participate in the regulation of the HRS/IRR phenomenon. Autophagy interacts with the cellular carbon metabolite DL-Norvaline to participate in regulating the low-dose radiosensitivity of cells.
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Affiliation(s)
- Qiong Wang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yangyang Chen
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haiyan Chang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ting Hu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jue Wang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuxiu Xie
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Cheng
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Demirkıran G, Kalaycı Demir G, Güzeliş C. Coupling of cell fate selection model enhances DNA damage response and may underlie BE phenomenon. IET Syst Biol 2020; 14:96-106. [PMID: 32196468 PMCID: PMC8687165 DOI: 10.1049/iet-syb.2019.0081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/24/2019] [Accepted: 10/31/2019] [Indexed: 11/20/2022] Open
Abstract
Double-strand break-induced (DSB) cells send signal that induces DSBs in neighbour cells, resulting in the interaction among cells sharing the same medium. Since p53 network gives oscillatory response to DSBs, such interaction among cells could be modelled as an excitatory coupling of p53 network oscillators. This study proposes a plausible coupling model of three-mode two-dimensional oscillators, which models the p53-mediated cell fate selection in globally coupled DSB-induced cells. The coupled model consists of ATM and Wip1 proteins as variables. The coupling mechanism is realised through ATM variable via a mean-field modelling the bystander signal in the intercellular medium. Investigation of the model reveals that the coupling generates more sensitive DNA damage response by affecting cell fate selection. Additionally, the authors search for the cause-effect relationship between coupled p53 network oscillators and bystander effect (BE) endpoints. For this, they search for the possible values of uncertain parameters that may replicate BE experiments' results. At certain parametric regions, there is a correlation between the outcomes of cell fate and endpoints of BE, suggesting that the intercellular coupling of p53 network may manifest itself as the form of observed BEs.
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Affiliation(s)
- Gökhan Demirkıran
- Electrical and Electronics Engineering, Yaşar University, Selçuk Yaşar Kampüsü, İzmir, Turkey.
| | - Güleser Kalaycı Demir
- Electrical and Electronics Engineering, Dokuz Eylül University, Tınaztepe, İzmir, Turkey
| | - Cüneyt Güzeliş
- Electrical and Electronics Engineering, Yaşar University, Selçuk Yaşar Kampüsü, İzmir, Turkey
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Pulsed low dose-rate irradiation response in isogenic HNSCC cell lines with different radiosensitivity. Radiol Oncol 2020; 54:168-179. [PMID: 32229678 PMCID: PMC7276640 DOI: 10.2478/raon-2020-0015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 03/01/2020] [Indexed: 12/16/2022] Open
Abstract
Background Management of locoregionally recurrent head and neck squamous cell carcinomas (HNSCC) is challenging due to potential radioresistance. Pulsed low-dose rate (PLDR) irradiation exploits phenomena of increased radiosensitivity, low-dose hyperradiosensitivity (LDHRS), and inverse dose-rate effect. The purpose of this study was to evaluate LDHRS and the effect of PLDR irradiation in isogenic HNSCC cells with different radiosensitivity. Materials and methods Cell survival after different irradiation regimens in isogenic parental FaDu and radioresistant FaDu-RR cells was determined by clonogenic assay; post irradiation cell cycle distribution was studied by flow cytometry; the expression of DNA damage signalling genes was assesed by reverse transcription-quantitative PCR. Results Radioresistant Fadu-RR cells displayed LDHRS and were more sensitive to PLDR irradiation than parental FaDu cells. In both cell lines, cell cycle was arrested in G2/M phase 5 hours after irradiation. It was restored 24 hours after irradiation in parental, but not in the radioresistant cells, which were arrested in G1-phase. DNA damage signalling genes were under-expressed in radioresistant compared to parental cells. Irradiation increased DNA damage signalling gene expression in radioresistant cells, while in parental cells only few genes were under-expressed. Conclusions We demonstrated LDHRS in isogenic radioresistant cells, but not in the parental cells. Survival of LDHRS-positive radioresistant cells after PLDR was significantly reduced. This reduction in cell survival is associated with variations in DNA damage signalling gene expression observed in response to PLDR most likely through different regulation of cell cycle checkpoints.
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Differential miRNA expression profiling reveals miR-205-3p to be a potential radiosensitizer for low- dose ionizing radiation in DLD-1 cells. Oncotarget 2018; 9:26387-26405. [PMID: 29899866 PMCID: PMC5995186 DOI: 10.18632/oncotarget.25405] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 04/28/2018] [Indexed: 12/12/2022] Open
Abstract
Enhanced radiosensitivity at low doses of ionizing radiation (IR) (0.2 to 0.6 Gy) has been reported in several cell lines. This phenomenon, known as low doses hyper-radiosensitivity (LDHRS), appears as an opportunity to decrease toxicity of radiotherapy and to enhance the effects of chemotherapy. However, the effect of low single doses IR on cell death is subtle and the mechanism underlying LDHRS has not been clearly explained, limiting the utility of LDHRS for clinical applications. To understand the mechanisms responsible for cell death induced by low-dose IR, LDHRS was evaluated in DLD-1 human colorectal cancer cells and the expression of 80 microRNAs (miRNAs) was assessed by qPCR array. Our results show that DLD-1 cells display an early DNA damage response and apoptotic cell death when exposed to 0.6 Gy. miRNA expression profiling identified 3 over-expressed (miR-205-3p, miR-1 and miR-133b) and 2 down-regulated miRNAs (miR-122-5p, and miR-134-5p) upon exposure to 0.6 Gy. This miRNA profile differed from the one in cells exposed to high-dose IR (12 Gy), supporting a distinct low-dose radiation-induced cell death mechanism. Expression of a mimetic miR-205-3p, the most overexpressed miRNA in cells exposed to 0.6 Gy, induced apoptotic cell death and, more importantly, increased LDHRS in DLD-1 cells. Thus, we propose miR-205-3p as a potential radiosensitizer to low-dose IR.
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Olobatuyi O, de Vries G, Hillen T. Effects of G2-checkpoint dynamics on low-dose hyper-radiosensitivity. J Math Biol 2018; 77:1969-1997. [PMID: 29679122 DOI: 10.1007/s00285-018-1236-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 02/17/2018] [Indexed: 02/03/2023]
Abstract
In experimental studies, it has been found that certain cell lines are more sensitive to low-dose radiation than would be expected from the classical Linear-Quadratic model (LQ model). In fact, it is frequently observed that cells incur more damage at low dose (say 0.3 Gy) than at higher dose (say 1 Gy). This effect has been termed hyper-radiosensitivity (HRS). The effect depends on the type of cells and on their phase in the cell cycle when radiation is applied. Experiments have shown that the G2-checkpoint plays an important role in the HRS effects. Here we design and analyze a differential equation model for the cell cycle that includes G2-checkpoint dynamics and radiation treatment. We fit the model to surviving fraction data for different cell lines including glioma cells, prostate cancer cells, as well as to cell populations that are enriched in certain phases of the cell cycle. The HRS effect is measured in the literature through [Formula: see text], the ratio of slope [Formula: see text] of the surviving fraction curve at zero dose to slope [Formula: see text] of the corresponding LQ model. We derive an explicit formula for this ratio and we show that it corresponds very closely to experimental observations. Finally, we identify the dependence of this ratio on the surviving fraction at 2 Gy. It was speculated in the literature that such dependence exists. Our theoretical analysis will help to more systematically identify the HRS in cell lines, and opens doors to analyze its use in cancer treatment.
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Affiliation(s)
- Oluwole Olobatuyi
- Collaborative Mathematical Biology Group (formerly Center for Mathematical Biology), Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, T6G 2G1, Canada.
| | - Gerda de Vries
- Collaborative Mathematical Biology Group (formerly Center for Mathematical Biology), Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, T6G 2G1, Canada
| | - Thomas Hillen
- Collaborative Mathematical Biology Group (formerly Center for Mathematical Biology), Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, T6G 2G1, Canada
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Wu SY, Wu ATH, Liu SH. MicroRNA-17-5p regulated apoptosis-related protein expression and radiosensitivity in oral squamous cell carcinoma caused by betel nut chewing. Oncotarget 2018; 7:51482-51493. [PMID: 27285985 PMCID: PMC5239490 DOI: 10.18632/oncotarget.9856] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 05/26/2016] [Indexed: 01/07/2023] Open
Abstract
Betel nut chewing is associated with oral cavity cancer. Radiotherapy is one of the therapeutic approaches. Here, we used miR-17-5p antisense oligonucleotides (AS-ODNs) and human apoptosis protein array to clarify which apoptosis-related proteins are increased or decreased by miR-17-5p in betel nut chewing- oral squamous cell carcinoma OC3 cells. Furthermore, miR-17-5p AS-ODN was used to evaluate the radio-sensitization effects both in vitro and in vivo. An OC3 xenograft tumor model in severe combined immunodeficiency mice was used to determine the effect of miR-17-5p AS ODN on tumor irradiation. We simultaneously detected the relative expressions of 35 apoptosis-related proteins in irradiated OC3 cells that were treated with miR-17-5p AS-ODN or a control ODN. Several proteins, including p21, p53, TNF RI, FADD, cIAP-1, HIF-1α, and TRAIL R1, were found to be up- or downregulated by miR-17-5p in OC3 cells; their expression patterns were also confirmed by Western blotting. We further clarified the role of p53 in irradiated OC3 cells, using a p53 overexpression strategy. The results revealed that the enhancement of p53 expression significantly enhanced radiation-induced G2/M arrest of the OC3 cells. In the in vivo study, treatment of miR-17-5p AS-ODN before irradiation significantly enhanced p53 expression and reduced tumor growth. These results suggest that miR-17-5p increases or decreases apoptosis-related proteins in irradiated OC3 cells; its effect on p53 protein expression contributes to the modulation of the radiosensitivity of the OC3 cells.
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Affiliation(s)
- Szu-Yuan Wu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Radiation Oncology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.,Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Biotechnology, Hungkuang University, Taichung, Taiwan
| | - Alexander T H Wu
- The Ph.D. Program for Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Shing-Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Pediatrics, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
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Terashima S, Hosokawa Y, Tsuruga E, Mariya Y, Nakamura T. Impact of time interval and dose rate on cell survival following low-dose fractionated exposures. JOURNAL OF RADIATION RESEARCH 2017; 58:782-790. [PMID: 28595296 PMCID: PMC5710595 DOI: 10.1093/jrr/rrx025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/08/2017] [Indexed: 05/23/2023]
Abstract
Enhanced cell lethality, also known as hyper-radiosensitivity, has been reported at low doses of radiation (≤0.5 Gy) in various cell lines, and is expected to be an effective cancer therapy. We conducted this study to examine the impact of time interval and dose rate of low-dose fractionated exposures with a short time interval. We evaluated the cell-survival rates of V79 and A549 cells using clonogenic assays. We performed fractionated exposures in unit doses of 0.25, 0.5, 1.0 and 2.0 Gy. We exposed the cells to 2 Gy of X-rays (i) at dose-rates of 1.0, 1.5 and 2.0 Gy/min at 1-min intervals and (ii) at a dose-rate of 2.0 Gy/min at 10-s, 1-min and 3-min intervals by fractionated exposures. Apoptosis and cell cycle analyses were also evaluated in the fractionated exposures (unit dose 0.25 Gy) and compared with single exposures by using flow cytometry. Both cell-type survival rates with fractionated exposures (unit dose 0.25 Gy) with short time intervals were markedly lower than those for single exposures delivering the same dose. When the dose rates were lower, the cytotoxic effect decreased compared with exposure to a dose-rate of 2.0 Gy/min. On the other hand, levels of apoptosis and cell cycle distribution were not significantly different between low-dose fractionated exposures and single exposures in either cell line. These results indicate that a stronger cytotoxic effect was induced with low-dose fractionated exposures with a short time interval for a given dose due to the hyper-radiosensitivity phenomenon, suggesting that dose rates are important for effective low-dose fractionated exposures.
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Affiliation(s)
- Shingo Terashima
- Department of Radiation Science, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Yoichiro Hosokawa
- Department of Radiation Science, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Eichi Tsuruga
- Department of Radiation Science, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
| | - Yasushi Mariya
- Department of Radiology, Mutsu General Hospital, 1-2-8 Kogawa-cho, Mutsu, Aomori 035-8601, Japan
| | - Toshiya Nakamura
- Department of Bioscience and Laboratory Medicine, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
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15
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Piotrowski I, Kulcenty K, Suchorska WM, Skrobała A, Skórska M, Kruszyna-Mochalska M, Kowalik A, Jackowiak W, Malicki J. Carcinogenesis Induced by Low-dose Radiation. Radiol Oncol 2017; 51:369-377. [PMID: 29333114 PMCID: PMC5765312 DOI: 10.1515/raon-2017-0044] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 09/25/2017] [Indexed: 01/10/2023] Open
Abstract
Background Although the effects of high dose radiation on human cells and tissues are relatively well defined, there is no consensus regarding the effects of low and very low radiation doses on the organism. Ionizing radiation has been shown to induce gene mutations and chromosome aberrations which are known to be involved in the process of carcinogenesis. The induction of secondary cancers is a challenging long-term side effect in oncologic patients treated with radiation. Medical sources of radiation like intensity modulated radiotherapy used in cancer treatment and computed tomography used in diagnostics, deliver very low doses of radiation to large volumes of healthy tissue, which might contribute to increased cancer rates in long surviving patients and in the general population. Research shows that because of the phenomena characteristic for low dose radiation the risk of cancer induction from exposure of healthy tissues to low dose radiation can be greater than the risk calculated from linear no-threshold model. Epidemiological data collected from radiation workers and atomic bomb survivors confirms that exposure to low dose radiation can contribute to increased cancer risk and also that the risk might correlate with the age at exposure. Conclusions Understanding the molecular mechanisms of response to low dose radiation is crucial for the proper evaluation of risks and benefits that stem from these exposures and should be considered in the radiotherapy treatment planning and in determining the allowed occupational exposures.
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Affiliation(s)
- Igor Piotrowski
- Radiobiology Laboratory, Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15 Street, Poznań, Poland
| | - Katarzyna Kulcenty
- Radiobiology Laboratory, Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15 Street, Poznań, Poland.,Department of Electroradiology, University of Medical Sciences, Poznań, Poland
| | - Wiktoria Maria Suchorska
- Radiobiology Laboratory, Department of Medical Physics, Greater Poland Cancer Centre, Garbary 15 Street, Poznań, Poland.,Department of Electroradiology, University of Medical Sciences, Poznań, Poland
| | - Agnieszka Skrobała
- Department of Electroradiology, University of Medical Sciences, Poznań, Poland.,Department of Medical Physics, Greater Poland Cancer Centre, Poznań, Poland
| | - Małgorzata Skórska
- Department of Medical Physics, Greater Poland Cancer Centre, Poznań, Poland
| | - Marta Kruszyna-Mochalska
- Department of Electroradiology, University of Medical Sciences, Poznań, Poland.,Department of Medical Physics, Greater Poland Cancer Centre, Poznań, Poland
| | - Anna Kowalik
- Department of Medical Physics, Greater Poland Cancer Centre, Poznań, Poland
| | | | - Julian Malicki
- Department of Electroradiology, University of Medical Sciences, Poznań, Poland.,Department of Medical Physics, Greater Poland Cancer Centre, Poznań, Poland
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16
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Yang G, Li W, Jiang H, Liang X, Zhao Y, Yu D, Zhou L, Wang G, Tian H, Han F, Cai L, Cui J. Low-dose radiation may be a novel approach to enhance the effectiveness of cancer therapeutics. Int J Cancer 2016; 139:2157-68. [PMID: 27299986 DOI: 10.1002/ijc.30235] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 05/01/2016] [Accepted: 06/06/2016] [Indexed: 12/26/2022]
Abstract
It has been generally accepted that both natural and man-made sources of ionizing radiation contribute to human exposure and consequently pose a possible risk to human health. However, accumulating evidence has shown that the biological effects of low-dose radiation (LDR) are different from those of high-dose radiation. LDR can stimulate proliferation of normal cells and activate their defense systems, while these biological effects are not observed in some cancer cell types. Although there is still no concordance on this matter, the fact that LDR has the potential to enhance the effects of cancer therapeutics and reduce the toxic side effects of anti-cancer therapy has garnered significant interest. Here, we provide an overview of the current knowledge regarding the experimental data detailing the different responses of normal and cancer tissues to LDR, the underlying mechanisms, and its significance in clinical application.
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Affiliation(s)
- Guozi Yang
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China.,Department of Radiation-Oncology, The First Hospital of Jilin University, Changchun, 130021, China
| | - Wei Li
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Hongyu Jiang
- Health Examination Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Xinyue Liang
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Yuguang Zhao
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Dehai Yu
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Lei Zhou
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Guanjun Wang
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Huimin Tian
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Fujun Han
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China
| | - Lu Cai
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China. .,Kosair Children's Hospital Research Institute, Departments of Pediatrics, Radiation Oncology, Pharmacology and Toxicology of the University of Louisville, Louisville, KY, 40202.
| | - Jiuwei Cui
- Cancer Center, The First Hospital of Jilin University, Changchun, 130021, China.
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17
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A Systematic Comparison Identifies an ATP-Based Viability Assay as Most Suitable Read-Out for Drug Screening in Glioma Stem-Like Cells. Stem Cells Int 2016; 2016:5623235. [PMID: 27274737 PMCID: PMC4871979 DOI: 10.1155/2016/5623235] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 02/15/2016] [Accepted: 02/17/2016] [Indexed: 11/18/2022] Open
Abstract
Serum-free culture methods for patient-derived primary glioma cultures, selecting for glioma stem-like cells (GSCs), are becoming the gold standard in neurooncology research. These GSCs can be implemented in drug screens to detect patient-specific responses, potentially bridging the translational gap to personalized medicine. Since numerous compounds are available, a rapid and reliable readout for drug efficacies is required. This can be done using approaches that measure viability, confluency, cytotoxicity, or apoptosis. To determine which assay is best suitable for drug screening, 10 different assays were systematically tested on established glioma cell lines and validated on a panel of GSCs. General applicability was assessed using distinct treatment modalities, being temozolomide, radiation, rapamycin, and the oncolytic adenovirus Delta24-RGD. The apoptosis and cytotoxicity assays did not unequivocally detect responses and were excluded from further testing. The NADH- and ATP-based viability assays revealed comparable readout for all treatments; however, the latter had smaller standard deviations and direct readout. Importantly, drugs that interfere with cell metabolism require alternative techniques such as confluency monitoring to accurately measure treatment effects. Taken together, our data suggest that the combination of ATP luminescence assays with confluency monitoring provides the most specific and reproducible readout for drug screening on primary GSCs.
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18
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Moghaddasi L, Bezak E, Harriss-Phillips W. Monte-Carlo model development for evaluation of current clinical target volume definition for heterogeneous and hypoxic glioblastoma. Phys Med Biol 2016; 61:3407-26. [PMID: 27046324 DOI: 10.1088/0031-9155/61/9/3407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Clinical target volume (CTV) determination may be complex and subjective. In this work a microscopic-scale tumour model was developed to evaluate current CTV practices in glioblastoma multiforme (GBM) external radiotherapy. Previously, a Geant4 cell-based dosimetry model was developed to calculate the dose deposited in individual GBM cells. Microscopic extension probability (MEP) models were then developed using Matlab-2012a. The results of the cell-based dosimetry model and MEP models were combined to calculate survival fractions (SF) for CTV margins of 2.0 and 2.5 cm. In the current work, oxygenation and heterogeneous radiosensitivity profiles were incorporated into the GBM model. The genetic heterogeneity was modelled using a range of α/β values (linear-quadratic model parameters) associated with different GBM cell lines. These values were distributed among the cells randomly, taken from a Gaussian-weighted sample of α/β values. Cellular oxygen pressure was distributed randomly taken from a sample weighted to profiles obtained from literature. Three types of GBM models were analysed: homogeneous-normoxic, heterogeneous-normoxic, and heterogeneous-hypoxic. The SF in different regions of the tumour model and the effect of the CTV margin extension from 2.0-2.5 cm on SFs were investigated for three MEP models. The SF within the beam was increased by up to three and two orders of magnitude following incorporation of heterogeneous radiosensitivities and hypoxia, respectively, in the GBM model. However, the total SF was shown to be overdominated by the presence of tumour cells in the penumbra region and to a lesser extent by genetic heterogeneity and hypoxia. CTV extension by 0.5 cm reduced the SF by a maximum of 78.6 ± 3.3%, 78.5 ± 3.3%, and 77.7 ± 3.1% for homogeneous and heterogeneous-normoxic, and heterogeneous hypoxic GBMs, respectively. Monte-Carlo model was developed to quantitatively evaluate SF for genetically heterogeneous and hypoxic GBM with two CTV margins and three MEP distributions. The results suggest that photon therapy may not provide cure for hypoxic and genetically heterogeneous GBM. However, the extension of the CTV margin by 0.5 cm could be beneficial to delay the recurrence time for this tumour type due to significant increase in tumour cell irradiation.
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Affiliation(s)
- L Moghaddasi
- Department of Medical Physics, Royal Adelaide Hospital, Adelaide, SA, Australia. School of Chemistry & Physics, University of Adelaide, Adelaide, SA, Australia
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19
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Fernandez-Palomo C, Seymour C, Mothersill C. Inter-Relationship between Low-Dose Hyper-Radiosensitivity and Radiation-Induced Bystander Effects in the Human T98G Glioma and the Epithelial HaCaT Cell Line. Radiat Res 2016; 185:124-33. [PMID: 26849405 DOI: 10.1667/rr14208.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Over the past several years, investigations in both low-dose hyper-radiosensitivity and increased radioresistance have been a focus of radiation oncology and biology research, since both conditions occur primarily in tumor cell lines. There has been significant progress in elucidating their signaling pathways, however uncertainties exist when they are studied together with radiation-induced bystander effects. Therefore, the aim of this work was to further investigate this relationship using the T98G glioma and HaCaT cell lines. T98G glioma cells have demonstrated a strong transition from hyper-radiosensitivity to induced radioresistance, and HaCaT cells do not show low-dose hypersensitivity. Both cell lines were paired using a mix-and-match protocol, which involved growing nonirradiated cells in culture media from irradiated cells and covering all possible combinations between them. The end points analyzed were clonogenic cell survival and live calcium measurements through the cellular membrane. Our data demonstrated that T98G cells produced bystander signals that decreased the survival of both reporter T98G and HaCaT cells. The bystander effect occurred only when T98G cells were exposed to doses below 1 Gy, which was corroborated by the induction of calcium fluxes. However, when bystander signals originated from HaCaT cells, the survival fraction increased in reporter T98G cells while it decreased in HaCaT cells. Moreover, the corresponding calcium data showed no calcium fluxes in T98G cells, while HaCaT cells displayed a biphasic calcium profile. In conclusion, our findings indicate a possible link between low-dose hyper-radiosensitivity and bystander effects. This relationship varies depending on which cell line functions as the source of bystander signals. This further suggests that the bystander mechanisms are more complex than previously expected and caution should be taken when extrapolating bystander results across all cell lines and all radiation doses.
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Affiliation(s)
- Cristian Fernandez-Palomo
- Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, L8S 1K4, Canada
| | - Colin Seymour
- Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, L8S 1K4, Canada
| | - Carmel Mothersill
- Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, L8S 1K4, Canada
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20
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Abstract
In almost all patients, malignant glioma recurs following initial treatment with maximal safe resection, conformal radiotherapy, and temozolomide. This review describes the many options for treatment of recurrent malignant gliomas, including reoperation, alternating electric field therapy, chemotherapy, stereotactic radiotherapy or radiosurgery, or some combination of these modalities, presenting the evidence for each approach. No standard of care has been established, though the antiangiogenic agent, bevacizumab; stereotactic radiotherapy or radiosurgery; and, perhaps, combined treatment with these 2 modalities appear to offer modest benefits over other approaches. Clearly, randomized trials of these options would be advantageous, and novel, more efficacious approaches are urgently needed.
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Affiliation(s)
- John P Kirkpatrick
- Department of Radiation Oncology, Duke Cancer Institute, Durham, NC; Department of Surgery, Duke Cancer Institute, Durham, NC.
| | - John H Sampson
- Department of Radiation Oncology, Duke Cancer Institute, Durham, NC; Department of Surgery, Duke Cancer Institute, Durham, NC
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21
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Joshi GS, Joiner MC, Tucker JD. Cytogenetic characterization of low-dose hyper-radiosensitivity in Cobalt-60 irradiated human lymphoblastoid cells. Mutat Res 2014; 770:69-78. [PMID: 25771872 DOI: 10.1016/j.mrfmmm.2014.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/06/2014] [Accepted: 09/16/2014] [Indexed: 06/04/2023]
Abstract
The dose-effect relationships of cells exposed to ionizing radiation are frequently described by linear quadratic (LQ) models over an extended dose range. However, many mammalian cell lines, when acutely irradiated in G2 at doses ≤0.3Gy, show hyper-radiosensitivity (HRS) as measured by reduced clonogenic cell survival, thereby indicating greater cell lethality than is predicted by extrapolation from high-dose responses. We therefore hypothesized that the cytogenetic response in G2 cells to low doses would also be steeper than predicted by LQ extrapolation from high doses. We tested our hypothesis by exposing four normal human lymphoblastoid cell lines to 0-400cGy of Cobalt-60 gamma radiation. The cytokinesis block micronucleus assay was used to determine the frequencies of micronuclei and nucleoplasmic bridges. To characterize the dependence of the cytogenetic damage on dose, univariate and multivariate regression analyses were used to compare the responses in the low- (HRS) and high-dose response regions. Our data indicate that the slope of the response for all four cell lines at ≤20cGy during G2 is greater than predicted by an LQ extrapolation from the high-dose responses for both micronuclei and bridges. These results suggest that the biological consequences of low-dose exposures could be underestimated and may not provide accurate risk assessments following such exposures.
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Affiliation(s)
- Gnanada S Joshi
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States
| | - Michael C Joiner
- Department of Radiation Oncology, Wayne State University, Detroit, MI 48201, United States
| | - James D Tucker
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, United States.
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22
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Wang R, Xiao X, Wang PY, Wang L, Guan Q, Du C, Wang XJ. Stimulation of autophagic activity in human glioma cells by anti-proliferative ardipusilloside I isolated from Ardisia pusilla. Life Sci 2014; 110:15-22. [PMID: 24984215 DOI: 10.1016/j.lfs.2014.06.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 05/10/2014] [Accepted: 06/20/2014] [Indexed: 01/21/2023]
Abstract
AIMS Ardipusilloside I (ADS-I), a triterpenoid saponin isolated from Ardisia pusilla A.DC (Myrsinaceae), has been recently tested for cancer treatment including brain cancer. However, the mechanism of its action remains elusive. The present study was to investigate the role of autophagy activation in the anti-tumor activities of ADS-I in human glioma cells. MAIN METHODS The tetrazolium dye (MTT) colorimetric assay was used for the measurement of cell proliferation in cultured glioma cells, transmission electron microscopy (TEM) for the examination of autophagic activity, flow cytometric analysis for the determination of cell cycle and apoptotic cells, and immunocytochemistry and Western blot for protein expression of microtubule-associated protein light-chain 3 (LC3) and Beclin 1. KEY FINDINGS ADS-I significantly inhibited the proliferation of both U373 and T98G glioma cells in cultures in a dose-dependent manner. The cytotoxic activity of ADS-I against glioma cell growth was associated not only with the induction of cell cycle arrest at G2/M phase and cell apoptosis in flow cytometric analysis, but also with the activation of autophagy, indicated by the formation of autophagosomes and up-regulated expression of both autophagic protein Beclin 1 and LC3 in glioma cells. Additionally, the treatment with chloroquine, an autophagy inhibitor, reduced ADS-1-mediated cell death. SIGNIFICANCE These data suggest that the anti-proliferative activity of ADS-I in human glioma cells is associated with the activation of autophagy in addition to cell cycle arrest and apoptosis, and the antagonistic effect of chloroquine suggests an important role of autophagy in ADS-I-mediated cell death against tumor growth.
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Affiliation(s)
- Rong Wang
- Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China; Department of Pharmacology, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710061, China
| | - Xin Xiao
- Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Peng-Yuan Wang
- Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Lin Wang
- Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Qiunong Guan
- Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
| | - Caigan Du
- Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada.
| | - Xiao-Juan Wang
- Department of Pharmacy, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
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