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Abstract
Intimal hyperplasia represents a serious complication limiting the long-term benefits of vascular interventions such as balloon angioplasty and stent placement. Although pharmacological interventions have attempted to curtail restenosis, they have not been shown to be effective to date. Radiotherapy is one alternative that has shown promise as an inhibitor of intimal hyperplasia in several animal models. Irradiation causes cell death by producing irreparable damage to DNA. This is believed to be the mechanism of inhibition of VSMC proliferation. Delivery of irradiation can be either intraluminal via an angiographically directed catheter or extraluminal using an external radiation source such as an x-ray device. Intraluminal irradiation has generally utilized either gamma or beta-emitting sources. Both have been effective in producing a dose response, although some studies advocate the use of beta-type irradiation as a safer, more efficient means of delivery. Extraluminal irradiation also has been an effective inhibitor of intimal hyperplasia. Studies suggest that this form of irradiation provides a more even-dose distribution to vessel walls than an intravascular delivery system. The use of radiotherapy has more recently been extended to clinical trials, and initial studies have shown promising results. The success of irradiation must be balanced with its potential complications including radiation-induced arteritis, coronary artery stenosis, and secondary development of malignancy. Although these have been associated with irradiation, the dose used in these cases was often considerably higher than those used in the treatment of intimal hyperplasia. Finally, with the advent of gene therapy, irradiation may provide an additional means of supplementing this new type of therapy through radiation-inducible gene therapy.
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Affiliation(s)
- J E Fortunato
- Department of Surgery, The University of Chicago, Illinois 60637, USA
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52
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Abstract
In vitro studies have shown that ionizing radiation can cause increases in some cytokine mRNA levels and activation of the nuclear NF-kappa B and/or AP1 transcription factors which have been implicated in the transcriptional regulation of many cytokine genes. Thus, radiation-induced upregulation of cytokine mRNAs appeared to be in part a direct consequence of transcription factor activation. To test this in vitro model in vivo, the effects of whole-body X-irradiation (0-10 Gy) on cytokine and other gene mRNA levels have been examined in mice. Increases and decreases in cytokine mRNA levels were detected in tissues which underwent an early wave of apoptosis (bone marrow and/or spleen), but not in more radioresistant tissues (kidney, liver, brain, and heart). Some mouse strain-specific differences were observed, but none of the changes in mRNA level was detected in p53-/- mice. As activation of the NF-kappa B and AP1 transcription factors was not detected in early-(spleen) or late-(liver) responding tissues in 10 Gy X-irradiated p53+/+ mice in vivo, it is concluded that the modulation of cytokine gene expression in vivo is p53-dependent and indirectly associated with apoptosis.
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Affiliation(s)
- N C Kerr
- MRC Radiation and Genome Stability Unit, Chilton, Didcot, Oxon, U.K
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53
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54
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Affiliation(s)
- N E Crompton
- Life Sciences Department, Paul Scherrer Institute, Villigen, Switzerland.
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55
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Stecca C, Gerber GB. Adaptive response to DNA-damaging agents: a review of potential mechanisms. Biochem Pharmacol 1998; 55:941-51. [PMID: 9605418 DOI: 10.1016/s0006-2952(97)00448-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The study of the adaptive response, i.e. a reduced effect from a higher challenging dose of a stressor when a smaller inducing dose had been applied a few hours earlier, has opened many new vistas into the mechanisms by which cells can adapt to hazardous environments. Although the entire chain from the initial event, supposedly the presence of DNA damage, to the end effect, presumably improved DNA repair, has not been fully elucidated, many individual links have been postulated. Initial elements--following the still unknown signal for the presence of radiation damage--are various kinases (protein kinase C and stress-activated protein kinases), which, in turn, induce early response genes whose products initiate a cascade of protein-DNA interactions that regulate gene transcription and ultimately result in specific biological responses. These responses include the activation of later genes that can promote production of growth factors and cytokines, trigger DNA repair, and regulate progress through the cell cycle. Indeed, there appears to be a relation between the induction of the adaptive response and the effects of radiation and cytostatic agents on the cell cycle, although these effects, especially the G1 delay, occur at much higher doses than the adaptive response, and one may not indiscriminately extrapolate mechanisms responsible for cell cycle changes observed at high doses, e.g. for radiation in the order of grays, to those involved in the adaptive responses at much lower doses, i.e. some tens of milligrays.
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Affiliation(s)
- C Stecca
- Teratogenicity and Mutagenicity Unit, Catholic University of Louvain, Brussels, Belgium.
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56
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Menichini P, Viaggi S, Gallerani E, Fronza G, Ottaggio L, Comes A, Ellwart JW, Abbondandolo A. A gene trap approach to isolate mammalian genes involved in the cellular response to genotoxic stress. Nucleic Acids Res 1997; 25:4803-7. [PMID: 9365260 PMCID: PMC147125 DOI: 10.1093/nar/25.23.4803] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Treatment of cells with DNA damaging agents leads to induction of a variety of genes involved in different cellular processes. We have applied a lacZ-based gene trap strategy to search for new mammalian genes induced by genotoxic stress. A population of 32 x 10(3) neo r clones stably transfected with a gene trap vector was obtained, stained with fluorescein di-beta-d-galactopyranoside and analyzed by flow activated cell sorting and replica plating. This strategy allowed isolation of 30 neo r 'putative inducible' cell lines expressing lacZ only after a DNA damaging treatment. For three clones the site of integration and the degree of inducibility after UV treatment were determined by Southern blot and beta-galactosidase measurement respectively. One cell line (clone VI) showed a single integration site and a reproducible 3-fold induction of beta-galactosidase activity following UV irradiation. Fused transcripts were isolated from induced cells and a portion of the trapped gene was amplified by rapid amplification of cDNA ends. Sequence analysis and comparison with available gene and protein databanks revealed that the gene was novel.
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Affiliation(s)
- P Menichini
- CSTA-Laboratory of Mutagenesis, National Institute for Research on Cancer (IST), Largo Rosanna Benzi, 10, Genoa, Italy.
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57
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Trosko JE, Inoue T. Oxidative stress, signal transduction, and intercellular communication in radiation carcinogenesis. Stem Cells 1997; 15 Suppl 2:59-67. [PMID: 9368287 DOI: 10.1002/stem.5530150710] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
During the evolution of multicellular organisms, survival in an aerobic environment came about by adaptive responses, both to the endogenous oxidative metabolism within the cells of the organism as well as the chemicals and low-level radiation to which they are exposed. In addition to defense mechanisms shared with single-cell organisms, multicellular organisms are equipped with gap junctions which allow electrotonic and/or metabolic synchronization of processes between coupled cells. The connexin genes, which code for the proteins comprising the gap junctions, provide homeostatic regulation of cell proliferation, differentiation, and adaptive responses of individual cells through a mechanism of "gap junctional intercellular communication." The biological consequences of the response of a multicellular organism to low-level radiation exceeding the background level of oxidative damage to a cell in a tissue could be apoptosis, cell proliferation, or cell differentiation.
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Affiliation(s)
- J E Trosko
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, East Lansing, USA
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58
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Goldkorn T, Balaban N, Shannon M, Matsukuma K. EGF receptor phosphorylation is affected by ionizing radiation. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1358:289-99. [PMID: 9366260 DOI: 10.1016/s0167-4889(97)00063-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Eukaryotic cells respond to ionizing radiation with cell cycle arrest, activation of DNA repair mechanisms, and lethality. However, little is known about the molecular mechanisms that constitute these responses. Here we report that ionizing radiation enhances epidermal growth factor (EGF) receptor tyrosine phosphorylation in intact cells as well as in isolated membranes of A431 cells. Phosphoamino acid analysis revealed that ionizing radiation preferentially enhances tyrosine phosphorylation, while EGF enhances the phosphorylation of all three phosphoamino acids (serine, threonine and tyrosine) of the EGF receptor. In addition, radiation reduces the turnover rate of the EGF receptor, while EGF increases the rate of the receptor turnover and down-regulation. Moreover, the confined radiation-induced phosphorylation of tyrosine residues is inhibited by genistein, indicating that this phosphorylation of EGF receptor is due to protein tyrosine kinase activation. These studies provide novel insights into the capacity of radiation to modulate EGF receptor phosphorylation and function. The radiation-induced elevation in the EGF receptor tyrosine phosphorylation and the receptor's slower rate of turnover are discussed in terms of their possible role in cell growth and apoptosis modulation.
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Affiliation(s)
- T Goldkorn
- Department of Medicine, University of California, Davis School of Medicine, 95616, USA
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59
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Hardmeier R, Hoeger H, Fang-Kircher S, Khoschsorur A, Lubec G. Transcription and activity of antioxidant enzymes after ionizing irradiation in radiation-resistant and radiation-sensitive mice. Proc Natl Acad Sci U S A 1997; 94:7572-6. [PMID: 9207133 PMCID: PMC23863 DOI: 10.1073/pnas.94.14.7572] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The involvement of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase in radiobiological processes has been described at the enzyme activity level. We irradiated radiation-resistant (RR) and radiation-sensitive (RS) mice and studied antioxidant enzymes at the transcriptional and activity level. In addition, aromatic hydroxylation and lipid peroxidation parameters were determined to study radiation resistance at the oxidation level. RS BALB/c/J Him mice and RR C3H He/Him mice were whole-body-irradiated with x-rays at 2, 4, and 6 Gy and killed 5, 15, and 30 min after irradiation. mRNA was isolated from liver and hybridized with probes for antioxidant enzymes and beta-actin as a housekeeping gene control. Antioxidant enzyme activities were determined by standard assays. Parameters for aromatic hydroxylation (o-tyrosine) and lipid peroxidation (malondialdehyde) were determined by HPLC methods. Antioxidant transcription was unchanged in contrast to antioxidant activities; SOD and CAT activities were elevated within 15 min in RR animals but not in RS mice, at all doses studied. Glutathione peroxidase activity was not different between RR and RS mice and was only moderately elevated after irradiation. No significant differences were found between RR and RS animals at the oxidation level, although a radiation dose-dependent increase of oxidation products was detected in both groups. We found that ionizing irradiation led to increased antioxidant activity only minutes after irradiation in the absence of increased transcription of these antioxidant enzymes. RR animals show higher antioxidant enzyme activities than do RS mice, but oxidation products are comparable in RS and RR mice. As unchanged transcription of antioxidant enzymes could not have been responsible for the increased antioxidant enzyme activities, preformed antioxidant enzymes should have been released by the irradiation process. This would be in agreement with previous studies of preformed, stored SOD. The finding of higher SOD and CAT activities in RR than in RS animals could point to a role for these antioxidant enzymes for the process of radiation sensitivity.
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Affiliation(s)
- R Hardmeier
- Department of Pediatrics, University of Vienna, A 1090 Vienna, Austria
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60
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Beetz A, Messer G, Oppel T, van Beuningen D, Peter RU, Kind P. Induction of interleukin 6 by ionizing radiation in a human epithelial cell line: control by corticosteroids. Int J Radiat Biol 1997; 72:33-43. [PMID: 9246192 DOI: 10.1080/095530097143518] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The cutaneous radiation syndrome after therapeutic or accidental exposure of human skin to ionizing radiation (IR) is accompanied by inflammatory processes which are controlled partly by proinflammatory cytokines. Besides tumour necrosis factor (TNF)-alpha and interleukin (IL)1, the pluripotent cytokine IL-6 belongs to the key mediators of inflammation. So far, there are no reports about the regulation of IL-6 by IR in epidermal cells. As an in vitro model to study the effects of IR on IL-6 gene expression, we treated the human epithelial HeLa cell line with different single X-ray doses between 1 and 20 Gy. Twenty-four hours after irradiation the IL-6 secretion was dose-dependently enhanced as measured by ELISA. At the transcriptional level, a slight increase of IL-6 transcripts was already detectable 1 h after irradiation, with maximum levels at 2 h, and a decline to baseline levels between 8 and 24 h. Addition of the transcriptional inhibitor actinomycin D inhibited the inducibility of IL-6 mRNA by TPA and IR. As the IL-6 promoter contains multiple binding sites for activated glucocorticoid receptors within the 5' regulatory region, the potential modulation of IL-6 expression by the corticosteroids hydrocortisone, dexamethasone and mometasone furoate was included in our study to modify the radiation-induced stress response. All corticosteroids applied could efficiently downregulate TPA- or radiation-induced IL-6 expression on both gene expression and protein levels. Mometasone furoate, followed by dexamethasone, was found to be most effective at low concentrations (1 nM), whereas hydrocortisone had to be applied at about 100-fold higher concentrations to achieve comparable inhibition. This experimental model is aimed at understanding the molecular circuits following IR, and thus to provide a basis for the treatment of radiation effects in skin.
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Affiliation(s)
- A Beetz
- Department of Dermatology, University of Ulm, Germany
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61
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Dimberg Y. Effects of single dose and fractionated irradiation on foetal mouse brain aggregates. Toxicol In Vitro 1997; 11:193-200. [PMID: 20654305 DOI: 10.1016/s0887-2333(97)00010-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/24/1996] [Indexed: 11/19/2022]
Abstract
Foetal mouse brain cells were grown in vitro. 1 Gy X-irradiation was given as a single dose on culture day 2 (corresponding to embryonic day 17 in vivo) or in daily fractions (4 x 0.25 Gy), starting on day 2 in culture. The growth (size) and biochemical differentiation of the aggregates were studied up to day 40 in culture. Aggregates given a single dose (1 Gy) were smaller with lower protein and DNA amount than controls up to day 30-40 in culture. When the dose was fractionated, a partial recovery occurred by day 20, and values returned to control levels by day 30-40. The specific activity of acetylcholinesterase (AChE) was significantly higher after 10-20 days, in the irradiated (1 Gy) aggregates. In fractionated irradiated aggregates, the increase of specific activity of AChE was evident only after 10 days in culture. Compared with fractionated X-irradiation, where recovery was observed after 20-40 days in culture, a single dose of irradiation produced more permanent changes in the amounts of DNA and protein and in the size and neurochemical activities of aggregates.
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Affiliation(s)
- Y Dimberg
- Department of Radioecology, Swedish University of Agricultural Sciences, Box 7031, S-750 07 Uppsala, Sweden
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62
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Trosko JE. Challenge to the simple paradigm that 'carcinogens' are 'mutagens' and to the in vitro and in vivo assays used to test the paradigm. Mutat Res 1997; 373:245-9. [PMID: 9042406 DOI: 10.1016/s0027-5107(96)00203-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- J E Trosko
- Department of Pediatrics and Human Development, Michigan State University, East Lansing 48824, USA.
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63
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Sambani C, Thomou H, Kitsiou P. Stimulatory effect of low dose X-irradiation on the expression of the human T lymphocyte CD2 surface antigen. Int J Radiat Biol 1996; 70:711-7. [PMID: 8980669 DOI: 10.1080/095530096144608] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We investigated the early effects of low doses of ionizing radiation on the CD2 gene expression in normal human T lymphocytes in order to clarify if low-dose ionizing radiation has an enhancing and/or stimulatory effect on the immune response. The results indicate that even low doses of X-irradiation strongly enhance the appearance of CD2 antigen, both in PHA-stimulated and in resting T lymphocytes as demonstrated by a rosette assay or by immunofluorescence. Moreover, an accumulation of CD2 mRNA is observed in X-irradiated cells compared with non-irradiated, a fact that is attributed mainly to transcriptional activation of the CD2 gene and not to stabilization of preformed mRNA.
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Affiliation(s)
- C Sambani
- Institute of Nuclear Technology-Radiation Protection, National Centre for Scientific Research Demokritos, Paraskevi Attikis, Greece
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64
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Gajdusek CM, Tian H, London S, Zhou D, Rasey J, Mayberg MR. Gamma radiation effect on vascular smooth muscle cells in culture. Int J Radiat Oncol Biol Phys 1996; 36:821-8. [PMID: 8960508 DOI: 10.1016/s0360-3016(96)00297-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE Prior work in our laboratory demonstrated that external gamma irradiation administered within 48 h following balloon catheter carotid artery injury in rats produced a marked inhibition of intimal hyperplasia and restenosis. The current study used smooth muscle cells (SMC) in vitro to examine the radiation dose response and to investigate the cellular mechanism by which radiation inhibits SMC proliferation. METHODS AND MATERIALS Quiescent rat aortic SMC in plasma were refed with whole blood serum to stimulate synchronous proliferation and immediately irradiated with single fraction doses of 1.25-20 Gy. RESULTS Comparison between a micronucleus assay and a clonogenic assay indicated a dose-dependent inhibition of SMC growth, with an ED50 at 2-3 Gy. The micronucleus assay also demonstrated a dose-dependent increase in apparent chromosomal damage at 72 h after irradiation. Inhibition of SMC growth by radiation did not correlate with changes in intracellular or released mitogenic activity. Furthermore, there was no evidence of apoptosis in irradiated SMC up to 96 h after treatment. CONCLUSION Radiation likely inhibits SMC proliferation after arterial injury by a dose-dependent mechanism of lethal and/or sublethal cellular injury leading to clonogenic cell death.
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Affiliation(s)
- C M Gajdusek
- Department of Neurological Surgery, University of Washington, Seattle 98108, USA
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65
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Abstract
Bone pain is a common symptom in disseminated malignancy and may be difficult to manage effectively. Radiation is of proven benefit for pain palliation and there is growing interest in the therapeutic potential of bone-seeking radiopharmaceuticals. Clinical data relating to the use of phosphorus-32, strontium-89, samarium-153 EDTMP, rhenium-186 HEDP and tin-117m DTPA are reviewed in the context of the pathophysiology of metastatic bone pain. Possible mechanisms of action of palliative radiotherapy and, in particular, the theoretical role of early response genes are discussed. The application of Monte Carlo simulation to targeted radiotherapy for bone metastases may provide the basis for a clearer understanding of the microdosimetry and radiobiology of bone pain palliation and for reliable prediction of clinical response and toxicity.
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66
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67
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Weill D, Gay F, Tovey MG, Chouaib S. Induction of tumor necrosis factor alpha expression in human T lymphocytes following ionizing gamma irradiation. J Interferon Cytokine Res 1996; 16:395-402. [PMID: 8727080 DOI: 10.1089/jir.1996.16.395] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In this work, we present evidence that enriched human peripheral blood T lymphocytes, depleted of contaminating monocytes, rapidly express tumor necrosis factor alpha (TNF-alpha) mRNA when exposed to low doses of gamma-irradiation. In total PBL, TNF-alpha mRNA accumulation increased threefold as early as 30 minutes following exposure to 4 Gy and then declined to the baseline level by 3-5 h, as measured by the reverse transcriptase-polymerase chain reaction (RT-PCR). The increase in TNF-alpha mRNA was also observed in populations of enriched T cells and decreased when the dose of irradiation was increased to 10 Gy, strongly suggesting that T lymphocytes, the most radiosensitive cells of the body, contributed directly to the increase of TNF-alpha mRNA. A good correlation was found between mRNA expression and TNF-alpha protein secretion. Interestingly, a eightfold increase in glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA accumulation was also detected in both PBL and enriched T cells irradiated at 4 Gy for 3 h compared with unirradiated cells. This irradiation effect was almost completely abolished, however, following exposure to 10 Gy. Together these data suggest that T cells are responsible for the irradiation-induced expression of TNF-alpha and GAPDH.
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Affiliation(s)
- D Weill
- Laboratoire de Génétique Moléculaire et Biologie du Développement, Villejuif, France
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68
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Lohrer HD. Regulation of the cell cycle following DNA damage in normal and Ataxia telangiectasia cells. EXPERIENTIA 1996; 52:316-28. [PMID: 8620934 DOI: 10.1007/bf01919534] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A proportion of the population is exposed to acute doses of ionizing radiation through medical treatment or occupational accidents, with little knowledge of the immediate effects. At the cellular level, ionizing radiation leads to the activation of a genetic program which enables the cell to increase its chances of survival and to minimize detrimental manifestations of radiation damage. Cytotoxic stress due to ionizing radiation causes genetic instability, alterations in the cell cycle, apoptosis, or necrosis. Alterations in the G1, S and G2 phases of the cell cycle coincide with improved survival and genome stability. The main cellular factors which are activated by DNA damage and interfere with the cell cycle controls are: p53, delaying the transition through the G1-S boundary; p21WAF1/CIP1, preventing the entrance into S-phase; proliferating cell nuclear antigen (PCNA) and replication protein A (RPA), blocking DNA replication; and the p53 variant protein p53 as together with the retinoblastoma protein (Rb), with less defined functions during the G2 phase of the cell cycle. By comparing a variety of radioresistant cell lines derived from radiosensitive ataxia telangiectasia cells with the parental cells, some essential mechanisms that allow cells to gain radioresistance have been identified. The results so far emphasise the importance of an adequate delay in the transition from G2 to M and the inhibition of DNA replication in the regulation of the cell cycle after exposure to ionizing radiation.
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Affiliation(s)
- H D Lohrer
- Gray Laboratory, Mount Vernon Hospital, Northwood, United Kingdom
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69
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Abstract
The reaction kinetics of radioadaptive response of low doses of X-rays have been studied in quiescent cultured mouse cells. Mouse m5S cells pre-exposed in G1 to low doses of X-rays became insensitive to the induction of chromosome aberrations, mutation toward 6-thioguanine resistance, and cell killing. Adapted cells were, however, more susceptible to morphological transformation by subsequent high challenging doses of X-rays. The cytogenetic adaptation, which lasted about 20 h pertained to a narrow dose range. X-ray doses below and above 0.1 Gy appeared to be recognized as different signals; higher doses of X-rays were incapable of inducing adaptation and rapidly extinguished the adapted condition. Treatment with 12-O-tetradecanoyl-phorbol 13-acetate (TPA) and hydrogen peroxide, but not the xanthine/xanthine oxidase superoxide-generating system, mimicked X-rays in inducing adaptation when applied at low doses. Over-exposure to TPA or inhibitors of protein kinase C (PKC) abrogated the adaptive response to X-rays, providing evidence for the involvement of a PKC-mediated signalling pathway. The lack of radioadaptive response in a tumorigenic variant, clone 6110, and its restoration in the morphological revertant obtained by introducing human chromosome 11 further suggested that interference of signalling pathways may alter radioadaptive responses in malignant cells.
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Affiliation(s)
- M S Sasaki
- Radiation Biology Centre, Kyoto University, Japan
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70
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Vijayakumar S, Quadri SF, Sen S, Vaida F, Ignacio L, Weichselbaum RR. Measurement of weekly prostate specific antigen levels in patients receiving pelvic radiotherapy for nonprostatic malignancies. Int J Radiat Oncol Biol Phys 1995; 32:189-95. [PMID: 7536721 DOI: 10.1016/0360-3016(94)00460-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE To study the response of nonmalignant prostatic tissue to ionizing irradiation in terms of the resultant changes in serum prostate specific antigen (PSA) levels. METHODS AND MATERIALS Weekly serum PSA values were determined during radiotherapy (RT) in nine patients ("treatment group") without clinical evidence of prostate cancer (PC), and who received pelvic RT for other indications. Slopes for the rate of change in PSA was determined using model: log PSA = beta 0 + beta 1*week + beta 2*week2 + error. These results are compared with 17 normal volunteers ("control group") who were not exposed to ionizing irradiation. An attempt is made to compare any similarities and differences in subsets of 64 T1-T4N0M0 PC patients who received pelvic RT. RESULTS An elevation in the serum PSA levels were noted in eight of nine patients in the "treatment group" with a median time of 4.2 weeks to reach the maximum serum PSA values. After an initial increase, PSA values declined. In some patients, manifold increase in PSA was noted, for example, from 1.8 to 13.5 ng/ml and 3.3 to 9.8 ng/ml in two patients. The PSA increase ranged from 50-650%. The median slope was 0.601 week-1 (range 0.192-3.045 week-1). No such increases were seen in the "control group" (median slope = 0.03 week-1; range, 0.18-0.13 week-1). When differences between the mean increase/decrease for each week compared to pretreatment values were analyzed, the irradiated group had statistically significant elevations in the PSA for weeks 3 (p = 0.034), 4 (p = 0.035), and 5 (p = 0.024). A similar trend of increasing PSA levels during radiotherapy was noted in prostate cancer patients whose initial PSA values were < or = 20 ng/ml: whereas positive slopes (i.e., increasing PSA levels during radiotherapy course) was seen in 7.1% of those with > 20 ng/ml preradiotherapy PSA values, such trends were seen in 52.7% of those with < or = 20 ng/ml preradiotherapy PSA values. CONCLUSIONS (a) Incidental exposure of noncancerous prostate to ionizing irradiation appears to lead to an initial elevation followed by a decline in serum PSA. (b) Similar elevations in serum PSA levels are seen in over 50% of prostate cancer patients with < or = 20 ng/ml pretreatment PSA. (c) Acinal cell death and sudden release of PSA into the circulation is the most likely explanation for our observations, although other mechanism cannot be excluded. (d) Our observations have to be considered in modeling PSA kinetics induced by RT and in correlating such kinetics to long-term outcomes. (e) Our findings in the control group indicate that there appears to be no significant variation in serum PSA over many weeks under physiological conditions in normal healthy ambulatory men.
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Affiliation(s)
- S Vijayakumar
- Michael Reese/University of Chicago Center for Radiation Therapy, Department of Radiation and Cellular Oncology, University of Chicago, IL, USA
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71
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Matsuo T, Ohtsuru A, Ito M, Komatsu K, Okumura Y, Numba H, Yamashita S, Sekine I. Inhibition of epidermal growth factor binding system by ionizing radiation in A431 human squamous carcinoma cells. Cancer Lett 1995; 89:153-9. [PMID: 7889523 DOI: 10.1016/0304-3835(95)03685-p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
To elucidate the effect of ionizing radiation on the membrane anchored signal transduction, the binding of 125I epidermal growth factor (EGF) to its receptor (EGF-R) and the EGF-dependent EGF-R tyrosine phosphorylation were examined in a human squamous cell carcinoma cell line, A431. The significant suppression of 125I EGF binding to A431 cells was observed from 3-5 h after 10 Gy irradiation, whereas this inhibition was not observed both in non-irradiated and in 5 Gy-irradiated cells. This phenomenon was mediated by the protein kinase C pathway, because the inhibition was not observed in cells which had been pretreated with phorbol ester and treated with an inhibitor of the enzyme, H7. Scatchard analysis showed that the receptor affinity was decreased. In contrast, the level of EGF-dependent EGF-R-tyrosine phosphorylation was not decreased, compared with non-irradiated cells. These results suggest that ionizing radiation may modulate the function of EGF/EGF-R interaction through the direct activation of protein kinase C.
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Affiliation(s)
- T Matsuo
- Department of Pathology, Nagasaki University School of Medicine, Japan
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72
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Abstract
Inherent cellular radioresistance plays a critical role in the failure of radiotherapy. Although the consequences of radioresistance are well known, the molecular, biological, and cellular bases of radioresistance remain a mystery. We propose that genomic instability, the increased rate of acquisition of alterations in the mammalian genome, can directly modulate cells' sensitivity to radiation. In particular, destabilization of chromosomes occurring as a consequence of genomic instability may result in enhanced 'plasticity of the genome'. This increased plasticity of the genome allows cells to better adapt to changes in local environment(s) during tumor progression, or improve cell survival following exposure to DNA damage encountered during radiotherapy protocols, thereby contributing to radioresistant cell populations found in tumors both before and after radiotherapy.
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Affiliation(s)
- W F Morgan
- Laboratory of Radiobiology and Environmental Health, University of California, San Francisco, USA
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73
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Abstract
Radiotherapy remains an important component of the management of malignant disease. Especially when combined with cytotoxic chemotherapy, limited surgical excision, or both, irradiation has been shown to control disease in the primary site and regional nodes without the need for surgical extirpation as frequently as in past years. New developments in three-dimensional treatment planning and the precise delivery of high-dose radiation promise to increase the benefit of radiation treatment. Finally, molecular studies of the cell's response to radiation and the phenomena of DNA damage and repair are providing explanations for heretofore unexplained radiobiologic observations. Such research is laying the groundwork for targeted manipulation of the cell's response to radiation, which will be tested in the near future.
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Affiliation(s)
- A S Lichter
- Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor 48109-0010
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74
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de Toledo SM, Azzam EI, Gasmann MK, Mitchel RE. Use of semiquantitative reverse transcription-polymerase chain reaction to study gene expression in normal human skin fibroblasts following low dose-rate irradiation. Int J Radiat Biol 1995; 67:135-43. [PMID: 7884281 DOI: 10.1080/09553009514550171] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
One way to study the effect of radiation on gene expression is to monitor changes in the levels of specific messenger RNAs. We describe the use of reverse transcription-polymerase chain reaction (RT-PCR) analysis, a faster and more sensitive procedure than the traditional techniques to monitor RNA levels. Using RT-PCR, we confirmed previous results showing increased levels of GADD45 transcripts after high dose-rate X-irradiation in normal human fibroblasts. No differences were observed in the transcript levels of beta-ACTIN, beta-MICROGLOBULIN, Cu-Zn SUPEROXIDE DISMUTASE (SOD-1) and CATALASE. In cells exposed to 3-6 Gy low dose-rate gamma-irradiation we observed increased levels of the GADD45 transcript and lower transcript levels of the genes TOPOISOMERASE II alpha, FACC, CYCLIN A and CYCLIN B. No differences were detected in the transcript levels of beta-ACTIN, beta-MICROGLOBULIN, SOD-1, URACYL-DNA GLYCOSYLASE, CYCLIN C, CYCLIN E, CYCLIN D1, CYCLIN D2, CYCLIN D3, TOPOISOMERASE I and TOPOISOMERASE II beta.
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Affiliation(s)
- S M de Toledo
- Radiation Biology and Health Physics Branch, AECL Research, ON, Canada
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75
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Morgan GW, Breit SN. Radiation and the lung: a reevaluation of the mechanisms mediating pulmonary injury. Int J Radiat Oncol Biol Phys 1995; 31:361-9. [PMID: 7836090 DOI: 10.1016/0360-3016(94)00477-3] [Citation(s) in RCA: 184] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recent data from several investigators, including our unit, have provided additional information on the etiology of radiation-induced lung damage. These data suggest that there are two quite separate and distinct mechanisms involved: (a) classical radiation pneumonitis, which ultimately leads to pulmonary fibrosis is primarily due to radiation-induced local cytokine production confined to the field of irradiation; and (b) sporadic radiation pneumonitis, which is an immunologically mediated process resulting in a bilateral lymphocytic alveolitis that results in an "out-of-field" response to localized pulmonary irradiation. Both animal experiments and human studies show that classical radiation pneumonitis has a threshold dose and a narrow sigmoid dose-response curve with increasing morbidity and mortality over a very small dose range. Clinical pneumonitis rarely causes death, whereas in the animal and human studies of classical radiation pneumonitis, all subjects will eventually suffer irreversible pulmonary damage and death. The description of classical radiation pneumonitis is that of an acute inflammatory response to lung irradiation, which is confined to the area of irradiation. Recent studies have also shown that irradiation induces gene transcription and results in the induction and release of proinflammatory cytokines and fibroblast mitogens in a similar fashion to other chronic inflammatory states, and which ultimately results in pulmonary fibrosis. The description of classical radiation pneumonitis does not adequately explain the following observed clinical characteristics: (a) the unpredictable and sporadic onset; (b) the occurrence in only a minority of patients; (c) the dyspnoea experienced, which is out of proportion to the volume of lung irradiated; and (d) the resolution of symptoms without sequelae in the majority of patients. We have demonstrated a bilateral lymphocytic alveolitis of activated T lymphocytes and a diffuse increase in gallium lung scan uptake in patients studied before and 4 to 6 weeks after strictly unilateral lung irradiation. This is suggestive of a hypersensitivity pneumonitis, which gives rise to an "out-of-field" response to localized lung irradiation and hence more accurately describes the clinical picture of radiation pneumonitis. Reevaluation of the mechanisms of pulmonary injury from irradiation suggest that (a) a new term, sporadic radiation pneumonitis, should be introduced to describe the clinical picture of radiation pneumonitis, which is not adequately explained by the classical description and is quite clearly an entirely different process; and (b) that the chronic response to localized lung irradiation that leads to pulmonary fibrosis is largely mediated through the induction and release of tissues cytokines.
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Affiliation(s)
- G W Morgan
- Department of Radiation Oncology, St. Vincent's Hospital, Sydney, NSW, Australia
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76
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77
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78
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Behrends U, Peter RU, Hintermeier-Knabe R, Eissner G, Holler E, Bornkamm GW, Caughman SW, Degitz K. Ionizing radiation induces human intercellular adhesion molecule-1 in vitro. J Invest Dermatol 1994; 103:726-30. [PMID: 7963663 DOI: 10.1111/1523-1747.ep12398607] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Intercellular adhesion molecule-1 (ICAM-1) plays a central role in various inflammatory reactions and its expression is readily induced by inflammatory stimuli such as cytokines or ultraviolet irradiation. We have investigated the effect of ionizing radiation (IR) on human ICAM-1 expression in human cell lines and skin cultures. ICAM-1 mRNA levels in HL60, HaCaT, and HeLa cells were elevated at 3-6 h after irradiation and increased with doses from 10-40 Gy. The rapid induction of ICAM-1 occurred at the level of transcription, was independent of de novo protein synthesis, and did not involve autocrine stimuli including tumor necrosis factor-alpha and interleukin-1. IR also induced ICAM-1 cell surface expression within 24 h. Immunohistologic analysis of cultured human split skin revealed ICAM-1 upregulation on epidermal keratinocytes and dermal microvascular endothelial cells 24 h after exposure to 6 Gy. In conclusion, we propose ICAM-1 as an important radiation-induced enhancer of immunologic cell adhesion, which contributes to inflammatory reactions after local and total body irradiation.
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Affiliation(s)
- U Behrends
- Institute of Clinical Molecular Biology and Tumor Genetics, GSF, München, Germany
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79
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Abstract
Selected aspects of radiation-induced cell death, connected with signal transduction pathways are reviewed. Cell death is defined as insufficiency of the cellular signal transducing system to maintain the cell's physiological functions. The insufficiency may be due to impaired signal reception and/or transduction, lack or erroneous transcription activation, and eventual cellular 'misexpression' of the signal. The molecular basis of this insufficiency would be damage to genomic (but also other cellular) structures and closing of specific signalling pathways or opening of others (like those leading to apoptosis). I describe experimental data that suggest an important role of RAS/NF1 and p53/p105 Rb proteins in cell cycle control-coupled responses to DNA damage.
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Affiliation(s)
- I Szumiel
- Department of Radiobiology and Health Protection, Institute of Nuclear Chemistry and Technology, Warszawa, Poland
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80
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Abstract
Previously, we have shown that integrated copies of polyoma DNA can be induced to replicate in rat fibroblasts (H3 cells) exposed to a DNA-damaging agent. In the current study, we demonstrate that UV-irradiation of mouse fibroblasts (WOP cells), transiently transfected with polyoma DNA, results in repression of polyoma replication. Cotransfection of oligomers representing wild-type but not mutated forms of the PEBP2 target sequence restored levels of viral replication indicating a role of PEBP2 binding proteins in mediating this effect. DNA-binding assays revealed that a different subset of complexes was formed with the PEBP2 target sequence when nuclear proteins from sham and UV-irradiated WOP and H3 cells were compared, suggesting that the activities of PEBP2 binding proteins are differentially regulated upon UV-irradiation in these two cell types. The ability of PEBP2 to modulate polyoma replication following UV-irradiation in WOP cells suggests a potential role of PEBP2 proteins in the cellular response to DNA damage.
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Affiliation(s)
- S E Rutberg
- Molecular Carcinogenesis Program, American Health Foundation, Valhalla, NY 10595
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81
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Schmidt-Ullrich RK, Valerie KC, Chan W, McWilliams D. Altered expression of epidermal growth factor receptor and estrogen receptor in MCF-7 cells after single and repeated radiation exposures. Int J Radiat Oncol Biol Phys 1994; 29:813-9. [PMID: 8040028 DOI: 10.1016/0360-3016(94)90570-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE Studies on radiation-induced changes in gene expression are likely to be very important in developing a better understanding of cellular responses to ionizing radiation. While there is some information on the activation of cellular signal transduction pathways after radiation, few late reacting target genes have been identified. This study focuses on the characterization of expression modulation of two critical growth regulatory genes, estrogen receptor and epidermal growth factor-receptor in malignant mammary epithelial cells in response to single and repeated ionizing radiation exposures. METHODS AND MATERIALS MCF-7 cells were used for single radiation exposure (2-50 Gy) experiments and MCF-IR-3 cells, generated by exposure to cumulative doses of 60 Gy in 2 Gy fractions, respectively, were used to study the effects of repeated exposures. Steady-state messenger ribonucleic acid levels for estrogen receptor, epidermal growth factor-receptor, and transforming growth factor-alpha were determined by ribonucleic acid protection experiments. Estrogen receptor and epidermal growth factor-receptor protein expression was quantitated by competitive binding studies with 3H-estradiol and 125I-EGF. RESULTS MCF-IR-3 cells showed a permanent three-fold down-regulation of the estrogen receptor messenger ribonucleic acid and protein, while epidermal growth factor-receptor was upregulated about nine-fold. Epidermal growth factor-receptor was substantially up-regulated in MCF-7 cells, at both the mRNA and protein levels, within 24 h of a single 2 Gy exposures, while there was a two-fold concomitant increase in transforming growth factor-alpha messenger ribonucleic acid expression. A decrease in estrogen receptor messenger ribonucleic acid and protein was suggested only after higher doses of single radiation exposures. CONCLUSION Single and repeated radiation exposures modulate the expression of two critical growth promoting genes, estrogen receptor and epidermal growth factor-receptor, in MCF-7 cells. The inverse expression of estrogen receptor and epidermal growth factor-receptor established for estrogen receptor-positive malignant mammary epithelial cells is maintained in MCF-7 cells after single and repeated exposures suggesting that radiation acts through common regulatory circuits and may modulate the cellular phenotype.
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82
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Wojewodzka M, Walicka M, Sochanowicz B, Szumiel I. Calcium antagonist, TMB-8, prevents the induction of adaptive response by hydrogen peroxide or X-rays in human lymphocytes. Int J Radiat Biol 1994; 66:99-109. [PMID: 8027616 DOI: 10.1080/09553009414550981] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Treatment of human lymphocytes with hydrogen peroxide (10 microM, 30 min, 37 degrees C in PBS) or with 1 cGy X-rays evoked about a 30% decrease in the frequency of micronuclei upon subsequent X-irradiation (1.5 Gy). In addition to a lower micronuclei frequency, we also found an increase in the sedimentation distance of the nucleoids, when measured 90 min (duration of the isolation procedure carried out at 4 degrees C) after the adaptive dose (hydrogen peroxide or X-rays) and preceding the challenge dose. To test whether Ca2+ is involved in the induction of the adaptive response pathway, we treated cells with the calcium chelator, EGTA. When EGTA was given at the same time as the adaptive dose, it prevented the development of the adaptive response. In addition, the calcium antagonist, TMB-8, also prevented the development of the adaptive response as it prevented the reduction of both micronuclei and increased nucleoid sedimentation. Cellular treatment with TMB-8 increased the free [Ca2+] by 40%, when given together with hydrogen peroxide. The faster sedimenting nucleoids from adapted cells were also examined by ethidium bromide titration; there was no indication of any change in supercoil density or loop size. Psi-tectorigenin, an inhibitor of phosphatidylinositol turnover, did not modify the adaptive response, indicating that inositol (1,4,5)-trisphosphate is not involved in the induction of the adaptive response, but free Ca2+ ions are.
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Affiliation(s)
- M Wojewodzka
- Department of Radiobiology and Health Protection, Institute of Nuclear Chemistry and Technology, Warsaw, Poland
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83
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Bump EA, Braunhut SJ, Palayoor ST, Medeiros D, Lai LL, Cerce BA, Langley RE, Coleman CN. Novel concepts in modification of radiation sensitivity. Int J Radiat Oncol Biol Phys 1994; 29:249-53. [PMID: 8195015 DOI: 10.1016/0360-3016(94)90270-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE To determine whether biological effects of radiation, such as apoptosis, that differ from classical clonogenic cell killing, can be modified with agents that would not be expected to modify classical clonogenic cell killing. This would expand the range of potential modifiers of radiation therapy. METHODS AND MATERIALS EL4 murine lymphoma cell apoptosis was determined by electrophoretic analysis of deoxyribonucleic acid (DNA) fragmentation. DNA was extracted 24 h after irradiation or addition of inducing agents. Modifiers of radiation-induced apoptosis were added immediately after irradiation. The effects of radiation on wounded endothelial monolayers were studied by scraping a line across the monolayer 30 min after irradiation. Cell detachment was used as an endpoint to determine the protective effect of prolonged exposure to retinol prior to irradiation. RESULTS EL4 cell apoptosis can be induced by tert-butyl hydroperoxide or the glutathione oxidant SR-4077. Radiation-induced EL4 cell apoptosis can be inhibited with 3-aminobenzamide, an agent that sensitizes cells to classical clonogenic cell killing. Radiation-induced endothelial cell detachment from confluent monolayers can be modified by pretreatment with retinol. CONCLUSION These results raise the possibility that radiation could induce apoptosis by an oxidative stress mechanism that is different from that involved in classical clonogenic cell killing. These and other recent findings encourage the notion that differential modification of classical clonogenic cell killing and other important endpoints of radiation action may be possible.
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Affiliation(s)
- E A Bump
- Joint Center for Radiation Therapy, Harvard Medical School, Boston, MA 02115
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84
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Affiliation(s)
- A M Cassoni
- Department of Oncology, University College London, Middlesex Hospital, U.K
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85
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Abstract
DNA damage induced by ionizing radiation can result in gene mutation, gene amplification, chromosome rearrangements, cellular transformation, and cell death. Although many of these changes may be induced directly by the radiation, there is accumulating evidence for delayed genomic instability following X-ray exposure. We have investigated this phenomenon by studying delayed chromosomal instability in a hamster-human hybrid cell line by means of fluorescence in situ hybridization. We examined populations of metaphase cells several generations after expanding single-cell colonies that had survived 5 or 10 Gy of X rays. Delayed chromosomal instability, manifested as multiple rearrangements of human chromosome 4 in a background of hamster chromosomes, was observed in 29% of colonies surviving 5 Gy and in 62% of colonies surviving 10 Gy. A correlation of delayed chromosomal instability with delayed reproductive cell death, manifested as reduced plating efficiency in surviving clones, suggests a role for chromosome rearrangements in cytotoxicity. There were small differences in chromosome destabilization and plating efficiencies between cells irradiated with 5 or 10 Gy of X rays after a previous exposure to 10 Gy and cells irradiated only once. Cell clones showing delayed chromosomal instability had normal frequencies of sister chromatid exchange formation, indicating that at this cytogenetic endpoint the chromosomal instability was not apparent. The types of chromosomal rearrangements observed suggest that chromosome fusion, followed by bridge breakage and refusion, contributes to the observed delayed chromosomal instability.
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86
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Sendler A, Kaffenberger W, Nuyken I, van Beuningen D. Proliferation kinetics and PCNA expression of HL-60 cells following ionizing irradiation and granulocytic differentiation. Cell Prolif 1993; 26:531-43. [PMID: 9116120 DOI: 10.1111/j.1365-2184.1993.tb00031.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The human promyelocytic leukaemia cell line, HL-60, was investigated with regard to proliferation and terminal differentiation following irradiation. The cells were X-irradiated and induced with 1.25% dimethyl sulfoxide (DMSO) towards the granulocytic lineage. Proliferation was measured via cell growth, clonogenicity and the bromodeoxyuridine/DNA incorporation assay. Immunohistochemical detection of proliferating cell nuclear antigen (PCNA) expression was used to discriminate cycling from non-cycling cells. The differentiation obtained was proved by testing for the immune function of the respiratory burst (NBT reduction test). The HL-60 cells studied revealed a high radiosensitivity (D0 = 0.63 Gy). After induction with DMSO, declines in cell growth, clonogenicity and PCNA positivity of the cells indicated a decrease in proliferation and an increase in differentiation. Starting on day 2 in culture, irradiation after seeding with 1 Gy accelerated the loss of the PCNA expression in induced cells (46% v. 3% PCNA-negative control cells on day 3). Induced cells gained the capability of exerting the respiratory burst, which was found to be dose-dependent radiosensitive (42%, and 12% NBT-positive cells after 1 and 2 Gy, respectively, v. 53% NBT-positive control cells on day 8). Subpopulations in the cell line were evident in all parameters investigated. We discuss the HL-60 cell, not only as a model comparable to human progenitor cells, but also as a suitable tool in radiobiological research with regard to proliferation and differentiation following ionizing irradiation.
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Affiliation(s)
- A Sendler
- Institute of Radiobiology, Federal Armed Forces Medical Academy, Munich, Germany
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87
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Abstract
DNA damage induced by ionizing radiation can result in gene mutation, gene amplification, chromosome rearrangements, cellular transformation, and cell death. Although many of these changes may be induced directly by the radiation, there is accumulating evidence for delayed genomic instability following X-ray exposure. We have investigated this phenomenon by studying delayed chromosomal instability in a hamster-human hybrid cell line by means of fluorescence in situ hybridization. We examined populations of metaphase cells several generations after expanding single-cell colonies that had survived 5 or 10 Gy of X rays. Delayed chromosomal instability, manifested as multiple rearrangements of human chromosome 4 in a background of hamster chromosomes, was observed in 29% of colonies surviving 5 Gy and in 62% of colonies surviving 10 Gy. A correlation of delayed chromosomal instability with delayed reproductive cell death, manifested as reduced plating efficiency in surviving clones, suggests a role for chromosome rearrangements in cytotoxicity. There were small differences in chromosome destabilization and plating efficiencies between cells irradiated with 5 or 10 Gy of X rays after a previous exposure to 10 Gy and cells irradiated only once. Cell clones showing delayed chromosomal instability had normal frequencies of sister chromatid exchange formation, indicating that at this cytogenetic endpoint the chromosomal instability was not apparent. The types of chromosomal rearrangements observed suggest that chromosome fusion, followed by bridge breakage and refusion, contributes to the observed delayed chromosomal instability.
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Affiliation(s)
- B A Marder
- Laboratory of Radiobiology and Environmental Health, University of California, San Francisco 94143-0750
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88
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Gubits RM, Geard CR, Schiff PB. Expression of immediate early genes after treatment of human astrocytoma cells with radiation and taxol. Int J Radiat Oncol Biol Phys 1993; 27:637-42. [PMID: 7901186 DOI: 10.1016/0360-3016(93)90390-h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE The promising chemotherapeutic agent, taxol, has been shown to sensitize the G18 line of human astrocytoma cells to ionizing radiation. The present studies were performed to identify specific changes in gene expression associated with this altered sensitivity. METHODS AND MATERIALS The radioresistant, grade 3 human astrocytoma cell line, G18, was exposed for varying periods of time to treatment with taxol, tetradecanoyl phorbol acetate (TPA), serum, isoproterenol, dibutyryl cyclic adenosine monophosphate, or ionizing radiation alone or in combination with taxol pretreatment. Ribonucleic acid samples from the cells were monitored for the expression of a group of immediate early genes (IEGs), including c-fos, c-jun, TIS1, TIS7, TIS8, TIS11 and TIS21, by northern blot hybridization analysis. RESULTS Transient immediate early gene induction was observed after treatment of G18 cells with tetradecanoyl phorbol acetate, serum, isoproterenol, or ionizing radiation, but not after treatment with taxol. Of the seven immediate early genes analyzed, all but TIS7 were found to be inducible by one or more of the treatments. Only TIS8 (also known as egr-1 or zif268) was significantly inducible by radiation, and this transient induction was decreased by at least four-fold by pretreatment for 24 hr with a dose of taxol that was previously shown to block 96.5% of the cells in G2/M and enhance radiosensitivity. CONCLUSION The products of immediate early genes, which are induced transiently in cells in response to a variety of treatments, including growth factors, neurotransmitters, and irradiation with UV light or X rays, are thought to initiate a cascade of genetic responses to alterations in cellular environment. The present results demonstrate a dramatic attenuation in one immediate early gene response in association with a treatment that enhances radiosensitivity in a refractory human brain tumor line.
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Affiliation(s)
- R M Gubits
- Dept. of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY 10032
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89
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Induction of cellular p53 activity by DNA-damaging agents and growth arrest. Mol Cell Biol 1993. [PMID: 8321226 DOI: 10.1128/mcb.13.7.4242] [Citation(s) in RCA: 266] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The tumor suppressor p53 can function as a sequence-specific transcription factor and is required for activation by ionizing radiation (IR) of one or more downstream effector genes, such as the human GADD45 gene. One important consequence of IR that is probably mediated by these downstream effector genes is activation of the p53-mediated G1 cell cycle checkpoint. While the induction of reporter constructs containing p53-binding sites has already been demonstrated with p53 expression vectors, we have now demonstrated the direct activation of such a construct after treatment of the human RKO line, which has a normal p53 phenotype, with various types of DNA-damaging agents and also after growth arrest produced by medium depletion (starvation). IR, UV radiation, and methylmethane sulfonate were found to induce p53 activity when a stably integrated reporter construct containing functional p53-binding sites was used and also in mobility shift assays with a p53-binding site from the GADD45 gene, and IR-inducible gene previously associated with growth arrest. The same cell treatments that induced this p53 activity also caused an increase in cellular p53 protein levels. The response in cells lacking normal p53 or in RKO cells expressing a dominant negative mutant p53 was markedly reduced. Interestingly, the spectrum of effective inducing agents for the above-described experiments was similar to that which induces GADD45 either in cells with a normal p53 status or, with the exception of IR, in cells lacking normal p53. These results indicate a role for p53 in the IR pathway, which is completely p53 dependent, and in other genotoxic stress responses, in which p53 has a cooperative effect but is not required.
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90
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Abstract
The scientific knowledge that is emerging in all fields of medicine is rapidly changing our understanding of the concepts in radiation oncology. In this review, some of the classic radiation biology theories and models are examined and newer 'models' are illustrated. The ability of radiation oncologists to remain current with the newer scientific findings is essential to the development of improved therapeutic strategies and, importantly, to the proper balance between investment in technology and biology.
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Affiliation(s)
- C N Coleman
- Joint Center for Radiation Therapy, Harvard Medical School, Boston, MA 02115
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91
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Zhan Q, Carrier F, Fornace AJ. Induction of cellular p53 activity by DNA-damaging agents and growth arrest. Mol Cell Biol 1993; 13:4242-50. [PMID: 8321226 PMCID: PMC359974 DOI: 10.1128/mcb.13.7.4242-4250.1993] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The tumor suppressor p53 can function as a sequence-specific transcription factor and is required for activation by ionizing radiation (IR) of one or more downstream effector genes, such as the human GADD45 gene. One important consequence of IR that is probably mediated by these downstream effector genes is activation of the p53-mediated G1 cell cycle checkpoint. While the induction of reporter constructs containing p53-binding sites has already been demonstrated with p53 expression vectors, we have now demonstrated the direct activation of such a construct after treatment of the human RKO line, which has a normal p53 phenotype, with various types of DNA-damaging agents and also after growth arrest produced by medium depletion (starvation). IR, UV radiation, and methylmethane sulfonate were found to induce p53 activity when a stably integrated reporter construct containing functional p53-binding sites was used and also in mobility shift assays with a p53-binding site from the GADD45 gene, and IR-inducible gene previously associated with growth arrest. The same cell treatments that induced this p53 activity also caused an increase in cellular p53 protein levels. The response in cells lacking normal p53 or in RKO cells expressing a dominant negative mutant p53 was markedly reduced. Interestingly, the spectrum of effective inducing agents for the above-described experiments was similar to that which induces GADD45 either in cells with a normal p53 status or, with the exception of IR, in cells lacking normal p53. These results indicate a role for p53 in the IR pathway, which is completely p53 dependent, and in other genotoxic stress responses, in which p53 has a cooperative effect but is not required.
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Affiliation(s)
- Q Zhan
- Laboratory of Molecular Pharmacology, National Cancer Institute, Bethesda, Maryland 20892
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92
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Kavanagh BD, Halperin EC, Nilaver G. Syndrome of inappropriate secretion of antidiuretic hormone in a patient with carcinoma of the nasopharynx. Cancer 1993; 72:299. [PMID: 8508422 DOI: 10.1002/1097-0142(19930701)72:1<299::aid-cncr2820720152>3.0.co;2-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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93
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Cao J, Wells RL, Elkind MM. Neoplastic transformation of C3H mouse embryo cells, 10T1/2: cell-cycle dependence for 50 kV X-rays and UV-B light. Int J Radiat Biol 1993; 64:83-92. [PMID: 8102174 DOI: 10.1080/09553009314551131] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The variation of neoplastic transformation induced by 50 kV X-rays, and by solar-simulating UV-B light, was studied through the cell cycle of C3H mouse embryo cells designated 10T1/2. A mitotic shake-off method was used to harvest mitotic cells. The progression through the cell cycle of initially mitotic cells was followed as a function of time by flow cytometry, DNA labelling for passage through S-phase, and growth curves for cell number. At 2-3 h after shake-off, about 90% of the cells were in early G1-phase and by 15 h 60-70% of cells had reached S-phase. For 2.5 Gy, the transformation frequency per viable cell in M-phase was some five times higher than in S-phase. In contrast, at similar survival levels, UV-B light is less efficient in transforming mitotic cells. For both types of radiation, the frequency of neoplastic transformation per viable cell was roughly inversely proportional to survival.
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Affiliation(s)
- J Cao
- Department of Radiological Health Sciences, Colorado State University, Fort Collins 80523
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94
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Abstract
Using bone marrow cells of whole body irradiated mice, the cytogenetic adaptive response induced by low conditioning doses of gamma-rays was investigated. The conditioning doses (0.025 and 0.05 Gy) were given at a dose-rate of 1.67 Gy/min. The challenging dose of 1 Gy was given at a dose-rate of 0.045 Gy/s. The challenging dose was given at different time intervals after the conditioning dose. The time intervals between the conditioning dose and challenging dose were 2, 7.5, 13, 18.5 and 24 h. When the time interval between the conditioning dose and the challenging dose was 2 h, both conditioning doses (0.025 and 0.05 Gy) reduced the frequency of MNPCEs and chromosomal aberrations in the bone marrow cells. The data collected at different time intervals (7.5, 13, 18.5 h) reveal that the radioadaptive response persisted for a longer time when the lower conditioning dose (0.025 Gy) was given. With the higher conditioning dose (0.05 Gy), the radioadaptive response disappeared after a time interval of 13 h. When the time interval between the conditioning dose and the challenging doses was 18.5 or 24 h, only the lower conditioning dose appeared effective in inducing the radioadaptive response.
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Affiliation(s)
- Z Farooqi
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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95
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Wazer DE, Joyce M, Jung L, Band V. Alterations in growth phenotype and radiosensitivity after fractionated irradiation of breast carcinoma cells from a single patient. Int J Radiat Oncol Biol Phys 1993; 26:81-8. [PMID: 8482634 DOI: 10.1016/0360-3016(93)90176-v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PURPOSE To investigate growth regulation and radiosensitivity in surviving clonogens after fractionated irradiation. METHODS AND MATERIALS Four breast carcinoma cell lines isolated from the primary tumor (21NT, 21PT) and metastases (21MT-1, 21MT-2) of a single patient were exposed to cumulative radiation doses of 30 Gy yielding cell lines designated-IR with respect to their parent. The irradiated lines were then compared to their parent for serum-and growth factor-requirements under defined media conditions, ability to proliferate in soft agar, concentration of TGF-alpha in conditioned medium, and radiosensitivity. RESULTS The irradiated lines showed no change in proliferative doubling times under serum- and growth factor-supplemented media conditions. A single line, 21MT-1-IR, acquired a limited ability to proliferate in serum-and growth factor-deplete medium with a day 2-4 doubling time of 44.5 hr. Three lines, 21MT-1-IR, 21MT-2-IR, and 21NT-IR, formed colonies in soft agar in contrast to none of the unirradiated parent lines. There were significant 6-8 fold increases in conditioned media TGF-alpha concentrations for 21MT-2-IR and 21NT-IR cells. The 21MT-1-IR and 21NT-IR cells were significantly less radiosensitive than their respective parent lines. This decrease in radiosensitivity appeared to be at least partially mediated by a released factor as the radiosensitivity of 21MT-1 cells was significantly decreased by pre-incubation with conditioned medium from 21MT-1-IR cells. CONCLUSION Radiation-induced changes in growth phenotype vary with respect to clonal origin of the cell line and may influence the radiosensitivity of surviving clonogens after fractionated treatment.
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Affiliation(s)
- D E Wazer
- Department of Radiation Oncology, Tufts University School of Medicine, New England Medical Center, Boston, MA 02111
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96
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Powell SN, Abraham EH. The biology of radioresistance: similarities, differences and interactions with drug resistance. Cytotechnology 1993; 12:325-45. [PMID: 7764455 DOI: 10.1007/bf00744671] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Cells and tissues have developed a variety of ways of responding to a hostile environment, be it from drugs (toxins) or radiation (summarized in Fig. 1). Three categories of radiation damage limitation are: (i) DNA repair (ii) changes in cellular metabolism (iii) changes in cell interaction (cell contact or tissue-based resistance; whole organism based resistance). DNA repair has been evaluated predominantly by the study of repair-deficient mutants. The function of the repair genes they lack is not fully understood, but some of their important interactions are now characterized. For example, the interaction of transcription factors with nucleotide excision repair is made clear by the genetic syndromes of xeroderma-pigmentosum groups B, D and G. These diseases demonstrate ultraviolet light sensitivity and general impairment of transcription: they are linked by impaired unwinding of the DNA required for both transcription and repair. The transfer of DNA into cells is sometimes accompanied by a change in sensitivity to radiation, and this is of special interest when this is the same genetic change seen in tumors. DNA repair has a close relationship with the cell cycle and cell cycle arrest in response to damage may determine sensitivity to that damage. DNA repair mechanisms in response to a variety of drugs and types of radiation can be difficult to study because of the inability to target the damage to defined sequences in vivo and the lack of a satisfactory substrate for in vitro studies. Changes in cellular metabolism as a result of ionizing radiation can impart radiation resistance, which is usually transient in vitro, but may be more significant in vivo for tissues or tumors. The mechanisms by which damage is sensed by cells is unknown. The detection of free radicals is thought likely, but distortion to DNA structure or strand breakage and a direct effect on membranes are other possibilities for which there is evidence. Changes in extracellular ATP occur in response to damage, and this could be a direct membrane effect. External purinergic receptors can then be involved in signal transduction pathways resulting in altered levels of thiol protection or triggering apoptosis. Changes in the functional level of proteins as a consequence of ionizing radiation include transcription factors, for example c-jun and c-fos; cell cycle arrest proteins such as GADD (growth arrest and DNA damage inducible proteins) and p53; growth factors such as FGF, PDGF; and other proteins leading to radioresistance.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- S N Powell
- Department of Radiation Oncology, Massachusetts General Hospital, Boston 02114
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97
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Affiliation(s)
- U Kasid
- Department of Radiation Medicine, Georgetown University, Washington, D.C. 20007
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98
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Akashi M, Hachiya M, Koeffler HP, Suzuki G. Irradiation increases levels of GM-CSF through RNA stabilization which requires an AU-rich region in cancer cells. Biochem Biophys Res Commun 1992; 189:986-93. [PMID: 1472071 DOI: 10.1016/0006-291x(92)92301-d] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Granulocyte/macrophage colony stimulating factor (GM-CSF) is a hematopoietic growth factor that stimulates a wide range of myeloid hematopoietic cells; RNAs coding for many oncogenes and cytokines including GM-CSF have a very short half-life. The motif of AUUUA is a highly conserved sequence in the 3'untranslated regions (3'UTR) of these transcripts and is repeated a number of times in these short-lived cytokines and oncogenes. These sequences play a major role in controlling stability of these transcripts. Human cancer cells were transfected with a chimeric rabbit beta-globin gene linked to either a 58 bp sequence of the AT-rich region from GM-CSF or a control sequence. We have found that irradiation stimulates accumulation of GM-CSF, interleukin-6 (IL-6), and IL-1 beta RNAs. In addition, this accumulation of GM-CSF was at least, in part, a result of increased stabilization of GM-CSF transcripts. Further experiments showed that irradiation increased levels of the chimeric beta-globin transcripts containing AUUUA sequences from GM-CSF, but not those containing the control sequences. Our results suggest that irradiation increases expression of GM-CSF RNA and that posttranscriptional stabilization requiring AUUUA sequences probably is in part one of the mechanisms producing the increased levels of GM-CSF RNA by irradiation.
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Affiliation(s)
- M Akashi
- Division of Radiation Health, National Institute of Radiological Sciences, Chiba, Japan
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99
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Pelton BK, Hylton W, Denman AM. Activation of IL-6 production by UV irradiation of blood mononuclear cells from patients with systemic lupus erythematosus. Clin Exp Immunol 1992; 89:251-4. [PMID: 1638768 PMCID: PMC1554444 DOI: 10.1111/j.1365-2249.1992.tb06940.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cultured mononuclear cells from patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and normal donors were assayed for their ability to secrete IL-6 both spontaneously and after exposure to UV light. Mononuclear cells from SLE, RA and atopic control patients produced IL-6 spontaneously, while those from normal donors did not. Spontaneous production of IL-6 occurred in the non-adherent cell population. UV light-induced IL-6 production was confined exclusively to the SLE patients and was present only in the macrophage/monocyte fraction. This stimulation was induced by wavelengths in the UVA, UVB but not the UVC portion of the spectrum. These results suggest that cytokine release may be involved in the exacerbations of SLE provoked by photosensitivity.
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Affiliation(s)
- B K Pelton
- Division of Immunological Medicine, Northwick Park Hospital, Harrow, Middlesex, UK
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100
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Fuks Z, Weichselbaum RR. Radiation tolerance and the new biology: growth factor involvement in radiation injury to the lung. Int J Radiat Oncol Biol Phys 1992; 24:183-4. [PMID: 1512157 DOI: 10.1016/0360-3016(92)91041-k] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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