| Radiation-induced up-regulation of telomerase in KG1a cells is influenced by dose-rate and radiation quality. | |
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MedLine Citation:
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PMID: 12556344 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: To examine the influence of dose, dose-rate and radiation quality on telomerase activity (TA) in the KG1a hematopoietic cell line. MATERIALS AND METHODS: KG1a cells were irradiated with gamma-rays (0.5-5 Gy) at 0.025 Gy/min, 0.30 Gy/min and 1.57 Gy/min and with a neutron/gamma-ray field (5 Gy). Cell viability was determined by trypan blue exclusion. Apoptosis and cell cycle distribution were evaluated by flow cytometry. Proliferative capacity was studied by MTS assay and TA by PCR. Following 3Gy gamma-irradiation, the expression of hTERT, hTR and TP1 genes was evaluated by RT-PCR. RESULTS: Dose- and dose-rate-dependent telomerase activation with an increase in hTERT mRNA and a drop in hTP1 mRNA were observed after irradiation. Down-regulation of telomerase activity occurred in a dose-dependent manner. Although non-significant changes in short-term survival were observed after irradiation, late apoptosis became evident after G2/M arrest. Early repression of TA preceded telomerase activation in samples irradiated with a neutron/gamma-ray field, in which short-term survival was affected. CONCLUSIONS: Radiation-induced telomerase activation depends on dose-rate. High-LET and low-LET irradiations induce similar changes in TA that differ mainly in their kinetics and their magnitude. Changes in TA are not related to cell-cycle redistribution nor to the induction of cell death; they are the consequence of specific regulatory responses to ionizing radiation. Mechanisms including both transcriptional and post-translational control may be involved in this regulation. |
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Authors:
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M del Rosario Pérez; D Dubner; S Michelin; F Leteurtre; E D Carosella; P A Gisone |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: International journal of radiation biology Volume: 78 ISSN: 0955-3002 ISO Abbreviation: Int. J. Radiat. Biol. Publication Date: 2002 Dec |
Date Detail:
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Created Date: 2003-01-30 Completed Date: 2003-02-21 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8809243 Medline TA: Int J Radiat Biol Country: England |
Other Details:
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Languages: eng Pagination: 1175-83 Citation Subset: IM; S |
Affiliation:
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Autoridad Regulatoria Nuclear, Gerencia de Apoyo Científico, Laboratorio de Radiopatología, Av del Libertador 8250, CP 1429 Buenos Aires, Argentina. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Apoptosis Cell Cycle / radiation effects Cell Survival Dose-Response Relationship, Radiation Down-Regulation Humans Kinetics Protein Biosynthesis RNA, Messenger / metabolism, radiation effects* Telomerase / biosynthesis*, metabolism Time Factors Transcription, Genetic Up-Regulation* |
| Chemical | |
Reg. No./Substance:
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0/RNA, Messenger; EC 2.7.7.49/Telomerase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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