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PubMed · 10993634

Hyperfast, early cell response to ionizing radiation.

V Ponette·C Le Péchoux·E Deniaud-Alexandre·M Fernet·N Giocanti·H Tourbez·V Favaudon
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Abstract

PURPOSE: To determine whether the oscillatory changes of radio-sensitivity which occur within fractions of a second to a few minutes following flash irradiation correlate with an altered incidence of apoptosis, DNA strand breaks or lipid-coupled signalling. MATERIALS AND METHODS: Human tumor cells (SQ-20B, LoVo) or Chinese hamster V79 fibroblasts were exposed to split-dose, pulse irradiation with 3.5 MeV electrons at high dose-rate (12 or 120 Gy x s(-1)) and the effects assessed by clonogenic assays, analysis of DNA cleavage and microscopic observation. RESULTS: The processes underlying oscillatory radiation response were saturable, but did not correlate with an increased incidence of DNA single- or double-strand breaks or apoptosis. N-acetylcysteine and inhibitors of lipid-derived signalling also failed to alter oscillatory response. However, this response did correlate with phenotypic alterations evoking mitotic or delayed cell death. Furthermore, high dose-rate irradiation provided a lower level of instability than protracted gamma-ray irradiation. CONCLUSIONS: It is proposed that the early steps of DNA damage recognition and repair following priming radiation exposure bring about rapid, synchronous remodeling of chromatin, evoking enhanced chromosome damage upon re-irradiation.

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AnimalsApoptosisCell LineCell SeparationCricetinaeDNADNA DamageDNA FragmentationDose-Response Relationship, RadiationFibroblastsFlow CytometryGamma RaysHumansIn Situ Nick-End LabelingLipid MetabolismMitosisOxidative StressSignal TransductionTime FactorsTumor Cells, CulturedJournal ArticleResearch Support, Non-U.S. Gov't

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V Ponette, C Le Péchoux, E Deniaud-Alexandre, M Fernet, N Giocanti, H Tourbez, V Favaudon. 2000. Hyperfast, early cell response to ionizing radiation.. https://doi.org/10.1080/09553000050134465

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