Cell inactivation by combined low dose-rate irradiation and intermittent hypoxia. (April 2015)

• Record Type: Journal Article
• Authors: Edin, Nina Jeppesen; Christoffersen, Stine; Fenne, Siri; Sandvik, Joe Alexander; Pettersen, Erik Olai
• Is Part Of: International journal of radiation biology. Volume 91:Number 4(2015:Apr.)
• Page Start: 336
• Page End: 345
• Publication Date: 2015-04
• Subjects: T-47D cells -- low dose-rate irradiation -- β-irradiation -- hypoxia; Radiation -- Physiological effect -- Periodicals; Radiobiology -- Periodicals; 571.45
• DOI: 10.3109/09553002.2014.996262
• Languages: English
• ISSNs: 0955-3002

Abstract

Abstract: Purpose : To investigate in detail the earlier observed combined effect of low dose-rate β-irradiation delivered at a dose-rate of 15 mGy/h and continued intermittent hypoxia that leads to extensive cell death after approximately 3–6 weeks. Material and methods : Continuous low dose-rate β-irradiation at a dose rate of 15, 1.5 or 0.6 mGy/h was given by incorporation of [ 3 H]-labelled valine into cellular protein. The cells were cultivated in an atmosphere with 4% O2 using an INVIVO2 hypoxia glove box. Clonogenic capacity, cell-cycle distribution and cellular respiration were monitored throughout the experiments. Results : After 3–6 weeks most cells died in response to the combined treatment, giving a surviving fraction of only 1–2%. However, on continued cultivation a few cells survived and restarted proliferation as the cellular oxygen supply increased with the reduced cell number. Irradiating the T-47D cells grown in an atmosphere with 4% O2 at dose-rates 10 and 25 times lower than 15 mGy/h did not have a pronounced effect on the clonogenic capacity with surviving fractions of 60–80%. Conclusions : Treatment of T-47D cells with low dose-rate β-irradiation leads to a specific effect on intermittent hypoxic cells, inactivating more than 98% of the cells in the population. Given improved oxygen conditions, the few surviving cells can restart their proliferation.