Cell inactivation by combined low dose-rate irradiation and intermittent hypoxia.

Autor: Edin NJ; Department of Physics, University of Oslo , 0316 Oslo , Norway., Christoffersen S, Fenne S, Sandvik JA, Pettersen EO
Jazyk: angličtina
Zdroj: International journal of radiation biology [Int J Radiat Biol] 2015 Apr; Vol. 91 (4), pp. 336-45. Date of Electronic Publication: 2015 Jan 30.
DOI: 10.3109/09553002.2014.996262
Abstrakt: 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.
Databáze: MEDLINE
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