Title: Assessment of γH2AX nuclear foci number and size in normal and repair-deficient cells irradiated with low and high linear energy transfer radiation

Authors: C. Bracalente, I.L. Ibanez, B. Molinari, M.A. Palmieri, A. Maglioco, L. Policastro, A.J. Kreiner, A. Burlon, A. Valda, J. Davidson, M. Davidson, M. Vazquez, M. Ozafran, H. Duran

Addresses: Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina. ' Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Avda. Rivadavia 1917, CP C1033AAJ, Cdad. de Buenos Aires, Argentina. ' Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Avda. Rivadavia 1917, CP C1033AAJ, Cdad. de Buenos Aires, Argentina. ' Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina. ' Consejo Nacional de Investigaciones Cientificas y Tecnicas, Avda. Rivadavia 1917, CP C1033AAJ, Cdad. de Buenos Aires, Argentina. ' Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Avda. Rivadavia 1917, CP C1033AAJ, Cdad. de Buenos Aires, Argentina. ' Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Avda. Rivadavia 1917, CP C1033AAJ, Cdad. de Buenos Aires, Argentina. ' Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina; Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, Argentina. ' Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin, Argentina. ' Consejo Nacional de Investigaciones Cientificas y Tecnicas, Avda. Rivadavia 1917, CP C1033AAJ, Cdad. de Buenos Aires, Argentina. ' Consejo Nacional de Investigaciones Cientificas y Tecnicas, Avda. Rivadavia 1917, CP C1033AAJ, Cdad. de Buenos Aires, Argentina. ' Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina. ' Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina. ' Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, (1650) San Martin, Argentina; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Avda. Rivadavia 1917, CP C1033AAJ, Cdad. de Buenos Aires, Argentina

Abstract: The aim of this study was to evaluate the DNA damage induced by low and high linear energy transfer radiation in two related cell lines with different radiation sensitivity, CHO10B2 and irs-20 cells (defective in DNA-PKcs). Double-strand breaks were assessed by the detection of phosphorylated histone H2AX foci (γH2AX). The number of foci increased as a function of dose for both cell lines and types of radiation. However, irs-20 cells showed a higher number of foci than the parental CHO10B2. An increase in the foci size was observed for both cell lines after lithium irradiation. This could be attributed to clusters of DNA damage. Moreover, the number of lithium-induced larger foci per nuclei increased with dose and fitted with the expected number of hits per nucleus. Concluding, γH2AX foci size provides a potential tool to characterise the intrinsic radiosensitivity of cells related to DNA damage and to compare the effects of different quality radiations.

Keywords: ionising radiation; LET; linear energy transfer; DNA double strand breaks; gamma H2AX; H2AX foci size; DNA-PKcs; CHO10B2; irs-20; low radiation; DNA damage; radiation sensitivity; lithium irradiation; cell radiosensitivity.

DOI: 10.1504/IJLR.2010.036968

International Journal of Low Radiation, 2010 Vol.7 No.5, pp.393 - 408

Available online: 18 Nov 2010 *

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