The role of intracellular calcium in the cellular response to ionizing radiation

D. E. Hallahan, D. Bleakman, S. Virudachalam, D. Lee, D. Grdina, D. W. Kufe, R. R. Weichselbaum

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Calcium is required as a cofactor by primer recognition proteins involved in DNA synthesis and by protein kinase C (PKC), which is activated by ionizing radiation. Because these processes may be involved in radiation- mediated regulation of the progression of cells through the phases of the cell cycle, we studied the effects of the intracellular Ca2+ chelator, acetoxymethyl-1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (AM- BAPTA), on PKC activation, expression of c-jun and Gadd45 and distribution of cells in the phases of the cell cycle after irradiation. AM-BAPTA prevented ionizing-radiation-induced activation of PKC and expression of c-jun in cells of human tumor cell lines. Conversely, calcium chelation had no effect on X- ray-induced expression of the Gadd45 gene. To determine whether changes in the intracellular Ca2+ concentration ([Ca2+](i)) occurred during irradiation, we measured [Ca2+](i) in single cells using fura-2-based microfluorimetry. There was no increase in [Ca2+](i) during or after irradiation of cells of the human tumor cell lines RIT-3, SQ-20B or HL-60 or normal human fibroblast strain IMR-90. The percentage of human tumor cells crossing the G1/S-phase border was reduced by pretreatment with AM-BAPTA. These data indicate that calcium is required for ionizing radiation-induced cell cycle regulation and PKC activation, but that increases in [Ca2+](i) do not occur in cells of the cell lines irradiated in this study.

Original languageEnglish
Pages (from-to)392-400
Number of pages9
JournalRadiation research
Volume138
Issue number3
DOIs
StatePublished - 1994

Fingerprint

Dive into the research topics of 'The role of intracellular calcium in the cellular response to ionizing radiation'. Together they form a unique fingerprint.

Cite this