Logo image
Alterations in heat-induced radiosensitization accompanied by nuclear structure alterations in Chinese hamster cells
Journal article   Peer reviewed

Alterations in heat-induced radiosensitization accompanied by nuclear structure alterations in Chinese hamster cells

Andrei Laszlo, Teri Davidson, Amanda Harvey, Julia E Sim, Robert S Malyapa, Douglas R Spitz and Joseph L Roti Roti
International journal of hyperthermia, Vol.22(1), pp.43-60
02/2006
DOI: 10.1080/02656730500394296
PMID: 16423752

View Online

Abstract

This paper examined heat-induced radiosensitization in two Chinese hamster heat-resistant cell lines, HR-1 and OC-14, that were isolated from the same wild-type HA-1 cell line. It found a reduction of the magnitude of heat-induced radiosensitization after exposure to 43 degrees C in both HR-1 and OC-14 cells and a similar reduction after exposure to 45 degrees C in HR-1 cells, but not in OC-14 cells. The effect of heat exposure on a class of ionizing radiation-induced DNA damage that inhibits the ability of nuclear DNA to undergo super-coiling changes was also studied using the fluorescent halo assay in these three cell lines. Wild type cells exposed to either 43 or 45 degrees C before irradiation had a DNA rewinding ability that was intermediate between control and unheated cells, a phenomenon previously described as a masking effect. This masking effect was significantly reduced in HR-1 cells exposed to either 43 or 45 degrees C or in OC-14 cells exposed to 43 degrees C under conditions that heat-induced radiosensitization was reduced. In contrast, the masking effect was not altered in OC-14 cells exposed to 45 degrees C, conditions under which heat-induced radiosensitization was similar to that observed in wild-type HA-1 cells. These results suggest that a reduction in the masking effect is associated with a reduction of the magnitude of heat-induced radiosensitization in the HR-1 and OC-14 heat-resistant cell lines. The reduction of the masking effect in the cell lines resistant to heat-induced radiosensitization was associated with neither a reduction in the magnitude of the heat-induced increase in total nuclear protein content nor major differences in the protein profiles of the nucleoids isolated from heated cells.
Animals Cell Line Cricetinae Cricetulus DNA Damage Hyperthermia, Induced Nuclear Proteins - biosynthesis Radiation Tolerance

Details

Metrics

Logo image