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Radiosensitivity of human tumour cells is correlated with the induction but not with the repair of DNA double-strand breaks.

El-Awady RA, Dikomey E, Dahm-Daphi J - Br. J. Cancer (2003)

Bottom Line: In contrast, normal fibroblasts raised from skin biopsies of seven individuals showed only a marginal variation with 18-20 dsb/Gy/diploid DNA content.This residual damage was found to be influenced not only by the actual number of residual dsb, but also by apoptosis and cell cycle progression which had impact on CFGE measurements.Some cell line strains were able to proliferate even after exposure to 150 Gy while others were found to degrade their DNA.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy and Radiation Oncology, University Hospital of Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.

ABSTRACT
Nine human tumour cell lines (four mammary, one bladder, two prostate, one cervical, and one squamous cell carcinoma) were studied as to whether cellular radiosensitivity is related to the number of initial or residual double-strand breaks (dsb). Cellular sensitivity was measured by colony assay and dsb by means of constant- and graded-field gel electrophoresis (CFGE and GFGE, respectively). The nine tumour cell lines showed a broad variation in cellular sensitivity (SF2 0.17-0.63). The number of initial dsb as measured by GFGE ranged between 14 and 27 dsb/Gy/diploid DNA content. In contrast, normal fibroblasts raised from skin biopsies of seven individuals showed only a marginal variation with 18-20 dsb/Gy/diploid DNA content. For eight of the nine tumour cell lines, there was a significant correlation between the number of initial dsb and the cellular radiosensitivity. The tumour cells showed a broad variation in the amount of dsb measured 24 h after irradiation by CFGE, which, however, was not correlated with the cellular sensitivity. This residual damage was found to be influenced not only by the actual number of residual dsb, but also by apoptosis and cell cycle progression which had impact on CFGE measurements. Some cell line strains were able to proliferate even after exposure to 150 Gy while others were found to degrade their DNA. Our results suggest that for tumour cells, in contrast to normal cells, the variation in sensitivity is mainly determined by differences in the initial number of dsb induced.

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Relationship between dsb and cellular radiosensitivity. (A) Number of dsb induced per Gy and per Da (as calculated from Figure 4) and (B) number of dsb measured 24 h after 150 Gy (taken from Figure 5B) were plotted vs cellular radiosensitivity expressed as Dbar (from Table 1).
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fig7: Relationship between dsb and cellular radiosensitivity. (A) Number of dsb induced per Gy and per Da (as calculated from Figure 4) and (B) number of dsb measured 24 h after 150 Gy (taken from Figure 5B) were plotted vs cellular radiosensitivity expressed as Dbar (from Table 1).

Mentions: Figure 7Figure 7


Radiosensitivity of human tumour cells is correlated with the induction but not with the repair of DNA double-strand breaks.

El-Awady RA, Dikomey E, Dahm-Daphi J - Br. J. Cancer (2003)

Relationship between dsb and cellular radiosensitivity. (A) Number of dsb induced per Gy and per Da (as calculated from Figure 4) and (B) number of dsb measured 24 h after 150 Gy (taken from Figure 5B) were plotted vs cellular radiosensitivity expressed as Dbar (from Table 1).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2394378&req=5

fig7: Relationship between dsb and cellular radiosensitivity. (A) Number of dsb induced per Gy and per Da (as calculated from Figure 4) and (B) number of dsb measured 24 h after 150 Gy (taken from Figure 5B) were plotted vs cellular radiosensitivity expressed as Dbar (from Table 1).
Mentions: Figure 7Figure 7

Bottom Line: In contrast, normal fibroblasts raised from skin biopsies of seven individuals showed only a marginal variation with 18-20 dsb/Gy/diploid DNA content.This residual damage was found to be influenced not only by the actual number of residual dsb, but also by apoptosis and cell cycle progression which had impact on CFGE measurements.Some cell line strains were able to proliferate even after exposure to 150 Gy while others were found to degrade their DNA.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy and Radiation Oncology, University Hospital of Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany.

ABSTRACT
Nine human tumour cell lines (four mammary, one bladder, two prostate, one cervical, and one squamous cell carcinoma) were studied as to whether cellular radiosensitivity is related to the number of initial or residual double-strand breaks (dsb). Cellular sensitivity was measured by colony assay and dsb by means of constant- and graded-field gel electrophoresis (CFGE and GFGE, respectively). The nine tumour cell lines showed a broad variation in cellular sensitivity (SF2 0.17-0.63). The number of initial dsb as measured by GFGE ranged between 14 and 27 dsb/Gy/diploid DNA content. In contrast, normal fibroblasts raised from skin biopsies of seven individuals showed only a marginal variation with 18-20 dsb/Gy/diploid DNA content. For eight of the nine tumour cell lines, there was a significant correlation between the number of initial dsb and the cellular radiosensitivity. The tumour cells showed a broad variation in the amount of dsb measured 24 h after irradiation by CFGE, which, however, was not correlated with the cellular sensitivity. This residual damage was found to be influenced not only by the actual number of residual dsb, but also by apoptosis and cell cycle progression which had impact on CFGE measurements. Some cell line strains were able to proliferate even after exposure to 150 Gy while others were found to degrade their DNA. Our results suggest that for tumour cells, in contrast to normal cells, the variation in sensitivity is mainly determined by differences in the initial number of dsb induced.

Show MeSH
Related in: MedlinePlus