In vitro response of human dermal fibroblasts to X-irradiation: relationship between radiation-induced clonogenic cell death, chromosome aberrations and markers of proliferative senescence or differentiation
M. Rave-frank et al., In vitro response of human dermal fibroblasts to X-irradiation: relationship between radiation-induced clonogenic cell death, chromosome aberrations and markers of proliferative senescence or differentiation, INT J RAD B, 77(12), 2001, pp. 1163-1174
Purpose : To analyse the relationship between radiation-induced clonogenic
cell death, chromosome aberrations and markers of proliferative senescence
or differentiation.
Materials and methods : Plateau-phase human dermal fibroblasts from 18 dono
rs were irradiated with graded doses of 1-6 Gy 200 kV X-rays. Cell survival
was determined by a colony-forming assay. Markers of differentiation or se
nescence were: spontaneous and radiation-induced clonal differentiation, wh
ich was determined morphologically and by the cellular potential to prolife
rate in clonal culture, also single-cell beta -galactosidase (beta -gal) st
aining at pH 6.0; and the secretion of transforming growth factor-beta (TGF
-beta1) into the culture medium. Chromosome aberrations were determined as
genomic yields of dicentric chromosomes and the excess acentric fragments,
scored in Giemsa-stained metaphases, and as partial yields of reciprocal tr
anslocations for chromosomes 4, 7 and 9 using the FISH method.
Results: A broad spread was found in the shapes of the survival curves, wit
h SF2 ranging from 0.041 +/- 0.015 to 0.63 +/- 0.05. Radiation-induced clon
al differentiation as well as the secretion of TGF-beta1 was elevated in ra
diosensitive samples. With respect to chromosome aberrations, a significant
correlation was found between clonogenic survival and radiation-induced ex
cess acentric fragments.
Conclusions : In the fibroblast cell system, in vitro radiosensitivity is d
etermined not only by processes directly involved in DNA-damage recognition
and repair, but also by intracellular signalling cascades, which will lead
to differentiation processes.