Identification of distinct and common gene expression changes after oxidative stress and gamma and ultraviolet radiation.
The human genome is exposed to many different kinds of DNA-damaging agents. While most damage is detected and repaired through complex damage recognition and repair machineries, some damage has the potential to escape these mechanisms. Unrepaired DNA damage can give rise to alterations and mutations in the genome in an individual cell, which can result in malignant transformation, especially when critical genes are deregulated. In this study, we investigated gene expression changes in response to oxidative stress, gamma (gamma) radiation, and ultraviolet (UV) radiation and their potential implications in cancer development. Doses were selected for each of the three treatments, based on their ability to cause a similar G(1) checkpoint induction and slow down in early S-phase progression, as reflected by a comparable reduction in cyclin E-associated kinase activity of at least 75% in logarithmically growing human dermal diploid fibroblasts. To investigate gene expression changes, logarithmically growing dermal diploid fibroblasts were exposed to either gamma radiation (5 Gy), oxidative stress (75 microM of tert-butyl hydroperoxide (t-butyl-OOH)), or UV radiation (UVC) (7.5 J/m(2)) and RNA was harvested 6 h after treatment. Gene expression was analyzed using the NIEHS Human ToxChip 2.0 with approximately 1901 cDNA clones representing known genes and expressed sequence tags (ESTs). We were able to identify common and distinct responses in dermal diploid fibroblasts to the three different stimuli used. Within our analysis, gene expression profiles in response to gamma radiation and oxidative stress appeared to be more similar than profiles expressed after UV radiation. Interestingly, equivalent cyclin E-associated kinase activity reduction with all the three treatments was associated with greater transcriptional changes after UV radiation than after gamma radiation and oxidative stress. While samples treated with UV radiation displayed modulations of their mitogen activated protein kinase (MAPK) pathway, gamma radiation had its major influence on cell-cycle progression in S-phase and mitosis. In addition, cell cultures from different individuals displayed significant differences in their gene expression responses to DNA damage.
Heinloth
Alexandra N
AN
Growth Control and Cancer Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
Shackelford
Rodney E
RE
Innes
Cynthia L
CL
Bennett
Lee
L
Li
Leping
L
Amin
Rupesh P
RP
Sieber
Stella O
SO
Flores
Kristina G
KG
Bushel
Pierre R
PR
Paules
Richard S
RS
D000328:Adult; D002478:Cells, Cultured; D016000:Cluster Analysis; D019927:Cyclin E; D018844:Cyclin-Dependent Kinases / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D004249:DNA Damage / Q000235:genetics; D004307:Dose-Response Relationship, Radiation; D004789:Enzyme Activation / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000528:radiation effects*; D016193:G1 Phase / Q000187:drug effects / Q000528:radiation effects; D005720:Gamma Rays / Q000009:adverse effects*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects*; D014644:Genetic Variation; D006801:Humans; D020935:MAP Kinase Signaling System / Q000528:radiation effects; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D018384:Oxidative Stress; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D016196:S Phase / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
D019927:Cyclin E; D020122:tert-Butylhydroperoxide; D018844:Cyclin-Dependent Kinases