Differential response induced by exposure to low-dose ionizing radiation in SHSY-5Y and normal human fibroblast cells.
Radiation therapy has been used in the treatment of a wide variety of cancers for nearly a century and is one of the most effective ways to treat cancer. Low-dose ionizing radiation (IR) can interfere with cell division of cancer and normal cells by introducing oxidative stress and injury to DNA. The differences in the response to IR-induced DNA damage and increased reactive oxygen species between normal human fibroblasts (NHFs) and cancerous SHSY-5Y cells were considered. H2AX staining and comet assays revealed that NHF cells responded by initiating a DNA repair sequence whereas SHSY-5Y cells did not. In addition, NHF cells appeared to quench the oxidative stress induced by IR, and after 24 h no DNA damage was present. SHSY-5Y cells, however, did not repair their DNA, did not quench the oxidative stress, and showed characteristic signs that they were beginning to undergo apoptosis. These results indicate that there is a differential response between this cancerous and normal cell line in their ability to respond to low-dose IR, and these differences need to be exploited in order to treat cancer effectively. Further study is needed in order to elucidate the mechanism by which SHSY-5Y cells undergo apoptosis following radiation and why these normal cells are better equipped to deal with IR-induced double-strand breaks and oxidative stress.
McLachlan-Burgess
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Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, Canada N9B 3P4.
McCarthy
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Griffin
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Richer
J
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Cutler
R G
RG
Pandey
S
S
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D017209:Apoptosis / Q000528:radiation effects*; D053148:Caspase 3 / Q000096:biosynthesis; D002467:Cell Nucleus / Q000528:radiation effects / Q000648:ultrastructure; D020552:Comet Assay; D004249:DNA Damage; D004260:DNA Repair; D005347:Fibroblasts / Q000528:radiation effects* / Q000648:ultrastructure; D006657:Histones / Q000032:analysis; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000528:radiation effects; D009447:Neuroblastoma; D046988:Proteasome Endopeptidase Complex / Q000096:biosynthesis; D011839:Radiation, Ionizing; D017382:Reactive Oxygen Species / Q000032:analysis; D013194:Staining and Labeling; D014343:Trypan Blue; D014407:Tumor Cells, Cultured
C468783:H2AX protein, human; D006657:Histones; D017382:Reactive Oxygen Species; D000255:Adenosine Triphosphate; D053148:Caspase 3; D046988:Proteasome Endopeptidase Complex; D014343:Trypan Blue