Comet fluorescence in situ hybridization analysis for oxidative stress-induced DNA damage in colon cancer relevant genes.
Our objective was to study whether products of oxidative stress, such as hydrogen peroxide (H(2)O(2)), trans-2-hexenal, and 4-hydroxy-2-nonenal (HNE), cause DNA damage in genes, relevant for human colon cancer. For this, total DNA damage was measured in primary human colon cells and colon adenoma cells (LT97) using the single-cell gel electrophoresis assay, known as "Comet Assay." APC, KRAS, and TP53 were marked in the comet images using fluorescence in situ hybridization (Comet FISH). The migration of APC, KRAS, or TP53 signals into the comet tails was quantified and compared to total DNA damage. All three substances were clearly genotoxic for APC, KRAS, and TP53 genes and total DNA in both types of cells. In primary colon cells, TP53 gene was more sensitive toward H(2)O(2), trans-2-hexenal, and HNE than total DNA was. In LT97 cells, the TP53 gene was more sensitive only toward trans-2-hexenal and HNE. APC and KRAS genes were more susceptible than total DNA to both lipid peroxidation products but only in primary colon cells. This suggests genotoxic effects of lipid peroxidation products in APC, KRAS, and TP53 genes. In LT97 cells, TP53 was more susceptible than APC and KRAS toward HNE. Based on the reported gatekeeper properties of TP53, which in colon adenoma is frequently altered to yield carcinoma, this implies that HNE is likely to contribute to cancer progression. This new experimental approach facilitates studies on effects of nutrition-related carcinogens in relevant target genes.
Glei
Michael
M
Institute for Nutrition, Dornburger Strasse 25, Friedrich-Schiller-University Jena, 07743 Jena, Germany.
Schaeferhenrich
Anja
A
Claussen
Uwe
U
Kuechler
Alma
A
Liehr
Thomas
T
Weise
Anja
A
Marian
Brigitte
B
Sendt
Wolfgang
W
Pool-Zobel
Beatrice L
BL
D025601:Adenomatous Polyposis Coli Protein / Q000235:genetics; D000368:Aged; D000447:Aldehydes / Q000494:pharmacology; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D003106:Colon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D003110:Colonic Neoplasms / Q000235:genetics / Q000473:pathology; D020552:Comet Assay / Q000379:methods*; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics; D018631:ras Proteins / Q000235:genetics
D025601:Adenomatous Polyposis Coli Protein; D000447:Aldehydes; D016159:Tumor Suppressor Protein p53; C051750:2-hexenal; D006861:Hydrogen Peroxide; D018631:ras Proteins; C027576:4-hydroxy-2-nonenal