Human adenoma cells are highly susceptible to the genotoxic action of 4-hydroxy-2-nonenal.
Oxidative stress and resulting lipid peroxidation are important risk factors for dietary-associated colon cancer. To get a better understanding of the underlying molecular mechanisms, we need to characterise the risk potential of the key compounds, which cause DNA damage in cancer-relevant genes and especially in human target cells. Here, we investigated the genotoxic effects of 4-hydroxy-2-nonenal (HNE) and hydrogen peroxide (H(2)O(2)) in human colon cells (LT97). LT97 is a recently established cell line from a differentiated microadenoma and represents cells from frequent preneoplastic lesions of the colon. The genomic characterisation of LT97 was performed with 24-colour FISH. Genotoxicity was determined with single cell microgelelectrophoresis (Comet assay). Comet FISH was used to study the sensitivity of TP53-a crucial target gene for the transition of adenoma to carcinoma-towards HNE. Expression of glutathione S-transferases (GST), which deactivates HNE, was determined as GST activity and GSTP1 protein levels. LT97 cells were compared to primary human colon cells and to a differentiated clone of HT29. Karyotyping revealed that the LT97 cell line had a stable karyotype with only two clones, each containing a translocation t(7;17) and one aberrant chromosome 1. The Comet assay experiments showed that both HNE and H(2)O(2) were clearly genotoxic in the different human colon cells. HNE was more genotoxic in LT97 than in HT29clone19A and primary human colon cells. After HNE incubation, TP53 migrated more efficiently into the comet tail than the global DNA, which suggests a higher susceptibility of the TP53 gene to HNE. GST expression was significantly lower in LT97 than in HT29clone19A cells, which could explain the higher genotoxicity of HNE in the colon adenoma cells. In conclusion, the LT97 is a relevant model for studying genotoxicity of colon cancer risk factors since colon adenoma are common preneoplastic lesions occurring in advanced age.
Schaeferhenrich
Anja
A
Department of Nutritional Toxicology, Institute for Nutrition, Friedrich Schiller University Jena, Dornburger Strasse 25, Germany.
Beyer-Sehlmeyer
Gabriele
G
Festag
Grit
G
Kuechler
Alma
A
Haag
Natja
N
Weise
Anja
A
Liehr
Thomas
T
Claussen
Uwe
U
Marian
Brigitte
B
Sendt
Wolfgang
W
Scheele
Johannes
J
Pool-Zobel
Beatrice Louise
BL
D000236:Adenoma / Q000235:genetics* / Q000378:metabolism; D000447:Aldehydes / Q000633:toxicity*; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D004273:DNA, Neoplasm / Q000187:drug effects*; D005260:Female; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006131:Growth Inhibitors / Q000633:toxicity*; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D000447:Aldehydes; D004273:DNA, Neoplasm; D006131:Growth Inhibitors; D016159:Tumor Suppressor Protein p53; D006861:Hydrogen Peroxide; D005982:Glutathione Transferase; D005978:Glutathione; C027576:4-hydroxy-2-nonenal