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Updated: Aug 13, 2026
Quantification of three DNA Lesions by Mass Spectrometry and Assessment of Their Levels in Tissues of Mice Exposed to Ambient Fine Particulate Matter
Published on: May 29, 2019
Endogenous lipid hydroperoxide-mediated DNA-adduct formation in min mice
Michelle V Williams1, Seon Hwa Lee, Michael Pollack
1Center for Cancer Pharmacology, University of Pennsylvania, 854 BRB II/III, 421 Curie Boulevard, Philadelphia, PA 19104-6160, USA.
Abstract:
Despite intensive research over the last two decades, there are still no specific markers of endogenous lipid hydroperoxide-mediated DNA damage. We recently demonstrated that heptanone-etheno-2'-deoxyguanosine adducts are formed in the DNA of rat intestinal epithelial cells that stably express cyclooxygenase-2. Heptanone-etheno adducts can only arise from the reaction of lipid hydroperoxide-derived 4-oxo-2(E)-nonenal with DNA. This raised the possibility that similar adducts would be formed in vivo in settings where cyclooxygenase-2 expression is increased. Therefore, DNA-adduct formation was studied in C57BL/6JAPC(min) mice, a colorectal cancer mouse model in which cyclooxygenase-2 is up-regulated. 15(S)-Hydroperoxy-5Z,8Z,11Z,13E-eicosatetraenoic acid is the major lipid hydroperoxide produced endogenously by cyclooxygenase-2. It undergoes homolytic decomposition to the DNA-reactive bifunctional electrophile 4-oxo-2(E)-nonenal, which forms heptanone-etheno adducts with DNA. A quantitative comparison was made of the heptanone-etheno-DNA adducts present in C57BL/6J and C57BL/6JAPC(min) mice. Using highly specific and sensitive methodology based on stable isotope dilution liquid chromatography/tandem mass spectrometry, we have detected the endogenous formation of heptanone-etheno adducts in mammalian tissue DNA for the first time. In addition, we found that there were statistically significant increased levels of the heptanone-etheno-2'-deoxyguanosine and heptanone-etheno-2'-deoxycytidine adducts in the C57BL/6JAPC(min) mice when compared with the control C57BL/6J mice.
Insights
Researchers identified specific DNA adducts, heptanone-etheno-2'-deoxyguanosine and heptanone-etheno-2'-deoxycytidine, formed by lipid hydroperoxides. These adducts were significantly increased in a colorectal cancer mouse model with elevated cyclooxygenase-2, marking a breakthrough in detecting lipid hydroperoxide-mediated DNA damage.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- Lipid hydroperoxides cause DNA damage, but specific markers are lacking.
- Cyclooxygenase-2 (COX-2) up-regulation is linked to increased lipid hydroperoxide production.
- Previous studies identified heptanone-etheno-2'-deoxyguanosine adducts in cell cultures with COX-2 expression.
Purpose of the Study:
- To investigate the in vivo formation of heptanone-etheno adducts in a colorectal cancer mouse model.
- To determine if cyclooxygenase-2 up-regulation leads to increased endogenous heptanone-etheno-DNA adducts.
- To establish specific markers for lipid hydroperoxide-mediated DNA damage.
Main Methods:
- Utilized C57BL/6JAPC(min) mice, a model for colorectal cancer with elevated COX-2.
- Employed stable isotope dilution liquid chromatography/tandem mass spectrometry for sensitive adduct detection.
- Quantitatively compared heptanone-etheno-DNA adduct levels between control and cancer model mice.
Main Results:
- Detected endogenous formation of heptanone-etheno adducts in mammalian tissue DNA for the first time.
- Found statistically significant increases in heptanone-etheno-2'-deoxyguanosine and heptanone-etheno-2'-deoxycytidine adducts in C57BL/6JAPC(min) mice compared to controls.
- Confirmed 4-oxo-2(E)-nonenal as the reactive electrophile derived from 15(S)-Hydroperoxy-5Z,8Z,11Z,13E-eicosatetraenoic acid.
Conclusions:
- Heptanone-etheno adducts serve as specific biomarkers for endogenous lipid hydroperoxide-mediated DNA damage.
- Elevated cyclooxygenase-2 expression in vivo promotes the formation of these DNA adducts.
- This research provides a crucial tool for understanding the role of lipid peroxidation in cancer development.
