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Oxidative DNA base damage and antioxidant enzyme activities in human lung cancer
P Jaruga1, T H Zastawny, J Skokowski
1Department of Clinical Biochemistry, Medical School, Bydgoszcz, Poland.
Abstract:
We have investigated levels of antioxidant enzymes and free radical-induced DNA base modifications in human cancerous lung tissues and in their cancer-free surrounding tissues. Various DNA base lesions in chromatin of lung tissues were measured by gas chromatography-mass spectrometry. Activities of superoxide dismutase, catalase and glutathione peroxidase were also measured in lung tissues. Higher levels of DNA lesions were observed in cancerous tissues than in cancer-free surrounding tissues. Antioxidant enzyme levels were lower in cancerous tissues. The results indicate an association between decreased activities of antioxidant enzymes and increased levels of DNA lesions in cancerous tissues. Higher levels of DNA lesions suggest that free radical reactions may be increased in malignant tumor cells.
Insights
Lung cancer tissues show higher DNA damage and lower antioxidant enzyme activity compared to healthy tissues. This suggests increased free radical activity contributes to malignant tumor development.
Area of Science:
- Biochemistry
- Oncology
- Molecular Biology
Background:
- Oxidative stress, caused by an imbalance between free radicals and antioxidants, is implicated in cancer development.
- Antioxidant enzymes play a crucial role in protecting cells from DNA damage induced by reactive oxygen species.
Purpose of the Study:
- To investigate the levels of antioxidant enzymes and DNA base modifications in human lung cancerous tissues versus surrounding cancer-free tissues.
- To explore the association between antioxidant enzyme activity and DNA damage in lung cancer.
Main Methods:
- Gas chromatography-mass spectrometry was used to measure various DNA base lesions in lung tissue chromatin.
- Enzyme activities of superoxide dismutase, catalase, and glutathione peroxidase were quantified in both cancerous and non-cancerous lung tissues.
Main Results:
- Human cancerous lung tissues exhibited significantly higher levels of DNA base lesions compared to adjacent cancer-free tissues.
- Activities of key antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase, were found to be lower in cancerous tissues.
- A negative correlation was observed between antioxidant enzyme activity and the extent of DNA base modifications in lung cancer tissues.
Conclusions:
- Decreased antioxidant enzyme activity in lung cancer tissues is associated with increased levels of free radical-induced DNA damage.
- Elevated DNA lesions in malignant tumor cells suggest a heightened role of free radical reactions in lung carcinogenesis.
- These findings highlight the potential involvement of oxidative stress pathways in the progression of lung cancer.