Related Experiment Videos
Abnormal DNA repair in selenium-treated human cells
Khaled S Abul-Hassan1, Bruce E Lehnert, Lorraine Guant
1Basic Research Laboratory, National Cancer Institute, Building 37, Room 6144, NCI, National Institutes of Health, 37 Convent Dr MSC 4255, Bethesda, MD 20892-4255, USA. khaled_abul_hassan@hotmail.com
Mutation Research
|December 4, 2004
Summary
Selenium (Se) exposure inhibits DNA repair mechanisms. Studies show reduced resistivity to cisplatin and impaired transcription-coupled repair in Se-treated cells, indicating potential genotoxicity.
Area of Science:
- Biochemistry
- Genetics
- Toxicology
Background:
- Selenium (Se) acts as a micronutrient with dual roles, exhibiting genotoxic, antimutagenic, and anticarcinogenic properties based on concentration and oxidation state.
- Understanding Se's impact on DNA repair is crucial given its environmental and industrial relevance.
Purpose of the Study:
- To investigate the effect of low-dose sodium selenite on human osteosarcoma (U2OS) cells and primary lymphocytes.
- To assess Se's influence on cellular resistance to cisplatin and DNA repair pathways, including transcription-coupled repair (TCR) and double-strand break rejoining (DSBR).
Main Methods:
- Host Cell Reactivation (HCR) Assay to measure TCR capacity in Se-treated U2OS cells.
- Challenge assay to evaluate DSBR in Se-treated human primary lymphocytes.
- MTT assay for cytotoxicity assessment.
Main Results:
- U2OS cells showed reduced resistivity to cisplatin and significantly impaired TCR capacity after Se treatment, despite no significant cytotoxicity.
- Primary lymphocytes exhibited cytotoxicity only at 10 microM Se.
- A significant increase in dicentric chromosomes was observed in lymphocytes treated with 1 microM Se plus irradiation, suggesting compromised DNA repair.
Conclusions:
- Inorganic selenium (Se) directly inhibits cellular DNA repair capacity.
- Se exposure can reduce cellular resistance to genotoxic agents like cisplatin and impair critical DNA repair pathways, highlighting potential risks associated with Se exposure.