The Role of Oxidative Stress in Apoptosis of Breast Cancer Cells.
Abstract
Our long-term goal is to use an understanding of apoptosis to improve the treatment of breast cancer. This project is aimed at testing the hypothesis that oxidative stress plays a critical role in the mechanism of apoptosis induced by treatment of human breast cancer cells with tumor necrosis factor-a (TNF). Using northern blot hybridization analyses and biochemical assays, we have demonstrated a selective increase in the antioxidant defense enzyme manganese superoxide dismutase (MnSOD) in TNF-treated MCF-7 cells. The increase in MnSOD was most pronounced in cells that remaln viable after exposure to TNF. This finding is consistent with reports of a protective effect of MnSOD against TNF-induced cytotoxicity and may be related to the role of mitochondria in apoptosis. We have transfected MCF-7 cells with antioxidant defense gene to test whether this alters the cells' response to TNF. In order to compare TNF responses between transfectants, we used Sulfarhodamine B assays with cells plated at various densities and analyzed by an Analysis of Covanance statistics model. Stable DT-diaphorase transfectants were found to more sensitive to TNF. This suggests that DT-diaphorase may act on cellular substrates to generate apoptosis-promoting reactive species.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1998
- Accession Number
- ADA366950
Entities
People
- Margaret M. Briehl
Organizations
- University of Arizona