Expression of Mn-Superoxide Dismutase Gene in Nontumorigenic andTumorigenic Human Mammary Epithelial Cells

摘要

Manganese superoxide dismutase (Mn-SOD), localizedat the mitochondrial matrix, has the ability to protect cellsagainst oxidative damage. It has been reported that low levels ofMn-SOD gene expression cause the development of certain kind oftumors. On the other hand, overexpression of Mn-SOD gene may playan important role in the development of cancer. In our study, wefind that Mn-SOD activity was higher in nonaggressive (MCF-7) andaggressive (BT-549 and 11-9-14) breast cancer cell lines comparedto that of nontumorigenic (MCF-12A and MCF-12F) mammaryepithelial cell lines. We also observed an increased expressionof Mn-SOD gene in cancerous cell lines. The elevated level of SODactivity in nonaggressive and aggressive breast epithelial celllines was associated with some changes in nucleotide sequence.