BCL-2, Ca, and Apoptosis in Breast Cancer
Abstract
31EG4 mammary epithelial cells were grown to confluence on filters, and apoptosis was initiated by staurosporine and mitomycin (kinase inhibitors) and also by thapsigargin (releases Ca stores by blocking Ca pump) and collagenase IV (degrades extracellular matrix). As shown by specific staining with fluorescent dyes, apoptosis began to occur in a small percentage of cells (after 16 hrs) as shown by condensation and fragmentation of the nuclei accompanied by extracellular membrane appearance of phosphatidylyserine (annexin V staining) . After 48 hrs, a majority of cells were undergoing apoptosis or had been killed. Although cytosolic Ca was the same in both control and apoptosing cells, stores of Ca (likely in the ER) were more than 50% smaller in the apoptosing cells compared to controls. As shown by deconvolution microsopy, these apoptosing cells exhibited prominent stores of Ca in the center of the fragmenting nucleus, which appeared to surround the store. These results may indicate an intimate relationship between the store and nuclear fragmentation. Further studies using electrophysiolgical methods showed that control mammary epithelial cells exhibit polarized Na absorption and Cl secretion that could contribute to control of milk secretion and also to fluid accumulation in mammary cysts.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1999
- Accession Number
- ADA384066
Entities
People
- Terry E. Machen
Organizations
- University of California, Berkeley