Secretion of prosaposin, a multifunctional protein, by breast cancer cells
| Autor: | W M Campana, Masao Hiraiwa, Stuart Patton, John S. O'Brien |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Programmed cell death
Cellular differentiation Biophysics Breast Neoplasms Biology Biochemistry Cathepsin D Culture Media Serum-Free Saposins Metastasis medicine Tumor Cells Cultured Humans Secretion Breast Molecular Biology Cell Line Transformed Glycoproteins Prosaposin Enzyme Precursors Dose-Response Relationship Drug Estradiol medicine.disease Cell biology Blot Cell culture Culture Media Conditioned biology.protein Antibody |
| Zdroj: | Biochimica et biophysica acta. 1427(3) |
| ISSN: | 0006-3002 |
| Popis: | Western blotting and immunodetection with three antibodies were used to probe conditioned media of breast cancer cells (MDA231, MDA435, MCF-7) for prosaposin, a lysosomal protein that occurs in milk. It was readily detected in media from these cells, and from that of an sv40-transformed mammary epithelial cell, HBL100, but not from medium of human neural tumor cells (SK-N-MC). In cultures of MCF-7 cells, the prosaposin pattern of secretion over time closely resembled that of procathepsin D, another lysosomal protein occurring in milk. Supplementing medium with 17beta-estradiol (0. 1-100 nM) dose dependently increased secretion of both proteins after 48 h without changes in cell viability. The influence of 17beta-estradiol on secretion could play a role in the trophic activity of prosaposin in cellular differentiation and cell death protection. In concert with other lysosomal proteins in the tumor environment, such as procathepsin D, prosaposin may be a factor in eliminating barriers to tumor metastasis by facilitating hydrolysis of membrane glycolipids. The number of milk proteins known to be secreted by breast cancer cells is growing. There is evidence that at least some of these may be secreted in an endocrine manner in the normal, non-lactating breast. |
| Databáze: | OpenAIRE |
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