Characterization of progesterone receptor subunits in breast cancer cell line, CAMA-1N.
In order to study whether cytosolic progesterone receptor (PRc) is involved in progesterone-induced proliferative arrest of breast cancer cells (CAMA-1N), subunit composition of PRc in these cells was characterized. In the TSK G3000 high-performance liquid chromatography (HPLC) column, molybdate-stabilized PRc eluted as a single sharp peak immediately following the void volume. PRc from this peak had a sedimentation coefficient of 7.6 S and was eluted at 0.22 M salt from a linear gradient (0.1 to 0.4 M NaCl) in a DEAE column. When covalently labeled with [3H]R5020, analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and visualized by fluorography, PRc from crude cytosol exhibited two major protein bands with molecular weights of 105 +/- 2.1 and 83 +/- 3.2 kD, respectively. However, HPLC-purified PRc showed only one major band of 105 kD. These results show that PRc in CAMA-1N cells has steroid-binding components similar to other target tissues and provides a basis for further quantitative and qualitative analyses of PRc during cell proliferation and progesterone-induced growth arrest of CAMA cells.
Yu
W C
WC
Department of Obstetrics and Gynecology, University of Minnesota, Minneapolis 55455.
Leung
B S
BS
D001943:Breast Neoplasms / Q000032:analysis*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008970:Molecular Weight; D011980:Receptors, Progesterone / Q000032:analysis*; D014407:Tumor Cells, Cultured
D011980:Receptors, Progesterone