An estrogen-independent MCF-7 breast cancer cell line which contains a novel 80-kilodalton estrogen receptor-related protein
| Autor: | J J, Pink, S Y, Jiang, M, Fritsch, V C, Jordan |
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| Rok vydání: | 1995 |
| Předmět: |
Time Factors
Estradiol Polyunsaturated Alkamides Blotting Western Estrogen Antagonists Proteins Breast Neoplasms Transfection Recombinant Proteins Clone Cells Up-Regulation Molecular Weight Kinetics Tamoxifen Receptors Estrogen Protein Biosynthesis Tumor Cells Cultured Humans Electrophoresis Polyacrylamide Gel Female Luciferases Receptors Progesterone Cell Division |
| Zdroj: | Cancer research. 55(12) |
| ISSN: | 0008-5472 |
| Popis: | Long-term growth of estrogen-responsive human breast cancer cell lines in estrogen-free media leads inevitably to the development of estrogen-independent growth. We have identified and characterized a unique subclone of the MCF-7 human breast cancer cell line, named MCF-7:2A, which grows maximally in the absence of endogenous estrogens but whose growth is inhibited by the antiestrogens 4-hydroxytamoxifen and ICI 164,384. The MCF-7:2A cells express high levels of estrogen receptor (ER; 477 fmol/mg protein), which can be reduced by growth in 10 nM 17 beta-estradiol (201 fmol/mg protein). Basal progesterone receptor synthesis is very low in the 2A cells (1 fmol/mg protein) but can be dramatically increased by 10 nM 17 beta-estradiol (384 fmol/mg protein). Clearly, the pathways that control growth and estrogen-regulated genes such as the progesterone receptor are now dissociated in these cells. MCF-7:2A cells also possess two unique characteristics. First, the MCF-7:2A cells constitutively activate an ER-responsive luciferase reporter construct in the absence of any estrogens, and this activation can be blocked by either 4-hydroxytamoxifen or ICI 164,384. This constitutive activity is not observed in the parental MCF-7 cells. Second, they express an 80-kDa protein that cross-reacts with three distinct antibodies to the ER. The MCF-7:2A cells were subjected to an additional round of limiting dilution subcloning, and 10 independent clones were all shown to express both the 66- and 80-kDa ERs as observed in the MCF-7:2A line. This confirms that both ERs are being expressed in each cell and are not the result of a mixed population of cells. While numerous ER variants have been reported previously, no ER has until now been described that is larger than the wild-type 66-kDa ER. The MCF-7:2A cells provide a unique model to use in the study of ER action and the development of estrogen-independent growth in human breast cancer cells. |
| Databáze: | OpenAIRE |
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