Related Experiment Videos
Estrogen inhibits the growth of MCF-7 cell variants resistant to transforming growth factor-beta
Y Hagino1, M Mawatari, A Yoshimura
1Department of Biochemistry, Oita Medical School.
Abstract:
Human breast cancer MCF-7 cells containing estrogen receptor are killed by transforming growth factor-beta (TGF-beta). We isolated variants of MCF-7 highly resistant to TGF-beta. Variants ES-1 and ES-4 were cloned, and the growth of ES-1 and ES-4 was found to be inhibited by estradiol, whereas estradiol stimulated the growth of the parental MCF-7 cells. ES-1 cells contained about 2-fold higher level of estradiol receptor than MCF-7 cells. Addition of estradiol to the culture medium for MCF-7 and the variant changed the expression of several secreted proteins. The repertoire of secreted proteins was markedly altered in the variant. Polypeptides of molecular weight 52,000 (52 K), 65 K and 160 K were increased about 10- to 50-fold in both estradiol-treated MCF-7 and ES-1 cells. Polypeptide of 130 K was decreased in estradiol-treated ES-1 cells while this polypeptide was increased about 4-fold in estradiol-treated MCF-7, as compared with untreated MCF-7. Polypeptide of 100 K was specifically secreted in ES-1 whether or not estradiol was present, but there appeared to be no significant amount of the 100 K protein in MCF-7. The estradiol-hypersensitive phenotype is discussed in relation to its aberrant expression of secreting proteins.
Insights
Transforming growth factor-beta (TGF-beta) resistance in human breast cancer cells (MCF-7) led to estradiol-hypersensitive variants. These variants exhibit altered secreted protein profiles, impacting cancer cell growth and response to estradiol.
Area of Science:
- Cell Biology
- Molecular Biology
- Endocrinology
Background:
- Human breast cancer MCF-7 cells are sensitive to transforming growth factor-beta (TGF-beta).
- Estradiol typically stimulates growth in estrogen receptor-positive breast cancer cells.
Purpose of the Study:
- To isolate and characterize MCF-7 cell variants resistant to TGF-beta.
- To investigate the growth response of these variants to estradiol.
- To analyze changes in secreted proteins associated with altered estradiol sensitivity.
Main Methods:
- Isolation and cloning of TGF-beta-resistant MCF-7 variants (ES-1, ES-4).
- Assessment of cell growth inhibition/stimulation by estradiol.
- Quantification of estradiol receptor levels.
- Analysis of secreted proteins using gel electrophoresis and densitometry.
Main Results:
- TGF-beta-resistant variants (ES-1, ES-4) showed estradiol-induced growth inhibition, unlike parental MCF-7 cells.
- ES-1 cells possessed approximately double the estradiol receptor levels compared to MCF-7 cells.
- Estradiol treatment altered the expression of several secreted proteins in both MCF-7 and variant cells.
- Specific polypeptides (52 K, 65 K, 160 K) increased significantly with estradiol in both cell types.
- A 130 K polypeptide decreased in estradiol-treated ES-1 cells but increased in estradiol-treated MCF-7 cells.
- A 100 K polypeptide was uniquely secreted by ES-1 cells, irrespective of estradiol presence.
Conclusions:
- The development of TGF-beta resistance in MCF-7 cells can lead to an estradiol-hypersensitive phenotype.
- Aberrant expression of specific secreted proteins is associated with this altered estradiol sensitivity.
- These findings highlight complex regulatory mechanisms in breast cancer cell response to growth factors and hormones.