@article {DARBRE99, author = {PHILIPPA D. DARBRE}, title = {Hypersensitivity and Growth Adaptation of Oestrogen-deprived MCF-7 Human Breast Cancer Cells}, volume = {34}, number = {1}, pages = {99--105}, year = {2014}, publisher = {International Institute of Anticancer Research}, abstract = {Background: Efficacy of endocrine therapy is compromised when human breast cancer cells circumvent imposed growth inhibition. The model of long-term oestrogen-deprived MCF-7 human breast cancer cells has suggested the mechanism results from hypersensitivity to low levels of residual oestrogen. Materials and Methods: MCF-7 cells were maintained for up to 30 weeks in phenol-red-free medium and charcoal-stripped serum with 10-8 M 17β-oestradiol and 10 μg/ml insulin (stock 1), 10-8 M 17β-oestradiol (stock 2), 10 μg/ml insulin (stock 3) or no addition (stock 4). Results: Loss of growth response to oestrogen was observed only in stock 4 cells. Long-term maintenance with insulin in the absence of oestradiol (stock 3) resulted in raised oestrogen receptor-alpha (ERα) levels (measured by western immunoblotting) and development of hypersensitivity (assayed by oestrogen-responsive reporter gene induction and dose response to oestradiol for proliferation under serum-free conditions), but with no loss of growth response to oestrogen. Conclusion: Hypersensitivity can develop without any growth adaptation and therefore is not a prerequisite for loss of growth response in MCF-7 cells.}, issn = {0250-7005}, URL = {https://ar.iiarjournals.org/content/34/1/99}, eprint = {https://ar.iiarjournals.org/content/34/1/99.full.pdf}, journal = {Anticancer Research} }