title: Hypersensitivity and growth adaptation of oestrogen-deprived MCF-7 human breast cancer cells.
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.
  
  
  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.
  
  
  CONCLUSIONS
  Hypersensitivity can develop without any growth adaptation and therefore is not a prerequisite for loss of growth response in MCF-7 cells.
authors.affiliation: School of Biological Sciences, University of Reading, Hopkins Building, Whiteknights, Reading RG6 6UB, U.K. p.d.darbre@reading.ac.uk.
authors.forename: Philippa D
authors.initials: PD
authors.lastname: Darbre
mesh_terms: D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008156:Luciferases / Q000378:metabolism; D061986:MCF-7 Cells; D011960:Receptors, Estrogen / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D004967:Estrogens; D011960:Receptors, Estrogen; D008156:Luciferases
keywords: Hypersensitivity; MCF-7 cells; breast cancer; insulin; oestrogen deprivation