Maintenance of Breast Cancer Cell Lines

MDA-MB-231, T47D and HEK293 were maintained in Dulbecco’s-Modified Eagle’s Medium (DMEM) supplemented with 10% fetal calf serum (FCS) and 2 mM l-glutamine (complete growth medium). Parental MCF7 were maintained as mentioned earlier but with addition of 10 nM estradiol. Tamoxifen-resistant (TamR) and fulvestrant-resistant (FulvR) MCF7 derivatives were maintained in complete growth medium with addition of 100 nM tamoxifen or fulvestrant, respectively. The long-term estrogen deprived (LTED) MCF7 derivative line was maintained in phenol red-free DMEM supplemented with 10% charcoal-dextran-stripped FCS (csFCS) and 1% l-glutamine. MCF7, TamR and LTED cells were a kind gift from Dr Luca Magnani (Imperial College London, UK) and FulvR, MDA-MB-231 and T47D were kindly provided by Prof Simak Ali (Imperial College London, UK). All cell lines were kept at 37°C in a humidified atmosphere with 5% CO₂.