Breast Cancer Cell Culture and Transfection

MCF-7 and CCD-18Co cells obtained from ATCC (Manassas, VA, USA) were grown in Dulbecco’s modified Eagle medium (DMEM). T47D, BT-474, ZR-75-1, and HCC1428 cells obtained from Korean Cell Line Bank (KCLB, Seoul, Korea) were grown in Roswell Park Memorial Institute (RPMI) 1,640 medium supplemented with 10% fetal bovine serum. MCF-10A cells were maintained in DMEM/F12 supplemented with 5% horse serum, epidermal growth factor (EGF), hydrocortisone, cholera toxin, and insulin in 5% CO₂ at 37 °C. All the cell lines were tested for mycoplasma contamination and authenticated by STR DNA profiling. Tam-R cells were generated by a 12-month treatment of MCF-7 cells with 4-HT (1 μM).^{23 (link)} Transient transfection using Oligofectamine (Invitrogen, Carlsbad, CA, USA) was performed as described previously.^{21 (link)} Immunoblotting was performed using the antibodies listed in the Supporting Information Table 4.