Establishment of LTED Breast Cancer Cell Lines

Parental cancer cell lines (MCF-7, HCC-1428, T47D) were obtained from American Type Culture Collection (ATCC; Manassas, VA, USA), and LentiX cells were obtained from Clontech (Mountain View, CA, USA). MCF-7, HCC-1428, T47D, and LentiX cells were cultured in DMEM with 10% FBS (HyClone Laboratories; Logan, UT, USA). MCF-7/LTED cells were a gift from Matthew Ellis (Baylor College of Medicine, Houston, TX, USA) (45 (link)). HCC-1428/LTED cells were generated through long-term (>1 yr) culture in phenol-red-free DMEM with 10% dextran/charcoal-treated FBS (DCC-FBS; HyClone Laboratories) as previously described (46 (link)). LTED cells were maintained in phenol-red-free DMEM + 10% DCC-FBS supplemented with 2 mM GlutaMAX (ThermoFisher Scientific, Waltham, MA, USA), and were passaged using phenol-red-free 0.25% trypsin plus 2.21 mM EDTA (Corning, Tewksbury, MA, USA). Cell lines were verified by STR genotyping at the University of Vermont Cancer Center DNA Analysis Facility and confirmed to be free of mycoplasma (Universal Mycoplasma Detection Kit; ATCC). Assays were performed using cells cultured for <3 months thereafter.