Cell lines and culture

Human breast cancer cell lines (MDA-MB-231, MCF-7, and ZR-75-1) were purchased from ATCC (Manassas, VA, USA) and cultured in high-glucose Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 1% penicillin, and 1% streptomycin. The cell line SUM1315 was kindly provided by Stephen Ethier (University of Michigan). The MDA-MB-231br cell line was established in a previous study [10]. All cells were incubated at 37°C in a humidified chamber supplemented with 5% CO₂.