Culturing Adriamycin-Resistant Breast Cancer Cells

Normal epithelial breast cell line MCF-10A and breast cancer cell line MCF-7 were purchased from the Cell Bank of Type Culture Collection of Chinese Academy of Sciences (Shanghai Institute of Cell Biology, Shanghai, China). MCF-10A cells were maintained in a mixed medium as per Qin's method 9 (link). adriamycin-resistant MCF-7/ADR cells were screened from MCF-7 cells in the optimal growth state after being exposed to different concentrations of adriamycin (MedChemExpress, Shanghai, China). MCF-7 cells were cultured in DMEM F12 supplemented with 10% FBS. MCF-7/ADR cells were cultured in RPMI 1640 media supplemented with 10% FBS. All media were supplemented with 100 unit/mL penicillin, and 100 μg/mL streptomycin, and all cells were incubated at 37 °C in a 5% CO₂ atmosphere. Specifically, to sustain the multidrug resistant phenotype, MCF-7/ADR cells were cultured in the medium supplemented with adriamycin (4 μg/ml). Before in vitro assay, all cells were cultured in a drug-free medium for 24 hrs.