Bt549

Human breast cancer MDA-MB-231, BT-549, MDA-MB-468, BT-474, BT-20 and MCF-7 cell lines (American Type Culture Collection, ATCC, Manassas, VA) were grown in RPMI-1640 (Invitrogen, Carlsbad, CA, USA) (MDA-MB-231, BT-549 and MDA-MB-468), ATCC HybriCare Medium (BT-474) or Dulbecco’s modified Eagle’s medium (Invitrogen) (BT-20 and MCF-7) supplemented with 10% fetal bovine serum (FBS) (Invitrogen), in 95% air/5% CO2 atmosphere at 37 °C. Growth conditions for mouse NIH3T3 cells were previously reported26 (link).

The Broad Institute Cancer Cell Line Encyclopedia (CCLE) was used to compare the expression of MCT isoforms in 57 breast cancer cell lines. RNA expression (RNAseq) data, expressed as log₂ (fold change) (FC) were plotted using Prism7 (GraphPad, CA, USA). Co-expression of MCT1 and MCT2 (high affinity isoform) or MCT4 (low affinity isoform) was evaluated. BT20, MDA-MB-231, MDA-MB-468, and BT549 cells were purchased from the American Type Culture Collection (ATCC) and cultured in Dulbecco’s Modified Eagle Medium (DMEM), except BT549 which was cultured in RPMI, supplemented with 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin/l-glutamine. Cell lines were maintained at 37 °C in a humidified, 5% CO₂ atmosphere (HeraCell™ 150 incubator, Thermo Fisher Scientific, Waltham, USA) and sub-cultured using trypsin-EDTA 0.05% solution. Cells were tested monthly and found to be mycoplasma-free. Cells were discarded at passage number 25 or lower, counting from the original ATCC stock. MDA-MB-231, MDA-MB-468, and BT20 cells were authenticated by ATCC.

The human breast cancer cell lines MDA-MB-231, BT549, Hs578T, HCC1806, and the mouse breast cancer cell line 4T1 were purchased from the American Type Culture Collection (ATCC) and maintained in 10% FBS DMEM media at 37°C and 5% CO₂.
The BT549-topotecan resistant line was generated by gradually increasing topotecan concentrations until growing cells became resistant to a topotecan concentration of 1 µM. Resistant cells were then maintained in 10% FBS DMEM media containing 1 µM topotecan at 37°C and 5% CO₂.
The Caov3 and Kuramochi ovarian cancer cell lines from the Sandra Orsulic lab at Cedars-Sinai were maintained in 10% FBS RPMI 1640 media at 37°C and 5% CO₂.
PDX5 p6, PDX6 p8, and PDX4 p7 56 (link) (from the Julia Unternaehrer lab at Loma Linda University School of Medicine) were maintained in media containing F12 and DMEM with a ratio of 3:1 respectively, 5% FBS, 0.4 µg/mL hydrocortisone, 5 µg/mL insulin, 8.4 ng/mL cholera toxin, 24 µg/mL adenine at 37°C and 5% CO₂.