4t1 mouse mammary carcinoma cells

4T1 mouse mammary carcinoma cells were purchased from American Type Culture Collection (ATCC) and were maintained in RPMI medium 1640 supplemented with 10% (v/v) heat-inactivated fetal bovine serum (FBS) and 100 units/mL penicillin-streptomycin. Primary culture of 4T1 tumour cells was also isolated from 3 tumour-bearing mice and maintained. Tumour cells were allowed to grow until they reached 70% to 80% confluence and subjected for the RA-XII treatment. All the culture media, FBS and supplements were obtained from Life technologies (USA). Cells were incubated at 37 °C in a humidified atmosphere of 5% CO₂. The cells obtained from ATCC were immediately expanded and frozen down such that all cell lines could be restarted every 3–4 months from a frozen vial of the same batch of cells. Once resuscitated, cell lines were routinely authenticated through cell morphology monitoring and growth curve analysis.

MC38 mouse colon carcinoma cells (Kerafast Inc., Boston, MA) were maintained in DMEM supplemented with 10% FBS, 1 mM glutamine, 0.1 M non-essential amino acids (Thermo Fisher, Waltham, MA), 1 mM sodium pyruvate, 10 mM HEPES, 100 U/ml penicillin, and 100 µg/ml streptomycin. 4T1 mouse mammary carcinoma cells and Renca mouse renal carcinoma cells were purchased from American Type Culture Collection (ATCC) and cultured in RPMI medium supplemented with 10% FBS, 100 U/ml penicillin, and 100 µg/ml streptomycin. Py8119 mouse mammary carcinoma cells^{37 (link)} were obtained from Dr. Lesley Ellies at the University of California San Diego and cultured in DMEM supplemented with 10% FBS, 100 U/ml penicillin, and 100 µg/ml streptomycin. All cells were cultured at 37 °C and 5% CO₂ in a humidified incubator.