The estrogen receptor (ER)-positive human breast cancer line MCF-7 (RCB1904) and the ER-negative human breast cancer cell line MDA-MB-453 (RCB1192) were purchased from the RIKEN cell bank. MCF-7 cells were cultured at 37 °C with 5% CO2 in E-MEM with L-glutamine and phenol red (Wako Pure Chemical Industries, Ltd., Osaka, Japan) containing 10% fetal bovine serum (GE Healthcare Life Sciences, Inc., Logan, UT, USA), 1% penicillin/streptomycin (Wako Pure Chemical Industries, Ltd.), 1.0 mM sodium pyruvate solution (Wako Pure Chemical Industries, Ltd.), and 1% MEM non-essential amino acid solution (Thermo Fisher Scientific, Inc., Waltham, MA, USA). MDA-MB-453 cells were cultured at 37 °C without CO2 in Leibovitz′s L-15 Medium with L-glutamine, phenol red, and sodium pyruvate (Wako Pure Chemical Industries, Ltd.) containing 10% fetal bovine serum (GE Healthcare Life Sciences, Inc.) and 1% penicillin/streptomycin (Wako Pure Chemical Industries, Ltd.).
The hyperthermia treatment was based on our previous study [11 (link)]. The MCF-7 cells were incubated at 42 °C with 5% CO2 for 1 h using a standard incubator, and the MDA-MB-453 cells were incubated in the same way, but without CO2.
The hyperthermia treatment was based on our previous study [11 (link)]. The MCF-7 cells were incubated at 42 °C with 5% CO2 for 1 h using a standard incubator, and the MDA-MB-453 cells were incubated in the same way, but without CO2.