4t1 breast cancer cell

Erbium acetate hydrate (III), lutetium acetate hydrate (III), ammonium fluoride (NH₄F), oleic acid, 1-octadecene, ammonium hydroxide solution, polyacrylic acid (Mw 1,800), hemoglobin (Hb; bovine), bovine serum albumin (BSA), and kerosene were purchased from Sigma-Aldrich (St. Louis, MO, USA). Chlorin e6 (Ce6) was purchased from Frontier Scientific (Salt Lake City, UT, USA). Icosafluoro-15-crown-5-ether (PFC) was purchased from Tokyo Chemical Industry Co., LTD. (Tokyo, Japan). SY-Glyster CR-310 was kindly provided by Sakamoto Yakuhin Kogyo Co. (Osaka, Japan). 4T1 breast cancer cells were obtained from the American Type Culture Collection (ATCC; Rockville, MD, USA). LIVE/DEAD™ viability/cytotoxicity assay kits, singlet oxygen sensor green reagent (SOSG), and CellROX™ Green reagent were purchased from Thermo Fisher Scientific (Waltham, MA, USA). Anti–HIF–1α primary and Alexa Fluor®-488-conjugated goat anti-rabbit secondary antibodies were purchased from Abcam (Cambridge, MA, USA). In situ cell death detection (terminal deoxynucleotidyl transferase dUTP nick end labeling: TUNEL) assay kits were purchased from Roche Diagnostics GmbH (Mannheim, Germany). Hypoxyprobe™-1 Plus kits were obtained from Hypoxyprobe Inc. (Burlington, MA, USA). All other reagents were obtained from Sigma-Aldrich unless otherwise indicated.

NIH/3T3 cells were acquired from the American Type Culture Collection and cultured in DMEM (Dulbecco’s modified Eagle’s medium) (GIBCO) supplemented with 10% fetal bovine serum (FBS) and 1% penicillin-streptomycin (Hyclone) at 37°C under humid conditions with 5% CO₂. 4T1 breast cancer cells and H22 mice hepatoma cells were acquired from the American Type Culture Collection and cultured in RPMI 1640 (GIBCO) supplemented with 10% FBS and 1% penicillin-streptomycin (Hyclone) at 37°C in a humidified environment containing 5% CO₂.

The murine 4T1 breast cancer cells were purchased from American Type Culture Collection (Rockville, MD, USA). The 4T1 cells were cultured in RPMI 1640 medium supplemented with 10% (v/v) FBS and penicillin/streptomycin (100 U/ml of each), and maintained in a cell incubator at 37  °C with 5% CO₂. In some experiments, the culture medium was added with 10 mM lactic acid to mimic the acidic condition. The hypoxic condition was induced using a hypoxia incubator with conditions set at 2% O₂, 5% CO₂, and 93% N₂.
BALB/c female mice (6–8 weeks, 20–25 g) were acquired from Shanghai Silaike Laboratory Animal Co., Ltd (Shanghai, China). All animal procedures were performed in accordance with the Guidelines for Care and Use of Laboratory Animals of Lishui University and approved by the Animal Ethics Committee of Lishui University. The unilateral subcutaneous tumor-bearing murine models were inoculated by injecting 4T1 cells into the right armpit of the mice. The bilateral subcutaneous tumor-bearing murine models were inoculated by injecting 4T1 cells into their right and left flanks at Day 7and 3, respectively.