Fetal bovine serum (fbs)

Luciferase-expressing cell lines derived from human gastric adenocarcinoma (MKN-45), breast adenocarcinoma (MCF-7) and hepatocellular carcinoma (HuH-7), were obtained from the Japanese Collection of Research Bioresources (Osaka, Japan). MKN-45 cells were maintained in RPMI1640 Glutamax medium (Thermo Fisher Scientific, Tokyo, Japan) supplemented with 10% fetal bovine serum (FBS; Equitech-Bio, Kerrville, TX) in an atmosphere of 5% CO₂ at 37 °C. MCF-7 and HuH-7 cells were maintained in Dulbecco’s minimal essential medium (DMEM; Thermo Fisher Scientific) instead of RPMI1640. Two Chinese hamster ovary (CHO) cell lines, human CEA-expressing CHO-CEA and human EpCAM-expressing CHO-EpCAM cells, have been described previously [5 (link)], and were cultured in α-modified minimum essential medium (α-MEM; Thermo Fisher Scientific) supplemented with 10% FBS and 2 mM glutamine. Murine tumor endothelial cell line 2H-11 was obtained from the American Type Culture Collection (Manassas, VA) and was maintained in DMEM supplemented with 10% FBS and 2 mM glutamine (Wako Pure Chemicals, Osaka, Japan). Primary human breast CAF derived from an infiltrating ductal-carcinoma tissue was purchased from Asterand (Detroit, MI) and maintained in DMEM supplemented with 10% FBS and penicillin–streptomycin.

BmN4 cells were cultured at 26 °C in EX-CELL^® 420 Serum-Free Medium for insect cells (Sigma) supplemented with 10% fetal bovine serum (Equitech-Bio) and penicillin-streptomycin-glutamine (Thermo Fisher Scientific).

Rat islet isolation was performed as previously described [18 (link)]. After cannulating the bile duct, 10 mL of cold HBSS containing the enzyme blends was injected followed by the removal of the pancreas. After digestion at 37°C for 14 min, purification by a density-gradient centrifugation was performed using a Histopaque-1119 (Sigma Diagnostics, St. Louis, MO, USA) and Lymphoprep (Axis-Shield PoC AS, Oslo, Norway). The islet count was determined as islet equivalents (IEQs) with diphenylthiocarbazone (Wako Pure Chemical Industries, Ltd., Osaka, Japan) staining. The isolated islets were cultured in Roswell Park Memorial Institute-1640 medium containing 5.5 mmol/L glucose (Thermo Fisher Scientific, Inc., Waltham, MA, USA) and 10% fetal bovine serum (Equitech-Bio, Inc., Kerrville, TX, USA) at 37°C in 5% CO₂ and humidified air.

All animal experimental protocols were approved by the RIKEN Animal Welfare Committee and were conducted in accordance with the National Institutes of Health Principles of Laboratory Animal Care. All applicable institutional and/or national guidelines for the care and use of animals were followed. All animal results are reported following ARRIVE guidelines.
The LNZ308 human glioblastoma cell line, which has been confirmed to express LAT1^{22 (link)}, was a kind gift from Prof. Motoo Nagane of Department of Neurosurgery, Kyorin University, Japan. LNZ308 cells were cultured in Dulbecco's modified Eagle's medium (Nacalai Tesque, Inc., Kyoto, Japan) supplemented with 10% fetal bovine serum (Equitech-Bio, Inc., Kerrville, TX), 100 units/mL penicillin, and 100 μg/mL streptomycin (Nacalai Tesque, Inc.)^{38 (link)}. LNZ308 cells were inoculated into the right forepaws of female BALB/cAJcl-nu/nu nude mice (CLEA Japan, Inc., Tokyo, Japan) via subcutaneous injection of 5 × 10⁶ cells in 100 μL Hank's balanced salt solution (Thermo Fisher Scientific, Waltham, MA)^{38 (link)}. Tumor growth was monitored twice a week using a caliper.