Mem medium

Mouse melanoma cell line B16-F10 (CRL-6475) was obtained from American Type Culture Collection (ATCC; Manassas, VA, USA). HEK293 cells stably expressing human LAT1 and human LAT2 (designated as HEK293-hLAT1 and HEK293-hLAT2, respectively) were established as described previously through transfection with plasmids encoding human LAT1 and human LAT2^{26 (link)}. B16-F10 cells were cultured in RPMI-1640 medium (Nacalai Tesque, Kyoto, Japan)^{48 (link)}. The HEK293-hLAT1 and HEK293-hLAT2 cells were maintained in MEM medium (Nacalai Tesque, Kyoto, Japan) supplemented with 1% non-essential amino acids (Wako, Osaka, Japan) and G418 disulfate (0.9 g/L, Nacalai Tesque, Kyoto, Japan)^{26 (link)}. Both cell media were supplemented with 10% fetal bovine serum (FBS, Nichirei Biosciences Inc., Tokyo, Japan) and a combination antibiotic consisting of 100 units/mL penicillin and 100 μg/mL streptomycin (Nacalai Tesque, Kyoto, Japan). Cells were incubated at 37 °C in a humidified atmosphere containing 5% CO₂.

CHO-K1 and a canine osteosarcoma cell line D-17 were purchased from the American Type Culture Collection (Manassas, VA, USA). Stable dog EGFR-overexpressed CHO-K1 (CHO/dEGFR) [26 (link)] and dog HER2-overexpressed CHO-K1 (CHO/dHER2) [27 (link)] were established as described previously. CHO-K1, CHO/dEGFR, and CHO/dHER2 were cultured in RPMI-1640 medium (Nacalai Tesque, Inc., Kyoto, Japan), containing 10% fetal bovine serum (FBS; Thermo Fisher Scientific, Inc., Waltham, MA, USA), 100 μg/mL streptomycin, 100 units/mL of penicillin, and 0.25 μg/mL amphotericin B (Nacalai Tesque, Inc.). D-17 was cultured in MEM medium (Nacalai Tesque, Inc.), supplemented with 10% FBS, 1 mM of sodium pyruvate, 100 units/mL of penicillin, 100 μg/mL streptomycin, and 0.25 μg/mL amphotericin B.