2.1 Cell culture and animal models
The human melanoma cell lines A375, SK-Mel-28, and HMVII and the human non-small cell lung cancer cell line A549 were obtained from Procell Life Science & Technology Co., Ltd.; A375, SK-Mel-28, and A549 were cultured in standard Dulbecco’s modified Eagle’s medium or RPMI-1640 (Bioskan) supplemented with penicillin (Bioskan), streptomycin (Invitrogen), and FBS (Sigma‒Aldrich) at 37 °C in a 5% CO2 atmosphere; and HMVII was cultured in Ham’s F-10 Nutrient Mixture (Giboco) supplemented with 10% FBS [Sigma‒Aldrich] at 37 °C with 5% CO2. When the cells reached ~ 80% confluence, they were used for in vitro and in vivo experiments.
A375 and HMVII tumor xenografts were induced in 4- to 5-week-old female athymic nude mice (Beijing Vital River Laboratory Animal Technology Co., Ltd.) via the injection of 1 × 106 cells (suspended in 100 μL of PBS) into the underarm. For the SK-Mel-28 and A549 cell models, cells were suspended in 100 μL of a 1:1 mixture of PBS and Matrigel (BD Biosciences), and the animals were used for in vivo experiments ∼3 weeks after implantation when the tumors reached in diameter. Human melanoma PDX models were generated by Department of Renal Melanoma, Peking University. All animal experiments were completed in accordance with the relevant guidelines and regulations of Beijing Cancer Hospital.