Cell culture
The murine B16 melanoma cell line was purchased from the Type Culture
Collection of the Chinese Academy of Sciences (Shanghai, China). The B16
cells were cultured in HG-DMEM (Gibco Life Technologies, Waltham, MA,
USA). Wnt3a was added (2 ng/mL) to the media, followed by
supplementation with 10% FBS (BI, Biological Industries), penicillin G
(100 U/mL), and streptomycin (100 µg/mL) (Gibco-BRL, Grand Island, NY,
USA). The cells were maintained in a humidified incubator under 5%
CO2 at 37 °C, and they were sub-cultured every 2 days to
maintain logarithmic growth.