Figure 2 . Wnt/β -catenin signalling mediates melanogenesis, according to a correlation analysis performed in B16 cells. (a) Comparison of the effects of HCJA121 and HCJA404 on increasing the expression of the Axin2 , DKK1 , MITF ,TYR , and TYRP 1 and 2 genes in cells treated with Wnt3a-conditioned media and those that were not treated with Wnt3a-conditioned media. (b) Treatment with 20 μ M HCJA121 and HCJA404 increased the expression of the Axin2 , DKK1 ,MITF , TYR , and TYRP 1 and 2 genes with 8-MOP as the positive control, which was abolished by complementation with 5μ M XAV939, a Wnt inhibitor. B16 cells were treated with the compounds or compounds in combination with XAV939 for 48 h, and melanogenesis was determined by qPCR. (c) The induction of melanin content and tyrosinase activity by HCJA121 and HCJA404 (20 μ M) was blocked by 5 μ M Wnt inhibitor XAV939. The results represent the means ± S.E.M from five independent experiments (n=5). Data were analysed by ANOVA, significantly different as indicated (*P< 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001).