A novel culture system to induce melanin synthesis by three-dimensional spheroid culture

Three-dimensional (3D) spheroid culture has recently become a valuable tool to evaluate the utility of treatments that better mirror biological features and exhibit high concordance with in vivo conditions. Here, by using the 3D spheroid method, we investigated cell morphology, proliferation, melanin content, tyrosinase activity, and cAMP production. During 3D speroid cultures, melanin biosynthesis was observed and the amount of melanin continuously increased until cell proliferation slowed down. Up-regulation of the cAMP pathway enhanced tyrosinase activity, allowing melanin synthesis. However, after treatment with depigmenting agents, melanin content was reduced. These results indicate that 3D spheroid culture method is an important tool to study melanin biosynthesis, which enables us to overcome several limitations found in the 2D adherent cell culture mehtod.