Growth of malignant tumors occurs in three-dimensional space and depends on a presence of stromal component, which performs critical functions of tumor cell protection and growth support. Therefore, development and analysis of tumor models in 3D cell cultures in vitro, including co-culture systems, presents a significant interest. In this study, the results of 3D culturing of two human melanoma cell lines using the hanging drop method, with or without human mesenchymal stem cells (MSCs), are presented. Melanoma lines were shown to behave differently in 3D cultures; in particular, Mel Cher melanoma cells have the ability to form uniform spheroids within 24 h, whereas MeWo cells under similar conditions failed to form spheroids even after 2 days of culture. However, co-culturing of melanoma cells with MSCs resulted in formation of compact 3D cell spheroids in both cases. Visualization of MeWo cells and MSCs in the mixed spheroids using fluorescent dyes revealed certain clustering of melanoma cells. The observed properties of melanoma cells in homogeneous and heterogeneous spheroids may be used in the complex analysis of results of testing of antimelanoma chemotherapy drugs and evaluation of their therapeutic properties.
Keywords: MeWo cell line; coculture; human mesenchymal stem cells; melanoma; spheroids.