Three-dimensional culture of human tumor cells under standardized medium conditions

The 3-dimensional culture of human tumor spheroids under standardized medium conditions may reveal information on specific biological parameters that could be masked in serum-supplemented media. Spheroids derived from human tumor cells are growth retarded in media free of serum. Ex-Cyte IV is a substance derived from human blood that can be used to improve growth in tissue culture. In this study the growth of spheroids from four different human tumor cell lines was studied when grown in medium free of serum, medium supplemented with varying concentrations Ex-Cyte IV, and medium supplemented with foetal calf serum (FCS). The parameters used for comparisons were growth rate, growth enhancement, clonogenicity and cell cycle distribution. The four cell lines showed different growth rates in serum-free medium, which were increased to different extents when Ex-Cyte IV or FCS were added. The growth enhancing effect induced by Ex-Cyte IV was differently concentration dependent for each cell line. The clonogenicity of cells grown as spheroids in serum-free medium was lower than in spheroids grown in supplemented media. There was no difference in clonogenicity between the differently supplemented media. All four cell lines responded to growth in serum-free medium with a drop in the S-phase and G2M phase. The present study provides a novel approach to the study of human tumor cells in 3-dimensional culture under defined conditions. The human serum derived substance Ex-Cyte IV may provide a method to obtain information on specific biological parameters that could be masked in serum-supplemented media.