Multicellular tumor spheroids in serum-free culture.
The serum-free culture of multicellular tumor spheroids from two rat (BT4c, BT5c) and two human (GaMg, D-54Mg) glioma cell lines is described. The spheroids were propagated in two different chemically defined media, showing differences in growth requirements between the human and rat cell lines. The spheroids from all the cell lines showed reduced growth rate as compared to spheroids maintained in serum supplemented culture. A change in spheroid morphology was observed for the D-54Mg cell line, indicated by a reduced occurrence of microvilli, increased pyknosis and cellular granularity. The other spheroids maintained their morphology in serum-free culture. For the D-54 Mg spheroids, flow cytometric DNA measurements showed that the serum-free growth conditions caused a drop in the DNA S-phase (6.4% vs. 12.3% in serum supplemented cultures). The cell cycle distribution was unchanged for the other cell lines tested. The present study provides the basis for using multicellular tumor spheroids in biological studies which are dependent on a detailed control with chemical environment.