Altered growth behavior of virus-transformed cells after treatment with dextran sulfate

Growth behavior in vitro of 3T3 cells and the cells transformed by polyoma or SV40 virus was studied after their treatment with dextran sulfate. The transformed cells treated with dextran sulfated showed decreased saturation density compared with untreated cells, whereas saturation density of 3T3 cells was hardly affected by treatment with dextran sulfate. The ratio of saturation density of untreated SV3T3 cells to that of the treated cells was 64.1% at 5 microng/ml and was 43.4% at 10 microng/ml of dextran sulfate. In Py3T3 cells the ratio was 45.0% at both concentrations of 10 and 20 microng/ml. Plating efficiency was not affected in 3 cell lines tested after treatment with dextran sulfate. The treated cells showed a tendency to form thin and not piled-up colonies in the central area. The treated SV3T3 and Py3T3 cells were flattened in shape compared with the untreated cells. In agar medium the treated SU 3T3 and Py 3T3 cells showed the tendency to stop growing after forming small colonies, whereas the untreated cells kept growing anf formed large colonies. These results suggested that dextran sulfate altered temporarily the growth of the transformed cells to that of untransformed cells.