Comparison of Effects of Simple Sugars on 3T3 Mouse Fibroblasts and 3T3 Cells Transformed by Infection with Oncogenic Viruses

3T3 mouse fibroblasts, a cell line which ordinarily exhibits a high degree of contact inhibition in tissue culture, were markedly altered by addition of L-fucose to the growth medium. Such effects were not observed when equal amounts of different closely related sugars were substituted. When 3T3 cells were transformed by oncogenic viruses [simian virus 40 (SV40) or polyoma virus or sequential infection with both viruses], their susceptibility to changes caused by L-fucose was greatly reduced. Thus, virus-transformed cells grown in the presence of L-fucose showed much less of a change in the morphology of individual cells, their pattern of association, their rate of growth, and incorporation of protein and RNA precursors as compared to ordinary 3T3 cells. In the different cell lines tested, there was a general parallelism between degree of susceptibility to alteration by L-fucose and degree of contact inhibition. The mechanism by which L-fucose alters ordinary 3T3 cells, and the reasons for the difference in virus-transformed lines are unknown. However, the results raise the possibilities that L-fucose alters ordinary 3T3 cells by combining with complementary sites of these cells and that interactions between natural cellular sugar constituents and complementary sites play a role in mediating cell contact inhibition.