Inhibition by 1-beta-D-arabinofuranosylcytosine of the incorporation of N-acetylneuraminic acid into glycolipids and glycoproteins of hamster embryo cells

1-β-D-Arabinofuranosylcytosine which interferes with DNA synthesis in bacteria and mammalian cells and brings about transformation of hamster embryo fibroblasts, has been found to inhibit the incorporation of N-Acetylneuraminic acid into glycolipids and glycoproteins of both normal and transformed hamster embryo cells in tissue culture. Three hours after commencement of treatment (10^?3M ara-C), incorporation of ¹⁴C] thymidine into DNA was inhibited by 95 per cent, while incorporation of ³H] D-glycosamine (precursor of sialic acid) into glycolipids and glycoproteins was inhibited by 85 per cent. At 24 hours, the inhibition of incorporation of the two labelled components was 83 and 80 per cent respectively. In homogenates of both cell types, incorporation of ¹⁴C] N-acetylneuraminic acid was competitively inhibited by ara-CMP. Ara-C was found to have no effect on the incorporation of ¹⁴C] choline into phospholipids of cells grown in tissue culture. These results suggest that interference with DNA synthesis by ara-C may not be the only factor involved in cell transformation by this substance.