Inhibition of chemically induced neoplastic transformation in vitro by saturated fatty acids

Syrian hamster embryo cells were treated for 2-4 days with 3-methylcholanthrene (MCA), and 28 days after application of the carcinogen they were exposed continuously to 12-O-tetradecanoylphorbol-13-acetate (TPA). Untreated cells, or cells treated with MCA or TPA only, usually became senescent around 6-8 weeks after plating and died, but those treated with both MCA and TPA became immortalised and underwent transformation to a phenotype capable of growth in soft agar. Transformation was inhibited by derivatives of stearic acid administered to the cells at various stages of the overall process. Some derivatives were active at lower concentrations than others, but none were selective for specific phases such as initiation or promotion, and it did not appear to matter whether the fatty acids were present throughout the assay or for only part of it. Their action seems to be associated with control of growth or differentiation in a relatively non-specific manner.