Promotional effect of lithocholic acid and 3-hydroxyanthranilic acid on transformation of X-ray-initiated BALB/3T3 cells.

X-ray-irradiated BALB/3T3 A31-1-1 cloned cells were post-treated with lithocholic acid (LCA), one of the bile acids, and 3-hydroxyanthranilic acid (3HOA), a tryptophan metabolite, in order to examine their potential to promote cell transformation. Insulin was added to the medium so as to increase the sensitivity of the cells to transformation. A dose-dependent increase in the number of transformed foci was observed with LCA. 3HOA had a very weak, though significant, activity. Transformation frequency was increased only a little, if any, by the treatment with cholic acid, which is structurally related to LCA. Anthranilic acid, an analogue of 3HOA, had no such effect. The results are discussed in view of the importance of endogenous promoters.