Production by lithocholic acid of DNA strand breaks in L1210 cells.

Bile acids have been reported to promote colon cancer cells in mice treated with different carcinogens. In this study, we investigated the effects of lithocholic acid on the DNA of mouse lymphoblastoma L1210 cells. Incubation of L1210 cells with lithocholic acid (2.5 X 10(-4) M) at 37 degrees for 30 min and for 1 hr resulted in the appearance of single-strand breaks in the DNA. This was demonstrated by sedimentation of nucleoids in neutral sucrose gradients and by alkaline elution. The DNA damage was repaired upon incubation of the cells in fresh medium lacking lithocholic acid. These results suggest that DNA repair efficiency is an important function for the population of cells which are constantly exposed to low concentrations of lithocholic acid. The presence of even a low level of persistent damage could lead to significant biological consequences including mutations and the induction of error-prone repair processes.