Deoxycholic acid stimulates migration in colon cancer cells

Background Deoxycholic acid and other secondary bile acids have long been considered tumour promoters in the colon. However, their effect on cell migration, known to play an important role in colon carcinogenesis, has not been studied so far. Objective To investigate the possible effects of deoxycholic acid on colon cancer-cell migration in culture. Methods Human colon carcinoma cells (Caco-2) were seeded on basement membrane matrix, To evaluate replication-blocked cell migration, we wounded confluent monolayers of cells with a sterile scalpel, and inhibited cell replication with mitomycin C. Immediately after wounding, the cells were exposed to 0-100 mu mol/l deoxycholic acid. Migration over 72 h was monitored using a phase contrast microscope. Results Replication-blocked migration was stimulated by deoxycholic acid in a dose-dependent manner, with the maximum effect at 20 mu mol/l deoxycholic acid. Enhancement of migration rate was unaffected by immunoneutralization of transforming growth factor beta (a known migration-promoting peptide). However, specific inhibition of protein kinase C markedly inhibited deoxycholic acid-induced Caco-2 cell migration. Conclusion In addition to its well-established role in the enhancement of proliferation, deoxycholic acid also stimulates colon cancer-cell migration along the basement membrane matrix. The mechanism of this stimulation is likely to involve protein kinase C. Deoxycholic acid-stimulated migration might additionally contribute to the tumour-promoting effects of secondary bile acids in the colon. Eur J Gastroenterol Hepatol 13:945-949 (C) 2001 Lippincott Williams & Wilkins.