Induction of glutathione-S-transferase-pi by short-chain fatty acids in the intestinal cell line Caco-2.

Glutathione S-transferases (GSTs) are a multigene family of detoxification and metabolizing enzymes that have been linked with the susceptibility of tissues to environmental carcinogens. In addition to their role as the main energy source in the colonic mucosa, short-chain fatty acids (SCFAs) have been found to act as potent antiproliferative and differentiating agents in various cancer cell lines. The objective of this study was to evaluate the effects of SCFAs on the induction of GSTpi in the intestine as a possible new anticarcinogenic mechanism of SCFAs. Studies were performed in Caco-2 cells, a cell line resembling functionally normal enterocytes. Cells, cultured in DMEM supplemented with 10% fetal calf serum, were studied from day 0 dpc (days post confluence) until 21 dpc and culture. SCFAs (acetate, propionate, butyrate) were added to give a final concentration of 5 mmol L(-1). At 0, 3, 6, 9, 15, and 21 dpc, protein, lactate dehydrogenase (LDH), alkaline phosphatase (AP) and GSTpi were measured. Butyrate supplementation significantly (P < or = 0.01) increased GSTpi levels compared with controls in a concentration-dependent manner. The effect was detectable within 3 dpc with a maximum at 15 dpc. In contrast to butyrate, the other SCFAs tested had no (acetate) or little effect (propionate). In conclusion, the data suggest that the anticancer effect of butyrate in part may be based on the induction of GSTpi activity, resulting in an enhanced detoxification capacity of the gut.