Divergent effects of butyrate on the alkaline phosphatases of SW-620 cells

The human colon cancer cell line SW-620 produces two alkaline phosphatases (ALPs) which are not expressed by normal colon. They are the heat-stable, term-placental and the heat-labile, L-homoarginine-sensitive, liver/bone/kidney ALPs. Butyrate, an ALP inducer, has strikingly dissimilar effects on the activity of these enzymes: whereas high (2.0 mM) butyrate concentrations exclusively induce increased activity levels of liver/bone/kidney ALP, low (0.5 mM) concentrations increase the activity of both, albeit induction of term-placental ALP is less pronounced. These observations indicate that the effect of butyrate on the two ALPs is non-coordinate and suggest that their expression by SW-620 cells is independently modulated.