Sodium arsenite downregulates transcriptional activity of AP-1 and CRE binding proteins in IL-1beta-treated Caco-2 cells by increasing the expression of the transcriptional repressor CREMalpha.

In recent studies, sodium arsenite (SA) inhibited IL-6 production in cultured intestinal epithelial cells, at least in part by downregulating the activity of nuclear factor-kappaB (NF-kappaB). The influence of SA on the activity of other transcription factors regulating the interleukin-6 (IL-6) gene in enterocytes is not known. We tested the effect of SA on the activity of CCAAT/enhancer binding protein (C/EBP), activating protein-1 (AP-1), and CRE binding proteins in IL-1beta-treated Caco-2 cells.