EXPRESSION OF FATTY ACYL-COA-BINDING PROTEINS IN COLON CELLS - RESPONSE TO BUTYRATE AND TRANSFORMATION

Fatty acyl-CoA affect many cellular functions as well as serving as ce llular building blocks. Several families of cytosolic fatty acyl-CoA b inding proteins may modulate the activities of fatty acyl-CoA. Intesti nal enterocytes contain at least three unique families of cytosolic pr oteins that bind fatty acyl-CoA: acyl-CoA binding protein (ACBP), fatt y acid binding proteins (including the liver, L-FABP and intestinal, l -FABP), and sterol carrier protein-2 (SCP-2). Immortalized rat colon e pithelial cell lines expressed only ACBP and SCP-2 at levels of 0.75 /- 0.13 and 0.42 +/- 0.02 ng/mu g protein. Ras and src transformation increased colon cell density and differentially altered ACBP and SCP-2 expression without affecting l-FABP or L-FABP levels. ACBP levels wer e 1.8-fold and 1.5-fold increased in ras- and src-transformed cells, r espectively. In contrast, SCP-2 expression was significantly decreased 55 and 67% in ras- and src-transformed cells, respectively. Butyrate treatment of ras- and src-transformed cells decreased cell proliferati on up to 60-85% as compared to 25-30% in control cells. Butyrate treat ment decreased ACBP expression in all cell lines but had no effect on the levels of SCP-2, l-FABP, or L-FABP. These studies suggest that the differential expression of ACBP and SCP-2 in rat colonic cell lines, as well as their modulation by butyrate, may be altered by cell transf ormation.