Caco-2 cells and human fetal colon: a comparative analysis of their lipid transport

Caco-2 cells and human colonic explants were compared for their ability to esterify lipid classes? synthesize apolipoproteins and assemble lipoprotein s. Highly differentiated cells and colonic explants were incubated with [C- 14]oleic acid or [S-35]methionine for 48 h. Caco-2 cells demonstrated a hig her ability to incorporate [C-14]oleic acid into cellular phospholipids (13 -fold, P < 0.005), triglycerides (28-fold, P < 0.005) and cholesteryl eater (2-fold, P < 0.01). However, their medium/cell lipid ratio was II times lo wer, indicating a limited capacity to export newly synthesized lipids. De n ovo synthesis of apo B-48 and apo B-100 was markedly increased (7%0 and 240 %, respectively), whereas the biogenesis of apo A-I was decreased (60%) in Caco-2, cells. The calculated apo B-48/apo B-100 ratio was substantially di minished (107%), suggesting less efficient mRNA editing in Caco-2 cells. Wh en lipoprotein distribution was examined, it displayed a prevalence of VLDL and LDL, accompanied along with a lower proportion of chylomicron and HDL. In addition, differences in lipoprotein composition were evidenced between colonic explants and Caco-2 cells. Therefore, our findings stress the vari ance in the magnitude of lipid, apolipoprotein and lipoprotein synthesis an d secretion between the two intestinal models. This may be due to various f actors, including the origin of Caco-2 cell line, i.e., colon carcinoma. (C ) 1999 Elsevier Science B.V. All rights reserved.