IRAN SATURATION ALTERS THE EFFECT OF LACTOFERRIN ON THE PROLIFERATIONAND DIFFERENTIATION OF HUMAN ENTEROCYTES (CACO-2 CELLS)

Recent studies have indicated that lactoferrin may act as a cell mitog en. The effect of human and bovine lactoferrins on the proliferation a nd differentiation of a human intestinal epithelial cell Line (Caco-2) was investigated and compared with that of human transferrin. Caco-2 cells were cultured in serum-free media supplemented with both iron-un saturated and -saturated forms of the iron-binding proteins. Cell prol iferation and differentiation were evaluated by examining growth curve s and measuring sucrase and alkaline phosphatase activities of brush b order membrane fractions, respectively. The iron-binding status of lac toferrins and transferrin affected the proliferation of Caco-2 cells. The iron-saturated forms of human (S-hLf), bovine (S-bLf) lactoferrins and human transferrin (S-hTf) enhanced cell proliferation, while iron -unsaturated forms (U-hLf, U-bLf, and U-hTf) suppressed it. Iron-bindi ng status also determined the effect oflactoferrin and transferrin on cellular differentiation, but this effect differed for different brush border enzymes, S-hTf enhanced sucrase activity more than S-hLF or S- bLf. Both U-hLf and U-bLf markedly suppressed sucrase activity. U-hTf suppressed alkaline phosphatase activity appreciably, while the other iron-binding proteins showed no significant effect on it, Lactoferrin and transferrin may modulate the proliferation and differentiation of intestinal epithelial cells, but their efficacy depends on their satur ation with iron.