Effects of lactoferrin and its peptides on proliferation of rat intestinal epithelial cell line, IEC-18, in the presence of epidermal growth factor.
The cell growth-stimulating activity of lactoferrin (LF) in combination with epidermal growth factor (EGF) was evaluated by using a rat intestinal epithelial cell line, IEC-18. LF was found to be more effective than EGF for inducing an increase in cell numbers when cultured for over 6 days using a medium containing 0.2% fetal calf serum (FCS), although the 3H-thymidine incorporation-stimulating activity of EGF was more potent than that of LF. A synergistic effect of LF and EGF was observed in both cell proliferation and DNA synthesis assays. The increase in cell numbers when stimulated with LF plus EGF corresponded to about 5 times that of the control. Iron was not required for manifestation of these effects of LF. On the other hand, iron-saturated transferrin (TF) had cell-growth-stimulating activity, but iron-free TF did not, either in the presence or absence of EGF. These results indicate that LF induces cell proliferation by a mechanism distinct from that of TF. A pepsin-generated hydrolysate of LF (LFH) had an activity similar to that of undigested LF, and a peptide with cell-growth-stimulating activity from bovine LFH was isolated by monitoring its effects in combination with EGF on DNA synthesis in IEC-18 cells. Sequence analysis indicated that the peptide has the structure Ala-Glu-Ile-Tyr-Gly-Thr-Lys-Glu-Ser-Pro-Gln-Thr-His-Tyr-Tyr, corresponding to residues 79-93 of bovine LF.
Hagiwara
T
T
Nutritional Science Laboratory, Morinaga Milk Industry Co., Ltd., Kanagawa, Japan.
Shinoda
I
I
Fukuwatari
Y
Y
Shimamura
S
S
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D006801:Humans; D006868:Hydrolysis; D007413:Intestinal Mucosa / Q000166:cytology; D007781:Lactoferrin / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D014168:Transferrin / Q000494:pharmacology
D010446:Peptide Fragments; D014168:Transferrin; D004815:Epidermal Growth Factor; D004247:DNA; D007781:Lactoferrin; D010434:Pepsin A