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J Dairy Sci. 2012 Oct;95(10):5552-60. doi: 10.3168/jds.2011-5279. Epub 2012 Aug 15.

Reduction of ultraviolet light-induced DNA damage in human colon cancer cells treated with a lactoferrin-derived peptide.

Author information

1
Department of Food Technology, Engineering and Nutrition, Lund University, PO Box 124, 22100 Lund, Sweden.

Abstract

Treatment of Caco-2 cells with the peptide lactoferricin(4-14), results in reduction of the growth rate by prolongation of the S phase of the cell cycle. Lactoferricin(1-25) is formed in the gut by cleavage from lactoferrin and the bioactive amino acids are found within lactoferricin(4-14). Our hypothesis is that the reduction of the rate of S phase progression may result in increased DNA repair. To test this hypothesis, Caco-2 cells were subjected to UV light that caused DNA lesions and then the cells were grown in the absence or presence of 2.0 μM lactoferricin(4-14). Evaluation of DNA strand breaks using the comet assay showed that lactoferricin(4-14) treatment indeed resulted in a reduction of comets showing damaged DNA. In the search for a mechanism, we have investigated the levels of several proteins involved in cell cycle regulation, DNA replication, and apoptosis using Western blot. Lactoferricin(4-14) treatment resulted in an increased expression of flap endonuclease-1 pointing to increased DNA synthesis activity. Lactoferricin(4-14) treatment decreased the expression of the proapoptotic protein B-cell lymphoma 2-associated X protein (or Bax), indicating decreased cell death. As we have found previously, lactoferricin(4-14) treatment reduced the expression of cyclin E involved in the G(1)/S transition. Immunofluorescence microscopy showed that a lower γ-H2AX expression in lactoferricin(4-14)-treated cells, pointing to more efficient DNA repair. Thus, altogether our data show that lactoferricin(4-14) treatment has beneficial effects.

PMID:
22901475
DOI:
10.3168/jds.2011-5279
[Indexed for MEDLINE]

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