Reduction of ultraviolet light-induced DNA damage in human colon cancer cells treated with a lactoferrin-derived peptide.
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.
Department of Food Technology, Engineering and Nutrition, Lund University, PO Box 124, 22100 Lund, Sweden.
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Freiburghaus
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Lindmark-Månsson
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Paulsson
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Oredsson
D000970:Antineoplastic Agents / Q000494:pharmacology*; D015153:Blotting, Western; D018938:Caco-2 Cells / Q000187:drug effects*; D045744:Cell Line, Tumor; D020552:Comet Assay / Q000379:methods; D004249:DNA Damage / Q000187:drug effects*; D004260:DNA Repair / Q000187:drug effects; D006801:Humans; D007781:Lactoferrin / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D016196:S Phase / Q000187:drug effects; D014466:Ultraviolet Rays / Q000009:adverse effects
D000970:Antineoplastic Agents; D010446:Peptide Fragments; C579774:lactoferricin 4-14, human; C082171:lactoferricin B; D007781:Lactoferrin