Apoptosis in human leukemic cells induced by lactoferricin, a bovine milk protein-derived peptide: involvement of reactive oxygen species.

Abstract

We examined the activity of bovine lactoferricin (Lfcin-B), a peptide derived from a bovine milk protein lactoferrin (LF-B), to induce apoptosis in THP-1 human monocytic leukemic cells. Treatment with Lfcin-B at up to 50 micrograms/ml induced cell death in THP-1 cells in dose- and time-dependent manner, showing apparent morphological changes, hypodiploid forms of genomic DNA and apoptotic DNA fragmentation, whereas LF-B was inactive even at a high dose (500 micrograms/ml). The apoptosis-inducing effect of Lfcin-B increased with reduction of serum concentration, but was inhibited by addition of Zn2+, a inhibitor of Ca2+/Mg(2+)-dependent endonucleases in a dose-dependent manner. Furthermore, Lfcin-B-induced apoptosis in THP-1 cells was completely abolished by addition of antioxidants such as N-acetyl-L-cysteine (NAC) and glutathione (GSH), but not by various cytokines and mitogen which can activate monocytic cells. In addition, THP-1 cells treated with Lfcin-B, but not LF-B, showed high levels of intracellular reactive oxygen species (ROS) from the early period (20 min) of Lfcin-B treatment. And the production of ROS by Lfcin-B was dependent upon the dose of Lfcin-B added. These results suggested that Lfcin-B, a LF-B-derived peptide, but not LF-B itself, is able to induce apoptosis in THP-1 human monocytic tumor cells, and that its apoptosis-inducing activity is related to the pathway mediated by production of the intracellular ROS and activation of Ca2+/Mg(2+)-dependent endonucleases.

• Authors: Y C Yoo, R Watanabe, Y Koike, M Mitobe, K Shimazaki, S Watanabe, I Azuma
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 237 Issue 3 Pg. 624-8 (Aug 28 1997) ISSN: 0006-291X [Print] United States
• PMID: 9299415 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• DNA, Neoplasm
• Reactive Oxygen Species
• lactoferricin B
• Lactoferrin
• Glutathione
• Acetylcysteine

Topics

• Acetylcysteine (pharmacology)
• Animals
• Apoptosis (drug effects)
• Cattle
• DNA Fragmentation
• DNA, Neoplasm (drug effects)
• Diploidy
• Female
• Glutathione (pharmacology)
• Humans
• Kinetics
• Lactoferrin (analogs & derivatives, isolation & purification, pharmacology)
• Leukemia, Monocytic, Acute
• Milk (chemistry)
• Reactive Oxygen Species (metabolism)
• Tumor Cells, Cultured