Lactophorin in Camel Milk Undergoing Specific Proteolysis and Exhibiting Potent Anticancer Action against Human Colon and Breast Cancer Cells Through ROS Generation

Abstract

Background: Camel milk has been recognized for its health benefits since ancient times and has recently been attracting increasing attention as a form of medical treatment for diverse human diseases. Studies on the health benefits of camel milk attributed its medicinal effects to nutritional status, but the molecular mechanisms of proteins involved in such effects remain unknown. Objectives: The aim of this study was to explore the anticancer properties of camel milk proteins (CMPs). Methods: CMPs were fractionated into camel casein proteins (CCPs) and camel whey proteins (CWPs). The CWP exhibited the most potent anticancer activity against colon (HCT-116) and breast (MCF-7) cancer cells. The CWP was further fractionated into cationic and anionic proteins using HiTrap cationic (SP-XL) and anionic (QFF) exchange columns. Results: QFF-bound proteins (QFF-B) exhibited the strongest anticancer activities against both cancer cells. QFF-B proteins produced three peaks (P1~P3) on RP-HPLC, whereas P3 showed superior anticancer activity. The cytotoxic effects of CWP and QFF-B proteins are associated with increased production of intracellular ROS and subsequent apoptosis in both cancer cells. MALDI-TOF-MS identified lactophorin, glycation-dependent cell adhesion molecule1 (GlyCAM-1), and its three driven fragments as dominant peptides in QFF-B, while RP-HPLC-P3 contained two of them with molecular masses of 8080.3 and 9395.6 Da. The two peptides, both derived from the C-terminal of lactophorin, were the most representative peptides in the most active protein fractions (QFF-B and RP-HPLC-P3). Conclusion: The results highlight for the first time that lactophorin is the major anti-cancer ingredient in camel milk and its unique C-terminal peptides present potential candidacy as anticancer agents in nutraceutical and pharmacological applications.