The Combination of Two Bioactive Constituents, Lactoferrin and Linolenic Acid, Inhibits Mouse Xenograft Esophageal Tumor Growth by Downregulating Lithocholyltaurine and Inhibiting the JAK2/STAT3-Related Pathway

The addition of lactoferrin and three unsaturated fatty acids, oleic acid, docosahexaenoic acid (DHA), and linolenic acid, to dairy products was approved in recent years. Research into the biological activities of lactoferrin and these three unsaturated fatty acids has revealed anti-inflammatory, antiviral, antioxidant, antitumor, antiparasitic, and antibiotic effects. However, investigations and comparisons of lactoferrin + oleic acid/DHA/linolenic acid combinations in an esophageal cancer cell model and in xenograft tumor models have not been extensively reported, and the related mechanism of these combinations remains elusive. In the present study, the effects of lactoferrin and the three fatty acids on KYSE450 cell viability, migration, and invasion were investigated to choose the proper doses and effective combination in vitro. A tumor-bearing nude mouse model was established to investigate the role of selected combinations in inhibiting esophageal tumor formation in vivo. Metabonomics detection and data analysis were performed to screen special metabolites and related pathways, which were validated by western blotting. The results demonstrated that lactoferrin, the three unsaturated fatty acids, and their combinations inhibited the viability, migration, and invasion of KYSE450 cells and induced apoptosis and the lactoferrin + linolenic acid combination exhibited the strongest activity in suppressing KYSE450 tumor formation in vivo. The lactoferrin + linolenic acid combination inhibited phosphorylation in the JAK2/STAT3-related pathway by downregulating the special metabolite lithocholyltaurine, thereby suppressing formation of KYSE450 tumors.