Melatonin Inhibits Gastric Cancer Cell Proliferation by Suppressing Exosome miR-27b-3p Expression

Background/Aim: In addition to its established role in regulating circadian rhythms and reducing inflammation, melatonin has been demonstrated to possess anti-cancer properties. In this study, we investigated the effects of exosomal miRNAs released by melatonin-treated GC cells on gastric cancer. Materials and Methods: To identify the potential exosomal miRNAs involved in the treatment of gastric cancer, we performed exosome small RNA sequencing (sRNA-seq) to screen significant changes in 34 exosomal miRNAs in AGS cells before and after melatonin treatment. CCK-8, wound healing, and transwell invasion assays were used to examine the effects of miRNAs on cancer characteristics. Furthermore, a dual-luciferase reporter gene assay was performed to identify the miRNA targets. Results: Exosomal miR-27b-3p was down-regulated by approximately 1.37-fold following melatonin treatment. The CCK-8 assay revealed a significant increase in cell proliferation in the miR-27b-3p mimic group compared to that in the miR-27b-3p mimic NC group. In the wound healing assay, cells treated with miR-27b-3p mimics displayed significantly more rapid wound closure than that observed in the miR-27b-3p mimic NC group. The transwell invasion assay revealed a substantial increase in the number of invading cells in the miR-27b-3p mimic group compared to that in the miR-27b-3p mimic NC group. Additional analysis revealed that miR-27b-3p directly targets ADAMTS5 and that its up-regulation results in increased proliferation, invasion, and metastasis of GC cells. Conclusion: Melatonin suppressed the progression of gastric cancer by regulating the exosomal miR-27b-3p-ADAMTS5 pathway. Thus, melatonin represents a promising potential therapeutic agent for patients with gastric cancer.