Molecular analysis of melatonin-induced changes in breast cancer cells: microarray study of anti-cancer effect of melatonin

Melatonin is a pineal secretory product that acts as a chemical messenger for the dark/light cycle and plays a central role in synchronization of circadian rhythms. Melatonin has been reported to exhibit a variety of therapeutic effects, including antiaging, anti-oxidative, anti-inflammation, and anticancer (such as induction of tumor suppressor genes and suppression of the metabolism of tumor cells, including breast cancer cells). In this study, we investigated the genome-wide transcriptional responses of MCF-7 human breast cancer cells exposed to melatonin by microarray gene expression profiling. We identified 1,946 and 983 genes that were 2-fold up- or down-regulated within 72 h of 1 nM and 100 nM melatonin treatment. Gene Ontology (GO) enrichment analysis was performed for identification of the biological functions and biological processes affected by the differential expression of genes in melatonin-stimulated cells. The differentially expressed genes that were dysregulated in many biological functions included cell proliferation, immune responses, translation, cell adhesion, apoptosis, and cell cycle. Our findings support the view that melatonin-stimulated changes in gene expression contribute to the anticancer effect of melatonin in breast cancer cells.