Selumetinib Inhibits Melanoma Metastasis to Mouse Liver via Suppression of EMT-targeted Genes

AIM: We investigated the therapeutic effects of a mitogen-activated protein (MEK) inhibitor, selumetinib, in a hepatic melanoma metastasis model and studied its possible mechanism of action. MATERIALS AND METHODS: Melanoma cell lines were exposed to selumetinib under different experimental conditions. We established a mouse model of liver metastasis and treated mice orally with vehicle or selumetinib and then evaluated metastasis progress. RESULTS: Growth inhibition was observed in melanoma cells as a consequence of G1-phase cell-cycle arrest and the subsequent induction of apoptosis in a dose- and time-dependent manner. Mice with established liver metastases that were treated with selumetinib exhibited significantly less tumor progression than vehicle-treated mice. c-Myc expression in metastasized liver tissues were suppressed by selumetinib. Moreover, oral treatment with selumetinib modulated expression of epithelial-to-mesenchymal transition- and metastasis-related genes, including integrin alpha-5 (ITGA5), jagged 1 (JAG1), zinc finger E-box-binding homeobox 1 (ZEB1), NOTCH, and serpin peptidase inhibitor clade E (SERPINE1). CONCLUSION: We established a mouse model of hepatic metastasis using a human melanoma cell line, such models are essential in elucidating the therapeutic effects of anti-metastatic drugs. Our data suggest the possibility that selumetinib presents a new strategy to treat liver metastasis in patients with melanoma by suppressing epithelial-to-mesenchymal transition-related genes.