Relation between retinoic acid-inducible gene-I expression and cell proliferation in human melanoma cells

Abstract

    Retinoic acid-inducible gene-I (RIG-I) is a cytoplasmic receptor recognizes the double stranded RNA derived from viruses, and activates antiviral responses such as the production of type 1 interferon (IFN). IFN-β (type 1 IFN) has been established as one of the treatments for malignant melanoma. This study investigated the effects of various cytokines, including IFN-β, on RIG-I expression and cell growth in human melanoma cells. IFN-β upregulated RIG-I expression in a number of human melanoma cell lines except for MeWo melanoma cells. The cellular proliferative potential of 501mel cells, which represented the IFN-β-induced RIG-I upregulation, was suppressed by IFN-β. However, MeWo cells under conditions of IFN-β stimulation showed neither RIG-I upregulation nor suppression of cell growth. Therefore, we introduced the RIG-I expression vector to MeWo cells and examined the cell growth. The result showed suppression of cell growth by IFN-β, indicating that RIG-I plays essential roles for the inhibition of the cellular proliferative potential by IFN-β. Thus, we revealed the existence of melanoma cells lacking the expression of RIG-I protein, and suggested that expression levels of RIG-I in melanoma tissues may determine how effect IFN-β treatment has on melanoma of these patients.