Role of type I- and type II-interferon in expression of melanoma differentiation-associated gene-5 in HSC-3 oral squamous carcinoma cells

Abstract

Melanoma differentiation-associated gene 5 (MDA-5) and retinoic acid-inducible gene-I (RIG-I)are members of DExH family of proteins, and known to play important roles in antiviral responsesto induce type I interferons (IFNs). MDA-5 has been thought to sense RNA virus with long(>1 kb) double-stranded RNA. However, MDA-5 is also induced by type II IFN that is involvedin acquired immunity, suggesting that role of MDA-5 remains to be elucidated. In addition, nostudy regarding MDA-5 in oral region has been performed. Here we investigated the role ofMDA-5 in HCS-3 squamous carcinoma cells derived from oral epithelial cells. Treatment of HCS-3 cells with IFN-α2b or IFN-γ significantly induced MDA-5 as well as RIG-I. IFN-α2b exertedanti-proliferative effect in HSC-3 cells while no such effect was observed in the cells treated withIFN-γ. MDA-5 is known to be associated with tumor cell growth in melanoma. However, overexpressionof MDA-5 did not alter the proliferation in HSC-3 cells, indicating that MDA-5 is unrelatedto the cell growth in this type of cells. We conclude that MDA-5 is induced by both typeI- and type II-IFNs in HSC-3 cells, and this suggests MDA-5 may play a role in immune responsesin oral cavity.