Effect of gga-miR-155 on Cell Proliferation, Apoptosis and invasion of Marek’s disease Virus (MDV) transformed cell line MSB1 by targeting RORA

Abstract

Background Marek's disease (MD) is an avian lymphoproliferative neoplasm caused by the oncogenic Marek's disease virus (MDV). MicroRNAs (miRNAs) act as oncogenes or tumor suppressors in most cancers. The gga-miR-155 is downregulated in the MDV-infected chicken tissues or lymphocyte lines, although its exact role in tumorigenesis remains unclear. The aim of this study was to analyze the effects of gga-miR-155 on the proliferation, apoptosis and invasiveness of an MDV-transformed lymphocyte line MSB1 and elucidate the underlying mechanisms.Results The expression level of gga-miR-155 was manipulated in MSB1 cells using specific mimics and inhibitors. While overexpression of gga-miR-155 increased proliferation, decreased the proportion of G1 phase cells relative to that in S and G2 phases, reduced apoptosis rates and increased invasiveness. However, its downregulation had the opposite effects. Furthermore, gga-miR-155 directly targeted the RORA gene and downregulated its expression in the MSB1 cells.Conclusion The gga-miR-155 promotes the proliferation and invasiveness of the MDV-transformed lymphocyte line MSB1 and inhibits apoptosis by targeting the RORA gene.