The effect of N-MYC downstream regulated gene-2 expression on epithelial to mesenchymal transition in thyroid cancer

Thyroid cancer is the most common endocrine malignancy. Epithelial- mesenchymal transition (EMT) is a process whereby epithelial cells lose epithelial characteristics and adopt mesenchymal characteristics. EMT is a necessary and an important step for beginning and progression in thyroid cancer like other epithelial-derived cancers. N-myc Downstream Regulated Gene-2 (NDRG2) which is a member of N-myc Downstream Regulated Gene (NDRG) family play roles in cell proliferation, differantiation and development. Studies showed that NDRG2 has tumor supressive functions and differentiation inducing roles. The aim of this study is to investigate the effects of NDRG2 expression on EMT in thyroid cancers. For this purpose, 8505C, BCPAP and FTC-133 cells were transfected with NDRG2 plasmid DNA while FTC-133 cells were transfected with NDRG2 siRNA for 48 hours. Transfection efficiency was evaluated with RT-PCR and western blot. Alterations in Snail, Slug, Twist1, Vimentin and E-cadherin expression levels were investigated with RT-PCR and western blot. Matrigel invasion, transwell migration, lateral migration, wound healing and adhesion assays were performed to evaluate metastatic cell behaviors after transfections. After NDRG2 plasmid DNA transfection, statistically significant decrease was observed in Vimentin protein expression in 8505C cells, invasive abilities and lateral migration of BCPAP cells. Additionaly, it was determined that NDRG2 overexpression in FTC-133 cells significantly reduced lateral migration and cell adhesion. NDRG2 siRNA transfection had no significant effect in the target gene and protein levels and metastatic cell behavior of FTC-133 cells. The data we obtained will contribute to the development of new approaches that will induce NDGR2 expression in order to prevent the progression of thyroid cancer.