ABSTRACT
The receptor tyrosine kinase (RTK) Ror2 plays important roles in developmental morphogenesis and mediates the filopodia formation in Wnt5a-induced cell migration. However, the function of Ror2 in noncanonical Wnt signaling resulting in cancer metastasis is largely unknown. Here, we show that Ror2 expression is higher in the highly metastatic murine B16-BL6 melanoma cells than in the low metastatic variant B16 cells. Overexpression of Ror2 increases the metastasis ability of B16 cells, and knockdown of Ror2 reduces the migration ability of B16-BL6 cells. Furthermore, the inhibition of Src kinase activity is critical for the Ror2-mediated cell migration upon Wnt5a treatment. The C-terminus of Ror2, which is deleted in brachydactyly type B (BDB), is essential for the mutual interaction with the SH1 domain of Src. Intriguingly, the Neurotrophin receptor-interacting MAGE homologue (NRAGE), which, as we previously reported, can remodel the cellular skeleton and inhibit cell-cell adhesion and metastasis of melanoma and pancreatic cancer, sharply blocks the interaction between Src and Ror2 and inhibits Ror2-mediated B16 cell migration by decreasing the activity of Src and focal adhesion kinase (FAK). Our data show that Ror2 is a potential factor in the tumorigenesis and metastasis in a Src-dependent manner that is negatively regulated by NRAGE.
Subject(s)
Melanoma, Experimental/metabolism , Melanoma, Experimental/pathology , Neoplasm Proteins/metabolism , Receptor Tyrosine Kinase-like Orphan Receptors/metabolism , src-Family Kinases/metabolism , Adenoviridae , Animals , Blotting, Western , Cell Line, Tumor , Cell Movement/genetics , Focal Adhesion Kinase 1/metabolism , Gene Knockdown Techniques , Humans , Immunoprecipitation , Male , Melanoma, Experimental/genetics , Mice , Mice, Inbred C57BL , Neoplasm Metastasis , Receptor Tyrosine Kinase-like Orphan Receptors/biosynthesis , Receptor Tyrosine Kinase-like Orphan Receptors/genetics , Signal TransductionABSTRACT
We previously reported that human NRAGE could significantly alter the cellular skeleton and inhibit cell-cell adhesion, suggesting that human NRGAE play a potential role in cellular motility. Here, we report overexpression of human NRAGE in PANC-1 and B16-Bl6 cells could significantly suppress the metastasis of these cells in vitro and in vivo. Consistently, PANC-1 with stable silencing of NRAGE by RNA interference, exhibits a more metastatic phenotype than the native cell. Expression of epithelial proteins, including E-cadherin and beta-catenin is down regulated in siRNA-NRAGE PANC-1 cells. Further studies find that overexpression of human NRAGE suppresses the mRNA expression and activity of MMP2 significantly. Summary, our studies indicate for the first time that NRAGE could suppress metastasis of melanoma and pancreatic cancer probably through downregulation of MMP-2.
