Experimental Research Of Ror2 Regulating Tumor Cell Migration

Approximately 90% of all cancer patients die from the metastatic spread of primary tumors. An understanding of the process by which cells from a localized tumor invade adjacent tissues and migrate to distant organs is crucial to anticancer strategies. A central aim in cancer therapy is to understand the mechanism of tumor cell migration.Receptor tyrosine kinases (RTKs) play crucial roles in developmental morphogenesis by regulating cellular proliferation,differentiation,migration,and death. The Ror-family receptors are orphan RTKs, which are evolutionarily conserved.Two structurally related Ror-family RTKs are found in mammals(Rorl and Ror2).Ror2 plays an important role in the nervous system and acral development. Previous studies showed Ror2 can interact with Wnt5a and CKIε, regulating canonical or non-canonical Wnt signaling pathway.However the relationship between Ror2 and tumor cell migration remains unclear.Our previous study showed that Ror2 was highly expressed in metastatic melanoma B16-BL6 cells but not in its lowly metastatic parental cell line,B16 cells.We propose that Ror2 may plays an important role in regulating tumor cell invasion and migration.In this paper, using a recombinant adenovirus, we investigate the effect of human Ror2 gene over-expression and RNAi on tumor cell migration both in vitro and in vivo. Our results show:First, by the way of homologous recombination in eukaryotic cells, we constru cted a recombinant adenovirus Ad-Ror2-Flag that could express human Ror2 effectively. We also got a recombinant adenovirus AdH1-Ror2-RNAi,which could interfere the expression of Ror2 efficiently. The functions of the two adenovirus were examined via immunoblotting. Second, in vitro wound-healing assay indicated that the migratory ability of B16-BL6 cells was inhibited by infected with AdHl-Ror2-RNAi. When B16-BL6 cells were injected through the tail vein of C57BL/6J mice, B16-BL6 cells infected with AdHl-Ror2-RNAi formed much less metastatic tumors in lungs and livers of the mice than that in control groups.But hypodermic inoculation of B16-BL6 cells infected with AdH1-Ror2-RNAi showed no significant effect on tumor genesis or growth.All these results indicated that ,taking the way to knocking down the expression of Ror2 by RNA interference could markedly inhibit the migration of metastatic melanoma B16-BL6 cells in vitro and in vivo. The results suggest that Ror2 plays a key role in regulating tumor cell migration.