Abstract: Background and purpose: Nir1 is a transmembrane receptor for chemokine (C-C motif) ligand 18. CCL18 specifically binds to Nir1 at the cellular membrane of breast cancer cells to exert its invasion and metastasis. However, the specific mechanism of Nir1 is not clear in glioma. This study probed the effect and mechanism of Nir1 in the invasion of glioma cells. Methods: Western blot was used to detect the expression of Nir1 in glioma cells. siRNA plasmid was used to transfect U251 cells. Western blot was used to analyze the expression of Nir1 and protein phosphorylation of Akt in the cells transfected by Nir1 plasmid. In vitro Matrigel invasion assay was used to detect the invasive ability in the cells that were transfected. F-actin polymerization assay was used to detect F-actin recognition ability in cells. Results: The expression of Nir1 was higher in all glioma cells. After transfection, the invasion of siNir1/ U251 was obviously decreased than the SCR/U251, F-actin content was reduced compared to the control group. Akt phosphorylation experiment result showed that the protein phosphorylation of Akt was enhanced in control group cells CCL18 following stimulation. However, the existence of CCL18 would affect the phosphorylation of Akt in siNir1/U251. Conclusion: Nir1 is high expression in glioma cells, and Nir1 binding to chemokine CCL18 promotes glioma cells invasion and metastasis through regulation the phosphorylation of Akt and F-actin polymerization .

Key words: Glioma, Nir1, Akt, Invasion, siRNA