Rab23 is overexpressed in human astrocytoma and promotes cell migration and invasion through regulation of Rac1

Rab23 overexpression has been implicated in several human cancers. However, its biological roles and molecular mechanism in astrocytoma have not been elucidated. The aim of this study is to explore clinical significance and biological roles of Rab23 in astrocytoma. We observed negative Rab23 staining in normal astrocytes and positive staining in 39 out of 86 (45 %) astrocytoma specimens using immunohistochemistry. The positive rate of Rab23 was higher in grades III and IV (56.5 %, 26/46) than grades I + II astrocytomas (32.5 %, 13/40, p < 0.05). Transfection of Rab23 plasmid was performed induced A172 cell proliferation, colony formation, invasion, and migration, while Rab23 depletion with siRNA reduced these abilities of U87 cells. In addition, we found that Rab23 transfection upregulated while its depletion reduced Rac1 activity. Treatment of transfected cells with a Rac1 inhibitor decreased Rac1 activity and invasion. In conclusion, Rab23 serves as an important oncoprotein in human astrocytoma by regulating cell invasion and migration through Rac1 activity.