Spy1 Is Frequently Overexpressed in Malignant Gliomas and Critically Regulates the Proliferation of Glioma Cells

Spy1, a member of the Speedy/RINGO family, is a novel activator of cyclin-dependent kinases known to mediate cell cycle progression and cell survival in response to DNA damage. This study focused on the role of Spy1 in glioma oncogenesis. Immunohistochemistry and western blot analysis were performed to examine the expression of Spy1 in human glioma tissues and cell lines. Spy1 was frequently overexpressed in tumor tissues and cultured cells. Our data suggested that Spy1 expression positively correlated with the malignancy of gliomas. Altered expression of Spy1 led to changes in cell cycle processes, cyclin-dependent kinase 2 activity, and p27kip1 protein stabilization, ultimately disrupting cell growth rate. More importantly, high expression of Spy1 was associated with poor prognosis in patients with glioma, suggesting that Spy1 may be a novel independent prognostic predictor of survival for glioma patients. Collectively, this is the first report that Spy1 may play an essential role in the growth processes of human glioma.