Expression of astrocyte elevated gene-1 (AEG-1) in human meningiomas and its roles in cell proliferation and survival.

Abstract

Astrocyte elevated gene-1 (AEG-1) has recently been proposed to be involved in tumor development, invasion, and metastasis in several human cancers. However, the functional importance of AEG-1 expression in human meningioma has not been determined. We investigate the level of AEG-1 expression by quantitative reverse transcription PCR, immunohistochemistry analysis, and western blotting in various human meningioma tissues and cells. To determine the suppressive effect of AEG-1 on meningioma progression, we inhibited AEG-1 expression using small interfering RNA and examined cell proliferation, apoptosis, colony formation and tumorigenicity in a mouse xenograft model. AEG-1 expression was frequently elevated at both mRNA and protein levels in meningioma tumor tissues and in meningioma-derived cells as well. This elevation was more commonly observed in high-grade tumors than in benign ones. The knockdown of AEG-1 led to a decrease in overall cell proliferation, as well as anchorage-independent growth of malignant meningioma. In addition, apoptotic cell death occurred in AEG-1 depleted meningioma cells through p-Akt and Bcl-2 suppression. Furthermore, a mouse xenograft meningioma model showed that inhibition of AEG-1 expression significantly decreased tumor growth. Altogether, these data show that the elevation of AEG-1 contributes to the malignant progression of meningiomas, suggesting that AEG-1 could be a novel therapeutic target against human meningiomas.