Expression of vascular endothelial growth factor-A and mRNA stability factor HuR in human meningiomas

We studied the expression of vascular endothelial growth factor-A (VEGF-A) and mRNA stability factor HuR in 40 supratentorial meningiomas using RT-PCR, ELISA and immunohistochemistry, and analyzed their associations with the clinicopathological characteristics, including microvascular density (MVD), peritumoral brain edema (PTBE), histological subtypes and grades, and the performance of preoperative arterial embolization. Furthermore, we investigated the involvement of HuR in the upregulation of VEGF-A expression using primary meningioma cell cultures. The level of VEGF-A is elevated in meningiomas with PTBE and in higher grade meningiomas. Preoperative arterial embolization did not significantly increase the level of VEGF-A, but it did increase the expression of HuR in tumor tissues. HuR expression was correlated positively with VEGF-A expression in meningioma tissues. In in vitro experiments, hypoxia induced the upregulation of VEGF-A expression and the cytoplasmic translocation of HuR protein in meningioma cells, and inhibition of the cytoplasmic translocation of HuR reduced the upregulation of VEGF-A expression in meningioma cells. These findings suggest that the expression of VEGF-A relates to the development of PTBE with meningiomas and the histological grade, and that HuR is involved in the upregulation of VEGF-A expression in human meningiomas.