Abstract
Members of the nuclear factor of activated T cells (NFAT) family have been identified as regulators of oncogenic transformation in several human malignancies. A prominent member of this family, NFAT1, is associated with tumor cell survival, apoptosis, migration and invasion. Here, we investigated the role of NFAT1 in glioma cells. In 111 clinical samples, microarray analysis demonstrated that NFAT1 was over-expressed in glioblastoma multiforme (GBM), compared with low-grade gliomas, a result confirmed by RT-PCR in 24 clinical samples and in the U87 and U251 cell lines. Immunohistochemistry and immunofluorescence stain indicated that over-expressed NFAT1 was mainly located in the nucleus, where it acted as a transcription factor. After treatment with the NFAT antagonist cyclosporin A (CsA) and FK506, levels of NFAT1 in the nuclei of U87 GBM cells were dramatically reduced. The invasive potential of U87 cells was reduced by the same treatment, as well as by inhibition of NFAT1 expression using small hairpin RNA. Proliferation of U87 cells was unaffected by CsA, FK506 and NFAT1 shRNA transfection. Clustering analysis and Pearson correlation analysis of microarray data showed that the expression of NFAT1 correlated with the expression of the invasion-related genes cyclooxygenase-2 (COX-2), matrix metalloproteinase-7 (MMP-7) and MMP-9, a result confirmed by in vitro analysis. These findings demonstrate that NFAT1 contributes to the invasive potential but not the proliferation of GBM cells, and suggest that CsA may find application as an adjuvant in combined treatment strategies for GBM.
Highlights
Glioma is the most common primary brain tumor and glioblastoma multiforme (GBM) is the most aggressive type of glioma [1]
Overexpressed NFAT1 is Activated in GBMs and Repressible by cyclosporin A (CsA) and FK506
In 50 clinical samples (25P and 25A), immunohistochemistry stain showed that NFAT1 protein was overexpressed and mainly located in the nuclei in GBM cells (23/25), while in astrocytomas NFAT1 was expressed at a low level and confined to the cytoplasm (6/25) (Fig. 1C)
Summary
Glioma is the most common primary brain tumor and glioblastoma multiforme (GBM) is the most aggressive type of glioma [1]. Chemotherapy and radiation, GBM quickly invades healthy brain tissue, with a median survival time of about 14 months [2], and the highly invasive nature of GBM cells is thought to contribute to the poor prognosis of this tumor. Many factors are involved in the migration and invasion of malignant tumors [3,4,5,6,7,8], of which NFATs are of special interest since they play key roles in the activation and differentiation of T cells. We demonstrated that NFAT1 is involved in overexpression of interleukin-13 receptor alpha subunit (IL13Ra2) in GBM [9]. We show for the first time that NFAT1 is overexpressed and activated in GBM, and that NFAT1 contributes to the invasion but not proliferation of GBM. We demonstrate that the effects of NFAT1 may be mediated by induction of cyclooxygenase-2 (COX-2), matrix metalloproteinase-7 (MMP-7) and MMP-9 expression
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
