The value and correlation between PRL‐3 expression and matrix metalloproteinase activity and expression in human gliomas

Local invasion of tumor cells is characteristic of most human glioma invasions. It is associated with increased motility and a potential to degrade the extracellular matrix. Matrix metalloproteinases (MMPs) have been proved to be a main process in local invasion of brain tumor. PRL-3 is a new protein tyrosine phosphatase which would also degrade the extracellular matrix and has been proved to be expressed in liver metastases derived from colorectal cancer. In this study, we sought to investigate the expression of PRL-3 in glioma tissues and investigate the relationship between MMPs (MMP2, MMP9, membrane-type matrix metalloproteinase 1 [MT1-MMP]) activity and expression in gliomas. The modifications of in situ hybridization of mRNA phosphatase of regenerating liver-3 (PRL-3) methods are preformed in the study of paraffin-embedded slides. The immunohistochemistry and gelatin zymography are used to detect the expression of PRL-3 and activity of MMPs. The results show that PRL-3 mRNA and antibody of PRL-3 are detected in glioma tissues mainly in grades IV and III, only a little in grade II, but not in normal brain tissue and glioma grade I. MMP2 and MMP9 are observed mainly in glioma tissues of grades IV and III in activity and expression. MT1-MMP protein is located in glioma tissues and vessel endothelial cells. This is the first report of detecting PRL-3 expression in gliomas, especially in grades III and IV, which may play an important role in progression of gliomas. PRL-3, MMP2 and MT1-MMP cooperatively contribute to gliomas invasion. Intermediate MMP2 (MT1-MMP, TIMP-2, MMP2 trimeric complex) is detected in high grades of glioma tissues by gelatin zymography and may be a marker indicating latent malignance of gliomas.