Inhibition of glioma angiogenesis and invasion by anti-microtubule agent in a rat brain tumor model.

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We mainly achieved the following two investigations.(1)OBJECTIVE : We aimed to analyze the anti-invasive effect of the anti-matrix metalloproteinase (anti-MMP) agent SI-27 by quantitative tracking of enhanced green fluorescent protein(EGFP)-labeled human malignant glioma cell lines in a brain slice model. METHODS : Persistent expression of EGFP in human malignant glioma cell clones (U87MG, U251MG, and U373MG) was established with the use of the pEGFP-C1 vector. Tumor spheroid in 1 microl Matrigel was implanted into the caudate nucleus-putamen of a severe combined immunodeficient mouse brain slice. To allow the quantitative assessment of tumor cell invasion, the invasion area index was measured on Days 1,3,5,and 7 with a fluorescence stereomicroscope and an image analyzer in the presence of various concentrations of SI-27(0,1,10,50,or 100 microg/ml). RESULTS : In the control group (0 microg/ml), all glioma cell lines invaded in a fingerlike fashion and reached the contralateral hemisphe … More re through the corpus callosum. SI-27 at concentrations of 10,50,and 100 microg/ml significantly suppressed the invasion area index on Days 5 and 7 in a dose-dependent manner, whereas 1 microg/ml had no effect. Transmission electron microscopy and laser confocal microscopy indicated that the tumor cells had penetrated the brain slice and that the normal structural integrity of the brain was maintained until Day 7. CONCLUSION : This model enabled unequivocal periodic tracking of individual invading tumor cells in normal brain. The significant suppression of glioma cell invasion by noncytotoxic concentrations of SI-27 indicates that anti-MMP treatment may represent an important future therapeutic strategy for malignant cerebral neoplasms.(2)OBJECTIVE : The matrix metalloproteinase(MMP) inhibitor SI-27 has undergone extensive development because of its effectiveness against glioma invasion and angiogenesis. However, previous studies have been performed in vitro. The present work investigates the potential of SI-27 to inhibit tumor invasion, slow angiogenesis, and prolong survival in rodent brain tumor models. METHODS: Stable enhanced green fluorescent protein-expressing clones of a human malignant glioma cell line, U251MG, were stereotactically xenografted into the periphery of the anterior striatum and corpus callosum of Fischer 944 rats after immunosuppression with cyclosporin A, SI-27(1 or 10 mg/kg) or carrier solution was administered on three successive days by intraperitoneal injection, and tumor invasion and angiogenesis were assessed 3 weeks later by quantitative image analysis. This was performed on whole brain sections analyzed either by direct observation of enhanced green fluorescent protein-expressing glioma cells or by additional immunohistochemistry to detect the endothelial cells with anti-factor VIII monoclonal antibody In situ zymography on frozen sections was used to detect MMP activity. RESULTS : The group receiving a total of 30 mg/kg showed a statistically significant (P<0.001) increase in survival time compared with the controls receiving carrier (median survival, 47.3 versus 32.6 d). There was also a decrease in MMP activity, tumor cell invasion, and neovascularization. In contrast, animals given 3 mg/kg did not show these differences. CONCLUSION : Systemic administration of the anti-MMP agent SI-27 is effective in the treatment of glioma in an animal model. Less