Anti-invasive effect of an anti-matrix metalloproteinase agent in a murine brain slice model using the serial monitoring of green fluorescent protein-labeled glioma cells.
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 hemisphere 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.


CONCLUSIONS
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.
Yoshida
Daizo
D
Department of Neurosurgery, Nippon Medical School, Tokyo, Japan.
Watanabe
Kunihiro
K
Noha
Masahiro
M
Takahashi
Hiroshi
H
Teramoto
Akira
A
Sugisaki
Yuichi
Y
D000818:Animals; D001932:Brain Neoplasms / Q000473:pathology*; D002421:Caudate Nucleus / Q000473:pathology; D046508:Culture Techniques; D005910:Glioma / Q000473:pathology*; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins; D008297:Male; D061965:Matrix Metalloproteinase Inhibitors; D051379:Mice; D016513:Mice, SCID; D018613:Microscopy, Confocal; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009842:Oligopeptides / Q000494:pharmacology*; D011699:Putamen / Q000473:pathology; D014407:Tumor Cells, Cultured / Q000187:drug effects* / Q000473:pathology
D008164:Luminescent Proteins; D061965:Matrix Metalloproteinase Inhibitors; D009842:Oligopeptides; C421267:SI 27; D049452:Green Fluorescent Proteins