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Inhibitory
effect of epigallocatechin-gallate on brain tumor cell lines in vitro
Yokoyama S, Hirano H, Wakimaru N, Sarker KP, Kuratsu J
Department of Neurosurgery, Faculty of Medicine, Kagoshima
University, Japan
We investigated the effect of epigallocatechin-gallate (EGCG), the main
constituent of green tea polyphenols, on human glioblastoma cell lines U-373 MG
and U-87 MG, rat glioma cell line C6, and rat nonfunctioning pituitary adenoma
cell line MtT/E.
Cell viability was determined by assay with
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), and the
extent of apoptosis was studied by flow cytometric analysis.
Apoptosis was also characterized by morphology using fluorescent
microscopy.
The role of insulin-like growth factor-I (IGF-I) was studied by assay with MTT,
immunohistochemistry, and immunoradiometric assay.
After 72-h exposure, a statistically significant loss of viability (P = <
0.0001) was observed at concentrations of 12.5, 25, 50, and 100 microg/ml in
U-373 MG cells and U-87 MG cells.
EGCG at concentrations of 50 microg/ml and higher significantly reduced the
viability of C6 cells.
EGCG inhibited viability of MtT/E cells only at a concentration of 100
microg/ml.
Quantitative study by flow cytometry demonstrated that lower doses of EGCG
(12.5, 25, 50 microg/ml) induced apoptosis in U-373 MG, U-87 MG, and C6 cells;
however, only the highest dose (100 microg/ml) induced apoptosis in MtT/E
cells.
Compared with other cell lines, MtT/E cells showed stronger IGF-I
immunoreactivity.
Neutralization of IGF-I with an antihuman IGF-I antibody reduced viability of
the cell lines.
It can be concluded that EGCG has an inhibitory effect on malignant brain
tumors, and IGF-I may be involved in the effects of EGCG.
PMID: 11305413 [PubMed - indexed for MEDLINE]
Source: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11305413&dopt=Abstract
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