Malignant mesothelioma is an
asbestos-related fatal disease with no effective cure. We studied whether a
green tea polyphenol, epigallocathechin-3-gallate (EGCG), could induce cell death in five human
mesothelioma cell lines. We found that EGCG induced apoptosis in all five
mesothelioma cell lines in a dose-dependent manner. We further clarified the cell killing mechanism. EGCG induced
reactive oxygen species (ROS), and impaired the mitochondrial membrane potential. As treatment with ROS scavengers,
catalase and
tempol, significantly inhibited the EGCG-induced apoptosis, ROS is considered to be responsible for the EGCG-induced apoptosis. Further, we found that EGCG induced autophagy, and that when autophagy was suppressed by
chloroquine, the EGCG-induced cell death was enhanced. Taken together, these results suggest that EGCG has a great potential for the treatment of
mesothelioma by inducing apoptosis and autophagy.