Inhibition of epigallocatechin gallate-induced apoptosis by CoCl2 in human oral tumor cell lines
Ishino, A.; Kusama, K.; Watanabe, S.; Sakagami, H.
Anticancer Research 19(6b): 5197-5201
1999
ISSN/ISBN: 0250-7005 PMID: 10697534 Document Number: 510669
Epigallocatechin gallate (EGCG) induced apoptotic cell death in two human oral tumor cell lines (HSC-2, HSG), as judged by TUNEL method which detects DNA nick. Furthermore, the cytoplasm of EGCG-treated HSG cells was stained by M30 monoclonal antibody, which detects the degradation product of cytokeratin by activated caspase. The apoptosis-inducing activity of EGCG was significantly reduced by millimolar concentrations of CoCl2. CoCl2 also inhibited the cytotoxic activity of sodium ascorbate, gallic acid and curcumin, but not that of sodium-5, 6-benzylidene-L-ascorbate (SBA). This suggests that SBA, an antitumor agent, induces cell death by a different mechanism from that of other antioxidants used in this study. The possible role of CoCl2 for cell survival was discussed.