Induction of apoptosis by epigallocatechin-3-gallate via mitochondrial signal transduction pathway.
OBJECTIVE
To elucidate the apoptosis induction of Epigallocatechin-3-gallate (EGCG) on nasopharyngeal carcinoma (NPC) cells via mitochondrial signal transduction pathway regulated by EB-virus-encoded latent membrane protein 1 (LMP1).


METHODS
The survival rates of pTet-on-LMP1 HNE2 cells after the EGCG treatment were determined by MTT assay. Induction of apoptosis in pTet-on-LMP1 HNE2 cells after the EGCG treatment was analyzed by agarose gel electrophoresis. The activity of caspase-9 was determined by ApoAlert Caspase-9 Fluorescent Assay kit after the EGCG treatment. The protein expressions of cytochrome c and Bcl-2 were analyzed by Western blotting after the EGCG treatment.


RESULTS
EGCG inhibited the survival rates of pTet-on-LMP1 HNE2 cells and induced apoptosis of pTet-on-LMP1 HNE2 cells. EGCG raised the activities of caspase-9, enhanced the releasing of cytochrome c from the mitochondria, and suppressed the protein expression of Bcl-2. These are the key targets on the mitochondrial signal transduction pathway in apoptosis.


CONCLUSIONS
EGCG inhibited the survival rate of NPC cells and induced apoptosis of NPC cells via the mitochondrial signal transduction pathway. This study suggests that the interference effect of EGCG on targets of the mitochondrial signal transduction pathway plays an important role in the anticancer function.
Zhao
Yan
Y
Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan, PR China. yan_68cn@yahoo.com
Yang
Li-Fang
LF
Ye
Mao
M
Gu
Huan-Hua
HH
Cao
Ya
Y
D016588:Anticarcinogenic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053453:Caspase 9; D020169:Caspases / Q000032:analysis; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects*
D016588:Anticarcinogenic Agents; D002392:Catechin; C045651:epigallocatechin gallate; C506433:CASP9 protein, human; D053453:Caspase 9; D020169:Caspases