[Epigallocatechin-3-gallate interferes with EBV-encoding AP-1 signal transduction pathway].
OBJECTIVE
To elucidate the interference effect of Epigallocatechin-3-Gallate (EGCG) on targets of Activator Protein-1 (AP-1) signal transduction pathway activated by EB virus encoded latent membrane protein 1 in nasopharyngeal carcinoma (NPC) cell lines.


METHODS
Survival rate of cells was determined by MTT assay. AP-1 and CyclinD1 activation were analyzed by promoter luciferase reporter system. Nuclear translocation of JNK was analyzed by indirect immunofluorescence. Protein expression and phosphorylation were observed by Western blot.


RESULTS
EGCG inhibited the survival of CNE1 and CNE-LMP1 cells and the activity of AP-1 caused by LMP1 in CNE-LMP1 cells. EGCG also inhibited the nuclear translocation of JNK and the phosphorylation of c-Jun. It also inhibited cyclinD1 promoter activity and cyclinD1 expression.


CONCLUSIONS
EGCG inhibits AP-1, JNK, c-Jun and cyclinD1 which are key targets on AP-1 signal transduction pathway. The results may explain the molecular mechanism of action of EGCG against nasopharyngeal carcinoma.
Zhao
Yan
Y
Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha 410078, China. yan_68cn@yahoo.com
Wang
Hai
H
Zhao
Xiao-rong
XR
Luo
Fei-jun
FJ
Tang
Min
M
Cao
Ya
Y
D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology / Q000821:virology; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004854:Herpesvirus 4, Human; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014763:Viral Matrix Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
C037662:EBV-associated membrane antigen, Epstein-Barr virus; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1; D014763:Viral Matrix Proteins; D002392:Catechin; C045651:epigallocatechin gallate; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases