請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/62082
標題: Involvement of p38 MAPK and Nrf2 in phenolic acid-induced P-form phenol sulfotransferase expression in human hepatoma HepG(2) cells
作者: Yeh, C.T.
顏國欽
Yen, G.C.
關鍵字: antioxidant response element
drug-metabolizing-enzymes
tert-butyl
hydroperoxide
green tea polyphenols
gene-expression
oxidative stress
cytosolic sulfotransferases
chemopreventive mechanisms
aryl
sulfotransferase
detoxication enzymes
期刊/報告no:: Carcinogenesis, Volume 27, Issue 5, Page(s) 1008-1017.
摘要: Phenolic acids have significant biological and pharmacological properties and some have demonstrated remarkable ability to alter sulfate conjugation. However, the modulation mechanisms of phenolic acids on phenol sulfotransferase expression have not been described. In the present study, we investigated the effects of phenolic acids on the expression of the Phase II P-form of phenol sulfotransferase (PST-P) in human hepatoma HepG(2) cells. RT-PCR and western blot data revealed that gallic acid induced increase in PST-P expression at the mRNA and protein levels, respectively. This induction was also marked by an increase in PST-P activity. Actinomycin D and cycloheximide inhibited gallic acid-responsive PST-P mRNA expression, indicating that gallic acid is a requirement for transcription and de novo protein synthesis. Transient transfection of HepG(2) cells with a reporter plasmid of the upstream region of the human PST gene caused a significant increase in reporter gene activity after gallic acid exposure. Moreover, gallic acid increased the nuclear levels of Nrf2, a transcription factor governing antioxidant response element (ARE). Electrophoretic mobility shift assay showed increased binding of nuclear proteins to ARE consensus sequence after treatment with gallic acid. While investigating the signaling pathways responsible for PST-P induction, we observed that gallic acid activated the p38 mitogen-activated protein kinase (MAPK) pathway. SB203580, a specific inhibitor of p38 MAPK, abolished gallic acid-induced PST-P protein expression. Similarly, gallic acid also caused an accumulation of Nrf2. Moreover, the protective effects of gallic acid on tert-butyl hydroperoxide-induced toxicity was partially blocked by p38 MAPK and PST-P inhibitors, further demonstrating that gallic acid attenuates oxidative stress through a pathway that involves p38 MAPK and PST-P. These results indicate that gallic acid is a potent inducer of PST-P and that PST-P induction is responsible for the gallic acid-mediated cytoprotection against oxidative damage.
URI: http://hdl.handle.net/11455/62082
ISSN: 0143-3334
文章連結: http://dx.doi.org/10.1093/carcin/bgi.281
顯示於類別:食品暨應用生物科技學系

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