Free Zn(2+) enhances inhibitory effects of EGCG on the growth of PC-3 cells.
Epigallocatechin-3-gallate (EGCG), a major component of green tea, has both preventive and therapeutic beneficial actions in prostate cancer. In the present study, we compared the growth inhibitory effects and the antioxidant and ability to modify cell membrane permeation of zinc-EGCG complex and Zn2+/EGCG mixture on androgen-insensitive prostate cancer (PC-3) cells. It was noted that free Zn2+ enhanced the growth inhibitory effects of EGCG on PC-3 cells at 160 micromol/L concentration,whereas zinc-EGCG complex was ineffective. EGCG showed potent free radical scavenging ability in the presence of Zn2+. EGCG in the presence of Zn2+ was more effective than EGCG alone in enhancing the permeability of the cell membrane, whereas zinc-EGCG complex had no effect on PC-3 cell membrane permeability. These results indicate that though Zn2+ enhanced the action of EGCG on PC-3 cells, zinc-EGCG complex is highly unlikely to be formed in the presence of Zn2+ and EGCG to explain the potentiating action of Zn2+ on the growth inhibitory property of EGCG on PC-3 cells.
Sun
Shi-Li
SL
Hua Jia Chi Campus, Zhejiang University, Hangzhou, P R China.
He
Guo-Qing
GQ
Yu
Hai-Ning
HN
Yang
Jun-Guo
JG
Borthakur
Devajit
D
Zhang
Lan-Cui
LC
Shen
Sheng-Rong
SR
Das
Undurti N
UN
D000975:Antioxidants / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000473:pathology*; D011480:Protease Inhibitors / Q000494:pharmacology; D015032:Zinc / Q000494:pharmacology*
D000975:Antioxidants; D011480:Protease Inhibitors; D002392:Catechin; C045651:epigallocatechin gallate; D015032:Zinc