title: Free Zn(2+) enhances inhibitory effects of EGCG on the growth of PC-3 cells.
abstract: 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.
authors.affiliation: Hua Jia Chi Campus, Zhejiang University, Hangzhou, P R China.
authors.forename: Shi-Li
authors.initials: SL
authors.lastname: Sun
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: He
authors.forename: Hai-Ning
authors.initials: HN
authors.lastname: Yu
authors.forename: Jun-Guo
authors.initials: JG
authors.lastname: Yang
authors.forename: Devajit
authors.initials: D
authors.lastname: Borthakur
authors.forename: Lan-Cui
authors.initials: LC
authors.lastname: Zhang
authors.forename: Sheng-Rong
authors.initials: SR
authors.lastname: Shen
authors.forename: Undurti N
authors.initials: UN
authors.lastname: Das
mesh_terms: 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*
chemical_list: D000975:Antioxidants; D011480:Protease Inhibitors; D002392:Catechin; C045651:epigallocatechin gallate; D015032:Zinc