Effect of Interaction of Ni~(2+) and Green Tea Epigallocatechin Gallate on Tongue Carcinoma Cells

Ni2+ is the major ion release from nickel-based dental casting alloy and carcinogens.The major polyphenolic constituent present in green tea,(-)epigallocatechin-3-gallate(EGCG),shows chemoprevention on human cancer.The aim of this study was to determine the interaction between EGCG and Ni2+ and the biological effects on tongue squamous cell carcinoma.The interaction of EGCG and Ni2+ was analyzed by LC/MS.The cell viability was assessed by the MTT reduction assay.The results of LC/MS indicated that [EGCG-2Ni2+] and [EGCG-Ni2+] formed when EGCG and Ni2+ were added simultaneously.Ni2+ and EGCG both inhibited the proliferation of tongue carcinoma cells in a time-and dose-dependent manner.The cytotoxicity against tongue carcinoma cells was increased when EGCG and Ni2+ cotreated,and the inhibition effects were extremely dependent on the concentrations of EGCG and Ni2+,addition order and the ratio of [Ni2+] to [EGCG].