Antiproliferative and Apoptotic Effects of Zinc-Citrate Compound (CIZAR(R)) on Human Epithelial Ovarian Cancer Cell (OVCAR3)

Lee, Yong Seok; Kim, Jae Dong; Park, Lae Ok; Bae, Seog Nyeon

Abstract

OBJECTIVE
Human seminal plasma has diverse biological activities including cytotoxic effect. It contains high concentrations of zinc and citric acid. Zinc inhibits several carcinoma cell growths through induction of cell cycle arrest and apoptosis. We tried to investigate the effects of zinc-citrate compound (CIZAR(R)) on normal human ovarian epithelial (NOSE) cells and human epithelial ovarian cancer cells, OVCAR-3.
METHODS
To investigate the potential effect of CIZAR(R) on cell growth and survival, cells were treated with different dose and exposed to different time. Mitochondrial(m)-aconitase activity was determined in cell extracts using aconitase assay. The flow cytometric assay, DNA laddering, telomerase activity and morphological analysis were done to investigate apoptosis of OVCAR-3 cells. Molecular mechanism of apoptosis was investigated by p53, Bcl-XL, Bcl-2, Bax protein, and caspase activity.
RESULTS
Treatment of OVCAR-3 cells with CIZAR(R) resulted in a time- and dose-dependent decrease in cell number in comparison with NOSE cells. M-aconitase activity was significantly decreased in OVCAR-3 cells but relatively constant in NOSE cells. The flow cytometric assay, DNA laddering and morphological analysis indicated apoptosis of OVCAR-3 cells. CIZAR(R) did not affect p53 but increased the expression of p21waf1 upon the indicated times and induced reduction of telomerase activity. CIZAR(R) reduced expression of Bcl-2 and Bcl-xL proteins but induced expression of Bax protein. CIZAR(R) induced apoptosis of OVCAR-3 cells by activation of caspase-3 pathway.
CONCLUSION
These results show that CIZAR(R) prevent the proliferation of OVCAR-3 cells by inactivation of m-aconitase activity and induce apoptosis by induction of apoptotic genes and repression of antiapoptotic genes without adverse effect on normal ovarian epithelial cells. These results will offer new window in prevention and treatment of epithelial ovarian cancer.