Abstract 1894: Cocoa tea ( Camellia ptilophylla ): another beverage for chemotherapy of prostate cancer

Prostate cancer (PCa) is the most common malignancy and the second leading cause of male death in USA and many European countries. It is therefore necessary to intensify our efforts to better understand this disease and develop novel approaches for its prevention and treatment. One approach to control PCa is its prevention through agents present in diet and beverages consumed by humans. Almost all supplements sold to the consumer with the promise of improving prostate health contain antioxidants. One such agent which has received much attention for prevention and treatment of PCa is green tea, whose effects are attributed to polyphenols present therein. Cocoa tea derived from the plant Camellia ptilophylla is a natural decaffeinated tea plant which grows in southern China. The local people have habitually drunk cocoa tea for a long time, not only as a healthy beverage but also as a traditional remedy for ailments. Herein, we provide evidence that cocoa tea also possesses strong antioxidant properties and could be useful for prevention and treatment of PCa. We extracted white cocoa tea, green cocoa tea and black cocoa tea with water and their extracts are referred to as WCT, GCT and BCT, respectively. Based on HPLC analysis, WCT and GCT were found to mainly contain four catechins including gallocatechin gallate, epigallocatechin gallate, catechin, gallocatechin and theobromine. No caffeine was detected in WCT, GCT and BCT. Besides, WCT contained more catechins than GCT and BCT. MTT assay showed that among the three extracts, WCT had the strongest inhibition of cell growth in PC-3 cells. Treatment of PC-3 cells with WCT (100-150 µg/ml, equivalent GCG 44-66 µM;72 h) inhibited cell proliferation which correlated with G2/M phase cell cycle arrest. Immunoblot analysis revealed that WCT treatment to PC3 cells resulted in, (i) induction of WAF1/p21 and KIP1/p27; (ii) decrease in cyclins D1, D2 and E; (iii) decrease in cyclin-dependent kinase (cdk) 2, 4 and 6; (iv) induction of Bax and downregulation of Bcl-2; (v) decrease in procaspase-3, −8; (vi) inhibition of nuclear translocation and phosphorylation of NF-κB, and activation of IKKα; (vii) inhibition of phosphorylation and degradation of IκBα. Next, athymic nude mice (6-8 weeks old) were implanted with PC-3 cells and divided into three groups. Treated group of animals received freshly prepared solution of 0.1% and 0.2% WCT in drinking water as the sole source of drinking fluid throughout the experiment. The animals were followed for tumor growth twice weekly. Compared to that in water fed mice, considerably slower tumor growth (P Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1894.