Synovial sarcoma (SS) is a soft tissue sarcoma with poor prognosis and lack of response to conventional cytotoxic chemotherapy. The regulatory mechanisms for the rapid proliferation of synovial sarcoma poorly understood. Surgical resection with/without adjuvant radiotherapy and chemotherapy are the mainstay of treatment. Although the sarcoma cell lines have moderate chemosensitivity to isofamide and doxorubicin therapy, the overall prognosis is still poor. Therefore, further development of the treatment for SS is required. Kava is an ancient crop of the western Pacific. The root extract of kava has been served as a traditional beverage for Pacific Islanders. Consumption of this traditional beverage has been thought to be correlated with low and uncustomary sex ratios of cancer incidence in 3 kava-drinking countrites: Fiji, Vanuatu and Western Samoa. We have already reported that a kind of fravokawains from kava extracts (FKA: flavokawein A) induced apoptosis against bladder cancer cells, and flavokawein B (FKB) was also significant effective in inhibiting the growth of prostate cancer cells. In this study, we examined the inhibitory proliferation effects of the FKB in synovial sarcoma growth and whether FKB modulates tumor apoptosis cascades in human synovial sarcoma cell lines. We treated 2 cell lines of synovial sarcoma (SYO-I, HS-SY-II) by different concentrations of FKB (0, 2.5, 5.0, 7.5 μg/μl) for 24 hours. From the results of real time PCR, depending on the concentrations of FKB in both cell lines, the expression of Survivin was found to be decreased, while those of DR5, Puma, and Bim were increased. These results indicated that FKB effectively induces apoptosis of the two cell lines depending on the concentration. In conclusion, our findings demonstrate that FKB is effective for growth inhibition of synovial sarcoma cell lines in vitro and suggest that FKB may be a new therapeutic option for patients with synovial sarcoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4241. doi:10.1158/1538-7445.AM2011-4241