Abstract B50: Evaluation of cancer preventive activity of Chinese medicinal formula Si-Wu-Tang

Abstract

Abstract Chemoprevention is one of the strategies for cancer control. Chinese herbal medicines provide a promising source toward developing low cost and low toxic chemopreventive agents. Si-Wu-Tang (SWT) is a traditional Chinese medicine that has been used in Asian countries for about 1,000 years for women's health. SWT contains four herbs: Rehmanniae, Angelica, Chuanxiong and Paeoniae. It also contains at least nine detectable compounds (Compounds 1 – 9). From our previous study, we found that in human breast cancer MCF-7 cells treated with SWT, the genes in the Nrf2 cytoprotective pathways were strongly induced (Wen et al, PLoS ONE, 2011), suggesting that SWT may have antioxidant and chemopreventive activity. To evaluate such activity, we used murine epidermal cell JB6-based soft agar transformation assay, which is a model extensively used to study tumor promotion and chemopreventive activity. JB6 cells were seeded in 96-well plates in 0.33% agar suspended on top of a layer of 0.5% agar. EGF (10 ng/mL) was used to promote the anchorage-independent growth of JB6 cells on soft agar, which is one of the hallmarks of cell transformation. Various concentrations of SWT, components and compounds were added together with EGF into the top and bottom layers of the agar. Colonies were counted 7 to 10 days after the treatment. SWT showed a dose-dependent inhibition of colony formation at non-toxic concentrations: 0.0256, 0.256 and 1.28 mg/mL inhibited 56.5, 79.6 and 93.2 % colony formation compared to the EGF only control, respectively. Each of the four individual herbal components of SWT showed certain degrees of inhibitory effects on colony formation at a high concentration (2.56 mg/mL). The most potent component is Paeoniae, which at 0.0256 and 0.256 mg/mL inhibited 58.5 and 85.3 % of colony formation, respectively. Five pure compound constitutes of SWT were also tested in the soft agar assay. Compound 3 at 2.0 and 10 ug/mL inhibited 73.91% and 99.33% of colony formation, respectively. Compound 5 at 4.0 and 10 ug/mL inhibited 83.95 and 96.99% of colony formation, respectively. Compound 8 at 0.2 and 4.0 ug/mL inhibited 93.98% and 99.67% of colony formation, respectively. The concentration range tested did not inhibit cell proliferation as measured by Sulforhodamine B assay, therefore the inhibition of cell transformation by these compounds was not caused by growth inhibition or the effects of cytotoxicity. Other compounds tested failed to show any effect on colony formation. In conclusion, this study demonstrates that SWT and its components were able to inhibit EGF-induced neoplastic transformation at non-toxic concentrations. This widely used Chinese medicinal formula may provide a promising option toward preventing many types of cancer. Citation Format: Mandy Mei Liu, Jeffery Fan, Zhijun Wang, Zhong Zuo, Moses Chow, Ying Huang. Evaluation of cancer preventive activity of Chinese medicinal formula Si-Wu-Tang. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr B50.