Flavokawain A Inhibits Urinary Bladder Cancer In Upii-Mutant Ha-Ras Transgenic Mouse Bladder Cancer Model

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Flavokawain A is the predominant chalcone identified from kava extract. We have recently shown that flavokawain A exhibited strong growth inhibitory effects on human bladder cancer cells both in vitro in cell cultures and in vivo in a xenograft mouse model. To examine whether flavokawain A affects specific-stages or course of bladder cancer development, the UPII-mutant Ha-ras transgenic mouse bladder model that mimics human papillary transitional cell carcinoma was used. The homozygous mutant Ha-ras transgenic mice were identified through genotyping using Southern blotting analysis and fed orally with 1g flavokawain A/kg food or 6 g flavokawain A /kg food for 3 or 6 months starting at 6 weeks of age. After treatments, organs are collected and weighted. H&E staining and immunohistochemstry were used to evaluate bladder cancer pathology and expression of biomarkers. All control food- fed male mice died of ureter obstruction and nephrohydrosis within 6 months of treatment, while more than 50% of mice fed with 6g flavokawain A /kg food for 6 months survived beyond the 6 months of treatment. The mean bladder weight in 6g flavokawain /kg food fed male mice also decreased by 66% compared to control treated mice for 3 months. Mouse pathology analysis showed that control mice exhibited poorly differentiated transitional cell carcinoma, while that flavokawain A treated mice presented well differentiated tumors. Compared to the dose of 6g/kg, a 1g/kg dose of flavokawain A is less effective in inhibition of bladder cancer development in this transgenic model. In addition, immunohistochemistry staining of Skp2 revealed that Skp2 oncoprotein expression in urothelium was also significantly decreased in flavorkawain A treatment group compared to control group. Taken together, our results suggest the potential usefulness of flavokawain A in treatment of superficial urinary bladder cancer. 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 855. doi:10.1158/1538-7445.AM2011-855