Abstract 7300: Synergistic inhibition of prostate cancer growth by the combination of xanthohumol and ursolic acid

Abstract Within the United States, prostate cancer (PCa) is the most commonly diagnosed non-cutaneous cancer, and approximately 1 in 8 men will receive a diagnosis in their lifetime. As the second leading cause of cancer deaths in American men, about 1 in 41 will die because of prostate cancer. The World Health Organization has suggested that approximately one-third of all cancer deaths are preventable, and one of the suggested means of prevention is through the increased consumption of fruits and vegetables. Fruits and vegetables contain natural compounds known as phytochemicals which possess biological activity including some anti-cancer effects. By adapting the ATP-bioluminescence assay for cell viability, our laboratory screened a natural compound library to find combinations of these compounds that may synergistically inhibit PCa cell viability. One of the combinations to emerge from this screening process was xanthohumol (XAN) and ursolic acid (UA). We examined the ability of the combination to inhibit tumor growth in a mouse HMVP2 PCa allograft tumor model. Mice were fed diets supplemented with either XAN (0.2%) or UA (0.2%) alone or the combination. Mice on the combination diet showed a significant inhibition of HMVP2 PCa tumor growth compared to mice on the single-agent diets. In addition, in vitro studies were performed to support the allograft tumor study and to further examine the mechanism of action of the combination. A cell survival assay utilizing six different PCa cell lines indicated that the combination of XAN and UA synergistically inhibited the survival of all cell lines as calculated by the Bliss index. Mechanistic studies performed in PCa cells indicate that the combination of XAN and UA inhibits oncogenic signaling better than either agent alone. Additionally, unbiased metabolomics revealed that the tumors from mice fed the combination diet had significantly less S-adenosyl-L-methionine compared to all other groups. Overall, 13 metabolic pathways were significantly different in the tumors from mice fed the combination diet compared to all other groups. The current data suggest that using a combination of XAN and UA may be a valuable chemopreventive strategy for PCa in humans. Funding: This work was supported by NIH Grant CA228404. Citation Format: Rachel Clark, Achinto Saha, Chelsea A. Friedman, Ruggiero Gorgoglione, Stefano Tiziani, John DiGiovanni. Synergistic inhibition of prostate cancer growth by the combination of xanthohumol and ursolic acid [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7300.