Abstract 4221: Inhibition of hedgehog signaling by extracts of sutherlandia

Many botanical compounds that have been proposed to prevent cancer may potentially work via inhibition of the hedgehog-signaling pathway. Here we investigated the potential of Sutherlandia frutescens (also called “cancer bush” in South Africa) to prevent and/or treat prostate cancer. We hypothesize that the anti-cancer effects of Sutherlandia are due to its inhibition of hedgehog-signaling pathway activity. To determine hedgehog pathway inhibitory activity, we treated Shh light II cells with multiple doses of a methanol extraction of Sutherlandia and measured Gli1 reporter activities. Results: We found that a methanol extract of Sutherlandia was able to inhibit hedgehog pathway activity in a dose-dependent manner as monitored by Gli reporter assay (IC50=1:4000). Moreover, the Sutherlandia extract can inhibit the growth of human prostate cancer cells PC3 and LNCaP with IC50 of 1:400 and 1:1500 fold dilutions, respectively. At these same extract dilutions normal prostate cancer cell growth was not inhibited. Our data indicate that Sutherlandia contains potent anti-cancer botanicals that have hedgehog inhibitory activity. Conclusion: Our results suggest that this plant offers a potentially cheap and effective alternative for hedgehog-driven cancer therapies. Additionally, Sutherlandia may yield novel targets that potentially could lead to a second generation hedgehog inhibitor, as resistance has been found to the first generation drugs currently in clinical trials. 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 4221. doi:10.1158/1538-7445.AM2011-4221