Abstract 4214: Resveratrol: Effect on polyamine metabolism and synergistic interactions with DFMO and DenSpm in breast cancer and uveal melanoma cell lines

Abstract

Abstract Resveratrol, (3,5,4’-trihydroxy-trans-stilbene), was first reported to act as a chemo-preventative anticancer compound in mice by Jang et al. in 1997. It was subsequently shown to inhibit the growth and initiation of cancer cells in vitro and tumorigenesis in mouse cancer models. Recent work has focused on the role of the mitochondria in the resveratrol-induced death of the cancer cells, with resveratrol promoting apoptosis in both cancer cell lines and human tumors growing in host mice. In a colon cancer cell line (Caco), resveratrol has also been shown to affect the metabolism of polyamines, a group of compounds essential for the growth and proliferation of cells. Perturbations of polyamine levels and enzymes involved in their metabolism have long been targets of potential anti-cancer treatments. Difluormethylornithine (DFMO), a suicide inhibitor of ODC (the rate limiting biosynthetic enzyme), and N1, N11-diethylnorspermine (DenSpm), a polyamine analog leading to the induction of the polyamine catabolic enzyme SSAT, have been shown to reduce growth of cancer cells in several models and have been tested in clinical trials. In addition to reducing viability and inducing apoptosis, resveratrol has also been reported to reduce ODC activity and induce SSAT activity in human colon cancer lines. The objectives of the current study were to extend the findings of earlier reports to uveal melanoma (C918) and breast cancer cells (MCF-7), examining whether or not resveratrol affects the activity of the enzymes in these cancer cell lines. Potential synergistic interactions between resveratrol and the inhibitors DFMO and DenSpm were also investigated. In our studies, resveratrol was found to reduce the expression of ODC and significantly induce the expression of SSAT as determined by real-time PCR. This is the first report of the effect of resveratrol on these enzymes in cells other than colon cancer cells. Resveratrol, DFMO and DenSpm each reduced cell viability and proliferation over a three-day course of treatment as determined by the conversion of resazurin to resorufin by viable cells (Cell Titer Blue Assay®). Combinations of resveratrol and DFMO or DenSpm affected proliferation to a greater degree than any of the compounds used alone. The ability of these compounds to induce apoptosis was tested by measuring the activity of the executioner caspases 3/7 in treated cells using the fluorogenic substrate Ac-DEVD-AMC. As was found in viability studies, the synergistic effects of the compounds were also observed with caspase activity, where the combinations of resveratrol and DFMO or DenSpm led to enhanced activation of the enzymes. 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 4214. doi:10.1158/1538-7445.AM2011-4214