Abstract 4876: Effects of a combination of resveratrol and sulforaphane on mutagenesis and DNA adduct formation in rat mammary tissue and a rat mammary fibroblast cell line.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC In this study we investigated the effects of the combination sulforaphane (Sul) and resveratrol (Rev) on carcinogen metabolism to DNA adducts in rat mammary fibroblasts, and on DMBA-induced mutagenesis in mammary tissue from rats treated in vivo. The use of combinations of potential cancer chemopreventive agents has become one strategy to optimize chemoprevention. By targeting more than one pathway/process it may be possible to impact prevention by additive or synergistic effects, and utilize lower doses of agents that might have toxic effects at higher doses. We have previously tested a number of potential inhibitors of mutagenesis induced by the rat mammary carcinogen, 7,12-dimethylbenzanthrace (DMBA) in rat mammary epithelial and fibroblast cell lines (isolated by Dr. P.D. Josephy from lacI rats, Mutat Res, 497: 39-47, 2001). We had compared binary combinations of the agents, sulforaphane (Sul), resveratrol (Res), lipoic acid, epigallocatechin gallate, a vitamin C and E mix, and N-acetylcysteine. The agents alone had minor effects, but the combination of Sul and Res inhibited mutagenesis by about 40%. The current study extended this finding. In the metabolism study, HPLC of metabolites was employed; benzo(a)pyrene (BaP), rather than DMBA was used as the carcinogen, as standards of BaP metabolites, but not those of DMBA were available. BaP like DMBA is a carcinogenic polycyclic aromatic hydrocarbon. Fibroblasts were used, as these metabolized BaP much more effectively than epithelial cells. In the presence of 4uM BaP, in the absence of inhibitors, the cells generated 498 ± 83 pg/ml medium of the BaP-7,8 dihydrodiol -9,10 epoxide decomposition product, BaP 7,8,9,10 tetrol. This was reduced by 0.18uM Sul to 153 ± 48, by 4uM Res to 416 ± 87 and by a combination of the agents to 83 ± 37 pg/ml. The reduction was significant for Sul and for the combination. For the in vivo study rats were treated (6/group) by gavage with a single dose of 80 mg/kg DMBA. Two weeks before the DMBA treatment and continuing for 4 wks, rats received 50 mg/L Res, 120 mg/L Sul, and combinations of the agents at 50 and 120 mg/L or ½ the doses in drinking water. Eight wks after the DMBA treatment the rats were euthanized and mutagenesis in the cII gene was measured. The treatments and mutant fractions resp. were: DMBA alone, 9.1 ± 5.0; DMBA + Res, 8.9 ± 3.4; Sul, 8.2 ± 2.0; Res + Sul, 7.1 ± 2.8; Res + Sul, ½ dose, 7.9 ± 3.4; control, 1.3 ± 1.0. DMBA-induced mutagenesis was inhibited by both combination treatments, and Sul alone, although the inhibitions did not reach statistical significance, possibly because of large inter-animal variations. Taken together the results support the use of combinations of agents to enhance chemoprotection. Supported by the Susan Komen Foundation grant # KG080836. Citation Format: Peter G. Sacks, Wieslawa Kosinska, Mitaliben Contractor, Tian-Zhen Han, Joseph B. Guttenplan. Effects of a combination of resveratrol and sulforaphane on mutagenesis and DNA adduct formation in rat mammary tissue and a rat mammary fibroblast cell line. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4876. doi:10.1158/1538-7445.AM2013-4876