Suppression of 7,12-dimethylbenz(a)anthracene-induced mammary carcinogenesis in rats by resveratrol: Role of nuclear factor-κB, cyclooxygenase 2, and matrix metalloprotease 9

We have reported recently that resveratrol (trans-3,4′,S-trihydroxystilbene), a polyphenolic phytoalexin found in grapes, fruits, and root extracts of the weed Polygonum cuspidatum, is a potent inhibitor of nuclear factor (NF)-κB activation. Because NF-κB suppression has been linked with chemoprevention, this prompted us to investigate the chemopreventive potential of resveratrol by testing it against mammary carcinogenesis induced by 7,12-dimethylbenz(a)anthracene (DMBA) in female Sprague Dawley rats. Dietary administration of resveratrol (10 ppm) had no effect on body weight gain and tumor volume but produced striking reductions in the incidence (45%; P < 0.05), multiplicity (55%; P < 0.001), and extended latency period of tumor development relative to DMBA-treated animals. Histopathological analysis of the tumors revealed that DMBA induced ductal carcinomas and focal microinvasion in situ (7 of 7), whereas treatment with resveratrol suppressed DMBA-induced ductal carcinoma. Immunohistochemistry and Western blot analysis revealed that resveratrol suppressed the DMBA-induced cyclooxygenase-2 and matrix metalloprotease-9 expression in the breast tumor. Gel shift analysis showed suppression of DMBA-induced NF-κB activation by resveratrol. Treatment of human breast cancer MCF-7 cells with resveratrol also suppressed the NF-κB activation and inhibited proliferation at S-G₂-M phase. Overall, our results suggest that resveratrol suppresses DMBA-induced mammary carcinogenesis, which correlates with down-regulation of NF-κB, cyclooxygenase-2, and matrix metalloprotease-9 expression.