Inhibition of cell transformation by resveratrol and its derivatives: differential effects and mechanisms involved Qing-Bai She 1 , Wei-Ya Ma 1 , Mingfu Wang 2 , Akira Kaji 1 , Chi-Tang Ho 2 and Zigang Dong* ,1 1 The Hormel Institute, University of Minnesota 3 , 801 16th Avenue NE, Austin, MI 55912, USA; 2 Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA Resveratrol, a constituent of grapes and other foods, has been reported to be a potential cancer chemopreventive agent. Our previous study showed that the antitumor activity of resveratrol occurs through mitogen-activated protein kinases-mediated p53 activation and induction of apoptosis. To develop more effective agents with fewer side effects for the chemoprevention of cancer, we investigated the effect of resveratrol and its structurally related derivatives on epidermal growth factor (EGF)- induced cell transformation. Our results provided the first evidence that one of the resveratrol derivatives exerted a more potent inhibitory effect than resveratrol on EGF- induced cell transformation, but had less cytotoxic effects on normal nontransformed cells. Compared to resveratrol, this compound also caused cell cycle arrest in the G1 phase, but did not induce p53 activation and apoptosis. Furthermore, this compound, but not resveratrol, mark- edly inhibited EGF-induced phosphatidylinositol-3 kinase (PI-3K) and Akt activation. Collectively, these data suggested that the higher antitumor effect of the compound compared to resveratrol, may act through a different mechanism by mainly targeting PI-3K/Akt signaling pathways. Oncogene (2003) 22, 2143–2150. doi:10.1038/sj.onc.1206370 Keywords: resveratrol; resveratrol derivatives; cell transformation; p53; PI-3K/Akt; chemoprevention Introduction Chemoprevention, which is recognized as the pharma- cological intervention with synthetic or naturally occur- ring agents to prevent, inhibit or reverse carcinogenesis or prevent the development of invasive cancer, has become increasingly appreciated as a new strategy in the fight against cancer (Hong and Sporn, 1997; Kelloff et al., 2000; Sporn and Suh, 2000). In recent years, many naturally occurring compounds, commonly present in the diet and in beverages consumed by the human population, have gained considerable attention as chemopreventive agents (Hong and Sporn, 1997; Kelloff et al., 2000; Sporn and Suh, 2000). In this regard, resveratrol (3,5,4 0 -trihydroxy-trans-stilbene) (Figure 1), a phytoalexin found in a multitude of dietary plants including grapes and peanuts, has been shown to provide cancer chemopreventive effects in different systems based on its striking inhibition of diverse cellular events associated with tumor initiation, promo- tion and progression (Jang et al., 1997). This is partly attributable to its antioxidant activities and its inhibition of cyclooxygenase 1 and 2 (Jang et al., 1997; Subbar- amaiah et al., 1998). An accumulation of evidence has further shown that the anticancer properties of resver- atrol are related to its ability to downregulate activation of NFkB (Tsai et al., 1999), cause cell cycle arrest in the G1 phase (Hsieh and Wu, 1999; Adhami et al., 2001; Ahmad et al., 2001) or in the S–G2 phase transition (Ragione et al., 1998), or to trigger apoptosis in a variety of cancer cell lines (Clement et al., 1998; Hsieh and Wu, 1999; Surh et al., 1999; Park et al., 2001). Recently, we offered a possible molecular mechanism by which the antitumor activity of resveratrol was shown to occur through mitogen-activated protein kinases-mediated p53 activation and subsequent induction of apoptosis (Huang et al., 1999b; She et al., 2001, 2002). To better understand the mechanistic basis for the chemopreven- tive properties of resveratrol and develop more effective agents for the prevention of cancer, we synthesized two resveratrol derivatives designated as 3,5,3 0 ,4 0 -tetrahy- droxy-trans-stilbene (RSVL-1) and 3,5,3 0 ,4 0 ,5 0 -pentahy- droxy-trans-stilbene (RSVL-2) (Figure 1). We used a mouse JB6 epidermal cell line, a well-developed cell culture model for studying tumor promotion (Bernstein and Colburn, 1989; Dong et al., 1994; Huang et al., 1996, 1999a, b), to investigate the relation of structure and antitumor activity of resveratrol and its derivatives. Furthermore, we studied the molecular mechanisms involved in their chemopreventive effect on cancer. Results and discussion RSVL-2 exhibits a potent inhibitory effect on epidermal growth factor (EGF)-induced cell transformation Previous studies examining the chemopreventive effects of resveratrol focused mainly on 12-O-tetradecanoyl- Received 9 April 2002; revised 3 December 2002; accepted 6 January 2003 *Correspondence: Z Dong; E-mail: zgdong@hi.umn.edu. 3 The University of Minnesota is an equal opportunity educator and employer Oncogene (2003) 22, 2143–2150 & 2003 Nature Publishing Group All rights reserved 0950-9232/03 $25.00 www.nature.com/onc