Molecular and Cellular Pharmacology 3,3′,4,5,5′-pentahydroxy-trans-stilbene, a resveratrol derivative, induces apoptosis in colorectal carcinoma cells via oxidative stress Haitao Li a , William Ka Kei Wu b,c,d , Zongping Zheng a , Chun Tao Che e , Zhi Jie Li b , Dan Dan Xu e , Clover Ching Man Wong b , Cai Guo Ye b , Joseph Jao Yiu Sung c,d , Chi Hin Cho b,d, ⁎, Mingfu Wang a, ⁎ a School of Biological Sciences, The University of Hong Kong, Hong Kong, China b School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China c Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong, China d Institute of Digestive Diseases, The Chinese University of Hong Kong, Hong Kong, China e School of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong, China abstract article info Article history: Received 13 November 2009 Received in revised form 15 March 2010 Accepted 4 April 2010 Available online 23 April 2010 Keywords: Hydroxylated resveratrol derivative Colon cancer Apoptosis Oxidative stress Resveratrol exhibits anti-tumor properties against different types of cancer. In this study, several polyhydroxylated resveratrol derivatives were prepared with the aim of discovering new leading compounds with clinical potential for human colon cancer chemotherapy. Among these compounds, 3,3′,4,5,5′-pentahydroxy-trans-stilbene (PHS) displayed the most potent cytotoxicity and triggered apoptosis in HT-29 cells as evidenced by increased poly(ADP-ribose) polymerase (PARP) cleavage, elevated levels of cytoplasmic nucleosomes and DNA fragmentation. Further mechanistic analysis revealed that PHS- induced apoptosis was caspase-dependent and mediated by its pro-oxidative action through up-regulation of reactive oxidative species generation and depletion of intracellular glutathione. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Interest in the pharmacological effects of phytochemicals on cancer treatment and prevention has increased dramatically over the past twenty years (Scott et al., 2009). During the course of compound identification, resveratrol (3,4′,5-trihydroxy-trans-stilbene) and its derivatives have emerged to hold promise for their potent in vitro and in vivo anticancer activities (Jang et al., 1997; Pervaiz, 2004; Baur and Sinclair, 2006). Chemically, resveratrol and its derivatives belong to a class of chemicals known as stilbenes which exhibit variable antioxidative, anti-inflammatory and cytotoxic activity. Among resveratrol analogs studied so far, growing experimental evidence suggests that polyhydroxylated stilbenes may be a novel class of disease chemopreventive and therapeutic agents. For instances, several hydroxylated stilbenes exert much more potent radical scavenging activity than resveratrol (Wang et al., 1999; Murias et al., 2005); potently inhibits cyclooxygenase-2 (COX-2) with a selectivity index comparable to celecoxib, a selective COX-2 inhibitor already well-established in the market (Murias et al., 2004; Zykova et al., 2008); effectively block cell transformation induced by epidermal growth factor or 12-O-tetradecanoylphorbol-13-acetate (She et al., 2003; Lee et al., 2008). Moreover, several polyhydroxylated stilbenes display much higher cytotoxic activity than resveratrol in cancer cell lines (Lu et al., 2001; Lion et al., 2005; Murias et al., 2005; Horvath et al., 2006; Murias et al., 2008). Taken together, hydroxylated stilbenes seem to be a sub-group of great interest and undoubtedly worthy of a further investigation. Nevertheless, studies on the bioactivities and molecular mechanisms of hydroxylated stilbenes have been hindered by their limited availabilities from natural sources. In this study, several polyhydroxylated stilbenes were prepared with the aim of discovering new leading compounds with clinical potential for human colon cancer chemotherapy. Based on their cytotoxic effect on the human colon cancer cell line HT-29, 3,3′,4,5,5′- pentahydroxy-trans-stilbene (PHS) was found to be the most active one among compounds tested, and its possible mechanism of action was further elucidated using molecular pharmacological approach. 2. Materials and methods 2.1. Reagents and chemicals Resveratrol was purchased from Sigma-Aldrich (St Louis, MO, USA). Oxyresveratrol was isolated from the dried twigs of Morus alba L. (Li et al., 2007), while four other polyhydroxylated resveratrol European Journal of Pharmacology 637 (2010) 55–61 ⁎ Corresponding authors. Wang is to be contacted at School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China. Tel.: + 852 2299 0338; fax: + 852 2299 0340. Cho, School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China. Tel.: + 852 2609 6886; fax: + 852 2607 5139. E-mail addresses: chcho@cuhk.edu.hk (C.H. Cho), mfwang@hkusua.hku.hk (M. Wang). 0014-2999/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.ejphar.2010.04.009 Contents lists available at ScienceDirect European Journal of Pharmacology journal homepage: www.elsevier.com/locate/ejphar