Lee Ki Won, Kang Nam Joo, Rogozin Evgeny A, Oh Sang-Muk, Heo Yong Seok, Pugliese Angelo, Bode Ann M, Lee Hyong Joo, Dong Zigang
Hormel Institute, University of Minnesota, Austin, MN 55912, USA.
Int J Cancer. 2008 Dec 1;123(11):2487-96. doi: 10.1002/ijc.23830.
Resveratrol, present in grapes and red wine, is reported to be a natural chemopreventive agent against cancer. However, the concentrations required to exert these effects may be difficult to achieve by drinking only 1 or 2 glasses of red wine a day. Therefore, developing more potent, nontoxic analogues of resveratrol may provide a feasible means of achieving an effective physiologic concentration. Here we report that the resveratrol analogue, 3,5,3',4',5'-pentahydroxy-trans-stilbene (RSVL2), inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neoplastic transformation in JB6 P+ mouse epidermal cells. Further, we identified MEK/ERK signaling as the direct molecular target for the anticancer effects of RSVL2 and demonstrated that RSVL2 inhibited MEK1, but not Raf1 or ERK2 kinase activity. RSVL2 also dose-dependently suppressed MEK1 kinase activity induced by TPA and the inhibition of H-Ras-induced cell transformation was much stronger for RSVL2 than for PD098059 or resveratrol. Both in vitro and ex vivo pull-down assays indicated that RSVL2, but not resveratrol, directly bound with GST-MEK1, but did not compete with ATP for binding. Docking data indicated that the low inhibitory activity of resveratrol might be due to the lack of the hydroxyl group at the meta position of the B ring, thereby preventing resveratrol from forming a hydrogen bond with the backbone amide group of Ser212, which is the key interaction for stabilizing the inactive conformation of the activation loop.
据报道，存在于葡萄和红酒中的白藜芦醇是一种天然的抗癌化学预防剂。然而，仅通过每天饮用1或2杯红酒来达到发挥这些作用所需的浓度可能很困难。因此，开发更有效、无毒的白藜芦醇类似物可能提供一种实现有效生理浓度的可行方法。在此我们报告，白藜芦醇类似物3,5,3',4',5'-五羟基反式芪（RSVL2）可抑制12-O-十四烷酰佛波醇-13-乙酸酯（TPA）诱导的JB6 P+小鼠表皮细胞的肿瘤转化。此外，我们确定MEK/ERK信号传导是RSVL2抗癌作用的直接分子靶点，并证明RSVL2抑制MEK1，但不抑制Raf1或ERK2激酶活性。RSVL2还剂量依赖性地抑制TPA诱导的MEK1激酶活性，并且RSVL2对H-Ras诱导的细胞转化的抑制作用比对PD098059或白藜芦醇更强。体外和离体下拉试验均表明，RSVL2而非白藜芦醇直接与GST-MEK1结合，但不与ATP竞争结合。对接数据表明，白藜芦醇的低抑制活性可能是由于B环间位缺乏羟基，从而阻止白藜芦醇与Ser212的主链酰胺基团形成氢键，而Ser212是稳定激活环非活性构象的关键相互作用。
