She Q B, Bode A M, Ma W Y, Chen N Y, Dong Z
The Hormel Institute, University of Minnesota, Austin 55912, USA.
Cancer Res. 2001 Feb 15;61(4):1604-10.
Resveratrol, a phytoalexin found in grapes, berries, and peanuts, is one of the most promising agents for cancer prevention. Our previous study showed that the antitumor activity of resveratrol occurs through p53-mediated apoptosis. In this study, we have elucidated the potential signaling components underlying resveratrol-induced p53 activation and induction of apoptosis. We found that in a mouse JB6 epidermal cell line, resveratrol activated extracellular-signal-regulated protein kinases (ERKs), c-Jun NH2-terminal kinases (JNKs), and p38 kinase and induced serine 15 phosphorylation of p53. Stable expression of a dominant negative mutant of ERK2 or p38 kinase or their respective inhibitor, PD98059 or SB202190, repressed the phosphorylation of p53 at serine 15. In contrast, overexpression of a dominant negative mutant of JNKI had no effect on the phosphorylation. Most importantly, ERKs and p38 kinase formed a complex with p53 after treatment with resveratrol. Strikingly, resveratrol-activated ERKs and p38 kinase, but not JNKs, phosphorylated p53 at serine 15 in vitro. Furthermore, pretreatment of the cells with PD98059 or SB202190 or stable expression of a dominant negative mutant of ERK2 or p38 kinase impaired resveratrol-induced p53-dependent transcriptional activity and apoptosis, whereas constitutively active MEK1 increased the transcriptional activity of p53. These data strongly suggest that both ERKs and p38 kinase mediate resveratrol-induced activation of p53 and apoptosis through phosphorylation of p53 at serine 15.
白藜芦醇是一种存在于葡萄、浆果和花生中的植保素,是最有前景的癌症预防剂之一。我们之前的研究表明,白藜芦醇的抗肿瘤活性是通过p53介导的细胞凋亡实现的。在本研究中,我们阐明了白藜芦醇诱导p53激活和细胞凋亡诱导的潜在信号成分。我们发现,在小鼠JB6表皮细胞系中,白藜芦醇激活了细胞外信号调节蛋白激酶(ERK)、c-Jun氨基末端激酶(JNK)和p38激酶,并诱导了p53丝氨酸15位的磷酸化。ERK2或p38激酶的显性负突变体或其各自的抑制剂PD98059或SB202190的稳定表达抑制了p53丝氨酸15位的磷酸化。相比之下,JNKI显性负突变体的过表达对磷酸化没有影响。最重要的是,用白藜芦醇处理后,ERK和p38激酶与p53形成了复合物。令人惊讶的是,白藜芦醇激活的ERK和p38激酶,而不是JNK,在体外使p53丝氨酸15位磷酸化。此外,用PD98059或SB202190预处理细胞或ERK2或p38激酶显性负突变体的稳定表达损害了白藜芦醇诱导的p53依赖性转录活性和细胞凋亡,而组成型活性MEK1增加了p53的转录活性。这些数据强烈表明,ERK和p38激酶都通过使p53丝氨酸15位磷酸化来介导白藜芦醇诱导的p53激活和细胞凋亡。