Buhrmann Constanze, Shayan Parviz, Popper Bastian, Goel Ajay, Shakibaei Mehdi
Institute of Anatomy, Ludwig-Maximilian-University Munich, Pettenkoferstrasse 11, Munich D-80336, Germany.
Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran 141556453, Iran.
Nutrients. 2016 Mar 5;8(3):145. doi: 10.3390/nu8030145.
Sirt1 is a NAD⁺-dependent protein-modifying enzyme involved in regulating gene expression, DNA damage repair, metabolism and survival, as well as acts as an important subcellular target of resveratrol. The complex mechanisms underlying Sirt1 signaling during carcinogenesis remain controversial, as it can serve both as a tumor promoter and suppressor. Whether resveratrol-mediated chemopreventive effects are mediated via Sirt1 in CRC growth and metastasis remains unclear; which was the subject of this study. We found that resveratrol suppressed proliferation and invasion of two different human CRC cells in a dose-dependent manner, and interestingly, this was accompanied with a significant decrease in Ki-67 expression. By transient transfection of CRC cells with Sirt1-ASO, we demonstrated that the anti-tumor effects of resveratrol on cells was abolished, suggesting the essential role of this enzyme in the resveratrol signaling pathway. Moreover, resveratrol downregulated nuclear localization of NF-κB, NF-κB phosphorylation and its acetylation, causing attenuation of NF-κB-regulated gene products (MMP-9, CXCR4) involved in tumor-invasion and metastasis. Finally, Sirt1 was found to interact directly with NF-κB, and resveratrol did not suppress Sirt1-ASO-induced NF-κB phosphorylation, acetylation and NF-κB-regulated gene products. Overall, our results demonstrate that resveratrol can suppress tumorigenesis, at least in part by targeting Sirt1 and suppression of NF-κB activation.
沉默调节蛋白1(Sirt1)是一种依赖烟酰胺腺嘌呤二核苷酸(NAD⁺)的蛋白质修饰酶,参与调节基因表达、DNA损伤修复、代谢和细胞存活,也是白藜芦醇的一个重要亚细胞靶点。在致癌过程中,Sirt1信号传导的复杂机制仍存在争议,因为它既可以作为肿瘤促进剂,也可以作为肿瘤抑制剂。白藜芦醇介导的化学预防作用是否通过Sirt1在结直肠癌的生长和转移中发挥作用仍不清楚;这是本研究的主题。我们发现白藜芦醇以剂量依赖性方式抑制两种不同的人结直肠癌细胞的增殖和侵袭,有趣的是,这伴随着Ki-67表达的显著降低。通过用Sirt1反义寡核苷酸(Sirt1-ASO)瞬时转染结直肠癌细胞,我们证明白藜芦醇对细胞的抗肿瘤作用被消除,表明该酶在白藜芦醇信号通路中起重要作用。此外,白藜芦醇下调核因子κB(NF-κB)的核定位、NF-κB磷酸化及其乙酰化,导致参与肿瘤侵袭和转移的NF-κB调节基因产物(基质金属蛋白酶-9、趋化因子受体4)减少。最后,发现Sirt1直接与NF-κB相互作用,白藜芦醇不抑制Sirt1-ASO诱导的NF-κB磷酸化、乙酰化及NF-κB调节基因产物。总体而言,我们的结果表明,白藜芦醇可以抑制肿瘤发生,至少部分是通过靶向Sirt1和抑制NF-κB激活来实现的。