PO.CH01.05 · 化学
橄榄苦苷和石榴酸对MCF-7细胞毒性的差异机制及氧化应激与过氧化物还原酶抗氧化剂的作用
Differential mechanisms of MCF-7 cytotoxicity by oleuropein and punicic acid and the role of oxidative stress and peroxiredoxin antioxidants
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
许多天然化合物已被证明在体外和/或体内对乳腺癌细胞具有抗癌特性，人们越来越有兴趣了解这些产品作为传统化疗替代方案的作用及作用机制。橄榄苦苷是一种源自橄榄叶的多酚类化合物，已在乳腺癌及其他癌症中显示出抗氧化和抗癌特性。石榴酸是一种存在于石榴籽中的多不饱和脂肪酸，也在多种癌症中显示出抗氧化和抗癌作用。MCF-7细胞系是雌激素受体阳性（ER+）乳腺癌的重要模型，有助于研究这些天然产物的作用及机制。我们试图在该模型中比较橄榄苦苷和石榴酸，并假设两者均会通过增加氧化应激和破坏线粒体功能诱导MCF-7细胞毒性。细胞用50或200 ug/ml橄榄苦苷、10或50 ug/ml石榴酸或70%乙醇（作为对照）处理72小时。采用乳酸脱氢酶（LDH）释放测定法测量细胞毒性，采用MitoSOX测定法评估线粒体ROS及丙二醛（MDA）定量评估脂质过氧化以评估氧化应激。我们发现橄榄苦苷诱导LDH释放显著增加，并出现与凋亡一致的形态学改变，但ROS无显著增加。石榴酸诱导LDH释放呈剂量依赖性增加，并额外导致线粒体ROS和脂质过氧化增加。由于我们此前报道橄榄苦苷和石榴酸均在这些细胞中显著诱导过氧化物还原酶抗氧化基因的表达，我们还着手研究抑制Prdx对这些化合物易感性的影响。使用针对六个Prdx基因中每一个的瞬时siRNA转染，我们发现抑制Prdx2、Prdx3、Prdx4和Prdx5显著增加MCF-7对石榴酸的易感性，但对橄榄苦苷则不然。总之，我们的数据表明这些化合物通过不同的机制诱导细胞毒性，其中氧化应激在石榴酸诱导的毒性中起主要作用。靶向过氧化物还原酶可能是未来治疗应用中提高乳腺癌细胞对这些化合物易感性的有效策略。
查看英文原文 English abstract
Many natural compounds have been shown to possess anticancer properties against breast cancer cells in vitro and/or in vivo, and there is increased interest in understanding the effects and mechanisms of action of such products as an alternative to traditional chemotherapy. Oleuropein is a polyphenolic compound derived from olive leaves that has demonstrated antioxidant and anticancer properties in breast cancer and other cancers. Punicic acid is a poly-5-unsaturated fatty acid found in pomegranate seeds that has also shown antioxidant and anticancer effects in various cancers. The MCF-7 cell line is an important model for estrogen receptor-positive (ER+) breast cancer which is useful for studying the effects and mechanisms of these natural products. We sought to compare oleuropein and punicic acid in this model and hypothesized that both would induce cytotoxicity in MCF-7 cells by increasing the oxidative stress and disrupting mitochondrial function. Cells were treated with 50 or 200 ug/ml oleuropein, 10 or 50 ug/ml punicic acid, or 70% ethanol as a control for 72 hours. Cytotoxicity was measured using an lactate dehydrogenase (LDH) release assay, and oxidative stress was assessed using the MitoSOX assay for mitochondrial ROS and malondialdehyde (MDA) quantification for lipid peroxidation. We found that oleuropein induced a significant increase in LDH release, and morphological changes consistent with apoptosis, but no significant increase in ROS. Punicic acid induced a dose-dependent increase in LDH release, and additionally led to an increase in mitochondrial ROS and lipid peroxidation. Since we previously reported significant induction of expression of the Peroxiredoxin antioxidant genes by both oleuropein and punicic acid in these cells, we also set out to examine the effects of Prdx suppression on susceptibility to these compounds. Using transient siRNA transfections targeting each of the six Prdx genes, we found that suppression of Prdx2, Prdx3, Prdx4 and Prdx5 significantly increased MCF-7 susceptibility to punicic acid, but not to oleuropein. Together, our data suggest that these compounds induce cytotoxicity through different mechanisms, with oxidative stress playing a major role in punicic acid-induced toxicity. Targeting peroxiredoxins may be an effective strategy for increasing breast cancer cell susceptibility to these compounds in future therapeutic applications.
利益披露 Disclosure
S. Diiorio, None..
B. Quitmeyer, None..
S. A. Phelan, None.