Zhu Wenbin, Cromie Meghan M, Cai Qingsong, Lv Tangfeng, Singh Kamaleshwar, Gao Weimin
Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, Texas, United States of America.
PLoS One. 2014 Mar 24;9(3):e92992. doi: 10.1371/journal.pone.0092992. eCollection 2014.
Benzo[a]pyrene (BaP), a well-known environmental carcinogen, promotes oxidative stress and DNA damage. Curcumin and vitamin E (VE) have potent antioxidative activity that protects cells from oxidative stress and cellular damage. The objectives of the present study were to investigate the adverse effects of BaP on normal human lung epithelial cells (BEAS-2B), the potential protective effects of curcumin and VE against BaP-induced cellular damage, and the molecular mechanisms of action. MTT assay, flow cytometry, fluorescence microplate assay, HPLC, qRT-PCR, and western blot were performed to analyze cytotoxicity, cell cycle, reactive oxygen species (ROS), BaP diol-epoxidation (BPDE)-DNA adducts, gene expression, and protein expression, respectively. Curcumin or VE prevented cells from BaP-induced cell cycle arrest and growth inhibition, significantly suppressed BaP-induced ROS levels, and decreased BPDE-DNA adducts. While CYP1A1 and 1B1 were induced by BaP, these inductions were not significantly reduced by curcumin or VE. Moreover, the level of activated p53 and PARP-1 were significantly induced by BaP, whereas this induction was markedly reduced after curcumin and VE co-treatment. Survivin was significantly down-regulated by BaP, and curcumin significantly restored survivin expression in BaP-exposed cells. The ratio of Bax/Bcl-2 was also significantly increased in cells exposed to BaP and this increase was reversed by VE co-treatment. Taken together, BaP-induced cytotoxicity occurs through DNA damage, cell cycle arrest, ROS production, modulation of metabolizing enzymes, and the expression/activation of p53, PARP-1, survivin, and Bax/Bcl-2. Curcumin and VE could reverse some of these BaP-mediated alterations and therefore be effective natural compounds against the adverse effects of BaP in lung cells.
苯并[a]芘（BaP）是一种著名的环境致癌物，可促进氧化应激和DNA损伤。姜黄素和维生素E（VE）具有强大的抗氧化活性，可保护细胞免受氧化应激和细胞损伤。本研究的目的是调查BaP对正常人肺上皮细胞（BEAS-2B）的不良影响、姜黄素和VE对BaP诱导的细胞损伤的潜在保护作用以及分子作用机制。分别进行MTT法、流式细胞术、荧光微孔板法、高效液相色谱法、qRT-PCR和蛋白质印迹法来分析细胞毒性、细胞周期、活性氧（ROS）、BaP二醇环氧化（BPDE）-DNA加合物、基因表达和蛋白质表达。姜黄素或VE可防止细胞因BaP诱导的细胞周期停滞和生长抑制，显著抑制BaP诱导的ROS水平，并减少BPDE-DNA加合物。虽然BaP诱导了CYP1A1和1B1，但姜黄素或VE并未显著降低这些诱导作用。此外，BaP显著诱导了活化的p53和PARP-1的水平，而在姜黄素和VE联合处理后，这种诱导作用明显降低。Survivin在BaP作用下显著下调，姜黄素可显著恢复BaP处理细胞中Survivin的表达。在暴露于BaP的细胞中，Bax/Bcl-2的比例也显著增加，而VE联合处理可逆转这种增加。综上所述，BaP诱导的细胞毒性是通过DNA损伤、细胞周期停滞、ROS产生、代谢酶的调节以及p53、PARP-1、Survivin和Bax/Bcl-2的表达/激活而发生的。姜黄素和VE可以逆转BaP介导的一些改变，因此是对抗BaP对肺细胞不良影响的有效天然化合物。
