title: RETRACTED: Combined Effect of Silica Nanoparticles and Benzo[a]pyrene on Cell Cycle Arrest Induction and Apoptosis in Human Umbilical Vein Endothelial Cells
abstract: Particulate matter (PM) such as ultrafine particulate matter (UFP) and the organic compound pollutants such as polycyclic aromatic hydrocarbon (PAH) are widespread in the environment. UFP and PAH are present in the air, and their presence may enhance their individual adverse effects on human health. However, the mechanism and effect of their combined interactions on human cells are not well understood. We investigated the combined toxicity of silica nanoparticles (SiNPs) (UFP) and Benzo[a]pyrene (B[a]P) (PAH) on human endothelial cells. Human umbilical vascular endothelial cells (HUVECs) were exposed to SiNPs or B[a]P, or a combination of SiNPs and B[a]P. The toxicity was investigated by assessing cellular oxidative stress, DNA damage, cell cycle arrest, and apoptosis. Our results show that SiNPs were able to induce reactive oxygen species generation (ROS). B[a]P, when acting alone, had no toxicity effect. However, a co-exposure of SiNPs and B[a]P synergistically induced DNA damage, oxidative stress, cell cycle arrest at the G2/M check point, and apoptosis. The co-exposure induced G2/M arrest through the upregulation of Chk1 and downregulation of Cdc25C, cyclin B1. The co-exposure also upregulated bax, caspase-3, and caspase-9, the proapoptic proteins, while down-regulating bcl-2, which is an antiapoptotic protein. These results show that interactions between SiNPs and B[a]P synergistically potentiated toxicological effects on HUVECs. This information should help further our understanding of the combined toxicity of PAH and UFP.
authors.affiliation: Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing 100069, China. asweto_collins@yahoo.com.|Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China. asweto_collins@yahoo.com.
authors.forename: Collins Otieno
authors.initials: CO
authors.lastname: Asweto
authors.affiliation: Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing 100069, China. wujing000032@126.com.|Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China. wujing000032@126.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing 100069, China. jingjinghe_2008@126.com.|Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China. jingjinghe_2008@126.com.
authors.forename: Hejing
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing 100069, China. fenglin615@163.com.|Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China. fenglin615@163.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Feng
authors.affiliation: Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing 100069, China. yangxiaozhe3@163.com.|Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China. yangxiaozhe3@163.com.
authors.forename: Xiaozhe
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing 100069, China. jcduan@ccmu.edu.cn.|Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China. jcduan@ccmu.edu.cn.
authors.forename: Junchao
authors.initials: J
authors.lastname: Duan
authors.affiliation: Department of Toxicology and Sanitary Chemistry, School of Public Health, Capital Medical University, Beijing 100069, China. zwsun@ccmu.edu.cn.|Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, China. zwsun@ccmu.edu.cn.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Sun
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001564:Benzo(a)pyrene / Q000633:toxicity*; D059447:Cell Cycle Checkpoints / Q000187:drug effects*; D004249:DNA Damage / Q000187:drug effects; D004784:Environmental Monitoring; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects*; D006801:Humans; D053758:Nanoparticles / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects; D052638:Particulate Matter / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D012822:Silicon Dioxide / Q000633:toxicity*
chemical_list: D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; D001564:Benzo(a)pyrene; D012822:Silicon Dioxide
keywords: Benzo[a]pyrene; HUVECs; co-exposure toxicity; silica nanoparticles