Che Bizhong, Luo Qiulin, Zhai Bingzhong, Fan Guoqiang, Liu Zhiyong, Cheng Kaiming, Xin Lili
School of Public Health, Medical College of Soochow University, 199 Renai Road, Suzhou, Jiangsu, 215123, China.
Suzhou Industrial Park Centers for Disease Control and Prevention, 58 Suqian Road, Suzhou, Jiangsu, China.
Environ Toxicol. 2017 Sep;32(9):2203-2211. doi: 10.1002/tox.22433. Epub 2017 Jun 1.
The intense commercial application of silver nanoparticles (AgNPs) has been raising concerns about their potential adverse health effects to human. This study aimed to explore the potency of AgNPs to induce GADD45α gene, an important stress sensor, and its relationships with the cytotoxicity and genotoxicity elicited by AgNPs.
Two established HepG2 and A549 cell lines containing the GADD45α promoter-driven luciferase reporter were treated with increasing concentrations of AgNPs for 48 hours. After the treatment, transcriptional activation of GADD45α indicated by luciferase activity, cell viability, cell cycle arrest, and levels of genotoxicity were determined. The uptake and intracellular localization of AgNPs, cellular Ag doses as well as Ag release were also detected.
AgNPs could activate GADD45α gene at the transcriptional level as demonstrated by the dose-dependent increases in luciferase activity in both the reporter cells. The relative luciferase activity was greater than 12× the control level in HepG2-luciferase cells at the highest concentration tested where the cell viability decreased to 17.0% of the control. These results was generally in accordance with the positive responses in cytotoxicity, cell cycle arrest of Sub G1 and G2/M phase, Olive tail moment, micronuclei frequency, and the cellular Ag content.
The cytotoxicity and genotoxicity of AgNPs seems to occur mainly via particles uptake and the subsequent liberation of ions inside the cells. And furthermore, the GADD45α promoter-driven luciferase reporter cells, especially the HepG2-luciferase cells, could provide a new and valuable tool for predicting nanomaterials genotoxicity in humans.
银纳米颗粒（AgNPs）的广泛商业应用引发了人们对其可能对人类健康产生不良影响的担忧。本研究旨在探讨AgNPs诱导重要应激传感器GADD45α基因的能力，以及其与AgNPs引起的细胞毒性和遗传毒性之间的关系。
用浓度递增的AgNPs处理两种已建立的含有GADD45α启动子驱动荧光素酶报告基因的HepG2和A549细胞系48小时。处理后，测定荧光素酶活性所指示的GADD45α转录激活、细胞活力、细胞周期阻滞和遗传毒性水平。还检测了AgNPs的摄取和细胞内定位、细胞内银剂量以及银释放情况。
AgNPs可在转录水平激活GADD45α基因，两种报告细胞中荧光素酶活性均呈剂量依赖性增加。在测试的最高浓度下，HepG2-荧光素酶细胞中的相对荧光素酶活性比对照水平高12倍以上，此时细胞活力降至对照的17.0%。这些结果总体上与细胞毒性、亚G1和G2/M期细胞周期阻滞、橄榄尾矩、微核频率以及细胞内银含量的阳性反应一致。
AgNPs的细胞毒性和遗传毒性似乎主要通过颗粒摄取以及随后细胞内离子的释放而发生。此外，GADD45α启动子驱动的荧光素酶报告细胞，尤其是HepG2-荧光素酶细胞，可为预测纳米材料对人类的遗传毒性提供一种新的有价值的工具。
