Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany.
Mol Pharm. 2011 Jun 6;8(3):976-81. doi: 10.1021/mp1004492. Epub 2011 Apr 7.
Genotoxicity information on polymers used for gene delivery is scant, but of great concern, especially when developing polymeric nanocarriers as nonviral vector systems for cancer treatment. The genotoxicity of some engineered nanomaterials, e.g., metal oxides like ZnO, TiO₂, and CuO but also carbon based materials like carbon black or nanotubes, has commonly been related to oxidative stress, and subsequent inflammation. Recent studies of poly(ethylene imine) (PEI)-based polymers, important nonviral vector systems for pDNA and siRNA, might raise concerns because of their toxic effects dominated by cellular oxidative stress and inflammatory responses, similar to the mentioned effects of engineered nanoparticles. In this study, we employed a FE1-MutaMouse lung epithelial cell line based mutation assay to determine the genotoxicity of three PEI-based polymers and nanosized zinc oxide particles (NZO), all of which have previously been shown to trigger oxidative stress and inflammation. In addition, oxidative DNA damage (8-OH-dG) in FE1 cells was assessed by ELISA. The well-known carcinogen benzo[a]pyrene (B[a]P) was used as positive control. FE1 lung epithelial cells were exposed for eight sequential 72 h incubations, and reporter-gene mutation frequency or 8-OH-dG formation was determined to assess mutagenicity and oxidative DNA damage, respectively. No cytotoxic effects were detected at the exposure levels examined, which are representative of PEI concentrations normally used in in vitro transfection studies. In contrast to B[a]P, neither PEI-polymers nor NZO showed any significant mutagenic activity or oxidative DNA damage in the exposed cells, although PEI-based polymers have been shown to generate significant levels of cellular stress and inflammatory responses. We suggest that the lack of any detectable mutagenic/genotoxic activity of the PEI-based polymers studied here is a crucial step toward a safe use of such nanocarriers in clinical trials.
用于基因传递的聚合物的遗传毒性信息很少，但非常令人关注，尤其是在将聚合物纳米载体开发为癌症治疗的非病毒载体系统时。一些工程纳米材料的遗传毒性，例如 ZnO、TiO2 和 CuO 等金属氧化物，以及碳黑或纳米管等碳基材料，通常与氧化应激和随后的炎症有关。最近对聚（乙二亚胺）（PEI）基聚合物的研究，作为 pDNA 和 siRNA 的重要非病毒载体系统，可能会引起关注，因为它们的毒性作用主要由细胞氧化应激和炎症反应引起，类似于上述工程纳米颗粒的作用。在这项研究中，我们使用基于 FE1-MutaMouse 肺上皮细胞系的突变测定来确定三种 PEI 基聚合物和纳米氧化锌颗粒（NZO）的遗传毒性，所有这些都已被证明会引发氧化应激和炎症。此外，还通过 ELISA 评估 FE1 细胞中的氧化 DNA 损伤（8-OH-dG）。将已知的致癌物质苯并[a]芘（B[a]P）用作阳性对照。FE1 肺上皮细胞接受了连续 8 个 72 小时的孵育，通过测定报告基因突变频率或 8-OH-dG 形成来分别评估诱变活性和氧化 DNA 损伤。在所检查的暴露水平下未检测到细胞毒性作用，这些暴露水平代表了通常在体外转染研究中使用的 PEI 浓度。与 B[a]P 相反，PEI 聚合物和 NZO 都没有在暴露的细胞中显示出任何明显的致突变活性或氧化 DNA 损伤，尽管已经证明 PEI 基聚合物会产生显著水平的细胞应激和炎症反应。我们认为，缺乏可检测的致突变/遗传毒性活性是将这些纳米载体安全用于临床试验的关键步骤。
