Graphene Oxide–Silver Nanoparticle Nanocomposites Induce Oxidative Stress and Aberrant Methylation in Caprine Fetal Fibroblast Cells

Abstract

Graphene oxide–silver nanoparticle (GO-AgNPs) nanocomposites have drawn much attention for their potential in biomedical uses. However, the potential toxicity of GO-AgNPs in animals and humans remains unknown, particularly in the developing fetus. Here, we reported the GO-AgNP-mediated cytotoxicity and epigenetic alteration status in caprine fetal fibroblast cells (CFFCs). In brief, the proliferation and apoptosis rate of GO-AgNP-treated CFFCs (4 and 8 µg/mL of GO-AgNPs) were measured using the cell-counting kit (CCK-8) assay and the annexin V/propidium iodide (PI) assay, respectively. In addition, the oxidative stress induced by GO-AgNPs and detailed mechanisms were studied by evaluating the generation of reactive oxygen species (ROS), superoxide dismutase (SOD), lactate dehydrogenase (LDH), malondialdehyde (MDA), and caspase-3 and abnormal methylation. The expression of pro- and anti-apoptotic genes and DNA methyltransferases was measured using reverse transcription followed by RT-qPCR. Our data indicated that GO-AgNPs cause cytotoxicity in a dose-dependent manner. GO-AgNPs induced significant cytotoxicity by the loss of cell viability, production of ROS, increasing leakage of LDH and level of MDA, increasing expression of pro-apoptotic genes, and decreasing expression of anti-apoptotic genes. GO-AgNPs incited DNA hypomethylation and the decreased expression of DNMT3A. Taken together, this study showed that GO-AgNPs increase the generation of ROS and cause apoptosis and DNA hypomethylation in CFFCs. Therefore, the potential applications of GO-AgNPs in biomedicine should be re-evaluated.

The Preliminary Study on the Proapoptotic Effect of Reduced Graphene Oxide in Breast Cancer Cell Lines

“…Apoptosis and necrosis are two of the main types of cell death, which have been discussed in previous reports [6,9,10]. The two main mechanisms for inducing apoptosis include the mitochondrial (intrinsic) pathway and receptor-mediated (extrinsic) pathway.…”

“…To date, there are no clear mechanisms by which rGO induces cytotoxicity. Various physiochemical properties of rGO, including size, shape, structure, hydrophobicity, surface functionalization, dose administration, purity and elemental composition, allow rGO to exhibit many mechanisms of action in cancer cells [9][10][11]. Key mechanisms that appear to be related to GFNs include the production of reactive oxygen species (ROS).…”

Molecular Biocompatibility of a Silver Nanoparticle Complex with Graphene Oxide to Human Skin in a 3D Epidermis In Vitro Model

“…These studies were performed on in vitro models of fibroblasts and HUVECs and in ovo—chicken embryo chorioallantoic membrane. Other model studies on the toxicity of the AgNP-GO complex carried out on zebrafish embryos and caprine fetal fibroblasts documented the dose-dependent nature of the toxicity of this material [ 24 , 25 ]. Interesting studies on the toxicity of the AgNP-GO in vitro were carried out on macrophages.…”

Direct and Indirect Genotoxicity of Graphene Family Nanomaterials on DNA—A Review

“…Ting et al [91] firstly proved that GQDs can inhibit the DNA methylation of transcription factor Sox2 and regulated DNA methyltransferase and demethyltransferase expressions. Global DNA hypomethylation of caprine fetal fibroblast cells, which are exposed to GO-AgNPs, might result from oxidative stress [93]. Histone modifications containing phosphorylation, methylation, and acetylation also are major components of epigenetic regulatory mechanisms [92].…”