Tissue-Specific Regulation of the Contents and Correlations of Mineral Elements in Hens by Zinc Oxide Nanoparticles

Zinc oxide nanoparticles induce toxicity in diffuse large B-cell lymphoma cell line U2932 via activating PINK1/Parkin-mediated mitophagy

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma. Zinc oxide (ZnO) nanoparticles have excellent anti-tumor properties in the biomedical field. The present study aimed to explore the underlying mechanism by which ZnO nanoparticles induce toxicity in DLBCL cells (U2932) via the PINK1/Parkin-mediated mitophagy pathway. After U2932 cells were exposed to various concentrations of ZnO nanoparticles, the cell survival rate, reactive oxygen species (ROS) generation, cell cycle arrest, and changes in the expression of PINK1, Parkin, P62, and LC3 were monitored. Moreover, we investigated monodansylcadaverine (MDC) fluorescence intensity and autophagosome and further validated the results using the autophagy inhibitor 3-methyladenine (3-MA). The results showed that ZnO nanoparticles could effectively inhibit the proliferation of U2932 cells and induce cell cycle arrest at the G0/G1 phases. Moreover, ZnO nanoparticles significantly increased ROS production, MDC fluorescence intensity, autophagosome formation, and the expression of PINK1, Parkin, and LC3, and decreased the expression of P62 in U2932 cells. In contrast, the autophagy level was reduced after the intervention of the 3-MA. Overall, ZnO nanoparticles can trigger PINK1/Parkin-mediated mitophagy signaling in U2932 cells, which may be a potential therapeutic approach for DLBCL.

Heavy metals interfere with plasma metabolites, including lipids and amino acids, in patients with breast cancer

The aim of the present study was to examine the association between plasma heavy metals and the metabolome in patients with breast cancer (BC), and the association with cancer development. Nuclear magnetic resonance was used to determine the metabolites involved and an inductively coupled plasma mass spectrometry system was used to quantify the heavy metals in the plasma samples. It was indicated that cadmium was significantly higher in the plasma of patients with BC compared with that in the control population (~15-fold increase). Chromium, arsenic and lead were also elevated in the plasma of patients with BC by ~3.24, 2.14 and 1.52 fold, respectively. A number of small molecules, including amino acids and salts, were altered in the plasma of patients with BC compared with the control population. Another notable finding in this investigation was that plasma lipid levels were elevated in patients with BC compared with those in the control population. The findings of the present study suggest that exposure to heavy metals, including cadmium, arsenic, chromium and lead, may influence blood lipid levels and other small molecule metabolites, which in turn may be involved in BC development. Further studies surrounding urinary heavy metals and the metabolome are required to further determine the impact of metals on metabolism and on BC development.

Evaluation of heavy metals and metabolites in the urine of patients with breast cancer

Epidemiologic studies demonstrated that the environment serves a crucial role in cancer development. Heavy metals, including arsenic (As), cadmium (cd), chromium (Cr), lead and mercury, are considered to be carcinogens or co-carcinogens. Furthermore, Cd has been detected in breast cancer (BC) tissue at high concentrations. The present study aimed to investigate the correlation between heavy metals detected in urine and urine metabolome of patients with BC, and their association with cancer development. Nuclear magnetic resonance was used to determine urine metabolites and an inductively coupled plasma mass spectrometry system was used to detect heavy metals in urine samples. The results demonstrated that Cd was markedly increased in the urine of patients with BC compared with the control population (approximately 2-fold). Cr and As were also increased in the urine of patients with BC. In addition, numerous small molecule metabolites were altered in the urine of patients with BC compared with the control population. This study also demonstrated that alterations in small molecule metabolites in the urine of patients with BC were very similar to results from a previous report. These findings indicated that environmental exposure to Cd, As, or Cr could influence the urine levels of metabolites, which may be involved in BC development. Further investigation is therefore required to examine a larger range of samples from different countries or areas in order to understand the impact of heavy metals on metabolism and BC development.

Zinc oxide nanoparticles induce human multiple myeloma cell death via reactive oxygen species and Cyt-C/Apaf-1/Caspase-9/Caspase-3 signaling pathway in vitro

BACKGROUND

Human multiple myeloma (MM) is a malignant and incurable B cell tumor. Zinc oxide nanoparticles (ZnO NPs) have been widely used in biomedical fields including anti-bacterial and anti-tumor. However, the influence of ZnO NPs on MM cells is still unclear. The present study aimed to investigate the effect of ZnO NPs on MM cell (a human myeloma-derived RPMI8226 cell line) death in vitro and the underlying mechanism.

METHODS

The morphology of ZnO NPs was characterized by transmission electron microscopy (TEM), and the inhibitory and apoptotic effect of ZnO NPs on human MM cells was monitored by a CCK-8 method and an Annexin V-FITC/PI assay. Meanwhile, the morphological change in the cells after exposure to ZnO NPs was observed by a light field microscope. Moreover, the effects of ZnO NPs on the ATP level, reactive oxygen species (ROS) generation, and apoptosis were separately explored by the DCFH-DA fluorescent probe, flow cytometry, and ATP bioluminescence assay. Moreover, the expression of cytochrome C (Cyt-C), Apaf-1, Caspase-9 and Caspase-3 at mRNA and protein levels was further determined by using quantitative PCR (Q-PCR) and western blotting. In the present study, the human peripheral blood mononuclear cells (PBMCs) were used as normal control samples for the relevant experiment.

RESULTS

The results indicated that ZnO NPs could significantly inhibit human MM cell proliferation and cell death in a time- and dose-dependent manner in vitro, and this outcome can be confirmed by cell morphology and apoptosis assay. Meanwhile, the results also showed that ZnO NPs could effectively increase ROS production and decrease ATP levels in human MM cells. ZnO NPs could also significantly elevate the expression of Cyt-C, Apaf-1, Caspase-9 and Caspase-3 at mRNA and protein levels, leading to cell death. By contrast, ZnO NPs showed little cytotoxic influence on PBMCs.

CONCLUSION

ZnO NPs can significantly induce human MM cell death in a time- and dose-dependent manner in vitro, decrease the ATP production and enhance the ROS generation. ZnO NPs can also increase Cyt-C, Apaf-1, Caspase-9 and Caspase-3 expression at mRNA and protein levels in human MM cells, and initiate MM cell apoptosis, indicating that Cyt-C, Apaf-1, Caspase-9 and Caspase-3 play crucial roles in ZnO NPs-induced, mitochondria-mediated apoptosis in human MM cells. Overall, ZnO NPs may be a potential agent in treating human multiple myeloma in clinical practice.

Zinc oxide nanoparticles induce murine photoreceptor cell death via mitochondria-related signaling pathway

Zinc oxide (ZnO) nanoparticles can exhibit toxic effect on cells and tissues, which may be involved in the excessive generation of reactive oxygen species (ROS) and the consequent mitochondria-mediated apoptotic pathway. Nevertheless, the detailed mechanism remains unclear. In this study, we explored the effects of ZnO nanoparticles on the expressions of cytochrome c, ATP level, mitochondrial membrane potential, ROS, apoptosis, total antioxidant enzyme activities and apoptotic-related protein levels in murine photoreceptor cells as well as the changes of proteomic profiling. Moreover, we also performed the bioinformatics analysis for the differentially expressed proteins. Our results show that ZnO nanoparticles induce the release of cytochorme c, decrease the intracellular ATP level, collapse the mitochondrial membrane potential, elevate the ROS level, inhibit total antioxidant enzyme activities and increase the Bax and Caspase 3 levels whereas it decrease the Bcl-2 expression, leading to cell death. Proteomic analysis reveals the differentially expressed proteins are involved in cytochrome c oxidase activity and oxidative phosphorylation. Protein-protein interaction analysis confirms the differentially expressed proteins are closely associated with the clusters related to apoptotic signaling pathway and oxidative phosphorylation-associated proteins. Our results indicate that mitochondria play a central role in ZnO nanoparticle-induced murine photoreceptor cell death.

Zinc Oxide Nanoparticle Caused Plasma Metabolomic Perturbations Correlate with Hepatic Steatosis

Zinc oxide nanoparticles (ZnO NPs), known for their chemical stability and strong adsorption, are used in everyday items such as cosmetics, sunscreens, and prophylactic drugs. However, they have also been found to adversely affect organisms; previously we found that ZnO NPs disrupt pubertal ovarian development, inhibit embryonic development by upsetting γ-H2AX and NF-κB pathways, and even disturb skin stem cells. Non-targeted metabolomic analysis of biological organisms has been suggested as an unbiased tool for the investigation of perturbations in response to NPs and their underlying mechanisms. Although metabolomics has been used in nanotoxicological studies, very few reports have used it to investigate the effects of ZnO NPs exposure. In the current investigation, through a metabolomics-based approach, we discovered that ZnO NPs caused changes in plasma metabolites involved in anti-oxidative mechanisms, energy metabolism, and lipid metabolism in hen livers. These results are in line with earlier findings that ZnO NPs perturb the tricarboxylic acid cycle and in turn result in the use of alternative energy sources. We also found that ZnO NPs disturbed lipid metabolism in the liver and consequently impacted blood lipid balance. Changes in plasma metabolomes were correlated with hepatic steatosis.