Nanoparticles induce apoptosis via mediating diverse cellular pathways

Nanomaterials-induced programmed cell death: Focus on mitochondria

Nanomaterials are widely utilized in several domains, such as everyday life, societal manufacturing, and biomedical applications, which expand the potential for nanomaterials to penetrate biological barriers and interact with cells. Multiple studies have concentrated on the particular or improper utilization of nanomaterials, resulting in cellular death. The primary mode of cell death caused by nanotoxicity is programmable cell death, which includes apoptosis, ferroptosis, necroptosis, and pyroptosis. Based on our prior publications and latest research, mitochondria have a vital function in facilitating programmed cell death caused by nanomaterials, as well as initiating or transmitting death signal pathways associated with it. Therefore, this review takes mitochondria as the focal point to investigate the internal molecular mechanism of nanomaterial-induced programmed cell death, with the aim of identifying potential targets for prevention and treatment in related studies.

Anti-breast cancer activity of biosynthesized selenium nanoparticles using Bacillus coagulans supernatant

BACKGROUND

In the present study, Selenium Nanoparticles (SeNPs) were prepared using Bacillus coagulans, which is a type of Lactic Acid Bacteria (LAB), and then they were applied to treat breast cancer cells.

METHODS

The chemicophysical properties of the bioengineered SeNPs were investigated by Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), zeta potential, dynamic light scattering, Fourier Transform Infrared Spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction analysis (XRD). The cytotoxic potential of SeNPs was evaluated by MTT assay against MCF-7 breast cancer cell line. The expression levels of apoptotic genes including BAX, BCL2, VEGF, ERBB2, CASP3, CASP9, CCNE1, CCND1, MMP2 and MMP9 were determined by real-time PCR. The rate of apoptosis and necrosis of the cancer cells as well as the results of the cell cycle were evaluated by flow cytometry method.

RESULTS

The synthesized SeNPs had an average particle size of about 24-40 nm and a zeta potential of -16.1 mV, indicating the high stability of SeNPs. EDX results showed presence of SeNPs because amount of selenium in SeNPs was 86.6 % by weight. The cytotoxicity results showed a concentration-dependent effect against MCF-7 cells. The half-maximal inhibitory concentration (IC50) values of B. coagulans supernatant and SeNPs against breast cancer cells were 389.7 µg/mL and 17.56 µg/mL, respectively. In addition, SeNPs synthesized by the green process exhibited enhanced apoptotic potential in MCF-7 cancer cells compared with bacterial supernatants. Cancer cells treated with IC50 concentration of SeNPs induced 32 % apoptosis compared to untreated cells (3 % apoptosis). The gene expression levels of BAX, CASP3, and CASP9 were upregulated, while the expression levels of BCL2, CCNE1, CCND1, MMP2, MMP9, VEGF, and ERBB2 were downregulated after SeNPs treatment of cells. The potential of SeNPs to induce cell apoptosis was demonstrated by the increase in the expression level of BAX gene and the decrease in the expression level of BCL2 after treatment of cancer cells with SeNPs.

CONCLUSION

The obtained results indicated that SeNPs had strong potential to induce significant cell apoptosis and are cytotoxic against the MCF-7 cancer cell line.

Exploring the Potential of Montmorillonite as an Antiproliferative Nanoagent against MDA-MB-231 and MCF-7 Human Breast Cancer Cells

Unlike MCF-7 cells, MDA-MB-231 cells are unresponsive to hormone therapy and often show resistance to chemotherapy and radiotherapy. Here, the antiproliferative effect of biocompatible montmorillonite (Mt) nanosheets on MDA-MB-231 and MCF-7 human breast cancer cells was evaluated by MTT assay, flow cytometry, and qRT-PCR. The results showed that the Mt IC50 for MDA-MB-231 and MCF-7 cells in a fetal bovine serum (FBS)-free medium was ~50 and ~200 µg/mL, and in 10% FBS medium ~400 and ~2000 µg/mL, respectively. Mt caused apoptosis in both cells by regulating related genes including Cas-3, P53, and P62 in MDA-MB-231 cells and Bcl-2, Cas-8, Cas-9, P53, and P62 in MCF-7 cells. Also, Mt arrested MCF-7 cells in the G0/G1 phase by altering Cyclin-D1 and P21 expression, and caused sub-G1 arrest and necrosis in both cells, possibly through damaging the mitochondria. However, fewer gene expression changes and more sub-G1 arrest and necrosis were observed in MDA-MB-231 cells, confirming the higher vulnerability of MDA-MB-231 cells to Mt. Furthermore, MDA-MB-231 cells appeared to be much more vulnerable to Mt compared to other cell types, including normal lung fibroblast (MRC-5), colon cancer (HT-29), and liver cancer (HepG2) cells. The higher vulnerability of MDA-MB-231 cells to Mt was inferred to be due to their higher proliferation rate. Notably, Mt cytotoxicity was highly dependent on both the Mt concentration and serum level, which favors Mt for the local treatment of MDA-MB-231 cells. Based on these results, Mt can be considered as an antiproliferative nanoagent against MDA-MB-231 cells and may be useful in the development of local nanoparticle-based therapies.

The Alleviative Efficacy of Vitamins A, C, and E Against Zinc Oxide Nanoparticles-Induced Hepatic Damage by Reducing Apoptosis in Rats

Nanoparticles are vastly exploited in today's technology. However, it is realized that exposure to high concentrations of nanoparticles (NPs) may have adverse effects on human health. According to previous reports, zinc oxide (ZnO) NPs cause toxic effects in tissues via inducing apoptosis. The current work was designed to evaluate possible protective activities of vitamins (Vits) A, C, and E against ZnO NPs-induced apoptosis in the liver of rats. To this aim, fifty-four adult male Wistar rats were randomly distributed into nine groups (n = 6 rats for each group), namely, Control1 (water), Control2 (olive oil), Vit A (1000 IU/kg), Vit C (200 mg/kg), Vit E (100 IU/kg), ZnO (200 mg/kg), ZnO + VitA, ZnO + VitC, and ZnO + VitE. To investigate apoptosis, the mRNA and protein expression of Bcl-2-associated X (Bax) and B-cell lymphoma protein 2 (Bcl-2) were examined by qRT-PCR and western blot techniques. The mRNA and protein expression of TNF-α as well as the activity of caspase 3,7 were also measured. The results revealed that ZnO NPs considerably enhance the ratio of Bax to Bcl-2 mRNA and protein expression as well as the activity of caspase 3,7 compared to the control group. Furthermore, the findings implied that the elevated level of TNF-α may link with ZnO NPs-mediated apoptosis in the liver of rats. More importantly, Vits A, C, and E exhibited ameliorative properties against apoptosis-inducing effects of ZnO NPs. Thus, administration of Vits A, C, and E may be effective in preventing liver damage and apoptosis caused by ZnO NPs.

Hemocytes of bivalve mollusks as cellular models in toxicological studies of metals and metal-based nanomaterials

Understanding the impacts of environmental pollutants on immune systems is indispensable in ecological and health risk assessments due to the significance of normal immunological functions in all living organisms. Bivalves as sentinel organisms with vital ecological importance are widely distributed in aquatic environments and their innate immune systems are the sensitive targets of environmental pollutants. As the central component of innate immunity, bivalve hemocytes are endowed with specialized endolysosomal systems for particle internalization and metal detoxification. These intrinsic biological features make them a unique cellular model for metal- and nano-immunotoxicology research. In this review, we firstly provided a general overview of bivalve's innate immunity and the classification and immune functions of hemocytes. We then summarized the recent progress on the interactions of metals and nanoparticles with bivalve hemocytes, with emphasis on the involvement of hemocytes in metal regulation and detoxification, the interactions of hemocytes and nanoparticles at eco/bio-nano interface and hemocyte-mediated immune responses to the exposure of metals and nanoparticles. Finally, we proposed the key knowledge gaps and future research priorities in deciphering the fundamental biological processes of the interactions of environmental pollutants with the innate immune system of bivalves as well as in developing bivalve hemocytes into a promising cellular model for nano-immuno-safety assessment.

Silver Nanoparticles Exert Apoptotic Activity in Bladder Cancer 5637 Cells Through Alteration of Bax/Bcl-2 Genes Expression

Bladder cancer is defined as a urinary tract malignancy that threatens men's and women's health. Due to the side effects of common chemotherapies, novel therapeutic strategies are necessary to overcome the issues concerning bladder cancer treatments. Nanotechnology has been suggested as a means to develop the next-generation objectives of cancer diagnosis and treatment among various novel therapies. Owing to the special characteristics that they can offer, silver nanoparticles (AgNPs) were investigated in this study to evaluate their apoptotic impact on bladder cancer 5637 cells. In this study, an MTT assay was conducted and appropriate concentrations of AgNPs were selected. Moreover, reactive oxygen species (ROS) production and apoptosis levels were determined using fluorimetric and Annexin/PI flow cytometry assays, respectively. Moreover, the activity of caspase 3,7, mRNA expression of Bax (Bcl-2-associated X) and Bcl-2 (B-cell lymphoma 2) were assessed based on colorimetric and qRT-PCR methods, respectively. The results indicated that AgNPs can significantly reduce the viability of 5637 cells in a dose-dependent mode as well as having the ability to elevate ROS production. Flow cytometry data showed that AgNPs lead to a remarkable increase in the apoptosis rate as compared with the control. Consistent with this, the induction of apoptosis was revealed by the overexpression of Bax, accompanied by a reduction in Bcl-2 expression compared to the control. Furthermore, AgNPs remarkably stimulated caspase 3,7 activation. In summary, AgNPs can mediate apoptosis in 5637 cells via excessive ROS formation, up-regulating Bax/Bcl-2 expression, and caspase 3,7 activation.

Gold nanoparticles induce apoptosis in HCT-116 colon cancer cell line

INTRODUCTION

This study aimed to investigate the apoptotic and anti-cancer effect of gold nanoparticles (AuNPs) on apoptosis in HCT-116 colon cancer cells.

MATERIALS AND METHODS

The level of ROS and apoptosis were determined by fluorimetric method and flow cytometry and Hoechst 33,258 staining, respectively. Furthermore, the mRNA expression of Bax, Bcl-2, CCNB1, P53 genes was evaluated by qRT-PCR method in HCT116 cells.

RESULTS

The experimental results of this study showed that treatment with nanoparticles led to a significant increase in expression of Bax, P53 genes and a significant decrease in the expression of Bcl-2, CCNB1 genes at concentrations of 25 and 50 µg/ml during 48 h of incubation, compared to control cells (p < 0.05). The flow cytometric results (Annexin-pI) and Hoechst 33,258 staining also showed a significant increase in the level of apoptosis in the treated cells, depending on the concentration and time.

CONCLUSIONS

The results of this study showed that AuNPs cause apoptosis at the half-maximal inhibitory concentration in the HCT-116 tumor cells during 48 h of incubation.

Anticancer Effects of Gold Nanoparticles by Inducing Apoptosis in Bladder Cancer 5637 Cells

Nanotechnology is a developing and revolutionary science that has been widely recommended for diagnosis and treatment of cancer. Among the various nanoparticles used in nanotechnology, gold nanoparticles (AuNPs) have attracted much attentions due to their promising anticancer properties. Despite the potential advantages of AuNPs, their apoptotic and anti-angiogenic effects have not yet been reported on human bladder cancer 5637 cells. This motivated us to evaluate (reactive oxygen species) ROS-mediated apoptosis in 5637 cells. For this task, inhibitory effect of AuNPs was investigated after 24-h exposure to different concentrations of AuNPs by MTT assay. Also, apoptosis level was assessed by ROS production, flow cytometry, and Hoechst 33,258 staining. Besides, mRNA expression of B-cell lymphoma protein 2 (Bcl-2), Bcl-2-associated X (Bax), vascular endothelial growth factor A (VEGFA) genes, and caspase-3,7 activity were determined by qRT-PCR and colorimetric assay, respectively. Moreover, migration rate was evaluated by wound healing assay. MTT results demonstrate that AuNPs can reduce 5637-cell viability in a dose-dependent manner, while fluorimetric assay data show significant increased ROS production in 25 and 50 µg/ml-treated cells. It is also observed that AuNPs lead to Bax overexpression and downregulation of Bcl-2 and VEGFA genes. In line with this, flow cytometry results show increased levels of apoptosis in 25 and 50 µg/ml AuNP-treated cells (p < 0.05). Similarly, Hoechst staining indicates a remarkable increase in cells with apoptotic morphology after treating with AuNPs. Overall, our findings show that AuNPs significantly provoke ROS production, induce apoptosis, and suppress cell migration in bladder cancer 5637 cells.

Engineered nanomaterials induce alterations in biological barriers: focus on paracellular permeability

Engineered nanoparticles (ENPs) are widely used in medical diagnosis and treatment, as food additives and as energy materials. ENPs may exert adverse or beneficial effects on the human body, which may be linked to interactions with biological barriers. In this review, the authors summarize the influences of four typical metal/metal oxide nanomaterials (Ag, TiO₂, Au, ZnO nanoparticles) on the paracellular permeability of biological barriers. Disruptions on tight junctions, adhesion junctions, gap junctions and desmosomes via complex signaling pathways, such as the MAPK, PKC and ROCK signaling pathways, affect paracellular permeability. Reactive oxygen species and cytokines underlie the mechanism of ENP-triggered alterations in paracellular permeability. This review provides the information necessary for the cautious application of nanoparticles in medicine and life sciences in the future.

In situ High-Throughput Single-Cell Analysis Reveals the Crosstalk between Nanoparticle-Induced Cell Responses

Nanomaterials are widely used in a variety of industrial, biological, and medical applications. Therefore, high concerns about their possible impact on human and environmental health have been raised. Here, we describe a high-throughput single-cell imaging method to reveal the crosstalk among quantum dot (QDot)-induced ROS generation, apoptosis, and changes in nucleus size in macrophages. In triple marker combinations, we assessed the correlations of three QDot-induced cellular responses via divided subsets based on single-cell analysis. In contrast to the results obtained from the cell population, we demonstrated that the change in nucleus size was positively correlated with ROS generation. We found that QDot exposure induced ROS generation, which led to cell apoptosis, followed by a change in nucleus size. In general, these observations on crosstalk of cellular responses provide detailed insights into the heterogeneity of nanoparticle exposure.

The Use of Alternative Strategies for Enhanced Nanoparticle Delivery to Solid Tumors

Nanomaterial (NM) delivery to solid tumors has been the focus of intense research for over a decade. Classically, scientists have tried to improve NM delivery by employing passive or active targeting strategies, making use of the so-called enhanced permeability and retention (EPR) effect. This phenomenon is made possible due to the leaky tumor vasculature through which NMs can leave the bloodstream, traverse through the gaps in the endothelial lining of the vessels, and enter the tumor. Recent studies have shown that despite many efforts to employ the EPR effect, this process remains very poor. Furthermore, the role of the EPR effect has been called into question, where it has been suggested that NMs enter the tumor via active mechanisms and not through the endothelial gaps. In this review, we provide a short overview of the EPR and mechanisms to enhance it, after which we focus on alternative delivery strategies that do not solely rely on EPR in itself but can offer interesting pharmacological, physical, and biological solutions for enhanced delivery. We discuss the strengths and shortcomings of these different strategies and suggest combinatorial approaches as the ideal path forward.

The Differential Effect of Carbon Dots on Gene Expression and DNA Methylation of Human Embryonic Lung Fibroblasts as a Function of Surface Charge and Dose

This study presents a toxicological evaluation of two types of carbon dots (CD), similar in size (<10 nm) but differing in surface charge. Whole-genome mRNA and miRNA expression (RNAseq), as well as gene-specific DNA methylation changes, were analyzed in human embryonic lung fibroblasts (HEL 12469) after 4 h and 24 h exposure to concentrations of 10 and 50 µg/mL (for positive charged CD; pCD) or 10 and 100 µg/mL (for negative charged CD, nCD). The results showed a distinct response for the tested nanomaterials (NMs). The exposure to pCD induced the expression of a substantially lower number of mRNAs than those to nCD, with few commonly differentially expressed genes between the two CDs. For both CDs, the number of deregulated mRNAs increased with the dose and exposure time. The pathway analysis revealed a deregulation of processes associated with immune response, tumorigenesis and cell cycle regulation, after exposure to pCD. For nCD treatment, pathways relating to cell proliferation, apoptosis, oxidative stress, gene expression, and cycle regulation were detected. The expression of miRNAs followed a similar pattern: more pronounced changes after nCD exposure and few commonly differentially expressed miRNAs between the two CDs. For both CDs the pathway analysis based on miRNA-mRNA interactions, showed a deregulation of cancer-related pathways, immune processes and processes involved in extracellular matrix interactions. DNA methylation was not affected by exposure to any of the two CDs. In summary, although the tested CDs induced distinct responses on the level of mRNA and miRNA expression, pathway analyses revealed a potential common biological impact of both NMs independent of their surface charge.

Nanoparticles induce autophagy via mTOR pathway inhibition and reactive oxygen species generation

Due to their unique physicochemical properties, nanoparticles (NPs) have been increasingly developed for use in various fields. However, there has been both growing negative concerns with toxicity and positive realization of opportunities in nanomedicine, coming from the growing understanding of the associations between NPs and the human body, particularly relating to their cellular autophagic effects. This review summarizes NP-induced autophagy via the modulation of the mTOR signaling pathway and other associated signals including AMPK and ERK and also demonstrates how reactive oxygen species generation greatly underlies the regulation processes. The perspectives in this review aim to contribute to NP design, particularly in consideration of nanotoxicity and the potential for the precise application of NPs in nanomedicine.

Resveratrol Inhibits Oxidative Stress and Prevents Mitochondrial Damage Induced by Zinc Oxide Nanoparticles in Zebrafish (Danio rerio)

Despite their wide industrial use, Zinc oxide (ZnO) nanoparticles (NPs) exhibit a high toxic potential while concerns of their health-related risks are still present, urging additional in vivo clarification studies. Oxidative stress is recognized as the primary trigger of NP-associated toxicity, suggesting antioxidants as a promising counteractive approach. Here, we investigated the protective effect of the natural antioxidant resveratrol against ZnO NP-induced toxicity in vivo using the zebrafish model. Our findings demonstrate that resveratrol counteracts ZnO NP-induced zebrafish lethality preventing cardiac morphological and functional damage. NP-induced vascular structural abnormalities during embryonic fish development were significantly counteracted by resveratrol treatment. Mechanistically, we further showed that resveratrol inhibits ROS increase, prevents mitochondrial membrane potential dysfunction, and counteracts cell apoptosis/necrosis elicited by ZnO NP. Overall, our data provide further evidence demonstrating the primary role of oxidative stress in NP-induced damage, and highlight new insights concerning the protective mechanism of antioxidants against nanomaterial toxicity.

Nanosensors and particles: a technology frontier with pitfalls

As we are approaching 20 years after the US National Nanotechnology Initiative has been announced, whereby most of that funding was spend to engineer, characterize and bring nanoparticles and nanosensors to the market, it is timely to assess the progress made. Beyond revolutionizing nonmedical applications, including construction materials and the food industry, as well as in vitro medical diagnostics, the progress in bringing them into the clinic has been far slower than expected. Even though most of the advances in nanosensor and nanoparticle research and development have been paid for by disease-oriented funding agencies, much of the gained knowledge can now be applied to treat or learn more about our environment, including water, soil, microbes and plants. As the amount of engineered nanoparticles that enter our environment is currently exponentially increasing, much tighter attention needs to be paid to assessing their health risk. This is urgent as the asbestos story told us important lessons how financial interests arising from a rapid build up of a flourishing industry has blocked and is still preventing a worldwide ban on asbestos, nearly 100 years after the first health risks were reported.